version 4.0

forever loop is gone (use repeat without iteration count).
struct literal is now same as array literal [...] to avoid parsing ambiguity with scope blocks.

.gitignore

@@ -1,20 +1,20 @@
-**/.idea/
+.idea/workspace.xml
-/build/
+.idea/discord.xml
-/dist/
+build/
-/output/
+dist/
+output/
 .*cache/
 *.directory
 *.prg
-*.asm
 *.bin
 *.labels.txt
 *.vm.txt
 *.vice-mon-list
 docs/build
 out/
-**/*.interp
+parser/**/*.interp
-**/*.tokens
+parser/**/*.tokens
-
+parser/**/*.java
 *.py[cod]
 *.egg
 *.egg-info
@@ -25,7 +25,7 @@ __pycache__/
 parser.out
 parsetab.py
 .pytest_cache/
-compiler/src/prog8_kotlin.jar
-compiler/src/compiled_java
 .attach_pid*
 
+.gradle
+/prog8compiler.jar

.idea/.gitignore

@@ -0,0 +1,2 @@
+# Default ignored files
+/shelf/

.idea/dictionaries/irmen.xml

@@ -0,0 +1,3 @@
+<component name="ProjectDictionaryState">
+  <dictionary name="irmen" />
+</component>

.idea/inspectionProfiles/Project_Default.xml

@@ -0,0 +1,20 @@
+<component name="InspectionProjectProfileManager">
+  <profile version="1.0">
+    <option name="myName" value="Project Default" />
+    <inspection_tool class="DuplicatedCode" enabled="true" level="WEAK WARNING" enabled_by_default="true">
+      <Languages>
+        <language minSize="100" isEnabled="false" name="JavaScript" />
+        <language isEnabled="false" name="Groovy" />
+        <language isEnabled="false" name="Style Sheets" />
+        <language minSize="70" name="Kotlin" />
+        <language isEnabled="false" name="TypeScript" />
+        <language isEnabled="false" name="ActionScript" />
+      </Languages>
+    </inspection_tool>
+    <inspection_tool class="SpellCheckingInspection" enabled="true" level="TYPO" enabled_by_default="true">
+      <option name="processCode" value="false" />
+      <option name="processLiterals" value="true" />
+      <option name="processComments" value="false" />
+    </inspection_tool>
+  </profile>
+</component>

.idea/kotlinc.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="Kotlin2JvmCompilerArguments">
+    <option name="jvmTarget" value="1.8" />
+  </component>
+</project>

.idea/libraries/KotlinJavaRuntime.xml

@@ -0,0 +1,19 @@
+<component name="libraryTable">
+  <library name="KotlinJavaRuntime">
+    <CLASSES>
+      <root url="jar://$KOTLIN_BUNDLED$/lib/kotlin-stdlib.jar!/" />
+      <root url="jar://$KOTLIN_BUNDLED$/lib/kotlin-reflect.jar!/" />
+      <root url="jar://$KOTLIN_BUNDLED$/lib/kotlin-test.jar!/" />
+      <root url="jar://$KOTLIN_BUNDLED$/lib/kotlin-stdlib-jdk7.jar!/" />
+      <root url="jar://$KOTLIN_BUNDLED$/lib/kotlin-stdlib-jdk8.jar!/" />
+    </CLASSES>
+    <JAVADOC />
+    <SOURCES>
+      <root url="jar://$KOTLIN_BUNDLED$/lib/kotlin-stdlib-sources.jar!/" />
+      <root url="jar://$KOTLIN_BUNDLED$/lib/kotlin-reflect-sources.jar!/" />
+      <root url="jar://$KOTLIN_BUNDLED$/lib/kotlin-test-sources.jar!/" />
+      <root url="jar://$KOTLIN_BUNDLED$/lib/kotlin-stdlib-jdk7-sources.jar!/" />
+      <root url="jar://$KOTLIN_BUNDLED$/lib/kotlin-stdlib-jdk8-sources.jar!/" />
+    </SOURCES>
+  </library>
+</component>

.idea/libraries/antlr_4_7_2_complete.xml

@@ -0,0 +1,9 @@
+<component name="libraryTable">
+  <library name="antlr-4.7.2-complete">
+    <CLASSES>
+      <root url="jar://$PROJECT_DIR$/parser/antlr/lib/antlr-4.7.2-complete.jar!/" />
+    </CLASSES>
+    <JAVADOC />
+    <SOURCES />
+  </library>
+</component>

.idea/libraries/antlr_4_8_complete.xml

@@ -0,0 +1,9 @@
+<component name="libraryTable">
+  <library name="antlr-4.8-complete">
+    <CLASSES>
+      <root url="jar://$PROJECT_DIR$/parser/antlr/lib/antlr-4.8-complete.jar!/" />
+    </CLASSES>
+    <JAVADOC />
+    <SOURCES />
+  </library>
+</component>

.idea/libraries/antlr_runtime_4_7_2.xml

@@ -0,0 +1,9 @@
+<component name="libraryTable">
+  <library name="antlr-runtime-4.7.2">
+    <CLASSES>
+      <root url="jar://$PROJECT_DIR$/parser/antlr/lib/antlr-runtime-4.7.2.jar!/" />
+    </CLASSES>
+    <JAVADOC />
+    <SOURCES />
+  </library>
+</component>

.idea/libraries/antlr_runtime_4_8.xml

@@ -0,0 +1,9 @@
+<component name="libraryTable">
+  <library name="antlr-runtime-4.8">
+    <CLASSES>
+      <root url="jar://$PROJECT_DIR$/parser/antlr/lib/antlr-runtime-4.8.jar!/" />
+    </CLASSES>
+    <JAVADOC />
+    <SOURCES />
+  </library>
+</component>

.idea/libraries/kotlinx_cli_jvm_0_1_0_dev_5.xml

@@ -0,0 +1,9 @@
+<component name="libraryTable">
+  <library name="kotlinx-cli-jvm-0.1.0-dev-5">
+    <CLASSES>
+      <root url="jar://$PROJECT_DIR$/compiler/lib/kotlinx-cli-jvm-0.1.0-dev-5.jar!/" />
+    </CLASSES>
+    <JAVADOC />
+    <SOURCES />
+  </library>
+</component>

.idea/libraries/unittest_libs.xml

@@ -0,0 +1,10 @@
+<component name="libraryTable">
+  <library name="unittest-libs">
+    <CLASSES>
+      <root url="file://$PROJECT_DIR$/compiler/lib" />
+    </CLASSES>
+    <JAVADOC />
+    <SOURCES />
+    <jarDirectory url="file://$PROJECT_DIR$/compiler/lib" recursive="false" />
+  </library>
+</component>

.idea/markdown-navigator-enh.xml

@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="MarkdownEnhProjectSettings">
+    <AnnotatorSettings targetHasSpaces="true" linkCaseMismatch="true" wikiCaseMismatch="true" wikiLinkHasDashes="true" notUnderWikiHome="true" targetNotWikiPageExt="true" notUnderSourceWikiHome="true" targetNameHasAnchor="true" targetPathHasAnchor="true" wikiLinkHasSlash="true" wikiLinkHasSubdir="true" wikiLinkHasOnlyAnchor="true" linkTargetsWikiHasExt="true" linkTargetsWikiHasBadExt="true" notUnderSameRepo="true" targetNotUnderVcs="false" linkNeedsExt="true" linkHasBadExt="true" linkTargetNeedsExt="true" linkTargetHasBadExt="true" wikiLinkNotInWiki="true" imageTargetNotInRaw="true" repoRelativeAcrossVcsRoots="true" multipleWikiTargetsMatch="true" unresolvedLinkReference="true" linkIsIgnored="true" anchorIsIgnored="true" anchorIsUnresolved="true" anchorLineReferenceIsUnresolved="true" anchorLineReferenceFormat="true" anchorHasDuplicates="true" abbreviationDuplicates="true" abbreviationNotUsed="true" attributeIdDuplicateDefinition="true" attributeIdNotUsed="true" footnoteDuplicateDefinition="true" footnoteUnresolved="true" footnoteDuplicates="true" footnoteNotUsed="true" macroDuplicateDefinition="true" macroUnresolved="true" macroDuplicates="true" macroNotUsed="true" referenceDuplicateDefinition="true" referenceUnresolved="true" referenceDuplicates="true" referenceNotUsed="true" referenceUnresolvedNumericId="true" enumRefDuplicateDefinition="true" enumRefUnresolved="true" enumRefDuplicates="true" enumRefNotUsed="true" enumRefLinkUnresolved="true" enumRefLinkDuplicates="true" simTocUpdateNeeded="true" simTocTitleSpaceNeeded="true" />
+    <HtmlExportSettings updateOnSave="false" parentDir="" targetDir="" cssDir="css" scriptDir="js" plainHtml="false" imageDir="" copyLinkedImages="false" imagePathType="0" targetPathType="2" targetExt="" useTargetExt="false" noCssNoScripts="false" useElementStyleAttribute="false" linkToExportedHtml="true" exportOnSettingsChange="true" regenerateOnProjectOpen="false" linkFormatType="HTTP_ABSOLUTE" />
+    <LinkMapSettings>
+      <textMaps />
+    </LinkMapSettings>
+  </component>
+  <component name="MarkdownNavigatorHistory">
+    <PasteImageHistory checkeredTransparentBackground="false" filename="image" directory="" onPasteImageTargetRef="3" onPasteLinkText="0" onPasteImageElement="1" onPasteLinkElement="1" onPasteReferenceElement="2" cornerRadius="20" borderColor="0" transparentColor="16777215" borderWidth="1" trimTop="0" trimBottom="0" trimLeft="0" trimRight="0" transparent="false" roundCorners="false" showPreview="true" bordered="false" scaled="false" cropped="false" hideInapplicableOperations="false" preserveLinkFormat="false" scale="50" scalingInterpolation="1" transparentTolerance="0" saveAsDefaultOnOK="false" linkFormat="0" addHighlights="false" showHighlightCoordinates="true" showHighlights="false" mouseSelectionAddsHighlight="false" outerFilled="false" outerFillColor="0" outerFillTransparent="true" outerFillAlpha="30">
+      <highlightList />
+      <directories />
+      <filenames />
+    </PasteImageHistory>
+    <CopyImageHistory checkeredTransparentBackground="false" filename="image" directory="" onPasteImageTargetRef="3" onPasteLinkText="0" onPasteImageElement="1" onPasteLinkElement="1" onPasteReferenceElement="2" cornerRadius="20" borderColor="0" transparentColor="16777215" borderWidth="1" trimTop="0" trimBottom="0" trimLeft="0" trimRight="0" transparent="false" roundCorners="false" showPreview="true" bordered="false" scaled="false" cropped="false" hideInapplicableOperations="false" preserveLinkFormat="false" scale="50" scalingInterpolation="1" transparentTolerance="0" saveAsDefaultOnOK="false" linkFormat="0" addHighlights="false" showHighlightCoordinates="true" showHighlights="false" mouseSelectionAddsHighlight="false" outerFilled="false" outerFillColor="0" outerFillTransparent="true" outerFillAlpha="30">
+      <highlightList />
+      <directories />
+      <filenames />
+    </CopyImageHistory>
+    <PasteLinkHistory onPasteImageTargetRef="3" onPasteTargetRef="1" onPasteLinkText="0" onPasteImageElement="1" onPasteLinkElement="1" onPasteWikiElement="2" onPasteReferenceElement="2" hideInapplicableOperations="false" preserveLinkFormat="false" useHeadingForLinkText="false" linkFormat="0" saveAsDefaultOnOK="false" />
+    <TableToJsonHistory>
+      <entries />
+    </TableToJsonHistory>
+    <TableSortHistory>
+      <entries />
+    </TableSortHistory>
+  </component>
+</project>

.idea/markdown-navigator.xml

@@ -0,0 +1,57 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="FlexmarkProjectSettings">
+    <FlexmarkHtmlSettings flexmarkSpecExampleRendering="0" flexmarkSpecExampleRenderHtml="false">
+      <flexmarkSectionLanguages>
+        <option name="1" value="Markdown" />
+        <option name="2" value="HTML" />
+        <option name="3" value="flexmark-ast:1" />
+      </flexmarkSectionLanguages>
+    </FlexmarkHtmlSettings>
+  </component>
+  <component name="MarkdownProjectSettings">
+    <PreviewSettings splitEditorLayout="SPLIT" splitEditorPreview="PREVIEW" useGrayscaleRendering="false" zoomFactor="1.0" maxImageWidth="0" synchronizePreviewPosition="true" highlightPreviewType="LINE" highlightFadeOut="5" highlightOnTyping="true" synchronizeSourcePosition="true" verticallyAlignSourceAndPreviewSyncPosition="true" showSearchHighlightsInPreview="true" showSelectionInPreview="true" lastLayoutSetsDefault="false">
+      <PanelProvider>
+        <provider providerId="com.vladsch.md.nav.editor.javafx.html.panel" providerName="JavaFX WebView" />
+      </PanelProvider>
+    </PreviewSettings>
+    <ParserSettings gitHubSyntaxChange="false" correctedInvalidSettings="false" emojiShortcuts="1" emojiImages="0">
+      <PegdownExtensions>
+        <option name="ANCHORLINKS" value="true" />
+        <option name="ATXHEADERSPACE" value="true" />
+        <option name="FENCED_CODE_BLOCKS" value="true" />
+        <option name="INTELLIJ_DUMMY_IDENTIFIER" value="true" />
+        <option name="RELAXEDHRULES" value="true" />
+        <option name="STRIKETHROUGH" value="true" />
+        <option name="TABLES" value="true" />
+        <option name="TASKLISTITEMS" value="true" />
+      </PegdownExtensions>
+      <ParserOptions>
+        <option name="COMMONMARK_LISTS" value="true" />
+        <option name="EMOJI_SHORTCUTS" value="true" />
+        <option name="GFM_TABLE_RENDERING" value="true" />
+        <option name="PRODUCTION_SPEC_PARSER" value="true" />
+        <option name="SIM_TOC_BLANK_LINE_SPACER" value="true" />
+      </ParserOptions>
+    </ParserSettings>
+    <HtmlSettings headerTopEnabled="false" headerBottomEnabled="false" bodyTopEnabled="false" bodyBottomEnabled="false" addPageHeader="false" imageUriSerials="false" addDocTypeHtml="true" noParaTags="false" plantUmlConversion="0">
+      <GeneratorProvider>
+        <provider providerId="com.vladsch.md.nav.editor.javafx.html.generator" providerName="JavaFx HTML Generator" />
+      </GeneratorProvider>
+      <headerTop />
+      <headerBottom />
+      <bodyTop />
+      <bodyBottom />
+    </HtmlSettings>
+    <CssSettings previewScheme="UI_SCHEME" cssUri="" isCssUriEnabled="false" isCssUriSerial="true" isCssTextEnabled="false" isDynamicPageWidth="true">
+      <StylesheetProvider>
+        <provider providerId="com.vladsch.md.nav.editor.javafx.html.css" providerName="Default JavaFx Stylesheet" />
+      </StylesheetProvider>
+      <ScriptProviders>
+        <provider providerId="com.vladsch.md.nav.editor.hljs.html.script" providerName="HighlightJS Script" />
+      </ScriptProviders>
+      <cssText />
+      <cssUriHistory />
+    </CssSettings>
+  </component>
+</project>

.idea/misc.xml

@@ -0,0 +1,22 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="ANTLRGenerationPreferences">
+    <option name="perGrammarGenerationSettings">
+      <list>
+        <PerGrammarGenerationSettings>
+          <option name="fileName" value="$PROJECT_DIR$/parser/antlr/prog8.g4" />
+          <option name="autoGen" value="true" />
+          <option name="outputDir" value="$PROJECT_DIR$/parser/src/prog8/parser" />
+          <option name="libDir" value="" />
+          <option name="encoding" value="" />
+          <option name="pkg" value="" />
+          <option name="language" value="" />
+          <option name="generateListener" value="false" />
+        </PerGrammarGenerationSettings>
+      </list>
+    </option>
+  </component>
+  <component name="ProjectRootManager" version="2" languageLevel="JDK_1_8" default="false" project-jdk-name="Kotlin SDK" project-jdk-type="KotlinSDK">
+    <output url="file://$PROJECT_DIR$/out" />
+  </component>
+</project>

.idea/modules.xml

@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="ProjectModuleManager">
+    <modules>
+      <module fileurl="file://$PROJECT_DIR$/compiler/compiler.iml" filepath="$PROJECT_DIR$/compiler/compiler.iml" />
+      <module fileurl="file://$PROJECT_DIR$/docs/docs.iml" filepath="$PROJECT_DIR$/docs/docs.iml" />
+      <module fileurl="file://$PROJECT_DIR$/examples/examples.iml" filepath="$PROJECT_DIR$/examples/examples.iml" />
+      <module fileurl="file://$PROJECT_DIR$/parser/parser.iml" filepath="$PROJECT_DIR$/parser/parser.iml" />
+    </modules>
+  </component>
+</project>

.idea/uiDesigner.xml

@@ -0,0 +1,124 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="Palette2">
+    <group name="Swing">
+      <item class="com.intellij.uiDesigner.HSpacer" tooltip-text="Horizontal Spacer" icon="/com/intellij/uiDesigner/icons/hspacer.png" removable="false" auto-create-binding="false" can-attach-label="false">
+        <default-constraints vsize-policy="1" hsize-policy="6" anchor="0" fill="1" />
+      </item>
+      <item class="com.intellij.uiDesigner.VSpacer" tooltip-text="Vertical Spacer" icon="/com/intellij/uiDesigner/icons/vspacer.png" removable="false" auto-create-binding="false" can-attach-label="false">
+        <default-constraints vsize-policy="6" hsize-policy="1" anchor="0" fill="2" />
+      </item>
+      <item class="javax.swing.JPanel" icon="/com/intellij/uiDesigner/icons/panel.png" removable="false" auto-create-binding="false" can-attach-label="false">
+        <default-constraints vsize-policy="3" hsize-policy="3" anchor="0" fill="3" />
+      </item>
+      <item class="javax.swing.JScrollPane" icon="/com/intellij/uiDesigner/icons/scrollPane.png" removable="false" auto-create-binding="false" can-attach-label="true">
+        <default-constraints vsize-policy="7" hsize-policy="7" anchor="0" fill="3" />
+      </item>
+      <item class="javax.swing.JButton" icon="/com/intellij/uiDesigner/icons/button.png" removable="false" auto-create-binding="true" can-attach-label="false">
+        <default-constraints vsize-policy="0" hsize-policy="3" anchor="0" fill="1" />
+        <initial-values>
+          <property name="text" value="Button" />
+        </initial-values>
+      </item>
+      <item class="javax.swing.JRadioButton" icon="/com/intellij/uiDesigner/icons/radioButton.png" removable="false" auto-create-binding="true" can-attach-label="false">
+        <default-constraints vsize-policy="0" hsize-policy="3" anchor="8" fill="0" />
+        <initial-values>
+          <property name="text" value="RadioButton" />
+        </initial-values>
+      </item>
+      <item class="javax.swing.JCheckBox" icon="/com/intellij/uiDesigner/icons/checkBox.png" removable="false" auto-create-binding="true" can-attach-label="false">
+        <default-constraints vsize-policy="0" hsize-policy="3" anchor="8" fill="0" />
+        <initial-values>
+          <property name="text" value="CheckBox" />
+        </initial-values>
+      </item>
+      <item class="javax.swing.JLabel" icon="/com/intellij/uiDesigner/icons/label.png" removable="false" auto-create-binding="false" can-attach-label="false">
+        <default-constraints vsize-policy="0" hsize-policy="0" anchor="8" fill="0" />
+        <initial-values>
+          <property name="text" value="Label" />
+        </initial-values>
+      </item>
+      <item class="javax.swing.JTextField" icon="/com/intellij/uiDesigner/icons/textField.png" removable="false" auto-create-binding="true" can-attach-label="true">
+        <default-constraints vsize-policy="0" hsize-policy="6" anchor="8" fill="1">
+          <preferred-size width="150" height="-1" />
+        </default-constraints>
+      </item>
+      <item class="javax.swing.JPasswordField" icon="/com/intellij/uiDesigner/icons/passwordField.png" removable="false" auto-create-binding="true" can-attach-label="true">
+        <default-constraints vsize-policy="0" hsize-policy="6" anchor="8" fill="1">
+          <preferred-size width="150" height="-1" />
+        </default-constraints>
+      </item>
+      <item class="javax.swing.JFormattedTextField" icon="/com/intellij/uiDesigner/icons/formattedTextField.png" removable="false" auto-create-binding="true" can-attach-label="true">
+        <default-constraints vsize-policy="0" hsize-policy="6" anchor="8" fill="1">
+          <preferred-size width="150" height="-1" />
+        </default-constraints>
+      </item>
+      <item class="javax.swing.JTextArea" icon="/com/intellij/uiDesigner/icons/textArea.png" removable="false" auto-create-binding="true" can-attach-label="true">
+        <default-constraints vsize-policy="6" hsize-policy="6" anchor="0" fill="3">
+          <preferred-size width="150" height="50" />
+        </default-constraints>
+      </item>
+      <item class="javax.swing.JTextPane" icon="/com/intellij/uiDesigner/icons/textPane.png" removable="false" auto-create-binding="true" can-attach-label="true">
+        <default-constraints vsize-policy="6" hsize-policy="6" anchor="0" fill="3">
+          <preferred-size width="150" height="50" />
+        </default-constraints>
+      </item>
+      <item class="javax.swing.JEditorPane" icon="/com/intellij/uiDesigner/icons/editorPane.png" removable="false" auto-create-binding="true" can-attach-label="true">
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+        </default-constraints>
+      </item>
+      <item class="javax.swing.JComboBox" icon="/com/intellij/uiDesigner/icons/comboBox.png" removable="false" auto-create-binding="true" can-attach-label="true">
+        <default-constraints vsize-policy="0" hsize-policy="2" anchor="8" fill="1" />
+      </item>
+      <item class="javax.swing.JTable" icon="/com/intellij/uiDesigner/icons/table.png" removable="false" auto-create-binding="true" can-attach-label="false">
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+      </item>
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+      </item>
+      <item class="javax.swing.JTree" icon="/com/intellij/uiDesigner/icons/tree.png" removable="false" auto-create-binding="true" can-attach-label="false">
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+        <default-constraints vsize-policy="0" hsize-policy="6" anchor="0" fill="1" />
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+      <item class="javax.swing.JToolBar" icon="/com/intellij/uiDesigner/icons/toolbar.png" removable="false" auto-create-binding="false" can-attach-label="false">
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+        </default-constraints>
+      </item>
+      <item class="javax.swing.JToolBar$Separator" icon="/com/intellij/uiDesigner/icons/toolbarSeparator.png" removable="false" auto-create-binding="false" can-attach-label="false">
+        <default-constraints vsize-policy="0" hsize-policy="0" anchor="0" fill="1" />
+      </item>
+      <item class="javax.swing.JScrollBar" icon="/com/intellij/uiDesigner/icons/scrollbar.png" removable="false" auto-create-binding="true" can-attach-label="false">
+        <default-constraints vsize-policy="6" hsize-policy="0" anchor="0" fill="2" />
+      </item>
+    </group>
+  </component>
+</project>

.idea/vcs.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="VcsDirectoryMappings">
+    <mapping directory="$PROJECT_DIR$" vcs="Git" />
+  </component>
+</project>

.travis.yml

@@ -0,0 +1,11 @@
+language: java
+sudo: false
+# jdk: openjdk8
+# dist: xenial
+
+before_install:
+  - chmod +x ./gradlew
+
+script:
+  - ./gradlew test
+

README.md

@@ -1,104 +1,120 @@
-Prog8 - Structured Programming Language for 8-bit 6502/6510 microprocessors
+[![saythanks](https://img.shields.io/badge/say-thanks-ff69b4.svg)](https://saythanks.io/to/irmen)
-===========================================================================
+[![Build Status](https://travis-ci.org/irmen/prog8.svg?branch=master)](https://travis-ci.org/irmen/prog8)
+[![Documentation](https://readthedocs.org/projects/prog8/badge/?version=latest)](https://prog8.readthedocs.io/)
+
+Prog8 - Structured Programming Language for 8-bit 6502/65c02 microprocessors
+============================================================================
 
 *Written by Irmen de Jong (irmen@razorvine.net)*
 
 *Software license: GNU GPL 3.0, see file LICENSE*
 
 
-This is a structured programming language for the 8-bit 6502/6510 microprocessor from the late 1970's and 1980's
+This is a structured programming language for the 8-bit 6502/6510/65c02 microprocessor from the late 1970's and 1980's
 as used in many home computers from that era. It is a medium to low level programming language,
 which aims to provide many conveniences over raw assembly code (even when using a macro assembler):
 
 - reduction of source code length
-- easier program understanding (because it's higher level, and more terse)
-- option to automatically run the compiled program in the Vice emulator  
 - modularity, symbol scoping, subroutines
-- subroutines have enforced input- and output parameter definitions
+- various data types other than just bytes (16-bit words, floats, strings)
-- various data types other than just bytes (16-bit words, floats, strings, 16-bit register pairs)
+- automatic variable allocations, automatic string and array variables and string sharing
-- automatic variable allocations, automatic string variables and string sharing
+- subroutines with an input- and output parameter signature
-- constant folding in expressions (compile-time evaluation)
+- constant folding in expressions
-- automatic type conversions
+- conditional branches
-- floating point operations
+- 'when' statement to provide a concise jump table alternative to if/elseif chains
+- structs to group together sets of variables and manipulate them at once
+- floating point operations  (requires the C64 Basic ROM routines for this)
 - abstracting away low level aspects such as ZeroPage handling, program startup, explicit memory addresses
+- various code optimizations (code structure, logical and numerical expressions, unused code removal...)
+- inline assembly allows you to have full control when every cycle or byte matters
+- many built-in functions such as ``sin``, ``cos``, ``rnd``, ``abs``, ``min``, ``max``, ``sqrt``, ``msb``, ``rol``, ``ror``, ``swap``, ``memset``, ``memcopy``, ``sort`` and ``reverse``
+
+Rapid edit-compile-run-debug cycle:
+
+- use a modern PC to do the work on
+- very quick compilation times
+- can automatically run the program in the Vice emulator after succesful compilation
 - breakpoints, that let the Vice emulator drop into the monitor if execution hits them
 - source code labels automatically loaded in Vice emulator so it can show them in disassembly
-- conditional gotos
+
-- various code optimizations (code structure, logical and numerical expressions, ...) 
+Prog8 is mainly targeted at the Commodore-64 machine.
+Preliminary support for the [CommanderX16](https://www.commanderx16.com) is available as a second compilation target.
+Contributions to improve these or to add support for other machines are welcome!
 
 
-It is mainly targeted at the Commodore-64 machine at this time.
+Documentation/manual
+--------------------
+https://prog8.readthedocs.io/
 
-Documentation is online at https://prog8.readthedocs.io/
+Required tools
-
+--------------
-
-Required tools:
----------------
 
 [64tass](https://sourceforge.net/projects/tass64/) - cross assembler. Install this on your shell path.
 A recent .exe version of this tool for Windows can be obtained from my [clone](https://github.com/irmen/64tass/releases) of this project.
 For other platforms it is very easy to compile it yourself (make ; make install).
 
-A **Java runtime (jre or jdk), version 8 or newer**  is required to run the packaged compiler.
+A **Java runtime (jre or jdk), version 8 or newer**  is required to run a prepackaged version of the compiler.
-If you want to build it from source, you'll need a Kotlin 1.3 SDK as well (or for instance,
+If you want to build it from source, you'll need a Java SDK + Kotlin 1.3.x SDK (or for instance,
 IntelliJ IDEA with the Kotlin plugin).
 
-It's handy to have a C-64 emulator or a real C-64 to run the programs on. The compiler assumes the presence
+It's handy to have an emulator (or a real machine perhaps!) to run the programs on. The compiler assumes the presence
-of the [Vice emulator](http://vice-emu.sourceforge.net/)
+of the [Vice emulator](http://vice-emu.sourceforge.net/)  for the C64 target,
+and the [x16emu emulator](https://github.com/commanderx16/x16-emulator) for the CommanderX16 target.
 
 
 Example code
 ------------
 
-When this code is compiled::
+This code calculates prime numbers using the Sieve of Eratosthenes algorithm::
 
-    %import c64lib
+    %import c64textio
-    %import c64utils
+    %zeropage basicsafe
-    %import c64flt
+
+    main {
+
+        ubyte[256] sieve
+        ubyte candidate_prime = 2
 
-    ~ main {
         sub start() {
-            ; set text color and activate lowercase charset
+            memset(sieve, 256, false)   ; clear the sieve
-            c64.COLOR = 13
+            txt.print("prime numbers up to 255:\n\n")
-            c64.VMCSB |= 2
+            ubyte amount=0
-
+            repeat {
-            ; use optimized routine to write text
+                ubyte prime = find_next_prime()
-            c64scr.print("Hello!\n")
+                if prime==0
-
+                    break
-            ; use iteration to write text
+                txt.print_ub(prime)
-            str question = "How are you?\n"
+                txt.print(", ")
-            for ubyte char in question
+                amount++
-                c64.CHROUT(char)
+            }
-
-            ; use indexed loop to write characters
-            str bye = "Goodbye!\n"
-            for ubyte c in 0 to len(bye)
-                c64.CHROUT(bye[c])
-
-
-            float clock_seconds = ((mkword(c64.TIME_LO, c64.TIME_MID) as float)
-                                    + (c64.TIME_HI as float)*65536.0)
-                                     / 60
-            float hours = floor(clock_seconds / 3600)
-            clock_seconds -= hours*3600
-            float minutes = floor(clock_seconds / 60)
-            clock_seconds = floor(clock_seconds - minutes * 60.0)
-
-            c64scr.print("system time in ti$ is ")
-            c64flt.print_f(hours)
-            c64.CHROUT(':')
-            c64flt.print_f(minutes)
-            c64.CHROUT(':')
-            c64flt.print_f(clock_seconds)
             c64.CHROUT('\n')
+            txt.print("number of primes (expected 54): ")
+            txt.print_ub(amount)
+            c64.CHROUT('\n')
+        }
+
+        sub find_next_prime() -> ubyte {
+            while sieve[candidate_prime] {
+                candidate_prime++
+                if candidate_prime==0
+                    return 0        ; we wrapped; no more primes available
+            }
+            ; found next one, mark the multiples and return it.
+            sieve[candidate_prime] = true
+            uword multiple = candidate_prime
+
+            while multiple < len(sieve) {
+                sieve[lsb(multiple)] = true
+                multiple += candidate_prime
+            }
+            return candidate_prime
         }
     }
 
 
+when compiled an ran on a C-64 you'll get:
 
-you get a program that outputs this when loaded on a C-64:
+![c64 screen](docs/source/_static/primes_example.png)
-
-![c64 screen](docs/source/_static/hello_screen.png)
 
 
 One of the included examples (wizzine.p8) animates a bunch of sprite balloons and looks like this:
@@ -109,3 +125,6 @@ Another example (cube3d-sprites.p8) draws the vertices of a rotating 3d cube:
 
 ![cube3d screen](docs/source/_static/cube3d.png)
 
+If you want to play a video game, a fully working Tetris clone is included in the examples:
+
+![tehtriz_screen](docs/source/_static/tehtriz.png)

build_the_compiler.sh

@@ -1,31 +0,0 @@
-#!/usr/bin/env bash
-
-echo "Compiling the parser..."
-java -jar ./parser/antlr/lib/antlr-4.7.2-complete.jar -o ./parser/src/prog8/parser -Xexact-output-dir -no-listener -no-visitor -package prog8.parser ./parser/antlr/prog8.g4
-
-
-PARSER_CLASSES=./out/production/parser
-COMPILER_JAR=prog8compiler.jar
-ANTLR_RUNTIME=./parser/antlr/lib/antlr-runtime-4.7.2.jar
-
-mkdir -p ${PARSER_CLASSES}
-javac  -d ${PARSER_CLASSES} -cp ${ANTLR_RUNTIME} ./parser/src/prog8/parser/prog8Lexer.java  ./parser/src/prog8/parser/prog8Parser.java
-
-echo "Compiling the compiler itself..."
-kotlinc -verbose -include-runtime -d ${COMPILER_JAR} -cp ${ANTLR_RUNTIME}:${PARSER_CLASSES} ./compiler/src/prog8
-
-echo "Finalizing the compiler jar file..."
-# add the antlr parser classes
-jar ufe ${COMPILER_JAR} prog8.CompilerMainKt -C ${PARSER_CLASSES} prog8
-
-# add the resources
-jar uf ${COMPILER_JAR} -C ./compiler/res .
-
-# add the antlr runtime classes
-rm -rf antlr_runtime_extraction
-mkdir antlr_runtime_extraction
-(cd antlr_runtime_extraction; jar xf ../${ANTLR_RUNTIME})
-jar uf ${COMPILER_JAR} -C antlr_runtime_extraction org
-rm -rf antlr_runtime_extraction
-
-echo "Done!"

compiler/build.gradle

@@ -0,0 +1,116 @@
+buildscript {
+    dependencies {
+        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:1.4.0"
+    }
+}
+
+plugins {
+    // id "org.jetbrains.kotlin.jvm" version "1.4.0"
+    id 'application'
+    id 'org.jetbrains.dokka' version "0.9.18"
+    id 'com.github.johnrengelman.shadow' version '5.2.0'
+    id 'java'
+}
+
+apply plugin: "kotlin"
+apply plugin: "java"
+
+targetCompatibility = 1.8
+sourceCompatibility = 1.8
+
+repositories {
+    mavenLocal()
+    mavenCentral()
+    jcenter()
+    maven { url "https://dl.bintray.com/orangy/maven/" }
+}
+
+def prog8version = rootProject.file('compiler/res/version.txt').text.trim()
+
+dependencies {
+    implementation project(':parser')
+    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8"
+    // implementation "org.jetbrains.kotlin:kotlin-reflect"
+    implementation 'org.antlr:antlr4-runtime:4.8'
+    implementation 'org.jetbrains.kotlinx:kotlinx-cli-jvm:0.1.0-dev-5'
+    // implementation 'net.razorvine:ksim65:1.6'
+    // implementation "com.github.hypfvieh:dbus-java:3.2.0"
+    implementation project(':parser')
+
+    testImplementation "org.jetbrains.kotlin:kotlin-test-junit5"
+    testImplementation 'org.junit.jupiter:junit-jupiter-api:5.3.2'
+    testImplementation 'org.hamcrest:hamcrest-junit:2.0.0.0'
+    testRuntimeOnly 'org.junit.jupiter:junit-jupiter-engine:5.3.2'
+}
+
+compileKotlin {
+    kotlinOptions {
+        jvmTarget = "1.8"
+        // verbose = true
+        // freeCompilerArgs += "-XXLanguage:+NewInference"
+    }
+}
+
+compileTestKotlin {
+    kotlinOptions {
+        jvmTarget = "1.8"
+    }
+}
+
+sourceSets {
+    main {
+        java {
+            srcDirs = ["${project.projectDir}/src"]
+        }
+        resources {
+            srcDirs = ["${project.projectDir}/res"]
+        }
+    }
+    test {
+        java {
+            srcDirs = ["${project.projectDir}/test"]
+        }
+    }
+}
+
+startScripts.enabled = true
+
+application {
+    mainClassName = 'prog8.CompilerMainKt'
+    applicationName = 'p8compile'
+}
+
+artifacts {
+    archives shadowJar
+}
+
+
+shadowJar {
+    archiveBaseName = 'prog8compiler'
+    archiveVersion = prog8version
+    // minimize()
+}
+
+
+test {
+    // Enable JUnit 5 (Gradle 4.6+).
+    useJUnitPlatform()
+
+    // Always run tests, even when nothing changed.
+    dependsOn 'cleanTest'
+
+    // Show test results.
+    testLogging {
+        events "skipped", "failed"
+    }
+}
+
+
+dokka {
+    outputFormat = 'html'
+    outputDirectory = "$buildDir/kdoc"
+}
+
+task wrapper(type: Wrapper) {
+    gradleVersion = '6.1.1'
+}

compiler/compiler.iml

@@ -3,15 +3,17 @@
   <component name="NewModuleRootManager" inherit-compiler-output="true">
     <exclude-output />
     <content url="file://$MODULE_DIR$">
-      <sourceFolder url="file://$MODULE_DIR$/src" isTestSource="false" />
       <sourceFolder url="file://$MODULE_DIR$/res" type="java-resource" />
+      <sourceFolder url="file://$MODULE_DIR$/src" isTestSource="false" />
       <sourceFolder url="file://$MODULE_DIR$/test" isTestSource="true" />
+      <excludeFolder url="file://$MODULE_DIR$/build" />
     </content>
-    <orderEntry type="jdk" jdkName="1.8" jdkType="JavaSDK" />
+    <orderEntry type="jdk" jdkName="openjdk-11" jdkType="JavaSDK" />
     <orderEntry type="sourceFolder" forTests="false" />
     <orderEntry type="library" name="KotlinJavaRuntime" level="project" />
-    <orderEntry type="library" name="antlr-runtime-4.7.2" level="project" />
-    <orderEntry type="library" name="testlibs" level="project" />
     <orderEntry type="module" module-name="parser" />
+    <orderEntry type="library" name="unittest-libs" level="project" />
+    <orderEntry type="library" name="kotlinx-cli-jvm-0.1.0-dev-5" level="project" />
+    <orderEntry type="library" name="antlr-runtime-4.8" level="project" />
   </component>
 </module>

compiler/res/prog8lib/c64floats.asm

@@ -0,0 +1,751 @@
+; --- low level floating point assembly routines for the C64
+
+
+ub2float	.proc
+		; -- convert ubyte in SCRATCH_ZPB1 to float at address A/Y
+		;    clobbers A, Y
+		stx  P8ZP_SCRATCH_REG_X
+		sta  P8ZP_SCRATCH_W2
+		sty  P8ZP_SCRATCH_W2+1
+		ldy  P8ZP_SCRATCH_B1
+		jsr  FREADUY
+_fac_to_mem	ldx  P8ZP_SCRATCH_W2
+		ldy  P8ZP_SCRATCH_W2+1
+		jsr  MOVMF
+		ldx  P8ZP_SCRATCH_REG_X
+		rts
+		.pend
+
+b2float		.proc
+		; -- convert byte in SCRATCH_ZPB1 to float at address A/Y
+		;    clobbers A, Y
+		stx  P8ZP_SCRATCH_REG_X
+		sta  P8ZP_SCRATCH_W2
+		sty  P8ZP_SCRATCH_W2+1
+		lda  P8ZP_SCRATCH_B1
+		jsr  FREADSA
+		jmp  ub2float._fac_to_mem
+		.pend
+
+uw2float	.proc
+		; -- convert uword in SCRATCH_ZPWORD1 to float at address A/Y
+		stx  P8ZP_SCRATCH_REG_X
+		sta  P8ZP_SCRATCH_W2
+		sty  P8ZP_SCRATCH_W2+1
+		lda  P8ZP_SCRATCH_W1
+		ldy  P8ZP_SCRATCH_W1+1
+		jsr  GIVUAYFAY
+		jmp  ub2float._fac_to_mem
+		.pend
+
+w2float		.proc
+		; -- convert word in SCRATCH_ZPWORD1 to float at address A/Y
+		stx  P8ZP_SCRATCH_REG_X
+		sta  P8ZP_SCRATCH_W2
+		sty  P8ZP_SCRATCH_W2+1
+		ldy  P8ZP_SCRATCH_W1
+		lda  P8ZP_SCRATCH_W1+1
+		jsr  GIVAYF
+		jmp  ub2float._fac_to_mem
+		.pend
+
+stack_b2float	.proc
+		; -- b2float operating on the stack
+		inx
+		lda  P8ESTACK_LO,x
+		stx  P8ZP_SCRATCH_REG_X
+		jsr  FREADSA
+		jmp  push_fac1_as_result
+		.pend
+
+stack_w2float	.proc
+		; -- w2float operating on the stack
+		inx
+		ldy  P8ESTACK_LO,x
+		lda  P8ESTACK_HI,x
+		stx  P8ZP_SCRATCH_REG_X
+		jsr  GIVAYF
+		jmp  push_fac1_as_result
+		.pend
+
+stack_ub2float	.proc
+		; -- ub2float operating on the stack
+		inx
+		lda  P8ESTACK_LO,x
+		stx  P8ZP_SCRATCH_REG_X
+		tay
+		jsr  FREADUY
+		jmp  push_fac1_as_result
+		.pend
+
+stack_uw2float	.proc
+		; -- uw2float operating on the stack
+		inx
+		lda  P8ESTACK_LO,x
+		ldy  P8ESTACK_HI,x
+		stx  P8ZP_SCRATCH_REG_X
+		jsr  GIVUAYFAY
+		jmp  push_fac1_as_result
+		.pend
+
+stack_float2w	.proc               ; also used for float2b
+		jsr  pop_float_fac1
+		stx  P8ZP_SCRATCH_REG_X
+		jsr  AYINT
+		ldx  P8ZP_SCRATCH_REG_X
+		lda  $64
+		sta  P8ESTACK_HI,x
+		lda  $65
+		sta  P8ESTACK_LO,x
+		dex
+		rts
+		.pend
+
+stack_float2uw	.proc               ; also used for float2ub
+		jsr  pop_float_fac1
+		stx  P8ZP_SCRATCH_REG_X
+		jsr  GETADR
+		ldx  P8ZP_SCRATCH_REG_X
+		sta  P8ESTACK_HI,x
+		tya
+		sta  P8ESTACK_LO,x
+		dex
+		rts
+		.pend
+
+push_float	.proc
+		; ---- push mflpt5 in A/Y onto stack
+		; (taking 3 stack positions = 6 bytes of which 1 is padding)
+		sta  P8ZP_SCRATCH_W1
+		sty  P8ZP_SCRATCH_W1+1
+		ldy  #0
+		lda  (P8ZP_SCRATCH_W1),y
+		sta  P8ESTACK_LO,x
+		iny
+		lda  (P8ZP_SCRATCH_W1),y
+		sta  P8ESTACK_HI,x
+		dex
+		iny
+		lda  (P8ZP_SCRATCH_W1),y
+		sta  P8ESTACK_LO,x
+		iny
+		lda  (P8ZP_SCRATCH_W1),y
+		sta  P8ESTACK_HI,x
+		dex
+		iny
+		lda  (P8ZP_SCRATCH_W1),y
+		sta  P8ESTACK_LO,x
+		dex
+		rts
+		.pend
+
+func_rndf	.proc
+		; -- put a random floating point value on the stack
+		stx  P8ZP_SCRATCH_REG
+		lda  #1
+		jsr  FREADSA
+		jsr  RND		; rng into fac1
+		ldx  #<_rndf_rnum5
+		ldy  #>_rndf_rnum5
+		jsr  MOVMF	; fac1 to mem X/Y
+		ldx  P8ZP_SCRATCH_REG
+		lda  #<_rndf_rnum5
+		ldy  #>_rndf_rnum5
+		jmp  push_float
+_rndf_rnum5	.byte  0,0,0,0,0
+		.pend
+
+pop_float	.proc
+		; ---- pops mflpt5 from stack to memory A/Y
+		; (frees 3 stack positions = 6 bytes of which 1 is padding)
+		sta  P8ZP_SCRATCH_W1
+		sty  P8ZP_SCRATCH_W1+1
+		ldy  #4
+		inx
+		lda  P8ESTACK_LO,x
+		sta  (P8ZP_SCRATCH_W1),y
+		dey
+		inx
+		lda  P8ESTACK_HI,x
+		sta  (P8ZP_SCRATCH_W1),y
+		dey
+		lda  P8ESTACK_LO,x
+		sta  (P8ZP_SCRATCH_W1),y
+		dey
+		inx
+		lda  P8ESTACK_HI,x
+		sta  (P8ZP_SCRATCH_W1),y
+		dey
+		lda  P8ESTACK_LO,x
+		sta  (P8ZP_SCRATCH_W1),y
+		rts
+		.pend
+
+pop_float_fac1	.proc
+		; -- pops float from stack into FAC1
+		lda  #<fmath_float1
+		ldy  #>fmath_float1
+		jsr  pop_float
+		lda  #<fmath_float1
+		ldy  #>fmath_float1
+		jmp  MOVFM
+		.pend
+
+pop_float_fac2	.proc
+		; -- pops float from stack into FAC2
+		lda  #<fmath_float1
+		ldy  #>fmath_float1
+		jsr  pop_float
+		lda  #<fmath_float1
+		ldy  #>fmath_float1
+		jmp  CONUPK
+		.pend
+
+pop_float_to_indexed_var	.proc
+		; -- pop the float on the stack, to the memory in the array at A/Y indexed by the byte on stack
+		sta  P8ZP_SCRATCH_W1
+		sty  P8ZP_SCRATCH_W1+1
+		jsr  prog8_lib.pop_index_times_5
+		jsr  prog8_lib.add_a_to_zpword
+		lda  P8ZP_SCRATCH_W1
+		ldy  P8ZP_SCRATCH_W1+1
+		jmp  pop_float
+		.pend
+
+copy_float	.proc
+		; -- copies the 5 bytes of the mflt value pointed to by SCRATCH_ZPWORD1,
+		;    into the 5 bytes pointed to by A/Y.  Clobbers A,Y.
+		sta  _target+1
+		sty  _target+2
+		ldy  #4
+_loop		lda  (P8ZP_SCRATCH_W1),y
+_target		sta  $ffff,y			; modified
+		dey
+		bpl  _loop
+		rts
+		.pend
+
+inc_var_f	.proc
+		; -- add 1 to float pointed to by A/Y
+		sta  P8ZP_SCRATCH_W1
+		sty  P8ZP_SCRATCH_W1+1
+		stx  P8ZP_SCRATCH_REG_X
+		jsr  MOVFM
+		lda  #<FL_FONE
+		ldy  #>FL_FONE
+		jsr  FADD
+		ldx  P8ZP_SCRATCH_W1
+		ldy  P8ZP_SCRATCH_W1+1
+		jsr  MOVMF
+		ldx  P8ZP_SCRATCH_REG_X
+		rts
+		.pend
+
+dec_var_f	.proc
+		; -- subtract 1 from float pointed to by A/Y
+		sta  P8ZP_SCRATCH_W1
+		sty  P8ZP_SCRATCH_W1+1
+		stx  P8ZP_SCRATCH_REG_X
+		lda  #<FL_FONE
+		ldy  #>FL_FONE
+		jsr  MOVFM
+		lda  P8ZP_SCRATCH_W1
+		ldy  P8ZP_SCRATCH_W1+1
+		jsr  FSUB
+		ldx  P8ZP_SCRATCH_W1
+		ldy  P8ZP_SCRATCH_W1+1
+		jsr  MOVMF
+		ldx  P8ZP_SCRATCH_REG_X
+		rts
+		.pend
+
+
+pop_2_floats_f2_in_fac1	.proc
+		; -- pop 2 floats from stack, load the second one in FAC1 as well
+		lda  #<fmath_float2
+		ldy  #>fmath_float2
+		jsr  pop_float
+		lda  #<fmath_float1
+		ldy  #>fmath_float1
+		jsr  pop_float
+		lda  #<fmath_float2
+		ldy  #>fmath_float2
+		jmp  MOVFM
+		.pend
+
+
+fmath_float1	.byte 0,0,0,0,0	; storage for a mflpt5 value
+fmath_float2	.byte 0,0,0,0,0	; storage for a mflpt5 value
+
+push_fac1_as_result	.proc
+		; -- push the float in FAC1 onto the stack, and return from calculation
+		ldx  #<fmath_float1
+		ldy  #>fmath_float1
+		jsr  MOVMF
+		lda  #<fmath_float1
+		ldy  #>fmath_float1
+		ldx  P8ZP_SCRATCH_REG_X
+		jmp  push_float
+		.pend
+
+pow_f		.proc
+		; -- push f1 ** f2 on stack
+		lda  #<fmath_float2
+		ldy  #>fmath_float2
+		jsr  pop_float
+		lda  #<fmath_float1
+		ldy  #>fmath_float1
+		jsr  pop_float
+		stx  P8ZP_SCRATCH_REG_X
+		lda  #<fmath_float1
+		ldy  #>fmath_float1
+		jsr  CONUPK		; fac2 = float1
+		lda  #<fmath_float2
+		ldy  #>fmath_float2
+		jsr  FPWR
+		ldx  P8ZP_SCRATCH_REG_X
+		jmp  push_fac1_as_result
+		.pend
+
+div_f		.proc
+		; -- push f1/f2 on stack
+		jsr  pop_2_floats_f2_in_fac1
+		stx  P8ZP_SCRATCH_REG_X
+		lda  #<fmath_float1
+		ldy  #>fmath_float1
+		jsr  FDIV
+		jmp  push_fac1_as_result
+		.pend
+
+add_f		.proc
+		; -- push f1+f2 on stack
+		jsr  pop_2_floats_f2_in_fac1
+		stx  P8ZP_SCRATCH_REG_X
+		lda  #<fmath_float1
+		ldy  #>fmath_float1
+		jsr  FADD
+		jmp  push_fac1_as_result
+		.pend
+
+sub_f		.proc
+		; -- push f1-f2 on stack
+		jsr  pop_2_floats_f2_in_fac1
+		stx  P8ZP_SCRATCH_REG_X
+		lda  #<fmath_float1
+		ldy  #>fmath_float1
+		jsr  FSUB
+		jmp  push_fac1_as_result
+		.pend
+
+mul_f		.proc
+		; -- push f1*f2 on stack
+		jsr  pop_2_floats_f2_in_fac1
+		stx  P8ZP_SCRATCH_REG_X
+		lda  #<fmath_float1
+		ldy  #>fmath_float1
+		jsr  FMULT
+		jmp  push_fac1_as_result
+		.pend
+
+neg_f		.proc
+		; -- push -flt back on stack
+		jsr  pop_float_fac1
+		stx  P8ZP_SCRATCH_REG_X
+		jsr  NEGOP
+		jmp  push_fac1_as_result
+		.pend
+
+abs_f		.proc
+		; -- push abs(float) on stack (as float)
+		jsr  pop_float_fac1
+		stx  P8ZP_SCRATCH_REG_X
+		jsr  ABS
+		jmp  push_fac1_as_result
+		.pend
+
+equal_f		.proc
+		; -- are the two mflpt5 numbers on the stack identical?
+		inx
+		inx
+		inx
+		inx
+		lda  P8ESTACK_LO-3,x
+		cmp  P8ESTACK_LO,x
+		bne  _equals_false
+		lda  P8ESTACK_LO-2,x
+		cmp  P8ESTACK_LO+1,x
+		bne  _equals_false
+		lda  P8ESTACK_LO-1,x
+		cmp  P8ESTACK_LO+2,x
+		bne  _equals_false
+		lda  P8ESTACK_HI-2,x
+		cmp  P8ESTACK_HI+1,x
+		bne  _equals_false
+		lda  P8ESTACK_HI-1,x
+		cmp  P8ESTACK_HI+2,x
+		bne  _equals_false
+_equals_true	lda  #1
+_equals_store	inx
+		sta  P8ESTACK_LO+1,x
+		rts
+_equals_false	lda  #0
+		beq  _equals_store
+		.pend
+
+notequal_f	.proc
+		; -- are the two mflpt5 numbers on the stack different?
+		jsr  equal_f
+		eor  #1		; invert the result
+		sta  P8ESTACK_LO+1,x
+		rts
+		.pend
+
+less_f		.proc
+		; -- is f1 < f2?
+		jsr  compare_floats
+		cmp  #255
+		beq  compare_floats._return_true
+		bne  compare_floats._return_false
+		.pend
+
+
+lesseq_f	.proc
+		; -- is f1 <= f2?
+		jsr  compare_floats
+		cmp  #255
+		beq  compare_floats._return_true
+		cmp  #0
+		beq  compare_floats._return_true
+		bne  compare_floats._return_false
+		.pend
+
+greater_f	.proc
+		; -- is f1 > f2?
+		jsr  compare_floats
+		cmp  #1
+		beq  compare_floats._return_true
+		bne  compare_floats._return_false
+		.pend
+
+greatereq_f	.proc
+		; -- is f1 >= f2?
+		jsr  compare_floats
+		cmp  #1
+		beq  compare_floats._return_true
+		cmp  #0
+		beq  compare_floats._return_true
+		bne  compare_floats._return_false
+		.pend
+
+compare_floats	.proc
+		lda  #<fmath_float2
+		ldy  #>fmath_float2
+		jsr  pop_float
+		lda  #<fmath_float1
+		ldy  #>fmath_float1
+		jsr  pop_float
+		lda  #<fmath_float1
+		ldy  #>fmath_float1
+		jsr  MOVFM		; fac1 = flt1
+		lda  #<fmath_float2
+		ldy  #>fmath_float2
+		stx  P8ZP_SCRATCH_REG
+		jsr  FCOMP		; A = flt1 compared with flt2 (0=equal, 1=flt1>flt2, 255=flt1<flt2)
+		ldx  P8ZP_SCRATCH_REG
+		rts
+_return_false	lda  #0
+_return_result  sta  P8ESTACK_LO,x
+		dex
+		rts
+_return_true	lda  #1
+		bne  _return_result
+		.pend
+
+func_sin	.proc
+		; -- push sin(f) back onto stack
+		jsr  pop_float_fac1
+		stx  P8ZP_SCRATCH_REG_X
+		jsr  SIN
+		jmp  push_fac1_as_result
+		.pend
+
+func_cos	.proc
+		; -- push cos(f) back onto stack
+		jsr  pop_float_fac1
+		stx  P8ZP_SCRATCH_REG_X
+		jsr  COS
+		jmp  push_fac1_as_result
+		.pend
+
+func_tan	.proc
+		; -- push tan(f) back onto stack
+		jsr  pop_float_fac1
+		stx  P8ZP_SCRATCH_REG_X
+		jsr  TAN
+		jmp  push_fac1_as_result
+		.pend
+
+func_atan	.proc
+		; -- push atan(f) back onto stack
+		jsr  pop_float_fac1
+		stx  P8ZP_SCRATCH_REG_X
+		jsr  ATN
+		jmp  push_fac1_as_result
+		.pend
+
+func_ln		.proc
+		; -- push ln(f) back onto stack
+		jsr  pop_float_fac1
+		stx  P8ZP_SCRATCH_REG_X
+		jsr  LOG
+		jmp  push_fac1_as_result
+		.pend
+
+func_log2	.proc
+		; -- push log base 2, ln(f)/ln(2), back onto stack
+		jsr  pop_float_fac1
+		stx  P8ZP_SCRATCH_REG_X
+		jsr  LOG
+		jsr  MOVEF
+		lda  #<c64.FL_LOG2
+		ldy  #>c64.FL_LOG2
+		jsr  MOVFM
+		jsr  FDIVT
+		jmp  push_fac1_as_result
+		.pend
+
+func_sqrt	.proc
+		jsr  pop_float_fac1
+		stx  P8ZP_SCRATCH_REG_X
+		jsr  SQR
+		jmp  push_fac1_as_result
+		.pend
+
+func_rad	.proc
+		; -- convert degrees to radians (d * pi / 180)
+		jsr  pop_float_fac1
+		stx  P8ZP_SCRATCH_REG_X
+		lda  #<_pi_div_180
+		ldy  #>_pi_div_180
+		jsr  FMULT
+		jmp  push_fac1_as_result
+_pi_div_180	.byte 123, 14, 250, 53, 18		; pi / 180
+		.pend
+
+func_deg	.proc
+		; -- convert radians to degrees (d * (1/ pi * 180))
+		jsr  pop_float_fac1
+		stx  P8ZP_SCRATCH_REG_X
+		lda  #<_one_over_pi_div_180
+		ldy  #>_one_over_pi_div_180
+		jsr  FMULT
+		jmp  push_fac1_as_result
+_one_over_pi_div_180	.byte 134, 101, 46, 224, 211		; 1 / (pi * 180)
+		.pend
+
+func_round	.proc
+		jsr  pop_float_fac1
+		stx  P8ZP_SCRATCH_REG_X
+		jsr  FADDH
+		jsr  INT
+		jmp  push_fac1_as_result
+		.pend
+
+func_floor	.proc
+		jsr  pop_float_fac1
+		stx  P8ZP_SCRATCH_REG_X
+		jsr  INT
+		jmp  push_fac1_as_result
+		.pend
+
+func_ceil	.proc
+		; -- ceil: tr = int(f); if tr==f -> return  else return tr+1
+		jsr  pop_float_fac1
+		stx  P8ZP_SCRATCH_REG_X
+		ldx  #<fmath_float1
+		ldy  #>fmath_float1
+		jsr  MOVMF
+		jsr  INT
+		lda  #<fmath_float1
+		ldy  #>fmath_float1
+		jsr  FCOMP
+		cmp  #0
+		beq  +
+		lda  #<FL_FONE
+		ldy  #>FL_FONE
+		jsr  FADD
++		jmp  push_fac1_as_result
+		.pend
+
+func_any_f	.proc
+		inx
+		lda  P8ESTACK_LO,x	; array size
+		sta  P8ZP_SCRATCH_B1
+		asl  a
+		asl  a
+		clc
+		adc  P8ZP_SCRATCH_B1	; times 5 because of float
+		jmp  prog8_lib.func_any_b._entry
+		.pend
+
+func_all_f	.proc
+		inx
+		jsr  prog8_lib.peek_address
+		lda  P8ESTACK_LO,x	; array size
+		sta  P8ZP_SCRATCH_B1
+		asl  a
+		asl  a
+		clc
+		adc  P8ZP_SCRATCH_B1	; times 5 because of float
+		tay
+		dey
+-		lda  (P8ZP_SCRATCH_W1),y
+		clc
+		dey
+		adc  (P8ZP_SCRATCH_W1),y
+		dey
+		adc  (P8ZP_SCRATCH_W1),y
+		dey
+		adc  (P8ZP_SCRATCH_W1),y
+		dey
+		adc  (P8ZP_SCRATCH_W1),y
+		dey
+		cmp  #0
+		beq  +
+		cpy  #255
+        	bne  -
+		lda  #1
+		sta  P8ESTACK_LO+1,x
+		rts
++		sta  P8ESTACK_LO+1,x
+		rts
+		.pend
+
+func_max_f	.proc
+		lda  #255
+		sta  _minmax_cmp+1
+		lda  #<_largest_neg_float
+		ldy  #>_largest_neg_float
+_minmax_entry	jsr  MOVFM
+		jsr  prog8_lib.pop_array_and_lengthmin1Y
+		stx  P8ZP_SCRATCH_REG_X
+-		sty  P8ZP_SCRATCH_REG
+		lda  P8ZP_SCRATCH_W1
+		ldy  P8ZP_SCRATCH_W1+1
+		jsr  FCOMP
+_minmax_cmp	cmp  #255			; modified
+		bne  +
+		lda  P8ZP_SCRATCH_W1
+		ldy  P8ZP_SCRATCH_W1+1
+		jsr  MOVFM
++		lda  P8ZP_SCRATCH_W1
+		clc
+		adc  #5
+		sta  P8ZP_SCRATCH_W1
+		bcc  +
+		inc  P8ZP_SCRATCH_W1+1
++		ldy  P8ZP_SCRATCH_REG
+		dey
+		cpy  #255
+		bne  -
+		jmp  push_fac1_as_result
+_largest_neg_float	.byte 255,255,255,255,255		; largest negative float -1.7014118345e+38
+		.pend
+
+func_min_f	.proc
+		lda  #1
+		sta  func_max_f._minmax_cmp+1
+		lda  #<_largest_pos_float
+		ldy  #>_largest_pos_float
+		jmp  func_max_f._minmax_entry
+_largest_pos_float	.byte  255,127,255,255,255		; largest positive float
+		rts
+		.pend
+
+func_sum_f	.proc
+		lda  #<FL_ZERO
+		ldy  #>FL_ZERO
+		jsr  MOVFM
+		jsr  prog8_lib.pop_array_and_lengthmin1Y
+		stx  P8ZP_SCRATCH_REG_X
+-		sty  P8ZP_SCRATCH_REG
+		lda  P8ZP_SCRATCH_W1
+		ldy  P8ZP_SCRATCH_W1+1
+		jsr  FADD
+		ldy  P8ZP_SCRATCH_REG
+		dey
+		cpy  #255
+		beq  +
+		lda  P8ZP_SCRATCH_W1
+		clc
+		adc  #5
+		sta  P8ZP_SCRATCH_W1
+		bcc  -
+		inc  P8ZP_SCRATCH_W1+1
+		bne  -
++		jmp  push_fac1_as_result
+		.pend
+
+sign_f		.proc
+		jsr  pop_float_fac1
+		jsr  SIGN
+		sta  P8ESTACK_LO,x
+		dex
+		rts
+		.pend
+
+
+set_0_array_float	.proc
+		; -- set a float in an array to zero (index on stack, array in SCRATCH_ZPWORD1)
+		inx
+		lda  P8ESTACK_LO,x
+		asl  a
+		asl  a
+		clc
+		adc  P8ESTACK_LO,x
+		tay
+		lda  #0
+		sta  (P8ZP_SCRATCH_W1),y
+		iny
+		sta  (P8ZP_SCRATCH_W1),y
+		iny
+		sta  (P8ZP_SCRATCH_W1),y
+		iny
+		sta  (P8ZP_SCRATCH_W1),y
+		iny
+		sta  (P8ZP_SCRATCH_W1),y
+		rts
+		.pend
+
+
+set_array_float		.proc
+		; -- set a float in an array to a value (index on stack, float in SCRATCH_ZPWORD1, array in SCRATCH_ZPWORD2)
+		inx
+		lda  P8ESTACK_LO,x
+		asl  a
+		asl  a
+		clc
+		adc  P8ESTACK_LO,x
+		adc  P8ZP_SCRATCH_W2
+		ldy  P8ZP_SCRATCH_W2+1
+		bcc  +
+		iny
++		jmp  copy_float
+			; -- copies the 5 bytes of the mflt value pointed to by SCRATCH_ZPWORD1,
+			;    into the 5 bytes pointed to by A/Y.  Clobbers A,Y.
+		.pend
+
+
+swap_floats	.proc
+		; -- swap floats pointed to by SCRATCH_ZPWORD1, SCRATCH_ZPWORD2
+		ldy  #4
+-               lda  (P8ZP_SCRATCH_W1),y
+		pha
+		lda  (P8ZP_SCRATCH_W2),y
+		sta  (P8ZP_SCRATCH_W1),y
+		pla
+		sta  (P8ZP_SCRATCH_W2),y
+		dey
+		bpl  -
+		rts
+		.pend

compiler/res/prog8lib/c64lib.p8

@@ -6,238 +6,427 @@
 ; indent format: TABS, size=8
 
 
-~ c64 {
+c64 {
-		memory  ubyte  SCRATCH_ZPB1	= $02		; scratch byte 1 in ZP
+        &ubyte  TIME_HI         = $a0       ; software jiffy clock, hi byte
-		memory  ubyte  SCRATCH_ZPREG	= $03		; scratch register in ZP
+        &ubyte  TIME_MID        = $a1       ;  .. mid byte
-		memory  ubyte  SCRATCH_ZPREGX	= $fa		; temp storage for X register (stack pointer)
+        &ubyte  TIME_LO         = $a2       ;    .. lo byte. Updated by IRQ every 1/60 sec
-		memory  uword  SCRATCH_ZPWORD1	= $fb		; scratch word in ZP ($fb/$fc)
+        &ubyte  STKEY           = $91       ; various keyboard statuses (updated by IRQ)
-		memory  uword  SCRATCH_ZPWORD2	= $fd		; scratch word in ZP ($fd/$fe)
+        &ubyte  SFDX            = $cb       ; current key pressed (matrix value) (updated by IRQ)
-		const   uword  ESTACK_LO	= $ce00		; evaluation stack (lsb)
-		const   uword  ESTACK_HI	= $cf00		; evaluation stack (msb)
 
+        &ubyte  COLOR           = $0286     ; cursor color
+        &ubyte  HIBASE          = $0288     ; screen base address / 256 (hi-byte of screen memory address)
+        &uword  CINV            = $0314     ; IRQ vector
+        &uword  NMI_VEC         = $FFFA     ; 6502 nmi vector, determined by the kernal if banked in
+        &uword  RESET_VEC       = $FFFC     ; 6502 reset vector, determined by the kernal if banked in
+        &uword  IRQ_VEC         = $FFFE     ; 6502 interrupt vector, determined by the kernal if banked in
 
-		memory  ubyte  TIME_HI		= $a0		; software jiffy clock, hi byte
+        ; the default addresses for the character screen chars and colors
-		memory  ubyte  TIME_MID		= $a1		;  .. mid byte
+        const  uword  Screen    = $0400     ; to have this as an array[40*25] the compiler would have to support array size > 255
-		memory  ubyte  TIME_LO		= $a2		;    .. lo byte. Updated by IRQ every 1/60 sec
+        const  uword  Colors    = $d800     ; to have this as an array[40*25] the compiler would have to support array size > 255
-		memory  ubyte  STKEY		= $91		; various keyboard statuses (updated by IRQ)
-		memory  ubyte  SFDX		= $cb		; current key pressed (matrix value) (updated by IRQ)
 
-		memory  ubyte  COLOR		= $0286		; cursor color
+        ; the default locations of the 8 sprite pointers (store address of sprite / 64)
-		memory  ubyte  HIBASE		= $0288		; screen base address / 256 (hi-byte of screen memory address)
+        &ubyte  SPRPTR0         = 2040
-		memory  uword  CINV		= $0314		; IRQ vector
+        &ubyte  SPRPTR1         = 2041
-		memory  uword  NMI_VEC		= $FFFA		; 6502 nmi vector, determined by the kernal if banked in
+        &ubyte  SPRPTR2         = 2042
-		memory  uword  RESET_VEC	= $FFFC		; 6502 reset vector, determined by the kernal if banked in
+        &ubyte  SPRPTR3         = 2043
-		memory  uword  IRQ_VEC		= $FFFE		; 6502 interrupt vector, determined by the kernal if banked in
+        &ubyte  SPRPTR4         = 2044
+        &ubyte  SPRPTR5         = 2045
+        &ubyte  SPRPTR6         = 2046
+        &ubyte  SPRPTR7         = 2047
+        &ubyte[8]  SPRPTR       = 2040      ; the 8 sprite pointers as an array.
 
-		; the default addresses for the character screen chars and colors
-		const   uword  Screen		= $0400		; to have this as an array[40*25] the compiler would have to support array size > 255
-		const   uword  Colors		= $d800		; to have this as an array[40*25] the compiler would have to support array size > 255
-
-		; the default locations of the 8 sprite pointers (store address of sprite / 64)
-		memory  ubyte  SPRPTR0		= 2040
-		memory  ubyte  SPRPTR1		= 2041
-		memory  ubyte  SPRPTR2		= 2042
-		memory  ubyte  SPRPTR3		= 2043
-		memory  ubyte  SPRPTR4		= 2044
-		memory  ubyte  SPRPTR5		= 2045
-		memory  ubyte  SPRPTR6		= 2046
-		memory  ubyte  SPRPTR7		= 2047
-		memory  ubyte[8]  SPRPTR	= 2040		; the 8 sprite pointers as an array.
- 
 
 ; ---- VIC-II 6567/6569/856x registers ----
 
-		memory  ubyte  SP0X		= $d000
+        &ubyte  SP0X            = $d000
-		memory  ubyte  SP0Y		= $d001
+        &ubyte  SP0Y            = $d001
-		memory  ubyte  SP1X		= $d002
+        &ubyte  SP1X            = $d002
-		memory  ubyte  SP1Y		= $d003
+        &ubyte  SP1Y            = $d003
-		memory  ubyte  SP2X		= $d004
+        &ubyte  SP2X            = $d004
-		memory  ubyte  SP2Y		= $d005
+        &ubyte  SP2Y            = $d005
-		memory  ubyte  SP3X		= $d006
+        &ubyte  SP3X            = $d006
-		memory  ubyte  SP3Y		= $d007
+        &ubyte  SP3Y            = $d007
-		memory  ubyte  SP4X		= $d008
+        &ubyte  SP4X            = $d008
-		memory  ubyte  SP4Y		= $d009
+        &ubyte  SP4Y            = $d009
-		memory  ubyte  SP5X		= $d00a
+        &ubyte  SP5X            = $d00a
-		memory  ubyte  SP5Y		= $d00b
+        &ubyte  SP5Y            = $d00b
-		memory  ubyte  SP6X		= $d00c
+        &ubyte  SP6X            = $d00c
-		memory  ubyte  SP6Y		= $d00d
+        &ubyte  SP6Y            = $d00d
-		memory  ubyte  SP7X		= $d00e
+        &ubyte  SP7X            = $d00e
-		memory  ubyte  SP7Y		= $d00f
+        &ubyte  SP7Y            = $d00f
-		memory  ubyte[16]  SPXY		= $d000		; the 8 sprite X and Y registers as an array.
+        &ubyte[16]  SPXY        = $d000        ; the 8 sprite X and Y registers as an array.
-		memory  uword[8]  SPXYW		= $d000		; the 8 sprite X and Y registers as a combined xy word array.
+        &uword[8]  SPXYW        = $d000        ; the 8 sprite X and Y registers as a combined xy word array.
 
-		memory  ubyte  MSIGX		= $d010
+        &ubyte  MSIGX           = $d010
-		memory  ubyte  SCROLY		= $d011
+        &ubyte  SCROLY          = $d011
-		memory  ubyte  RASTER		= $d012
+        &ubyte  RASTER          = $d012
-		memory  ubyte  LPENX		= $d013
+        &ubyte  LPENX           = $d013
-		memory  ubyte  LPENY		= $d014
+        &ubyte  LPENY           = $d014
-		memory  ubyte  SPENA		= $d015
+        &ubyte  SPENA           = $d015
-		memory  ubyte  SCROLX		= $d016
+        &ubyte  SCROLX          = $d016
-		memory  ubyte  YXPAND		= $d017
+        &ubyte  YXPAND          = $d017
-		memory  ubyte  VMCSB		= $d018
+        &ubyte  VMCSB           = $d018
-		memory  ubyte  VICIRQ		= $d019
+        &ubyte  VICIRQ          = $d019
-		memory  ubyte  IREQMASK		= $d01a
+        &ubyte  IREQMASK        = $d01a
-		memory  ubyte  SPBGPR		= $d01b
+        &ubyte  SPBGPR          = $d01b
-		memory  ubyte  SPMC		= $d01c
+        &ubyte  SPMC            = $d01c
-		memory  ubyte  XXPAND		= $d01d
+        &ubyte  XXPAND          = $d01d
-		memory  ubyte  SPSPCL		= $d01e
+        &ubyte  SPSPCL          = $d01e
-		memory  ubyte  SPBGCL		= $d01f
+        &ubyte  SPBGCL          = $d01f
+
+        &ubyte  EXTCOL          = $d020        ; border color
+        &ubyte  BGCOL0          = $d021        ; screen color
+        &ubyte  BGCOL1          = $d022
+        &ubyte  BGCOL2          = $d023
+        &ubyte  BGCOL4          = $d024
+        &ubyte  SPMC0           = $d025
+        &ubyte  SPMC1           = $d026
+        &ubyte  SP0COL          = $d027
+        &ubyte  SP1COL          = $d028
+        &ubyte  SP2COL          = $d029
+        &ubyte  SP3COL          = $d02a
+        &ubyte  SP4COL          = $d02b
+        &ubyte  SP5COL          = $d02c
+        &ubyte  SP6COL          = $d02d
+        &ubyte  SP7COL          = $d02e
+        &ubyte[8]  SPCOL        = $d027
 
-		memory  ubyte  EXTCOL		= $d020		; border color
-		memory  ubyte  BGCOL0		= $d021		; screen color
-		memory  ubyte  BGCOL1		= $d022
-		memory  ubyte  BGCOL2		= $d023
-		memory  ubyte  BGCOL4		= $d024
-		memory  ubyte  SPMC0		= $d025
-		memory  ubyte  SPMC1		= $d026
-		memory  ubyte  SP0COL		= $d027
-		memory  ubyte  SP1COL		= $d028
-		memory  ubyte  SP2COL		= $d029
-		memory  ubyte  SP3COL		= $d02a
-		memory  ubyte  SP4COL		= $d02b
-		memory  ubyte  SP5COL		= $d02c
-		memory  ubyte  SP6COL		= $d02d
-		memory  ubyte  SP7COL		= $d02e
-		memory  ubyte[8]  SPCOL		= $d027
-		
 
 ; ---- end of VIC-II registers ----
 
 ; ---- CIA 6526 1 & 2 registers ----
 
-		memory  ubyte  CIA1PRA		= $DC00		; CIA 1 DRA, keyboard column drive
+        &ubyte  CIA1PRA         = $DC00        ; CIA 1 DRA, keyboard column drive (and joystick control port #2)
-		memory  ubyte  CIA1PRB		= $DC01		; CIA 1 DRB, keyboard row port
+        &ubyte  CIA1PRB         = $DC01        ; CIA 1 DRB, keyboard row port (and joystick control port #1)
-		memory  ubyte  CIA1DDRA		= $DC02		; CIA 1 DDRA, keyboard column
+        &ubyte  CIA1DDRA        = $DC02        ; CIA 1 DDRA, keyboard column
-		memory  ubyte  CIA1DDRB		= $DC03		; CIA 1 DDRB, keyboard row
+        &ubyte  CIA1DDRB        = $DC03        ; CIA 1 DDRB, keyboard row
-		memory  ubyte  CIA1TAL		= $DC04		; CIA 1 timer A low byte
+        &ubyte  CIA1TAL         = $DC04        ; CIA 1 timer A low byte
-		memory  ubyte  CIA1TAH		= $DC05		; CIA 1 timer A high byte
+        &ubyte  CIA1TAH         = $DC05        ; CIA 1 timer A high byte
-		memory  ubyte  CIA1TBL		= $DC06		; CIA 1 timer B low byte
+        &ubyte  CIA1TBL         = $DC06        ; CIA 1 timer B low byte
-		memory  ubyte  CIA1TBH		= $DC07		; CIA 1 timer B high byte
+        &ubyte  CIA1TBH         = $DC07        ; CIA 1 timer B high byte
-		memory  ubyte  CIA1TOD10	= $DC08		; time of day, 1/10 sec.
+        &ubyte  CIA1TOD10       = $DC08        ; time of day, 1/10 sec.
-		memory  ubyte  CIA1TODSEC	= $DC09		; time of day, seconds
+        &ubyte  CIA1TODSEC      = $DC09        ; time of day, seconds
-		memory  ubyte  CIA1TODMMIN	= $DC0A		; time of day, minutes
+        &ubyte  CIA1TODMMIN     = $DC0A        ; time of day, minutes
-		memory  ubyte  CIA1TODHR	= $DC0B		; time of day, hours
+        &ubyte  CIA1TODHR       = $DC0B        ; time of day, hours
-		memory  ubyte  CIA1SDR		= $DC0C		; Serial Data Register
+        &ubyte  CIA1SDR         = $DC0C        ; Serial Data Register
-		memory  ubyte  CIA1ICR		= $DC0D
+        &ubyte  CIA1ICR         = $DC0D
-		memory  ubyte  CIA1CRA		= $DC0E
+        &ubyte  CIA1CRA         = $DC0E
-		memory  ubyte  CIA1CRB		= $DC0F
+        &ubyte  CIA1CRB         = $DC0F
 
-		memory  ubyte  CIA2PRA		= $DD00		; CIA 2 DRA, serial port and video address
+        &ubyte  CIA2PRA         = $DD00        ; CIA 2 DRA, serial port and video address
-		memory  ubyte  CIA2PRB		= $DD01		; CIA 2 DRB, RS232 port / USERPORT
+        &ubyte  CIA2PRB         = $DD01        ; CIA 2 DRB, RS232 port / USERPORT
-		memory  ubyte  CIA2DDRA		= $DD02		; CIA 2 DDRA, serial port and video address
+        &ubyte  CIA2DDRA        = $DD02        ; CIA 2 DDRA, serial port and video address
-		memory  ubyte  CIA2DDRB		= $DD03		; CIA 2 DDRB, RS232 port / USERPORT
+        &ubyte  CIA2DDRB        = $DD03        ; CIA 2 DDRB, RS232 port / USERPORT
-		memory  ubyte  CIA2TAL		= $DD04		; CIA 2 timer A low byte
+        &ubyte  CIA2TAL         = $DD04        ; CIA 2 timer A low byte
-		memory  ubyte  CIA2TAH		= $DD05		; CIA 2 timer A high byte
+        &ubyte  CIA2TAH         = $DD05        ; CIA 2 timer A high byte
-		memory  ubyte  CIA2TBL		= $DD06		; CIA 2 timer B low byte
+        &ubyte  CIA2TBL         = $DD06        ; CIA 2 timer B low byte
-		memory  ubyte  CIA2TBH		= $DD07		; CIA 2 timer B high byte
+        &ubyte  CIA2TBH         = $DD07        ; CIA 2 timer B high byte
-		memory  ubyte  CIA2TOD10	= $DD08		; time of day, 1/10 sec.
+        &ubyte  CIA2TOD10       = $DD08        ; time of day, 1/10 sec.
-		memory  ubyte  CIA2TODSEC	= $DD09		; time of day, seconds
+        &ubyte  CIA2TODSEC      = $DD09        ; time of day, seconds
-		memory  ubyte  CIA2TODMIN	= $DD0A		; time of day, minutes
+        &ubyte  CIA2TODMIN      = $DD0A        ; time of day, minutes
-		memory  ubyte  CIA2TODHR	= $DD0B		; time of day, hours
+        &ubyte  CIA2TODHR       = $DD0B        ; time of day, hours
-		memory  ubyte  CIA2SDR		= $DD0C		; Serial Data Register
+        &ubyte  CIA2SDR         = $DD0C        ; Serial Data Register
-		memory  ubyte  CIA2ICR		= $DD0D
+        &ubyte  CIA2ICR         = $DD0D
-		memory  ubyte  CIA2CRA		= $DD0E
+        &ubyte  CIA2CRA         = $DD0E
-		memory  ubyte  CIA2CRB		= $DD0F
+        &ubyte  CIA2CRB         = $DD0F
 
 ; ---- end of CIA registers ----
 
 ; ---- SID 6581/8580 registers ----
 
-		memory  ubyte  FREQLO1		= $D400		; channel 1 freq lo
+        &ubyte  FREQLO1         = $D400        ; channel 1 freq lo
-		memory	ubyte  FREQHI1		= $D401		; channel 1 freq hi
+        &ubyte  FREQHI1         = $D401        ; channel 1 freq hi
-		memory  uword  FREQ1		= $D400		; channel 1 freq (word)
+        &uword  FREQ1           = $D400        ; channel 1 freq (word)
-		memory  ubyte  PWLO1		= $D402		; channel 1 pulse width lo (7-0)
+        &ubyte  PWLO1           = $D402        ; channel 1 pulse width lo (7-0)
-		memory  ubyte  PWHI1		= $D403		; channel 1 pulse width hi (11-8)
+        &ubyte  PWHI1           = $D403        ; channel 1 pulse width hi (11-8)
-		memory  uword  PW1		= $D402		; channel 1 pulse width (word)
+        &uword  PW1             = $D402        ; channel 1 pulse width (word)
-		memory  ubyte  CR1		= $D404		; channel 1 voice control register
+        &ubyte  CR1             = $D404        ; channel 1 voice control register
-		memory  ubyte  AD1		= $D405		; channel 1 attack & decay
+        &ubyte  AD1             = $D405        ; channel 1 attack & decay
-		memory  ubyte  SR1		= $D406		; channel 1 sustain & release
+        &ubyte  SR1             = $D406        ; channel 1 sustain & release
-		memory  ubyte  FREQLO2		= $D407		; channel 2 freq lo
+        &ubyte  FREQLO2         = $D407        ; channel 2 freq lo
-		memory	ubyte  FREQHI2		= $D408		; channel 2 freq hi
+        &ubyte  FREQHI2         = $D408        ; channel 2 freq hi
-		memory  uword  FREQ2		= $D407		; channel 2 freq (word)
+        &uword  FREQ2           = $D407        ; channel 2 freq (word)
-		memory  ubyte  PWLO2		= $D409		; channel 2 pulse width lo (7-0)
+        &ubyte  PWLO2           = $D409        ; channel 2 pulse width lo (7-0)
-		memory  ubyte  PWHI2		= $D40A		; channel 2 pulse width hi (11-8)
+        &ubyte  PWHI2           = $D40A        ; channel 2 pulse width hi (11-8)
-		memory  uword  PW2		= $D409		; channel 2 pulse width (word)
+        &uword  PW2             = $D409        ; channel 2 pulse width (word)
-		memory  ubyte  CR2		= $D40B		; channel 2 voice control register
+        &ubyte  CR2             = $D40B        ; channel 2 voice control register
-		memory  ubyte  AD2		= $D40C		; channel 2 attack & decay
+        &ubyte  AD2             = $D40C        ; channel 2 attack & decay
-		memory  ubyte  SR2		= $D40D		; channel 2 sustain & release
+        &ubyte  SR2             = $D40D        ; channel 2 sustain & release
-		memory  ubyte  FREQLO3		= $D40E		; channel 3 freq lo
+        &ubyte  FREQLO3         = $D40E        ; channel 3 freq lo
-		memory	ubyte  FREQHI3		= $D40F		; channel 3 freq hi
+        &ubyte  FREQHI3         = $D40F        ; channel 3 freq hi
-		memory  uword  FREQ3		= $D40E		; channel 3 freq (word)
+        &uword  FREQ3           = $D40E        ; channel 3 freq (word)
-		memory  ubyte  PWLO3		= $D410		; channel 3 pulse width lo (7-0)
+        &ubyte  PWLO3           = $D410        ; channel 3 pulse width lo (7-0)
-		memory  ubyte  PWHI3		= $D411		; channel 3 pulse width hi (11-8)
+        &ubyte  PWHI3           = $D411        ; channel 3 pulse width hi (11-8)
-		memory  uword  PW3		= $D410		; channel 3 pulse width (word)
+        &uword  PW3             = $D410        ; channel 3 pulse width (word)
-		memory  ubyte  CR3		= $D412		; channel 3 voice control register
+        &ubyte  CR3             = $D412        ; channel 3 voice control register
-		memory  ubyte  AD3		= $D413		; channel 3 attack & decay
+        &ubyte  AD3             = $D413        ; channel 3 attack & decay
-		memory  ubyte  SR3		= $D414		; channel 3 sustain & release
+        &ubyte  SR3             = $D414        ; channel 3 sustain & release
-		memory  ubyte  FCLO		= $D415		; filter cutoff lo (2-0)
+        &ubyte  FCLO            = $D415        ; filter cutoff lo (2-0)
-		memory  ubyte  FCHI		= $D416		; filter cutoff hi (10-3)
+        &ubyte  FCHI            = $D416        ; filter cutoff hi (10-3)
-		memory  uword  FC		= $D415		; filter cutoff (word)
+        &uword  FC              = $D415        ; filter cutoff (word)
-		memory  ubyte  RESFILT		= $D417		; filter resonance and routing
+        &ubyte  RESFILT         = $D417        ; filter resonance and routing
-		memory  ubyte  MVOL		= $D418		; filter mode and main volume control
+        &ubyte  MVOL            = $D418        ; filter mode and main volume control
-		memory  ubyte  POTX		= $D419		; potentiometer X
+        &ubyte  POTX            = $D419        ; potentiometer X
-		memory  ubyte  POTY		= $D41A		; potentiometer Y
+        &ubyte  POTY            = $D41A        ; potentiometer Y
-		memory  ubyte  OSC3		= $D41B		; channel 3 oscillator value read
+        &ubyte  OSC3            = $D41B        ; channel 3 oscillator value read
-		memory  ubyte  ENV3		= $D41C		; channel 3 envelope value read
+        &ubyte  ENV3            = $D41C        ; channel 3 envelope value read
 
 ; ---- end of SID registers ----
 
 
+; ---- C64 ROM kernal routines ----
 
-; ---- C64 basic routines ----
+romsub $AB1E = STROUT(uword strptr @ AY) clobbers(A, X, Y)      ; print null-terminated string (use c64scr.print instead)
+romsub $E544 = CLEARSCR() clobbers(A,X,Y)                       ; clear the screen
+romsub $E566 = HOMECRSR() clobbers(A,X,Y)                       ; cursor to top left of screen
+romsub $EA31 = IRQDFRT() clobbers(A,X,Y)                        ; default IRQ routine
+romsub $EA81 = IRQDFEND() clobbers(A,X,Y)                       ; default IRQ end/cleanup
+romsub $FF81 = CINT() clobbers(A,X,Y)                           ; (alias: SCINIT) initialize screen editor and video chip
+romsub $FF84 = IOINIT() clobbers(A, X)                          ; initialize I/O devices (CIA, SID, IRQ)
+romsub $FF87 = RAMTAS() clobbers(A,X,Y)                         ; initialize RAM, tape buffer, screen
+romsub $FF8A = RESTOR() clobbers(A,X,Y)                         ; restore default I/O vectors
+romsub $FF8D = VECTOR(uword userptr @ XY, ubyte dir @ Pc) clobbers(A,Y)     ; read/set I/O vector table
+romsub $FF90 = SETMSG(ubyte value @ A)                          ; set Kernal message control flag
+romsub $FF93 = SECOND(ubyte address @ A) clobbers(A)            ; (alias: LSTNSA) send secondary address after LISTEN
+romsub $FF96 = TKSA(ubyte address @ A) clobbers(A)              ; (alias: TALKSA) send secondary address after TALK
+romsub $FF99 = MEMTOP(uword address @ XY, ubyte dir @ Pc) -> uword @ XY     ; read/set top of memory  pointer
+romsub $FF9C = MEMBOT(uword address @ XY, ubyte dir @ Pc) -> uword @ XY     ; read/set bottom of memory  pointer
+romsub $FF9F = SCNKEY() clobbers(A,X,Y)                         ; scan the keyboard
+romsub $FFA2 = SETTMO(ubyte timeout @ A)                        ; set time-out flag for IEEE bus
+romsub $FFA5 = ACPTR() -> ubyte @ A                             ; (alias: IECIN) input byte from serial bus
+romsub $FFA8 = CIOUT(ubyte databyte @ A)                        ; (alias: IECOUT) output byte to serial bus
+romsub $FFAB = UNTLK() clobbers(A)                              ; command serial bus device to UNTALK
+romsub $FFAE = UNLSN() clobbers(A)                              ; command serial bus device to UNLISTEN
+romsub $FFB1 = LISTEN(ubyte device @ A) clobbers(A)             ; command serial bus device to LISTEN
+romsub $FFB4 = TALK(ubyte device @ A) clobbers(A)               ; command serial bus device to TALK
+romsub $FFB7 = READST() -> ubyte @ A                            ; read I/O status word
+romsub $FFBA = SETLFS(ubyte logical @ A, ubyte device @ X, ubyte address @ Y)   ; set logical file parameters
+romsub $FFBD = SETNAM(ubyte namelen @ A, str filename @ XY)     ; set filename parameters
+romsub $FFC0 = OPEN() clobbers(A,X,Y)                           ; (via 794 ($31A)) open a logical file
+romsub $FFC3 = CLOSE(ubyte logical @ A) clobbers(A,X,Y)         ; (via 796 ($31C)) close a logical file
+romsub $FFC6 = CHKIN(ubyte logical @ X) clobbers(A,X)           ; (via 798 ($31E)) define an input channel
+romsub $FFC9 = CHKOUT(ubyte logical @ X) clobbers(A,X)          ; (via 800 ($320)) define an output channel
+romsub $FFCC = CLRCHN() clobbers(A,X)                           ; (via 802 ($322)) restore default devices
+romsub $FFCF = CHRIN() clobbers(Y) -> ubyte @ A                 ; (via 804 ($324)) input a character (for keyboard, read a whole line from the screen) A=byte read.
+romsub $FFD2 = CHROUT(ubyte char @ A)                           ; (via 806 ($326)) output a character
+romsub $FFD5 = LOAD(ubyte verify @ A, uword address @ XY) -> ubyte @Pc, ubyte @ A, ubyte @ X, ubyte @ Y     ; (via 816 ($330)) load from device
+romsub $FFD8 = SAVE(ubyte zp_startaddr @ A, uword endaddr @ XY) -> ubyte @ Pc, ubyte @ A                    ; (via 818 ($332)) save to a device
+romsub $FFDB = SETTIM(ubyte low @ A, ubyte middle @ X, ubyte high @ Y)      ; set the software clock
+romsub $FFDE = RDTIM() -> ubyte @ A, ubyte @ X, ubyte @ Y       ; read the software clock
+romsub $FFE1 = STOP() clobbers(A,X) -> ubyte @ Pz, ubyte @ Pc   ; (via 808 ($328)) check the STOP key
+romsub $FFE4 = GETIN() clobbers(X,Y) -> ubyte @ A               ; (via 810 ($32A)) get a character
+romsub $FFE7 = CLALL() clobbers(A,X)                            ; (via 812 ($32C)) close all files
+romsub $FFEA = UDTIM() clobbers(A,X)                            ; update the software clock
+romsub $FFED = SCREEN() -> ubyte @ X, ubyte @ Y                 ; read number of screen rows and columns
+romsub $FFF0 = PLOT(ubyte col @ Y, ubyte row @ X, ubyte dir @ Pc) -> ubyte @ X, ubyte @ Y       ; read/set position of cursor on screen.  Use c64scr.plot for a 'safe' wrapper that preserves X.
+romsub $FFF3 = IOBASE() -> uword @ XY                           ; read base address of I/O devices
 
