vm/math.p8: complete the sin and cos routines

Fixed by reintroducing splitting of comparison expression in if statements by using a temporary variable and/or register to precompute left/right values.

.gitignore

@@ -26,6 +26,9 @@ parser.out
 parsetab.py
 .pytest_cache/
 .attach_pid*
+compiler/lib/
 
 .gradle
 /prog8compiler.jar
+sd*.img
+*.d64

.idea/codeInsightSettings.xml

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="JavaProjectCodeInsightSettings">
+    <excluded-names>
+      <name>kotlin.Result</name>
+    </excluded-names>
+  </component>
+</project>

.idea/codeStyles/Project.xml

@@ -0,0 +1,10 @@
+<component name="ProjectCodeStyleConfiguration">
+  <code_scheme name="Project" version="173">
+    <JetCodeStyleSettings>
+      <option name="CODE_STYLE_DEFAULTS" value="KOTLIN_OFFICIAL" />
+    </JetCodeStyleSettings>
+    <codeStyleSettings language="kotlin">
+      <option name="CODE_STYLE_DEFAULTS" value="KOTLIN_OFFICIAL" />
+    </codeStyleSettings>
+  </code_scheme>
+</component>

.idea/codeStyles/codeStyleConfig.xml

@@ -0,0 +1,5 @@
+<component name="ProjectCodeStyleConfiguration">
+  <state>
+    <option name="USE_PER_PROJECT_SETTINGS" value="true" />
+  </state>
+</component>

.idea/compiler.xml

@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="CompilerConfiguration">
+    <option name="BUILD_PROCESS_HEAP_SIZE" value="3000" />
+    <bytecodeTargetLevel target="11" />
+  </component>
+</project>

.idea/inspectionProfiles/Project_Default.xml

@@ -3,14 +3,12 @@
     <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="Groovy" />
-        <language isEnabled="false" name="ActionScript" />
       </Languages>
     </inspection_tool>
+    <inspection_tool class="IncompleteDestructuring" enabled="true" level="WARNING" enabled_by_default="true" />
+    <inspection_tool class="PyInterpreterInspection" enabled="false" level="WARNING" enabled_by_default="false" />
     <inspection_tool class="SpellCheckingInspection" enabled="true" level="TYPO" enabled_by_default="true">
       <option name="processCode" value="false" />
       <option name="processLiterals" value="true" />

.idea/kotlinc.xml

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

.idea/libraries/antlr_4_7_2_complete.xml

@@ -1,9 +0,0 @@
-<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

@@ -1,9 +0,0 @@
-<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_antlr4.xml

@@ -0,0 +1,19 @@
+<component name="libraryTable">
+  <library name="antlr.antlr4" type="repository">
+    <properties maven-id="org.antlr:antlr4:4.10.1">
+      <exclude>
+        <dependency maven-id="com.ibm.icu:icu4j" />
+      </exclude>
+    </properties>
+    <CLASSES>
+      <root url="jar://$MAVEN_REPOSITORY$/org/antlr/antlr4/4.10.1/antlr4-4.10.1.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/antlr/antlr4-runtime/4.10.1/antlr4-runtime-4.10.1.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/antlr/antlr-runtime/3.5.3/antlr-runtime-3.5.3.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/antlr/ST4/4.3.3/ST4-4.3.3.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/abego/treelayout/org.abego.treelayout.core/1.0.3/org.abego.treelayout.core-1.0.3.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/glassfish/javax.json/1.0.4/javax.json-1.0.4.jar!/" />
+    </CLASSES>
+    <JAVADOC />
+    <SOURCES />
+  </library>
+</component>

.idea/libraries/antlr_runtime_4_7_2.xml

@@ -1,9 +0,0 @@
-<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

@@ -1,9 +0,0 @@
-<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/github_hypfvieh_dbus_java.xml

@@ -0,0 +1,25 @@
+<component name="libraryTable">
+  <library name="github.hypfvieh.dbus.java" type="repository">
+    <properties maven-id="com.github.hypfvieh:dbus-java:3.3.1" />
+    <CLASSES>
+      <root url="jar://$MAVEN_REPOSITORY$/com/github/hypfvieh/dbus-java/3.3.1/dbus-java-3.3.1.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/com/github/jnr/jnr-unixsocket/0.38.6/jnr-unixsocket-0.38.6.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/com/github/jnr/jnr-ffi/2.2.2/jnr-ffi-2.2.2.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/com/github/jnr/jffi/1.3.1/jffi-1.3.1.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/com/github/jnr/jffi/1.3.1/jffi-1.3.1-native.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/ow2/asm/asm/9.1/asm-9.1.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/ow2/asm/asm-commons/9.1/asm-commons-9.1.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/ow2/asm/asm-analysis/9.1/asm-analysis-9.1.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/ow2/asm/asm-tree/9.1/asm-tree-9.1.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/ow2/asm/asm-util/9.1/asm-util-9.1.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/com/github/jnr/jnr-a64asm/1.0.0/jnr-a64asm-1.0.0.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/com/github/jnr/jnr-x86asm/1.0.2/jnr-x86asm-1.0.2.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/com/github/jnr/jnr-constants/0.10.1/jnr-constants-0.10.1.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/com/github/jnr/jnr-enxio/0.32.4/jnr-enxio-0.32.4.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/com/github/jnr/jnr-posix/3.1.5/jnr-posix-3.1.5.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/slf4j/slf4j-api/1.7.30/slf4j-api-1.7.30.jar!/" />
+    </CLASSES>
+    <JAVADOC />
+    <SOURCES />
+  </library>
+</component>

.idea/libraries/glassfish_javax_json.xml

@@ -0,0 +1,10 @@
+<component name="libraryTable">
+  <library name="glassfish.javax.json" type="repository">
+    <properties include-transitive-deps="false" maven-id="org.glassfish:javax.json:1.1.4" />
+    <CLASSES>
+      <root url="jar://$MAVEN_REPOSITORY$/org/glassfish/javax.json/1.1.4/javax.json-1.1.4.jar!/" />
+    </CLASSES>
+    <JAVADOC />
+    <SOURCES />
+  </library>
+</component>

.idea/libraries/io_kotest_assertions_core_jvm.xml

@@ -0,0 +1,23 @@
+<component name="libraryTable">
+  <library name="io.kotest.assertions.core.jvm" type="repository">
+    <properties maven-id="io.kotest:kotest-assertions-core-jvm:5.3.2" />
+    <CLASSES>
+      <root url="jar://$MAVEN_REPOSITORY$/io/kotest/kotest-assertions-core-jvm/5.3.2/kotest-assertions-core-jvm-5.3.2.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/kotlin/kotlin-stdlib-jdk8/1.6.21/kotlin-stdlib-jdk8-1.6.21.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/kotlin/kotlin-stdlib/1.6.21/kotlin-stdlib-1.6.21.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/annotations/13.0/annotations-13.0.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/kotlin/kotlin-stdlib-jdk7/1.6.21/kotlin-stdlib-jdk7-1.6.21.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/io/kotest/kotest-assertions-shared-jvm/5.3.2/kotest-assertions-shared-jvm-5.3.2.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/io/github/java-diff-utils/java-diff-utils/4.11/java-diff-utils-4.11.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/opentest4j/opentest4j/1.2.0/opentest4j-1.2.0.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/kotlinx/kotlinx-coroutines-jdk8/1.6.1/kotlinx-coroutines-jdk8-1.6.1.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/kotlin/kotlin-reflect/1.6.21/kotlin-reflect-1.6.21.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/kotlinx/kotlinx-coroutines-core-jvm/1.6.1/kotlinx-coroutines-core-jvm-1.6.1.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/kotlin/kotlin-stdlib-common/1.6.0/kotlin-stdlib-common-1.6.0.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/io/kotest/kotest-common-jvm/5.3.2/kotest-common-jvm-5.3.2.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/io/kotest/kotest-assertions-api-jvm/5.3.2/kotest-assertions-api-jvm-5.3.2.jar!/" />
+    </CLASSES>
+    <JAVADOC />
+    <SOURCES />
+  </library>
+</component>

.idea/libraries/io_kotest_property_jvm.xml

@@ -0,0 +1,24 @@
+<component name="libraryTable">
+  <library name="io.kotest.property.jvm" type="repository">
+    <properties maven-id="io.kotest:kotest-property-jvm:5.3.2" />
+    <CLASSES>
+      <root url="jar://$MAVEN_REPOSITORY$/io/kotest/kotest-property-jvm/5.3.2/kotest-property-jvm-5.3.2.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/com/github/curious-odd-man/rgxgen/1.3/rgxgen-1.3.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/kotlin/kotlin-stdlib-jdk8/1.6.21/kotlin-stdlib-jdk8-1.6.21.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/kotlin/kotlin-stdlib/1.6.21/kotlin-stdlib-1.6.21.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/annotations/13.0/annotations-13.0.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/kotlin/kotlin-stdlib-jdk7/1.6.21/kotlin-stdlib-jdk7-1.6.21.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/io/kotest/kotest-common-jvm/5.3.2/kotest-common-jvm-5.3.2.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/io/kotest/kotest-assertions-shared-jvm/5.3.2/kotest-assertions-shared-jvm-5.3.2.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/io/kotest/kotest-assertions-api-jvm/5.3.2/kotest-assertions-api-jvm-5.3.2.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/kotlinx/kotlinx-coroutines-jdk8/1.6.1/kotlinx-coroutines-jdk8-1.6.1.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/opentest4j/opentest4j/1.2.0/opentest4j-1.2.0.jar!/" />
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+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/kotlinx/kotlinx-coroutines-core-jvm/1.6.1/kotlinx-coroutines-core-jvm-1.6.1.jar!/" />
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+    <SOURCES />
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+</component>

.idea/libraries/io_kotest_runner_junit5_jvm.xml

@@ -0,0 +1,53 @@
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+  <library name="io.kotest.runner.junit5.jvm" type="repository">
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+    <CLASSES>
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+      <root url="jar://$MAVEN_REPOSITORY$/io/kotest/kotest-framework-api-jvm/5.3.2/kotest-framework-api-jvm-5.3.2.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/io/kotest/kotest-assertions-shared-jvm/5.3.2/kotest-assertions-shared-jvm-5.3.2.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/io/github/java-diff-utils/java-diff-utils/4.11/java-diff-utils-4.11.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/kotlinx/kotlinx-coroutines-test-jvm/1.6.1/kotlinx-coroutines-test-jvm-1.6.1.jar!/" />
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.idea/libraries/jetbrains_kotlinx_cli_jvm.xml

@@ -0,0 +1,10 @@
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.idea/libraries/kotlinx_cli_jvm_0_1_0_dev_5.xml

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-      <root url="jar://$PROJECT_DIR$/compiler/lib/kotlinx-cli-jvm-0.1.0-dev-5.jar!/" />
-    </CLASSES>
-    <JAVADOC />
-    <SOURCES />
-  </library>
-</component>

.idea/libraries/michael_bull_kotlin_result_jvm.xml

@@ -0,0 +1,15 @@
+<component name="libraryTable">
+  <library name="michael.bull.kotlin.result.jvm" type="repository">
+    <properties maven-id="com.michael-bull.kotlin-result:kotlin-result-jvm:1.1.16" />
+    <CLASSES>
+      <root url="jar://$MAVEN_REPOSITORY$/com/michael-bull/kotlin-result/kotlin-result-jvm/1.1.16/kotlin-result-jvm-1.1.16.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/kotlin/kotlin-stdlib-common/1.6.20/kotlin-stdlib-common-1.6.20.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/kotlin/kotlin-stdlib-jdk8/1.6.20/kotlin-stdlib-jdk8-1.6.20.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/kotlin/kotlin-stdlib/1.6.20/kotlin-stdlib-1.6.20.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/annotations/13.0/annotations-13.0.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/kotlin/kotlin-stdlib-jdk7/1.6.20/kotlin-stdlib-jdk7-1.6.20.jar!/" />
+    </CLASSES>
+    <JAVADOC />
+    <SOURCES />
+  </library>
+</component>

.idea/libraries/slf4j_simple.xml

@@ -0,0 +1,11 @@
+<component name="libraryTable">
+  <library name="slf4j.simple" type="repository">
+    <properties maven-id="org.slf4j:slf4j-simple:1.7.36" />
+    <CLASSES>
+      <root url="jar://$MAVEN_REPOSITORY$/org/slf4j/slf4j-simple/1.7.36/slf4j-simple-1.7.36.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/slf4j/slf4j-api/1.7.36/slf4j-api-1.7.36.jar!/" />
+    </CLASSES>
+    <JAVADOC />
+    <SOURCES />
+  </library>
+</component>

.idea/libraries/takes.xml

@@ -0,0 +1,17 @@
+<component name="libraryTable">
+  <library name="takes" type="repository">
+    <properties maven-id="org.takes:takes:1.20" />
+    <CLASSES>
+      <root url="jar://$MAVEN_REPOSITORY$/org/takes/takes/1.20/takes-1.20.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/cactoos/cactoos/0.50/cactoos-0.50.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/javax/xml/bind/jaxb-api/2.3.0/jaxb-api-2.3.0.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/slf4j/slf4j-api/1.7.25/slf4j-api-1.7.25.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/apache/commons/commons-text/1.4/commons-text-1.4.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/apache/commons/commons-lang3/3.7/commons-lang3-3.7.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/com/sun/xml/bind/jaxb-core/2.3.0/jaxb-core-2.3.0.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/com/sun/xml/bind/jaxb-impl/2.3.0/jaxb-impl-2.3.0.jar!/" />
+    </CLASSES>
+    <JAVADOC />
+    <SOURCES />
+  </library>
+</component>

.idea/libraries/unittest_libs.xml

@@ -1,10 +0,0 @@
-<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/misc.xml

@@ -4,7 +4,7 @@
     <option name="perGrammarGenerationSettings">
       <list>
         <PerGrammarGenerationSettings>
-          <option name="fileName" value="$PROJECT_DIR$/parser/antlr/prog8.g4" />
+          <option name="fileName" value="$PROJECT_DIR$/parser/antlr/Prog8ANTLR.g4" />
           <option name="autoGen" value="true" />
           <option name="outputDir" value="$PROJECT_DIR$/parser/src/prog8/parser" />
           <option name="libDir" value="" />
@@ -16,7 +16,10 @@
       </list>
     </option>
   </component>
-  <component name="ProjectRootManager" version="2" languageLevel="JDK_1_8" default="false" project-jdk-name="Kotlin SDK" project-jdk-type="KotlinSDK">
+  <component name="FrameworkDetectionExcludesConfiguration">
+    <type id="Python" />
+  </component>
+  <component name="ProjectRootManager" version="2" languageLevel="JDK_11" default="true" project-jdk-name="11" project-jdk-type="JavaSDK">
     <output url="file://$PROJECT_DIR$/out" />
   </component>
 </project>

.idea/modules.xml

@@ -2,10 +2,21 @@
 <project version="4">
   <component name="ProjectModuleManager">
     <modules>
+      <module fileurl="file://$PROJECT_DIR$/codeCore/codeCore.iml" filepath="$PROJECT_DIR$/codeCore/codeCore.iml" />
+      <module fileurl="file://$PROJECT_DIR$/codeGenCpu6502/codeGenCpu6502.iml" filepath="$PROJECT_DIR$/codeGenCpu6502/codeGenCpu6502.iml" />
+      <module fileurl="file://$PROJECT_DIR$/codeGenExperimental/codeGenExperimental.iml" filepath="$PROJECT_DIR$/codeGenExperimental/codeGenExperimental.iml" />
+      <module fileurl="file://$PROJECT_DIR$/codeGenIntermediate/codeGenIntermediate.iml" filepath="$PROJECT_DIR$/codeGenIntermediate/codeGenIntermediate.iml" />
+      <module fileurl="file://$PROJECT_DIR$/codeGenVirtual/codeGenVirtual.iml" filepath="$PROJECT_DIR$/codeGenVirtual/codeGenVirtual.iml" />
+      <module fileurl="file://$PROJECT_DIR$/codeOptimizers/codeOptimizers.iml" filepath="$PROJECT_DIR$/codeOptimizers/codeOptimizers.iml" />
       <module fileurl="file://$PROJECT_DIR$/compiler/compiler.iml" filepath="$PROJECT_DIR$/compiler/compiler.iml" />
+      <module fileurl="file://$PROJECT_DIR$/compilerAst/compilerAst.iml" filepath="$PROJECT_DIR$/compilerAst/compilerAst.iml" />
+      <module fileurl="file://$PROJECT_DIR$/dbusCompilerService/dbusCompilerService.iml" filepath="$PROJECT_DIR$/dbusCompilerService/dbusCompilerService.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://$PROJECT_DIR$/httpCompilerService/httpCompilerService.iml" filepath="$PROJECT_DIR$/httpCompilerService/httpCompilerService.iml" />
+      <module fileurl="file://$PROJECT_DIR$/intermediate/intermediate.iml" filepath="$PROJECT_DIR$/intermediate/intermediate.iml" />
       <module fileurl="file://$PROJECT_DIR$/parser/parser.iml" filepath="$PROJECT_DIR$/parser/parser.iml" />
+      <module fileurl="file://$PROJECT_DIR$/virtualmachine/virtualmachine.iml" filepath="$PROJECT_DIR$/virtualmachine/virtualmachine.iml" />
     </modules>
   </component>
 </project>

.readthedocs.yaml

@@ -0,0 +1,29 @@
+# .readthedocs.yaml
+# Read the Docs configuration file
+# See https://docs.readthedocs.io/en/stable/config-file/v2.html for details
+
+# Required
+version: 2
+
+# Set the version of Python and other tools you might need
+build:
+  os: ubuntu-20.04
+  tools:
+    python: "3.9"
+    # You can also specify other tool versions:
+    # nodejs: "16"
+    # rust: "1.55"
+    # golang: "1.17"
+
+# Build documentation in the docs/ directory with Sphinx
+sphinx:
+  configuration: docs/source/conf.py
+
+# If using Sphinx, optionally build your docs in additional formats such as PDF
+formats:
+  - pdf
+
+# Optionally declare the Python requirements required to build your docs
+python:
+  install:
+    - requirements: docs/requirements.txt

.travis.yml

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

CompilerDevelopment.md

@@ -0,0 +1,35 @@
+#### Just a few remarks upfront:
+* There is the (gradle/IDEA) module `parser`: that's the parser generated by ANTLR4, in Java. The only file to be edited here is the grammar, `prog8.g4`.
+* Then we have the module `compilerAst` - in Kotlin - which uses `parser` and adds AST nodes. Here we put our additions to the generated thing, *including any tests of the parsing stage*.
+  - the name is a bit misleading, as this module isn't (or, resp. shouldn't be; see below) about *compiling*, only the parsing stage
+  - also, the tree that comes out isn't much of an *abstraction*, but rather still more or less a parse tree (this might very well change).
+  - **However, let's not *yet* rename the module.** We'll find a good name during refactoring.
+
+#### Problems with `compilerAst`:
+* `ModuleImporter.kt`, doing (Prog8-) module resolution. That's not the parser's job.
+* `ParsingFailedError` (in `ModuleParsing.kt`): this exception (it is actually *not* a `java.lang.Error`...) is thrown in a number of places, where other exceptions would make more sense. For example: not finding a file should just yield a `NoSuchFileException`, not this one. The other problem with it is that it does not provide any additional information about the source of parsing error, in particular a `Position`.
+* During parsing, character literals are turned into UBYTEs (since there is no basic type e.g. CHAR). That's bad because it depends on a specific character encoding (`IStringEncoding` in `compilerAst/src/prog8/ast/AstToplevel.kt`) of/for some target platform. Note that *strings* are indeed encoded later, in the `compiler` module.
+* The same argument applies to `IMemSizer`, and - not entirely sure about that - `IBuiltinFunctions`.
+
+#### Steps to take, in conceptual (!) order:
+
+(note: all these steps have been implemented, rejected or otherwise solved now.)
+
+1. introduce an abstraction `SourceCode` that encapsulates the origin and actual loading of Prog8 source code
+   - from the local file system (use case: user programs)
+   - from resources (prog8lib)
+   - from plain strings (for testing)
+2. add subclass `ParseError : ParsingFailedError` which adds information about the *source of parsing error* (`SourceCode` and `Position`). We cannot just replace `ParsingFailedError`  right away because it is so widely used (even in the `compiler` module). Therefore we'll just subclass for the time being, add more and more tests requiring the new one to be thrown (or, resp., NOT to be thrown), and gradually transition.
+3. introduce a minimal interface to the outside, input: `SourceCode`, output: a tree with a `Module` node as the root
+   - this will be the Kotlin singleton `Prog8Parser` with the main method `parseModule`
+   - plus, optionally, method's for registering/unregistering a listener with the parser
+   - the *only* exception ever thrown / reported to listeners (TBD) will be `ParseError`
+   - anything related to the lexer, error strategies, character/token streams is hidden from the outside
+   - to make a clear distinction between the *generated* parser (and lexer) vs. `Prog8Parser`, and to discourage directly using the generated stuff, we'll rename the existing `prog8Parser`/`prog8Lexer` to `Prog8ANTLRParser` and `Prog8ANTLRLexer` and move them to package `prog8.parser.generated`
+4. introduce AST node `CharLiteral` and keep them until after identifier resolution and type checking; insert there an AST transformation step that turns them in UBYTE constants (literals)
+5. remove uses of `IStringEncoding` from module `compilerAst` - none should be necessary anymore
+6. move `IStringEncoding` to module `compiler`
+7. same with `ModuleImporter`, then rewrite that (addressing #46)
+8. refactor AST nodes and grammar: less generated parse tree nodes (`XyzContext`), less intermediary stuff (private classes in `Antrl2Kotlin.kt`), more compact code. Also: nicer names such as simply `StringLiteral` instead of `StringLiteralValue`
+9. re-think `IStringEncoding` to address #38
+

LICENSE

@@ -1,3 +1,13 @@
+
+This sofware license is for Prog8 the compiler + associated library files.
+
+Exception: All output files generated by the compiler (intermediary files
+and compiled binary programs) are excluded from this; you can do with those
+whatever you want.
+
+
+
+
                     GNU GENERAL PUBLIC LICENSE
                        Version 3, 29 June 2007
 

README.md

@@ -1,5 +1,3 @@
-[![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
@@ -7,9 +5,6 @@ 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 6502/6510/65c02 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).
@@ -19,38 +14,52 @@ Documentation
 Full documentation (syntax reference, how to use the language and the compiler, etc.) can be found at:
 https://prog8.readthedocs.io/
 
+Software license
+----------------
+GNU GPL 3.0 (see file LICENSE), with exception for generated code:
 
-What use Prog8 provide?
+- The compiler and its libraries are free to use according to the terms of the GNU GPL 3.0
------------------------
+- *exception:* the resulting files (intermediate source codes and resulting binary program) created by the compiler
+  are excluded from the GPL and are free to use in whatever way desired, commercially or not.
+
+
+What does Prog8 provide?
+------------------------
 
 - reduction of source code length over raw assembly
+- fast execution speed due to compilation to native assembly code. It's possible to write certain raster interrupt 'demoscene' effects purely in Prog8.
 - modularity, symbol scoping, subroutines
 - various data types other than just bytes (16-bit words, floats, strings)
-- automatic variable allocations, automatic string and array variables and string sharing
+- floating point math is supported if the target system provides floating point library routines (C64 and Cx16 both do)
-- subroutines with an input- and output parameter signature
+- strings can contain escaped characters but also many symbols directly if they have a petscii equivalent, such as "♠♥♣♦π▚●○╳". Characters like ^, _, \, {, } and | are also accepted and converted to the closest petscii equivalents.
-- constant folding in expressions
+- automatic static variable allocations, automatic string and array variables and string sharing
+- subroutines with input parameters and result values
+- high-level program optimizations
+- small program boilerplate/compilersupport overhead
+- programs can be run multiple times without reloading because of automatic variable (re)initializations.
 - conditional branches
-- 'when' statement to provide a concise jump table alternative to if/elseif chains
+- ``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
+- ``in`` expression for concise and efficient multi-value/containment check 
-- floating point operations  (requires the C64 Basic ROM routines for this)
+- many built-in functions such as ``sin``, ``cos``, ``rnd``, ``abs``, ``min``, ``max``, ``sqrt``, ``msb``, ``rol``, ``ror``, ``swap``, ``sort`` and ``reverse``
-- abstracting away low level aspects such as ZeroPage handling, program startup, explicit memory addresses
+- various powerful built-in libraries to do I/O, number conversions, graphics and more  
-- various code optimizations (code structure, logical and numerical expressions, unused code removal...)
+- convenience abstractions for low level aspects such as ZeroPage handling, program startup, explicit memory addresses
 - 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``
+- supports the sixteen 'virtual' 16-bit registers R0 - R15 from the Commander X16, and provides them also on the C64.
+- encode strings and characters into petscii or screencodes as desired (C64/Cx16)
 
 *Rapid edit-compile-run-debug cycle:*
 
-- use a modern PC to do the work on
+- use a modern PC to do the work on, use nice editors and enjoy quick compilation times
-- 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
 
-*Two supported compiler targets* (contributions to improve these or to add support for other machines are welcome!):
+*Multiple supported compiler targets* (contributions to improve these or to add support for other machines are welcome!):
 
-- "c64": Commodore-64  (6510 CPU = almost a 6502)  premium support.
+- "c64": Commodore-64  (6502 like CPU)
-- "cx16": [CommanderX16](https://www.commanderx16.com)  (65c02 CPU)  experimental support.
+- "c128": Commodore-128  (6502 like CPU - the Z80 cpu mode is not supported)
-- If you only use standard kernel and prog8 library routines, it is possible to compile the *exact same program* for both machines (just change the compiler target flag)!
+- "cx16": [CommanderX16](https://www.commanderx16.com)  (65c02 CPU)
+- If you only use standard kernal and prog8 library routines, it is possible to compile the *exact same program* for different machines (just change the compiler target flag)
 
 
 
@@ -61,7 +70,7 @@ Additional required tools
 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 a prepackaged version of the compiler.
+A **Java runtime (jre or jdk), version 11 or newer**  is required to run a prepackaged version of the compiler.
 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).
 
@@ -84,9 +93,7 @@ This code calculates prime numbers using the Sieve of Eratosthenes algorithm::
         ubyte candidate_prime = 2       ; is increased in the loop
     
         sub start() {
-            ; clear the sieve, to reset starting situation on subsequent runs
+            sys.memset(sieve, 256, false)   ; clear the sieve
-            memset(sieve, 256, false)   
-            ; calculate primes
             txt.print("prime numbers up to 255:\n\n")
             ubyte amount=0
             repeat {
@@ -97,17 +104,17 @@ This code calculates prime numbers using the Sieve of Eratosthenes algorithm::
                 txt.print(", ")
                 amount++
             }
-            txt.chrout('\n')
+            txt.nl()
             txt.print("number of primes (expected 54): ")
             txt.print_ub(amount)
-            txt.chrout('\n')
+            txt.nl()
         }
     
         sub find_next_prime() -> ubyte {
             while sieve[candidate_prime] {
                 candidate_prime++
                 if candidate_prime==0
-                    return 0        ; we wrapped; no more primes available in the sieve
+                    return 0        ; we wrapped; no more primes
             }
     
             ; found next one, mark the multiples and return it.
@@ -124,6 +131,7 @@ This code calculates prime numbers using the Sieve of Eratosthenes algorithm::
 
 
 
+
 when compiled an ran on a C-64 you'll get:
 
 ![c64 screen](docs/source/_static/primes_example.png)
@@ -140,7 +148,8 @@ If you want to play a video game, a fully working Tetris clone is included in th
 
 ![tehtriz_screen](docs/source/_static/tehtriz.png)
 
-The CommanderX16 compiler target is quite capable already too, here's a well known space ship 
+There are a couple of examples specially made for the CommanderX16 compiler target.
-animated in 3D with hidden line removal, in the CommanderX16 emulator:
+For instance here's a well known space ship animated in 3D with hidden line removal,
+in the CommanderX16 emulator:
 
 ![cobra3d](docs/source/_static/cobra3d.png)

build.gradle

@@ -0,0 +1,10 @@
+plugins {
+    id "org.jetbrains.kotlin.jvm" version "$kotlinVersion" apply false
+}
+
+allprojects {
+    repositories {
+        mavenLocal()
+        mavenCentral()
+    }
+}

codeCore/build.gradle

@@ -0,0 +1,43 @@
+
+plugins {
+    id 'java'
+    id 'application'
+    id "org.jetbrains.kotlin.jvm"
+}
+
+java {
+    toolchain {
+        languageVersion = JavaLanguageVersion.of(javaVersion)
+    }
+}
+
+compileKotlin {
+    kotlinOptions {
+        jvmTarget = javaVersion
+    }
+}
+
+compileTestKotlin {
+    kotlinOptions {
+        jvmTarget = javaVersion
+    }
+}
+
+dependencies {
+    // should have no dependencies to other modules
+    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8"
+    implementation "com.michael-bull.kotlin-result:kotlin-result-jvm:1.1.16"
+}
+
+sourceSets {
+    main {
+        java {
+            srcDirs = ["${project.projectDir}/src"]
+        }
+        resources {
+            srcDirs = ["${project.projectDir}/res"]
+        }
+    }
+}
+
+// note: there are no unit tests in this module!

codeCore/codeCore.iml

@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<module type="JAVA_MODULE" version="4">
+  <component name="NewModuleRootManager" inherit-compiler-output="true">
+    <exclude-output />
+    <content url="file://$MODULE_DIR$">
+      <sourceFolder url="file://$MODULE_DIR$/src" isTestSource="false" />
+      <excludeFolder url="file://$MODULE_DIR$/build" />
+    </content>
+    <orderEntry type="inheritedJdk" />
+    <orderEntry type="sourceFolder" forTests="false" />
+    <orderEntry type="library" name="KotlinJavaRuntime" level="project" />
+    <orderEntry type="library" name="michael.bull.kotlin.result.jvm" level="project" />
+  </component>
+</module>

codeCore/src/prog8/code/SymbolTable.kt

@@ -0,0 +1,258 @@
+package prog8.code
+
+import prog8.code.core.*
+
+
+/**
+ * Tree structure containing all symbol definitions in the program
+ * (blocks, subroutines, variables (all types), memoryslabs, and labels).
+ */
+class SymbolTable : StNode("", StNodeType.GLOBAL, Position.DUMMY) {
+    fun print() = printIndented(0)
+
+    override fun printProperties() { }
+
+    /**
+     * The table as a flat mapping of scoped names to the StNode.
+     * This gives the fastest lookup possible (no need to traverse tree nodes)
+     */
+    val flat: Map<List<String>, StNode> by lazy {
+        val result = mutableMapOf<List<String>, StNode>()
+        fun flatten(node: StNode) {
+            result[node.scopedName] = node
+            node.children.values.forEach { flatten(it) }
+        }
+        children.values.forEach { flatten(it) }
+        result
+    }
+
+    val allVariables: Collection<StStaticVariable> by lazy {
+        val vars = mutableListOf<StStaticVariable>()
+        fun collect(node: StNode) {
+            for(child in node.children) {
+                if(child.value.type== StNodeType.STATICVAR)
+                    vars.add(child.value as StStaticVariable)
+                else
+                    collect(child.value)
+            }
+        }
+        collect(this)
+        vars
+    }
+
+    val allMemMappedVariables: Collection<StMemVar> by lazy {
+        val vars = mutableListOf<StMemVar>()
+        fun collect(node: StNode) {
+            for(child in node.children) {
+                if(child.value.type== StNodeType.MEMVAR)
+                    vars.add(child.value as StMemVar)
+                else
+                    collect(child.value)
+            }
+        }
+        collect(this)
+        vars
+    }
+
+    val allMemorySlabs: Collection<StMemorySlab> by lazy {
+        children.mapNotNull { if (it.value.type == StNodeType.MEMORYSLAB) it.value as StMemorySlab else null }
+    }
+
+    override fun lookup(scopedName: List<String>) = flat[scopedName]
+}
+
+
+enum class StNodeType {
+    GLOBAL,
+    // MODULE,     // not used with current scoping rules
+    BLOCK,
+    SUBROUTINE,
+    ROMSUB,
+    LABEL,
+    STATICVAR,
+    MEMVAR,
+    CONSTANT,
+    BUILTINFUNC,
+    MEMORYSLAB
+}
+
+
+open class StNode(val name: String,
+                  val type: StNodeType,
+                  val position: Position,
+                  val children: MutableMap<String, StNode> = mutableMapOf()
+) {
+
+    lateinit var parent: StNode
+
+    val scopedName: List<String> by lazy {
+        if(type== StNodeType.GLOBAL)
+            emptyList()
+        else
+            parent.scopedName + name
+    }
+
+    fun lookup(name: String) =
+        lookupUnqualified(name)
+    open fun lookup(scopedName: List<String>) =
+        if(scopedName.size>1) lookupQualified(scopedName) else lookupUnqualified(scopedName[0])
+    fun lookupOrElse(name: String, default: () -> StNode) =
+        lookupUnqualified(name) ?: default()
+    fun lookupOrElse(scopedName: List<String>, default: () -> StNode) =
+        lookup(scopedName) ?: default()
+
+    private fun lookupQualified(scopedName: List<String>): StNode? {
+        // a scoped name refers to a name in another namespace, and always stars from the root.
+        var node = this
+        while(node.type!= StNodeType.GLOBAL)
+            node = node.parent
+
+        for(name in scopedName) {
+            if(name in node.children)
+                node = node.children.getValue(name)
+            else
+                return null
+        }
+        return node
+    }
+
+    private fun lookupUnqualified(name: String): StNode? {
+        // first consider the builtin functions
+        var globalscope = this
+        while(globalscope.type!= StNodeType.GLOBAL)
+            globalscope = globalscope.parent
+        val globalNode = globalscope.children[name]
+        if(globalNode!=null && globalNode.type== StNodeType.BUILTINFUNC)
+            return globalNode
+
+        // search for the unqualified name in the current scope or its parent scopes
+        var scope=this
+        while(true) {
+            val node = scope.children[name]
+            if(node!=null)
+                return node
+            if(scope.type== StNodeType.GLOBAL)
+                return null
+            else
+                scope = scope.parent
+        }
+    }
+
+    fun printIndented(indent: Int) {
+        print("    ".repeat(indent))
+        when(type) {
+            StNodeType.GLOBAL -> print("SYMBOL-TABLE:")
+            StNodeType.BLOCK -> print("(B) ")
+            StNodeType.SUBROUTINE -> print("(S) ")
+            StNodeType.LABEL -> print("(L) ")
+            StNodeType.STATICVAR -> print("(V) ")
+            StNodeType.MEMVAR -> print("(M) ")
+            StNodeType.MEMORYSLAB -> print("(MS) ")
+            StNodeType.CONSTANT -> print("(C) ")
+            StNodeType.BUILTINFUNC -> print("(F) ")
+            StNodeType.ROMSUB -> print("(R) ")
+        }
+        printProperties()
+        println()
+        children.forEach { (_, node) -> node.printIndented(indent+1) }
+    }
+
+    open fun printProperties() {
+        print("$name  ")
+    }
+
+    fun add(child: StNode) {
+        children[child.name] = child
+        child.parent = this
+    }
+}
+
+class StStaticVariable(name: String,
+                       val dt: DataType,
+                       val onetimeInitializationNumericValue: Double?,      // regular (every-run-time) initialization is done via regular assignments
+                       val onetimeInitializationStringValue: StString?,
+                       val onetimeInitializationArrayValue: StArray?,
+                       val length: Int?,             // for arrays: the number of elements, for strings: number of characters *including* the terminating 0-byte
+                       val zpwish: ZeropageWish,
+                       position: Position) : StNode(name, StNodeType.STATICVAR, position) {
+
+    init {
+        if(length!=null) {
+            require(onetimeInitializationNumericValue == null)
+            if(onetimeInitializationArrayValue!=null)
+                require(length == onetimeInitializationArrayValue.size)
+        }
+        if(onetimeInitializationNumericValue!=null)
+            require(dt in NumericDatatypes)
+        if(onetimeInitializationArrayValue!=null)
+            require(dt in ArrayDatatypes)
+        if(onetimeInitializationStringValue!=null) {
+            require(dt == DataType.STR)
+            require(length == onetimeInitializationStringValue.first.length+1)
+        }
+    }
+
+    override fun printProperties() {
+        print("$name  dt=$dt  zpw=$zpwish")
+    }
+}
+
+
+class StConstant(name: String, val dt: DataType, val value: Double, position: Position) :
+    StNode(name, StNodeType.CONSTANT, position) {
+    override fun printProperties() {
+        print("$name  dt=$dt value=$value")
+    }
+}
+
+
+class StMemVar(name: String,
+               val dt: DataType,
+               val address: UInt,
+               val length: Int?,             // for arrays: the number of elements, for strings: number of characters *including* the terminating 0-byte
+               position: Position) :
+    StNode(name, StNodeType.MEMVAR, position) {
+    override fun printProperties() {
+        print("$name  dt=$dt address=${address.toHex()}")
+    }
+}
+
+class StMemorySlab(
+    name: String,
+    val size: UInt,
+    val align: UInt,
+    val allocatedAddress: UInt? = null,     // this is used (for now) in the VM code generator. TODO remove this once no longer used
+    position: Position
+):
+    StNode(name, StNodeType.MEMORYSLAB, position) {
+    override fun printProperties() {
+        print("$name  size=$size  align=$align  address=$allocatedAddress")
+    }
+}
+
+class StSub(name: String, val parameters: List<StSubroutineParameter>, val returnType: DataType?, position: Position) :
+        StNode(name, StNodeType.SUBROUTINE, position) {
+    override fun printProperties() {
+        print(name)
+    }
+}
+
+
+class StRomSub(name: String,
+               val address: UInt,
+               val parameters: List<StRomSubParameter>,
+               val returns: List<RegisterOrStatusflag>,
+               position: Position) :
+    StNode(name, StNodeType.ROMSUB, position) {
+    override fun printProperties() {
+        print("$name  address=${address.toHex()}")
+    }
+}
+
+
+class StSubroutineParameter(val name: String, val type: DataType)
+class StRomSubParameter(val register: RegisterOrStatusflag, val type: DataType)
+class StArrayElement(val number: Double?, val addressOf: List<String>?)
+
+typealias StString = Pair<String, Encoding>
+typealias StArray = List<StArrayElement>

codeCore/src/prog8/code/ast/AstBase.kt

@@ -0,0 +1,144 @@
+package prog8.code.ast
+
+import prog8.code.core.*
+import java.nio.file.Path
+
+// New simplified AST for the code generator.
+
+
+sealed class PtNode(val position: Position) {
+
+    val children = mutableListOf<PtNode>()
+    lateinit var parent: PtNode
+
+    fun printIndented(indent: Int) {
+        print("    ".repeat(indent))
+        print("${this.javaClass.simpleName}  ")
+        printProperties()
+        println()
+        children.forEach { it.printIndented(indent+1) }
+    }
+
+    abstract fun printProperties()
+
+    fun add(child: PtNode) {
+        children.add(child)
+        child.parent = this
+    }
+
+    fun add(index: Int, child: PtNode) {
+        children.add(index, child)
+        child.parent = this
+    }
+
+    fun definingBlock() = findParentNode<PtBlock>(this)
+    fun definingSub() = findParentNode<PtSub>(this)
+    fun definingAsmSub() = findParentNode<PtAsmSub>(this)
+}
+
+
+class PtNodeGroup : PtNode(Position.DUMMY) {
+    override fun printProperties() {}
+}
+
+
+abstract class PtNamedNode(val name: String, position: Position): PtNode(position) {
+    val scopedName: List<String> by lazy {
+        var namedParent: PtNode = this.parent
+        if(namedParent is PtProgram)
+            listOf(name)
+        else {
+            while (namedParent !is PtNamedNode)
+                namedParent = namedParent.parent
+            namedParent.scopedName + name
+        }
+    }
+}
+
+
+class PtProgram(
+    val name: String,
+    val memsizer: IMemSizer,
+    val encoding: IStringEncoding
+) : PtNode(Position.DUMMY) {
+    fun print() = printIndented(0)
+    override fun printProperties() {
+        print("'$name'")
+    }
+
+//    fun allModuleDirectives(): Sequence<PtDirective> =
+//        children.asSequence().flatMap { it.children }.filterIsInstance<PtDirective>().distinct()
+
+    fun allBlocks(): Sequence<PtBlock> =
+        children.asSequence().filterIsInstance<PtBlock>()
+
+    fun entrypoint(): PtSub? =
+        allBlocks().firstOrNull { it.name == "main" }?.children?.firstOrNull { it is PtSub && it.name == "start" } as PtSub?
+}
+
+
+class PtBlock(name: String,
+              val address: UInt?,
+              val library: Boolean,
+              val forceOutput: Boolean,
+              val alignment: BlockAlignment,
+              position: Position
+) : PtNamedNode(name, position) {
+    override fun printProperties() {
+        print("$name  addr=$address  library=$library  forceOutput=$forceOutput  alignment=$alignment")
+    }
+
+    enum class BlockAlignment {
+        NONE,
+        WORD,
+        PAGE
+    }
+}
+
+
+class PtInlineAssembly(val assembly: String, position: Position) : PtNode(position) {
+    override fun printProperties() {}
+}
+
+
+class PtLabel(name: String, position: Position) : PtNamedNode(name, position) {
+    override fun printProperties() {
+        print(name)
+    }
+}
+
+
+class PtBreakpoint(position: Position): PtNode(position) {
+    override fun printProperties() {}
+}
+
+
+class PtIncludeBinary(val file: Path, val offset: UInt?, val length: UInt?, position: Position) : PtNode(position) {
+    override fun printProperties() {
+        print("filename=$file  offset=$offset  length=$length")
+    }
+}
+
+
+class PtNop(position: Position): PtNode(position) {
+    override fun printProperties() {}
+}
+
+
+class PtScopeVarsDecls(position: Position): PtNode(position) {
+    override fun printProperties() {}
+}
+
+
+
+// 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: PtNode): T? {
+    var candidate = node.parent
+    while(candidate !is T && candidate !is PtProgram)
+        candidate = candidate.parent
+    return if(candidate is PtProgram)
+        null
+    else
+        candidate as T
+}

codeCore/src/prog8/code/ast/AstExpressions.kt

@@ -0,0 +1,227 @@
+package prog8.code.ast
+
+import prog8.code.core.DataType
+import prog8.code.core.Encoding
+import prog8.code.core.Position
+import java.util.*
+import kotlin.math.round
+
+
+sealed class PtExpression(val type: DataType, position: Position) : PtNode(position) {
+
+    init {
+        if(type==DataType.BOOL)
+            throw IllegalArgumentException("bool should have become ubyte @$position")
+        if(type==DataType.UNDEFINED) {
+            @Suppress("LeakingThis")
+            when(this) {
+                is PtBuiltinFunctionCall -> { /* void function call */ }
+                is PtFunctionCall -> { /* void function call */ }
+                is PtIdentifier -> { /* non-variable identifier */ }
+                else -> throw IllegalArgumentException("type should be known @$position")
+            }
+        }
+    }
+
+    override fun printProperties() {
+        print(type)
+    }
+
+    infix fun isSameAs(other: PtExpression): Boolean {
+        return when(this) {
+            is PtAddressOf -> other is PtAddressOf && other.type==type && other.identifier isSameAs identifier
+            is PtArrayIndexer -> other is PtArrayIndexer && other.type==type && other.variable isSameAs variable && other.index isSameAs index
+            is PtBinaryExpression -> other is PtBinaryExpression && other.left isSameAs left && other.right isSameAs right
+            is PtContainmentCheck -> other is PtContainmentCheck && other.type==type && other.element isSameAs element && other.iterable isSameAs iterable
+            is PtIdentifier -> other is PtIdentifier && other.type==type && other.targetName==targetName
+            is PtMachineRegister -> other is PtMachineRegister && other.type==type && other.register==register
+            is PtMemoryByte -> other is PtMemoryByte && other.address isSameAs address
+            is PtNumber -> other is PtNumber && other.type==type && other.number==number
+            is PtPrefix -> other is PtPrefix && other.type==type && other.operator==operator && other.value isSameAs value
+            is PtRange -> other is PtRange && other.type==type && other.from==from && other.to==to && other.step==step
+            is PtTypeCast -> other is PtTypeCast && other.type==type && other.value isSameAs value
+            else -> false
+        }
+    }
+}
+
+class PtAddressOf(position: Position) : PtExpression(DataType.UWORD, position) {
+    val identifier: PtIdentifier
+        get() = children.single() as PtIdentifier
+}
+
+
+class PtArrayIndexer(type: DataType, position: Position): PtExpression(type, position) {
+    val variable: PtIdentifier
+        get() = children[0] as PtIdentifier
+    val index: PtExpression
+        get() = children[1] as PtExpression
+}
+
+
+class PtArray(type: DataType, position: Position): PtExpression(type, position) {
+    override fun hashCode(): Int = Objects.hash(children, type)
+    override fun equals(other: Any?): Boolean {
+        if(other==null || other !is PtArray)
+            return false
+        return type==other.type && children == other.children
+    }
+}
+
+
+class PtBuiltinFunctionCall(val name: String,
+                            val void: Boolean,
+                            val hasNoSideEffects: Boolean,
+                            type: DataType,
+                            position: Position) : PtExpression(type, position) {
+    init {
+        if(!void)
+            require(type!=DataType.UNDEFINED)
+    }
+
+    val args: List<PtExpression>
+        get() = children.map { it as PtExpression }
+    override fun printProperties() {
+        print("$name void=$void noSideFx=$hasNoSideEffects")
+    }
+}
+
+
+class PtBinaryExpression(val operator: String, type: DataType, position: Position): PtExpression(type, position) {
+    // note: "and", "or", "xor" do not occur anymore as operators. They've been replaced int the ast by their bitwise versions &, |, ^.
+    val left: PtExpression
+        get() = children[0] as PtExpression
+    val right: PtExpression
+        get() = children[1] as PtExpression
+
+    override fun printProperties() {
+        print("$operator -> $type")
+    }
+}
+
+
+class PtContainmentCheck(position: Position): PtExpression(DataType.UBYTE, position) {
+    val element: PtExpression
+        get() = children[0] as PtExpression
+    val iterable: PtIdentifier
+        get() = children[1] as PtIdentifier
+}
+
+
+class PtFunctionCall(val functionName: List<String>,
+                     val void: Boolean,
+                     type: DataType,
+                     position: Position) : PtExpression(type, position) {
+    init {
+        if(!void)
+            require(type!=DataType.UNDEFINED)
+    }
+
+    val args: List<PtExpression>
+        get() = children.map { it as PtExpression }
+    override fun printProperties() {
+        print("${functionName.joinToString(".")} void=$void")
+    }
+}
+
+
+class PtIdentifier(val ref: List<String>, val targetName: List<String>, type: DataType, position: Position) : PtExpression(type, position) {
+    override fun printProperties() {
+        print("$ref --> $targetName  $type")
+    }
+}
+
+
+class PtMemoryByte(position: Position) : PtExpression(DataType.UBYTE, position) {
+    val address: PtExpression
+        get() = children.single() as PtExpression
+    override fun printProperties() {}
+}
+
+
+class PtNumber(type: DataType, val number: Double, position: Position) : PtExpression(type, position) {
+
+    init {
+        if(type==DataType.BOOL)
+            throw IllegalArgumentException("bool should have become ubyte @$position")
+        if(type!=DataType.FLOAT) {
+            val rounded = round(number)
+            if (rounded != number)
+                throw IllegalArgumentException("refused rounding of float to avoid loss of precision @$position")
+        }
+    }
+
+    override fun printProperties() {
+        print("$number ($type)")
+    }
+
+    override fun hashCode(): Int = Objects.hash(type, number)
+
+    override fun equals(other: Any?): Boolean {
+        if(other==null || other !is PtNumber)
+            return false
+        return number==other.number
+    }
+
+    operator fun compareTo(other: PtNumber): Int = number.compareTo(other.number)
+}
+
+
+class PtPrefix(val operator: String, type: DataType, position: Position): PtExpression(type, position) {
+    val value: PtExpression
+        get() = children.single() as PtExpression
+
+    init {
+        // note: the "not" operator may no longer occur in the ast; not x should have been replaced with x==0
+        if(operator !in setOf("+", "-", "~"))
+            throw IllegalArgumentException("invalid prefix operator: $operator")
+    }
+
+    override fun printProperties() {
+        print(operator)
+    }
+}
+
+
+class PtRange(type: DataType, position: Position) : PtExpression(type, position) {
+    val from: PtExpression
+        get() = children[0] as PtExpression
+    val to: PtExpression
+        get() = children[1] as PtExpression
+    val step: PtNumber
+        get() = children[2] as PtNumber
+
+    override fun printProperties() {}
+}
+
+
+class PtString(val value: String, val encoding: Encoding, position: Position) : PtExpression(DataType.STR, position) {
+    override fun printProperties() {
+        print("$encoding:\"$value\"")
+    }
+
+    override fun hashCode(): Int = Objects.hash(value, encoding)
+    override fun equals(other: Any?): Boolean {
+        if(other==null || other !is PtString)
+            return false
+        return value==other.value && encoding == other.encoding
+    }
+}
+
+
+class PtTypeCast(type: DataType, position: Position) : PtExpression(type, position) {
+    val value: PtExpression
+        get() = children.single() as PtExpression
+}
+
+
+// special node that isn't created from compiling user code, but used internally
+class PtMachineRegister(val register: Int, type: DataType, position: Position) : PtExpression(type, position) {
+    override fun printProperties() {
+        print("reg=$register  $type")
+    }
+}
+
+
+fun constValue(expr: PtExpression): Double? = if(expr is PtNumber) expr.number else null
+fun constIntValue(expr: PtExpression): Int? = if(expr is PtNumber) expr.number.toInt() else null

