diskio.f_open_w() error handling back to what it was before

Otherwise it eats the status message. Added comment that you have to check this manually to be sure if the call succeeded or not!
removed cx16.FB_cursor_position2() because it was only for use in the graphics module
2026-10-22 20:02:27 +00:00 · 2023-11-12 21:14:06 +01:00 · 2023-11-12 16:40:13 +01:00 · 2023-11-12 05:28:24 +01:00 · 2023-11-11 14:31:48 +01:00 · 2023-11-11 14:26:40 +01:00
577 changed files with 98927 additions and 33840 deletions
@@ -0,0 +1,36 @@
+name: Build and Test the Prog8 compiler
+
+on:
+  push:
+  workflow_dispatch:
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v3
+
+      - name: build and install recent 64tass
+        run: |
+          sudo apt-get install -y make build-essential
+          git clone --depth=1 https://github.com/irmen/64tass
+          cd 64tass
+          make -j4
+          sudo make install
+
+      - name: Set up JDK 11
+        uses: actions/setup-java@v3
+        with:
+          java-version: 11
+          distribution: adopt
+
+      - name: Build and test with Gradle
+        run: ./gradlew build shadowJar --no-daemon
+
+      - name: Create compiler shadowJar artifact
+        uses: actions/upload-artifact@v3
+        with:
+          name: prog8-compiler-jar-zipped
+          path: compiler/build/libs/*-all.jar
@@ -1,20 +1,21 @@
-**/.idea/
-/build/
-/dist/
-/output/
+.idea/workspace.xml
+.idea/discord.xml
+build/
+dist/
+output/
 .*cache/
 *.directory
 *.prg
-*.asm
 *.bin
 *.labels.txt
 *.vm.txt
 *.vice-mon-list
 docs/build
 out/
-**/*.interp
-**/*.tokens
-
+parser/**/*.interp
+parser/**/*.tokens
+parser/**/*.java
+compiler/src/prog8/buildversion/*
 *.py[cod]
 *.egg
 *.egg-info
@@ -25,10 +26,12 @@ __pycache__/
 parser.out
 parsetab.py
 .pytest_cache/
-compiler/src/prog8_kotlin.jar
-compiler/src/compiled_java
 .attach_pid*
+compiler/lib/