-asmsub	CLEARSCR	() -> clobbers(A,X,Y) -> ()		= $E544		; clear the screen
+; ---- end of C64 ROM kernal routines ----
-asmsub	HOMECRSR	() -> clobbers(A,X,Y) -> ()		= $E566		; cursor to top left of screen
 
 
-; ---- end of C64 basic routines ----
+; ---- C64 specific system utility routines: ----
 
+asmsub  init_system()  {
+    ; Initializes the machine to a sane starting state.
+    ; Called automatically by the loader program logic.
+    ; This means that the BASIC, KERNAL and CHARGEN ROMs are banked in,
+    ; the VIC, SID and CIA chips are reset, screen is cleared, and the default IRQ is set.
+    ; Also a different color scheme is chosen to identify ourselves a little.
+    ; Uppercase charset is activated, and all three registers set to 0, status flags cleared.
+    %asm {{
+        sei
+        cld
+        lda  #%00101111
+        sta  $00
+        lda  #%00100111
+        sta  $01
+        jsr  c64.IOINIT
+        jsr  c64.RESTOR
+        jsr  c64.CINT
+        lda  #6
+        sta  c64.EXTCOL
+        lda  #7
+        sta  c64.COLOR
+        lda  #0
+        sta  c64.BGCOL0
+        tax
+        tay
+        clc
+        clv
+        cli
+        rts
+    }}
+}
 
-; ---- C64 kernal routines ----
+asmsub  set_irqvec_excl() clobbers(A)  {
+	%asm {{
+		sei
+		lda  #<_irq_handler
+		sta  c64.CINV
+		lda  #>_irq_handler
+		sta  c64.CINV+1
+		cli
+		rts
+_irq_handler	jsr  set_irqvec._irq_handler_init
+		jsr  irq.irq
+		jsr  set_irqvec._irq_handler_end
+		lda  #$ff
+		sta  c64.VICIRQ			; acknowledge raster irq
+		lda  c64.CIA1ICR		; acknowledge CIA1 interrupt
+		jmp  c64.IRQDFEND		; end irq processing - don't call kernel
+	}}
+}
 
-asmsub	STROUT   (uword strptr @ AY) -> clobbers(A, X, Y) -> ()	= $AB1E		; print null-terminated string (use c64scr.print instead)
+asmsub  set_irqvec() clobbers(A)  {
-asmsub	IRQDFRT  () -> clobbers(A,X,Y) -> ()			= $EA31		; default IRQ routine
+	%asm {{
-asmsub	IRQDFEND () -> clobbers(A,X,Y) -> ()			= $EA81		; default IRQ end/cleanup
+		sei
-asmsub	CINT     () -> clobbers(A,X,Y) -> ()			= $FF81		; (alias: SCINIT) initialize screen editor and video chip
+		lda  #<_irq_handler
-asmsub	IOINIT   () -> clobbers(A, X) -> ()			= $FF84		; initialize I/O devices (CIA, SID, IRQ)
+		sta  c64.CINV
-asmsub	RAMTAS   () -> clobbers(A,X,Y) -> ()			= $FF87		; initialize RAM, tape buffer, screen
+		lda  #>_irq_handler
-asmsub	RESTOR   () -> clobbers(A,X,Y) -> ()			= $FF8A		; restore default I/O vectors
+		sta  c64.CINV+1
-asmsub	VECTOR   (ubyte dir @ Pc, uword userptr @ XY) -> clobbers(A,Y) -> ()	= $FF8D		; read/set I/O vector table
+		cli
-asmsub	SETMSG   (ubyte value @ A) -> clobbers() -> ()		= $FF90		; set Kernal message control flag
+		rts
-asmsub	SECOND   (ubyte address @ A) -> clobbers(A) -> ()	= $FF93		; (alias: LSTNSA) send secondary address after LISTEN
+_irq_handler    jsr  _irq_handler_init
-asmsub	TKSA     (ubyte address @ A) -> clobbers(A) -> ()	= $FF96		; (alias: TALKSA) send secondary address after TALK
+		jsr  irq.irq
-asmsub	MEMTOP   (ubyte dir @ Pc, uword address @ XY) -> clobbers() -> (uword @ XY)	= $FF99		; read/set top of memory  pointer
+		jsr  _irq_handler_end
-asmsub	MEMBOT   (ubyte dir @ Pc, uword address @ XY) -> clobbers() -> (uword @ XY)	= $FF9C		; read/set bottom of memory  pointer
+		jmp  c64.IRQDFRT		; continue with normal kernel irq routine
-asmsub	SCNKEY   () -> clobbers(A,X,Y) -> ()			= $FF9F		; scan the keyboard
+
-asmsub	SETTMO   (ubyte timeout @ A) -> clobbers() -> ()	= $FFA2		; set time-out flag for IEEE bus
+_irq_handler_init
-asmsub	ACPTR    () -> clobbers() -> (ubyte @ A)			= $FFA5		; (alias: IECIN) input byte from serial bus
+		; save all zp scratch registers and the X register as these might be clobbered by the irq routine
-asmsub	CIOUT    (ubyte databyte @ A) -> clobbers() -> ()	= $FFA8		; (alias: IECOUT) output byte to serial bus
+		stx  IRQ_X_REG
-asmsub	UNTLK    () -> clobbers(A) -> ()			= $FFAB		; command serial bus device to UNTALK
+		lda  P8ZP_SCRATCH_B1
-asmsub	UNLSN    () -> clobbers(A) -> ()			= $FFAE		; command serial bus device to UNLISTEN
+		sta  IRQ_SCRATCH_ZPB1
-asmsub	LISTEN   (ubyte device @ A) -> clobbers(A) -> ()	= $FFB1		; command serial bus device to LISTEN
+		lda  P8ZP_SCRATCH_REG
-asmsub	TALK     (ubyte device @ A) -> clobbers(A) -> ()	= $FFB4		; command serial bus device to TALK
+		sta  IRQ_SCRATCH_ZPREG
-asmsub	READST   () -> clobbers() -> (ubyte @ A)			= $FFB7		; read I/O status word
+		lda  P8ZP_SCRATCH_REG_X
-asmsub	SETLFS   (ubyte logical @ A, ubyte device @ X, ubyte address @ Y) -> clobbers() -> () = $FFBA	; set logical file parameters
+		sta  IRQ_SCRATCH_ZPREGX
-asmsub	SETNAM   (ubyte namelen @ A, str filename @ XY) -> clobbers() -> ()	= $FFBD		; set filename parameters
+		lda  P8ZP_SCRATCH_W1
-asmsub	OPEN     () -> clobbers(A,X,Y) -> ()			= $FFC0		; (via 794 ($31A)) open a logical file
+		sta  IRQ_SCRATCH_ZPWORD1
-asmsub	CLOSE    (ubyte logical @ A) -> clobbers(A,X,Y) -> ()	= $FFC3		; (via 796 ($31C)) close a logical file
+		lda  P8ZP_SCRATCH_W1+1
-asmsub	CHKIN    (ubyte logical @ X) -> clobbers(A,X) -> ()	= $FFC6		; (via 798 ($31E)) define an input channel
+		sta  IRQ_SCRATCH_ZPWORD1+1
-asmsub	CHKOUT   (ubyte logical @ X) -> clobbers(A,X) -> ()	= $FFC9		; (via 800 ($320)) define an output channel
+		lda  P8ZP_SCRATCH_W2
-asmsub	CLRCHN   () -> clobbers(A,X) -> ()			= $FFCC		; (via 802 ($322)) restore default devices
+		sta  IRQ_SCRATCH_ZPWORD2
-asmsub	CHRIN    () -> clobbers(Y) -> (ubyte @ A)		= $FFCF		; (via 804 ($324)) input a character (for keyboard, read a whole line from the screen) A=byte read.
+		lda  P8ZP_SCRATCH_W2+1
-asmsub	CHROUT   (ubyte char @ A) -> clobbers() -> ()		= $FFD2		; (via 806 ($326)) output a character
+		sta  IRQ_SCRATCH_ZPWORD2+1
-asmsub	LOAD     (ubyte verify @ A, uword address @ XY) -> clobbers() -> (ubyte @Pc, ubyte @ A, ubyte @ X, ubyte @ Y) = $FFD5	; (via 816 ($330)) load from device
+		; stack protector; make sure we don't clobber the top of the evaluation stack
-asmsub	SAVE     (ubyte zp_startaddr @ A, uword endaddr @ XY) -> clobbers() -> (ubyte @ Pc, ubyte @ A) = $FFD8	; (via 818 ($332)) save to a device
+		dex
-asmsub	SETTIM   (ubyte low @ A, ubyte middle @ X, ubyte high @ Y) -> clobbers() -> ()	= $FFDB		; set the software clock
+		dex
-asmsub	RDTIM    () -> clobbers() -> (ubyte @ A, ubyte @ X, ubyte @ Y) = $FFDE	; read the software clock
+		dex
-asmsub	STOP     () -> clobbers(A,X) -> (ubyte @ Pz, ubyte @ Pc)	= $FFE1		; (via 808 ($328)) check the STOP key
+		dex
-asmsub	GETIN    () -> clobbers(X,Y) -> (ubyte @ A)		= $FFE4		; (via 810 ($32A)) get a character
+		dex
-asmsub	CLALL    () -> clobbers(A,X) -> ()			= $FFE7		; (via 812 ($32C)) close all files
+		dex
-asmsub	UDTIM    () -> clobbers(A,X) -> ()			= $FFEA		; update the software clock
+		cld
-asmsub	SCREEN   () -> clobbers() -> (ubyte @ X, ubyte @ Y)	= $FFED		; read number of screen rows and columns
+		rts
-asmsub	PLOT     (ubyte dir @ Pc, ubyte col @ Y, ubyte row @ X) -> clobbers() -> (ubyte @ X, ubyte @ Y)	= $FFF0		; read/set position of cursor on screen.  See c64scr.PLOT for a 'safe' wrapper that preserves X.
+
-asmsub	IOBASE   () -> clobbers() -> (uword @ XY)		= $FFF3		; read base address of I/O devices
+_irq_handler_end
+		; restore all zp scratch registers and the X register
+		lda  IRQ_SCRATCH_ZPB1
+		sta  P8ZP_SCRATCH_B1
+		lda  IRQ_SCRATCH_ZPREG
+		sta  P8ZP_SCRATCH_REG
+		lda  IRQ_SCRATCH_ZPREGX
+		sta  P8ZP_SCRATCH_REG_X
+		lda  IRQ_SCRATCH_ZPWORD1
+		sta  P8ZP_SCRATCH_W1
+		lda  IRQ_SCRATCH_ZPWORD1+1
+		sta  P8ZP_SCRATCH_W1+1
+		lda  IRQ_SCRATCH_ZPWORD2
+		sta  P8ZP_SCRATCH_W2
+		lda  IRQ_SCRATCH_ZPWORD2+1
+		sta  P8ZP_SCRATCH_W2+1
+		ldx  IRQ_X_REG
+		rts
+
+IRQ_X_REG		.byte  0
+IRQ_SCRATCH_ZPB1	.byte  0
+IRQ_SCRATCH_ZPREG	.byte  0
+IRQ_SCRATCH_ZPREGX	.byte  0
+IRQ_SCRATCH_ZPWORD1	.word  0
+IRQ_SCRATCH_ZPWORD2	.word  0
+
+		}}
+}
+
+asmsub  restore_irqvec() {
+	%asm {{
+		sei
+		lda  #<c64.IRQDFRT
+		sta  c64.CINV
+		lda  #>c64.IRQDFRT
+		sta  c64.CINV+1
+		lda  #0
+		sta  c64.IREQMASK	; disable raster irq
+		lda  #%10000001
+		sta  c64.CIA1ICR	; restore CIA1 irq
+		cli
+		rts
+	}}
+}
+
+asmsub  set_rasterirq(uword rasterpos @ AY) clobbers(A) {
+	%asm {{
+		sei
+		jsr  _setup_raster_irq
+		lda  #<_raster_irq_handler
+		sta  c64.CINV
+		lda  #>_raster_irq_handler
+		sta  c64.CINV+1
+		cli
+		rts
+
+_raster_irq_handler
+		jsr  set_irqvec._irq_handler_init
+		jsr  irq.irq
+		jsr  set_irqvec._irq_handler_end
+		lda  #$ff
+		sta  c64.VICIRQ			; acknowledge raster irq
+		jmp  c64.IRQDFRT
+
+_setup_raster_irq
+		pha
+		lda  #%01111111
+		sta  c64.CIA1ICR    ; "switch off" interrupts signals from cia-1
+		sta  c64.CIA2ICR    ; "switch off" interrupts signals from cia-2
+		and  c64.SCROLY
+		sta  c64.SCROLY     ; clear most significant bit of raster position
+		lda  c64.CIA1ICR    ; ack previous irq
+		lda  c64.CIA2ICR    ; ack previous irq
+		pla
+		sta  c64.RASTER     ; set the raster line number where interrupt should occur
+		cpy  #0
+		beq  +
+		lda  c64.SCROLY
+		ora  #%10000000
+		sta  c64.SCROLY     ; set most significant bit of raster position
++		lda  #%00000001
+		sta  c64.IREQMASK   ;enable raster interrupt signals from vic
+		rts
+	}}
+}
+
+asmsub  set_rasterirq_excl(uword rasterpos @ AY) clobbers(A) {
+	%asm {{
+		sei
+		jsr  set_rasterirq._setup_raster_irq
+		lda  #<_raster_irq_handler
+		sta  c64.CINV
+		lda  #>_raster_irq_handler
+		sta  c64.CINV+1
+		cli
+		rts
+
+_raster_irq_handler
+		jsr  set_irqvec._irq_handler_init
+		jsr  irq.irq
+		jsr  set_irqvec._irq_handler_end
+		lda  #$ff
+		sta  c64.VICIRQ			; acknowledge raster irq
+		jmp  c64.IRQDFEND		; end irq processing - don't call kernel
+
+	}}
+}
+
+; ---- end of C64 specific system utility routines ----
 
-; ---- end of C64 kernal routines ----
 
 }

compiler/res/prog8lib/c64textio.p8

@@ -0,0 +1,545 @@
+; Prog8 definitions for the Text I/O and Screen routines for the Commodore-64
+;
+; Written by Irmen de Jong (irmen@razorvine.net) - license: GNU GPL 3.0
+;
+; indent format: TABS, size=8
+
+
+%import c64lib
+%import conv
+
+
+txt {
+
+asmsub  clear_screen (ubyte char @ A, ubyte color @ Y) clobbers(A)  {
+	; ---- clear the character screen with the given fill character and character color.
+	;      (assumes screen and color matrix are at their default addresses)
+
+	%asm {{
+		pha
+		tya
+		jsr  clear_screencolors
+		pla
+		jsr  clear_screenchars
+		rts
+        }}
+
+}
+
+asmsub  clear_screenchars (ubyte char @ A) clobbers(Y)  {
+	; ---- clear the character screen with the given fill character (leaves colors)
+	;      (assumes screen matrix is at the default address)
+	%asm {{
+		ldy  #0
+_loop		sta  c64.Screen,y
+		sta  c64.Screen+$0100,y
+		sta  c64.Screen+$0200,y
+		sta  c64.Screen+$02e8,y
+		iny
+		bne  _loop
+		rts
+        }}
+}
+
+asmsub  clear_screencolors (ubyte color @ A) clobbers(Y)  {
+	; ---- clear the character screen colors with the given color (leaves characters).
+	;      (assumes color matrix is at the default address)
+	%asm {{
+		ldy  #0
+_loop		sta  c64.Colors,y
+		sta  c64.Colors+$0100,y
+		sta  c64.Colors+$0200,y
+		sta  c64.Colors+$02e8,y
+		iny
+		bne  _loop
+		rts
+        }}
+}
+
+asmsub  scroll_left_full  (ubyte alsocolors @ Pc) clobbers(A, Y)  {
+	; ---- scroll the whole screen 1 character to the left
+	;      contents of the rightmost column are unchanged, you should clear/refill this yourself
+	;      Carry flag determines if screen color data must be scrolled too
+
+	%asm {{
+		stx  P8ZP_SCRATCH_REG_X
+		bcs  +
+		jmp  _scroll_screen
+
++               ; scroll the color memory
+		ldx  #0
+		ldy  #38
+-
+	.for row=0, row<=24, row+=1
+		lda  c64.Colors + 40*row + 1,x
+		sta  c64.Colors + 40*row,x
+	.next
+		inx
+		dey
+		bpl  -
+
+_scroll_screen  ; scroll the screen memory
+		ldx  #0
+		ldy  #38
+-
+	.for row=0, row<=24, row+=1
+		lda  c64.Screen + 40*row + 1,x
+		sta  c64.Screen + 40*row,x
+	.next
+		inx
+		dey
+		bpl  -
+
+		ldx  P8ZP_SCRATCH_REG_X
+		rts
+	}}
+}
+
+asmsub  scroll_right_full  (ubyte alsocolors @ Pc) clobbers(A)  {
+	; ---- scroll the whole screen 1 character to the right
+	;      contents of the leftmost column are unchanged, you should clear/refill this yourself
+	;      Carry flag determines if screen color data must be scrolled too
+	%asm {{
+		stx  P8ZP_SCRATCH_REG_X
+		bcs  +
+		jmp  _scroll_screen
+
++               ; scroll the color memory
+		ldx  #38
+-
+	.for row=0, row<=24, row+=1
+		lda  c64.Colors + 40*row + 0,x
+		sta  c64.Colors + 40*row + 1,x
+	.next
+		dex
+		bpl  -
+
+_scroll_screen  ; scroll the screen memory
+		ldx  #38
+-
+	.for row=0, row<=24, row+=1
+		lda  c64.Screen + 40*row + 0,x
+		sta  c64.Screen + 40*row + 1,x
+	.next
+		dex
+		bpl  -
+
+		ldx  P8ZP_SCRATCH_REG_X
+		rts
+	}}
+}
+
+asmsub  scroll_up_full  (ubyte alsocolors @ Pc) clobbers(A)  {
+	; ---- scroll the whole screen 1 character up
+	;      contents of the bottom row are unchanged, you should refill/clear this yourself
+	;      Carry flag determines if screen color data must be scrolled too
+	%asm {{
+		stx  P8ZP_SCRATCH_REG_X
+		bcs  +
+		jmp  _scroll_screen
+
++               ; scroll the color memory
+		ldx #39
+-
+	.for row=1, row<=24, row+=1
+		lda  c64.Colors + 40*row,x
+		sta  c64.Colors + 40*(row-1),x
+	.next
+		dex
+		bpl  -
+
+_scroll_screen  ; scroll the screen memory
+		ldx #39
+-
+	.for row=1, row<=24, row+=1
+		lda  c64.Screen + 40*row,x
+		sta  c64.Screen + 40*(row-1),x
+	.next
+		dex
+		bpl  -
+
+		ldx  P8ZP_SCRATCH_REG_X
+		rts
+	}}
+}
+
+asmsub  scroll_down_full  (ubyte alsocolors @ Pc) clobbers(A)  {
+	; ---- scroll the whole screen 1 character down
+	;      contents of the top row are unchanged, you should refill/clear this yourself
+	;      Carry flag determines if screen color data must be scrolled too
+	%asm {{
+		stx  P8ZP_SCRATCH_REG_X
+		bcs  +
+		jmp  _scroll_screen
+
++               ; scroll the color memory
+		ldx #39
+-
+	.for row=23, row>=0, row-=1
+		lda  c64.Colors + 40*row,x
+		sta  c64.Colors + 40*(row+1),x
+	.next
+		dex
+		bpl  -
+
+_scroll_screen  ; scroll the screen memory
+		ldx #39
+-
+	.for row=23, row>=0, row-=1
+		lda  c64.Screen + 40*row,x
+		sta  c64.Screen + 40*(row+1),x
+	.next
+		dex
+		bpl  -
+
+		ldx  P8ZP_SCRATCH_REG_X
+		rts
+	}}
+}
+
+asmsub  print (str text @ AY) clobbers(A,Y)  {
+	; ---- print null terminated string from A/Y
+	; note: the compiler contains an optimization that will replace
+	;       a call to this subroutine with a string argument of just one char,
+	;       by just one call to c64.CHROUT of that single char.
+	%asm {{
+		sta  P8ZP_SCRATCH_B1
+		sty  P8ZP_SCRATCH_REG
+		ldy  #0
+-		lda  (P8ZP_SCRATCH_B1),y
+		beq  +
+		jsr  c64.CHROUT
+		iny
+		bne  -
++		rts
+	}}
+}
+
+asmsub  print_ub0  (ubyte value @ A) clobbers(A,Y)  {
+	; ---- print the ubyte in A in decimal form, with left padding 0s (3 positions total)
+	%asm {{
+		stx  P8ZP_SCRATCH_REG_X
+		jsr  conv.ubyte2decimal
+		pha
+		tya
+		jsr  c64.CHROUT
+		pla
+		jsr  c64.CHROUT
+		txa
+		jsr  c64.CHROUT
+		ldx  P8ZP_SCRATCH_REG_X
+		rts
+	}}
+}
+
+asmsub  print_ub  (ubyte value @ A) clobbers(A,Y)  {
+	; ---- print the ubyte in A in decimal form, without left padding 0s
+	%asm {{
+		stx  P8ZP_SCRATCH_REG_X
+		jsr  conv.ubyte2decimal
+_print_byte_digits
+		pha
+		cpy  #'0'
+		beq  +
+		tya
+		jsr  c64.CHROUT
+		pla
+		jsr  c64.CHROUT
+		jmp  _ones
++       pla
+        cmp  #'0'
+        beq  _ones
+        jsr  c64.CHROUT
+_ones   txa
+		jsr  c64.CHROUT
+		ldx  P8ZP_SCRATCH_REG_X
+		rts
+	}}
+}
+
+asmsub  print_b  (byte value @ A) clobbers(A,Y)  {
+	; ---- print the byte in A in decimal form, without left padding 0s
+	%asm {{
+		stx  P8ZP_SCRATCH_REG_X
+		pha
+		cmp  #0
+		bpl  +
+		lda  #'-'
+		jsr  c64.CHROUT
++		pla
+		jsr  conv.byte2decimal
+		jsr  print_ub._print_byte_digits
+		ldx  P8ZP_SCRATCH_REG_X
+		rts
+	}}
+}
+
+asmsub  print_ubhex  (ubyte value @ A, ubyte prefix @ Pc) clobbers(A,Y)  {
+	; ---- print the ubyte in A in hex form (if Carry is set, a radix prefix '$' is printed as well)
+	%asm {{
+		stx  P8ZP_SCRATCH_REG_X
+		bcc  +
+		pha
+		lda  #'$'
+		jsr  c64.CHROUT
+		pla
++		jsr  conv.ubyte2hex
+		jsr  c64.CHROUT
+		tya
+		jsr  c64.CHROUT
+		ldx  P8ZP_SCRATCH_REG_X
+		rts
+	}}
+}
+
+asmsub  print_ubbin  (ubyte value @ A, ubyte prefix @ Pc) clobbers(A,Y)  {
+	; ---- print the ubyte in A in binary form (if Carry is set, a radix prefix '%' is printed as well)
+	%asm {{
+		stx  P8ZP_SCRATCH_REG_X
+		sta  P8ZP_SCRATCH_B1
+		bcc  +
+		lda  #'%'
+		jsr  c64.CHROUT
++		ldy  #8
+-		lda  #'0'
+		asl  P8ZP_SCRATCH_B1
+		bcc  +
+		lda  #'1'
++		jsr  c64.CHROUT
+		dey
+		bne  -
+		ldx  P8ZP_SCRATCH_REG_X
+		rts
+	}}
+}
+
+asmsub  print_uwbin  (uword value @ AY, ubyte prefix @ Pc) clobbers(A,Y)  {
+	; ---- print the uword in A/Y in binary form (if Carry is set, a radix prefix '%' is printed as well)
+	%asm {{
+		pha
+		tya
+		jsr  print_ubbin
+		pla
+		clc
+		jmp  print_ubbin
+	}}
+}
+
+asmsub  print_uwhex  (uword value @ AY, ubyte prefix @ Pc) clobbers(A,Y)  {
+	; ---- print the uword in A/Y in hexadecimal form (4 digits)
+	;      (if Carry is set, a radix prefix '$' is printed as well)
+	%asm {{
+		pha
+		tya
+		jsr  print_ubhex
+		pla
+		clc
+		jmp  print_ubhex
+	}}
+}
+
+asmsub  print_uw0  (uword value @ AY) clobbers(A,Y)  {
+	; ---- print the uword in A/Y in decimal form, with left padding 0s (5 positions total)
+	%asm {{
+	    stx  P8ZP_SCRATCH_REG_X
+		jsr  conv.uword2decimal
+		ldy  #0
+-		lda  conv.uword2decimal.decTenThousands,y
+        beq  +
+		jsr  c64.CHROUT
+		iny
+		bne  -
++		ldx  P8ZP_SCRATCH_REG_X
+		rts
+	}}
+}
+
+asmsub  print_uw  (uword value @ AY) clobbers(A,Y)  {
+	; ---- print the uword in A/Y in decimal form, without left padding 0s
+	%asm {{
+	    stx  P8ZP_SCRATCH_REG_X
+		jsr  conv.uword2decimal
+		ldx  P8ZP_SCRATCH_REG_X
+		ldy  #0
+-		lda  conv.uword2decimal.decTenThousands,y
+		beq  _allzero
+		cmp  #'0'
+		bne  _gotdigit
+		iny
+		bne  -
+
+_gotdigit
+		jsr  c64.CHROUT
+		iny
+		lda  conv.uword2decimal.decTenThousands,y
+		bne  _gotdigit
+		rts
+_allzero
+        lda  #'0'
+        jmp  c64.CHROUT
+	}}
+}
+
+asmsub  print_w  (word value @ AY) clobbers(A,Y)  {
+	; ---- print the (signed) word in A/Y in decimal form, without left padding 0's
+	%asm {{
+		cpy  #0
+		bpl  +
+		pha
+		lda  #'-'
+		jsr  c64.CHROUT
+		tya
+		eor  #255
+		tay
+		pla
+		eor  #255
+		clc
+		adc  #1
+		bcc  +
+		iny
++		jmp  print_uw
+	}}
+}
+
+asmsub  input_chars  (uword buffer @ AY) clobbers(A) -> ubyte @ Y  {
+	; ---- Input a string (max. 80 chars) from the keyboard. Returns length in Y. (string is terminated with a 0 byte as well)
+	;      It assumes the keyboard is selected as I/O channel!
+
+	%asm {{
+		sta  P8ZP_SCRATCH_W1
+		sty  P8ZP_SCRATCH_W1+1
+		ldy  #0				; char counter = 0
+-		jsr  c64.CHRIN
+		cmp  #$0d			; return (ascii 13) pressed?
+		beq  +				; yes, end.
+		sta  (P8ZP_SCRATCH_W1),y	; else store char in buffer
+		iny
+		bne  -
++		lda  #0
+		sta  (P8ZP_SCRATCH_W1),y	; finish string with 0 byte
+		rts
+
+	}}
+}
+
+asmsub  setchr  (ubyte col @Y, ubyte row @A) clobbers(A)  {
+	; ---- set the character in SCRATCH_ZPB1 on the screen matrix at the given position
+	%asm {{
+		sty  P8ZP_SCRATCH_REG
+		asl  a
+		tay
+		lda  _screenrows+1,y
+		sta  _mod+2
+		lda  _screenrows,y
+		clc
+		adc  P8ZP_SCRATCH_REG
+		sta  _mod+1
+		bcc  +
+		inc  _mod+2
++		lda  P8ZP_SCRATCH_B1
+_mod		sta  $ffff		; modified
+		rts
+
+_screenrows	.word  $0400 + range(0, 1000, 40)
+	}}
+}
+
+asmsub  getchr  (ubyte col @Y, ubyte row @A) clobbers(Y) -> ubyte @ A {
+	; ---- get the character in the screen matrix at the given location
+	%asm  {{
+		sty  P8ZP_SCRATCH_B1
+		asl  a
+		tay
+		lda  setchr._screenrows+1,y
+		sta  _mod+2
+		lda  setchr._screenrows,y
+		clc
+		adc  P8ZP_SCRATCH_B1
+		sta  _mod+1
+		bcc  _mod
+		inc  _mod+2
+_mod		lda  $ffff		; modified
+		rts
+	}}
+}
+
+asmsub  setclr  (ubyte col @Y, ubyte row @A) clobbers(A)  {
+	; ---- set the color in SCRATCH_ZPB1 on the screen matrix at the given position
+	%asm {{
+		sty  P8ZP_SCRATCH_REG
+		asl  a
+		tay
+		lda  _colorrows+1,y
+		sta  _mod+2
+		lda  _colorrows,y
+		clc
+		adc  P8ZP_SCRATCH_REG
+		sta  _mod+1
+		bcc  +
+		inc  _mod+2
++		lda  P8ZP_SCRATCH_B1
+_mod		sta  $ffff		; modified
+		rts
+
+_colorrows	.word  $d800 + range(0, 1000, 40)
+	}}
+}
+
+asmsub  getclr  (ubyte col @Y, ubyte row @A) clobbers(Y) -> ubyte @ A {
+	; ---- get the color in the screen color matrix at the given location
+	%asm  {{
+		sty  P8ZP_SCRATCH_B1
+		asl  a
+		tay
+		lda  setclr._colorrows+1,y
+		sta  _mod+2
+		lda  setclr._colorrows,y
+		clc
+		adc  P8ZP_SCRATCH_B1
+		sta  _mod+1
+		bcc  _mod
+		inc  _mod+2
+_mod		lda  $ffff		; modified
+		rts
+	}}
+}
+
+sub  setcc  (ubyte column, ubyte row, ubyte char, ubyte color)  {
+	; ---- set char+color at the given position on the screen
+	%asm {{
+		lda  row
+		asl  a
+		tay
+		lda  setchr._screenrows+1,y
+		sta  _charmod+2
+		adc  #$d4
+		sta  _colormod+2
+		lda  setchr._screenrows,y
+		clc
+		adc  column
+		sta  _charmod+1
+		sta  _colormod+1
+		bcc  +
+		inc  _charmod+2
+		inc  _colormod+2
++		lda  char
+_charmod	sta  $ffff		; modified
+		lda  color
+_colormod	sta  $ffff		; modified
+		rts
+	}}
+}
+
+asmsub  plot  (ubyte col @ Y, ubyte row @ A) clobbers(A) {
+	; ---- safe wrapper around PLOT kernel routine, to save the X register.
+	%asm  {{
+		stx  P8ZP_SCRATCH_REG_X
+		tax
+		clc
+		jsr  c64.PLOT
+		ldx  P8ZP_SCRATCH_REG_X
+		rts
+	}}
+}
+
+}

compiler/res/prog8lib/conv.p8

@@ -0,0 +1,361 @@
+; Prog8 definitions for number conversions routines.
+;
+; Written by Irmen de Jong (irmen@razorvine.net) - license: GNU GPL 3.0
+;
+; indent format: TABS, size=8
+
+
+conv {
+
+; ----- number conversions to decimal strings
+
+asmsub  ubyte2decimal  (ubyte value @ A) -> ubyte @ Y, ubyte @ A, ubyte @ X  {
+	; ---- A to decimal string in Y/A/X  (100s in Y, 10s in A, 1s in X)
+    %asm {{
+        ldy  #uword2decimal.ASCII_0_OFFSET
+        bne  uword2decimal.hex_try200
+        rts
+	}}
+}
+
+asmsub  uword2decimal  (uword value @ AY) -> ubyte @Y, ubyte @A, ubyte @X  {
+    ;  ---- convert 16 bit uword in A/Y to decimal
+    ;  output in uword2decimal.decTenThousands, decThousands, decHundreds, decTens, decOnes
+    ;  (these are terminated by a zero byte so they can be easily printed)
+    ;  also returns Y = 100's, A = 10's, X = 1's
+
+    %asm {{
+
+;Convert 16 bit Hex to Decimal (0-65535) Rev 2
+;By Omegamatrix    Further optimizations by tepples
+; routine from http://forums.nesdev.com/viewtopic.php?f=2&t=11341&start=15
+
+;HexToDec99
+; start in A
+; end with A = 10's, decOnes (also in X)
+
+;HexToDec255
+; start in A
+; end with Y = 100's, A = 10's, decOnes (also in X)
+
+;HexToDec999
+; start with A = high byte, Y = low byte
+; end with Y = 100's, A = 10's, decOnes (also in X)
+; requires 1 extra temp register on top of decOnes, could combine
+; these two if HexToDec65535 was eliminated...
+
+;HexToDec65535
+; start with A/Y (low/high) as 16 bit value
+; end with decTenThousand, decThousand, Y = 100's, A = 10's, decOnes (also in X)
+; (irmen: I store Y and A in decHundreds and decTens too, so all of it can be easily printed)
+
+
+ASCII_0_OFFSET 	= $30
+temp       	    = P8ZP_SCRATCH_B1	; byte in zeropage
+hexHigh      	= P8ZP_SCRATCH_W1	; byte in zeropage
+hexLow       	= P8ZP_SCRATCH_W1+1	; byte in zeropage
+
+
+HexToDec65535; SUBROUTINE
+    sty    hexHigh               ;3  @9
+    sta    hexLow                ;3  @12
+    tya
+    tax                          ;2  @14
+    lsr    a                     ;2  @16
+    lsr    a                     ;2  @18   integer divide 1024 (result 0-63)
+
+    cpx    #$A7                  ;2  @20   account for overflow of multiplying 24 from 43,000 ($A7F8) onward,
+    adc    #1                    ;2  @22   we can just round it to $A700, and the divide by 1024 is fine...
+
+    ;at this point we have a number 1-65 that we have to times by 24,
+    ;add to original sum, and Mod 1024 to get a remainder 0-999
+
+
+    sta    temp                  ;3  @25
+    asl    a                     ;2  @27
+    adc    temp                  ;3  @30  x3
+    tay                          ;2  @32
+    lsr    a                     ;2  @34
+    lsr    a                     ;2  @36
+    lsr    a                     ;2  @38
+    lsr    a                     ;2  @40
+    lsr    a                     ;2  @42
+    tax                          ;2  @44
+    tya                          ;2  @46
+    asl    a                     ;2  @48
+    asl    a                     ;2  @50
+    asl    a                     ;2  @52
+    clc                          ;2  @54
+    adc    hexLow                ;3  @57
+    sta    hexLow                ;3  @60
+    txa                          ;2  @62
+    adc    hexHigh               ;3  @65
+    sta    hexHigh               ;3  @68
+    ror    a                     ;2  @70
+    lsr    a                     ;2  @72
+    tay                          ;2  @74    integer divide 1,000 (result 0-65)
+
+    lsr    a                     ;2  @76    split the 1,000 and 10,000 digit
+    tax                          ;2  @78
+    lda    ShiftedBcdTab,x       ;4  @82
+    tax                          ;2  @84
+    rol    a                     ;2  @86
+    and    #$0F                  ;2  @88
+    ora    #ASCII_0_OFFSET
+    sta    decThousands          ;3  @91
+    txa                          ;2  @93
+    lsr    a                     ;2  @95
+    lsr    a                     ;2  @97
+    lsr    a                     ;2  @99
+    ora    #ASCII_0_OFFSET
+    sta    decTenThousands       ;3  @102
+
+    lda    hexLow                ;3  @105
+    cpy    temp                  ;3  @108
+    bmi    _doSubtract           ;2³ @110/111
+    beq    _useZero               ;2³ @112/113
+    adc    #23 + 24              ;2  @114
+_doSubtract
+    sbc    #23                   ;2  @116
+    sta    hexLow                ;3  @119
+_useZero
+    lda    hexHigh               ;3  @122
+    sbc    #0                    ;2  @124
+
+Start100s
+    and    #$03                  ;2  @126
+    tax                          ;2  @128   0,1,2,3
+    cmp    #2                    ;2  @130
+    rol    a                     ;2  @132   0,2,5,7
+    ora    #ASCII_0_OFFSET
+    tay                          ;2  @134   Y = Hundreds digit
+
+    lda    hexLow                ;3  @137
+    adc    Mod100Tab,x           ;4  @141    adding remainder of 256, 512, and 256+512 (all mod 100)
+    bcs    hex_doSub200             ;2³ @143/144
+
+hex_try200
+    cmp    #200                  ;2  @145
+    bcc    hex_try100               ;2³ @147/148
+hex_doSub200
+    iny                          ;2  @149
+    iny                          ;2  @151
+    sbc    #200                  ;2  @153
+hex_try100
+    cmp    #100                  ;2  @155
+    bcc    HexToDec99            ;2³ @157/158
+    iny                          ;2  @159
+    sbc    #100                  ;2  @161
+
+HexToDec99; SUBROUTINE
+    lsr    a                     ;2  @163
+    tax                          ;2  @165
+    lda    ShiftedBcdTab,x       ;4  @169
+    tax                          ;2  @171
+    rol    a                     ;2  @173
+    and    #$0F                  ;2  @175
+    ora    #ASCII_0_OFFSET
+    sta    decOnes               ;3  @178
+    txa                          ;2  @180
+    lsr    a                     ;2  @182
+    lsr    a                     ;2  @184
+    lsr    a                     ;2  @186
+    ora    #ASCII_0_OFFSET
+
+    ; irmen: load X with ones, and store Y and A too, for easy printing afterwards
+    sty  decHundreds
+    sta  decTens
+    ldx  decOnes
+    rts                          ;6  @192   Y=hundreds, A = tens digit, X=ones digit
+
+
+HexToDec999; SUBROUTINE
+    sty    hexLow                ;3  @9
+    jmp    Start100s             ;3  @12
+
+Mod100Tab
+    .byte 0,56,12,56+12
+
+ShiftedBcdTab
+    .byte $00,$01,$02,$03,$04,$08,$09,$0A,$0B,$0C
+    .byte $10,$11,$12,$13,$14,$18,$19,$1A,$1B,$1C
+    .byte $20,$21,$22,$23,$24,$28,$29,$2A,$2B,$2C
+    .byte $30,$31,$32,$33,$34,$38,$39,$3A,$3B,$3C
+    .byte $40,$41,$42,$43,$44,$48,$49,$4A,$4B,$4C
+
+decTenThousands   	.byte  0
+decThousands    	.byte  0
+decHundreds		.byte  0
+decTens			.byte  0
+decOnes   		.byte  0
+			.byte  0		; zero-terminate the decimal output string
+
+    }}
+}
+
+
+; ----- utility functions ----
+
+
+asmsub  byte2decimal  (byte value @ A) -> ubyte @ Y, ubyte @ A, ubyte @ X  {
+	; ---- A (signed byte) to decimal string in Y/A/X  (100s in Y, 10s in A, 1s in X)
+	;      note: if the number is negative, you have to deal with the '-' yourself!
+	%asm {{
+		cmp  #0
+		bpl  +
+		eor  #255
+		clc
+		adc  #1
++		jmp  ubyte2decimal
+	}}
+}
+
+asmsub  ubyte2hex  (ubyte value @ A) -> ubyte @ A, ubyte @ Y  {
+	; ---- A to hex petscii string in AY (first hex char in A, second hex char in Y)
+	%asm {{
+		stx  P8ZP_SCRATCH_REG_X
+		pha
+		and  #$0f
+		tax
+		ldy  _hex_digits,x
+		pla
+		lsr  a
+		lsr  a
+		lsr  a
+		lsr  a
+		tax
+		lda  _hex_digits,x
+		ldx  P8ZP_SCRATCH_REG_X
+		rts
+
+_hex_digits	.text "0123456789abcdef"	; can probably be reused for other stuff as well
+	}}
+}
+
+asmsub  uword2hex  (uword value @ AY) clobbers(A,Y)  {
+	; ---- convert 16 bit uword in A/Y into 4-character hexadecimal string 'uword2hex.output' (0-terminated)
+	%asm {{
+		sta  P8ZP_SCRATCH_REG
+		tya
+		jsr  ubyte2hex
+		sta  output
+		sty  output+1
+		lda  P8ZP_SCRATCH_REG
+		jsr  ubyte2hex
+		sta  output+2
+		sty  output+3
+		rts
+output	.text  "0000", $00      ; 0-terminated output buffer (to make printing easier)
+	}}
+}
+
+asmsub str2uword(str string @ AY) -> uword @ AY {
+	; -- returns the unsigned word value of the string number argument in AY
+	;    the number may NOT be preceded by a + sign and may NOT contain spaces
+	;    (any non-digit character will terminate the number string that is parsed)
+	%asm {{
+_result = P8ZP_SCRATCH_W2
+		sta  _mod+1
+		sty  _mod+2
+		ldy  #0
+		sty  _result
+		sty  _result+1
+_mod		lda  $ffff,y		; modified
+		sec
+		sbc  #48
+		bpl  +
+_done		; return result
+		lda  _result
+		ldy  _result+1
+		rts
++		cmp  #10
+		bcs  _done
+		; add digit to result
+		pha
+		jsr  _result_times_10
+		pla
+		clc
+		adc  _result
+		sta  _result
+		bcc  +
+		inc  _result+1
++		iny
+		bne  _mod
+		; never reached
+
+_result_times_10     ; (W*4 + W)*2
+		lda  _result+1
+		sta  P8ZP_SCRATCH_REG
+		lda  _result
+		asl  a
+		rol  P8ZP_SCRATCH_REG
+		asl  a
+		rol  P8ZP_SCRATCH_REG
+		clc
+		adc  _result
+		sta  _result
+		lda  P8ZP_SCRATCH_REG
+		adc  _result+1
+		asl  _result
+		rol  a
+		sta  _result+1
+		rts
+	}}
+}
+
+asmsub str2word(str string @ AY) -> word @ AY {
+	; -- returns the signed word value of the string number argument in AY
+	;    the number may be preceded by a + or - sign but may NOT contain spaces
+	;    (any non-digit character will terminate the number string that is parsed)
+	%asm {{
+_result = P8ZP_SCRATCH_W2
+		sta  P8ZP_SCRATCH_W1
+		sty  P8ZP_SCRATCH_W1+1
+		ldy  #0
+		sty  _result
+		sty  _result+1
+		sty  _negative
+		lda  (P8ZP_SCRATCH_W1),y
+		cmp  #'+'
+		bne  +
+		iny
++		cmp  #'-'
+		bne  _parse
+		inc  _negative
+		iny
+_parse		lda  (P8ZP_SCRATCH_W1),y
+		sec
+		sbc  #48
+		bpl  _digit
+_done		; return result
+		lda  _negative
+		beq  +
+		sec
+		lda  #0
+		sbc  _result
+		sta  _result
+		lda  #0
+		sbc  _result+1
+		sta  _result+1
++		lda  _result
+		ldy  _result+1
+		rts
+_digit		cmp  #10
+		bcs  _done
+		; add digit to result
+		pha
+		jsr  str2uword._result_times_10
+		pla
+		clc
+		adc  _result
+		sta  _result
+		bcc  +
+		inc  _result+1
++		iny
+		bne  _parse
+		; never reached
+_negative	.byte  0
+	}}
+}
+
+}

compiler/res/prog8lib/cx16lib.p8

@@ -0,0 +1,201 @@
+; Prog8 definitions for the CommanderX16
+; Including memory registers, I/O registers, Basic and Kernal subroutines.
+;
+; Written by Irmen de Jong (irmen@razorvine.net) - license: GNU GPL 3.0
+;
+; indent format: TABS, size=8
+
+
+c64 {
+
+; ---- kernal routines, these are the same as on the Commodore-64 (hence the same block name) ----
+
+; STROUT --> use screen.print
+; CLEARSCR -> use screen.clear_screen
+; HOMECRSR -> use screen.plot
+
+romsub $FF81 = CINT() clobbers(A,X,Y)                           ; (alias: SCINIT) initialize screen editor and video chip
+romsub $FF84 = IOINIT() clobbers(A, X)                          ; initialize I/O devices (CIA, SID, IRQ)
+romsub $FF87 = RAMTAS() clobbers(A,X,Y)                         ; initialize RAM, tape buffer, screen
+romsub $FF8A = RESTOR() clobbers(A,X,Y)                         ; restore default I/O vectors
+romsub $FF8D = VECTOR(uword userptr @ XY, ubyte dir @ Pc) clobbers(A,Y)     ; read/set I/O vector table
+romsub $FF90 = SETMSG(ubyte value @ A)                          ; set Kernal message control flag
+romsub $FF93 = SECOND(ubyte address @ A) clobbers(A)            ; (alias: LSTNSA) send secondary address after LISTEN
+romsub $FF96 = TKSA(ubyte address @ A) clobbers(A)              ; (alias: TALKSA) send secondary address after TALK
+romsub $FF99 = MEMTOP(uword address @ XY, ubyte dir @ Pc) -> uword @ XY     ; read/set top of memory  pointer
+romsub $FF9C = MEMBOT(uword address @ XY, ubyte dir @ Pc) -> uword @ XY     ; read/set bottom of memory  pointer
+romsub $FF9F = SCNKEY() clobbers(A,X,Y)                         ; scan the keyboard
+romsub $FFA2 = SETTMO(ubyte timeout @ A)                        ; set time-out flag for IEEE bus
+romsub $FFA5 = ACPTR() -> ubyte @ A                             ; (alias: IECIN) input byte from serial bus
+romsub $FFA8 = CIOUT(ubyte databyte @ A)                        ; (alias: IECOUT) output byte to serial bus
+romsub $FFAB = UNTLK() clobbers(A)                              ; command serial bus device to UNTALK
+romsub $FFAE = UNLSN() clobbers(A)                              ; command serial bus device to UNLISTEN
+romsub $FFB1 = LISTEN(ubyte device @ A) clobbers(A)             ; command serial bus device to LISTEN
+romsub $FFB4 = TALK(ubyte device @ A) clobbers(A)               ; command serial bus device to TALK
+romsub $FFB7 = READST() -> ubyte @ A                            ; read I/O status word
+romsub $FFBA = SETLFS(ubyte logical @ A, ubyte device @ X, ubyte address @ Y)   ; set logical file parameters
+romsub $FFBD = SETNAM(ubyte namelen @ A, str filename @ XY)     ; set filename parameters
+romsub $FFC0 = OPEN() clobbers(A,X,Y)                           ; (via 794 ($31A)) open a logical file
+romsub $FFC3 = CLOSE(ubyte logical @ A) clobbers(A,X,Y)         ; (via 796 ($31C)) close a logical file
+romsub $FFC6 = CHKIN(ubyte logical @ X) clobbers(A,X)           ; (via 798 ($31E)) define an input channel
+romsub $FFC9 = CHKOUT(ubyte logical @ X) clobbers(A,X)          ; (via 800 ($320)) define an output channel
+romsub $FFCC = CLRCHN() clobbers(A,X)                           ; (via 802 ($322)) restore default devices
+romsub $FFCF = CHRIN() clobbers(Y) -> ubyte @ A                 ; (via 804 ($324)) input a character (for keyboard, read a whole line from the screen) A=byte read.
+romsub $FFD2 = CHROUT(ubyte char @ A)                           ; (via 806 ($326)) output a character
+romsub $FFD5 = LOAD(ubyte verify @ A, uword address @ XY) -> ubyte @Pc, ubyte @ A, ubyte @ X, ubyte @ Y     ; (via 816 ($330)) load from device
+romsub $FFD8 = SAVE(ubyte zp_startaddr @ A, uword endaddr @ XY) -> ubyte @ Pc, ubyte @ A                    ; (via 818 ($332)) save to a device
+romsub $FFDB = SETTIM(ubyte low @ A, ubyte middle @ X, ubyte high @ Y)      ; set the software clock
+romsub $FFDE = RDTIM() -> ubyte @ A, ubyte @ X, ubyte @ Y       ; read the software clock
+romsub $FFE1 = STOP() clobbers(A,X) -> ubyte @ Pz, ubyte @ Pc   ; (via 808 ($328)) check the STOP key
+romsub $FFE4 = GETIN() clobbers(X,Y) -> ubyte @ A               ; (via 810 ($32A)) get a character
+romsub $FFE7 = CLALL() clobbers(A,X)                            ; (via 812 ($32C)) close all files
+romsub $FFEA = UDTIM() clobbers(A,X)                            ; update the software clock
+romsub $FFED = SCREEN() -> ubyte @ X, ubyte @ Y                 ; read number of screen rows and columns
+romsub $FFF0 = PLOT(ubyte col @ Y, ubyte row @ X, ubyte dir @ Pc) -> ubyte @ X, ubyte @ Y       ; read/set position of cursor on screen.  Use screen.plot for a 'safe' wrapper that preserves X.
+romsub $FFF3 = IOBASE() -> uword @ XY                           ; read base address of I/O devices
+
+}
+
+cx16 {
+
+; ---- Commander X-16 additions on top of C64 kernal routines ----
+; spelling of the names is taken from the Commander X-16 rom sources
+
+; the sixteen virtual 16-bit registers
+&ubyte r0  = $02
+&ubyte r0L = $02
+&ubyte r0H = $03
+&ubyte r1  = $04
+&ubyte r1L = $04
+&ubyte r1H = $05
+&ubyte r2  = $06
+&ubyte r2L = $06
+&ubyte r2H = $07
+&ubyte r3  = $08
+&ubyte r3L = $08
+&ubyte r3H = $09
+&ubyte r4  = $0a
+&ubyte r4L = $0a
+&ubyte r4H = $0b
+&ubyte r5  = $0c
+&ubyte r5L = $0c
+&ubyte r5H = $0d
+&ubyte r6  = $0e
+&ubyte r6L = $0e
+&ubyte r6H = $0f
+&ubyte r7  = $10
+&ubyte r7L = $10
+&ubyte r7H = $11
+&ubyte r8  = $12
+&ubyte r8L = $12
+&ubyte r8H = $13
+&ubyte r9  = $14
+&ubyte r9L = $14
+&ubyte r9H = $15
+&ubyte r10 = $16
+&ubyte r10L    = $16
+&ubyte r10H    = $17
+&ubyte r11     = $18
+&ubyte r11L    = $18
+&ubyte r11H    = $19
+&ubyte r12     = $1a
+&ubyte r12L    = $1a
+&ubyte r12H    = $1b
+&ubyte r13     = $1c
+&ubyte r13L    = $1c
+&ubyte r13H    = $1d
+&ubyte r14     = $1e
+&ubyte r14L    = $1e
+&ubyte r14H    = $1f
+&ubyte r15     = $20
+&ubyte r15L    = $20
+&ubyte r15H    = $21
+
+
+; TODO subroutine args + soubroutine returnvalues + clobber registers
+
+; supported C128 additions
+romsub $ff4a = close_all()
+romsub $ff59 = lkupla()
+romsub $ff5c = lkupsa()
+romsub $ff5f = screen_set_mode()
+romsub $ff62 = screen_set_charset(ubyte charset @A, uword charsetptr @XY) clobbers(A,X,Y)      ; incompatible with C128  dlchr()
+romsub $ff65 = pfkey()
+romsub $ff6e = jsrfar()
+romsub $ff74 = fetch()
+romsub $ff77 = stash()
+romsub $ff7a = cmpare()
+romsub $ff7d = primm()
+
+; X16 additions
+romsub $ff44 = macptr()
+romsub $ff47 = enter_basic()
+romsub $ff68 = mouse_config()
+romsub $ff6b = mouse_get()
+romsub $ff71 = mouse_scan()
+romsub $ff53 = joystick_scan()
+romsub $ff56 = joystick_get()
+romsub $ff4d = clock_set_date_time()
+romsub $ff50 = clock_get_date_time()
+
+; high level graphics & fonts
+romsub $ff20 = GRAPH_init()
+romsub $ff23 = GRAPH_clear()
+romsub $ff26 = GRAPH_set_window()
+romsub $ff29 = GRAPH_set_colors()
+romsub $ff2c = GRAPH_draw_line()
+romsub $ff2f = GRAPH_draw_rect()
+romsub $ff32 = GRAPH_move_rect()
+romsub $ff35 = GRAPH_draw_oval()
+romsub $ff38 = GRAPH_draw_image()
+romsub $ff3b = GRAPH_set_font()
+romsub $ff3e = GRAPH_get_char_size()
+romsub $ff41 = GRAPH_put_char()
+
+; TODO framebuffer API not yet included, include it
+
+romsub $fef0 = sprite_set_image()
+romsub $fef3 = sprite_set_position()
+romsub $fee4 = memory_fill()
+romsub $fee7 = memory_copy()
+romsub $feea = memory_crc()
+romsub $feed = memory_decompress()
+romsub $fedb = console_init()
+romsub $fede = console_put_char()
+romsub $fee1 = console_get_char()
+romsub $fed8 = console_put_image()
+romsub $fed5 = console_set_paging_message()
+romsub $fed2 = kbdbuf_put()
+romsub $fecf = entropy_get()
+romsub $fecc = monitor()
+
+
+
+; ---- end of kernal routines ----
+
+asmsub init_system()  {
+    ; Initializes the machine to a sane starting state.
+    ; Called automatically by the loader program logic.
+    %asm {{
+        sei
+        cld
+        lda  #0
+        sta  $00
+        sta  $01
+        jsr  c64.IOINIT
+        jsr  c64.RESTOR
+        jsr  c64.CINT
+        lda  #0
+        tax
+        tay
+        clc
+        clv
+        cli
+        lda  #66
+        clc
+        jsr  console_put_char
+        rts
+    }}
+}
+
+}

compiler/res/prog8lib/cx16textio.p8

@@ -0,0 +1,240 @@
+; Prog8 definitions for the Text I/O and Screen routines for the CommanderX16
+;
+; Written by Irmen de Jong (irmen@razorvine.net) - license: GNU GPL 3.0
+;
+; indent format: TABS, size=8
+
+
+%import cx16lib
+%import conv
+
+
+txt {
+
+asmsub  clear_screen (ubyte char @ A, ubyte color @ Y) clobbers(A)  {
+	; ---- clear the character screen with the given fill character and character color.
+	;      (assumes screen and color matrix are at their default addresses)
+
+	%asm {{
+	    brk     ; TODO
+        }}
+
+}
+
+asmsub  print (str text @ AY) clobbers(A,Y)  {
+	; ---- print null terminated string from A/Y
+	; note: the compiler contains an optimization that will replace
+	;       a call to this subroutine with a string argument of just one char,
+	;       by just one call to c64.CHROUT of that single char.
+	%asm {{
+		sta  P8ZP_SCRATCH_B1
+		sty  P8ZP_SCRATCH_REG
+		ldy  #0
+-		lda  (P8ZP_SCRATCH_B1),y
+		beq  +
+		jsr  c64.CHROUT
+		iny
+		bne  -
++		rts
+	}}
+}
+
+asmsub  print_ub0  (ubyte value @ A) clobbers(A,Y)  {
+	; ---- print the ubyte in A in decimal form, with left padding 0s (3 positions total)
+	%asm {{
+		stx  P8ZP_SCRATCH_REG_X
+		jsr  conv.ubyte2decimal
+		pha
+		tya
+		jsr  c64.CHROUT
+		pla
+		jsr  c64.CHROUT
+		txa
+		jsr  c64.CHROUT
+		ldx  P8ZP_SCRATCH_REG_X
+		rts
+	}}
+}
+
+asmsub  print_ub  (ubyte value @ A) clobbers(A,Y)  {
+	; ---- print the ubyte in A in decimal form, without left padding 0s
+	%asm {{
+		stx  P8ZP_SCRATCH_REG_X
+		jsr  conv.ubyte2decimal
+_print_byte_digits
+		pha
+		cpy  #'0'
+		beq  +
+		tya
+		jsr  c64.CHROUT
+		pla
+		jsr  c64.CHROUT
+		jmp  _ones
++       pla
+        cmp  #'0'
+        beq  _ones
+        jsr  c64.CHROUT
+_ones   txa
+		jsr  c64.CHROUT
+		ldx  P8ZP_SCRATCH_REG_X
+		rts
+	}}
+}
+
+asmsub  print_b  (byte value @ A) clobbers(A,Y)  {
+	; ---- print the byte in A in decimal form, without left padding 0s
+	%asm {{
+		stx  P8ZP_SCRATCH_REG_X
+		pha
+		cmp  #0
+		bpl  +
+		lda  #'-'
+		jsr  c64.CHROUT
++		pla
+		jsr  conv.byte2decimal
+		jsr  print_ub._print_byte_digits
+		ldx  P8ZP_SCRATCH_REG_X
+		rts
+	}}
+}
+
+asmsub  print_ubhex  (ubyte value @ A, ubyte prefix @ Pc) clobbers(A,Y)  {
+	; ---- print the ubyte in A in hex form (if Carry is set, a radix prefix '$' is printed as well)
+	%asm {{
+		stx  P8ZP_SCRATCH_REG_X
+		bcc  +
+		pha
+		lda  #'$'
+		jsr  c64.CHROUT
+		pla
++		jsr  conv.ubyte2hex
+		jsr  c64.CHROUT
+		tya
+		jsr  c64.CHROUT
+		ldx  P8ZP_SCRATCH_REG_X
+		rts
+	}}
+}
+
+asmsub  print_ubbin  (ubyte value @ A, ubyte prefix @ Pc) clobbers(A,Y)  {
+	; ---- print the ubyte in A in binary form (if Carry is set, a radix prefix '%' is printed as well)
+	%asm {{
+		stx  P8ZP_SCRATCH_REG_X
+		sta  P8ZP_SCRATCH_B1
+		bcc  +
+		lda  #'%'
+		jsr  c64.CHROUT
++		ldy  #8
+-		lda  #'0'
+		asl  P8ZP_SCRATCH_B1
+		bcc  +
+		lda  #'1'
++		jsr  c64.CHROUT
+		dey
+		bne  -
+		ldx  P8ZP_SCRATCH_REG_X
+		rts
+	}}
+}
+
+asmsub  print_uwbin  (uword value @ AY, ubyte prefix @ Pc) clobbers(A,Y)  {
+	; ---- print the uword in A/Y in binary form (if Carry is set, a radix prefix '%' is printed as well)
+	%asm {{
+		pha
+		tya
+		jsr  print_ubbin
+		pla
+		clc
+		jmp  print_ubbin
+	}}
+}
+
+asmsub  print_uwhex  (uword value @ AY, ubyte prefix @ Pc) clobbers(A,Y)  {
+	; ---- print the uword in A/Y in hexadecimal form (4 digits)
+	;      (if Carry is set, a radix prefix '$' is printed as well)
+	%asm {{
+		pha
+		tya
+		jsr  print_ubhex
+		pla
+		clc
+		jmp  print_ubhex
+	}}
+}
+
+asmsub  print_uw0  (uword value @ AY) clobbers(A,Y)  {
+	; ---- print the uword in A/Y in decimal form, with left padding 0s (5 positions total)
+	%asm {{
+	    stx  P8ZP_SCRATCH_REG_X
+		jsr  conv.uword2decimal
+		ldy  #0
+-		lda  conv.uword2decimal.decTenThousands,y
+        beq  +
+		jsr  c64.CHROUT
+		iny
+		bne  -
++		ldx  P8ZP_SCRATCH_REG_X
+		rts
+	}}
+}
+
+asmsub  print_uw  (uword value @ AY) clobbers(A,Y)  {
+	; ---- print the uword in A/Y in decimal form, without left padding 0s
+	%asm {{
+	    stx  P8ZP_SCRATCH_REG_X
+		jsr  conv.uword2decimal
+		ldx  P8ZP_SCRATCH_REG_X
+		ldy  #0
+-		lda  conv.uword2decimal.decTenThousands,y
+		beq  _allzero
+		cmp  #'0'
+		bne  _gotdigit
+		iny
+		bne  -
+
+_gotdigit
+		jsr  c64.CHROUT
+		iny
+		lda  conv.uword2decimal.decTenThousands,y
+		bne  _gotdigit
+		rts
+_allzero
+        lda  #'0'
+        jmp  c64.CHROUT
+	}}
+}
+
+asmsub  print_w  (word value @ AY) clobbers(A,Y)  {
+	; ---- print the (signed) word in A/Y in decimal form, without left padding 0's
+	%asm {{
+		cpy  #0
+		bpl  +
+		pha
+		lda  #'-'
+		jsr  c64.CHROUT
+		tya
+		eor  #255
+		tay
+		pla
+		eor  #255
+		clc
+		adc  #1
+		bcc  +
+		iny
++		jmp  print_uw
+	}}
+}
+
+asmsub  plot  (ubyte col @ Y, ubyte row @ A) clobbers(A) {
+	; ---- safe wrapper around PLOT kernel routine, to save the X register.
+	%asm  {{
+		stx  P8ZP_SCRATCH_REG_X
+		tax
+		clc
+		jsr  c64.PLOT
+		ldx  P8ZP_SCRATCH_REG_X
+		rts
+	}}
+}
+
+}

compiler/res/prog8lib/math.p8

@@ -4,8 +4,6 @@
 ;
 ; indent format: TABS, size=8
 
-%import c64lib
+math {
-
-~ math {
 	%asminclude "library:math.asm", ""
 }

compiler/res/prog8lib/prog8lib.p8

@@ -4,8 +4,6 @@
 ;
 ; indent format: TABS, size=8
 
-%import c64lib
+prog8_lib {
-
-~ prog8_lib {
 	%asminclude "library:prog8lib.asm", ""
 }

compiler/res/version.txt

@@ -1 +1 @@
-1.1 (beta)
+4.0

compiler/src/prog8/CompilerMain.kt

@@ -1,216 +1,143 @@
 package prog8
 
-import prog8.ast.*
+import kotlinx.cli.*
-import prog8.compiler.*
+import prog8.ast.base.AstException
-import prog8.compiler.target.c64.AsmGen
+import prog8.compiler.CompilationResult
-import prog8.compiler.target.c64.C64Zeropage
+import prog8.compiler.compileProgram
-import prog8.optimizing.constantFold
+import prog8.compiler.target.CompilationTarget
-import prog8.optimizing.optimizeStatements
+import prog8.compiler.target.c64.C64MachineDefinition
-import prog8.optimizing.simplifyExpressions
+import prog8.compiler.target.c64.Petscii
+import prog8.compiler.target.c64.codegen.AsmGen
+import prog8.compiler.target.cx16.CX16MachineDefinition
 import prog8.parser.ParsingFailedError
-import prog8.parser.importModule
+import java.io.IOException
-import java.io.File
+import java.nio.file.FileSystems
-import java.io.PrintStream
+import java.nio.file.Path
-import java.lang.Exception
+import java.nio.file.StandardWatchEventKinds
-import java.nio.file.Paths
+import java.time.LocalDateTime
 import kotlin.system.exitProcess
-import kotlin.system.measureTimeMillis
 
 
 fun main(args: Array<String>) {
-
-    // check if the user wants to launch the VM instead
-    if("-vm" in args) {
-        val newArgs = args.toMutableList()
-        newArgs.remove("-vm")
-        return stackVmMain(newArgs.toTypedArray())
-    }
-
     printSoftwareHeader("compiler")
 
-    if (args.isEmpty())
-        usage()
     compileMain(args)
 }
 
-fun printSoftwareHeader(what: String) {
+internal fun printSoftwareHeader(what: String) {
     val buildVersion = object {}.javaClass.getResource("/version.txt").readText().trim()
-    println("\nProg8 $what by Irmen de Jong (irmen@razorvine.net)")
+    println("\nProg8 $what v$buildVersion by Irmen de Jong (irmen@razorvine.net)")
-    println("Version: $buildVersion")
     println("This software is licensed under the GNU GPL 3.0, see https://www.gnu.org/licenses/gpl.html\n")
 }
 
 
-private fun compileMain(args: Array<String>) {
+fun pathFrom(stringPath: String, vararg rest: String): Path  = FileSystems.getDefault().getPath(stringPath, *rest)
-    var emulatorToStart = ""
-    var moduleFile = ""
-    var writeVmCode = false
-    var writeAssembly = true
-    for (arg in args) {
-        if(arg=="-emu")
-            emulatorToStart = "x64"
-        else if(arg=="-emu2")
-            emulatorToStart = "x64sc"
-        else if(arg=="-writevm")
-            writeVmCode = true
-        else if(arg=="-noasm")
-            writeAssembly = false
-        else if(!arg.startsWith("-"))
-            moduleFile = arg
-        else
-            usage()
-    }
-    if(moduleFile.isBlank())
-        usage()
 
-    val filepath = Paths.get(moduleFile).normalize()
+
-    var programname = "?"
+private fun compileMain(args: Array<String>) {
+    val cli = CommandLineInterface("prog8compiler")
+    val startEmulator by cli.flagArgument("-emu", "auto-start the Vice C-64 emulator after successful compilation")
+    val outputDir by cli.flagValueArgument("-out", "directory", "directory for output files instead of current directory", ".")
+    val dontWriteAssembly by cli.flagArgument("-noasm", "don't create assembly code")
+    val dontOptimize by cli.flagArgument("-noopt", "don't perform any optimizations")
+    val watchMode by cli.flagArgument("-watch", "continuous compilation mode (watches for file changes), greatly increases compilation speed")
+    val compilationTarget by cli.flagValueArgument("-target", "compilertarget", "target output of the compiler, currently 'c64' and 'cx16' available", "c64")
+    val moduleFiles by cli.positionalArgumentsList("modules", "main module file(s) to compile", minArgs = 1)
 
     try {
-        val totalTime = measureTimeMillis {
+        cli.parse(args)
-            // import main module and process additional imports
+    } catch (e: Exception) {
-            println("Parsing...")
+        exitProcess(1)
-            val moduleAst = importModule(filepath)
+    }
-            moduleAst.linkParents()
-            var namespace = moduleAst.definingScope()
 
-            // determine special compiler options
+    when(compilationTarget) {
-
+        "c64" -> {
-            val compilerOptions = determineCompilationOptions(moduleAst)
+            with(CompilationTarget) {
-
+                name = "Commodore-64"
-            if (compilerOptions.launcher == LauncherType.BASIC && compilerOptions.output != OutputType.PRG)
+                machine = C64MachineDefinition
-                throw ParsingFailedError("${moduleAst.position} BASIC launcher requires output type PRG.")
+                encodeString = { str, altEncoding ->
-
+                    if(altEncoding) Petscii.encodeScreencode(str, true) else Petscii.encodePetscii(str, true)
-            // perform initial syntax checks and constant folding
+                }
-            println("Syntax check...")
+                decodeString = { bytes, altEncoding ->
-            val heap = HeapValues()
+                    if(altEncoding) Petscii.decodeScreencode(bytes, true) else Petscii.decodePetscii(bytes, true)
-            val time1= measureTimeMillis {
+                }
-                moduleAst.checkIdentifiers(heap)
+                asmGenerator = ::AsmGen
-            }
-            //println(" time1: $time1")
-            val time2 = measureTimeMillis {
-                moduleAst.constantFold(namespace, heap)
-            }
-            //println(" time2: $time2")
-            val time3 = measureTimeMillis {
-                moduleAst.reorderStatements(namespace,heap)     // reorder statements to please the compiler later
-            }
-            //println(" time3: $time3")
-            val time4 = measureTimeMillis {
-                moduleAst.checkValid(namespace, compilerOptions, heap)          // check if tree is valid
-            }
-            //println(" time4: $time4")
-
-            // optimize the parse tree
-            println("Optimizing...")
-            val allScopedSymbolDefinitions = moduleAst.checkIdentifiers(heap)       // useful for checking symbol usage later?
-            while (true) {
-                // keep optimizing expressions and statements until no more steps remain
-                val optsDone1 = moduleAst.simplifyExpressions(namespace, heap)
-                val optsDone2 = moduleAst.optimizeStatements(namespace, heap)
-                if (optsDone1 + optsDone2 == 0)
-                    break
-            }
-
-            namespace = moduleAst.definingScope()       // create it again, it could have changed in the meantime
-            moduleAst.checkValid(namespace, compilerOptions, heap)          // check if final tree is valid
-            moduleAst.checkRecursion(namespace)         // check if there are recursive subroutine calls
-
-            // namespace.debugPrint()
-
-            // compile the syntax tree into stackvmProg form, and optimize that
-            val compiler = Compiler(moduleAst, namespace, heap)
-            val intermediate = compiler.compile(compilerOptions)
-            intermediate.optimize()
-
-            if(writeVmCode) {
-                val stackVmFilename = intermediate.name + ".vm.txt"
-                val stackvmFile = PrintStream(File(stackVmFilename), "utf-8")
-                intermediate.writeCode(stackvmFile)
-                stackvmFile.close()
-                println("StackVM program code written to '$stackVmFilename'")
-            }
-
-            if(writeAssembly) {
-                val zeropage = C64Zeropage(compilerOptions)
-                intermediate.allocateZeropage(zeropage)
-                val assembly = AsmGen(compilerOptions, intermediate, heap, zeropage).compileToAssembly()
-                assembly.assemble(compilerOptions)
-                programname = assembly.name
             }
         }
-        println("\nTotal compilation+assemble time: ${totalTime / 1000.0} sec.")
+        "cx16" -> {
-
+            with(CompilationTarget) {
-    } catch (px: ParsingFailedError) {
+                name = "Commander X16"
-        System.err.print("\u001b[91m")  // bright red
+                machine = CX16MachineDefinition
-        System.err.println(px.message)
+                encodeString = { str, altEncoding ->
-        System.err.print("\u001b[0m")  // reset
+                    if(altEncoding) Petscii.encodeScreencode(str, true) else Petscii.encodePetscii(str, true)
-        exitProcess(1)
-    } catch (x: Exception) {
-        print("\u001b[91m")  // bright red
-        println("\n* internal error *")
-        print("\u001b[0m")  // reset
-        System.out.flush()
-        throw x
-    } catch (x: NotImplementedError) {
-        print("\u001b[91m")  // bright red
-        println("\n* internal error: missing feature/code *")
-        print("\u001b[0m")  // reset
-        System.out.flush()
-        throw x
-    }
-
-    if(emulatorToStart.isNotEmpty()) {
-        println("\nStarting C-64 emulator $emulatorToStart...")
-        val cmdline = listOf(emulatorToStart, "-silent", "-moncommands", "$programname.vice-mon-list",
-                "-autostartprgmode", "1", "-autostart-warp", "-autostart", programname+".prg")
-        val process = ProcessBuilder(cmdline).inheritIO().start()
-        process.waitFor()
-    }
-}
-
-fun determineCompilationOptions(moduleAst: Module): CompilationOptions {
-    val options = moduleAst.statements.filter { it is Directive && it.directive == "%option" }.flatMap { (it as Directive).args }.toSet()
-    val outputType = (moduleAst.statements.singleOrNull { it is Directive && it.directive == "%output" }
-            as? Directive)?.args?.single()?.name?.toUpperCase()
-    val launcherType = (moduleAst.statements.singleOrNull { it is Directive && it.directive == "%launcher" }
-            as? Directive)?.args?.single()?.name?.toUpperCase()
-    moduleAst.loadAddress = (moduleAst.statements.singleOrNull { it is Directive && it.directive == "%address" }
-            as? Directive)?.args?.single()?.int ?: 0
-    val zpoption: String? = (moduleAst.statements.singleOrNull { it is Directive && it.directive == "%zeropage" }
-            as? Directive)?.args?.single()?.name?.toUpperCase()
-    val floatsEnabled = options.any { it.name == "enable_floats" }
-    val zpType: ZeropageType =
-            if (zpoption == null)
-                if(floatsEnabled) ZeropageType.BASICSAFE else ZeropageType.KERNALSAFE
-            else
-                try {
-                    ZeropageType.valueOf(zpoption)
-                } catch (x: IllegalArgumentException) {
-                    ZeropageType.KERNALSAFE
-                    // error will be printed by the astchecker
                 }
-    val zpReserved = moduleAst.statements
+                decodeString = { bytes, altEncoding ->
-            .asSequence()
+                    if(altEncoding) Petscii.decodeScreencode(bytes, true) else Petscii.decodePetscii(bytes, true)
-            .filter { it is Directive && it.directive == "%zpreserved" }
+                }
-            .map { (it as Directive).args }
+                asmGenerator = ::AsmGen
-            .map { it[0].int!!..it[1].int!! }
+            }
-            .toList()
+        }
+        else -> {
+            System.err.println("invalid compilation target. Available are: c64, cx16")
+            exitProcess(1)
+        }
+    }
 
-    return CompilationOptions(
+    val outputPath = pathFrom(outputDir)
-            if (outputType == null) OutputType.PRG else OutputType.valueOf(outputType),
+    if(!outputPath.toFile().isDirectory) {
-            if (launcherType == null) LauncherType.BASIC else LauncherType.valueOf(launcherType),
+        System.err.println("Output path doesn't exist")
-            zpType, zpReserved, floatsEnabled
+        exitProcess(1)
-    )
+    }
-}
 
-private fun usage() {
+    if(watchMode && moduleFiles.size<=1) {
-    System.err.println("Missing argument(s):")
+        val watchservice = FileSystems.getDefault().newWatchService()
-    System.err.println("    [-emu]       auto-start the 'x64' C-64 emulator after successful compilation")
+
-    System.err.println("    [-emu2]      auto-start the 'x64sc' C-64 emulator after successful compilation")
+        while(true) {
-    System.err.println("    [-writevm]   write intermediate vm code to a file as well")
+            val filepath = pathFrom(moduleFiles.single()).normalize()
-    System.err.println("    [-noasm]     don't create assembly code")
+            println("Continuous watch mode active. Main module: $filepath")
-    System.err.println("    [-vm]        launch the prog8 virtual machine instead of the compiler")
+
-    System.err.println("    modulefile   main module file to compile")
+            try {
-    exitProcess(1)
+                val compilationResult = compileProgram(filepath, !dontOptimize, !dontWriteAssembly, outputDir=outputPath)
+                println("Imported files (now watching:)")
+                for (importedFile in compilationResult.importedFiles) {
+                    print("  ")
+                    println(importedFile)
+                    importedFile.parent.register(watchservice, StandardWatchEventKinds.ENTRY_MODIFY)
+                }
+                println("[${LocalDateTime.now().withNano(0)}]  Waiting for file changes.")
+                val event = watchservice.take()
+                for(changed in event.pollEvents()) {
+                    val changedPath = changed.context() as Path
+                    println("  change detected: $changedPath")
+                }
+                event.reset()
+                println("\u001b[H\u001b[2J")      // clear the screen
+            } catch (x: Exception) {
+                throw x
+            }
+        }
+
+    } else {
+        for(filepathRaw in moduleFiles) {
+            val filepath = pathFrom(filepathRaw).normalize()
+            val compilationResult: CompilationResult
+            try {
+                compilationResult = compileProgram(filepath, !dontOptimize, !dontWriteAssembly, outputDir=outputPath)
+                if(!compilationResult.success)
+                    exitProcess(1)
+            } catch (x: ParsingFailedError) {
+                exitProcess(1)
+            } catch (x: AstException) {
+                exitProcess(1)
+            }
+
+            if (startEmulator) {
+                if (compilationResult.programName.isEmpty())
+                    println("\nCan't start emulator because no program was assembled.")
+                else if(startEmulator) {
+                    CompilationTarget.machine.launchEmulator(compilationResult.programName)
+                }
+            }
+        }
+    }
 }

compiler/src/prog8/StackVmMain.kt

@@ -1,46 +0,0 @@
-package prog8
-
-import prog8.stackvm.*
-import java.awt.EventQueue
-import javax.swing.Timer
-import kotlin.system.exitProcess
-
-fun main(args: Array<String>) {
-    stackVmMain(args)
-}
-
-fun stackVmMain(args: Array<String>) {
-    printSoftwareHeader("StackVM")
-
-    if(args.size != 1) {
-        System.err.println("requires one argument: name of stackvm sourcecode file")
-        exitProcess(1)
-    }
-
-    val program = Program.load(args.first())
-    val vm = StackVm(traceOutputFile = null)
-    val dialog = ScreenDialog()
-    vm.load(program, dialog.canvas)
-    EventQueue.invokeLater {
-        dialog.pack()
-        dialog.isVisible = true
-        dialog.start()
-
-        val programTimer = Timer(10) { a ->
-            try {
-                vm.step()
-            } catch(bp: VmBreakpointException) {
-                println("Breakpoint: execution halted. Press enter to resume.")
-                readLine()
-            } catch (tx: VmTerminationException) {
-                println("Execution halted: ${tx.message}")
-                (a.source as Timer).stop()
-            }
-        }
-
-        val irqTimer = Timer(1000/60) { a -> vm.irq(a.`when`) }
-
-        programTimer.start()
-        irqTimer.start()
-    }
-}

compiler/src/prog8/ast/AstIdentifiersChecker.kt

@@ -1,238 +0,0 @@
-package prog8.ast
-
-import prog8.compiler.HeapValues
-import prog8.functions.BuiltinFunctions
-
-/**
- * Checks the validity of all identifiers (no conflicts)
- * Also builds a list of all (scoped) symbol definitions
- * Also makes sure that subroutine's parameters also become local variable decls in the subroutine's scope.
- * Finally, it also makes sure the datatype of all Var decls and sub Return values is set correctly.
- */
-
-fun Module.checkIdentifiers(heap: HeapValues): MutableMap<String, IStatement> {
-    val checker = AstIdentifiersChecker(heap)
-    this.process(checker)
-
-    // add any anonymous variables for heap values that are used, and replace literalvalue by identifierref
-    for (variable in checker.anonymousVariablesFromHeap) {
-        val scope = variable.first.definingScope()
-        scope.statements.add(variable.second)
-        val parent = variable.first.parent
-        when {
-            parent is Assignment && parent.value === variable.first -> {
-                val idref = IdentifierReference(listOf("auto_heap_value_${variable.first.heapId}"), variable.first.position)
-                idref.linkParents(parent)
-                parent.value = idref
-            }
-            parent is IFunctionCall -> {
-                val parameterPos = parent.arglist.indexOf(variable.first)
-                val idref = IdentifierReference(listOf("auto_heap_value_${variable.first.heapId}"), variable.first.position)
-                idref.linkParents(parent)
-                parent.arglist[parameterPos] = idref
-            }
-            else -> TODO("replace literalvalue by identifierref: $variable  (in $parent)")
-        }
-    }
-
-    printErrors(checker.result(), name)
-    return checker.symbols
-}
-
-
-private class AstIdentifiersChecker(val heap: HeapValues) : IAstProcessor {
-    private val checkResult: MutableList<AstException> = mutableListOf()
-
-    var symbols: MutableMap<String, IStatement> = mutableMapOf()
-        private set
-
-    fun result(): List<AstException> {
-        return checkResult
-    }
-
-    private fun nameError(name: String, position: Position, existing: IStatement) {
-        checkResult.add(NameError("name conflict '$name', first defined in ${existing.position.file} line ${existing.position.line}", position))
-    }
-
-    override fun process(block: Block): IStatement {
-        val scopedName = block.scopedname
-        val existing = symbols[scopedName]
-        if(existing!=null) {
-            nameError(block.name, block.position, existing)
-        } else {
-            symbols[scopedName] = block
-        }
-        return super.process(block)
-    }
-
-    override fun process(functionCall: FunctionCall): IExpression {
-        if(functionCall.target.nameInSource.size==1 && functionCall.target.nameInSource[0]=="lsb") {
-            // lsb(...) is just an alias for type cast to ubyte, so replace with "... as ubyte"
-            val typecast = TypecastExpression(functionCall.arglist.single(), DataType.UBYTE, functionCall.position)
-            typecast.linkParents(functionCall.parent)
-            return super.process(typecast)
-        }
-        return super.process(functionCall)
-    }
-
-    override fun process(decl: VarDecl): IStatement {
-        // first, check if there are datatype errors on the vardecl
-        decl.datatypeErrors.forEach { checkResult.add(it) }
-
-        // now check the identifier
-        if(decl.name in BuiltinFunctions)
-            // the builtin functions can't be redefined
-            checkResult.add(NameError("builtin function cannot be redefined", decl.position))
-
-        val scopedName = decl.scopedname
-        val existing = symbols[scopedName]
-        if(existing!=null) {
-            nameError(decl.name, decl.position, existing)
-        } else {
-            symbols[scopedName] = decl
-        }
-        return super.process(decl)
-    }
-
-    override fun process(subroutine: Subroutine): IStatement {
-        if(subroutine.name in BuiltinFunctions) {
-            // the builtin functions can't be redefined
-            checkResult.add(NameError("builtin function cannot be redefined", subroutine.position))
-        } else {
-            if (subroutine.parameters.any { it.name in BuiltinFunctions })
-                checkResult.add(NameError("builtin function name cannot be used as parameter", subroutine.position))
-
-            val scopedName = subroutine.scopedname
-            val existing = symbols[scopedName]
-            if (existing != null) {
-                nameError(subroutine.name, subroutine.position, existing)
-            } else {
-                symbols[scopedName] = subroutine
-            }
-
-            // check that there are no local variables that redefine the subroutine's parameters
-            val allDefinedNames = subroutine.allLabelsAndVariables()
-            val paramNames = subroutine.parameters.map { it.name }.toSet()
-            val paramsToCheck = paramNames.intersect(allDefinedNames)
-            for(name in paramsToCheck) {
-                val thing = subroutine.getLabelOrVariable(name)!!
-                if(thing.position != subroutine.position)
-                    nameError(name, thing.position, subroutine)
-            }
-
-            // inject subroutine params as local variables (if they're not there yet) (for non-kernel subroutines and non-asm parameters)
-            // NOTE:
-            // - numeric types BYTE and WORD and FLOAT are passed by value;
-            // - strings, arrays, matrices are passed by reference (their 16-bit address is passed as an uword parameter)
-            if(subroutine.asmAddress==null) {
-                if(subroutine.asmParameterRegisters.isEmpty()) {
-                    subroutine.parameters
-                            .filter { it.name !in allDefinedNames }
-                            .forEach {
-                                val vardecl = VarDecl(VarDeclType.VAR, it.type, false, null, it.name, null, subroutine.position)
-                                vardecl.linkParents(subroutine)
-                                subroutine.statements.add(0, vardecl)
-                            }
-                }
-            }
-        }
-        return super.process(subroutine)
-    }
-
-    override fun process(label: Label): IStatement {
-        if(label.name in BuiltinFunctions) {
-            // the builtin functions can't be redefined
-            checkResult.add(NameError("builtin function cannot be redefined", label.position))
-        } else {
-            val scopedName = label.scopedname
-            val existing = symbols[scopedName]
-            if (existing != null) {
-                nameError(label.name, label.position, existing)
-            } else {
-                symbols[scopedName] = label
-            }
-        }
-        return super.process(label)
-    }
-
-    override fun process(forLoop: ForLoop): IStatement {
-        // If the for loop has a decltype, it means to declare the loopvar inside the loop body
-        // rather than reusing an already declared loopvar from an outer scope.
-        // For loops that loop over an interable variable (instead of a range of numbers) get an
-        // additional interation count variable in their scope.
-        if(forLoop.loopRegister!=null) {
-            if(forLoop.decltype!=null)
-                checkResult.add(SyntaxError("register loop variables cannot be explicitly declared with a datatype", forLoop.position))
-            if(forLoop.loopRegister == Register.X)
-                printWarning("writing to the X register is dangerous, because it's used as an internal pointer", forLoop.position)
-        } else if(forLoop.loopVar!=null) {
-            val varName = forLoop.loopVar.nameInSource.last()
-            if(forLoop.decltype!=null) {
-                val existing = if(forLoop.body.isEmpty()) null else forLoop.body.lookup(forLoop.loopVar.nameInSource, forLoop.body.statements.first())
-                if(existing==null) {
-                    // create the local scoped for loop variable itself
-                    val vardecl = VarDecl(VarDeclType.VAR, forLoop.decltype, true, null, varName, null, forLoop.loopVar.position)
-                    vardecl.linkParents(forLoop.body)
-                    forLoop.body.statements.add(0, vardecl)
-                    forLoop.loopVar.parent = forLoop.body   // loopvar 'is defined in the body'
-                }
-
-            }
-
-            if(forLoop.iterable !is RangeExpr) {
-                val existing = if(forLoop.body.isEmpty()) null else forLoop.body.lookup(listOf(ForLoop.iteratorLoopcounterVarname), forLoop.body.statements.first())
-                if(existing==null) {
-                    // create loop iteration counter variable (without value, to avoid an assignment)
-                    val vardecl = VarDecl(VarDeclType.VAR, DataType.UBYTE, true, null, ForLoop.iteratorLoopcounterVarname, null, forLoop.loopVar.position)
-                    vardecl.linkParents(forLoop.body)
-                    forLoop.body.statements.add(0, vardecl)
-                    forLoop.loopVar.parent = forLoop.body   // loopvar 'is defined in the body'
-                }
-            }
-        }
-        return super.process(forLoop)
-    }
-
-    override fun process(assignTarget: AssignTarget): AssignTarget {
-        if(assignTarget.register==Register.X)
-            printWarning("writing to the X register is dangerous, because it's used as an internal pointer", assignTarget.position)
-        return super.process(assignTarget)
-    }
-
-    override fun process(returnStmt: Return): IStatement {
-        if(returnStmt.values.isNotEmpty()) {
-            // possibly adjust any literal values returned, into the desired returning data type
-            val subroutine = returnStmt.definingSubroutine()!!
-            if(subroutine.returntypes.size!=returnStmt.values.size)
-                return returnStmt  // mismatch in number of return values, error will be printed later.
-            val newValues = mutableListOf<IExpression>()
-            for(returnvalue in returnStmt.values.zip(subroutine.returntypes)) {
-                val lval = returnvalue.first as? LiteralValue
-                if(lval!=null) {
-                    val adjusted = lval.intoDatatype(returnvalue.second)
-                    if(adjusted!=null && adjusted !== lval)
-                        newValues.add(adjusted)
-                    else
-                        newValues.add(lval)
-                }
-                else
-                    newValues.add(returnvalue.first)
-            }
-            returnStmt.values = newValues
-        }
-        return super.process(returnStmt)
-    }
-
-
-    internal val anonymousVariablesFromHeap = mutableSetOf<Pair<LiteralValue, VarDecl>>()
-
-    override fun process(literalValue: LiteralValue): LiteralValue {
-        if(literalValue.heapId!=null && literalValue.parent !is VarDecl) {
-            // a literal value that's not declared as a variable, which refers to something on the heap.
-            // we need to introduce an auto-generated variable for this to be able to refer to the value!
-            val variable = VarDecl(VarDeclType.VAR, literalValue.type, false, null, "auto_heap_value_${literalValue.heapId}", literalValue, literalValue.position)
-            anonymousVariablesFromHeap.add(Pair(literalValue, variable))
-        }
-        return super.process(literalValue)
-    }
-}

compiler/src/prog8/ast/AstRecursionChecker.kt

@@ -1,120 +0,0 @@
-package prog8.ast
-
-/**
- * Checks for the occurrence of recursive subroutine calls
- */
-
-fun Module.checkRecursion(namespace: INameScope) {
-    val checker = AstRecursionChecker(namespace)
-    this.process(checker)
-    printErrors(checker.result(), name)
-}
-
-
-private class DirectedGraph<VT> {
-    private val graph = mutableMapOf<VT, MutableSet<VT>>()
-    private var uniqueVertices = mutableSetOf<VT>()
-    val numVertices : Int
-        get() = uniqueVertices.size
-
-    fun add(from: VT, to: VT) {
-        var targets = graph[from]
-        if(targets==null) {
-            targets = mutableSetOf()
-            graph[from] = targets
-        }
-        targets.add(to)
-        uniqueVertices.add(from)
-        uniqueVertices.add(to)
-    }
-
-    fun print() {
-        println("#vertices: $numVertices")
-        graph.forEach { from, to ->
-            println("$from   CALLS:")
-            to.forEach { println("   $it") }
-        }
-        val cycle = checkForCycle()
-        if(cycle.isNotEmpty()) {
-            println("CYCLIC!  $cycle")
-        }
-    }
-
-    fun checkForCycle(): MutableList<VT> {
-        val visited = uniqueVertices.associate { it to false }.toMutableMap()
-        val recStack = uniqueVertices.associate { it to false }.toMutableMap()
-        val cycle = mutableListOf<VT>()
-        for(node in uniqueVertices) {
-            if(isCyclicUntil(node, visited, recStack, cycle))
-                return cycle
-        }
-        return mutableListOf()
-    }
-
-    private fun isCyclicUntil(node: VT,
-                              visited: MutableMap<VT, Boolean>,
-                              recStack: MutableMap<VT, Boolean>,
-                              cycleNodes: MutableList<VT>): Boolean {
-
-        if(recStack[node]==true) return true
-        if(visited[node]==true) return false
-
-        // mark current node as visited and add to recursion stack
-        visited[node] = true
-        recStack[node] = true
-
-        // recurse for all neighbours
-        val neighbors = graph[node]
-        if(neighbors!=null) {
-            for (neighbour in neighbors) {
-                if (isCyclicUntil(neighbour, visited, recStack, cycleNodes)) {
-                    cycleNodes.add(node)
-                    return true
-                }
-            }
-        }
-
-        // pop node from recursion stack
-        recStack[node] = false
-        return false
-    }
-}
-
-
-private class AstRecursionChecker(private val namespace: INameScope) : IAstProcessor {
-    private val callGraph = DirectedGraph<INameScope>()
-
-    fun result(): List<AstException> {
-        val cycle = callGraph.checkForCycle()
-        if(cycle.isEmpty())
-            return emptyList()
-        val chain = cycle.joinToString(" <-- ") { "${it.name} at ${it.position}" }
-        return listOf(AstException("Program contains recursive subroutine calls, this is not supported. Recursive chain:\n (a subroutine call in) $chain"))
-    }
-
-    override fun process(functionCall: FunctionCallStatement): IStatement {
-        val scope = functionCall.definingScope()
-        val targetStatement = functionCall.target.targetStatement(namespace)
-        if(targetStatement!=null) {
-            val targetScope = when (targetStatement) {
-                is Subroutine -> targetStatement
-                else -> targetStatement.definingScope()
-            }
-            callGraph.add(scope, targetScope)
-        }
-        return super.process(functionCall)
-    }
-
-    override fun process(functionCall: FunctionCall): IExpression {
-        val scope = functionCall.definingScope()
-        val targetStatement = functionCall.target.targetStatement(namespace)
-        if(targetStatement!=null) {
-            val targetScope = when (targetStatement) {
-                is Subroutine -> targetStatement
-                else -> targetStatement.definingScope()
-            }
-            callGraph.add(scope, targetScope)
-        }
-        return super.process(functionCall)
-    }
-}