codeCore/src/prog8/code/ast/AstStatements.kt

@@ -0,0 +1,220 @@
+package prog8.code.ast
+
+import prog8.code.core.*
+
+
+class PtAsmSub(
+    name: String,
+    val address: UInt?,
+    val clobbers: Set<CpuRegister>,
+    val parameters: List<Pair<PtSubroutineParameter, RegisterOrStatusflag>>,
+    val returnTypes: List<DataType>,    // TODO join with register as Pairs ?
+    val retvalRegisters: List<RegisterOrStatusflag>,
+    val inline: Boolean,
+    position: Position
+) : PtNamedNode(name, position) {
+    override fun printProperties() {
+        print("$name  inline=$inline")
+    }
+}
+
+
+class PtSub(
+    name: String,
+    val parameters: List<PtSubroutineParameter>,
+    val returntype: DataType?,
+    val inline: Boolean,
+    position: Position
+) : PtNamedNode(name, position) {
+    override fun printProperties() {
+        print(name)
+    }
+}
+
+
+class PtSubroutineParameter(val name: String, val type: DataType, position: Position): PtNode(position) {
+    override fun printProperties() {
+        print("$type $name")
+    }
+}
+
+
+class PtAssignment(position: Position) : PtNode(position) {
+    val target: PtAssignTarget
+        get() = children[0] as PtAssignTarget
+    val value: PtExpression
+        get() = children[1] as PtExpression
+
+    override fun printProperties() { }
+
+    val isInplaceAssign: Boolean by lazy {
+        val target = target.children.single() as PtExpression
+        when(val source = value) {
+            is PtArrayIndexer -> {
+                if(target is PtArrayIndexer && source.type==target.type) {
+                    if(target.variable isSameAs source.variable) {
+                        target.index isSameAs source.index
+                    }
+                }
+                false
+            }
+            is PtIdentifier -> target is PtIdentifier && target.type==source.type && target.targetName==source.targetName
+            is PtMachineRegister -> target is PtMachineRegister && target.register==source.register
+            is PtMemoryByte -> target is PtMemoryByte && target.address isSameAs source.address
+            is PtNumber -> target is PtNumber && target.type == source.type && target.number==source.number
+            is PtAddressOf -> target is PtAddressOf && target.identifier isSameAs source.identifier
+            is PtPrefix -> {
+                (target is PtPrefix && target.operator==source.operator && target.value isSameAs source.value)
+                        ||
+                (target is PtIdentifier && (source.value as? PtIdentifier)?.targetName==target.targetName)
+            }
+            is PtTypeCast -> target is PtTypeCast && target.type==source.type && target.value isSameAs source.value
+            is PtBinaryExpression ->
+                target isSameAs source.left
+            else -> false
+        }
+    }
+}
+
+class PtAssignTarget(position: Position) : PtNode(position) {
+    val identifier: PtIdentifier?
+        get() = children.single() as? PtIdentifier
+    val array: PtArrayIndexer?
+        get() = children.single() as? PtArrayIndexer
+    val memory: PtMemoryByte?
+        get() = children.single() as? PtMemoryByte
+
+    val type: DataType
+        get() {
+            return when(val tgt = children.single()) {
+                is PtIdentifier -> tgt.type
+                is PtArrayIndexer -> tgt.type
+                is PtMemoryByte -> tgt.type
+                else -> throw AssemblyError("weird target $tgt")
+            }
+        }
+
+    override fun printProperties() {}
+}
+
+
+class PtConditionalBranch(val condition: BranchCondition, position: Position) : PtNode(position) {
+    val trueScope: PtNodeGroup
+        get() = children[0] as PtNodeGroup
+    val falseScope: PtNodeGroup
+        get() = children[1] as PtNodeGroup
+
+    override fun printProperties() {
+        print(condition)
+    }
+}
+
+
+class PtForLoop(position: Position) : PtNode(position) {
+    val variable: PtIdentifier
+        get() = children[0] as PtIdentifier
+    val iterable: PtExpression
+        get() = children[1] as PtExpression
+    val statements: PtNodeGroup
+        get() = children[2] as PtNodeGroup
+
+    override fun printProperties() {}
+}
+
+
+class PtIfElse(position: Position) : PtNode(position) {
+    val condition: PtBinaryExpression
+        get() = children[0] as PtBinaryExpression
+    val ifScope: PtNodeGroup
+        get() = children[1] as PtNodeGroup
+    val elseScope: PtNodeGroup
+        get() = children[2] as PtNodeGroup
+
+    override fun printProperties() {}
+}
+
+
+class PtJump(val identifier: PtIdentifier?,
+             val address: UInt?,
+             val generatedLabel: String?,
+             position: Position) : PtNode(position) {
+    override fun printProperties() {
+        identifier?.printProperties()
+        if(address!=null) print(address.toHex())
+        if(generatedLabel!=null) print(generatedLabel)
+    }
+}
+
+
+class PtPostIncrDecr(val operator: String, position: Position) : PtNode(position) {
+    val target: PtAssignTarget
+        get() = children.single() as PtAssignTarget
+
+    override fun printProperties() {
+        print(operator)
+    }
+}
+
+
+class PtRepeatLoop(position: Position) : PtNode(position) {
+    val count: PtExpression
+        get() = children[0] as PtExpression
+    val statements: PtNodeGroup
+        get() = children[1] as PtNodeGroup
+
+    override fun printProperties() {}
+}
+
+
+class PtReturn(position: Position) : PtNode(position) {
+    val hasValue = children.any()
+    val value: PtExpression?
+        get() {
+            return if(children.any())
+                children.single() as PtExpression
+            else
+                null
+        }
+
+    override fun printProperties() {}
+}
+
+
+class PtVariable(name: String, val type: DataType, var value: PtExpression?, var arraySize: UInt?, position: Position) : PtNamedNode(name, position) {
+    override fun printProperties() {
+        print("$type  $name")
+    }
+}
+
+
+class PtConstant(name: String, val type: DataType, val value: Double, position: Position) : PtNamedNode(name, position) {
+    override fun printProperties() {
+        print("$type $name = $value")
+    }
+}
+
+
+class PtMemMapped(name: String, val type: DataType, val address: UInt, position: Position) : PtNamedNode(name, position) {
+    override fun printProperties() {
+        print("&$type $name = ${address.toHex()}")
+    }
+}
+
+
+class PtWhen(position: Position) : PtNode(position) {
+    val value: PtExpression
+        get() = children[0] as PtExpression
+    val choices: PtNodeGroup
+        get() = children[1] as PtNodeGroup
+
+    override fun printProperties() {}
+}
+
+
+class PtWhenChoice(val isElse: Boolean, position: Position) : PtNode(position) {
+    val values: PtNodeGroup
+        get() = children[0] as PtNodeGroup
+    val statements: PtNodeGroup
+        get() = children[1] as PtNodeGroup
+    override fun printProperties() {}
+}

codeCore/src/prog8/code/core/CompilationOptions.kt

@@ -0,0 +1,27 @@
+package prog8.code.core
+
+import java.nio.file.Path
+import kotlin.io.path.Path
+
+
+class CompilationOptions(val output: OutputType,
+                         val launcher: CbmPrgLauncherType,
+                         val zeropage: ZeropageType,
+                         val zpReserved: List<UIntRange>,
+                         val floats: Boolean,
+                         val noSysInit: Boolean,
+                         val compTarget: ICompilationTarget,
+                         // these are set later, based on command line arguments or options in the source code:
+                         var loadAddress: UInt,
+                         var slowCodegenWarnings: Boolean = false,
+                         var optimize: Boolean = false,
+                         var optimizeFloatExpressions: Boolean = false,
+                         var dontReinitGlobals: Boolean = false,
+                         var asmQuiet: Boolean = false,
+                         var asmListfile: Boolean = false,
+                         var experimentalCodegen: Boolean = false,
+                         var keepIR: Boolean = false,
+                         var evalStackBaseAddress: UInt? = null,
+                         var outputDir: Path = Path(""),
+                         var symbolDefs: Map<String, String> = emptyMap()
+)

codeCore/src/prog8/code/core/Conversions.kt

@@ -0,0 +1,89 @@
+package prog8.code.core
+
+import kotlin.math.abs
+
+fun Number.toHex(): String {
+    //  0..15 -> "0".."15"
+    //  16..255 -> "$10".."$ff"
+    //  256..65536 -> "$0100".."$ffff"
+    // negative values are prefixed with '-'.
+    val integer = this.toInt()
+    if(integer<0)
+        return '-' + abs(integer).toHex()
+    return when (integer) {
+        in 0 until 16 -> integer.toString()
+        in 0 until 0x100 -> "$"+integer.toString(16).padStart(2,'0')
+        in 0 until 0x10000 -> "$"+integer.toString(16).padStart(4,'0')
+        else -> throw IllegalArgumentException("number too large for 16 bits $this")
+    }
+}
+
+fun UInt.toHex(): String {
+    //  0..15 -> "0".."15"
+    //  16..255 -> "$10".."$ff"
+    //  256..65536 -> "$0100".."$ffff"
+    return when (this) {
+        in 0u until 16u -> this.toString()
+        in 0u until 0x100u -> "$"+this.toString(16).padStart(2,'0')
+        in 0u until 0x10000u -> "$"+this.toString(16).padStart(4,'0')
+        else -> throw IllegalArgumentException("number too large for 16 bits $this")
+    }
+}
+
+fun Char.escape(): Char = this.toString().escape()[0]
+
+fun String.escape(): String {
+    val es = this.map {
+        when(it) {
+            '\t' -> "\\t"
+            '\n' -> "\\n"
+            '\r' -> "\\r"
+            '"' -> "\\\""
+            in '\u8000'..'\u80ff' -> "\\x" + (it.code - 0x8000).toString(16).padStart(2, '0')       // 'ugly' passthrough hack
+            in '\u0000'..'\u00ff' -> it.toString()
+            else -> "\\u" + it.code.toString(16).padStart(4, '0')
+        }
+    }
+    return es.joinToString("")
+}
+
+fun String.unescape(): String {
+    val result = mutableListOf<Char>()
+    val iter = this.iterator()
+    while(iter.hasNext()) {
+        val c = iter.nextChar()
+        if(c=='\\') {
+            val ec = iter.nextChar()
+            result.add(when(ec) {
+                '\\' -> '\\'
+                'n' -> '\n'
+                'r' -> '\r'
+                '"' -> '"'
+                '\'' -> '\''
+                'u' -> {
+                    try {
+                        "${iter.nextChar()}${iter.nextChar()}${iter.nextChar()}${iter.nextChar()}".toInt(16).toChar()
+                    } catch (sb: StringIndexOutOfBoundsException) {
+                        throw IllegalArgumentException("invalid \\u escape sequence")
+                    } catch (nf: NumberFormatException) {
+                        throw IllegalArgumentException("invalid \\u escape sequence")
+                    }
+                }
+                'x' -> {
+                    try {
+                        val hex = ("" + iter.nextChar() + iter.nextChar()).toInt(16)
+                        (0x8000 + hex).toChar()         // 'ugly' pass-through hack
+                    } catch (sb: StringIndexOutOfBoundsException) {
+                        throw IllegalArgumentException("invalid \\x escape sequence")
+                    } catch (nf: NumberFormatException) {
+                        throw IllegalArgumentException("invalid \\x escape sequence")
+                    }
+                }
+                else -> throw IllegalArgumentException("invalid escape char in string: \\$ec")
+            })
+        } else {
+            result.add(c)
+        }
+    }
+    return result.joinToString("")
+}

codeCore/src/prog8/code/core/Enumerations.kt

@@ -0,0 +1,182 @@
+package prog8.code.core
+
+enum class DataType {
+    UBYTE,              // pass by value
+    BYTE,               // pass by value
+    UWORD,              // pass by value
+    WORD,               // pass by value
+    FLOAT,              // pass by value
+    BOOL,               // 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
+    ARRAY_BOOL,         // pass by reference
+    UNDEFINED;
+
+    /**
+     * is the type assignable to the given other type (perhaps via a typecast) without loss of precision?
+     */
+    infix fun isAssignableTo(targetType: DataType) =
+        when(this) {
+            BOOL -> targetType.oneOf(BOOL, BYTE, UBYTE, WORD, UWORD, FLOAT)
+            UBYTE -> targetType.oneOf(UBYTE, WORD, UWORD, FLOAT, BOOL)
+            BYTE -> targetType.oneOf(BYTE, WORD, FLOAT)
+            UWORD -> targetType.oneOf(UWORD, FLOAT)
+            WORD -> targetType.oneOf(WORD, FLOAT)
+            FLOAT -> targetType.oneOf(FLOAT)
+            STR -> targetType.oneOf(STR, UWORD)
+            in ArrayDatatypes -> targetType == this
+            else -> false
+        }
+
+    fun oneOf(vararg types: DataType) = this in types
+
+    infix fun largerThan(other: DataType) =
+        when {
+            this == other -> false
+            this in ByteDatatypes -> false
+            this in WordDatatypes -> other in ByteDatatypes
+            this== STR && other== UWORD || this== UWORD && other== STR -> false
+            else -> true
+        }
+
+    infix fun equalsSize(other: DataType) =
+        when {
+            this == other -> true
+            this in ByteDatatypes -> other in ByteDatatypes
+            this in WordDatatypes -> other in WordDatatypes
+            this== STR && other== UWORD || this== UWORD && other== STR -> true
+            else -> false
+        }
+}
+
+enum class CpuRegister {
+    A,
+    X,
+    Y
+}
+
+enum class RegisterOrPair {
+    A,
+    X,
+    Y,
+    AX,
+    AY,
+    XY,
+    FAC1,
+    FAC2,
+    // cx16 virtual registers:
+    R0, R1, R2, R3, R4, R5, R6, R7,
+    R8, R9, R10, R11, R12, R13, R14, R15;
+
+    companion object {
+        val names by lazy { values().map { it.toString()} }
+    }
+
+    fun asCpuRegister(): CpuRegister = when(this) {
+        A -> CpuRegister.A
+        X -> CpuRegister.X
+        Y -> CpuRegister.Y
+        else -> throw IllegalArgumentException("no cpu hardware register for $this")
+    }
+
+}       // only used in parameter and return value specs in asm subroutines
+
+enum class Statusflag {
+    Pc,
+    Pz,     // don't use
+    Pv,
+    Pn;     // don't use
+
+    companion object {
+        val names by lazy { values().map { it.toString()} }
+    }
+}
+
+enum class BranchCondition {
+    CS,
+    CC,
+    EQ,     // EQ == Z
+    Z,
+    NE,     // NE == NZ
+    NZ,
+    MI,     // MI == NEG
+    NEG,
+    PL,     // PL == POS
+    POS,
+    VS,
+    VC,
+}
+
+
+val ByteDatatypes = arrayOf(DataType.UBYTE, DataType.BYTE, DataType.BOOL)
+val WordDatatypes = arrayOf(DataType.UWORD, DataType.WORD)
+val IntegerDatatypes = arrayOf(DataType.UBYTE, DataType.BYTE, DataType.UWORD, DataType.WORD, DataType.BOOL)
+val IntegerDatatypesNoBool = arrayOf(DataType.UBYTE, DataType.BYTE, DataType.UWORD, DataType.WORD)
+val NumericDatatypes = arrayOf(DataType.UBYTE, DataType.BYTE, DataType.UWORD, DataType.WORD, DataType.FLOAT, DataType.BOOL)
+val NumericDatatypesNoBool = arrayOf(DataType.UBYTE, DataType.BYTE, DataType.UWORD, DataType.WORD, DataType.FLOAT)
+val SignedDatatypes =  arrayOf(DataType.BYTE, DataType.WORD, DataType.FLOAT)
+val ArrayDatatypes = arrayOf(DataType.ARRAY_UB, DataType.ARRAY_B, DataType.ARRAY_UW, DataType.ARRAY_W, DataType.ARRAY_F, DataType.ARRAY_BOOL)
+val StringlyDatatypes = arrayOf(DataType.STR, DataType.ARRAY_UB, DataType.ARRAY_B, DataType.UWORD)
+val IterableDatatypes = arrayOf(
+    DataType.STR,
+    DataType.ARRAY_UB, DataType.ARRAY_B,
+    DataType.ARRAY_UW, DataType.ARRAY_W,
+    DataType.ARRAY_F, DataType.ARRAY_BOOL
+)
+val PassByValueDatatypes = NumericDatatypes
+val PassByReferenceDatatypes = IterableDatatypes
+val ArrayToElementTypes = 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,
+    DataType.ARRAY_BOOL to DataType.BOOL
+)
+val ElementToArrayTypes = 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,
+    DataType.BOOL to DataType.ARRAY_BOOL
+)
+val Cx16VirtualRegisters = arrayOf(
+    RegisterOrPair.R0, RegisterOrPair.R1, RegisterOrPair.R2, RegisterOrPair.R3,
+    RegisterOrPair.R4, RegisterOrPair.R5, RegisterOrPair.R6, RegisterOrPair.R7,
+    RegisterOrPair.R8, RegisterOrPair.R9, RegisterOrPair.R10, RegisterOrPair.R11,
+    RegisterOrPair.R12, RegisterOrPair.R13, RegisterOrPair.R14, RegisterOrPair.R15
+)
+
+
+
+enum class OutputType {
+    RAW,
+    PRG,
+    XEX
+}
+
+enum class CbmPrgLauncherType {
+    BASIC,
+    NONE
+}
+
+enum class ZeropageType {
+    BASICSAFE,
+    FLOATSAFE,
+    KERNALSAFE,
+    FULL,
+    DONTUSE
+}
+
+enum class ZeropageWish {
+    REQUIRE_ZEROPAGE,
+    PREFER_ZEROPAGE,
+    DONTCARE,
+    NOT_IN_ZEROPAGE
+}

codeCore/src/prog8/code/core/Exceptions.kt

@@ -0,0 +1,7 @@
+package prog8.code.core
+
+class InternalCompilerException(message: String?) : Exception(message)
+
+class AssemblyError(msg: String) : RuntimeException(msg)
+
+class ErrorsReportedException(message: String?) : Exception(message)

codeCore/src/prog8/code/core/IAssemblyGenerator.kt

@@ -0,0 +1,12 @@
+package prog8.code.core
+
+interface IAssemblyGenerator {
+    fun compileToAssembly(): IAssemblyProgram?
+}
+
+interface IAssemblyProgram {
+    val name: String
+    fun assemble(options: CompilationOptions): Boolean
+}
+
+fun viceMonListName(baseFilename: String) = "$baseFilename.vice-mon-list"

codeCore/src/prog8/code/core/ICompilationTarget.kt

@@ -0,0 +1,11 @@
+package prog8.code.core
+
+interface ICompilationTarget: IStringEncoding, IMemSizer {
+    val name: String
+    val machine: IMachineDefinition
+    val supportedEncodings: Set<Encoding>
+    val defaultEncoding: Encoding
+
+    override fun encodeString(str: String, encoding: Encoding): List<UByte>
+    override fun decodeString(bytes: List<UByte>, encoding: Encoding): String
+}

codeCore/src/prog8/code/core/IErrorReporter.kt

@@ -0,0 +1,12 @@
+package prog8.code.core
+
+interface IErrorReporter {
+    fun err(msg: String, position: Position)
+    fun warn(msg: String, position: Position)
+    fun noErrors(): Boolean
+    fun report()
+    fun finalizeNumErrors(numErrors: Int, numWarnings: Int) {
+        if(numErrors>0)
+            throw ErrorsReportedException("There are $numErrors errors and $numWarnings warnings.")
+    }
+}

codeCore/src/prog8/code/core/IMachineDefinition.kt

@@ -0,0 +1,35 @@
+package prog8.code.core
+
+import java.nio.file.Path
+
+
+enum class CpuType {
+    CPU6502,
+    CPU65c02,
+    VIRTUAL
+}
+
+interface IMachineDefinition {
+    val FLOAT_MAX_NEGATIVE: Double
+    val FLOAT_MAX_POSITIVE: Double
+    val FLOAT_MEM_SIZE: Int
+    var ESTACK_LO: UInt
+    var ESTACK_HI: UInt
+    val PROGRAM_LOAD_ADDRESS : UInt
+
+    val opcodeNames: Set<String>
+    var zeropage: Zeropage
+    val cpu: CpuType
+
+    fun initializeZeropage(compilerOptions: CompilationOptions)
+    fun getFloatAsmBytes(num: Number): String
+
+    fun importLibs(compilerOptions: CompilationOptions, compilationTargetName: String): List<String>
+    fun launchEmulator(selectedEmulator: Int, programNameWithPath: Path)
+    fun isIOAddress(address: UInt): Boolean
+    fun overrideEvalStack(evalStackBaseAddress: UInt) {
+        require(evalStackBaseAddress and 255u == 0u)
+        ESTACK_LO = evalStackBaseAddress
+        ESTACK_HI = evalStackBaseAddress + 256u
+    }
+}

codeCore/src/prog8/code/core/IMemSizer.kt

@@ -0,0 +1,6 @@
+package prog8.code.core
+
+interface IMemSizer {
+    fun memorySize(dt: DataType): Int
+    fun memorySize(arrayDt: DataType, numElements: Int): Int
+}

codeCore/src/prog8/code/core/IStringEncoding.kt

@@ -0,0 +1,14 @@
+package prog8.code.core
+
+enum class Encoding(val prefix: String) {
+    DEFAULT("default"),         // depends on compilation target
+    PETSCII("petscii"),         // c64/c128/cx16
+    SCREENCODES("sc"),          // c64/c128/cx16
+    ATASCII("atascii"),         // atari
+    ISO("iso")                  // cx16
+}
+
+interface IStringEncoding {
+    fun encodeString(str: String, encoding: Encoding): List<UByte>
+    fun decodeString(bytes: List<UByte>, encoding: Encoding): String
+}

codeCore/src/prog8/code/core/Operators.kt

@@ -0,0 +1,19 @@
+package prog8.code.core
+
+val AssociativeOperators = setOf("+", "*", "&", "|", "^", "==", "!=")
+val ComparisonOperators = setOf("==", "!=", "<", ">", "<=", ">=")
+val LogicalOperators = setOf("and", "or", "xor", "not")
+val AugmentAssignmentOperators = setOf("+", "-", "/", "*", "&", "|", "^", "<<", ">>", "%", "and", "or", "xor")
+val BitwiseOperators = setOf("&", "|", "^", "~")
+// val InvalidOperatorsForBoolean = setOf("+", "-", "*", "/", "%", "<<", ">>") + BitwiseOperators
+
+fun invertedComparisonOperator(operator: String) =
+    when (operator) {
+        "==" -> "!="
+        "!=" -> "=="
+        "<" -> ">="
+        ">" -> "<="
+        "<=" -> ">"
+        ">=" -> "<"
+        else -> null
+    }

codeCore/src/prog8/code/core/Position.kt

@@ -0,0 +1,22 @@
+package prog8.code.core
+
+import java.nio.file.InvalidPathException
+import kotlin.io.path.Path
+import kotlin.io.path.absolute
+
+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}]"
+    fun toClickableStr(): String {
+        return try {
+            val path = Path(file).absolute().normalize().toString()
+            "file://$path:$line:$startCol:"
+        } catch(x: InvalidPathException) {
+            // this can occur on Windows when the source origin contains "invalid" characters such as ':'
+            "file://$file:$line:$startCol:"
+        }
+    }
+
+    companion object {
+        val DUMMY = Position("~dummy~", 0, 0, 0)
+    }
+}

codeCore/src/prog8/code/core/RegisterOrStatusflag.kt

@@ -0,0 +1,3 @@
+package prog8.code.core
+
+data class RegisterOrStatusflag(val registerOrPair: RegisterOrPair?, val statusflag: Statusflag?)

codeCore/src/prog8/code/core/SourceCode.kt

@@ -0,0 +1,141 @@
+package prog8.code.core
+
+import java.io.File
+import java.io.IOException
+import java.nio.file.Path
+import kotlin.io.path.Path
+import kotlin.io.path.readText
+
+
+const val internedStringsModuleName = "prog8_interned_strings"
+
+
+/**
+ * Encapsulates - and ties together - actual source code (=text) and its [origin].
+ */
+sealed class SourceCode {
+
+    /**
+     * Whether this [SourceCode] instance was created as a [Resource]
+     */
+    abstract val isFromResources: Boolean
+
+    /**
+     * Whether this [SourceCode] instance was created as a [File]
+     */
+    abstract val isFromFilesystem: Boolean
+
+    /**
+     * The logical name of the source code unit. Usually the module's name.
+     */
+    abstract val name: String
+
+    /**
+     * Where this [SourceCode] instance came from.
+     * This can be one of the following:
+     * * a normal string representation of a [java.nio.file.Path], if it originates from a file (see [File])
+     * * `string:44c56085` if was created via [String]
+     * * `library:/x/y/z.ext` if it is a library file that was loaded from resources (see [Resource])
+     */
+    abstract val origin: String
+
+    /**
+     * The source code as plain string.
+     */
+    abstract val text: String
+
+    /**
+     * Printable representation, deliberately does NOT return the actual text.
+     */
+    final override fun toString() = "${this.javaClass.name}[${this.origin}]"
+
+    companion object {
+
+        /**
+         * filename prefix to designate library files that will be retreived from internal resources rather than disk
+         */
+        const val libraryFilePrefix = "library:"
+        const val stringSourcePrefix = "string:"
+        val curdir: Path = Path(".").toAbsolutePath()
+        fun relative(path: Path): Path = curdir.relativize(path.toAbsolutePath())
+        fun isRegularFilesystemPath(pathString: String) =
+            !(pathString.startsWith(libraryFilePrefix) || pathString.startsWith(stringSourcePrefix))
+    }
+
+    /**
+     * Turn a plain String into a [SourceCode] object.
+     * [origin] will be something like `string:44c56085`.
+     */
+    class Text(override val text: String): SourceCode() {
+        override val isFromResources = false
+        override val isFromFilesystem = false
+        override val origin = "$stringSourcePrefix${System.identityHashCode(text).toString(16)}"
+        override val name = "<unnamed-text>"
+    }
+
+    /**
+     * Get [SourceCode] from the file represented by the specified Path.
+     * This immediately reads the file fully into memory.
+     *
+     * [origin] will be the given path in absolute and normalized form.
+     * @throws NoSuchFileException if the file does not exist
+     * @throws FileSystemException if the file cannot be read
+     */
+    class File(path: Path): SourceCode() {
+        override val text: String
+        override val origin: String
+        override val name: String
+        override val isFromResources = false
+        override val isFromFilesystem = true
+
+        init {
+            val normalized = path.normalize()
+            origin = relative(normalized).toString()
+            try {
+                text = normalized.readText()
+                name = normalized.toFile().nameWithoutExtension
+            } catch (nfx: java.nio.file.NoSuchFileException) {
+                throw NoSuchFileException(normalized.toFile()).also { it.initCause(nfx) }
+            } catch (iox: IOException) {
+                throw FileSystemException(normalized.toFile()).also { it.initCause(iox) }
+            }
+        }
+    }
+
+    /**
+     * [origin]: `library:/x/y/z.p8` for a given `pathString` of "x/y/z.p8"
+     */
+    class Resource(pathString: String): SourceCode() {
+        private val normalized = "/" + Path.of(pathString).normalize().toMutableList().joinToString("/")
+
+        override val isFromResources = true
+        override val isFromFilesystem = false
+        override val origin = "$libraryFilePrefix$normalized"
+        override val text: String
+        override val name: String
+
+        init {
+            val rscURL = object {}.javaClass.getResource(normalized)
+            if (rscURL == null) {
+                val rscRoot = object {}.javaClass.getResource("/")
+                throw NoSuchFileException(
+                    File(normalized),
+                    reason = "looked in resources rooted at $rscRoot"
+                )
+            }
+            val stream = object {}.javaClass.getResourceAsStream(normalized)
+            text = stream!!.reader().use { it.readText() }
+            name = Path.of(pathString).toFile().nameWithoutExtension
+        }
+    }
+
+    /**
+     * SourceCode for internally generated nodes (usually Modules)
+     */
+    class Generated(override val name: String) : SourceCode() {
+        override val isFromResources: Boolean = false
+        override val isFromFilesystem: Boolean = false
+        override val origin: String = name
+        override val text: String = "<generated code node, no text representation>"
+    }
+}

codeCore/src/prog8/code/core/Zeropage.kt

@@ -0,0 +1,122 @@
+package prog8.code.core
+
+import com.github.michaelbull.result.Err
+import com.github.michaelbull.result.Ok
+import com.github.michaelbull.result.Result
+
+
+class ZeropageAllocationError(message: String) : Exception(message)
+
+
+abstract class Zeropage(protected val options: CompilationOptions) {
+
+    abstract val SCRATCH_B1 : UInt      // temp storage for a single byte
+    abstract val SCRATCH_REG : UInt     // temp storage for a register, must be B1+1
+    abstract val SCRATCH_W1 : UInt      // temp storage 1 for a word  $fb+$fc
+    abstract val SCRATCH_W2 : UInt      // temp storage 2 for a word  $fb+$fc
+
+    data class ZpAllocation(val address: UInt, val dt: DataType, val size: Int)
+
+    // the variables allocated into Zeropage.
+    // name (scoped) ==> pair of address to (Datatype + bytesize)
+    val allocatedVariables = mutableMapOf<List<String>, ZpAllocation>()
+
+    val free = mutableListOf<UInt>()     // subclasses must set this to the appropriate free locations.
+
+    fun removeReservedFromFreePool() {
+        synchronized(this) {
+            for (reserved in options.zpReserved)
+                reserve(reserved)
+
+            free.removeAll(setOf(SCRATCH_B1, SCRATCH_REG, SCRATCH_W1, SCRATCH_W1 + 1u, SCRATCH_W2, SCRATCH_W2 + 1u))
+        }
+    }
+
+    fun availableBytes() = if(options.zeropage== ZeropageType.DONTUSE) 0 else free.size
+    fun hasByteAvailable() = if(options.zeropage== ZeropageType.DONTUSE) false else free.isNotEmpty()
+    fun hasWordAvailable(): Boolean {
+        if(options.zeropage== ZeropageType.DONTUSE)
+            return false
+
+        return free.windowed(2).any { it[0] == it[1] - 1u }
+    }
+
+    fun allocate(name: List<String>,
+                 datatype: DataType,
+                 numElements: Int?,
+                 position: Position?,
+                 errors: IErrorReporter
+    ): Result<Pair<UInt, Int>, ZeropageAllocationError> {
+
+        require(name.isEmpty() || name !in allocatedVariables) {"name can't be allocated twice"}
+
+        if(options.zeropage== ZeropageType.DONTUSE)
+            return Err(ZeropageAllocationError("zero page usage has been disabled"))
+
+        val size: Int =
+                when (datatype) {
+                    in IntegerDatatypes -> options.compTarget.memorySize(datatype)
+                    DataType.STR, in ArrayDatatypes  -> {
+                        val memsize = options.compTarget.memorySize(datatype, numElements!!)
+                        if(position!=null)
+                            errors.warn("allocating a large value in zeropage; str/array $memsize bytes", position)
+                        else
+                            errors.warn("$name: allocating a large value in zeropage; str/array $memsize bytes", Position.DUMMY)
+                        memsize
+                    }
+                    DataType.FLOAT -> {
+                        if (options.floats) {
+                            val memsize = options.compTarget.memorySize(DataType.FLOAT)
+                            if(position!=null)
+                                errors.warn("allocating a large value in zeropage; float $memsize bytes", position)
+                            else
+                                errors.warn("$name: allocating a large value in zeropage; float $memsize bytes", Position.DUMMY)
+                            memsize
+                        } else return Err(ZeropageAllocationError("floating point option not enabled"))
+                    }
+                    else -> return Err(ZeropageAllocationError("cannot put datatype $datatype in zeropage"))
+                }
+
+        synchronized(this) {
+            if(free.size > 0) {
+                if(size==1) {
+                    for(candidate in free.minOrNull()!! .. free.maxOrNull()!!+1u) {
+                        if(oneSeparateByteFree(candidate))
+                            return Ok(Pair(makeAllocation(candidate, 1, datatype, name), 1))
+                    }
+                    return Ok(Pair(makeAllocation(free[0], 1, datatype, name), 1))
+                }
+                for(candidate in free.minOrNull()!! .. free.maxOrNull()!!+1u) {
+                    if (sequentialFree(candidate, size))
+                        return Ok(Pair(makeAllocation(candidate, size, datatype, name), size))
+                }
+            }
+        }
+
+        return Err(ZeropageAllocationError("no more free space in ZP to allocate $size sequential bytes"))
+    }
+
+    private fun reserve(range: UIntRange) = free.removeAll(range)
+
+    private fun makeAllocation(address: UInt, size: Int, datatype: DataType, name: List<String>): UInt {
+        require(size>=0)
+        free.removeAll(address until address+size.toUInt())
+        if(name.isNotEmpty()) {
+            allocatedVariables[name] = when(datatype) {
+                in NumericDatatypes -> ZpAllocation(address, datatype, size)        // numerical variables in zeropage never have an initial value here because they are set in separate initializer assignments
+                DataType.STR -> ZpAllocation(address, datatype, size)
+                in ArrayDatatypes -> ZpAllocation(address, datatype, size)
+                else -> throw AssemblyError("invalid dt")
+            }
+        }
+        return address
+    }
+
+    private fun oneSeparateByteFree(address: UInt) = address in free && address-1u !in free && address+1u !in free
+    private fun sequentialFree(address: UInt, size: Int): Boolean {
+        require(size>0)
+        return free.containsAll((address until address+size.toUInt()).toList())
+    }
+
+    abstract fun allocateCx16VirtualRegisters()
+}

codeCore/src/prog8/code/target/AtariTarget.kt

@@ -0,0 +1,28 @@
+package prog8.code.target
+
+import prog8.code.core.*
+import prog8.code.target.atari.AtariMachineDefinition
+
+
+class AtariTarget: ICompilationTarget, IStringEncoding by Encoder, IMemSizer {
+    override val name = NAME
+    override val machine = AtariMachineDefinition()
+    override val supportedEncodings = setOf(Encoding.ATASCII)
+    override val defaultEncoding = Encoding.ATASCII
+
+    companion object {
+        const val NAME = "atari"
+    }
+
+    override fun memorySize(dt: DataType): Int {
+        return when(dt) {
+            in ByteDatatypes -> 1
+            in WordDatatypes, in PassByReferenceDatatypes -> 2
+            DataType.FLOAT -> machine.FLOAT_MEM_SIZE
+            else -> Int.MIN_VALUE
+        }
+    }
+
+    override fun memorySize(arrayDt: DataType, numElements: Int) =
+        memorySize(ArrayToElementTypes.getValue(arrayDt)) * numElements
+}

codeCore/src/prog8/code/target/C128Target.kt

@@ -0,0 +1,20 @@
+package prog8.code.target
+
+import prog8.code.core.Encoding
+import prog8.code.core.ICompilationTarget
+import prog8.code.core.IMemSizer
+import prog8.code.core.IStringEncoding
+import prog8.code.target.c128.C128MachineDefinition
+import prog8.code.target.cbm.CbmMemorySizer
+
+
+class C128Target: ICompilationTarget, IStringEncoding by Encoder, IMemSizer by CbmMemorySizer {
+    override val name = NAME
+    override val machine = C128MachineDefinition()
+    override val supportedEncodings = setOf(Encoding.PETSCII, Encoding.SCREENCODES)
+    override val defaultEncoding = Encoding.PETSCII
+
+    companion object {
+        const val NAME = "c128"
+    }
+}

codeCore/src/prog8/code/target/C64Target.kt

@@ -0,0 +1,20 @@
+package prog8.code.target
+
+import prog8.code.core.Encoding
+import prog8.code.core.ICompilationTarget
+import prog8.code.core.IMemSizer
+import prog8.code.core.IStringEncoding
+import prog8.code.target.c64.C64MachineDefinition
+import prog8.code.target.cbm.CbmMemorySizer
+
+
+class C64Target: ICompilationTarget, IStringEncoding by Encoder, IMemSizer by CbmMemorySizer {
+    override val name = NAME
+    override val machine = C64MachineDefinition()
+    override val supportedEncodings = setOf(Encoding.PETSCII, Encoding.SCREENCODES)
+    override val defaultEncoding = Encoding.PETSCII
+
+    companion object {
+        const val NAME = "c64"
+    }
+}

codeCore/src/prog8/code/target/Cx16Target.kt

@@ -0,0 +1,20 @@
+package prog8.code.target
+
+import prog8.code.core.Encoding
+import prog8.code.core.ICompilationTarget
+import prog8.code.core.IMemSizer
+import prog8.code.core.IStringEncoding
+import prog8.code.target.cbm.CbmMemorySizer
+import prog8.code.target.cx16.CX16MachineDefinition
+
+
+class Cx16Target: ICompilationTarget, IStringEncoding by Encoder, IMemSizer by CbmMemorySizer {
+    override val name = NAME
+    override val machine = CX16MachineDefinition()
+    override val supportedEncodings = setOf(Encoding.PETSCII, Encoding.SCREENCODES, Encoding.ISO)
+    override val defaultEncoding = Encoding.PETSCII
+
+    companion object {
+        const val NAME = "cx16"
+    }
+}

codeCore/src/prog8/code/target/Encoder.kt

@@ -0,0 +1,39 @@
+package prog8.code.target
+
+import com.github.michaelbull.result.fold
+import prog8.code.core.Encoding
+import prog8.code.core.IStringEncoding
+import prog8.code.core.InternalCompilerException
+import prog8.code.target.cbm.AtasciiEncoding
+import prog8.code.target.cbm.IsoEncoding
+import prog8.code.target.cbm.PetsciiEncoding
+
+
+object Encoder: IStringEncoding {
+    override fun encodeString(str: String, encoding: Encoding): List<UByte> {
+        val coded = when(encoding) {
+            Encoding.PETSCII -> PetsciiEncoding.encodePetscii(str, true)
+            Encoding.SCREENCODES -> PetsciiEncoding.encodeScreencode(str, true)
+            Encoding.ISO -> IsoEncoding.encode(str)
+            Encoding.ATASCII -> AtasciiEncoding.encode(str)
+            else -> throw InternalCompilerException("unsupported encoding $encoding")
+        }
+        return coded.fold(
+            failure = { throw it },
+            success = { it }
+        )
+    }
+    override fun decodeString(bytes: List<UByte>, encoding: Encoding): String {
+        val decoded = when(encoding) {
+            Encoding.PETSCII -> PetsciiEncoding.decodePetscii(bytes, true)
+            Encoding.SCREENCODES -> PetsciiEncoding.decodeScreencode(bytes, true)
+            Encoding.ISO -> IsoEncoding.decode(bytes)
+            Encoding.ATASCII -> AtasciiEncoding.decode(bytes)
+            else -> throw InternalCompilerException("unsupported encoding $encoding")
+        }
+        return decoded.fold(
+            failure = { throw it },
+            success = { it }
+        )
+    }
+}

codeCore/src/prog8/code/target/VMTarget.kt

@@ -0,0 +1,27 @@
+package prog8.code.target
+
+import prog8.code.core.*
+import prog8.code.target.virtual.VirtualMachineDefinition
+
+class VMTarget: ICompilationTarget, IStringEncoding by Encoder, IMemSizer {
+    override val name = NAME
+    override val machine = VirtualMachineDefinition()
+    override val supportedEncodings = setOf(Encoding.ISO)
+    override val defaultEncoding = Encoding.ISO
+
+    companion object {
+        const val NAME = "virtual"
+    }
+
+    override fun memorySize(dt: DataType): Int {
+        return when(dt) {
+            in ByteDatatypes -> 1
+            in WordDatatypes, in PassByReferenceDatatypes -> 2
+            DataType.FLOAT -> machine.FLOAT_MEM_SIZE
+            else -> Int.MIN_VALUE
+        }
+    }
+
+    override fun memorySize(arrayDt: DataType, numElements: Int) =
+        memorySize(ArrayToElementTypes.getValue(arrayDt)) * numElements
+}

codeCore/src/prog8/code/target/atari/AtariMachineDefinition.kt

@@ -0,0 +1,65 @@
+package prog8.code.target.atari
+
+import prog8.code.core.*
+import prog8.code.target.c64.normal6502instructions
+import java.nio.file.Path
+
+
+class AtariMachineDefinition: IMachineDefinition {
+
+    override val cpu = CpuType.CPU6502
+
+    override val FLOAT_MAX_POSITIVE = 9.999999999e97
+    override val FLOAT_MAX_NEGATIVE = -9.999999999e97
+    override val FLOAT_MEM_SIZE = 6
+    override val PROGRAM_LOAD_ADDRESS = 0x2000u
+
+    // the 2*256 byte evaluation stack (on which bytes, words, and even floats are stored during calculations)
+    override var ESTACK_LO = 0x1a00u     //  $1a00-$1aff inclusive      // TODO
+    override var ESTACK_HI = 0x1b00u     //  $1b00-$1bff inclusive      // TODO
+
+    override lateinit var zeropage: Zeropage
+
+    override fun getFloatAsmBytes(num: Number) = TODO("float asm bytes from number")
+
+    override fun importLibs(compilerOptions: CompilationOptions, compilationTargetName: String): List<String> {
+        return if (compilerOptions.output == OutputType.XEX)
+            listOf("syslib")
+        else
+            emptyList()
+    }
+
+    override fun launchEmulator(selectedEmulator: Int, programNameWithPath: Path) {
+        val emulatorName: String
+        val cmdline: List<String>
+        when(selectedEmulator) {
+            1 -> {
+                emulatorName = "atari800"
+                cmdline = listOf(emulatorName, "-xl", "-xl-rev", "2", "-nobasic", "-run", "${programNameWithPath}.xex")
+            }
+            2 -> {
+                emulatorName = "altirra"
+                cmdline = listOf("Altirra64.exe", "${programNameWithPath.normalize()}.xex")
+            }
+            else -> {
+                System.err.println("Atari target only supports atari800 and altirra emulators.")
+                return
+            }
+        }
+
+        // TODO monlist?
+
+        println("\nStarting Atari800XL emulator $emulatorName...")
+        val processb = ProcessBuilder(cmdline).inheritIO()
+        val process: Process = processb.start()
+        process.waitFor()
+    }
+
+    override fun isIOAddress(address: UInt): Boolean = address==0u || address==1u || address in 0xd000u..0xdfffu        // TODO
+
+    override fun initializeZeropage(compilerOptions: CompilationOptions) {
+        zeropage = AtariZeropage(compilerOptions)
+    }
+
+    override val opcodeNames = normal6502instructions
+}