 .gradle
-build/
+**/BuildVersion.kt
 /prog8compiler.jar
+sd*.img
+*.d64
+
@@ -0,0 +1,2 @@
+# Default ignored files
+/shelf/
@@ -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>
@@ -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>
@@ -0,0 +1,5 @@
+<component name="ProjectCodeStyleConfiguration">
+  <state>
+    <option name="USE_PER_PROJECT_SETTINGS" value="true" />
+  </state>
+</component>
@@ -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>
@@ -0,0 +1,3 @@
+<component name="ProjectDictionaryState">
+  <dictionary name="irmen" />
+</component>
@@ -0,0 +1,18 @@
+<component name="InspectionProjectProfileManager">
+  <profile version="1.0">
+    <option name="myName" value="Project Default" />
+    <inspection_tool class="DuplicatedCode" enabled="true" level="WEAK WARNING" enabled_by_default="true">
+      <Languages>
+        <language minSize="70" name="Kotlin" />
+        <language isEnabled="false" name="Groovy" />
+      </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" />
+      <option name="processComments" value="false" />
+    </inspection_tool>
+  </profile>
+</component>
@@ -0,0 +1,9 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="Kotlin2JvmCompilerArguments">
+    <option name="jvmTarget" value="11" />
+  </component>
+  <component name="KotlinJpsPluginSettings">
+    <option name="version" value="1.9.20" />
+  </component>
+</project>
@@ -0,0 +1,19 @@
+<component name="libraryTable">
+  <library name="KotlinJavaRuntime">
+    <CLASSES>
+      <root url="jar://$KOTLIN_BUNDLED$/lib/kotlin-stdlib.jar!/" />
+      <root url="jar://$KOTLIN_BUNDLED$/lib/kotlin-reflect.jar!/" />
+      <root url="jar://$KOTLIN_BUNDLED$/lib/kotlin-test.jar!/" />
+      <root url="jar://$KOTLIN_BUNDLED$/lib/kotlin-stdlib-jdk7.jar!/" />
+      <root url="jar://$KOTLIN_BUNDLED$/lib/kotlin-stdlib-jdk8.jar!/" />
+    </CLASSES>
+    <JAVADOC />
+    <SOURCES>
+      <root url="jar://$KOTLIN_BUNDLED$/lib/kotlin-stdlib-sources.jar!/" />
+      <root url="jar://$KOTLIN_BUNDLED$/lib/kotlin-reflect-sources.jar!/" />
+      <root url="jar://$KOTLIN_BUNDLED$/lib/kotlin-test-sources.jar!/" />
+      <root url="jar://$KOTLIN_BUNDLED$/lib/kotlin-stdlib-jdk7-sources.jar!/" />
+      <root url="jar://$KOTLIN_BUNDLED$/lib/kotlin-stdlib-jdk8-sources.jar!/" />
+    </SOURCES>
+  </library>
+</component>
@@ -0,0 +1,18 @@
+<component name="libraryTable">
+  <library name="antlr.antlr4" type="repository">
+    <properties maven-id="org.antlr:antlr4:4.13.1">
+      <exclude>
+        <dependency maven-id="com.ibm.icu:icu4j" />
+      </exclude>
+    </properties>
+    <CLASSES>
+      <root url="jar://$MAVEN_REPOSITORY$/org/antlr/antlr4/4.13.1/antlr4-4.13.1.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/antlr/antlr4-runtime/4.13.1/antlr4-runtime-4.13.1.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/ST4/4.3.4/ST4-4.3.4.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/abego/treelayout/org.abego.treelayout.core/1.0.3/org.abego.treelayout.core-1.0.3.jar!/" />
+    </CLASSES>
+    <JAVADOC />
+    <SOURCES />
+  </library>
+</component>
@@ -0,0 +1,25 @@
+<component name="libraryTable">
+  <library name="github.hypfvieh.dbus.java" type="repository">
+    <properties maven-id="com.github.hypfvieh:dbus-java:3.3.2" />
+    <CLASSES>
+      <root url="jar://$MAVEN_REPOSITORY$/com/github/hypfvieh/dbus-java/3.3.2/dbus-java-3.3.2.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/com/github/jnr/jnr-unixsocket/0.38.17/jnr-unixsocket-0.38.17.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/com/github/jnr/jnr-ffi/2.2.11/jnr-ffi-2.2.11.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/com/github/jnr/jffi/1.3.9/jffi-1.3.9.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/com/github/jnr/jffi/1.3.9/jffi-1.3.9-native.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/ow2/asm/asm/9.2/asm-9.2.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/ow2/asm/asm-commons/9.2/asm-commons-9.2.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/ow2/asm/asm-analysis/9.2/asm-analysis-9.2.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/ow2/asm/asm-tree/9.2/asm-tree-9.2.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/ow2/asm/asm-util/9.2/asm-util-9.2.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/0.10.3/jnr-constants-0.10.3.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/com/github/jnr/jnr-enxio/0.32.13/jnr-enxio-0.32.13.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/com/github/jnr/jnr-posix/3.1.15/jnr-posix-3.1.15.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/slf4j/slf4j-api/1.7.36/slf4j-api-1.7.36.jar!/" />
+    </CLASSES>
+    <JAVADOC />
+    <SOURCES />
+  </library>
+</component>
@@ -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>
@@ -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:5.7.2" />
+    <CLASSES>
+      <root url="jar://$MAVEN_REPOSITORY$/io/kotest/kotest-assertions-core-jvm/5.7.2/kotest-assertions-core-jvm-5.7.2.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/kotlin/kotlin-stdlib-jdk8/1.8.10/kotlin-stdlib-jdk8-1.8.10.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/kotlin/kotlin-stdlib/1.8.10/kotlin-stdlib-1.8.10.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/kotlin/kotlin-stdlib-jdk7/1.8.10/kotlin-stdlib-jdk7-1.8.10.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/io/kotest/kotest-assertions-shared-jvm/5.7.2/kotest-assertions-shared-jvm-5.7.2.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/io/github/java-diff-utils/java-diff-utils/4.12/java-diff-utils-4.12.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/opentest4j/opentest4j/1.3.0/opentest4j-1.3.0.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/kotlin/kotlin-stdlib-common/1.8.10/kotlin-stdlib-common-1.8.10.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/kotlinx/kotlinx-coroutines-jdk8/1.7.0/kotlinx-coroutines-jdk8-1.7.0.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/kotlin/kotlin-reflect/1.8.10/kotlin-reflect-1.8.10.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/io/kotest/kotest-common-jvm/5.7.2/kotest-common-jvm-5.7.2.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/io/kotest/kotest-assertions-api-jvm/5.7.2/kotest-assertions-api-jvm-5.7.2.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/kotlinx/kotlinx-coroutines-core-jvm/1.7.0/kotlinx-coroutines-core-jvm-1.7.0.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/annotations/23.0.0/annotations-23.0.0.jar!/" />
+    </CLASSES>
+    <JAVADOC />
+    <SOURCES />
+  </library>
+</component>
@@ -0,0 +1,44 @@
+<component name="libraryTable">
+  <library name="io.kotest.runner.junit5.jvm" type="repository">
+    <properties maven-id="io.kotest:kotest-runner-junit5-jvm:5.7.2" />
+    <CLASSES>
+      <root url="jar://$MAVEN_REPOSITORY$/io/kotest/kotest-runner-junit5-jvm/5.7.2/kotest-runner-junit5-jvm-5.7.2.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/io/kotest/kotest-framework-api-jvm/5.7.2/kotest-framework-api-jvm-5.7.2.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/io/kotest/kotest-assertions-shared-jvm/5.7.2/kotest-assertions-shared-jvm-5.7.2.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/io/github/java-diff-utils/java-diff-utils/4.12/java-diff-utils-4.12.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/kotlinx/kotlinx-coroutines-test-jvm/1.7.0/kotlinx-coroutines-test-jvm-1.7.0.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/io/kotest/kotest-common-jvm/5.7.2/kotest-common-jvm-5.7.2.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/io/kotest/kotest-framework-engine-jvm/5.7.2/kotest-framework-engine-jvm-5.7.2.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/io/github/classgraph/classgraph/4.8.162/classgraph-4.8.162.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/com/github/ajalt/mordant/1.2.1/mordant-1.2.1.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/com/github/ajalt/colormath/1.2.0/colormath-1.2.0.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/opentest4j/opentest4j/1.3.0/opentest4j-1.3.0.