compiler/src/prog8/ast/AstToSourceCode.kt

@@ -0,0 +1,432 @@
+package prog8.ast
+
+import prog8.ast.antlr.escape
+import prog8.ast.base.DataType
+import prog8.ast.base.NumericDatatypes
+import prog8.ast.base.VarDeclType
+import prog8.ast.expressions.*
+import prog8.ast.processing.IAstVisitor
+import prog8.ast.statements.*
+import prog8.compiler.toHex
+
+class AstToSourceCode(val output: (text: String) -> Unit, val program: Program): IAstVisitor {
+    private var scopelevel = 0
+
+    private fun indent(s: String) = "    ".repeat(scopelevel) + s
+    private fun outputln(text: String) = output(text + "\n")
+    private fun outputlni(s: Any) = outputln(indent(s.toString()))
+    private fun outputi(s: Any) = output(indent(s.toString()))
+
+    override fun visit(program: Program) {
+        outputln("============= PROGRAM ${program.name} (FROM AST) ===============")
+        super.visit(program)
+        outputln("============= END PROGRAM ${program.name} (FROM AST) ===========")
+    }
+
+    override fun visit(module: Module) {
+        if(!module.isLibraryModule) {
+            outputln("; ----------- module: ${module.name} -----------")
+            super.visit(module)
+        }
+        else outputln("; library module skipped: ${module.name}")
+    }
+
+    override fun visit(block: Block) {
+        val addr = if(block.address!=null) block.address.toHex() else ""
+        outputln("~ ${block.name} $addr {")
+        scopelevel++
+        for(stmt in block.statements) {
+            outputi("")
+            stmt.accept(this)
+            output("\n")
+        }
+        scopelevel--
+        outputln("}\n")
+    }
+
+    override fun visit(expr: PrefixExpression) {
+        if(expr.operator.any { it.isLetter() })
+            output(" ${expr.operator} ")
+        else
+            output(expr.operator)
+        expr.expression.accept(this)
+    }
+
+    override fun visit(expr: BinaryExpression) {
+        expr.left.accept(this)
+        if(expr.operator.any { it.isLetter() })
+            output(" ${expr.operator} ")
+        else
+            output(expr.operator)
+        expr.right.accept(this)
+    }
+
+    override fun visit(directive: Directive) {
+        output("${directive.directive} ")
+        for(arg in directive.args) {
+            when {
+                arg.int!=null -> output(arg.int.toString())
+                arg.name!=null -> output(arg.name)
+                arg.str!=null -> output("\"${arg.str}\"")
+            }
+            if(arg!==directive.args.last())
+                output(",")
+        }
+        output("\n")
+    }
+
+    private fun datatypeString(dt: DataType): String {
+        return when(dt) {
+            in NumericDatatypes -> dt.toString().toLowerCase()
+            DataType.STR -> dt.toString().toLowerCase()
+            DataType.ARRAY_UB -> "ubyte["
+            DataType.ARRAY_B -> "byte["
+            DataType.ARRAY_UW -> "uword["
+            DataType.ARRAY_W -> "word["
+            DataType.ARRAY_F -> "float["
+            DataType.STRUCT -> ""       // the name of the struct is enough
+            else -> "?????2"
+        }
+    }
+
+    override fun visit(structDecl: StructDecl) {
+        outputln("struct ${structDecl.name} {")
+        scopelevel++
+        for(decl in structDecl.statements) {
+            outputi("")
+            decl.accept(this)
+            output("\n")
+        }
+        scopelevel--
+        outputlni("}")
+    }
+
+    override fun visit(decl: VarDecl) {
+
+        // if the vardecl is a parameter of a subroutine, don't output it again
+        val paramNames = (decl.definingScope() as? Subroutine)?.parameters?.map { it.name }
+        if(paramNames!=null && decl.name in paramNames)
+            return
+
+        when(decl.type) {
+            VarDeclType.VAR -> {}
+            VarDeclType.CONST -> output("const ")
+            VarDeclType.MEMORY -> output("&")
+        }
+        output(decl.struct?.name ?: "")
+        output(datatypeString(decl.datatype))
+        if(decl.arraysize!=null) {
+            decl.arraysize!!.index.accept(this)
+        }
+        if(decl.isArray)
+            output("]")
+
+        if(decl.zeropage == ZeropageWish.REQUIRE_ZEROPAGE || decl.zeropage==ZeropageWish.PREFER_ZEROPAGE)
+            output(" @zp")
+        output(" ${decl.name} ")
+        if(decl.value!=null) {
+            output("= ")
+            decl.value?.accept(this)
+        }
+    }
+
+    override fun visit(subroutine: Subroutine) {
+        output("\n")
+        if(subroutine.isAsmSubroutine) {
+            outputi("asmsub ${subroutine.name} (")
+            for(param in subroutine.parameters.zip(subroutine.asmParameterRegisters)) {
+                val reg =
+                        when {
+                            param.second.stack -> "stack"
+                            param.second.registerOrPair!=null -> param.second.registerOrPair.toString()
+                            param.second.statusflag!=null -> param.second.statusflag.toString()
+                            else -> "?????1"
+                        }
+                output("${datatypeString(param.first.type)} ${param.first.name} @$reg")
+                if(param.first!==subroutine.parameters.last())
+                    output(", ")
+            }
+        }
+        else {
+            outputi("sub ${subroutine.name} (")
+            for(param in subroutine.parameters) {
+                output("${datatypeString(param.type)} ${param.name}")
+                if(param!==subroutine.parameters.last())
+                    output(", ")
+            }
+        }
+        output(") ")
+        if(subroutine.asmClobbers.isNotEmpty()) {
+            output("-> clobbers (")
+            val regs = subroutine.asmClobbers.toList().sorted()
+            for(r in regs) {
+                output(r.toString())
+                if(r!==regs.last())
+                    output(",")
+            }
+            output(") ")
+        }
+        if(subroutine.returntypes.any()) {
+            val rt = subroutine.returntypes.single()
+            output("-> ${datatypeString(rt)} ")
+        }
+        if(subroutine.asmAddress!=null)
+            outputln("= ${subroutine.asmAddress.toHex()}")
+        else {
+            outputln("{ ")
+            scopelevel++
+            outputStatements(subroutine.statements)
+            scopelevel--
+            outputi("}")
+        }
+    }
+
+    private fun outputStatements(statements: List<Statement>) {
+        for(stmt in statements) {
+            outputi("")
+            stmt.accept(this)
+            output("\n")
+        }
+    }
+
+    override fun visit(functionCall: FunctionCall) {
+        printout(functionCall as IFunctionCall)
+    }
+
+    override fun visit(functionCallStatement: FunctionCallStatement) {
+        printout(functionCallStatement as IFunctionCall)
+    }
+
+    private fun printout(call: IFunctionCall) {
+        call.target.accept(this)
+        output("(")
+        for(arg in call.args) {
+            arg.accept(this)
+            if(arg!==call.args.last())
+                output(", ")
+        }
+        output(")")
+    }
+
+    override fun visit(identifier: IdentifierReference) {
+        output(identifier.nameInSource.joinToString("."))
+    }
+
+    override fun visit(jump: Jump) {
+        output("goto ")
+        when {
+            jump.address!=null -> output(jump.address.toHex())
+            jump.generatedLabel!=null -> output(jump.generatedLabel)
+            jump.identifier!=null -> jump.identifier.accept(this)
+        }
+    }
+
+    override fun visit(ifStatement: IfStatement) {
+        output("if ")
+        ifStatement.condition.accept(this)
+        output(" ")
+        ifStatement.truepart.accept(this)
+        if(ifStatement.elsepart.statements.isNotEmpty()) {
+            output(" else ")
+            ifStatement.elsepart.accept(this)
+        }
+    }
+
+    override fun visit(branchStatement: BranchStatement) {
+        output("if_${branchStatement.condition.toString().toLowerCase()} ")
+        branchStatement.truepart.accept(this)
+        if(branchStatement.elsepart.statements.isNotEmpty()) {
+            output(" else ")
+            branchStatement.elsepart.accept(this)
+        }
+    }
+
+    override fun visit(range: RangeExpr) {
+        range.from.accept(this)
+        output(" to ")
+        range.to.accept(this)
+        output(" step ")
+        range.step.accept(this)
+        output(" ")
+    }
+
+    override fun visit(label: Label) {
+        output("\n")
+        output("${label.name}:")
+    }
+
+    override fun visit(numLiteral: NumericLiteralValue) {
+        output(numLiteral.number.toString())
+    }
+
+    override fun visit(string: StringLiteralValue) {
+        output("\"${escape(string.value)}\"")
+    }
+
+    override fun visit(array: ArrayLiteralValue) {
+        outputListMembers(array.value.asSequence(), '[', ']')
+    }
+
+    private fun outputListMembers(array: Sequence<Expression>, openchar: Char, closechar: Char) {
+        var counter = 0
+        output(openchar.toString())
+        scopelevel++
+        for (v in array) {
+            v.accept(this)
+            if (v !== array.last())
+                output(", ")
+            counter++
+            if (counter > 16) {
+                outputln("")
+                outputi("")
+                counter = 0
+            }
+        }
+        scopelevel--
+        output(closechar.toString())
+    }
+
+    override fun visit(assignment: Assignment) {
+        val binExpr = assignment.value as? BinaryExpression
+        if(binExpr!=null && binExpr.left isSameAs assignment.target
+                && binExpr.operator !in setOf("and", "or", "xor")
+                && binExpr.operator !in comparisonOperators) {
+            // we only support the inplace assignments of the form A = A <operator> <value>
+            assignment.target.accept(this)
+            output(" ${binExpr.operator}= ")
+            binExpr.right.accept(this)
+        } else {
+            assignment.target.accept(this)
+            output(" = ")
+            assignment.value.accept(this)
+        }
+    }
+
+    override fun visit(postIncrDecr: PostIncrDecr) {
+        postIncrDecr.target.accept(this)
+        output(postIncrDecr.operator)
+    }
+
+    override fun visit(breakStmt: Break) {
+        output("break")
+    }
+
+    override fun visit(forLoop: ForLoop) {
+        output("for ")
+        forLoop.loopVar.accept(this)
+        output(" in ")
+        forLoop.iterable.accept(this)
+        output(" ")
+        forLoop.body.accept(this)
+    }
+
+    override fun visit(whileLoop: WhileLoop) {
+        output("while ")
+        whileLoop.condition.accept(this)
+        output(" ")
+        whileLoop.body.accept(this)
+    }
+
+    override fun visit(repeatLoop: RepeatLoop) {
+        output("repeat ")
+        repeatLoop.iterations?.accept(this)
+        output(" ")
+        repeatLoop.body.accept(this)
+    }
+
+    override fun visit(untilLoop: UntilLoop) {
+        output("do ")
+        untilLoop.body.accept(this)
+        output(" until ")
+        untilLoop.untilCondition.accept(this)
+    }
+
+    override fun visit(returnStmt: Return) {
+        output("return ")
+        returnStmt.value?.accept(this)
+    }
+
+    override fun visit(arrayIndexedExpression: ArrayIndexedExpression) {
+        arrayIndexedExpression.identifier.accept(this)
+        output("[")
+        arrayIndexedExpression.arrayspec.index.accept(this)
+        output("]")
+    }
+
+    override fun visit(assignTarget: AssignTarget) {
+        assignTarget.memoryAddress?.accept(this)
+        assignTarget.identifier?.accept(this)
+        assignTarget.arrayindexed?.accept(this)
+    }
+
+    override fun visit(scope: AnonymousScope) {
+        outputln("{")
+        scopelevel++
+        outputStatements(scope.statements)
+        scopelevel--
+        outputi("}")
+    }
+
+    override fun visit(typecast: TypecastExpression) {
+        output("(")
+        typecast.expression.accept(this)
+        output(" as ${datatypeString(typecast.type)}) ")
+    }
+
+    override fun visit(memread: DirectMemoryRead) {
+        output("@(")
+        memread.addressExpression.accept(this)
+        output(")")
+    }
+
+    override fun visit(memwrite: DirectMemoryWrite) {
+        output("@(")
+        memwrite.addressExpression.accept(this)
+        output(")")
+    }
+
+    override fun visit(addressOf: AddressOf) {
+        output("&")
+        addressOf.identifier.accept(this)
+    }
+
+    override fun visit(inlineAssembly: InlineAssembly) {
+        outputlni("%asm {{")
+        outputln(inlineAssembly.assembly)
+        outputlni("}}")
+    }
+
+    override fun visit(builtinFunctionStatementPlaceholder: BuiltinFunctionStatementPlaceholder) {
+        output(builtinFunctionStatementPlaceholder.name)
+    }
+
+    override fun visit(whenStatement: WhenStatement) {
+        output("when ")
+        whenStatement.condition.accept(this)
+        outputln(" {")
+        scopelevel++
+        whenStatement.choices.forEach { it.accept(this) }
+        scopelevel--
+        outputlni("}")
+    }
+
+    override fun visit(whenChoice: WhenChoice) {
+        val choiceValues = whenChoice.values
+        if(choiceValues==null)
+            outputi("else -> ")
+        else {
+            outputi("")
+            for(value in choiceValues) {
+                value.accept(this)
+                if(value !== choiceValues.last())
+                    output(",")
+            }
+            output(" -> ")
+        }
+        if(whenChoice.statements.statements.size==1)
+            whenChoice.statements.statements.single().accept(this)
+        else
+            whenChoice.statements.accept(this)
+        outputln("")
+    }
+}

compiler/src/prog8/ast/AstToplevel.kt

@@ -0,0 +1,334 @@
+package prog8.ast
+
+import prog8.ast.base.*
+import prog8.ast.expressions.Expression
+import prog8.ast.expressions.IdentifierReference
+import prog8.ast.processing.AstWalker
+import prog8.ast.processing.IAstVisitor
+import prog8.ast.statements.*
+import prog8.functions.BuiltinFunctions
+import java.nio.file.Path
+
+
+interface Node {
+    val position: Position
+    var parent: Node             // will be linked correctly later (late init)
+    fun linkParents(parent: Node)
+
+    fun definingModule(): Module {
+        if(this is Module)
+            return this
+        return findParentNode<Module>(this)!!
+    }
+
+    fun definingSubroutine(): Subroutine?  = findParentNode<Subroutine>(this)
+
+    fun definingScope(): INameScope {
+        val scope = findParentNode<INameScope>(this)
+        if(scope!=null) {
+            return scope
+        }
+        if(this is Label && this.name.startsWith("builtin::")) {
+            return BuiltinFunctionScopePlaceholder
+        }
+        if(this is GlobalNamespace)
+            return this
+        throw FatalAstException("scope missing from $this")
+    }
+
+    fun replaceChildNode(node: Node, replacement: Node)
+}
+
+interface IFunctionCall {
+    var target: IdentifierReference
+    var args: MutableList<Expression>
+}
+
+interface INameScope {
+    val name: String
+    val position: Position
+    val statements: MutableList<Statement>
+    val parent: Node
+
+    fun linkParents(parent: Node)
+
+    fun subScope(name: String): INameScope? {
+        for(stmt in statements) {
+            when(stmt) {
+                // NOTE: if other nodes are introduced that are a scope, or contain subscopes, they must be added here!
+                is ForLoop -> if(stmt.body.name==name) return stmt.body
+                is UntilLoop -> if(stmt.body.name==name) return stmt.body
+                is WhileLoop -> if(stmt.body.name==name) return stmt.body
+                is BranchStatement -> {
+                    if(stmt.truepart.name==name) return stmt.truepart
+                    if(stmt.elsepart.containsCodeOrVars() && stmt.elsepart.name==name) return stmt.elsepart
+                }
+                is IfStatement -> {
+                    if(stmt.truepart.name==name) return stmt.truepart
+                    if(stmt.elsepart.containsCodeOrVars() && stmt.elsepart.name==name) return stmt.elsepart
+                }
+                is WhenStatement -> {
+                    val scope = stmt.choices.firstOrNull { it.statements.name==name }
+                    if(scope!=null)
+                        return scope.statements
+                }
+                is INameScope -> if(stmt.name==name) return stmt
+                else -> {}
+            }
+        }
+        return null
+    }
+
+    fun getLabelOrVariable(name: String): Statement? {
+        // this is called A LOT and could perhaps be optimized a bit more,
+        // but adding a memoization cache didn't make much of a practical runtime difference
+        for (stmt in statements) {
+            if (stmt is VarDecl && stmt.name==name) return stmt
+            if (stmt is Label && stmt.name==name) return stmt
+            if (stmt is AnonymousScope) {
+                val sub = stmt.getLabelOrVariable(name)
+                if(sub!=null)
+                    return sub
+            }
+        }
+        return null
+    }
+
+    fun allDefinedSymbols(): List<Pair<String, Statement>>  {
+        return statements.mapNotNull {
+            when (it) {
+                is Label -> it.name to it
+                is VarDecl -> it.name to it
+                is Subroutine -> it.name to it
+                is Block -> it.name to it
+                else -> null
+            }
+        }
+    }
+
+    fun lookup(scopedName: List<String>, localContext: Node) : Statement? {
+        if(scopedName.size>1) {
+            // a scoped name can a) refer to a member of a struct, or b) refer to a name in another module.
+            // try the struct first.
+            val thing = lookup(scopedName.dropLast(1), localContext) as? VarDecl
+            val struct = thing?.struct
+            if (struct != null) {
+                if(struct.statements.any { (it as VarDecl).name == scopedName.last()}) {
+                    // return ref to the mangled name variable
+                    val mangled = mangledStructMemberName(thing.name, scopedName.last())
+                    return thing.definingScope().getLabelOrVariable(mangled)
+                }
+            }
+
+            // it's a qualified name, look it up from the root of the module's namespace (consider all modules in the program)
+            for(module in localContext.definingModule().program.modules) {
+                var scope: INameScope? = module
+                for(name in scopedName.dropLast(1)) {
+                    scope = scope?.subScope(name)
+                    if(scope==null)
+                        break
+                }
+                if(scope!=null) {
+                    val result = scope.getLabelOrVariable(scopedName.last())
+                    if(result!=null)
+                        return result
+                    return scope.subScope(scopedName.last()) as Statement?
+                }
+            }
+            return null
+        } else {
+            // unqualified name, find the scope the localContext is in, look in that first
+            var statementScope = localContext
+            while(statementScope !is ParentSentinel) {
+                val localScope = statementScope.definingScope()
+                val result = localScope.getLabelOrVariable(scopedName[0])
+                if (result != null)
+                    return result
+                val subscope = localScope.subScope(scopedName[0]) as Statement?
+                if (subscope != null)
+                    return subscope
+                // not found in this scope, look one higher up
+                statementScope = statementScope.parent
+            }
+            return null
+        }
+    }
+
+    fun containsCodeOrVars() = statements.any { it !is Directive || it.directive == "%asminclude" || it.directive == "%asm"}
+    fun containsNoVars() = statements.all { it !is VarDecl }
+    fun containsNoCodeNorVars() = !containsCodeOrVars()
+
+    fun remove(stmt: Statement) {
+        if(!statements.remove(stmt))
+            throw FatalAstException("stmt to remove wasn't found in scope")
+    }
+
+    fun getAllLabels(label: String): List<Label> {
+        val result = mutableListOf<Label>()
+
+        fun find(scope: INameScope) {
+            scope.statements.forEach {
+                when(it) {
+                    is Label -> result.add(it)
+                    is INameScope -> find(it)
+                    is IfStatement -> {
+                        find(it.truepart)
+                        find(it.elsepart)
+                    }
+                    is UntilLoop -> find(it.body)
+                    is RepeatLoop -> find(it.body)
+                    is WhileLoop -> find(it.body)
+                    is WhenStatement -> it.choices.forEach { choice->find(choice.statements) }
+                    else -> { /* do nothing */ }
+                }
+            }
+        }
+
+        find(this)
+        return result
+    }
+
+    fun nextSibling(stmt: Statement): Statement? {
+        val nextIdx = statements.indexOfFirst { it===stmt } + 1
+        return if(nextIdx < statements.size)
+            statements[nextIdx]
+        else
+            null
+    }
+}
+
+interface IAssignable {
+    // just a tag for now
+}
+
+
+/*********** Everything starts from here, the Program; zero or more modules *************/
+
+class Program(val name: String, val modules: MutableList<Module>): Node {
+    val namespace = GlobalNamespace(modules)
+
+    val definedLoadAddress: Int
+        get() = modules.first().loadAddress
+
+    var actualLoadAddress: Int = 0
+
+    fun entrypoint(): Subroutine? {
+        val mainBlocks = allBlocks().filter { it.name=="main" }
+        if(mainBlocks.size > 1)
+            throw FatalAstException("more than one 'main' block")
+        return if(mainBlocks.isEmpty()) {
+            null
+        } else {
+            mainBlocks[0].subScope("start") as Subroutine?
+        }
+    }
+
+    fun allBlocks(): List<Block> = modules.flatMap { it.statements.filterIsInstance<Block>() }
+
+    override val position: Position = Position.DUMMY
+    override var parent: Node
+        get() = throw FatalAstException("program has no parent")
+        set(value) = throw FatalAstException("can't set parent of program")
+
+    override fun linkParents(parent: Node) {
+        modules.forEach {
+            it.linkParents(this)
+        }
+    }
+
+    override fun replaceChildNode(node: Node, replacement: Node) {
+        require(node is Module && replacement is Module)
+        val idx = modules.indexOfFirst { it===node }
+        modules[idx] = replacement
+        replacement.parent = this
+    }
+}
+
+class Module(override val name: String,
+             override var statements: MutableList<Statement>,
+             override val position: Position,
+             val isLibraryModule: Boolean,
+             val source: Path) : Node, INameScope {
+
+    override lateinit var parent: Node
+    lateinit var program: Program
+    val importedBy = mutableListOf<Module>()
+    val imports = mutableSetOf<Module>()
+
+    var loadAddress: Int = 0        // can be set with the %address directive
+
+    override fun linkParents(parent: Node) {
+        this.parent = parent
+        statements.forEach {it.linkParents(this)}
+    }
+
+    override fun definingScope(): INameScope = program.namespace
+    override fun replaceChildNode(node: Node, replacement: Node) {
+        require(node is Statement && replacement is Statement)
+        val idx = statements.indexOfFirst { it===node }
+        statements[idx] = replacement
+        replacement.parent = this
+    }
+
+    override fun toString() = "Module(name=$name, pos=$position, lib=$isLibraryModule)"
+
+    fun accept(visitor: IAstVisitor) = visitor.visit(this)
+    fun accept(visitor: AstWalker, parent: Node) = visitor.visit(this, parent)
+}
+
+
+class GlobalNamespace(val modules: List<Module>): Node, INameScope {
+    override val name = "<<<global>>>"
+    override val position = Position("<<<global>>>", 0, 0, 0)
+    override val statements = mutableListOf<Statement>()
+    override var parent: Node = ParentSentinel
+
+    override fun linkParents(parent: Node) {
+        modules.forEach { it.linkParents(this) }
+    }
+
+    override fun replaceChildNode(node: Node, replacement: Node) {
+        throw FatalAstException("cannot replace anything in the namespace")
+    }
+
+    override fun lookup(scopedName: List<String>, localContext: Node): Statement? {
+        if (scopedName.size == 1 && scopedName[0] in BuiltinFunctions) {
+            // builtin functions always exist, return a dummy localContext for them
+            val builtinPlaceholder = Label("builtin::${scopedName.last()}", localContext.position)
+            builtinPlaceholder.parent = ParentSentinel
+            return builtinPlaceholder
+        }
+
+        if(scopedName.size>1) {
+            // a scoped name can a) refer to a member of a struct, or b) refer to a name in another module.
+            // try the struct first.
+            val thing = lookup(scopedName.dropLast(1), localContext) as? VarDecl
+            val struct = thing?.struct
+            if (struct != null) {
+                if(struct.statements.any { (it as VarDecl).name == scopedName.last()}) {
+                    // return ref to the mangled name variable
+                    val mangled = mangledStructMemberName(thing.name, scopedName.last())
+                    return thing.definingScope().getLabelOrVariable(mangled)
+                }
+            }
+        }
+        // lookup something from the module.
+        return when (val stmt = localContext.definingModule().lookup(scopedName, localContext)) {
+            is Label, is VarDecl, is Block, is Subroutine, is StructDecl -> stmt
+            null -> null
+            else -> throw SyntaxError("invalid identifier target type", stmt.position)
+        }
+    }
+}
+
+object BuiltinFunctionScopePlaceholder : INameScope {
+    override val name = "<<builtin-functions-scope-placeholder>>"
+    override val position = Position("<<placeholder>>", 0, 0, 0)
+    override var statements = mutableListOf<Statement>()
+    override var parent: Node = ParentSentinel
+    override fun linkParents(parent: Node) {}
+}
+
+
+// prefix for struct member variables
+internal fun mangledStructMemberName(varName: String, memberName: String) = "prog8struct_${varName}_$memberName"

compiler/src/prog8/ast/ImportedAstChecker.kt

@@ -1,43 +0,0 @@
-package prog8.ast
-
-
-/**
- * Checks that are specific for imported modules.
- */
-
-fun Module.checkImportedValid() {
-    val checker = ImportedAstChecker()
-    this.linkParents()
-    this.process(checker)
-    printErrors(checker.result(), name)
-}
-
-
-private class ImportedAstChecker : IAstProcessor {
-    private val checkResult: MutableList<SyntaxError> = mutableListOf()
-
-    fun result(): List<SyntaxError> {
-        return checkResult
-    }
-
-    /**
-     * Module check: most global directives don't apply for imported modules
-     */
-    override fun process(module: Module) {
-        super.process(module)
-        val newStatements : MutableList<IStatement> = mutableListOf()
-
-        val moduleLevelDirectives = listOf("%output", "%launcher", "%zeropage", "%zpreserved", "%address")
-        for (sourceStmt in module.statements) {
-            val stmt = sourceStmt.process(this)
-            if(stmt is Directive && stmt.parent is Module) {
-                if(stmt.directive in moduleLevelDirectives) {
-                    printWarning("ignoring module directive because it was imported", stmt.position, stmt.directive)
-                    continue
-                }
-            }
-            newStatements.add(stmt)
-        }
-        module.statements = newStatements
-    }
-}

compiler/src/prog8/ast/StmtReorderer.kt

@@ -1,247 +0,0 @@
-package prog8.ast
-
-import prog8.compiler.HeapValues
-
-fun Module.reorderStatements(namespace: INameScope, heap: HeapValues) {
-    val initvalueCreator = VarInitValueCreator()
-    this.process(initvalueCreator)
-
-    val checker = StatementReorderer(namespace, heap)
-    this.process(checker)
-}
-
-const val initvarsSubName="prog8_init_vars"    // the name of the subroutine that should be called for every block to initialize its variables
-
-
-private class StatementReorderer(private val namespace: INameScope, private val heap: HeapValues): IAstProcessor {
-    // Reorders the statements in a way the compiler needs.
-    // - 'main' block must be the very first statement UNLESS it has an address set.
-    // - blocks are ordered by address, where blocks without address are put at the end.
-    // - in every scope:
-    //      -- the directives '%output', '%launcher', '%zeropage', '%zpreserved', '%address' and '%option' will come first.
-    //      -- all vardecls then follow.
-    //      -- the remaining statements then follow in their original order.
-    //
-    // - the 'start' subroutine in the 'main' block will be moved to the top immediately following the directives.
-    // - all other subroutines will be moved to the end of their block.
-
-    private val directivesToMove = setOf("%output", "%launcher", "%zeropage", "%zpreserved", "%address", "%option")
-
-    override fun process(module: Module) {
-        super.process(module)
-
-        val (blocks, other) = module.statements.partition { it is Block }
-        module.statements = other.asSequence().plus(blocks.sortedBy { (it as Block).address ?: Int.MAX_VALUE }).toMutableList()
-
-        val mainBlock = module.statements.single { it is Block && it.name=="main" }
-        if((mainBlock as Block).address==null) {
-            module.statements.remove(mainBlock)
-            module.statements.add(0, mainBlock)
-        }
-        val varDecls = module.statements.filterIsInstance<VarDecl>()
-        module.statements.removeAll(varDecls)
-        module.statements.addAll(0, varDecls)
-
-        val directives = module.statements.filter {it is Directive && it.directive in directivesToMove}
-        module.statements.removeAll(directives)
-        module.statements.addAll(0, directives)
-
-        // TODO make sure user-defined blocks come BEFORE library blocks
-
-        sortConstantAssignments(module.statements)
-    }
-
-    override fun process(block: Block): IStatement {
-
-        val subroutines = block.statements.filterIsInstance<Subroutine>()
-        var numSubroutinesAtEnd = 0
-        // move all subroutines to the end of the block
-        for (subroutine in subroutines) {
-            if(subroutine.name!="start" || block.name!="main") {
-                block.statements.remove(subroutine)
-                block.statements.add(subroutine)
-            }
-            numSubroutinesAtEnd++
-        }
-        // move the "start" subroutine to the top
-        if(block.name=="main") {
-            block.statements.singleOrNull { it is Subroutine && it.name == "start" } ?.let {
-                block.statements.remove(it)
-                block.statements.add(0, it)
-                numSubroutinesAtEnd--
-            }
-        }
-
-        // make sure there is a 'return' in front of the first subroutine
-        // (if it isn't the first statement in the block itself, and isn't the program's entrypoint)
-        if(numSubroutinesAtEnd>0 && block.statements.size > (numSubroutinesAtEnd+1)) {
-            val firstSub = block.statements[block.statements.size - numSubroutinesAtEnd] as Subroutine
-            if(firstSub.name != "start" && block.name != "main") {
-                val stmtBeforeFirstSub = block.statements[block.statements.size - numSubroutinesAtEnd - 1]
-                if (stmtBeforeFirstSub !is Return
-                        && stmtBeforeFirstSub !is Jump
-                        && stmtBeforeFirstSub !is Subroutine
-                        && stmtBeforeFirstSub !is BuiltinFunctionStatementPlaceholder) {
-                    val ret = Return(emptyList(), stmtBeforeFirstSub.position)
-                    ret.linkParents(block)
-                    block.statements.add(block.statements.size - numSubroutinesAtEnd, ret)
-                }
-            }
-        }
-
-        val varDecls = block.statements.filter { it is VarDecl }
-        block.statements.removeAll(varDecls)
-        block.statements.addAll(0, varDecls)
-        val directives = block.statements.filter {it is Directive && it.directive in directivesToMove}
-        block.statements.removeAll(directives)
-        block.statements.addAll(0, directives)
-
-        sortConstantAssignments(block.statements)
-
-        val varInits = block.statements.withIndex().filter { it.value is VariableInitializationAssignment }
-        if(varInits.isNotEmpty()) {
-            val statements = varInits.map{it.value}.toMutableList()
-            val varInitSub = Subroutine(initvarsSubName, emptyList(), emptyList(), emptyList(), emptyList(),
-                    emptySet(), null, false, statements, block.position)
-            varInitSub.linkParents(block)
-            block.statements.add(varInitSub)
-
-            // remove the varinits from the block's statements
-            for(index in varInits.map{it.index}.reversed())
-                block.statements.removeAt(index)
-        }
-
-        return super.process(block)
-    }
-
-    override fun process(subroutine: Subroutine): IStatement {
-        super.process(subroutine)
-
-        sortConstantAssignments(subroutine.statements)
-
-        val varDecls = subroutine.statements.filterIsInstance<VarDecl>()
-        subroutine.statements.removeAll(varDecls)
-        subroutine.statements.addAll(0, varDecls)
-        val directives = subroutine.statements.filter {it is Directive && it.directive in directivesToMove}
-        subroutine.statements.removeAll(directives)
-        subroutine.statements.addAll(0, directives)
-
-        if(subroutine.returntypes.isEmpty()) {
-            // add the implicit return statement at the end (if it's not there yet), but only if it's not a kernel routine.
-            // and if an assembly block doesn't contain a rts/rti
-            if(subroutine.asmAddress==null && subroutine.amountOfRtsInAsm()==0) {
-                if (subroutine.statements.lastOrNull {it !is VarDecl} !is Return) {
-                    val returnStmt = Return(emptyList(), subroutine.position)
-                    returnStmt.linkParents(subroutine)
-                    subroutine.statements.add(returnStmt)
-                }
-            }
-        }
-
-        return subroutine
-    }
-
-    override fun process(scope: AnonymousScope): AnonymousScope {
-        scope.statements = scope.statements.map { it.process(this)}.toMutableList()
-        sortConstantAssignments(scope.statements)
-        return scope
-    }
-
-    private fun sortConstantAssignments(statements: MutableList<IStatement>) {
-        // sort assignments by datatype and value, so multiple initializations with the same value can be optimized (to load the value just once)
-        val result = mutableListOf<IStatement>()
-        val stmtIter = statements.iterator()
-        for(stmt in stmtIter) {
-            if(stmt is Assignment) {
-                val constval = stmt.value.constValue(namespace, heap)
-                if(constval!=null) {
-                    val (sorted, trailing) = sortConstantAssignmentSequence(stmt, stmtIter)
-                    result.addAll(sorted)
-                    if(trailing!=null)
-                        result.add(trailing)
-                }
-                else
-                    result.add(stmt)
-            }
-            else
-                result.add(stmt)
-        }
-        statements.clear()
-        statements.addAll(result)
-    }
-
-    private fun sortConstantAssignmentSequence(first: Assignment, stmtIter: MutableIterator<IStatement>): Pair<List<Assignment>, IStatement?> {
-        val sequence= mutableListOf(first)
-        var trailing: IStatement? = null
-        while(stmtIter.hasNext()) {
-            val next = stmtIter.next()
-            if(next is Assignment) {
-                val constValue = next.value.constValue(namespace, heap)
-                if(constValue==null) {
-                    trailing = next
-                    break
-                }
-                sequence.add(next)
-            }
-            else {
-                trailing=next
-                break
-            }
-        }
-        val sorted = sequence.sortedWith(compareBy({it.value.resultingDatatype(namespace, heap)}, {it.singleTarget?.shortString(true)}))
-        return Pair(sorted, trailing)
-    }
-
-}
-
-
-private class VarInitValueCreator: IAstProcessor {
-    // Replace the var decl with an assignment and add a new vardecl with the default constant value.
-    // This makes sure the variables get reset to the intended value on a next run of the program.
-    // Variable decls without a value don't get this treatment, which means they retain the last
-    // value they had when restarting the program.
-    // This is done in a separate step because it interferes with the namespace lookup of symbols
-    // in other ast processors.
-
-    private val vardeclsToAdd = mutableMapOf<INameScope, MutableList<VarDecl>>()
-
-    override fun process(module: Module) {
-        super.process(module)
-
-        // add any new vardecls to the various scopes
-        for(decl in vardeclsToAdd)
-            for(d in decl.value) {
-                d.linkParents(decl.key as Node)
-                decl.key.statements.add(0, d)
-            }
-    }
-
-    override fun process(decl: VarDecl): IStatement {
-        super.process(decl)
-        if(decl.type!=VarDeclType.VAR || decl.value==null)
-            return decl
-
-        if(decl.datatype in NumericDatatypes) {
-            val scope = decl.definingScope()
-            if(scope !in vardeclsToAdd)
-                vardeclsToAdd[scope] = mutableListOf()
-            vardeclsToAdd[scope]!!.add(decl.asDefaultValueDecl(null))
-            val declvalue = decl.value!!
-            val value =
-                    if(declvalue is LiteralValue) {
-                        val converted = declvalue.intoDatatype(decl.datatype)
-                        converted ?: declvalue
-                    }
-                    else
-                        declvalue
-            return VariableInitializationAssignment(
-                    AssignTarget(null, IdentifierReference(decl.scopedname.split("."), decl.position), null, null, decl.position),
-                    null,
-                    value,
-                    decl.position
-            )
-        }
-        return decl
-    }
-
-}

compiler/src/prog8/ast/antlr/Antr2Kotlin.kt

@@ -0,0 +1,675 @@
+package prog8.ast.antlr
+
+import org.antlr.v4.runtime.IntStream
+import org.antlr.v4.runtime.ParserRuleContext
+import org.antlr.v4.runtime.tree.TerminalNode
+import prog8.ast.Module
+import prog8.ast.base.*
+import prog8.ast.expressions.*
+import prog8.ast.statements.*
+import prog8.compiler.target.CompilationTarget
+import prog8.parser.CustomLexer
+import prog8.parser.prog8Parser
+import java.io.CharConversionException
+import java.io.File
+import java.nio.file.Path
+
+
+/***************** Antlr Extension methods to create AST ****************/
+
+private data class NumericLiteral(val number: Number, val datatype: DataType)
+
+internal fun prog8Parser.ModuleContext.toAst(name: String, isLibrary: Boolean, source: Path) : Module {
+    val nameWithoutSuffix = if(name.endsWith(".p8")) name.substringBeforeLast('.') else name
+    val directives = this.directive().map { it.toAst() }
+    val blocks = this.block().map { it.toAst(isLibrary) }
+    return Module(nameWithoutSuffix, (directives + blocks).toMutableList(), toPosition(), isLibrary, source)
+}
+
+private fun ParserRuleContext.toPosition() : Position {
+    val customTokensource = this.start.tokenSource as? CustomLexer
+    val filename =
+            when {
+                customTokensource!=null -> customTokensource.modulePath.fileName.toString()
+                start.tokenSource.sourceName == IntStream.UNKNOWN_SOURCE_NAME -> "@internal@"
+                else -> File(start.inputStream.sourceName).name
+            }
+    // note: be ware of TAB characters in the source text, they count as 1 column...
+    return Position(filename, start.line, start.charPositionInLine, stop.charPositionInLine + stop.text.length)
+}
+
+private fun prog8Parser.BlockContext.toAst(isInLibrary: Boolean) : Statement {
+    val blockstatements = block_statement().map {
+        when {
+            it.variabledeclaration()!=null -> it.variabledeclaration().toAst()
+            it.subroutinedeclaration()!=null -> it.subroutinedeclaration().toAst()
+            it.directive()!=null -> it.directive().toAst()
+            it.inlineasm()!=null -> it.inlineasm().toAst()
+            else -> throw FatalAstException("weird block statement $it")
+        }
+    }
+    return Block(identifier().text, integerliteral()?.toAst()?.number?.toInt(), blockstatements.toMutableList(), isInLibrary, toPosition())
+}
+
+private fun prog8Parser.Statement_blockContext.toAst(): MutableList<Statement> =
+        statement().asSequence().map { it.toAst() }.toMutableList()
+
+private fun prog8Parser.VariabledeclarationContext.toAst() : Statement {
+    vardecl()?.let { return it.toAst() }
+
+    varinitializer()?.let {
+        val vd = it.vardecl()
+        return VarDecl(
+                VarDeclType.VAR,
+                vd.datatype()?.toAst() ?: DataType.STRUCT,
+                if (vd.ZEROPAGE() != null) ZeropageWish.PREFER_ZEROPAGE else ZeropageWish.DONTCARE,
+                vd.arrayindex()?.toAst(),
+                vd.varname.text,
+                null,
+                it.expression().toAst(),
+                vd.ARRAYSIG() != null || vd.arrayindex() != null,
+                false,
+                it.toPosition()
+        )
+    }
+
+    structvarinitializer()?.let {
+        val vd = it.structvardecl()
+        return VarDecl(
+                VarDeclType.VAR,
+                DataType.STRUCT,
+                ZeropageWish.NOT_IN_ZEROPAGE,
+                null,
+                vd.varname.text,
+                vd.structname.text,
+                it.expression().toAst(),
+                isArray = false,
+                autogeneratedDontRemove = false,
+                position = it.toPosition()
+        )
+    }
+
+    structvardecl()?.let {
+        return VarDecl(
+                VarDeclType.VAR,
+                DataType.STRUCT,
+                ZeropageWish.NOT_IN_ZEROPAGE,
+                null,
+                it.varname.text,
+                it.structname.text,
+                null,
+                isArray = false,
+                autogeneratedDontRemove = false,
+                position = it.toPosition()
+        )
+    }
+
+    constdecl()?.let {
+        val cvarinit = it.varinitializer()
+        val vd = cvarinit.vardecl()
+        return VarDecl(
+                VarDeclType.CONST,
+                vd.datatype()?.toAst() ?: DataType.STRUCT,
+                if (vd.ZEROPAGE() != null) ZeropageWish.PREFER_ZEROPAGE else ZeropageWish.DONTCARE,
+                vd.arrayindex()?.toAst(),
+                vd.varname.text,
+                null,
+                cvarinit.expression().toAst(),
+                vd.ARRAYSIG() != null || vd.arrayindex() != null,
+                false,
+                cvarinit.toPosition()
+        )
+    }
+
+    memoryvardecl()?.let {
+        val mvarinit = it.varinitializer()
+        val vd = mvarinit.vardecl()
+        return VarDecl(
+                VarDeclType.MEMORY,
+                vd.datatype()?.toAst() ?: DataType.STRUCT,
+                if (vd.ZEROPAGE() != null) ZeropageWish.PREFER_ZEROPAGE else ZeropageWish.DONTCARE,
+                vd.arrayindex()?.toAst(),
+                vd.varname.text,
+                null,
+                mvarinit.expression().toAst(),
+                vd.ARRAYSIG() != null || vd.arrayindex() != null,
+                false,
+                mvarinit.toPosition()
+        )
+    }
+
+    structdecl()?.let {
+        return StructDecl(it.identifier().text,
+                it.vardecl().map { vd->vd.toAst() }.toMutableList(),
+                toPosition())
+    }
+
+    throw FatalAstException("weird variable decl $this")
+}
+
+private fun prog8Parser.SubroutinedeclarationContext.toAst() : Subroutine {
+    return when {
+        subroutine()!=null -> subroutine().toAst()
+        asmsubroutine()!=null -> asmsubroutine().toAst()
+        romsubroutine()!=null -> romsubroutine().toAst()
+        else -> throw FatalAstException("weird subroutine decl $this")
+    }
+}
+
+private fun prog8Parser.StatementContext.toAst() : Statement {
+    val vardecl = variabledeclaration()?.toAst()
+    if(vardecl!=null) return vardecl
+
+    assignment()?.let {
+        return Assignment(it.assign_target().toAst(), it.expression().toAst(), it.toPosition())
+    }
+
+    augassignment()?.let {
+        // replace A += X  with  A = A + X
+        val target = it.assign_target().toAst()
+        val oper = it.operator.text.substringBefore('=')
+        val expression = BinaryExpression(target.toExpression(), oper, it.expression().toAst(), it.expression().toPosition())
+        return Assignment(it.assign_target().toAst(), expression, it.toPosition())
+    }
+
+    postincrdecr()?.let {
+        return PostIncrDecr(it.assign_target().toAst(), it.operator.text, it.toPosition())
+    }
+
+    val directive = directive()?.toAst()
+    if(directive!=null) return directive
+
+    val label = labeldef()?.toAst()
+    if(label!=null) return label
+
+    val jump = unconditionaljump()?.toAst()
+    if(jump!=null) return jump
+
+    val fcall = functioncall_stmt()?.toAst()
+    if(fcall!=null) return fcall
+
+    val ifstmt = if_stmt()?.toAst()
+    if(ifstmt!=null) return ifstmt
+
+    val returnstmt = returnstmt()?.toAst()
+    if(returnstmt!=null) return returnstmt
+
+    val subroutine = subroutinedeclaration()?.toAst()
+    if(subroutine!=null) return subroutine
+
+    val asm = inlineasm()?.toAst()
+    if(asm!=null) return asm
+
+    val branchstmt = branch_stmt()?.toAst()
+    if(branchstmt!=null) return branchstmt
+
+    val forloop = forloop()?.toAst()
+    if(forloop!=null) return forloop
+
+    val untilloop = untilloop()?.toAst()
+    if(untilloop!=null) return untilloop
+
+    val whileloop = whileloop()?.toAst()
+    if(whileloop!=null) return whileloop
+
+    val repeatloop = repeatloop()?.toAst()
+    if(repeatloop!=null) return repeatloop
+
+    val breakstmt = breakstmt()?.toAst()
+    if(breakstmt!=null) return breakstmt
+
+    val whenstmt = whenstmt()?.toAst()
+    if(whenstmt!=null) return whenstmt
+
+    throw FatalAstException("unprocessed source text (are we missing ast conversion rules for parser elements?): $text")
+}
+
+private fun prog8Parser.AsmsubroutineContext.toAst(): Subroutine {
+    val subdecl = asmsub_decl().toAst()
+    val statements = statement_block()?.toAst() ?: mutableListOf()
+    return Subroutine(subdecl.name, subdecl.parameters, subdecl.returntypes,
+            subdecl.asmParameterRegisters, subdecl.asmReturnvaluesRegisters,
+            subdecl.asmClobbers, null, true, statements, toPosition())
+}
+
+private fun prog8Parser.RomsubroutineContext.toAst(): Subroutine {
+    val subdecl = asmsub_decl().toAst()
+    val address = integerliteral().toAst().number.toInt()
+    return Subroutine(subdecl.name, subdecl.parameters, subdecl.returntypes,
+            subdecl.asmParameterRegisters, subdecl.asmReturnvaluesRegisters,
+            subdecl.asmClobbers, address, true, mutableListOf(), toPosition())
+}
+
+private class AsmsubDecl(val name: String,
+                         val parameters: List<SubroutineParameter>,
+                         val returntypes: List<DataType>,
+                         val asmParameterRegisters: List<RegisterOrStatusflag>,
+                         val asmReturnvaluesRegisters: List<RegisterOrStatusflag>,
+                         val asmClobbers: Set<CpuRegister>)
+
+private fun prog8Parser.Asmsub_declContext.toAst(): AsmsubDecl {
+    val name = identifier().text
+    val params = asmsub_params()?.toAst() ?: emptyList()
+    val returns = asmsub_returns()?.toAst() ?: emptyList()
+    val clobbers = asmsub_clobbers()?.clobber()?.toAst() ?: emptySet()
+    val normalParameters = params.map { SubroutineParameter(it.name, it.type, it.position) }
+    val normalReturntypes = returns.map { it.type }
+    val paramRegisters = params.map { RegisterOrStatusflag(it.registerOrPair, it.statusflag, it.stack) }
+    val returnRegisters = returns.map { RegisterOrStatusflag(it.registerOrPair, it.statusflag, it.stack) }
+    return AsmsubDecl(name, normalParameters, normalReturntypes, paramRegisters, returnRegisters, clobbers)
+}
+
+private class AsmSubroutineParameter(name: String,
+                                     type: DataType,
+                                     val registerOrPair: RegisterOrPair?,
+                                     val statusflag: Statusflag?,
+                                     val stack: Boolean,
+                                     position: Position) : SubroutineParameter(name, type, position)
+
+private class AsmSubroutineReturn(val type: DataType,
+                                  val registerOrPair: RegisterOrPair?,
+                                  val statusflag: Statusflag?,
+                                  val stack: Boolean,
+                                  val position: Position)
+
+private fun prog8Parser.Asmsub_returnsContext.toAst(): List<AsmSubroutineReturn>
+        = asmsub_return().map {
+            val register = it.identifier()?.toAst()
+            var registerorpair: RegisterOrPair? = null
+            var statusregister: Statusflag? = null
+            if(register!=null) {
+                when (val name = register.nameInSource.single()) {
+                    in RegisterOrPair.names -> registerorpair = RegisterOrPair.valueOf(name)
+                    in Statusflag.names -> statusregister = Statusflag.valueOf(name)
+                    else -> throw FatalAstException("invalid register or status flag in $it")
+                }
+            }
+            AsmSubroutineReturn(
+                    it.datatype().toAst(),
+                    registerorpair,
+                    statusregister,
+                    !it.stack?.text.isNullOrEmpty(), toPosition())
+        }
+
+private fun prog8Parser.Asmsub_paramsContext.toAst(): List<AsmSubroutineParameter>
+        = asmsub_param().map {
+    val vardecl = it.vardecl()
+    val datatype = vardecl.datatype()?.toAst() ?: DataType.STRUCT
+    val register = it.identifier()?.toAst()
+    var registerorpair: RegisterOrPair? = null
+    var statusregister: Statusflag? = null
+    if(register!=null) {
+        when (val name = register.nameInSource.single()) {
+            in RegisterOrPair.names -> registerorpair = RegisterOrPair.valueOf(name)
+            in Statusflag.names -> statusregister = Statusflag.valueOf(name)
+            else -> throw FatalAstException("invalid register or status flag '$name'")
+        }
+    }
+    AsmSubroutineParameter(vardecl.varname.text, datatype, registerorpair, statusregister,
+            !it.stack?.text.isNullOrEmpty(), toPosition())
+}
+
+private fun prog8Parser.Functioncall_stmtContext.toAst(): Statement {
+    val void = this.VOID() != null
+    val location = scoped_identifier().toAst()
+    return if(expression_list() == null)
+        FunctionCallStatement(location, mutableListOf(), void, toPosition())
+    else
+        FunctionCallStatement(location, expression_list().toAst().toMutableList(), void, toPosition())
+}
+
+private fun prog8Parser.FunctioncallContext.toAst(): FunctionCall {
+    val location = scoped_identifier().toAst()
+    return if(expression_list() == null)
+        FunctionCall(location, mutableListOf(), toPosition())
+    else
+        FunctionCall(location, expression_list().toAst().toMutableList(), toPosition())
+}
+
+private fun prog8Parser.InlineasmContext.toAst() =
+        InlineAssembly(INLINEASMBLOCK().text, toPosition())
+
+private fun prog8Parser.ReturnstmtContext.toAst() : Return {
+    return Return(expression()?.toAst(), toPosition())
+}
+
+private fun prog8Parser.UnconditionaljumpContext.toAst(): Jump {
+    val address = integerliteral()?.toAst()?.number?.toInt()
+    val identifier = scoped_identifier()?.toAst()
+    return Jump(address, identifier, null, toPosition())
+}
+
+private fun prog8Parser.LabeldefContext.toAst(): Statement =
+        Label(children[0].text, toPosition())
+
+private fun prog8Parser.SubroutineContext.toAst() : Subroutine {
+    return Subroutine(identifier().text,
+            sub_params()?.toAst() ?: emptyList(),
+            sub_return_part()?.toAst() ?: emptyList(),
+            emptyList(),
+            emptyList(),
+            emptySet(),
+            null,
+            false,
+            statement_block()?.toAst() ?: mutableListOf(),
+            toPosition())
+}
+
+private fun prog8Parser.Sub_return_partContext.toAst(): List<DataType> {
+    val returns = sub_returns() ?: return emptyList()
+    return returns.datatype().map { it.toAst() }
+}
+
+private fun prog8Parser.Sub_paramsContext.toAst(): List<SubroutineParameter> =
+        vardecl().map {
+            val datatype = it.datatype()?.toAst() ?: DataType.STRUCT
+            SubroutineParameter(it.varname.text, datatype, it.toPosition())
+        }
+
+private fun prog8Parser.Assign_targetContext.toAst() : AssignTarget {
+    val identifier = scoped_identifier()
+    return when {
+        identifier!=null -> AssignTarget(identifier.toAst(), null, null, toPosition())
+        arrayindexed()!=null -> AssignTarget(null, arrayindexed().toAst(), null, toPosition())
+        directmemory()!=null -> AssignTarget(null, null, DirectMemoryWrite(directmemory().expression().toAst(), toPosition()), toPosition())
+        else -> AssignTarget(scoped_identifier()?.toAst(), null, null, toPosition())
+    }
+}
+
+private fun prog8Parser.ClobberContext.toAst() : Set<CpuRegister> {
+    val names = this.identifier().map { it.toAst().nameInSource.single() }
+    return names.map { CpuRegister.valueOf(it) }.toSet()
+}
+
+private fun prog8Parser.DatatypeContext.toAst() = DataType.valueOf(text.toUpperCase())
+
+private fun prog8Parser.ArrayindexContext.toAst() : ArrayIndex =
+        ArrayIndex(expression().toAst(), toPosition())
+
+private fun prog8Parser.DirectiveContext.toAst() : Directive =
+        Directive(directivename.text, directivearg().map { it.toAst() }, toPosition())
+
+private fun prog8Parser.DirectiveargContext.toAst() : DirectiveArg {
+    val str = stringliteral()
+    if(str?.ALT_STRING_ENCODING() != null)
+        throw AstException("${toPosition()} can't use alternate string encodings for directive arguments")
+
+    return DirectiveArg(stringliteral()?.text, identifier()?.text, integerliteral()?.toAst()?.number?.toInt(), toPosition())
+}
+
+private fun prog8Parser.IntegerliteralContext.toAst(): NumericLiteral {
+    fun makeLiteral(text: String, radix: Int, forceWord: Boolean): NumericLiteral {
+        val integer: Int
+        var datatype = DataType.UBYTE
+        when (radix) {
+            10 -> {
+                integer = try {
+                    text.toInt()
+                } catch(x: NumberFormatException) {
+                    throw AstException("${toPosition()} invalid decimal literal ${x.message}")
+                }
+                datatype = when(integer) {
+                    in 0..255 -> DataType.UBYTE
+                    in -128..127 -> DataType.BYTE
+                    in 0..65535 -> DataType.UWORD
+                    in -32768..32767 -> DataType.WORD
+                    else -> DataType.FLOAT
+                }
+            }
+            2 -> {
+                if(text.length>8)
+                    datatype = DataType.UWORD
+                try {
+                    integer = text.toInt(2)
+                } catch(x: NumberFormatException) {
+                    throw AstException("${toPosition()} invalid binary literal ${x.message}")
+                }
+            }
+            16 -> {
+                if(text.length>2)
+                    datatype = DataType.UWORD
+                try {
+                    integer = text.toInt(16)
+                } catch(x: NumberFormatException) {
+                    throw AstException("${toPosition()} invalid hexadecimal literal ${x.message}")
+                }
+            }
+            else -> throw FatalAstException("invalid radix")
+        }
+        return NumericLiteral(integer, if (forceWord) DataType.UWORD else datatype)
+    }
+    val terminal: TerminalNode = children[0] as TerminalNode
+    val integerPart = this.intpart.text
+    return when (terminal.symbol.type) {
+        prog8Parser.DEC_INTEGER -> makeLiteral(integerPart, 10, wordsuffix()!=null)
+        prog8Parser.HEX_INTEGER -> makeLiteral(integerPart.substring(1), 16, wordsuffix()!=null)
+        prog8Parser.BIN_INTEGER -> makeLiteral(integerPart.substring(1), 2, wordsuffix()!=null)
+        else -> throw FatalAstException(terminal.text)
+    }
+}
+
+private fun prog8Parser.ExpressionContext.toAst() : Expression {
+
+    val litval = literalvalue()
+    if(litval!=null) {
+        val booleanlit = litval.booleanliteral()?.toAst()
+        return if(booleanlit!=null) {
+            NumericLiteralValue.fromBoolean(booleanlit, litval.toPosition())
+        }
+        else {
+            val intLit = litval.integerliteral()?.toAst()
+            when {
+                intLit!=null -> when(intLit.datatype) {
+                    DataType.UBYTE -> NumericLiteralValue(DataType.UBYTE, intLit.number.toShort(), litval.toPosition())
+                    DataType.BYTE -> NumericLiteralValue(DataType.BYTE, intLit.number.toShort(), litval.toPosition())
+                    DataType.UWORD -> NumericLiteralValue(DataType.UWORD, intLit.number.toInt(), litval.toPosition())
+                    DataType.WORD -> NumericLiteralValue(DataType.WORD, intLit.number.toInt(), litval.toPosition())
+                    DataType.FLOAT -> NumericLiteralValue(DataType.FLOAT, intLit.number.toDouble(), litval.toPosition())
+                    else -> throw FatalAstException("invalid datatype for numeric literal")
+                }
+                litval.floatliteral()!=null -> NumericLiteralValue(DataType.FLOAT, litval.floatliteral().toAst(), litval.toPosition())
+                litval.stringliteral()!=null -> litval.stringliteral().toAst()
+                litval.charliteral()!=null -> {
+                    try {
+                        val cc=litval.charliteral()
+                        NumericLiteralValue(DataType.UBYTE, CompilationTarget.encodeString(
+                                unescape(litval.charliteral().SINGLECHAR().text, litval.toPosition()),
+                                litval.charliteral().ALT_STRING_ENCODING()!=null)[0], litval.toPosition())
+                    } catch (ce: CharConversionException) {
+                        throw SyntaxError(ce.message ?: ce.toString(), litval.toPosition())
+                    }
+                }
+                litval.arrayliteral()!=null -> {
+                    val array = litval.arrayliteral().toAst()
+                    // the actual type of the arraysize can not yet be determined here (missing namespace & heap)
+                    // the ConstantFold takes care of that and converts the type if needed.
+                    ArrayLiteralValue(InferredTypes.InferredType.unknown(), array, position = litval.toPosition())
+                }
+                else -> throw FatalAstException("invalid parsed literal")
+            }
+        }
+    }
+
+    if(scoped_identifier()!=null)
+        return scoped_identifier().toAst()
+
+    if(bop!=null)
+        return BinaryExpression(left.toAst(), bop.text, right.toAst(), toPosition())
+
+    if(prefix!=null)
+        return PrefixExpression(prefix.text, expression(0).toAst(), toPosition())
+
+    val funcall = functioncall()?.toAst()
+    if(funcall!=null) return funcall
+
+    if (rangefrom!=null && rangeto!=null) {
+        val defaultstep = if(rto.text == "to") 1 else -1
+        val step = rangestep?.toAst() ?: NumericLiteralValue(DataType.UBYTE, defaultstep, toPosition())
+        return RangeExpr(rangefrom.toAst(), rangeto.toAst(), step, toPosition())
+    }
+
+    if(childCount==3 && children[0].text=="(" && children[2].text==")")
+        return expression(0).toAst()        // expression within ( )
+
+    if(arrayindexed()!=null)
+        return arrayindexed().toAst()
+
+    if(typecast()!=null)
+        return TypecastExpression(expression(0).toAst(), typecast().datatype().toAst(), false, toPosition())
+
+    if(directmemory()!=null)
+        return DirectMemoryRead(directmemory().expression().toAst(), toPosition())
+
+    if(addressof()!=null)
+        return AddressOf(addressof().scoped_identifier().toAst(), toPosition())
+
+    throw FatalAstException(text)
+}
+
+private fun prog8Parser.StringliteralContext.toAst(): StringLiteralValue =
+    StringLiteralValue(unescape(this.STRING().text, toPosition()), ALT_STRING_ENCODING()!=null, toPosition())
+
+private fun prog8Parser.ArrayindexedContext.toAst(): ArrayIndexedExpression {
+    return ArrayIndexedExpression(scoped_identifier().toAst(),
+            arrayindex().toAst(),
+            toPosition())
+}
+
+private fun prog8Parser.Expression_listContext.toAst() = expression().map{ it.toAst() }
+
+private fun prog8Parser.IdentifierContext.toAst() : IdentifierReference =
+        IdentifierReference(listOf(text), toPosition())
+
+private fun prog8Parser.Scoped_identifierContext.toAst() : IdentifierReference =
+        IdentifierReference(NAME().map { it.text }, toPosition())
+
+private fun prog8Parser.FloatliteralContext.toAst() = text.toDouble()
+
+private fun prog8Parser.BooleanliteralContext.toAst() = when(text) {
+    "true" -> true
+    "false" -> false
+    else -> throw FatalAstException(text)
+}
+
+private fun prog8Parser.ArrayliteralContext.toAst() : Array<Expression> =
+        expression().map { it.toAst() }.toTypedArray()
+
+private fun prog8Parser.If_stmtContext.toAst(): IfStatement {
+    val condition = expression().toAst()
+    val trueStatements = statement_block()?.toAst() ?: mutableListOf(statement().toAst())
+    val elseStatements = else_part()?.toAst() ?: mutableListOf()
+    val trueScope = AnonymousScope(trueStatements, statement_block()?.toPosition()
+            ?: statement().toPosition())
+    val elseScope = AnonymousScope(elseStatements, else_part()?.toPosition() ?: toPosition())
+    return IfStatement(condition, trueScope, elseScope, toPosition())
+}
+
+private fun prog8Parser.Else_partContext.toAst(): MutableList<Statement> {
+    return statement_block()?.toAst() ?: mutableListOf(statement().toAst())
+}
+
+private fun prog8Parser.Branch_stmtContext.toAst(): BranchStatement {
+    val branchcondition = branchcondition().toAst()
+    val trueStatements = statement_block()?.toAst() ?: mutableListOf(statement().toAst())
+    val elseStatements = else_part()?.toAst() ?: mutableListOf()
+    val trueScope = AnonymousScope(trueStatements, statement_block()?.toPosition()
+            ?: statement().toPosition())
+    val elseScope = AnonymousScope(elseStatements, else_part()?.toPosition() ?: toPosition())
+    return BranchStatement(branchcondition, trueScope, elseScope, toPosition())
+}
+
+private fun prog8Parser.BranchconditionContext.toAst() = BranchCondition.valueOf(text.substringAfter('_').toUpperCase())
+
+private fun prog8Parser.ForloopContext.toAst(): ForLoop {
+    val loopvar = identifier().toAst()
+    val iterable = expression()!!.toAst()
+    val scope =
+            if(statement()!=null)
+                AnonymousScope(mutableListOf(statement().toAst()), statement().toPosition())
+            else
+                AnonymousScope(statement_block().toAst(), statement_block().toPosition())
+    return ForLoop(loopvar, iterable, scope, toPosition())
+}
+
+private fun prog8Parser.BreakstmtContext.toAst() = Break(toPosition())
+
+private fun prog8Parser.WhileloopContext.toAst(): WhileLoop {
+    val condition = expression().toAst()
+    val statements = statement_block()?.toAst() ?: mutableListOf(statement().toAst())
+    val scope = AnonymousScope(statements, statement_block()?.toPosition()
+            ?: statement().toPosition())
+    return WhileLoop(condition, scope, toPosition())
+}
+
+private fun prog8Parser.RepeatloopContext.toAst(): RepeatLoop {
+    val iterations = expression()?.toAst()
+    val statements = statement_block()?.toAst() ?: mutableListOf(statement().toAst())
+    val scope = AnonymousScope(statements, statement_block()?.toPosition()
+            ?: statement().toPosition())
+    return RepeatLoop(iterations, scope, toPosition())
+}
+
+private fun prog8Parser.UntilloopContext.toAst(): UntilLoop {
+    val untilCondition = expression().toAst()
+    val statements = statement_block()?.toAst() ?: mutableListOf(statement().toAst())
+    val scope = AnonymousScope(statements, statement_block()?.toPosition()
+            ?: statement().toPosition())
+    return UntilLoop(scope, untilCondition, toPosition())
+}
+
+private fun prog8Parser.WhenstmtContext.toAst(): WhenStatement {
+    val condition = expression().toAst()
+    val choices = this.when_choice()?.map { it.toAst() }?.toMutableList() ?: mutableListOf()
+    return WhenStatement(condition, choices, toPosition())
+}
+
+private fun prog8Parser.When_choiceContext.toAst(): WhenChoice {
+    val values = expression_list()?.toAst()
+    val stmt = statement()?.toAst()
+    val stmtBlock = statement_block()?.toAst()?.toMutableList() ?: mutableListOf()
+    if(stmt!=null)
+        stmtBlock.add(stmt)
+    val scope = AnonymousScope(stmtBlock, toPosition())
+    return WhenChoice(values, scope, toPosition())
+}
+
+private fun prog8Parser.VardeclContext.toAst(): VarDecl {
+    return VarDecl(
+            VarDeclType.VAR,
+            datatype()?.toAst() ?: DataType.STRUCT,
+            if(ZEROPAGE() != null) ZeropageWish.PREFER_ZEROPAGE else ZeropageWish.DONTCARE,
+            arrayindex()?.toAst(),
+            varname.text,
+            null,
+            null,
+            ARRAYSIG() != null || arrayindex() != null,
+            false,
+            toPosition()
+    )
+}
+
+internal fun escape(str: String) = str.replace("\t", "\\t").replace("\n", "\\n").replace("\r", "\\r")
+
+internal fun unescape(str: String, position: Position): String {
+    val result = mutableListOf<Char>()
+    val iter = str.iterator()
+    while(iter.hasNext()) {
+        val c = iter.nextChar()
+        if(c=='\\') {
+            val ec = iter.nextChar()
+            result.add(when(ec) {
+                '\\' -> '\\'
+                'n' -> '\n'
+                'r' -> '\r'
+                '"' -> '"'
+                'u' -> {
+                    "${iter.nextChar()}${iter.nextChar()}${iter.nextChar()}${iter.nextChar()}".toInt(16).toChar()
+                }
+                else -> throw SyntaxError("invalid escape char in string: \\$ec", position)
+            })
+        } else {
+            result.add(c)
+        }
+    }
+    return result.joinToString("")
+}

compiler/src/prog8/ast/base/Base.kt

@@ -0,0 +1,172 @@
+package prog8.ast.base
+
+import prog8.ast.Node
+import prog8.compiler.target.CompilationTarget
+
+
+/**************************** AST Data classes ****************************/
+
+enum class DataType {
+    UBYTE,              // pass by value
+    BYTE,               // pass by value
+    UWORD,              // pass by value
+    WORD,               // pass by value
+    FLOAT,              // pass by value
+    STR,                // pass by reference
+    ARRAY_UB,           // pass by reference
+    ARRAY_B,            // pass by reference
+    ARRAY_UW,           // pass by reference
+    ARRAY_W,            // pass by reference
+    ARRAY_F,            // pass by reference
+    STRUCT;             // pass by reference
+
+    /**
+     * is the type assignable to the given other type (perhaps via a typecast) without loss of precision?
+     */
+    infix fun isAssignableTo(targetType: DataType) =
+            when(this) {
+                UBYTE -> targetType in setOf(UBYTE, WORD, UWORD, FLOAT)
+                BYTE -> targetType in setOf(BYTE, WORD, FLOAT)
+                UWORD -> targetType in setOf(UWORD, FLOAT)
+                WORD -> targetType in setOf(WORD, FLOAT)
+                FLOAT -> targetType == FLOAT
+                STR -> targetType == STR
+                in ArrayDatatypes -> targetType == this
+                else -> false
+            }
+
+
+    infix fun isAssignableTo(targetTypes: Set<DataType>) = targetTypes.any { this isAssignableTo it }
+
+    infix fun largerThan(other: DataType) =
+            when(this) {
+                in ByteDatatypes -> false
+                in WordDatatypes -> other in ByteDatatypes
+                else -> true
+            }
+
+    infix fun equalsSize(other: DataType) =
+            when(this) {
+                in ByteDatatypes -> other in ByteDatatypes
+                in WordDatatypes -> other in WordDatatypes
+                else -> false
+            }
+
+    fun memorySize(): Int {
+        return when(this) {
+            in ByteDatatypes -> 1
+            in WordDatatypes -> 2
+            FLOAT -> CompilationTarget.machine.FLOAT_MEM_SIZE
+            in PassByReferenceDatatypes -> CompilationTarget.machine.POINTER_MEM_SIZE
+            else -> -9999999
+        }
+    }
+}
+
+enum class CpuRegister {
+    A,
+    X,
+    Y
+}
+
+enum class RegisterOrPair {
+    A,
+    X,
+    Y,
+    AX,
+    AY,
+    XY;
+
+    companion object {
+        val names by lazy { values().map { it.toString()} }
+    }
+
+}       // only used in parameter and return value specs in asm subroutines
+
+enum class Statusflag {
+    Pc,
+    Pz,
+    Pv,
+    Pn;
+
+    companion object {
+        val names by lazy { values().map { it.toString()} }
+    }
+}
+
+enum class BranchCondition {
+    CS,
+    CC,
+    EQ,
+    Z,
+    NE,
+    NZ,
+    VS,
+    VC,
+    MI,
+    NEG,
+    PL,
+    POS
+}
+
+enum class VarDeclType {
+    VAR,
+    CONST,
+    MEMORY
+}
+
+val ByteDatatypes = setOf(DataType.UBYTE, DataType.BYTE)
+val WordDatatypes = setOf(DataType.UWORD, DataType.WORD)
+val IntegerDatatypes = setOf(DataType.UBYTE, DataType.BYTE, DataType.UWORD, DataType.WORD)
+val NumericDatatypes = setOf(DataType.UBYTE, DataType.BYTE, DataType.UWORD, DataType.WORD, DataType.FLOAT)
+val ArrayDatatypes = setOf(DataType.ARRAY_UB, DataType.ARRAY_B, DataType.ARRAY_UW, DataType.ARRAY_W, DataType.ARRAY_F)
+val IterableDatatypes = setOf(
+        DataType.STR,
+        DataType.ARRAY_UB, DataType.ARRAY_B,
+        DataType.ARRAY_UW, DataType.ARRAY_W,
+        DataType.ARRAY_F)
+val PassByValueDatatypes = NumericDatatypes
+val PassByReferenceDatatypes = IterableDatatypes.plus(DataType.STRUCT)
+val ArrayElementTypes = mapOf(
+        DataType.STR to DataType.UBYTE,
+        DataType.ARRAY_B to DataType.BYTE,
+        DataType.ARRAY_UB to DataType.UBYTE,
+        DataType.ARRAY_W to DataType.WORD,
+        DataType.ARRAY_UW to DataType.UWORD,
+        DataType.ARRAY_F to DataType.FLOAT)
+val ElementArrayTypes = mapOf(
+        DataType.BYTE to DataType.ARRAY_B,
+        DataType.UBYTE to DataType.ARRAY_UB,
+        DataType.WORD to DataType.ARRAY_W,
+        DataType.UWORD to DataType.ARRAY_UW,
+        DataType.FLOAT to DataType.ARRAY_F
+)
+
+// find the parent node of a specific type or interface
+// (useful to figure out in what namespace/block something is defined, etc)
+inline fun <reified T> findParentNode(node: Node): T? {
+    var candidate = node.parent
+    while(candidate !is T && candidate !is ParentSentinel)
+        candidate = candidate.parent
+    return if(candidate is ParentSentinel)
+        null
+    else
+        candidate as T
+}
+
+object ParentSentinel : Node {
+    override val position = Position("<<sentinel>>", 0, 0, 0)
+    override var parent: Node = this
+    override fun linkParents(parent: Node) {}
+    override fun replaceChildNode(node: Node, replacement: Node) {
+        replacement.parent = this
+    }
+}
+
+data class Position(val file: String, val line: Int, val startCol: Int, val endCol: Int) {
+    override fun toString(): String = "[$file: line $line col ${startCol+1}-${endCol+1}]"
+
+    companion object {
+        val DUMMY = Position("<dummy>", 0, 0, 0)
+    }
+}

compiler/src/prog8/ast/base/ErrorReporting.kt

@@ -0,0 +1,44 @@
+package prog8.ast.base
+
+import prog8.parser.ParsingFailedError
+
+
+class ErrorReporter {
+    private enum class MessageSeverity {
+        WARNING,
+        ERROR
+    }
+    private class CompilerMessage(val severity: MessageSeverity, val message: String, val position: Position)
+
+    private val messages = mutableListOf<CompilerMessage>()
+    private val alreadyReportedMessages = mutableSetOf<String>()
+
+    fun err(msg: String, position: Position) = messages.add(CompilerMessage(MessageSeverity.ERROR, msg, position))
+    fun warn(msg: String, position: Position) = messages.add(CompilerMessage(MessageSeverity.WARNING, msg, position))
+
+    fun handle() {
+        var numErrors = 0
+        var numWarnings = 0
+        messages.forEach {
+            when(it.severity) {
+                MessageSeverity.ERROR -> System.err.print("\u001b[91m")  // bright red
+                MessageSeverity.WARNING -> System.err.print("\u001b[93m")  // bright yellow
+            }
+            val msg = "${it.position} ${it.severity} ${it.message}".trim()
+            if(msg !in alreadyReportedMessages) {
+                System.err.println(msg)
+                alreadyReportedMessages.add(msg)
+                when(it.severity) {
+                    MessageSeverity.WARNING -> numWarnings++
+                    MessageSeverity.ERROR -> numErrors++
+                }
+            }
+            System.err.print("\u001b[0m")  // reset color
+        }
+        messages.clear()
+        if(numErrors>0)
+            throw ParsingFailedError("There are $numErrors errors and $numWarnings warnings.")
+    }
+
+    fun isEmpty() = messages.isEmpty()
+}

compiler/src/prog8/ast/base/Errors.kt

@@ -0,0 +1,18 @@
+package prog8.ast.base
+
+import prog8.ast.expressions.IdentifierReference
+
+open class FatalAstException (override var message: String) : Exception(message)
+
+open class AstException (override var message: String) : Exception(message)
+
+open class SyntaxError(override var message: String, val position: Position) : AstException(message) {
+    override fun toString() = "$position Syntax error: $message"
+}
+
+class ExpressionError(message: String, val position: Position) : AstException(message) {
+    override fun toString() = "$position Error: $message"
+}
+
+class UndefinedSymbolError(symbol: IdentifierReference)
+    : SyntaxError("undefined symbol: ${symbol.nameInSource.joinToString(".")}", symbol.position)

compiler/src/prog8/ast/base/Extensions.kt

@@ -0,0 +1,70 @@
+package prog8.ast.base
+
+import prog8.ast.Module
+import prog8.ast.Program
+import prog8.ast.processing.*
+import prog8.compiler.CompilationOptions
+import prog8.compiler.BeforeAsmGenerationAstChanger
+
+
+internal fun Program.checkValid(compilerOptions: CompilationOptions, errors: ErrorReporter) {
+    val checker = AstChecker(this, compilerOptions, errors)
+    checker.visit(this)
+}
+
+internal fun Program.processAstBeforeAsmGeneration(errors: ErrorReporter) {
+    val fixer = BeforeAsmGenerationAstChanger(this, errors)
+    fixer.visit(this)
+    fixer.applyModifications()
+}
+
+internal fun Program.reorderStatements() {
+    val reorder = StatementReorderer(this)
+    reorder.visit(this)
+    reorder.applyModifications()
+}
+
+internal fun Program.addTypecasts(errors: ErrorReporter) {
+    val caster = TypecastsAdder(this, errors)
+    caster.visit(this)
+    caster.applyModifications()
+}
+
+internal fun Program.verifyFunctionArgTypes() {
+    val fixer = VerifyFunctionArgTypes(this)
+    fixer.visit(this)
+}
+
+internal fun Module.checkImportedValid() {
+    val imr = ImportedModuleDirectiveRemover()
+    imr.visit(this, this.parent)
+    imr.applyModifications()
+}
+
+internal fun Program.checkRecursion(errors: ErrorReporter) {
+    val checker = AstRecursionChecker(namespace, errors)
+    checker.visit(this)
+    checker.processMessages(name)
+}
+
+internal fun Program.checkIdentifiers(errors: ErrorReporter) {
+
+    val checker2 = AstIdentifiersChecker(this, errors)
+    checker2.visit(this)
+
+    if(errors.isEmpty()) {
+        val transforms = AstVariousTransforms(this)
+        transforms.visit(this)
+        transforms.applyModifications()
+    }
+
+    if (modules.map { it.name }.toSet().size != modules.size) {
+        throw FatalAstException("modules should all be unique")
+    }
+}
+
+internal fun Program.variousCleanups() {
+    val process = VariousCleanups()
+    process.visit(this)
+    process.applyModifications()
+}