codeCore/src/prog8/code/target/atari/AtariZeropage.kt

@@ -0,0 +1,52 @@
+package prog8.code.target.atari
+
+import prog8.code.core.CompilationOptions
+import prog8.code.core.InternalCompilerException
+import prog8.code.core.Zeropage
+import prog8.code.core.ZeropageType
+
+class AtariZeropage(options: CompilationOptions) : Zeropage(options) {
+
+    override val SCRATCH_B1 = 0xcbu      // temp storage for a single byte
+    override val SCRATCH_REG = 0xccu     // temp storage for a register, must be B1+1
+    override val SCRATCH_W1 = 0xcdu      // temp storage 1 for a word  $cd+$ce
+    override val SCRATCH_W2 = 0xcfu      // temp storage 2 for a word  $cf+$d0        TODO is $d0 okay to use?
+
+    init {
+        if (options.floats && options.zeropage !in arrayOf(
+                ZeropageType.FLOATSAFE,
+                ZeropageType.BASICSAFE,
+                ZeropageType.DONTUSE
+            ))
+            throw InternalCompilerException("when floats are enabled, zero page type should be 'floatsafe' or 'basicsafe' or 'dontuse'")
+
+        when (options.zeropage) {
+            ZeropageType.FULL -> {
+                // TODO all atari usable zero page locations, except the ones used by the system's IRQ routine
+                free.addAll(0x00u..0xffu)
+                // TODO atari  free.removeAll(setOf(0xa0u, 0xa1u, 0xa2u, 0x91u, 0xc0u, 0xc5u, 0xcbu, 0xf5u, 0xf6u))        // these are updated by IRQ
+            }
+            ZeropageType.KERNALSAFE -> {
+                free.addAll(0x80u..0xffu)       // TODO
+            }
+            ZeropageType.BASICSAFE,
+            ZeropageType.FLOATSAFE -> {
+                free.addAll(0x80u..0xffu)       // TODO
+                free.removeAll(0xd4u .. 0xefu)      // floating point storage
+            }
+            ZeropageType.DONTUSE -> {
+                free.clear()  // don't use zeropage at all
+            }
+        }
+
+        val distictFree = free.distinct()
+        free.clear()
+        free.addAll(distictFree)
+
+        removeReservedFromFreePool()
+    }
+
+    override fun allocateCx16VirtualRegisters() {
+        TODO("Not known if atari can put the virtual regs in ZP")
+    }
+}

codeCore/src/prog8/code/target/c128/C128MachineDefinition.kt

@@ -0,0 +1,55 @@
+package prog8.code.target.c128
+
+import prog8.code.core.*
+import prog8.code.target.c64.normal6502instructions
+import prog8.code.target.cbm.Mflpt5
+import java.nio.file.Path
+
+
+class C128MachineDefinition: IMachineDefinition {
+
+    override val cpu = CpuType.CPU6502
+
+    override val FLOAT_MAX_POSITIVE = Mflpt5.FLOAT_MAX_POSITIVE
+    override val FLOAT_MAX_NEGATIVE = Mflpt5.FLOAT_MAX_NEGATIVE
+    override val FLOAT_MEM_SIZE = Mflpt5.FLOAT_MEM_SIZE
+    override val PROGRAM_LOAD_ADDRESS = 0x1c01u
+
+    // the 2*256 byte evaluation stack (on which bytes, words, and even floats are stored during calculations)
+    override var ESTACK_LO = 0x1a00u     //  $1a00-$1aff inclusive
+    override var ESTACK_HI = 0x1b00u     //  $1b00-$1bff inclusive
+
+    override lateinit var zeropage: Zeropage
+
+    override fun getFloatAsmBytes(num: Number) = Mflpt5.fromNumber(num).makeFloatFillAsm()
+
+    override fun importLibs(compilerOptions: CompilationOptions, compilationTargetName: String): List<String> {
+        return if (compilerOptions.launcher == CbmPrgLauncherType.BASIC || compilerOptions.output == OutputType.PRG)
+            listOf("syslib")
+        else
+            emptyList()
+    }
+
+    override fun launchEmulator(selectedEmulator: Int, programNameWithPath: Path) {
+        if(selectedEmulator!=1) {
+            System.err.println("The c128 target only supports the main emulator (Vice).")
+            return
+        }
+
+        println("\nStarting C-128 emulator x128...")
+        val viceMonlist = viceMonListName(programNameWithPath.toString())
+        val cmdline = listOf("x128", "-silent", "-moncommands", viceMonlist,
+                "-autostartprgmode", "1", "-autostart-warp", "-autostart", "${programNameWithPath}.prg")
+        val processb = ProcessBuilder(cmdline).inheritIO()
+        val process: Process = processb.start()
+        process.waitFor()
+    }
+
+    override fun isIOAddress(address: UInt): Boolean = address==0u || address==1u || address in 0xd000u..0xdfffu
+
+    override fun initializeZeropage(compilerOptions: CompilationOptions) {
+        zeropage = C128Zeropage(compilerOptions)
+    }
+
+    override val opcodeNames = normal6502instructions
+}

codeCore/src/prog8/code/target/c128/C128Zeropage.kt

@@ -0,0 +1,51 @@
+package prog8.code.target.c128
+
+import prog8.code.core.CompilationOptions
+import prog8.code.core.InternalCompilerException
+import prog8.code.core.Zeropage
+import prog8.code.core.ZeropageType
+
+
+class C128Zeropage(options: CompilationOptions) : Zeropage(options) {
+
+    override val SCRATCH_B1 = 0x9bu      // temp storage for a single byte
+    override val SCRATCH_REG = 0x9cu     // temp storage for a register, must be B1+1
+    override val SCRATCH_W1 = 0xfbu      // temp storage 1 for a word  $fb+$fc
+    override val SCRATCH_W2 = 0xfdu      // temp storage 2 for a word  $fd+$fe
+
+
+    init {
+        if (options.floats && options.zeropage !in arrayOf(
+                ZeropageType.FLOATSAFE,
+                ZeropageType.BASICSAFE,
+                ZeropageType.DONTUSE
+            ))
+            throw InternalCompilerException("when floats are enabled, zero page type should be 'floatsafe' or 'basicsafe' or 'dontuse'")
+
+        when (options.zeropage) {
+            ZeropageType.FULL -> {
+                // TODO all c128 usable zero page locations, except the ones used by the system's IRQ routine
+                free.addAll(0x0au..0xffu)       // TODO c128 what about $02-$09?
+                // TODO c128  free.removeAll(setOf(0xa0u, 0xa1u, 0xa2u, 0x91u, 0xc0u, 0xc5u, 0xcbu, 0xf5u, 0xf6u))        // these are updated by IRQ
+            }
+            ZeropageType.KERNALSAFE,
+            ZeropageType.FLOATSAFE,
+            ZeropageType.BASICSAFE -> {
+                free.clear()   // TODO c128 usable zero page addresses
+            }
+            ZeropageType.DONTUSE -> {
+                free.clear()  // don't use zeropage at all
+            }
+        }
+
+        val distictFree = free.distinct()
+        free.clear()
+        free.addAll(distictFree)
+
+        removeReservedFromFreePool()
+    }
+
+    override fun allocateCx16VirtualRegisters() {
+        TODO("Not known if C128 can put the virtual regs in ZP")
+    }
+}

codeCore/src/prog8/code/target/c64/C64MachineDefinition.kt

@@ -0,0 +1,76 @@
+package prog8.code.target.c64
+
+import prog8.code.core.*
+import prog8.code.target.cbm.Mflpt5
+import java.io.IOException
+import java.nio.file.Path
+
+
+class C64MachineDefinition: IMachineDefinition {
+
+    override val cpu = CpuType.CPU6502
+
+    override val FLOAT_MAX_POSITIVE = Mflpt5.FLOAT_MAX_POSITIVE
+    override val FLOAT_MAX_NEGATIVE = Mflpt5.FLOAT_MAX_NEGATIVE
+    override val FLOAT_MEM_SIZE = Mflpt5.FLOAT_MEM_SIZE
+    override val PROGRAM_LOAD_ADDRESS = 0x0801u
+
+    // the 2*256 byte evaluation stack (on which bytes, words, and even floats are stored during calculations)
+    override var ESTACK_LO = 0xce00u     //  $ce00-$ceff inclusive
+    override var ESTACK_HI = 0xcf00u     //  $ce00-$ceff inclusive
+
+    override lateinit var zeropage: Zeropage
+
+    override fun getFloatAsmBytes(num: Number) = Mflpt5.fromNumber(num).makeFloatFillAsm()
+
+    override fun importLibs(compilerOptions: CompilationOptions, compilationTargetName: String): List<String> {
+        return if (compilerOptions.launcher == CbmPrgLauncherType.BASIC || compilerOptions.output == OutputType.PRG)
+            listOf("syslib")
+        else
+            emptyList()
+    }
+
+    override fun launchEmulator(selectedEmulator: Int, programNameWithPath: Path) {
+        if(selectedEmulator!=1) {
+            System.err.println("The c64 target only supports the main emulator (Vice).")
+            return
+        }
+
+        for(emulator in listOf("x64sc", "x64")) {
+            println("\nStarting C-64 emulator $emulator...")
+            val viceMonlist = viceMonListName(programNameWithPath.toString())
+            val cmdline = listOf(emulator, "-silent", "-moncommands", viceMonlist,
+                    "-autostartprgmode", "1", "-autostart-warp", "-autostart", "${programNameWithPath}.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 isIOAddress(address: UInt): Boolean = address==0u || address==1u || address in 0xd000u..0xdfffu
+
+    override fun initializeZeropage(compilerOptions: CompilationOptions) {
+        zeropage = C64Zeropage(compilerOptions)
+    }
+
+    override val opcodeNames = normal6502instructions
+}
+
+
+// 6502 opcodes (including aliases and illegal opcodes), these cannot be used as variable or label names
+internal val normal6502instructions = 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")

codeCore/src/prog8/code/target/c64/C64Zeropage.kt

@@ -0,0 +1,96 @@
+package prog8.code.target.c64
+
+import prog8.code.core.*
+
+
+class C64Zeropage(options: CompilationOptions) : Zeropage(options) {
+
+    override val SCRATCH_B1 = 0x02u      // temp storage for a single byte
+    override val SCRATCH_REG = 0x03u     // temp storage for a register, must be B1+1
+    override val SCRATCH_W1 = 0xfbu      // temp storage 1 for a word  $fb+$fc
+    override val SCRATCH_W2 = 0xfdu      // temp storage 2 for a word  $fd+$fe
+
+
+    init {
+        if (options.floats && options.zeropage !in arrayOf(
+                ZeropageType.FLOATSAFE,
+                ZeropageType.BASICSAFE,
+                ZeropageType.DONTUSE
+            ))
+            throw InternalCompilerException("when floats are enabled, zero page type should be 'floatsafe' or 'basicsafe' or 'dontuse'")
+
+        if (options.zeropage == ZeropageType.FULL) {
+            free.addAll(0x02u..0xffu)
+            free.removeAll(setOf(SCRATCH_B1, SCRATCH_REG, SCRATCH_W1, SCRATCH_W1+1u, SCRATCH_W2, SCRATCH_W2+1u))
+            free.removeAll(setOf(0xa0u, 0xa1u, 0xa2u, 0x91u, 0xc0u, 0xc5u, 0xcbu, 0xf5u, 0xf6u))        // these are updated by IRQ
+        } else {
+            if (options.zeropage == ZeropageType.KERNALSAFE || options.zeropage == ZeropageType.FLOATSAFE) {
+                free.addAll(listOf(
+                        0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
+                        0x10, 0x11, 0x12, 0x13, 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 'kernal work storage area'
+                ).map{it.toUInt()})
+            }
+
+            if (options.zeropage == ZeropageType.FLOATSAFE) {
+                // remove the zeropage locations used for floating point operations from the free list
+                free.removeAll(listOf(
+                        0x03, 0x04, 0x10, 0x11, 0x12,
+                        0x22, 0x23, 0x24, 0x25, 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, 0xff
+                ).map{it.toUInt()})
+            }
+
+            if(options.zeropage!= ZeropageType.DONTUSE) {
+                // add the free Zp addresses
+                // these are valid for the C-64 but allow BASIC to keep running fully *as long as you don't use tape I/O*
+                free.addAll(listOf(0x02, 0x03, 0x04, 0x05, 0x06, 0x0a, 0x0e,
+                        0x92, 0x96, 0x9b, 0x9c, 0x9e, 0x9f, 0xa5, 0xa6,
+                        0xb0, 0xb1, 0xbe, 0xbf, 0xf9).map{it.toUInt()})
+            } else {
+                // don't use the zeropage at all
+                free.clear()
+            }
+        }
+
+        val distictFree = free.distinct()
+        free.clear()
+        free.addAll(distictFree)
+
+        removeReservedFromFreePool()
+
+        if(options.zeropage==ZeropageType.FULL || options.zeropage==ZeropageType.KERNALSAFE) {
+            // in these cases there is enough space on the zero page to stick the cx16 virtual registers in there as well.
+            allocateCx16VirtualRegisters()
+        }
+    }
+
+    override fun allocateCx16VirtualRegisters() {
+        // Note: the 16 virtual registers R0-R15 are not regular allocated variables, they're *memory mapped* elsewhere to fixed addresses.
+        // However, to be able for the compiler to "see" them as zero page variables, we have to register them here as well.
+        // This is important because the compiler sometimes treats ZP variables more efficiently (for example if it's a pointer)
+        // The base addres is $04.  Unfortunately it cannot be the same as on the Commander X16 ($02).
+        for(reg in 0..15) {
+            allocatedVariables[listOf("cx16", "r${reg}")]   = ZpAllocation((4+reg*2).toUInt(), DataType.UWORD, 2)       // cx16.r0 .. cx16.r15
+            allocatedVariables[listOf("cx16", "r${reg}s")]  = ZpAllocation((4+reg*2).toUInt(), DataType.WORD, 2)        // cx16.r0s .. cx16.r15s
+            allocatedVariables[listOf("cx16", "r${reg}L")]  = ZpAllocation((4+reg*2).toUInt(), DataType.UBYTE, 1)       // cx16.r0L .. cx16.r15L
+            allocatedVariables[listOf("cx16", "r${reg}H")]  = ZpAllocation((5+reg*2).toUInt(), DataType.UBYTE, 1)       // cx16.r0H .. cx16.r15H
+            allocatedVariables[listOf("cx16", "r${reg}sL")] = ZpAllocation((4+reg*2).toUInt(), DataType.BYTE, 1)        // cx16.r0sL .. cx16.r15sL
+            allocatedVariables[listOf("cx16", "r${reg}sH")] = ZpAllocation((5+reg*2).toUInt(), DataType.BYTE, 1)        // cx16.r0sH .. cx16.r15sH
+            free.remove((4+reg*2).toUInt())
+            free.remove((5+reg*2).toUInt())
+        }
+    }
+}

codeCore/src/prog8/code/target/cbm/AtasciiEncoding.kt

@@ -0,0 +1,214 @@
+package prog8.code.target.cbm
+
+import com.github.michaelbull.result.Ok
+import com.github.michaelbull.result.Result
+import java.io.CharConversionException
+
+object AtasciiEncoding {
+
+    private val decodeTable: CharArray = charArrayOf(
+        // $00
+        '♥',
+        '├',
+        '\uf130',    //  🮇    0x02 -> RIGHT ONE QUARTER BLOCK (CUS)
+        '┘',
+        '┤',
+        '┐',
+        '╱',
+        '╲',
+        '◢',
+        '▗',
+        '◣',
+        '▝',
+        '▘',
+        '\uf132',    //  🮂    0x1d -> UPPER ONE QUARTER BLOCK (CUS)
+        '▂',
+        '▖',
+
+        // $10
+     	'♣',
+        '┌',
+        '─',
+        '┼',
+        '•',
+        '▄',
+        '▎',
+        '┬',
+        '┴',
+        '▌',
+        '└',
+        '\u001b',           // $1b = escape
+        '\ufffe',           // UNDEFINED CHAR.   $1c = cursor up
+        '\ufffe',           // UNDEFINED CHAR.   $1d = cursor down
+        '\ufffe',           // UNDEFINED CHAR.   $1e = cursor left
+        '\ufffe',           // UNDEFINED CHAR.   $1f = cursor right
+
+        // $20
+        ' ',
+        '!',
+        '"',
+        '#',
+        '$',
+        '%',
+        '&',
+        '\'',
+        '(',
+        ')',
+        '*',
+        '+',
+        ',',
+        '-',
+        '.',
+        '/',
+
+        // $30
+     	'0',
+        '1',
+        '2',
+        '3',
+        '4',
+        '5',
+        '6',
+        '7',
+        '8',
+        '9',
+        ':',
+        ';',
+        '<',
+        '=',
+        '>',
+        '?',
+
+        // $40
+     	'@',
+        'A',
+        'B',
+        'C',
+        'D',
+        'E',
+        'F',
+        'G',
+        'H',
+        'I',
+        'J',
+        'K',
+        'L',
+        'M',
+        'N',
+        'O',
+
+        // $50
+        'P',
+        'Q',
+        'R',
+        'S',
+        'T',
+        'U',
+        'V',
+        'W',
+        'X',
+        'Y',
+        'Z',
+        '[',
+        '\\',
+        ']',
+        '^',
+        '_',
+
+        // $60
+        '♦',
+        'a',
+        'b',
+        'c',
+        'd',
+        'e',
+        'f',
+        'g',
+        'h',
+        'i',
+        'j',
+        'k',
+        'l',
+        'm',
+        'n',
+        'o',
+
+        // $70
+        'p',
+        'q',
+        'r',
+        's',
+        't',
+        'u',
+        'v',
+        'w',
+        'x',
+        'y',
+        'z',
+        '♠',
+        '|',
+        '\u000c',    //       $7d -> FORM FEED (CLEAR SCREEN)
+        '\u0008',    //       $7e -> BACKSPACE
+        '\u0009',    //       $7f -> TAB
+
+        // $80-$ff are reversed video characters + various special characters.
+        '\ufffe', '\ufffe', '\ufffe', '\ufffe', '\ufffe', '\ufffe', '\ufffe', '\ufffe',
+        '\ufffe', '\ufffe', '\ufffe', '\ufffe', '\ufffe', '\ufffe', '\ufffe', '\ufffe',
+        // $90
+        '\ufffe', '\ufffe', '\ufffe', '\ufffe', '\ufffe', '\ufffe', '\ufffe', '\ufffe',
+        '\ufffe',
+        '\ufffe',
+        '\ufffe',
+        '\n',               // $9b -> EOL/RETURN
+        '\ufffe',           // UNDEFINED   $9c = DELETE LINE
+        '\ufffe',           // UNDEFINED   $9d = INSERT LINE
+        '\ufffe',           // UNDEFINED   $9e = CLEAR TAB STOP
+        '\ufffe',           // UNDEFINED   $9f = SET TAB STOP
+        // $a0
+        '\ufffe', '\ufffe', '\ufffe', '\ufffe', '\ufffe', '\ufffe', '\ufffe', '\ufffe',
+        '\ufffe', '\ufffe', '\ufffe', '\ufffe', '\ufffe', '\ufffe', '\ufffe', '\ufffe',
+        // $b0
+        '\ufffe', '\ufffe', '\ufffe', '\ufffe', '\ufffe', '\ufffe', '\ufffe', '\ufffe',
+        '\ufffe', '\ufffe', '\ufffe', '\ufffe', '\ufffe', '\ufffe', '\ufffe', '\ufffe',
+        // $c0
+        '\ufffe', '\ufffe', '\ufffe', '\ufffe', '\ufffe', '\ufffe', '\ufffe', '\ufffe',
+        '\ufffe', '\ufffe', '\ufffe', '\ufffe', '\ufffe', '\ufffe', '\ufffe', '\ufffe',
+        // $d0
+        '\ufffe', '\ufffe', '\ufffe', '\ufffe', '\ufffe', '\ufffe', '\ufffe', '\ufffe',
+        '\ufffe', '\ufffe', '\ufffe', '\ufffe', '\ufffe', '\ufffe', '\ufffe', '\ufffe',
+        // $e0
+        '\ufffe', '\ufffe', '\ufffe', '\ufffe', '\ufffe', '\ufffe', '\ufffe', '\ufffe',
+        '\ufffe', '\ufffe', '\ufffe', '\ufffe', '\ufffe', '\ufffe', '\ufffe', '\ufffe',
+        // $f0
+        '\ufffe', '\ufffe', '\ufffe', '\ufffe', '\ufffe', '\ufffe', '\ufffe', '\ufffe',
+        '\ufffe',
+        '\ufffe',
+        '\ufffe',
+        '\ufffe',
+        '\ufffe',
+        '\u0007',           // $fd = bell/beep
+        '\u007f',           // $fe = DELETE
+        '\ufffe'            // UNDEFINED     $ff = INSERT
+    )
+
+    private val encodeTable = decodeTable.withIndex().associate{it.value to it.index}
+
+
+    fun encode(str: String): Result<List<UByte>, CharConversionException> {
+        val mapped = str.map { chr ->
+            when (chr) {
+                '\u0000' -> 0u
+                in '\u8000'..'\u80ff' -> {
+                    // special case: take the lower 8 bit hex value directly
+                    (chr.code - 0x8000).toUByte()
+                }
+                else -> encodeTable.getValue(chr).toUByte()
+            }
+        }
+        return Ok(mapped)
+    }
+
+    fun decode(bytes: List<UByte>): Result<String, CharConversionException> {
+        return Ok(bytes.map { decodeTable[it.toInt()] }.joinToString(""))
+    }
+}

codeCore/src/prog8/code/target/cbm/CbmMemorySizer.kt

@@ -0,0 +1,18 @@
+package prog8.code.target.cbm
+
+import prog8.code.core.*
+
+
+internal object CbmMemorySizer: IMemSizer {
+    override fun memorySize(dt: DataType): Int {
+        return when(dt) {
+            in ByteDatatypes -> 1
+            in WordDatatypes, in PassByReferenceDatatypes -> 2
+            DataType.FLOAT -> Mflpt5.FLOAT_MEM_SIZE
+            else -> Int.MIN_VALUE
+        }
+    }
+
+    override fun memorySize(arrayDt: DataType, numElements: Int) =
+        memorySize(ArrayToElementTypes.getValue(arrayDt)) * numElements
+}

codeCore/src/prog8/code/target/cbm/IsoEncoding.kt

@@ -0,0 +1,37 @@
+package prog8.code.target.cbm
+
+import com.github.michaelbull.result.Err
+import com.github.michaelbull.result.Ok
+import com.github.michaelbull.result.Result
+import java.io.CharConversionException
+import java.nio.charset.Charset
+
+object IsoEncoding {
+    val charset: Charset = Charset.forName("ISO-8859-15")
+
+    fun encode(str: String): Result<List<UByte>, CharConversionException> {
+        return try {
+            val mapped = str.map { chr ->
+                when (chr) {
+                    '\u0000' -> 0u
+                    in '\u8000'..'\u80ff' -> {
+                        // special case: take the lower 8 bit hex value directly
+                        (chr.code - 0x8000).toUByte()
+                    }
+                    else -> charset.encode(chr.toString())[0].toUByte()
+                }
+            }
+            Ok(mapped)
+        } catch (ce: CharConversionException) {
+            Err(ce)
+        }
+    }
+
+    fun decode(bytes: List<UByte>): Result<String, CharConversionException> {
+        return try {
+            Ok(String(bytes.map { it.toByte() }.toByteArray(), charset))
+        } catch (ce: CharConversionException) {
+            Err(ce)
+        }
+    }
+}

codeCore/src/prog8/code/target/cbm/Mflpt5.kt

@@ -0,0 +1,77 @@
+package prog8.code.target.cbm
+
+import prog8.code.core.InternalCompilerException
+import kotlin.math.absoluteValue
+import kotlin.math.pow
+
+
+data class Mflpt5(val b0: UByte, val b1: UByte, val b2: UByte, val b3: UByte, val b4: UByte) {
+
+    companion object {
+        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 FLOAT_MEM_SIZE = 5
+
+        val zero = Mflpt5(0u, 0u, 0u, 0u, 0u)
+        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 InternalCompilerException("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 InternalCompilerException("floating point overflow: $this")
+                exponent == 0 -> zero
+                else -> {
+                    val mantLong = mantissa.toLong()
+                    Mflpt5(
+                        exponent.toUByte(),
+                        (mantLong.and(0x7f000000L) ushr 24).or(sign).toUByte(),
+                        (mantLong.and(0x00ff0000L) ushr 16).toUByte(),
+                        (mantLong.and(0x0000ff00L) ushr 8).toUByte(),
+                        (mantLong.and(0x000000ffL)).toUByte()
+                    )
+                }
+            }
+        }
+    }
+
+    fun toDouble(): Double {
+        if (this == zero) return 0.0
+        val exp = b0.toInt() - 128
+        val sign = (b1.toInt() and 0x80) > 0
+        val number = 0x80000000L.or(b1.toLong() shl 24).or(b2.toLong() shl 16).or(b3.toLong() shl 8).or(b4.toLong())
+        val result = number.toDouble() * (2.0).pow(exp) / 0x100000000
+        return if (sign) -result else result
+    }
+
+    fun makeFloatFillAsm(): String {
+        val b0 = "$" + 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"
+    }
+}

codeCore/src/prog8/code/target/cx16/CX16MachineDefinition.kt

@@ -0,0 +1,77 @@
+package prog8.code.target.cx16
+
+import prog8.code.core.*
+import prog8.code.target.cbm.Mflpt5
+import java.nio.file.Path
+
+
+class CX16MachineDefinition: IMachineDefinition {
+
+    override val cpu = CpuType.CPU65c02
+
+    override val FLOAT_MAX_POSITIVE = Mflpt5.FLOAT_MAX_POSITIVE
+    override val FLOAT_MAX_NEGATIVE = Mflpt5.FLOAT_MAX_NEGATIVE
+    override val FLOAT_MEM_SIZE = Mflpt5.FLOAT_MEM_SIZE
+    override val PROGRAM_LOAD_ADDRESS = 0x0801u
+
+    // the 2*256 byte evaluation stack (on which bytes, words, and even floats are stored during calculations)
+    override var ESTACK_LO = 0x0400u        //  $0400-$04ff inclusive
+    override var ESTACK_HI = 0x0500u        //  $0500-$05ff inclusive
+
+    override lateinit var zeropage: Zeropage
+
+    override fun getFloatAsmBytes(num: Number) = Mflpt5.fromNumber(num).makeFloatFillAsm()
+    override fun importLibs(compilerOptions: CompilationOptions, compilationTargetName: String): List<String> {
+        return if (compilerOptions.launcher == CbmPrgLauncherType.BASIC || compilerOptions.output == OutputType.PRG)
+            listOf("syslib")
+        else
+            emptyList()
+    }
+
+    override fun launchEmulator(selectedEmulator: Int, programNameWithPath: Path) {
+        val emulator: String
+        val extraArgs: List<String>
+
+        when(selectedEmulator) {
+            1 -> {
+                emulator = "x16emu"
+                extraArgs = emptyList()
+            }
+            2 -> {
+                emulator = "box16"
+                extraArgs = listOf("-sym", viceMonListName(programNameWithPath.toString()))
+            }
+            else -> {
+                System.err.println("Cx16 target only supports x16emu and box16 emulators.")
+                return
+            }
+        }
+
+        println("\nStarting Commander X16 emulator $emulator...")
+        val cmdline = listOf(emulator, "-scale", "2", "-run", "-prg", "${programNameWithPath}.prg") + extraArgs
+        val processb = ProcessBuilder(cmdline).inheritIO()
+        val process: Process = processb.start()
+        process.waitFor()
+    }
+
+    override fun isIOAddress(address: UInt): Boolean = address==0u || address==1u || address in 0x9f00u..0x9fffu
+
+    override fun initializeZeropage(compilerOptions: CompilationOptions) {
+        zeropage = CX16Zeropage(compilerOptions)
+    }
+
+    // 65c02 opcodes, these cannot be used as variable or label names
+    override val opcodeNames = setOf("adc", "and", "asl", "bcc", "bcs",
+            "beq", "bge", "bit", "blt", "bmi", "bne", "bpl", "brk", "bvc", "bvs", "clc",
+            "cld", "cli", "clv", "cmp", "cpx", "cpy", "dec", "dex", "dey",
+            "eor", "gcc", "gcs", "geq", "gge", "glt", "gmi", "gne", "gpl", "gvc", "gvs",
+            "inc", "inx", "iny", "jmp", "jsr",
+            "lda", "ldx", "ldy", "lsr", "nop", "ora", "pha", "php",
+            "pla", "plp", "rol", "ror", "rti", "rts", "sbc",
+            "sec", "sed", "sei",
+            "sta", "stx", "sty", "tax", "tay", "tsx", "txa", "txs", "tya",
+            "bra", "phx", "phy", "plx", "ply", "stz", "trb", "tsb", "bbr", "bbs",
+            "rmb", "smb", "stp", "wai")
+
+
+}

codeCore/src/prog8/code/target/cx16/CX16Zeropage.kt

@@ -0,0 +1,69 @@
+package prog8.code.target.cx16
+
+import prog8.code.core.*
+
+
+class CX16Zeropage(options: CompilationOptions) : Zeropage(options) {
+
+    override val SCRATCH_B1 = 0x7au      // temp storage for a single byte
+    override val SCRATCH_REG = 0x7bu     // temp storage for a register, must be B1+1
+    override val SCRATCH_W1 = 0x7cu      // temp storage 1 for a word  $7c+$7d
+    override val SCRATCH_W2 = 0x7eu      // temp storage 2 for a word  $7e+$7f
+
+
+    init {
+        if (options.floats && options.zeropage !in arrayOf(
+                ZeropageType.FLOATSAFE,
+                ZeropageType.BASICSAFE,
+                ZeropageType.DONTUSE
+            ))
+            throw InternalCompilerException("when floats are enabled, zero page type should be 'floatsafe' or 'basicsafe' or 'dontuse'")
+
+        // the addresses 0x02 to 0x21 (inclusive) are taken for sixteen virtual 16-bit api registers.
+
+        synchronized(this) {
+            when (options.zeropage) {
+                ZeropageType.FULL -> {
+                    free.addAll(0x22u..0xffu)
+                }
+                ZeropageType.KERNALSAFE -> {
+                    free.addAll(0x22u..0x7fu)
+                    free.addAll(0xa9u..0xffu)
+                }
+                ZeropageType.FLOATSAFE -> {
+                    free.addAll(0x22u..0x7fu)
+                    free.addAll(0xd4u..0xffu)
+                }
+                ZeropageType.BASICSAFE -> {
+                    free.addAll(0x22u..0x7fu)
+                }
+                ZeropageType.DONTUSE -> {
+                    free.clear() // don't use zeropage at all
+                }
+                else -> throw InternalCompilerException("for this machine target, zero page type 'floatsafe' is not available. ${options.zeropage}")
+            }
+
+            val distictFree = free.distinct()
+            free.clear()
+            free.addAll(distictFree)
+
+            removeReservedFromFreePool()
+
+            allocateCx16VirtualRegisters()
+        }
+    }
+
+    override fun allocateCx16VirtualRegisters() {
+        // Note: the 16 virtual registers R0-R15 are not regular allocated variables, they're *memory mapped* elsewhere to fixed addresses.
+        // However, to be able for the compiler to "see" them as zero page variables, we have to register them here as well.
+        // This is important because the compiler sometimes treats ZP variables more efficiently (for example if it's a pointer)
+        for(reg in 0..15) {
+            allocatedVariables[listOf("cx16", "r${reg}")]   = ZpAllocation((2+reg*2).toUInt(), DataType.UWORD, 2)       // cx16.r0 .. cx16.r15
+            allocatedVariables[listOf("cx16", "r${reg}s")]  = ZpAllocation((2+reg*2).toUInt(), DataType.WORD, 2)        // cx16.r0s .. cx16.r15s
+            allocatedVariables[listOf("cx16", "r${reg}L")]  = ZpAllocation((2+reg*2).toUInt(), DataType.UBYTE, 1)       // cx16.r0L .. cx16.r15L
+            allocatedVariables[listOf("cx16", "r${reg}H")]  = ZpAllocation((3+reg*2).toUInt(), DataType.UBYTE, 1)       // cx16.r0H .. cx16.r15H
+            allocatedVariables[listOf("cx16", "r${reg}sL")] = ZpAllocation((2+reg*2).toUInt(), DataType.BYTE, 1)        // cx16.r0sL .. cx16.r15sL
+            allocatedVariables[listOf("cx16", "r${reg}sH")] = ZpAllocation((3+reg*2).toUInt(), DataType.BYTE, 1)        // cx16.r0sH .. cx16.r15sH
+        }
+    }
+}

codeCore/src/prog8/code/target/virtual/VirtualMachineDefinition.kt

@@ -0,0 +1,57 @@
+package prog8.code.target.virtual
+
+import prog8.code.core.CompilationOptions
+import prog8.code.core.CpuType
+import prog8.code.core.IMachineDefinition
+import prog8.code.core.Zeropage
+import java.io.File
+import java.nio.file.Path
+import kotlin.io.path.name
+import kotlin.io.path.readText
+
+
+class VirtualMachineDefinition: IMachineDefinition {
+
+    override val cpu = CpuType.VIRTUAL
+
+    override val FLOAT_MAX_POSITIVE = Float.MAX_VALUE.toDouble()
+    override val FLOAT_MAX_NEGATIVE = -Float.MAX_VALUE.toDouble()
+    override val FLOAT_MEM_SIZE = 4             // 32-bits floating point
+    override val PROGRAM_LOAD_ADDRESS = 0u      // not actually used
+
+    override var ESTACK_LO = 0u                 // not actually used
+    override var ESTACK_HI = 0u                 // not actually used
+
+    override lateinit var zeropage: Zeropage     // not actually used
+
+    override fun getFloatAsmBytes(num: Number) = TODO("float asm bytes from number")
+
+    override fun importLibs(compilerOptions: CompilationOptions, compilationTargetName: String): List<String> {
+        return listOf("syslib")
+    }
+
+    override fun launchEmulator(selectedEmulator: Int, programNameWithPath: Path) {
+        println("\nStarting Virtual Machine...")
+        // to not have external module dependencies we launch the virtual machine via reflection
+        val vm = Class.forName("prog8.vm.VmRunner").getDeclaredConstructor().newInstance() as IVirtualMachineRunner
+        val filename = programNameWithPath.name
+        if(filename.endsWith(".p8virt")) {
+            vm.runProgram(programNameWithPath.readText(), true)
+        } else if(File("$filename.p8virt").isFile) {
+            val source = File("$filename.p8virt").readText()
+            vm.runProgram(source, true)
+        }
+        else
+            throw IllegalArgumentException("vm can only run .p8virt or .p8ir files")
+    }
+
+    override fun isIOAddress(address: UInt): Boolean = false
+
+    override fun initializeZeropage(compilerOptions: CompilationOptions) {}
+
+    override val opcodeNames = emptySet<String>()
+}
+
+interface IVirtualMachineRunner {
+    fun runProgram(source: String, throttle: Boolean)
+}

codeGenCpu6502/build.gradle

@@ -0,0 +1,46 @@
+
+plugins {
+    id 'java'
+    id 'application'
+    id "org.jetbrains.kotlin.jvm"
+}
+
+java {
+    toolchain {
+        languageVersion = JavaLanguageVersion.of(javaVersion)
+    }
+}
+
+compileKotlin {
+    kotlinOptions {
+        jvmTarget = javaVersion
+    }
+}
+
+compileTestKotlin {
+    kotlinOptions {
+        jvmTarget = javaVersion
+    }
+}
+
+dependencies {
+    implementation project(':codeCore')
+    implementation project(':compilerAst')
+    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8"
+    // implementation "org.jetbrains.kotlin:kotlin-reflect"
+    implementation "com.michael-bull.kotlin-result:kotlin-result-jvm:1.1.16"
+
+}
+
+sourceSets {
+    main {
+        java {
+            srcDirs = ["${project.projectDir}/src"]
+        }
+        resources {
+            srcDirs = ["${project.projectDir}/res"]
+        }
+    }
+}
+
+// note: there are no unit tests in this module!

codeGenCpu6502/codeGenCpu6502.iml

@@ -0,0 +1,16 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<module type="JAVA_MODULE" version="4">
+  <component name="NewModuleRootManager" inherit-compiler-output="true">
+    <exclude-output />
+    <content url="file://$MODULE_DIR$">
+      <sourceFolder url="file://$MODULE_DIR$/src" isTestSource="false" />
+      <excludeFolder url="file://$MODULE_DIR$/build" />
+    </content>
+    <orderEntry type="inheritedJdk" />
+    <orderEntry type="sourceFolder" forTests="false" />
+    <orderEntry type="library" name="KotlinJavaRuntime" level="project" />
+    <orderEntry type="module" module-name="codeCore" />
+    <orderEntry type="module" module-name="compilerAst" />
+    <orderEntry type="library" name="michael.bull.kotlin.result.jvm" level="project" />
+  </component>
+</module>

codeGenCpu6502/src/prog8/codegen/cpu6502/AsmOptimizer.kt

@@ -0,0 +1,501 @@
+package prog8.codegen.cpu6502
+
+import prog8.ast.Program
+import prog8.ast.expressions.NumericLiteral
+import prog8.ast.statements.VarDecl
+import prog8.ast.statements.VarDeclType
+import prog8.code.core.IMachineDefinition
+
+
+// note: see https://wiki.nesdev.org/w/index.php/6502_assembly_optimisations
+
+
+internal fun optimizeAssembly(lines: MutableList<String>, machine: IMachineDefinition, program: Program): Int {
+
+    var numberOfOptimizations = 0
+
+    var linesByFour = getLinesBy(lines, 4)
+
+    var mods = optimizeUselessStackByteWrites(linesByFour)
+    if(mods.isNotEmpty()) {
+        apply(mods, lines)
+        linesByFour = getLinesBy(lines, 4)
+        numberOfOptimizations++
+    }
+
+    mods = optimizeIncDec(linesByFour)
+    if(mods.isNotEmpty()) {
+        apply(mods, lines)
+        linesByFour = getLinesBy(lines, 4)
+        numberOfOptimizations++
+    }
+
+    mods = optimizeCmpSequence(linesByFour)
+    if(mods.isNotEmpty()) {
+        apply(mods, lines)
+        linesByFour = getLinesBy(lines, 4)
+        numberOfOptimizations++
+    }
+
+    mods = optimizeStoreLoadSame(linesByFour, machine, program)
+    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)
+    mods = optimizeSameAssignments(linesByFourteen, machine, program)
+    if(mods.isNotEmpty()) {
+        apply(mods, lines)
+        linesByFourteen = getLinesBy(lines, 14)
+        numberOfOptimizations++
+    }
+
+    mods = optimizeSamePointerIndexing(linesByFourteen, machine, program)
+    if(mods.isNotEmpty()) {
+        apply(mods, lines)
+        linesByFourteen = getLinesBy(lines, 14)
+        numberOfOptimizations++
+    }
+
+    // TODO more assembly peephole optimizations
+
+    return numberOfOptimizations
+}
+
+private fun String.isBranch() = this.startsWith("b")
+private fun String.isStoreReg() = this.startsWith("sta") || this.startsWith("sty") || this.startsWith("stx")
+private fun String.isStoreRegOrZero() = this.isStoreReg() || this.startsWith("stz")
+private fun String.isLoadReg() = this.startsWith("lda") || this.startsWith("ldy") || this.startsWith("ldx")
+
+private class Modification(val lineIndex: Int, val remove: Boolean, val replacement: String?)
+
+private fun apply(modifications: List<Modification>, lines: MutableList<String>) {
+    for (modification in modifications.sortedBy { it.lineIndex }.reversed()) {
+        if(modification.remove)
+            lines.removeAt(modification.lineIndex)
+        else
+            lines[modification.lineIndex] = modification.replacement!!
+    }
+}
+
+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)
+
+private fun optimizeCmpSequence(linesByFour: List<List<IndexedValue<String>>>): List<Modification> {
+    // 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>>>, machine: IMachineDefinition, program: Program): List<Modification> {
+
+    // Optimize sequential assignments of the same value to various targets (bytes, words, floats)
+    // the float one is the one that requires 2*7=14 lines of code to check...
+    // The better place to do this is in the Compiler instead and never create these types of assembly, but hey
+
+    val mods = mutableListOf<Modification>()
+    for (lines in linesByFourteen) {
+        val first = lines[0].value.trimStart()
+        val second = lines[1].value.trimStart()
+        val third = lines[2].value.trimStart()
+        val fourth = lines[3].value.trimStart()
+        val fifth = lines[4].value.trimStart()
+        val sixth = lines[5].value.trimStart()
+        val seventh = lines[6].value.trimStart()
+        val eighth = lines[7].value.trimStart()
+
+        if(first.startsWith("lda") && second.startsWith("ldy") && third.startsWith("sta") && fourth.startsWith("sty") &&
+                fifth.startsWith("lda") && sixth.startsWith("ldy") && seventh.startsWith("sta") && eighth.startsWith("sty")) {
+            val firstvalue = first.substring(4)
+            val secondvalue = second.substring(4)
+            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)
+                val address1 = getAddressArg(first, program)
+                val address2 = getAddressArg(second, program)
+                if(address1==null || address2==null || (!machine.isIOAddress(address1) && !machine.isIOAddress(address2))) {
+                    mods.add(Modification(lines[4].index, true, null))
+                    mods.add(Modification(lines[5].index, true, null))
+                }
+            }
+        }
+
+        if(first.startsWith("lda") && second.startsWith("sta") && third.startsWith("lda") && fourth.startsWith("sta")) {
+            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)
+                val address = getAddressArg(first, program)
+                if(address==null || !machine.isIOAddress(address))
+                    mods.add(Modification(lines[2].index, true, null))
+            }
+        }
+
+        if(first.startsWith("lda") && second.startsWith("ldy") && third.startsWith("sta") && fourth.startsWith("sty") &&
+                fifth.startsWith("lda") && sixth.startsWith("ldy") &&
+                (seventh.startsWith("jsr  floats.copy_float") || seventh.startsWith("jsr  cx16flt.copy_float"))) {
+
+            val nineth = lines[8].value.trimStart()
+            val tenth = lines[9].value.trimStart()
+            val eleventh = lines[10].value.trimStart()
+            val twelveth = lines[11].value.trimStart()
+            val thirteenth = lines[12].value.trimStart()
+            val fourteenth = lines[13].value.trimStart()
+
+            if(eighth.startsWith("lda") && nineth.startsWith("ldy") && tenth.startsWith("sta") && eleventh.startsWith("sty") &&
+                    twelveth.startsWith("lda") && thirteenth.startsWith("ldy") &&
+                    (fourteenth.startsWith("jsr  floats.copy_float") || fourteenth.startsWith("jsr  cx16flt.copy_float"))) {
+
+                if(first.substring(4) == eighth.substring(4) && second.substring(4)==nineth.substring(4)) {
+                    // identical float init
+                    mods.add(Modification(lines[7].index, true, null))
+                    mods.add(Modification(lines[8].index, true, null))
+                    mods.add(Modification(lines[9].index, true, null))
+                    mods.add(Modification(lines[10].index, true, null))
+                }
+            }
+        }
+
+        var overlappingMods = false
+        /*
+        sta  prog8_lib.retval_intermX      ; remove
+        sty  prog8_lib.retval_intermY      ; remove
+        lda  prog8_lib.retval_intermX      ; remove
+        ldy  prog8_lib.retval_intermY      ; remove
+        sta  A1
+        sty  A2
+         */
+        if(first.isStoreReg() && second.isStoreReg()
+            && third.isLoadReg() && fourth.isLoadReg()
+            && fifth.isStoreReg() && sixth.isStoreReg()) {
+            val reg1 = first[2]
+            val reg2 = second[2]
+            val reg3 = third[2]
+            val reg4 = fourth[2]
+            val reg5 = fifth[2]
+            val reg6 = sixth[2]
+            if (reg1 == reg3 && reg1 == reg5 && reg2 == reg4 && reg2 == reg6) {
+                val firstvalue = first.substring(4)
+                val secondvalue = second.substring(4)
+                val thirdvalue = third.substring(4)
+                val fourthvalue = fourth.substring(4)
+                if(firstvalue.contains("prog8_lib.retval_interm") && secondvalue.contains("prog8_lib.retval_interm")
+                    && firstvalue==thirdvalue && secondvalue==fourthvalue) {
+                    mods.add(Modification(lines[0].index, true, null))
+                    mods.add(Modification(lines[1].index, true, null))
+                    mods.add(Modification(lines[2].index, true, null))
+                    mods.add(Modification(lines[3].index, true, null))
+                    overlappingMods = true
+                }
+            }
+        }
+
+        /*
+        sta  A1
+        sty  A2
+        lda  A1     ; can be removed
+        ldy  A2     ; can be removed if not followed by a branch instuction
+         */
+        if(!overlappingMods && first.isStoreReg() && second.isStoreReg()
+            && third.isLoadReg() && fourth.isLoadReg()) {
+            val reg1 = first[2]
+            val reg2 = second[2]
+            val reg3 = third[2]
+            val reg4 = fourth[2]
+            if(reg1==reg3 && reg2==reg4) {
+                val firstvalue = first.substring(4)
+                val secondvalue = second.substring(4)
+                val thirdvalue = third.substring(4)
+                val fourthvalue = fourth.substring(4)
+                if(firstvalue==thirdvalue && secondvalue == fourthvalue) {
+                    val address = getAddressArg(first, program)
+                    if(address==null || !machine.isIOAddress(address)) {
+                        overlappingMods = true
+                        mods.add(Modification(lines[2].index, true, null))
+                        if (!fifth.startsWith('b'))
+                            mods.add(Modification(lines[3].index, true, null))
+                    }
+                }
+            }
+        }
+
+        /*
+        sta  A1
+        sty  A2     ; ... or stz
+        lda  A1     ; can be removed if not followed by a branch instruction
+         */
+        if(!overlappingMods && first.isStoreReg() && second.isStoreRegOrZero()
+            && third.isLoadReg() && !fourth.isBranch()) {
+            val reg1 = first[2]
+            val reg3 = third[2]
+            if(reg1==reg3) {
+                val firstvalue = first.substring(4)
+                val thirdvalue = third.substring(4)
+                if(firstvalue==thirdvalue) {
+                    val address = getAddressArg(first, program)
+                    if(address==null || !machine.isIOAddress(address)) {
+                        overlappingMods = true
+                        mods.add(Modification(lines[2].index, true, null))
+                    }
+                }
+            }
+        }
+
+        /*
+        sta  A1
+        ldy  A1     ; make tay
+        sta  A1     ; remove
+         */
+        if(!overlappingMods && first.startsWith("sta") && second.isLoadReg()
+            && third.startsWith("sta") && second.length>4) {
+            val firstvalue = first.substring(4)
+            val secondvalue = second.substring(4)
+            val thirdvalue = third.substring(4)
+            if(firstvalue==secondvalue && firstvalue==thirdvalue) {
+                val address = getAddressArg(first, program)
+                if(address==null || !machine.isIOAddress(address)) {
+                    overlappingMods = true
+                    val reg2 = second[2]
+                    mods.add(Modification(lines[1].index, false, "  ta$reg2"))
+                    mods.add(Modification(lines[2].index, true, null))
+                }
+            }
+        }
+
+        /*
+        sta  A   ; or stz     double store, remove this first one
+        sta  A   ; or stz
+         */
+        if(!overlappingMods && first.isStoreRegOrZero() && second.isStoreRegOrZero()) {
+            if(first[2]==second[2]) {
+                val firstvalue = first.substring(4)
+                val secondvalue = second.substring(4)
+                if(firstvalue==secondvalue) {
+                    val address = getAddressArg(first, program)
+                    if(address==null || !machine.isIOAddress(address)) {
+                        overlappingMods = true
+                        mods.add(Modification(lines[0].index, true, null))
+                    }
+                }
+            }
+        }
+    }
+
+    return mods
+}
+
+private fun optimizeSamePointerIndexing(linesByFourteen: List<List<IndexedValue<String>>>, machine: IMachineDefinition, program: Program): List<Modification> {
+
+    // Optimize same pointer indexing where for instance we load and store to the same ptr index in Y
+    // if Y isn't modified in between we can omit the second LDY:
+    //    ldy  #0
+    //    lda  (ptr),y
+    //    ora  #3       ; <-- instruction(s) that don't modify Y
+    //    ldy  #0       ; <-- can be removed
+    //    sta  (ptr),y
+
+    val mods = mutableListOf<Modification>()
+    for (lines in linesByFourteen) {
+        val first = lines[0].value.trimStart()
+        val second = lines[1].value.trimStart()
+        val third = lines[2].value.trimStart()
+        val fourth = lines[3].value.trimStart()
+        val fifth = lines[4].value.trimStart()
+        val sixth = lines[5].value.trimStart()
+
+        if(first.startsWith("ldy") && second.startsWith("lda") && fourth.startsWith("ldy") && fifth.startsWith("sta")) {
+            val firstvalue = first.substring(4)
+            val secondvalue = second.substring(4)
+            val fourthvalue = fourth.substring(4)
+            val fifthvalue = fifth.substring(4)
+            if("y" !in third && firstvalue==fourthvalue && secondvalue==fifthvalue && secondvalue.endsWith(",y") && fifthvalue.endsWith(",y")) {
+                mods.add(Modification(lines[3].index, true, null))
+            }
+        }
+        if(first.startsWith("ldy") && second.startsWith("lda") && fifth.startsWith("ldy") && sixth.startsWith("sta")) {
+            val firstvalue = first.substring(4)
+            val secondvalue = second.substring(4)
+            val fifthvalue = fifth.substring(4)
+            val sixthvalue = sixth.substring(4)
+            if("y" !in third && "y" !in fourth && firstvalue==fifthvalue && secondvalue==sixthvalue && secondvalue.endsWith(",y") && sixthvalue.endsWith(",y")) {
+                mods.add(Modification(lines[4].index, true, null))
+            }
+        }
+    }
+
+    return mods
+}
+
+private fun optimizeStoreLoadSame(linesByFour: List<List<IndexedValue<String>>>, machine: IMachineDefinition, program: Program): List<Modification> {
+    // sta X + lda X,  sty X + ldy X,   stx X + ldx X  -> the second instruction can OFTEN be eliminated
+    val mods = mutableListOf<Modification>()
+    for (lines in linesByFour) {
+        val first = lines[1].value.trimStart()
+        val second = lines[2].value.trimStart()
+
+        if ((first.startsWith("sta ") && second.startsWith("lda ")) ||
+                (first.startsWith("stx ") && second.startsWith("ldx ")) ||
+                (first.startsWith("sty ") && second.startsWith("ldy ")) ||
+                (first.startsWith("lda ") && second.startsWith("lda ")) ||
+                (first.startsWith("ldy ") && second.startsWith("ldy ")) ||
+                (first.startsWith("ldx ") && second.startsWith("ldx ")) ||
+                (first.startsWith("sta ") && second.startsWith("lda ")) ||
+                (first.startsWith("sty ") && second.startsWith("ldy ")) ||
+                (first.startsWith("stx ") && second.startsWith("ldx "))
+        ) {
+            val third = lines[3].value.trimStart()
+            val attemptRemove =
+                if(third.isBranch()) {
+                    // a branch instruction follows, we can only remove the load instruction if
+                    // another load instruction of the same register precedes the store instruction
+                    // (otherwise wrong cpu flags are used)
+                    val loadinstruction = second.substring(0, 3)
+                    lines[0].value.trimStart().startsWith(loadinstruction)
+                }
+                else {
+                    // no branch instruction follows, we can remove the load instruction
+                    val address = getAddressArg(lines[2].value, program)
+                    address==null || !machine.isIOAddress(address)
+                }
+
+            if(attemptRemove) {
+                val firstLoc = first.substring(4).trimStart()
+                val secondLoc = second.substring(4).trimStart()
+                if (firstLoc == secondLoc)
+                    mods.add(Modification(lines[2].index, true, null))
+            }
+        }
+        else if(first=="pha" && second=="pla" ||
+            first=="phx" && second=="plx" ||
+            first=="phy" && second=="ply" ||
+            first=="php" && second=="plp") {
+            mods.add(Modification(lines[1].index, true, null))
+            mods.add(Modification(lines[2].index, true, null))
+        } else if(first=="pha" && second=="plx") {
+            mods.add(Modification(lines[1].index, true, null))
+            mods.add(Modification(lines[2].index, false, "  tax"))
+        } else if(first=="pha" && second=="ply") {
+            mods.add(Modification(lines[1].index, true, null))
+            mods.add(Modification(lines[2].index, false, "  tay"))
+        } else if(first=="phx" && second=="pla") {
+            mods.add(Modification(lines[1].index, true, null))
+            mods.add(Modification(lines[2].index, false, "  txa"))
+        } else if(first=="phx" && second=="ply") {
+            mods.add(Modification(lines[1].index, true, null))
+            mods.add(Modification(lines[2].index, false, "  txy"))
+        } else if(first=="phy" && second=="pla") {
+            mods.add(Modification(lines[1].index, true, null))
+            mods.add(Modification(lines[2].index, false, "  tya"))
+        } else if(first=="phy" && second=="plx") {
+            mods.add(Modification(lines[1].index, true, null))
+            mods.add(Modification(lines[2].index, false, "  tyx"))
+        }
+    }
+    return mods
+}
+
+private val identifierRegex = Regex("""^([a-zA-Z_$][a-zA-Z\d_\.$]*)""")
+
+private fun getAddressArg(line: String, program: Program): UInt? {
+    val loadArg = line.trimStart().substring(3).trim()
+    return when {
+        loadArg.startsWith('$') -> loadArg.substring(1).toUIntOrNull(16)
+        loadArg.startsWith('%') -> loadArg.substring(1).toUIntOrNull(2)
+        loadArg.startsWith('#') -> null
+        loadArg.startsWith('(') -> null
+        loadArg[0].isLetter() -> {
+            val identMatch = identifierRegex.find(loadArg)
+            if(identMatch!=null) {
+                val identifier = identMatch.value
+                val decl = program.toplevelModule.lookup(identifier.split(".")) as? VarDecl
+                if(decl!=null) {
+                    when(decl.type){
+                        VarDeclType.VAR -> null
+                        VarDeclType.CONST,
+                        VarDeclType.MEMORY -> (decl.value as NumericLiteral).number.toUInt()
+                    }
+                }
+                else null
+            } else null
+        }
+        else -> loadArg.substring(1).toUIntOrNull()
+    }
+}
+
+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 mods = mutableListOf<Modification>()
+    for (lines in linesByFour) {
+        val first = lines[0].value
+        val second = lines[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)
+                || (" ina" in first || "\tina" in first) && (" dea" in second || "\tdea" in second)
+                || (" inc  a" in first || "\tinc  a" in first) && (" dec  a" in second || "\tdec  a" 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)
+                || (" dea" in first || "\tdea" in first) && (" ina" in second || "\tina" in second)
+                || (" dec  a" in first || "\tdec  a" in first) && (" inc  a" in second || "\tinc  a" in second)) {
+            mods.add(Modification(lines[0].index, true, null))
+            mods.add(Modification(lines[1].index, true, null))
+        }
+    }
+    return mods
+}
+
+private fun optimizeJsrRts(linesByFour: List<List<IndexedValue<String>>>): List<Modification> {
+    // jsr Sub + rts -> jmp Sub
+    val mods = mutableListOf<Modification>()
+    for (lines in linesByFour) {
+        val first = lines[0].value
+        val second = lines[1].value
+        if ((" jsr" in first || "\tjsr" in first ) && (" rts" in second || "\trts" in second)) {
+            mods += Modification(lines[0].index, false, lines[0].value.replace("jsr", "jmp"))
+            mods += Modification(lines[1].index, true, null)
+        }
+    }
+    return mods
+}