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/kotlinx/kotlinx-coroutines-debug/1.7.0/kotlinx-coroutines-debug-1.7.0.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/net/java/dev/jna/jna/5.9.0/jna-5.9.0.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/net/java/dev/jna/jna-platform/5.9.0/jna-platform-5.9.0.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/net/bytebuddy/byte-buddy/1.10.9/byte-buddy-1.10.9.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/net/bytebuddy/byte-buddy-agent/1.10.9/byte-buddy-agent-1.10.9.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/io/kotest/kotest-framework-discovery-jvm/5.7.2/kotest-framework-discovery-jvm-5.7.2.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/io/kotest/kotest-assertions-core-jvm/5.7.2/kotest-assertions-core-jvm-5.7.2.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/kotlinx/kotlinx-coroutines-jdk8/1.7.0/kotlinx-coroutines-jdk8-1.7.0.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/io/kotest/kotest-assertions-api-jvm/5.7.2/kotest-assertions-api-jvm-5.7.2.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/io/kotest/kotest-extensions-jvm/5.7.2/kotest-extensions-jvm-5.7.2.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/io/kotest/kotest-framework-concurrency-jvm/5.7.2/kotest-framework-concurrency-jvm-5.7.2.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/kotlinx/kotlinx-coroutines-core-jvm/1.7.0/kotlinx-coroutines-core-jvm-1.7.0.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/annotations/23.0.0/annotations-23.0.0.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/junit/platform/junit-platform-engine/1.8.2/junit-platform-engine-1.8.2.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/junit/platform/junit-platform-commons/1.8.2/junit-platform-commons-1.8.2.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/apiguardian/apiguardian-api/1.1.2/apiguardian-api-1.1.2.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/junit/platform/junit-platform-suite-api/1.8.2/junit-platform-suite-api-1.8.2.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/junit/platform/junit-platform-launcher/1.8.2/junit-platform-launcher-1.8.2.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/junit/jupiter/junit-jupiter-api/5.8.2/junit-jupiter-api-5.8.2.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/kotlin/kotlin-stdlib-jdk8/1.8.10/kotlin-stdlib-jdk8-1.8.10.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/kotlin/kotlin-stdlib/1.8.10/kotlin-stdlib-1.8.10.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/kotlin/kotlin-stdlib-jdk7/1.8.10/kotlin-stdlib-jdk7-1.8.10.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/kotlin/kotlin-stdlib-common/1.8.10/kotlin-stdlib-common-1.8.10.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/kotlin/kotlin-reflect/1.8.10/kotlin-reflect-1.8.10.jar!/" />
+    </CLASSES>
+    <JAVADOC />
+    <SOURCES />
+  </library>
+</component>
@@ -0,0 +1,10 @@
+<component name="libraryTable">
+  <library name="jetbrains.kotlinx.cli.jvm" type="repository">
+    <properties include-transitive-deps="false" maven-id="org.jetbrains.kotlinx:kotlinx-cli-jvm:0.3.6" />
+    <CLASSES>
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/kotlinx/kotlinx-cli-jvm/0.3.6/kotlinx-cli-jvm-0.3.6.jar!/" />
+    </CLASSES>
+    <JAVADOC />
+    <SOURCES />
+  </library>
+</component>
@@ -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:1.1.18" />
+    <CLASSES>
+      <root url="jar://$MAVEN_REPOSITORY$/com/michael-bull/kotlin-result/kotlin-result-jvm/1.1.18/kotlin-result-jvm-1.1.18.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/kotlin/kotlin-stdlib-jdk8/1.8.10/kotlin-stdlib-jdk8-1.8.10.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/kotlin/kotlin-stdlib/1.8.10/kotlin-stdlib-1.8.10.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-jdk7/1.8.10/kotlin-stdlib-jdk7-1.8.10.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/kotlin/kotlin-stdlib-common/1.8.10/kotlin-stdlib-common-1.8.10.jar!/" />
+    </CLASSES>
+    <JAVADOC />
+    <SOURCES />
+  </library>
+</component>
@@ -0,0 +1,11 @@
+<component name="libraryTable">
+  <library name="slf4j.simple" type="repository">
+    <properties maven-id="org.slf4j:slf4j-simple:2.0.9" />
+    <CLASSES>
+      <root url="jar://$MAVEN_REPOSITORY$/org/slf4j/slf4j-simple/2.0.9/slf4j-simple-2.0.9.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/slf4j/slf4j-api/2.0.9/slf4j-api-2.0.9.jar!/" />
+    </CLASSES>
+    <JAVADOC />
+    <SOURCES />
+  </library>
+</component>
@@ -0,0 +1,18 @@
+<component name="libraryTable">
+  <library name="takes" type="repository">
+    <properties maven-id="org.takes:takes:1.24.4" />
+    <CLASSES>
+      <root url="jar://$MAVEN_REPOSITORY$/org/takes/takes/1.24.4/takes-1.24.4.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/cactoos/cactoos/0.54.0/cactoos-0.54.0.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/javax/xml/bind/jaxb-api/2.4.0-b180830.0359/jaxb-api-2.4.0-b180830.0359.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/javax/activation/javax.activation-api/1.2.0/javax.activation-api-1.2.0.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/com/sun/xml/bind/jaxb-core/4.0.0/jaxb-core-4.0.0.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/jakarta/xml/bind/jakarta.xml.bind-api/4.0.0/jakarta.xml.bind-api-4.0.0.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/jakarta/activation/jakarta.activation-api/2.1.0/jakarta.activation-api-2.1.0.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/eclipse/angus/angus-activation/1.0.0/angus-activation-1.0.0.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/com/sun/xml/bind/jaxb-impl/4.0.0/jaxb-impl-4.0.0.jar!/" />
+    </CLASSES>
+    <JAVADOC />
+    <SOURCES />
+  </library>
+</component>
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="MarkdownEnhProjectSettings">
+    <AnnotatorSettings targetHasSpaces="true" linkCaseMismatch="true" wikiCaseMismatch="true" wikiLinkHasDashes="true" notUnderWikiHome="true" targetNotWikiPageExt="true" notUnderSourceWikiHome="true" targetNameHasAnchor="true" targetPathHasAnchor="true" wikiLinkHasSlash="true" wikiLinkHasSubdir="true" wikiLinkHasOnlyAnchor="true" linkTargetsWikiHasExt="true" linkTargetsWikiHasBadExt="true" notUnderSameRepo="true" targetNotUnderVcs="false" linkNeedsExt="true" linkHasBadExt="true" linkTargetNeedsExt="true" linkTargetHasBadExt="true" wikiLinkNotInWiki="true" imageTargetNotInRaw="true" repoRelativeAcrossVcsRoots="true" multipleWikiTargetsMatch="true" unresolvedLinkReference="true" linkIsIgnored="true" anchorIsIgnored="true" anchorIsUnresolved="true" anchorLineReferenceIsUnresolved="true" anchorLineReferenceFormat="true" anchorHasDuplicates="true" abbreviationDuplicates="true" abbreviationNotUsed="true" attributeIdDuplicateDefinition="true" attributeIdNotUsed="true" footnoteDuplicateDefinition="true" footnoteUnresolved="true" footnoteDuplicates="true" footnoteNotUsed="true" macroDuplicateDefinition="true" macroUnresolved="true" macroDuplicates="true" macroNotUsed="true" referenceDuplicateDefinition="true" referenceUnresolved="true" referenceDuplicates="true" referenceNotUsed="true" referenceUnresolvedNumericId="true" enumRefDuplicateDefinition="true" enumRefUnresolved="true" enumRefDuplicates="true" enumRefNotUsed="true" enumRefLinkUnresolved="true" enumRefLinkDuplicates="true" simTocUpdateNeeded="true" simTocTitleSpaceNeeded="true" />
+    <HtmlExportSettings updateOnSave="false" parentDir="" targetDir="" cssDir="css" scriptDir="js" plainHtml="false" imageDir="" copyLinkedImages="false" imagePathType="0" targetPathType="2" targetExt="" useTargetExt="false" noCssNoScripts="false" useElementStyleAttribute="false" linkToExportedHtml="true" exportOnSettingsChange="true" regenerateOnProjectOpen="false" linkFormatType="HTTP_ABSOLUTE" />
+    <LinkMapSettings>
+      <textMaps />
+    </LinkMapSettings>
+  </component>
+  <component name="MarkdownNavigatorHistory">