compiler/src/prog8/ast/expressions/AstExpressions.kt

@@ -0,0 +1,853 @@
+package prog8.ast.expressions
+
+import prog8.ast.*
+import prog8.ast.antlr.escape
+import prog8.ast.base.*
+import prog8.ast.processing.AstWalker
+import prog8.ast.processing.IAstVisitor
+import prog8.ast.statements.*
+import prog8.compiler.target.CompilationTarget
+import prog8.functions.BuiltinFunctions
+import prog8.functions.CannotEvaluateException
+import prog8.functions.NotConstArgumentException
+import prog8.functions.builtinFunctionReturnType
+import java.util.*
+import kotlin.math.abs
+
+
+val associativeOperators = setOf("+", "*", "&", "|", "^", "or", "and", "xor", "==", "!=")
+val comparisonOperators = setOf("==", "!=", "<", ">", "<=", ">=")
+
+
+sealed class Expression: Node {
+    abstract fun constValue(program: Program): NumericLiteralValue?
+    abstract fun accept(visitor: IAstVisitor)
+    abstract fun accept(visitor: AstWalker, parent: Node)
+    abstract fun referencesIdentifiers(vararg name: String): Boolean
+    abstract fun inferType(program: Program): InferredTypes.InferredType
+
+    infix fun isSameAs(assigntarget: AssignTarget) = assigntarget.isSameAs(this)
+
+    infix fun isSameAs(other: Expression): Boolean {
+        if(this===other)
+            return true
+        return when(this) {
+            is IdentifierReference ->
+                (other is IdentifierReference && other.nameInSource==nameInSource)
+            is PrefixExpression ->
+                (other is PrefixExpression && other.operator==operator && other.expression isSameAs expression)
+            is BinaryExpression ->
+                (other is BinaryExpression && other.operator==operator
+                        && other.left isSameAs left
+                        && other.right isSameAs right)
+            is ArrayIndexedExpression -> {
+                (other is ArrayIndexedExpression && other.identifier.nameInSource == identifier.nameInSource
+                        && other.arrayspec.index isSameAs arrayspec.index)
+            }
+            is DirectMemoryRead -> {
+                (other is DirectMemoryRead && other.addressExpression isSameAs addressExpression)
+            }
+            is TypecastExpression -> {
+                (other is TypecastExpression && other.implicit==implicit && other.type==type && other.expression isSameAs expression)
+            }
+            is AddressOf -> {
+                (other is AddressOf && other.identifier.nameInSource == identifier.nameInSource)
+            }
+            is RangeExpr -> {
+                (other is RangeExpr && other.from==from && other.to==to && other.step==step)
+            }
+            is FunctionCall -> {
+                (other is FunctionCall && other.target.nameInSource == target.nameInSource
+                        && other.args.size == args.size
+                        && other.args.zip(args).all { it.first isSameAs it.second } )
+            }
+            else -> other==this
+        }
+    }
+}
+
+
+class PrefixExpression(val operator: String, var expression: Expression, override val position: Position) : Expression() {
+    override lateinit var parent: Node
+
+    override fun linkParents(parent: Node) {
+        this.parent = parent
+        expression.linkParents(this)
+    }
+
+    override fun replaceChildNode(node: Node, replacement: Node) {
+        require(node === expression && replacement is Expression)
+        expression = replacement
+        replacement.parent = this
+    }
+
+    override fun constValue(program: Program): NumericLiteralValue? = null
+    override fun accept(visitor: IAstVisitor) = visitor.visit(this)
+    override fun accept(visitor: AstWalker, parent: Node)= visitor.visit(this, parent)
+
+    override fun referencesIdentifiers(vararg name: String) = expression.referencesIdentifiers(*name)
+    override fun inferType(program: Program): InferredTypes.InferredType {
+        val inferred = expression.inferType(program)
+        return when(operator) {
+            "+" -> inferred
+            "~", "not" -> {
+                when(inferred.typeOrElse(DataType.STRUCT)) {
+                    in ByteDatatypes -> InferredTypes.knownFor(DataType.UBYTE)
+                    in WordDatatypes -> InferredTypes.knownFor(DataType.UWORD)
+                    else -> inferred
+                }
+            }
+            "-" -> {
+                when(inferred.typeOrElse(DataType.STRUCT)) {
+                    in ByteDatatypes -> InferredTypes.knownFor(DataType.BYTE)
+                    in WordDatatypes -> InferredTypes.knownFor(DataType.WORD)
+                    else -> inferred
+                }
+            }
+            else -> throw FatalAstException("weird prefix expression operator")
+        }
+    }
+
+    override fun toString(): String {
+        return "Prefix($operator $expression)"
+    }
+}
+
+class BinaryExpression(var left: Expression, var operator: String, var right: Expression, override val position: Position) : Expression() {
+    override lateinit var parent: Node
+
+    override fun linkParents(parent: Node) {
+        this.parent = parent
+        left.linkParents(this)
+        right.linkParents(this)
+    }
+
+    override fun replaceChildNode(node: Node, replacement: Node) {
+        require(replacement is Expression)
+        when {
+            node===left -> left = replacement
+            node===right -> right = replacement
+            else -> throw FatalAstException("invalid replace, no child $node")
+        }
+        replacement.parent = this
+    }
+
+    override fun toString(): String {
+        return "[$left $operator $right]"
+    }
+
+    // binary expression should actually have been optimized away into a single value, before const value was requested...
+    override fun constValue(program: Program): NumericLiteralValue? = null
+
+    override fun accept(visitor: IAstVisitor) = visitor.visit(this)
+    override fun accept(visitor: AstWalker, parent: Node)= visitor.visit(this, parent)
+
+    override fun referencesIdentifiers(vararg name: String) = left.referencesIdentifiers(*name) || right.referencesIdentifiers(*name)
+    override fun inferType(program: Program): InferredTypes.InferredType {
+        val leftDt = left.inferType(program)
+        val rightDt = right.inferType(program)
+        return when (operator) {
+            "+", "-", "*", "**", "%", "/" -> {
+                if (!leftDt.isKnown || !rightDt.isKnown)
+                    InferredTypes.unknown()
+                else {
+                    try {
+                        InferredTypes.knownFor(commonDatatype(
+                                leftDt.typeOrElse(DataType.BYTE),
+                                rightDt.typeOrElse(DataType.BYTE),
+                                null, null).first)
+                    } catch (x: FatalAstException) {
+                        InferredTypes.unknown()
+                    }
+                }
+            }
+            "&" -> leftDt
+            "|" -> leftDt
+            "^" -> leftDt
+            "and", "or", "xor",
+            "<", ">",
+            "<=", ">=",
+            "==", "!=" -> InferredTypes.knownFor(DataType.UBYTE)
+            "<<", ">>" -> leftDt
+            else -> throw FatalAstException("resulting datatype check for invalid operator $operator")
+        }
+    }
+
+    companion object {
+        fun commonDatatype(leftDt: DataType, rightDt: DataType,
+                           left: Expression?, right: Expression?): Pair<DataType, Expression?> {
+            // byte + byte -> byte
+            // byte + word -> word
+            // word + byte -> word
+            // word + word -> word
+            // a combination with a float will be float (but give a warning about this!)
+
+            return when (leftDt) {
+                DataType.UBYTE -> {
+                    when (rightDt) {
+                        DataType.UBYTE -> Pair(DataType.UBYTE, null)
+                        DataType.BYTE -> Pair(DataType.BYTE, left)
+                        DataType.UWORD -> Pair(DataType.UWORD, left)
+                        DataType.WORD -> Pair(DataType.WORD, left)
+                        DataType.FLOAT -> Pair(DataType.FLOAT, left)
+                        else -> Pair(leftDt, null)      // non-numeric datatype
+                    }
+                }
+                DataType.BYTE -> {
+                    when (rightDt) {
+                        DataType.UBYTE -> Pair(DataType.BYTE, right)
+                        DataType.BYTE -> Pair(DataType.BYTE, null)
+                        DataType.UWORD -> Pair(DataType.WORD, left)
+                        DataType.WORD -> Pair(DataType.WORD, left)
+                        DataType.FLOAT -> Pair(DataType.FLOAT, left)
+                        else -> Pair(leftDt, null)      // non-numeric datatype
+                    }
+                }
+                DataType.UWORD -> {
+                    when (rightDt) {
+                        DataType.UBYTE -> Pair(DataType.UWORD, right)
+                        DataType.BYTE -> Pair(DataType.WORD, right)
+                        DataType.UWORD -> Pair(DataType.UWORD, null)
+                        DataType.WORD -> Pair(DataType.WORD, left)
+                        DataType.FLOAT -> Pair(DataType.FLOAT, left)
+                        else -> Pair(leftDt, null)      // non-numeric datatype
+                    }
+                }
+                DataType.WORD -> {
+                    when (rightDt) {
+                        DataType.UBYTE -> Pair(DataType.WORD, right)
+                        DataType.BYTE -> Pair(DataType.WORD, right)
+                        DataType.UWORD -> Pair(DataType.WORD, right)
+                        DataType.WORD -> Pair(DataType.WORD, null)
+                        DataType.FLOAT -> Pair(DataType.FLOAT, left)
+                        else -> Pair(leftDt, null)      // non-numeric datatype
+                    }
+                }
+                DataType.FLOAT -> {
+                    Pair(DataType.FLOAT, right)
+                }
+                else -> Pair(leftDt, null)      // non-numeric datatype
+            }
+        }
+    }
+}
+
+class ArrayIndexedExpression(var identifier: IdentifierReference,
+                             val arrayspec: ArrayIndex,
+                             override val position: Position) : Expression(), IAssignable {
+    override lateinit var parent: Node
+    override fun linkParents(parent: Node) {
+        this.parent = parent
+        identifier.linkParents(this)
+        arrayspec.linkParents(this)
+    }
+
+    override fun replaceChildNode(node: Node, replacement: Node) {
+        when {
+            node===identifier -> identifier = replacement as IdentifierReference
+            node===arrayspec.index -> arrayspec.index = replacement as Expression
+            else -> throw FatalAstException("invalid replace")
+        }
+        replacement.parent = this
+    }
+
+    override fun constValue(program: Program): NumericLiteralValue? = null
+    override fun accept(visitor: IAstVisitor) = visitor.visit(this)
+    override fun accept(visitor: AstWalker, parent: Node)= visitor.visit(this, parent)
+
+    override fun referencesIdentifiers(vararg name: String) = identifier.referencesIdentifiers(*name)
+
+    override fun inferType(program: Program): InferredTypes.InferredType {
+        val target = identifier.targetStatement(program.namespace)
+        if (target is VarDecl) {
+            return when (target.datatype) {
+                DataType.STR -> InferredTypes.knownFor(DataType.UBYTE)
+                in ArrayDatatypes -> InferredTypes.knownFor(ArrayElementTypes.getValue(target.datatype))
+                else -> InferredTypes.unknown()
+            }
+        }
+        return InferredTypes.unknown()
+    }
+
+    override fun toString(): String {
+        return "ArrayIndexed(ident=$identifier, arraysize=$arrayspec; pos=$position)"
+    }
+}
+
+class TypecastExpression(var expression: Expression, var type: DataType, val implicit: Boolean, override val position: Position) : Expression() {
+    override lateinit var parent: Node
+
+    override fun linkParents(parent: Node) {
+        this.parent = parent
+        expression.linkParents(this)
+    }
+
+    override fun replaceChildNode(node: Node, replacement: Node) {
+        require(replacement is Expression && node===expression)
+        expression = replacement
+        replacement.parent = this
+    }
+
+    override fun accept(visitor: IAstVisitor) = visitor.visit(this)
+    override fun accept(visitor: AstWalker, parent: Node)= visitor.visit(this, parent)
+
+    override fun referencesIdentifiers(vararg name: String) = expression.referencesIdentifiers(*name)
+    override fun inferType(program: Program): InferredTypes.InferredType = InferredTypes.knownFor(type)
+    override fun constValue(program: Program): NumericLiteralValue? {
+        val cv = expression.constValue(program) ?: return null
+        val cast = cv.cast(type)
+        return if(cast.isValid)
+            cast.valueOrZero()
+        else
+            null
+    }
+
+    override fun toString(): String {
+        return "Typecast($expression as $type)"
+    }
+}
+
+data class AddressOf(var identifier: IdentifierReference, override val position: Position) : Expression() {
+    override lateinit var parent: Node
+
+    override fun linkParents(parent: Node) {
+        this.parent = parent
+        identifier.parent=this
+    }
+
+    override fun replaceChildNode(node: Node, replacement: Node) {
+        require(replacement is IdentifierReference && node===identifier)
+        identifier = replacement
+        replacement.parent = this
+    }
+
+    override fun constValue(program: Program): NumericLiteralValue? = null
+    override fun referencesIdentifiers(vararg name: String) = false
+    override fun inferType(program: Program): InferredTypes.InferredType = InferredTypes.knownFor(DataType.UWORD)
+    override fun accept(visitor: IAstVisitor) = visitor.visit(this)
+    override fun accept(visitor: AstWalker, parent: Node)= visitor.visit(this, parent)
+}
+
+class DirectMemoryRead(var addressExpression: Expression, override val position: Position) : Expression(), IAssignable {
+    override lateinit var parent: Node
+
+    override fun linkParents(parent: Node) {
+        this.parent = parent
+        this.addressExpression.linkParents(this)
+    }
+
+    override fun replaceChildNode(node: Node, replacement: Node) {
+        require(replacement is Expression && node===addressExpression)
+        addressExpression = replacement
+        replacement.parent = this
+    }
+
+    override fun accept(visitor: IAstVisitor) = visitor.visit(this)
+    override fun accept(visitor: AstWalker, parent: Node)= visitor.visit(this, parent)
+
+    override fun referencesIdentifiers(vararg name: String) = false
+    override fun inferType(program: Program): InferredTypes.InferredType = InferredTypes.knownFor(DataType.UBYTE)
+    override fun constValue(program: Program): NumericLiteralValue? = null
+
+    override fun toString(): String {
+        return "DirectMemoryRead($addressExpression)"
+    }
+}
+
+class NumericLiteralValue(val type: DataType,    // only numerical types allowed
+                          val number: Number,    // can be byte, word or float depending on the type
+                          override val position: Position) : Expression() {
+    override lateinit var parent: Node
+
+    companion object {
+        fun fromBoolean(bool: Boolean, position: Position) =
+                NumericLiteralValue(DataType.UBYTE, if (bool) 1 else 0, position)
+
+        fun optimalNumeric(value: Number, position: Position): NumericLiteralValue {
+            return if(value is Double) {
+                NumericLiteralValue(DataType.FLOAT, value, position)
+            } else {
+                when (val intval = value.toInt()) {
+                    in 0..255 -> NumericLiteralValue(DataType.UBYTE, intval, position)
+                    in -128..127 -> NumericLiteralValue(DataType.BYTE, intval, position)
+                    in 0..65535 -> NumericLiteralValue(DataType.UWORD, intval, position)
+                    in -32768..32767 -> NumericLiteralValue(DataType.WORD, intval, position)
+                    else -> NumericLiteralValue(DataType.FLOAT, intval.toDouble(), position)
+                }
+            }
+        }
+
+        fun optimalInteger(value: Int, position: Position): NumericLiteralValue {
+            return when (value) {
+                in 0..255 -> NumericLiteralValue(DataType.UBYTE, value, position)
+                in -128..127 -> NumericLiteralValue(DataType.BYTE, value, position)
+                in 0..65535 -> NumericLiteralValue(DataType.UWORD, value, position)
+                in -32768..32767 -> NumericLiteralValue(DataType.WORD, value, position)
+                else -> throw FatalAstException("integer overflow: $value")
+            }
+        }
+    }
+
+    val asBooleanValue: Boolean = number.toDouble() != 0.0
+
+    override fun linkParents(parent: Node) {
+        this.parent = parent
+    }
+
+    override fun replaceChildNode(node: Node, replacement: Node) {
+        throw FatalAstException("can't replace here")
+    }
+
+    override fun referencesIdentifiers(vararg name: String) = false
+    override fun constValue(program: Program) = this
+
+    override fun accept(visitor: IAstVisitor) = visitor.visit(this)
+    override fun accept(visitor: AstWalker, parent: Node)= visitor.visit(this, parent)
+
+    override fun toString(): String = "NumericLiteral(${type.name}:$number)"
+
+    override fun inferType(program: Program): InferredTypes.InferredType = InferredTypes.knownFor(type)
+
+    override fun hashCode(): Int = Objects.hash(type, number)
+
+    override fun equals(other: Any?): Boolean {
+        if(other==null || other !is NumericLiteralValue)
+            return false
+        return number.toDouble()==other.number.toDouble()
+    }
+
+    operator fun compareTo(other: NumericLiteralValue): Int = number.toDouble().compareTo(other.number.toDouble())
+
+    class CastValue(val isValid: Boolean, private val value: NumericLiteralValue?) {
+        fun valueOrZero() = if(isValid) value!! else NumericLiteralValue(DataType.UBYTE, 0, Position.DUMMY)
+    }
+
+    fun cast(targettype: DataType): CastValue {
+        if(type==targettype)
+            return CastValue(true, this)
+        val numval = number.toDouble()
+        when(type) {
+            DataType.UBYTE -> {
+                if(targettype== DataType.BYTE && numval <= 127)
+                    return CastValue(true, NumericLiteralValue(targettype, number.toShort(), position))
+                if(targettype== DataType.WORD || targettype== DataType.UWORD)
+                    return CastValue(true, NumericLiteralValue(targettype, number.toInt(), position))
+                if(targettype== DataType.FLOAT)
+                    return CastValue(true, NumericLiteralValue(targettype, number.toDouble(), position))
+            }
+            DataType.BYTE -> {
+                if(targettype== DataType.UBYTE && numval >= 0)
+                    return CastValue(true, NumericLiteralValue(targettype, number.toShort(), position))
+                if(targettype== DataType.UWORD && numval >= 0)
+                    return CastValue(true, NumericLiteralValue(targettype, number.toInt(), position))
+                if(targettype== DataType.WORD)
+                    return CastValue(true, NumericLiteralValue(targettype, number.toInt(), position))
+                if(targettype== DataType.FLOAT)
+                    return CastValue(true, NumericLiteralValue(targettype, number.toDouble(), position))
+            }
+            DataType.UWORD -> {
+                if(targettype== DataType.BYTE && numval <= 127)
+                    return CastValue(true, NumericLiteralValue(targettype, number.toShort(), position))
+                if(targettype== DataType.UBYTE && numval <= 255)
+                    return CastValue(true, NumericLiteralValue(targettype, number.toShort(), position))
+                if(targettype== DataType.WORD && numval <= 32767)
+                    return CastValue(true, NumericLiteralValue(targettype, number.toInt(), position))
+                if(targettype== DataType.FLOAT)
+                    return CastValue(true, NumericLiteralValue(targettype, number.toDouble(), position))
+            }
+            DataType.WORD -> {
+                if(targettype== DataType.BYTE && numval >= -128 && numval <=127)
+                    return CastValue(true, NumericLiteralValue(targettype, number.toShort(), position))
+                if(targettype== DataType.UBYTE && numval >= 0 && numval <= 255)
+                    return CastValue(true, NumericLiteralValue(targettype, number.toShort(), position))
+                if(targettype== DataType.UWORD && numval >=0)
+                    return CastValue(true, NumericLiteralValue(targettype, number.toInt(), position))
+                if(targettype== DataType.FLOAT)
+                    return CastValue(true, NumericLiteralValue(targettype, number.toDouble(), position))
+            }
+            DataType.FLOAT -> {
+                if (targettype == DataType.BYTE && numval >= -128 && numval <=127)
+                    return CastValue(true, NumericLiteralValue(targettype, number.toShort(), position))
+                if (targettype == DataType.UBYTE && numval >=0 && numval <= 255)
+                    return CastValue(true, NumericLiteralValue(targettype, number.toShort(), position))
+                if (targettype == DataType.WORD && numval >= -32768 && numval <= 32767)
+                    return CastValue(true, NumericLiteralValue(targettype, number.toInt(), position))
+                if (targettype == DataType.UWORD && numval >=0 && numval <= 65535)
+                    return CastValue(true, NumericLiteralValue(targettype, number.toInt(), position))
+            }
+            else -> {}
+        }
+        return CastValue(false, null)
+    }
+}
+
+private var heapIdSequence = 0   // unique ids for strings and arrays "on the heap"
+
+class StringLiteralValue(val value: String,
+                         val altEncoding: Boolean,          // such as: screencodes instead of Petscii for the C64
+                         override val position: Position) : Expression() {
+    override lateinit var parent: Node
+
+    val heapId = ++heapIdSequence
+
+    override fun linkParents(parent: Node) {
+        this.parent = parent
+    }
+
+    override fun replaceChildNode(node: Node, replacement: Node) {
+        throw FatalAstException("can't replace here")
+    }
+
+    override fun referencesIdentifiers(vararg name: String) = false
+    override fun constValue(program: Program): NumericLiteralValue? = null
+    override fun accept(visitor: IAstVisitor) = visitor.visit(this)
+    override fun accept(visitor: AstWalker, parent: Node)= visitor.visit(this, parent)
+
+    override fun toString(): String = "'${escape(value)}'"
+    override fun inferType(program: Program): InferredTypes.InferredType = InferredTypes.knownFor(DataType.STR)
+    operator fun compareTo(other: StringLiteralValue): Int = value.compareTo(other.value)
+    override fun hashCode(): Int = Objects.hash(value, altEncoding)
+    override fun equals(other: Any?): Boolean {
+        if(other==null || other !is StringLiteralValue)
+            return false
+        return value==other.value && altEncoding == other.altEncoding
+    }
+}
+
+class ArrayLiteralValue(val type: InferredTypes.InferredType,     // inferred because not all array literals hava a known type yet
+                        val value: Array<Expression>,
+                        override val position: Position) : Expression() {
+    override lateinit var parent: Node
+
+    val heapId = ++heapIdSequence
+
+    override fun linkParents(parent: Node) {
+        this.parent = parent
+        value.forEach {it.linkParents(this)}
+    }
+
+    override fun replaceChildNode(node: Node, replacement: Node) {
+        require(replacement is Expression)
+        val idx = value.indexOfFirst { it===node }
+        value[idx] = replacement
+        replacement.parent = this
+    }
+
+    override fun referencesIdentifiers(vararg name: String) = value.any { it.referencesIdentifiers(*name) }
+    override fun constValue(program: Program): NumericLiteralValue? = null
+    override fun accept(visitor: IAstVisitor) = visitor.visit(this)
+    override fun accept(visitor: AstWalker, parent: Node)= visitor.visit(this, parent)
+
+    override fun toString(): String = "$value"
+    override fun inferType(program: Program): InferredTypes.InferredType = if(type.isKnown) type else guessDatatype(program)
+
+    operator fun compareTo(other: ArrayLiteralValue): Int = throw ExpressionError("cannot order compare arrays", position)
+    override fun hashCode(): Int = Objects.hash(value, type)
+    override fun equals(other: Any?): Boolean {
+        if(other==null || other !is ArrayLiteralValue)
+            return false
+        return type==other.type && value.contentEquals(other.value)
+    }
+
+    fun guessDatatype(program: Program): InferredTypes.InferredType {
+        // Educated guess of the desired array literal's datatype.
+        // If it's inside a for loop, assume the data type of the loop variable is what we want.
+        val forloop = parent as? ForLoop
+        if(forloop != null)  {
+            val loopvarDt = forloop.loopVarDt(program)
+            if(loopvarDt.isKnown) {
+                return if(loopvarDt.typeOrElse(DataType.STRUCT) !in ElementArrayTypes)
+                    InferredTypes.InferredType.unknown()
+                else
+                    InferredTypes.InferredType.known(ElementArrayTypes.getValue(loopvarDt.typeOrElse(DataType.STRUCT)))
+            }
+        }
+
+        // otherwise, select the "biggegst" datatype based on the elements in the array.
+        val datatypesInArray = value.map { it.inferType(program) }
+        require(datatypesInArray.isNotEmpty() && datatypesInArray.all { it.isKnown }) { "can't determine type of empty array" }
+        val dts = datatypesInArray.map { it.typeOrElse(DataType.STRUCT) }
+        return when {
+            DataType.FLOAT in dts -> InferredTypes.InferredType.known(DataType.ARRAY_F)
+            DataType.WORD in dts -> InferredTypes.InferredType.known(DataType.ARRAY_W)
+            DataType.UWORD in dts -> InferredTypes.InferredType.known(DataType.ARRAY_UW)
+            DataType.BYTE in dts -> InferredTypes.InferredType.known(DataType.ARRAY_B)
+            DataType.UBYTE in dts -> InferredTypes.InferredType.known(DataType.ARRAY_UB)
+            else -> InferredTypes.InferredType.unknown()
+        }
+    }
+
+    fun cast(targettype: DataType): ArrayLiteralValue? {
+        if(type.istype(targettype))
+            return this
+        if(targettype in ArrayDatatypes) {
+            val elementType = ArrayElementTypes.getValue(targettype)
+            val castArray = value.map{
+                val num = it as? NumericLiteralValue
+                if(num==null) {
+                    // an array of UWORDs could possibly also contain AddressOfs, other stuff can't be casted
+                    if (elementType != DataType.UWORD || it !is AddressOf)
+                        return null  // can't cast a value of  the array, abort
+                    it
+                } else {
+                    val cast = num.cast(elementType)
+                    if(cast.isValid)
+                        cast.valueOrZero()
+                    else
+                        return null // can't cast a value of the array, abort
+                }
+            }.toTypedArray()
+            return ArrayLiteralValue(InferredTypes.InferredType.known(targettype), castArray, position = position)
+        }
+        return null    // invalid type conversion from $this to $targettype
+    }
+}
+
+class RangeExpr(var from: Expression,
+                var to: Expression,
+                var step: Expression,
+                override val position: Position) : Expression() {
+    override lateinit var parent: Node
+
+    override fun linkParents(parent: Node) {
+        this.parent = parent
+        from.linkParents(this)
+        to.linkParents(this)
+        step.linkParents(this)
+    }
+
+    override fun replaceChildNode(node: Node, replacement: Node) {
+        require(replacement is Expression)
+        when {
+            from===node -> from=replacement
+            to===node -> to=replacement
+            step===node -> step=replacement
+            else -> throw FatalAstException("invalid replacement")
+        }
+        replacement.parent = this
+    }
+
+    override fun constValue(program: Program): NumericLiteralValue? = null
+    override fun accept(visitor: IAstVisitor) = visitor.visit(this)
+    override fun accept(visitor: AstWalker, parent: Node)= visitor.visit(this, parent)
+
+    override fun referencesIdentifiers(vararg name: String): Boolean  = from.referencesIdentifiers(*name) || to.referencesIdentifiers(*name)
+    override fun inferType(program: Program): InferredTypes.InferredType {
+        val fromDt=from.inferType(program)
+        val toDt=to.inferType(program)
+        return when {
+            !fromDt.isKnown || !toDt.isKnown -> InferredTypes.unknown()
+            fromDt istype DataType.UBYTE && toDt istype DataType.UBYTE -> InferredTypes.knownFor(DataType.ARRAY_UB)
+            fromDt istype DataType.UWORD && toDt istype DataType.UWORD -> InferredTypes.knownFor(DataType.ARRAY_UW)
+            fromDt istype DataType.STR && toDt istype DataType.STR -> InferredTypes.knownFor(DataType.STR)
+            fromDt istype DataType.WORD || toDt istype DataType.WORD -> InferredTypes.knownFor(DataType.ARRAY_W)
+            fromDt istype DataType.BYTE || toDt istype DataType.BYTE -> InferredTypes.knownFor(DataType.ARRAY_B)
+            else -> InferredTypes.knownFor(DataType.ARRAY_UB)
+        }
+    }
+    override fun toString(): String {
+        return "RangeExpr(from $from, to $to, step $step, pos=$position)"
+    }
+
+    fun size(): Int? {
+        val fromLv = (from as? NumericLiteralValue)
+        val toLv = (to as? NumericLiteralValue)
+        if(fromLv==null || toLv==null)
+            return null
+        return toConstantIntegerRange()?.count()
+    }
+
+    fun toConstantIntegerRange(): IntProgression? {
+        val fromVal: Int
+        val toVal: Int
+        val fromString = from as? StringLiteralValue
+        val toString = to as? StringLiteralValue
+        if(fromString!=null && toString!=null ) {
+            // string range -> int range over character values
+            fromVal = CompilationTarget.encodeString(fromString.value, fromString.altEncoding)[0].toInt()
+            toVal = CompilationTarget.encodeString(toString.value, fromString.altEncoding)[0].toInt()
+        } else {
+            val fromLv = from as? NumericLiteralValue
+            val toLv = to as? NumericLiteralValue
+            if(fromLv==null || toLv==null)
+                return null         // non-constant range
+            // integer range
+            fromVal = fromLv.number.toInt()
+            toVal = toLv.number.toInt()
+        }
+        val stepVal = (step as? NumericLiteralValue)?.number?.toInt() ?: 1
+        return makeRange(fromVal, toVal, stepVal)
+    }
+}
+
+internal fun makeRange(fromVal: Int, toVal: Int, stepVal: Int): IntProgression {
+    return when {
+        fromVal <= toVal -> when {
+            stepVal <= 0 -> IntRange.EMPTY
+            stepVal == 1 -> fromVal..toVal
+            else -> fromVal..toVal step stepVal
+        }
+        else -> when {
+            stepVal >= 0 -> IntRange.EMPTY
+            stepVal == -1 -> fromVal downTo toVal
+            else -> fromVal downTo toVal step abs(stepVal)
+        }
+    }
+}
+
+data class IdentifierReference(val nameInSource: List<String>, override val position: Position) : Expression(), IAssignable {
+    override lateinit var parent: Node
+
+    fun targetStatement(namespace: INameScope) =
+        if(nameInSource.size==1 && nameInSource[0] in BuiltinFunctions)
+            BuiltinFunctionStatementPlaceholder(nameInSource[0], position)
+        else
+            namespace.lookup(nameInSource, this)
+
+    fun targetVarDecl(namespace: INameScope): VarDecl? = targetStatement(namespace) as? VarDecl
+    fun targetSubroutine(namespace: INameScope): Subroutine? = targetStatement(namespace) as? Subroutine
+
+    override fun equals(other: Any?) = other is IdentifierReference && other.nameInSource==nameInSource
+    override fun hashCode() = nameInSource.hashCode()
+
+    override fun linkParents(parent: Node) {
+        this.parent = parent
+    }
+
+    override fun replaceChildNode(node: Node, replacement: Node) {
+        throw FatalAstException("can't replace here")
+    }
+
+    override fun constValue(program: Program): NumericLiteralValue? {
+        val node = program.namespace.lookup(nameInSource, this)
+                ?: throw UndefinedSymbolError(this)
+        val vardecl = node as? VarDecl
+        if(vardecl==null) {
+            return null
+        } else if(vardecl.type!= VarDeclType.CONST) {
+            return null
+        }
+        return vardecl.value?.constValue(program)
+    }
+
+    override fun toString(): String {
+        return "IdentifierRef($nameInSource)"
+    }
+
+    override fun accept(visitor: IAstVisitor) = visitor.visit(this)
+    override fun accept(visitor: AstWalker, parent: Node)= visitor.visit(this, parent)
+
+    override fun referencesIdentifiers(vararg name: String): Boolean = nameInSource.last() in name
+
+    override fun inferType(program: Program): InferredTypes.InferredType {
+        return when (val targetStmt = targetStatement(program.namespace)) {
+            is VarDecl -> InferredTypes.knownFor(targetStmt.datatype)
+            is StructDecl -> InferredTypes.knownFor(DataType.STRUCT)
+            else -> InferredTypes.InferredType.unknown()
+        }
+    }
+
+    fun memberOfStruct(namespace: INameScope) = this.targetVarDecl(namespace)?.struct
+
+    fun heapId(namespace: INameScope): Int {
+        val node = namespace.lookup(nameInSource, this) ?: throw UndefinedSymbolError(this)
+        val value = (node as? VarDecl)?.value ?: throw FatalAstException("requires a reference value")
+        return when (value) {
+            is IdentifierReference -> value.heapId(namespace)
+            is StringLiteralValue -> value.heapId
+            is ArrayLiteralValue -> value.heapId
+            else -> throw FatalAstException("requires a reference value")
+        }
+    }
+}
+
+class FunctionCall(override var target: IdentifierReference,
+                   override var args: MutableList<Expression>,
+                   override val position: Position) : Expression(), IFunctionCall {
+    override lateinit var parent: Node
+
+    override fun linkParents(parent: Node) {
+        this.parent = parent
+        target.linkParents(this)
+        args.forEach { it.linkParents(this) }
+    }
+
+    override fun replaceChildNode(node: Node, replacement: Node) {
+        if(node===target)
+            target=replacement as IdentifierReference
+        else {
+            val idx = args.indexOfFirst { it===node }
+            args[idx] = replacement as Expression
+        }
+        replacement.parent = this
+    }
+
+    override fun constValue(program: Program) = constValue(program, true)
+
+    private fun constValue(program: Program, withDatatypeCheck: Boolean): NumericLiteralValue? {
+        // if the function is a built-in function and the args are consts, should try to const-evaluate!
+        // lenghts of arrays and strings are constants that are determined at compile time!
+        if(target.nameInSource.size>1) return null
+        try {
+            var resultValue: NumericLiteralValue? = null
+            val func = BuiltinFunctions[target.nameInSource[0]]
+            if(func!=null) {
+                val exprfunc = func.constExpressionFunc
+                if(exprfunc!=null)
+                    resultValue = exprfunc(args, position, program)
+                else if(func.returntype==null)
+                    throw ExpressionError("builtin function ${target.nameInSource[0]} can't be used here because it doesn't return a value", position)
+            }
+
+            if(withDatatypeCheck) {
+                val resultDt = this.inferType(program)
+                if(resultValue==null || resultDt istype resultValue.type)
+                    return resultValue
+                throw FatalAstException("evaluated const expression result value doesn't match expected datatype $resultDt, pos=$position")
+            } else {
+                return resultValue
+            }
+        }
+        catch(x: NotConstArgumentException) {
+            // const-evaluating the builtin function call failed.
+            return null
+        }
+        catch(x: CannotEvaluateException) {
+            // const-evaluating the builtin function call failed.
+            return null
+        }
+    }
+
+    override fun toString(): String {
+        return "FunctionCall(target=$target, pos=$position)"
+    }
+
+    override fun accept(visitor: IAstVisitor) = visitor.visit(this)
+    override fun accept(visitor: AstWalker, parent: Node)= visitor.visit(this, parent)
+
+    override fun referencesIdentifiers(vararg name: String): Boolean = target.referencesIdentifiers(*name) || args.any{it.referencesIdentifiers(*name)}
+
+    override fun inferType(program: Program): InferredTypes.InferredType {
+        val constVal = constValue(program ,false)
+        if(constVal!=null)
+            return InferredTypes.knownFor(constVal.type)
+        val stmt = target.targetStatement(program.namespace) ?: return InferredTypes.unknown()
+        when (stmt) {
+            is BuiltinFunctionStatementPlaceholder -> {
+                if(target.nameInSource[0] == "set_carry" || target.nameInSource[0]=="set_irqd" ||
+                        target.nameInSource[0] == "clear_carry" || target.nameInSource[0]=="clear_irqd") {
+                    return InferredTypes.void() // these have no return value
+                }
+                return builtinFunctionReturnType(target.nameInSource[0], this.args, program)
+            }
+            is Subroutine -> {
+                if(stmt.returntypes.isEmpty())
+                    return InferredTypes.void()     // no return value
+                if(stmt.returntypes.size==1)
+                    return InferredTypes.knownFor(stmt.returntypes[0])
+                return InferredTypes.unknown()     // has multiple return types... so not a single resulting datatype possible
+            }
+            else -> return InferredTypes.unknown()
+        }
+    }
+}

compiler/src/prog8/ast/expressions/InferredTypes.kt

@@ -0,0 +1,60 @@
+package prog8.ast.expressions
+
+import prog8.ast.base.DataType
+import java.util.*
+
+
+object InferredTypes {
+    class InferredType private constructor(val isUnknown: Boolean, val isVoid: Boolean, private var datatype: DataType?) {
+        init {
+            require(!(datatype!=null && (isUnknown || isVoid))) { "invalid combination of args" }
+        }
+
+        val isKnown = datatype!=null
+        fun typeOrElse(alternative: DataType) = if(isUnknown || isVoid) alternative else datatype!!
+        infix fun istype(type: DataType): Boolean = if(isUnknown || isVoid) false else this.datatype==type
+
+        companion object {
+            fun unknown() = InferredType(isUnknown = true, isVoid = false, datatype = null)
+            fun void() = InferredType(isUnknown = false, isVoid = true, datatype = null)
+            fun known(type: DataType) = InferredType(isUnknown = false, isVoid = false, datatype = type)
+        }
+
+        override fun equals(other: Any?): Boolean {
+            if(other !is InferredType)
+                return false
+            return isVoid==other.isVoid && datatype==other.datatype
+        }
+
+        override fun toString(): String {
+            return when {
+                datatype!=null -> datatype.toString()
+                isVoid -> "<void>"
+                else -> "<unknown>"
+            }
+        }
+
+        override fun hashCode(): Int = Objects.hash(isVoid, datatype)
+    }
+
+    private val unknownInstance = InferredType.unknown()
+    private val voidInstance = InferredType.void()
+    private val knownInstances = mapOf(
+            DataType.UBYTE to InferredType.known(DataType.UBYTE),
+            DataType.BYTE to InferredType.known(DataType.BYTE),
+            DataType.UWORD to InferredType.known(DataType.UWORD),
+            DataType.WORD to InferredType.known(DataType.WORD),
+            DataType.FLOAT to InferredType.known(DataType.FLOAT),
+            DataType.STR to InferredType.known(DataType.STR),
+            DataType.ARRAY_UB to InferredType.known(DataType.ARRAY_UB),
+            DataType.ARRAY_B to InferredType.known(DataType.ARRAY_B),
+            DataType.ARRAY_UW to InferredType.known(DataType.ARRAY_UW),
+            DataType.ARRAY_W to InferredType.known(DataType.ARRAY_W),
+            DataType.ARRAY_F to InferredType.known(DataType.ARRAY_F),
+            DataType.STRUCT to InferredType.known(DataType.STRUCT)
+    )
+
+    fun void() = voidInstance
+    fun unknown() = unknownInstance
+    fun knownFor(type: DataType) = knownInstances.getValue(type)
+}

compiler/src/prog8/ast/processing/AstIdentifiersChecker.kt

@@ -0,0 +1,159 @@
+package prog8.ast.processing
+
+import prog8.ast.Module
+import prog8.ast.Program
+import prog8.ast.base.*
+import prog8.ast.expressions.*
+import prog8.ast.statements.*
+import prog8.compiler.target.CompilationTarget
+import prog8.functions.BuiltinFunctions
+
+internal class AstIdentifiersChecker(private val program: Program, private val errors: ErrorReporter) : IAstVisitor {
+    private var blocks = mutableMapOf<String, Block>()
+
+    private fun nameError(name: String, position: Position, existing: Statement) {
+        errors.err("name conflict '$name', also defined in ${existing.position.file} line ${existing.position.line}", position)
+    }
+
+    override fun visit(module: Module) {
+        blocks.clear()  // blocks may be redefined within a different module
+
+        super.visit(module)
+    }
+
+    override fun visit(block: Block) {
+        if(block.name in CompilationTarget.machine.opcodeNames)
+            errors.err("can't use a cpu opcode name as a symbol: '${block.name}'", block.position)
+
+        val existing = blocks[block.name]
+        if(existing!=null)
+            nameError(block.name, block.position, existing)
+        else
+            blocks[block.name] = block
+
+        super.visit(block)
+    }
+
+    override fun visit(decl: VarDecl) {
+        decl.datatypeErrors.forEach { errors.err(it.message, it.position) }
+
+        if(decl.name in BuiltinFunctions)
+            errors.err("builtin function cannot be redefined", decl.position)
+
+        if(decl.name in CompilationTarget.machine.opcodeNames)
+            errors.err("can't use a cpu opcode name as a symbol: '${decl.name}'", decl.position)
+
+        if(decl.datatype==DataType.STRUCT) {
+            if (decl.structHasBeenFlattened)
+                return super.visit(decl)    // don't do this multiple times
+
+            if (decl.struct == null) {
+                errors.err("undefined struct type", decl.position)
+                return super.visit(decl)
+            }
+
+            if (decl.struct!!.statements.any { (it as VarDecl).datatype !in NumericDatatypes })
+                return super.visit(decl)     // a non-numeric member, not supported. proper error is given by AstChecker later
+
+            if (decl.value is NumericLiteralValue) {
+                errors.err("you cannot initialize a struct using a single value", decl.position)
+                return super.visit(decl)
+            }
+
+            if (decl.value != null && decl.value !is ArrayLiteralValue) {
+                errors.err("initializing a struct requires array literal value", decl.value?.position ?: decl.position)
+                return super.visit(decl)
+            }
+        }
+
+        val existing = program.namespace.lookup(listOf(decl.name), decl)
+        if (existing != null && existing !== decl)
+            nameError(decl.name, decl.position, existing)
+
+        super.visit(decl)
+    }
+
+    override fun visit(subroutine: Subroutine) {
+        if(subroutine.name in CompilationTarget.machine.opcodeNames) {
+            errors.err("can't use a cpu opcode name as a symbol: '${subroutine.name}'", subroutine.position)
+        } else if(subroutine.name in BuiltinFunctions) {
+            // the builtin functions can't be redefined
+            errors.err("builtin function cannot be redefined", subroutine.position)
+        } else {
+            // already reported elsewhere:
+            // if (subroutine.parameters.any { it.name in BuiltinFunctions })
+            //    checkResult.add(NameError("builtin function name cannot be used as parameter", subroutine.position))
+
+            val existing = program.namespace.lookup(listOf(subroutine.name), subroutine)
+            if (existing != null && existing !== subroutine)
+                nameError(subroutine.name, subroutine.position, existing)
+
+            // does the parameter redefine a variable declared elsewhere?
+            for(param in subroutine.parameters) {
+                val existingVar = subroutine.lookup(listOf(param.name), subroutine)
+                if (existingVar != null && existingVar.parent !== subroutine) {
+                    nameError(param.name, param.position, existingVar)
+                }
+            }
+
+            // check that there are no local variables, labels, or other subs that redefine the subroutine's parameters
+            val symbolsInSub = subroutine.allDefinedSymbols()
+            val namesInSub = symbolsInSub.map{ it.first }.toSet()
+            val paramNames = subroutine.parameters.map { it.name }.toSet()
+            val paramsToCheck = paramNames.intersect(namesInSub)
+            for(name in paramsToCheck) {
+                val labelOrVar = subroutine.getLabelOrVariable(name)
+                if(labelOrVar!=null && labelOrVar.position != subroutine.position)
+                    nameError(name, labelOrVar.position, subroutine)
+                val sub = subroutine.statements.singleOrNull { it is Subroutine && it.name==name}
+                if(sub!=null)
+                    nameError(name, sub.position, subroutine)
+            }
+
+            if(subroutine.isAsmSubroutine && subroutine.statements.any{it !is InlineAssembly}) {
+                errors.err("asmsub can only contain inline assembly (%asm)", subroutine.position)
+            }
+        }
+
+        super.visit(subroutine)
+    }
+
+    override fun visit(label: Label) {
+        if(label.name in CompilationTarget.machine.opcodeNames)
+            errors.err("can't use a cpu opcode name as a symbol: '${label.name}'", label.position)
+
+        if(label.name in BuiltinFunctions) {
+            // the builtin functions can't be redefined
+            errors.err("builtin function cannot be redefined", label.position)
+        } else {
+            val existing = label.definingSubroutine()?.getAllLabels(label.name) ?: emptyList()
+            for(el in existing) {
+                if(el === label || el.name != label.name)
+                    continue
+                else {
+                    nameError(label.name, label.position, el)
+                    break
+                }
+            }
+        }
+
+        super.visit(label)
+    }
+
+    override fun visit(string: StringLiteralValue) {
+        if (string.value.length !in 1..255)
+            errors.err("string literal length must be between 1 and 255", string.position)
+
+        super.visit(string)
+    }
+
+    override fun visit(structDecl: StructDecl) {
+        for(member in structDecl.statements){
+            val decl = member as? VarDecl
+            if(decl!=null && decl.datatype !in NumericDatatypes)
+                errors.err("structs can only contain numerical types", decl.position)
+        }
+
+        super.visit(structDecl)
+    }
+}

compiler/src/prog8/ast/processing/AstRecursionChecker.kt

@@ -0,0 +1,118 @@
+package prog8.ast.processing
+
+import prog8.ast.INameScope
+import prog8.ast.base.ErrorReporter
+import prog8.ast.base.Position
+import prog8.ast.expressions.FunctionCall
+import prog8.ast.statements.FunctionCallStatement
+import prog8.ast.statements.Subroutine
+
+
+internal class AstRecursionChecker(private val namespace: INameScope,
+                                   private val errors: ErrorReporter) : IAstVisitor {
+    private val callGraph = DirectedGraph<INameScope>()
+
+    fun processMessages(modulename: String) {
+        val cycle = callGraph.checkForCycle()
+        if(cycle.isEmpty())
+            return
+        val chain = cycle.joinToString(" <-- ") { "${it.name} at ${it.position}" }
+        errors.err("Program contains recursive subroutine calls, this is not supported. Recursive chain:\n (a subroutine call in) $chain", Position.DUMMY)
+    }
+
+    override fun visit(functionCallStatement: FunctionCallStatement) {
+        val scope = functionCallStatement.definingScope()
+        val targetStatement = functionCallStatement.target.targetStatement(namespace)
+        if(targetStatement!=null) {
+            val targetScope = when (targetStatement) {
+                is Subroutine -> targetStatement
+                else -> targetStatement.definingScope()
+            }
+            callGraph.add(scope, targetScope)
+        }
+        super.visit(functionCallStatement)
+    }
+
+    override fun visit(functionCall: FunctionCall) {
+        val scope = functionCall.definingScope()
+        val targetStatement = functionCall.target.targetStatement(namespace)
+        if(targetStatement!=null) {
+            val targetScope = when (targetStatement) {
+                is Subroutine -> targetStatement
+                else -> targetStatement.definingScope()
+            }
+            callGraph.add(scope, targetScope)
+        }
+        super.visit(functionCall)
+    }
+
+    private class DirectedGraph<VT> {
+        private val graph = mutableMapOf<VT, MutableSet<VT>>()
+        private var uniqueVertices = mutableSetOf<VT>()
+        val numVertices : Int
+            get() = uniqueVertices.size
+
+        fun add(from: VT, to: VT) {
+            var targets = graph[from]
+            if(targets==null) {
+                targets = mutableSetOf()
+                graph[from] = targets
+            }
+            targets.add(to)
+            uniqueVertices.add(from)
+            uniqueVertices.add(to)
+        }
+
+        fun print() {
+            println("#vertices: $numVertices")
+            graph.forEach { (from, to) ->
+                println("$from   CALLS:")
+                to.forEach { println("   $it") }
+            }
+            val cycle = checkForCycle()
+            if(cycle.isNotEmpty()) {
+                println("CYCLIC!  $cycle")
+            }
+        }
+
+        fun checkForCycle(): MutableList<VT> {
+            val visited = uniqueVertices.associateWith { false }.toMutableMap()
+            val recStack = uniqueVertices.associateWith { false }.toMutableMap()
+            val cycle = mutableListOf<VT>()
+            for(node in uniqueVertices) {
+                if(isCyclicUntil(node, visited, recStack, cycle))
+                    return cycle
+            }
+            return mutableListOf()
+        }
+
+        private fun isCyclicUntil(node: VT,
+                                  visited: MutableMap<VT, Boolean>,
+                                  recStack: MutableMap<VT, Boolean>,
+                                  cycleNodes: MutableList<VT>): Boolean {
+
+            if(recStack[node]==true) return true
+            if(visited[node]==true) return false
+
+            // mark current node as visited and add to recursion stack
+            visited[node] = true
+            recStack[node] = true
+
+            // recurse for all neighbours
+            val neighbors = graph[node]
+            if(neighbors!=null) {
+                for (neighbour in neighbors) {
+                    if (isCyclicUntil(neighbour, visited, recStack, cycleNodes)) {
+                        cycleNodes.add(node)
+                        return true
+                    }
+                }
+            }
+
+            // pop node from recursion stack
+            recStack[node] = false
+            return false
+        }
+    }
+
+}

compiler/src/prog8/ast/processing/AstVariousTransforms.kt

@@ -0,0 +1,161 @@
+package prog8.ast.processing
+
+import prog8.ast.Node
+import prog8.ast.Program
+import prog8.ast.base.*
+import prog8.ast.expressions.*
+import prog8.ast.statements.*
+
+
+internal class AstVariousTransforms(private val program: Program) : AstWalker() {
+    private val noModifications = emptyList<IAstModification>()
+
+    override fun after(functionCallStatement: FunctionCallStatement, parent: Node): Iterable<IAstModification> {
+        if(functionCallStatement.target.nameInSource == listOf("swap")) {
+            // if x and y are both just identifiers, do not rewrite (there should be asm generation for that)
+            // otherwise:
+            // rewrite swap(x,y) as follows:
+            // - declare a temp variable of the same datatype
+            // - temp = x, x = y, y= temp
+            val first = functionCallStatement.args[0]
+            val second = functionCallStatement.args[1]
+            if(first !is IdentifierReference && second !is IdentifierReference) {
+                val dt = first.inferType(program).typeOrElse(DataType.STRUCT)
+                val tempname = "prog8_swaptmp_${functionCallStatement.hashCode()}"
+                val tempvardecl = VarDecl(VarDeclType.VAR, dt, ZeropageWish.DONTCARE, null, tempname, null, null, isArray = false, autogeneratedDontRemove = true, position = first.position)
+                val tempvar = IdentifierReference(listOf(tempname), first.position)
+                val assignTemp = Assignment(
+                        AssignTarget(tempvar, null, null, first.position),
+                        first,
+                        first.position
+                )
+                val assignFirst = Assignment(
+                        AssignTarget.fromExpr(first),
+                        second,
+                        first.position
+                )
+                val assignSecond = Assignment(
+                        AssignTarget.fromExpr(second),
+                        tempvar,
+                        first.position
+                )
+                val scope = AnonymousScope(mutableListOf(tempvardecl, assignTemp, assignFirst, assignSecond), first.position)
+                return listOf(IAstModification.ReplaceNode(functionCallStatement, scope, parent))
+            }
+        }
+
+        return noModifications
+    }
+
+    override fun before(decl: VarDecl, parent: Node): Iterable<IAstModification> {
+        // is it a struct variable? then define all its struct members as mangled names,
+        //    and include the original decl as well.
+        if(decl.datatype==DataType.STRUCT && !decl.structHasBeenFlattened) {
+            val decls = decl.flattenStructMembers()
+            decls.add(decl)
+            val result = AnonymousScope(decls, decl.position)
+            return listOf(IAstModification.ReplaceNode(
+                    decl, result, parent
+            ))
+        }
+
+        return noModifications
+    }
+
+    override fun after(subroutine: Subroutine, parent: Node): Iterable<IAstModification> {
+        // For non-kernel subroutines and non-asm parameters:
+        // inject subroutine params as local variables (if they're not there yet).
+        val symbolsInSub = subroutine.allDefinedSymbols()
+        val namesInSub = symbolsInSub.map{ it.first }.toSet()
+        if(subroutine.asmAddress==null) {
+            if(subroutine.asmParameterRegisters.isEmpty() && subroutine.parameters.isNotEmpty()) {
+                val vars = subroutine.statements.filterIsInstance<VarDecl>().map { it.name }.toSet()
+                if(!vars.containsAll(subroutine.parameters.map{it.name})) {
+                    return subroutine.parameters
+                            .filter { it.name !in namesInSub }
+                            .map {
+                                val vardecl = ParameterVarDecl(it.name, it.type, subroutine.position)
+                                IAstModification.InsertFirst(vardecl, subroutine)
+                            }
+                }
+            }
+        }
+
+        return noModifications
+    }
+
+    override fun before(expr: BinaryExpression, parent: Node): Iterable<IAstModification> {
+        when {
+            expr.left is StringLiteralValue ->
+                return listOf(IAstModification.ReplaceNode(
+                        expr,
+                        processBinaryExprWithString(expr.left as StringLiteralValue, expr.right, expr),
+                        parent
+                ))
+            expr.right is StringLiteralValue ->
+                return listOf(IAstModification.ReplaceNode(
+                        expr,
+                        processBinaryExprWithString(expr.right as StringLiteralValue, expr.left, expr),
+                        parent
+                ))
+        }
+
+        return noModifications
+    }
+
+    override fun after(string: StringLiteralValue, parent: Node): Iterable<IAstModification> {
+        if(string.parent !is VarDecl) {
+            // replace the literal string by a identifier reference to a new local vardecl
+            val vardecl = VarDecl.createAuto(string)
+            val identifier = IdentifierReference(listOf(vardecl.name), vardecl.position)
+            return listOf(
+                    IAstModification.ReplaceNode(string, identifier, parent),
+                    IAstModification.InsertFirst(vardecl, string.definingScope() as Node)
+            )
+        }
+        return noModifications
+    }
+
+    override fun after(array: ArrayLiteralValue, parent: Node): Iterable<IAstModification> {
+        val vardecl = array.parent as? VarDecl
+        if(vardecl!=null) {
+            // adjust the datatype of the array (to an educated guess)
+            val arrayDt = array.type
+            if(!arrayDt.istype(vardecl.datatype)) {
+                val cast = array.cast(vardecl.datatype)
+                if (cast != null && cast!=array)
+                    return listOf(IAstModification.ReplaceNode(vardecl.value!!, cast, vardecl))
+            }
+        } else {
+            val arrayDt = array.guessDatatype(program)
+            if(arrayDt.isKnown) {
+                // this array literal is part of an expression, turn it into an identifier reference
+                val litval2 = array.cast(arrayDt.typeOrElse(DataType.STRUCT))
+                if(litval2!=null && litval2!=array) {
+                    val vardecl2 = VarDecl.createAuto(litval2)
+                    val identifier = IdentifierReference(listOf(vardecl2.name), vardecl2.position)
+                    return listOf(
+                            IAstModification.ReplaceNode(array, identifier, parent),
+                            IAstModification.InsertFirst(vardecl2, array.definingScope() as Node)
+                    )
+                }
+            }
+        }
+        return noModifications
+    }
+
+    private fun processBinaryExprWithString(string: StringLiteralValue, operand: Expression, expr: BinaryExpression): Expression {
+        val constvalue = operand.constValue(program)
+        if(constvalue!=null) {
+            if (expr.operator == "*") {
+                // repeat a string a number of times
+                return StringLiteralValue(string.value.repeat(constvalue.number.toInt()), string.altEncoding, expr.position)
+            }
+        }
+        if(expr.operator == "+" && operand is StringLiteralValue) {
+            // concatenate two strings
+            return StringLiteralValue("${string.value}${operand.value}", string.altEncoding, expr.position)
+        }
+        return expr
+    }
+}

compiler/src/prog8/ast/processing/AstWalker.kt

@@ -0,0 +1,442 @@
+package prog8.ast.processing
+
+import prog8.ast.*
+import prog8.ast.base.FatalAstException
+import prog8.ast.expressions.*
+import prog8.ast.statements.*
+
+
+interface IAstModification {
+    fun perform()
+
+    class Remove(val node: Node, val parent: Node) : IAstModification {
+        override fun perform() {
+            if(parent is INameScope) {
+                if (!parent.statements.remove(node) && parent !is GlobalNamespace)
+                    throw FatalAstException("attempt to remove non-existing node $node")
+            } else {
+                throw FatalAstException("parent of a remove modification is not an INameScope")
+            }
+        }
+    }
+
+    class SetExpression(val setter: (newExpr: Expression) -> Unit, val newExpr: Expression, val parent: Node) : IAstModification {
+        override fun perform() {
+            setter(newExpr)
+            newExpr.linkParents(parent)
+        }
+    }
+
+    class InsertFirst(val stmt: Statement, val parent: Node) : IAstModification {
+        override fun perform() {
+            if(parent is INameScope) {
+                parent.statements.add(0, stmt)
+                stmt.linkParents(parent)
+            } else {
+                throw FatalAstException("parent of an insert modification is not an INameScope")
+            }
+        }
+    }
+
+    class InsertLast(val stmt: Statement, val parent: Node) : IAstModification {
+        override fun perform() {
+            if(parent is INameScope) {
+                parent.statements.add(stmt)
+                stmt.linkParents(parent)
+            } else {
+                throw FatalAstException("parent of an insert modification is not an INameScope")
+            }
+        }
+    }
+
+    class InsertAfter(val after: Statement, val stmt: Statement, val parent: Node) : IAstModification {
+        override fun perform() {
+            if(parent is INameScope) {
+                val idx = parent.statements.indexOfFirst { it===after } + 1
+                parent.statements.add(idx, stmt)
+                stmt.linkParents(parent)
+            } else {
+                throw FatalAstException("parent of an insert modification is not an INameScope")
+            }
+        }
+    }
+
+    class InsertBefore(val before: Statement, val stmt: Statement, val parent: Node) : IAstModification {
+        override fun perform() {
+            if(parent is INameScope) {
+                val idx = parent.statements.indexOfFirst { it===before }
+                parent.statements.add(idx, stmt)
+                stmt.linkParents(parent)
+            } else {
+                throw FatalAstException("parent of an insert modification is not an INameScope")
+            }
+        }
+    }
+
+    class ReplaceNode(val node: Node, val replacement: Node, val parent: Node) : IAstModification {
+        override fun perform() {
+            parent.replaceChildNode(node, replacement)
+            replacement.linkParents(parent)
+        }
+    }
+
+    class SwapOperands(val expr: BinaryExpression): IAstModification {
+        override fun perform() {
+            val tmp = expr.left
+            expr.left = expr.right
+            expr.right = tmp
+        }
+    }
+}
+
+
+abstract class AstWalker {
+    open fun before(addressOf: AddressOf, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(array: ArrayLiteralValue, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(arrayIndexedExpression: ArrayIndexedExpression, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(assignTarget: AssignTarget, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(assignment: Assignment, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(block: Block, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(branchStatement: BranchStatement, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(breakStmt: Break, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(builtinFunctionStatementPlaceholder: BuiltinFunctionStatementPlaceholder, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(decl: VarDecl, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(directive: Directive, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(expr: BinaryExpression, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(expr: PrefixExpression, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(forLoop: ForLoop, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(repeatLoop: RepeatLoop, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(functionCall: FunctionCall, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(functionCallStatement: FunctionCallStatement, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(identifier: IdentifierReference, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(ifStatement: IfStatement, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(inlineAssembly: InlineAssembly, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(jump: Jump, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(label: Label, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(memread: DirectMemoryRead, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(memwrite: DirectMemoryWrite, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(module: Module, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(nopStatement: NopStatement, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(numLiteral: NumericLiteralValue, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(postIncrDecr: PostIncrDecr, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(program: Program, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(range: RangeExpr, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(untilLoop: UntilLoop, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(returnStmt: Return, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(scope: AnonymousScope, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(string: StringLiteralValue, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(structDecl: StructDecl, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(subroutine: Subroutine, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(typecast: TypecastExpression, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(whenChoice: WhenChoice, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(whenStatement: WhenStatement, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(whileLoop: WhileLoop, parent: Node): Iterable<IAstModification> = emptyList()
+
+    open fun after(addressOf: AddressOf, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun after(array: ArrayLiteralValue, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun after(arrayIndexedExpression: ArrayIndexedExpression, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun after(assignTarget: AssignTarget, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun after(assignment: Assignment, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun after(block: Block, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun after(branchStatement: BranchStatement, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun after(breakStmt: Break, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun after(builtinFunctionStatementPlaceholder: BuiltinFunctionStatementPlaceholder, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun after(decl: VarDecl, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun after(directive: Directive, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun after(expr: BinaryExpression, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun after(expr: PrefixExpression, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun after(forLoop: ForLoop, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun after(repeatLoop: RepeatLoop, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun after(functionCall: FunctionCall, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun after(functionCallStatement: FunctionCallStatement, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun after(identifier: IdentifierReference, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun after(ifStatement: IfStatement, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun after(inlineAssembly: InlineAssembly, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun after(jump: Jump, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun after(label: Label, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun after(memread: DirectMemoryRead, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun after(memwrite: DirectMemoryWrite, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun after(module: Module, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun after(nopStatement: NopStatement, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun after(numLiteral: NumericLiteralValue, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun after(postIncrDecr: PostIncrDecr, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun after(program: Program, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun after(range: RangeExpr, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun after(untilLoop: UntilLoop, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun after(returnStmt: Return, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun after(scope: AnonymousScope, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun after(string: StringLiteralValue, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun after(structDecl: StructDecl, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun after(subroutine: Subroutine, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun after(typecast: TypecastExpression, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun after(whenChoice: WhenChoice, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun after(whenStatement: WhenStatement, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun after(whileLoop: WhileLoop, parent: Node): Iterable<IAstModification> = emptyList()
+
+    private val modifications = mutableListOf<Triple<IAstModification, Node, Node>>()
+
+    private fun track(mods: Iterable<IAstModification>, node: Node, parent: Node) {
+        for (it in mods) modifications += Triple(it, node, parent)
+    }
+
+    fun applyModifications(): Int {
+        modifications.forEach {
+            it.first.perform()
+        }
+        val amount = modifications.size
+        modifications.clear()
+        return amount
+    }
+
+    fun visit(program: Program) {
+        track(before(program, program), program, program)
+        program.modules.forEach { it.accept(this, program) }
+        track(after(program, program), program, program)
+    }
+
+    fun visit(module: Module, parent: Node) {
+        track(before(module, parent), module, parent)
+        module.statements.forEach{ it.accept(this, module) }
+        track(after(module, parent), module, parent)
+    }
+
+    fun visit(expr: PrefixExpression, parent: Node) {
+        track(before(expr, parent), expr, parent)
+        expr.expression.accept(this, expr)
+        track(after(expr, parent), expr, parent)
+    }
+
+    fun visit(expr: BinaryExpression, parent: Node) {
+        track(before(expr, parent), expr, parent)
+        expr.left.accept(this, expr)
+        expr.right.accept(this, expr)
+        track(after(expr, parent), expr, parent)
+    }
+
+    fun visit(directive: Directive, parent: Node) {
+        track(before(directive, parent), directive, parent)
+        track(after(directive, parent), directive, parent)
+    }
+
+    fun visit(block: Block, parent: Node) {
+        track(before(block, parent), block, parent)
+        block.statements.forEach { it.accept(this, block) }
+        track(after(block, parent), block, parent)
+    }
+
+    fun visit(decl: VarDecl, parent: Node) {
+        track(before(decl, parent), decl, parent)
+        decl.value?.accept(this, decl)
+        decl.arraysize?.accept(this, decl)
+        track(after(decl, parent), decl, parent)
+    }
+
+    fun visit(subroutine: Subroutine, parent: Node) {
+        track(before(subroutine, parent), subroutine, parent)
+        subroutine.statements.forEach { it.accept(this, subroutine) }
+        track(after(subroutine, parent), subroutine, parent)
+    }
+
+    fun visit(functionCall: FunctionCall, parent: Node) {
+        track(before(functionCall, parent), functionCall, parent)
+        functionCall.target.accept(this, functionCall)
+        functionCall.args.forEach { it.accept(this, functionCall) }
+        track(after(functionCall, parent), functionCall, parent)
+    }
+
+    fun visit(functionCallStatement: FunctionCallStatement, parent: Node) {
+        track(before(functionCallStatement, parent), functionCallStatement, parent)
+        functionCallStatement.target.accept(this, functionCallStatement)
+        functionCallStatement.args.forEach { it.accept(this, functionCallStatement) }
+        track(after(functionCallStatement, parent), functionCallStatement, parent)
+    }
+
+    fun visit(identifier: IdentifierReference, parent: Node) {
+        track(before(identifier, parent), identifier, parent)
+        track(after(identifier, parent), identifier, parent)
+    }
+
+    fun visit(jump: Jump, parent: Node) {
+        track(before(jump, parent), jump, parent)
+        jump.identifier?.accept(this, jump)
+        track(after(jump, parent), jump, parent)
+    }
+
+    fun visit(ifStatement: IfStatement, parent: Node) {
+        track(before(ifStatement, parent), ifStatement, parent)
+        ifStatement.condition.accept(this, ifStatement)
+        ifStatement.truepart.accept(this, ifStatement)
+        ifStatement.elsepart.accept(this, ifStatement)
+        track(after(ifStatement, parent), ifStatement, parent)
+    }
+
+    fun visit(branchStatement: BranchStatement, parent: Node) {
+        track(before(branchStatement, parent), branchStatement, parent)
+        branchStatement.truepart.accept(this, branchStatement)
+        branchStatement.elsepart.accept(this, branchStatement)
+        track(after(branchStatement, parent), branchStatement, parent)
+    }
+
+    fun visit(range: RangeExpr, parent: Node) {
+        track(before(range, parent), range, parent)
+        range.from.accept(this, range)
+        range.to.accept(this, range)
+        range.step.accept(this, range)
+        track(after(range, parent), range, parent)
+    }
+
+    fun visit(label: Label, parent: Node) {
+        track(before(label, parent), label, parent)
+        track(after(label, parent), label, parent)
+    }
+
+    fun visit(numLiteral: NumericLiteralValue, parent: Node) {
+        track(before(numLiteral, parent), numLiteral, parent)
+        track(after(numLiteral, parent), numLiteral, parent)
+    }
+
+    fun visit(string: StringLiteralValue, parent: Node) {
+        track(before(string, parent), string, parent)
+        track(after(string, parent), string, parent)
+    }
+
+    fun visit(array: ArrayLiteralValue, parent: Node) {
+        track(before(array, parent), array, parent)
+        array.value.forEach { v->v.accept(this, array) }
+        track(after(array, parent), array, parent)
+    }
+
+    fun visit(assignment: Assignment, parent: Node) {
+        track(before(assignment, parent), assignment, parent)
+        assignment.target.accept(this, assignment)
+        assignment.value.accept(this, assignment)
+        track(after(assignment, parent), assignment, parent)
+    }
+
+    fun visit(postIncrDecr: PostIncrDecr, parent: Node) {
+        track(before(postIncrDecr, parent), postIncrDecr, parent)
+        postIncrDecr.target.accept(this, postIncrDecr)
+        track(after(postIncrDecr, parent), postIncrDecr, parent)
+    }
+
+    fun visit(breakStmt: Break, parent: Node) {
+        track(before(breakStmt, parent), breakStmt, parent)
+        track(after(breakStmt, parent), breakStmt, parent)
+    }
+
+    fun visit(forLoop: ForLoop, parent: Node) {
+        track(before(forLoop, parent), forLoop, parent)
+        forLoop.loopVar.accept(this, forLoop)
+        forLoop.iterable.accept(this, forLoop)
+        forLoop.body.accept(this, forLoop)
+        track(after(forLoop, parent), forLoop, parent)
+    }
+
+    fun visit(whileLoop: WhileLoop, parent: Node) {
+        track(before(whileLoop, parent), whileLoop, parent)
+        whileLoop.condition.accept(this, whileLoop)
+        whileLoop.body.accept(this, whileLoop)
+        track(after(whileLoop, parent), whileLoop, parent)
+    }
+
+    fun visit(repeatLoop: RepeatLoop, parent: Node) {
+        track(before(repeatLoop, parent), repeatLoop, parent)
+        repeatLoop.iterations?.accept(this, repeatLoop)
+        repeatLoop.body.accept(this, repeatLoop)
+        track(after(repeatLoop, parent), repeatLoop, parent)
+    }
+
+    fun visit(untilLoop: UntilLoop, parent: Node) {
+        track(before(untilLoop, parent), untilLoop, parent)
+        untilLoop.untilCondition.accept(this, untilLoop)
+        untilLoop.body.accept(this, untilLoop)
+        track(after(untilLoop, parent), untilLoop, parent)
+    }
+
+    fun visit(returnStmt: Return, parent: Node) {
+        track(before(returnStmt, parent), returnStmt, parent)
+        returnStmt.value?.accept(this, returnStmt)
+        track(after(returnStmt, parent), returnStmt, parent)
+    }
+
+    fun visit(arrayIndexedExpression: ArrayIndexedExpression, parent: Node) {
+        track(before(arrayIndexedExpression, parent), arrayIndexedExpression, parent)
+        arrayIndexedExpression.identifier.accept(this, arrayIndexedExpression)
+        arrayIndexedExpression.arrayspec.accept(this, arrayIndexedExpression)
+        track(after(arrayIndexedExpression, parent), arrayIndexedExpression, parent)
+    }
+
+    fun visit(assignTarget: AssignTarget, parent: Node) {
+        track(before(assignTarget, parent), assignTarget, parent)
+        assignTarget.arrayindexed?.accept(this, assignTarget)
+        assignTarget.identifier?.accept(this, assignTarget)
+        assignTarget.memoryAddress?.accept(this, assignTarget)
+        track(after(assignTarget, parent), assignTarget, parent)
+    }
+
+    fun visit(scope: AnonymousScope, parent: Node) {
+        track(before(scope, parent), scope, parent)
+        scope.statements.forEach { it.accept(this, scope) }
+        track(after(scope, parent), scope, parent)
+    }
+
+    fun visit(typecast: TypecastExpression, parent: Node) {
+        track(before(typecast, parent), typecast, parent)
+        typecast.expression.accept(this, typecast)
+        track(after(typecast, parent), typecast, parent)
+    }
+
+    fun visit(memread: DirectMemoryRead, parent: Node) {
+        track(before(memread, parent), memread, parent)
+        memread.addressExpression.accept(this, memread)
+        track(after(memread, parent), memread, parent)
+    }
+
+    fun visit(memwrite: DirectMemoryWrite, parent: Node) {
+        track(before(memwrite, parent), memwrite, parent)
+        memwrite.addressExpression.accept(this, memwrite)
+        track(after(memwrite, parent), memwrite, parent)
+    }
+
+    fun visit(addressOf: AddressOf, parent: Node) {
+        track(before(addressOf, parent), addressOf, parent)
+        addressOf.identifier.accept(this, addressOf)
+        track(after(addressOf, parent), addressOf, parent)
+    }
+
+    fun visit(inlineAssembly: InlineAssembly, parent: Node) {
+        track(before(inlineAssembly, parent), inlineAssembly, parent)
+        track(after(inlineAssembly, parent), inlineAssembly, parent)
+    }
+
+    fun visit(builtinFunctionStatementPlaceholder: BuiltinFunctionStatementPlaceholder, parent: Node) {
+        track(before(builtinFunctionStatementPlaceholder, parent), builtinFunctionStatementPlaceholder, parent)
+        track(after(builtinFunctionStatementPlaceholder, parent), builtinFunctionStatementPlaceholder, parent)
+    }
+
+    fun visit(nopStatement: NopStatement, parent: Node) {
+        track(before(nopStatement, parent), nopStatement, parent)
+        track(after(nopStatement, parent), nopStatement, parent)
+    }
+
+    fun visit(whenStatement: WhenStatement, parent: Node) {
+        track(before(whenStatement, parent), whenStatement, parent)
+        whenStatement.condition.accept(this, whenStatement)
+        whenStatement.choices.forEach { it.accept(this, whenStatement) }
+        track(after(whenStatement, parent), whenStatement, parent)
+    }
+
+    fun visit(whenChoice: WhenChoice, parent: Node) {
+        track(before(whenChoice, parent), whenChoice, parent)
+        whenChoice.values?.forEach { it.accept(this, whenChoice) }
+        whenChoice.statements.accept(this, whenChoice)
+        track(after(whenChoice, parent), whenChoice, parent)
+    }
+
+    fun visit(structDecl: StructDecl, parent: Node) {
+        track(before(structDecl, parent), structDecl, parent)
+        structDecl.statements.forEach { it.accept(this, structDecl) }
+        track(after(structDecl, parent), structDecl, parent)
+    }
+}
+

compiler/src/prog8/ast/processing/IAstVisitor.kt

@@ -0,0 +1,179 @@
+package prog8.ast.processing
+
+import prog8.ast.Module
+import prog8.ast.Program
+import prog8.ast.expressions.*
+import prog8.ast.statements.*
+
+interface IAstVisitor {
+    fun visit(program: Program) {
+        program.modules.forEach { it.accept(this) }
+    }
+
+    fun visit(module: Module) {
+        module.statements.forEach{ it.accept(this) }
+    }
+
+    fun visit(expr: PrefixExpression) {
+        expr.expression.accept(this)
+    }
+
+    fun visit(expr: BinaryExpression) {
+        expr.left.accept(this)
+        expr.right.accept(this)
+    }
+
+    fun visit(directive: Directive) {
+    }
+
+    fun visit(block: Block) {
+        block.statements.forEach { it.accept(this) }
+    }
+
+    fun visit(decl: VarDecl) {
+        decl.value?.accept(this)
+        decl.arraysize?.accept(this)
+    }
+
+    fun visit(subroutine: Subroutine) {
+        subroutine.statements.forEach { it.accept(this) }
+    }
+
+    fun visit(functionCall: FunctionCall) {
+        functionCall.target.accept(this)
+        functionCall.args.forEach { it.accept(this) }
+    }
+
+    fun visit(functionCallStatement: FunctionCallStatement) {
+        functionCallStatement.target.accept(this)
+        functionCallStatement.args.forEach { it.accept(this) }
+    }
+
+    fun visit(identifier: IdentifierReference) {
+    }
+
+    fun visit(jump: Jump) {
+        jump.identifier?.accept(this)
+    }
+
+    fun visit(ifStatement: IfStatement) {
+        ifStatement.condition.accept(this)
+        ifStatement.truepart.accept(this)
+        ifStatement.elsepart.accept(this)
+    }
+
+    fun visit(branchStatement: BranchStatement) {
+        branchStatement.truepart.accept(this)
+        branchStatement.elsepart.accept(this)
+    }
+
+    fun visit(range: RangeExpr) {
+        range.from.accept(this)
+        range.to.accept(this)
+        range.step.accept(this)
+    }
+
+    fun visit(label: Label) {
+    }
+
+    fun visit(numLiteral: NumericLiteralValue) {
+    }
+
+    fun visit(string: StringLiteralValue) {
+    }
+
+    fun visit(array: ArrayLiteralValue) {
+        array.value.forEach { v->v.accept(this) }
+    }
+
+    fun visit(assignment: Assignment) {
+        assignment.target.accept(this)
+        assignment.value.accept(this)
+    }
+
+    fun visit(postIncrDecr: PostIncrDecr) {
+        postIncrDecr.target.accept(this)
+    }
+
+    fun visit(breakStmt: Break) {
+    }
+
+    fun visit(forLoop: ForLoop) {
+        forLoop.loopVar.accept(this)
+        forLoop.iterable.accept(this)
+        forLoop.body.accept(this)
+    }
+
+    fun visit(whileLoop: WhileLoop) {
+        whileLoop.condition.accept(this)
+        whileLoop.body.accept(this)
+    }
+
+    fun visit(repeatLoop: RepeatLoop) {
+        repeatLoop.iterations?.accept(this)
+        repeatLoop.body.accept(this)
+    }
+
+    fun visit(untilLoop: UntilLoop) {
+        untilLoop.untilCondition.accept(this)
+        untilLoop.body.accept(this)
+    }
+
+    fun visit(returnStmt: Return) {
+        returnStmt.value?.accept(this)
+    }
+
+    fun visit(arrayIndexedExpression: ArrayIndexedExpression) {
+        arrayIndexedExpression.identifier.accept(this)
+        arrayIndexedExpression.arrayspec.accept(this)
+    }
+
+    fun visit(assignTarget: AssignTarget) {
+        assignTarget.arrayindexed?.accept(this)
+        assignTarget.identifier?.accept(this)
+        assignTarget.memoryAddress?.accept(this)
+    }
+
+    fun visit(scope: AnonymousScope) {
+        scope.statements.forEach { it.accept(this) }
+    }
+
+    fun visit(typecast: TypecastExpression) {
+        typecast.expression.accept(this)
+    }
+
+    fun visit(memread: DirectMemoryRead) {
+        memread.addressExpression.accept(this)
+    }
+
+    fun visit(memwrite: DirectMemoryWrite) {
+        memwrite.addressExpression.accept(this)
+    }
+
+    fun visit(addressOf: AddressOf) {
+        addressOf.identifier.accept(this)
+    }
+
+    fun visit(inlineAssembly: InlineAssembly) {
+    }
+
+    fun visit(builtinFunctionStatementPlaceholder: BuiltinFunctionStatementPlaceholder) {
+    }
+
+    fun visit(nopStatement: NopStatement) {
+    }
+
+    fun visit(whenStatement: WhenStatement) {
+        whenStatement.condition.accept(this)
+        whenStatement.choices.forEach { it.accept(this) }
+    }
+
+    fun visit(whenChoice: WhenChoice) {
+        whenChoice.values?.forEach { it.accept(this) }
+        whenChoice.statements.accept(this)
+    }
+
+    fun visit(structDecl: StructDecl) {
+        structDecl.statements.forEach { it.accept(this) }
+    }
+}

compiler/src/prog8/ast/processing/ImportedModuleDirectiveRemover.kt

@@ -0,0 +1,21 @@
+package prog8.ast.processing
+
+import prog8.ast.Node
+import prog8.ast.statements.Directive
+
+
+internal class ImportedModuleDirectiveRemover: AstWalker() {
+    /**
+     * Most global directives don't apply for imported modules, so remove them
+     */
+
+    private val moduleLevelDirectives = listOf("%output", "%launcher", "%zeropage", "%zpreserved", "%address")
+    private val noModifications = emptyList<IAstModification>()
+
+    override fun before(directive: Directive, parent: Node): Iterable<IAstModification> {
+        if(directive.directive in moduleLevelDirectives) {
+            return listOf(IAstModification.Remove(directive, parent))
+        }
+        return noModifications
+    }
+}

compiler/src/prog8/ast/processing/ReflectionAstWalker.kt

@@ -0,0 +1,71 @@
+package prog8.ast.processing
+
+
+/*
+This is here for reference only, reflection based ast walking is very slow
+when compared to the more verbose visitor pattern interfaces.
+Too bad, because the code is very small
+*/
+
+
+//import prog8.ast.NoAstWalk
+//import prog8.ast.Node
+//import prog8.ast.Program
+//import prog8.ast.base.Position
+//import prog8.ast.expressions.BinaryExpression
+//import prog8.ast.expressions.NumericLiteralValue
+//import kotlin.reflect.KClass
+//import kotlin.reflect.KVisibility
+//import kotlin.reflect.full.declaredMemberProperties
+//import kotlin.reflect.full.isSubtypeOf
+//import kotlin.reflect.full.starProjectedType
+//
+//
+//class ReflectionAstWalker {
+//    private val nodeType = Node::class.starProjectedType
+//    private val collectionType = Collection::class.starProjectedType
+//
+//
+//    fun walk(node: Node, nesting: Int) {
+//        val nodetype: KClass<out Node> = node::class
+//        val indent = "  ".repeat(nesting)
+//        //println("$indent VISITING ${nodetype.simpleName}")
+//        val visibleAstMembers = nodetype.declaredMemberProperties.filter {
+//            it.visibility!=KVisibility.PRIVATE && !it.isLateinit &&
+//                    !(it.annotations.any{a->a is NoAstWalk})
+//        }
+//        for(prop in visibleAstMembers) {
+//            if(prop.returnType.isSubtypeOf(nodeType)) {
+//                // println("$indent +PROP: ${prop.name}")
+//                walk(prop.call(node) as Node, nesting + 1)
+//            }
+//            else if(prop.returnType.isSubtypeOf(collectionType)) {
+//                val elementType = prop.returnType.arguments.single().type
+//                if(elementType!=null && elementType.isSubtypeOf(nodeType)) {
+//                    val nodes = prop.call(node) as Collection<Node>
+//                    nodes.forEach { walk(it, nesting+1) }
+//                }
+//            }
+//        }
+//    }
+//    fun walk(program: Program) {
+//        for(module in program.modules) {
+//            println("---MODULE $module---")
+//            walk(module, 0)
+//        }
+//    }
+//}
+//
+//
+//fun main() {
+//    val ast = BinaryExpression(
+//            NumericLiteralValue.optimalInteger(100, Position.DUMMY),
+//            "+",
+//            NumericLiteralValue.optimalInteger(200, Position.DUMMY),
+//            Position.DUMMY
+//    )
+//
+//    val walker = ReflectionAstWalker()
+//    walker.walk(ast,0)
+//
+//}

compiler/src/prog8/ast/processing/StatementReorderer.kt

@@ -0,0 +1,228 @@
+package prog8.ast.processing
+
+import prog8.ast.*
+import prog8.ast.base.*
+import prog8.ast.expressions.*
+import prog8.ast.statements.*
+
+
+internal class StatementReorderer(val program: Program) : AstWalker() {
+    // Reorders the statements in a way the compiler needs.
+    // - 'main' block must be the very first statement UNLESS it has an address set.
+    // - library blocks are put last.
+    // - blocks are ordered by address, where blocks without address are placed last.
+    // - in every scope, most directives and vardecls are moved to the top.
+    // - the 'start' subroutine is moved to the top.
+    // - (syntax desugaring) a vardecl with a non-const initializer value is split into a regular vardecl and an assignment statement.
+    // - (syntax desugaring) struct value assignment is expanded into several struct member assignments.
+    // - in-place assignments are reordered a bit so that they are mostly of the form A = A <operator> <rest>
+    // - sorts the choices in when statement.
+    // - insert AddressOf (&) expression where required (string params to a UWORD function param etc).
+
+    private val noModifications = emptyList<IAstModification>()
+    private val directivesToMove = setOf("%output", "%launcher", "%zeropage", "%zpreserved", "%address", "%option")
+
+    override fun after(module: Module, parent: Node): Iterable<IAstModification> {
+        val (blocks, other) = module.statements.partition { it is Block }
+        module.statements = other.asSequence().plus(blocks.sortedBy { (it as Block).address ?: Int.MAX_VALUE }).toMutableList()
+
+        val mainBlock = module.statements.filterIsInstance<Block>().firstOrNull { it.name=="main" }
+        if(mainBlock!=null && mainBlock.address==null) {
+            module.statements.remove(mainBlock)
+            module.statements.add(0, mainBlock)
+        }
+
+        reorderVardeclsAndDirectives(module.statements)
+        return noModifications
+    }
+
+    private fun reorderVardeclsAndDirectives(statements: MutableList<Statement>) {
+        val varDecls = statements.filterIsInstance<VarDecl>()
+        statements.removeAll(varDecls)
+        statements.addAll(0, varDecls)
+
+        val directives = statements.filterIsInstance<Directive>().filter {it.directive in directivesToMove}
+        statements.removeAll(directives)
+        statements.addAll(0, directives)
+    }
+
+    override fun before(block: Block, parent: Node): Iterable<IAstModification> {
+        parent as Module
+        if(block.isInLibrary) {
+            return listOf(
+                    IAstModification.Remove(block, parent),
+                    IAstModification.InsertLast(block, parent)
+            )
+        }
+
+        reorderVardeclsAndDirectives(block.statements)
+        return noModifications
+    }
+
+    override fun before(subroutine: Subroutine, parent: Node): Iterable<IAstModification> {
+        if(subroutine.name=="start" && parent is Block) {
+            if(parent.statements.filterIsInstance<Subroutine>().first().name!="start") {
+                return listOf(
+                        IAstModification.Remove(subroutine, parent),
+                        IAstModification.InsertFirst(subroutine, parent)
+                )
+            }
+        }
+        return noModifications
+    }
+
+    override fun after(decl: VarDecl, parent: Node): Iterable<IAstModification> {
+        val declValue = decl.value
+        if(declValue!=null && decl.type== VarDeclType.VAR && decl.datatype in NumericDatatypes) {
+            val declConstValue = declValue.constValue(program)
+            if(declConstValue==null) {
+                // move the vardecl (without value) to the scope and replace this with a regular assignment
+                decl.value = null
+                val target = AssignTarget(IdentifierReference(listOf(decl.name), decl.position), null, null, decl.position)
+                val assign = Assignment(target, declValue, decl.position)
+                return listOf(
+                        IAstModification.ReplaceNode(decl, assign, parent),
+                        IAstModification.InsertFirst(decl, decl.definingScope() as Node)
+                )
+            }
+        }
+        return noModifications
+    }
+
+    override fun after(whenStatement: WhenStatement, parent: Node): Iterable<IAstModification> {
+        val choices = whenStatement.choiceValues(program).sortedBy {
+            it.first?.first() ?: Int.MAX_VALUE
+        }
+        whenStatement.choices.clear()
+        choices.mapTo(whenStatement.choices) { it.second }
+        return noModifications
+    }
+
+    override fun before(assignment: Assignment, parent: Node): Iterable<IAstModification> {
+        val valueType = assignment.value.inferType(program)
+        val targetType = assignment.target.inferType(program, assignment)
+        if(valueType.istype(DataType.STRUCT) && targetType.istype(DataType.STRUCT)) {
+            val assignments = if (assignment.value is ArrayLiteralValue) {
+                flattenStructAssignmentFromStructLiteral(assignment, program)    //  'structvar = [ ..... ] '
+            } else {
+                flattenStructAssignmentFromIdentifier(assignment, program)    //   'structvar1 = structvar2'
+            }
+            if(assignments.isNotEmpty()) {
+                val modifications = mutableListOf<IAstModification>()
+                assignments.reversed().mapTo(modifications) { IAstModification.InsertAfter(assignment, it, parent) }
+                modifications.add(IAstModification.Remove(assignment, parent))
+                return modifications
+            }
+        }
+
+        return noModifications
+    }
+
+    override fun after(assignment: Assignment, parent: Node): Iterable<IAstModification> {
+        // rewrite in-place assignment expressions a bit so that the assignment target usually is the leftmost operand
+        val binExpr = assignment.value as? BinaryExpression
+        if(binExpr!=null) {
+            if(binExpr.left isSameAs assignment.target) {
+                // A = A <operator> 5, unchanged
+                return noModifications
+            }
+
+            if(binExpr.operator in associativeOperators) {
+                if (binExpr.right isSameAs assignment.target) {
+                    // A = v <associative-operator> A  ==>  A = A <associative-operator> v
+                    return listOf(IAstModification.SwapOperands(binExpr))
+                }
+
+                val leftBinExpr = binExpr.left as? BinaryExpression
+                if(leftBinExpr?.operator == binExpr.operator) {
+                    return if(leftBinExpr.left isSameAs assignment.target) {
+                        // A = (A <associative-operator> x) <same-operator> y ==> A = A <associative-operator> (x <same-operator> y)
+                        val newRight = BinaryExpression(leftBinExpr.right, binExpr.operator, binExpr.right, binExpr.position)
+                        val newValue = BinaryExpression(leftBinExpr.left, binExpr.operator, newRight, binExpr.position)
+                        listOf(IAstModification.ReplaceNode(binExpr, newValue, assignment))
+                    } else {
+                        // A = (x <associative-operator> A) <same-operator> y ==> A = A <associative-operator> (x <same-operator> y)
+                        val newRight = BinaryExpression(leftBinExpr.left, binExpr.operator, binExpr.right, binExpr.position)
+                        val newValue = BinaryExpression(leftBinExpr.right, binExpr.operator, newRight, binExpr.position)
+                        listOf(IAstModification.ReplaceNode(binExpr, newValue, assignment))
+                    }
+                }
+                val rightBinExpr = binExpr.right as? BinaryExpression
+                if(rightBinExpr?.operator == binExpr.operator) {
+                    return if(rightBinExpr.left isSameAs assignment.target) {
+                        // A = x <associative-operator> (A <same-operator> y) ==> A = A <associative-operator> (x <same-operator> y)
+                        val newRight = BinaryExpression(binExpr.left, binExpr.operator, rightBinExpr.right, binExpr.position)
+                        val newValue = BinaryExpression(rightBinExpr.left, binExpr.operator, newRight, binExpr.position)
+                        listOf(IAstModification.ReplaceNode(binExpr, newValue, assignment))
+                    } else {
+                        // A = x <associative-operator> (y <same-operator> A) ==> A = A <associative-operator> (x <same-operator> y)
+                        val newRight = BinaryExpression(binExpr.left, binExpr.operator, rightBinExpr.left, binExpr.position)
+                        val newValue = BinaryExpression(rightBinExpr.right, binExpr.operator, newRight, binExpr.position)
+                        listOf(IAstModification.ReplaceNode(binExpr, newValue, assignment))
+                    }
+                }
+            }
+        }
+
+        return noModifications
+    }
+
+    private fun flattenStructAssignmentFromStructLiteral(structAssignment: Assignment, program: Program): List<Assignment> {
+        val identifier = structAssignment.target.identifier!!
+        val identifierName = identifier.nameInSource.single()
+        val targetVar = identifier.targetVarDecl(program.namespace)!!
+        val struct = targetVar.struct!!
+
+        val slv = structAssignment.value as? ArrayLiteralValue
+        if(slv==null || slv.value.size != struct.numberOfElements)
+            throw FatalAstException("element count mismatch")
+
+        return struct.statements.zip(slv.value).map { (targetDecl, sourceValue) ->
+            targetDecl as VarDecl
+            val mangled = mangledStructMemberName(identifierName, targetDecl.name)
+            val idref = IdentifierReference(listOf(mangled), structAssignment.position)
+            val assign = Assignment(AssignTarget(idref, null, null, structAssignment.position),
+                    sourceValue, sourceValue.position)
+            assign.linkParents(structAssignment)
+            assign
+        }
+    }
+
+    private fun flattenStructAssignmentFromIdentifier(structAssignment: Assignment, program: Program): List<Assignment> {
+        val identifier = structAssignment.target.identifier!!
+        val identifierName = identifier.nameInSource.single()
+        val targetVar = identifier.targetVarDecl(program.namespace)!!
+        val struct = targetVar.struct!!
+        when (structAssignment.value) {
+            is IdentifierReference -> {
+                val sourceVar = (structAssignment.value as IdentifierReference).targetVarDecl(program.namespace)!!
+                if (sourceVar.struct == null)
+                    throw FatalAstException("can only assign arrays or structs to structs")
+                // struct memberwise copy
+                val sourceStruct = sourceVar.struct!!
+                if(sourceStruct!==targetVar.struct) {
+                    // structs are not the same in assignment
+                    return listOf()     // error will be printed elsewhere
+                }
+                return struct.statements.zip(sourceStruct.statements).map { member ->
+                    val targetDecl = member.first as VarDecl
+                    val sourceDecl = member.second as VarDecl
+                    if(targetDecl.name != sourceDecl.name)
+                        throw FatalAstException("struct member mismatch")
+                    val mangled = mangledStructMemberName(identifierName, targetDecl.name)
+                    val idref = IdentifierReference(listOf(mangled), structAssignment.position)
+                    val sourcemangled = mangledStructMemberName(sourceVar.name, sourceDecl.name)
+                    val sourceIdref = IdentifierReference(listOf(sourcemangled), structAssignment.position)
+                    val assign = Assignment(AssignTarget(idref, null, null, structAssignment.position), sourceIdref, member.second.position)
+                    assign.linkParents(structAssignment)
+                    assign
+                }
+            }
+            is ArrayLiteralValue -> {
+                throw IllegalArgumentException("not going to flatten a structLv assignment here")
+            }
+            else -> throw FatalAstException("strange struct value")
+        }
+    }
+
+}

compiler/src/prog8/ast/processing/TypecastsAdder.kt

@@ -0,0 +1,206 @@
+package prog8.ast.processing
+
+import prog8.ast.IFunctionCall
+import prog8.ast.INameScope
+import prog8.ast.Node
+import prog8.ast.Program
+import prog8.ast.base.*
+import prog8.ast.expressions.*
+import prog8.ast.statements.*
+import prog8.functions.BuiltinFunctions
+
+
+class TypecastsAdder(val program: Program, val errors: ErrorReporter) : AstWalker() {
+    /*
+     * Make sure any value assignments get the proper type casts if needed to cast them into the target variable's type.
+     * (this includes function call arguments)
+     */
+
+    private val noModifications = emptyList<IAstModification>()
+
+    override fun after(expr: BinaryExpression, parent: Node): Iterable<IAstModification> {
+        val leftDt = expr.left.inferType(program)
+        val rightDt = expr.right.inferType(program)
+        if(leftDt.isKnown && rightDt.isKnown && leftDt!=rightDt) {
+            // determine common datatype and add typecast as required to make left and right equal types
+            val (commonDt, toFix) = BinaryExpression.commonDatatype(leftDt.typeOrElse(DataType.STRUCT), rightDt.typeOrElse(DataType.STRUCT), expr.left, expr.right)
+            if(toFix!=null) {
+                return when {
+                    toFix===expr.left -> listOf(IAstModification.ReplaceNode(
+                            expr.left, TypecastExpression(expr.left, commonDt, true, expr.left.position), expr))
+                    toFix===expr.right -> listOf(IAstModification.ReplaceNode(
+                            expr.right, TypecastExpression(expr.right, commonDt, true, expr.right.position), expr))
+                    else -> throw FatalAstException("confused binary expression side")
+                }
+            }
+        }
+        return noModifications
+    }
+
+    override fun after(assignment: Assignment, parent: Node): Iterable<IAstModification> {
+        // see if a typecast is needed to convert the value's type into the proper target type
+        val valueItype = assignment.value.inferType(program)
+        val targetItype = assignment.target.inferType(program, assignment)
+        if(targetItype.isKnown && valueItype.isKnown) {
+            val targettype = targetItype.typeOrElse(DataType.STRUCT)
+            val valuetype = valueItype.typeOrElse(DataType.STRUCT)
+            if (valuetype != targettype) {
+                if (valuetype isAssignableTo targettype) {
+                    return listOf(IAstModification.ReplaceNode(
+                            assignment.value,
+                            TypecastExpression(assignment.value, targettype, true, assignment.value.position),
+                            assignment))
+                } else {
+                    fun castLiteral(cvalue: NumericLiteralValue): List<IAstModification.ReplaceNode> {
+                        val cast = cvalue.cast(targettype)
+                        return if(cast.isValid)
+                            listOf(IAstModification.ReplaceNode(cvalue, cast.valueOrZero(), cvalue.parent))
+                        else
+                            emptyList()
+                    }
+                    val cvalue = assignment.value.constValue(program)
+                    if(cvalue!=null) {
+                        val number = cvalue.number.toDouble()
+                        // more complex comparisons if the type is different, but the constant value is compatible
+                        if (valuetype == DataType.BYTE && targettype == DataType.UBYTE) {
+                            if(number>0)
+                                return castLiteral(cvalue)
+                        } else if (valuetype == DataType.WORD && targettype == DataType.UWORD) {
+                            if(number>0)
+                                return castLiteral(cvalue)
+                        } else if (valuetype == DataType.UBYTE && targettype == DataType.BYTE) {
+                            if(number<0x80)
+                                return castLiteral(cvalue)
+                        } else if (valuetype == DataType.UWORD && targettype == DataType.WORD) {
+                            if(number<0x8000)
+                                return castLiteral(cvalue)
+                        }
+                    }
+                }
+            }
+        }
+        return noModifications
+    }
+
+    override fun after(functionCallStatement: FunctionCallStatement, parent: Node): Iterable<IAstModification> {
+        return afterFunctionCallArgs(functionCallStatement, functionCallStatement.definingScope())
+    }
+
+    override fun after(functionCall: FunctionCall, parent: Node): Iterable<IAstModification> {
+        return afterFunctionCallArgs(functionCall, functionCall.definingScope())
+    }
+
+    private fun afterFunctionCallArgs(call: IFunctionCall, scope: INameScope): Iterable<IAstModification> {
+        // see if a typecast is needed to convert the arguments into the required parameter's type
+        val modifications = mutableListOf<IAstModification>()
+
+        when(val sub = call.target.targetStatement(scope)) {
+            is Subroutine -> {
+                for(arg in sub.parameters.zip(call.args.withIndex())) {
+                    val argItype = arg.second.value.inferType(program)
+                    if(argItype.isKnown) {
+                        val argtype = argItype.typeOrElse(DataType.STRUCT)
+                        val requiredType = arg.first.type
+                        if (requiredType != argtype) {
+                            if (argtype isAssignableTo requiredType) {
+                                modifications += IAstModification.ReplaceNode(
+                                        call.args[arg.second.index],
+                                        TypecastExpression(arg.second.value, requiredType, true, arg.second.value.position),
+                                        call as Node)
+                            } else if(requiredType == DataType.UWORD && argtype in PassByReferenceDatatypes) {
+                                // we allow STR/ARRAY values in place of UWORD parameters. Take their address instead.
+                                modifications += IAstModification.ReplaceNode(
+                                        call.args[arg.second.index],
+                                        AddressOf(arg.second.value as IdentifierReference, arg.second.value.position),
+                                        call as Node)
+                            } else if(arg.second.value is NumericLiteralValue) {
+                                val cast = (arg.second.value as NumericLiteralValue).cast(requiredType)
+                                if(cast.isValid)
+                                    modifications += IAstModification.ReplaceNode(
+                                            call.args[arg.second.index],
+                                            cast.valueOrZero(),
+                                            call as Node)
+                            }
+                        }
+                    }
+                }
+            }
+            is BuiltinFunctionStatementPlaceholder -> {
+                val func = BuiltinFunctions.getValue(sub.name)
+                for (arg in func.parameters.zip(call.args.withIndex())) {
+                    val argItype = arg.second.value.inferType(program)
+                    if (argItype.isKnown) {
+                        val argtype = argItype.typeOrElse(DataType.STRUCT)
+                        if (arg.first.possibleDatatypes.any { argtype == it })
+                            continue
+                        for (possibleType in arg.first.possibleDatatypes) {
+                            if (argtype isAssignableTo possibleType) {
+                                modifications += IAstModification.ReplaceNode(
+                                        call.args[arg.second.index],
+                                        TypecastExpression(arg.second.value, possibleType, true, arg.second.value.position),
+                                        call as Node)
+                            }
+                        }
+                    }
+                }
+            }
+            else -> { }
+        }
+
+        return modifications
+    }
+
+    override fun after(typecast: TypecastExpression, parent: Node): Iterable<IAstModification> {
+        // warn about any implicit type casts to Float, because that may not be intended
+        if(typecast.implicit && typecast.type in setOf(DataType.FLOAT, DataType.ARRAY_F)) {
+            errors.warn("integer implicitly converted to float. Suggestion: use float literals, add an explicit cast, or revert to integer arithmetic", typecast.position)
+        }
+        return noModifications
+    }
+
+    override fun after(memread: DirectMemoryRead, parent: Node): Iterable<IAstModification> {
+        // make sure the memory address is an uword
+        val dt = memread.addressExpression.inferType(program)
+        if(dt.isKnown && dt.typeOrElse(DataType.UWORD)!=DataType.UWORD) {
+            val typecast = (memread.addressExpression as? NumericLiteralValue)?.cast(DataType.UWORD)?.valueOrZero()
+                    ?: TypecastExpression(memread.addressExpression, DataType.UWORD, true, memread.addressExpression.position)
+            return listOf(IAstModification.ReplaceNode(memread.addressExpression, typecast, memread))
+        }
+        return noModifications
+    }
+
+    override fun after(memwrite: DirectMemoryWrite, parent: Node): Iterable<IAstModification> {
+        // make sure the memory address is an uword
+        val dt = memwrite.addressExpression.inferType(program)
+        if(dt.isKnown && dt.typeOrElse(DataType.UWORD)!=DataType.UWORD) {
+            val typecast = (memwrite.addressExpression as? NumericLiteralValue)?.cast(DataType.UWORD)?.valueOrZero()
+                    ?: TypecastExpression(memwrite.addressExpression, DataType.UWORD, true, memwrite.addressExpression.position)
+            return listOf(IAstModification.ReplaceNode(memwrite.addressExpression, typecast, memwrite))
+        }
+        return noModifications
+    }
+
+    override fun after(returnStmt: Return, parent: Node): Iterable<IAstModification> {
+        // add a typecast to the return type if it doesn't match the subroutine's signature
+        val returnValue = returnStmt.value
+        if(returnValue!=null) {
+            val subroutine = returnStmt.definingSubroutine()!!
+            if(subroutine.returntypes.size==1) {
+                val subReturnType = subroutine.returntypes.first()
+                if (returnValue.inferType(program).istype(subReturnType))
+                    return noModifications
+                if (returnValue is NumericLiteralValue) {
+                    val cast = returnValue.cast(subroutine.returntypes.single())
+                    if(cast.isValid)
+                        returnStmt.value = cast.valueOrZero()
+                } else {
+                    return listOf(IAstModification.ReplaceNode(
+                            returnValue,
+                            TypecastExpression(returnValue, subReturnType, true, returnValue.position),
+                            returnStmt))
+                }
+            }
+        }
+        return noModifications
+    }
+}

compiler/src/prog8/ast/processing/VariousCleanups.kt

@@ -0,0 +1,44 @@
+package prog8.ast.processing
+
+import prog8.ast.INameScope
+import prog8.ast.Node
+import prog8.ast.expressions.NumericLiteralValue
+import prog8.ast.expressions.TypecastExpression
+import prog8.ast.statements.AnonymousScope
+import prog8.ast.statements.NopStatement
+
+
+internal class VariousCleanups: AstWalker() {
+    private val noModifications = emptyList<IAstModification>()
+
+    override fun before(nopStatement: NopStatement, parent: Node): Iterable<IAstModification> {
+        return listOf(IAstModification.Remove(nopStatement, parent))
+    }
+
+    override fun before(scope: AnonymousScope, parent: Node): Iterable<IAstModification> {
+        return if(parent is INameScope)
+            listOf(ScopeFlatten(scope, parent as INameScope))
+        else
+            noModifications
+    }
+
+    class ScopeFlatten(val scope: AnonymousScope, val into: INameScope) : IAstModification {
+        override fun perform() {
+            val idx = into.statements.indexOf(scope)
+            if(idx>=0) {
+                into.statements.addAll(idx+1, scope.statements)
+                into.statements.remove(scope)
+            }
+        }
+    }
+
+    override fun before(typecast: TypecastExpression, parent: Node): Iterable<IAstModification> {
+        if(typecast.expression is NumericLiteralValue) {
+            val value = (typecast.expression as NumericLiteralValue).cast(typecast.type)
+            if(value.isValid)
+                return listOf(IAstModification.ReplaceNode(typecast, value.valueOrZero(), parent))
+        }
+
+        return noModifications
+    }
+}