codeGenCpu6502/src/prog8/codegen/cpu6502/AsmsubHelpers.kt

@@ -0,0 +1,61 @@
+package prog8.codegen.cpu6502
+
+import prog8.ast.expressions.ArrayIndexedExpression
+import prog8.ast.expressions.BuiltinFunctionCall
+import prog8.ast.expressions.Expression
+import prog8.ast.statements.Subroutine
+import prog8.code.core.Cx16VirtualRegisters
+import prog8.code.core.RegisterOrPair
+import prog8.code.core.RegisterOrStatusflag
+
+
+fun asmsub6502ArgsEvalOrder(sub: Subroutine): List<Int> {
+    val order = mutableListOf<Int>()
+    // order is:
+    //  1) cx16 virtual word registers,
+    //  2) paired CPU registers,
+    //  3) single CPU registers (X last), except A,
+    //  4) CPU Carry status flag
+    //  5) the A register itself last   (so everything before it can use the accumulator without having to save its value)
+    val args = sub.parameters.zip(sub.asmParameterRegisters).withIndex()
+    val (cx16regs, args2) = args.partition { it.value.second.registerOrPair in Cx16VirtualRegisters }
+    val pairedRegisters = arrayOf(RegisterOrPair.AX, RegisterOrPair.AY, RegisterOrPair.XY)
+    val (pairedRegs , args3) = args2.partition { it.value.second.registerOrPair in pairedRegisters }
+    val (regsWithoutA, args4) = args3.partition { it.value.second.registerOrPair != RegisterOrPair.A }
+    val (regA, rest) = args4.partition { it.value.second.registerOrPair != null }
+
+    cx16regs.forEach { order += it.index }
+    pairedRegs.forEach { order += it.index }
+    regsWithoutA.forEach {
+        if(it.value.second.registerOrPair != RegisterOrPair.X)
+            order += it.index
+    }
+    regsWithoutA.firstOrNull { it.value.second.registerOrPair==RegisterOrPair.X } ?.let { order += it.index}
+    rest.forEach { order += it.index }
+    regA.forEach { order += it.index }
+    require(order.size==sub.parameters.size)
+    return order
+}
+
+fun asmsub6502ArgsHaveRegisterClobberRisk(args: List<Expression>,
+                                                   paramRegisters: List<RegisterOrStatusflag>): Boolean {
+    fun isClobberRisk(expr: Expression): Boolean {
+        when (expr) {
+            is ArrayIndexedExpression -> {
+                return paramRegisters.any {
+                    it.registerOrPair in listOf(RegisterOrPair.Y, RegisterOrPair.AY, RegisterOrPair.XY)
+                }
+            }
+            is BuiltinFunctionCall -> {
+                if (expr.name == "lsb" || expr.name == "msb")
+                    return isClobberRisk(expr.args[0])
+                if (expr.name == "mkword")
+                    return isClobberRisk(expr.args[0]) && isClobberRisk(expr.args[1])
+                return !expr.isSimple
+            }
+            else -> return !expr.isSimple
+        }
+    }
+
+    return args.size>1 && args.any { isClobberRisk(it) }
+}

codeGenCpu6502/src/prog8/codegen/cpu6502/AssemblyProgram.kt

@@ -0,0 +1,147 @@
+package prog8.codegen.cpu6502
+
+import com.github.michaelbull.result.Ok
+import com.github.michaelbull.result.Result
+import com.github.michaelbull.result.mapError
+import prog8.ast.generatedLabelPrefix
+import prog8.code.core.*
+import java.io.File
+import java.nio.file.Path
+import kotlin.io.path.Path
+import kotlin.io.path.isRegularFile
+
+
+internal class AssemblyProgram(
+        override val name: String,
+        outputDir: Path,
+        private val compTarget: ICompilationTarget) : IAssemblyProgram {
+
+    private val assemblyFile = outputDir.resolve("$name.asm")
+    private val prgFile = outputDir.resolve("$name.prg")        // CBM prg executable program
+    private val xexFile = outputDir.resolve("$name.xex")        // Atari xex executable program
+    private val binFile = outputDir.resolve("$name.bin")
+    private val viceMonListFile = outputDir.resolve(viceMonListName(name))
+    private val listFile = outputDir.resolve("$name.list")
+
+    override fun assemble(options: CompilationOptions): Boolean {
+
+        val assemblerCommand: List<String>
+
+        when (compTarget.name) {
+            in setOf("c64", "c128", "cx16") -> {
+                // CBM machines .prg generation.
+
+                // add "-Wlong-branch"  to see warnings about conversion of branch instructions to jumps (default = do this silently)
+                val command = mutableListOf("64tass", "--ascii", "--case-sensitive", "--long-branch",
+                    "-Wall", "-Wno-strict-bool", "-Wno-shadow", // "-Werror",
+                    "--dump-labels", "--vice-labels", "--labels=$viceMonListFile", "--no-monitor"
+                )
+
+                if(options.asmQuiet)
+                    command.add("--quiet")
+
+                if(options.asmListfile)
+                    command.add("--list=$listFile")
+
+                val outFile = when (options.output) {
+                    OutputType.PRG -> {
+                        command.add("--cbm-prg")
+                        println("\nCreating prg for target ${compTarget.name}.")
+                        prgFile
+                    }
+                    OutputType.RAW -> {
+                        command.add("--nostart")
+                        println("\nCreating raw binary for target ${compTarget.name}.")
+                        binFile
+                    }
+                    else -> throw AssemblyError("invalid output type")
+                }
+                command.addAll(listOf("--output", outFile.toString(), assemblyFile.toString()))
+                assemblerCommand = command
+
+            }
+            "atari" -> {
+                // Atari800XL .xex generation.
+
+                // TODO are these options okay?
+                val command = mutableListOf("64tass", "--ascii", "--case-sensitive", "--long-branch",
+                    "-Wall", "-Wno-strict-bool", "-Wno-shadow", // "-Werror",
+                    "--no-monitor"
+                )
+
+                if(options.asmQuiet)
+                    command.add("--quiet")
+
+                if(options.asmListfile)
+                    command.add("--list=$listFile")
+
+                val outFile = when (options.output) {
+                    OutputType.XEX -> {
+                        command.add("--atari-xex")
+                        println("\nCreating xex for target ${compTarget.name}.")
+                        xexFile
+                    }
+                    OutputType.RAW -> {
+                        command.add("--nostart")
+                        println("\nCreating raw binary for target ${compTarget.name}.")
+                        binFile
+                    }
+                    else -> throw AssemblyError("invalid output type")
+                }
+                command.addAll(listOf("--output", outFile.toString(), assemblyFile.toString()))
+                assemblerCommand = command
+            }
+            else -> throw AssemblyError("invalid compilation target")
+        }
+
+        val proc = ProcessBuilder(assemblerCommand).inheritIO().start()
+        val result = proc.waitFor()
+        if (result == 0 && compTarget.name!="atari") {
+            removeGeneratedLabelsFromMonlist()
+            generateBreakpointList()
+        }
+        return result==0
+    }
+
+    private fun removeGeneratedLabelsFromMonlist() {
+        val pattern = Regex("""al (\w+) \S+${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 viceMonListFile.toFile().readLines()) {
+            val match = pattern.matchEntire(line)
+            if (match != null)
+                breakpoints.add("break \$" + match.groupValues[1])
+        }
+        val num = breakpoints.size
+        breakpoints.add(0, "; vice monitor breakpoint list now follows")
+        breakpoints.add(1, "; $num breakpoints have been defined")
+        breakpoints.add(2, "del")
+        viceMonListFile.toFile().appendText(breakpoints.joinToString("\n") + "\n")
+    }
+}
+
+
+internal fun loadAsmIncludeFile(filename: String, source: SourceCode): Result<String, NoSuchFileException> {
+    return if (filename.startsWith(SourceCode.libraryFilePrefix)) {
+        return com.github.michaelbull.result.runCatching {
+            SourceCode.Resource("/prog8lib/${filename.substring(SourceCode.libraryFilePrefix.length)}").text
+        }.mapError { NoSuchFileException(File(filename)) }
+    } else {
+        val sib = Path(source.origin).resolveSibling(filename)
+        if (sib.isRegularFile())
+            Ok(SourceCode.File(sib).text)
+        else
+            Ok(SourceCode.File(Path(filename)).text)
+    }
+}

codeGenCpu6502/src/prog8/codegen/cpu6502/ExpressionsAsmGen.kt

@@ -0,0 +1,918 @@
+package prog8.codegen.cpu6502
+
+import prog8.ast.Program
+import prog8.ast.expressions.*
+import prog8.code.core.*
+import kotlin.math.absoluteValue
+
+internal class ExpressionsAsmGen(private val program: Program,
+                                 private val asmgen: AsmGen,
+                                 private val allocator: VariableAllocator) {
+
+    @Deprecated("avoid calling this as it generates slow evalstack based code")
+    internal fun translateExpression(expression:Expression) {
+        if (this.asmgen.options.slowCodegenWarnings) {
+            asmgen.errors.warn("slow stack evaluation used for expression $expression", expression.position)
+        }
+        translateExpressionInternal(expression)
+    }
+
+
+    // the rest of the methods are all PRIVATE
+
+
+    private fun translateExpressionInternal(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 -> asmgen.translateDirectMemReadExpressionToRegAorStack(expression, true)
+            is NumericLiteral -> translateExpression(expression)
+            is IdentifierReference -> translateExpression(expression)
+            is FunctionCallExpression -> translateFunctionCallResultOntoStack(expression)
+            is BuiltinFunctionCall -> asmgen.translateBuiltinFunctionCallExpression(expression, true, null)
+            is ContainmentCheck -> throw AssemblyError("containment check as complex expression value is not supported")
+            is ArrayLiteral, is StringLiteral -> throw AssemblyError("no asm gen for string/array literal value assignment - should have been replaced by a variable")
+            is RangeExpression -> throw AssemblyError("range expression should have been changed into array values")
+            is CharLiteral -> throw AssemblyError("charliteral should have been replaced by ubyte using certain encoding")
+            else -> TODO("missing expression asmgen for $expression")
+        }
+    }
+
+    private fun translateFunctionCallResultOntoStack(call: FunctionCallExpression) {
+        // only for use in nested expression evaluation
+
+        val sub = call.target.targetSubroutine(program)!!
+        asmgen.saveXbeforeCall(call)
+        asmgen.translateFunctionCall(call, true)
+        if(sub.regXasResult()) {
+            // store the return value in X somewhere that we can access again below
+            asmgen.out("  stx  P8ZP_SCRATCH_REG")
+        }
+        asmgen.restoreXafterCall(call)
+
+        val returns = sub.returntypes.zip(sub.asmReturnvaluesRegisters)
+        for ((_, reg) in returns) {
+            // result value is in cpu or status registers, put it on the stack instead (as we're evaluating an expression tree)
+            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 -> asmgen.out("  lda  P8ZP_SCRATCH_REG |  sta  P8ESTACK_LO,x |  dex")
+                    RegisterOrPair.AX -> asmgen.out("  sta  P8ESTACK_LO,x |  lda  P8ZP_SCRATCH_REG |  sta  P8ESTACK_HI,x |  dex")
+                    RegisterOrPair.XY -> asmgen.out("  tya |  sta  P8ESTACK_HI,x |  lda  P8ZP_SCRATCH_REG |  sta  P8ESTACK_LO,x |  dex")
+                    RegisterOrPair.FAC1 -> asmgen.out("  jsr  floats.push_fac1")
+                    RegisterOrPair.FAC2 -> asmgen.out("  jsr  floats.push_fac2")
+                    RegisterOrPair.R0,
+                    RegisterOrPair.R1,
+                    RegisterOrPair.R2,
+                    RegisterOrPair.R3,
+                    RegisterOrPair.R4,
+                    RegisterOrPair.R5,
+                    RegisterOrPair.R6,
+                    RegisterOrPair.R7,
+                    RegisterOrPair.R8,
+                    RegisterOrPair.R9,
+                    RegisterOrPair.R10,
+                    RegisterOrPair.R11,
+                    RegisterOrPair.R12,
+                    RegisterOrPair.R13,
+                    RegisterOrPair.R14,
+                    RegisterOrPair.R15 -> {
+                        asmgen.out(
+                            """
+                            lda  cx16.${reg.registerOrPair.toString().lowercase()}
+                            sta  P8ESTACK_LO,x
+                            lda  cx16.${reg.registerOrPair.toString().lowercase()}+1
+                            sta  P8ESTACK_HI,x
+                            dex
+                        """)
+                    }
+                }
+            } else when(reg.statusflag) {
+                Statusflag.Pc -> {
+                    asmgen.out("""
+                        lda  #0
+                        rol  a
+                        sta  P8ESTACK_LO,x
+                        dex""")
+                }
+                Statusflag.Pz -> {
+                    asmgen.out("""
+                        beq  +
+                        lda  #0
+                        beq  ++
++                           lda  #1
++                           sta  P8ESTACK_LO,x
+                        dex""")
+                }
+                Statusflag.Pv -> {
+                    asmgen.out("""
+                        bvs  +
+                        lda  #0
+                        beq  ++
++                           lda  #1
++                           sta  P8ESTACK_LO,x
+                        dex""")
+                }
+                Statusflag.Pn -> {
+                    asmgen.out("""
+                        bmi  +
+                        lda  #0
+                        beq  ++
++                           lda  #1
++                           sta  P8ESTACK_LO,x
+                        dex""")
+                }
+                null -> {}
+            }
+        }
+    }
+
+    private fun translateExpression(typecast: TypecastExpression) {
+        translateExpressionInternal(typecast.expression)
+        when(typecast.expression.inferType(program).getOr(DataType.UNDEFINED)) {
+            DataType.UBYTE, DataType.BOOL -> {
+                when(typecast.type) {
+                    DataType.UBYTE, DataType.BYTE -> {}
+                    DataType.UWORD, DataType.WORD -> {
+                        if(asmgen.isTargetCpu(CpuType.CPU65c02))
+                            asmgen.out("  stz  P8ESTACK_HI+1,x")
+                        else
+                            asmgen.out("  lda  #0  |  sta  P8ESTACK_HI+1,x")
+                    }
+                    DataType.FLOAT -> asmgen.out(" jsr  floats.stack_ub2float")
+                    in PassByReferenceDatatypes -> throw AssemblyError("cannot cast to a pass-by-reference datatype")
+                    else -> throw AssemblyError("weird type")
+                }
+            }
+            DataType.BYTE -> {
+                when(typecast.type) {
+                    DataType.UBYTE, DataType.BYTE -> {}
+                    DataType.UWORD, DataType.WORD -> asmgen.signExtendStackLsb(DataType.BYTE)
+                    DataType.FLOAT -> asmgen.out(" jsr  floats.stack_b2float")
+                    in PassByReferenceDatatypes -> throw AssemblyError("cannot cast to a pass-by-reference datatype")
+                    else -> throw AssemblyError("weird type")
+                }
+            }
+            DataType.UWORD -> {
+                when(typecast.type) {
+                    DataType.BYTE, DataType.UBYTE -> {}
+                    DataType.WORD, DataType.UWORD -> {}
+                    DataType.FLOAT -> asmgen.out(" jsr  floats.stack_uw2float")
+                    in PassByReferenceDatatypes -> throw AssemblyError("cannot cast to a pass-by-reference datatype")
+                    else -> throw AssemblyError("weird type")
+                }
+            }
+            DataType.WORD -> {
+                when(typecast.type) {
+                    DataType.BYTE, DataType.UBYTE -> {}
+                    DataType.WORD, DataType.UWORD -> {}
+                    DataType.FLOAT -> asmgen.out(" jsr  floats.stack_w2float")
+                    in PassByReferenceDatatypes -> throw AssemblyError("cannot cast to a pass-by-reference datatype")
+                    else -> throw AssemblyError("weird type")
+                }
+            }
+            DataType.FLOAT -> {
+                when(typecast.type) {
+                    DataType.UBYTE -> asmgen.out(" jsr  floats.stack_float2uw")
+                    DataType.BYTE -> asmgen.out(" jsr  floats.stack_float2w")
+                    DataType.UWORD -> asmgen.out(" jsr  floats.stack_float2uw")
+                    DataType.WORD -> asmgen.out(" jsr  floats.stack_float2w")
+                    DataType.FLOAT -> {}
+                    in PassByReferenceDatatypes -> throw AssemblyError("cannot cast to a pass-by-reference datatype")
+                    else -> throw AssemblyError("weird type")
+                }
+            }
+            DataType.STR -> {
+                if (typecast.type != DataType.UWORD && typecast.type == DataType.STR)
+                    throw AssemblyError("cannot typecast a string into another incompatitble 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  #>$name  |  sta  P8ESTACK_HI,x  | dex")
+    }
+
+    private fun translateExpression(expr: NumericLiteral) {
+        when(expr.type) {
+            DataType.UBYTE, DataType.BYTE -> asmgen.out(" lda  #${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 = allocator.getFloatAsmConst(expr.number)
+                asmgen.out(" lda  #<$floatConst |  ldy  #>$floatConst |  jsr  floats.push_float")
+            }
+            else -> throw AssemblyError("weird type")
+        }
+    }
+
+    private fun translateExpression(expr: IdentifierReference) {
+        val varname = asmgen.asmVariableName(expr)
+        when(expr.inferType(program).getOr(DataType.UNDEFINED)) {
+            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  #>$varname|  jsr  floats.push_float")
+            }
+            in IterableDatatypes -> {
+                asmgen.out("  lda  #<$varname  |  sta  P8ESTACK_LO,x  |  lda  #>$varname |  sta  P8ESTACK_HI,x |  dex")
+            }
+            else -> throw AssemblyError("stack push weird variable type $expr")
+        }
+    }
+
+    private fun translateExpression(expr: BinaryExpression) {
+        // Uses evalstack to evaluate the given expression.
+        // TODO we're slowly reducing the number of places where this is called and instead replace that by more efficient assignment-form code (using temp var or register for instance).
+        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.getOrElse { throw AssemblyError("unknown dt") }
+        val rightDt = rightIDt.getOrElse { throw AssemblyError("unknown dt") }
+        // see if we can apply some optimized routines
+        when(expr.operator) {
+            "+" -> {
+                if(leftDt in IntegerDatatypes && rightDt in IntegerDatatypes) {
+                    val leftVal = expr.left.constValue(program)?.number?.toInt()
+                    val rightVal = expr.right.constValue(program)?.number?.toInt()
+                    if (leftVal!=null && leftVal in -4..4) {
+                        translateExpressionInternal(expr.right)
+                        if(rightDt in ByteDatatypes) {
+                            val incdec = if(leftVal<0) "dec" else "inc"
+                            repeat(leftVal.absoluteValue) {
+                                asmgen.out("  $incdec  P8ESTACK_LO+1,x")
+                            }
+                        } else {
+                            // word
+                            if(leftVal<0) {
+                                repeat(leftVal.absoluteValue) {
+                                    asmgen.out("""
+                                        lda  P8ESTACK_LO+1,x
+                                        bne  +
+                                        dec  P8ESTACK_HI+1,x
++                                       dec  P8ESTACK_LO+1,x""")
+                                }
+                            } else {
+                                repeat(leftVal) {
+                                    asmgen.out("""
+                                        inc  P8ESTACK_LO+1,x
+                                        bne  +
+                                        inc  P8ESTACK_HI+1,x
++""")
+                                }
+                            }
+                        }
+                        return
+                    }
+                    else if (rightVal!=null && rightVal in -4..4)
+                    {
+                        translateExpressionInternal(expr.left)
+                        if(leftDt in ByteDatatypes) {
+                            val incdec = if(rightVal<0) "dec" else "inc"
+                            repeat(rightVal.absoluteValue) {
+                                asmgen.out("  $incdec  P8ESTACK_LO+1,x")
+                            }
+                        } else {
+                            // word
+                            if(rightVal<0) {
+                                repeat(rightVal.absoluteValue) {
+                                    asmgen.out("""
+                                        lda  P8ESTACK_LO+1,x
+                                        bne  +
+                                        dec  P8ESTACK_HI+1,x
++                                       dec  P8ESTACK_LO+1,x""")
+                                }
+                            } else {
+                                repeat(rightVal) {
+                                    asmgen.out("""
+                                        inc  P8ESTACK_LO+1,x
+                                        bne  +
+                                        inc  P8ESTACK_HI+1,x
++""")
+                                }
+                            }
+                        }
+                        return
+                    }
+                }
+            }
+            "-" -> {
+                if(leftDt in IntegerDatatypes && rightDt in IntegerDatatypes) {
+                    val rightVal = expr.right.constValue(program)?.number?.toInt()
+                    if (rightVal!=null && rightVal in -4..4)
+                    {
+                        translateExpressionInternal(expr.left)
+                        if(leftDt in ByteDatatypes) {
+                            val incdec = if(rightVal<0) "inc" else "dec"
+                            repeat(rightVal.absoluteValue) {
+                                asmgen.out("  $incdec  P8ESTACK_LO+1,x")
+                            }
+                        } else {
+                            // word
+                            if(rightVal>0) {
+                                repeat(rightVal.absoluteValue) {
+                                    asmgen.out("""
+                                        lda  P8ESTACK_LO+1,x
+                                        bne  +
+                                        dec  P8ESTACK_HI+1,x
++                                       dec  P8ESTACK_LO+1,x""")
+                                }
+                            } else {
+                                repeat(rightVal) {
+                                    asmgen.out("""
+                                        inc  P8ESTACK_LO+1,x
+                                        bne  +
+                                        inc  P8ESTACK_HI+1,x
++""")
+                                }
+                            }
+                        }
+                        return
+                    }
+                }
+            }
+            ">>" -> {
+                val amount = expr.right.constValue(program)?.number?.toInt()
+                if(amount!=null) {
+                    translateExpressionInternal(expr.left)
+                    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 -> {
+                            if(amount>=16) {
+                                if(asmgen.isTargetCpu(CpuType.CPU65c02))
+                                    asmgen.out("  stz  P8ESTACK_LO+1,x |  stz  P8ESTACK_HI+1,x")
+                                else
+                                    asmgen.out("  lda  #0 |  sta  P8ESTACK_LO+1,x |  sta  P8ESTACK_HI+1,x")
+                                return
+                            }
+                            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 -> {
+                            if(amount>=16) {
+                                asmgen.out("""
+                                    lda  P8ESTACK_HI+1,x
+                                    bmi  +
+                                    lda  #0
+                                    sta  P8ESTACK_LO+1,x
+                                    sta  P8ESTACK_HI+1,x
+                                    beq  ++
++                                   lda  #255
+                                    sta  P8ESTACK_LO+1,x
+                                    sta  P8ESTACK_HI+1,x
++""")
+                                return
+                            }
+                            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_$left")
+                        }
+                        else -> throw AssemblyError("weird type")
+                    }
+                    return
+                }
+            }
+            "<<" -> {
+                val amount = expr.right.constValue(program)?.number?.toInt()
+                if(amount!=null) {
+                    translateExpressionInternal(expr.left)
+                    if (leftDt in ByteDatatypes) {
+                        if (amount <= 2)
+                            repeat(amount) { asmgen.out("  asl  P8ESTACK_LO+1,x") }
+                        else {
+                            asmgen.out("  lda  P8ESTACK_LO+1,x")
+                            repeat(amount) { asmgen.out("  asl  a") }
+                            asmgen.out("  sta  P8ESTACK_LO+1,x")
+                        }
+                    } else {
+                        var left = amount
+                        while (left >= 7) {
+                            asmgen.out(" jsr  math.shift_left_w_7")
+                            left -= 7
+                        }
+                        if (left in 0..2)
+                            repeat(left) { asmgen.out("  asl  P8ESTACK_LO+1,x |  rol  P8ESTACK_HI+1,x") }
+                        else
+                            asmgen.out(" jsr  math.shift_left_w_$left")
+                    }
+                    return
+                }
+            }
+            "*" -> {
+                if(leftDt in IntegerDatatypes && rightDt in IntegerDatatypes) {
+                    val leftVar = expr.left as? IdentifierReference
+                    val rightVar = expr.right as? IdentifierReference
+                    if(leftVar!=null && rightVar!=null && leftVar==rightVar)
+                        return translateSquared(leftVar, leftDt)
+                }
+
+                val value = expr.right.constValue(program)
+                if(value!=null) {
+                    if(rightDt in IntegerDatatypes) {
+                        val amount = value.number.toInt()
+                        if(amount==2) {
+                            // optimize x*2 common case
+                            translateExpressionInternal(expr.left)
+                            if(leftDt in ByteDatatypes) {
+                                asmgen.out("  asl  P8ESTACK_LO+1,x")
+                            } else {
+                                asmgen.out("  asl  P8ESTACK_LO+1,x |  rol  P8ESTACK_HI+1,x")
+                            }
+                            return
+                        }
+                        when(rightDt) {
+                            DataType.UBYTE -> {
+                                if(amount in asmgen.optimizedByteMultiplications) {
+                                    translateExpressionInternal(expr.left)
+                                    asmgen.out(" jsr  math.stack_mul_byte_$amount")
+                                    return
+                                }
+                            }
+                            DataType.BYTE -> {
+                                if(amount in asmgen.optimizedByteMultiplications) {
+                                    translateExpressionInternal(expr.left)
+                                    asmgen.out(" jsr  math.stack_mul_byte_$amount")
+                                    return
+                                }
+                                if(amount.absoluteValue in asmgen.optimizedByteMultiplications) {
+                                    translateExpressionInternal(expr.left)
+                                    asmgen.out(" jsr  prog8_lib.neg_b |  jsr  math.stack_mul_byte_${amount.absoluteValue}")
+                                    return
+                                }
+                            }
+                            DataType.UWORD -> {
+                                if(amount in asmgen.optimizedWordMultiplications) {
+                                    translateExpressionInternal(expr.left)
+                                    asmgen.out(" jsr  math.stack_mul_word_$amount")
+                                    return
+                                }
+                            }
+                            DataType.WORD -> {
+                                if(amount in asmgen.optimizedWordMultiplications) {
+                                    translateExpressionInternal(expr.left)
+                                    asmgen.out(" jsr  math.stack_mul_word_$amount")
+                                    return
+                                }
+                                if(amount.absoluteValue in asmgen.optimizedWordMultiplications) {
+                                    translateExpressionInternal(expr.left)
+                                    asmgen.out(" jsr  prog8_lib.neg_w |  jsr  math.stack_mul_word_${amount.absoluteValue}")
+                                    return
+                                }
+                            }
+                            else -> {}
+                        }
+                    }
+                }
+            }
+            "/" -> {
+                if(leftDt in IntegerDatatypes && rightDt in IntegerDatatypes) {
+                    val rightVal = expr.right.constValue(program)?.number?.toInt()
+                    if(rightVal!=null && rightVal==2) {
+                        translateExpressionInternal(expr.left)
+                        when (leftDt) {
+                            DataType.UBYTE -> {
+                                asmgen.out("  lsr  P8ESTACK_LO+1,x")
+                            }
+                            DataType.UWORD -> {
+                                asmgen.out("  lsr  P8ESTACK_HI+1,x |  ror  P8ESTACK_LO+1,x")
+                            }
+                            DataType.BYTE -> {
+                                // signed divide using shift needs adjusting of negative value to get correct rounding towards zero
+                                asmgen.out("""
+                                    lda  P8ESTACK_LO+1,x
+                                    bpl  +
+                                    inc  P8ESTACK_LO+1,x
+                                    lda  P8ESTACK_LO+1,x
++                                   asl  a
+                                    ror  P8ESTACK_LO+1,x""")
+                            }
+                            DataType.WORD -> {
+                                // signed divide using shift needs adjusting of negative value to get correct rounding towards zero
+                                asmgen.out("""
+                                    lda  P8ESTACK_HI+1,x
+                                    bpl  ++
+                                    inc  P8ESTACK_LO+1,x
+                                    bne  +
+                                    inc  P8ESTACK_HI+1,x
++                                   lda  P8ESTACK_HI+1,x
++                                   asl  a
+                                    ror  P8ESTACK_HI+1,x
+                                    ror  P8ESTACK_LO+1,x""")
+                            }
+                            else -> throw AssemblyError("weird dt")
+                        }
+                        return
+                    }
+                }
+            }
+            in ComparisonOperators -> {
+                if(leftDt in NumericDatatypes && rightDt in NumericDatatypes) {
+                    val rightVal = expr.right.constValue(program)?.number
+                    if(rightVal==0.0)
+                        return translateComparisonWithZero(expr.left, leftDt, expr.operator)
+                }
+            }
+        }
+
+        if((leftDt in ByteDatatypes && rightDt !in ByteDatatypes)
+                || (leftDt in WordDatatypes && rightDt !in WordDatatypes))
+            throw AssemblyError("binary operator ${expr.operator} left/right dt not identical")
+
+        if(leftDt==DataType.STR && rightDt==DataType.STR && expr.operator in ComparisonOperators) {
+            translateCompareStrings(expr.left, expr.operator, expr.right)
+        }
+        else {
+            // the general, non-optimized cases  TODO optimize more cases.... (or one day just don't use the evalstack at all anymore)
+            translateExpressionInternal(expr.left)
+            translateExpressionInternal(expr.right)
+            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 translateComparisonWithZero(expr: Expression, dt: DataType, operator: String) {
+        if(expr.isSimple) {
+            if(operator=="!=") {
+                when (dt) {
+                    in ByteDatatypes -> {
+                        asmgen.assignExpressionToRegister(expr, RegisterOrPair.A, dt == DataType.BYTE)
+                        asmgen.out("""
+                            beq  +
+                            lda  #1
++                           sta  P8ESTACK_LO,x
+                            dex""")
+                        return
+                    }
+                    in WordDatatypes -> {
+                        asmgen.assignExpressionToRegister(expr, RegisterOrPair.AY, dt == DataType.WORD)
+                        asmgen.out("""
+                            sty  P8ZP_SCRATCH_B1 
+                            ora  P8ZP_SCRATCH_B1
+                            beq  +
+                            lda  #1
++                           sta  P8ESTACK_LO,x
+                            dex""")
+                        return
+                    }
+                    DataType.FLOAT -> {
+                        asmgen.assignExpressionToRegister(expr, RegisterOrPair.FAC1, true)
+                        asmgen.out("""
+                            jsr  floats.SIGN
+                            sta  P8ESTACK_LO,x
+                            dex""")
+                        return
+                    }
+                    else -> {}
+                }
+            }
+            /* operator == is not worth it to special case, the code is mostly larger */
+        }
+        translateExpressionInternal(expr)
+        when(operator) {
+            "==" -> {
+                when(dt) {
+                    DataType.UBYTE, DataType.BYTE -> asmgen.out("  jsr  prog8_lib.equalzero_b")
+                    DataType.UWORD, DataType.WORD -> asmgen.out("  jsr  prog8_lib.equalzero_w")
+                    DataType.FLOAT -> asmgen.out("  jsr  floats.equal_zero")
+                    else -> throw AssemblyError("wrong dt")
+                }
+            }
+            "!=" -> {
+                when(dt) {
+                    DataType.UBYTE, DataType.BYTE -> asmgen.out("  jsr  prog8_lib.notequalzero_b")
+                    DataType.UWORD, DataType.WORD -> asmgen.out("  jsr  prog8_lib.notequalzero_w")
+                    DataType.FLOAT -> asmgen.out("  jsr  floats.notequal_zero")
+                    else -> throw AssemblyError("wrong dt")
+                }
+            }
+            "<" -> {
+                if(dt==DataType.UBYTE || dt==DataType.UWORD)
+                    return translateExpressionInternal(NumericLiteral.fromBoolean(false, expr.position))
+                when(dt) {
+                    DataType.BYTE -> asmgen.out("  jsr  prog8_lib.lesszero_b")
+                    DataType.WORD -> asmgen.out("  jsr  prog8_lib.lesszero_w")
+                    DataType.FLOAT -> asmgen.out("  jsr  floats.less_zero")
+                    else -> throw AssemblyError("wrong dt")
+                }
+            }
+            ">" -> {
+                when(dt) {
+                    DataType.UBYTE -> asmgen.out("  jsr  prog8_lib.greaterzero_ub")
+                    DataType.BYTE -> asmgen.out("  jsr  prog8_lib.greaterzero_sb")
+                    DataType.UWORD -> asmgen.out("  jsr  prog8_lib.greaterzero_uw")
+                    DataType.WORD -> asmgen.out("  jsr  prog8_lib.greaterzero_sw")
+                    DataType.FLOAT -> asmgen.out("  jsr  floats.greater_zero")
+                    else -> throw AssemblyError("wrong dt")
+                }
+            }
+            "<=" -> {
+                when(dt) {
+                    DataType.UBYTE -> asmgen.out("  jsr  prog8_lib.equalzero_b")
+                    DataType.BYTE -> asmgen.out("  jsr  prog8_lib.lessequalzeros_b")
+                    DataType.UWORD -> asmgen.out("  jsr  prog8_lib.equalzero_w")
+                    DataType.WORD -> asmgen.out("  jsr  prog8_lib.lessequalzero_sw")
+                    DataType.FLOAT -> asmgen.out("  jsr  floats.lessequal_zero")
+                    else -> throw AssemblyError("wrong dt")
+                }
+            }
+            ">=" -> {
+                if(dt==DataType.UBYTE || dt==DataType.UWORD)
+                    return translateExpressionInternal(NumericLiteral.fromBoolean(true, expr.position))
+                when(dt) {
+                    DataType.BYTE -> asmgen.out("  jsr  prog8_lib.greaterequalzero_sb")
+                    DataType.WORD -> asmgen.out("  jsr  prog8_lib.greaterequalzero_sw")
+                    DataType.FLOAT -> asmgen.out("  jsr  floats.greaterequal_zero")
+                    else -> throw AssemblyError("wrong dt")
+                }
+            }
+            else -> throw AssemblyError("invalid comparison operator")
+        }
+    }
+
+    private fun translateSquared(variable: IdentifierReference, dt: DataType) {
+        val asmVar = asmgen.asmVariableName(variable)
+        when(dt) {
+            DataType.BYTE, DataType.UBYTE -> {
+                asmgen.out("  lda  $asmVar")
+                asmgen.signExtendAYlsb(dt)
+                asmgen.out("  jsr  math.square")
+            }
+            DataType.UWORD, DataType.WORD -> {
+                asmgen.out("  lda  $asmVar |  ldy  $asmVar+1 |  jsr  math.square")
+            }
+            else -> throw AssemblyError("require integer dt for square")
+        }
+        asmgen.out("  sta  P8ESTACK_LO,x |  tya |  sta  P8ESTACK_HI,x |  dex")
+    }
+
+    private fun translateExpression(expr: PrefixExpression) {
+        translateExpressionInternal(expr.expression)
+        val itype = expr.inferType(program)
+        val type = itype.getOrElse { throw AssemblyError("unknown dt") }
+        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  floats.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")
+                }
+            }
+            else -> throw AssemblyError("invalid prefix operator ${expr.operator}")
+        }
+    }
+
+    private fun translateExpression(arrayExpr: ArrayIndexedExpression) {
+        val elementIDt = arrayExpr.inferType(program)
+        if(!elementIDt.isKnown)
+            throw AssemblyError("unknown dt")
+        val elementDt = elementIDt.getOr(DataType.UNDEFINED)
+        val arrayVarName = asmgen.asmVariableName(arrayExpr.arrayvar)
+
+        val arrayVarDecl = arrayExpr.arrayvar.targetVarDecl(program)!!
+        if(arrayVarDecl.datatype==DataType.UWORD) {
+            // indexing a pointer var instead of a real array or string
+            if(elementDt !in ByteDatatypes)
+                throw AssemblyError("non-array var indexing requires bytes dt")
+            if(arrayExpr.inferType(program) isnot DataType.UBYTE)
+                throw AssemblyError("non-array var indexing requires bytes index")
+            asmgen.loadScaledArrayIndexIntoRegister(arrayExpr, elementDt, CpuRegister.Y)
+            if(asmgen.isZpVar(arrayExpr.arrayvar)) {
+                asmgen.out("  lda  ($arrayVarName),y")
+            } else {
+                asmgen.out("  lda  $arrayVarName |  sta  P8ZP_SCRATCH_W1 |  lda  $arrayVarName+1 |  sta  P8ZP_SCRATCH_W1+1")
+                asmgen.out("  lda  (P8ZP_SCRATCH_W1),y")
+            }
+            asmgen.out("  sta  P8ESTACK_LO,x |  dex")
+            return
+        }
+
+        val constIndexNum = arrayExpr.indexer.constIndex()
+        if(constIndexNum!=null) {
+            val indexValue = constIndexNum * program.memsizer.memorySize(elementDt)
+            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  floats.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  floats.push_float""")
+                }
+                else -> throw AssemblyError("weird dt")
+            }
+
+        }
+    }
+
+    private fun translateBinaryOperatorBytes(operator: String, types: DataType) {
+        when(operator) {
+            "*" -> 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")
+            else -> throw AssemblyError("invalid operator $operator")
+        }
+    }
+
+    private fun translateBinaryOperatorWords(operator: String, dt: DataType) {
+        when(operator) {
+            "*" -> asmgen.out("  jsr  prog8_lib.mul_word")
+            "/" -> asmgen.out(if(dt==DataType.UWORD) "  jsr  prog8_lib.idiv_uw" else "  jsr  prog8_lib.idiv_w")
+            "%" -> {
+                if(dt==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")
+            "<<" -> asmgen.out("  jsr  math.shift_left_w")
+            ">>" -> {
+                if(dt==DataType.UWORD)
+                    asmgen.out("  jsr  math.shift_right_uw")
+                else
+                    asmgen.out("  jsr  math.shift_right_w")
+            }
+            "<" -> asmgen.out(if(dt==DataType.UWORD) "  jsr  prog8_lib.less_uw" else "  jsr  prog8_lib.less_w")
+            ">" -> asmgen.out(if(dt==DataType.UWORD) "  jsr  prog8_lib.greater_uw" else "  jsr  prog8_lib.greater_w")
+            "<=" -> asmgen.out(if(dt==DataType.UWORD) "  jsr  prog8_lib.lesseq_uw" else "  jsr  prog8_lib.lesseq_w")
+            ">=" -> asmgen.out(if(dt==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")
+            else -> throw AssemblyError("invalid operator $operator")
+        }
+    }
+
+    private fun translateBinaryOperatorFloats(operator: String) {
+        when(operator) {
+            "*" -> asmgen.out("  jsr  floats.mul_f")
+            "/" -> asmgen.out("  jsr  floats.div_f")
+            "+" -> asmgen.out("  jsr  floats.add_f")
+            "-" -> asmgen.out("  jsr  floats.sub_f")
+            "<" -> asmgen.out("  jsr  floats.less_f")
+            ">" -> asmgen.out("  jsr  floats.greater_f")
+            "<=" -> asmgen.out("  jsr  floats.lesseq_f")
+            ">=" -> asmgen.out("  jsr  floats.greatereq_f")
+            "==" -> asmgen.out("  jsr  floats.equal_f")
+            "!=" -> asmgen.out("  jsr  floats.notequal_f")
+            "%", "<<", ">>", "&", "^", "|" -> throw AssemblyError("requires integer datatype")
+            else -> throw AssemblyError("invalid operator $operator")
+        }
+    }
+
+    private fun translateCompareStrings(s1: Expression, operator: String, s2: Expression) {
+        asmgen.assignExpressionToVariable(s1, "prog8_lib.strcmp_expression._arg_s1", DataType.UWORD, null)
+        asmgen.assignExpressionToVariable(s2, "prog8_lib.strcmp_expression._arg_s2", DataType.UWORD, null)
+        asmgen.out(" jsr  prog8_lib.strcmp_expression")    // result  of compare is in A
+        when(operator) {
+            "==" -> asmgen.out(" and  #1 |  eor  #1 |  sta  P8ESTACK_LO,x")
+            "!=" -> asmgen.out(" and  #1 |  sta  P8ESTACK_LO,x")
+            "<=" -> asmgen.out("""
+                bpl  +
+                lda  #1
+                bne  ++
++               lda  #0
++               sta  P8ESTACK_LO,x""")
+            ">=" -> asmgen.out("""
+                bmi  +
+                lda  #1
+                bne  ++
++               lda  #0
++               sta  P8ESTACK_LO,x""")
+            "<" -> asmgen.out("""
+                bmi  +
+                lda  #0
+                beq  ++
++               lda  #1
++               sta  P8ESTACK_LO,x""")
+            ">" -> asmgen.out("""
+                bpl  +
+                lda  #0
+                beq  ++
++               lda  #1
++               sta  P8ESTACK_LO,x""")
+        }
+        asmgen.out("  dex")
+    }
+}

codeGenCpu6502/src/prog8/codegen/cpu6502/ForLoopsAsmGen.kt

@@ -1,47 +1,49 @@
-package prog8.compiler.target.c64.codegen
+package prog8.codegen.cpu6502
 