+    <PasteImageHistory checkeredTransparentBackground="false" filename="image" directory="" onPasteImageTargetRef="3" onPasteLinkText="0" onPasteImageElement="1" onPasteLinkElement="1" onPasteReferenceElement="2" cornerRadius="20" borderColor="0" transparentColor="16777215" borderWidth="1" trimTop="0" trimBottom="0" trimLeft="0" trimRight="0" transparent="false" roundCorners="false" showPreview="true" bordered="false" scaled="false" cropped="false" hideInapplicableOperations="false" preserveLinkFormat="false" scale="50" scalingInterpolation="1" transparentTolerance="0" saveAsDefaultOnOK="false" linkFormat="0" addHighlights="false" showHighlightCoordinates="true" showHighlights="false" mouseSelectionAddsHighlight="false" outerFilled="false" outerFillColor="0" outerFillTransparent="true" outerFillAlpha="30">
+      <highlightList />
+      <directories />
+      <filenames />
+    </PasteImageHistory>
+    <CopyImageHistory checkeredTransparentBackground="false" filename="image" directory="" onPasteImageTargetRef="3" onPasteLinkText="0" onPasteImageElement="1" onPasteLinkElement="1" onPasteReferenceElement="2" cornerRadius="20" borderColor="0" transparentColor="16777215" borderWidth="1" trimTop="0" trimBottom="0" trimLeft="0" trimRight="0" transparent="false" roundCorners="false" showPreview="true" bordered="false" scaled="false" cropped="false" hideInapplicableOperations="false" preserveLinkFormat="false" scale="50" scalingInterpolation="1" transparentTolerance="0" saveAsDefaultOnOK="false" linkFormat="0" addHighlights="false" showHighlightCoordinates="true" showHighlights="false" mouseSelectionAddsHighlight="false" outerFilled="false" outerFillColor="0" outerFillTransparent="true" outerFillAlpha="30">
+      <highlightList />
+      <directories />
+      <filenames />
+    </CopyImageHistory>
+    <PasteLinkHistory onPasteImageTargetRef="3" onPasteTargetRef="1" onPasteLinkText="0" onPasteImageElement="1" onPasteLinkElement="1" onPasteWikiElement="2" onPasteReferenceElement="2" hideInapplicableOperations="false" preserveLinkFormat="false" useHeadingForLinkText="false" linkFormat="0" saveAsDefaultOnOK="false" />
+    <TableToJsonHistory>
+      <entries />
+    </TableToJsonHistory>
+    <TableSortHistory>
+      <entries />
+    </TableSortHistory>
+  </component>
+</project>
@@ -0,0 +1,57 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="FlexmarkProjectSettings">
+    <FlexmarkHtmlSettings flexmarkSpecExampleRendering="0" flexmarkSpecExampleRenderHtml="false">
+      <flexmarkSectionLanguages>
+        <option name="1" value="Markdown" />
+        <option name="2" value="HTML" />
+        <option name="3" value="flexmark-ast:1" />
+      </flexmarkSectionLanguages>
+    </FlexmarkHtmlSettings>
+  </component>
+  <component name="MarkdownProjectSettings">
+    <PreviewSettings splitEditorLayout="SPLIT" splitEditorPreview="PREVIEW" useGrayscaleRendering="false" zoomFactor="1.0" maxImageWidth="0" synchronizePreviewPosition="true" highlightPreviewType="LINE" highlightFadeOut="5" highlightOnTyping="true" synchronizeSourcePosition="true" verticallyAlignSourceAndPreviewSyncPosition="true" showSearchHighlightsInPreview="true" showSelectionInPreview="true" lastLayoutSetsDefault="false">
+      <PanelProvider>
+        <provider providerId="com.vladsch.md.nav.editor.javafx.html.panel" providerName="JavaFX WebView" />
+      </PanelProvider>
+    </PreviewSettings>
+    <ParserSettings gitHubSyntaxChange="false" correctedInvalidSettings="false" emojiShortcuts="1" emojiImages="0">
+      <PegdownExtensions>
+        <option name="ANCHORLINKS" value="true" />
+        <option name="ATXHEADERSPACE" value="true" />
+        <option name="FENCED_CODE_BLOCKS" value="true" />
+        <option name="INTELLIJ_DUMMY_IDENTIFIER" value="true" />
+        <option name="RELAXEDHRULES" value="true" />
+        <option name="STRIKETHROUGH" value="true" />
+        <option name="TABLES" value="true" />
+        <option name="TASKLISTITEMS" value="true" />
+      </PegdownExtensions>
+      <ParserOptions>
+        <option name="COMMONMARK_LISTS" value="true" />
+        <option name="EMOJI_SHORTCUTS" value="true" />
+        <option name="GFM_TABLE_RENDERING" value="true" />
+        <option name="PRODUCTION_SPEC_PARSER" value="true" />
+        <option name="SIM_TOC_BLANK_LINE_SPACER" value="true" />
+      </ParserOptions>
+    </ParserSettings>
+    <HtmlSettings headerTopEnabled="false" headerBottomEnabled="false" bodyTopEnabled="false" bodyBottomEnabled="false" addPageHeader="false" imageUriSerials="false" addDocTypeHtml="true" noParaTags="false" plantUmlConversion="0">
+      <GeneratorProvider>
+        <provider providerId="com.vladsch.md.nav.editor.javafx.html.generator" providerName="JavaFx HTML Generator" />
+      </GeneratorProvider>
+      <headerTop />
+      <headerBottom />
+      <bodyTop />
+      <bodyBottom />
+    </HtmlSettings>
+    <CssSettings previewScheme="UI_SCHEME" cssUri="" isCssUriEnabled="false" isCssUriSerial="true" isCssTextEnabled="false" isDynamicPageWidth="true">
+      <StylesheetProvider>
+        <provider providerId="com.vladsch.md.nav.editor.javafx.html.css" providerName="Default JavaFx Stylesheet" />
+      </StylesheetProvider>
+      <ScriptProviders>
+        <provider providerId="com.vladsch.md.nav.editor.hljs.html.script" providerName="HighlightJS Script" />
+      </ScriptProviders>
+      <cssText />
+      <cssUriHistory />
+    </CssSettings>
+  </component>
+</project>
@@ -0,0 +1,28 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="ANTLRGenerationPreferences">
+    <option name="perGrammarGenerationSettings">
+      <list>
+        <PerGrammarGenerationSettings>
+          <option name="fileName" value="$PROJECT_DIR$/parser/antlr/Prog8ANTLR.g4" />
+          <option name="autoGen" value="true" />
+          <option name="outputDir" value="$PROJECT_DIR$/parser/src/prog8/parser" />
+          <option name="libDir" value="" />
+          <option name="encoding" value="" />
+          <option name="pkg" value="" />
+          <option name="language" value="" />
+          <option name="generateListener" value="false" />
+        </PerGrammarGenerationSettings>
+      </list>
+    </option>
+  </component>
+  <component name="Black">
+    <option name="sdkName" value="Python 3.11" />
+  </component>
+  <component name="FrameworkDetectionExcludesConfiguration">
+    <type id="Python" />
+  </component>
+  <component name="ProjectRootManager" version="2" languageLevel="JDK_11" default="true" project-jdk-name="openjdk-11" project-jdk-type="JavaSDK">
+    <output url="file://$PROJECT_DIR$/out" />
+  </component>
+</project>
@@ -0,0 +1,22 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<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>
@@ -0,0 +1,124 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="Palette2">
+    <group name="Swing">
+      <item class="com.intellij.uiDesigner.HSpacer" tooltip-text="Horizontal Spacer" icon="/com/intellij/uiDesigner/icons/hspacer.png" removable="false" auto-create-binding="false" can-attach-label="false">
+        <default-constraints vsize-policy="1" hsize-policy="6" anchor="0" fill="1" />
+      </item>
+      <item class="com.intellij.uiDesigner.VSpacer" tooltip-text="Vertical Spacer" icon="/com/intellij/uiDesigner/icons/vspacer.png" removable="false" auto-create-binding="false" can-attach-label="false">
+        <default-constraints vsize-policy="6" hsize-policy="1" anchor="0" fill="2" />
+      </item>
+      <item class="javax.swing.JPanel" icon="/com/intellij/uiDesigner/icons/panel.png" removable="false" auto-create-binding="false" can-attach-label="false">
+        <default-constraints vsize-policy="3" hsize-policy="3" anchor="0" fill="3" />
+      </item>
+      <item class="javax.swing.JScrollPane" icon="/com/intellij/uiDesigner/icons/scrollPane.png" removable="false" auto-create-binding="false" can-attach-label="true">
+        <default-constraints vsize-policy="7" hsize-policy="7" anchor="0" fill="3" />
+      </item>