compiler/src/prog8/ast/processing/VerifyFunctionArgTypes.kt

@@ -0,0 +1,61 @@
+package prog8.ast.processing
+
+import prog8.ast.IFunctionCall
+import prog8.ast.INameScope
+import prog8.ast.Program
+import prog8.ast.base.DataType
+import prog8.ast.expressions.FunctionCall
+import prog8.ast.statements.BuiltinFunctionStatementPlaceholder
+import prog8.ast.statements.FunctionCallStatement
+import prog8.ast.statements.Subroutine
+import prog8.compiler.CompilerException
+import prog8.functions.BuiltinFunctions
+
+class VerifyFunctionArgTypes(val program: Program) : IAstVisitor {
+
+    override fun visit(functionCall: FunctionCall) {
+        val error = checkTypes(functionCall as IFunctionCall, functionCall.definingScope(), program)
+        if(error!=null)
+            throw CompilerException(error)
+    }
+
+    override fun visit(functionCallStatement: FunctionCallStatement) {
+        val error = checkTypes(functionCallStatement as IFunctionCall, functionCallStatement.definingScope(), program)
+        if (error!=null)
+            throw CompilerException(error)
+    }
+
+    companion object {
+        fun checkTypes(call: IFunctionCall, scope: INameScope, program: Program): String? {
+            val argtypes = call.args.map { it.inferType(program).typeOrElse(DataType.STRUCT) }
+            val target = call.target.targetStatement(scope)
+            if (target is Subroutine) {
+                // asmsub types are not checked specifically at this time
+                if(call.args.size != target.parameters.size)
+                    return "invalid number of arguments"
+                val paramtypes = target.parameters.map { it.type }
+                val mismatch = argtypes.zip(paramtypes).indexOfFirst { it.first != it.second}
+                if(mismatch>=0) {
+                    val actual = argtypes[mismatch].toString()
+                    val expected = paramtypes[mismatch].toString()
+                    return "argument ${mismatch + 1} type mismatch, was: $actual expected: $expected"
+                }
+            }
+            else if (target is BuiltinFunctionStatementPlaceholder) {
+                val func = BuiltinFunctions.getValue(target.name)
+                if(call.args.size != func.parameters.size)
+                    return "invalid number of arguments"
+                val paramtypes = func.parameters.map { it.possibleDatatypes }
+                for (x in argtypes.zip(paramtypes).withIndex()) {
+                    if (x.value.first !in x.value.second) {
+                        val actual = x.value.first.toString()
+                        val expected = x.value.second.toString()
+                        return "argument ${x.index + 1} type mismatch, was: $actual expected: $expected"
+                    }
+                }
+            }
+
+            return null
+        }
+    }
+}

compiler/src/prog8/ast/statements/AstStatements.kt

@@ -0,0 +1,955 @@
+package prog8.ast.statements
+
+import prog8.ast.*
+import prog8.ast.base.*
+import prog8.ast.expressions.*
+import prog8.ast.processing.AstWalker
+import prog8.ast.processing.IAstVisitor
+
+
+sealed class Statement : Node {
+    abstract fun accept(visitor: IAstVisitor)
+    abstract fun accept(visitor: AstWalker, parent: Node)
+
+    fun makeScopedName(name: String): String {
+        // easy way out is to always return the full scoped name.
+        // it would be nicer to find only the minimal prefixed scoped name, but that's too much hassle for now.
+        // and like this, we can cache the name even,
+        // like in a lazy property on the statement object itself (label, subroutine, vardecl)
+        val scope = mutableListOf<String>()
+        var statementScope = this.parent
+        while(statementScope !is ParentSentinel && statementScope !is Module) {
+            if(statementScope is INameScope) {
+                scope.add(0, statementScope.name)
+            }
+            statementScope = statementScope.parent
+        }
+        if(name.isNotEmpty())
+            scope.add(name)
+        return scope.joinToString(".")
+    }
+
+    fun definingBlock(): Block {
+        if(this is Block)
+            return this
+        return findParentNode<Block>(this)!!
+    }
+}
+
+
+class BuiltinFunctionStatementPlaceholder(val name: String, override val position: Position) : Statement() {
+    override var parent: Node = ParentSentinel
+    override fun linkParents(parent: Node) {}
+    override fun accept(visitor: IAstVisitor) = visitor.visit(this)
+    override fun accept(visitor: AstWalker, parent: Node) = visitor.visit(this, parent)
+    override fun definingScope(): INameScope = BuiltinFunctionScopePlaceholder
+    override fun replaceChildNode(node: Node, replacement: Node) {
+        replacement.parent = this
+    }
+}
+
+data class RegisterOrStatusflag(val registerOrPair: RegisterOrPair?, val statusflag: Statusflag?, val stack: Boolean)
+
+class Block(override val name: String,
+            val address: Int?,
+            override var statements: MutableList<Statement>,
+            val isInLibrary: Boolean,
+            override val position: Position) : Statement(), INameScope {
+    override lateinit var parent: Node
+
+    override fun linkParents(parent: Node) {
+        this.parent = parent
+        statements.forEach {it.linkParents(this)}
+    }
+
+    override fun replaceChildNode(node: Node, replacement: Node) {
+        require(replacement is Statement)
+        val idx = statements.indexOfFirst { it ===node }
+        statements[idx] = replacement
+        replacement.parent = this
+    }
+
+    override fun accept(visitor: IAstVisitor) = visitor.visit(this)
+    override fun accept(visitor: AstWalker, parent: Node) = visitor.visit(this, parent)
+
+    override fun toString(): String {
+        return "Block(name=$name, address=$address, ${statements.size} statements)"
+    }
+
+    fun options() = statements.filter { it is Directive && it.directive == "%option" }.flatMap { (it as Directive).args }.map {it.name!!}.toSet()
+}
+
+data class Directive(val directive: String, val args: List<DirectiveArg>, override val position: Position) : Statement() {
+    override lateinit var parent: Node
+
+    override fun linkParents(parent: Node) {
+        this.parent = parent
+        args.forEach{it.linkParents(this)}
+    }
+
+    override fun replaceChildNode(node: Node, replacement: Node) = throw FatalAstException("can't replace here")
+    override fun accept(visitor: IAstVisitor) = visitor.visit(this)
+    override fun accept(visitor: AstWalker, parent: Node) = visitor.visit(this, parent)
+}
+
+data class DirectiveArg(val str: String?, val name: String?, val int: Int?, override val position: Position) : Node {
+    override lateinit var parent: Node
+
+    override fun linkParents(parent: Node) {
+        this.parent = parent
+    }
+    override fun replaceChildNode(node: Node, replacement: Node) = throw FatalAstException("can't replace here")
+}
+
+data class Label(val name: String, override val position: Position) : Statement() {
+    override lateinit var parent: Node
+
+    override fun linkParents(parent: Node) {
+        this.parent = parent
+    }
+
+    override fun replaceChildNode(node: Node, replacement: Node) = throw FatalAstException("can't replace here")
+    override fun accept(visitor: IAstVisitor) = visitor.visit(this)
+    override fun accept(visitor: AstWalker, parent: Node) = visitor.visit(this, parent)
+
+    override fun toString(): String {
+        return "Label(name=$name, pos=$position)"
+    }
+}
+
+open class Return(var value: Expression?, override val position: Position) : Statement() {
+    override lateinit var parent: Node
+
+    override fun linkParents(parent: Node) {
+        this.parent = parent
+        value?.linkParents(this)
+    }
+
+    override fun replaceChildNode(node: Node, replacement: Node) {
+        require(replacement is Expression)
+        value = replacement
+        replacement.parent = this
+    }
+
+    override fun accept(visitor: IAstVisitor) = visitor.visit(this)
+    override fun accept(visitor: AstWalker, parent: Node) = visitor.visit(this, parent)
+
+    override fun toString(): String {
+        return "Return($value, pos=$position)"
+    }
+}
+
+class Break(override val position: Position) : Statement() {
+    override lateinit var parent: Node
+
+    override fun linkParents(parent: Node) {
+        this.parent=parent
+    }
+
+    override fun replaceChildNode(node: Node, replacement: Node) = throw FatalAstException("can't replace here")
+    override fun accept(visitor: IAstVisitor) = visitor.visit(this)
+    override fun accept(visitor: AstWalker, parent: Node) = visitor.visit(this, parent)
+}
+
+
+enum class ZeropageWish {
+    REQUIRE_ZEROPAGE,
+    PREFER_ZEROPAGE,
+    DONTCARE,
+    NOT_IN_ZEROPAGE
+}
+
+
+open class VarDecl(val type: VarDeclType,
+              private val declaredDatatype: DataType,
+              val zeropage: ZeropageWish,
+              var arraysize: ArrayIndex?,
+              val name: String,
+              private val structName: String?,
+              var value: Expression?,
+              val isArray: Boolean,
+              val autogeneratedDontRemove: Boolean,
+              override val position: Position) : Statement() {
+    override lateinit var parent: Node
+    var struct: StructDecl? = null        // set later (because at parse time, we only know the name)
+        private set
+    var structHasBeenFlattened = false      // set later
+        private set
+
+    // prefix for literal values that are turned into a variable on the heap
+
+    companion object {
+        private var autoHeapValueSequenceNumber = 0
+
+        fun createAuto(string: StringLiteralValue): VarDecl {
+            val autoVarName = "auto_heap_value_${++autoHeapValueSequenceNumber}"
+            return VarDecl(VarDeclType.VAR, DataType.STR, ZeropageWish.NOT_IN_ZEROPAGE, null, autoVarName, null, string,
+                        isArray = false, autogeneratedDontRemove = true, position = string.position)
+        }
+
+        fun createAuto(array: ArrayLiteralValue): VarDecl {
+            val autoVarName = "auto_heap_value_${++autoHeapValueSequenceNumber}"
+            val declaredType = ArrayElementTypes.getValue(array.type.typeOrElse(DataType.STRUCT))
+            val arraysize = ArrayIndex.forArray(array)
+            return VarDecl(VarDeclType.VAR, declaredType, ZeropageWish.NOT_IN_ZEROPAGE, arraysize, autoVarName, null, array,
+                    isArray = true, autogeneratedDontRemove = true, position = array.position)
+        }
+
+        fun defaultZero(dt: DataType, position: Position) = when(dt) {
+            DataType.UBYTE -> NumericLiteralValue(DataType.UBYTE, 0,  position)
+            DataType.BYTE -> NumericLiteralValue(DataType.BYTE, 0,  position)
+            DataType.UWORD -> NumericLiteralValue(DataType.UWORD, 0, position)
+            DataType.WORD -> NumericLiteralValue(DataType.WORD, 0, position)
+            DataType.FLOAT -> NumericLiteralValue(DataType.FLOAT, 0.0, position)
+            else -> throw FatalAstException("can only determine default zero value for a numeric type")
+        }
+    }
+
+    val datatypeErrors = mutableListOf<SyntaxError>()       // don't crash at init time, report them in the AstChecker
+    val datatype =
+            if (!isArray) declaredDatatype
+            else when (declaredDatatype) {
+                DataType.UBYTE -> DataType.ARRAY_UB
+                DataType.BYTE -> DataType.ARRAY_B
+                DataType.UWORD -> DataType.ARRAY_UW
+                DataType.WORD -> DataType.ARRAY_W
+                DataType.FLOAT -> DataType.ARRAY_F
+                else -> {
+                    datatypeErrors.add(SyntaxError("array can only contain bytes/words/floats", position))
+                    DataType.ARRAY_UB
+                }
+            }
+
+    override fun linkParents(parent: Node) {
+        this.parent = parent
+        arraysize?.linkParents(this)
+        value?.linkParents(this)
+        if(structName!=null) {
+            val structStmt = definingScope().lookup(listOf(structName), this)
+            if(structStmt!=null)
+                struct = definingScope().lookup(listOf(structName), this) as StructDecl
+        }
+    }
+
+    override fun replaceChildNode(node: Node, replacement: Node) {
+        require(replacement is Expression && node===value)
+        value = replacement
+        replacement.parent = this
+    }
+
+    override fun accept(visitor: IAstVisitor) = visitor.visit(this)
+    override fun accept(visitor: AstWalker, parent: Node) = visitor.visit(this, parent)
+
+    override fun toString(): String {
+        return "VarDecl(name=$name, vartype=$type, datatype=$datatype, struct=$structName, value=$value, pos=$position)"
+    }
+
+    fun zeroElementValue() = defaultZero(declaredDatatype, position)
+
+    fun flattenStructMembers(): MutableList<Statement> {
+        val result = struct!!.statements.withIndex().map {
+            val member = it.value as VarDecl
+            val initvalue = if(value!=null) (value as ArrayLiteralValue).value[it.index] else null
+            VarDecl(
+                    VarDeclType.VAR,
+                    member.datatype,
+                    ZeropageWish.NOT_IN_ZEROPAGE,
+                    member.arraysize,
+                    mangledStructMemberName(name, member.name),
+                    struct!!.name,
+                    initvalue,
+                    member.isArray,
+                    true,
+                    member.position
+            )
+        }.toMutableList<Statement>()
+        structHasBeenFlattened = true
+        return result
+    }
+}
+
+// a vardecl used only for subroutine parameters
+class ParameterVarDecl(name: String, declaredDatatype: DataType, position: Position)
+    : VarDecl(VarDeclType.VAR, declaredDatatype, ZeropageWish.DONTCARE, null, name, null, null, false, true, position)
+
+
+class ArrayIndex(var index: Expression, override val position: Position) : Node {
+    override lateinit var parent: Node
+
+    override fun linkParents(parent: Node) {
+        this.parent = parent
+        index.linkParents(this)
+    }
+
+    override fun replaceChildNode(node: Node, replacement: Node) {
+        require(replacement is Expression && node===index)
+        index = replacement
+        replacement.parent = this
+    }
+
+    companion object {
+        fun forArray(v: ArrayLiteralValue): ArrayIndex {
+            return ArrayIndex(NumericLiteralValue.optimalNumeric(v.value.size, v.position), v.position)
+        }
+    }
+
+    fun accept(visitor: IAstVisitor) = index.accept(visitor)
+    fun accept(visitor: AstWalker, parent: Node) = index.accept(visitor, this)
+
+    override fun toString(): String {
+        return("ArrayIndex($index, pos=$position)")
+    }
+
+    fun constIndex() = (index as? NumericLiteralValue)?.number?.toInt()
+}
+
+open class Assignment(var target: AssignTarget, var value: Expression, override val position: Position) : Statement() {
+    override lateinit var parent: Node
+
+    override fun linkParents(parent: Node) {
+        this.parent = parent
+        this.target.linkParents(this)
+        value.linkParents(this)
+    }
+
+    override fun replaceChildNode(node: Node, replacement: Node) {
+        when {
+            node===target -> target = replacement as AssignTarget
+            node===value -> value = replacement as Expression
+            else -> throw FatalAstException("invalid replace")
+        }
+        replacement.parent = this
+    }
+
+    override fun accept(visitor: IAstVisitor) = visitor.visit(this)
+    override fun accept(visitor: AstWalker, parent: Node) = visitor.visit(this, parent)
+
+    override fun toString(): String {
+        return("Assignment(target: $target, value: $value, pos=$position)")
+    }
+
+    /**
+     * Is the assigment value an expression that references the assignment target itself?
+     * The expression can be a BinaryExpression, PrefixExpression or TypecastExpression (possibly with one sub-cast).
+     */
+    val isAugmentable: Boolean
+        get() {
+            val binExpr = value as? BinaryExpression
+            if(binExpr!=null) {
+                if(binExpr.left isSameAs target)
+                    return true  // A = A <operator> Something
+
+                if(binExpr.operator in associativeOperators) {
+                    if (binExpr.left !is BinaryExpression && binExpr.right isSameAs target)
+                        return true  // A = v <associative-operator> A
+
+                    val leftBinExpr = binExpr.left as? BinaryExpression
+                    if(leftBinExpr?.operator == binExpr.operator) {
+                        // one of these?
+                        // A = (A <associative-operator> x) <same-operator> y
+                        // A = (x <associative-operator> A) <same-operator> y
+                        // A = (x <associative-operator> y) <same-operator> A
+                        return leftBinExpr.left isSameAs target || leftBinExpr.right isSameAs target || binExpr.right isSameAs target
+                    }
+                    val rightBinExpr = binExpr.right as? BinaryExpression
+                    if(rightBinExpr?.operator == binExpr.operator) {
+                        // one of these?
+                        // A = y <associative-operator> (A <same-operator> x)
+                        // A = y <associative-operator> (x <same-operator> y)
+                        // A = A <associative-operator> (x <same-operator> y)
+                        return rightBinExpr.left isSameAs target || rightBinExpr.right isSameAs target || binExpr.left isSameAs target
+                    }
+                }
+            }
+
+            val prefixExpr = value as? PrefixExpression
+            if(prefixExpr!=null)
+                return prefixExpr.expression isSameAs target
+
+            val castExpr = value as? TypecastExpression
+            if(castExpr!=null) {
+                val subCast = castExpr.expression as? TypecastExpression
+                return if(subCast!=null) subCast.expression isSameAs target else castExpr.expression isSameAs target
+            }
+
+            return false
+        }
+}
+
+data class AssignTarget(var identifier: IdentifierReference?,
+                        var arrayindexed: ArrayIndexedExpression?,
+                        val memoryAddress: DirectMemoryWrite?,
+                        override val position: Position) : Node {
+    override lateinit var parent: Node
+
+    override fun linkParents(parent: Node) {
+        this.parent = parent
+        identifier?.linkParents(this)
+        arrayindexed?.linkParents(this)
+        memoryAddress?.linkParents(this)
+    }
+
+    override fun replaceChildNode(node: Node, replacement: Node) {
+        when {
+            node===identifier -> identifier = replacement as IdentifierReference
+            node===arrayindexed -> arrayindexed = replacement as ArrayIndexedExpression
+            else -> throw FatalAstException("invalid replace")
+        }
+        replacement.parent = this
+    }
+
+    fun accept(visitor: IAstVisitor) = visitor.visit(this)
+    fun accept(visitor: AstWalker, parent: Node) = visitor.visit(this, parent)
+
+    companion object {
+        fun fromExpr(expr: Expression): AssignTarget {
+            return when (expr) {
+                is IdentifierReference -> AssignTarget(expr, null, null, expr.position)
+                is ArrayIndexedExpression -> AssignTarget(null, expr, null, expr.position)
+                is DirectMemoryRead -> AssignTarget(null, null, DirectMemoryWrite(expr.addressExpression, expr.position), expr.position)
+                else -> throw FatalAstException("invalid expression object $expr")
+            }
+        }
+    }
+
+    fun inferType(program: Program, stmt: Statement): InferredTypes.InferredType {
+        if(identifier!=null) {
+            val symbol = program.namespace.lookup(identifier!!.nameInSource, stmt) ?: return InferredTypes.unknown()
+            if (symbol is VarDecl) return InferredTypes.knownFor(symbol.datatype)
+        }
+
+        if(arrayindexed!=null) {
+            return arrayindexed!!.inferType(program)
+        }
+
+        if(memoryAddress!=null)
+            return InferredTypes.knownFor(DataType.UBYTE)
+
+        return InferredTypes.unknown()
+    }
+
+    fun toExpression(): Expression {
+        return when {
+            identifier!=null -> identifier!!
+            arrayindexed!=null -> arrayindexed!!
+            memoryAddress!=null -> DirectMemoryRead(memoryAddress.addressExpression, memoryAddress.position)
+            else -> throw FatalAstException("invalid assignmenttarget $this")
+        }
+    }
+
+    infix fun isSameAs(value: Expression): Boolean {
+        return when {
+            this.memoryAddress!=null -> {
+                // if the target is a memory write, and the value is a memory read, they're the same if the address matches
+                if(value is DirectMemoryRead)
+                    this.memoryAddress.addressExpression isSameAs value.addressExpression
+                else
+                    false
+            }
+            this.identifier!=null -> value is IdentifierReference && value.nameInSource==identifier!!.nameInSource
+            this.arrayindexed!=null -> value is ArrayIndexedExpression &&
+                    value.identifier.nameInSource==arrayindexed!!.identifier.nameInSource &&
+                    value.arrayspec.constIndex()!=null &&
+                    arrayindexed!!.arrayspec.constIndex()!=null &&
+                    value.arrayspec.constIndex()==arrayindexed!!.arrayspec.constIndex()
+            else -> false
+        }
+    }
+
+    fun isSameAs(other: AssignTarget, program: Program): Boolean {
+        if(this===other)
+            return true
+        if(this.identifier!=null && other.identifier!=null)
+            return this.identifier!!.nameInSource==other.identifier!!.nameInSource
+        if(this.memoryAddress!=null && other.memoryAddress!=null) {
+            val addr1 = this.memoryAddress.addressExpression.constValue(program)
+            val addr2 = other.memoryAddress.addressExpression.constValue(program)
+            return addr1!=null && addr2!=null && addr1==addr2
+        }
+        if(this.arrayindexed!=null && other.arrayindexed!=null) {
+            if(this.arrayindexed!!.identifier.nameInSource == other.arrayindexed!!.identifier.nameInSource) {
+                val x1 = this.arrayindexed!!.arrayspec.index.constValue(program)
+                val x2 = other.arrayindexed!!.arrayspec.index.constValue(program)
+                return x1!=null && x2!=null && x1==x2
+            }
+        }
+        return false
+    }
+
+    fun isNotMemory(namespace: INameScope): Boolean {
+        if(this.memoryAddress!=null)
+            return false
+        if(this.arrayindexed!=null) {
+            val targetStmt = this.arrayindexed!!.identifier.targetVarDecl(namespace)
+            if(targetStmt!=null)
+                return targetStmt.type!= VarDeclType.MEMORY
+        }
+        if(this.identifier!=null) {
+            val targetStmt = this.identifier!!.targetVarDecl(namespace)
+            if(targetStmt!=null)
+                return targetStmt.type!= VarDeclType.MEMORY
+        }
+        return false
+    }
+}
+
+class PostIncrDecr(var target: AssignTarget, val operator: String, override val position: Position) : Statement() {
+    override lateinit var parent: Node
+
+    override fun linkParents(parent: Node) {
+        this.parent = parent
+        target.linkParents(this)
+    }
+
+    override fun replaceChildNode(node: Node, replacement: Node) {
+        require(replacement is AssignTarget && node===target)
+        target = replacement
+        replacement.parent = this
+    }
+
+    override fun accept(visitor: IAstVisitor) = visitor.visit(this)
+    override fun accept(visitor: AstWalker, parent: Node) = visitor.visit(this, parent)
+
+    override fun toString(): String {
+        return "PostIncrDecr(op: $operator, target: $target, pos=$position)"
+    }
+}
+
+class Jump(val address: Int?,
+           val identifier: IdentifierReference?,
+           val generatedLabel: String?,             // used in code generation scenarios
+           override val position: Position) : Statement() {
+    override lateinit var parent: Node
+
+    override fun linkParents(parent: Node) {
+        this.parent = parent
+        identifier?.linkParents(this)
+    }
+
+    override fun replaceChildNode(node: Node, replacement: Node) = throw FatalAstException("can't replace here")
+    override fun accept(visitor: IAstVisitor) = visitor.visit(this)
+    override fun accept(visitor: AstWalker, parent: Node) = visitor.visit(this, parent)
+
+    override fun toString(): String {
+        return "Jump(addr: $address, identifier: $identifier, label: $generatedLabel;  pos=$position)"
+    }
+}
+
+class FunctionCallStatement(override var target: IdentifierReference,
+                            override var args: MutableList<Expression>,
+                            val void: Boolean,
+                            override val position: Position) : Statement(), IFunctionCall {
+    override lateinit var parent: Node
+
+    override fun linkParents(parent: Node) {
+        this.parent = parent
+        target.linkParents(this)
+        args.forEach { it.linkParents(this) }
+    }
+
+    override fun replaceChildNode(node: Node, replacement: Node) {
+        if(node===target)
+            target = replacement as IdentifierReference
+        else {
+            val idx = args.indexOfFirst { it===node }
+            args[idx] = replacement as Expression
+        }
+        replacement.parent = this
+    }
+
+    override fun accept(visitor: IAstVisitor) = visitor.visit(this)
+    override fun accept(visitor: AstWalker, parent: Node) = visitor.visit(this, parent)
+
+    override fun toString(): String {
+        return "FunctionCallStatement(target=$target, pos=$position)"
+    }
+}
+
+class InlineAssembly(val assembly: String, override val position: Position) : Statement() {
+    override lateinit var parent: Node
+
+    override fun linkParents(parent: Node) {
+        this.parent = parent
+    }
+
+    override fun replaceChildNode(node: Node, replacement: Node) = throw FatalAstException("can't replace here")
+    override fun accept(visitor: IAstVisitor) = visitor.visit(this)
+    override fun accept(visitor: AstWalker, parent: Node) = visitor.visit(this, parent)
+}
+
+class AnonymousScope(override var statements: MutableList<Statement>,
+                     override val position: Position) : INameScope, Statement() {
+    override val name: String
+    override lateinit var parent: Node
+
+    companion object {
+        private var sequenceNumber = 1
+    }
+
+    init {
+        name = "<anon-$sequenceNumber>"     // make sure it's an invalid soruce code identifier so user source code can never produce it
+        sequenceNumber++
+    }
+
+    override fun linkParents(parent: Node) {
+        this.parent = parent
+        statements.forEach { it.linkParents(this) }
+    }
+
+    override fun replaceChildNode(node: Node, replacement: Node) {
+        require(replacement is Statement)
+        val idx = statements.indexOfFirst { it===node }
+        statements[idx] = replacement
+        replacement.parent = this
+    }
+
+    override fun accept(visitor: IAstVisitor) = visitor.visit(this)
+    override fun accept(visitor: AstWalker, parent: Node) = visitor.visit(this, parent)
+}
+
+class NopStatement(override val position: Position): Statement() {
+    override lateinit var parent: Node
+
+    override fun linkParents(parent: Node) {
+        this.parent = parent
+    }
+
+    override fun replaceChildNode(node: Node, replacement: Node) = throw FatalAstException("can't replace here")
+    override fun accept(visitor: IAstVisitor) = visitor.visit(this)
+    override fun accept(visitor: AstWalker, parent: Node) = visitor.visit(this, parent)
+}
+
+// the subroutine class covers both the normal user-defined subroutines,
+// and also the predefined/ROM/register-based subroutines.
+// (multiple return types can only occur for the latter type)
+class Subroutine(override val name: String,
+                 val parameters: List<SubroutineParameter>,
+                 val returntypes: List<DataType>,
+                 val asmParameterRegisters: List<RegisterOrStatusflag>,
+                 val asmReturnvaluesRegisters: List<RegisterOrStatusflag>,
+                 val asmClobbers: Set<CpuRegister>,
+                 val asmAddress: Int?,
+                 val isAsmSubroutine: Boolean,
+                 override var statements: MutableList<Statement>,
+                 override val position: Position) : Statement(), INameScope {
+
+    override lateinit var parent: Node
+    val scopedname: String by lazy { makeScopedName(name) }
+
+    override fun linkParents(parent: Node) {
+        this.parent = parent
+        parameters.forEach { it.linkParents(this) }
+        statements.forEach { it.linkParents(this) }
+    }
+
+    override fun replaceChildNode(node: Node, replacement: Node) {
+        require(replacement is Statement)
+        val idx = statements.indexOfFirst { it===node }
+        statements[idx] = replacement
+        replacement.parent = this
+    }
+
+    override fun accept(visitor: IAstVisitor) = visitor.visit(this)
+    override fun accept(visitor: AstWalker, parent: Node) = visitor.visit(this, parent)
+
+    override fun toString(): String {
+        return "Subroutine(name=$name, parameters=$parameters, returntypes=$returntypes, ${statements.size} statements, address=$asmAddress)"
+    }
+
+    fun regXasResult() = asmReturnvaluesRegisters.any { it.registerOrPair in setOf(RegisterOrPair.X, RegisterOrPair.AX, RegisterOrPair.XY) }
+
+    fun amountOfRtsInAsm(): Int = statements
+            .asSequence()
+            .filter { it is InlineAssembly }
+            .map { (it as InlineAssembly).assembly }
+            .count { " rti" in it || "\trti" in it || " rts" in it || "\trts" in it || " jmp" in it || "\tjmp" in it }
+}
+
+
+open class SubroutineParameter(val name: String,
+                               val type: DataType,
+                               override val position: Position) : Node {
+    override lateinit var parent: Node
+
+    override fun linkParents(parent: Node) {
+        this.parent = parent
+    }
+
+    override fun replaceChildNode(node: Node, replacement: Node) {
+        throw FatalAstException("can't replace anything in a subroutineparameter node")
+    }
+}
+
+class IfStatement(var condition: Expression,
+                  var truepart: AnonymousScope,
+                  var elsepart: AnonymousScope,
+                  override val position: Position) : Statement() {
+    override lateinit var parent: Node
+
+    override fun linkParents(parent: Node) {
+        this.parent = parent
+        condition.linkParents(this)
+        truepart.linkParents(this)
+        elsepart.linkParents(this)
+    }
+
+    override fun replaceChildNode(node: Node, replacement: Node) {
+        when {
+            node===condition -> condition = replacement as Expression
+            node===truepart -> truepart = replacement as AnonymousScope
+            node===elsepart -> elsepart = replacement as AnonymousScope
+            else -> throw FatalAstException("invalid replace")
+        }
+        replacement.parent = this
+    }
+
+    override fun accept(visitor: IAstVisitor) = visitor.visit(this)
+    override fun accept(visitor: AstWalker, parent: Node) = visitor.visit(this, parent)
+
+}
+
+class BranchStatement(var condition: BranchCondition,
+                      var truepart: AnonymousScope,
+                      var elsepart: AnonymousScope,
+                      override val position: Position) : Statement() {
+    override lateinit var parent: Node
+
+    override fun linkParents(parent: Node) {
+        this.parent = parent
+        truepart.linkParents(this)
+        elsepart.linkParents(this)
+    }
+
+    override fun replaceChildNode(node: Node, replacement: Node) {
+        when {
+            node===truepart -> truepart = replacement as AnonymousScope
+            node===elsepart -> elsepart = replacement as AnonymousScope
+            else -> throw FatalAstException("invalid replace")
+        }
+        replacement.parent = this
+    }
+
+    override fun accept(visitor: IAstVisitor) = visitor.visit(this)
+    override fun accept(visitor: AstWalker, parent: Node) = visitor.visit(this, parent)
+
+}
+
+class ForLoop(var loopVar: IdentifierReference,
+              var iterable: Expression,
+              var body: AnonymousScope,
+              override val position: Position) : Statement() {
+    override lateinit var parent: Node
+
+    override fun linkParents(parent: Node) {
+        this.parent=parent
+        loopVar.linkParents(this)
+        iterable.linkParents(this)
+        body.linkParents(this)
+    }
+
+    override fun replaceChildNode(node: Node, replacement: Node) {
+        when {
+            node===loopVar -> loopVar = replacement as IdentifierReference
+            node===iterable -> iterable = replacement as Expression
+            node===body -> body = replacement as AnonymousScope
+            else -> throw FatalAstException("invalid replace")
+        }
+        replacement.parent = this
+    }
+
+    override fun accept(visitor: IAstVisitor) = visitor.visit(this)
+    override fun accept(visitor: AstWalker, parent: Node) = visitor.visit(this, parent)
+
+    override fun toString(): String {
+        return "ForLoop(loopVar: $loopVar, iterable: $iterable, pos=$position)"
+    }
+
+    fun loopVarDt(program: Program) = loopVar.inferType(program)
+}
+
+class WhileLoop(var condition: Expression,
+                var body: AnonymousScope,
+                override val position: Position) : Statement() {
+    override lateinit var parent: Node
+
+    override fun linkParents(parent: Node) {
+        this.parent = parent
+        condition.linkParents(this)
+        body.linkParents(this)
+    }
+
+    override fun replaceChildNode(node: Node, replacement: Node) {
+        when {
+            node===condition -> condition = replacement as Expression
+            node===body -> body = replacement as AnonymousScope
+            else -> throw FatalAstException("invalid replace")
+        }
+        replacement.parent = this
+    }
+
+    override fun accept(visitor: IAstVisitor) = visitor.visit(this)
+    override fun accept(visitor: AstWalker, parent: Node) = visitor.visit(this, parent)
+}
+
+class RepeatLoop(var iterations: Expression?, var body: AnonymousScope, override val position: Position) : Statement() {
+    override lateinit var parent: Node
+
+    override fun linkParents(parent: Node) {
+        this.parent = parent
+        iterations?.linkParents(this)
+        body.linkParents(this)
+    }
+
+    override fun replaceChildNode(node: Node, replacement: Node) {
+        when {
+            node===iterations -> iterations = replacement as Expression
+            node===body -> body = replacement as AnonymousScope
+            else -> throw FatalAstException("invalid replace")
+        }
+        replacement.parent = this
+    }
+
+    override fun accept(visitor: IAstVisitor) = visitor.visit(this)
+    override fun accept(visitor: AstWalker, parent: Node) = visitor.visit(this, parent)
+}
+
+class UntilLoop(var body: AnonymousScope,
+                var untilCondition: Expression,
+                override val position: Position) : Statement() {
+    override lateinit var parent: Node
+
+    override fun linkParents(parent: Node) {
+        this.parent = parent
+        untilCondition.linkParents(this)
+        body.linkParents(this)
+    }
+
+    override fun replaceChildNode(node: Node, replacement: Node) {
+        when {
+            node===untilCondition -> untilCondition = replacement as Expression
+            node===body -> body = replacement as AnonymousScope
+            else -> throw FatalAstException("invalid replace")
+        }
+        replacement.parent = this
+    }
+
+    override fun accept(visitor: IAstVisitor) = visitor.visit(this)
+    override fun accept(visitor: AstWalker, parent: Node) = visitor.visit(this, parent)
+}
+
+class WhenStatement(var condition: Expression,
+                    var choices: MutableList<WhenChoice>,
+                    override val position: Position): Statement() {
+    override lateinit var parent: Node
+
+    override fun linkParents(parent: Node) {
+        this.parent = parent
+        condition.linkParents(this)
+        choices.forEach { it.linkParents(this) }
+    }
+
+    override fun replaceChildNode(node: Node, replacement: Node) {
+        if(node===condition)
+            condition = replacement as Expression
+        else {
+            val idx = choices.withIndex().find { it.value===node }!!.index
+            choices[idx] = replacement as WhenChoice
+        }
+        replacement.parent = this
+    }
+
+    fun choiceValues(program: Program): List<Pair<List<Int>?, WhenChoice>> {
+        // only gives sensible results when the choices are all valid (constant integers)
+        val result = mutableListOf<Pair<List<Int>?, WhenChoice>>()
+        for(choice in choices) {
+            if(choice.values==null)
+                result.add(null to choice)
+            else {
+                val values = choice.values!!.map { it.constValue(program)?.number?.toInt() }
+                if(values.contains(null))
+                    result.add(null to choice)
+                else
+                    result.add(values.filterNotNull() to choice)
+            }
+        }
+        return result
+    }
+
+    override fun accept(visitor: IAstVisitor) = visitor.visit(this)
+    override fun accept(visitor: AstWalker, parent: Node) = visitor.visit(this, parent)
+}
+
+class WhenChoice(var values: List<Expression>?,           // if null,  this is the 'else' part
+                 var statements: AnonymousScope,
+                 override val position: Position) : Node {
+    override lateinit var parent: Node
+
+    override fun linkParents(parent: Node) {
+        values?.forEach { it.linkParents(this) }
+        statements.linkParents(this)
+        this.parent = parent
+    }
+
+    override fun replaceChildNode(node: Node, replacement: Node) {
+        require(replacement is AnonymousScope && node===statements)
+        statements = replacement
+        replacement.parent = this
+    }
+
+    override fun toString(): String {
+        return "Choice($values at $position)"
+    }
+
+    fun accept(visitor: IAstVisitor) = visitor.visit(this)
+    fun accept(visitor: AstWalker, parent: Node) = visitor.visit(this, parent)
+}
+
+
+class StructDecl(override val name: String,
+                 override var statements: MutableList<Statement>,      // actually, only vardecls here
+                 override val position: Position): Statement(), INameScope {
+
+    override lateinit var parent: Node
+
+    override fun linkParents(parent: Node) {
+        this.parent = parent
+        this.statements.forEach { it.linkParents(this) }
+    }
+
+    override fun replaceChildNode(node: Node, replacement: Node) {
+        require(replacement is Statement)
+        val idx = statements.indexOfFirst { it===node }
+        statements[idx] = replacement
+        replacement.parent = this
+    }
+
+    val numberOfElements: Int
+        get() = this.statements.size
+
+    override fun accept(visitor: IAstVisitor) = visitor.visit(this)
+    override fun accept(visitor: AstWalker, parent: Node) = visitor.visit(this, parent)
+
+    fun nameOfFirstMember() = (statements.first() as VarDecl).name
+}
+
+class DirectMemoryWrite(var addressExpression: Expression, override val position: Position) : Node {
+    override lateinit var parent: Node
+
+    override fun linkParents(parent: Node) {
+        this.parent = parent
+        this.addressExpression.linkParents(this)
+    }
+
+    override fun replaceChildNode(node: Node, replacement: Node) {
+        require(replacement is Expression && node===addressExpression)
+        addressExpression = replacement
+        replacement.parent = this
+    }
+
+    override fun toString(): String {
+        return "DirectMemoryWrite($addressExpression)"
+    }
+
+    fun accept(visitor: IAstVisitor) = visitor.visit(this)
+    fun accept(visitor: AstWalker, parent: Node) = visitor.visit(this, parent)
+}

compiler/src/prog8/compiler/AssemblyError.kt

@@ -0,0 +1,3 @@
+package prog8.compiler
+
+internal class AssemblyError(msg: String) : RuntimeException(msg)

compiler/src/prog8/compiler/BeforeAsmGenerationAstChanger.kt

@@ -0,0 +1,132 @@
+package prog8.compiler
+
+import prog8.ast.Node
+import prog8.ast.Program
+import prog8.ast.base.*
+import prog8.ast.expressions.*
+import prog8.ast.processing.AstWalker
+import prog8.ast.processing.IAstModification
+import prog8.ast.statements.*
+
+
+internal class BeforeAsmGenerationAstChanger(val program: Program, val errors: ErrorReporter) : AstWalker() {
+
+    private val noModifications = emptyList<IAstModification>()
+
+    override fun after(decl: VarDecl, parent: Node): Iterable<IAstModification> {
+        if (decl.value == null && decl.type == VarDeclType.VAR && decl.datatype in NumericDatatypes) {
+            // a numeric vardecl without an initial value is initialized with zero.
+            decl.value = decl.zeroElementValue()
+        }
+        return noModifications
+    }
+
+    override fun after(assignment: Assignment, parent: Node): Iterable<IAstModification> {
+        // Try to replace A = B <operator> Something  by A= B, A = A <operator> Something
+        // this triggers the more efficent augmented assignment code generation more often.
+        if(!assignment.isAugmentable
+                && assignment.target.identifier != null
+                && assignment.target.isNotMemory(program.namespace)) {
+            val binExpr = assignment.value as? BinaryExpression
+            if(binExpr!=null && binExpr.operator !in comparisonOperators) {
+                if(binExpr.left !is BinaryExpression) {
+                    val assignLeft = Assignment(assignment.target, binExpr.left, assignment.position)
+                    return listOf(
+                            IAstModification.InsertBefore(assignment, assignLeft, parent),
+                            IAstModification.ReplaceNode(binExpr.left, assignment.target.toExpression(), binExpr))
+                }
+            }
+        }
+        return noModifications
+    }
+
+    override fun after(scope: AnonymousScope, parent: Node): Iterable<IAstModification> {
+        val decls = scope.statements.filterIsInstance<VarDecl>()
+        val sub = scope.definingSubroutine()
+        if (sub != null) {
+            val existingVariables = sub.statements.filterIsInstance<VarDecl>().associateBy { it.name }
+            var conflicts = false
+            decls.forEach {
+                val existing = existingVariables[it.name]
+                if (existing != null) {
+                    errors.err("variable ${it.name} already defined in subroutine ${sub.name} at ${existing.position}", it.position)
+                    conflicts = true
+                }
+            }
+            if (!conflicts) {
+                val numericVarsWithValue = decls.filter { it.value != null && it.datatype in NumericDatatypes }
+                return numericVarsWithValue.map {
+                    val initValue = it.value!!  // assume here that value has always been set by now
+                    it.value = null     // make sure no value init assignment for this vardecl will be created later (would be superfluous)
+                    val target = AssignTarget(IdentifierReference(listOf(it.name), it.position), null, null, it.position)
+                    val assign = Assignment(target, initValue, it.position)
+                    initValue.parent = assign
+                    IAstModification.InsertFirst(assign, scope)
+                } +  decls.map { IAstModification.ReplaceNode(it, NopStatement(it.position), scope) } +
+                     decls.map { IAstModification.InsertFirst(it, sub) }    // move it up to the subroutine
+            }
+        }
+        return noModifications
+    }
+
+    override fun after(subroutine: Subroutine, parent: Node): Iterable<IAstModification> {
+        // add the implicit return statement at the end (if it's not there yet), but only if it's not a kernel routine.
+        // and if an assembly block doesn't contain a rts/rti, and some other situations.
+        val mods = mutableListOf<IAstModification>()
+        val returnStmt = Return(null, subroutine.position)
+        if (subroutine.asmAddress == null
+                && subroutine.statements.isNotEmpty()
+                && subroutine.amountOfRtsInAsm() == 0
+                && subroutine.statements.lastOrNull { it !is VarDecl } !is Return
+                && subroutine.statements.last() !is Subroutine) {
+            mods += IAstModification.InsertLast(returnStmt, subroutine)
+        }
+
+        // precede a subroutine with a return to avoid falling through into the subroutine from code above it
+        val outerScope = subroutine.definingScope()
+        val outerStatements = outerScope.statements
+        val subroutineStmtIdx = outerStatements.indexOf(subroutine)
+        if (subroutineStmtIdx > 0
+                && outerStatements[subroutineStmtIdx - 1] !is Jump
+                && outerStatements[subroutineStmtIdx - 1] !is Subroutine
+                && outerStatements[subroutineStmtIdx - 1] !is Return
+                && outerScope !is Block) {
+            mods += IAstModification.InsertAfter(outerStatements[subroutineStmtIdx - 1], returnStmt, outerScope as Node)
+        }
+
+        return mods
+    }
+
+    override fun after(typecast: TypecastExpression, parent: Node): Iterable<IAstModification> {
+        // see if we can remove superfluous typecasts (outside of expressions)
+        // such as casting byte<->ubyte,  word<->uword
+        // Also the special typecast of a reference type (str, array) to an UWORD will be changed into address-of.
+        val sourceDt = typecast.expression.inferType(program).typeOrElse(DataType.STRUCT)
+        if (typecast.type in ByteDatatypes && sourceDt in ByteDatatypes
+                || typecast.type in WordDatatypes && sourceDt in WordDatatypes) {
+            if(typecast.parent !is Expression) {
+                return listOf(IAstModification.ReplaceNode(typecast, typecast.expression, parent))
+            }
+        }
+
+
+        // Note: for various reasons (most importantly, code simplicity), the code generator assumes/requires
+        // that the types of assignment values and their target are the same,
+        // and that the types of both operands of a binaryexpression node are the same.
+        // So, it is not easily possible to remove the typecasts that are there to make these conditions true.
+
+        if(sourceDt in PassByReferenceDatatypes) {
+            if(typecast.type==DataType.UWORD) {
+                return listOf(IAstModification.ReplaceNode(
+                        typecast,
+                        AddressOf(typecast.expression as IdentifierReference, typecast.position),
+                        parent
+                ))
+            } else {
+                errors.err("cannot cast pass-by-reference value to type ${typecast.type} (only to UWORD)", typecast.position)
+            }
+        }
+
+        return noModifications
+    }
+}

compiler/src/prog8/compiler/Main.kt

@@ -0,0 +1,212 @@
+package prog8.compiler
+
+import prog8.ast.AstToSourceCode
+import prog8.ast.Program
+import prog8.ast.base.*
+import prog8.ast.statements.Directive
+import prog8.compiler.target.CompilationTarget
+import prog8.optimizer.UnusedCodeRemover
+import prog8.optimizer.constantFold
+import prog8.optimizer.optimizeStatements
+import prog8.optimizer.simplifyExpressions
+import prog8.parser.ModuleImporter
+import prog8.parser.ParsingFailedError
+import prog8.parser.moduleName
+import java.nio.file.Path
+import kotlin.system.measureTimeMillis
+
+
+class CompilationResult(val success: Boolean,
+                        val programAst: Program,
+                        val programName: String,
+                        val importedFiles: List<Path>)
+
+
+fun compileProgram(filepath: Path,
+                   optimize: Boolean,
+                   writeAssembly: Boolean,
+                   outputDir: Path): CompilationResult {
+    var programName = ""
+    lateinit var programAst: Program
+    lateinit var importedFiles: List<Path>
+    val errors = ErrorReporter()
+
+    try {
+        val totalTime = measureTimeMillis {
+            // import main module and everything it needs
+            val (ast, compilationOptions, imported) = parseImports(filepath, errors)
+            programAst = ast
+            importedFiles = imported
+            processAst(programAst, errors, compilationOptions)
+            if (optimize)
+                optimizeAst(programAst, errors)
+            postprocessAst(programAst, errors, compilationOptions)
+
+            // printAst(programAst)
+
+            if(writeAssembly)
+                programName = writeAssembly(programAst, errors, outputDir, optimize, compilationOptions)
+        }
+        System.out.flush()
+        System.err.flush()
+        println("\nTotal compilation+assemble time: ${totalTime / 1000.0} sec.")
+        return CompilationResult(true, programAst, programName, importedFiles)
+
+    } catch (px: ParsingFailedError) {
+        System.err.print("\u001b[91m")  // bright red
+        System.err.println(px.message)
+        System.err.print("\u001b[0m")  // reset
+    } catch (ax: AstException) {
+        System.err.print("\u001b[91m")  // bright red
+        System.err.println(ax.toString())
+        System.err.print("\u001b[0m")  // reset
+    } catch (x: Exception) {
+        print("\u001b[91m")  // bright red
+        println("\n* internal error *")
+        print("\u001b[0m")  // reset
+        System.out.flush()
+        throw x
+    } catch (x: NotImplementedError) {
+        print("\u001b[91m")  // bright red
+        println("\n* internal error: missing feature/code *")
+        print("\u001b[0m")  // reset
+        System.out.flush()
+        throw x
+    }
+
+    return CompilationResult(false, Program("failed", mutableListOf()), programName, emptyList())
+}
+
+private fun parseImports(filepath: Path, errors: ErrorReporter): Triple<Program, CompilationOptions, List<Path>> {
+    println("Parsing...")
+    val importer = ModuleImporter()
+    val programAst = Program(moduleName(filepath.fileName), mutableListOf())
+    importer.importModule(programAst, filepath)
+    errors.handle()
+
+    val importedFiles = programAst.modules.filter { !it.source.startsWith("@embedded@") }.map { it.source }
+
+    val compilerOptions = determineCompilationOptions(programAst)
+    if (compilerOptions.launcher == LauncherType.BASIC && compilerOptions.output != OutputType.PRG)
+        throw ParsingFailedError("${programAst.modules.first().position} BASIC launcher requires output type PRG.")
+
+    // depending on the mach9ine and compiler options we may have to include some libraries
+    CompilationTarget.machine.importLibs(compilerOptions, importer, programAst)
+
+    // always import prog8lib and math
+    importer.importLibraryModule(programAst, "math")
+    importer.importLibraryModule(programAst, "prog8lib")
+    errors.handle()
+    return Triple(programAst, compilerOptions, importedFiles)
+}
+
+private fun determineCompilationOptions(program: Program): CompilationOptions {
+    val mainModule = program.modules.first()
+    val outputType = (mainModule.statements.singleOrNull { it is Directive && it.directive == "%output" }
+            as? Directive)?.args?.single()?.name?.toUpperCase()
+    val launcherType = (mainModule.statements.singleOrNull { it is Directive && it.directive == "%launcher" }
+            as? Directive)?.args?.single()?.name?.toUpperCase()
+    mainModule.loadAddress = (mainModule.statements.singleOrNull { it is Directive && it.directive == "%address" }
+            as? Directive)?.args?.single()?.int ?: 0
+    val zpoption: String? = (mainModule.statements.singleOrNull { it is Directive && it.directive == "%zeropage" }
+            as? Directive)?.args?.single()?.name?.toUpperCase()
+    val allOptions = program.modules.flatMap { it.statements }.filter { it is Directive && it.directive == "%option" }.flatMap { (it as Directive).args }.toSet()
+    val floatsEnabled = allOptions.any { it.name == "enable_floats" }
+    val zpType: ZeropageType =
+            if (zpoption == null)
+                if(floatsEnabled) ZeropageType.FLOATSAFE else ZeropageType.KERNALSAFE
+            else
+                try {
+                    ZeropageType.valueOf(zpoption)
+                } catch (x: IllegalArgumentException) {
+                    ZeropageType.KERNALSAFE
+                    // error will be printed by the astchecker
+                }
+    val zpReserved = mainModule.statements
+            .asSequence()
+            .filter { it is Directive && it.directive == "%zpreserved" }
+            .map { (it as Directive).args }
+            .map { it[0].int!!..it[1].int!! }
+            .toList()
+
+    return CompilationOptions(
+            if (outputType == null) OutputType.PRG else OutputType.valueOf(outputType),
+            if (launcherType == null) LauncherType.BASIC else LauncherType.valueOf(launcherType),
+            zpType, zpReserved, floatsEnabled
+    )
+}
+
+private fun processAst(programAst: Program, errors: ErrorReporter, compilerOptions: CompilationOptions) {
+    // perform initial syntax checks and processings
+    println("Processing...")
+    programAst.checkIdentifiers(errors)
+    errors.handle()
+    programAst.constantFold(errors)
+    errors.handle()
+    programAst.reorderStatements()
+    programAst.addTypecasts(errors)
+    errors.handle()
+    programAst.variousCleanups()
+    programAst.checkValid(compilerOptions, errors)
+    errors.handle()
+    programAst.checkIdentifiers(errors)
+    errors.handle()
+}
+
+private fun optimizeAst(programAst: Program, errors: ErrorReporter) {
+    // optimize the parse tree
+    println("Optimizing...")
+    while (true) {
+        // keep optimizing expressions and statements until no more steps remain
+        val optsDone1 = programAst.simplifyExpressions()
+        val optsDone2 = programAst.optimizeStatements(errors)
+        programAst.constantFold(errors) // because simplified statements and expressions could give rise to more constants that can be folded away:
+        errors.handle()
+        if (optsDone1 + optsDone2 == 0)
+            break
+    }
+
+    val remover = UnusedCodeRemover(errors)
+    remover.visit(programAst)
+    remover.applyModifications()
+    errors.handle()
+}
+
+private fun postprocessAst(programAst: Program, errors: ErrorReporter, compilerOptions: CompilationOptions) {
+    programAst.addTypecasts(errors)
+    errors.handle()
+    programAst.variousCleanups()
+    programAst.checkValid(compilerOptions, errors)          // check if final tree is still valid
+    errors.handle()
+    programAst.checkRecursion(errors)         // check if there are recursive subroutine calls
+    errors.handle()
+    programAst.verifyFunctionArgTypes()
+}
+
+private fun writeAssembly(programAst: Program, errors: ErrorReporter, outputDir: Path,
+                          optimize: Boolean, compilerOptions: CompilationOptions): String {
+    // asm generation directly from the Ast,
+    programAst.processAstBeforeAsmGeneration(errors)
+    errors.handle()
+
+    // printAst(programAst)
+
+    CompilationTarget.machine.initializeZeropage(compilerOptions)
+    val assembly = CompilationTarget.asmGenerator(
+            programAst,
+            errors,
+            CompilationTarget.machine.zeropage,
+            compilerOptions,
+            outputDir).compileToAssembly(optimize)
+    assembly.assemble(compilerOptions)
+    errors.handle()
+    return assembly.name
+}
+
+fun printAst(programAst: Program) {
+    println()
+    val printer = AstToSourceCode(::print, programAst)
+    printer.visit(programAst)
+    println()
+}
+

compiler/src/prog8/compiler/Zeropage.kt

@@ -1,33 +1,43 @@
 package prog8.compiler
 
-import prog8.ast.*
+import prog8.ast.base.*
 
 
 class ZeropageDepletedError(message: String) : Exception(message)
 
 
-abstract class Zeropage(private val options: CompilationOptions) {
+abstract class Zeropage(protected val options: CompilationOptions) {
+
+    abstract val SCRATCH_B1 : Int      // temp storage for a single byte
+    abstract val SCRATCH_REG : Int     // temp storage for a register
+    abstract val SCRATCH_REG_X : Int   // temp storage for register X (the evaluation stack pointer)
+    abstract val SCRATCH_W1 : Int      // temp storage 1 for a word  $fb+$fc
+    abstract val SCRATCH_W2 : Int      // temp storage 2 for a word  $fb+$fc
+
 
     private val allocations = mutableMapOf<Int, Pair<String, DataType>>()
     val free = mutableListOf<Int>()     // subclasses must set this to the appropriate free locations.
 
     val allowedDatatypes = NumericDatatypes
 
-    fun available() = free.size
+    fun available() = if(options.zeropage==ZeropageType.DONTUSE) 0 else free.size
 
-    fun allocate(scopedname: String, datatype: DataType, position: Position?): Int {
+    fun allocate(scopedname: String, datatype: DataType, position: Position?, errors: ErrorReporter): Int {
-        assert(scopedname.isEmpty() || !allocations.values.any { it.first==scopedname } ) {"same scopedname can't be allocated twice"}
+        assert(scopedname.isEmpty() || !allocations.values.any { it.first==scopedname } ) {"scopedname can't be allocated twice"}
+
+        if(options.zeropage==ZeropageType.DONTUSE)
+            throw CompilerException("zero page usage has been disabled")
 
         val size =
                 when (datatype) {
-                    DataType.UBYTE, DataType.BYTE -> 1
+                    in ByteDatatypes -> 1
-                    DataType.UWORD, DataType.WORD -> 2
+                    in WordDatatypes -> 2
                     DataType.FLOAT -> {
                         if (options.floats) {
                             if(position!=null)
-                                printWarning("allocated a large value (float) in zeropage", position)
+                                errors.warn("allocated a large value (float) in zeropage", position)
                             else
-                                printWarning("$scopedname: allocated a large value (float) in zeropage")
+                                errors.warn("$scopedname: allocated a large value (float) in zeropage", position ?: Position.DUMMY)
                             5
                         } else throw CompilerException("floating point option not enabled")
                     }
@@ -36,13 +46,13 @@ abstract class Zeropage(private val options: CompilationOptions) {
 
         if(free.size > 0) {
             if(size==1) {
-                for(candidate in free.min()!! .. free.max()!!+1) {
+                for(candidate in free.minOrNull()!! .. free.maxOrNull()!!+1) {
                     if(loneByte(candidate))
                         return makeAllocation(candidate, 1, datatype, scopedname)
                 }
                 return makeAllocation(free[0], 1, datatype, scopedname)
             }
-            for(candidate in free.min()!! .. free.max()!!+1) {
+            for(candidate in free.minOrNull()!! .. free.maxOrNull()!!+1) {
                 if (sequentialFree(candidate, size))
                     return makeAllocation(candidate, size, datatype, scopedname)
             }
@@ -61,4 +71,12 @@ abstract class Zeropage(private val options: CompilationOptions) {
 
     private fun loneByte(address: Int) = address in free && address-1 !in free && address+1 !in free
     private fun sequentialFree(address: Int, size: Int) = free.containsAll((address until address+size).toList())
+
+    enum class ExitProgramStrategy {
+        CLEAN_EXIT,
+        SYSTEM_RESET
+    }
+
+    abstract val exitProgramStrategy: ExitProgramStrategy
+
 }

compiler/src/prog8/compiler/intermediate/Instruction.kt

@@ -1,41 +0,0 @@
-package prog8.compiler.intermediate
-
-import prog8.stackvm.Syscall
-
-open class Instruction(val opcode: Opcode,
-                       val arg: Value? = null,
-                       val arg2: Value? = null,
-                       val callLabel: String? = null,
-                       val callLabel2: String? = null)
-{
-    lateinit var next: Instruction
-    var nextAlt: Instruction? = null
-
-    override fun toString(): String {
-        val argStr = arg?.toString() ?: ""
-        val result =
-                when {
-                    opcode==Opcode.LINE -> "_line  $callLabel"
-                    opcode==Opcode.INLINE_ASSEMBLY -> "inline_assembly"
-                    opcode==Opcode.SYSCALL -> {
-                        val syscall = Syscall.values().find { it.callNr==arg!!.numericValue() }
-                        "syscall  $syscall"
-                    }
-                    opcode in opcodesWithVarArgument -> {
-                        // opcodes that manipulate a variable
-                        "${opcode.toString().toLowerCase()}  ${callLabel?:""}  ${callLabel2?:""}".trimEnd()
-                    }
-                    callLabel==null -> "${opcode.toString().toLowerCase()}  $argStr"
-                    else -> "${opcode.toString().toLowerCase()}  $callLabel  $argStr"
-                }
-                .trimEnd()
-
-        return "    $result"
-    }
-}
-
-class LabelInstr(val name: String, val asmProc: Boolean) : Instruction(Opcode.NOP, null, null) {
-    override fun toString(): String {
-        return "\n$name:"
-    }
-}

compiler/src/prog8/compiler/intermediate/IntermediateProgram.kt

@@ -1,504 +0,0 @@
-package prog8.compiler.intermediate
-
-import prog8.ast.*
-import prog8.compiler.CompilerException
-import prog8.compiler.HeapValues
-import prog8.compiler.Zeropage
-import prog8.compiler.ZeropageDepletedError
-import java.io.PrintStream
-import java.nio.file.Path
-
-
-class IntermediateProgram(val name: String, var loadAddress: Int, val heap: HeapValues, val importedFrom: Path) {
-
-    class ProgramBlock(val scopedname: String,
-                       val shortname: String,
-                       var address: Int?,
-                       val instructions: MutableList<Instruction> = mutableListOf(),
-                       val variables: MutableMap<String, Value> = mutableMapOf(),
-                       val memoryPointers: MutableMap<String, Pair<Int, DataType>> = mutableMapOf(),
-                       val labels: MutableMap<String, Instruction> = mutableMapOf(),
-                       val force_output: Boolean)
-    {
-        val numVariables: Int
-            get() { return variables.size }
-        val numInstructions: Int
-            get() { return instructions.filter { it.opcode!= Opcode.LINE }.size }
-        val variablesMarkedForZeropage: MutableSet<String> = mutableSetOf()
-    }
-
-    val allocatedZeropageVariables = mutableMapOf<String, Pair<Int, DataType>>()
-    val blocks = mutableListOf<ProgramBlock>()
-    val memory = mutableMapOf<Int, List<Value>>()
-    private lateinit var currentBlock: ProgramBlock
-
-    val numVariables: Int
-        get() = blocks.sumBy { it.numVariables }
-    val numInstructions: Int
-        get() = blocks.sumBy { it.numInstructions }
-
-    fun allocateZeropage(zeropage: Zeropage) {
-        // allocates all @zp marked variables on the zeropage (for all blocks, as long as there is space in the ZP)
-        var notAllocated = 0
-        for(block in blocks) {
-            val zpVariables = block.variables.filter { it.key in block.variablesMarkedForZeropage }
-            if (zpVariables.isNotEmpty()) {
-                for (variable in zpVariables) {
-                    try {
-                        val address = zeropage.allocate(variable.key, variable.value.type, null)
-                        allocatedZeropageVariables[variable.key] = Pair(address, variable.value.type)
-                    } catch (x: ZeropageDepletedError) {
-                        printWarning(x.toString() + " variable ${variable.key} type ${variable.value.type}")
-                        notAllocated++
-                    }
-                }
-            }
-        }
-        if(notAllocated>0)
-            printWarning("$notAllocated variables marked for Zeropage could not be allocated there")
-    }
-
-    fun optimize() {
-        println("Optimizing stackVM code...")
-        // remove nops (that are not a label)
-        for (blk in blocks) {
-            blk.instructions.removeIf { it.opcode== Opcode.NOP && it !is LabelInstr }
-        }
-
-        optimizeDataConversionAndUselessDiscards()
-        optimizeVariableCopying()
-        optimizeMultipleSequentialLineInstrs()
-        optimizeCallReturnIntoJump()
-        optimizeConditionalBranches()
-        // todo: add more optimizations to stackvm code
-
-        optimizeRemoveNops()    //  must be done as the last step
-        optimizeMultipleSequentialLineInstrs()      // once more
-        optimizeRemoveNops()    // once more
-    }
-
-    private fun optimizeConditionalBranches() {
-        // conditional branches that consume the value on the stack
-        // sometimes these are just constant values, so we can statically determine the branch
-        // or, they are preceded by a NOT instruction so we can simply remove that and flip the branch condition
-        val pushvalue = setOf(Opcode.PUSH_BYTE, Opcode.PUSH_WORD)
-        val notvalue = setOf(Opcode.NOT_BYTE, Opcode.NOT_WORD)
-        val branchOpcodes = setOf(Opcode.JZ, Opcode.JNZ, Opcode.JZW, Opcode.JNZW)
-        for(blk in blocks) {
-            val instructionsToReplace = mutableMapOf<Int, Instruction>()
-            blk.instructions.asSequence().withIndex().filter {it.value.opcode!=Opcode.LINE}.windowed(2).toList().forEach {
-                if (it[1].value.opcode in branchOpcodes) {
-                    if (it[0].value.opcode in pushvalue) {
-                        val value = it[0].value.arg!!.asBooleanValue
-                        instructionsToReplace[it[0].index] = Instruction(Opcode.NOP)
-                        val replacement: Instruction =
-                                if (value) {
-                                    when (it[1].value.opcode) {
-                                        Opcode.JNZ -> Instruction(Opcode.JUMP, callLabel = it[1].value.callLabel)
-                                        Opcode.JNZW -> Instruction(Opcode.JUMP, callLabel = it[1].value.callLabel)
-                                        else -> Instruction(Opcode.NOP)
-                                    }
-                                } else {
-                                    when (it[1].value.opcode) {
-                                        Opcode.JZ -> Instruction(Opcode.JUMP, callLabel = it[1].value.callLabel)
-                                        Opcode.JZW -> Instruction(Opcode.JUMP, callLabel = it[1].value.callLabel)
-                                        else -> Instruction(Opcode.NOP)
-                                    }
-                                }
-                        instructionsToReplace[it[1].index] = replacement
-                    }
-                    else if (it[0].value.opcode in notvalue) {
-                        instructionsToReplace[it[0].index] = Instruction(Opcode.NOP)
-                        val replacement: Instruction =
-                                when (it[1].value.opcode) {
-                                    Opcode.JZ -> Instruction(Opcode.JNZ, callLabel = it[1].value.callLabel)
-                                    Opcode.JZW -> Instruction(Opcode.JNZW, callLabel = it[1].value.callLabel)
-                                    Opcode.JNZ -> Instruction(Opcode.JZ, callLabel = it[1].value.callLabel)
-                                    Opcode.JNZW -> Instruction(Opcode.JZW, callLabel = it[1].value.callLabel)
-                                    else -> Instruction(Opcode.NOP)
-                                }
-                        instructionsToReplace[it[1].index] = replacement
-                    }
-                }
-            }
-
-            for (rins in instructionsToReplace) {
-                blk.instructions[rins.key] = rins.value
-            }
-        }
-    }
-
-    private fun optimizeRemoveNops() {
-        // remove nops (that are not a label)
-        for (blk in blocks)
-            blk.instructions.removeIf { it.opcode== Opcode.NOP && it !is LabelInstr }
-    }
-
-    private fun optimizeCallReturnIntoJump() {
-        // replaces call X followed by return, by jump X
-        for(blk in blocks) {
-            val instructionsToReplace = mutableMapOf<Int, Instruction>()
-
-            blk.instructions.asSequence().withIndex().filter {it.value.opcode!=Opcode.LINE}.windowed(2).toList().forEach {
-                if(it[0].value.opcode==Opcode.CALL && it[1].value.opcode==Opcode.RETURN) {
-                    instructionsToReplace[it[1].index] = Instruction(Opcode.JUMP, callLabel = it[0].value.callLabel)
-                    instructionsToReplace[it[0].index] = Instruction(Opcode.NOP)
-                }
-            }
-
-            for (rins in instructionsToReplace) {
-                blk.instructions[rins.key] = rins.value
-            }
-        }
-    }
-
-    private fun optimizeMultipleSequentialLineInstrs() {
-        for(blk in blocks) {
-            val instructionsToReplace = mutableMapOf<Int, Instruction>()
-
-            blk.instructions.asSequence().withIndex().windowed(2).toList().forEach {
-                if (it[0].value.opcode == Opcode.LINE && it[1].value.opcode == Opcode.LINE)
-                    instructionsToReplace[it[0].index] = Instruction(Opcode.NOP)
-            }
-
-            for (rins in instructionsToReplace) {
-                blk.instructions[rins.key] = rins.value
-            }
-        }
-    }
-
-    private fun optimizeVariableCopying() {
-        for(blk in blocks) {
-
-            val instructionsToReplace = mutableMapOf<Int, Instruction>()
-
-            blk.instructions.asSequence().withIndex().windowed(2).toList().forEach {
-                when (it[0].value.opcode) {
-                    Opcode.PUSH_VAR_BYTE ->
-                        if (it[1].value.opcode == Opcode.POP_VAR_BYTE) {
-                            if (it[0].value.callLabel == it[1].value.callLabel) {
-                                instructionsToReplace[it[0].index] = Instruction(Opcode.NOP)
-                                instructionsToReplace[it[1].index] = Instruction(Opcode.NOP)
-                            }
-                        }
-                    Opcode.PUSH_VAR_WORD ->
-                        if (it[1].value.opcode == Opcode.POP_VAR_WORD) {
-                            if (it[0].value.callLabel == it[1].value.callLabel) {
-                                instructionsToReplace[it[0].index] = Instruction(Opcode.NOP)
-                                instructionsToReplace[it[1].index] = Instruction(Opcode.NOP)
-                            }
-                        }
-                    Opcode.PUSH_VAR_FLOAT ->
-                        if (it[1].value.opcode == Opcode.POP_VAR_FLOAT) {
-                            if (it[0].value.callLabel == it[1].value.callLabel) {
-                                instructionsToReplace[it[0].index] = Instruction(Opcode.NOP)
-                                instructionsToReplace[it[1].index] = Instruction(Opcode.NOP)
-                            }
-                        }
-                    Opcode.PUSH_MEM_B, Opcode.PUSH_MEM_UB ->
-                        if(it[1].value.opcode == Opcode.POP_MEM_BYTE) {
-                            if(it[0].value.arg == it[1].value.arg) {
-                                instructionsToReplace[it[0].index] = Instruction(Opcode.NOP)
-                                instructionsToReplace[it[1].index] = Instruction(Opcode.NOP)
-                            }
-                        }
-                    Opcode.PUSH_MEM_W, Opcode.PUSH_MEM_UW ->
-                        if(it[1].value.opcode == Opcode.POP_MEM_WORD) {
-                            if(it[0].value.arg == it[1].value.arg) {
-                                instructionsToReplace[it[0].index] = Instruction(Opcode.NOP)
-                                instructionsToReplace[it[1].index] = Instruction(Opcode.NOP)
-                            }
-                        }
-                    Opcode.PUSH_MEM_FLOAT ->
-                        if(it[1].value.opcode == Opcode.POP_MEM_FLOAT) {
-                            if(it[0].value.arg == it[1].value.arg) {
-                                instructionsToReplace[it[0].index] = Instruction(Opcode.NOP)
-                                instructionsToReplace[it[1].index] = Instruction(Opcode.NOP)
-                            }
-                        }
-                    else -> {}
-                }
-            }
-
-            for (rins in instructionsToReplace) {
-                blk.instructions[rins.key] = rins.value
-            }
-        }
-    }
-
-    private fun optimizeDataConversionAndUselessDiscards() {
-        // - push value followed by a data type conversion -> push the value in the correct type and remove the conversion
-        // - push something followed by a discard -> remove both
-        val instructionsToReplace = mutableMapOf<Int, Instruction>()
-
-        fun optimizeDiscardAfterPush(index0: Int, index1: Int, ins1: Instruction) {
-            if (ins1.opcode == Opcode.DISCARD_FLOAT || ins1.opcode == Opcode.DISCARD_WORD || ins1.opcode == Opcode.DISCARD_BYTE) {
-                instructionsToReplace[index0] = Instruction(Opcode.NOP)
-                instructionsToReplace[index1] = Instruction(Opcode.NOP)
-            }
-        }
-
-        fun optimizeFloatConversion(index0: Int, index1: Int, ins1: Instruction) {
-            when (ins1.opcode) {
-                Opcode.DISCARD_FLOAT -> {
-                    instructionsToReplace[index0] = Instruction(Opcode.NOP)
-                    instructionsToReplace[index1] = Instruction(Opcode.NOP)
-                }
-                Opcode.DISCARD_BYTE, Opcode.DISCARD_WORD -> throw CompilerException("invalid discard type following a float")
-                else -> throw CompilerException("invalid conversion opcode ${ins1.opcode} following a float")
-            }
-        }
-
-        fun optimizeWordConversion(index0: Int, ins0: Instruction, index1: Int, ins1: Instruction) {
-            when (ins1.opcode) {
-                Opcode.CAST_UW_TO_B, Opcode.CAST_W_TO_B -> {
-                    val ins = Instruction(Opcode.PUSH_BYTE, ins0.arg!!.cast(DataType.BYTE))
-                    instructionsToReplace[index0] = ins
-                    instructionsToReplace[index1] = Instruction(Opcode.NOP)
-                }
-                Opcode.CAST_W_TO_UB, Opcode.CAST_UW_TO_UB -> {
-                    val ins = Instruction(Opcode.PUSH_BYTE, Value(DataType.UBYTE, ins0.arg!!.integerValue() and 255))
-                    instructionsToReplace[index0] = ins
-                    instructionsToReplace[index1] = Instruction(Opcode.NOP)
-                }
-                Opcode.MSB -> {
-                    val ins = Instruction(Opcode.PUSH_BYTE, Value(DataType.UBYTE, ins0.arg!!.integerValue() ushr 8 and 255))
-                    instructionsToReplace[index0] = ins
-                    instructionsToReplace[index1] = Instruction(Opcode.NOP)
-                }
-                Opcode.CAST_W_TO_F, Opcode.CAST_UW_TO_F -> {
-                    val ins = Instruction(Opcode.PUSH_FLOAT, Value(DataType.FLOAT, ins0.arg!!.integerValue().toDouble()))
-                    instructionsToReplace[index0] = ins
-                    instructionsToReplace[index1] = Instruction(Opcode.NOP)
-                }
-                Opcode.CAST_UW_TO_W -> {
-                    val cv = ins0.arg!!.cast(DataType.WORD)
-                    instructionsToReplace[index0] = Instruction(Opcode.PUSH_WORD, cv)
-                    instructionsToReplace[index1] = Instruction(Opcode.NOP)
-                }
-                Opcode.CAST_W_TO_UW -> {
-                    val cv = ins0.arg!!.cast(DataType.UWORD)
-                    instructionsToReplace[index0] = Instruction(Opcode.PUSH_WORD, cv)
-                    instructionsToReplace[index1] = Instruction(Opcode.NOP)
-                }
-                Opcode.DISCARD_WORD -> {
-                    instructionsToReplace[index0] = Instruction(Opcode.NOP)
-                    instructionsToReplace[index1] = Instruction(Opcode.NOP)
-                }
-                Opcode.DISCARD_BYTE, Opcode.DISCARD_FLOAT -> throw CompilerException("invalid discard type following a byte")
-                else -> throw CompilerException("invalid conversion opcode ${ins1.opcode} following a word")
-            }
-        }
-
-        fun optimizeByteConversion(index0: Int, ins0: Instruction, index1: Int, ins1: Instruction) {
-            when (ins1.opcode) {
-                Opcode.CAST_B_TO_UB, Opcode.CAST_UB_TO_B,
-                Opcode.CAST_W_TO_B, Opcode.CAST_W_TO_UB,
-                Opcode.CAST_UW_TO_B, Opcode.CAST_UW_TO_UB -> instructionsToReplace[index1] = Instruction(Opcode.NOP)
-                Opcode.MSB -> throw CompilerException("msb of a byte")
-                Opcode.CAST_UB_TO_UW -> {
-                    val ins = Instruction(Opcode.PUSH_WORD, Value(DataType.UWORD, ins0.arg!!.integerValue()))
-                    instructionsToReplace[index0] = ins
-                    instructionsToReplace[index1] = Instruction(Opcode.NOP)
-                }
-                Opcode.CAST_B_TO_W -> {
-                    val ins = Instruction(Opcode.PUSH_WORD, Value(DataType.WORD, ins0.arg!!.integerValue()))
-                    instructionsToReplace[index0] = ins
-                    instructionsToReplace[index1] = Instruction(Opcode.NOP)
-                }
-                Opcode.CAST_B_TO_UW -> {
-                    val ins = Instruction(Opcode.PUSH_WORD, ins0.arg!!.cast(DataType.UWORD))
-                    instructionsToReplace[index0] = ins
-                    instructionsToReplace[index1] = Instruction(Opcode.NOP)
-                }
-                Opcode.CAST_UB_TO_W -> {
-                    val ins = Instruction(Opcode.PUSH_WORD, ins0.arg!!.cast(DataType.WORD))
-                    instructionsToReplace[index0] = ins
-                    instructionsToReplace[index1] = Instruction(Opcode.NOP)
-                }
-                Opcode.CAST_B_TO_F, Opcode.CAST_UB_TO_F-> {
-                    val ins = Instruction(Opcode.PUSH_FLOAT, Value(DataType.FLOAT, ins0.arg!!.integerValue().toDouble()))
-                    instructionsToReplace[index0] = ins
-                    instructionsToReplace[index1] = Instruction(Opcode.NOP)
-                }
-                Opcode.CAST_W_TO_F, Opcode.CAST_UW_TO_F-> throw CompilerException("invalid conversion following a byte")
-                Opcode.DISCARD_BYTE -> {
-                    instructionsToReplace[index0] = Instruction(Opcode.NOP)
-                    instructionsToReplace[index1] = Instruction(Opcode.NOP)
-                }
-                Opcode.DISCARD_WORD, Opcode.DISCARD_FLOAT -> throw CompilerException("invalid discard type following a byte")
-                else -> throw CompilerException("invalid conversion opcode ${ins1.opcode}")
-            }
-        }
-
-        for(blk in blocks) {
-            instructionsToReplace.clear()
-
-            val typeConversionOpcodes = setOf(
-                    Opcode.MSB,
-                    Opcode.MKWORD,
-                    Opcode.CAST_UB_TO_B,
-                    Opcode.CAST_UB_TO_UW,
-                    Opcode.CAST_UB_TO_W,
-                    Opcode.CAST_UB_TO_F,
-                    Opcode.CAST_B_TO_UB,
-                    Opcode.CAST_B_TO_UW,
-                    Opcode.CAST_B_TO_W,
-                    Opcode.CAST_B_TO_F,
-                    Opcode.CAST_UW_TO_UB,
-                    Opcode.CAST_UW_TO_B,
-                    Opcode.CAST_UW_TO_W,
-                    Opcode.CAST_UW_TO_F,
-                    Opcode.CAST_W_TO_UB,
-                    Opcode.CAST_W_TO_B,
-                    Opcode.CAST_W_TO_UW,
-                    Opcode.CAST_W_TO_F,
-                    Opcode.CAST_F_TO_UB,
-                    Opcode.CAST_F_TO_B,
-                    Opcode.CAST_F_TO_UW,
-                    Opcode.CAST_F_TO_W,
-                    Opcode.DISCARD_BYTE,
-                    Opcode.DISCARD_WORD,
-                    Opcode.DISCARD_FLOAT
-            )
-            blk.instructions.asSequence().withIndex().windowed(2).toList().forEach {
-                if (it[1].value.opcode in typeConversionOpcodes) {
-                    when (it[0].value.opcode) {
-                        Opcode.PUSH_BYTE -> optimizeByteConversion(it[0].index, it[0].value, it[1].index, it[1].value)
-                        Opcode.PUSH_WORD -> optimizeWordConversion(it[0].index, it[0].value, it[1].index, it[1].value)
-                        Opcode.PUSH_FLOAT -> optimizeFloatConversion(it[0].index, it[1].index, it[1].value)
-                        Opcode.PUSH_VAR_FLOAT,
-                        Opcode.PUSH_VAR_WORD,
-                        Opcode.PUSH_VAR_BYTE,
-                        Opcode.PUSH_MEM_B, Opcode.PUSH_MEM_UB,
-                        Opcode.PUSH_MEM_W, Opcode.PUSH_MEM_UW,
-                        Opcode.PUSH_MEM_FLOAT -> optimizeDiscardAfterPush(it[0].index, it[1].index, it[1].value)
-                        else -> {
-                        }
-                    }
-                }
-            }
-
-            for (rins in instructionsToReplace) {
-                blk.instructions[rins.key] = rins.value
-            }
-        }
-    }
-
-    fun variable(scopedname: String, decl: VarDecl) {
-        when(decl.type) {
-            VarDeclType.VAR -> {
-                val value = when(decl.datatype) {
-                    DataType.UBYTE, DataType.BYTE, DataType.UWORD, DataType.WORD, DataType.FLOAT -> Value(decl.datatype, (decl.value as LiteralValue).asNumericValue!!)
-                    DataType.STR, DataType.STR_P, DataType.STR_S, DataType.STR_PS -> {
-                        val litval = (decl.value as LiteralValue)
-                        if(litval.heapId==null)
-                            throw CompilerException("string should already be in the heap")
-                        Value(decl.datatype, litval.heapId)
-                    }
-                    DataType.ARRAY_B, DataType.ARRAY_W,
-                    DataType.ARRAY_UB, DataType.ARRAY_UW, DataType.ARRAY_F -> {
-                        val litval = (decl.value as LiteralValue)
-                        if(litval.heapId==null)
-                            throw CompilerException("array should already be in the heap")
-                        Value(decl.datatype, litval.heapId)
-                    }
-                }
-                currentBlock.variables[scopedname] = value
-                if(decl.zeropage)
-                    currentBlock.variablesMarkedForZeropage.add(scopedname)
-            }
-            VarDeclType.MEMORY -> {
-                // note that constants are all folded away, but assembly code may still refer to them
-                val lv = decl.value as LiteralValue
-                if(lv.type!=DataType.UWORD && lv.type!=DataType.UBYTE)
-                    throw CompilerException("expected integer memory address $lv")
-                currentBlock.memoryPointers[scopedname] = Pair(lv.asIntegerValue!!, decl.datatype)
-            }
-            VarDeclType.CONST -> {
-                // note that constants are all folded away, but assembly code may still refer to them (if their integers)
-                // floating point constants are not generated at all!!
-                val lv = decl.value as LiteralValue
-                if(lv.type in IntegerDatatypes)
-                    currentBlock.memoryPointers[scopedname] = Pair(lv.asIntegerValue!!, decl.datatype)
-            }
-        }
-    }
-
-    fun instr(opcode: Opcode, arg: Value? = null, arg2: Value? = null, callLabel: String? = null, callLabel2: String? = null) {
-        currentBlock.instructions.add(Instruction(opcode, arg, arg2, callLabel, callLabel2))
-    }
-
-    fun label(labelname: String, asmProc: Boolean=false) {
-        val instr = LabelInstr(labelname, asmProc)
-        currentBlock.instructions.add(instr)
-        currentBlock.labels[labelname] = instr
-    }
-
-    fun line(position: Position) {
-        currentBlock.instructions.add(Instruction(Opcode.LINE, callLabel = "${position.line} ${position.file}"))
-    }
-
-    fun removeLastInstruction() {
-        currentBlock.instructions.removeAt(currentBlock.instructions.lastIndex)
-    }
-
-    fun memoryPointer(name: String, address: Int, datatype: DataType) {
-        currentBlock.memoryPointers[name] = Pair(address, datatype)
-    }
-
-    fun newBlock(scopedname: String, shortname: String, address: Int?, options: Set<String>) {
-        currentBlock = ProgramBlock(scopedname, shortname, address, force_output="force_output" in options)
-        blocks.add(currentBlock)
-    }
-
-    fun writeCode(out: PrintStream, embeddedLabels: Boolean=true) {
-        out.println("; stackVM program code for '$name'")
-        out.println("%memory")
-        if(memory.isNotEmpty())
-            TODO("add support for writing/reading initial memory values")
-        out.println("%end_memory")
-        out.println("%heap")
-        heap.allEntries().forEach {
-            when {
-                it.value.str!=null ->
-                    out.println("${it.key}  ${it.value.type.toString().toLowerCase()}  \"${escape(it.value.str!!)}\"")
-                it.value.array!=null ->
-                    out.println("${it.key}  ${it.value.type.toString().toLowerCase()}  ${it.value.array!!.toList()}")
-                it.value.doubleArray!=null ->
-                    out.println("${it.key}  ${it.value.type.toString().toLowerCase()}  ${it.value.doubleArray!!.toList()}")
-                else -> throw CompilerException("invalid heap entry $it")
-            }
-        }
-        out.println("%end_heap")
-        for(blk in blocks) {
-            out.println("\n%block ${blk.scopedname} ${blk.address?.toString(16) ?: ""}")
-
-            out.println("%variables")
-            for(variable in blk.variables) {
-                val valuestr = variable.value.toString()
-                out.println("${variable.key}  ${variable.value.type.toString().toLowerCase()}  $valuestr")
-            }
-            out.println("%end_variables")
-            out.println("%memorypointers")
-            for(iconst in blk.memoryPointers) {
-                out.println("${iconst.key}  ${iconst.value.second.toString().toLowerCase()}  uw:${iconst.value.first.toString(16)}")
-            }
-            out.println("%end_memorypointers")
-            out.println("%instructions")
-            val labels = blk.labels.entries.associateBy({it.value}) {it.key}
-            for(instr in blk.instructions) {
-                if(!embeddedLabels) {
-                    val label = labels[instr]
-                    if (label != null)
-                        out.println("$label:")
-                } else {
-                    out.println(instr)
-                }
-            }
-            out.println("%end_instructions")
-
-            out.println("%end_block")
-        }
-    }
-}