+import com.github.michaelbull.result.fold
 import prog8.ast.Program
-import prog8.ast.base.DataType
 import prog8.ast.expressions.IdentifierReference
-import prog8.ast.expressions.RangeExpr
+import prog8.ast.expressions.RangeExpression
 import prog8.ast.statements.ForLoop
-import prog8.compiler.AssemblyError
+import prog8.code.core.*
-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 class ForLoopsAsmGen(private val program: Program, private val asmgen: AsmGen, private val zeropage: Zeropage) {
 
     internal fun translate(stmt: ForLoop) {
         val iterableDt = stmt.iterable.inferType(program)
         if(!iterableDt.isKnown)
-            throw AssemblyError("can't determine iterable dt")
+            throw AssemblyError("unknown dt")
         when(stmt.iterable) {
-            is RangeExpr -> {
+            is RangeExpression -> {
-                val range = (stmt.iterable as RangeExpr).toConstantIntegerRange()
+                val range = (stmt.iterable as RangeExpression).toConstantIntegerRange()
                 if(range==null) {
-                    translateForOverNonconstRange(stmt, iterableDt.typeOrElse(DataType.STRUCT), stmt.iterable as RangeExpr)
+                    translateForOverNonconstRange(stmt, iterableDt.getOrElse { throw AssemblyError("unknown dt") }, stmt.iterable as RangeExpression)
                 } else {
-                    translateForOverConstRange(stmt, iterableDt.typeOrElse(DataType.STRUCT), range)
+                    translateForOverConstRange(stmt, iterableDt.getOrElse { throw AssemblyError("unknown dt") }, range)
                 }
             }
             is IdentifierReference -> {
-                translateForOverIterableVar(stmt, iterableDt.typeOrElse(DataType.STRUCT), stmt.iterable as IdentifierReference)
+                translateForOverIterableVar(stmt, iterableDt.getOrElse { throw AssemblyError("unknown dt") }, 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) {
+    private fun translateForOverNonconstRange(stmt: ForLoop, iterableDt: DataType, range: RangeExpression) {
-        val loopLabel = asmgen.makeLabel("for_loop")
+        val loopLabel = program.makeLabel("for_loop")
-        val endLabel = asmgen.makeLabel("for_end")
+        val endLabel = program.makeLabel("for_end")
-        val modifiedLabel = asmgen.makeLabel("for_modified")
+        val modifiedLabel = program.makeLabel("for_modified")
-        val modifiedLabel2 = asmgen.makeLabel("for_modifiedb")
+        val modifiedLabel2 = program.makeLabel("for_modifiedb")
         asmgen.loopEndLabels.push(endLabel)
         val stepsize=range.step.constValue(program)!!.number.toInt()
+
+        if(stepsize < -1) {
+            val limit = range.to.constValue(program)?.number
+            if(limit==0.0)
+                throw AssemblyError("for unsigned loop variable it's not possible to count down with step != -1 from a non-const value to exactly zero due to value wrapping")
+        }
+
         when(iterableDt) {
             DataType.ARRAY_B, DataType.ARRAY_UB -> {
                 if (stepsize==1 || stepsize==-1) {
@@ -51,23 +53,17 @@ internal class ForLoopsAsmGen(private val program: Program, private val asmgen:
                     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.assignExpressionToVariable(range.from, varname, ArrayToElementTypes.getValue(iterableDt), null)
-                    asmgen.translateExpression(range.from)
+                    asmgen.assignExpressionToVariable(range.to, "$modifiedLabel+1", ArrayToElementTypes.getValue(iterableDt), null)
-                    asmgen.out("""
+                    asmgen.out(loopLabel)
-                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
+                        $incdec  $varname""")
-                jmp  $loopLabel
+                    asmgen.jmp(loopLabel)
-$endLabel       inx""")
+                    asmgen.out(endLabel)
 
                 } else {
 
@@ -75,36 +71,29 @@ $endLabel       inx""")
 
                     // loop over byte range via loopvar
                     val varname = asmgen.asmVariableName(stmt.loopVar)
-                    asmgen.translateExpression(range.to)
+                    asmgen.assignExpressionToVariable(range.from, varname, ArrayToElementTypes.getValue(iterableDt), null)
-                    asmgen.translateExpression(range.from)
+                    asmgen.assignExpressionToVariable(range.to, "$modifiedLabel+1", ArrayToElementTypes.getValue(iterableDt), null)
-                    asmgen.out("""
+                    asmgen.out(loopLabel)
-                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("""
+                            lda  $varname
                             clc
                             adc  #$stepsize
                             sta  $varname
 $modifiedLabel              cmp  #0    ; modified
-                bcc  $loopLabel
+                            bmi  $loopLabel
                             beq  $loopLabel""")
                     } else {
                         asmgen.out("""
+                            lda  $varname
                             sec
                             sbc  #${stepsize.absoluteValue}
                             sta  $varname
 $modifiedLabel              cmp  #0     ; modified
-                bcs  $loopLabel""")
+                            bpl  $loopLabel""")
                     }
-                    asmgen.out("""
+                    asmgen.out(endLabel)
-$endLabel       inx""")
                 }
             }
             DataType.ARRAY_W, DataType.ARRAY_UW -> {
@@ -113,13 +102,11 @@ $endLabel       inx""")
                     // words, step 1 or -1
 
                     stepsize == 1 || stepsize == -1 -> {
-                        asmgen.translateExpression(range.to)
-                        assignLoopvar(stmt, range)
                         val varname = asmgen.asmVariableName(stmt.loopVar)
+                        assignLoopvar(stmt, range)
+                        asmgen.assignExpressionToRegister(range.to, RegisterOrPair.AY)
                         asmgen.out("""
-                            lda  P8ESTACK_HI+1,x
+                            sty  $modifiedLabel+1
-                            sta  $modifiedLabel+1
-                            lda  P8ESTACK_LO+1,x
                             sta  $modifiedLabel2+1
 $loopLabel""")
                         asmgen.translate(stmt.body)
@@ -134,33 +121,28 @@ $modifiedLabel2 cmp  #0    ; modified
                             asmgen.out("""
 +               inc  $varname
                 bne  $loopLabel
-                inc  $varname+1
+                inc  $varname+1""")
-                jmp  $loopLabel
+                            asmgen.jmp(loopLabel)
-                            """)
                         } else {
                             asmgen.out("""
 +               lda  $varname
                 bne  +
                 dec  $varname+1
-+               dec  $varname
++               dec  $varname""")
-                jmp  $loopLabel""")
+                            asmgen.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)
+                        assignLoopvar(stmt, range)
+                        asmgen.assignExpressionToRegister(range.to, RegisterOrPair.AY)
+                        asmgen.out("""
+                            sty  $modifiedLabel+1
+                            sta  $modifiedLabel2+1
+$loopLabel""")
                         asmgen.translate(stmt.body)
 
                         if (iterableDt == DataType.ARRAY_UW) {
@@ -179,7 +161,7 @@ $modifiedLabel2 lda  #0     ; modified
                 cmp  $varname
                 bcc  $endLabel
                 bcs  $loopLabel
-$endLabel       inx""")
+$endLabel""")
                         } else {
                             asmgen.out("""
                 lda  $varname
@@ -196,22 +178,19 @@ $modifiedLabel  lda  #0   ; modified
                 bvc  +
                 eor  #$80
 +               bpl  $loopLabel                
-$endLabel       inx""")
+$endLabel""")
                         }
                     }
                     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)
+                        assignLoopvar(stmt, range)
+                        asmgen.assignExpressionToRegister(range.to, RegisterOrPair.AY)
+                        asmgen.out("""
+                            sty  $modifiedLabel+1
+                            sta  $modifiedLabel2+1
+$loopLabel""")
                         asmgen.translate(stmt.body)
 
                         if(iterableDt==DataType.ARRAY_UW) {
@@ -229,7 +208,7 @@ $modifiedLabel  cmp  #0    ; modified
                 lda  $varname
 $modifiedLabel2 cmp  #0    ; modified 
                 bcs  $loopLabel
-$endLabel       inx""")
+$endLabel""")
                         } else {
                             asmgen.out("""
                 lda  $varname
@@ -247,7 +226,7 @@ $modifiedLabel  sbc  #0    ; modified
                 bvc  +
                 eor  #$80
 +               bpl  $loopLabel                
-$endLabel       inx""")
+$endLabel""")
                         }
                     }
                 }
@@ -259,11 +238,11 @@ $endLabel       inx""")
     }
 
     private fun translateForOverIterableVar(stmt: ForLoop, iterableDt: DataType, ident: IdentifierReference) {
-        val loopLabel = asmgen.makeLabel("for_loop")
+        val loopLabel = program.makeLabel("for_loop")
-        val endLabel = asmgen.makeLabel("for_end")
+        val endLabel = program.makeLabel("for_end")
         asmgen.loopEndLabels.push(endLabel)
         val iterableName = asmgen.asmVariableName(ident)
-        val decl = ident.targetVarDecl(program.namespace)!!
+        val decl = ident.targetVarDecl(program)!!
         when(iterableDt) {
             DataType.STR -> {
                 asmgen.out("""
@@ -284,7 +263,7 @@ $endLabel""")
             }
             DataType.ARRAY_UB, DataType.ARRAY_B -> {
                 val length = decl.arraysize!!.constIndex()!!
-                val indexVar = asmgen.makeLabel("for_index")
+                val indexVar = program.makeLabel("for_index")
                 asmgen.out("""
                     ldy  #0
 $loopLabel          sty  $indexVar
@@ -306,19 +285,21 @@ $loopLabel          sty  $indexVar
                         bne  $loopLabel
                         beq  $endLabel""")
                 }
-                if(length>=16 && asmgen.zeropage.available() > 0) {
+                if(length>=16) {
-                    // allocate index var on ZP
+                    // allocate index var on ZP if possible
-                    val zpAddr = asmgen.zeropage.allocate(indexVar, DataType.UBYTE, stmt.position, asmgen.errors)
+                    val result = zeropage.allocate(listOf(indexVar), DataType.UBYTE, null, stmt.position, asmgen.errors)
-                    asmgen.out("""$indexVar = $zpAddr  ; auto zp UBYTE""")
+                    result.fold(
+                        success = { (address,_)-> asmgen.out("""$indexVar = $address  ; auto zp UBYTE""") },
+                        failure = { asmgen.out("$indexVar    .byte  0") }
+                    )
                 } else {
-                    asmgen.out("""
+                    asmgen.out("$indexVar    .byte  0")
-$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 indexVar = program.makeLabel("for_index")
                 val loopvarName = asmgen.asmVariableName(stmt.loopVar)
                 asmgen.out("""
                     ldy  #0
@@ -345,13 +326,15 @@ $loopLabel          sty  $indexVar
                         bne  $loopLabel
                         beq  $endLabel""")
                 }
-                if(length>=16 && asmgen.zeropage.available() > 0) {
+                if(length>=16) {
-                    // allocate index var on ZP
+                    // allocate index var on ZP if possible
-                    val zpAddr = asmgen.zeropage.allocate(indexVar, DataType.UBYTE, stmt.position, asmgen.errors)
+                    val result = zeropage.allocate(listOf(indexVar), DataType.UBYTE, null, stmt.position, asmgen.errors)
-                    asmgen.out("""$indexVar = $zpAddr  ; auto zp UBYTE""")
+                    result.fold(
+                        success = { (address,_)-> asmgen.out("""$indexVar = $address  ; auto zp UBYTE""") },
+                        failure = { asmgen.out("$indexVar    .byte  0") }
+                    )
                 } else {
-                    asmgen.out("""
+                    asmgen.out("$indexVar    .byte  0")
-$indexVar           .byte  0""")
                 }
                 asmgen.out(endLabel)
             }
@@ -376,8 +359,8 @@ $indexVar           .byte  0""")
         }
 
         // not one of the easy cases, generate more complex code...
-        val loopLabel = asmgen.makeLabel("for_loop")
+        val loopLabel = program.makeLabel("for_loop")
-        val endLabel = asmgen.makeLabel("for_end")
+        val endLabel = program.makeLabel("for_end")
         asmgen.loopEndLabels.push(endLabel)
         when(iterableDt) {
             DataType.ARRAY_B, DataType.ARRAY_UB -> {
@@ -393,7 +376,7 @@ $loopLabel""")
                         throw AssemblyError("step 0, 1 and -1 should have been handled specifically  $stmt")
                     }
                     2 -> {
-                        if(range.last==255) {
+                        if(range.last==255 || range.last==254) {
                             asmgen.out("""
                                 inc  $varname
                                 beq  $endLabel
@@ -401,34 +384,34 @@ $loopLabel""")
                                 bne  $loopLabel""")
                         } else {
                             asmgen.out("""
+                                inc  $varname
+                                inc  $varname
                                 lda  $varname
-                                cmp  #${range.last}
+                                cmp  #${range.last+2}
-                                beq  $endLabel
+                                bne  $loopLabel""")
-                                inc  $varname
-                                inc  $varname
-                                jmp  $loopLabel""")
                         }
                     }
                     -2 -> {
                         when (range.last) {
-                            0 -> asmgen.out("""
+                            0 -> {
+                                asmgen.out("""
                                     lda  $varname
                                     beq  $endLabel
                                     dec  $varname
-                                dec  $varname
+                                    dec  $varname""")
-                                jmp  $loopLabel""")
+                                asmgen.jmp(loopLabel)
+                            }
                             1 -> asmgen.out("""
                                     dec  $varname
                                     beq  $endLabel
                                     dec  $varname
                                     bne  $loopLabel""")
                             else -> asmgen.out("""
+                                    dec  $varname
+                                    dec  $varname
                                     lda  $varname
-                                cmp  #${range.last}
+                                    cmp  #${range.last-2}
-                                beq  $endLabel
+                                    bne  $loopLabel""")
-                                dec  $varname
-                                dec  $varname
-                                jmp  $loopLabel""")
                         }
                     }
                     else -> {
@@ -439,8 +422,8 @@ $loopLabel""")
                             beq  $endLabel
                             clc
                             adc  #${range.step}
-                            sta  $varname
+                            sta  $varname""")
-                            jmp  $loopLabel""")
+                        asmgen.jmp(loopLabel)
                     }
                 }
                 asmgen.out(endLabel)
@@ -476,9 +459,9 @@ $loopLabel""")
                             sta  $varname
                             lda  $varname+1
                             adc  #>${range.step}
-                            sta  $varname+1
+                            sta  $varname+1""")
-                            jmp  $loopLabel
+                        asmgen.jmp(loopLabel)
-$endLabel""")
+                        asmgen.out(endLabel)
                     }
                 }
             }
@@ -488,8 +471,8 @@ $endLabel""")
     }
 
     private fun translateForSimpleByteRangeAsc(stmt: ForLoop, range: IntProgression) {
-        val loopLabel = asmgen.makeLabel("for_loop")
+        val loopLabel = program.makeLabel("for_loop")
-        val endLabel = asmgen.makeLabel("for_end")
+        val endLabel = program.makeLabel("for_end")
         asmgen.loopEndLabels.push(endLabel)
         val varname = asmgen.asmVariableName(stmt.loopVar)
         asmgen.out("""
@@ -504,19 +487,18 @@ $loopLabel""")
 $endLabel""")
         } else {
             asmgen.out("""
-                lda  $varname
-                cmp  #${range.last}
-                beq  $endLabel
                 inc  $varname
-                jmp  $loopLabel
+                lda  $varname
+                cmp  #${range.last+1}
+                bne  $loopLabel
 $endLabel""")
         }
         asmgen.loopEndLabels.pop()
     }
 
     private fun translateForSimpleByteRangeDesc(stmt: ForLoop, range: IntProgression) {
-        val loopLabel = asmgen.makeLabel("for_loop")
+        val loopLabel = program.makeLabel("for_loop")
-        val endLabel = asmgen.makeLabel("for_end")
+        val endLabel = program.makeLabel("for_end")
         asmgen.loopEndLabels.push(endLabel)
         val varname = asmgen.asmVariableName(stmt.loopVar)
         asmgen.out("""
@@ -529,23 +511,22 @@ $loopLabel""")
                 asmgen.out("""
                     lda  $varname
                     beq  $endLabel
-                    dec  $varname
+                    dec  $varname""")
-                    jmp  $loopLabel
+                asmgen.jmp(loopLabel)
-$endLabel""")
+                asmgen.out(endLabel)
             }
             1 -> {
                 asmgen.out("""
                     dec  $varname
-                    jmp  $loopLabel
+                    bne  $loopLabel
 $endLabel""")
             }
             else -> {
                 asmgen.out("""
-                    lda  $varname
-                    cmp  #${range.last}
-                    beq  $endLabel
                     dec  $varname
-                    jmp  $loopLabel
+                    lda  $varname
+                    cmp  #${range.last-1}
+                    bne  $loopLabel
 $endLabel""")
             }
         }
@@ -553,8 +534,8 @@ $endLabel""")
     }
 
     private fun translateForSimpleWordRangeAsc(stmt: ForLoop, range: IntProgression) {
-        val loopLabel = asmgen.makeLabel("for_loop")
+        val loopLabel = program.makeLabel("for_loop")
-        val endLabel = asmgen.makeLabel("for_end")
+        val endLabel = program.makeLabel("for_end")
         asmgen.loopEndLabels.push(endLabel)
         val varname = asmgen.asmVariableName(stmt.loopVar)
         asmgen.out("""
@@ -570,19 +551,18 @@ $loopLabel""")
             bne  +
             lda  $varname+1
             cmp  #>${range.last}
-            bne  +
             beq  $endLabel
 +           inc  $varname
             bne  $loopLabel
-            inc  $varname+1
+            inc  $varname+1""")
-            jmp  $loopLabel
+        asmgen.jmp(loopLabel)
-$endLabel""")
+        asmgen.out(endLabel)
         asmgen.loopEndLabels.pop()
     }
 
     private fun translateForSimpleWordRangeDesc(stmt: ForLoop, range: IntProgression) {
-        val loopLabel = asmgen.makeLabel("for_loop")
+        val loopLabel = program.makeLabel("for_loop")
-        val endLabel = asmgen.makeLabel("for_end")
+        val endLabel = program.makeLabel("for_end")
         asmgen.loopEndLabels.push(endLabel)
         val varname = asmgen.asmVariableName(stmt.loopVar)
         asmgen.out("""
@@ -598,21 +578,20 @@ $loopLabel""")
             bne  +
             lda  $varname+1
             cmp  #>${range.last}
-            bne  +
             beq  $endLabel
 +           lda  $varname
             bne  +
             dec  $varname+1
-+           dec  $varname
++           dec  $varname""")
-            jmp  $loopLabel
+        asmgen.jmp(loopLabel)
-$endLabel""")
+        asmgen.out(endLabel)
         asmgen.loopEndLabels.pop()
     }
 
-    private fun assignLoopvar(stmt: ForLoop, range: RangeExpr) {
+    private fun assignLoopvar(stmt: ForLoop, range: RangeExpression) =
-        val target = AsmAssignTarget(TargetStorageKind.VARIABLE, program, asmgen, stmt.loopVarDt(program).typeOrElse(DataType.STRUCT), stmt.definingSubroutine(), variableAsmName=asmgen.asmVariableName(stmt.loopVar))
+        asmgen.assignExpressionToVariable(
-        val src = AsmAssignSource.fromAstSource(range.from, program, asmgen).adjustSignedUnsigned(target)
+            range.from,
-        val assign = AsmAssignment(src, target, false, range.position)
+            asmgen.asmVariableName(stmt.loopVar),
-        asmgen.translateNormalAssignment(assign)
+            stmt.loopVarDt(program).getOrElse { throw AssemblyError("unknown dt") },
-    }
+            stmt.definingSubroutine)
 }

codeGenCpu6502/src/prog8/codegen/cpu6502/FunctionCallAsmGen.kt

@@ -0,0 +1,250 @@
+package prog8.codegen.cpu6502
+
+import prog8.ast.IFunctionCall
+import prog8.ast.Node
+import prog8.ast.Program
+import prog8.ast.expressions.AddressOf
+import prog8.ast.expressions.Expression
+import prog8.ast.expressions.IdentifierReference
+import prog8.ast.expressions.NumericLiteral
+import prog8.ast.statements.FunctionCallStatement
+import prog8.ast.statements.InlineAssembly
+import prog8.ast.statements.Subroutine
+import prog8.ast.statements.SubroutineParameter
+import prog8.code.core.*
+import prog8.codegen.cpu6502.assignment.AsmAssignSource
+import prog8.codegen.cpu6502.assignment.AsmAssignTarget
+import prog8.codegen.cpu6502.assignment.AsmAssignment
+import prog8.codegen.cpu6502.assignment.TargetStorageKind
+
+
+internal class FunctionCallAsmGen(private val program: Program, private val asmgen: AsmGen) {
+
+    internal fun translateFunctionCallStatement(stmt: FunctionCallStatement) {
+        saveXbeforeCall(stmt)
+        translateFunctionCall(stmt, false)
+        restoreXafterCall(stmt)
+        // just ignore any result values from the function call.
+    }
+
+    internal fun saveXbeforeCall(stmt: IFunctionCall) {
+        val sub = stmt.target.targetSubroutine(program) ?: throw AssemblyError("undefined subroutine ${stmt.target}")
+        if(sub.shouldSaveX()) {
+            val regSaveOnStack = sub.asmAddress==null       // rom-routines don't require registers to be saved on stack, normal subroutines do because they can contain nested calls
+            if(regSaveOnStack)
+                asmgen.saveRegisterStack(CpuRegister.X, sub.shouldKeepA().saveOnEntry)
+            else
+                asmgen.saveRegisterLocal(CpuRegister.X, (stmt as Node).definingSubroutine!!)
+        }
+    }
+
+    internal fun restoreXafterCall(stmt: IFunctionCall) {
+        val sub = stmt.target.targetSubroutine(program) ?: throw AssemblyError("undefined subroutine ${stmt.target}")
+        if(sub.shouldSaveX()) {
+            val regSaveOnStack = sub.asmAddress==null       // rom-routines don't require registers to be saved on stack, normal subroutines do because they can contain nested calls
+            if(regSaveOnStack)
+                asmgen.restoreRegisterStack(CpuRegister.X, sub.shouldKeepA().saveOnReturn)
+            else
+                asmgen.restoreRegisterLocal(CpuRegister.X)
+        }
+    }
+
+    internal fun optimizeIntArgsViaRegisters(sub: Subroutine) =
+        (sub.parameters.size==1 && sub.parameters[0].type in IntegerDatatypes)
+                || (sub.parameters.size==2 && sub.parameters[0].type in ByteDatatypes && sub.parameters[1].type in ByteDatatypes)
+
+    internal fun translateFunctionCall(call: IFunctionCall, isExpression: Boolean) {
+        // Output only the code to set up the parameters and perform the actual call
+        // NOTE: does NOT output the code to deal with the result values!
+        // NOTE: does NOT output code to save/restore the X register for this call! Every caller should deal with this in their own way!!
+        //       (you can use subroutine.shouldSaveX() and saveX()/restoreX() routines as a help for this)
+
+        val sub = call.target.targetSubroutine(program) ?: throw AssemblyError("undefined subroutine ${call.target}")
+        val subAsmName = asmgen.asmSymbolName(call.target)
+
+        if(sub.isAsmSubroutine) {
+            argumentsViaRegisters(sub, call)
+            if (sub.inline && asmgen.options.optimize) {
+                // inline the subroutine.
+                // we do this by copying the subroutine's statements at the call site.
+                // NOTE: *if* there is a return statement, it will be the only one, and the very last statement of the subroutine
+                // (this condition has been enforced by an ast check earlier)
+                asmgen.out("  \t; inlined routine follows: ${sub.name}")
+                sub.statements.forEach { asmgen.translate(it as InlineAssembly) }
+                asmgen.out("  \t; inlined routine end: ${sub.name}")
+            } else {
+                asmgen.out("  jsr  $subAsmName")
+            }
+        }
+        else {
+            if(sub.inline)
+                throw AssemblyError("can only reliably inline asmsub routines at this time")
+
+            if(optimizeIntArgsViaRegisters(sub)) {
+                if(sub.parameters.size==1) {
+                    val register = if (sub.parameters[0].type in ByteDatatypes) RegisterOrPair.A else RegisterOrPair.AY
+                    argumentViaRegister(sub, IndexedValue(0, sub.parameters[0]), call.args[0], register)
+                } else {
+                    // 2 byte params, second in Y, first in A
+                    argumentViaRegister(sub, IndexedValue(0, sub.parameters[0]), call.args[0], RegisterOrPair.A)
+                    if(asmgen.needAsaveForExpr(call.args[1]))
+                        asmgen.out("  pha")
+                    argumentViaRegister(sub, IndexedValue(1, sub.parameters[1]), call.args[1], RegisterOrPair.Y)
+                    if(asmgen.needAsaveForExpr(call.args[1]))
+                        asmgen.out("  pla")
+                }
+            } else {
+                // arguments via variables
+                for(arg in sub.parameters.withIndex().zip(call.args))
+                    argumentViaVariable(sub, arg.first.value, arg.second)
+            }
+            asmgen.out("  jsr  $subAsmName")
+        }
+
+        // remember: dealing with the X register and/or dealing with return values is the responsibility of the caller
+    }
+
+    private fun argumentsViaRegisters(sub: Subroutine, call: IFunctionCall) {
+        if(sub.parameters.size==1) {
+            argumentViaRegister(sub, IndexedValue(0, sub.parameters.single()), call.args[0])
+        } else {
+            if(asmsub6502ArgsHaveRegisterClobberRisk(call.args, sub.asmParameterRegisters)) {
+                registerArgsViaCpuStackEvaluation(call, sub)
+            } else {
+                asmsub6502ArgsEvalOrder(sub).forEach {
+                    val param = sub.parameters[it]
+                    val arg = call.args[it]
+                    argumentViaRegister(sub, IndexedValue(it, param), arg)
+                }
+            }
+        }
+    }
+
+    private fun registerArgsViaCpuStackEvaluation(call: IFunctionCall, callee: 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.
+
+        require(callee.isAsmSubroutine)
+        if(callee.parameters.isEmpty())
+            return
+
+        // use the cpu hardware stack as intermediate storage for the arguments.
+        val argOrder = asmsub6502ArgsEvalOrder(callee)
+        argOrder.reversed().forEach {
+            asmgen.pushCpuStack(callee.parameters[it].type, call.args[it])
+        }
+        argOrder.forEach {
+            val param = callee.parameters[it]
+            val targetVar = callee.searchParameter(param.name)!!
+            asmgen.popCpuStack(param.type, targetVar, (call as Node).definingSubroutine)
+        }
+    }
+
+    private fun argumentViaVariable(sub: Subroutine, parameter: SubroutineParameter, value: Expression) {
+        // pass parameter via a regular variable (not via registers)
+        val valueIDt = value.inferType(program)
+        val valueDt = valueIDt.getOrElse { throw AssemblyError("unknown dt") }
+        if(!isArgumentTypeCompatible(valueDt, parameter.type))
+            throw AssemblyError("argument type incompatible")
+
+        val varName = asmgen.asmVariableName(sub.scopedName + parameter.name)
+        asmgen.assignExpressionToVariable(value, varName, parameter.type, sub)
+    }
+
+    private fun argumentViaRegister(sub: Subroutine, parameter: IndexedValue<SubroutineParameter>, value: Expression, registerOverride: RegisterOrPair? = null) {
+        // pass argument via a register parameter
+        val valueIDt = value.inferType(program)
+        val valueDt = valueIDt.getOrElse { throw AssemblyError("unknown dt") }
+        if(!isArgumentTypeCompatible(valueDt, parameter.value.type))
+            throw AssemblyError("argument type incompatible")
+
+        val paramRegister = if(registerOverride==null) sub.asmParameterRegisters[parameter.index] else RegisterOrStatusflag(registerOverride, null)
+        val statusflag = paramRegister.statusflag
+        val register = paramRegister.registerOrPair
+        val requiredDt = parameter.value.type
+        if(requiredDt!=valueDt) {
+            if(valueDt largerThan requiredDt)
+                throw AssemblyError("can only convert byte values to word param types")
+        }
+        if (statusflag!=null) {
+            if(requiredDt!=valueDt)
+                throw AssemblyError("for statusflag, byte value is required")
+            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 NumericLiteral -> {
+                        val carrySet = value.number.toInt() != 0
+                        asmgen.out(if(carrySet) "  sec" else "  clc")
+                    }
+                    is IdentifierReference -> {
+                        val sourceName = asmgen.asmVariableName(value)
+                        asmgen.out("""
+                            pha
+                            clc
+                            lda  $sourceName
+                            beq  +
+                            sec  
++                           pla""")
+                    }
+                    else -> {
+                        asmgen.assignExpressionToRegister(value, RegisterOrPair.A)
+                        asmgen.out("""
+                            beq  +
+                            sec
+                            bcs  ++
++                           clc
++""")
+                    }
+                }
+            } else throw AssemblyError("can only use Carry as status flag parameter")
+        }
+        else {
+            // via register or register pair
+            register!!
+            if(requiredDt largerThan valueDt) {
+                // we need to sign extend the source, do this via temporary word variable
+                asmgen.assignExpressionToVariable(value, "P8ZP_SCRATCH_W1", DataType.UBYTE, sub)
+                asmgen.signExtendVariableLsb("P8ZP_SCRATCH_W1", valueDt)
+                asmgen.assignVariableToRegister("P8ZP_SCRATCH_W1", register)
+            } else {
+                val target: AsmAssignTarget =
+                    if(parameter.value.type in ByteDatatypes && (register==RegisterOrPair.AX || register == RegisterOrPair.AY || register==RegisterOrPair.XY || register in Cx16VirtualRegisters))
+                        AsmAssignTarget(TargetStorageKind.REGISTER, asmgen, parameter.value.type, sub, register = register)
+                    else {
+                        val signed = parameter.value.type == DataType.BYTE || parameter.value.type == DataType.WORD
+                        AsmAssignTarget.fromRegisters(register, signed, sub, asmgen)
+                    }
+                val src = if(valueDt in PassByReferenceDatatypes) {
+                    if(value is IdentifierReference) {
+                        val addr = AddressOf(value, Position.DUMMY)
+                        AsmAssignSource.fromAstSource(addr, program, asmgen).adjustSignedUnsigned(target)
+                    } else {
+                        AsmAssignSource.fromAstSource(value, program, asmgen).adjustSignedUnsigned(target)
+                    }
+                } else {
+                    AsmAssignSource.fromAstSource(value, program, asmgen).adjustSignedUnsigned(target)
+                }
+                asmgen.translateNormalAssignment(AsmAssignment(src, target, false, program.memsizer, 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
+    }
+}

codeGenCpu6502/src/prog8/codegen/cpu6502/PostIncrDecrAsmGen.kt

@@ -1,12 +1,10 @@
-package prog8.compiler.target.c64.codegen
+package prog8.codegen.cpu6502
 
 import prog8.ast.Program
-import prog8.ast.base.*
 import prog8.ast.expressions.IdentifierReference
-import prog8.ast.expressions.NumericLiteralValue
+import prog8.ast.expressions.NumericLiteral
 import prog8.ast.statements.PostIncrDecr
-import prog8.compiler.AssemblyError
+import prog8.code.core.*
-import prog8.compiler.toHex
 
 
 internal class PostIncrDecrAsmGen(private val program: Program, private val asmgen: AsmGen) {
@@ -15,11 +13,11 @@ internal class PostIncrDecrAsmGen(private val program: Program, private val asmg
         val targetIdent = stmt.target.identifier
         val targetMemory = stmt.target.memoryAddress
         val targetArrayIdx = stmt.target.arrayindexed
-        val scope = stmt.definingSubroutine()
+        val scope = stmt.definingSubroutine
         when {
             targetIdent!=null -> {
                 val what = asmgen.asmVariableName(targetIdent)
-                when (stmt.target.inferType(program, stmt).typeOrElse(DataType.STRUCT)) {
+                when (stmt.target.inferType(program).getOr(DataType.UNDEFINED)) {
                     in ByteDatatypes -> asmgen.out(if (incr) "  inc  $what" else "  dec  $what")
                     in WordDatatypes -> {
                         if(incr)
@@ -41,7 +39,7 @@ internal class PostIncrDecrAsmGen(private val program: Program, private val asmg
             }
             targetMemory!=null -> {
                 when (val addressExpr = targetMemory.addressExpression) {
-                    is NumericLiteralValue -> {
+                    is NumericLiteral -> {
                         val what = addressExpr.number.toHex()
                         asmgen.out(if(incr) "  inc  $what" else "  dec  $what")
                     }
@@ -54,14 +52,8 @@ internal class PostIncrDecrAsmGen(private val program: Program, private val asmg
                             asmgen.out("+\tdec  ${'$'}ffff\t; modified")
                     }
                     else -> {
-                        asmgen.translateExpression(addressExpr)
+                        asmgen.assignExpressionToRegister(addressExpr, RegisterOrPair.AY)
-                        asmgen.out("""
+                        asmgen.out("  sta  (+) + 1 |  sty  (+) + 2")
-                            inx
-                            lda  P8ESTACK_LO,x
-                            sta  (+) + 1
-                            lda  P8ESTACK_HI,x
-                            sta  (+) + 2
-                        """)
                         if(incr)
                             asmgen.out("+\tinc  ${'$'}ffff\t; modified")
                         else
@@ -71,9 +63,10 @@ internal class PostIncrDecrAsmGen(private val program: Program, private val asmg
             }
             targetArrayIdx!=null -> {
                 val asmArrayvarname = asmgen.asmVariableName(targetArrayIdx.arrayvar)
-                val elementDt = targetArrayIdx.inferType(program).typeOrElse(DataType.STRUCT)
+                val elementDt = targetArrayIdx.inferType(program).getOr(DataType.UNDEFINED)
-                if(targetArrayIdx.indexer.indexNum!=null) {
+                val constIndex = targetArrayIdx.indexer.constIndex()
-                    val indexValue = targetArrayIdx.indexer.constIndex()!! * elementDt.memorySize()
+                if(constIndex!=null) {
+                    val indexValue = constIndex * program.memsizer.memorySize(elementDt)
                     when(elementDt) {
                         in ByteDatatypes -> asmgen.out(if (incr) "  inc  $asmArrayvarname+$indexValue" else "  dec  $asmArrayvarname+$indexValue")
                         in WordDatatypes -> {
@@ -88,7 +81,7 @@ internal class PostIncrDecrAsmGen(private val program: Program, private val asmg
 """)
                         }
                         DataType.FLOAT -> {
-                            asmgen.out("  lda  #<$asmArrayvarname+$indexValue |  ldy  #>$asmArrayvarname+$indexValue")
+                            asmgen.out("  lda  #<($asmArrayvarname+$indexValue) |  ldy  #>($asmArrayvarname+$indexValue)")
                             asmgen.out(if(incr) "  jsr  floats.inc_var_f" else "  jsr  floats.dec_var_f")
                         }
                         else -> throw AssemblyError("need numeric type")
@@ -97,7 +90,7 @@ internal class PostIncrDecrAsmGen(private val program: Program, private val asmg
                 else
                 {
                     asmgen.loadScaledArrayIndexIntoRegister(targetArrayIdx, elementDt, CpuRegister.A)
-                    asmgen.saveRegister(CpuRegister.X, false, scope)
+                    asmgen.saveRegisterLocal(CpuRegister.X, scope!!)
                     asmgen.out("  tax")
                     when(elementDt) {
                         in ByteDatatypes -> {
@@ -111,7 +104,7 @@ internal class PostIncrDecrAsmGen(private val program: Program, private val asmg
     lda  $asmArrayvarname,x
     bne  +
     dec  $asmArrayvarname+1,x
-+       dec  $asmArrayvarname 
++       dec  $asmArrayvarname,x 
 """)
                         }
                         DataType.FLOAT -> {
@@ -125,7 +118,7 @@ internal class PostIncrDecrAsmGen(private val program: Program, private val asmg
                         }
                         else -> throw AssemblyError("weird array elt dt")
                     }
-                    asmgen.restoreRegister(CpuRegister.X, false)
+                    asmgen.restoreRegisterLocal(CpuRegister.X)
                 }
             }
         }