+      <item class="javax.swing.JButton" icon="/com/intellij/uiDesigner/icons/button.png" removable="false" auto-create-binding="true" can-attach-label="false">
+        <default-constraints vsize-policy="0" hsize-policy="3" anchor="0" fill="1" />
+        <initial-values>
+          <property name="text" value="Button" />
+        </initial-values>
+      </item>
+      <item class="javax.swing.JRadioButton" icon="/com/intellij/uiDesigner/icons/radioButton.png" removable="false" auto-create-binding="true" can-attach-label="false">
+        <default-constraints vsize-policy="0" hsize-policy="3" anchor="8" fill="0" />
+        <initial-values>
+          <property name="text" value="RadioButton" />
+        </initial-values>
+      </item>
+      <item class="javax.swing.JCheckBox" icon="/com/intellij/uiDesigner/icons/checkBox.png" removable="false" auto-create-binding="true" can-attach-label="false">
+        <default-constraints vsize-policy="0" hsize-policy="3" anchor="8" fill="0" />
+        <initial-values>
+          <property name="text" value="CheckBox" />
+        </initial-values>
+      </item>
+      <item class="javax.swing.JLabel" icon="/com/intellij/uiDesigner/icons/label.png" removable="false" auto-create-binding="false" can-attach-label="false">
+        <default-constraints vsize-policy="0" hsize-policy="0" anchor="8" fill="0" />
+        <initial-values>
+          <property name="text" value="Label" />
+        </initial-values>
+      </item>
+      <item class="javax.swing.JTextField" icon="/com/intellij/uiDesigner/icons/textField.png" removable="false" auto-create-binding="true" can-attach-label="true">
+        <default-constraints vsize-policy="0" hsize-policy="6" anchor="8" fill="1">
+          <preferred-size width="150" height="-1" />
+        </default-constraints>
+      </item>
+      <item class="javax.swing.JPasswordField" icon="/com/intellij/uiDesigner/icons/passwordField.png" removable="false" auto-create-binding="true" can-attach-label="true">
+        <default-constraints vsize-policy="0" hsize-policy="6" anchor="8" fill="1">
+          <preferred-size width="150" height="-1" />
+        </default-constraints>
+      </item>
+      <item class="javax.swing.JFormattedTextField" icon="/com/intellij/uiDesigner/icons/formattedTextField.png" removable="false" auto-create-binding="true" can-attach-label="true">
+        <default-constraints vsize-policy="0" hsize-policy="6" anchor="8" fill="1">
+          <preferred-size width="150" height="-1" />
+        </default-constraints>
+      </item>
+      <item class="javax.swing.JTextArea" icon="/com/intellij/uiDesigner/icons/textArea.png" removable="false" auto-create-binding="true" can-attach-label="true">
+        <default-constraints vsize-policy="6" hsize-policy="6" anchor="0" fill="3">
+          <preferred-size width="150" height="50" />
+        </default-constraints>
+      </item>
+      <item class="javax.swing.JTextPane" icon="/com/intellij/uiDesigner/icons/textPane.png" removable="false" auto-create-binding="true" can-attach-label="true">
+        <default-constraints vsize-policy="6" hsize-policy="6" anchor="0" fill="3">
+          <preferred-size width="150" height="50" />
+        </default-constraints>
+      </item>
+      <item class="javax.swing.JEditorPane" icon="/com/intellij/uiDesigner/icons/editorPane.png" removable="false" auto-create-binding="true" can-attach-label="true">
+        <default-constraints vsize-policy="6" hsize-policy="6" anchor="0" fill="3">
+          <preferred-size width="150" height="50" />
+        </default-constraints>
+      </item>
+      <item class="javax.swing.JComboBox" icon="/com/intellij/uiDesigner/icons/comboBox.png" removable="false" auto-create-binding="true" can-attach-label="true">
+        <default-constraints vsize-policy="0" hsize-policy="2" anchor="8" fill="1" />
+      </item>
+      <item class="javax.swing.JTable" icon="/com/intellij/uiDesigner/icons/table.png" removable="false" auto-create-binding="true" can-attach-label="false">
+        <default-constraints vsize-policy="6" hsize-policy="6" anchor="0" fill="3">
+          <preferred-size width="150" height="50" />
+        </default-constraints>
+      </item>
+      <item class="javax.swing.JList" icon="/com/intellij/uiDesigner/icons/list.png" removable="false" auto-create-binding="true" can-attach-label="false">
+        <default-constraints vsize-policy="6" hsize-policy="2" anchor="0" fill="3">
+          <preferred-size width="150" height="50" />
+        </default-constraints>
+      </item>
+      <item class="javax.swing.JTree" icon="/com/intellij/uiDesigner/icons/tree.png" removable="false" auto-create-binding="true" can-attach-label="false">
+        <default-constraints vsize-policy="6" hsize-policy="6" anchor="0" fill="3">
+          <preferred-size width="150" height="50" />
+        </default-constraints>
+      </item>
+      <item class="javax.swing.JTabbedPane" icon="/com/intellij/uiDesigner/icons/tabbedPane.png" removable="false" auto-create-binding="true" can-attach-label="false">
+        <default-constraints vsize-policy="3" hsize-policy="3" anchor="0" fill="3">
+          <preferred-size width="200" height="200" />
+        </default-constraints>
+      </item>
+      <item class="javax.swing.JSplitPane" icon="/com/intellij/uiDesigner/icons/splitPane.png" removable="false" auto-create-binding="false" can-attach-label="false">
+        <default-constraints vsize-policy="3" hsize-policy="3" anchor="0" fill="3">
+          <preferred-size width="200" height="200" />
+        </default-constraints>
+      </item>
+      <item class="javax.swing.JSpinner" icon="/com/intellij/uiDesigner/icons/spinner.png" removable="false" auto-create-binding="true" can-attach-label="true">
+        <default-constraints vsize-policy="0" hsize-policy="6" anchor="8" fill="1" />
+      </item>
+      <item class="javax.swing.JSlider" icon="/com/intellij/uiDesigner/icons/slider.png" removable="false" auto-create-binding="true" can-attach-label="false">
+        <default-constraints vsize-policy="0" hsize-policy="6" anchor="8" fill="1" />
+      </item>
+      <item class="javax.swing.JSeparator" icon="/com/intellij/uiDesigner/icons/separator.png" removable="false" auto-create-binding="false" can-attach-label="false">
+        <default-constraints vsize-policy="6" hsize-policy="6" anchor="0" fill="3" />
+      </item>
+      <item class="javax.swing.JProgressBar" icon="/com/intellij/uiDesigner/icons/progressbar.png" removable="false" auto-create-binding="true" can-attach-label="false">
+        <default-constraints vsize-policy="0" hsize-policy="6" anchor="0" fill="1" />
+      </item>
+      <item class="javax.swing.JToolBar" icon="/com/intellij/uiDesigner/icons/toolbar.png" removable="false" auto-create-binding="false" can-attach-label="false">
+        <default-constraints vsize-policy="0" hsize-policy="6" anchor="0" fill="1">
+          <preferred-size width="-1" height="20" />
+        </default-constraints>
+      </item>
+      <item class="javax.swing.JToolBar$Separator" icon="/com/intellij/uiDesigner/icons/toolbarSeparator.png" removable="false" auto-create-binding="false" can-attach-label="false">
+        <default-constraints vsize-policy="0" hsize-policy="0" anchor="0" fill="1" />
+      </item>
+      <item class="javax.swing.JScrollBar" icon="/com/intellij/uiDesigner/icons/scrollbar.png" removable="false" auto-create-binding="true" can-attach-label="false">
+        <default-constraints vsize-policy="6" hsize-policy="0" anchor="0" fill="2" />
+      </item>
+    </group>
+  </component>
+</project>
@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="VcsDirectoryMappings">
+    <mapping directory="$PROJECT_DIR$" vcs="Git" />
+  </component>
+</project>
@@ -0,0 +1,25 @@
+# .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-22.04
+  tools:
+    python: "3.11"
+
+# 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
@@ -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