compiler/src/prog8/compiler/intermediate/Opcode.kt

@@ -1,292 +0,0 @@
-package prog8.compiler.intermediate
-
-enum class Opcode {
-
-    // pushing values on the (evaluation) stack
-    PUSH_BYTE,       // push byte value
-    PUSH_WORD,       // push word value   (or 'address' of string / array)
-    PUSH_FLOAT,      // push float value
-    PUSH_MEM_B,      // push byte value from memory to stack
-    PUSH_MEM_UB,     // push unsigned byte value from memory to stack
-    PUSH_MEM_W,      // push word value from memory to stack
-    PUSH_MEM_UW,     // push unsigned word value from memory to stack
-    PUSH_MEM_FLOAT,  // push float value from memory to stack
-    PUSH_MEMREAD,    // push memory value from address that's on the stack
-    PUSH_VAR_BYTE,   // push byte variable (ubyte, byte)
-    PUSH_VAR_WORD,   // push word variable (uword, word)
-    PUSH_VAR_FLOAT,  // push float variable
-    PUSH_REGAX_WORD, // push registers A/X as a 16-bit word
-    PUSH_REGAY_WORD, // push registers A/Y as a 16-bit word
-    PUSH_REGXY_WORD, // push registers X/Y as a 16-bit word
-    PUSH_ADDR_HEAPVAR,  // push the address of the variable that's on the heap (string or array)
-
-    // popping values off the (evaluation) stack, possibly storing them in another location
-    DISCARD_BYTE,    // discard top byte value
-    DISCARD_WORD,    // discard top word value
-    DISCARD_FLOAT,   // discard top float value
-    POP_MEM_BYTE,    // pop (u)byte value into destination memory address
-    POP_MEM_WORD,    // pop (u)word value into destination memory address
-    POP_MEM_FLOAT,   // pop float value into destination memory address
-    POP_MEMWRITE,    // pop address and byte stack and write the byte to the memory address
-    POP_VAR_BYTE,    // pop (u)byte value into variable
-    POP_VAR_WORD,    // pop (u)word value into variable
-    POP_VAR_FLOAT,   // pop float value into variable
-    POP_REGAX_WORD,  // pop uword from stack into A/X registers
-    POP_REGAY_WORD,  // pop uword from stack into A/Y registers
-    POP_REGXY_WORD,  // pop uword from stack into X/Y registers
-
-    // numeric arithmetic
-    ADD_UB,
-    ADD_B,
-    ADD_UW,
-    ADD_W,
-    ADD_F,
-    SUB_UB,
-    SUB_B,
-    SUB_UW,
-    SUB_W,
-    SUB_F,
-    MUL_UB,
-    MUL_B,
-    MUL_UW,
-    MUL_W,
-    MUL_F,
-    IDIV_UB,
-    IDIV_B,
-    IDIV_UW,
-    IDIV_W,
-    DIV_F,
-    REMAINDER_UB,   // signed remainder is undefined/unimplemented
-    REMAINDER_UW,   // signed remainder is undefined/unimplemented
-    POW_UB,
-    POW_B,
-    POW_UW,
-    POW_W,
-    POW_F,
-    NEG_B,
-    NEG_W,
-    NEG_F,
-    ABS_B,
-    ABS_W,
-    ABS_F,
-
-    // bit shifts and bitwise arithmetic
-    SHIFTEDL_BYTE,      // shifts stack value rather than in-place mem/var
-    SHIFTEDL_WORD,      // shifts stack value rather than in-place mem/var
-    SHIFTEDR_UBYTE,     // shifts stack value rather than in-place mem/var
-    SHIFTEDR_SBYTE,     // shifts stack value rather than in-place mem/var
-    SHIFTEDR_UWORD,     // shifts stack value rather than in-place mem/var
-    SHIFTEDR_SWORD,     // shifts stack value rather than in-place mem/var
-    SHL_BYTE,
-    SHL_WORD,
-    SHL_MEM_BYTE,
-    SHL_MEM_WORD,
-    SHL_VAR_BYTE,
-    SHL_VAR_WORD,
-    SHR_UBYTE,
-    SHR_SBYTE,
-    SHR_UWORD,
-    SHR_SWORD,
-    SHR_MEM_UBYTE,
-    SHR_MEM_SBYTE,
-    SHR_MEM_UWORD,
-    SHR_MEM_SWORD,
-    SHR_VAR_UBYTE,
-    SHR_VAR_SBYTE,
-    SHR_VAR_UWORD,
-    SHR_VAR_SWORD,
-    ROL_BYTE,
-    ROL_WORD,
-    ROL_MEM_BYTE,
-    ROL_MEM_WORD,
-    ROL_VAR_BYTE,
-    ROL_VAR_WORD,
-    ROR_BYTE,
-    ROR_WORD,
-    ROR_MEM_BYTE,
-    ROR_MEM_WORD,
-    ROR_VAR_BYTE,
-    ROR_VAR_WORD,
-    ROL2_BYTE,
-    ROL2_WORD,
-    ROL2_MEM_BYTE,
-    ROL2_MEM_WORD,
-    ROL2_VAR_BYTE,
-    ROL2_VAR_WORD,
-    ROR2_BYTE,
-    ROR2_WORD,
-    ROR2_MEM_BYTE,
-    ROR2_MEM_WORD,
-    ROR2_VAR_BYTE,
-    ROR2_VAR_WORD,
-    BITAND_BYTE,
-    BITAND_WORD,
-    BITOR_BYTE,
-    BITOR_WORD,
-    BITXOR_BYTE,
-    BITXOR_WORD,
-    INV_BYTE,
-    INV_WORD,
-
-    // numeric type conversions
-    MSB,        // note: lsb is equivalent to  CAST_UW_TO_UB  or CAST_W_TO_UB
-    MKWORD,        // create a word from lsb + msb
-    CAST_UB_TO_B,
-    CAST_UB_TO_UW,
-    CAST_UB_TO_W,
-    CAST_UB_TO_F,
-    CAST_B_TO_UB,
-    CAST_B_TO_UW,
-    CAST_B_TO_W,
-    CAST_B_TO_F,
-    CAST_W_TO_UB,
-    CAST_W_TO_B,
-    CAST_W_TO_UW,
-    CAST_W_TO_F,
-    CAST_UW_TO_UB,
-    CAST_UW_TO_B,
-    CAST_UW_TO_W,
-    CAST_UW_TO_F,
-    CAST_F_TO_UB,
-    CAST_F_TO_B,
-    CAST_F_TO_UW,
-    CAST_F_TO_W,
-
-    // logical operations
-    AND_BYTE,
-    AND_WORD,
-    OR_BYTE,
-    OR_WORD,
-    XOR_BYTE,
-    XOR_WORD,
-    NOT_BYTE,
-    NOT_WORD,
-
-    // increment, decrement
-    INC_VAR_B,
-    INC_VAR_UB,
-    INC_VAR_W,
-    INC_VAR_UW,
-    INC_VAR_F,
-    DEC_VAR_B,
-    DEC_VAR_UB,
-    DEC_VAR_W,
-    DEC_VAR_UW,
-    DEC_VAR_F,
-    INC_MEMORY,             // increment direct address
-    DEC_MEMORY,             // decrement direct address
-    POP_INC_MEMORY,         // increment address from stack
-    POP_DEC_MEMORY,         // decrement address from address
-
-    // comparisons
-    LESS_B,
-    LESS_UB,
-    LESS_W,
-    LESS_UW,
-    LESS_F,
-    GREATER_B,
-    GREATER_UB,
-    GREATER_W,
-    GREATER_UW,
-    GREATER_F,
-    LESSEQ_B,
-    LESSEQ_UB,
-    LESSEQ_W,
-    LESSEQ_UW,
-    LESSEQ_F,
-    GREATEREQ_B,
-    GREATEREQ_UB,
-    GREATEREQ_W,
-    GREATEREQ_UW,
-    GREATEREQ_F,
-    EQUAL_BYTE,
-    EQUAL_WORD,
-    EQUAL_F,
-    NOTEQUAL_BYTE,
-    NOTEQUAL_WORD,
-    NOTEQUAL_F,
-    CMP_B,          // sets processor status flags based on comparison, instead of pushing a result value
-    CMP_UB,         // sets processor status flags based on comparison, instead of pushing a result value
-    CMP_W,          // sets processor status flags based on comparison, instead of pushing a result value
-    CMP_UW,         // sets processor status flags based on comparison, instead of pushing a result value
-
-    // array access and simple manipulations
-    READ_INDEXED_VAR_BYTE,
-    READ_INDEXED_VAR_WORD,
-    READ_INDEXED_VAR_FLOAT,
-    WRITE_INDEXED_VAR_BYTE,
-    WRITE_INDEXED_VAR_WORD,
-    WRITE_INDEXED_VAR_FLOAT,
-    INC_INDEXED_VAR_B,
-    INC_INDEXED_VAR_UB,
-    INC_INDEXED_VAR_W,
-    INC_INDEXED_VAR_UW,
-    INC_INDEXED_VAR_FLOAT,
-    DEC_INDEXED_VAR_B,
-    DEC_INDEXED_VAR_UB,
-    DEC_INDEXED_VAR_W,
-    DEC_INDEXED_VAR_UW,
-    DEC_INDEXED_VAR_FLOAT,
-
-    // branching, without consuming a value from the stack
-    JUMP,
-    BCS,       // branch if carry set
-    BCC,       // branch if carry clear
-    BZ,        // branch if zero flag
-    BNZ,       // branch if not zero flag
-    BNEG,      // branch if negative flag
-    BPOS,      // branch if not negative flag
-    BVS,       // branch if overflow flag
-    BVC,       // branch if not overflow flag
-    // branching, based on value on the stack (which is consumed)
-    JZ,         // branch if value is zero (byte)
-    JNZ,        // branch if value is not zero (byte)
-    JZW,         // branch if value is zero (word)
-    JNZW,        // branch if value is not zero (word)
-
-
-    // subroutines
-    CALL,
-    RETURN,
-    SYSCALL,
-    START_PROCDEF,
-    END_PROCDEF,
-
-    // misc
-    SEC,        // set carry status flag  NOTE: is mostly fake, carry flag is not affected by any numeric operations
-    CLC,        // clear carry status flag  NOTE: is mostly fake, carry flag is not affected by any numeric operations
-    SEI,        // set irq-disable status flag
-    CLI,        // clear irq-disable status flag
-    RSAVE,      // save all internal registers and status flags
-    RSAVEX,     // save just X (the evaluation stack pointer)
-    RRESTORE,   // restore all internal registers and status flags
-    RRESTOREX,  // restore just X (the evaluation stack pointer)
-
-    NOP,        // do nothing
-    BREAKPOINT, // breakpoint
-    TERMINATE,  // end the program
-    LINE,       // track source file line number
-    INLINE_ASSEMBLY         // container to hold inline raw assembly code
-}
-
-val opcodesWithVarArgument = setOf(
-        Opcode.INC_VAR_B, Opcode.INC_VAR_W, Opcode.DEC_VAR_B, Opcode.DEC_VAR_W,
-        Opcode.INC_VAR_UB, Opcode.INC_VAR_UW, Opcode.DEC_VAR_UB, Opcode.DEC_VAR_UW,
-        Opcode.SHR_VAR_SBYTE, Opcode.SHR_VAR_UBYTE, Opcode.SHR_VAR_SWORD, Opcode.SHR_VAR_UWORD,
-        Opcode.SHL_VAR_BYTE, Opcode.SHL_VAR_WORD,
-        Opcode.ROL_VAR_BYTE, Opcode.ROL_VAR_WORD, Opcode.ROR_VAR_BYTE, Opcode.ROR_VAR_WORD,
-        Opcode.ROL2_VAR_BYTE, Opcode.ROL2_VAR_WORD, Opcode.ROR2_VAR_BYTE, Opcode.ROR2_VAR_WORD,
-        Opcode.POP_VAR_BYTE, Opcode.POP_VAR_WORD, Opcode.POP_VAR_FLOAT,
-        Opcode.PUSH_VAR_BYTE, Opcode.PUSH_VAR_WORD, Opcode.PUSH_VAR_FLOAT, Opcode.PUSH_ADDR_HEAPVAR,
-        Opcode.READ_INDEXED_VAR_BYTE, Opcode.READ_INDEXED_VAR_WORD, Opcode.READ_INDEXED_VAR_FLOAT,
-        Opcode.WRITE_INDEXED_VAR_BYTE, Opcode.WRITE_INDEXED_VAR_WORD, Opcode.WRITE_INDEXED_VAR_FLOAT,
-        Opcode.INC_INDEXED_VAR_UB, Opcode.INC_INDEXED_VAR_B, Opcode.INC_INDEXED_VAR_UW,
-        Opcode.INC_INDEXED_VAR_W, Opcode.INC_INDEXED_VAR_FLOAT,
-        Opcode.DEC_INDEXED_VAR_UB, Opcode.DEC_INDEXED_VAR_B, Opcode.DEC_INDEXED_VAR_UW,
-        Opcode.DEC_INDEXED_VAR_W, Opcode.DEC_INDEXED_VAR_FLOAT
-)
-
-val branchOpcodes = setOf(
-        Opcode.BCS, Opcode.BCC, Opcode.BZ, Opcode.BNZ,
-        Opcode.BNEG, Opcode.BPOS, Opcode.BVS, Opcode.BVC
-)

compiler/src/prog8/compiler/intermediate/Value.kt

@@ -1,478 +0,0 @@
-package prog8.compiler.intermediate
-
-import prog8.ast.*
-import java.lang.Exception
-import kotlin.math.abs
-import kotlin.math.pow
-
-
-class ValueException(msg: String?) : Exception(msg)
-
-
-class Value(val type: DataType, numericvalueOrHeapId: Number) {
-    private var byteval: Short? = null
-    private var wordval: Int? = null
-    private var floatval: Double? = null
-    var heapId: Int = -1
-        private set
-    val asBooleanValue: Boolean
-
-    init {
-        when(type) {
-            DataType.UBYTE -> {
-                if(numericvalueOrHeapId.toInt() !in 0..255)
-                    throw ValueException("value out of range: $numericvalueOrHeapId")
-                byteval = numericvalueOrHeapId.toShort()
-                asBooleanValue = byteval != (0.toShort())
-            }
-            DataType.BYTE -> {
-                if(numericvalueOrHeapId.toInt() !in -128..127)
-                    throw ValueException("value out of range: $numericvalueOrHeapId")
-                byteval = numericvalueOrHeapId.toShort()
-                asBooleanValue = byteval != (0.toShort())
-            }
-            DataType.UWORD -> {
-                if(numericvalueOrHeapId.toInt() !in 0..65535)
-                    throw ValueException("value out of range: $numericvalueOrHeapId")
-                wordval = numericvalueOrHeapId.toInt()
-                asBooleanValue = wordval != 0
-            }
-            DataType.WORD -> {
-                if(numericvalueOrHeapId.toInt() !in -32768..32767)
-                    throw ValueException("value out of range: $numericvalueOrHeapId")
-                wordval = numericvalueOrHeapId.toInt()
-                asBooleanValue = wordval != 0
-            }
-            DataType.FLOAT -> {
-                floatval = numericvalueOrHeapId.toDouble()
-                asBooleanValue = floatval != 0.0
-            }
-            else -> {
-                if(numericvalueOrHeapId !is Int || numericvalueOrHeapId<0)
-                    throw ValueException("for non-numeric types, the value should be a integer heapId >= 0")
-                heapId = numericvalueOrHeapId
-                asBooleanValue=true
-            }
-        }
-    }
-
-    override fun toString(): String {
-        return when(type) {
-            DataType.UBYTE -> "ub:%02x".format(byteval)
-            DataType.BYTE -> {
-                if(byteval!!<0)
-                    "b:-%02x".format(abs(byteval!!.toInt()))
-                else
-                    "b:%02x".format(byteval)
-            }
-            DataType.UWORD -> "uw:%04x".format(wordval)
-            DataType.WORD -> {
-                if(wordval!!<0)
-                    "w:-%04x".format(abs(wordval!!))
-                else
-                    "w:%04x".format(wordval)
-            }
-            DataType.FLOAT -> "f:$floatval"
-            else -> "heap:$heapId"
-        }
-    }
-
-    fun numericValue(): Number {
-        return when(type) {
-            DataType.UBYTE, DataType.BYTE -> byteval!!
-            DataType.UWORD, DataType.WORD -> wordval!!
-            DataType.FLOAT -> floatval!!
-            else -> throw ValueException("invalid datatype for numeric value: $type")
-        }
-    }
-
-    fun integerValue(): Int {
-        return when(type) {
-            DataType.UBYTE, DataType.BYTE -> byteval!!.toInt()
-            DataType.UWORD, DataType.WORD -> wordval!!
-            DataType.FLOAT -> throw ValueException("float to integer loss of precision")
-            else -> throw ValueException("invalid datatype for integer value: $type")
-        }
-    }
-
-    override fun hashCode(): Int {
-        val bh = byteval?.hashCode() ?: 0x10001234
-        val wh = wordval?.hashCode() ?: 0x01002345
-        val fh = floatval?.hashCode() ?: 0x00103456
-        return bh xor wh xor fh xor heapId.hashCode() xor type.hashCode()
-    }
-
-    override fun equals(other: Any?): Boolean {
-        if(other==null || other !is Value)
-            return false
-        if(type==other.type)
-            return if (type in IterableDatatypes) heapId==other.heapId else compareTo(other)==0
-        return compareTo(other)==0      // note: datatype doesn't matter
-    }
-
-    operator fun compareTo(other: Value): Int {
-        return if (type in NumericDatatypes && other.type in NumericDatatypes)
-                numericValue().toDouble().compareTo(other.numericValue().toDouble())
-            else throw ValueException("comparison can only be done between two numeric values")
-    }
-
-    private fun arithResult(leftDt: DataType, result: Number, rightDt: DataType, op: String): Value {
-        if(leftDt!=rightDt)
-            throw ValueException("left and right datatypes are not the same")
-        if(result.toDouble() < 0 ) {
-            return when(leftDt) {
-                DataType.UBYTE, DataType.UWORD -> {
-                    // storing a negative number in an unsigned one is done by storing the 2's complement instead
-                    val number = abs(result.toDouble().toInt())
-                    if(leftDt==DataType.UBYTE)
-                        Value(DataType.UBYTE, (number xor 255) + 1)
-                    else
-                        Value(DataType.UBYTE, (number xor 65535) + 1)
-                }
-                DataType.BYTE -> Value(DataType.BYTE, result.toInt())
-                DataType.WORD -> Value(DataType.WORD, result.toInt())
-                DataType.FLOAT -> Value(DataType.FLOAT, result)
-                else -> throw ValueException("$op on non-numeric type")
-            }
-        }
-
-        return when(leftDt) {
-            DataType.UBYTE -> Value(DataType.UBYTE, result.toInt() and 255)
-            DataType.BYTE -> Value(DataType.BYTE, result.toInt())
-            DataType.UWORD -> Value(DataType.UWORD, result.toInt() and 65535)
-            DataType.WORD -> Value(DataType.WORD, result.toInt())
-            DataType.FLOAT -> Value(DataType.FLOAT, result)
-            else -> throw ValueException("$op on non-numeric type")
-        }
-    }
-
-    fun add(other: Value): Value {
-        if(other.type == DataType.FLOAT && (type!= DataType.FLOAT))
-            throw ValueException("floating point loss of precision on type $type")
-        val v1 = numericValue()
-        val v2 = other.numericValue()
-        val result = v1.toDouble() + v2.toDouble()
-        return arithResult(type, result, other.type, "add")
-    }
-
-    fun sub(other: Value): Value {
-        if(other.type == DataType.FLOAT && (type!= DataType.FLOAT))
-            throw ValueException("floating point loss of precision on type $type")
-        val v1 = numericValue()
-        val v2 = other.numericValue()
-        val result = v1.toDouble() - v2.toDouble()
-        return arithResult(type, result, other.type, "sub")
-    }
-
-    fun mul(other: Value): Value {
-        if(other.type == DataType.FLOAT && (type!= DataType.FLOAT))
-            throw ValueException("floating point loss of precision on type $type")
-        val v1 = numericValue()
-        val v2 = other.numericValue()
-        val result = v1.toDouble() * v2.toDouble()
-        return arithResult(type, result, other.type, "mul")
-    }
-
-    fun div(other: Value): Value {
-        if(other.type == DataType.FLOAT && (type!= DataType.FLOAT))
-            throw ValueException("floating point loss of precision on type $type")
-        val v1 = numericValue()
-        val v2 = other.numericValue()
-        if(v2.toDouble()==0.0) {
-            when (type) {
-                DataType.UBYTE -> return Value(DataType.UBYTE, 255)
-                DataType.BYTE -> return Value(DataType.BYTE, 127)
-                DataType.UWORD -> return Value(DataType.UWORD, 65535)
-                DataType.WORD -> return Value(DataType.WORD, 32767)
-                else -> {}
-            }
-        }
-        val result = v1.toDouble() / v2.toDouble()
-        // NOTE: integer division returns integer result!
-        return when(type) {
-            DataType.UBYTE -> Value(DataType.UBYTE, result)
-            DataType.BYTE -> Value(DataType.BYTE, result)
-            DataType.UWORD -> Value(DataType.UWORD, result)
-            DataType.WORD -> Value(DataType.WORD, result)
-            DataType.FLOAT -> Value(DataType.FLOAT, result)
-            else -> throw ValueException("div on non-numeric type")
-        }
-    }
-
-    fun remainder(other: Value): Value? {
-        val v1 = numericValue()
-        val v2 = other.numericValue()
-        val result = v1.toDouble() % v2.toDouble()
-        return arithResult(type, result, other.type, "remainder")
-    }
-
-    fun pow(other: Value): Value {
-        val v1 = numericValue()
-        val v2 = other.numericValue()
-        val result = v1.toDouble().pow(v2.toDouble())
-        return arithResult(type, result, other.type,"pow")
-    }
-
-    fun shl(): Value {
-        val v = integerValue()
-        return when (type) {
-            DataType.UBYTE -> return Value(type, (v shl 1) and 255)
-            DataType.BYTE -> {
-                if(v<0)
-                    Value(type, -((-v shl 1) and 255))
-                else
-                    Value(type, (v shl 1) and 255)
-            }
-            DataType.UWORD -> return Value(type, (v shl 1) and 65535)
-            DataType.WORD -> {
-                if(v<0)
-                    Value(type, -((-v shl 1) and 65535))
-                else
-                    Value(type, (v shl 1) and 65535)
-            }
-            else -> throw ValueException("invalid type for shl: $type")
-        }
-    }
-
-    fun shr(): Value {
-        val v = integerValue()
-        return when(type){
-            DataType.UBYTE -> Value(type, (v ushr 1) and 255)
-            DataType.BYTE -> Value(type, v shr 1)
-            DataType.UWORD -> Value(type, (v ushr 1) and 65535)
-            DataType.WORD -> Value(type, v shr 1)
-            else -> throw ValueException("invalid type for shr: $type")
-        }
-    }
-
-    fun rol(carry: Boolean): Pair<Value, Boolean> {
-        // 9 or 17 bit rotate left (with carry))
-        return when(type) {
-            DataType.UBYTE -> {
-                val v = byteval!!.toInt()
-                val newCarry = (v and 0x80) != 0
-                val newval = (v and 0x7f shl 1) or (if(carry) 1 else 0)
-                Pair(Value(DataType.UBYTE, newval), newCarry)
-            }
-            DataType.UWORD -> {
-                val v = wordval!!
-                val newCarry = (v and 0x8000) != 0
-                val newval = (v and 0x7fff shl 1) or (if(carry) 1 else 0)
-                Pair(Value(DataType.UWORD, newval), newCarry)
-            }
-            else -> throw ValueException("rol can only work on byte/word")
-        }
-    }
-
-    fun ror(carry: Boolean): Pair<Value, Boolean> {
-        // 9 or 17 bit rotate right (with carry)
-        return when(type) {
-            DataType.UBYTE -> {
-                val v = byteval!!.toInt()
-                val newCarry = v and 1 != 0
-                val newval = (v ushr 1) or (if(carry) 0x80 else 0)
-                Pair(Value(DataType.UBYTE, newval), newCarry)
-            }
-            DataType.UWORD -> {
-                val v = wordval!!
-                val newCarry = v and 1 != 0
-                val newval = (v ushr 1) or (if(carry) 0x8000 else 0)
-                Pair(Value(DataType.UWORD, newval), newCarry)
-            }
-            else -> throw ValueException("ror2 can only work on byte/word")
-        }
-    }
-
-    fun rol2(): Value {
-        // 8 or 16 bit rotate left
-        return when(type) {
-            DataType.UBYTE -> {
-                val v = byteval!!.toInt()
-                val carry = (v and 0x80) ushr 7
-                val newval = (v and 0x7f shl 1) or carry
-                Value(DataType.UBYTE, newval)
-            }
-            DataType.UWORD -> {
-                val v = wordval!!
-                val carry = (v and 0x8000) ushr 15
-                val newval = (v and 0x7fff shl 1) or carry
-                Value(DataType.UWORD, newval)
-            }
-            else -> throw ValueException("rol2 can only work on byte/word")
-        }
-    }
-
-    fun ror2(): Value {
-        // 8 or 16 bit rotate right
-        return when(type) {
-            DataType.UBYTE -> {
-                val v = byteval!!.toInt()
-                val carry = v and 1 shl 7
-                val newval = (v ushr 1) or carry
-                Value(DataType.UBYTE, newval)
-            }
-            DataType.UWORD -> {
-                val v = wordval!!
-                val carry = v and 1 shl 15
-                val newval = (v ushr 1) or carry
-                Value(DataType.UWORD, newval)
-            }
-            else -> throw ValueException("ror2 can only work on byte/word")
-        }
-    }
-
-    fun neg(): Value {
-        return when(type) {
-            DataType.BYTE -> Value(DataType.BYTE, -(byteval!!))
-            DataType.WORD -> Value(DataType.WORD, -(wordval!!))
-            DataType.FLOAT -> Value(DataType.FLOAT, -(floatval)!!)
-            else -> throw ValueException("neg can only work on byte/word/float")
-        }
-    }
-
-    fun abs(): Value {
-        return when(type) {
-            DataType.BYTE -> Value(DataType.BYTE, abs(byteval!!.toInt()))
-            DataType.WORD -> Value(DataType.WORD, abs(wordval!!))
-            DataType.FLOAT -> Value(DataType.FLOAT, abs(floatval!!))
-            else -> throw ValueException("abs can only work on byte/word/float")
-        }
-    }
-
-    fun bitand(other: Value): Value {
-        val v1 = integerValue()
-        val v2 = other.integerValue()
-        val result = v1 and v2
-        return Value(type, result)
-    }
-
-    fun bitor(other: Value): Value {
-        val v1 = integerValue()
-        val v2 = other.integerValue()
-        val result = v1 or v2
-        return Value(type, result)
-    }
-
-    fun bitxor(other: Value): Value {
-        val v1 = integerValue()
-        val v2 = other.integerValue()
-        val result = v1 xor v2
-        return Value(type, result)
-    }
-
-    fun and(other: Value) = Value(DataType.UBYTE, if (this.asBooleanValue && other.asBooleanValue) 1 else 0)
-    fun or(other: Value) = Value(DataType.UBYTE, if (this.asBooleanValue || other.asBooleanValue) 1 else 0)
-    fun xor(other: Value) = Value(DataType.UBYTE, if (this.asBooleanValue xor other.asBooleanValue) 1 else 0)
-    fun not() = Value(DataType.UBYTE, if (this.asBooleanValue) 0 else 1)
-
-    fun inv(): Value {
-        return when(type) {
-            DataType.UBYTE -> Value(DataType.UBYTE, byteval!!.toInt().inv() and 255)
-            DataType.UWORD -> Value(DataType.UWORD, wordval!!.inv() and 65535)
-            else -> throw ValueException("inv can only work on byte/word")
-        }
-    }
-
-    fun inc(): Value {
-        return when(type) {
-            DataType.UBYTE -> Value(DataType.UBYTE, (byteval!! + 1) and 255)
-            DataType.UWORD -> Value(DataType.UWORD, (wordval!! + 1) and 65535)
-            DataType.FLOAT -> Value(DataType.FLOAT, floatval!! + 1)
-            else -> throw ValueException("inc can only work on byte/word/float")
-        }
-    }
-
-    fun dec(): Value {
-        return when(type) {
-            DataType.UBYTE -> Value(DataType.UBYTE, (byteval!! - 1) and 255)
-            DataType.UWORD -> Value(DataType.UWORD, (wordval!! - 1) and 65535)
-            DataType.FLOAT -> Value(DataType.FLOAT, floatval!! - 1)
-            else -> throw ValueException("dec can only work on byte/word/float")
-        }
-    }
-
-    fun msb(): Value {
-        return when(type) {
-            DataType.UBYTE, DataType.BYTE -> Value(DataType.UBYTE, 0)
-            DataType.UWORD, DataType.WORD -> Value(DataType.UBYTE, wordval!! ushr 8 and 255)
-            else -> throw ValueException("msb can only work on (u)byte/(u)word")
-        }
-    }
-
-    fun cast(targetType: DataType): Value {
-        return when (type) {
-            DataType.UBYTE -> {
-                when (targetType) {
-                    DataType.UBYTE -> this
-                    DataType.BYTE -> {
-                        if(byteval!!<=127)
-                            Value(DataType.BYTE, byteval!!)
-                        else
-                            Value(DataType.BYTE, -(256-byteval!!))
-                    }
-                    DataType.UWORD -> Value(DataType.UWORD, numericValue())
-                    DataType.WORD -> Value(DataType.WORD, numericValue())
-                    DataType.FLOAT -> Value(DataType.FLOAT, numericValue())
-                    else -> throw ValueException("invalid type cast from $type to $targetType")
-                }
-            }
-            DataType.BYTE -> {
-                when (targetType) {
-                    DataType.BYTE -> this
-                    DataType.UBYTE -> Value(DataType.UBYTE, integerValue() and 255)
-                    DataType.UWORD -> Value(DataType.UWORD, integerValue() and 65535)
-                    DataType.WORD -> Value(DataType.WORD, integerValue())
-                    DataType.FLOAT -> Value(DataType.FLOAT, numericValue())
-                    else -> throw ValueException("invalid type cast from $type to $targetType")
-                }
-            }
-            DataType.UWORD -> {
-                when (targetType) {
-                    DataType.BYTE, DataType.UBYTE -> Value(DataType.UBYTE, integerValue() and 255)
-                    DataType.UWORD -> this
-                    DataType.WORD -> {
-                        if(integerValue()<=32767)
-                            Value(DataType.WORD, integerValue())
-                        else
-                            Value(DataType.WORD, -(65536-integerValue()))
-                    }
-                    DataType.FLOAT -> Value(DataType.FLOAT, numericValue())
-                    else -> throw ValueException("invalid type cast from $type to $targetType")
-                }
-            }
-            DataType.WORD -> {
-                when (targetType) {
-                    DataType.BYTE, DataType.UBYTE -> Value(DataType.UBYTE, integerValue() and 255)
-                    DataType.UWORD -> Value(DataType.UWORD, integerValue() and 65535)
-                    DataType.WORD -> this
-                    DataType.FLOAT -> Value(DataType.FLOAT, numericValue())
-                    else -> throw ValueException("invalid type cast from $type to $targetType")
-                }
-            }
-            DataType.FLOAT -> {
-                when (targetType) {
-                    DataType.BYTE -> {
-                        val integer=numericValue().toInt()
-                        if(integer in -128..127)
-                            Value(DataType.BYTE, integer)
-                        else
-                            throw ValueException("overflow when casting float to byte: $this")
-                    }
-                    DataType.UBYTE -> Value(DataType.UBYTE, numericValue().toInt() and 255)
-                    DataType.UWORD -> Value(DataType.UWORD, numericValue().toInt() and 65535)
-                    DataType.WORD -> {
-                        val integer=numericValue().toInt()
-                        if(integer in -32768..32767)
-                            Value(DataType.WORD, integer)
-                        else
-                            throw ValueException("overflow when casting float to word: $this")
-                    }
-                    DataType.FLOAT -> this
-                    else -> throw ValueException("invalid type cast from $type to $targetType")
-                }
-            }
-            else -> throw ValueException("invalid type cast from $type to $targetType")
-        }
-    }
-
-}

compiler/src/prog8/compiler/target/CompilationTarget.kt

@@ -0,0 +1,18 @@
+package prog8.compiler.target
+
+import prog8.ast.Program
+import prog8.ast.base.ErrorReporter
+import prog8.compiler.CompilationOptions
+import prog8.compiler.Zeropage
+import java.nio.file.Path
+
+
+internal interface CompilationTarget {
+    companion object {
+        lateinit var name: String
+        lateinit var machine: IMachineDefinition
+        lateinit var encodeString: (str: String, altEncoding: Boolean) -> List<Short>
+        lateinit var decodeString: (bytes: List<Short>, altEncoding: Boolean) -> String
+        lateinit var asmGenerator: (Program, ErrorReporter, Zeropage, CompilationOptions, Path) -> IAssemblyGenerator
+    }
+}

compiler/src/prog8/compiler/target/IAssemblyGenerator.kt

@@ -0,0 +1,14 @@
+package prog8.compiler.target
+
+import prog8.compiler.CompilationOptions
+
+internal interface IAssemblyGenerator {
+    fun compileToAssembly(optimize: Boolean): IAssemblyProgram
+}
+
+internal const val generatedLabelPrefix = "_prog8_label_"
+
+internal interface IAssemblyProgram {
+    val name: String
+    fun assemble(options: CompilationOptions)
+}

compiler/src/prog8/compiler/target/IMachineDefinition.kt

@@ -0,0 +1,34 @@
+package prog8.compiler.target
+
+import prog8.ast.Program
+import prog8.compiler.CompilationOptions
+import prog8.compiler.Zeropage
+import prog8.parser.ModuleImporter
+
+
+internal interface IMachineFloat {
+    fun toDouble(): Double
+    fun makeFloatFillAsm(): String
+}
+
+internal interface IMachineDefinition {
+    val FLOAT_MAX_NEGATIVE: Double
+    val FLOAT_MAX_POSITIVE: Double
+    val FLOAT_MEM_SIZE: Int
+    val POINTER_MEM_SIZE: Int
+    val ESTACK_LO: Int
+    val ESTACK_HI: Int
+    val BASIC_LOAD_ADDRESS : Int
+    val RAW_LOAD_ADDRESS : Int
+
+    val opcodeNames: Set<String>
+    var zeropage: Zeropage
+    val initSystemProcname: String
+    val cpu: String
+
+    fun initializeZeropage(compilerOptions: CompilationOptions)
+    fun getFloat(num: Number): IMachineFloat
+    fun getFloatRomConst(number: Double): String?
+    fun importLibs(compilerOptions: CompilationOptions, importer: ModuleImporter, program: Program)
+    fun launchEmulator(programName: String)
+}

compiler/src/prog8/compiler/target/c64/AssemblyProgram.kt

@@ -2,55 +2,72 @@ package prog8.compiler.target.c64
 
 import prog8.compiler.CompilationOptions
 import prog8.compiler.OutputType
-import java.io.File
+import prog8.compiler.target.IAssemblyProgram
+import prog8.compiler.target.generatedLabelPrefix
+import java.nio.file.Path
 import kotlin.system.exitProcess
 
-class AssemblyProgram(val name: String) {
+class AssemblyProgram(override val name: String, outputDir: Path) : IAssemblyProgram {
-    private val assemblyFile = "$name.asm"
+    private val assemblyFile = outputDir.resolve("$name.asm")
-    private val viceMonListFile = "$name.vice-mon-list"
+    private val prgFile = outputDir.resolve("$name.prg")
+    private val binFile = outputDir.resolve("$name.bin")
+    private val viceMonListFile = outputDir.resolve("$name.vice-mon-list")
 
-    fun assemble(options: CompilationOptions) {
+    override fun assemble(options: CompilationOptions) {
-        // add "-Wlong-branch"  to see warnings about conversion of branch instructions to jumps
+        // add "-Wlong-branch"  to see warnings about conversion of branch instructions to jumps (default = do this silently)
-        val command = mutableListOf("64tass", "--ascii", "--case-sensitive", "--long-branch", "-Wall", "-Wno-strict-bool",
+        val command = mutableListOf("64tass", "--ascii", "--case-sensitive", "--long-branch",
-                "-Werror", "-Wno-error=long-branch", "--dump-labels", "--vice-labels", "-l", viceMonListFile, "--no-monitor")
+                "-Wall", "-Wno-strict-bool", "-Wno-shadow", // "-Werror",
+                "--dump-labels", "--vice-labels", "-l", viceMonListFile.toString(), "--no-monitor")
 
-        val outFile = when(options.output) {
+        val outFile = when (options.output) {
             OutputType.PRG -> {
                 command.add("--cbm-prg")
-                println("\nCreating C-64 prg.")
+                println("\nCreating prg.")
-                "$name.prg"
+                prgFile
             }
             OutputType.RAW -> {
                 command.add("--nostart")
                 println("\nCreating raw binary.")
-                "$name.bin"
+                binFile
             }
         }
-        command.addAll(listOf("--output", outFile, assemblyFile))
+        command.addAll(listOf("--output", outFile.toString(), assemblyFile.toString()))
 
         val proc = ProcessBuilder(command).inheritIO().start()
         val result = proc.waitFor()
-        if(result!=0) {
+        if (result != 0) {
             System.err.println("assembler failed with returncode $result")
             exitProcess(result)
         }
 
+        removeGeneratedLabelsFromMonlist()
         generateBreakpointList()
     }
 
+    private fun removeGeneratedLabelsFromMonlist() {
+        val pattern = Regex("""al (\w+) \S+${generatedLabelPrefix}.+?""")
+        val lines = viceMonListFile.toFile().readLines()
+        viceMonListFile.toFile().outputStream().bufferedWriter().use {
+            for (line in lines) {
+                if(pattern.matchEntire(line)==null)
+                    it.write(line+"\n")
+            }
+        }
+    }
+
     private fun generateBreakpointList() {
         // builds list of breakpoints, appends to monitor list file
         val breakpoints = mutableListOf<String>()
         val pattern = Regex("""al (\w+) \S+_prog8_breakpoint_\d+.?""")      // gather breakpoints by the source label that's generated for them
-        for(line in File(viceMonListFile).readLines()) {
+        for (line in viceMonListFile.toFile().readLines()) {
             val match = pattern.matchEntire(line)
-            if(match!=null)
+            if (match != null)
-            breakpoints.add("break \$" + match.groupValues[1])
+                breakpoints.add("break \$" + match.groupValues[1])
         }
         val num = breakpoints.size
         breakpoints.add(0, "; vice monitor breakpoint list now follows")
         breakpoints.add(1, "; $num breakpoints have been defined")
         breakpoints.add(2, "del")
-        File(viceMonListFile).appendText(breakpoints.joinToString("\n")+"\n")
+        viceMonListFile.toFile().appendText(breakpoints.joinToString("\n") + "\n")
     }
 }

compiler/src/prog8/compiler/target/c64/C64MachineDefinition.kt

@@ -0,0 +1,246 @@
+package prog8.compiler.target.c64
+
+import prog8.ast.Program
+import prog8.compiler.*
+import prog8.compiler.target.IMachineDefinition
+import prog8.compiler.target.IMachineFloat
+import prog8.parser.ModuleImporter
+import java.io.IOException
+import java.math.RoundingMode
+import kotlin.math.absoluteValue
+import kotlin.math.pow
+
+internal object C64MachineDefinition: IMachineDefinition {
+
+    override val cpu = "6502"
+
+    // 5-byte cbm MFLPT format limitations:
+    override val FLOAT_MAX_POSITIVE = 1.7014118345e+38         // bytes: 255,127,255,255,255
+    override val FLOAT_MAX_NEGATIVE = -1.7014118345e+38        // bytes: 255,255,255,255,255
+    override val FLOAT_MEM_SIZE = 5
+    override val POINTER_MEM_SIZE = 2
+    override val BASIC_LOAD_ADDRESS = 0x0801
+    override val RAW_LOAD_ADDRESS = 0xc000
+
+    // the 2*256 byte evaluation stack (on which bytes, words, and even floats are stored during calculations)
+    // and some heavily used string constants derived from the two values above
+    override val ESTACK_LO = 0xce00        //  $ce00-$ceff inclusive
+    override val ESTACK_HI = 0xcf00        //  $ce00-$ceff inclusive
+
+    override lateinit var zeropage: Zeropage
+    override val initSystemProcname = "c64.init_system"
+
+    override fun getFloat(num: Number) = Mflpt5.fromNumber(num)
+
+    override fun getFloatRomConst(number: Double): String? {
+        // try to match the ROM float constants to save memory
+        val mflpt5 = Mflpt5.fromNumber(number)
+        val floatbytes = shortArrayOf(mflpt5.b0, mflpt5.b1, mflpt5.b2, mflpt5.b3, mflpt5.b4)
+        when {
+            floatbytes.contentEquals(shortArrayOf(0x00, 0x00, 0x00, 0x00, 0x00)) -> return "c64flt.FL_ZERO"
+            floatbytes.contentEquals(shortArrayOf(0x82, 0x49, 0x0f, 0xda, 0xa1)) -> return "c64flt.FL_PIVAL"
+            floatbytes.contentEquals(shortArrayOf(0x90, 0x80, 0x00, 0x00, 0x00)) -> return "c64flt.FL_N32768"
+            floatbytes.contentEquals(shortArrayOf(0x81, 0x00, 0x00, 0x00, 0x00)) -> return "c64flt.FL_FONE"
+            floatbytes.contentEquals(shortArrayOf(0x80, 0x35, 0x04, 0xf3, 0x34)) -> return "c64flt.FL_SQRHLF"
+            floatbytes.contentEquals(shortArrayOf(0x81, 0x35, 0x04, 0xf3, 0x34)) -> return "c64flt.FL_SQRTWO"
+            floatbytes.contentEquals(shortArrayOf(0x80, 0x80, 0x00, 0x00, 0x00)) -> return "c64flt.FL_NEGHLF"
+            floatbytes.contentEquals(shortArrayOf(0x80, 0x31, 0x72, 0x17, 0xf8)) -> return "c64flt.FL_LOG2"
+            floatbytes.contentEquals(shortArrayOf(0x84, 0x20, 0x00, 0x00, 0x00)) -> return "c64flt.FL_TENC"
+            floatbytes.contentEquals(shortArrayOf(0x9e, 0x6e, 0x6b, 0x28, 0x00)) -> return "c64flt.FL_NZMIL"
+            floatbytes.contentEquals(shortArrayOf(0x80, 0x00, 0x00, 0x00, 0x00)) -> return "c64flt.FL_FHALF"
+            floatbytes.contentEquals(shortArrayOf(0x81, 0x38, 0xaa, 0x3b, 0x29)) -> return "c64flt.FL_LOGEB2"
+            floatbytes.contentEquals(shortArrayOf(0x81, 0x49, 0x0f, 0xda, 0xa2)) -> return "c64flt.FL_PIHALF"
+            floatbytes.contentEquals(shortArrayOf(0x83, 0x49, 0x0f, 0xda, 0xa2)) -> return "c64flt.FL_TWOPI"
+            floatbytes.contentEquals(shortArrayOf(0x7f, 0x00, 0x00, 0x00, 0x00)) -> return "c64flt.FL_FR4"
+            else -> {
+                // attempt to correct for a few rounding issues
+                when (number.toBigDecimal().setScale(10, RoundingMode.HALF_DOWN).toDouble()) {
+                    3.1415926536 -> return "c64flt.FL_PIVAL"
+                    1.4142135624 -> return "c64flt.FL_SQRTWO"
+                    0.7071067812 -> return "c64flt.FL_SQRHLF"
+                    0.6931471806 -> return "c64flt.FL_LOG2"
+                    else -> {}
+                }
+            }
+        }
+        return null
+    }
+
+    override fun importLibs(compilerOptions: CompilationOptions, importer: ModuleImporter, program: Program) {
+        if (compilerOptions.launcher == LauncherType.BASIC || compilerOptions.output == OutputType.PRG)
+            importer.importLibraryModule(program, "c64lib")
+    }
+
+    override fun launchEmulator(programName: String) {
+        for(emulator in listOf("x64sc", "x64")) {
+            println("\nStarting C-64 emulator $emulator...")
+            val cmdline = listOf(emulator, "-silent", "-moncommands", "$programName.vice-mon-list",
+                    "-autostartprgmode", "1", "-autostart-warp", "-autostart", programName + ".prg")
+            val processb = ProcessBuilder(cmdline).inheritIO()
+            val process: Process
+            try {
+                process=processb.start()
+            } catch(x: IOException) {
+                continue  // try the next emulator executable
+            }
+            process.waitFor()
+            break
+        }
+    }
+
+    override fun initializeZeropage(compilerOptions: CompilationOptions) {
+        zeropage = C64Zeropage(compilerOptions)
+    }
+
+    // 6502 opcodes (including aliases and illegal opcodes), these cannot be used as variable or label names
+    override val opcodeNames = setOf("adc", "ahx", "alr", "anc", "and", "ane", "arr", "asl", "asr", "axs", "bcc", "bcs",
+            "beq", "bge", "bit", "blt", "bmi", "bne", "bpl", "brk", "bvc", "bvs", "clc",
+            "cld", "cli", "clv", "cmp", "cpx", "cpy", "dcm", "dcp", "dec", "dex", "dey",
+            "eor", "gcc", "gcs", "geq", "gge", "glt", "gmi", "gne", "gpl", "gvc", "gvs",
+            "inc", "ins", "inx", "iny", "isb", "isc", "jam", "jmp", "jsr", "lae", "las",
+            "lax", "lda", "lds", "ldx", "ldy", "lsr", "lxa", "nop", "ora", "pha", "php",
+            "pla", "plp", "rla", "rol", "ror", "rra", "rti", "rts", "sax", "sbc", "sbx",
+            "sec", "sed", "sei", "sha", "shl", "shr", "shs", "shx", "shy", "slo", "sre",
+            "sta", "stx", "sty", "tas", "tax", "tay", "tsx", "txa", "txs", "tya", "xaa")
+
+
+    internal class C64Zeropage(options: CompilationOptions) : Zeropage(options) {
+
+        override val SCRATCH_B1 = 0x02      // temp storage for a single byte
+        override val SCRATCH_REG = 0x03     // temp storage for a register
+        override val SCRATCH_REG_X = 0xfa   // temp storage for register X (the evaluation stack pointer)
+        override val SCRATCH_W1 = 0xfb      // temp storage 1 for a word  $fb+$fc
+        override val SCRATCH_W2 = 0xfd      // temp storage 2 for a word  $fb+$fc
+
+
+        override val exitProgramStrategy: ExitProgramStrategy = when (options.zeropage) {
+            ZeropageType.BASICSAFE, ZeropageType.DONTUSE -> ExitProgramStrategy.CLEAN_EXIT
+            ZeropageType.FLOATSAFE, ZeropageType.KERNALSAFE, ZeropageType.FULL -> ExitProgramStrategy.SYSTEM_RESET
+        }
+
+
+        init {
+            if (options.floats && options.zeropage !in setOf(ZeropageType.FLOATSAFE, ZeropageType.BASICSAFE, ZeropageType.DONTUSE ))
+                throw CompilerException("when floats are enabled, zero page type should be 'floatsafe' or 'basicsafe' or 'dontuse'")
+
+            if (options.zeropage == ZeropageType.FULL) {
+                free.addAll(0x04..0xf9)
+                free.add(0xff)
+                free.removeAll(listOf(SCRATCH_B1, SCRATCH_REG, SCRATCH_REG_X, SCRATCH_W1, SCRATCH_W1 + 1, SCRATCH_W2, SCRATCH_W2 + 1))
+                free.removeAll(listOf(0xa0, 0xa1, 0xa2, 0x91, 0xc0, 0xc5, 0xcb, 0xf5, 0xf6))        // these are updated by IRQ
+            } else {
+                if (options.zeropage == ZeropageType.KERNALSAFE || options.zeropage == ZeropageType.FLOATSAFE) {
+                    free.addAll(listOf(0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10, 0x11,
+                            0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, 0x20, 0x21,
+                            0x22, 0x23, 0x24, 0x25,
+                            0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f, 0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46,
+                            0x47, 0x48, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f, 0x51, 0x52, 0x53,
+                            0x57, 0x58, 0x59, 0x5a, 0x5b, 0x5c, 0x5d, 0x5e, 0x5f, 0x60,
+                            0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68,
+                            0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f, 0x70, 0x71, 0x72,
+                            0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7a, 0x7b, 0x7c,
+                            0x7d, 0x7e, 0x7f, 0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89, 0x8a,
+                            0x8b, 0x8c, 0x8d, 0x8e, 0x8f, 0xff
+                            // 0x90-0xfa is 'kernel work storage area'
+                    ))
+                }
+
+                if (options.zeropage == ZeropageType.FLOATSAFE) {
+                    // remove the zero page locations used for floating point operations from the free list
+                    free.removeAll(listOf(
+                            0x12, 0x26, 0x27, 0x28, 0x29, 0x2a,
+                            0x57, 0x58, 0x59, 0x5a, 0x5b, 0x5c, 0x5d, 0x5e, 0x5f, 0x60,
+                            0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68,
+                            0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f, 0x70, 0x71, 0x72,
+                            0x8b, 0x8c, 0x8d, 0x8e, 0x8f, 0xf
+                    ))
+                }
+
+                if(options.zeropage!=ZeropageType.DONTUSE) {
+                    // add the other free Zp addresses,
+                    // these are valid for the C-64 (when no RS232 I/O is performed) but to keep BASIC running fully:
+                    free.addAll(listOf(0x04, 0x05, 0x06, 0x0a, 0x0e,
+                            0x94, 0x95, 0xa7, 0xa8, 0xa9, 0xaa,
+                            0xb5, 0xb6, 0xf7, 0xf8, 0xf9))
+                } else {
+                    // don't use the zeropage at all
+                    free.clear()
+                }
+            }
+            require(SCRATCH_B1 !in free)
+            require(SCRATCH_REG !in free)
+            require(SCRATCH_REG_X !in free)
+            require(SCRATCH_W1 !in free)
+            require(SCRATCH_W2 !in free)
+
+            for (reserved in options.zpReserved)
+                reserve(reserved)
+        }
+    }
+
+    internal data class Mflpt5(val b0: Short, val b1: Short, val b2: Short, val b3: Short, val b4: Short): IMachineFloat {
+
+        companion object {
+            val zero = Mflpt5(0, 0, 0, 0, 0)
+            fun fromNumber(num: Number): Mflpt5 {
+                // see https://en.wikipedia.org/wiki/Microsoft_Binary_Format
+                // and https://sourceforge.net/p/acme-crossass/code-0/62/tree/trunk/ACME_Lib/cbm/mflpt.a
+                // and https://en.wikipedia.org/wiki/IEEE_754-1985
+
+                val flt = num.toDouble()
+                if (flt < FLOAT_MAX_NEGATIVE || flt > FLOAT_MAX_POSITIVE)
+                    throw CompilerException("floating point number out of 5-byte mflpt range: $this")
+                if (flt == 0.0)
+                    return zero
+
+                val sign = if (flt < 0.0) 0x80L else 0x00L
+                var exponent = 128 + 32    // 128 is cbm's bias, 32 is this algo's bias
+                var mantissa = flt.absoluteValue
+
+                // if mantissa is too large, shift right and adjust exponent
+                while (mantissa >= 0x100000000) {
+                    mantissa /= 2.0
+                    exponent++
+                }
+                // if mantissa is too small, shift left and adjust exponent
+                while (mantissa < 0x80000000) {
+                    mantissa *= 2.0
+                    exponent--
+                }
+
+                return when {
+                    exponent < 0 -> zero  // underflow, use zero instead
+                    exponent > 255 -> throw CompilerException("floating point overflow: $this")
+                    exponent == 0 -> zero
+                    else -> {
+                        val mantLong = mantissa.toLong()
+                        Mflpt5(
+                                exponent.toShort(),
+                                (mantLong.and(0x7f000000L) ushr 24).or(sign).toShort(),
+                                (mantLong.and(0x00ff0000L) ushr 16).toShort(),
+                                (mantLong.and(0x0000ff00L) ushr 8).toShort(),
+                                (mantLong.and(0x000000ffL)).toShort())
+                    }
+                }
+            }
+        }
+
+        override fun toDouble(): Double {
+            if (this == zero) return 0.0
+            val exp = b0 - 128
+            val sign = (b1.toInt() and 0x80) > 0
+            val number = 0x80000000L.or(b1.toLong() shl 24).or(b2.toLong() shl 16).or(b3.toLong() shl 8).or(b4.toLong())
+            val result = number.toDouble() * (2.0).pow(exp) / 0x100000000
+            return if (sign) -result else result
+        }
+
+        override fun makeFloatFillAsm(): String {
+            val b0 = "$" + b0.toString(16).padStart(2, '0')
+            val b1 = "$" + b1.toString(16).padStart(2, '0')
+            val b2 = "$" + b2.toString(16).padStart(2, '0')
+            val b3 = "$" + b3.toString(16).padStart(2, '0')
+            val b4 = "$" + b4.toString(16).padStart(2, '0')
+            return "$b0, $b1, $b2, $b3, $b4"
+        }
+    }
+}

compiler/src/prog8/compiler/target/c64/Commodore64.kt

@@ -1,157 +0,0 @@
-package prog8.compiler.target.c64
-
-import prog8.compiler.CompilationOptions
-import prog8.compiler.CompilerException
-import prog8.compiler.Zeropage
-import prog8.compiler.ZeropageType
-import java.awt.Color
-import java.awt.image.BufferedImage
-import javax.imageio.ImageIO
-import kotlin.math.absoluteValue
-import kotlin.math.pow
-
-
-// 5-byte cbm MFLPT format limitations:
-const val FLOAT_MAX_POSITIVE = 1.7014118345e+38         // bytes: 255,127,255,255,255
-const val FLOAT_MAX_NEGATIVE = -1.7014118345e+38        // bytes: 255,255,255,255,255
-
-const val BASIC_LOAD_ADDRESS = 0x0801
-const val RAW_LOAD_ADDRESS = 0xc000
-
-// the 2*256 byte evaluation stack (on which bytes, words, and even floats are stored during calculations)
-const val ESTACK_LO = 0xce00        //  $ce00-$ceff inclusive
-const val ESTACK_HI = 0xcf00        //  $cf00-$cfff inclusive
-
-
-class C64Zeropage(options: CompilationOptions) : Zeropage(options) {
-
-    companion object {
-        const val SCRATCH_B1 = 0x02
-        const val SCRATCH_REG = 0x03    // temp storage for a register
-        const val SCRATCH_REG_X = 0xfa    // temp storage for register X (the evaluation stack pointer)
-        const val SCRATCH_W1 = 0xfb     // $fb/$fc
-        const val SCRATCH_W2 = 0xfd     // $fd/$fe
-    }
-
-    init {
-        if(options.zeropage== ZeropageType.FULL) {
-            free.addAll(0x04 .. 0xf9)
-            free.add(0xff)
-            free.removeAll(listOf(SCRATCH_B1, SCRATCH_REG, SCRATCH_REG_X, SCRATCH_W1, SCRATCH_W1+1, SCRATCH_W2, SCRATCH_W2+1))
-            free.removeAll(listOf(0xa0, 0xa1, 0xa2, 0x91, 0xc0, 0xc5, 0xcb, 0xf5, 0xf6))        // these are updated by IRQ
-        } else {
-            if(options.zeropage== ZeropageType.KERNALSAFE) {
-                // add the Zp addresses that are just used by BASIC routines to the free list
-                free.addAll(listOf(0x09, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10, 0x11,
-                        0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, 0x20, 0x21,
-                        0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f, 0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46,
-                        0x47, 0x48, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f, 0x51, 0x52, 0x53, 0x6f, 0x70))
-            }
-            // add the other free Zp addresses
-            // these are valid for the C-64 (when no RS232 I/O is performed):
-            free.addAll(listOf(0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0d, 0x0e,
-                    0x94, 0x95, 0xa7, 0xa8, 0xa9, 0xaa,
-                    0xb5, 0xb6, 0xf7, 0xf8, 0xf9))
-        }
-        assert(SCRATCH_B1 !in free)
-        assert(SCRATCH_REG !in free)
-        assert(SCRATCH_REG_X !in free)
-        assert(SCRATCH_W1 !in free)
-        assert(SCRATCH_W2 !in free)
-
-        for(reserved in options.zpReserved)
-            reserve(reserved)
-    }
-}
-
-
-data class Mflpt5(val b0: Short, val b1: Short, val b2: Short, val b3: Short, val b4: Short) {
-
-    companion object {
-        const val MemorySize = 5
-
-        val zero = Mflpt5(0, 0,0,0,0)
-        fun fromNumber(num: Number): Mflpt5 {
-            // see https://en.wikipedia.org/wiki/Microsoft_Binary_Format
-            // and https://sourceforge.net/p/acme-crossass/code-0/62/tree/trunk/ACME_Lib/cbm/mflpt.a
-            // and https://en.wikipedia.org/wiki/IEEE_754-1985
-
-            val flt = num.toDouble()
-            if(flt < FLOAT_MAX_NEGATIVE || flt > FLOAT_MAX_POSITIVE)
-                throw CompilerException("floating point number out of 5-byte mflpt range: $this")
-            if(flt==0.0)
-                return zero
-
-            val sign = if(flt<0.0) 0x80L else 0x00L
-            var exponent = 128 + 32	// 128 is cbm's bias, 32 is this algo's bias
-            var mantissa = flt.absoluteValue
-
-            // if mantissa is too large, shift right and adjust exponent
-            while(mantissa >= 0x100000000) {
-                mantissa /= 2.0
-                exponent ++
-            }
-            // if mantissa is too small, shift left and adjust exponent
-            while(mantissa < 0x80000000) {
-                mantissa *= 2.0
-                exponent --
-            }
-
-            return when {
-                exponent<0 -> zero  // underflow, use zero instead
-                exponent>255 -> throw CompilerException("floating point overflow: $this")
-                exponent==0 -> zero
-                else -> {
-                    val mantLong = mantissa.toLong()
-                    Mflpt5(
-                            exponent.toShort(),
-                            (mantLong.and(0x7f000000L) ushr 24).or(sign).toShort(),
-                            (mantLong.and(0x00ff0000L) ushr 16).toShort(),
-                            (mantLong.and(0x0000ff00L) ushr 8).toShort(),
-                            (mantLong.and(0x000000ffL)).toShort())
-                }
-            }
-        }
-    }
-
-    fun toDouble(): Double {
-        if(this == zero) return 0.0
-        val exp = b0 - 128
-        val sign = (b1.toInt() and 0x80) > 0
-        val number = 0x80000000L.or(b1.toLong() shl 24).or(b2.toLong() shl 16).or(b3.toLong() shl 8).or(b4.toLong())
-        val result = number.toDouble() * (2.0).pow(exp) / 0x100000000
-        return if(sign) -result else result
-    }
-}
-
-object Charset {
-    private val normalImg = ImageIO.read(javaClass.getResource("/charset/c64/charset-normal.png"))
-    private val shiftedImg = ImageIO.read(javaClass.getResource("/charset/c64/charset-shifted.png"))
-
-    private fun scanChars(img: BufferedImage): Array<BufferedImage> {
-
-        val transparent = BufferedImage(img.width, img.height, BufferedImage.TYPE_INT_ARGB)
-        transparent.createGraphics().drawImage(img, 0, 0, null)
-
-        val black = Color(0,0,0).rgb
-        val nopixel = Color(0,0,0,0).rgb
-        for(y in 0 until transparent.height) {
-            for(x in 0 until transparent.width) {
-                val col = transparent.getRGB(x, y)
-                if(col==black)
-                    transparent.setRGB(x, y, nopixel)
-            }
-        }
-
-        val numColumns = transparent.width / 8
-        val charImages = (0..255).map {
-            val charX = it % numColumns
-            val charY = it/ numColumns
-            transparent.getSubimage(charX*8, charY*8, 8, 8)
-        }
-        return charImages.toTypedArray()
-    }
-
-    val normalChars = scanChars(normalImg)
-    val shiftedChars = scanChars(shiftedImg)
-}

compiler/src/prog8/compiler/target/c64/codegen/AsmOptimizer.kt

@@ -1,6 +1,8 @@
-package prog8.compiler.target.c64
+package prog8.compiler.target.c64.codegen
+
+
+// note: see https://wiki.nesdev.com/w/index.php/6502_assembly_optimisations
 
-import prog8.compiler.toHex
 
 fun optimizeAssembly(lines: MutableList<String>): Int {
 
@@ -8,67 +10,114 @@ fun optimizeAssembly(lines: MutableList<String>): Int {
 
     var linesByFour = getLinesBy(lines, 4)
 
-    var removeLines = optimizeUselessStackByteWrites(linesByFour)
+    var mods = optimizeUselessStackByteWrites(linesByFour)
-    if(removeLines.isNotEmpty()) {
+    if(mods.isNotEmpty()) {
-        for (i in removeLines.reversed())
+        apply(mods, lines)
-            lines.removeAt(i)
         linesByFour = getLinesBy(lines, 4)
         numberOfOptimizations++
     }
 
-    removeLines = optimizeIncDec(linesByFour)
+    mods = optimizeIncDec(linesByFour)
-    if(removeLines.isNotEmpty()) {
+    if(mods.isNotEmpty()) {
-        for (i in removeLines.reversed())
+        apply(mods, lines)
-            lines.removeAt(i)
         linesByFour = getLinesBy(lines, 4)
         numberOfOptimizations++
     }
 
-    removeLines = optimizeStoreLoadSame(linesByFour)
+    mods = optimizeCmpSequence(linesByFour)
-    if(removeLines.isNotEmpty()) {
+    if(mods.isNotEmpty()) {
-        for (i in removeLines.reversed())
+        apply(mods, lines)
-            lines.removeAt(i)
+        linesByFour = getLinesBy(lines, 4)
+        numberOfOptimizations++
+    }
+
+    mods = optimizeStoreLoadSame(linesByFour)
+    if(mods.isNotEmpty()) {
+        apply(mods, lines)
+        linesByFour = getLinesBy(lines, 4)
+        numberOfOptimizations++
+    }
+
+    mods= optimizeJsrRts(linesByFour)
+    if(mods.isNotEmpty()) {
+        apply(mods, lines)
+        linesByFour = getLinesBy(lines, 4)
         numberOfOptimizations++
     }
 
     var linesByFourteen = getLinesBy(lines, 14)
-    removeLines = optimizeSameAssignments(linesByFourteen)
+    mods = optimizeSameAssignments(linesByFourteen)
-    if(removeLines.isNotEmpty()) {
+    if(mods.isNotEmpty()) {
-        for (i in removeLines.reversed())
+        apply(mods, lines)
-            lines.removeAt(i)
+        linesByFourteen = getLinesBy(lines, 14)
         numberOfOptimizations++
     }
 
-    // TODO more assembly optimizations?
+    // TODO more assembly optimizations
 
     return numberOfOptimizations
 }
 
-fun optimizeUselessStackByteWrites(linesByFour: List<List<IndexedValue<String>>>): List<Int> {
+private class Modification(val lineIndex: Int, val remove: Boolean, val replacement: String?)
-    // sta on stack, dex, inx, lda from stack -> eliminate this useless stack byte write
+
-    // this is a lot harder for word values because the instruction sequence varies.
+private fun apply(modifications: List<Modification>, lines: MutableList<String>) {
-    val removeLines = mutableListOf<Int>()
+    for (modification in modifications.sortedBy { it.lineIndex }.reversed()) {
-    for(lines in linesByFour) {
+        if(modification.remove)
-        if(lines[0].value.trim()=="sta  ${ESTACK_LO.toHex()},x" &&
+            lines.removeAt(modification.lineIndex)
-                lines[1].value.trim()=="dex" &&
+        else
-                lines[2].value.trim()=="inx" &&
+            lines[modification.lineIndex] = modification.replacement!!
-                lines[3].value.trim()=="lda  ${ESTACK_LO.toHex()},x") {
-            removeLines.add(lines[0].index)
-            removeLines.add(lines[1].index)
-            removeLines.add(lines[2].index)
-            removeLines.add(lines[3].index)
-        }
     }
-    return removeLines
 }
 
-fun optimizeSameAssignments(linesByFourteen: List<List<IndexedValue<String>>>): List<Int> {
+private fun getLinesBy(lines: MutableList<String>, windowSize: Int) =
+// all lines (that aren't empty or comments) in sliding windows of certain size
+        lines.withIndex().filter { it.value.isNotBlank() && !it.value.trimStart().startsWith(';') }.windowed(windowSize, partialWindows = false)
 
-    // optimize sequential assignments of the same value to various targets (bytes, words, floats)
+private fun optimizeCmpSequence(linesByFour: List<List<IndexedValue<String>>>): List<Modification> {
+    // the when statement (on bytes) generates a sequence of:
+    //	 lda $ce01,x
+    //	 cmp #$20
+    //	 beq  check_prog8_s72choice_32
+    //	 lda $ce01,x
+    //	 cmp #$21
+    //	 beq  check_prog8_s73choice_33
+    // the repeated lda can be removed
+    val mods = mutableListOf<Modification>()
+    for(lines in linesByFour) {
+        if(lines[0].value.trim()=="lda  P8ESTACK_LO+1,x" &&
+                lines[1].value.trim().startsWith("cmp ") &&
+                lines[2].value.trim().startsWith("beq ") &&
+                lines[3].value.trim()=="lda  P8ESTACK_LO+1,x") {
+            mods.add(Modification(lines[3].index, true, null)) // remove the second lda
+        }
+    }
+    return mods
+}
+
+private fun optimizeUselessStackByteWrites(linesByFour: List<List<IndexedValue<String>>>): List<Modification> {
+    // sta on stack, dex, inx, lda from stack -> eliminate this useless stack byte write
+    // this is a lot harder for word values because the instruction sequence varies.
+    val mods = mutableListOf<Modification>()
+    for(lines in linesByFour) {
+        if(lines[0].value.trim()=="sta  P8ESTACK_LO,x" &&
+                lines[1].value.trim()=="dex" &&
+                lines[2].value.trim()=="inx" &&
+                lines[3].value.trim()=="lda  P8ESTACK_LO,x") {
+            mods.add(Modification(lines[1].index, true, null))
+            mods.add(Modification(lines[2].index, true, null))
+            mods.add(Modification(lines[3].index, true, null))
+        }
+    }
+    return mods
+}
+
+private fun optimizeSameAssignments(linesByFourteen: List<List<IndexedValue<String>>>): List<Modification> {
+
+    // optimize sequential assignments of the isSameAs value to various targets (bytes, words, floats)
     // the float one is the one that requires 2*7=14 lines of code to check...
-    // @todo a better place to do this is in the Compiler instead and work on opcodes, and never even create the inefficient asm...
+    // @todo a better place to do this is in the Compiler instead and transform the Ast, or the AsmGen, and never even create the inefficient asm in the first place...
 
-    val removeLines = mutableListOf<Int>()
+    val mods = mutableListOf<Modification>()
     for (pair in linesByFourteen) {
         val first = pair[0].value.trimStart()
         val second = pair[1].value.trimStart()
@@ -86,9 +135,9 @@ fun optimizeSameAssignments(linesByFourteen: List<List<IndexedValue<String>>>):
             val thirdvalue = fifth.substring(4)
             val fourthvalue = sixth.substring(4)
             if(firstvalue==thirdvalue && secondvalue==fourthvalue) {
-                // lda/ldy   sta/sty   twice the same word -->  remove second lda/ldy pair (fifth and sixth lines)
+                // lda/ldy   sta/sty   twice the isSameAs word -->  remove second lda/ldy pair (fifth and sixth lines)
-                removeLines.add(pair[4].index)
+                mods.add(Modification(pair[4].index, true, null))
-                removeLines.add(pair[5].index)
+                mods.add(Modification(pair[5].index, true, null))
             }
         }
 
@@ -96,8 +145,8 @@ fun optimizeSameAssignments(linesByFourteen: List<List<IndexedValue<String>>>):
             val firstvalue = first.substring(4)
             val secondvalue = third.substring(4)
             if(firstvalue==secondvalue) {
-                // lda value / sta ? / lda same-value / sta ?  -> remove second lda (third line)
+                // lda value / sta ? / lda isSameAs-value / sta ?  -> remove second lda (third line)
-                removeLines.add(pair[2].index)
+                mods.add(Modification(pair[2].index, true, null))
             }
         }
 
@@ -116,24 +165,20 @@ fun optimizeSameAssignments(linesByFourteen: List<List<IndexedValue<String>>>):
 
                 if(first.substring(4) == eighth.substring(4) && second.substring(4)==nineth.substring(4)) {
                     // identical float init
-                    removeLines.add(pair[7].index)
+                    mods.add(Modification(pair[7].index, true, null))
-                    removeLines.add(pair[8].index)
+                    mods.add(Modification(pair[8].index, true, null))
-                    removeLines.add(pair[9].index)
+                    mods.add(Modification(pair[9].index, true, null))
-                    removeLines.add(pair[10].index)
+                    mods.add(Modification(pair[10].index, true, null))
                 }
             }
         }
     }
-    return removeLines
+    return mods
 }
 
-private fun getLinesBy(lines: MutableList<String>, windowSize: Int) =
+private fun optimizeStoreLoadSame(linesByFour: List<List<IndexedValue<String>>>): List<Modification> {
-// all lines (that aren't empty or comments) in sliding pairs of 2
-        lines.withIndex().filter { it.value.isNotBlank() && !it.value.trimStart().startsWith(';') }.windowed(windowSize, partialWindows = false)
-
-private fun optimizeStoreLoadSame(linesByFour: List<List<IndexedValue<String>>>): List<Int> {
     // sta X + lda X,  sty X + ldy X,   stx X + ldx X  -> the second instruction can be eliminated
-    val removeLines = mutableListOf<Int>()
+    val mods = mutableListOf<Modification>()
     for (pair in linesByFour) {
         val first = pair[0].value.trimStart()
         val second = pair[1].value.trimStart()
@@ -151,26 +196,40 @@ private fun optimizeStoreLoadSame(linesByFour: List<List<IndexedValue<String>>>)
             val firstLoc = first.substring(4)
             val secondLoc = second.substring(4)
             if (firstLoc == secondLoc) {
-                removeLines.add(pair[1].index)
+                mods.add(Modification(pair[1].index, true, null))
             }
         }
     }
-    return removeLines
+    return mods
 }
 
-private fun optimizeIncDec(linesByTwo: List<List<IndexedValue<String>>>): List<Int> {
+private fun optimizeIncDec(linesByFour: List<List<IndexedValue<String>>>): List<Modification> {
     // sometimes, iny+dey / inx+dex / dey+iny / dex+inx sequences are generated, these can be eliminated.
-    val removeLines = mutableListOf<Int>()
+    val mods = mutableListOf<Modification>()
-    for (pair in linesByTwo) {
+    for (pair in linesByFour) {
         val first = pair[0].value
         val second = pair[1].value
         if ((" iny" in first || "\tiny" in first) && (" dey" in second || "\tdey" in second)
                 || (" inx" in first || "\tinx" in first) && (" dex" in second || "\tdex" in second)
                 || (" dey" in first || "\tdey" in first) && (" iny" in second || "\tiny" in second)
                 || (" dex" in first || "\tdex" in first) && (" inx" in second || "\tinx" in second)) {
-            removeLines.add(pair[0].index)
+            mods.add(Modification(pair[0].index, true, null))
-            removeLines.add(pair[1].index)
+            mods.add(Modification(pair[1].index, true, null))
         }
     }
-    return removeLines
+    return mods
+}
+
+private fun optimizeJsrRts(linesByFour: List<List<IndexedValue<String>>>): List<Modification> {
+    // jsr Sub + rts -> jmp Sub
+    val mods = mutableListOf<Modification>()
+    for (pair in linesByFour) {
+        val first = pair[0].value
+        val second = pair[1].value
+        if ((" jsr" in first || "\tjsr" in first ) && (" rts" in second || "\trts" in second)) {
+            mods += Modification(pair[0].index, false, pair[0].value.replace("jsr", "jmp"))
+            mods += Modification(pair[1].index, true, null)
+        }
+    }
+    return mods
 }

compiler/src/prog8/compiler/target/c64/codegen/BuiltinFunctionsAsmGen.kt

@@ -0,0 +1,509 @@
+package prog8.compiler.target.c64.codegen
+
+import prog8.ast.IFunctionCall
+import prog8.ast.Program
+import prog8.ast.base.*
+import prog8.ast.expressions.*
+import prog8.ast.statements.FunctionCallStatement
+import prog8.compiler.AssemblyError
+import prog8.compiler.toHex
+import prog8.functions.FSignature
+
+internal class BuiltinFunctionsAsmGen(private val program: Program, private val asmgen: AsmGen) {
+
+    internal fun translateFunctioncallExpression(fcall: FunctionCall, func: FSignature) {
+        translateFunctioncall(fcall, func, false)
+    }
+
+    internal fun translateFunctioncallStatement(fcall: FunctionCallStatement, func: FSignature) {
+        translateFunctioncall(fcall, func, true)
+    }
+
+    private fun translateFunctioncall(fcall: IFunctionCall, func: FSignature, discardResult: Boolean) {
+        val functionName = fcall.target.nameInSource.last()
+        if (discardResult) {
+            if (func.pure)
+                return  // can just ignore the whole function call altogether
+            else if (func.returntype != null)
+                throw AssemblyError("discarding result of non-pure function $fcall")
+        }
+
+        when (functionName) {
+            "msb" -> funcMsb(fcall)
+            "lsb" -> funcLsb(fcall)
+            "mkword" -> funcMkword(fcall, func)
+            "abs" -> funcAbs(fcall, func)
+            "swap" -> funcSwap(fcall)
+            "strlen" -> funcStrlen(fcall)
+            "min", "max", "sum" -> funcMinMaxSum(fcall, functionName)
+            "any", "all" -> funcAnyAll(fcall, functionName)
+            "sgn" -> funcSgn(fcall, func)
+            "sin", "cos", "tan", "atan",
+            "ln", "log2", "sqrt", "rad",
+            "deg", "round", "floor", "ceil",
+            "rdnf" -> funcVariousFloatFuncs(fcall, func, functionName)
+            "rol" -> funcRol(fcall)
+            "rol2" -> funcRol2(fcall)
+            "ror" -> funcRor(fcall)
+            "ror2" -> funcRor2(fcall)
+            "sort" -> funcSort(fcall)
+            "reverse" -> funcReverse(fcall)
+            "rsave" -> {
+                // save cpu status flag and all registers A, X, Y.
+                // see http://6502.org/tutorials/register_preservation.html
+                asmgen.out(" php |  sta  P8ZP_SCRATCH_REG | pha  | txa  | pha  | tya  | pha  | lda  P8ZP_SCRATCH_REG")
+            }
+            "rrestore" -> {
+                // restore all registers and cpu status flag
+                asmgen.out(" pla |  tay |  pla |  tax |  pla |  plp")
+            }
+            "clear_carry" -> asmgen.out("  clc")
+            "set_carry" -> asmgen.out("  sec")
+            "clear_irqd" -> asmgen.out("  cli")
+            "set_irqd" -> asmgen.out("  sei")
+            else -> {
+                translateFunctionArguments(fcall.args, func)
+                asmgen.out("  jsr  prog8_lib.func_$functionName")
+            }
+        }
+    }
+
+    private fun funcReverse(fcall: IFunctionCall) {
+        val variable = fcall.args.single()
+        if (variable is IdentifierReference) {
+            val decl = variable.targetVarDecl(program.namespace)!!
+            val varName = asmgen.asmVariableName(variable)
+            val numElements = decl.arraysize!!.constIndex()
+            when (decl.datatype) {
+                DataType.ARRAY_UB, DataType.ARRAY_B -> {
+                    asmgen.out("""
+                                    lda  #<$varName
+                                    ldy  #>$varName
+                                    sta  P8ZP_SCRATCH_W1
+                                    sty  P8ZP_SCRATCH_W1+1
+                                    lda  #$numElements
+                                    jsr  prog8_lib.reverse_b
+                                """)
+                }
+                DataType.ARRAY_UW, DataType.ARRAY_W -> {
+                    asmgen.out("""
+                                    lda  #<$varName
+                                    ldy  #>$varName
+                                    sta  P8ZP_SCRATCH_W1
+                                    sty  P8ZP_SCRATCH_W1+1
+                                    lda  #$numElements
+                                    jsr  prog8_lib.reverse_w
+                                """)
+                }
+                DataType.ARRAY_F -> {
+                    asmgen.out("""
+                                    lda  #<$varName
+                                    ldy  #>$varName
+                                    sta  P8ZP_SCRATCH_W1
+                                    sty  P8ZP_SCRATCH_W1+1
+                                    lda  #$numElements
+                                    jsr  prog8_lib.reverse_f
+                                """)
+                }
+                else -> throw AssemblyError("weird type")
+            }
+        }
+    }
+
+    private fun funcSort(fcall: IFunctionCall) {
+        val variable = fcall.args.single()
+        if (variable is IdentifierReference) {
+            val decl = variable.targetVarDecl(program.namespace)!!
+            val varName = asmgen.asmVariableName(variable)
+            val numElements = decl.arraysize!!.constIndex()
+            when (decl.datatype) {
+                DataType.ARRAY_UB, DataType.ARRAY_B -> {
+                    asmgen.out("""
+                                    lda  #<$varName
+                                    ldy  #>$varName
+                                    sta  P8ZP_SCRATCH_W1
+                                    sty  P8ZP_SCRATCH_W1+1
+                                    lda  #$numElements
+                                    sta  P8ZP_SCRATCH_B1
+                                """)
+                    asmgen.out(if (decl.datatype == DataType.ARRAY_UB) "  jsr  prog8_lib.sort_ub" else "  jsr  prog8_lib.sort_b")
+                }
+                DataType.ARRAY_UW, DataType.ARRAY_W -> {
+                    asmgen.out("""
+                                    lda  #<$varName
+                                    ldy  #>$varName
+                                    sta  P8ZP_SCRATCH_W1
+                                    sty  P8ZP_SCRATCH_W1+1
+                                    lda  #$numElements
+                                    sta  P8ZP_SCRATCH_B1
+                                """)
+                    asmgen.out(if (decl.datatype == DataType.ARRAY_UW) "  jsr  prog8_lib.sort_uw" else "  jsr  prog8_lib.sort_w")
+                }
+                DataType.ARRAY_F -> throw AssemblyError("sorting of floating point array is not supported")
+                else -> throw AssemblyError("weird type")
+            }
+        } else
+            throw AssemblyError("weird type")
+    }
+
+    private fun funcRor2(fcall: IFunctionCall) {
+        val what = fcall.args.single()
+        val dt = what.inferType(program)
+        when (dt.typeOrElse(DataType.STRUCT)) {
+            DataType.UBYTE -> {
+                when (what) {
+                    is ArrayIndexedExpression -> {
+                        asmgen.translateExpression(what.identifier)
+                        asmgen.translateExpression(what.arrayspec.index)
+                        asmgen.out("  jsr  prog8_lib.ror2_array_ub")
+                    }
+                    is DirectMemoryRead -> {
+                        if (what.addressExpression is NumericLiteralValue) {
+                            val number = (what.addressExpression as NumericLiteralValue).number
+                            asmgen.out("  lda  ${number.toHex()} |  lsr  a |  bcc  + |  ora  #\$80 |+  |  sta  ${number.toHex()}")
+                        } else {
+                            asmgen.translateExpression(what.addressExpression)
+                            asmgen.out("  jsr  prog8_lib.ror2_mem_ub")
+                        }
+                    }
+                    is IdentifierReference -> {
+                        val variable = asmgen.asmVariableName(what)
+                        asmgen.out("  lda  $variable |  lsr  a |  bcc  + |  ora  #\$80 |+  |  sta  $variable")
+                    }
+                    else -> throw AssemblyError("weird type")
+                }
+            }
+            DataType.UWORD -> {
+                when (what) {
+                    is ArrayIndexedExpression -> {
+                        asmgen.translateExpression(what.identifier)
+                        asmgen.translateExpression(what.arrayspec.index)
+                        asmgen.out("  jsr  prog8_lib.ror2_array_uw")
+                    }
+                    is IdentifierReference -> {
+                        val variable = asmgen.asmVariableName(what)
+                        asmgen.out("  lsr  $variable+1 |  ror  $variable |  bcc  + |  lda  $variable+1 |  ora  #\$80 |  sta  $variable+1 |+  ")
+                    }
+                    else -> throw AssemblyError("weird type")
+                }
+            }
+            else -> throw AssemblyError("weird type")
+        }
+    }
+
+    private fun funcRor(fcall: IFunctionCall) {
+        val what = fcall.args.single()
+        val dt = what.inferType(program)
+        when (dt.typeOrElse(DataType.STRUCT)) {
+            DataType.UBYTE -> {
+                when (what) {
+                    is ArrayIndexedExpression -> {
+                        asmgen.translateExpression(what.identifier)
+                        asmgen.translateExpression(what.arrayspec.index)
+                        asmgen.out("  jsr  prog8_lib.ror_array_ub")
+                    }
+                    is DirectMemoryRead -> {
+                        if (what.addressExpression is NumericLiteralValue) {
+                            val number = (what.addressExpression as NumericLiteralValue).number
+                            asmgen.out("  ror  ${number.toHex()}")
+                        } else {
+                            asmgen.translateExpression(what.addressExpression)
+                            asmgen.out("""
+                        inx
+                        lda  P8ESTACK_LO,x
+                        sta  (+) + 1
+                        lda  P8ESTACK_HI,x
+                        sta  (+) + 2
+    +                   ror  ${'$'}ffff            ; modified                    
+                                        """)
+                        }
+                    }
+                    is IdentifierReference -> {
+                        val variable = asmgen.asmVariableName(what)
+                        asmgen.out("  ror  $variable")
+                    }
+                    else -> throw AssemblyError("weird type")
+                }
+            }
+            DataType.UWORD -> {
+                when (what) {
+                    is ArrayIndexedExpression -> {
+                        asmgen.translateExpression(what.identifier)
+                        asmgen.translateExpression(what.arrayspec.index)
+                        asmgen.out("  jsr  prog8_lib.ror_array_uw")
+                    }
+                    is IdentifierReference -> {
+                        val variable = asmgen.asmVariableName(what)
+                        asmgen.out("  ror  $variable+1 |  ror  $variable")
+                    }
+                    else -> throw AssemblyError("weird type")
+                }
+            }
+            else -> throw AssemblyError("weird type")
+        }
+    }
+
+    private fun funcRol2(fcall: IFunctionCall) {
+        val what = fcall.args.single()
+        val dt = what.inferType(program)
+        when (dt.typeOrElse(DataType.STRUCT)) {
+            DataType.UBYTE -> {
+                when (what) {
+                    is ArrayIndexedExpression -> {
+                        asmgen.translateExpression(what.identifier)
+                        asmgen.translateExpression(what.arrayspec.index)
+                        asmgen.out("  jsr  prog8_lib.rol2_array_ub")
+                    }
+                    is DirectMemoryRead -> {
+                        if (what.addressExpression is NumericLiteralValue) {
+                            val number = (what.addressExpression as NumericLiteralValue).number
+                            asmgen.out("  lda  ${number.toHex()} |  cmp  #\$80 |  rol  a |  sta  ${number.toHex()}")
+                        } else {
+                            asmgen.translateExpression(what.addressExpression)
+                            asmgen.out("  jsr  prog8_lib.rol2_mem_ub")
+                        }
+                    }
+                    is IdentifierReference -> {
+                        val variable = asmgen.asmVariableName(what)
+                        asmgen.out("  lda  $variable |  cmp  #\$80 |  rol  a |  sta  $variable")
+                    }
+                    else -> throw AssemblyError("weird type")
+                }
+            }
+            DataType.UWORD -> {
+                when (what) {
+                    is ArrayIndexedExpression -> {
+                        asmgen.translateExpression(what.identifier)
+                        asmgen.translateExpression(what.arrayspec.index)
+                        asmgen.out("  jsr  prog8_lib.rol2_array_uw")
+                    }
+                    is IdentifierReference -> {
+                        val variable = asmgen.asmVariableName(what)
+                        asmgen.out("  asl  $variable |  rol  $variable+1 |  bcc  + |  inc  $variable |+  ")
+                    }
+                    else -> throw AssemblyError("weird type")
+                }
+            }
+            else -> throw AssemblyError("weird type")
+        }
+    }
+
+    private fun funcRol(fcall: IFunctionCall) {
+        val what = fcall.args.single()
+        val dt = what.inferType(program)
+        when (dt.typeOrElse(DataType.STRUCT)) {
+            DataType.UBYTE -> {
+                when (what) {
+                    is ArrayIndexedExpression -> {
+                        asmgen.translateExpression(what.identifier)
+                        asmgen.translateExpression(what.arrayspec.index)
+                        asmgen.out("  jsr  prog8_lib.rol_array_ub")
+                    }
+                    is DirectMemoryRead -> {
+                        if (what.addressExpression is NumericLiteralValue) {
+                            val number = (what.addressExpression as NumericLiteralValue).number
+                            asmgen.out("  rol  ${number.toHex()}")
+                        } else {
+                            asmgen.translateExpression(what.addressExpression)
+                            asmgen.out("""
+                        inx
+                        lda  P8ESTACK_LO,x
+                        sta  (+) + 1
+                        lda  P8ESTACK_HI,x
+                        sta  (+) + 2
+    +                   rol  ${'$'}ffff            ; modified                    
+                                        """)
+                        }
+                    }
+                    is IdentifierReference -> {
+                        val variable = asmgen.asmVariableName(what)
+                        asmgen.out("  rol  $variable")
+                    }
+                    else -> throw AssemblyError("weird type")
+                }
+            }
+            DataType.UWORD -> {
+                when (what) {
+                    is ArrayIndexedExpression -> {
+                        asmgen.translateExpression(what.identifier)
+                        asmgen.translateExpression(what.arrayspec.index)
+                        asmgen.out("  jsr  prog8_lib.rol_array_uw")
+                    }
+                    is IdentifierReference -> {
+                        val variable = asmgen.asmVariableName(what)
+                        asmgen.out("  rol  $variable |  rol  $variable+1")
+                    }
+                    else -> throw AssemblyError("weird type")
+                }
+            }
+            else -> throw AssemblyError("weird type")
+        }
+    }
+
+    private fun funcVariousFloatFuncs(fcall: IFunctionCall, func: FSignature, functionName: String) {
+        translateFunctionArguments(fcall.args, func)
+        asmgen.out("  jsr  c64flt.func_$functionName")
+    }
+
+    private fun funcSgn(fcall: IFunctionCall, func: FSignature) {
+        translateFunctionArguments(fcall.args, func)
+        val dt = fcall.args.single().inferType(program)
+        when (dt.typeOrElse(DataType.STRUCT)) {
+            DataType.UBYTE -> asmgen.out("  jsr  math.sign_ub")
+            DataType.BYTE -> asmgen.out("  jsr  math.sign_b")
+            DataType.UWORD -> asmgen.out("  jsr  math.sign_uw")
+            DataType.WORD -> asmgen.out("  jsr  math.sign_w")
+            DataType.FLOAT -> asmgen.out("  jsr  c64flt.sign_f")
+            else -> throw AssemblyError("weird type $dt")
+        }
+    }
+
+    private fun funcAnyAll(fcall: IFunctionCall, functionName: String) {
+        outputPushAddressAndLenghtOfArray(fcall.args[0])
+        val dt = fcall.args.single().inferType(program)
+        when (dt.typeOrElse(DataType.STRUCT)) {
+            DataType.ARRAY_B, DataType.ARRAY_UB, DataType.STR -> asmgen.out("  jsr  prog8_lib.func_${functionName}_b")
+            DataType.ARRAY_UW, DataType.ARRAY_W -> asmgen.out("  jsr  prog8_lib.func_${functionName}_w")
+            DataType.ARRAY_F -> asmgen.out("  jsr  c64flt.func_${functionName}_f")
+            else -> throw AssemblyError("weird type $dt")
+        }
+    }
+
+    private fun funcMinMaxSum(fcall: IFunctionCall, functionName: String) {
+        outputPushAddressAndLenghtOfArray(fcall.args[0])
+        val dt = fcall.args.single().inferType(program)
+        when (dt.typeOrElse(DataType.STRUCT)) {
+            DataType.ARRAY_UB, DataType.STR -> asmgen.out("  jsr  prog8_lib.func_${functionName}_ub")
+            DataType.ARRAY_B -> asmgen.out("  jsr  prog8_lib.func_${functionName}_b")
+            DataType.ARRAY_UW -> asmgen.out("  jsr  prog8_lib.func_${functionName}_uw")
+            DataType.ARRAY_W -> asmgen.out("  jsr  prog8_lib.func_${functionName}_w")
+            DataType.ARRAY_F -> asmgen.out("  jsr  c64flt.func_${functionName}_f")
+            else -> throw AssemblyError("weird type $dt")
+        }
+    }
+
+    private fun funcStrlen(fcall: IFunctionCall) {
+        val name = asmgen.asmVariableName(fcall.args[0] as IdentifierReference)
+        asmgen.out("""
+            lda  #<$name
+            ldy  #>$name
+            jsr  prog8_lib.strlen
+            sta  P8ESTACK_LO,x
+            dex""")
+    }
+
+    private fun funcSwap(fcall: IFunctionCall) {
+        val first = fcall.args[0]
+        val second = fcall.args[1]
+        if(first is IdentifierReference && second is IdentifierReference) {
+            val firstName = asmgen.asmVariableName(first)
+            val secondName = asmgen.asmVariableName(second)
+            val dt = first.inferType(program)
+            if(dt.istype(DataType.BYTE) || dt.istype(DataType.UBYTE)) {
+                asmgen.out(" ldy  $firstName |  lda  $secondName |  sta  $firstName |  tya |  sta  $secondName")
+                return
+            }
+            if(dt.istype(DataType.WORD) || dt.istype(DataType.UWORD)) {
+                asmgen.out("""
+                    ldy  $firstName
+                    lda  $secondName
+                    sta  $firstName
+                    sty  $secondName
+                    ldy  $firstName+1
+                    lda  $secondName+1
+                    sta  $firstName+1
+                    sty  $secondName+1
+                """)
+                return
+            }
+            if(dt.istype(DataType.FLOAT)) {
+                asmgen.out("""
+                    lda  #<$firstName
+                    sta  P8ZP_SCRATCH_W1
+                    lda  #>$firstName
+                    sta  P8ZP_SCRATCH_W1+1
+                    lda  #<$secondName
+                    sta  P8ZP_SCRATCH_W2
+                    lda  #>$secondName
+                    sta  P8ZP_SCRATCH_W2+1
+                    jsr  c64flt.swap_floats
+                """)
+                return
+            }
+        }
+
+        // other types of swap() calls should have been replaced by a different statement sequence involving a temp variable
+        throw AssemblyError("no asm generation for swap funccall $fcall")
+    }
+
+    private fun funcAbs(fcall: IFunctionCall, func: FSignature) {
+        translateFunctionArguments(fcall.args, func)
+        val dt = fcall.args.single().inferType(program)
+        when (dt.typeOrElse(DataType.STRUCT)) {
+            in ByteDatatypes -> asmgen.out("  jsr  prog8_lib.abs_b")
+            in WordDatatypes -> asmgen.out("  jsr  prog8_lib.abs_w")
+            DataType.FLOAT -> asmgen.out("  jsr  c64flt.abs_f")
+            else -> throw AssemblyError("weird type")
+        }
+    }
+
+    private fun funcMkword(fcall: IFunctionCall, func: FSignature) {
+        // trick: push the args in reverse order (msb first, lsb second) this saves some instructions
+        asmgen.translateExpression(fcall.args[1])
+        asmgen.translateExpression(fcall.args[0])
+        asmgen.out("  inx | lda  P8ESTACK_LO,x  | sta  P8ESTACK_HI+1,x")
+    }
+
+    private fun funcMsb(fcall: IFunctionCall) {
+        val arg = fcall.args.single()
+        if (arg.inferType(program).typeOrElse(DataType.STRUCT) !in WordDatatypes)
+            throw AssemblyError("msb required word argument")
+        if (arg is NumericLiteralValue)
+            throw AssemblyError("msb(const) should have been const-folded away")
+        if (arg is IdentifierReference) {
+            val sourceName = asmgen.asmVariableName(arg)
+            asmgen.out("  lda  $sourceName+1 |  sta  P8ESTACK_LO,x |  dex")
+        } else {
+            asmgen.translateExpression(arg)
+            asmgen.out("  lda  P8ESTACK_HI+1,x |  sta  P8ESTACK_LO+1,x")
+        }
+    }
+
+    private fun funcLsb(fcall: IFunctionCall) {
+        val arg = fcall.args.single()
+        if (arg.inferType(program).typeOrElse(DataType.STRUCT) !in WordDatatypes)
+            throw AssemblyError("lsb required word argument")
+        if (arg is NumericLiteralValue)
+            throw AssemblyError("lsb(const) should have been const-folded away")
+        if (arg is IdentifierReference) {
+            val sourceName = asmgen.asmVariableName(arg)
+            asmgen.out("  lda  $sourceName |  sta  P8ESTACK_LO,x |  dex")
+        } else {
+            asmgen.translateExpression(arg)
+            // just ignore any high-byte
+        }
+    }
+
+    private fun outputPushAddressAndLenghtOfArray(arg: Expression) {
+        arg as IdentifierReference
+        val identifierName = asmgen.asmVariableName(arg)
+        val size = arg.targetVarDecl(program.namespace)!!.arraysize!!.constIndex()!!
+        asmgen.out("""
+                    lda  #<$identifierName
+                    sta  P8ESTACK_LO,x
+                    lda  #>$identifierName
+                    sta  P8ESTACK_HI,x
+                    dex
+                    lda  #$size
+                    sta  P8ESTACK_LO,x
+                    dex
+                    """)
+    }
+
+    private fun translateFunctionArguments(args: MutableList<Expression>, signature: FSignature) {
+        args.forEach {
+            asmgen.translateExpression(it)
+        }
+    }
+
+}