codeGenCpu6502/src/prog8/codegen/cpu6502/ProgramAndVarsGen.kt

@@ -0,0 +1,673 @@
+package prog8.codegen.cpu6502
+
+import prog8.ast.Program
+import prog8.ast.statements.*
+import prog8.code.*
+import prog8.code.core.*
+import prog8.codegen.cpu6502.assignment.AsmAssignTarget
+import prog8.codegen.cpu6502.assignment.TargetStorageKind
+import prog8.compiler.CallGraph
+import java.time.LocalDate
+import java.time.LocalDateTime
+import kotlin.math.absoluteValue
+
+/**
+ * Generates the main parts of the program:
+ *  - entry/exit code
+ *  - initialization routines
+ *  - blocks
+ *  - subroutines
+ *  - all variables (note: VarDecl ast nodes are *NOT* used anymore for this! now uses IVariablesAndConsts data tables!)
+ */
+internal class ProgramAndVarsGen(
+    val program: Program,
+    val options: CompilationOptions,
+    val errors: IErrorReporter,
+    private val symboltable: SymbolTable,
+    private val functioncallAsmGen: FunctionCallAsmGen,
+    private val asmgen: AsmGen,
+    private val allocator: VariableAllocator,
+    private val zeropage: Zeropage
+) {
+    private val compTarget = options.compTarget
+    private val callGraph = CallGraph(program, true)
+    private val blockVariableInitializers = program.allBlocks.associateWith { it.statements.filterIsInstance<Assignment>() }
+
+    internal fun generate() {
+        val allInitializers = blockVariableInitializers.asSequence().flatMap { it.value }
+        require(allInitializers.all { it.origin==AssignmentOrigin.VARINIT }) {"all block-level assignments must be a variable initializer"}
+
+        header()
+        val allBlocks = program.allBlocks
+        if(allBlocks.first().name != "main")
+            throw AssemblyError("first block should be 'main'")
+
+        if(errors.noErrors())  {
+            program.allBlocks.forEach { block2asm(it) }
+
+            // the global list of all floating point constants for the whole program
+            asmgen.out("; global float constants")
+            for (flt in allocator.globalFloatConsts) {
+                val floatFill = compTarget.machine.getFloatAsmBytes(flt.key)
+                val floatvalue = flt.key
+                asmgen.out("${flt.value}\t.byte  $floatFill  ; float $floatvalue")
+            }
+
+            memorySlabs()
+            footer()
+        }
+    }
+
+    private fun header() {
+        val ourName = this.javaClass.name
+        val cpu = when(compTarget.machine.cpu) {
+            CpuType.CPU6502 -> "6502"
+            CpuType.CPU65c02 -> "w65c02"
+            else -> "unsupported"
+        }
+
+        asmgen.out("; $cpu assembly code for '${program.name}'")
+        asmgen.out("; generated by $ourName on ${LocalDateTime.now().withNano(0)}")
+        asmgen.out("; assembler syntax is for the 64tasm cross-assembler")
+        asmgen.out("; output options: output=${options.output} launcher=${options.launcher} zp=${options.zeropage}")
+        asmgen.out("")
+        asmgen.out(".cpu  '$cpu'\n.enc  'none'\n")
+
+        // the global prog8 variables needed
+        val zp = zeropage
+        asmgen.out("P8ZP_SCRATCH_B1 = ${zp.SCRATCH_B1}")
+        asmgen.out("P8ZP_SCRATCH_REG = ${zp.SCRATCH_REG}")
+        asmgen.out("P8ZP_SCRATCH_W1 = ${zp.SCRATCH_W1}    ; word")
+        asmgen.out("P8ZP_SCRATCH_W2 = ${zp.SCRATCH_W2}    ; word")
+        asmgen.out(".weak")   // hack to allow user to override the following two with command line redefinition (however, just use '-esa' command line option instead!)
+        asmgen.out("P8ESTACK_LO = ${compTarget.machine.ESTACK_LO.toHex()}")
+        asmgen.out("P8ESTACK_HI = ${compTarget.machine.ESTACK_HI.toHex()}")
+        asmgen.out(".endweak")
+
+        if(options.symbolDefs.isNotEmpty()) {
+            asmgen.out("; -- user supplied symbols on the command line")
+            for((name, value) in options.symbolDefs) {
+                asmgen.out("$name = $value")
+            }
+        }
+
+        when(options.output) {
+            OutputType.RAW -> {
+                asmgen.out("; ---- raw assembler program ----")
+                asmgen.out("* = ${options.loadAddress.toHex()}\n")
+            }
+            OutputType.PRG -> {
+                when(options.launcher) {
+                    CbmPrgLauncherType.BASIC -> {
+                        if (options.loadAddress != options.compTarget.machine.PROGRAM_LOAD_ADDRESS) {
+                            errors.err("BASIC output must have load address ${options.compTarget.machine.PROGRAM_LOAD_ADDRESS.toHex()}", program.toplevelModule.position)
+                        }
+                        asmgen.out("; ---- basic program with sys call ----")
+                        asmgen.out("* = ${options.loadAddress.toHex()}")
+                        val year = LocalDate.now().year
+                        asmgen.out("  .word  (+), $year")
+                        asmgen.out("  .null  $9e, format(' %d ', prog8_entrypoint), $3a, $8f, ' prog8'")
+                        asmgen.out("+\t.word  0")
+                        asmgen.out("prog8_entrypoint\t; assembly code starts here\n")
+                        if(!options.noSysInit)
+                            asmgen.out("  jsr  ${compTarget.name}.init_system")
+                        asmgen.out("  jsr  ${compTarget.name}.init_system_phase2")
+                    }
+                    CbmPrgLauncherType.NONE -> {
+                        asmgen.out("; ---- program without basic sys call ----")
+                        asmgen.out("* = ${options.loadAddress.toHex()}\n")
+                        if(!options.noSysInit)
+                            asmgen.out("  jsr  ${compTarget.name}.init_system")
+                        asmgen.out("  jsr  ${compTarget.name}.init_system_phase2")
+                    }
+                }
+            }
+            OutputType.XEX -> {
+                asmgen.out("; ---- atari xex program ----")
+                asmgen.out("* = ${options.loadAddress.toHex()}\n")
+                if(!options.noSysInit)
+                    asmgen.out("  jsr  ${compTarget.name}.init_system")
+                asmgen.out("  jsr  ${compTarget.name}.init_system_phase2")
+            }
+        }
+
+        if(options.zeropage !in arrayOf(ZeropageType.BASICSAFE, ZeropageType.DONTUSE)) {
+            asmgen.out("""
+                ; zeropage is clobbered so we need to reset the machine at exit
+                lda  #>sys.reset_system
+                pha
+                lda  #<sys.reset_system
+                pha""")
+        }
+
+        // make sure that on the cx16 and c64, basic rom is banked in again when we exit the program
+        when(compTarget.name) {
+            "cx16" -> {
+                if(options.floats)
+                    asmgen.out("  lda  #4 |  sta  $01")    // to use floats, make sure Basic rom is banked in
+                asmgen.out("  jsr  main.start")
+                asmgen.out("  jmp  ${compTarget.name}.cleanup_at_exit")
+            }
+            "c64" -> {
+                asmgen.out("  jsr  main.start |  lda  #31 |  sta  $01")
+                if(!options.noSysInit)
+                    asmgen.out("  jmp  ${compTarget.name}.cleanup_at_exit")
+                else
+                    asmgen.out("  rts")
+            }
+            "c128" -> {
+                asmgen.out("  jsr  main.start")
+                // TODO c128: how to bank basic+kernal back in?
+                if(!options.noSysInit)
+                    asmgen.out("  jmp  ${compTarget.name}.cleanup_at_exit")
+                else
+                    asmgen.out("  rts")
+            }
+            else -> asmgen.jmp("main.start")
+        }
+    }
+
+    private fun memorySlabs() {
+        asmgen.out("; memory slabs")
+        asmgen.out("prog8_slabs\t.block")
+        for(slab in symboltable.allMemorySlabs) {
+            if(slab.align>1u)
+                asmgen.out("\t.align  ${slab.align.toHex()}")
+            asmgen.out("${slab.name}\t.fill  ${slab.size}")
+        }
+        asmgen.out("\t.bend")
+    }
+
+    private fun footer() {
+        // program end
+        asmgen.out("prog8_program_end\t; end of program label for progend()")
+    }
+
+    private fun block2asm(block: Block) {
+        asmgen.out("")
+        asmgen.out("; ---- block: '${block.name}' ----")
+        if(block.address!=null)
+            asmgen.out("* = ${block.address!!.toHex()}")
+        else {
+            if("align_word" in block.options())
+                asmgen.out("\t.align 2")
+            else if("align_page" in block.options())
+                asmgen.out("\t.align $100")
+        }
+
+        asmgen.out("${block.name}\t" + (if("force_output" in block.options()) ".block\n" else ".proc\n"))
+        asmgen.outputSourceLine(block)
+
+        createBlockVariables(block)
+        asmsubs2asm(block.statements)
+
+        asmgen.out("")
+        asmgen.out("; subroutines in this block")
+
+        // First translate regular statements, and then put the subroutines at the end.
+        // (regular statements = everything except the initialization assignments;
+        // these will be part of the prog8_init_vars init routine generated below)
+        val initializers = blockVariableInitializers.getValue(block)
+        val statements = block.statements.filterNot { it in initializers }
+        val (subroutine, stmts) = statements.partition { it is Subroutine }
+        stmts.forEach { asmgen.translate(it) }
+        subroutine.forEach { asmgen.translate(it) }
+
+        if(!options.dontReinitGlobals) {
+            // generate subroutine to initialize block-level (global) variables
+            if (initializers.isNotEmpty()) {
+                asmgen.out("prog8_init_vars\t.block\n")
+                initializers.forEach { assign -> asmgen.translate(assign) }
+                asmgen.out("  rts\n  .bend")
+            }
+        }
+
+        asmgen.out(if("force_output" in block.options()) "\n\t.bend\n" else "\n\t.pend\n")
+    }
+
+    private fun getVars(scope: StNode): Map<String, StNode> =
+        scope.children.filter { it.value.type in arrayOf(StNodeType.STATICVAR, StNodeType.CONSTANT, StNodeType.MEMVAR) }
+
+    private fun createBlockVariables(block: Block) {
+        val scope = symboltable.lookupOrElse(block.name) { throw AssemblyError("lookup") }
+        require(scope.type==StNodeType.BLOCK)
+        val varsInBlock = getVars(scope)
+
+        // Zeropage Variables
+        val varnames = varsInBlock.filter { it.value.type==StNodeType.STATICVAR }.map { it.value.scopedName }.toSet()
+        zeropagevars2asm(varnames)
+
+        // MemDefs and Consts
+        val mvs = varsInBlock
+            .filter { it.value.type==StNodeType.MEMVAR }
+            .map { it.value as StMemVar }
+        val consts = varsInBlock
+            .filter { it.value.type==StNodeType.CONSTANT }
+            .map { it.value as StConstant }
+        memdefsAndConsts2asm(mvs, consts)
+
+        // normal statically allocated variables
+        val variables = varsInBlock
+            .filter { it.value.type==StNodeType.STATICVAR && !allocator.isZpVar(it.value.scopedName) }
+            .map { it.value as StStaticVariable }
+        nonZpVariables2asm(variables)
+    }
+
+    internal fun translateSubroutine(sub: Subroutine) {
+        var onlyVariables = false
+
+        if(sub.inline) {
+            if(options.optimize) {
+                if(sub.isAsmSubroutine || callGraph.unused(sub))
+                    return
+
+                // from an inlined subroutine only the local variables are generated,
+                // all other code statements are omitted in the subroutine itself
+                // (they've been inlined at the call site, remember?)
+                onlyVariables = true
+            }
+        }
+
+        asmgen.out("")
+
+        val asmStartScope: String
+        val asmEndScope: String
+        if(sub.definingBlock.options().contains("force_output")) {
+            asmStartScope = ".block"
+            asmEndScope = ".bend"
+        } else {
+            asmStartScope = ".proc"
+            asmEndScope = ".pend"
+        }
+
+        if(sub.isAsmSubroutine) {
+            if(sub.asmAddress!=null)
+                return  // already done at the memvars section
+
+            // asmsub with most likely just an inline asm in it
+            asmgen.out("${sub.name}\t$asmStartScope")
+            sub.statements.forEach { asmgen.translate(it) }
+            asmgen.out("  $asmEndScope\n")
+        } else {
+            // regular subroutine
+            asmgen.out("${sub.name}\t$asmStartScope")
+
+            val scope = symboltable.lookupOrElse(sub.scopedName) { throw AssemblyError("lookup") }
+            require(scope.type==StNodeType.SUBROUTINE)
+            val varsInSubroutine = getVars(scope)
+
+            // Zeropage Variables
+            val varnames = varsInSubroutine.filter { it.value.type==StNodeType.STATICVAR }.map { it.value.scopedName }.toSet()
+            zeropagevars2asm(varnames)
+
+            // MemDefs and Consts
+            val mvs = varsInSubroutine
+                .filter { it.value.type==StNodeType.MEMVAR }
+                .map { it.value as StMemVar }
+            val consts = varsInSubroutine
+                .filter { it.value.type==StNodeType.CONSTANT }
+                .map { it.value as StConstant }
+            memdefsAndConsts2asm(mvs, consts)
+
+            asmsubs2asm(sub.statements)
+
+            // the main.start subroutine is the program's entrypoint and should perform some initialization logic
+            if(sub.name=="start" && sub.definingBlock.name=="main")
+                entrypointInitialization()
+
+            if(functioncallAsmGen.optimizeIntArgsViaRegisters(sub)) {
+                asmgen.out("; simple int arg(s) passed via register(s)")
+                if(sub.parameters.size==1) {
+                    val dt = sub.parameters[0].type
+                    val target = AsmAssignTarget(TargetStorageKind.VARIABLE, asmgen, dt, sub, variableAsmName = sub.parameters[0].name)
+                    if(dt in ByteDatatypes)
+                        asmgen.assignRegister(RegisterOrPair.A, target)
+                    else
+                        asmgen.assignRegister(RegisterOrPair.AY, target)
+                } else {
+                    require(sub.parameters.size==2)
+                    // 2 simple byte args, first in A, second in Y
+                    val target1 = AsmAssignTarget(TargetStorageKind.VARIABLE, asmgen, sub.parameters[0].type, sub, variableAsmName = sub.parameters[0].name)
+                    val target2 = AsmAssignTarget(TargetStorageKind.VARIABLE, asmgen, sub.parameters[1].type, sub, variableAsmName = sub.parameters[1].name)
+                    asmgen.assignRegister(RegisterOrPair.A, target1)
+                    asmgen.assignRegister(RegisterOrPair.Y, target2)
+                }
+            }
+
+            if(!onlyVariables) {
+                asmgen.out("; statements")
+                sub.statements.forEach { asmgen.translate(it) }
+            }
+
+            asmgen.out("; variables")
+            val asmGenInfo = asmgen.subroutineExtra(sub)
+            for((dt, name, addr) in asmGenInfo.extraVars) {
+                if(addr!=null)
+                    asmgen.out("$name = $addr")
+                else when(dt) {
+                    DataType.UBYTE -> asmgen.out("$name    .byte  0")
+                    DataType.UWORD -> asmgen.out("$name    .word  0")
+                    else -> throw AssemblyError("weird dt")
+                }
+            }
+            if(asmGenInfo.usedRegsaveA)      // will probably never occur
+                asmgen.out("prog8_regsaveA     .byte  0")
+            if(asmGenInfo.usedRegsaveX)
+                asmgen.out("prog8_regsaveX     .byte  0")
+            if(asmGenInfo.usedRegsaveY)
+                asmgen.out("prog8_regsaveY     .byte  0")
+            if(asmGenInfo.usedFloatEvalResultVar1)
+                asmgen.out("$subroutineFloatEvalResultVar1    .byte  0,0,0,0,0")
+            if(asmGenInfo.usedFloatEvalResultVar2)
+                asmgen.out("$subroutineFloatEvalResultVar2    .byte  0,0,0,0,0")
+
+            // normal statically allocated variables
+            val variables = varsInSubroutine
+                .filter { it.value.type==StNodeType.STATICVAR && !allocator.isZpVar(it.value.scopedName) }
+                .map { it.value as StStaticVariable }
+            nonZpVariables2asm(variables)
+
+            asmgen.out("  $asmEndScope\n")
+        }
+    }
+
+    private fun entrypointInitialization() {
+        asmgen.out("; program startup initialization")
+        asmgen.out("  cld")
+        if(!options.dontReinitGlobals) {
+            blockVariableInitializers.forEach {
+                if (it.value.isNotEmpty())
+                    asmgen.out("  jsr  ${it.key.name}.prog8_init_vars")
+            }
+        }
+
+        // string and array variables in zeropage that have initializer value, should be initialized
+        val stringVarsWithInitInZp = getZpStringVarsWithInitvalue()
+        val arrayVarsWithInitInZp = getZpArrayVarsWithInitvalue()
+        if(stringVarsWithInitInZp.isNotEmpty() || arrayVarsWithInitInZp.isNotEmpty()) {
+            asmgen.out("; zp str and array initializations")
+            stringVarsWithInitInZp.forEach {
+                val name = asmgen.asmVariableName(it.name)
+                asmgen.out("""
+                    lda  #<${name}
+                    ldy  #>${name}
+                    sta  P8ZP_SCRATCH_W1
+                    sty  P8ZP_SCRATCH_W1+1
+                    lda  #<${name}_init_value
+                    ldy  #>${name}_init_value
+                    jsr  prog8_lib.strcpy""")
+            }
+            arrayVarsWithInitInZp.forEach {
+                val size = it.alloc.size
+                val name = asmgen.asmVariableName(it.name)
+                asmgen.out("""
+                    lda  #<${name}_init_value
+                    ldy  #>${name}_init_value
+                    sta  cx16.r0L
+                    sty  cx16.r0H
+                    lda  #<${name}
+                    ldy  #>${name}
+                    sta  cx16.r1L
+                    sty  cx16.r1H
+                    lda  #<$size
+                    ldy  #>$size
+                    jsr  sys.memcopy""")
+            }
+            asmgen.out("  jmp  +")
+        }
+
+        stringVarsWithInitInZp.forEach {
+            val varname = asmgen.asmVariableName(it.name)+"_init_value"
+            outputStringvar(varname, it.value.second, it.value.first)
+        }
+
+        arrayVarsWithInitInZp.forEach {
+            val varname = asmgen.asmVariableName(it.name)+"_init_value"
+            arrayVariable2asm(varname, it.alloc.dt, it.value, null)
+        }
+
+        asmgen.out("""+       tsx
+                    stx  prog8_lib.orig_stackpointer    ; required for sys.exit()                    
+                    ldx  #255       ; init estack ptr
+                    clv
+                    clc""")
+    }
+
+    private class ZpStringWithInitial(
+        val name: List<String>,
+        val alloc: Zeropage.ZpAllocation,
+        val value: Pair<String, Encoding>
+    )
+
+    private class ZpArrayWithInitial(
+        val name: List<String>,
+        val alloc: Zeropage.ZpAllocation,
+        val value: StArray
+    )
+
+    private fun getZpStringVarsWithInitvalue(): Collection<ZpStringWithInitial> {
+        val result = mutableListOf<ZpStringWithInitial>()
+        val vars = allocator.zeropageVars.filter { it.value.dt==DataType.STR }
+        for (variable in vars) {
+            val svar = symboltable.flat.getValue(variable.key) as StStaticVariable
+            if(svar.onetimeInitializationStringValue!=null)
+                result.add(ZpStringWithInitial(variable.key, variable.value, svar.onetimeInitializationStringValue!!))
+        }
+        return result
+    }
+
+    private fun getZpArrayVarsWithInitvalue(): Collection<ZpArrayWithInitial> {
+        val result = mutableListOf<ZpArrayWithInitial>()
+        val vars = allocator.zeropageVars.filter { it.value.dt in ArrayDatatypes }
+        for (variable in vars) {
+            val svar = symboltable.flat.getValue(variable.key) as StStaticVariable
+            if(svar.onetimeInitializationArrayValue!=null)
+                result.add(ZpArrayWithInitial(variable.key, variable.value, svar.onetimeInitializationArrayValue!!))
+        }
+        return result
+    }
+
+    private fun zeropagevars2asm(varNames: Set<List<String>>) {
+        val zpVariables = allocator.zeropageVars.filter { it.key in varNames }
+        for ((scopedName, zpvar) in zpVariables) {
+            if (scopedName.size == 2 && scopedName[0] == "cx16" && scopedName[1][0] == 'r' && scopedName[1][1].isDigit())
+                continue        // The 16 virtual registers of the cx16 are not actual variables in zp, they're memory mapped
+            asmgen.out("${scopedName.last()} \t= ${zpvar.address} \t; zp ${zpvar.dt}")
+        }
+    }
+
+    private fun nonZpVariables2asm(variables: List<StStaticVariable>) {
+        asmgen.out("")
+        asmgen.out("; non-zeropage variables")
+        val (stringvars, othervars) = variables.partition { it.dt==DataType.STR }
+        stringvars.forEach {
+            outputStringvar(it.name, it.onetimeInitializationStringValue!!.second, it.onetimeInitializationStringValue!!.first)
+        }
+        othervars.sortedBy { it.type }.forEach {
+            staticVariable2asm(it)
+        }
+    }
+
+    private fun staticVariable2asm(variable: StStaticVariable) {
+        val name = variable.name
+        val initialValue: Number =
+            if(variable.onetimeInitializationNumericValue!=null) {
+                if(variable.dt== DataType.FLOAT)
+                    variable.onetimeInitializationNumericValue!!
+                else
+                    variable.onetimeInitializationNumericValue!!.toInt()
+            } else 0
+
+        when (variable.dt) {
+            DataType.UBYTE -> asmgen.out("$name\t.byte  ${initialValue.toHex()}")
+            DataType.BYTE -> asmgen.out("$name\t.char  $initialValue")
+            DataType.UWORD -> asmgen.out("$name\t.word  ${initialValue.toHex()}")
+            DataType.WORD -> asmgen.out("$name\t.sint  $initialValue")
+            DataType.FLOAT -> {
+                if(initialValue==0) {
+                    asmgen.out("$name\t.byte  0,0,0,0,0  ; float")
+                } else {
+                    val floatFill = compTarget.machine.getFloatAsmBytes(initialValue)
+                    asmgen.out("$name\t.byte  $floatFill  ; float $initialValue")
+                }
+            }
+            DataType.STR -> {
+                throw AssemblyError("all string vars should have been interned into prog")
+            }
+            in ArrayDatatypes -> arrayVariable2asm(name, variable.dt, variable.onetimeInitializationArrayValue, variable.length)
+            else -> {
+                throw AssemblyError("weird dt")
+            }
+        }
+    }
+
+    private fun arrayVariable2asm(varname: String, dt: DataType, value: StArray?, orNumberOfZeros: Int?) {
+        when(dt) {
+            DataType.ARRAY_UB -> {
+                val data = makeArrayFillDataUnsigned(dt, value, orNumberOfZeros)
+                if (data.size <= 16)
+                    asmgen.out("$varname\t.byte  ${data.joinToString()}")
+                else {
+                    asmgen.out(varname)
+                    for (chunk in data.chunked(16))
+                        asmgen.out("  .byte  " + chunk.joinToString())
+                }
+            }
+            DataType.ARRAY_B -> {
+                val data = makeArrayFillDataSigned(dt, value, orNumberOfZeros)
+                if (data.size <= 16)
+                    asmgen.out("$varname\t.char  ${data.joinToString()}")
+                else {
+                    asmgen.out(varname)
+                    for (chunk in data.chunked(16))
+                        asmgen.out("  .char  " + chunk.joinToString())
+                }
+            }
+            DataType.ARRAY_UW -> {
+                val data = makeArrayFillDataUnsigned(dt, value, orNumberOfZeros)
+                if (data.size <= 16)
+                    asmgen.out("$varname\t.word  ${data.joinToString()}")
+                else {
+                    asmgen.out(varname)
+                    for (chunk in data.chunked(16))
+                        asmgen.out("  .word  " + chunk.joinToString())
+                }
+            }
+            DataType.ARRAY_W -> {
+                val data = makeArrayFillDataSigned(dt, value, orNumberOfZeros)
+                if (data.size <= 16)
+                    asmgen.out("$varname\t.sint  ${data.joinToString()}")
+                else {
+                    asmgen.out(varname)
+                    for (chunk in data.chunked(16))
+                        asmgen.out("  .sint  " + chunk.joinToString())
+                }
+            }
+            DataType.ARRAY_F -> {
+                val array = value ?: zeroFilledArray(orNumberOfZeros!!)
+                val floatFills = array.map {
+                    compTarget.machine.getFloatAsmBytes(it.number!!)
+                }
+                asmgen.out(varname)
+                for (f in array.zip(floatFills))
+                    asmgen.out("  .byte  ${f.second}  ; float ${f.first}")
+            }
+            else -> throw AssemblyError("require array dt")
+        }
+    }
+
+    private fun zeroFilledArray(numElts: Int): StArray {
+        val values = mutableListOf<StArrayElement>()
+        repeat(numElts) {
+            values.add(StArrayElement(0.0, null))
+        }
+        return values
+    }
+
+    private fun memdefsAndConsts2asm(memvars: Collection<StMemVar>, consts: Collection<StConstant>) {
+        memvars.forEach {
+            asmgen.out("  ${it.name} = ${it.address.toHex()}")
+        }
+        consts.forEach {
+            if(it.dt==DataType.FLOAT)
+                asmgen.out("  ${it.name} = ${it.value}")
+            else
+                asmgen.out("  ${it.name} = ${it.value.toHex()}")
+        }
+    }
+
+    private fun asmsubs2asm(statements: List<Statement>) {
+        statements
+            .filter { it is Subroutine && it.isAsmSubroutine && it.asmAddress!=null }
+            .forEach { asmsub ->
+                asmsub as Subroutine
+                asmgen.out("  ${asmsub.name} = ${asmsub.asmAddress!!.toHex()}")
+            }
+    }
+
+    private fun outputStringvar(varname: String, encoding: Encoding, value: String) {
+        asmgen.out("$varname\t; $encoding:\"${value.escape().replace("\u0000", "<NULL>")}\"", false)
+        val bytes = compTarget.encodeString(value, encoding).plus(0.toUByte())
+        val outputBytes = bytes.map { "$" + it.toString(16).padStart(2, '0') }
+        for (chunk in outputBytes.chunked(16))
+            asmgen.out("  .byte  " + chunk.joinToString())
+    }
+
+    private fun makeArrayFillDataUnsigned(dt: DataType, value: StArray?, orNumberOfZeros: Int?): List<String> {
+        val array = value ?: zeroFilledArray(orNumberOfZeros!!)
+        return when (dt) {
+            DataType.ARRAY_UB ->
+                // byte array can never contain pointer-to types, so treat values as all integers
+                array.map {
+                    val number = it.number!!.toInt()
+                    "$"+number.toString(16).padStart(2, '0')
+                }
+            DataType.ARRAY_UW -> array.map {
+                if(it.number!=null) {
+                    "$" + it.number!!.toInt().toString(16).padStart(4, '0')
+                }
+                else if(it.addressOf!=null) {
+                    asmgen.asmSymbolName(it.addressOf!!)
+                }
+                else
+                    throw AssemblyError("weird array elt")
+            }
+            else -> throw AssemblyError("invalid dt")
+        }
+    }
+
+    private fun makeArrayFillDataSigned(dt: DataType, value: StArray?, orNumberOfZeros: Int?): List<String> {
+        val array = value ?: zeroFilledArray(orNumberOfZeros!!)
+        return when (dt) {
+            // byte array can never contain pointer-to types, so treat values as all integers
+            DataType.ARRAY_UB ->
+                array.map {
+                    val number = it.number!!.toInt()
+                    "$"+number.toString(16).padStart(2, '0')
+                }
+            DataType.ARRAY_B ->
+                array.map {
+                    val number = it.number!!.toInt()
+                    val hexnum = number.absoluteValue.toString(16).padStart(2, '0')
+                    if(number>=0)
+                        "$$hexnum"
+                    else
+                        "-$$hexnum"
+                }
+            DataType.ARRAY_UW -> array.map {
+                val number = it.number!!.toInt()
+                "$" + number.toString(16).padStart(4, '0')
+            }
+            DataType.ARRAY_W -> array.map {
+                val number = it.number!!.toInt()
+                val hexnum = number.absoluteValue.toString(16).padStart(4, '0')
+                if(number>=0)
+                    "$$hexnum"
+                else
+                    "-$$hexnum"
+            }
+            else -> throw AssemblyError("invalid dt")
+        }
+    }
+
+}

codeGenCpu6502/src/prog8/codegen/cpu6502/VariableAllocator.kt

@@ -0,0 +1,129 @@
+package prog8.codegen.cpu6502
+
+import com.github.michaelbull.result.fold
+import com.github.michaelbull.result.onSuccess
+import prog8.code.StNode
+import prog8.code.StNodeType
+import prog8.code.StStaticVariable
+import prog8.code.SymbolTable
+import prog8.code.core.*
+
+
+internal class VariableAllocator(private val symboltable: SymbolTable,
+                                 private val options: CompilationOptions,
+                                 private val errors: IErrorReporter
+) {
+
+    private val zeropage = options.compTarget.machine.zeropage
+    internal val globalFloatConsts = mutableMapOf<Double, String>()     // all float values in the entire program (value -> varname)
+    internal val zeropageVars: Map<List<String>, Zeropage.ZpAllocation> = zeropage.allocatedVariables
+
+    init {
+        allocateZeropageVariables()
+    }
+
+    internal fun isZpVar(scopedName: List<String>) = scopedName in zeropage.allocatedVariables
+
+    internal fun getFloatAsmConst(number: Double): String {
+        val asmName = globalFloatConsts[number]
+        if(asmName!=null)
+            return asmName
+
+        val newName = "prog8_float_const_${globalFloatConsts.size}"
+        globalFloatConsts[number] = newName
+        return newName
+    }
+
+    /**
+     * Allocate variables into the Zeropage.
+     * The result should be retrieved from the current machine's zeropage object!
+     */
+    private fun allocateZeropageVariables() {
+        if(options.zeropage== ZeropageType.DONTUSE)
+            return
+
+        val allVariables = collectAllVariables(symboltable)
+
+        val numberOfAllocatableVariables = allVariables.size
+        val varsRequiringZp = allVariables.filter { it.zpwish == ZeropageWish.REQUIRE_ZEROPAGE }
+        val varsPreferringZp = allVariables.filter { it.zpwish == ZeropageWish.PREFER_ZEROPAGE }
+        val varsDontCare = allVariables.filter { it.zpwish == ZeropageWish.DONTCARE }
+        val numberOfExplicitNonZpVariables = allVariables.count { it.zpwish == ZeropageWish.NOT_IN_ZEROPAGE }
+        require(varsDontCare.size + varsRequiringZp.size + varsPreferringZp.size + numberOfExplicitNonZpVariables == numberOfAllocatableVariables)
+
+        var numVariablesAllocatedInZP = 0
+        var numberOfNonIntegerVariables = 0
+
+        varsRequiringZp.forEach { variable ->
+            val result = zeropage.allocate(
+                variable.scopedName,
+                variable.dt,
+                variable.length,
+                variable.position,
+                errors
+            )
+            result.fold(
+                success = {
+                    numVariablesAllocatedInZP++
+                },
+                failure = {
+                    errors.err(it.message!!, variable.position)
+                }
+            )
+        }
+
+        if(errors.noErrors()) {
+            varsPreferringZp.forEach { variable ->
+                val result = zeropage.allocate(
+                    variable.scopedName,
+                    variable.dt,
+                    variable.length,
+                    variable.position,
+                    errors
+                )
+                result.onSuccess { numVariablesAllocatedInZP++ }
+                //  no need to check for allocation error, if there is one, just allocate in normal system ram.
+            }
+
+            // try to allocate any other interger variables into the zeropage until it is full.
+            // TODO some form of intelligent priorization? most often used variables first? loopcounter vars first? ...?
+            if(errors.noErrors()) {
+                for (variable in varsDontCare.sortedBy { it.scopedName.size }) {
+                    if(variable.dt in IntegerDatatypes) {
+                        if(zeropage.free.isEmpty()) {
+                            break
+                        } else {
+                            val result = zeropage.allocate(
+                                variable.scopedName,
+                                variable.dt,
+                                variable.length,
+                                variable.position,
+                                errors
+                            )
+                            result.onSuccess { numVariablesAllocatedInZP++ }
+                        }
+                    } else
+                        numberOfNonIntegerVariables++
+                }
+            }
+        }
+
+//        println("  number of allocated vars: $numberOfAllocatableVariables")
+//        println("  put into zeropage: $numVariablesAllocatedInZP,  non-zp allocatable: ${numberOfNonIntegerVariables+numberOfExplicitNonZpVariables}")
+//        println("  zeropage free space: ${zeropage.free.size} bytes")
+    }
+
+    private fun collectAllVariables(st: SymbolTable): Collection<StStaticVariable> {
+        val vars = mutableListOf<StStaticVariable>()
+        fun collect(node: StNode) {
+            for(child in node.children) {
+                if(child.value.type == StNodeType.STATICVAR)
+                    vars.add(child.value as StStaticVariable)
+                else
+                    collect(child.value)
+            }
+        }
+        collect(st)
+        return vars
+    }
+}

codeGenCpu6502/src/prog8/codegen/cpu6502/assignment/AsmAssignment.kt

@@ -0,0 +1,215 @@
+package prog8.codegen.cpu6502.assignment
+
+import prog8.ast.Program
+import prog8.ast.expressions.*
+import prog8.ast.statements.AssignTarget
+import prog8.ast.statements.Assignment
+import prog8.ast.statements.DirectMemoryWrite
+import prog8.ast.statements.Subroutine
+import prog8.code.core.*
+import prog8.codegen.cpu6502.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,
+                               private val asmgen: AsmGen,
+                               val datatype: DataType,
+                               val scope: Subroutine?,
+                               private val variableAsmName: String? = null,
+                               val array: ArrayIndexedExpression? = null,
+                               val memory: DirectMemoryWrite? = null,
+                               val register: RegisterOrPair? = null,
+                               val origAstTarget: AssignTarget? = null
+                               )
+{
+    val constArrayIndexValue by lazy { array?.indexer?.constIndex()?.toUInt() }
+    val asmVarname: String by lazy {
+        if (array == null)
+            variableAsmName!!
+        else
+            asmgen.asmVariableName(array.arrayvar)
+    }
+
+    lateinit var origAssign: AsmAssignment
+
+    init {
+        if(register!=null && datatype !in NumericDatatypes)
+            throw AssemblyError("register must be integer or float type")
+    }
+
+    companion object {
+        fun fromAstAssignment(assign: Assignment, program: Program, asmgen: AsmGen): AsmAssignTarget {
+            with(assign.target) {
+                val idt = inferType(program)
+                val dt = idt.getOrElse { throw AssemblyError("unknown dt") }
+                when {
+                    identifier != null -> {
+                        val parameter = identifier!!.targetVarDecl(program)?.subroutineParameter
+                        if (parameter!=null) {
+                            val sub = parameter.definingSubroutine!!
+                            if (sub.isAsmSubroutine) {
+                                val reg = sub.asmParameterRegisters[sub.parameters.indexOf(parameter)]
+                                if(reg.statusflag!=null)
+                                    throw AssemblyError("can't assign value to processor statusflag directly")
+                                else
+                                    return AsmAssignTarget(TargetStorageKind.REGISTER, asmgen, dt, assign.definingSubroutine, register=reg.registerOrPair, origAstTarget = this)
+                            }
+                        }
+                        return AsmAssignTarget(TargetStorageKind.VARIABLE, asmgen, dt, assign.definingSubroutine, variableAsmName = asmgen.asmVariableName(identifier!!), origAstTarget =  this)
+                    }
+                    arrayindexed != null -> return AsmAssignTarget(TargetStorageKind.ARRAY, asmgen, dt, assign.definingSubroutine, array = arrayindexed, origAstTarget =  this)
+                    memoryAddress != null -> return AsmAssignTarget(TargetStorageKind.MEMORY, asmgen, dt, assign.definingSubroutine, memory =  memoryAddress, origAstTarget =  this)
+                    else -> throw AssemblyError("weird target")
+                }
+            }
+        }
+
+        fun fromRegisters(registers: RegisterOrPair, signed: Boolean, scope: Subroutine?, asmgen: AsmGen): AsmAssignTarget =
+                when(registers) {
+                    RegisterOrPair.A,
+                    RegisterOrPair.X,
+                    RegisterOrPair.Y -> AsmAssignTarget(TargetStorageKind.REGISTER, asmgen, if(signed) DataType.BYTE else DataType.UBYTE, scope, register = registers)
+                    RegisterOrPair.AX,
+                    RegisterOrPair.AY,
+                    RegisterOrPair.XY -> AsmAssignTarget(TargetStorageKind.REGISTER, asmgen, if(signed) DataType.WORD else DataType.UWORD, scope, register = registers)
+                    RegisterOrPair.FAC1,
+                    RegisterOrPair.FAC2 -> AsmAssignTarget(TargetStorageKind.REGISTER, asmgen, DataType.FLOAT, scope, register = registers)
+                    RegisterOrPair.R0,
+                    RegisterOrPair.R1,
+                    RegisterOrPair.R2,
+                    RegisterOrPair.R3,
+                    RegisterOrPair.R4,
+                    RegisterOrPair.R5,
+                    RegisterOrPair.R6,
+                    RegisterOrPair.R7,
+                    RegisterOrPair.R8,
+                    RegisterOrPair.R9,
+                    RegisterOrPair.R10,
+                    RegisterOrPair.R11,
+                    RegisterOrPair.R12,
+                    RegisterOrPair.R13,
+                    RegisterOrPair.R14,
+                    RegisterOrPair.R15 -> AsmAssignTarget(TargetStorageKind.REGISTER, asmgen, if(signed) DataType.WORD else DataType.UWORD, scope, register = registers)
+                }
+    }
+}
+
+internal class AsmAssignSource(val kind: SourceStorageKind,
+                               private val program: Program,
+                               private val asmgen: AsmGen,
+                               val datatype: DataType,
+                               private val variableAsmName: String? = null,
+                               val array: ArrayIndexedExpression? = null,
+                               val memory: DirectMemoryRead? = null,
+                               val register: RegisterOrPair? = null,
+                               val number: NumericLiteral? = null,
+                               val expression: Expression? = null
+)
+{
+    val asmVarname: String
+        get() = if(array==null)
+            variableAsmName!!
+        else
+            asmgen.asmVariableName(array.arrayvar)
+
+    companion object {
+        fun fromAstSource(value: Expression, program: Program, asmgen: AsmGen): AsmAssignSource {
+            val cv = value.constValue(program)
+            if(cv!=null)
+                return AsmAssignSource(SourceStorageKind.LITERALNUMBER, program, asmgen, cv.type, number = cv)
+
+            return when(value) {
+                is NumericLiteral -> throw AssemblyError("should have been constant value")
+                is StringLiteral -> throw AssemblyError("string literal value should not occur anymore for asm generation")
+                is ArrayLiteral -> throw AssemblyError("array literal value should not occur anymore for asm generation")
+                is IdentifierReference -> {
+                    val parameter = value.targetVarDecl(program)?.subroutineParameter
+                    if(parameter!=null && parameter.definingSubroutine!!.isAsmSubroutine)
+                        throw AssemblyError("can't assign from a asmsub register parameter $value ${value.position}")
+                    val dt = value.inferType(program).getOr(DataType.UNDEFINED)
+                    val varName=asmgen.asmVariableName(value)
+                    // special case: "cx16.r[0-15]" are 16-bits virtual registers of the commander X16 system
+                    if(dt == DataType.UWORD && varName.lowercase().startsWith("cx16.r")) {
+                        val regStr = varName.lowercase().substring(5)
+                        val reg = RegisterOrPair.valueOf(regStr.uppercase())
+                        AsmAssignSource(SourceStorageKind.REGISTER, program, asmgen, dt, register = reg)
+                    } else {
+                        AsmAssignSource(SourceStorageKind.VARIABLE, program, asmgen, dt, variableAsmName = varName)
+                    }
+                }
+                is DirectMemoryRead -> {
+                    AsmAssignSource(SourceStorageKind.MEMORY, program, asmgen, DataType.UBYTE, memory = value)
+                }
+                is ArrayIndexedExpression -> {
+                    val dt = value.inferType(program).getOrElse { throw AssemblyError("unknown dt") }
+                    AsmAssignSource(SourceStorageKind.ARRAY, program, asmgen, dt, array = value)
+                }
+                is BuiltinFunctionCall -> {
+                    val returnType = value.inferType(program)
+                    AsmAssignSource(SourceStorageKind.EXPRESSION, program, asmgen, returnType.getOrElse { throw AssemblyError("unknown dt") }, expression = value)
+                }
+                is FunctionCallExpression -> {
+                    val sub = value.target.targetSubroutine(program)!!
+                    val returnType = sub.returntypes.zip(sub.asmReturnvaluesRegisters).firstOrNull { rr -> rr.second.registerOrPair != null || rr.second.statusflag!=null }?.first
+                            ?: throw AssemblyError("can't translate zero return values in assignment")
+
+                    AsmAssignSource(SourceStorageKind.EXPRESSION, program, asmgen, returnType, expression = value)
+                }
+                else -> {
+                    val returnType = value.inferType(program)
+                    AsmAssignSource(SourceStorageKind.EXPRESSION, program, asmgen, returnType.getOrElse { throw AssemblyError("unknown dt") }, expression = value)
+                }
+            }
+        }
+    }
+
+    fun adjustSignedUnsigned(target: AsmAssignTarget): AsmAssignSource {
+        // allow some signed/unsigned relaxations
+
+        fun withAdjustedDt(newType: DataType) =
+                AsmAssignSource(kind, program, asmgen, newType, variableAsmName, array, memory, register, number, expression)
+
+        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,
+                             memsizer: IMemSizer,
+                             val position: Position) {
+
+    init {
+        if(target.register !in arrayOf(RegisterOrPair.XY, RegisterOrPair.AX, RegisterOrPair.AY))
+            require(source.datatype != DataType.UNDEFINED) { "must not be placeholder/undefined datatype" }
+            require(memsizer.memorySize(source.datatype) <= memsizer.memorySize(target.datatype)) {
+                "source dt size must be less or equal to target dt size at $position"
+            }
+    }
+}

codeGenExperimental/build.gradle

@@ -0,0 +1,47 @@
+
+plugins {
+    id 'java'
+    id 'application'
+    id "org.jetbrains.kotlin.jvm"
+}
+
+java {
+    toolchain {
+        languageVersion = JavaLanguageVersion.of(javaVersion)
+    }
+}
+
+compileKotlin {
+    kotlinOptions {
+        jvmTarget = javaVersion
+    }
+}
+
+compileTestKotlin {
+    kotlinOptions {
+        jvmTarget = javaVersion
+    }
+}
+
+dependencies {
+    implementation project(':codeCore')
+    implementation project(':intermediate')
+    implementation project(':codeGenIntermediate')
+    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8"
+    // implementation "org.jetbrains.kotlin:kotlin-reflect"
+    implementation "com.michael-bull.kotlin-result:kotlin-result-jvm:1.1.16"
+
+}
+
+sourceSets {
+    main {
+        java {
+            srcDirs = ["${project.projectDir}/src"]
+        }
+        resources {
+            srcDirs = ["${project.projectDir}/res"]
+        }
+    }
+}
+
+// note: there are no unit tests in this module!

codeGenExperimental/codeGenExperimental.iml

@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<module type="JAVA_MODULE" version="4">
+  <component name="NewModuleRootManager" inherit-compiler-output="true">
+    <exclude-output />
+    <content url="file://$MODULE_DIR$">
+      <sourceFolder url="file://$MODULE_DIR$/src" isTestSource="false" />
+      <excludeFolder url="file://$MODULE_DIR$/build" />
+    </content>
+    <orderEntry type="inheritedJdk" />
+    <orderEntry type="sourceFolder" forTests="false" />
+    <orderEntry type="library" name="KotlinJavaRuntime" level="project" />
+    <orderEntry type="library" name="michael.bull.kotlin.result.jvm" level="project" />
+    <orderEntry type="module" module-name="codeGenIntermediate" />
+    <orderEntry type="module" module-name="intermediate" />
+    <orderEntry type="module" module-name="codeCore" />
+  </component>
+</module>

codeGenExperimental/src/prog8/codegen/experimental/CodeGen.kt

@@ -0,0 +1,30 @@
+package prog8.codegen.experimental
+
+import prog8.code.SymbolTable
+import prog8.code.ast.PtProgram
+import prog8.code.core.CompilationOptions
+import prog8.code.core.IAssemblyGenerator
+import prog8.code.core.IAssemblyProgram
+import prog8.code.core.IErrorReporter
+import prog8.codegen.intermediate.IRCodeGen
+import prog8.intermediate.IRFileWriter
+
+class CodeGen(private val program: PtProgram,
+              private val symbolTable: SymbolTable,
+              private val options: CompilationOptions,
+              private val errors: IErrorReporter
+): IAssemblyGenerator {
+    override fun compileToAssembly(): IAssemblyProgram? {
+
+        // you could write a code generator directly on the PtProgram AST,
+        // but you can also use the Intermediate Representation to build a codegen on:
+        val irCodeGen = IRCodeGen(program, symbolTable, options, errors)
+        val irProgram = irCodeGen.generate()
+
+        // this stub only writes the IR program to disk but doesn't generate anything else.
+        IRFileWriter(irProgram).writeFile()
+
+        println("** experimental codegen stub: no assembly generated **")
+        return null
+    }
+}

codeGenIntermediate/build.gradle

@@ -0,0 +1,64 @@
+
+plugins {
+    id 'java'
+    id 'application'
+    id "org.jetbrains.kotlin.jvm"
+}
+
+java {
+    toolchain {
+        languageVersion = JavaLanguageVersion.of(javaVersion)
+    }
+}
+
+compileKotlin {
+    kotlinOptions {
+        jvmTarget = javaVersion
+    }
+}
+
+compileTestKotlin {
+    kotlinOptions {
+        jvmTarget = javaVersion
+    }
+}
+
+dependencies {
+    implementation project(':codeCore')
+    implementation project(':intermediate')
+    implementation project(':virtualmachine')
+    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8"
+    // implementation "org.jetbrains.kotlin:kotlin-reflect"
+    implementation "com.michael-bull.kotlin-result:kotlin-result-jvm:1.1.16"
+
+    testImplementation 'io.kotest:kotest-runner-junit5-jvm:5.3.2'
+}
+
+sourceSets {
+    main {
+        java {
+            srcDirs = ["${project.projectDir}/src"]
+        }
+        resources {
+            srcDirs = ["${project.projectDir}/res"]
+        }
+    }
+    test {
+        java {
+            srcDir "${project.projectDir}/test"
+        }
+    }
+}
+
+test {
+    // Enable JUnit 5 (Gradle 4.6+).
+    useJUnitPlatform()
+
+    // Always run tests, even when nothing changed.
+    dependsOn 'cleanTest'
+
+    // Show test results.
+    testLogging {
+        events "skipped", "failed"
+    }
+}

codeGenIntermediate/codeGenIntermediate.iml

@@ -0,0 +1,19 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<module type="JAVA_MODULE" version="4">
+  <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://$MODULE_DIR$/test" isTestSource="true" />
+      <excludeFolder url="file://$MODULE_DIR$/build" />
+    </content>
+    <orderEntry type="inheritedJdk" />
+    <orderEntry type="sourceFolder" forTests="false" />
+    <orderEntry type="library" name="KotlinJavaRuntime" level="project" />
+    <orderEntry type="module" module-name="codeCore" />
+    <orderEntry type="module" module-name="intermediate" />
+    <orderEntry type="module" module-name="virtualmachine" />
+    <orderEntry type="library" name="io.kotest.assertions.core.jvm" level="project" />
+    <orderEntry type="library" name="io.kotest.runner.junit5.jvm" level="project" />
+  </component>
+</module>