@@ -1,105 +1,162 @@
-Prog8 - Structured Programming Language for 8-bit 6502/6510 microprocessors
-===========================================================================
+[![Documentation](https://readthedocs.org/projects/prog8/badge/?version=latest)](https://prog8.readthedocs.io/)
+
+Prog8 - Structured Programming Language for 8-bit 6502/65c02 microprocessors
+============================================================================

 *Written by Irmen de Jong (irmen@razorvine.net)*

-*Software license: GNU GPL 3.0, see file LICENSE*
-
-
-This is a structured programming language for the 8-bit 6502/6510 microprocessor from the late 1970's and 1980's
+This is a structured programming language for the 8-bit 6502/6510/65c02 microprocessor from the late 1970's and 1980's
 as used in many home computers from that era. It is a medium to low level programming language,
-which aims to provide many conveniences over raw assembly code (even when using a macro assembler):
+which aims to provide many conveniences over raw assembly code (even when using a macro assembler).

- reduction of source code length
- easier program understanding (because it's higher level, and more terse)
- option to automatically run the compiled program in the Vice emulator  
+Documentation
+-------------
+Full documentation (syntax reference, how to use the language and the compiler, etc.) can be found at:
+https://prog8.readthedocs.io/
+
+How to get it/build it
+----------------------
+
+- Download the latest [official release](https://github.com/irmen/prog8/releases) from github.
+- Or, if you want/need a bleeding edge development version, you can:
+  - download a build artifact zipfile from a recent [github action build](https://github.com/irmen/prog8/actions).
+  - you can also compile it yourself from source. [Instructions here](https://prog8.readthedocs.io/en/latest/compiling.html).
+
+Community
+---------
+Most of the development on Prog8 and the use of it is currently centered around 
+the [Commander X16](https://www.commanderx16.com/) retro computer. Their [discord server](https://discord.gg/nS2PqEC) contains a small channel
+dedicated to Prog8. Other than that, use the issue tracker on github.
+
+
+Software license
+----------------
+GNU GPL 3.0 (see file LICENSE), with exception for generated code:
+
+- 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
- subroutines have enforced input- and output parameter definitions
- various data types other than just bytes (16-bit words, floats, strings, 16-bit register pairs)
- automatic variable allocations, automatic string variables and string sharing
- constant folding in expressions (compile-time evaluation)
- automatic type conversions
- floating point operations
- abstracting away low level aspects such as ZeroPage handling, program startup, explicit memory addresses
+- various data types other than just bytes (16-bit words, floats, strings)
+- floating point math is supported if the target system provides floating point library routines (C64 and Cx16 both do)
+- 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.
+- 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
+- ``in`` expression for concise and efficient multi-value/containment check 
+- many built-in functions such as ``sin``, ``cos``, ``rnd``, ``abs``, ``min``, ``max``, ``sqrt``, ``msb``, ``rol``, ``ror``, ``swap``, ``sort`` and ``reverse``
+- various powerful built-in libraries to do I/O, number conversions, graphics and more  
+- 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
+- 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 nice editors and enjoy quick compilation times
+- can automatically run the program in the Vice emulator after succesful compilation
 - breakpoints, that let the Vice emulator drop into the monitor if execution hits them
 - source code labels automatically loaded in Vice emulator so it can show them in disassembly
- conditional gotos
- various code optimizations (code structure, logical and numerical expressions, ...) 
+
+*Multiple supported compiler targets* (contributions to improve these or to add support for other machines are welcome!):
+
+- "c64": Commodore-64  (6502 like CPU)
+- "c128": Commodore-128  (6502 like CPU - the Z80 cpu mode is not supported)
+- "cx16": [CommanderX16](https://www.commanderx16.com)  (65c02 CPU)
+- "pet32": Commodore PET (experimental)
+- "atari": Atari 8 bit such as 800XL (experimental)
+- 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)


-It is mainly targeted at the Commodore-64 machine at this time.

-Documentation is online at https://prog8.readthedocs.io/
-
-
-Required tools:
---------------
+Additional required tools
+-------------------------

 [64tass](https://sourceforge.net/projects/tass64/) - cross assembler. Install this on your shell path.
 A recent .exe version of this tool for Windows can be obtained from my [clone](https://github.com/irmen/64tass/releases) of this project.
 For other platforms it is very easy to compile it yourself (make ; make install).