compiler/src/prog8/compiler/target/c64/codegen/ExpressionsAsmGen.kt

@@ -0,0 +1,514 @@
+package prog8.compiler.target.c64.codegen
+
+import prog8.ast.Program
+import prog8.ast.base.*
+import prog8.ast.expressions.*
+import prog8.compiler.AssemblyError
+import prog8.compiler.toHex
+import prog8.functions.BuiltinFunctions
+import kotlin.math.absoluteValue
+
+internal class ExpressionsAsmGen(private val program: Program, private val asmgen: AsmGen) {
+
+    internal fun translateExpression(expression: Expression) {
+        when(expression) {
+            is PrefixExpression -> translateExpression(expression)
+            is BinaryExpression -> translateExpression(expression)
+            is ArrayIndexedExpression -> translateExpression(expression)
+            is TypecastExpression -> translateExpression(expression)
+            is AddressOf -> translateExpression(expression)
+            is DirectMemoryRead -> translateExpression(expression)
+            is NumericLiteralValue -> translateExpression(expression)
+            is IdentifierReference -> translateExpression(expression)
+            is FunctionCall -> translateExpression(expression)
+            is ArrayLiteralValue, is StringLiteralValue -> throw AssemblyError("no asm gen for string/array literal value assignment - should have been replaced by a variable")
+            is RangeExpr -> throw AssemblyError("range expression should have been changed into array values")
+        }
+    }
+
+    private fun translateExpression(expression: FunctionCall) {
+        val functionName = expression.target.nameInSource.last()
+        val builtinFunc = BuiltinFunctions[functionName]
+        if (builtinFunc != null) {
+            asmgen.translateFunctioncallExpression(expression, builtinFunc)
+        } else {
+            val sub = expression.target.targetSubroutine(program.namespace)!!
+            asmgen.translateFunctionCall(expression)
+            val returns = sub.returntypes.zip(sub.asmReturnvaluesRegisters)
+            for ((_, reg) in returns) {
+                if (!reg.stack) {
+                    // result value in cpu or status registers, put it on the stack
+                    if (reg.registerOrPair != null) {
+                        when (reg.registerOrPair) {
+                            RegisterOrPair.A -> asmgen.out("  sta  P8ESTACK_LO,x |  dex")
+                            RegisterOrPair.Y -> asmgen.out("  tya |  sta  P8ESTACK_LO,x |  dex")
+                            RegisterOrPair.AY -> asmgen.out("  sta  P8ESTACK_LO,x |  tya |  sta  P8ESTACK_HI,x |  dex")
+                            RegisterOrPair.X -> {
+                                // return value in X register has been discarded, just push a zero
+                                asmgen.out("  lda  #0 |  sta  P8ESTACK_LO,x |  dex")
+                            }
+                            RegisterOrPair.AX -> {
+                                // return value in X register has been discarded, just push a zero in this place
+                                asmgen.out("  sta  P8ESTACK_LO,x |  lda  #0 |  sta  P8ESTACK_HI,x |  dex")
+                            }
+                            RegisterOrPair.XY -> {
+                                // return value in X register has been discarded, just push a zero in this place
+                                asmgen.out("  lda  #0 |  sta  P8ESTACK_LO,x |  tya |  sta  P8ESTACK_HI,x |  dex")
+                            }
+                        }
+                    }
+                    // return value from a statusregister is not put on the stack, it should be acted on via a conditional branch such as if_cc
+                }
+            }
+        }
+    }
+
+    private fun translateExpression(expr: TypecastExpression) {
+        translateExpression(expr.expression)
+        when(expr.expression.inferType(program).typeOrElse(DataType.STRUCT)) {
+            DataType.UBYTE -> {
+                when(expr.type) {
+                    DataType.UBYTE, DataType.BYTE -> {}
+                    DataType.UWORD, DataType.WORD -> asmgen.out("  lda  #0  |  sta  P8ESTACK_HI+1,x")
+                    DataType.FLOAT -> asmgen.out(" jsr  c64flt.stack_ub2float")
+                    in PassByReferenceDatatypes -> throw AssemblyError("cannot cast to a pass-by-reference datatype")
+                    else -> throw AssemblyError("weird type")
+                }
+            }
+            DataType.BYTE -> {
+                when(expr.type) {
+                    DataType.UBYTE, DataType.BYTE -> {}
+                    DataType.UWORD, DataType.WORD -> {
+                        // sign extend
+                        asmgen.out(""" 
+                            lda  P8ESTACK_LO+1,x
+                            ora  #$7f
+                            bmi  +
+                            lda  #0
++                           sta  P8ESTACK_HI+1,x""")
+                    }
+                    DataType.FLOAT -> asmgen.out(" jsr  c64flt.stack_b2float")
+                    in PassByReferenceDatatypes -> throw AssemblyError("cannot cast to a pass-by-reference datatype")
+                    else -> throw AssemblyError("weird type")
+                }
+            }
+            DataType.UWORD -> {
+                when(expr.type) {
+                    DataType.BYTE, DataType.UBYTE -> {}
+                    DataType.WORD, DataType.UWORD -> {}
+                    DataType.FLOAT -> asmgen.out(" jsr  c64flt.stack_uw2float")
+                    in PassByReferenceDatatypes -> throw AssemblyError("cannot cast to a pass-by-reference datatype")
+                    else -> throw AssemblyError("weird type")
+                }
+            }
+            DataType.WORD -> {
+                when(expr.type) {
+                    DataType.BYTE, DataType.UBYTE -> {}
+                    DataType.WORD, DataType.UWORD -> {}
+                    DataType.FLOAT -> asmgen.out(" jsr  c64flt.stack_w2float")
+                    in PassByReferenceDatatypes -> throw AssemblyError("cannot cast to a pass-by-reference datatype")
+                    else -> throw AssemblyError("weird type")
+                }
+            }
+            DataType.FLOAT -> {
+                when(expr.type) {
+                    DataType.UBYTE -> asmgen.out(" jsr  c64flt.stack_float2uw")
+                    DataType.BYTE -> asmgen.out(" jsr  c64flt.stack_float2w")
+                    DataType.UWORD -> asmgen.out(" jsr  c64flt.stack_float2uw")
+                    DataType.WORD -> asmgen.out(" jsr  c64flt.stack_float2w")
+                    DataType.FLOAT -> {}
+                    in PassByReferenceDatatypes -> throw AssemblyError("cannot cast to a pass-by-reference datatype")
+                    else -> throw AssemblyError("weird type")
+                }
+            }
+            in PassByReferenceDatatypes -> throw AssemblyError("cannot cast pass-by-reference value into another type")
+            else -> throw AssemblyError("weird type")
+        }
+    }
+
+    private fun translateExpression(expr: AddressOf) {
+        val name = asmgen.asmVariableName(expr.identifier)
+        asmgen.out("  lda  #<$name |  sta  P8ESTACK_LO,x |  lda  #>$name  |  sta  P8ESTACK_HI,x  | dex")
+    }
+
+    private fun translateExpression(expr: DirectMemoryRead) {
+        when(expr.addressExpression) {
+            is NumericLiteralValue -> {
+                val address = (expr.addressExpression as NumericLiteralValue).number.toInt()
+                asmgen.out("  lda  ${address.toHex()} |  sta  P8ESTACK_LO,x |  dex")
+            }
+            is IdentifierReference -> {
+                // the identifier is a pointer variable, so read the value from the address in it
+                asmgen.loadByteFromPointerIntoA(expr.addressExpression as IdentifierReference)
+                asmgen.out(" sta  P8ESTACK_LO,x |  dex")
+            }
+            else -> {
+                translateExpression(expr.addressExpression)
+                asmgen.out("  jsr  prog8_lib.read_byte_from_address_on_stack")
+                asmgen.out("  sta  P8ESTACK_LO+1,x")
+            }
+        }
+    }
+
+    private fun translateExpression(expr: NumericLiteralValue) {
+        when(expr.type) {
+            DataType.UBYTE, DataType.BYTE -> asmgen.out(" lda  #${expr.number.toHex()}  | sta  P8ESTACK_LO,x  | dex")
+            DataType.UWORD, DataType.WORD -> asmgen.out("""
+                lda  #<${expr.number.toHex()}
+                sta  P8ESTACK_LO,x
+                lda  #>${expr.number.toHex()}
+                sta  P8ESTACK_HI,x
+                dex
+            """)
+            DataType.FLOAT -> {
+                val floatConst = asmgen.getFloatAsmConst(expr.number.toDouble())
+                asmgen.out(" lda  #<$floatConst |  ldy  #>$floatConst |  jsr  c64flt.push_float")
+            }
+            else -> throw AssemblyError("weird type")
+        }
+    }
+
+    private fun translateExpression(expr: IdentifierReference) {
+        val varname = asmgen.asmVariableName(expr)
+        when(expr.inferType(program).typeOrElse(DataType.STRUCT)) {
+            DataType.UBYTE, DataType.BYTE -> {
+                asmgen.out("  lda  $varname  |  sta  P8ESTACK_LO,x  |  dex")
+            }
+            DataType.UWORD, DataType.WORD -> {
+                asmgen.out("  lda  $varname  |  sta  P8ESTACK_LO,x  |  lda  $varname+1 |  sta  P8ESTACK_HI,x |  dex")
+            }
+            DataType.FLOAT -> {
+                asmgen.out(" lda  #<$varname |  ldy  #>$varname|  jsr  c64flt.push_float")
+            }
+            in IterableDatatypes -> {
+                asmgen.out("  lda  #<$varname  |  sta  P8ESTACK_LO,x  |  lda  #>$varname |  sta  P8ESTACK_HI,x |  dex")
+            }
+            else -> throw AssemblyError("stack push weird variable type $expr")
+        }
+    }
+
+    private val optimizedByteMultiplications = setOf(3,5,6,7,9,10,11,12,13,14,15,20,25,40)
+    private val optimizedWordMultiplications = setOf(3,5,6,7,9,10,12,15,20,25,40)
+
+    private fun translateExpression(expr: BinaryExpression) {
+        val leftIDt = expr.left.inferType(program)
+        val rightIDt = expr.right.inferType(program)
+        if(!leftIDt.isKnown || !rightIDt.isKnown)
+            throw AssemblyError("can't infer type of both expression operands")
+
+        val leftDt = leftIDt.typeOrElse(DataType.STRUCT)
+        val rightDt = rightIDt.typeOrElse(DataType.STRUCT)
+        // see if we can apply some optimized routines
+        when(expr.operator) {
+            ">>" -> {
+                translateExpression(expr.left)
+                val amount = expr.right.constValue(program)?.number?.toInt()
+                if(amount!=null) {
+                    when (leftDt) {
+                        DataType.UBYTE -> {
+                            if (amount <= 2)
+                                repeat(amount) { asmgen.out(" lsr  P8ESTACK_LO+1,x") }
+                            else {
+                                asmgen.out(" lda  P8ESTACK_LO+1,x")
+                                repeat(amount) { asmgen.out(" lsr  a") }
+                                asmgen.out(" sta  P8ESTACK_LO+1,x")
+                            }
+                        }
+                        DataType.BYTE -> {
+                            if (amount <= 2)
+                                repeat(amount) { asmgen.out(" lda  P8ESTACK_LO+1,x |  asl  a |  ror  P8ESTACK_LO+1,x") }
+                            else {
+                                asmgen.out(" lda  P8ESTACK_LO+1,x |  sta  P8ZP_SCRATCH_B1")
+                                repeat(amount) { asmgen.out(" asl  a |  ror  P8ZP_SCRATCH_B1 |  lda  P8ZP_SCRATCH_B1") }
+                                asmgen.out(" sta  P8ESTACK_LO+1,x")
+                            }
+                        }
+                        DataType.UWORD -> {
+                            var left = amount
+                            while (left >= 7) {
+                                asmgen.out(" jsr  math.shift_right_uw_7")
+                                left -= 7
+                            }
+                            if (left in 0..2)
+                                repeat(left) { asmgen.out(" lsr  P8ESTACK_HI+1,x |  ror  P8ESTACK_LO+1,x") }
+                            else
+                                asmgen.out(" jsr  math.shift_right_uw_$left")
+                        }
+                        DataType.WORD -> {
+                            var left = amount
+                            while (left >= 7) {
+                                asmgen.out(" jsr  math.shift_right_w_7")
+                                left -= 7
+                            }
+                            if (left in 0..2)
+                                repeat(left) { asmgen.out(" lda  P8ESTACK_HI+1,x |  asl a  |  ror  P8ESTACK_HI+1,x |  ror  P8ESTACK_LO+1,x") }
+                            else
+                                asmgen.out(" jsr  math.shift_right_w_$left")
+                        }
+                        else -> throw AssemblyError("weird type")
+                    }
+                    return
+                }
+            }
+            "<<" -> {
+                translateExpression(expr.left)
+                val amount = expr.right.constValue(program)?.number?.toInt()
+                if(amount!=null) {
+                    if (leftDt in ByteDatatypes) {
+                        if (amount <= 2)
+                            repeat(amount) { asmgen.out("  asl  P8ESTACK_LO+1,x") }
+                        else {
+                            asmgen.out("  lda  P8ESTACK_LO+1,x")
+                            repeat(amount) { asmgen.out("  asl  a") }
+                            asmgen.out("  sta  P8ESTACK_LO+1,x")
+                        }
+                    } else {
+                        var left = amount
+                        while (left >= 7) {
+                            asmgen.out(" jsr  math.shift_left_w_7")
+                            left -= 7
+                        }
+                        if (left in 0..2)
+                            repeat(left) { asmgen.out("  asl  P8ESTACK_LO+1,x |  rol  P8ESTACK_HI+1,x") }
+                        else
+                            asmgen.out(" jsr  math.shift_left_w_$left")
+                    }
+                    return
+                }
+            }
+            "*" -> {
+                val value = expr.right.constValue(program)
+                if(value!=null) {
+                    if(rightDt in IntegerDatatypes) {
+                        val amount = value.number.toInt()
+                        when(rightDt) {
+                            DataType.UBYTE -> {
+                                if(amount in optimizedByteMultiplications) {
+                                    translateExpression(expr.left)
+                                    asmgen.out(" jsr  math.mul_byte_$amount")
+                                    return
+                                }
+                            }
+                            DataType.BYTE -> {
+                                if(amount in optimizedByteMultiplications) {
+                                    translateExpression(expr.left)
+                                    asmgen.out(" jsr  math.mul_byte_$amount")
+                                    return
+                                }
+                                if(amount.absoluteValue in optimizedByteMultiplications) {
+                                    translateExpression(expr.left)
+                                    asmgen.out(" jsr  prog8_lib.neg_b |  jsr  math.mul_byte_${amount.absoluteValue}")
+                                    return
+                                }
+                            }
+                            DataType.UWORD -> {
+                                if(amount in optimizedWordMultiplications) {
+                                    translateExpression(expr.left)
+                                    asmgen.out(" jsr  math.mul_word_$amount")
+                                    return
+                                }
+                            }
+                            DataType.WORD -> {
+                                if(amount in optimizedWordMultiplications) {
+                                    translateExpression(expr.left)
+                                    asmgen.out(" jsr  math.mul_word_$amount")
+                                    return
+                                }
+                                if(amount.absoluteValue in optimizedWordMultiplications) {
+                                    translateExpression(expr.left)
+                                    asmgen.out(" jsr  prog8_lib.neg_w |  jsr  math.mul_word_${amount.absoluteValue}")
+                                    return
+                                }
+                            }
+                            else -> {}
+                        }
+                    }
+                }
+            }
+        }
+
+        // the general, non-optimized cases
+        translateExpression(expr.left)
+        translateExpression(expr.right)
+        if((leftDt in ByteDatatypes && rightDt !in ByteDatatypes)
+                || (leftDt in WordDatatypes && rightDt !in WordDatatypes))
+            throw AssemblyError("binary operator ${expr.operator} left/right dt not identical")
+
+        when (leftDt) {
+            in ByteDatatypes -> translateBinaryOperatorBytes(expr.operator, leftDt)
+            in WordDatatypes -> translateBinaryOperatorWords(expr.operator, leftDt)
+            DataType.FLOAT -> translateBinaryOperatorFloats(expr.operator)
+            else -> throw AssemblyError("non-numerical datatype")
+        }
+    }
+
+    private fun translateExpression(expr: PrefixExpression) {
+        translateExpression(expr.expression)
+        val type = expr.inferType(program).typeOrElse(DataType.STRUCT)
+        when(expr.operator) {
+            "+" -> {}
+            "-" -> {
+                when(type) {
+                    in ByteDatatypes -> asmgen.out("  jsr  prog8_lib.neg_b")
+                    in WordDatatypes -> asmgen.out("  jsr  prog8_lib.neg_w")
+                    DataType.FLOAT -> asmgen.out("  jsr  c64flt.neg_f")
+                    else -> throw AssemblyError("weird type")
+                }
+            }
+            "~" -> {
+                when(type) {
+                    in ByteDatatypes ->
+                        asmgen.out("""
+                            lda  P8ESTACK_LO+1,x
+                            eor  #255
+                            sta  P8ESTACK_LO+1,x
+                            """)
+                    in WordDatatypes -> asmgen.out("  jsr  prog8_lib.inv_word")
+                    else -> throw AssemblyError("weird type")
+                }
+            }
+            "not" -> {
+                when(type) {
+                    in ByteDatatypes -> asmgen.out("  jsr  prog8_lib.not_byte")
+                    in WordDatatypes -> asmgen.out("  jsr  prog8_lib.not_word")
+                    else -> throw AssemblyError("weird type")
+                }
+            }
+            else -> throw AssemblyError("invalid prefix operator ${expr.operator}")
+        }
+    }
+
+    private fun translateExpression(arrayExpr: ArrayIndexedExpression) {
+        val index = arrayExpr.arrayspec.index
+        val elementDt = arrayExpr.inferType(program).typeOrElse(DataType.STRUCT)
+        val arrayVarName = asmgen.asmVariableName(arrayExpr.identifier)
+        if(index is NumericLiteralValue) {
+            val indexValue = index.number.toInt() * elementDt.memorySize()
+            when(elementDt) {
+                in ByteDatatypes -> {
+                    asmgen.out("  lda  $arrayVarName+$indexValue |  sta  P8ESTACK_LO,x |  dex")
+                }
+                in WordDatatypes -> {
+                    asmgen.out("  lda  $arrayVarName+$indexValue |  sta  P8ESTACK_LO,x |  lda  $arrayVarName+$indexValue+1 |  sta  P8ESTACK_HI,x |  dex")
+                }
+                DataType.FLOAT -> {
+                    asmgen.out("  lda  #<$arrayVarName+$indexValue |  ldy  #>$arrayVarName+$indexValue |  jsr  c64flt.push_float")
+                }
+                else -> throw AssemblyError("weird element type")
+            }
+        } else {
+            when(elementDt) {
+                in ByteDatatypes -> {
+                    asmgen.loadScaledArrayIndexIntoRegister(arrayExpr, elementDt, CpuRegister.Y)
+                    asmgen.out(" lda  $arrayVarName,y |  sta  P8ESTACK_LO,x |  dex")
+                }
+                in WordDatatypes -> {
+                    asmgen.loadScaledArrayIndexIntoRegister(arrayExpr, elementDt, CpuRegister.Y)
+                    asmgen.out(" lda  $arrayVarName,y |  sta  P8ESTACK_LO,x |  lda  $arrayVarName+1,y |  sta  P8ESTACK_HI,x |  dex")
+                }
+                DataType.FLOAT -> {
+                    asmgen.loadScaledArrayIndexIntoRegister(arrayExpr, elementDt, CpuRegister.A)
+                    asmgen.out("""
+                        ldy  #>$arrayVarName
+                        clc
+                        adc  #<$arrayVarName
+                        bcc  +
+                        iny
++                       jsr  c64flt.push_float""")
+                }
+                else -> throw AssemblyError("weird dt")
+            }
+
+        }
+    }
+
+    private fun translateBinaryOperatorBytes(operator: String, types: DataType) {
+        when(operator) {
+            "**" -> throw AssemblyError("** operator requires floats")
+            "*" -> asmgen.out("  jsr  prog8_lib.mul_byte")  //  the optimized routines should have been checked earlier
+            "/" -> asmgen.out(if(types==DataType.UBYTE) "  jsr  prog8_lib.idiv_ub" else "  jsr  prog8_lib.idiv_b")
+            "%" -> {
+                if(types==DataType.BYTE)
+                    throw AssemblyError("remainder of signed integers is not properly defined/implemented, use unsigned instead")
+                asmgen.out("  jsr prog8_lib.remainder_ub")
+            }
+            "+" -> asmgen.out("""
+                lda  P8ESTACK_LO+2,x
+                clc
+                adc  P8ESTACK_LO+1,x
+                inx
+                sta  P8ESTACK_LO+1,x
+                """)
+            "-" -> asmgen.out("""
+                lda  P8ESTACK_LO+2,x
+                sec
+                sbc  P8ESTACK_LO+1,x
+                inx
+                sta  P8ESTACK_LO+1,x
+                """)
+            "<<" -> asmgen.out("  jsr  prog8_lib.shiftleft_b")
+            ">>" -> asmgen.out("  jsr  prog8_lib.shiftright_b")
+            "<" -> asmgen.out(if(types==DataType.UBYTE) "  jsr  prog8_lib.less_ub" else "  jsr  prog8_lib.less_b")
+            ">" -> asmgen.out(if(types==DataType.UBYTE) "  jsr  prog8_lib.greater_ub" else "  jsr  prog8_lib.greater_b")
+            "<=" -> asmgen.out(if(types==DataType.UBYTE) "  jsr  prog8_lib.lesseq_ub" else "  jsr  prog8_lib.lesseq_b")
+            ">=" -> asmgen.out(if(types==DataType.UBYTE) "  jsr  prog8_lib.greatereq_ub" else "  jsr  prog8_lib.greatereq_b")
+            "==" -> asmgen.out("  jsr  prog8_lib.equal_b")
+            "!=" -> asmgen.out("  jsr  prog8_lib.notequal_b")
+            "&" -> asmgen.out("  jsr  prog8_lib.bitand_b")
+            "^" -> asmgen.out("  jsr  prog8_lib.bitxor_b")
+            "|" -> asmgen.out("  jsr  prog8_lib.bitor_b")
+            "and" -> asmgen.out("  jsr  prog8_lib.and_b")
+            "or" -> asmgen.out("  jsr  prog8_lib.or_b")
+            "xor" -> asmgen.out("  jsr  prog8_lib.xor_b")
+            else -> throw AssemblyError("invalid operator $operator")
+        }
+    }
+
+    private fun translateBinaryOperatorWords(operator: String, types: DataType) {
+        when(operator) {
+            "**" -> throw AssemblyError("** operator requires floats")
+            "*" -> asmgen.out("  jsr  prog8_lib.mul_word")
+            "/" -> asmgen.out(if(types==DataType.UWORD) "  jsr  prog8_lib.idiv_uw" else "  jsr  prog8_lib.idiv_w")
+            "%" -> {
+                if(types==DataType.WORD)
+                    throw AssemblyError("remainder of signed integers is not properly defined/implemented, use unsigned instead")
+                asmgen.out("  jsr prog8_lib.remainder_uw")
+            }
+            "+" -> asmgen.out("  jsr  prog8_lib.add_w")
+            "-" -> asmgen.out("  jsr  prog8_lib.sub_w")
+            "<<" -> throw AssemblyError("<< should not operate via stack")
+            ">>" -> throw AssemblyError(">> should not operate via stack")
+            "<" -> asmgen.out(if(types==DataType.UWORD) "  jsr  prog8_lib.less_uw" else "  jsr  prog8_lib.less_w")
+            ">" -> asmgen.out(if(types==DataType.UWORD) "  jsr  prog8_lib.greater_uw" else "  jsr  prog8_lib.greater_w")
+            "<=" -> asmgen.out(if(types==DataType.UWORD) "  jsr  prog8_lib.lesseq_uw" else "  jsr  prog8_lib.lesseq_w")
+            ">=" -> asmgen.out(if(types==DataType.UWORD) "  jsr  prog8_lib.greatereq_uw" else "  jsr  prog8_lib.greatereq_w")
+            "==" -> asmgen.out("  jsr  prog8_lib.equal_w")
+            "!=" -> asmgen.out("  jsr  prog8_lib.notequal_w")
+            "&" -> asmgen.out("  jsr  prog8_lib.bitand_w")
+            "^" -> asmgen.out("  jsr  prog8_lib.bitxor_w")
+            "|" -> asmgen.out("  jsr  prog8_lib.bitor_w")
+            "and" -> asmgen.out("  jsr  prog8_lib.and_w")
+            "or" -> asmgen.out("  jsr  prog8_lib.or_w")
+            "xor" -> asmgen.out("  jsr  prog8_lib.xor_w")
+            else -> throw AssemblyError("invalid operator $operator")
+        }
+    }
+
+    private fun translateBinaryOperatorFloats(operator: String) {
+        when(operator) {
+            "**" -> asmgen.out(" jsr  c64flt.pow_f")
+            "*" -> asmgen.out("  jsr  c64flt.mul_f")
+            "/" -> asmgen.out("  jsr  c64flt.div_f")
+            "+" -> asmgen.out("  jsr  c64flt.add_f")
+            "-" -> asmgen.out("  jsr  c64flt.sub_f")
+            "<" -> asmgen.out("  jsr  c64flt.less_f")
+            ">" -> asmgen.out("  jsr  c64flt.greater_f")
+            "<=" -> asmgen.out("  jsr  c64flt.lesseq_f")
+            ">=" -> asmgen.out("  jsr  c64flt.greatereq_f")
+            "==" -> asmgen.out("  jsr  c64flt.equal_f")
+            "!=" -> asmgen.out("  jsr  c64flt.notequal_f")
+            "%", "<<", ">>", "&", "^", "|", "and", "or", "xor" -> throw AssemblyError("requires integer datatype")
+            else -> throw AssemblyError("invalid operator $operator")
+        }
+    }
+}

compiler/src/prog8/compiler/target/c64/codegen/ForLoopsAsmGen.kt

@@ -0,0 +1,618 @@
+package prog8.compiler.target.c64.codegen
+
+import prog8.ast.Program
+import prog8.ast.base.DataType
+import prog8.ast.expressions.IdentifierReference
+import prog8.ast.expressions.RangeExpr
+import prog8.ast.statements.ForLoop
+import prog8.compiler.AssemblyError
+import prog8.compiler.target.c64.codegen.assignment.AsmAssignSource
+import prog8.compiler.target.c64.codegen.assignment.AsmAssignTarget
+import prog8.compiler.target.c64.codegen.assignment.AsmAssignment
+import prog8.compiler.target.c64.codegen.assignment.TargetStorageKind
+import prog8.compiler.toHex
+import kotlin.math.absoluteValue
+
+internal class ForLoopsAsmGen(private val program: Program, private val asmgen: AsmGen) {
+
+    internal fun translate(stmt: ForLoop) {
+        val iterableDt = stmt.iterable.inferType(program)
+        if(!iterableDt.isKnown)
+            throw AssemblyError("can't determine iterable dt")
+        when(stmt.iterable) {
+            is RangeExpr -> {
+                val range = (stmt.iterable as RangeExpr).toConstantIntegerRange()
+                if(range==null) {
+                    translateForOverNonconstRange(stmt, iterableDt.typeOrElse(DataType.STRUCT), stmt.iterable as RangeExpr)
+                } else {
+                    translateForOverConstRange(stmt, iterableDt.typeOrElse(DataType.STRUCT), range)
+                }
+            }
+            is IdentifierReference -> {
+                translateForOverIterableVar(stmt, iterableDt.typeOrElse(DataType.STRUCT), stmt.iterable as IdentifierReference)
+            }
+            else -> throw AssemblyError("can't iterate over ${stmt.iterable.javaClass} - should have been replaced by a variable")
+        }
+    }
+
+    private fun translateForOverNonconstRange(stmt: ForLoop, iterableDt: DataType, range: RangeExpr) {
+        val loopLabel = asmgen.makeLabel("for_loop")
+        val endLabel = asmgen.makeLabel("for_end")
+        val modifiedLabel = asmgen.makeLabel("for_modified")
+        val modifiedLabel2 = asmgen.makeLabel("for_modifiedb")
+        asmgen.loopEndLabels.push(endLabel)
+        val stepsize=range.step.constValue(program)!!.number.toInt()
+        when(iterableDt) {
+            DataType.ARRAY_B, DataType.ARRAY_UB -> {
+                if (stepsize==1 || stepsize==-1) {
+
+                    // bytes, step 1 or -1
+
+                    val incdec = if(stepsize==1) "inc" else "dec"
+                    // loop over byte range via loopvar
+                    val varname = asmgen.asmVariableName(stmt.loopVar)
+                    asmgen.translateExpression(range.to)
+                    asmgen.translateExpression(range.from)
+                    asmgen.out("""
+                inx
+                lda  P8ESTACK_LO,x
+                sta  $varname
+                lda  P8ESTACK_LO+1,x
+                sta  $modifiedLabel+1
+$loopLabel""")
+                        asmgen.translate(stmt.body)
+                        asmgen.out("""
+                lda  $varname
+$modifiedLabel  cmp  #0         ; modified 
+                beq  $endLabel
+                $incdec  $varname
+                jmp  $loopLabel
+$endLabel       inx""")
+
+                } else {
+
+                    // bytes, step >= 2 or <= -2
+
+                    // loop over byte range via loopvar
+                    val varname = asmgen.asmVariableName(stmt.loopVar)
+                    asmgen.translateExpression(range.to)
+                    asmgen.translateExpression(range.from)
+                    asmgen.out("""
+                inx
+                lda  P8ESTACK_LO,x
+                sta  $varname
+                lda  P8ESTACK_LO+1,x
+                sta  $modifiedLabel+1
+$loopLabel""")
+                    asmgen.translate(stmt.body)
+                    asmgen.out("""
+                lda  $varname""")
+                    if(stepsize>0) {
+                        asmgen.out("""
+                clc
+                adc  #$stepsize
+                sta  $varname
+$modifiedLabel  cmp  #0    ; modified
+                bcc  $loopLabel
+                beq  $loopLabel""")
+                    } else {
+                        asmgen.out("""
+                sec
+                sbc  #${stepsize.absoluteValue}
+                sta  $varname
+$modifiedLabel  cmp  #0     ; modified 
+                bcs  $loopLabel""")
+                    }
+                    asmgen.out("""
+$endLabel       inx""")
+                }
+            }
+            DataType.ARRAY_W, DataType.ARRAY_UW -> {
+                when {
+
+                    // words, step 1 or -1
+
+                    stepsize == 1 || stepsize == -1 -> {
+                        asmgen.translateExpression(range.to)
+                        assignLoopvar(stmt, range)
+                        val varname = asmgen.asmVariableName(stmt.loopVar)
+                        asmgen.out("""
+                            lda  P8ESTACK_HI+1,x
+                            sta  $modifiedLabel+1
+                            lda  P8ESTACK_LO+1,x
+                            sta  $modifiedLabel2+1
+$loopLabel""")
+                        asmgen.translate(stmt.body)
+                        asmgen.out("""
+                lda  $varname+1
+$modifiedLabel  cmp  #0    ; modified 
+                bne  +
+                lda  $varname
+$modifiedLabel2 cmp  #0    ; modified 
+                beq  $endLabel""")
+                        if(stepsize==1) {
+                            asmgen.out("""
++               inc  $varname
+                bne  $loopLabel
+                inc  $varname+1
+                jmp  $loopLabel
+                            """)
+                        } else {
+                            asmgen.out("""
++               lda  $varname
+                bne  +
+                dec  $varname+1
++               dec  $varname
+                jmp  $loopLabel""")
+                        }
+                        asmgen.out(endLabel)
+                        asmgen.out(" inx")
+                    }
+                    stepsize > 0 -> {
+
+                        // (u)words, step >= 2
+                        asmgen.translateExpression(range.to)
+                        asmgen.out("""
+                            lda  P8ESTACK_HI+1,x
+                            sta  $modifiedLabel+1
+                            lda  P8ESTACK_LO+1,x
+                            sta  $modifiedLabel2+1
+                        """)
+                        assignLoopvar(stmt, range)
+                        val varname = asmgen.asmVariableName(stmt.loopVar)
+                        asmgen.out(loopLabel)
+                        asmgen.translate(stmt.body)
+
+                        if (iterableDt == DataType.ARRAY_UW) {
+                            asmgen.out("""
+                lda  $varname
+                clc
+                adc  #<$stepsize
+                sta  $varname
+                lda  $varname+1
+                adc  #>$stepsize
+                sta  $varname+1
+$modifiedLabel  cmp  #0     ; modified
+                bcc  $loopLabel
+                bne  $endLabel
+$modifiedLabel2 lda  #0     ; modified
+                cmp  $varname
+                bcc  $endLabel
+                bcs  $loopLabel
+$endLabel       inx""")
+                        } else {
+                            asmgen.out("""
+                lda  $varname
+                clc
+                adc  #<$stepsize
+                sta  $varname
+                lda  $varname+1
+                adc  #>$stepsize
+                sta  $varname+1
+$modifiedLabel2 lda  #0   ; modified
+                cmp  $varname
+$modifiedLabel  lda  #0   ; modified
+                sbc  $varname+1
+                bvc  +
+                eor  #$80
++               bpl  $loopLabel                
+$endLabel       inx""")
+                        }
+                    }
+                    else -> {
+
+                        // (u)words, step <= -2
+                        asmgen.translateExpression(range.to)
+                        asmgen.out("""
+                            lda  P8ESTACK_HI+1,x
+                            sta  $modifiedLabel+1
+                            lda  P8ESTACK_LO+1,x
+                            sta  $modifiedLabel2+1
+                        """)
+                        assignLoopvar(stmt, range)
+                        val varname = asmgen.asmVariableName(stmt.loopVar)
+                        asmgen.out(loopLabel)
+                        asmgen.translate(stmt.body)
+
+                        if(iterableDt==DataType.ARRAY_UW) {
+                            asmgen.out("""
+                lda  $varname
+                sec
+                sbc  #<${stepsize.absoluteValue}
+                sta  $varname
+                lda  $varname+1
+                sbc  #>${stepsize.absoluteValue}
+                sta  $varname+1
+$modifiedLabel  cmp  #0    ; modified                
+                bcc  $endLabel
+                bne  $loopLabel
+                lda  $varname
+$modifiedLabel2 cmp  #0    ; modified 
+                bcs  $loopLabel
+$endLabel       inx""")
+                        } else {
+                            asmgen.out("""
+                lda  $varname
+                sec
+                sbc  #<${stepsize.absoluteValue}
+                sta  $varname
+                pha
+                lda  $varname+1
+                sbc  #>${stepsize.absoluteValue}
+                sta  $varname+1
+                pla
+$modifiedLabel2 cmp  #0    ; modified 
+                lda  $varname+1
+$modifiedLabel  sbc  #0    ; modified
+                bvc  +
+                eor  #$80
++               bpl  $loopLabel                
+$endLabel       inx""")
+                        }
+                    }
+                }
+            }
+            else -> throw AssemblyError("range expression can only be byte or word")
+        }
+
+        asmgen.loopEndLabels.pop()
+    }
+
+    private fun assignLoopvar(stmt: ForLoop, range: RangeExpr) {
+        val target = AsmAssignTarget(TargetStorageKind.VARIABLE, program, asmgen, stmt.loopVarDt(program).typeOrElse(DataType.STRUCT), variable=stmt.loopVar)
+        val src = AsmAssignSource.fromAstSource(range.from, program).adjustDataTypeToTarget(target)
+        val assign = AsmAssignment(src, target, false, range.position)
+        asmgen.translateNormalAssignment(assign)
+    }
+
+    private fun translateForOverIterableVar(stmt: ForLoop, iterableDt: DataType, ident: IdentifierReference) {
+        val loopLabel = asmgen.makeLabel("for_loop")
+        val endLabel = asmgen.makeLabel("for_end")
+        asmgen.loopEndLabels.push(endLabel)
+        val iterableName = asmgen.asmVariableName(ident)
+        val decl = ident.targetVarDecl(program.namespace)!!
+        when(iterableDt) {
+            DataType.STR -> {
+                asmgen.out("""
+                    lda  #<$iterableName
+                    ldy  #>$iterableName
+                    sta  $loopLabel+1
+                    sty  $loopLabel+2
+$loopLabel          lda  ${65535.toHex()}       ; modified
+                    beq  $endLabel
+                    sta  ${asmgen.asmVariableName(stmt.loopVar)}""")
+                asmgen.translate(stmt.body)
+                asmgen.out("""
+                    inc  $loopLabel+1
+                    bne  $loopLabel
+                    inc  $loopLabel+2
+                    bne  $loopLabel
+$endLabel""")
+            }
+            DataType.ARRAY_UB, DataType.ARRAY_B -> {
+                val length = decl.arraysize!!.constIndex()!!
+                val indexVar = asmgen.makeLabel("for_index")
+                asmgen.out("""
+                    ldy  #0
+$loopLabel          sty  $indexVar
+                    lda  $iterableName,y
+                    sta  ${asmgen.asmVariableName(stmt.loopVar)}""")
+                asmgen.translate(stmt.body)
+                if(length<=255) {
+                    asmgen.out("""
+                        ldy  $indexVar
+                        iny
+                        cpy  #$length
+                        beq  $endLabel
+                        bne  $loopLabel""")
+                } else {
+                    // length is 256
+                    asmgen.out("""
+                        ldy  $indexVar
+                        iny
+                        bne  $loopLabel
+                        beq  $endLabel""")
+                }
+                if(length>=16 && asmgen.zeropage.available() > 0) {
+                    // allocate index var on ZP
+                    val zpAddr = asmgen.zeropage.allocate(indexVar, DataType.UBYTE, stmt.position, asmgen.errors)
+                    asmgen.out("""$indexVar = $zpAddr  ; auto zp UBYTE""")
+                } else {
+                    asmgen.out("""
+$indexVar           .byte  0""")
+                }
+                asmgen.out(endLabel)
+            }
+            DataType.ARRAY_W, DataType.ARRAY_UW -> {
+                val length = decl.arraysize!!.constIndex()!! * 2
+                val indexVar = asmgen.makeLabel("for_index")
+                val loopvarName = asmgen.asmVariableName(stmt.loopVar)
+                asmgen.out("""
+                    ldy  #0
+$loopLabel          sty  $indexVar
+                    lda  $iterableName,y
+                    sta  $loopvarName
+                    lda  $iterableName+1,y
+                    sta  $loopvarName+1""")
+                asmgen.translate(stmt.body)
+                if(length<=127) {
+                    asmgen.out("""
+                        ldy  $indexVar
+                        iny
+                        iny
+                        cpy  #$length
+                        beq  $endLabel
+                        bne  $loopLabel""")
+                } else {
+                    // length is 128 words, 256 bytes
+                    asmgen.out("""
+                        ldy  $indexVar
+                        iny
+                        iny
+                        bne  $loopLabel
+                        beq  $endLabel""")
+                }
+                if(length>=16 && asmgen.zeropage.available() > 0) {
+                    // allocate index var on ZP
+                    val zpAddr = asmgen.zeropage.allocate(indexVar, DataType.UBYTE, stmt.position, asmgen.errors)
+                    asmgen.out("""$indexVar = $zpAddr  ; auto zp UBYTE""")
+                } else {
+                    asmgen.out("""
+$indexVar           .byte  0""")
+                }
+                asmgen.out(endLabel)
+            }
+            DataType.ARRAY_F -> {
+                throw AssemblyError("for loop with floating point variables is not supported")
+            }
+            else -> throw AssemblyError("can't iterate over $iterableDt")
+        }
+        asmgen.loopEndLabels.pop()
+    }
+
+    private fun translateForOverConstRange(stmt: ForLoop, iterableDt: DataType, range: IntProgression) {
+        if (range.isEmpty() || range.step==0)
+            throw AssemblyError("empty range or step 0")
+        if(iterableDt==DataType.ARRAY_B || iterableDt==DataType.ARRAY_UB) {
+            if(range.step==1 && range.last>range.first) return translateForSimpleByteRangeAsc(stmt, range)
+            if(range.step==-1 && range.last<range.first) return translateForSimpleByteRangeDesc(stmt, range)
+        }
+        else if(iterableDt==DataType.ARRAY_W || iterableDt==DataType.ARRAY_UW) {
+            if(range.step==1 && range.last>range.first) return translateForSimpleWordRangeAsc(stmt, range)
+            if(range.step==-1 && range.last<range.first) return translateForSimpleWordRangeDesc(stmt, range)
+        }
+
+        // not one of the easy cases, generate more complex code...
+        val loopLabel = asmgen.makeLabel("for_loop")
+        val endLabel = asmgen.makeLabel("for_end")
+        asmgen.loopEndLabels.push(endLabel)
+        when(iterableDt) {
+            DataType.ARRAY_B, DataType.ARRAY_UB -> {
+                // loop over byte range via loopvar, step >= 2 or <= -2
+                val varname = asmgen.asmVariableName(stmt.loopVar)
+                asmgen.out("""
+                            lda  #${range.first}
+                            sta  $varname
+$loopLabel""")
+                asmgen.translate(stmt.body)
+                when (range.step) {
+                    0, 1, -1 -> {
+                        throw AssemblyError("step 0, 1 and -1 should have been handled specifically  $stmt")
+                    }
+                    2 -> {
+                        if(range.last==255) {
+                            asmgen.out("""
+                                inc  $varname
+                                beq  $endLabel
+                                inc  $varname
+                                bne  $loopLabel""")
+                        } else {
+                            asmgen.out("""
+                                lda  $varname
+                                cmp  #${range.last}
+                                beq  $endLabel
+                                inc  $varname
+                                inc  $varname
+                                jmp  $loopLabel""")
+                        }
+                    }
+                    -2 -> {
+                        when (range.last) {
+                            0 -> asmgen.out("""
+                                lda  $varname
+                                beq  $endLabel
+                                dec  $varname
+                                dec  $varname
+                                jmp  $loopLabel""")
+                            1 -> asmgen.out("""
+                                dec  $varname
+                                beq  $endLabel
+                                dec  $varname
+                                bne  $loopLabel""")
+                            else -> asmgen.out("""
+                                lda  $varname
+                                cmp  #${range.last}
+                                beq  $endLabel
+                                dec  $varname
+                                dec  $varname
+                                jmp  $loopLabel""")
+                        }
+                    }
+                    else -> {
+                        // step <= -3 or >= 3
+                        asmgen.out("""
+                            lda  $varname
+                            cmp  #${range.last}
+                            beq  $endLabel
+                            clc
+                            adc  #${range.step}
+                            sta  $varname
+                            jmp  $loopLabel""")
+                    }
+                }
+                asmgen.out(endLabel)
+            }
+            DataType.ARRAY_W, DataType.ARRAY_UW -> {
+                // loop over word range via loopvar, step >= 2 or <= -2
+                val varname = asmgen.asmVariableName(stmt.loopVar)
+                when (range.step) {
+                    0, 1, -1 -> {
+                        throw AssemblyError("step 0, 1 and -1 should have been handled specifically  $stmt")
+                    }
+                    else -> {
+                        // word, step >= 2 or <= -2
+                        // note: range.last has already been adjusted by kotlin itself to actually be the last value of the sequence
+                        asmgen.out("""
+                            lda  #<${range.first}
+                            ldy  #>${range.first}
+                            sta  $varname
+                            sty  $varname+1
+$loopLabel""")
+                        asmgen.translate(stmt.body)
+                        asmgen.out("""
+                            lda  $varname
+                            cmp  #<${range.last}
+                            bne  +
+                            lda  $varname+1
+                            cmp  #>${range.last}
+                            bne  +
+                            beq  $endLabel
++                           lda  $varname
+                            clc
+                            adc  #<${range.step}
+                            sta  $varname
+                            lda  $varname+1
+                            adc  #>${range.step}
+                            sta  $varname+1
+                            jmp  $loopLabel
+$endLabel""")
+                    }
+                }
+            }
+            else -> throw AssemblyError("range expression can only be byte or word")
+        }
+        asmgen.loopEndLabels.pop()
+    }
+
+    private fun translateForSimpleByteRangeAsc(stmt: ForLoop, range: IntProgression) {
+        val loopLabel = asmgen.makeLabel("for_loop")
+        val endLabel = asmgen.makeLabel("for_end")
+        asmgen.loopEndLabels.push(endLabel)
+        val varname = asmgen.asmVariableName(stmt.loopVar)
+        asmgen.out("""
+                lda  #${range.first}
+                sta  $varname
+$loopLabel""")
+        asmgen.translate(stmt.body)
+        if (range.last == 255) {
+            asmgen.out("""
+                inc  $varname
+                bne  $loopLabel
+$endLabel""")
+        } else {
+            asmgen.out("""
+                lda  $varname
+                cmp  #${range.last}
+                beq  $endLabel
+                inc  $varname
+                jmp  $loopLabel
+$endLabel""")
+        }
+        asmgen.loopEndLabels.pop()
+    }
+
+    private fun translateForSimpleByteRangeDesc(stmt: ForLoop, range: IntProgression) {
+        val loopLabel = asmgen.makeLabel("for_loop")
+        val endLabel = asmgen.makeLabel("for_end")
+        asmgen.loopEndLabels.push(endLabel)
+        val varname = asmgen.asmVariableName(stmt.loopVar)
+        asmgen.out("""
+                    lda  #${range.first}
+                    sta  $varname
+$loopLabel""")
+        asmgen.translate(stmt.body)
+        when (range.last) {
+            0 -> {
+                asmgen.out("""
+                    lda  $varname
+                    beq  $endLabel
+                    dec  $varname
+                    jmp  $loopLabel
+$endLabel""")
+            }
+            1 -> {
+                asmgen.out("""
+                    dec  $varname
+                    jmp  $loopLabel
+$endLabel""")
+            }
+            else -> {
+                asmgen.out("""
+                    lda  $varname
+                    cmp  #${range.last}
+                    beq  $endLabel
+                    dec  $varname
+                    jmp  $loopLabel
+$endLabel""")
+            }
+        }
+        asmgen.loopEndLabels.pop()
+    }
+
+    private fun translateForSimpleWordRangeAsc(stmt: ForLoop, range: IntProgression) {
+        val loopLabel = asmgen.makeLabel("for_loop")
+        val endLabel = asmgen.makeLabel("for_end")
+        asmgen.loopEndLabels.push(endLabel)
+        val varname = asmgen.asmVariableName(stmt.loopVar)
+        asmgen.out("""
+            lda  #<${range.first}
+            ldy  #>${range.first}
+            sta  $varname
+            sty  $varname+1
+$loopLabel""")
+        asmgen.translate(stmt.body)
+        asmgen.out("""
+            lda  $varname
+            cmp  #<${range.last}
+            bne  +
+            lda  $varname+1
+            cmp  #>${range.last}
+            bne  +
+            beq  $endLabel
++           inc  $varname
+            bne  $loopLabel
+            inc  $varname+1
+            jmp  $loopLabel
+$endLabel""")
+        asmgen.loopEndLabels.pop()
+    }
+
+    private fun translateForSimpleWordRangeDesc(stmt: ForLoop, range: IntProgression) {
+        val loopLabel = asmgen.makeLabel("for_loop")
+        val endLabel = asmgen.makeLabel("for_end")
+        asmgen.loopEndLabels.push(endLabel)
+        val varname = asmgen.asmVariableName(stmt.loopVar)
+        asmgen.out("""
+            lda  #<${range.first}
+            ldy  #>${range.first}
+            sta  $varname
+            sty  $varname+1
+$loopLabel""")
+        asmgen.translate(stmt.body)
+        asmgen.out("""
+            lda  $varname
+            cmp  #<${range.last}
+            bne  +
+            lda  $varname+1
+            cmp  #>${range.last}
+            bne  +
+            beq  $endLabel
++           lda  $varname
+            bne  +
+            dec  $varname+1
++           dec  $varname
+            jmp  $loopLabel
+$endLabel""")
+        asmgen.loopEndLabels.pop()
+    }
+}

compiler/src/prog8/compiler/target/c64/codegen/FunctionCallAsmGen.kt

@@ -0,0 +1,202 @@
+package prog8.compiler.target.c64.codegen
+
+import prog8.ast.IFunctionCall
+import prog8.ast.Program
+import prog8.ast.base.*
+import prog8.ast.expressions.*
+import prog8.ast.statements.Subroutine
+import prog8.ast.statements.SubroutineParameter
+import prog8.compiler.AssemblyError
+import prog8.compiler.target.c64.codegen.assignment.*
+
+
+internal class FunctionCallAsmGen(private val program: Program, private val asmgen: AsmGen) {
+
+    internal fun translateFunctionCall(stmt: IFunctionCall) {
+        // output the code to setup the parameters and perform the actual call
+        // does NOT output the code to deal with the result values!
+        val sub = stmt.target.targetSubroutine(program.namespace) ?: throw AssemblyError("undefined subroutine ${stmt.target}")
+        val saveX = CpuRegister.X in sub.asmClobbers || sub.regXasResult()
+        if(saveX)
+            asmgen.out("  stx  P8ZP_SCRATCH_REG_X")        // we only save X for now (required! is the eval stack pointer), screw A and Y...
+
+        val subName = asmgen.asmSymbolName(stmt.target)
+        if(stmt.args.isNotEmpty()) {
+            if(sub.asmParameterRegisters.isEmpty()) {
+                // via variables
+                for(arg in sub.parameters.withIndex().zip(stmt.args)) {
+                    argumentViaVariable(sub, arg.first, arg.second)
+                }
+            } else {
+                // via registers
+                if(sub.parameters.size==1) {
+                    // just a single parameter, no risk of clobbering registers
+                    argumentViaRegister(sub, sub.parameters.withIndex().single(), stmt.args[0])
+                } else {
+                    // multiple register arguments, risk of register clobbering.
+                    // evaluate arguments onto the stack, and load the registers from the evaluated values on the stack.
+                    when {
+                        stmt.args.all {it is AddressOf ||
+                                it is NumericLiteralValue ||
+                                it is StringLiteralValue ||
+                                it is ArrayLiteralValue ||
+                                it is IdentifierReference} -> {
+                            // no risk of clobbering for these simple argument types. Optimize the register loading.
+                            for(arg in sub.parameters.withIndex().zip(stmt.args)) {
+                                argumentViaRegister(sub, arg.first, arg.second)
+                            }
+                        }
+                        else -> {
+                            // Risk of clobbering due to complex expression args. Work via the stack.
+                            registerArgsViaStackEvaluation(stmt, sub)
+                        }
+                    }
+                }
+            }
+        }
+        asmgen.out("  jsr  $subName")
+
+        if(saveX)
+            asmgen.out("  ldx  P8ZP_SCRATCH_REG_X")        // restore X again
+    }
+
+    private fun registerArgsViaStackEvaluation(stmt: IFunctionCall, sub: Subroutine) {
+        // this is called when one or more of the arguments are 'complex' and
+        // cannot be assigned to a register easily or risk clobbering other registers.
+        for (arg in stmt.args.reversed())
+            asmgen.translateExpression(arg)
+        for (regparam in sub.asmParameterRegisters) {
+            when {
+                regparam.statusflag==Statusflag.Pc -> {
+                    asmgen.out("""
+                        inx
+                        pha
+                        lda  P8ESTACK_LO,x
+                        beq  +
+                        sec  
+                        bcs  ++
++                       clc
++                       pla""")
+                }
+                regparam.statusflag!=null -> {
+                    throw AssemblyError("can only use Carry as status flag parameter")
+                }
+                regparam.registerOrPair!=null -> {
+                    val tgt = AsmAssignTarget.fromRegisters(regparam.registerOrPair, program, asmgen)
+                    val source = AsmAssignSource(SourceStorageKind.STACK, program, tgt.datatype)
+                    val asgn = AsmAssignment(source, tgt, false, Position.DUMMY)
+                    asmgen.translateNormalAssignment(asgn)
+                }
+                else -> {}
+            }
+        }
+    }
+
+    private fun argumentViaVariable(sub: Subroutine, parameter: IndexedValue<SubroutineParameter>, value: Expression) {
+        // pass parameter via a regular variable (not via registers)
+        val valueIDt = value.inferType(program)
+        if(!valueIDt.isKnown)
+            throw AssemblyError("arg type unknown")
+        val valueDt = valueIDt.typeOrElse(DataType.STRUCT)
+        if(!isArgumentTypeCompatible(valueDt, parameter.value.type))
+            throw AssemblyError("argument type incompatible")
+
+        val scopedParamVar = (sub.scopedname+"."+parameter.value.name).split(".")
+        val identifier = IdentifierReference(scopedParamVar, sub.position)
+        identifier.linkParents(value.parent)
+        val tgt = AsmAssignTarget(TargetStorageKind.VARIABLE, program, asmgen, parameter.value.type, variable = identifier)
+        val source = AsmAssignSource.fromAstSource(value, program).adjustDataTypeToTarget(tgt)
+        val asgn = AsmAssignment(source, tgt, false, Position.DUMMY)
+        asmgen.translateNormalAssignment(asgn)
+    }
+
+    private fun argumentViaRegister(sub: Subroutine, parameter: IndexedValue<SubroutineParameter>, value: Expression) {
+        // pass argument via a register parameter
+        val valueIDt = value.inferType(program)
+        if(!valueIDt.isKnown)
+            throw AssemblyError("arg type unknown")
+        val valueDt = valueIDt.typeOrElse(DataType.STRUCT)
+        if(!isArgumentTypeCompatible(valueDt, parameter.value.type))
+            throw AssemblyError("argument type incompatible")
+
+        val paramRegister = sub.asmParameterRegisters[parameter.index]
+        val statusflag = paramRegister.statusflag
+        val register = paramRegister.registerOrPair
+        val stack = paramRegister.stack
+        when {
+            stack -> {
+                // push arg onto the stack
+                // note: argument order is reversed (first argument will be deepest on the stack)
+                asmgen.translateExpression(value)
+            }
+            statusflag!=null -> {
+                if (statusflag == Statusflag.Pc) {
+                    // this param needs to be set last, right before the jsr
+                    // for now, this is already enforced on the subroutine definition by the Ast Checker
+                    when(value) {
+                        is NumericLiteralValue -> {
+                            val carrySet = value.number.toInt() != 0
+                            asmgen.out(if(carrySet) "  sec" else "  clc")
+                        }
+                        is IdentifierReference -> {
+                            val sourceName = asmgen.asmVariableName(value)
+                            asmgen.out("""
+            pha
+            lda  $sourceName
+            beq  +
+            sec  
+            bcs  ++
++           clc
++           pla
+""")
+                        }
+                        else -> {
+                            asmgen.translateExpression(value)
+                            asmgen.out("""
+            inx
+            pha
+            lda  P8ESTACK_LO,x
+            beq  +
+            sec  
+            bcs  ++
++           clc
++           pla
+""")
+                        }
+                    }
+                }
+                else throw AssemblyError("can only use Carry as status flag parameter")
+            }
+            else -> {
+                // via register or register pair
+                val target = AsmAssignTarget.fromRegisters(register!!, program, asmgen)
+                val src = if(valueDt in PassByReferenceDatatypes) {
+                    val addr = AddressOf(value as IdentifierReference, Position.DUMMY)
+                    AsmAssignSource.fromAstSource(addr, program).adjustDataTypeToTarget(target)
+                } else {
+                    AsmAssignSource.fromAstSource(value, program).adjustDataTypeToTarget(target)
+                }
+
+                asmgen.translateNormalAssignment(AsmAssignment(src, target, false, Position.DUMMY))
+            }
+        }
+    }
+
+    private fun isArgumentTypeCompatible(argType: DataType, paramType: DataType): Boolean {
+        if(argType isAssignableTo paramType)
+            return true
+        if(argType in ByteDatatypes && paramType in ByteDatatypes)
+            return true
+        if(argType in WordDatatypes && paramType in WordDatatypes)
+            return true
+
+        // we have a special rule for some types.
+        // strings are assignable to UWORD, for example, and vice versa
+        if(argType==DataType.STR && paramType==DataType.UWORD)
+            return true
+        if(argType==DataType.UWORD && paramType == DataType.STR)
+            return true
+
+        return false
+    }
+}

compiler/src/prog8/compiler/target/c64/codegen/PostIncrDecrAsmGen.kt

@@ -0,0 +1,134 @@
+package prog8.compiler.target.c64.codegen
+
+import prog8.ast.Program
+import prog8.ast.base.*
+import prog8.ast.expressions.IdentifierReference
+import prog8.ast.expressions.NumericLiteralValue
+import prog8.ast.statements.PostIncrDecr
+import prog8.compiler.AssemblyError
+import prog8.compiler.toHex
+
+
+internal class PostIncrDecrAsmGen(private val program: Program, private val asmgen: AsmGen) {
+    internal fun translate(stmt: PostIncrDecr) {
+        val incr = stmt.operator=="++"
+        val targetIdent = stmt.target.identifier
+        val targetMemory = stmt.target.memoryAddress
+        val targetArrayIdx = stmt.target.arrayindexed
+        when {
+            targetIdent!=null -> {
+                val what = asmgen.asmVariableName(targetIdent)
+                when (stmt.target.inferType(program, stmt).typeOrElse(DataType.STRUCT)) {
+                    in ByteDatatypes -> asmgen.out(if (incr) "  inc  $what" else "  dec  $what")
+                    in WordDatatypes -> {
+                        if(incr)
+                            asmgen.out(" inc  $what |  bne  + |  inc  $what+1 |+")
+                        else
+                            asmgen.out("""
+        lda  $what
+        bne  +
+        dec  $what+1
++       dec  $what 
+""")
+                    }
+                    DataType.FLOAT -> {
+                        asmgen.out("  lda  #<$what |  ldy  #>$what")
+                        asmgen.out(if(incr) "  jsr  c64flt.inc_var_f" else "  jsr  c64flt.dec_var_f")
+                    }
+                    else -> throw AssemblyError("need numeric type")
+                }
+            }
+            targetMemory!=null -> {
+                when (val addressExpr = targetMemory.addressExpression) {
+                    is NumericLiteralValue -> {
+                        val what = addressExpr.number.toHex()
+                        asmgen.out(if(incr) "  inc  $what" else "  dec  $what")
+                    }
+                    is IdentifierReference -> {
+                        val what = asmgen.asmVariableName(addressExpr)
+                        asmgen.out("  lda  $what |  sta  (+) +1 |  lda  $what+1 |  sta  (+) +2")
+                        if(incr)
+                            asmgen.out("+\tinc  ${'$'}ffff\t; modified")
+                        else
+                            asmgen.out("+\tdec  ${'$'}ffff\t; modified")
+                    }
+                    else -> {
+                        asmgen.translateExpression(addressExpr)
+                        asmgen.out("""
+                            inx
+                            lda  P8ESTACK_LO,x
+                            sta  (+) + 1
+                            lda  P8ESTACK_HI,x
+                            sta  (+) + 2
+                        """)
+                        if(incr)
+                            asmgen.out("+\tinc  ${'$'}ffff\t; modified")
+                        else
+                            asmgen.out("+\tdec  ${'$'}ffff\t; modified")
+                    }
+                }
+            }
+            targetArrayIdx!=null -> {
+                val index = targetArrayIdx.arrayspec.index
+                val asmArrayvarname = asmgen.asmVariableName(targetArrayIdx.identifier)
+                val elementDt = targetArrayIdx.inferType(program).typeOrElse(DataType.STRUCT)
+                when(index) {
+                    is NumericLiteralValue -> {
+                        val indexValue = index.number.toInt() * elementDt.memorySize()
+                        when(elementDt) {
+                            in ByteDatatypes -> asmgen.out(if (incr) "  inc  $asmArrayvarname+$indexValue" else "  dec  $asmArrayvarname+$indexValue")
+                            in WordDatatypes -> {
+                                if(incr)
+                                    asmgen.out(" inc  $asmArrayvarname+$indexValue |  bne  + |  inc  $asmArrayvarname+$indexValue+1 |+")
+                                else
+                                    asmgen.out("""
+        lda  $asmArrayvarname+$indexValue
+        bne  +
+        dec  $asmArrayvarname+$indexValue+1
++       dec  $asmArrayvarname+$indexValue 
+""")
+                            }
+                            DataType.FLOAT -> {
+                                asmgen.out("  lda  #<$asmArrayvarname+$indexValue |  ldy  #>$asmArrayvarname+$indexValue")
+                                asmgen.out(if(incr) "  jsr  c64flt.inc_var_f" else "  jsr  c64flt.dec_var_f")
+                            }
+                            else -> throw AssemblyError("need numeric type")
+                        }
+                    }
+                    else -> {
+                        asmgen.loadScaledArrayIndexIntoRegister(targetArrayIdx, elementDt, CpuRegister.A)
+                        asmgen.out("  stx  P8ZP_SCRATCH_REG_X |  tax")
+                        when(elementDt) {
+                            in ByteDatatypes -> {
+                                asmgen.out(if(incr) "  inc  $asmArrayvarname,x" else "  dec  $asmArrayvarname,x")
+                            }
+                            in WordDatatypes -> {
+                                if(incr)
+                                    asmgen.out(" inc  $asmArrayvarname,x |  bne  + |  inc  $asmArrayvarname+1,x |+")
+                                else
+                                    asmgen.out("""
+        lda  $asmArrayvarname,x
+        bne  +
+        dec  $asmArrayvarname+1,x
++       dec  $asmArrayvarname 
+""")
+                            }
+                            DataType.FLOAT -> {
+                                asmgen.out("""
+                        ldy  #>$asmArrayvarname
+                        clc
+                        adc  #<$asmArrayvarname
+                        bcc  +
+                        iny
++                       jsr  c64flt.inc_var_f""")
+                            }
+                            else -> throw AssemblyError("weird array elt dt")
+                        }
+                        asmgen.out("  ldx  P8ZP_SCRATCH_REG_X")
+                    }
+                }
+            }
+            else -> throw AssemblyError("weird target type ${stmt.target}")
+        }
+    }
+}

compiler/src/prog8/compiler/target/c64/codegen/assignment/AsmAssignment.kt

@@ -0,0 +1,164 @@
+package prog8.compiler.target.c64.codegen.assignment
+
+import prog8.ast.Program
+import prog8.ast.base.*
+import prog8.ast.expressions.*
+import prog8.ast.statements.AssignTarget
+import prog8.ast.statements.Assignment
+import prog8.ast.statements.DirectMemoryWrite
+import prog8.compiler.AssemblyError
+import prog8.compiler.target.c64.codegen.AsmGen
+
+
+internal enum class TargetStorageKind {
+    VARIABLE,
+    ARRAY,
+    MEMORY,
+    REGISTER,
+    STACK
+}
+
+internal enum class SourceStorageKind {
+    LITERALNUMBER,
+    VARIABLE,
+    ARRAY,
+    MEMORY,
+    REGISTER,
+    STACK,              // value is already present on stack
+    EXPRESSION,         // expression in ast-form, still to be evaluated
+}
+
+internal class AsmAssignTarget(val kind: TargetStorageKind,
+                               program: Program,
+                               asmgen: AsmGen,
+                               val datatype: DataType,
+                               val variable: IdentifierReference? = null,
+                               val array: ArrayIndexedExpression? = null,
+                               val memory: DirectMemoryWrite? = null,
+                               val register: RegisterOrPair? = null,
+                               val origAstTarget: AssignTarget? = null
+                               )
+{
+    val constMemoryAddress by lazy { memory?.addressExpression?.constValue(program)?.number?.toInt() ?: 0}
+    val constArrayIndexValue by lazy { array?.arrayspec?.constIndex() }
+    val vardecl by lazy { variable?.targetVarDecl(program.namespace)!! }
+    val asmVarname by lazy {
+        if(variable!=null)
+            asmgen.asmVariableName(variable)
+        else
+            asmgen.asmVariableName(array!!.identifier)
+    }
+
+    lateinit var origAssign: AsmAssignment
+
+    init {
+        if(variable!=null && vardecl.type == VarDeclType.CONST)
+            throw AssemblyError("can't assign to a constant")
+        if(register!=null && datatype !in IntegerDatatypes)
+            throw AssemblyError("register must be integer type")
+    }
+
+    companion object {
+        fun fromAstAssignment(assign: Assignment, program: Program, asmgen: AsmGen): AsmAssignTarget = with(assign.target) {
+            val dt = inferType(program, assign).typeOrElse(DataType.STRUCT)
+            when {
+                identifier != null -> AsmAssignTarget(TargetStorageKind.VARIABLE, program, asmgen, dt, variable=identifier, origAstTarget =  this)
+                arrayindexed != null -> AsmAssignTarget(TargetStorageKind.ARRAY, program, asmgen, dt, array = arrayindexed, origAstTarget =  this)
+                memoryAddress != null -> AsmAssignTarget(TargetStorageKind.MEMORY, program, asmgen, dt, memory =  memoryAddress, origAstTarget =  this)
+                else -> throw AssemblyError("weird target")
+            }
+        }
+
+        fun fromRegisters(registers: RegisterOrPair, program: Program, asmgen: AsmGen): AsmAssignTarget =
+                when(registers) {
+                    RegisterOrPair.A,
+                    RegisterOrPair.X,
+                    RegisterOrPair.Y -> AsmAssignTarget(TargetStorageKind.REGISTER, program, asmgen, DataType.UBYTE, register = registers)
+                    RegisterOrPair.AX,
+                    RegisterOrPair.AY,
+                    RegisterOrPair.XY -> AsmAssignTarget(TargetStorageKind.REGISTER, program, asmgen, DataType.UWORD, register = registers)
+                }
+    }
+}
+
+internal class AsmAssignSource(val kind: SourceStorageKind,
+                               private val program: Program,
+                               val datatype: DataType,
+                               val variable: IdentifierReference? = null,
+                               val array: ArrayIndexedExpression? = null,
+                               val memory: DirectMemoryRead? = null,
+                               val register: CpuRegister? = null,
+                               val number: NumericLiteralValue? = null,
+                               val expression: Expression? = null
+)
+{
+    val constMemoryAddress by lazy { memory?.addressExpression?.constValue(program)?.number?.toInt() ?: 0}
+    val constArrayIndexValue by lazy { array?.arrayspec?.constIndex() }
+    val vardecl by lazy { variable?.targetVarDecl(program.namespace)!! }
+
+    companion object {
+        fun fromAstSource(value: Expression, program: Program): AsmAssignSource {
+            val cv = value.constValue(program)
+            if(cv!=null)
+                return AsmAssignSource(SourceStorageKind.LITERALNUMBER, program, cv.type, number = cv)
+
+            return when(value) {
+                is NumericLiteralValue -> AsmAssignSource(SourceStorageKind.LITERALNUMBER, program, value.type, number = cv)
+                is StringLiteralValue -> throw AssemblyError("string literal value should not occur anymore for asm generation")
+                is ArrayLiteralValue -> throw AssemblyError("array literal value should not occur anymore for asm generation")
+                is IdentifierReference -> {
+                    val dt = value.inferType(program).typeOrElse(DataType.STRUCT)
+                    AsmAssignSource(SourceStorageKind.VARIABLE, program, dt, variable = value)
+                }
+                is DirectMemoryRead -> {
+                    AsmAssignSource(SourceStorageKind.MEMORY, program, DataType.UBYTE, memory = value)
+                }
+                is ArrayIndexedExpression -> {
+                    val dt = value.inferType(program).typeOrElse(DataType.STRUCT)
+                    AsmAssignSource(SourceStorageKind.ARRAY, program, dt, array = value)
+                }
+                else -> {
+                    val dt = value.inferType(program).typeOrElse(DataType.STRUCT)
+                    AsmAssignSource(SourceStorageKind.EXPRESSION, program, dt, expression = value)
+                }
+            }
+        }
+    }
+
+    fun getAstValue(): Expression = when(kind) {
+        SourceStorageKind.LITERALNUMBER -> number!!
+        SourceStorageKind.VARIABLE -> variable!!
+        SourceStorageKind.ARRAY -> array!!
+        SourceStorageKind.MEMORY -> memory!!
+        SourceStorageKind.EXPRESSION -> expression!!
+        SourceStorageKind.REGISTER -> throw AssemblyError("cannot get a register source as Ast node")
+        SourceStorageKind.STACK -> throw AssemblyError("cannot get a stack source as Ast node")
+    }
+
+    fun withAdjustedDt(newType: DataType) =
+            AsmAssignSource(kind, program, newType, variable, array, memory, register, number, expression)
+
+    fun adjustDataTypeToTarget(target: AsmAssignTarget): AsmAssignSource {
+        // allow some signed/unsigned relaxations
+        if(target.datatype!=datatype) {
+            if(target.datatype in ByteDatatypes && datatype in ByteDatatypes) {
+                return withAdjustedDt(target.datatype)
+            } else if(target.datatype in WordDatatypes && datatype in WordDatatypes) {
+                return withAdjustedDt(target.datatype)
+            }
+        }
+        return this
+    }
+
+}
+
+
+internal class AsmAssignment(val source: AsmAssignSource,
+                             val target: AsmAssignTarget,
+                             val isAugmentable: Boolean,
+                             val position: Position) {
+
+    init {
+        require(source.datatype==target.datatype) {"source and target datatype must be identical"}
+    }
+}

compiler/src/prog8/compiler/target/c64/codegen/assignment/AssignmentAsmGen.kt

@@ -0,0 +1,955 @@
+package prog8.compiler.target.c64.codegen.assignment
+
+import prog8.ast.Program
+import prog8.ast.base.*
+import prog8.ast.expressions.*
+import prog8.ast.statements.*
+import prog8.compiler.AssemblyError
+import prog8.compiler.target.c64.codegen.AsmGen
+import prog8.compiler.toHex
+
+
+internal class AssignmentAsmGen(private val program: Program, private val asmgen: AsmGen) {
+
+    private val augmentableAsmGen = AugmentableAssignmentAsmGen(program, this, asmgen)
+
+    fun translate(assignment: Assignment) {
+        val target = AsmAssignTarget.fromAstAssignment(assignment, program, asmgen)
+        val source = AsmAssignSource.fromAstSource(assignment.value, program).adjustDataTypeToTarget(target)
+
+        val assign = AsmAssignment(source, target, assignment.isAugmentable, assignment.position)
+        target.origAssign = assign
+
+        if(assign.isAugmentable)
+            augmentableAsmGen.translate(assign)
+        else
+            translateNormalAssignment(assign)
+    }
+
+    fun translateNormalAssignment(assign: AsmAssignment) {
+        when(assign.source.kind) {
+            SourceStorageKind.LITERALNUMBER -> {
+                // simple case: assign a constant number
+                val num = assign.source.number!!.number
+                when (assign.source.datatype) {
+                    DataType.UBYTE, DataType.BYTE -> assignConstantByte(assign.target, num.toShort())
+                    DataType.UWORD, DataType.WORD -> assignConstantWord(assign.target, num.toInt())
+                    DataType.FLOAT -> assignConstantFloat(assign.target, num.toDouble())
+                    else -> throw AssemblyError("weird numval type")
+                }
+            }
+            SourceStorageKind.VARIABLE -> {
+                // simple case: assign from another variable
+                val variable = assign.source.variable!!
+                when (assign.source.datatype) {
+                    DataType.UBYTE, DataType.BYTE -> assignVariableByte(assign.target, variable)
+                    DataType.UWORD, DataType.WORD -> assignVariableWord(assign.target, variable)
+                    DataType.FLOAT -> assignVariableFloat(assign.target, variable)
+                    in PassByReferenceDatatypes -> assignAddressOf(assign.target, variable)
+                    else -> throw AssemblyError("unsupported assignment target type ${assign.target.datatype}")
+                }
+            }
+            SourceStorageKind.ARRAY -> {
+                val value = assign.source.array!!
+                val elementDt = assign.source.datatype
+                val index = value.arrayspec.index
+                val arrayVarName = asmgen.asmVariableName(value.identifier)
+                if (index is NumericLiteralValue) {
+                    // constant array index value
+                    val indexValue = index.number.toInt() * elementDt.memorySize()
+                    when (elementDt) {
+                        in ByteDatatypes ->
+                            asmgen.out("  lda  $arrayVarName+$indexValue |  sta  P8ESTACK_LO,x |  dex")
+                        in WordDatatypes ->
+                            asmgen.out("  lda  $arrayVarName+$indexValue |  sta  P8ESTACK_LO,x |  lda  $arrayVarName+$indexValue+1 |  sta  P8ESTACK_HI,x | dex")
+                        DataType.FLOAT ->
+                            asmgen.out("  lda  #<$arrayVarName+$indexValue |  ldy  #>$arrayVarName+$indexValue |  jsr  c64flt.push_float")
+                        else ->
+                            throw AssemblyError("weird array type")
+                    }
+                } else {
+                    when (elementDt) {
+                        in ByteDatatypes -> {
+                            asmgen.loadScaledArrayIndexIntoRegister(value, elementDt, CpuRegister.Y)
+                            asmgen.out("  lda  $arrayVarName,y |  sta  P8ESTACK_LO,x |  dex")
+                        }
+                        in WordDatatypes  -> {
+                            asmgen.loadScaledArrayIndexIntoRegister(value, elementDt, CpuRegister.Y)
+                            asmgen.out("  lda  $arrayVarName,y |  sta  P8ESTACK_LO,x |  lda  $arrayVarName+1,y |  sta  P8ESTACK_HI,x |  dex")
+                        }
+                        DataType.FLOAT -> {
+                            asmgen.loadScaledArrayIndexIntoRegister(value, elementDt, CpuRegister.A)
+                            asmgen.out("""
+                                ldy  #>$arrayVarName
+                                clc
+                                adc  #<$arrayVarName
+                                bcc  +
+                                iny
++                               jsr  c64flt.push_float""")
+                        }
+                        else ->
+                            throw AssemblyError("weird array elt type")
+                    }
+                }
+                assignStackValue(assign.target)
+            }
+            SourceStorageKind.MEMORY -> {
+                val value = assign.source.memory!!
+                when (value.addressExpression) {
+                    is NumericLiteralValue -> {
+                        val address = (value.addressExpression as NumericLiteralValue).number.toInt()
+                        assignMemoryByte(assign.target, address, null)
+                    }
+                    is IdentifierReference -> {
+                        assignMemoryByte(assign.target, null, value.addressExpression as IdentifierReference)
+                    }
+                    else -> {
+                        asmgen.translateExpression(value.addressExpression)
+                        asmgen.out("  jsr  prog8_lib.read_byte_from_address_on_stack |  inx")
+                        assignRegisterByte(assign.target, CpuRegister.A)
+                    }
+                }
+            }
+            SourceStorageKind.EXPRESSION -> {
+                val value = assign.source.expression!!
+                when(value) {
+                    is AddressOf -> assignAddressOf(assign.target, value.identifier)
+                    is NumericLiteralValue -> throw AssemblyError("source kind should have been literalnumber")
+                    is IdentifierReference -> throw AssemblyError("source kind should have been variable")
+                    is ArrayIndexedExpression -> throw AssemblyError("source kind should have been array")
+                    is DirectMemoryRead -> throw AssemblyError("source kind should have been memory")
+//                    is TypecastExpression -> {
+//                        if(assign.target.kind == TargetStorageKind.STACK) {
+//                            asmgen.translateExpression(value)
+//                            assignStackValue(assign.target)
+//                        } else {
+//                            println("!!!!TYPECAST to ${assign.target.kind} $value")
+//                            // TODO maybe we can do the typecast on the target directly instead of on the stack?
+//                            asmgen.translateExpression(value)
+//                            assignStackValue(assign.target)
+//                        }
+//                    }
+//                    is FunctionCall -> {
+//                        if (assign.target.kind == TargetStorageKind.STACK) {
+//                            asmgen.translateExpression(value)
+//                            assignStackValue(assign.target)
+//                        } else {
+//                            val functionName = value.target.nameInSource.last()
+//                            val builtinFunc = BuiltinFunctions[functionName]
+//                            if (builtinFunc != null) {
+//                                println("!!!!BUILTIN-FUNCCALL target=${assign.target.kind} $value") // TODO optimize certain functions?
+//                            }
+//                            asmgen.translateExpression(value)
+//                            assignStackValue(assign.target)
+//                        }
+//                    }
+                    else -> {
+                        // everything else just evaluate via the stack.
+                        asmgen.translateExpression(value)
+                        assignStackValue(assign.target)
+                    }
+                }
+            }
+            SourceStorageKind.REGISTER -> {
+                assignRegisterByte(assign.target, assign.source.register!!)
+            }
+            SourceStorageKind.STACK -> {
+                assignStackValue(assign.target)
+            }
+        }
+    }
+
+    private fun assignStackValue(target: AsmAssignTarget) {
+        when(target.kind) {
+            TargetStorageKind.VARIABLE -> {
+                when (target.datatype) {
+                    DataType.UBYTE, DataType.BYTE -> {
+                        asmgen.out(" inx | lda  P8ESTACK_LO,x  | sta  ${target.asmVarname}")
+                    }
+                    DataType.UWORD, DataType.WORD -> {
+                        asmgen.out("""
+                            inx
+                            lda  P8ESTACK_LO,x
+                            sta  ${target.asmVarname}
+                            lda  P8ESTACK_HI,x
+                            sta  ${target.asmVarname}+1
+                        """)
+                    }
+                    DataType.FLOAT -> {
+                        asmgen.out("""
+                            lda  #<${target.asmVarname}
+                            ldy  #>${target.asmVarname}
+                            jsr  c64flt.pop_float
+                        """)
+                    }
+                    else -> throw AssemblyError("weird target variable type ${target.datatype}")
+                }
+            }
+            TargetStorageKind.MEMORY -> {
+                asmgen.out("  inx")
+                storeByteViaRegisterAInMemoryAddress("P8ESTACK_LO,x", target.memory!!)
+            }
+            TargetStorageKind.ARRAY -> {
+                val index = target.array!!.arrayspec.index
+                when {
+                    target.constArrayIndexValue!=null -> {
+                        val scaledIdx = target.constArrayIndexValue!! * target.datatype.memorySize()
+                        when(target.datatype) {
+                            in ByteDatatypes -> {
+                                asmgen.out(" inx | lda  P8ESTACK_LO,x  | sta  ${target.asmVarname}+$scaledIdx")
+                            }
+                            in WordDatatypes -> {
+                                asmgen.out("""
+                                    inx
+                                    lda  P8ESTACK_LO,x
+                                    sta  ${target.asmVarname}+$scaledIdx
+                                    lda  P8ESTACK_HI,x
+                                    sta  ${target.asmVarname}+$scaledIdx+1
+                                """)
+                            }
+                            DataType.FLOAT -> {
+                                asmgen.out("""
+                                    lda  #<${target.asmVarname}+$scaledIdx
+                                    ldy  #>${target.asmVarname}+$scaledIdx
+                                    jsr  c64flt.pop_float
+                                """)
+                            }
+                            else -> throw AssemblyError("weird target variable type ${target.datatype}")
+                        }
+                    }
+                    index is IdentifierReference -> {
+                        when(target.datatype) {
+                            DataType.UBYTE, DataType.BYTE -> {
+                                asmgen.loadScaledArrayIndexIntoRegister(target.array, target.datatype, CpuRegister.Y)
+                                asmgen.out(" inx |  lda  P8ESTACK_LO,x |  sta  ${target.asmVarname},y")
+                            }
+                            DataType.UWORD, DataType.WORD -> {
+                                asmgen.loadScaledArrayIndexIntoRegister(target.array, target.datatype, CpuRegister.Y)
+                                asmgen.out("""
+                                    inx
+                                    lda  P8ESTACK_LO,x
+                                    sta  ${target.asmVarname},y
+                                    lda  P8ESTACK_HI,x
+                                    sta  ${target.asmVarname}+1,y
+                                """)
+                            }
+                            DataType.FLOAT -> {
+                                asmgen.loadScaledArrayIndexIntoRegister(target.array, target.datatype, CpuRegister.A)
+                                asmgen.out("""
+                                    ldy  #>${target.asmVarname}
+                                    clc
+                                    adc  #<${target.asmVarname}
+                                    bcc  +
+                                    iny
++                                   jsr  c64flt.pop_float""")
+                            }
+                            else -> throw AssemblyError("weird dt")
+                        }
+                    }
+                    else -> {
+                        asmgen.translateExpression(index)
+                        asmgen.out("  inx |  lda  P8ESTACK_LO,x")
+                        popAndWriteArrayvalueWithUnscaledIndexA(target.datatype, target.asmVarname)
+                    }
+                }
+            }
+            TargetStorageKind.REGISTER -> {
+                when (target.datatype) {
+                    DataType.UBYTE, DataType.BYTE -> {
+                        when(target.register!!) {
+                            RegisterOrPair.A -> asmgen.out(" inx |  lda  P8ESTACK_LO,x")
+                            RegisterOrPair.X -> throw AssemblyError("can't use X here")
+                            RegisterOrPair.Y -> asmgen.out(" inx |  ldy  P8ESTACK_LO,x")
+                            else -> throw AssemblyError("can't assign byte to register pair word")
+                        }
+                    }
+                    DataType.UWORD, DataType.WORD, in PassByReferenceDatatypes -> {
+                        when(target.register!!) {
+                            RegisterOrPair.AX -> throw AssemblyError("can't use X here")
+                            RegisterOrPair.AY-> asmgen.out(" inx |  lda  P8ESTACK_LO,x |  ldy  P8ESTACK_HI,x")
+                            RegisterOrPair.XY-> throw AssemblyError("can't use X here")
+                            else -> throw AssemblyError("can't assign word to single byte register")
+                        }
+                    }
+                    else -> throw AssemblyError("weird dt")
+                }
+            }
+            TargetStorageKind.STACK -> {}
+        }
+    }
+
+    private fun assignAddressOf(target: AsmAssignTarget, name: IdentifierReference) {
+        val struct = name.memberOfStruct(program.namespace)
+        val sourceName = if (struct != null) {
+            // take the address of the first struct member instead
+            val decl = name.targetVarDecl(program.namespace)!!
+            val firstStructMember = struct.nameOfFirstMember()
+            // find the flattened var that belongs to this first struct member
+            val firstVarName = listOf(decl.name, firstStructMember)
+            val firstVar = name.definingScope().lookup(firstVarName, name) as VarDecl
+            firstVar.name
+        } else {
+            asmgen.fixNameSymbols(name.nameInSource.joinToString("."))
+        }
+
+        when(target.kind) {
+            TargetStorageKind.VARIABLE -> {
+                asmgen.out("""
+                        lda  #<$sourceName
+                        ldy  #>$sourceName
+                        sta  ${target.asmVarname}
+                        sty  ${target.asmVarname}+1
+                    """)
+            }
+            TargetStorageKind.MEMORY -> {
+                throw AssemblyError("no asm gen for assign address $sourceName to memory word $target")
+            }
+            TargetStorageKind.ARRAY -> {
+                throw AssemblyError("no asm gen for assign address $sourceName to array ${target.asmVarname}")
+            }
+            TargetStorageKind.REGISTER -> {
+                when(target.register!!) {
+                    RegisterOrPair.AX -> asmgen.out("  lda  #<$sourceName |  ldx  #>$sourceName")
+                    RegisterOrPair.AY -> asmgen.out("  lda  #<$sourceName |  ldy  #>$sourceName")
+                    RegisterOrPair.XY -> asmgen.out("  ldx  #<$sourceName |  ldy  #>$sourceName")
+                    else -> throw AssemblyError("can't load address in a single 8-bit register")
+                }
+            }
+            TargetStorageKind.STACK -> {
+                val srcname = asmgen.asmVariableName(name)
+                asmgen.out("""
+                    lda  #<$srcname
+                    sta  P8ESTACK_LO,x
+                    lda  #>$srcname
+                    sta  P8ESTACK_HI,x
+                    dex""")
+            }
+        }
+    }
+
+    private fun assignVariableWord(target: AsmAssignTarget, variable: IdentifierReference) {
+        val sourceName = asmgen.asmVariableName(variable)
+        when(target.kind) {
+            TargetStorageKind.VARIABLE -> {
+                asmgen.out("""
+                    lda  $sourceName
+                    ldy  $sourceName+1
+                    sta  ${target.asmVarname}
+                    sty  ${target.asmVarname}+1
+                """)
+            }
+            TargetStorageKind.MEMORY -> {
+                throw AssemblyError("no asm gen for assign wordvar $sourceName to memory ${target.memory}")
+            }
+            TargetStorageKind.ARRAY -> {
+                val index = target.array!!.arrayspec.index
+                when {
+                    target.constArrayIndexValue!=null -> {
+                        val scaledIdx = target.constArrayIndexValue!! * target.datatype.memorySize()
+                        when(target.datatype) {
+                            in ByteDatatypes -> {
+                                asmgen.out(" lda  $sourceName  | sta  ${target.asmVarname}+$scaledIdx")
+                            }
+                            in WordDatatypes -> {
+                                asmgen.out("""
+                                    lda  $sourceName
+                                    sta  ${target.asmVarname}+$scaledIdx
+                                    lda  $sourceName+1
+                                    sta  ${target.asmVarname}+$scaledIdx+1
+                                """)
+                            }
+                            DataType.FLOAT -> {
+                                asmgen.out("""
+                                    lda  #<$sourceName
+                                    ldy  #>$sourceName
+                                    sta  P8ZP_SCRATCH_W1
+                                    sty  P8ZP_SCRATCH_W1+1
+                                    lda  #<${target.asmVarname}+$scaledIdx
+                                    ldy  #>${target.asmVarname}+$scaledIdx
+                                    jsr  c64flt.copy_float
+                                """)
+                            }
+                            else -> throw AssemblyError("weird target variable type ${target.datatype}")
+                        }
+                    }
+                    index is IdentifierReference -> {
+                        when(target.datatype) {
+                            DataType.UBYTE, DataType.BYTE -> {
+                                asmgen.loadScaledArrayIndexIntoRegister(target.array, target.datatype, CpuRegister.Y)
+                                asmgen.out(" lda  $sourceName |  sta  ${target.asmVarname},y")
+                            }
+                            DataType.UWORD, DataType.WORD -> {
+                                asmgen.loadScaledArrayIndexIntoRegister(target.array, target.datatype, CpuRegister.Y)
+                                asmgen.out("""
+                                    lda  $sourceName
+                                    sta  ${target.asmVarname},y
+                                    lda  $sourceName+1
+                                    sta  ${target.asmVarname}+1,y
+                                """)
+                            }
+                            DataType.FLOAT -> {
+                                asmgen.loadScaledArrayIndexIntoRegister(target.array, target.datatype, CpuRegister.A)
+                                asmgen.out("""
+                                    ldy  #<$sourceName
+                                    sty  P8ZP_SCRATCH_W1
+                                    ldy  #>$sourceName
+                                    sty  P8ZP_SCRATCH_W1+1
+                                    ldy  #>${target.asmVarname}
+                                    clc
+                                    adc  #<${target.asmVarname}
+                                    bcc  +
+                                    iny
++                                   jsr  c64flt.copy_float""")
+                            }
+                            else -> throw AssemblyError("weird dt")
+                        }
+                    }
+                    else -> {
+                        asmgen.out("  lda  $sourceName |  sta  P8ESTACK_LO,x |  lda  $sourceName+1 |  sta  P8ESTACK_HI,x |  dex")
+                        asmgen.translateExpression(index)
+                        asmgen.out("  inx |  lda  P8ESTACK_LO,x")
+                        popAndWriteArrayvalueWithUnscaledIndexA(target.datatype, target.asmVarname)
+                    }
+                }
+            }
+            TargetStorageKind.REGISTER -> {
+                when(target.register!!) {
+                    RegisterOrPair.AX -> asmgen.out("  lda  $sourceName |  ldx  $sourceName+1")
+                    RegisterOrPair.AY -> asmgen.out("  lda  $sourceName |  ldy  $sourceName+1")
+                    RegisterOrPair.XY -> asmgen.out("  ldx  $sourceName |  ldy  $sourceName+1")
+                    else -> throw AssemblyError("can't load word in a single 8-bit register")
+                }
+            }
+            TargetStorageKind.STACK -> {
+                asmgen.out("""
+                    lda  #$sourceName
+                    sta  P8ESTACK_LO,x
+                    lda  #$sourceName+1
+                    sta  P8ESTACK_HI,x
+                    dex""")
+            }
+        }
+    }
+
+    private fun assignVariableFloat(target: AsmAssignTarget, variable: IdentifierReference) {
+        val sourceName = asmgen.asmVariableName(variable)
+        when(target.kind) {
+            TargetStorageKind.VARIABLE -> {
+                asmgen.out("""
+                    lda  $sourceName
+                    sta  ${target.asmVarname}
+                    lda  $sourceName+1
+                    sta  ${target.asmVarname}+1
+                    lda  $sourceName+2
+                    sta  ${target.asmVarname}+2
+                    lda  $sourceName+3
+                    sta  ${target.asmVarname}+3
+                    lda  $sourceName+4
+                    sta  ${target.asmVarname}+4
+                """)
+            }
+            TargetStorageKind.ARRAY -> {
+                // TODO optimize this, but the situation doesn't occur very often
+//                if(target.constArrayIndexValue!=null) {
+//                    TODO("const index ${target.constArrayIndexValue}")
+//                } else if(target.array!!.arrayspec.index is IdentifierReference) {
+//                    TODO("array[var] ${target.constArrayIndexValue}")
+//                }
+                val index = target.array!!.arrayspec.index
+                asmgen.out("  lda  #<$sourceName |  ldy  #>$sourceName |  jsr  c64flt.push_float")
+                asmgen.translateExpression(index)
+                asmgen.out("  lda  #<${target.asmVarname} |  ldy  #>${target.asmVarname} |  jsr  c64flt.pop_float_to_indexed_var")
+            }
+            TargetStorageKind.MEMORY -> throw AssemblyError("can't assign float to mem byte")
+            TargetStorageKind.REGISTER -> throw AssemblyError("can't assign float to register")
+            TargetStorageKind.STACK -> asmgen.out("  lda  #<$sourceName |  ldy  #>$sourceName |  jsr  c64flt.push_float")
+        }
+    }
+
+    private fun assignVariableByte(target: AsmAssignTarget, variable: IdentifierReference) {
+        val sourceName = asmgen.asmVariableName(variable)
+        when(target.kind) {
+            TargetStorageKind.VARIABLE -> {
+                asmgen.out("""
+                    lda  $sourceName
+                    sta  ${target.asmVarname}
+                    """)
+            }
+            TargetStorageKind.MEMORY -> {
+                storeByteViaRegisterAInMemoryAddress(sourceName, target.memory!!)
+            }
+            TargetStorageKind.ARRAY -> {
+                val index = target.array!!.arrayspec.index
+                when {
+                    target.constArrayIndexValue!=null -> {
+                        val scaledIdx = target.constArrayIndexValue!! * target.datatype.memorySize()
+                        asmgen.out(" lda  $sourceName  | sta  ${target.asmVarname}+$scaledIdx")
+                    }
+                    index is IdentifierReference -> {
+                        asmgen.loadScaledArrayIndexIntoRegister(target.array, target.datatype, CpuRegister.Y)
+                        asmgen.out(" lda  $sourceName |  sta  ${target.asmVarname},y")
+                    }
+                    else -> {
+                        asmgen.out("  lda  $sourceName |  sta  P8ESTACK_LO,x |  dex")
+                        asmgen.translateExpression(index)
+                        asmgen.out("  inx |  lda  P8ESTACK_LO,x")
+                        popAndWriteArrayvalueWithUnscaledIndexA(target.datatype, target.asmVarname)
+                    }
+                }
+            }
+            TargetStorageKind.REGISTER -> {
+                when(target.register!!) {
+                    RegisterOrPair.A -> asmgen.out("  lda  $sourceName")
+                    RegisterOrPair.X -> asmgen.out("  ldx  $sourceName")
+                    RegisterOrPair.Y -> asmgen.out("  ldy  $sourceName")
+                    RegisterOrPair.AX -> asmgen.out("  lda  $sourceName |  ldx  #0")
+                    RegisterOrPair.AY -> asmgen.out("  lda  $sourceName |  ldy  #0")
+                    RegisterOrPair.XY -> asmgen.out("  ldx  $sourceName |  ldy  #0")
+                }
+            }
+            TargetStorageKind.STACK -> {
+                asmgen.out("""
+                    lda  #$sourceName
+                    sta  P8ESTACK_LO,x
+                    dex""")
+            }
+        }
+    }
+
+    private fun assignRegisterByte(target: AsmAssignTarget, register: CpuRegister) {
+        require(target.datatype in ByteDatatypes)
+        when(target.kind) {
+            TargetStorageKind.VARIABLE -> {
+                asmgen.out("  st${register.name.toLowerCase()}  ${target.asmVarname}")
+            }
+            TargetStorageKind.MEMORY -> {
+                storeRegisterInMemoryAddress(register, target.memory!!)
+            }
+            TargetStorageKind.ARRAY -> {
+                val index = target.array!!.arrayspec.index
+                when (index) {
+                    is NumericLiteralValue -> {
+                        val memindex = index.number.toInt()
+                        when (register) {
+                            CpuRegister.A -> asmgen.out("  sta  ${target.asmVarname}+$memindex")
+                            CpuRegister.X -> asmgen.out("  stx  ${target.asmVarname}+$memindex")
+                            CpuRegister.Y -> asmgen.out("  sty  ${target.asmVarname}+$memindex")
+                        }
+                    }
+                    is IdentifierReference -> {
+                        when (register) {
+                            CpuRegister.A -> {}
+                            CpuRegister.X -> asmgen.out(" txa")
+                            CpuRegister.Y -> asmgen.out(" tya")
+                        }
+                        asmgen.out(" ldy  ${asmgen.asmVariableName(index)} |  sta  ${target.asmVarname},y")
+                    }
+                    else -> {
+                        asmgen.saveRegister(register)
+                        asmgen.translateExpression(index)
+                        asmgen.restoreRegister(register)
+                        when (register) {
+                            CpuRegister.A -> asmgen.out("  sta  P8ZP_SCRATCH_B1")
+                            CpuRegister.X -> asmgen.out("  stx  P8ZP_SCRATCH_B1")
+                            CpuRegister.Y -> asmgen.out("  sty  P8ZP_SCRATCH_B1")
+                        }
+                        asmgen.out("""
+                            inx
+                            lda  P8ESTACK_LO,x
+                            tay
+                            lda  P8ZP_SCRATCH_B1
+                            sta  ${target.asmVarname},y  
+                        """)
+                    }
+                }
+            }
+            TargetStorageKind.REGISTER -> {
+                when(register) {
+                    CpuRegister.A -> when(target.register!!) {
+                        RegisterOrPair.A -> {}
+                        RegisterOrPair.X -> { asmgen.out("  tax") }
+                        RegisterOrPair.Y -> { asmgen.out("  tay") }
+                        else -> throw AssemblyError("attempt to assign byte to register pair word")
+                    }
+                    CpuRegister.X -> when(target.register!!) {
+                        RegisterOrPair.A -> { asmgen.out("  txa") }
+                        RegisterOrPair.X -> {  }
+                        RegisterOrPair.Y -> { asmgen.out("  txy") }
+                        else -> throw AssemblyError("attempt to assign byte to register pair word")
+                    }
+                    CpuRegister.Y -> when(target.register!!) {
+                        RegisterOrPair.A -> { asmgen.out("  tya") }
+                        RegisterOrPair.X -> { asmgen.out("  tyx") }
+                        RegisterOrPair.Y -> { }
+                        else -> throw AssemblyError("attempt to assign byte to register pair word")
+                    }
+                }
+            }
+            TargetStorageKind.STACK -> {
+                when(register) {
+                    CpuRegister.A -> asmgen.out(" sta  P8ESTACK_LO,x |  dex")
+                    CpuRegister.X -> throw AssemblyError("can't use X here")
+                    CpuRegister.Y -> asmgen.out(" tya |  sta  P8ESTACK_LO,x |  dex")
+                }
+            }
+        }
+    }
+
+    private fun assignConstantWord(target: AsmAssignTarget, word: Int) {
+        when(target.kind) {
+            TargetStorageKind.VARIABLE -> {
+                if (word ushr 8 == word and 255) {
+                    // lsb=msb
+                    asmgen.out("""
+                    lda  #${(word and 255).toHex()}
+                    sta  ${target.asmVarname}
+                    sta  ${target.asmVarname}+1
+                """)
+                } else {
+                    asmgen.out("""
+                    lda  #<${word.toHex()}
+                    ldy  #>${word.toHex()}
+                    sta  ${target.asmVarname}
+                    sty  ${target.asmVarname}+1
+                """)
+                }
+            }
+            TargetStorageKind.MEMORY -> {
+                throw AssemblyError("no asm gen for assign word $word to memory ${target.memory}")
+            }
+            TargetStorageKind.ARRAY -> {
+                // TODO optimize this, but the situation doesn't occur very often
+//                if(target.constArrayIndexValue!=null) {
+//                    TODO("const index ${target.constArrayIndexValue}")
+//                } else if(target.array!!.arrayspec.index is IdentifierReference) {
+//                    TODO("array[var] ${target.constArrayIndexValue}")
+//                }
+                val index = target.array!!.arrayspec.index
+                asmgen.translateExpression(index)
+                asmgen.out("""
+                    inx
+                    lda  P8ESTACK_LO,x
+                    asl  a
+                    tay
+                    lda  #<${word.toHex()}
+                    sta  ${target.asmVarname},y
+                    lda  #>${word.toHex()}
+                    sta  ${target.asmVarname}+1,y
+                """)
+            }
+            TargetStorageKind.REGISTER -> {
+                when(target.register!!) {
+                    RegisterOrPair.AX -> asmgen.out("  lda  #<${word.toHex()} |  ldx  #>${word.toHex()}")
+                    RegisterOrPair.AY -> asmgen.out("  lda  #<${word.toHex()} |  ldy  #>${word.toHex()}")
+                    RegisterOrPair.XY -> asmgen.out("  ldx  #<${word.toHex()} |  ldy  #>${word.toHex()}")
+                    else -> throw AssemblyError("can't assign word to single byte register")
+                }
+            }
+            TargetStorageKind.STACK -> {
+                asmgen.out("""
+                    lda  #<${word.toHex()}
+                    sta  P8ESTACK_LO,x
+                    lda  #>${word.toHex()}
+                    sta  P8ESTACK_HI,x
+                    dex""")
+            }
+        }
+    }
+
+    private fun assignConstantByte(target: AsmAssignTarget, byte: Short) {
+        when(target.kind) {
+            TargetStorageKind.VARIABLE -> {
+                asmgen.out("  lda  #${byte.toHex()} |  sta  ${target.asmVarname} ")
+            }
+            TargetStorageKind.MEMORY -> {
+                storeByteViaRegisterAInMemoryAddress("#${byte.toHex()}", target.memory!!)
+            }
+            TargetStorageKind.ARRAY -> {
+                val index = target.array!!.arrayspec.index
+                when {
+                    target.constArrayIndexValue!=null -> {
+                        val indexValue = target.constArrayIndexValue!!
+                        asmgen.out("  lda  #${byte.toHex()} |  sta  ${target.asmVarname}+$indexValue")
+                    }
+                    index is IdentifierReference -> {
+                        asmgen.loadScaledArrayIndexIntoRegister(target.array, DataType.UBYTE, CpuRegister.Y)
+                        asmgen.out("  lda  #<${byte.toHex()} |  sta  ${target.asmVarname},y")
+                    }
+                    else -> {
+                        asmgen.translateExpression(index)
+                        asmgen.out("""
+                            inx
+                            ldy  P8ESTACK_LO,x
+                            lda  #${byte.toHex()}
+                            sta  ${target.asmVarname},y
+                        """)
+                    }
+                }
+            }
+            TargetStorageKind.REGISTER -> when(target.register!!) {
+                RegisterOrPair.A -> asmgen.out("  lda  #${byte.toHex()}")
+                RegisterOrPair.X -> asmgen.out("  ldx  #${byte.toHex()}")
+                RegisterOrPair.Y -> asmgen.out("  ldy  #${byte.toHex()}")
+                else -> throw AssemblyError("can't assign byte to word register apir")
+            }
+            TargetStorageKind.STACK -> {
+                asmgen.out("""
+                    lda  #${byte.toHex()}
+                    sta  P8ESTACK_LO,x
+                    dex""")
+            }
+        }
+    }
+
+    private fun assignConstantFloat(target: AsmAssignTarget, float: Double) {
+        if (float == 0.0) {
+            // optimized case for float zero
+            when(target.kind) {
+                TargetStorageKind.VARIABLE -> {
+                    asmgen.out("""
+                            lda  #0
+                            sta  ${target.asmVarname}
+                            sta  ${target.asmVarname}+1
+                            sta  ${target.asmVarname}+2
+                            sta  ${target.asmVarname}+3
+                            sta  ${target.asmVarname}+4
+                        """)
+                }
+                TargetStorageKind.ARRAY -> {
+                    // TODO optimize this, but the situation doesn't occur very often
+//                    if(target.constArrayIndexValue!=null) {
+//                        TODO("const index ${target.constArrayIndexValue}")
+//                    } else if(target.array!!.arrayspec.index is IdentifierReference) {
+//                        TODO("array[var] ${target.constArrayIndexValue}")
+//                    }
+                    val index = target.array!!.arrayspec.index
+                    if (index is NumericLiteralValue) {
+                        val indexValue = index.number.toInt() * DataType.FLOAT.memorySize()
+                        asmgen.out("""
+                            lda  #0
+                            sta  ${target.asmVarname}+$indexValue
+                            sta  ${target.asmVarname}+$indexValue+1
+                            sta  ${target.asmVarname}+$indexValue+2
+                            sta  ${target.asmVarname}+$indexValue+3
+                            sta  ${target.asmVarname}+$indexValue+4
+                        """)
+                    } else {
+                        asmgen.translateExpression(index)
+                        asmgen.out("""
+                            lda  #<${target.asmVarname}
+                            sta  P8ZP_SCRATCH_W1
+                            lda  #>${target.asmVarname}
+                            sta  P8ZP_SCRATCH_W1+1
+                            jsr  c64flt.set_0_array_float
+                        """)
+                    }
+                }
+                TargetStorageKind.MEMORY -> throw AssemblyError("can't assign float to memory byte")
+                TargetStorageKind.REGISTER -> throw AssemblyError("can't assign float to register")
+                TargetStorageKind.STACK -> {
+                    val floatConst = asmgen.getFloatAsmConst(float)
+                    asmgen.out(" lda  #<$floatConst |  ldy  #>$floatConst |  jsr  c64flt.push_float")
+                }
+            }
+        } else {
+            // non-zero value
+            val constFloat = asmgen.getFloatAsmConst(float)
+            when(target.kind) {
+                TargetStorageKind.VARIABLE -> {
+                    asmgen.out("""
+                            lda  $constFloat
+                            sta  ${target.asmVarname}
+                            lda  $constFloat+1
+                            sta  ${target.asmVarname}+1
+                            lda  $constFloat+2
+                            sta  ${target.asmVarname}+2
+                            lda  $constFloat+3
+                            sta  ${target.asmVarname}+3
+                            lda  $constFloat+4
+                            sta  ${target.asmVarname}+4
+                        """)
+                }
+                TargetStorageKind.ARRAY -> {
+                    // TODO optimize this, but the situation doesn't occur very often
+//                    if(target.constArrayIndexValue!=null) {
+//                        TODO("const index ${target.constArrayIndexValue}")
+//                    } else if(target.array!!.arrayspec.index is IdentifierReference) {
+//                        TODO("array[var] ${target.constArrayIndexValue}")
+//                    }
+                    val index = target.array!!.arrayspec.index
+                    val arrayVarName = target.asmVarname
+                    if (index is NumericLiteralValue) {
+                        val indexValue = index.number.toInt() * DataType.FLOAT.memorySize()
+                        asmgen.out("""
+                            lda  $constFloat
+                            sta  $arrayVarName+$indexValue
+                            lda  $constFloat+1
+                            sta  $arrayVarName+$indexValue+1
+                            lda  $constFloat+2
+                            sta  $arrayVarName+$indexValue+2
+                            lda  $constFloat+3
+                            sta  $arrayVarName+$indexValue+3
+                            lda  $constFloat+4
+                            sta  $arrayVarName+$indexValue+4
+                        """)
+                    } else {
+                        asmgen.translateExpression(index)
+                        asmgen.out("""
+                            lda  #<${constFloat}
+                            sta  P8ZP_SCRATCH_W1
+                            lda  #>${constFloat}
+                            sta  P8ZP_SCRATCH_W1+1
+                            lda  #<${arrayVarName}
+                            sta  P8ZP_SCRATCH_W2
+                            lda  #>${arrayVarName}
+                            sta  P8ZP_SCRATCH_W2+1
+                            jsr  c64flt.set_array_float
+                        """)
+                    }
+                }
+                TargetStorageKind.MEMORY -> throw AssemblyError("can't assign float to memory byte")
+                TargetStorageKind.REGISTER -> throw AssemblyError("can't assign float to register")
+                TargetStorageKind.STACK -> {
+                    val floatConst = asmgen.getFloatAsmConst(float)
+                    asmgen.out(" lda  #<$floatConst |  ldy  #>$floatConst |  jsr  c64flt.push_float")
+                }
+            }
+        }
+    }
+
+    private fun assignMemoryByte(target: AsmAssignTarget, address: Int?, identifier: IdentifierReference?) {
+        if (address != null) {
+            when(target.kind) {
+                TargetStorageKind.VARIABLE -> {
+                    asmgen.out("""
+                        lda  ${address.toHex()}
+                        sta  ${target.asmVarname}
+                        """)
+                }
+                TargetStorageKind.MEMORY -> {
+                    storeByteViaRegisterAInMemoryAddress(address.toHex(), target.memory!!)
+                }
+                TargetStorageKind.ARRAY -> {
+                    throw AssemblyError("no asm gen for assign memory byte at $address to array ${target.asmVarname}")
+                }
+                TargetStorageKind.REGISTER -> when(target.register!!) {
+                    RegisterOrPair.A -> asmgen.out("  lda  ${address.toHex()}")
+                    RegisterOrPair.X -> asmgen.out("  ldx  ${address.toHex()}")
+                    RegisterOrPair.Y -> asmgen.out("  ldy  ${address.toHex()}")
+                    else -> throw AssemblyError("can't assign byte to word register apir")
+                }
+                TargetStorageKind.STACK -> {
+                    asmgen.out("""
+                        lda  ${address.toHex()}
+                        sta  P8ESTACK_LO,x
+                        dex""")
+                }
+            }
+        } else if (identifier != null) {
+            when(target.kind) {
+                TargetStorageKind.VARIABLE -> {
+                    asmgen.loadByteFromPointerIntoA(identifier)
+                    asmgen.out(" sta  ${target.asmVarname}")
+                }
+                TargetStorageKind.MEMORY -> {
+                    val sourceName = asmgen.asmVariableName(identifier)
+                    storeByteViaRegisterAInMemoryAddress(sourceName, target.memory!!)
+                }
+                TargetStorageKind.ARRAY -> {
+                    throw AssemblyError("no asm gen for assign memory byte $identifier to array ${target.asmVarname} ")
+                }
+                TargetStorageKind.REGISTER -> {
+                    asmgen.loadByteFromPointerIntoA(identifier)
+                    when(target.register!!) {
+                        RegisterOrPair.A -> {}
+                        RegisterOrPair.X -> asmgen.out("  tax")
+                        RegisterOrPair.Y -> asmgen.out("  tay")
+                        else -> throw AssemblyError("can't assign byte to word register apir")
+                    }
+                }
+                TargetStorageKind.STACK -> {
+                    asmgen.loadByteFromPointerIntoA(identifier)
+                    asmgen.out(" sta  P8ESTACK_LO,x |  dex")
+                }
+            }
+        }
+    }
+
+    private fun storeByteViaRegisterAInMemoryAddress(ldaInstructionArg: String, memoryAddress: DirectMemoryWrite) {
+        val addressExpr = memoryAddress.addressExpression
+        val addressLv = addressExpr as? NumericLiteralValue
+        when {
+            addressLv != null -> {
+                asmgen.out("  lda $ldaInstructionArg |  sta  ${addressLv.number.toHex()}")
+            }
+            addressExpr is IdentifierReference -> {
+                asmgen.storeByteIntoPointer(addressExpr, ldaInstructionArg)
+            }
+            else -> {
+                asmgen.translateExpression(addressExpr)
+                asmgen.out("""
+                    inx
+                    lda  P8ESTACK_LO,x
+                    sta  P8ZP_SCRATCH_W2
+                    lda  P8ESTACK_HI,x
+                    sta  P8ZP_SCRATCH_W2+1
+                    lda  $ldaInstructionArg
+                    ldy  #0
+                    sta  (P8ZP_SCRATCH_W2),y""")
+            }
+        }
+    }
+
+    private fun storeRegisterInMemoryAddress(register: CpuRegister, memoryAddress: DirectMemoryWrite) {
+        // this is optimized for register A.
+        val addressExpr = memoryAddress.addressExpression
+        val addressLv = addressExpr as? NumericLiteralValue
+        val registerName = register.name.toLowerCase()
+        when {
+            addressLv != null -> {
+                asmgen.out("  st$registerName  ${addressLv.number.toHex()}")
+            }
+            addressExpr is IdentifierReference -> {
+                when (register) {
+                    CpuRegister.A -> {}
+                    CpuRegister.X -> asmgen.out(" txa")
+                    CpuRegister.Y -> asmgen.out(" tya")
+                }
+                asmgen.storeByteIntoPointer(addressExpr, null)
+            }
+            else -> {
+                asmgen.saveRegister(register)
+                asmgen.translateExpression(addressExpr)
+                asmgen.restoreRegister(CpuRegister.A)
+                asmgen.out("""
+                    inx
+                    ldy  P8ESTACK_LO,x
+                    sty  P8ZP_SCRATCH_W2
+                    ldy  P8ESTACK_HI,x
+                    sty  P8ZP_SCRATCH_W2+1
+                    ldy  #0
+                    sta  (P8ZP_SCRATCH_W2),y""")
+            }
+        }
+    }
+
+    private fun popAndWriteArrayvalueWithUnscaledIndexA(elementDt: DataType, asmArrayvarname: String) {
+        when (elementDt) {
+            in ByteDatatypes ->
+                asmgen.out("  tay |  inx |  lda  P8ESTACK_LO,x  | sta  $asmArrayvarname,y")
+            in WordDatatypes ->
+                asmgen.out("  asl  a |  tay |  inx |  lda  P8ESTACK_LO,x |  sta  $asmArrayvarname,y |  lda  P8ESTACK_HI,x |  sta $asmArrayvarname+1,y")
+            DataType.FLOAT ->
+                // scaling * 5 is done in the subroutine that's called
+                asmgen.out("""
+                    sta  P8ESTACK_LO,x
+                    dex
+                    lda  #<$asmArrayvarname
+                    ldy  #>$asmArrayvarname
+                    jsr  c64flt.pop_float_to_indexed_var
+                """)
+            else ->
+                throw AssemblyError("weird array type")
+        }
+    }
+}