codeGenIntermediate/src/prog8/codegen/intermediate/AssignmentGen.kt

@@ -0,0 +1,294 @@
+package prog8.codegen.intermediate
+
+import prog8.code.ast.*
+import prog8.code.core.AssemblyError
+import prog8.code.core.DataType
+import prog8.code.core.Position
+import prog8.code.core.SignedDatatypes
+import prog8.intermediate.IRCodeChunk
+import prog8.intermediate.IRCodeInstruction
+import prog8.intermediate.Opcode
+import prog8.intermediate.VmDataType
+
+internal class AssignmentGen(private val codeGen: IRCodeGen, private val expressionEval: ExpressionGen) {
+
+    internal fun translate(assignment: PtAssignment): IRCodeChunk {
+        if(assignment.target.children.single() is PtMachineRegister)
+            throw AssemblyError("assigning to a register should be done by just evaluating the expression into resultregister")
+
+        return if (assignment.isInplaceAssign)
+            translateInplaceAssign(assignment)
+        else
+            translateRegularAssign(assignment)
+    }
+
+    private fun translateInplaceAssign(assignment: PtAssignment): IRCodeChunk {
+        val ident = assignment.target.identifier
+        val memory = assignment.target.memory
+        val array = assignment.target.array
+
+        return if(ident!=null) {
+            assignSelfInMemory(ident.targetName.joinToString("."), assignment.value, assignment)
+        } else if(memory != null) {
+            if(memory.address is PtNumber)
+                assignSelfInMemoryKnownAddress((memory.address as PtNumber).number.toInt(), assignment.value, assignment)
+            else
+                fallbackAssign(assignment)
+        } else if(array!=null) {
+            // NOTE: naive fallback assignment here will sometimes generate code that loads the index value multiple times
+            // in a register. It's way too much work to optimize that here - instead, we trust that the generated IL assembly
+            // will be optimized later and have the double assignments removed.
+            fallbackAssign(assignment)
+        } else {
+            fallbackAssign(assignment)
+        }
+    }
+
+    private fun assignSelfInMemoryKnownAddress(
+        address: Int,
+        value: PtExpression,
+        origAssign: PtAssignment
+    ): IRCodeChunk {
+        val vmDt = codeGen.vmType(value.type)
+        val code = IRCodeChunk(origAssign.position)
+        when(value) {
+            is PtIdentifier -> return code // do nothing, x=x null assignment.
+            is PtMachineRegister -> return code // do nothing, reg=reg null assignment
+            is PtPrefix -> return inplacePrefix(value.operator, vmDt, address, null, value.position)
+            is PtBinaryExpression -> return inplaceBinexpr(value.operator, value.right, vmDt, value.type in SignedDatatypes, address, null, origAssign)
+            is PtMemoryByte -> {
+                return if (!codeGen.options.compTarget.machine.isIOAddress(address.toUInt()))
+                    code // do nothing, mem=mem null assignment.
+                else {
+                    // read and write a (i/o) memory location to itself.
+                    val tempReg = codeGen.vmRegisters.nextFree()
+                    code += IRCodeInstruction(Opcode.LOADM, vmDt, reg1 = tempReg, value = address)
+                    code += IRCodeInstruction(Opcode.STOREM, vmDt, reg1 = tempReg, value = address)
+                    code
+                }
+            }
+            else -> return fallbackAssign(origAssign)
+        }
+    }
+
+    private fun assignSelfInMemory(
+        symbol: String,
+        value: PtExpression,
+        origAssign: PtAssignment
+    ): IRCodeChunk {
+        val vmDt = codeGen.vmType(value.type)
+        val code = IRCodeChunk(origAssign.position)
+        when(value) {
+            is PtIdentifier -> return code // do nothing, x=x null assignment.
+            is PtMachineRegister -> return code // do nothing, reg=reg null assignment
+            is PtPrefix -> return inplacePrefix(value.operator, vmDt, null, symbol, value.position)
+            is PtBinaryExpression -> return inplaceBinexpr(value.operator, value.right, vmDt, value.type in SignedDatatypes, null, symbol, origAssign)
+            is PtMemoryByte -> {
+                val tempReg = codeGen.vmRegisters.nextFree()
+                code += IRCodeInstruction(Opcode.LOADM, vmDt, reg1 = tempReg, labelSymbol = symbol)
+                code += IRCodeInstruction(Opcode.STOREM, vmDt, reg1 = tempReg, labelSymbol = symbol)
+                return code
+            }
+            else -> return fallbackAssign(origAssign)
+        }
+    }
+
+    private fun fallbackAssign(origAssign: PtAssignment): IRCodeChunk {
+        if (codeGen.options.slowCodegenWarnings)
+            codeGen.errors.warn("indirect code for in-place assignment", origAssign.position)
+        return translateRegularAssign(origAssign)
+    }
+
+    private fun inplaceBinexpr(
+        operator: String,
+        operand: PtExpression,
+        vmDt: VmDataType,
+        signed: Boolean,
+        knownAddress: Int?,
+        symbol: String?,
+        origAssign: PtAssignment
+    ): IRCodeChunk {
+        if(knownAddress!=null) {
+            when (operator) {
+                "+" -> return expressionEval.operatorPlusInplace(knownAddress, null, vmDt, operand)
+                "-" -> return expressionEval.operatorMinusInplace(knownAddress, null, vmDt, operand)
+                "*" -> return expressionEval.operatorMultiplyInplace(knownAddress, null, vmDt, operand)
+                "/" -> return expressionEval.operatorDivideInplace(knownAddress, null, vmDt, signed, operand)
+                "|" -> return expressionEval.operatorOrInplace(knownAddress, null, vmDt, operand)
+                "&" -> return expressionEval.operatorAndInplace(knownAddress, null, vmDt, operand)
+                "^" -> return expressionEval.operatorXorInplace(knownAddress, null, vmDt, operand)
+                "<<" -> return expressionEval.operatorShiftLeftInplace(knownAddress, null, vmDt, operand)
+                ">>" -> return expressionEval.operatorShiftRightInplace(knownAddress, null, vmDt, signed, operand)
+                else -> {}
+            }
+        } else {
+            symbol!!
+            when (operator) {
+                "+" -> return expressionEval.operatorPlusInplace(null, symbol, vmDt, operand)
+                "-" -> return expressionEval.operatorMinusInplace(null, symbol, vmDt, operand)
+                "*" -> return expressionEval.operatorMultiplyInplace(null, symbol, vmDt, operand)
+                "/" -> return expressionEval.operatorDivideInplace(null, symbol, vmDt, signed, operand)
+                "|" -> return expressionEval.operatorOrInplace(null, symbol, vmDt, operand)
+                "&" -> return expressionEval.operatorAndInplace(null, symbol, vmDt, operand)
+                "^" -> return expressionEval.operatorXorInplace(null, symbol, vmDt, operand)
+                "<<" -> return expressionEval.operatorShiftLeftInplace(null, symbol, vmDt, operand)
+                ">>" -> return expressionEval.operatorShiftRightInplace(null, symbol, vmDt, signed, operand)
+                else -> {}
+            }
+        }
+        return fallbackAssign(origAssign)
+    }
+
+    private fun inplacePrefix(operator: String, vmDt: VmDataType, knownAddress: Int?, addressSymbol: String?, position: Position): IRCodeChunk {
+        val code= IRCodeChunk(position)
+        when(operator) {
+            "+" -> { }
+            "-" -> {
+                code += if(knownAddress!=null)
+                    IRCodeInstruction(Opcode.NEGM, vmDt, value = knownAddress)
+                else
+                    IRCodeInstruction(Opcode.NEGM, vmDt, labelSymbol = addressSymbol)
+            }
+            "~" -> {
+                val regMask = codeGen.vmRegisters.nextFree()
+                val mask = if(vmDt==VmDataType.BYTE) 0x00ff else 0xffff
+                code += IRCodeInstruction(Opcode.LOAD, vmDt, reg1=regMask, value = mask)
+                code += if(knownAddress!=null)
+                    IRCodeInstruction(Opcode.XORM, vmDt, reg1=regMask, value = knownAddress)
+                else
+                    IRCodeInstruction(Opcode.XORM, vmDt, reg1=regMask, labelSymbol = addressSymbol)
+            }
+            else -> throw AssemblyError("weird prefix operator")
+        }
+        return code
+    }
+
+    private fun translateRegularAssign(assignment: PtAssignment): IRCodeChunk {
+        // note: assigning array and string values is done via an explicit memcopy/stringcopy function call.
+        val ident = assignment.target.identifier
+        val memory = assignment.target.memory
+        val array = assignment.target.array
+        val vmDt = codeGen.vmType(assignment.value.type)
+
+        val code = IRCodeChunk(assignment.position)
+        var resultRegister = -1
+        var resultFpRegister = -1
+        val zero = codeGen.isZero(assignment.value)
+        if(!zero) {
+            // calculate the assignment value
+            if (vmDt == VmDataType.FLOAT) {
+                resultFpRegister = codeGen.vmRegisters.nextFreeFloat()
+                code += expressionEval.translateExpression(assignment.value, -1, resultFpRegister)
+            } else {
+                resultRegister = if (assignment.value is PtMachineRegister) {
+                    (assignment.value as PtMachineRegister).register
+                } else {
+                    val reg = codeGen.vmRegisters.nextFree()
+                    code += expressionEval.translateExpression(assignment.value, reg, -1)
+                    reg
+                }
+            }
+        }
+        if(ident!=null) {
+            val symbol = ident.targetName.joinToString(".")
+            code += if(zero) {
+                IRCodeInstruction(Opcode.STOREZM, vmDt, labelSymbol = symbol)
+            } else {
+                if (vmDt == VmDataType.FLOAT)
+                    IRCodeInstruction(Opcode.STOREM, vmDt, fpReg1 = resultFpRegister, labelSymbol = symbol)
+                else
+                    IRCodeInstruction(Opcode.STOREM, vmDt, reg1 = resultRegister, labelSymbol = symbol)
+            }
+        }
+        else if(array!=null) {
+            val variable = array.variable.targetName.joinToString(".")
+            val itemsize = codeGen.program.memsizer.memorySize(array.type)
+
+            if(array.variable.type==DataType.UWORD) {
+                // indexing a pointer var instead of a real array or string
+                if(itemsize!=1)
+                    throw AssemblyError("non-array var indexing requires bytes dt")
+                if(array.index.type!=DataType.UBYTE)
+                    throw AssemblyError("non-array var indexing requires bytes index")
+                val idxReg = codeGen.vmRegisters.nextFree()
+                code += expressionEval.translateExpression(array.index, idxReg, -1)
+                if(zero) {
+                    // there's no STOREZIX instruction
+                    resultRegister = codeGen.vmRegisters.nextFree()
+                    code += IRCodeInstruction(Opcode.LOAD, vmDt, reg1=resultRegister, value=0)
+                }
+                code += IRCodeInstruction(Opcode.STOREIX, vmDt, reg1=resultRegister, reg2=idxReg, labelSymbol = variable)
+                return code
+            }
+
+            val fixedIndex = constIntValue(array.index)
+            if(zero) {
+                if(fixedIndex!=null) {
+                    val offset = fixedIndex*itemsize
+                    code += IRCodeInstruction(Opcode.STOREZM, vmDt, labelSymbol = "$variable+$offset")
+                } else {
+                    val indexReg = codeGen.vmRegisters.nextFree()
+                    code += loadIndexReg(array, itemsize, indexReg, array.position)
+                    code += IRCodeInstruction(Opcode.STOREZX, vmDt, reg1=indexReg, labelSymbol = variable)
+                }
+            } else {
+                if(vmDt== VmDataType.FLOAT) {
+                    if(fixedIndex!=null) {
+                        val offset = fixedIndex*itemsize
+                        code += IRCodeInstruction(Opcode.STOREM, vmDt, fpReg1 = resultFpRegister, labelSymbol = "$variable+$offset")
+                    } else {
+                        val indexReg = codeGen.vmRegisters.nextFree()
+                        code += loadIndexReg(array, itemsize, indexReg, array.position)
+                        code += IRCodeInstruction(Opcode.STOREX, vmDt, reg1 = resultRegister, reg2=indexReg, labelSymbol = variable)
+                    }
+                } else {
+                    if(fixedIndex!=null) {
+                        val offset = fixedIndex*itemsize
+                        code += IRCodeInstruction(Opcode.STOREM, vmDt, reg1 = resultRegister, labelSymbol = "$variable+$offset")
+                    } else {
+                        val indexReg = codeGen.vmRegisters.nextFree()
+                        code += loadIndexReg(array, itemsize, indexReg, array.position)
+                        code += IRCodeInstruction(Opcode.STOREX, vmDt, reg1 = resultRegister, reg2=indexReg, labelSymbol = variable)
+                    }
+                }
+            }
+        }
+        else if(memory!=null) {
+            require(vmDt== VmDataType.BYTE)
+            if(zero) {
+                if(memory.address is PtNumber) {
+                    code += IRCodeInstruction(Opcode.STOREZM, vmDt, value=(memory.address as PtNumber).number.toInt())
+                } else {
+                    val addressReg = codeGen.vmRegisters.nextFree()
+                    code += expressionEval.translateExpression(memory.address, addressReg, -1)
+                    code += IRCodeInstruction(Opcode.STOREZI, vmDt, reg1=addressReg)
+                }
+            } else {
+                if(memory.address is PtNumber) {
+                    code += IRCodeInstruction(Opcode.STOREM, vmDt, reg1=resultRegister, value=(memory.address as PtNumber).number.toInt())
+                } else {
+                    val addressReg = codeGen.vmRegisters.nextFree()
+                    code += expressionEval.translateExpression(memory.address, addressReg, -1)
+                    code += IRCodeInstruction(Opcode.STOREI, vmDt, reg1=resultRegister, reg2=addressReg)
+                }
+            }
+        }
+        else
+            throw AssemblyError("weird assigntarget")
+        return code
+    }
+
+    private fun loadIndexReg(array: PtArrayIndexer, itemsize: Int, indexReg: Int, position: Position): IRCodeChunk {
+        val code = IRCodeChunk(position)
+        if(itemsize==1) {
+            code += expressionEval.translateExpression(array.index, indexReg, -1)
+        }
+        else {
+            val mult = PtBinaryExpression("*", DataType.UBYTE, array.position)
+            mult.children += array.index
+            mult.children += PtNumber(DataType.UBYTE, itemsize.toDouble(), array.position)
+            code += expressionEval.translateExpression(mult, indexReg, -1)
+        }
+        return code
+    }
+}

codeGenIntermediate/src/prog8/codegen/intermediate/BuiltinFuncGen.kt

@@ -0,0 +1,369 @@
+package prog8.codegen.intermediate
+
+import prog8.code.StStaticVariable
+import prog8.code.ast.*
+import prog8.code.core.AssemblyError
+import prog8.code.core.DataType
+import prog8.code.core.Position
+import prog8.intermediate.*
+import prog8.vm.Syscall
+
+
+internal class BuiltinFuncGen(private val codeGen: IRCodeGen, private val exprGen: ExpressionGen) {
+
+    fun translate(call: PtBuiltinFunctionCall, resultRegister: Int): IRCodeChunk {
+        return when(call.name) {
+            "any" -> funcAny(call, resultRegister)
+            "all" -> funcAll(call, resultRegister)
+            "abs" -> funcAbs(call, resultRegister)
+            "cmp" -> funcCmp(call)
+            "sgn" -> funcSgn(call, resultRegister)
+            "sqrt16" -> funcSqrt16(call, resultRegister)
+            "pop" -> funcPop(call)
+            "popw" -> funcPopw(call)
+            "push" -> funcPush(call)
+            "pushw" -> funcPushw(call)
+            "rsave",
+            "rsavex",
+            "rrestore",
+            "rrestorex" -> IRCodeChunk(call.position) // vm doesn't have registers to save/restore
+            "rnd" -> funcRnd(resultRegister, call.position)
+            "rndw" -> funcRndw(resultRegister, call.position)
+            "callfar" -> throw AssemblyError("callfar() is for cx16 target only")
+            "callrom" -> throw AssemblyError("callrom() is for cx16 target only")
+            "msb" -> funcMsb(call, resultRegister)
+            "lsb" -> funcLsb(call, resultRegister)
+            "memory" -> funcMemory(call, resultRegister)
+            "peek" -> funcPeek(call, resultRegister)
+            "peekw" -> funcPeekW(call, resultRegister)
+            "poke" -> funcPoke(call)
+            "pokew" -> funcPokeW(call)
+            "pokemon" -> IRCodeChunk(call.position)
+            "mkword" -> funcMkword(call, resultRegister)
+            "sort" -> funcSort(call)
+            "reverse" -> funcReverse(call)
+            "rol" -> funcRolRor(Opcode.ROXL, call, resultRegister)
+            "ror" -> funcRolRor(Opcode.ROXR, call, resultRegister)
+            "rol2" -> funcRolRor(Opcode.ROL, call, resultRegister)
+            "ror2" -> funcRolRor(Opcode.ROR, call, resultRegister)
+            else -> throw AssemblyError("missing builtinfunc for ${call.name}")
+        }
+    }
+
+    private fun funcCmp(call: PtBuiltinFunctionCall): IRCodeChunk {
+        val code = IRCodeChunk(call.position)
+        val leftRegister = codeGen.vmRegisters.nextFree()
+        val rightRegister = codeGen.vmRegisters.nextFree()
+        code += exprGen.translateExpression(call.args[0], leftRegister, -1)
+        code += exprGen.translateExpression(call.args[1], rightRegister, -1)
+        code += IRCodeInstruction(Opcode.CMP, codeGen.vmType(call.args[0].type), reg1=leftRegister, reg2=rightRegister)
+        return code
+    }
+
+    private fun funcAny(call: PtBuiltinFunctionCall, resultRegister: Int): IRCodeChunk {
+        val arrayName = call.args[0] as PtIdentifier
+        val array = codeGen.symbolTable.flat.getValue(arrayName.targetName) as StStaticVariable
+        val code = IRCodeChunk(call.position)
+        val syscall =
+            when (array.dt) {
+                DataType.ARRAY_UB,
+                DataType.ARRAY_B -> Syscall.ANY_BYTE
+                DataType.ARRAY_UW,
+                DataType.ARRAY_W -> Syscall.ANY_WORD
+                DataType.ARRAY_F -> Syscall.ANY_FLOAT
+                else -> throw IllegalArgumentException("weird type")
+            }
+        code += exprGen.translateExpression(call.args[0], 0, -1)
+        code += IRCodeInstruction(Opcode.LOAD, VmDataType.BYTE, reg1 = 1, value = array.length)
+        code += IRCodeInstruction(Opcode.SYSCALL, value = syscall.ordinal)
+        if (resultRegister != 0)
+            code += IRCodeInstruction(Opcode.LOADR, VmDataType.BYTE, reg1 = resultRegister, reg2 = 0)
+        return code
+    }
+
+    private fun funcAll(call: PtBuiltinFunctionCall, resultRegister: Int): IRCodeChunk {
+        val arrayName = call.args[0] as PtIdentifier
+        val array = codeGen.symbolTable.flat.getValue(arrayName.targetName) as StStaticVariable
+        val syscall =
+            when(array.dt) {
+                DataType.ARRAY_UB,
+                DataType.ARRAY_B -> Syscall.ALL_BYTE
+                DataType.ARRAY_UW,
+                DataType.ARRAY_W -> Syscall.ALL_WORD
+                DataType.ARRAY_F -> Syscall.ALL_FLOAT
+                else -> throw IllegalArgumentException("weird type")
+            }
+        val code = IRCodeChunk(call.position)
+        code += exprGen.translateExpression(call.args[0], 0, -1)
+        code += IRCodeInstruction(Opcode.LOAD, VmDataType.BYTE, reg1=1, value=array.length)
+        code += IRCodeInstruction(Opcode.SYSCALL, value=syscall.ordinal)
+        if(resultRegister!=0)
+            code += IRCodeInstruction(Opcode.LOADR, VmDataType.BYTE, reg1=resultRegister, reg2=0)
+        return code
+    }
+
+    private fun funcAbs(call: PtBuiltinFunctionCall, resultRegister: Int): IRCodeChunk {
+        val code = IRCodeChunk(call.position)
+        val sourceDt = call.args.single().type
+        if(sourceDt!=DataType.UWORD) {
+            code += exprGen.translateExpression(call.args[0], resultRegister, -1)
+            when (sourceDt) {
+                DataType.UBYTE -> {
+                    code += IRCodeInstruction(Opcode.EXT, VmDataType.BYTE, reg1=resultRegister)
+                }
+                DataType.BYTE -> {
+                    val notNegativeLabel = codeGen.createLabelName()
+                    val compareReg = codeGen.vmRegisters.nextFree()
+                    code += IRCodeInstruction(Opcode.LOADR, VmDataType.BYTE, reg1=compareReg, reg2=resultRegister)
+                    code += IRCodeInstruction(Opcode.AND, VmDataType.BYTE, reg1=compareReg, value=0x80)
+                    code += IRCodeInstruction(Opcode.BZ, VmDataType.BYTE, reg1=compareReg, labelSymbol = notNegativeLabel)
+                    code += IRCodeInstruction(Opcode.NEG, VmDataType.BYTE, reg1=resultRegister)
+                    code += IRCodeInstruction(Opcode.EXT, VmDataType.BYTE, reg1=resultRegister)
+                    code += IRCodeLabel(notNegativeLabel)
+                }
+                DataType.WORD -> {
+                    val notNegativeLabel = codeGen.createLabelName()
+                    val compareReg = codeGen.vmRegisters.nextFree()
+                    code += IRCodeInstruction(Opcode.LOADR, VmDataType.WORD, reg1=compareReg, reg2=resultRegister)
+                    code += IRCodeInstruction(Opcode.AND, VmDataType.WORD, reg1=compareReg, value=0x8000)
+                    code += IRCodeInstruction(Opcode.BZ, VmDataType.WORD, reg1=compareReg, labelSymbol = notNegativeLabel)
+                    code += IRCodeInstruction(Opcode.NEG, VmDataType.WORD, reg1=resultRegister)
+                    code += IRCodeLabel(notNegativeLabel)
+                }
+                else -> throw AssemblyError("weird type")
+            }
+        }
+        return code
+    }
+
+    private fun funcSgn(call: PtBuiltinFunctionCall, resultRegister: Int): IRCodeChunk {
+        val code = IRCodeChunk(call.position)
+        val reg = codeGen.vmRegisters.nextFree()
+        code += exprGen.translateExpression(call.args.single(), reg, -1)
+        code += IRCodeInstruction(Opcode.SGN, codeGen.vmType(call.type), reg1=resultRegister, reg2=reg)
+        return code
+    }
+
+    private fun funcSqrt16(call: PtBuiltinFunctionCall, resultRegister: Int): IRCodeChunk {
+        val code = IRCodeChunk(call.position)
+        val reg = codeGen.vmRegisters.nextFree()
+        code += exprGen.translateExpression(call.args.single(), reg, -1)
+        code += IRCodeInstruction(Opcode.SQRT, VmDataType.WORD, reg1=resultRegister, reg2=reg)
+        return code
+    }
+
+    private fun funcPop(call: PtBuiltinFunctionCall): IRCodeChunk {
+        val code = IRCodeChunk(call.position)
+        val reg = codeGen.vmRegisters.nextFree()
+        code += IRCodeInstruction(Opcode.POP, VmDataType.BYTE, reg1=reg)
+        code += assignRegisterTo(call.args.single(), reg)
+        return code
+    }
+
+    private fun funcPopw(call: PtBuiltinFunctionCall): IRCodeChunk {
+        val code = IRCodeChunk(call.position)
+        val reg = codeGen.vmRegisters.nextFree()
+        code += IRCodeInstruction(Opcode.POP, VmDataType.WORD, reg1=reg)
+        code += assignRegisterTo(call.args.single(), reg)
+        return code
+    }
+
+    private fun funcPush(call: PtBuiltinFunctionCall): IRCodeChunk {
+        val code = IRCodeChunk(call.position)
+        val reg = codeGen.vmRegisters.nextFree()
+        code += exprGen.translateExpression(call.args.single(), reg, -1)
+        code += IRCodeInstruction(Opcode.PUSH, VmDataType.BYTE, reg1=reg)
+        return code
+    }
+
+    private fun funcPushw(call: PtBuiltinFunctionCall): IRCodeChunk {
+        val code = IRCodeChunk(call.position)
+        val reg = codeGen.vmRegisters.nextFree()
+        code += exprGen.translateExpression(call.args.single(), reg, -1)
+        code += IRCodeInstruction(Opcode.PUSH, VmDataType.WORD, reg1=reg)
+        return code
+    }
+
+    private fun funcReverse(call: PtBuiltinFunctionCall): IRCodeChunk {
+        val arrayName = call.args[0] as PtIdentifier
+        val array = codeGen.symbolTable.flat.getValue(arrayName.targetName) as StStaticVariable
+        val sortSyscall =
+            when(array.dt) {
+                DataType.ARRAY_UB, DataType.ARRAY_B, DataType.STR -> Syscall.REVERSE_BYTES
+                DataType.ARRAY_UW, DataType.ARRAY_W -> Syscall.REVERSE_WORDS
+                DataType.ARRAY_F -> Syscall.REVERSE_FLOATS
+                else -> throw IllegalArgumentException("weird type to reverse")
+            }
+        val code = IRCodeChunk(call.position)
+        code += exprGen.translateExpression(call.args[0], 0, -1)
+        code += IRCodeInstruction(Opcode.LOAD, VmDataType.BYTE, reg1=1, value=array.length)
+        code += IRCodeInstruction(Opcode.SYSCALL, value=sortSyscall.ordinal)
+        return code
+    }
+
+    private fun funcSort(call: PtBuiltinFunctionCall): IRCodeChunk {
+        val arrayName = call.args[0] as PtIdentifier
+        val array = codeGen.symbolTable.flat.getValue(arrayName.targetName) as StStaticVariable
+        val sortSyscall =
+            when(array.dt) {
+                DataType.ARRAY_UB -> Syscall.SORT_UBYTE
+                DataType.ARRAY_B -> Syscall.SORT_BYTE
+                DataType.ARRAY_UW -> Syscall.SORT_UWORD
+                DataType.ARRAY_W -> Syscall.SORT_WORD
+                DataType.STR -> Syscall.SORT_UBYTE
+                DataType.ARRAY_F -> throw IllegalArgumentException("sorting a floating point array is not supported")
+                else -> throw IllegalArgumentException("weird type to sort")
+            }
+        val code = IRCodeChunk(call.position)
+        code += exprGen.translateExpression(call.args[0], 0, -1)
+        code += IRCodeInstruction(Opcode.LOAD, VmDataType.BYTE, reg1=1, value=array.length)
+        code += IRCodeInstruction(Opcode.SYSCALL, value=sortSyscall.ordinal)
+        return code
+    }
+
+    private fun funcMkword(call: PtBuiltinFunctionCall, resultRegister: Int): IRCodeChunk {
+        val msbReg = codeGen.vmRegisters.nextFree()
+        val code = IRCodeChunk(call.position)
+        code += exprGen.translateExpression(call.args[0], msbReg, -1)
+        code += exprGen.translateExpression(call.args[1], resultRegister, -1)
+        code += IRCodeInstruction(Opcode.CONCAT, VmDataType.BYTE, reg1=resultRegister, reg2=msbReg)
+        return code
+    }
+
+    private fun funcPokeW(call: PtBuiltinFunctionCall): IRCodeChunk {
+        val code = IRCodeChunk(call.position)
+        if(codeGen.isZero(call.args[1])) {
+            if (call.args[0] is PtNumber) {
+                val address = (call.args[0] as PtNumber).number.toInt()
+                code += IRCodeInstruction(Opcode.STOREZM, VmDataType.WORD, value = address)
+            } else {
+                val addressReg = codeGen.vmRegisters.nextFree()
+                code += exprGen.translateExpression(call.args[0], addressReg, -1)
+                code += IRCodeInstruction(Opcode.STOREZI, VmDataType.WORD, reg2 = addressReg)
+            }
+        } else {
+            val valueReg = codeGen.vmRegisters.nextFree()
+            if (call.args[0] is PtNumber) {
+                val address = (call.args[0] as PtNumber).number.toInt()
+                code += exprGen.translateExpression(call.args[1], valueReg, -1)
+                code += IRCodeInstruction(Opcode.STOREM, VmDataType.WORD, reg1 = valueReg, value = address)
+            } else {
+                val addressReg = codeGen.vmRegisters.nextFree()
+                code += exprGen.translateExpression(call.args[0], addressReg, -1)
+                code += exprGen.translateExpression(call.args[1], valueReg, -1)
+                code += IRCodeInstruction(Opcode.STOREI, VmDataType.WORD, reg1 = valueReg, reg2 = addressReg)
+            }
+        }
+        return code
+    }
+
+    private fun funcPoke(call: PtBuiltinFunctionCall): IRCodeChunk {
+        val code = IRCodeChunk(call.position)
+        if(codeGen.isZero(call.args[1])) {
+            if (call.args[0] is PtNumber) {
+                val address = (call.args[0] as PtNumber).number.toInt()
+                code += IRCodeInstruction(Opcode.STOREZM, VmDataType.BYTE, value = address)
+            } else {
+                val addressReg = codeGen.vmRegisters.nextFree()
+                code += exprGen.translateExpression(call.args[0], addressReg, -1)
+                code += IRCodeInstruction(Opcode.STOREZI, VmDataType.BYTE, reg2 = addressReg)
+            }
+        } else {
+            val valueReg = codeGen.vmRegisters.nextFree()
+            if (call.args[0] is PtNumber) {
+                val address = (call.args[0] as PtNumber).number.toInt()
+                code += exprGen.translateExpression(call.args[1], valueReg, -1)
+                code += IRCodeInstruction(Opcode.STOREM, VmDataType.BYTE, reg1 = valueReg, value = address)
+            } else {
+                val addressReg = codeGen.vmRegisters.nextFree()
+                code += exprGen.translateExpression(call.args[0], addressReg, -1)
+                code += exprGen.translateExpression(call.args[1], valueReg, -1)
+                code += IRCodeInstruction(Opcode.STOREI, VmDataType.BYTE, reg1 = valueReg, reg2 = addressReg)
+            }
+        }
+        return code
+    }
+
+    private fun funcPeekW(call: PtBuiltinFunctionCall, resultRegister: Int): IRCodeChunk {
+        val code = IRCodeChunk(call.position)
+        if(call.args[0] is PtNumber) {
+            val address = (call.args[0] as PtNumber).number.toInt()
+            code += IRCodeInstruction(Opcode.LOADM, VmDataType.WORD, reg1 = resultRegister, value = address)
+        } else {
+            val addressReg = codeGen.vmRegisters.nextFree()
+            code += exprGen.translateExpression(call.args.single(), addressReg, -1)
+            code += IRCodeInstruction(Opcode.LOADI, VmDataType.WORD, reg1 = resultRegister, reg2 = addressReg)
+        }
+        return code
+    }
+
+    private fun funcPeek(call: PtBuiltinFunctionCall, resultRegister: Int): IRCodeChunk {
+        val code = IRCodeChunk(call.position)
+        if(call.args[0] is PtNumber) {
+            val address = (call.args[0] as PtNumber).number.toInt()
+            code += IRCodeInstruction(Opcode.LOADM, VmDataType.BYTE, reg1 = resultRegister, value = address)
+        } else {
+            val addressReg = codeGen.vmRegisters.nextFree()
+            code += exprGen.translateExpression(call.args.single(), addressReg, -1)
+            code += IRCodeInstruction(Opcode.LOADI, VmDataType.BYTE, reg1 = resultRegister, reg2 = addressReg)
+        }
+        return code
+    }
+
+    private fun funcRnd(resultRegister: Int, position: Position): IRCodeChunk {
+        val code = IRCodeChunk(position)
+        code += IRCodeInstruction(Opcode.RND, VmDataType.BYTE, reg1=resultRegister)
+        return code
+    }
+
+    private fun funcRndw(resultRegister: Int, position: Position): IRCodeChunk {
+        val code = IRCodeChunk(position)
+        code += IRCodeInstruction(Opcode.RND, VmDataType.WORD, reg1=resultRegister)
+        return code
+    }
+
+    private fun funcMemory(call: PtBuiltinFunctionCall, resultRegister: Int): IRCodeChunk {
+        val name = (call.args[0] as PtString).value
+        val size = (call.args[1] as PtNumber).number.toUInt()
+        val align = (call.args[2] as PtNumber).number.toUInt()
+        val label = codeGen.addMemorySlab(name, size, align, call.position)
+        val code = IRCodeChunk(call.position)
+        code += IRCodeInstruction(Opcode.LOAD, VmDataType.WORD, reg1=resultRegister, labelSymbol = label)
+        return code
+    }
+
+    private fun funcLsb(call: PtBuiltinFunctionCall, resultRegister: Int): IRCodeChunk {
+        val code = IRCodeChunk(call.position)
+        code += exprGen.translateExpression(call.args.single(), resultRegister, -1)
+        // note: if a word result is needed, the upper byte is cleared by the typecast that follows. No need to do it here.
+        return code
+    }
+
+    private fun funcMsb(call: PtBuiltinFunctionCall, resultRegister: Int): IRCodeChunk {
+        val code = IRCodeChunk(call.position)
+        code += exprGen.translateExpression(call.args.single(), resultRegister, -1)
+        code += IRCodeInstruction(Opcode.MSIG, VmDataType.BYTE, reg1 = resultRegister, reg2=resultRegister)
+        // note: if a word result is needed, the upper byte is cleared by the typecast that follows. No need to do it here.
+        return code
+    }
+
+    private fun funcRolRor(opcode: Opcode, call: PtBuiltinFunctionCall, resultRegister: Int): IRCodeChunk {
+        val vmDt = codeGen.vmType(call.args[0].type)
+        val code = IRCodeChunk(call.position)
+        code += exprGen.translateExpression(call.args[0], resultRegister, -1)
+        code += IRCodeInstruction(opcode, vmDt, reg1=resultRegister)
+        code += assignRegisterTo(call.args[0], resultRegister)
+        return code
+    }
+
+    private fun assignRegisterTo(target: PtExpression, register: Int): IRCodeChunk {
+        val code = IRCodeChunk(target.position)
+        val assignment = PtAssignment(target.position)
+        val assignTarget = PtAssignTarget(target.position)
+        assignTarget.children.add(target)
+        assignment.children.add(assignTarget)
+        assignment.children.add(PtMachineRegister(register, target.type, target.position))
+        code += codeGen.translateNode(assignment)
+        return code
+    }
+}