-A **Java runtime (jre or jdk), version 8 or newer**  is required to run the packaged compiler.
-If you want to build it from source, you'll need a Kotlin 1.3 SDK as well (or for instance,
+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).

-It's handy to have a C-64 emulator or a real C-64 to run the programs on. The compiler assumes the presence
-of the [Vice emulator](http://vice-emu.sourceforge.net/)
+It's handy to have an emulator (or a real machine perhaps!) to run the programs on. The compiler assumes the presence
+of the [Vice emulator](http://vice-emu.sourceforge.net/)  for the C64 target,
+and a recent emulator version (R42 or newer) for the CommanderX16, such as [x16emu](https://cx16forum.com/forum/viewforum.php?f=30) 
+(preferred, this is the official emulator. If required, source code is [here](https://github.com/X16Community/x16-emulator/)).
+There is also [Box16](https://github.com/indigodarkwolf/box16) which has powerful debugging features.
+
+**Syntax highlighting:** for a few different editors, syntax highlighting definition files are provided.
+Look in the [syntax-files](https://github.com/irmen/prog8/tree/master/syntax-files) directory in the github repository to find them.


 Example code
 ------------

-When this code is compiled::
+This code calculates prime numbers using the Sieve of Eratosthenes algorithm::

-    %import c64lib
-    %import c64utils
-    %import c64flt
-
-    ~ main {
+    %import textio
+    %zeropage basicsafe
+    
+    main {
+    
+        ubyte[256] sieve
+        ubyte candidate_prime = 2       ; is increased in the loop
+    
        sub start() {
-            ; set text color and activate lowercase charset
-            c64.COLOR = 13
-            c64.VMCSB |= 2
-
-            ; use optimized routine to write text
-            c64scr.print("Hello!\n")
-
-            ; use iteration to write text
-            str question = "How are you?\n"
-            for ubyte char in question
-                c64.CHROUT(char)
-
-            ; use indexed loop to write characters
-            str bye = "Goodbye!\n"
-            for ubyte c in 0 to len(bye)
-                c64.CHROUT(bye[c])
-
-
-            float clock_seconds = ((mkword(c64.TIME_LO, c64.TIME_MID) as float)
-                                    + (c64.TIME_HI as float)*65536.0)
-                                     / 60
-            float hours = floor(clock_seconds / 3600)
-            clock_seconds -= hours*3600
-            float minutes = floor(clock_seconds / 60)
-            clock_seconds = floor(clock_seconds - minutes * 60.0)
-
-            c64scr.print("system time in ti$ is ")
-            c64flt.print_f(hours)
-            c64.CHROUT(':')
-            c64flt.print_f(minutes)
-            c64.CHROUT(':')
-            c64flt.print_f(clock_seconds)
-            c64.CHROUT('\n')
+            sys.memset(sieve, 256, false)   ; clear the sieve
+            txt.print("prime numbers up to 255:\n\n")
+            ubyte amount=0
+            repeat {
+                ubyte prime = find_next_prime()
+                if prime==0
+                    break
+                txt.print_ub(prime)
+                txt.print(", ")
+                amount++
+            }
+            txt.nl()
+            txt.print("number of primes (expected 54): ")
+            txt.print_ub(amount)
+            txt.nl()
+        }
+    
+        sub find_next_prime() -> ubyte {
+            while sieve[candidate_prime] {
+                candidate_prime++
+                if candidate_prime==0
+                    return 0        ; we wrapped; no more primes
+            }
+    
+            ; found next one, mark the multiples and return it.
+            sieve[candidate_prime] = true
+            uword multiple = candidate_prime
+    
+            while multiple < len(sieve) {
+                sieve[lsb(multiple)] = true
+                multiple += candidate_prime
+            }
+            return candidate_prime
        }
    }



-you get a program that outputs this when loaded on a C-64:

-![c64 screen](docs/source/_static/hello_screen.png)
+when compiled an ran on a C-64 you'll get:

+![c64 screen](docs/source/_static/primes_example.png)

 One of the included examples (wizzine.p8) animates a bunch of sprite balloons and looks like this:

@@ -109,3 +166,12 @@ Another example (cube3d-sprites.p8) draws the vertices of a rotating 3d cube:

 ![cube3d screen](docs/source/_static/cube3d.png)