compiler/src/prog8/compiler/target/cx16/CX16MachineDefinition.kt

@@ -0,0 +1,124 @@
+package prog8.compiler.target.cx16
+
+import prog8.ast.Program
+import prog8.compiler.*
+import prog8.compiler.target.IMachineDefinition
+import prog8.compiler.target.c64.C64MachineDefinition
+import prog8.parser.ModuleImporter
+import java.io.IOException
+
+internal object CX16MachineDefinition: IMachineDefinition {
+
+    override val cpu = "65c02"
+
+    // 5-byte cbm MFLPT format limitations:
+    override val FLOAT_MAX_POSITIVE = 1.7014118345e+38         // bytes: 255,127,255,255,255
+    override val FLOAT_MAX_NEGATIVE = -1.7014118345e+38        // bytes: 255,255,255,255,255
+    override val FLOAT_MEM_SIZE = 5
+    override val POINTER_MEM_SIZE = 2
+    override val BASIC_LOAD_ADDRESS = 0x0801
+    override val RAW_LOAD_ADDRESS = 0x8000
+
+    // the 2*256 byte evaluation stack (on which bytes, words, and even floats are stored during calculations)
+    // and some heavily used string constants derived from the two values above
+    override val ESTACK_LO = 0x0400        //  $0400-$04ff inclusive
+    override val ESTACK_HI = 0x0500        //  $0500-$05ff inclusive
+
+    override lateinit var zeropage: Zeropage
+    override val initSystemProcname = "cx16.init_system"
+
+    override fun getFloat(num: Number) = C64MachineDefinition.Mflpt5.fromNumber(num)
+
+    override fun getFloatRomConst(number: Double): String? = null       // TODO Does Cx16 have ROM float locations?
+    override fun importLibs(compilerOptions: CompilationOptions, importer: ModuleImporter, program: Program) {
+        if (compilerOptions.launcher == LauncherType.BASIC || compilerOptions.output == OutputType.PRG)
+            importer.importLibraryModule(program, "cx16lib")
+    }
+
+    override fun launchEmulator(programName: String) {
+        for(emulator in listOf("x16emu")) {
+            println("\nStarting Commander X16 emulator $emulator...")
+            val cmdline = listOf(emulator, "-rom", "/usr/share/x16-rom/rom.bin", "-scale", "2",
+                    "-run", "-prg", programName + ".prg")
+            val processb = ProcessBuilder(cmdline).inheritIO()
+            val process: Process
+            try {
+                process=processb.start()
+            } catch(x: IOException) {
+                continue  // try the next emulator executable
+            }
+            process.waitFor()
+            break
+        }
+    }
+
+    override fun initializeZeropage(compilerOptions: CompilationOptions) {
+        zeropage = CX16Zeropage(compilerOptions)
+    }
+
+    // 6502 opcodes (including aliases and illegal opcodes), these cannot be used as variable or label names
+    // TODO add 65C02 opcodes
+    override val opcodeNames = setOf("adc", "ahx", "alr", "anc", "and", "ane", "arr", "asl", "asr", "axs", "bcc", "bcs",
+            "beq", "bge", "bit", "blt", "bmi", "bne", "bpl", "brk", "bvc", "bvs", "clc",
+            "cld", "cli", "clv", "cmp", "cpx", "cpy", "dcm", "dcp", "dec", "dex", "dey",
+            "eor", "gcc", "gcs", "geq", "gge", "glt", "gmi", "gne", "gpl", "gvc", "gvs",
+            "inc", "ins", "inx", "iny", "isb", "isc", "jam", "jmp", "jsr", "lae", "las",
+            "lax", "lda", "lds", "ldx", "ldy", "lsr", "lxa", "nop", "ora", "pha", "php",
+            "pla", "plp", "rla", "rol", "ror", "rra", "rti", "rts", "sax", "sbc", "sbx",
+            "sec", "sed", "sei", "sha", "shl", "shr", "shs", "shx", "shy", "slo", "sre",
+            "sta", "stx", "sty", "tas", "tax", "tay", "tsx", "txa", "txs", "tya", "xaa")
+
+
+    internal class CX16Zeropage(options: CompilationOptions) : Zeropage(options) {
+
+        override val SCRATCH_B1 = 0x79      // temp storage for a single byte
+        override val SCRATCH_REG = 0x7a     // temp storage for a register
+        override val SCRATCH_REG_X = 0x7b   // temp storage for register X (the evaluation stack pointer)
+        override val SCRATCH_W1 = 0x7c      // temp storage 1 for a word  $7c+$7d
+        override val SCRATCH_W2 = 0x7e      // temp storage 2 for a word  $7e+$7f
+
+
+        override val exitProgramStrategy: ExitProgramStrategy = when (options.zeropage) {
+            ZeropageType.BASICSAFE, ZeropageType.DONTUSE -> ExitProgramStrategy.CLEAN_EXIT
+            ZeropageType.KERNALSAFE, ZeropageType.FULL -> ExitProgramStrategy.SYSTEM_RESET
+            else -> ExitProgramStrategy.SYSTEM_RESET
+        }
+
+
+        init {
+            if (options.floats && options.zeropage !in setOf(ZeropageType.BASICSAFE, ZeropageType.DONTUSE ))
+                throw CompilerException("when floats are enabled, zero page type should be 'basicsafe' or 'dontuse'")
+
+            // the addresses 0x02 to 0x21 (inclusive) are taken for sixteen virtual 16-bit api registers.
+
+            when (options.zeropage) {
+                ZeropageType.FULL -> {
+                    free.addAll(0x22..0xff)
+                    free.removeAll(listOf(SCRATCH_B1, SCRATCH_REG, SCRATCH_REG_X, SCRATCH_W1, SCRATCH_W1 + 1, SCRATCH_W2, SCRATCH_W2 + 1))
+                }
+                ZeropageType.KERNALSAFE -> {
+                    free.addAll(0x22..0x7f)
+                    free.addAll(0xa9..0xff)
+                    free.removeAll(listOf(SCRATCH_B1, SCRATCH_REG, SCRATCH_REG_X, SCRATCH_W1, SCRATCH_W1 + 1, SCRATCH_W2, SCRATCH_W2 + 1))
+                }
+                ZeropageType.BASICSAFE -> {
+                    free.addAll(0x22..0x7f)
+                    free.removeAll(listOf(SCRATCH_B1, SCRATCH_REG, SCRATCH_REG_X, SCRATCH_W1, SCRATCH_W1 + 1, SCRATCH_W2, SCRATCH_W2 + 1))
+                }
+                ZeropageType.DONTUSE -> {
+                    free.clear() // don't use zeropage at all
+                }
+                else -> throw CompilerException("for this machine target, zero page type 'floatsafe' is not available. ${options.zeropage}")
+            }
+
+            require(SCRATCH_B1 !in free)
+            require(SCRATCH_REG !in free)
+            require(SCRATCH_REG_X !in free)
+            require(SCRATCH_W1 !in free)
+            require(SCRATCH_W2 !in free)
+
+            for (reserved in options.zpReserved)
+                reserve(reserved)
+        }
+    }
+}

compiler/src/prog8/functions/BuiltinFunctions.kt

@@ -1,416 +1,427 @@
 package prog8.functions
 
-import prog8.ast.*
+import prog8.ast.Program
+import prog8.ast.base.*
+import prog8.ast.expressions.*
+import prog8.ast.statements.StructDecl
+import prog8.ast.statements.VarDecl
 import prog8.compiler.CompilerException
-import prog8.compiler.HeapValues
+import kotlin.math.*
-import kotlin.math.PI
-import kotlin.math.cos
-import kotlin.math.log2
-import kotlin.math.sin
 
 
-class BuiltinFunctionParam(val name: String, val possibleDatatypes: Set<DataType>)
+class FParam(val name: String, val possibleDatatypes: Set<DataType>)
 
-class FunctionSignature(val pure: Boolean,      // does it have side effects?
+
-                        val parameters: List<BuiltinFunctionParam>,
+typealias ConstExpressionCaller = (args: List<Expression>, position: Position, program: Program) -> NumericLiteralValue
-                        val returntype: DataType?,
+
-                        val constExpressionFunc: ((args: List<IExpression>, position: Position, namespace: INameScope, heap: HeapValues) -> LiteralValue)? = null)
+
+class FSignature(val pure: Boolean,      // does it have side effects?
+                 val parameters: List<FParam>,
+                 val returntype: DataType?,
+                 val constExpressionFunc: ConstExpressionCaller? = null)
 
 
 val BuiltinFunctions = mapOf(
         // this set of function have no return value and operate in-place:
-    "rol"         to FunctionSignature(false, listOf(BuiltinFunctionParam("item", setOf(DataType.UBYTE, DataType.UWORD))), null),
+    "rol"         to FSignature(false, listOf(FParam("item", setOf(DataType.UBYTE, DataType.UWORD))), null),
-    "ror"         to FunctionSignature(false, listOf(BuiltinFunctionParam("item", setOf(DataType.UBYTE, DataType.UWORD))), null),
+    "ror"         to FSignature(false, listOf(FParam("item", setOf(DataType.UBYTE, DataType.UWORD))), null),
-    "rol2"        to FunctionSignature(false, listOf(BuiltinFunctionParam("item", setOf(DataType.UBYTE, DataType.UWORD))), null),
+    "rol2"        to FSignature(false, listOf(FParam("item", setOf(DataType.UBYTE, DataType.UWORD))), null),
-    "ror2"        to FunctionSignature(false, listOf(BuiltinFunctionParam("item", setOf(DataType.UBYTE, DataType.UWORD))), null),
+    "ror2"        to FSignature(false, listOf(FParam("item", setOf(DataType.UBYTE, DataType.UWORD))), null),
-    "lsl"         to FunctionSignature(false, listOf(BuiltinFunctionParam("item", IntegerDatatypes)), null),
+    "sort"        to FSignature(false, listOf(FParam("array", ArrayDatatypes)), null),
-    "lsr"         to FunctionSignature(false, listOf(BuiltinFunctionParam("item", IntegerDatatypes)), null),
+    "reverse"     to FSignature(false, listOf(FParam("array", ArrayDatatypes)), null),
         // these few have a return value depending on the argument(s):
-    "max"         to FunctionSignature(true, listOf(BuiltinFunctionParam("values", ArrayDatatypes)), null) { a, p, n, h -> collectionArgOutputNumber(a, p, n, h) { it.max()!! }},        // type depends on args
+    "max"         to FSignature(true, listOf(FParam("values", ArrayDatatypes)), null) { a, p, prg -> collectionArg(a, p, prg, ::builtinMax) },    // type depends on args
-    "min"         to FunctionSignature(true, listOf(BuiltinFunctionParam("values", ArrayDatatypes)), null) { a, p, n, h -> collectionArgOutputNumber(a, p, n, h) { it.min()!! }},        // type depends on args
+    "min"         to FSignature(true, listOf(FParam("values", ArrayDatatypes)), null) { a, p, prg -> collectionArg(a, p, prg, ::builtinMin) },    // type depends on args
-    "sum"         to FunctionSignature(true, listOf(BuiltinFunctionParam("values", ArrayDatatypes)), null) { a, p, n, h -> collectionArgOutputNumber(a, p, n, h) { it.sum() }},        // type depends on args
+    "sum"         to FSignature(true, listOf(FParam("values", ArrayDatatypes)), null) { a, p, prg -> collectionArg(a, p, prg, ::builtinSum) },      // type depends on args
-    "abs"         to FunctionSignature(true, listOf(BuiltinFunctionParam("value", NumericDatatypes)), null, ::builtinAbs),      // type depends on argument
+    "abs"         to FSignature(true, listOf(FParam("value", NumericDatatypes)), null, ::builtinAbs),      // type depends on argument
+    "len"         to FSignature(true, listOf(FParam("values", IterableDatatypes)), null, ::builtinLen),    // type is UBYTE or UWORD depending on actual length
+    "sizeof"      to FSignature(true, listOf(FParam("object", DataType.values().toSet())), DataType.UBYTE, ::builtinSizeof),
         // normal functions follow:
-    "sin"         to FunctionSignature(true, listOf(BuiltinFunctionParam("rads", setOf(DataType.FLOAT))), DataType.FLOAT) { a, p, n, h -> oneDoubleArg(a, p, n, h, Math::sin) },
+    "sgn"         to FSignature(true, listOf(FParam("value", NumericDatatypes)), DataType.BYTE, ::builtinSgn ),
-    "sin8"        to FunctionSignature(true, listOf(BuiltinFunctionParam("angle8", setOf(DataType.UBYTE))), DataType.BYTE, ::builtinSin8 ),
+    "sin"         to FSignature(true, listOf(FParam("rads", setOf(DataType.FLOAT))), DataType.FLOAT) { a, p, prg -> oneDoubleArg(a, p, prg, Math::sin) },
-    "sin8u"       to FunctionSignature(true, listOf(BuiltinFunctionParam("angle8", setOf(DataType.UBYTE))), DataType.UBYTE, ::builtinSin8u ),
+    "sin8"        to FSignature(true, listOf(FParam("angle8", setOf(DataType.UBYTE))), DataType.BYTE, ::builtinSin8 ),
-    "sin16"       to FunctionSignature(true, listOf(BuiltinFunctionParam("angle8", setOf(DataType.UBYTE))), DataType.WORD, ::builtinSin16 ),
+    "sin8u"       to FSignature(true, listOf(FParam("angle8", setOf(DataType.UBYTE))), DataType.UBYTE, ::builtinSin8u ),
-    "sin16u"      to FunctionSignature(true, listOf(BuiltinFunctionParam("angle8", setOf(DataType.UBYTE))), DataType.UWORD, ::builtinSin16u ),
+    "sin16"       to FSignature(true, listOf(FParam("angle8", setOf(DataType.UBYTE))), DataType.WORD, ::builtinSin16 ),
-    "cos"         to FunctionSignature(true, listOf(BuiltinFunctionParam("rads", setOf(DataType.FLOAT))), DataType.FLOAT) { a, p, n, h -> oneDoubleArg(a, p, n, h, Math::cos) },
+    "sin16u"      to FSignature(true, listOf(FParam("angle8", setOf(DataType.UBYTE))), DataType.UWORD, ::builtinSin16u ),
-    "cos8"        to FunctionSignature(true, listOf(BuiltinFunctionParam("angle8", setOf(DataType.UBYTE))), DataType.BYTE, ::builtinCos8 ),
+    "cos"         to FSignature(true, listOf(FParam("rads", setOf(DataType.FLOAT))), DataType.FLOAT) { a, p, prg -> oneDoubleArg(a, p, prg, Math::cos) },
-    "cos8u"       to FunctionSignature(true, listOf(BuiltinFunctionParam("angle8", setOf(DataType.UBYTE))), DataType.UBYTE, ::builtinCos8u ),
+    "cos8"        to FSignature(true, listOf(FParam("angle8", setOf(DataType.UBYTE))), DataType.BYTE, ::builtinCos8 ),
-    "cos16"       to FunctionSignature(true, listOf(BuiltinFunctionParam("angle8", setOf(DataType.UBYTE))), DataType.WORD, ::builtinCos16 ),
+    "cos8u"       to FSignature(true, listOf(FParam("angle8", setOf(DataType.UBYTE))), DataType.UBYTE, ::builtinCos8u ),
-    "cos16u"      to FunctionSignature(true, listOf(BuiltinFunctionParam("angle8", setOf(DataType.UBYTE))), DataType.UWORD, ::builtinCos16u ),
+    "cos16"       to FSignature(true, listOf(FParam("angle8", setOf(DataType.UBYTE))), DataType.WORD, ::builtinCos16 ),
-    "tan"         to FunctionSignature(true, listOf(BuiltinFunctionParam("rads", setOf(DataType.FLOAT))), DataType.FLOAT) { a, p, n, h -> oneDoubleArg(a, p, n, h, Math::tan) },
+    "cos16u"      to FSignature(true, listOf(FParam("angle8", setOf(DataType.UBYTE))), DataType.UWORD, ::builtinCos16u ),
-    "atan"        to FunctionSignature(true, listOf(BuiltinFunctionParam("rads", setOf(DataType.FLOAT))), DataType.FLOAT) { a, p, n, h -> oneDoubleArg(a, p, n, h, Math::atan) },
+    "tan"         to FSignature(true, listOf(FParam("rads", setOf(DataType.FLOAT))), DataType.FLOAT) { a, p, prg -> oneDoubleArg(a, p, prg, Math::tan) },
-    "ln"          to FunctionSignature(true, listOf(BuiltinFunctionParam("value", setOf(DataType.FLOAT))), DataType.FLOAT) { a, p, n, h -> oneDoubleArg(a, p, n, h, Math::log) },
+    "atan"        to FSignature(true, listOf(FParam("rads", setOf(DataType.FLOAT))), DataType.FLOAT) { a, p, prg -> oneDoubleArg(a, p, prg, Math::atan) },
-    "log2"        to FunctionSignature(true, listOf(BuiltinFunctionParam("value", setOf(DataType.FLOAT))), DataType.FLOAT) { a, p, n, h -> oneDoubleArg(a, p, n, h, ::log2) },
+    "ln"          to FSignature(true, listOf(FParam("value", setOf(DataType.FLOAT))), DataType.FLOAT) { a, p, prg -> oneDoubleArg(a, p, prg, Math::log) },
-        // TODO: sqrt() should have integer versions too
+    "log2"        to FSignature(true, listOf(FParam("value", setOf(DataType.FLOAT))), DataType.FLOAT) { a, p, prg -> oneDoubleArg(a, p, prg, ::log2) },
-    "sqrt"        to FunctionSignature(true, listOf(BuiltinFunctionParam("value", setOf(DataType.FLOAT))), DataType.FLOAT) { a, p, n, h -> oneDoubleArg(a, p, n, h, Math::sqrt) },
+    "sqrt16"      to FSignature(true, listOf(FParam("value", setOf(DataType.UWORD))), DataType.UBYTE) { a, p, prg -> oneIntArgOutputInt(a, p, prg) { sqrt(it.toDouble()).toInt() } },
-    "rad"         to FunctionSignature(true, listOf(BuiltinFunctionParam("value", setOf(DataType.FLOAT))), DataType.FLOAT) { a, p, n, h -> oneDoubleArg(a, p, n, h, Math::toRadians) },
+    "sqrt"        to FSignature(true, listOf(FParam("value", setOf(DataType.FLOAT))), DataType.FLOAT) { a, p, prg -> oneDoubleArg(a, p, prg, Math::sqrt) },
-    "deg"         to FunctionSignature(true, listOf(BuiltinFunctionParam("value", setOf(DataType.FLOAT))), DataType.FLOAT) { a, p, n, h -> oneDoubleArg(a, p, n, h, Math::toDegrees) },
+    "rad"         to FSignature(true, listOf(FParam("value", setOf(DataType.FLOAT))), DataType.FLOAT) { a, p, prg -> oneDoubleArg(a, p, prg, Math::toRadians) },
-    "avg"         to FunctionSignature(true, listOf(BuiltinFunctionParam("values", ArrayDatatypes)), DataType.FLOAT, ::builtinAvg),
+    "deg"         to FSignature(true, listOf(FParam("value", setOf(DataType.FLOAT))), DataType.FLOAT) { a, p, prg -> oneDoubleArg(a, p, prg, Math::toDegrees) },
-    "round"       to FunctionSignature(true, listOf(BuiltinFunctionParam("value", setOf(DataType.FLOAT))), DataType.FLOAT) { a, p, n, h -> oneDoubleArgOutputWord(a, p, n, h, Math::round) },
+    "round"       to FSignature(true, listOf(FParam("value", setOf(DataType.FLOAT))), DataType.FLOAT) { a, p, prg -> oneDoubleArgOutputWord(a, p, prg, Math::round) },
-    "floor"       to FunctionSignature(true, listOf(BuiltinFunctionParam("value", setOf(DataType.FLOAT))), DataType.FLOAT) { a, p, n, h -> oneDoubleArgOutputWord(a, p, n, h, Math::floor) },
+    "floor"       to FSignature(true, listOf(FParam("value", setOf(DataType.FLOAT))), DataType.FLOAT) { a, p, prg -> oneDoubleArgOutputWord(a, p, prg, Math::floor) },
-    "ceil"        to FunctionSignature(true, listOf(BuiltinFunctionParam("value", setOf(DataType.FLOAT))), DataType.FLOAT) { a, p, n, h -> oneDoubleArgOutputWord(a, p, n, h, Math::ceil) },
+    "ceil"        to FSignature(true, listOf(FParam("value", setOf(DataType.FLOAT))), DataType.FLOAT) { a, p, prg -> oneDoubleArgOutputWord(a, p, prg, Math::ceil) },
-    "len"         to FunctionSignature(true, listOf(BuiltinFunctionParam("values", IterableDatatypes)), DataType.UWORD, ::builtinLen),
+    "any"         to FSignature(true, listOf(FParam("values", ArrayDatatypes)), DataType.UBYTE) { a, p, prg -> collectionArg(a, p, prg, ::builtinAny) },
-    "any"         to FunctionSignature(true, listOf(BuiltinFunctionParam("values", ArrayDatatypes)), DataType.UBYTE) { a, p, n, h -> collectionArgOutputBoolean(a, p, n, h) { it.any { v -> v != 0.0} }},
+    "all"         to FSignature(true, listOf(FParam("values", ArrayDatatypes)), DataType.UBYTE) { a, p, prg -> collectionArg(a, p, prg, ::builtinAll) },
-    "all"         to FunctionSignature(true, listOf(BuiltinFunctionParam("values", ArrayDatatypes)), DataType.UBYTE) { a, p, n, h -> collectionArgOutputBoolean(a, p, n, h) { it.all { v -> v != 0.0} }},
+    "lsb"         to FSignature(true, listOf(FParam("value", setOf(DataType.UWORD, DataType.WORD))), DataType.UBYTE) { a, p, prg -> oneIntArgOutputInt(a, p, prg) { x: Int -> x and 255 }},
-    "lsb"         to FunctionSignature(true, listOf(BuiltinFunctionParam("value", setOf(DataType.UWORD, DataType.WORD))), DataType.UBYTE) { a, p, n, h -> oneIntArgOutputInt(a, p, n, h) { x: Int -> x and 255 }},
+    "msb"         to FSignature(true, listOf(FParam("value", setOf(DataType.UWORD, DataType.WORD))), DataType.UBYTE) { a, p, prg -> oneIntArgOutputInt(a, p, prg) { x: Int -> x ushr 8 and 255}},
-    "msb"         to FunctionSignature(true, listOf(BuiltinFunctionParam("value", setOf(DataType.UWORD, DataType.WORD))), DataType.UBYTE) { a, p, n, h -> oneIntArgOutputInt(a, p, n, h) { x: Int -> x ushr 8 and 255}},
+    "mkword"      to FSignature(true, listOf(FParam("msb", setOf(DataType.UBYTE)), FParam("lsb", setOf(DataType.UBYTE))), DataType.UWORD, ::builtinMkword),
-    "mkword"      to FunctionSignature(true, listOf(
+    "rnd"         to FSignature(true, emptyList(), DataType.UBYTE),
-                                                        BuiltinFunctionParam("lsb", setOf(DataType.UBYTE)),
+    "rndw"        to FSignature(true, emptyList(), DataType.UWORD),
-                                                        BuiltinFunctionParam("msb", setOf(DataType.UBYTE))), DataType.UWORD, ::builtinMkword),
+    "rndf"        to FSignature(true, emptyList(), DataType.FLOAT),
-    "rnd"         to FunctionSignature(true, emptyList(), DataType.UBYTE),
+    "exit"        to FSignature(false, listOf(FParam("returnvalue", setOf(DataType.UBYTE))), null),
-    "rndw"        to FunctionSignature(true, emptyList(), DataType.UWORD),
+    "rsave"       to FSignature(false, emptyList(), null),
-    "rndf"        to FunctionSignature(true, emptyList(), DataType.FLOAT),
+    "rrestore"    to FSignature(false, emptyList(), null),
-    "rsave"       to FunctionSignature(false, emptyList(), null),
+    "set_carry"   to FSignature(false, emptyList(), null),
-    "rrestore"    to FunctionSignature(false, emptyList(), null),
+    "clear_carry" to FSignature(false, emptyList(), null),
-    "set_carry"   to FunctionSignature(false, emptyList(), null),
+    "set_irqd"    to FSignature(false, emptyList(), null),
-    "clear_carry" to FunctionSignature(false, emptyList(), null),
+    "clear_irqd"  to FSignature(false, emptyList(), null),
-    "set_irqd"    to FunctionSignature(false, emptyList(), null),
+    "read_flags"  to FSignature(false, emptyList(), DataType.UBYTE),
-    "clear_irqd"  to FunctionSignature(false, emptyList(), null),
+    "swap"        to FSignature(false, listOf(FParam("first", NumericDatatypes), FParam("second", NumericDatatypes)), null),
-    "swap"        to FunctionSignature(false, listOf(BuiltinFunctionParam("first", NumericDatatypes), BuiltinFunctionParam("second", NumericDatatypes)), null),
+    "memcopy"     to FSignature(false, listOf(
-    "memcopy"     to FunctionSignature(false, listOf(
+                            FParam("from", IterableDatatypes + DataType.UWORD),
-                                                        BuiltinFunctionParam("from", IterableDatatypes + setOf(DataType.UWORD)),
+                            FParam("to", IterableDatatypes + DataType.UWORD),
-                                                        BuiltinFunctionParam("to", IterableDatatypes + setOf(DataType.UWORD)),
+                            FParam("numbytes", setOf(DataType.UBYTE))), null),
-                                                        BuiltinFunctionParam("numbytes", IntegerDatatypes)), null),
+    "memset"      to FSignature(false, listOf(
-    "memset"      to FunctionSignature(false, listOf(
+                            FParam("address", IterableDatatypes + DataType.UWORD),
-                                                        BuiltinFunctionParam("address", IterableDatatypes + setOf(DataType.UWORD)),
+                            FParam("numbytes", setOf(DataType.UWORD)),
-                                                        BuiltinFunctionParam("numbytes", setOf(DataType.UWORD)),
+                            FParam("bytevalue", ByteDatatypes)), null),
-                                                        BuiltinFunctionParam("bytevalue", setOf(DataType.UBYTE, DataType.BYTE))), null),
+    "memsetw"     to FSignature(false, listOf(
-    "memsetw"     to FunctionSignature(false, listOf(
+                            FParam("address", IterableDatatypes + DataType.UWORD),
-                                                        BuiltinFunctionParam("address", IterableDatatypes + setOf(DataType.UWORD)),
+                            FParam("numwords", setOf(DataType.UWORD)),
-                                                        BuiltinFunctionParam("numwords", setOf(DataType.UWORD)),
+                            FParam("wordvalue", setOf(DataType.UWORD, DataType.WORD))), null),
-                                                        BuiltinFunctionParam("wordvalue", setOf(DataType.UWORD, DataType.WORD))), null),
+    "strlen"      to FSignature(true, listOf(FParam("string", setOf(DataType.STR))), DataType.UBYTE, ::builtinStrlen),
-    "vm_write_memchr"  to FunctionSignature(false, listOf(BuiltinFunctionParam("address", setOf(DataType.UWORD))), null),
+    "substr"      to FSignature(false, listOf(
-    "vm_write_memstr"  to FunctionSignature(false, listOf(BuiltinFunctionParam("address", setOf(DataType.UWORD))), null),
+            FParam("source", IterableDatatypes + DataType.UWORD),
-    "vm_write_num"     to FunctionSignature(false, listOf(BuiltinFunctionParam("number", NumericDatatypes)), null),
+            FParam("target", IterableDatatypes + DataType.UWORD),
-    "vm_write_char"    to FunctionSignature(false, listOf(BuiltinFunctionParam("char", setOf(DataType.UBYTE))), null),
+            FParam("start", setOf(DataType.UBYTE)),
-    "vm_write_str"     to FunctionSignature(false, listOf(BuiltinFunctionParam("string", StringDatatypes)), null),
+            FParam("length", setOf(DataType.UBYTE))), null),
-    "vm_input_str"     to FunctionSignature(false, listOf(BuiltinFunctionParam("intovar", StringDatatypes)), null),
+    "leftstr"      to FSignature(false, listOf(
-    "vm_gfx_clearscr"  to FunctionSignature(false, listOf(BuiltinFunctionParam("color", setOf(DataType.UBYTE))), null),
+            FParam("source", IterableDatatypes + DataType.UWORD),
-    "vm_gfx_pixel"     to FunctionSignature(false, listOf(
+            FParam("target", IterableDatatypes + DataType.UWORD),
-                                                        BuiltinFunctionParam("x", IntegerDatatypes),
+            FParam("length", setOf(DataType.UBYTE))), null),
-                                                        BuiltinFunctionParam("y", IntegerDatatypes),
+    "rightstr"      to FSignature(false, listOf(
-                                                        BuiltinFunctionParam("color", IntegerDatatypes)), null),
+            FParam("source", IterableDatatypes + DataType.UWORD),
-    "vm_gfx_line"     to FunctionSignature(false, listOf(
+            FParam("target", IterableDatatypes + DataType.UWORD),
-                                                        BuiltinFunctionParam("x1", IntegerDatatypes),
+            FParam("length", setOf(DataType.UBYTE))), null)
-                                                        BuiltinFunctionParam("y1", IntegerDatatypes),
-                                                        BuiltinFunctionParam("x2", IntegerDatatypes),
-                                                        BuiltinFunctionParam("y2", IntegerDatatypes),
-                                                        BuiltinFunctionParam("color", IntegerDatatypes)), null),
-    "vm_gfx_text"      to FunctionSignature(false, listOf(
-                                                        BuiltinFunctionParam("x", IntegerDatatypes),
-                                                        BuiltinFunctionParam("y", IntegerDatatypes),
-                                                        BuiltinFunctionParam("color", IntegerDatatypes),
-                                                        BuiltinFunctionParam("text", StringDatatypes)),
-                                                        null)
 )
 
+fun builtinMax(array: List<Number>): Number = array.maxByOrNull { it.toDouble() }!!
 
-fun builtinFunctionReturnType(function: String, args: List<IExpression>, namespace: INameScope, heap: HeapValues): DataType? {
+fun builtinMin(array: List<Number>): Number = array.minByOrNull { it.toDouble() }!!
 
-    fun datatypeFromListArg(arglist: IExpression): DataType {
+fun builtinSum(array: List<Number>): Number = array.sumByDouble { it.toDouble() }
-        if(arglist is LiteralValue) {
+
-            if(arglist.type==DataType.ARRAY_UB || arglist.type==DataType.ARRAY_UW || arglist.type==DataType.ARRAY_F) {
+fun builtinAny(array: List<Number>): Number = if(array.any { it.toDouble()!=0.0 }) 1 else 0
-                val dt = arglist.arrayvalue!!.map {it.resultingDatatype(namespace, heap)}
+
-                if(dt.any { it!=DataType.UBYTE && it!=DataType.UWORD && it!=DataType.FLOAT}) {
+fun builtinAll(array: List<Number>): Number = if(array.all { it.toDouble()!=0.0 }) 1 else 0
-                    throw FatalAstException("fuction $function only accepts arrayspec of numeric values")
+
-                }
+
-                if(dt.any { it==DataType.FLOAT }) return DataType.FLOAT
+fun builtinFunctionReturnType(function: String, args: List<Expression>, program: Program): InferredTypes.InferredType {
-                if(dt.any { it==DataType.UWORD }) return DataType.UWORD
+
-                return DataType.UBYTE
+    fun datatypeFromIterableArg(arglist: Expression): DataType {
+        if(arglist is ArrayLiteralValue) {
+            val dt = arglist.value.map {it.inferType(program).typeOrElse(DataType.STRUCT)}.toSet()
+            if(dt.any { it !in NumericDatatypes }) {
+                throw FatalAstException("fuction $function only accepts array of numeric values")
             }
+            if(DataType.FLOAT in dt) return DataType.FLOAT
+            if(DataType.UWORD in dt) return DataType.UWORD
+            if(DataType.WORD in dt) return DataType.WORD
+            if(DataType.BYTE in dt) return DataType.BYTE
+            return DataType.UBYTE
         }
         if(arglist is IdentifierReference) {
-            val dt = arglist.resultingDatatype(namespace, heap)
+            val idt = arglist.inferType(program)
-            return when(dt) {
+            if(!idt.isKnown)
-                DataType.UBYTE, DataType.BYTE, DataType.UWORD, DataType.WORD, DataType.FLOAT,
+                throw FatalAstException("couldn't determine type of iterable $arglist")
-                DataType.STR, DataType.STR_P, DataType.STR_S, DataType.STR_PS -> dt
+            return when(val dt = idt.typeOrElse(DataType.STRUCT)) {
-                DataType.ARRAY_UB -> DataType.UBYTE
+                DataType.STR, in NumericDatatypes -> dt
-                DataType.ARRAY_B -> DataType.BYTE
+                in ArrayDatatypes -> ArrayElementTypes.getValue(dt)
-                DataType.ARRAY_UW -> DataType.UWORD
+                else -> throw FatalAstException("function '$function' requires one argument which is an iterable")
-                DataType.ARRAY_W -> DataType.WORD
-                DataType.ARRAY_F -> DataType.FLOAT
-                null -> throw FatalAstException("function requires one argument which is an arrayspec $function")
             }
         }
-        throw FatalAstException("function requires one argument which is an arrayspec $function")
+        throw FatalAstException("function '$function' requires one argument which is an iterable")
     }
 
     val func = BuiltinFunctions.getValue(function)
     if(func.returntype!=null)
-        return func.returntype
+        return InferredTypes.knownFor(func.returntype)
     // function has return values, but the return type depends on the arguments
 
     return when (function) {
-        "max", "min", "abs" -> {
+        "abs" -> {
-            val dt = datatypeFromListArg(args.single())
+            val dt = args.single().inferType(program)
-            when(dt) {
+            if(dt.typeOrElse(DataType.STRUCT) in NumericDatatypes)
-                DataType.UBYTE, DataType.BYTE, DataType.UWORD, DataType.WORD, DataType.FLOAT -> dt
+                return dt
-                DataType.STR, DataType.STR_P, DataType.STR_S, DataType.STR_PS -> DataType.UBYTE
+            else
-                DataType.ARRAY_UB -> DataType.UBYTE
+                throw FatalAstException("weird datatype passed to abs $dt")
-                DataType.ARRAY_B -> DataType.BYTE
+        }
-                DataType.ARRAY_UW -> DataType.UWORD
+        "max", "min" -> {
-                DataType.ARRAY_W -> DataType.WORD
+            when(val dt = datatypeFromIterableArg(args.single())) {
-                DataType.ARRAY_F -> DataType.FLOAT
+                DataType.STR -> InferredTypes.knownFor(DataType.UBYTE)
+                in NumericDatatypes -> InferredTypes.knownFor(dt)
+                in ArrayDatatypes -> InferredTypes.knownFor(ArrayElementTypes.getValue(dt))
+                else -> InferredTypes.unknown()
             }
         }
         "sum" -> {
-            val dt=datatypeFromListArg(args.single())
+            when(datatypeFromIterableArg(args.single())) {
-            when(dt) {
+                DataType.UBYTE, DataType.UWORD -> InferredTypes.knownFor(DataType.UWORD)
-                DataType.UBYTE, DataType.UWORD -> DataType.UWORD
+                DataType.BYTE, DataType.WORD -> InferredTypes.knownFor(DataType.WORD)
-                DataType.BYTE, DataType.WORD -> DataType.WORD
+                DataType.FLOAT -> InferredTypes.knownFor(DataType.FLOAT)
-                DataType.FLOAT -> DataType.FLOAT
+                DataType.ARRAY_UB, DataType.ARRAY_UW -> InferredTypes.knownFor(DataType.UWORD)
-                DataType.ARRAY_UB, DataType.ARRAY_UW -> DataType.UWORD
+                DataType.ARRAY_B, DataType.ARRAY_W -> InferredTypes.knownFor(DataType.WORD)
-                DataType.ARRAY_B, DataType.ARRAY_W -> DataType.WORD
+                DataType.ARRAY_F -> InferredTypes.knownFor(DataType.FLOAT)
-                DataType.ARRAY_F -> DataType.FLOAT
+                DataType.STR -> InferredTypes.knownFor(DataType.UWORD)
-                DataType.STR, DataType.STR_P, DataType.STR_S, DataType.STR_PS -> DataType.UWORD
+                else -> InferredTypes.unknown()
             }
         }
-        else -> return null
+        "len" -> {
+            // a length can be >255 so in that case, the result is an UWORD instead of an UBYTE
+            // but to avoid a lot of code duplication we simply assume UWORD in all cases for now
+            return InferredTypes.knownFor(DataType.UWORD)
+        }
+        else -> return InferredTypes.unknown()
     }
 }
 
 
 class NotConstArgumentException: AstException("not a const argument to a built-in function")
+class CannotEvaluateException(func:String, msg: String): FatalAstException("cannot evaluate built-in function $func: $msg")
 
 
-private fun oneDoubleArg(args: List<IExpression>, position: Position, namespace:INameScope, heap: HeapValues, function: (arg: Double)->Number): LiteralValue {
+private fun oneDoubleArg(args: List<Expression>, position: Position, program: Program, function: (arg: Double)->Number): NumericLiteralValue {
     if(args.size!=1)
         throw SyntaxError("built-in function requires one floating point argument", position)
-    val constval = args[0].constValue(namespace, heap) ?: throw NotConstArgumentException()
+    val constval = args[0].constValue(program) ?: throw NotConstArgumentException()
-    if(constval.type!=DataType.FLOAT)
+    val float = constval.number.toDouble()
-        throw SyntaxError("built-in function requires one floating point argument", position)
-
-    val float = constval.asNumericValue?.toDouble()!!
     return numericLiteral(function(float), args[0].position)
 }
 
-private fun oneDoubleArgOutputWord(args: List<IExpression>, position: Position, namespace:INameScope, heap: HeapValues, function: (arg: Double)->Number): LiteralValue {
+private fun oneDoubleArgOutputWord(args: List<Expression>, position: Position, program: Program, function: (arg: Double)->Number): NumericLiteralValue {
     if(args.size!=1)
         throw SyntaxError("built-in function requires one floating point argument", position)
-    val constval = args[0].constValue(namespace, heap) ?: throw NotConstArgumentException()
+    val constval = args[0].constValue(program) ?: throw NotConstArgumentException()
-    if(constval.type!=DataType.FLOAT)
+    val float = constval.number.toDouble()
-        throw SyntaxError("built-in function requires one floating point argument", position)
+    return NumericLiteralValue(DataType.WORD, function(float).toInt(), args[0].position)
-    return LiteralValue(DataType.WORD, wordvalue=function(constval.asNumericValue!!.toDouble()).toInt(), position=args[0].position)
 }
 
-private fun oneIntArgOutputInt(args: List<IExpression>, position: Position, namespace:INameScope, heap: HeapValues, function: (arg: Int)->Number): LiteralValue {
+private fun oneIntArgOutputInt(args: List<Expression>, position: Position, program: Program, function: (arg: Int)->Number): NumericLiteralValue {
     if(args.size!=1)
         throw SyntaxError("built-in function requires one integer argument", position)
-    val constval = args[0].constValue(namespace, heap) ?: throw NotConstArgumentException()
+    val constval = args[0].constValue(program) ?: throw NotConstArgumentException()
-    if(constval.type!=DataType.UBYTE && constval.type!=DataType.UWORD)
+    if(constval.type != DataType.UBYTE && constval.type!= DataType.UWORD)
         throw SyntaxError("built-in function requires one integer argument", position)
 
-    val integer = constval.asNumericValue?.toInt()!!
+    val integer = constval.number.toInt()
     return numericLiteral(function(integer).toInt(), args[0].position)
 }
 
-private fun collectionArgOutputNumber(args: List<IExpression>, position: Position,
+private fun collectionArg(args: List<Expression>, position: Position, program: Program, function: (arg: List<Number>)->Number): NumericLiteralValue {
-                                      namespace:INameScope, heap: HeapValues,
-                                      function: (arg: Collection<Double>)->Number): LiteralValue {
     if(args.size!=1)
         throw SyntaxError("builtin function requires one non-scalar argument", position)
-    val iterable = args[0].constValue(namespace, heap) ?: throw NotConstArgumentException()
 
-    val result = if(iterable.arrayvalue != null) {
+    val array= args[0] as? ArrayLiteralValue ?: throw NotConstArgumentException()
-        val constants = iterable.arrayvalue.map { it.constValue(namespace, heap)?.asNumericValue }
+    val constElements = array.value.map{it.constValue(program)?.number}
-        if(null in constants)
+    if(constElements.contains(null))
-            throw NotConstArgumentException()
+        throw NotConstArgumentException()
-        function(constants.map { it!!.toDouble() }).toDouble()
+
-    } else {
+    return NumericLiteralValue.optimalNumeric(function(constElements.mapNotNull { it }), args[0].position)
-        when(iterable.type) {
-            DataType.UBYTE, DataType.UWORD, DataType.FLOAT -> throw SyntaxError("function expects an iterable type", position)
-            else -> {
-                if(iterable.heapId==null)
-                    throw FatalAstException("iterable value should be on the heap")
-                val array = heap.get(iterable.heapId).array ?: throw SyntaxError("function expects an iterable type", position)
-                function(array.map { it.toDouble() })
-            }
-        }
-    }
-    return numericLiteral(result, args[0].position)
 }
 
-private fun collectionArgOutputBoolean(args: List<IExpression>, position: Position,
+private fun builtinAbs(args: List<Expression>, position: Position, program: Program): NumericLiteralValue {
-                                       namespace:INameScope, heap: HeapValues,
+    // 1 arg, type = float or int, result type= isSameAs as argument type
-                                       function: (arg: Collection<Double>)->Boolean): LiteralValue {
-    if(args.size!=1)
-        throw SyntaxError("builtin function requires one non-scalar argument", position)
-    val iterable = args[0].constValue(namespace, heap) ?: throw NotConstArgumentException()
-
-    val result = if(iterable.arrayvalue != null) {
-        val constants = iterable.arrayvalue.map { it.constValue(namespace, heap)?.asNumericValue }
-        if(null in constants)
-            throw NotConstArgumentException()
-        function(constants.map { it!!.toDouble() })
-    } else {
-        val array = heap.get(iterable.heapId!!).array ?: throw SyntaxError("function requires array argument", position)
-        function(array.map { it.toDouble() })
-    }
-    return LiteralValue.fromBoolean(result, position)
-}
-
-private fun builtinAbs(args: List<IExpression>, position: Position, namespace:INameScope, heap: HeapValues): LiteralValue {
-    // 1 arg, type = float or int, result type= same as argument type
     if(args.size!=1)
         throw SyntaxError("abs requires one numeric argument", position)
 
-    val constval = args[0].constValue(namespace, heap) ?: throw NotConstArgumentException()
+    val constval = args[0].constValue(program) ?: throw NotConstArgumentException()
-    val number = constval.asNumericValue
+    return when (constval.type) {
-    return when (number) {
+        in IntegerDatatypes -> numericLiteral(abs(constval.number.toInt()), args[0].position)
-        is Int, is Byte, is Short -> numericLiteral(Math.abs(number.toInt()), args[0].position)
+        DataType.FLOAT -> numericLiteral(abs(constval.number.toDouble()), args[0].position)
-        is Double -> numericLiteral(Math.abs(number.toDouble()), args[0].position)
         else -> throw SyntaxError("abs requires one numeric argument", position)
     }
 }
 
-private fun builtinAvg(args: List<IExpression>, position: Position, namespace:INameScope, heap: HeapValues): LiteralValue {
+private fun builtinSizeof(args: List<Expression>, position: Position, program: Program): NumericLiteralValue {
+    // 1 arg, type = anything, result type = ubyte
     if(args.size!=1)
-        throw SyntaxError("avg requires array argument", position)
+        throw SyntaxError("sizeof requires one argument", position)
-    val iterable = args[0].constValue(namespace, heap) ?: throw NotConstArgumentException()
+    if(args[0] !is IdentifierReference)
+        throw SyntaxError("sizeof argument should be an identifier", position)
 
-    val result = if(iterable.arrayvalue!=null) {
+    val dt = args[0].inferType(program)
-        val constants = iterable.arrayvalue.map { it.constValue(namespace, heap)?.asNumericValue }
+    if(dt.isKnown) {
-        if (null in constants)
+        val target = (args[0] as IdentifierReference).targetStatement(program.namespace)
-            throw NotConstArgumentException()
+                ?: throw CannotEvaluateException("sizeof", "no target")
-        (constants.map { it!!.toDouble() }).average()
+
+        fun structSize(target: StructDecl) =
+                NumericLiteralValue(DataType.UBYTE, target.statements.map { (it as VarDecl).datatype.memorySize() }.sum(), position)
+
+        return when {
+            dt.typeOrElse(DataType.STRUCT) in ArrayDatatypes -> {
+                val length = (target as VarDecl).arraysize!!.constIndex() ?: throw CannotEvaluateException("sizeof", "unknown array size")
+                val elementDt = ArrayElementTypes.getValue(dt.typeOrElse(DataType.STRUCT))
+                numericLiteral(elementDt.memorySize() * length, position)
+            }
+            dt.istype(DataType.STRUCT) -> {
+                when (target) {
+                    is VarDecl -> structSize(target.struct!!)
+                    is StructDecl -> structSize(target)
+                    else -> throw CompilerException("weird struct type $target")
+                }
+            }
+            dt.istype(DataType.STR) -> throw SyntaxError("sizeof str is undefined, did you mean len?", position)
+            else -> NumericLiteralValue(DataType.UBYTE, dt.typeOrElse(DataType.STRUCT).memorySize(), position)
+        }
+    } else {
+        throw SyntaxError("sizeof invalid argument type", position)
     }
-    else {
-        val array = heap.get(iterable.heapId!!).array ?: throw SyntaxError("avg requires array argument", position)
-        array.average()
-    }
-    return numericLiteral(result, args[0].position)
 }
 
-private fun builtinLen(args: List<IExpression>, position: Position, namespace:INameScope, heap: HeapValues): LiteralValue {
+private fun builtinStrlen(args: List<Expression>, position: Position, program: Program): NumericLiteralValue {
-    // note: in some cases the length is > 255 and so we have to return a UWORD type instead of a byte.
+    if (args.size != 1)
+        throw SyntaxError("strlen requires one argument", position)
+    val argument=args[0]
+    if(argument is StringLiteralValue)
+        return NumericLiteralValue.optimalInteger(argument.value.length, argument.position)
+    val vardecl = (argument as IdentifierReference).targetVarDecl(program.namespace)
+    if(vardecl!=null) {
+        if(vardecl.datatype!=DataType.STR)
+            throw SyntaxError("strlen must have string argument", position)
+        if(vardecl.autogeneratedDontRemove) {
+            return NumericLiteralValue.optimalInteger((vardecl.value as StringLiteralValue).value.length, argument.position)
+        }
+    }
+    throw NotConstArgumentException()
+}
+
+private fun builtinLen(args: List<Expression>, position: Position, program: Program): NumericLiteralValue {
+    // note: in some cases the length is > 255 and then we have to return a UWORD type instead of a UBYTE.
     if(args.size!=1)
         throw SyntaxError("len requires one argument", position)
-    var argument = args[0].constValue(namespace, heap)
+
-    if(argument==null) {
+    val directMemVar = ((args[0] as? DirectMemoryRead)?.addressExpression as? IdentifierReference)?.targetVarDecl(program.namespace)
-        if(args[0] !is IdentifierReference)
+    var arraySize = directMemVar?.arraysize?.constIndex()
-            throw SyntaxError("len over weird argument ${args[0]}", position)
+    if(arraySize != null)
-        val target = (args[0] as IdentifierReference).targetStatement(namespace)
+        return NumericLiteralValue.optimalInteger(arraySize, position)
-        val argValue = (target as? VarDecl)?.value
+    if(args[0] is ArrayLiteralValue)
-        argument = argValue?.constValue(namespace, heap)
+        return NumericLiteralValue.optimalInteger((args[0] as ArrayLiteralValue).value.size, position)
-                ?: throw NotConstArgumentException()
+    if(args[0] !is IdentifierReference)
-    }
+        throw SyntaxError("len argument should be an identifier", position)
-    return when(argument.type) {
+    val target = (args[0] as IdentifierReference).targetVarDecl(program.namespace)
-        DataType.ARRAY_UB, DataType.ARRAY_B, DataType.ARRAY_UW, DataType.ARRAY_W -> {
+            ?: throw CannotEvaluateException("len", "no target vardecl")
-            val arraySize = argument.arrayvalue?.size ?: heap.get(argument.heapId!!).arraysize
+
-            if(arraySize>256)
+    return when(target.datatype) {
-                throw CompilerException("array length exceeds byte limit ${argument.position}")
+        DataType.ARRAY_UB, DataType.ARRAY_B, DataType.ARRAY_UW, DataType.ARRAY_W, DataType.ARRAY_F -> {
-            LiteralValue(DataType.UWORD, wordvalue=arraySize, position=args[0].position)
+            arraySize = target.arraysize?.constIndex()
+            if(arraySize==null)
+                throw CannotEvaluateException("len", "arraysize unknown")
+            NumericLiteralValue.optimalInteger(arraySize, args[0].position)
         }
-        DataType.ARRAY_F -> {
+        DataType.STR -> {
-            val arraySize = argument.arrayvalue?.size ?: heap.get(argument.heapId!!).arraysize
+            val refLv = target.value as StringLiteralValue
-            if(arraySize>256)
+            NumericLiteralValue.optimalInteger(refLv.value.length, args[0].position)
-                throw CompilerException("array length exceeds byte limit ${argument.position}")
-            LiteralValue(DataType.UWORD, wordvalue=arraySize, position=args[0].position)
         }
-        DataType.STR, DataType.STR_P, DataType.STR_S, DataType.STR_PS -> {
+        DataType.STRUCT -> throw SyntaxError("cannot use len on struct, did you mean sizeof?", args[0].position)
-            val str = argument.strvalue(heap)
+        in NumericDatatypes -> throw SyntaxError("cannot use len on numeric value, did you mean sizeof?", args[0].position)
-            if(str.length>255)
+        else -> throw CompilerException("weird datatype")
-                throw CompilerException("string length exceeds byte limit ${argument.position}")
-            LiteralValue(DataType.UWORD, wordvalue=str.length, position=args[0].position)
-        }
-        DataType.UBYTE, DataType.BYTE,
-        DataType.UWORD, DataType.WORD,
-        DataType.FLOAT -> throw SyntaxError("len of weird argument ${args[0]}", position)
     }
 }
 
 
-private fun builtinMkword(args: List<IExpression>, position: Position, namespace:INameScope, heap: HeapValues): LiteralValue {
+private fun builtinMkword(args: List<Expression>, position: Position, program: Program): NumericLiteralValue {
     if (args.size != 2)
-        throw SyntaxError("mkword requires lsb and msb arguments", position)
+        throw SyntaxError("mkword requires msb and lsb arguments", position)
-    val constLsb = args[0].constValue(namespace, heap) ?: throw NotConstArgumentException()
+    val constMsb = args[0].constValue(program) ?: throw NotConstArgumentException()
-    val constMsb = args[1].constValue(namespace, heap) ?: throw NotConstArgumentException()
+    val constLsb = args[1].constValue(program) ?: throw NotConstArgumentException()
-    val result = (constMsb.asIntegerValue!! shl 8) or constLsb.asIntegerValue!!
+    val result = (constMsb.number.toInt() shl 8) or constLsb.number.toInt()
-    return LiteralValue(DataType.UWORD, wordvalue = result, position = position)
+    return NumericLiteralValue(DataType.UWORD, result, position)
 }
 
-private fun builtinSin8(args: List<IExpression>, position: Position, namespace:INameScope, heap: HeapValues): LiteralValue {
+private fun builtinSin8(args: List<Expression>, position: Position, program: Program): NumericLiteralValue {
     if (args.size != 1)
         throw SyntaxError("sin8 requires one argument", position)
-    val constval = args[0].constValue(namespace, heap) ?: throw NotConstArgumentException()
+    val constval = args[0].constValue(program) ?: throw NotConstArgumentException()
-    val rad = constval.asNumericValue!!.toDouble() /256.0 * 2.0 * PI
+    val rad = constval.number.toDouble() /256.0 * 2.0 * PI
-    return LiteralValue(DataType.BYTE, bytevalue = (127.0* sin(rad)).toShort(), position = position)
+    return NumericLiteralValue(DataType.BYTE, (127.0 * sin(rad)).toInt().toShort(), position)
 }
 
-private fun builtinSin8u(args: List<IExpression>, position: Position, namespace:INameScope, heap: HeapValues): LiteralValue {
+private fun builtinSin8u(args: List<Expression>, position: Position, program: Program): NumericLiteralValue {
     if (args.size != 1)
         throw SyntaxError("sin8u requires one argument", position)
-    val constval = args[0].constValue(namespace, heap) ?: throw NotConstArgumentException()
+    val constval = args[0].constValue(program) ?: throw NotConstArgumentException()
-    val rad = constval.asNumericValue!!.toDouble() /256.0 * 2.0 * PI
+    val rad = constval.number.toDouble() /256.0 * 2.0 * PI
-    return LiteralValue(DataType.UBYTE, bytevalue = (128.0+127.5*sin(rad)).toShort(), position = position)
+    return NumericLiteralValue(DataType.UBYTE, (128.0 + 127.5 * sin(rad)).toInt().toShort(), position)
 }
 
-private fun builtinCos8(args: List<IExpression>, position: Position, namespace:INameScope, heap: HeapValues): LiteralValue {
+private fun builtinCos8(args: List<Expression>, position: Position, program: Program): NumericLiteralValue {
     if (args.size != 1)
         throw SyntaxError("cos8 requires one argument", position)
-    val constval = args[0].constValue(namespace, heap) ?: throw NotConstArgumentException()
+    val constval = args[0].constValue(program) ?: throw NotConstArgumentException()
-    val rad = constval.asNumericValue!!.toDouble() /256.0 * 2.0 * PI
+    val rad = constval.number.toDouble() /256.0 * 2.0 * PI
-    return LiteralValue(DataType.BYTE, bytevalue = (127.0* cos(rad)).toShort(), position = position)
+    return NumericLiteralValue(DataType.BYTE, (127.0 * cos(rad)).toInt().toShort(), position)
 }
 
-private fun builtinCos8u(args: List<IExpression>, position: Position, namespace:INameScope, heap: HeapValues): LiteralValue {
+private fun builtinCos8u(args: List<Expression>, position: Position, program: Program): NumericLiteralValue {
     if (args.size != 1)
         throw SyntaxError("cos8u requires one argument", position)
-    val constval = args[0].constValue(namespace, heap) ?: throw NotConstArgumentException()
+    val constval = args[0].constValue(program) ?: throw NotConstArgumentException()
-    val rad = constval.asNumericValue!!.toDouble() /256.0 * 2.0 * PI
+    val rad = constval.number.toDouble() /256.0 * 2.0 * PI
-    return LiteralValue(DataType.UBYTE, bytevalue = (128.0 + 127.5*cos(rad)).toShort(), position = position)
+    return NumericLiteralValue(DataType.UBYTE, (128.0 + 127.5 * cos(rad)).toInt().toShort(), position)
 }
 
-private fun builtinSin16(args: List<IExpression>, position: Position, namespace:INameScope, heap: HeapValues): LiteralValue {
+private fun builtinSin16(args: List<Expression>, position: Position, program: Program): NumericLiteralValue {
     if (args.size != 1)
         throw SyntaxError("sin16 requires one argument", position)
-    val constval = args[0].constValue(namespace, heap) ?: throw NotConstArgumentException()
+    val constval = args[0].constValue(program) ?: throw NotConstArgumentException()
-    val rad = constval.asNumericValue!!.toDouble() /256.0 * 2.0 * PI
+    val rad = constval.number.toDouble() /256.0 * 2.0 * PI
-    return LiteralValue(DataType.WORD, wordvalue = (32767.0* sin(rad)).toInt(), position = position)
+    return NumericLiteralValue(DataType.WORD, (32767.0 * sin(rad)).toInt(), position)
 }
 
-private fun builtinSin16u(args: List<IExpression>, position: Position, namespace:INameScope, heap: HeapValues): LiteralValue {
+private fun builtinSin16u(args: List<Expression>, position: Position, program: Program): NumericLiteralValue {
     if (args.size != 1)
         throw SyntaxError("sin16u requires one argument", position)
-    val constval = args[0].constValue(namespace, heap) ?: throw NotConstArgumentException()
+    val constval = args[0].constValue(program) ?: throw NotConstArgumentException()
-    val rad = constval.asNumericValue!!.toDouble() /256.0 * 2.0 * PI
+    val rad = constval.number.toDouble() /256.0 * 2.0 * PI
-    return LiteralValue(DataType.UWORD, wordvalue = (32768.0+32767.5*sin(rad)).toInt(), position = position)
+    return NumericLiteralValue(DataType.UWORD, (32768.0 + 32767.5 * sin(rad)).toInt(), position)
 }
 
-private fun builtinCos16(args: List<IExpression>, position: Position, namespace:INameScope, heap: HeapValues): LiteralValue {
+private fun builtinCos16(args: List<Expression>, position: Position, program: Program): NumericLiteralValue {
     if (args.size != 1)
         throw SyntaxError("cos16 requires one argument", position)
-    val constval = args[0].constValue(namespace, heap) ?: throw NotConstArgumentException()
+    val constval = args[0].constValue(program) ?: throw NotConstArgumentException()
-    val rad = constval.asNumericValue!!.toDouble() /256.0 * 2.0 * PI
+    val rad = constval.number.toDouble() /256.0 * 2.0 * PI
-    return LiteralValue(DataType.WORD, wordvalue = (32767.0* cos(rad)).toInt(), position = position)
+    return NumericLiteralValue(DataType.WORD, (32767.0 * cos(rad)).toInt(), position)
 }
 
-private fun builtinCos16u(args: List<IExpression>, position: Position, namespace:INameScope, heap: HeapValues): LiteralValue {
+private fun builtinCos16u(args: List<Expression>, position: Position, program: Program): NumericLiteralValue {
     if (args.size != 1)
         throw SyntaxError("cos16u requires one argument", position)
-    val constval = args[0].constValue(namespace, heap) ?: throw NotConstArgumentException()
+    val constval = args[0].constValue(program) ?: throw NotConstArgumentException()
-    val rad = constval.asNumericValue!!.toDouble() /256.0 * 2.0 * PI
+    val rad = constval.number.toDouble() /256.0 * 2.0 * PI
-    return LiteralValue(DataType.UWORD, wordvalue = (32768.0+32767.5* cos(rad)).toInt(), position = position)
+    return NumericLiteralValue(DataType.UWORD, (32768.0 + 32767.5 * cos(rad)).toInt(), position)
 }
 
-private fun numericLiteral(value: Number, position: Position): LiteralValue {
+private fun builtinSgn(args: List<Expression>, position: Position, program: Program): NumericLiteralValue {
+    if (args.size != 1)
+        throw SyntaxError("sgn requires one argument", position)
+    val constval = args[0].constValue(program) ?: throw NotConstArgumentException()
+    return NumericLiteralValue(DataType.BYTE, constval.number.toDouble().sign.toInt().toShort(), position)
+}
+
+private fun numericLiteral(value: Number, position: Position): NumericLiteralValue {
     val floatNum=value.toDouble()
     val tweakedValue: Number =
-            if(floatNum==Math.floor(floatNum) && (floatNum>=-32768 && floatNum<=65535))
+            if(floatNum== floor(floatNum) && (floatNum>=-32768 && floatNum<=65535))
                 floatNum.toInt()  // we have an integer disguised as a float.
             else
                 floatNum
 
     return when(tweakedValue) {
-        is Int -> LiteralValue.optimalNumeric(value.toInt(), position)
+        is Int -> NumericLiteralValue.optimalInteger(value.toInt(), position)
-        is Short -> LiteralValue.optimalNumeric(value.toInt(), position)
+        is Short -> NumericLiteralValue.optimalInteger(value.toInt(), position)
-        is Byte -> LiteralValue(DataType.UBYTE, bytevalue = value.toShort(), position = position)
+        is Byte -> NumericLiteralValue(DataType.UBYTE, value.toShort(), position)
-        is Double -> LiteralValue(DataType.FLOAT, floatvalue = value.toDouble(), position = position)
+        is Double -> NumericLiteralValue(DataType.FLOAT, value.toDouble(), position)
-        is Float -> LiteralValue(DataType.FLOAT, floatvalue = value.toDouble(), position = position)
+        is Float -> NumericLiteralValue(DataType.FLOAT, value.toDouble(), position)
         else -> throw FatalAstException("invalid number type ${value::class}")
     }
 }

compiler/src/prog8/optimizer/CallGraph.kt

@@ -0,0 +1,211 @@
+package prog8.optimizer
+
+import prog8.ast.INameScope
+import prog8.ast.Module
+import prog8.ast.Node
+import prog8.ast.Program
+import prog8.ast.base.DataType
+import prog8.ast.base.ParentSentinel
+import prog8.ast.expressions.FunctionCall
+import prog8.ast.expressions.IdentifierReference
+import prog8.ast.processing.IAstVisitor
+import prog8.ast.statements.*
+import prog8.compiler.loadAsmIncludeFile
+
+private val alwaysKeepSubroutines = setOf(
+        Pair("main", "start"),
+        Pair("irq", "irq")
+)
+
+private val asmJumpRx = Regex("""[\-+a-zA-Z0-9_ \t]+(jmp|jsr)[ \t]+(\S+).*""", RegexOption.IGNORE_CASE)
+private val asmRefRx = Regex("""[\-+a-zA-Z0-9_ \t]+(...)[ \t]+(\S+).*""", RegexOption.IGNORE_CASE)
+
+
+class CallGraph(private val program: Program) : IAstVisitor {
+
+    val imports = mutableMapOf<Module, List<Module>>().withDefault { mutableListOf() }
+    val importedBy = mutableMapOf<Module, List<Module>>().withDefault { mutableListOf() }
+    val calls = mutableMapOf<INameScope, List<Subroutine>>().withDefault { mutableListOf() }
+    val calledBy = mutableMapOf<Subroutine, List<Node>>().withDefault { mutableListOf() }
+
+    // TODO  add dataflow graph: what statements use what variables - can be used to eliminate unused vars
+    val usedSymbols = mutableSetOf<Statement>()
+
+    init {
+        visit(program)
+    }
+
+    fun forAllSubroutines(scope: INameScope, sub: (s: Subroutine) -> Unit) {
+        fun findSubs(scope: INameScope) {
+            scope.statements.forEach {
+                if (it is Subroutine)
+                    sub(it)
+                if (it is INameScope)
+                    findSubs(it)
+            }
+        }
+        findSubs(scope)
+    }
+
+    override fun visit(program: Program) {
+        super.visit(program)
+
+        program.modules.forEach {
+            it.importedBy.clear()
+            it.imports.clear()
+
+            it.importedBy.addAll(importedBy.getValue(it))
+            it.imports.addAll(imports.getValue(it))
+        }
+
+        val rootmodule = program.modules.first()
+        rootmodule.importedBy.add(rootmodule)       // don't discard root module
+    }
+
+    override fun visit(block: Block) {
+        if (block.definingModule().isLibraryModule) {
+            // make sure the block is not removed
+            addNodeAndParentScopes(block)
+        }
+
+        super.visit(block)
+    }
+
+    override fun visit(directive: Directive) {
+        val thisModule = directive.definingModule()
+        if (directive.directive == "%import") {
+            val importedModule: Module = program.modules.single { it.name == directive.args[0].name }
+            imports[thisModule] = imports.getValue(thisModule).plus(importedModule)
+            importedBy[importedModule] = importedBy.getValue(importedModule).plus(thisModule)
+        } else if (directive.directive == "%asminclude") {
+            val asm = loadAsmIncludeFile(directive.args[0].str!!, thisModule.source)
+            val scope = directive.definingScope()
+            scanAssemblyCode(asm, directive, scope)
+        }
+
+        super.visit(directive)
+    }
+
+    override fun visit(identifier: IdentifierReference) {
+        // track symbol usage
+        val target = identifier.targetStatement(this.program.namespace)
+        if (target != null) {
+            addNodeAndParentScopes(target)
+        }
+        super.visit(identifier)
+    }
+
+    private fun addNodeAndParentScopes(stmt: Statement) {
+        usedSymbols.add(stmt)
+        var node: Node = stmt
+        do {
+            if (node is INameScope && node is Statement) {
+                usedSymbols.add(node)
+            }
+            node = node.parent
+        } while (node !is Module && node !is ParentSentinel)
+    }
+
+    override fun visit(subroutine: Subroutine) {
+        if (Pair(subroutine.definingScope().name, subroutine.name) in alwaysKeepSubroutines
+                || subroutine.definingModule().isLibraryModule) {
+            // make sure the entrypoint is mentioned in the used symbols
+            addNodeAndParentScopes(subroutine)
+        }
+        super.visit(subroutine)
+    }
+
+    override fun visit(decl: VarDecl) {
+        if (decl.autogeneratedDontRemove || decl.definingModule().isLibraryModule) {
+            // make sure autogenerated vardecls are in the used symbols and are never removed as 'unused'
+            addNodeAndParentScopes(decl)
+        }
+
+        if (decl.datatype == DataType.STRUCT)
+            addNodeAndParentScopes(decl)
+
+        super.visit(decl)
+    }
+
+    override fun visit(functionCall: FunctionCall) {
+        val otherSub = functionCall.target.targetSubroutine(program.namespace)
+        if (otherSub != null) {
+            functionCall.definingSubroutine()?.let { thisSub ->
+                calls[thisSub] = calls.getValue(thisSub).plus(otherSub)
+                calledBy[otherSub] = calledBy.getValue(otherSub).plus(functionCall)
+            }
+        }
+        super.visit(functionCall)
+    }
+
+    override fun visit(functionCallStatement: FunctionCallStatement) {
+        val otherSub = functionCallStatement.target.targetSubroutine(program.namespace)
+        if (otherSub != null) {
+            functionCallStatement.definingSubroutine()?.let { thisSub ->
+                calls[thisSub] = calls.getValue(thisSub).plus(otherSub)
+                calledBy[otherSub] = calledBy.getValue(otherSub).plus(functionCallStatement)
+            }
+        }
+        super.visit(functionCallStatement)
+    }
+
+    override fun visit(jump: Jump) {
+        val otherSub = jump.identifier?.targetSubroutine(program.namespace)
+        if (otherSub != null) {
+            jump.definingSubroutine()?.let { thisSub ->
+                calls[thisSub] = calls.getValue(thisSub).plus(otherSub)
+                calledBy[otherSub] = calledBy.getValue(otherSub).plus(jump)
+            }
+        }
+        super.visit(jump)
+    }
+
+    override fun visit(structDecl: StructDecl) {
+        usedSymbols.add(structDecl)
+        usedSymbols.addAll(structDecl.statements)
+    }
+
+    override fun visit(inlineAssembly: InlineAssembly) {
+        // parse inline asm for subroutine calls (jmp, jsr)
+        val scope = inlineAssembly.definingScope()
+        scanAssemblyCode(inlineAssembly.assembly, inlineAssembly, scope)
+        super.visit(inlineAssembly)
+    }
+
+    private fun scanAssemblyCode(asm: String, context: Statement, scope: INameScope) {
+        asm.lines().forEach { line ->
+            val matches = asmJumpRx.matchEntire(line)
+            if (matches != null) {
+                val jumptarget = matches.groups[2]?.value
+                if (jumptarget != null && (jumptarget[0].isLetter() || jumptarget[0] == '_')) {
+                    val node = program.namespace.lookup(jumptarget.split('.'), context)
+                    if (node is Subroutine) {
+                        calls[scope] = calls.getValue(scope).plus(node)
+                        calledBy[node] = calledBy.getValue(node).plus(context)
+                    } else if (jumptarget.contains('.')) {
+                        // maybe only the first part already refers to a subroutine
+                        val node2 = program.namespace.lookup(listOf(jumptarget.substringBefore('.')), context)
+                        if (node2 is Subroutine) {
+                            calls[scope] = calls.getValue(scope).plus(node2)
+                            calledBy[node2] = calledBy.getValue(node2).plus(context)
+                        }
+                    }
+                }
+            } else {
+                val matches2 = asmRefRx.matchEntire(line)
+                if (matches2 != null) {
+                    val target = matches2.groups[2]?.value
+                    if (target != null && (target[0].isLetter() || target[0] == '_')) {
+                        if (target.contains('.')) {
+                            val node = program.namespace.lookup(listOf(target.substringBefore('.')), context)
+                            if (node is Subroutine) {
+                                calls[scope] = calls.getValue(scope).plus(node)
+                                calledBy[node] = calledBy.getValue(node).plus(context)
+                            }
+                        }
+                    }
+                }
+            }
+        }
+    }
+}