codeGenIntermediate/src/prog8/codegen/intermediate/ExpressionGen.kt

@@ -0,0 +1,947 @@
+package prog8.codegen.intermediate
+
+import prog8.code.StRomSub
+import prog8.code.StStaticVariable
+import prog8.code.StSub
+import prog8.code.ast.*
+import prog8.code.core.*
+import prog8.intermediate.*
+
+
+internal class ExpressionGen(private val codeGen: IRCodeGen) {
+    fun translateExpression(expr: PtExpression, resultRegister: Int, resultFpRegister: Int): IRCodeChunk {
+        require(codeGen.vmRegisters.peekNext() > resultRegister)
+
+        val code = IRCodeChunk(expr.position)
+
+        when (expr) {
+            is PtMachineRegister -> {
+                if(resultRegister!=expr.register) {
+                    val vmDt = codeGen.vmType(expr.type)
+                    code += IRCodeInstruction(Opcode.LOADR, vmDt, reg1=resultRegister, reg2=expr.register)
+                }
+            }
+            is PtNumber -> {
+                val vmDt = codeGen.vmType(expr.type)
+                code += if(vmDt==VmDataType.FLOAT)
+                    IRCodeInstruction(Opcode.LOAD, vmDt, fpReg1 = resultFpRegister, fpValue = expr.number.toFloat())
+                else
+                    IRCodeInstruction(Opcode.LOAD, vmDt, reg1=resultRegister, value=expr.number.toInt())
+            }
+            is PtIdentifier -> {
+                val vmDt = codeGen.vmType(expr.type)
+                val symbol = expr.targetName.joinToString(".")
+                code += if (expr.type in PassByValueDatatypes) {
+                    if(vmDt==VmDataType.FLOAT)
+                        IRCodeInstruction(Opcode.LOADM, vmDt, fpReg1 = resultFpRegister, labelSymbol = symbol)
+                    else
+                        IRCodeInstruction(Opcode.LOADM, vmDt, reg1 = resultRegister, labelSymbol = symbol)
+                } else {
+                    // for strings and arrays etc., load the *address* of the value instead
+                    IRCodeInstruction(Opcode.LOAD, vmDt, reg1 = resultRegister, labelSymbol = symbol)
+                }
+            }
+            is PtAddressOf -> {
+                val vmDt = codeGen.vmType(expr.type)
+                val symbol = expr.identifier.targetName.joinToString(".")
+                // note: LOAD <symbol>  gets you the address of the symbol, whereas LOADM <symbol> would get you the value stored at that location
+                code += IRCodeInstruction(Opcode.LOAD, vmDt, reg1=resultRegister, labelSymbol = symbol)
+            }
+            is PtMemoryByte -> {
+                if(expr.address is PtNumber) {
+                    val address = (expr.address as PtNumber).number.toInt()
+                    code += IRCodeInstruction(Opcode.LOADM, VmDataType.BYTE, reg1=resultRegister, value = address)
+                } else {
+                    val addressRegister = codeGen.vmRegisters.nextFree()
+                    code += translateExpression(expr.address, addressRegister, -1)
+                    code += IRCodeInstruction(Opcode.LOADI, VmDataType.BYTE, reg1=resultRegister, reg2=addressRegister)
+                }
+            }
+            is PtTypeCast -> code += translate(expr, resultRegister, resultFpRegister)
+            is PtPrefix -> code += translate(expr, resultRegister)
+            is PtArrayIndexer -> code += translate(expr, resultRegister, resultFpRegister)
+            is PtBinaryExpression -> code += translate(expr, resultRegister, resultFpRegister)
+            is PtBuiltinFunctionCall -> code += codeGen.translateBuiltinFunc(expr, resultRegister)
+            is PtFunctionCall -> code += translate(expr, resultRegister, resultFpRegister)
+            is PtContainmentCheck -> code += translate(expr, resultRegister, resultFpRegister)
+            is PtRange,
+            is PtArray,
+            is PtString -> throw AssemblyError("range/arrayliteral/string should no longer occur as expression")
+            else -> throw AssemblyError("weird expression")
+        }
+        return code
+    }
+
+    private fun translate(check: PtContainmentCheck, resultRegister: Int, resultFpRegister: Int): IRCodeChunk {
+        val code = IRCodeChunk(check.position)
+        code += translateExpression(check.element, resultRegister, -1)   // load the element to check in resultRegister
+        val iterable = codeGen.symbolTable.flat.getValue(check.iterable.targetName) as StStaticVariable
+        when(iterable.dt) {
+            DataType.STR -> {
+                val call = PtFunctionCall(listOf("prog8_lib", "string_contains"), false, DataType.UBYTE, check.position)
+                call.children.add(check.element)
+                call.children.add(check.iterable)
+                code += translate(call, resultRegister, resultFpRegister)
+            }
+            DataType.ARRAY_UB, DataType.ARRAY_B -> {
+                val call = PtFunctionCall(listOf("prog8_lib", "bytearray_contains"), false, DataType.UBYTE, check.position)
+                call.children.add(check.element)
+                call.children.add(check.iterable)
+                call.children.add(PtNumber(DataType.UBYTE, iterable.length!!.toDouble(), iterable.position))
+                code += translate(call, resultRegister, resultFpRegister)
+            }
+            DataType.ARRAY_UW, DataType.ARRAY_W -> {
+                val call = PtFunctionCall(listOf("prog8_lib", "wordarray_contains"), false, DataType.UBYTE, check.position)
+                call.children.add(check.element)
+                call.children.add(check.iterable)
+                call.children.add(PtNumber(DataType.UBYTE, iterable.length!!.toDouble(), iterable.position))
+                code += translate(call, resultRegister, resultFpRegister)
+            }
+            DataType.ARRAY_F -> throw AssemblyError("containment check in float-array not supported")
+            else -> throw AssemblyError("weird iterable dt ${iterable.dt} for ${check.iterable.targetName}")
+        }
+        return code
+    }
+
+    private fun translate(arrayIx: PtArrayIndexer, resultRegister: Int, resultFpRegister: Int): IRCodeChunk {
+        val eltSize = codeGen.program.memsizer.memorySize(arrayIx.type)
+        val vmDt = codeGen.vmType(arrayIx.type)
+        val code = IRCodeChunk(arrayIx.position)
+        val idxReg = codeGen.vmRegisters.nextFree()
+        val arrayVarSymbol = arrayIx.variable.targetName.joinToString(".")
+
+        if(arrayIx.variable.type==DataType.UWORD) {
+            // indexing a pointer var instead of a real array or string
+            if(eltSize!=1)
+                throw AssemblyError("non-array var indexing requires bytes dt")
+            if(arrayIx.index.type!=DataType.UBYTE)
+                throw AssemblyError("non-array var indexing requires bytes index")
+            code += translateExpression(arrayIx.index, idxReg, -1)
+            code += IRCodeInstruction(Opcode.LOADIX, vmDt, reg1=resultRegister, reg2=idxReg, labelSymbol = arrayVarSymbol)
+            return code
+        }
+
+        if(arrayIx.index is PtNumber) {
+            val memOffset = ((arrayIx.index as PtNumber).number.toInt() * eltSize).toString()
+            if(vmDt==VmDataType.FLOAT)
+                code += IRCodeInstruction(Opcode.LOADM, VmDataType.FLOAT, fpReg1=resultFpRegister, labelSymbol = "$arrayVarSymbol+$memOffset")
+            else
+                code += IRCodeInstruction(Opcode.LOADM, vmDt, reg1=resultRegister, labelSymbol = "$arrayVarSymbol+$memOffset")
+        } else {
+            code += translateExpression(arrayIx.index, idxReg, -1)
+            if(eltSize>1)
+                code += codeGen.multiplyByConst(VmDataType.BYTE, idxReg, eltSize, arrayIx.position)
+            if(vmDt==VmDataType.FLOAT)
+                code += IRCodeInstruction(Opcode.LOADX, VmDataType.FLOAT, fpReg1 = resultFpRegister, reg1=idxReg, labelSymbol = arrayVarSymbol)
+            else
+                code += IRCodeInstruction(Opcode.LOADX, vmDt, reg1=resultRegister, reg2=idxReg, labelSymbol = arrayVarSymbol)
+        }
+        return code
+    }
+
+    private fun translate(expr: PtPrefix, resultRegister: Int): IRCodeChunk {
+        val code = IRCodeChunk(expr.position)
+        code += translateExpression(expr.value, resultRegister, -1)
+        val vmDt = codeGen.vmType(expr.type)
+        when(expr.operator) {
+            "+" -> { }
+            "-" -> {
+                code += IRCodeInstruction(Opcode.NEG, vmDt, reg1=resultRegister)
+            }
+            "~" -> {
+                val mask = if(vmDt==VmDataType.BYTE) 0x00ff else 0xffff
+                code += IRCodeInstruction(Opcode.XOR, vmDt, reg1=resultRegister, value=mask)
+            }
+            else -> throw AssemblyError("weird prefix operator")
+        }
+        return code
+    }
+
+    private fun translate(cast: PtTypeCast, predefinedResultRegister: Int, predefinedResultFpRegister: Int): IRCodeChunk {
+        val code = IRCodeChunk(cast.position)
+        if(cast.type==cast.value.type)
+            return code
+        val actualResultFpReg = if(predefinedResultFpRegister>=0) predefinedResultFpRegister else codeGen.vmRegisters.nextFreeFloat()
+        val actualResultReg = if(predefinedResultRegister>=0) predefinedResultRegister else codeGen.vmRegisters.nextFree()
+        if(cast.value.type==DataType.FLOAT) {
+            // a cast from float to integer, so evaluate the value into a float register first
+            code += translateExpression(cast.value, -1, actualResultFpReg)
+        }
+        else
+            code += translateExpression(cast.value, actualResultReg, -1)
+        when(cast.type) {
+            DataType.UBYTE -> {
+                when(cast.value.type) {
+                    DataType.BYTE, DataType.UWORD, DataType.WORD -> { /* just keep the LSB as it is */ }
+                    DataType.FLOAT -> code += IRCodeInstruction(Opcode.FTOUB, VmDataType.FLOAT, reg1=actualResultReg, fpReg1 = actualResultFpReg)
+                    else -> throw AssemblyError("weird cast value type")
+                }
+            }
+            DataType.BYTE -> {
+                when(cast.value.type) {
+                    DataType.UBYTE, DataType.UWORD, DataType.WORD -> { /* just keep the LSB as it is */ }
+                    DataType.FLOAT -> code += IRCodeInstruction(Opcode.FTOSB, VmDataType.FLOAT, reg1=actualResultReg, fpReg1 = actualResultFpReg)
+                    else -> throw AssemblyError("weird cast value type")
+                }
+            }
+            DataType.UWORD -> {
+                when(cast.value.type) {
+                    DataType.BYTE -> {
+                        // byte -> uword:   sign extend
+                        code += IRCodeInstruction(Opcode.EXTS, type = VmDataType.BYTE, reg1 = actualResultReg)
+                    }
+                    DataType.UBYTE -> {
+                        // ubyte -> uword:   sign extend
+                        code += IRCodeInstruction(Opcode.EXT, type = VmDataType.BYTE, reg1 = actualResultReg)
+                    }
+                    DataType.WORD -> { }
+                    DataType.FLOAT -> {
+                        code += IRCodeInstruction(Opcode.FTOUW, VmDataType.FLOAT, reg1=actualResultReg, fpReg1 = actualResultFpReg)
+                    }
+                    else -> throw AssemblyError("weird cast value type")
+                }
+            }
+            DataType.WORD -> {
+                when(cast.value.type) {
+                    DataType.BYTE -> {
+                        // byte -> word:   sign extend
+                        code += IRCodeInstruction(Opcode.EXTS, type = VmDataType.BYTE, reg1 = actualResultReg)
+                    }
+                    DataType.UBYTE -> {
+                        // byte -> word:   sign extend
+                        code += IRCodeInstruction(Opcode.EXT, type = VmDataType.BYTE, reg1 = actualResultReg)
+                    }
+                    DataType.UWORD -> { }
+                    DataType.FLOAT -> {
+                        code += IRCodeInstruction(Opcode.FTOSW, VmDataType.FLOAT, reg1=actualResultReg, fpReg1 = actualResultFpReg)
+                    }
+                    else -> throw AssemblyError("weird cast value type")
+                }
+            }
+            DataType.FLOAT -> {
+                code += when(cast.value.type) {
+                    DataType.UBYTE -> {
+                        IRCodeInstruction(Opcode.FFROMUB, VmDataType.FLOAT, reg1=actualResultReg, fpReg1 = actualResultFpReg)
+                    }
+                    DataType.BYTE -> {
+                        IRCodeInstruction(Opcode.FFROMSB, VmDataType.FLOAT, reg1=actualResultReg, fpReg1 = actualResultFpReg)
+                    }
+                    DataType.UWORD -> {
+                        IRCodeInstruction(Opcode.FFROMUW, VmDataType.FLOAT, reg1=actualResultReg, fpReg1 = actualResultFpReg)
+                    }
+                    DataType.WORD -> {
+                        IRCodeInstruction(Opcode.FFROMSW, VmDataType.FLOAT, reg1=actualResultReg, fpReg1 = actualResultFpReg)
+                    }
+                    else -> throw AssemblyError("weird cast value type")
+                }
+            }
+            else -> throw AssemblyError("weird cast type")
+        }
+        return code
+    }
+
+    private fun translate(binExpr: PtBinaryExpression, resultRegister: Int, resultFpRegister: Int): IRCodeChunk {
+        val vmDt = codeGen.vmType(binExpr.left.type)
+        val signed = binExpr.left.type in SignedDatatypes
+        return when(binExpr.operator) {
+            "+" -> operatorPlus(binExpr, vmDt, resultRegister, resultFpRegister)
+            "-" -> operatorMinus(binExpr, vmDt, resultRegister, resultFpRegister)
+            "*" -> operatorMultiply(binExpr, vmDt, resultRegister, resultFpRegister)
+            "/" -> operatorDivide(binExpr, vmDt, resultRegister, resultFpRegister, signed)
+            "%" -> operatorModulo(binExpr, vmDt, resultRegister)
+            "|" -> operatorOr(binExpr, vmDt, resultRegister)
+            "&" -> operatorAnd(binExpr, vmDt, resultRegister)
+            "^" -> operatorXor(binExpr, vmDt, resultRegister)
+            "<<" -> operatorShiftLeft(binExpr, vmDt, resultRegister)
+            ">>" -> operatorShiftRight(binExpr, vmDt, resultRegister, signed)
+            "==" -> operatorEquals(binExpr, vmDt, resultRegister, false)
+            "!=" -> operatorEquals(binExpr, vmDt, resultRegister, true)
+            "<" -> operatorLessThan(binExpr, vmDt, resultRegister, signed, false)
+            ">" -> operatorGreaterThan(binExpr, vmDt, resultRegister, signed, false)
+            "<=" -> operatorLessThan(binExpr, vmDt, resultRegister, signed, true)
+            ">=" -> operatorGreaterThan(binExpr, vmDt, resultRegister, signed, true)
+            else -> throw AssemblyError("weird operator ${binExpr.operator}")
+        }
+    }
+
+    private fun operatorGreaterThan(
+        binExpr: PtBinaryExpression,
+        vmDt: VmDataType,
+        resultRegister: Int,
+        signed: Boolean,
+        greaterEquals: Boolean
+    ): IRCodeChunk {
+        val code = IRCodeChunk(binExpr.position)
+        if(vmDt==VmDataType.FLOAT) {
+            val leftFpReg = codeGen.vmRegisters.nextFreeFloat()
+            val rightFpReg = codeGen.vmRegisters.nextFreeFloat()
+            val zeroRegister = codeGen.vmRegisters.nextFree()
+            code += translateExpression(binExpr.left, -1, leftFpReg)
+            code += translateExpression(binExpr.right, -1, rightFpReg)
+            code += IRCodeInstruction(Opcode.FCOMP, VmDataType.FLOAT, reg1=resultRegister, fpReg1 = leftFpReg, fpReg2 = rightFpReg)
+            code += IRCodeInstruction(Opcode.LOAD, VmDataType.BYTE, reg1=zeroRegister, value=0)
+            val ins = if (signed) {
+                if (greaterEquals) Opcode.SGES else Opcode.SGTS
+            } else {
+                if (greaterEquals) Opcode.SGE else Opcode.SGT
+            }
+            code += IRCodeInstruction(ins, VmDataType.BYTE, reg1 = resultRegister, reg2 = zeroRegister)
+        } else {
+            if(binExpr.left.type==DataType.STR && binExpr.right.type==DataType.STR) {
+                val comparisonCall = PtFunctionCall(listOf("prog8_lib", "string_compare"), false, DataType.BYTE, Position.DUMMY)
+                comparisonCall.children.add(binExpr.left)
+                comparisonCall.children.add(binExpr.right)
+                code += translate(comparisonCall, resultRegister, -1)
+                val zeroRegister = codeGen.vmRegisters.nextFree()
+                code += IRCodeInstruction(Opcode.LOAD, VmDataType.BYTE, reg1=zeroRegister, value=0)
+                code += if(greaterEquals)
+                    IRCodeInstruction(Opcode.SGES, VmDataType.BYTE, reg1=resultRegister, reg2=zeroRegister)
+                else
+                    IRCodeInstruction(Opcode.SGTS, VmDataType.BYTE, reg1=resultRegister, reg2=zeroRegister)
+            } else {
+                val rightResultReg = codeGen.vmRegisters.nextFree()
+                code += translateExpression(binExpr.left, resultRegister, -1)
+                code += translateExpression(binExpr.right, rightResultReg, -1)
+                val ins = if (signed) {
+                    if (greaterEquals) Opcode.SGES else Opcode.SGTS
+                } else {
+                    if (greaterEquals) Opcode.SGE else Opcode.SGT
+                }
+                code += IRCodeInstruction(ins, vmDt, reg1 = resultRegister, reg2 = rightResultReg)
+            }
+        }
+        return code
+    }
+
+    private fun operatorLessThan(
+        binExpr: PtBinaryExpression,
+        vmDt: VmDataType,
+        resultRegister: Int,
+        signed: Boolean,
+        lessEquals: Boolean
+    ): IRCodeChunk {
+        val code = IRCodeChunk(binExpr.position)
+        if(vmDt==VmDataType.FLOAT) {
+            val leftFpReg = codeGen.vmRegisters.nextFreeFloat()
+            val rightFpReg = codeGen.vmRegisters.nextFreeFloat()
+            val zeroRegister = codeGen.vmRegisters.nextFree()
+            code += translateExpression(binExpr.left, -1, leftFpReg)
+            code += translateExpression(binExpr.right, -1, rightFpReg)
+            code += IRCodeInstruction(Opcode.FCOMP, VmDataType.FLOAT, reg1=resultRegister, fpReg1 = leftFpReg, fpReg2 = rightFpReg)
+            code += IRCodeInstruction(Opcode.LOAD, VmDataType.BYTE, reg1=zeroRegister, value=0)
+            val ins = if (signed) {
+                if (lessEquals) Opcode.SLES else Opcode.SLTS
+            } else {
+                if (lessEquals) Opcode.SLE else Opcode.SLT
+            }
+            code += IRCodeInstruction(ins, VmDataType.BYTE, reg1 = resultRegister, reg2 = zeroRegister)
+        } else {
+            if(binExpr.left.type==DataType.STR && binExpr.right.type==DataType.STR) {
+                val comparisonCall = PtFunctionCall(listOf("prog8_lib", "string_compare"), false, DataType.BYTE, Position.DUMMY)
+                comparisonCall.children.add(binExpr.left)
+                comparisonCall.children.add(binExpr.right)
+                code += translate(comparisonCall, resultRegister, -1)
+                val zeroRegister = codeGen.vmRegisters.nextFree()
+                code += IRCodeInstruction(Opcode.LOAD, VmDataType.BYTE, reg1=zeroRegister, value=0)
+                code += if(lessEquals)
+                    IRCodeInstruction(Opcode.SLES, VmDataType.BYTE, reg1=resultRegister, reg2=zeroRegister)
+                else
+                    IRCodeInstruction(Opcode.SLTS, VmDataType.BYTE, reg1=resultRegister, reg2=zeroRegister)
+            } else {
+                val rightResultReg = codeGen.vmRegisters.nextFree()
+                code += translateExpression(binExpr.left, resultRegister, -1)
+                code += translateExpression(binExpr.right, rightResultReg, -1)
+                val ins = if (signed) {
+                    if (lessEquals) Opcode.SLES else Opcode.SLTS
+                } else {
+                    if (lessEquals) Opcode.SLE else Opcode.SLT
+                }
+                code += IRCodeInstruction(ins, vmDt, reg1 = resultRegister, reg2 = rightResultReg)
+            }
+        }
+        return code
+    }
+
+    private fun operatorEquals(binExpr: PtBinaryExpression, vmDt: VmDataType, resultRegister: Int, notEquals: Boolean): IRCodeChunk {
+        val code = IRCodeChunk(binExpr.position)
+        if(vmDt==VmDataType.FLOAT) {
+            val leftFpReg = codeGen.vmRegisters.nextFreeFloat()
+            val rightFpReg = codeGen.vmRegisters.nextFreeFloat()
+            code += translateExpression(binExpr.left, -1, leftFpReg)
+            code += translateExpression(binExpr.right, -1, rightFpReg)
+            if (notEquals) {
+                code += IRCodeInstruction(Opcode.FCOMP, VmDataType.FLOAT, reg1=resultRegister, fpReg1 = leftFpReg, fpReg2 = rightFpReg)
+            } else {
+                val label = codeGen.createLabelName()
+                val valueReg = codeGen.vmRegisters.nextFree()
+                code += IRCodeInstruction(Opcode.LOAD, VmDataType.BYTE, reg1=resultRegister, value=1)
+                code += IRCodeInstruction(Opcode.FCOMP, VmDataType.FLOAT, reg1=valueReg, fpReg1 = leftFpReg, fpReg2 = rightFpReg)
+                code += IRCodeInstruction(Opcode.BZ, VmDataType.BYTE, reg1=valueReg, labelSymbol = label)
+                code += IRCodeInstruction(Opcode.LOAD, VmDataType.BYTE, reg1=resultRegister, value=0)
+                code += IRCodeLabel(label)
+            }
+        } else {
+            if(binExpr.left.type==DataType.STR && binExpr.right.type==DataType.STR) {
+                val comparisonCall = PtFunctionCall(listOf("prog8_lib", "string_compare"), false, DataType.BYTE, Position.DUMMY)
+                comparisonCall.children.add(binExpr.left)
+                comparisonCall.children.add(binExpr.right)
+                code += translate(comparisonCall, resultRegister, -1)
+                if(!notEquals)
+                    code += IRCodeInstruction(Opcode.INV, vmDt, reg1=resultRegister)
+                code += IRCodeInstruction(Opcode.AND, vmDt, reg1=resultRegister, value=1)
+            } else {
+                val rightResultReg = codeGen.vmRegisters.nextFree()
+                code += translateExpression(binExpr.left, resultRegister, -1)
+                code += translateExpression(binExpr.right, rightResultReg, -1)
+                val opcode = if (notEquals) Opcode.SNE else Opcode.SEQ
+                code += IRCodeInstruction(opcode, vmDt, reg1 = resultRegister, reg2 = rightResultReg)
+            }
+        }
+        return code
+    }
+
+    private fun operatorShiftRight(binExpr: PtBinaryExpression, vmDt: VmDataType, resultRegister: Int, signed: Boolean): IRCodeChunk {
+        val code = IRCodeChunk(binExpr.position)
+        if(codeGen.isOne(binExpr.right)) {
+            code += translateExpression(binExpr.left, resultRegister, -1)
+            val opc = if (signed) Opcode.ASR else Opcode.LSR
+            code += IRCodeInstruction(opc, vmDt, reg1 = resultRegister)
+        } else {
+            val rightResultReg = codeGen.vmRegisters.nextFree()
+            code += translateExpression(binExpr.left, resultRegister, -1)
+            code += translateExpression(binExpr.right, rightResultReg, -1)
+            val opc = if (signed) Opcode.ASRN else Opcode.LSRN
+            code += IRCodeInstruction(opc, vmDt, reg1 = resultRegister, reg2 = rightResultReg)
+        }
+        return code
+    }
+
+    internal fun operatorShiftRightInplace(knownAddress: Int?, symbol: String?, vmDt: VmDataType, signed: Boolean, operand: PtExpression): IRCodeChunk {
+        val code = IRCodeChunk(operand.position)
+        if(codeGen.isOne(operand)) {
+            val opc = if (signed) Opcode.ASRM else Opcode.LSRM
+            code += if(knownAddress!=null)
+                IRCodeInstruction(opc, vmDt, value=knownAddress)
+            else
+                IRCodeInstruction(opc, vmDt, labelSymbol = symbol)
+        } else {
+            val operandReg = codeGen.vmRegisters.nextFree()
+            code += translateExpression(operand, operandReg, -1)
+            val opc = if (signed) Opcode.ASRNM else Opcode.LSRNM
+            code += if(knownAddress!=null)
+                IRCodeInstruction(opc, vmDt, reg1 = operandReg, value=knownAddress)
+            else
+                IRCodeInstruction(opc, vmDt, reg1 = operandReg, labelSymbol = symbol)
+        }
+        return code
+    }
+
+    private fun operatorShiftLeft(binExpr: PtBinaryExpression, vmDt: VmDataType, resultRegister: Int): IRCodeChunk {
+        val code = IRCodeChunk(binExpr.position)
+        if(codeGen.isOne(binExpr.right)){
+            code += translateExpression(binExpr.left, resultRegister, -1)
+            code += IRCodeInstruction(Opcode.LSL, vmDt, reg1=resultRegister)
+        } else {
+            val rightResultReg = codeGen.vmRegisters.nextFree()
+            code += translateExpression(binExpr.left, resultRegister, -1)
+            code += translateExpression(binExpr.right, rightResultReg, -1)
+            code += IRCodeInstruction(Opcode.LSLN, vmDt, reg1=resultRegister, rightResultReg)
+        }
+        return code
+    }
+
+    internal fun operatorShiftLeftInplace(knownAddress: Int?, symbol: String?, vmDt: VmDataType, operand: PtExpression): IRCodeChunk {
+        val code = IRCodeChunk(operand.position)
+        if(codeGen.isOne(operand)){
+            code += if(knownAddress!=null)
+                IRCodeInstruction(Opcode.LSLM, vmDt, value=knownAddress)
+            else
+                IRCodeInstruction(Opcode.LSLM, vmDt, labelSymbol = symbol)
+        } else {
+            val operandReg = codeGen.vmRegisters.nextFree()
+            code += translateExpression(operand, operandReg, -1)
+            code += if(knownAddress!=null)
+                IRCodeInstruction(Opcode.LSLNM, vmDt, reg1=operandReg, value=knownAddress)
+            else
+                IRCodeInstruction(Opcode.LSLNM, vmDt, reg1=operandReg, labelSymbol = symbol)
+        }
+        return code
+    }
+
+    private fun operatorXor(binExpr: PtBinaryExpression, vmDt: VmDataType, resultRegister: Int): IRCodeChunk {
+        val code = IRCodeChunk(binExpr.position)
+        if(binExpr.right is PtNumber) {
+            code += translateExpression(binExpr.left, resultRegister, -1)
+            code += IRCodeInstruction(Opcode.XOR, vmDt, reg1 = resultRegister, value=(binExpr.right as PtNumber).number.toInt())
+        } else {
+            val rightResultReg = codeGen.vmRegisters.nextFree()
+            code += translateExpression(binExpr.left, resultRegister, -1)
+            code += translateExpression(binExpr.right, rightResultReg, -1)
+            code += IRCodeInstruction(Opcode.XORR, vmDt, reg1 = resultRegister, reg2 = rightResultReg)
+        }
+        return code
+    }
+
+    internal fun operatorXorInplace(knownAddress: Int?, symbol: String?, vmDt: VmDataType, operand: PtExpression): IRCodeChunk {
+        val code = IRCodeChunk(operand.position)
+        val operandReg = codeGen.vmRegisters.nextFree()
+        code += translateExpression(operand, operandReg, -1)
+        code += if(knownAddress!=null)
+            IRCodeInstruction(Opcode.XORM, vmDt, reg1=operandReg, value = knownAddress)
+        else
+            IRCodeInstruction(Opcode.XORM, vmDt, reg1=operandReg, labelSymbol = symbol)
+        return code
+    }
+
+    private fun operatorAnd(binExpr: PtBinaryExpression, vmDt: VmDataType, resultRegister: Int): IRCodeChunk {
+        val code = IRCodeChunk(binExpr.position)
+        if(binExpr.right is PtNumber) {
+            code += translateExpression(binExpr.left, resultRegister, -1)
+            code += IRCodeInstruction(Opcode.AND, vmDt, reg1 = resultRegister, value=(binExpr.right as PtNumber).number.toInt())
+        } else {
+            val rightResultReg = codeGen.vmRegisters.nextFree()
+            code += translateExpression(binExpr.left, resultRegister, -1)
+            code += translateExpression(binExpr.right, rightResultReg, -1)
+            code += IRCodeInstruction(Opcode.ANDR, vmDt, reg1 = resultRegister, reg2 = rightResultReg)
+        }
+        return code
+    }
+
+    internal  fun operatorAndInplace(knownAddress: Int?, symbol: String?, vmDt: VmDataType, operand: PtExpression): IRCodeChunk {
+        val code = IRCodeChunk(operand.position)
+        val operandReg = codeGen.vmRegisters.nextFree()
+        code += translateExpression(operand, operandReg, -1)
+        code += if(knownAddress!=null)
+            IRCodeInstruction(Opcode.ANDM, vmDt, reg1=operandReg, value=knownAddress)
+        else
+            IRCodeInstruction(Opcode.ANDM, vmDt, reg1=operandReg, labelSymbol = symbol)
+        return code
+    }
+
+    private fun operatorOr(binExpr: PtBinaryExpression, vmDt: VmDataType, resultRegister: Int): IRCodeChunk {
+        val code = IRCodeChunk(binExpr.position)
+        if(binExpr.right is PtNumber) {
+            code += translateExpression(binExpr.left, resultRegister, -1)
+            code += IRCodeInstruction(Opcode.OR, vmDt, reg1 = resultRegister, value=(binExpr.right as PtNumber).number.toInt())
+        } else {
+            val rightResultReg = codeGen.vmRegisters.nextFree()
+            code += translateExpression(binExpr.left, resultRegister, -1)
+            code += translateExpression(binExpr.right, rightResultReg, -1)
+            code += IRCodeInstruction(Opcode.ORR, vmDt, reg1 = resultRegister, reg2 = rightResultReg)
+        }
+        return code
+    }
+
+    internal fun operatorOrInplace(knownAddress: Int?, symbol: String?, vmDt: VmDataType, operand: PtExpression): IRCodeChunk {
+        val code = IRCodeChunk(operand.position)
+        val operandReg = codeGen.vmRegisters.nextFree()
+        code += translateExpression(operand, operandReg, -1)
+        code += if(knownAddress!=null)
+            IRCodeInstruction(Opcode.ORM, vmDt, reg1=operandReg, value = knownAddress)
+        else
+            IRCodeInstruction(Opcode.ORM, vmDt, reg1=operandReg, labelSymbol = symbol)
+        return code
+    }
+
+    private fun operatorModulo(binExpr: PtBinaryExpression, vmDt: VmDataType, resultRegister: Int): IRCodeChunk {
+        if(vmDt==VmDataType.FLOAT)
+            throw IllegalArgumentException("floating-point modulo not supported")
+        val code = IRCodeChunk(binExpr.position)
+        val rightResultReg = codeGen.vmRegisters.nextFree()
+        if(binExpr.right is PtNumber) {
+            code += translateExpression(binExpr.left, resultRegister, -1)
+            code += IRCodeInstruction(Opcode.MOD, vmDt, reg1 = resultRegister, value=(binExpr.right as PtNumber).number.toInt())
+        } else {
+            code += translateExpression(binExpr.left, resultRegister, -1)
+            code += translateExpression(binExpr.right, rightResultReg, -1)
+            code += IRCodeInstruction(Opcode.MODR, vmDt, reg1 = resultRegister, reg2 = rightResultReg)
+        }
+        return code
+    }
+
+    private fun operatorDivide(binExpr: PtBinaryExpression,
+                               vmDt: VmDataType,
+                               resultRegister: Int,
+                               resultFpRegister: Int,
+                               signed: Boolean): IRCodeChunk {
+        val code = IRCodeChunk(binExpr.position)
+        val constFactorRight = binExpr.right as? PtNumber
+        if(vmDt==VmDataType.FLOAT) {
+            if(constFactorRight!=null && constFactorRight.type!=DataType.FLOAT) {
+                code += translateExpression(binExpr.left, -1, resultFpRegister)
+                val factor = constFactorRight.number.toFloat()
+                code += codeGen.divideByConstFloat(resultFpRegister, factor, binExpr.position)
+            } else {
+                val rightResultFpReg = codeGen.vmRegisters.nextFreeFloat()
+                code += translateExpression(binExpr.left, -1, resultFpRegister)
+                code += translateExpression(binExpr.right, -1, rightResultFpReg)
+                code += if(signed)
+                    IRCodeInstruction(Opcode.DIVSR, vmDt, fpReg1 = resultFpRegister, fpReg2=rightResultFpReg)
+                else
+                    IRCodeInstruction(Opcode.DIVR, vmDt, fpReg1 = resultFpRegister, fpReg2=rightResultFpReg)
+            }
+        } else {
+            if(constFactorRight!=null && constFactorRight.type!=DataType.FLOAT) {
+                code += translateExpression(binExpr.left, resultRegister, -1)
+                val factor = constFactorRight.number.toInt()
+                code += codeGen.divideByConst(vmDt, resultRegister, factor, signed, binExpr.position)
+            } else {
+                val rightResultReg = codeGen.vmRegisters.nextFree()
+                if(binExpr.right is PtNumber) {
+                    code += translateExpression(binExpr.left, resultRegister, -1)
+                    code += if (signed)
+                        IRCodeInstruction(Opcode.DIVS, vmDt, reg1 = resultRegister, value=(binExpr.right as PtNumber).number.toInt())
+                    else
+                        IRCodeInstruction(Opcode.DIV, vmDt, reg1 = resultRegister, value=(binExpr.right as PtNumber).number.toInt())
+                } else {
+                    code += translateExpression(binExpr.left, resultRegister, -1)
+                    code += translateExpression(binExpr.right, rightResultReg, -1)
+                    code += if (signed)
+                        IRCodeInstruction(Opcode.DIVSR, vmDt, reg1 = resultRegister, reg2 = rightResultReg)
+                    else
+                        IRCodeInstruction(Opcode.DIVR, vmDt, reg1 = resultRegister, reg2 = rightResultReg)
+                }
+            }
+        }
+        return code
+    }
+
+    internal fun operatorDivideInplace(knownAddress: Int?, symbol: String?, vmDt: VmDataType, signed: Boolean, operand: PtExpression): IRCodeChunk {
+        val code = IRCodeChunk(operand.position)
+        val constFactorRight = operand as? PtNumber
+        if(vmDt==VmDataType.FLOAT) {
+            if(constFactorRight!=null && constFactorRight.type!=DataType.FLOAT) {
+                val factor = constFactorRight.number.toFloat()
+                code += codeGen.divideByConstFloatInplace(knownAddress, symbol, factor, operand.position)
+            } else {
+                val operandFpReg = codeGen.vmRegisters.nextFreeFloat()
+                code += translateExpression(operand, -1, operandFpReg)
+                code += if(signed) {
+                    if(knownAddress!=null)
+                        IRCodeInstruction(Opcode.DIVSM, vmDt, fpReg1 = operandFpReg, value = knownAddress)
+                    else
+                        IRCodeInstruction(Opcode.DIVSM, vmDt, fpReg1 = operandFpReg, labelSymbol = symbol)
+                }
+                else {
+                    if(knownAddress!=null)
+                        IRCodeInstruction(Opcode.DIVM, vmDt, fpReg1 = operandFpReg, value = knownAddress)
+                    else
+                        IRCodeInstruction(Opcode.DIVM, vmDt, fpReg1 = operandFpReg, labelSymbol = symbol)
+                }
+            }
+        } else {
+            if(constFactorRight!=null && constFactorRight.type!=DataType.FLOAT) {
+                val factor = constFactorRight.number.toInt()
+                code += codeGen.divideByConstInplace(vmDt, knownAddress, symbol, factor, signed, operand.position)
+            } else {
+                val operandReg = codeGen.vmRegisters.nextFree()
+                code += translateExpression(operand, operandReg, -1)
+                code += if(signed) {
+                    if(knownAddress!=null)
+                        IRCodeInstruction(Opcode.DIVSM, vmDt, reg1 = operandReg, value = knownAddress)
+                    else
+                        IRCodeInstruction(Opcode.DIVSM, vmDt, reg1 = operandReg, labelSymbol = symbol)
+                }
+                else {
+                    if(knownAddress!=null)
+                        IRCodeInstruction(Opcode.DIVM, vmDt, reg1 = operandReg, value = knownAddress)
+                    else
+                        IRCodeInstruction(Opcode.DIVM, vmDt, reg1 = operandReg, labelSymbol = symbol)
+                }
+            }
+        }
+        return code
+    }
+
+    private fun operatorMultiply(binExpr: PtBinaryExpression, vmDt: VmDataType, resultRegister: Int, resultFpRegister: Int): IRCodeChunk {
+        val code = IRCodeChunk(binExpr.position)
+        val constFactorLeft = binExpr.left as? PtNumber
+        val constFactorRight = binExpr.right as? PtNumber
+        if(vmDt==VmDataType.FLOAT) {
+            if(constFactorLeft!=null) {
+                code += translateExpression(binExpr.right, -1, resultFpRegister)
+                val factor = constFactorLeft.number.toFloat()
+                code += codeGen.multiplyByConstFloat(resultFpRegister, factor, constFactorLeft.position)
+            } else if(constFactorRight!=null) {
+                code += translateExpression(binExpr.left, -1, resultFpRegister)
+                val factor = constFactorRight.number.toFloat()
+                code += codeGen.multiplyByConstFloat(resultFpRegister, factor, constFactorRight.position)
+            } else {
+                val rightResultFpReg = codeGen.vmRegisters.nextFreeFloat()
+                code += translateExpression(binExpr.left, -1, resultFpRegister)
+                code += translateExpression(binExpr.right, -1, rightResultFpReg)
+                code += IRCodeInstruction(Opcode.MULR, vmDt, fpReg1 = resultFpRegister, fpReg2 = rightResultFpReg)
+            }
+        } else {
+            if(constFactorLeft!=null && constFactorLeft.type!=DataType.FLOAT) {
+                code += translateExpression(binExpr.right, resultRegister, -1)
+                val factor = constFactorLeft.number.toInt()
+                code += codeGen.multiplyByConst(vmDt, resultRegister, factor, constFactorLeft.position)
+            } else if(constFactorRight!=null && constFactorRight.type!=DataType.FLOAT) {
+                code += translateExpression(binExpr.left, resultRegister, -1)
+                val factor = constFactorRight.number.toInt()
+                code += codeGen.multiplyByConst(vmDt, resultRegister, factor, constFactorRight.position)
+            } else {
+                val rightResultReg = codeGen.vmRegisters.nextFree()
+                code += translateExpression(binExpr.left, resultRegister, -1)
+                code += translateExpression(binExpr.right, rightResultReg, -1)
+                code += IRCodeInstruction(Opcode.MULR, vmDt, reg1 = resultRegister, reg2 = rightResultReg)
+            }
+        }
+        return code
+    }
+
+    internal fun operatorMultiplyInplace(knownAddress: Int?, symbol: String?, vmDt: VmDataType, operand: PtExpression): IRCodeChunk {
+        val code = IRCodeChunk(operand.position)
+        val constFactorRight = operand as? PtNumber
+        if(vmDt==VmDataType.FLOAT) {
+            if(constFactorRight!=null) {
+                val factor = constFactorRight.number.toFloat()
+                code += codeGen.multiplyByConstFloatInplace(knownAddress, symbol, factor, constFactorRight.position)
+            } else {
+                val operandFpReg = codeGen.vmRegisters.nextFreeFloat()
+                code += translateExpression(operand, -1, operandFpReg)
+                code += if(knownAddress!=null)
+                    IRCodeInstruction(Opcode.MULM, vmDt, fpReg1 = operandFpReg, value = knownAddress)
+                else
+                    IRCodeInstruction(Opcode.MULM, vmDt, fpReg1 = operandFpReg, labelSymbol = symbol)
+            }
+        } else {
+            if(constFactorRight!=null && constFactorRight.type!=DataType.FLOAT) {
+                val factor = constFactorRight.number.toInt()
+                code += codeGen.multiplyByConstInplace(vmDt, knownAddress, symbol, factor, constFactorRight.position)
+            } else {
+                val operandReg = codeGen.vmRegisters.nextFree()
+                code += translateExpression(operand, operandReg, -1)
+                code += if(knownAddress!=null)
+                    IRCodeInstruction(Opcode.MULM, vmDt, reg1=operandReg, value = knownAddress)
+                else
+                    IRCodeInstruction(Opcode.MULM, vmDt, reg1=operandReg, labelSymbol = symbol)
+            }
+        }
+        return code
+    }
+
+    private fun operatorMinus(binExpr: PtBinaryExpression, vmDt: VmDataType, resultRegister: Int, resultFpRegister: Int): IRCodeChunk {
+        val code = IRCodeChunk(binExpr.position)
+        if(vmDt==VmDataType.FLOAT) {
+            if((binExpr.right as? PtNumber)?.number==1.0) {
+                code += translateExpression(binExpr.left, -1, resultFpRegister)
+                code += IRCodeInstruction(Opcode.DEC, vmDt, fpReg1 = resultFpRegister)
+            }
+            else {
+                if(binExpr.right is PtNumber) {
+                    code += translateExpression(binExpr.left, -1, resultFpRegister)
+                    code += IRCodeInstruction(Opcode.SUB, vmDt, fpReg1 = resultFpRegister, fpValue = (binExpr.right as PtNumber).number.toFloat())
+                } else {
+                    val rightResultFpReg = codeGen.vmRegisters.nextFreeFloat()
+                    code += translateExpression(binExpr.left, -1, resultFpRegister)
+                    code += translateExpression(binExpr.right, -1, rightResultFpReg)
+                    code += IRCodeInstruction(Opcode.SUBR, vmDt, fpReg1 = resultFpRegister, fpReg2 = rightResultFpReg)
+                }
+            }
+        } else {
+            if((binExpr.right as? PtNumber)?.number==1.0) {
+                code += translateExpression(binExpr.left, resultRegister, -1)
+                code += IRCodeInstruction(Opcode.DEC, vmDt, reg1=resultRegister)
+            }
+            else {
+                if(binExpr.right is PtNumber) {
+                    code += translateExpression(binExpr.left, resultRegister, -1)
+                    code += IRCodeInstruction(Opcode.SUB, vmDt, reg1 = resultRegister, value = (binExpr.right as PtNumber).number.toInt())
+                } else {
+                    val rightResultReg = codeGen.vmRegisters.nextFree()
+                    code += translateExpression(binExpr.left, resultRegister, -1)
+                    code += translateExpression(binExpr.right, rightResultReg, -1)
+                    code += IRCodeInstruction(Opcode.SUBR, vmDt, reg1 = resultRegister, reg2 = rightResultReg)
+                }
+            }
+        }
+        return code
+    }
+
+    internal fun operatorMinusInplace(knownAddress: Int?, symbol: String?, vmDt: VmDataType, operand: PtExpression): IRCodeChunk {
+        val code = IRCodeChunk(operand.position)
+        if(vmDt==VmDataType.FLOAT) {
+            if((operand as? PtNumber)?.number==1.0) {
+                code += if(knownAddress!=null)
+                    IRCodeInstruction(Opcode.DECM, vmDt, value=knownAddress)
+                else
+                    IRCodeInstruction(Opcode.DECM, vmDt, labelSymbol = symbol)
+            }
+            else {
+                val operandFpReg = codeGen.vmRegisters.nextFreeFloat()
+                code += translateExpression(operand, -1, operandFpReg)
+                code += if(knownAddress!=null)
+                    IRCodeInstruction(Opcode.SUBM, vmDt, fpReg1=operandFpReg, value=knownAddress)
+                else
+                    IRCodeInstruction(Opcode.SUBM, vmDt, fpReg1=operandFpReg, labelSymbol = symbol)
+            }
+        } else {
+            if((operand as? PtNumber)?.number==1.0) {
+                code += if(knownAddress!=null)
+                    IRCodeInstruction(Opcode.DECM, vmDt, value=knownAddress)
+                else
+                    IRCodeInstruction(Opcode.DECM, vmDt, labelSymbol = symbol)
+            }
+            else {
+                val operandReg = codeGen.vmRegisters.nextFree()
+                code += translateExpression(operand, operandReg, -1)
+                code += if(knownAddress!=null)
+                    IRCodeInstruction(Opcode.SUBM, vmDt, reg1=operandReg, value = knownAddress)
+                else
+                    IRCodeInstruction(Opcode.SUBM, vmDt, reg1=operandReg, labelSymbol = symbol)
+            }
+        }
+        return code
+    }
+
+    private fun operatorPlus(binExpr: PtBinaryExpression, vmDt: VmDataType, resultRegister: Int, resultFpRegister: Int): IRCodeChunk {
+        val code = IRCodeChunk(binExpr.position)
+        if(vmDt==VmDataType.FLOAT) {
+            if((binExpr.left as? PtNumber)?.number==1.0) {
+                code += translateExpression(binExpr.right, -1, resultFpRegister)
+                code += IRCodeInstruction(Opcode.INC, vmDt, fpReg1=resultFpRegister)
+            }
+            else if((binExpr.right as? PtNumber)?.number==1.0) {
+                code += translateExpression(binExpr.left, -1, resultFpRegister)
+                code += IRCodeInstruction(Opcode.INC, vmDt, fpReg1=resultFpRegister)
+            }
+            else {
+                if(binExpr.right is PtNumber) {
+                    code += translateExpression(binExpr.left, -1, resultFpRegister)
+                    code += IRCodeInstruction(Opcode.ADD, vmDt, fpReg1 = resultFpRegister, fpValue = (binExpr.right as PtNumber).number.toFloat())
+                } else {
+                    val rightResultFpReg = codeGen.vmRegisters.nextFreeFloat()
+                    code += translateExpression(binExpr.left, -1, resultFpRegister)
+                    code += translateExpression(binExpr.right, -1, rightResultFpReg)
+                    code += IRCodeInstruction(Opcode.ADDR, vmDt, fpReg1 = resultFpRegister, fpReg2 = rightResultFpReg)
+                }
+            }
+        } else {
+            if((binExpr.left as? PtNumber)?.number==1.0) {
+                code += translateExpression(binExpr.right, resultRegister, -1)
+                code += IRCodeInstruction(Opcode.INC, vmDt, reg1=resultRegister)
+            }
+            else if((binExpr.right as? PtNumber)?.number==1.0) {
+                code += translateExpression(binExpr.left, resultRegister, -1)
+                code += IRCodeInstruction(Opcode.INC, vmDt, reg1=resultRegister)
+            }
+            else {
+                if(binExpr.right is PtNumber) {
+                    code += translateExpression(binExpr.left, resultRegister, -1)
+                    code += IRCodeInstruction(Opcode.ADD, vmDt, reg1 = resultRegister, value=(binExpr.right as PtNumber).number.toInt())
+                } else {
+                    val rightResultReg = codeGen.vmRegisters.nextFree()
+                    code += translateExpression(binExpr.left, resultRegister, -1)
+                    code += translateExpression(binExpr.right, rightResultReg, -1)
+                    code += IRCodeInstruction(Opcode.ADDR, vmDt, reg1 = resultRegister, reg2 = rightResultReg)
+                }
+            }
+        }
+        return code
+    }
+
+    internal fun operatorPlusInplace(knownAddress: Int?, symbol: String?, vmDt: VmDataType, operand: PtExpression): IRCodeChunk {
+        val code = IRCodeChunk(operand.position)
+        if(vmDt==VmDataType.FLOAT) {
+            if((operand as? PtNumber)?.number==1.0) {
+                code += if(knownAddress!=null)
+                    IRCodeInstruction(Opcode.INCM, vmDt, value = knownAddress)
+                else
+                    IRCodeInstruction(Opcode.INCM, vmDt, labelSymbol = symbol)
+            }
+            else {
+                val operandFpReg = codeGen.vmRegisters.nextFreeFloat()
+                code += translateExpression(operand, -1, operandFpReg)
+                code += if(knownAddress!=null)
+                    IRCodeInstruction(Opcode.ADDM, vmDt, fpReg1=operandFpReg, value = knownAddress)
+                else
+                    IRCodeInstruction(Opcode.ADDM, vmDt, fpReg1=operandFpReg, labelSymbol = symbol)
+            }
+        } else {
+            if((operand as? PtNumber)?.number==1.0) {
+                code += if(knownAddress!=null)
+                    IRCodeInstruction(Opcode.INCM, vmDt, value = knownAddress)
+                else
+                    IRCodeInstruction(Opcode.INCM, vmDt, labelSymbol = symbol)
+            }
+            else {
+                val operandReg = codeGen.vmRegisters.nextFree()
+                code += translateExpression(operand, operandReg, -1)
+                code += if(knownAddress!=null)
+                    IRCodeInstruction(Opcode.ADDM, vmDt, reg1=operandReg, value=knownAddress)
+                else
+                    IRCodeInstruction(Opcode.ADDM, vmDt, reg1=operandReg, labelSymbol = symbol)
+            }
+        }
+        return code
+    }
+
+    fun translate(fcall: PtFunctionCall, resultRegister: Int, resultFpRegister: Int): IRCodeChunk {
+        when (val callTarget = codeGen.symbolTable.flat.getValue(fcall.functionName)) {
+            is StSub -> {
+                val code = IRCodeChunk(fcall.position)
+                for ((arg, parameter) in fcall.args.zip(callTarget.parameters)) {
+                    val paramDt = codeGen.vmType(parameter.type)
+                    val symbol = (fcall.functionName + parameter.name).joinToString(".")
+                    if(codeGen.isZero(arg)) {
+                        code += IRCodeInstruction(Opcode.STOREZM, paramDt, labelSymbol = symbol)
+                    } else {
+                        if (paramDt == VmDataType.FLOAT) {
+                            val argFpReg = codeGen.vmRegisters.nextFreeFloat()
+                            code += translateExpression(arg, -1, argFpReg)
+                            code += IRCodeInstruction(Opcode.STOREM, paramDt, fpReg1 = argFpReg, labelSymbol = symbol)
+                        } else {
+                            val argReg = codeGen.vmRegisters.nextFree()
+                            code += translateExpression(arg, argReg, -1)
+                            code += IRCodeInstruction(Opcode.STOREM, paramDt, reg1 = argReg, labelSymbol = symbol)
+                        }
+                    }
+                }
+                code += IRCodeInstruction(Opcode.CALL, labelSymbol=fcall.functionName.joinToString("."))
+                if(fcall.type==DataType.FLOAT) {
+                    if (!fcall.void && resultFpRegister != 0) {
+                        // Call convention: result value is in fr0, so put it in the required register instead.
+                        code += IRCodeInstruction(Opcode.LOADR, VmDataType.FLOAT, fpReg1 = resultFpRegister, fpReg2 = 0)
+                    }
+                } else {
+                    if (!fcall.void && resultRegister != 0) {
+                        // Call convention: result value is in r0, so put it in the required register instead.
+                        code += IRCodeInstruction(Opcode.LOADR, codeGen.vmType(fcall.type), reg1 = resultRegister, reg2 = 0)
+                    }
+                }
+                return code
+            }
+            is StRomSub -> {
+                val code = IRCodeChunk(fcall.position)
+                for ((arg, parameter) in fcall.args.zip(callTarget.parameters)) {
+                    val paramDt = codeGen.vmType(parameter.type)
+                    val paramRegStr = if(parameter.register.registerOrPair!=null) parameter.register.registerOrPair.toString() else parameter.register.statusflag.toString()
+                    if(codeGen.isZero(arg)) {
+                        code += IRCodeInstruction(Opcode.STOREZCPU, paramDt, labelSymbol = paramRegStr)
+                    } else {
+                        if (paramDt == VmDataType.FLOAT)
+                            throw AssemblyError("doesn't support float register argument in asm romsub")
+                        val argReg = codeGen.vmRegisters.nextFree()
+                        code += translateExpression(arg, argReg, -1)
+                        code += IRCodeInstruction(Opcode.STORECPU, paramDt, reg1 = argReg, labelSymbol = paramRegStr)
+                    }
+                }
+                code += IRCodeInstruction(Opcode.CALL, value=callTarget.address.toInt())
+                if(!fcall.void) {
+                    if(callTarget.returns.size!=1)
+                        throw AssemblyError("expect precisely 1 return value")
+                    if(fcall.type==DataType.FLOAT)
+                        throw AssemblyError("doesn't support float register result in asm romsub")
+                    val returns = callTarget.returns.single()
+                    val regStr = if(returns.registerOrPair!=null) returns.registerOrPair.toString() else returns.statusflag.toString()
+                    code += IRCodeInstruction(Opcode.LOADCPU, codeGen.vmType(fcall.type), reg1=resultRegister, labelSymbol = regStr)
+                }
+                return code
+            }
+            else -> throw AssemblyError("invalid node type")
+        }
+    }
+
+}

codeGenIntermediate/src/prog8/codegen/intermediate/IRPeepholeOptimizer.kt

@@ -0,0 +1,180 @@
+package prog8.codegen.intermediate
+
+import prog8.intermediate.*
+
+internal class IRPeepholeOptimizer(private val irprog: IRProgram) {
+    fun optimize() {
+        irprog.blocks.asSequence().flatMap { it.subroutines }.forEach { sub ->
+            sub.chunks.forEach { chunk ->
+                // we don't optimize Inline Asm chunks here.
+                if(chunk is IRCodeChunk) {
+                    do {
+                        val indexedInstructions = chunk.lines.withIndex()
+                            .filter { it.value is IRCodeInstruction }
+                            .map { IndexedValue(it.index, (it.value as IRCodeInstruction).ins) }
+                        val changed = removeNops(chunk, indexedInstructions)
+                                || removeDoubleLoadsAndStores(chunk, indexedInstructions)       // TODO not yet implemented
+                                || removeUselessArithmetic(chunk, indexedInstructions)
+                                || removeWeirdBranches(chunk, indexedInstructions)
+                                || removeDoubleSecClc(chunk, indexedInstructions)
+                                || cleanupPushPop(chunk, indexedInstructions)
+                        // TODO other optimizations:
+                        //  more complex optimizations such as unused registers
+                    } while (changed)
+                }
+            }
+        }
+    }
+
+    private fun cleanupPushPop(chunk: IRCodeChunk, indexedInstructions: List<IndexedValue<Instruction>>): Boolean {
+        //  push followed by pop to same target, or different target->replace with load
+        var changed = false
+        indexedInstructions.reversed().forEach { (idx, ins) ->
+            if(ins.opcode== Opcode.PUSH) {
+                if(idx < chunk.lines.size-1) {
+                    val insAfter = chunk.lines[idx+1] as? IRCodeInstruction
+                    if(insAfter!=null && insAfter.ins.opcode == Opcode.POP) {
+                        if(ins.reg1==insAfter.ins.reg1) {
+                            chunk.lines.removeAt(idx)
+                            chunk.lines.removeAt(idx)
+                        } else {
+                            chunk.lines[idx] = IRCodeInstruction(Opcode.LOADR, ins.type, reg1=insAfter.ins.reg1, reg2=ins.reg1)
+                            chunk.lines.removeAt(idx+1)
+                        }
+                        changed = true
+                    }
+                }
+            }
+        }
+        return changed
+    }
+
+    private fun removeDoubleSecClc(chunk: IRCodeChunk, indexedInstructions: List<IndexedValue<Instruction>>): Boolean {
+        //  double sec, clc
+        //  sec+clc or clc+sec
+        var changed = false
+        indexedInstructions.reversed().forEach { (idx, ins) ->
+            if(ins.opcode== Opcode.SEC || ins.opcode== Opcode.CLC) {
+                if(idx < chunk.lines.size-1) {
+                    val insAfter = chunk.lines[idx+1] as? IRCodeInstruction
+                    if(insAfter?.ins?.opcode == ins.opcode) {
+                        chunk.lines.removeAt(idx)
+                        changed = true
+                    }
+                    else if(ins.opcode== Opcode.SEC && insAfter?.ins?.opcode== Opcode.CLC) {
+                        chunk.lines.removeAt(idx)
+                        changed = true
+                    }
+                    else if(ins.opcode== Opcode.CLC && insAfter?.ins?.opcode== Opcode.SEC) {
+                        chunk.lines.removeAt(idx)
+                        changed = true
+                    }
+                }
+            }
+        }
+        return changed
+    }
+
+    private fun removeWeirdBranches(chunk: IRCodeChunk, indexedInstructions: List<IndexedValue<Instruction>>): Boolean {
+        //  jump/branch to label immediately below
+        var changed = false
+        indexedInstructions.reversed().forEach { (idx, ins) ->
+            val labelSymbol = ins.labelSymbol
+            if(ins.opcode== Opcode.JUMP && labelSymbol!=null) {
+                // if jumping to label immediately following this
+                if(idx < chunk.lines.size-1) {
+                    val label = chunk.lines[idx+1] as? IRCodeLabel
+                    if(labelSymbol.size==1 && label?.name == labelSymbol[0]) {
+                        chunk.lines.removeAt(idx)
+                        changed = true
+                    }
+                }
+            }
+        }
+        return changed
+    }
+
+    private fun removeUselessArithmetic(chunk: IRCodeChunk, indexedInstructions: List<IndexedValue<Instruction>>): Boolean {
+        // note: this is hard to solve for the non-immediate instructions atm because the values are loaded into registers first
+        var changed = false
+        indexedInstructions.reversed().forEach { (idx, ins) ->
+            when (ins.opcode) {
+                Opcode.DIV, Opcode.DIVS, Opcode.MUL, Opcode.MOD -> {
+                    if (ins.value == 1) {
+                        chunk.lines.removeAt(idx)
+                        changed = true
+                    }
+                }
+                Opcode.ADD, Opcode.SUB -> {
+                    if (ins.value == 1) {
+                        chunk.lines[idx] = IRCodeInstruction(
+                            if (ins.opcode == Opcode.ADD) Opcode.INC else Opcode.DEC,
+                            ins.type,
+                            ins.reg1
+                        )
+                        changed = true
+                    } else if (ins.value == 0) {
+                        chunk.lines.removeAt(idx)
+                        changed = true
+                    }
+                }
+                Opcode.AND -> {
+                    if (ins.value == 0) {
+                        chunk.lines[idx] = IRCodeInstruction(Opcode.LOAD, ins.type, reg1 = ins.reg1, value = 0)
+                        changed = true
+                    } else if (ins.value == 255 && ins.type == VmDataType.BYTE) {
+                        chunk.lines.removeAt(idx)
+                        changed = true
+                    } else if (ins.value == 65535 && ins.type == VmDataType.WORD) {
+                        chunk.lines.removeAt(idx)
+                        changed = true
+                    }
+                }
+                Opcode.OR -> {
+                    if (ins.value == 0) {
+                        chunk.lines.removeAt(idx)
+                        changed = true
+                    } else if ((ins.value == 255 && ins.type == VmDataType.BYTE) || (ins.value == 65535 && ins.type == VmDataType.WORD)) {
+                        chunk.lines[idx] = IRCodeInstruction(Opcode.LOAD, ins.type, reg1 = ins.reg1, value = ins.value)
+                        changed = true
+                    }
+                }
+                Opcode.XOR -> {
+                    if (ins.value == 0) {
+                        chunk.lines.removeAt(idx)
+                        changed = true
+                    }
+                }
+                else -> {}
+            }
+        }
+        return changed
+    }
+
+    private fun removeNops(chunk: IRCodeChunk, indexedInstructions: List<IndexedValue<Instruction>>): Boolean {
+        var changed = false
+        indexedInstructions.reversed().forEach { (idx, ins) ->
+            if (ins.opcode == Opcode.NOP) {
+                changed = true
+                chunk.lines.removeAt(idx)
+            }
+        }
+        return changed
+    }
+
+    private fun removeDoubleLoadsAndStores(chunk: IRCodeChunk, indexedInstructions: List<IndexedValue<Instruction>>): Boolean {
+        var changed = false
+        indexedInstructions.forEach { (idx, ins) ->
+
+            // TODO: detect multiple loads to the same target registers, only keep first (if source is not I/O memory)
+            // TODO: detect multiple stores to the same target, only keep first (if target is not I/O memory)
+            // TODO: detect multiple float ffrom/fto to the same target, only keep first
+            // TODO: detect multiple sequential rnd with same reg1, only keep one
+            // TODO: detect subsequent same xors/nots/negs, remove the pairs completely as they cancel out
+            // TODO: detect multiple same ands, ors; only keep first
+            // TODO: (hard) detect multiple registers being assigned the same value (and not changed) - use only 1 of them
+            // ...
+        }
+        return changed
+    }
+}

codeGenIntermediate/src/prog8/codegen/intermediate/RegisterPool.kt

@@ -0,0 +1,27 @@
+package prog8.codegen.intermediate
+
+import prog8.code.core.AssemblyError
+
+internal class RegisterPool {
+    private var firstFree: Int=3        // integer registers 0,1,2 are reserved
+    private var firstFreeFloat: Int=0
+
+    fun peekNext() = firstFree
+    fun peekNextFloat() = firstFreeFloat
+
+    fun nextFree(): Int {
+        val result = firstFree
+        firstFree++
+        if(firstFree>65535)
+            throw AssemblyError("out of virtual registers (int)")
+        return result
+    }
+
+    fun nextFreeFloat(): Int {
+        val result = firstFreeFloat
+        firstFreeFloat++
+        if(firstFreeFloat>65535)
+            throw AssemblyError("out of virtual registers (fp)")
+        return result
+    }
+}

codeGenIntermediate/test/Dummies.kt

@@ -0,0 +1,20 @@
+import prog8.code.core.DataType
+import prog8.code.core.Encoding
+import prog8.code.core.IMemSizer
+import prog8.code.core.IStringEncoding
+
+
+internal object DummyMemsizer : IMemSizer {
+    override fun memorySize(dt: DataType) = 0
+    override fun memorySize(arrayDt: DataType, numElements: Int) = 0
+}
+
+internal object DummyStringEncoder : IStringEncoding {
+    override fun encodeString(str: String, encoding: Encoding): List<UByte> {
+        return emptyList()
+    }
+
+    override fun decodeString(bytes: List<UByte>, encoding: Encoding): String {
+        return ""
+    }
+}