+If you want to play a video game, a fully working Tetris clone is included in the examples:
+
+![tehtriz_screen](docs/source/_static/tehtriz.png)
+
+There are a couple of examples specially made for the CommanderX16 compiler target.
+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)
@@ -0,0 +1,10 @@
+plugins {
+    id "org.jetbrains.kotlin.jvm" version "$kotlinVersion" apply false
+}
+
+allprojects {
+    repositories {
+        mavenLocal()
+        mavenCentral()
+    }
+}
@@ -1,31 +0,0 @@
-#!/usr/bin/env bash
-
-echo "Compiling the parser..."
-java -jar ./parser/antlr/lib/antlr-4.7.2-complete.jar -o ./parser/src/prog8/parser -Xexact-output-dir -no-listener -no-visitor ./parser/antlr/prog8.g4
-
-
-PARSER_CLASSES=./out/production/parser
-COMPILER_JAR=prog8compiler.jar
-ANTLR_RUNTIME=./parser/antlr/lib/antlr-runtime-4.7.2.jar
-
-mkdir -p ${PARSER_CLASSES}
-javac  -d ${PARSER_CLASSES} -cp ${ANTLR_RUNTIME} ./parser/src/prog8/parser/prog8Lexer.java  ./parser/src/prog8/parser/prog8Parser.java
-
-echo "Compiling the compiler itself..."
-kotlinc -verbose -include-runtime -d ${COMPILER_JAR} -cp ${ANTLR_RUNTIME}:${PARSER_CLASSES} ./compiler/src/prog8
-
-echo "Finalizing the compiler jar file..."
-# add the antlr parser classes
-jar ufe ${COMPILER_JAR} prog8.CompilerMainKt -C ${PARSER_CLASSES} prog8
-
-# add the resources
-jar uf ${COMPILER_JAR} -C ./compiler/res .
-
-# add the antlr runtime classes
-rm -rf antlr_runtime_extraction
-mkdir antlr_runtime_extraction
-(cd antlr_runtime_extraction; jar xf ../${ANTLR_RUNTIME})
-jar uf ${COMPILER_JAR} -C antlr_runtime_extraction org
-rm -rf antlr_runtime_extraction
-
-echo "Done!"
@@ -0,0 +1,43 @@
+
+plugins {
+    id 'java'
+    id 'application'
+    id "org.jetbrains.kotlin.jvm"
+}
+
+java {
+    toolchain {
+        languageVersion = JavaLanguageVersion.of(javaVersion)
+    }
+}
+
+compileKotlin {
+    kotlinOptions {
+        jvmTarget = javaVersion
+    }
+}
+
+compileTestKotlin {
+    kotlinOptions {
+        jvmTarget = javaVersion
+    }
+}
+
+dependencies {
+    // should have no dependencies to other modules
+    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8"
+    implementation "com.michael-bull.kotlin-result:kotlin-result-jvm:1.1.18"
+}
+
+sourceSets {
+    main {
+        java {
+            srcDir "${project.projectDir}/src"
+        }
+        resources {
+            srcDir "${project.projectDir}/res"
+        }
+    }
+}
+
+// note: there are no unit tests in this module!
@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<module type="JAVA_MODULE" version="4">
+  <component name="NewModuleRootManager" inherit-compiler-output="true">
+    <exclude-output />
+    <content url="file://$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>
@@ -0,0 +1,24 @@
+package prog8.code
+
+/**
+ * By convention, the right side of an `Either` is used to hold successful values.
+ */
+sealed class Either<out L, out R> {
+
+    data class Left<out L>(val value: L) : Either<L, Nothing>()
+
+    data class Right<out R>(val value: R) : Either<Nothing, R>()
+
+    fun isRight() = this is Right<R>
+
+    fun isLeft() = this is Left<L>
+
+    inline fun <C> fold(ifLeft: (L) -> C, ifRight: (R) -> C): C = when (this) {
+        is Right -> ifRight(value)
+        is Left -> ifLeft(value)
+    }
+
+}
+
+fun <L> left(a: L) = Either.Left(a)
+fun <R> right(b: R) = Either.Right(b)
@@ -0,0 +1,256 @@
+package prog8.code
+
+import prog8.code.ast.PtNode
+import prog8.code.ast.PtProgram
+import prog8.code.core.*
+
+
+/**
+ * Tree structure containing all symbol definitions in the program
+ * (blocks, subroutines, variables (all types), memoryslabs, and labels).
+ */
+class SymbolTable(astProgram: PtProgram) : StNode(astProgram.name, StNodeType.GLOBAL, astProgram) {
+    /**
+     * The table as a flat mapping of scoped names to the StNode.
+     * This gives the fastest lookup possible (no need to traverse tree nodes)
+     */
+
+    private var cachedFlat: Map<String, StNode>? = null
+
+    val flat: Map<String, StNode> get()  {
+        if(cachedFlat!=null)
+            return cachedFlat!!
+
+        val result = mutableMapOf<String, StNode>()
+        fun collect(node: StNode) {
+            for(child in node.children) {
+                result[child.value.scopedName] = child.value
+                collect(child.value)
+            }
+        }
+        collect(this)
+        cachedFlat = result
+        return result
+    }
+
+    fun resetCachedFlat() {
+        cachedFlat = null
+    }
+
+    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 {
+        val vars = mutableListOf<StMemorySlab>()
+        fun collect(node: StNode) {
+            for(child in node.children) {
+                if(child.value.type== StNodeType.MEMORYSLAB)
+                    vars.add(child.value as StMemorySlab)
+                else
+                    collect(child.value)
+            }
+        }
+        collect(this)
+        vars
+    }
+
+    override fun lookup(scopedName: String) = flat[scopedName]
+
+    fun getLength(name: String): Int? {
+        val node = flat[name]
+        return when(node) {
+            is StMemVar -> node.length
+            is StMemorySlab -> node.size.toInt()
+            is StStaticVariable -> node.length
+            else -> null
+        }
+    }
+}
+
+
+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 astNode: PtNode,
+                  val children: MutableMap<String, StNode> = mutableMapOf()
+) {
+
+    lateinit var parent: StNode
+
+    val scopedName: String by lazy { scopedNameList.joinToString(".") }
+
+    open fun lookup(scopedName: String) =
+        lookup(scopedName.split('.'))
+
+    fun lookupUnscopedOrElse(name: String, default: () -> StNode) =
+        lookupUnscoped(name) ?: default()
+
+    fun lookupOrElse(scopedName: String, default: () -> StNode): StNode =
+        lookup(scopedName.split('.')) ?: default()
+
+    fun lookupUnscoped(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 add(child: StNode) {
+        children[child.name] = child
+        child.parent = this
+    }
+
+    private val scopedNameList: List<String> by lazy {
+        if(type==StNodeType.GLOBAL)
+            emptyList()
+        else
+            parent.scopedNameList + name
+    }
+
+    private fun lookup(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
+    }
+}
+
+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,    // used in the variable allocator
+                       astNode: PtNode) : StNode(name, StNodeType.STATICVAR, astNode) {
+
+    val uninitialized = onetimeInitializationArrayValue==null && onetimeInitializationStringValue==null && onetimeInitializationNumericValue==null
+
+    init {
+        if(length!=null) {
+            require(onetimeInitializationNumericValue == null)
+            if(onetimeInitializationArrayValue!=null)
+                require(onetimeInitializationArrayValue.isEmpty() ||onetimeInitializationArrayValue.size==length)
+        }
+        if(onetimeInitializationNumericValue!=null) {
+            require(dt in NumericDatatypes)
+        }
+        if(onetimeInitializationArrayValue!=null) {
+            require(dt in ArrayDatatypes)
+            require(length==onetimeInitializationArrayValue.size)
+        }
+        if(onetimeInitializationStringValue!=null) {
+            require(dt == DataType.STR)
+            require(length == onetimeInitializationStringValue.first.length+1)
+        }
+    }
+}
+
+
+class StConstant(name: String, val dt: DataType, val value: Double, astNode: PtNode) :
+    StNode(name, StNodeType.CONSTANT, astNode)
+
+
+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
+               astNode: PtNode) :
+    StNode(name, StNodeType.MEMVAR, astNode) {
+
+    init{
+        if(dt in ArrayDatatypes || dt == DataType.STR)
+            require(length!=null) { "memory mapped array or string must have known length" }
+    }
+}
+
+class StMemorySlab(
+    name: String,
+    val size: UInt,
+    val align: UInt,
+    astNode: PtNode
+):
+    StNode(name, StNodeType.MEMORYSLAB, astNode)
+
+
+class StSub(name: String, val parameters: List<StSubroutineParameter>, val returnType: DataType?, astNode: PtNode) :
+        StNode(name, StNodeType.SUBROUTINE, astNode)
+
+
+class StRomSub(name: String,
+               val address: UInt?,      // null in case of asmsub, specified in case of romsub
+               val parameters: List<StRomSubParameter>,
+               val returns: List<StRomSubParameter>,
+               astNode: PtNode) :
+    StNode(name, StNodeType.ROMSUB, astNode)
+
+
+
+class StSubroutineParameter(val name: String, val type: DataType)
+class StRomSubParameter(val register: RegisterOrStatusflag, val type: DataType)
+class StArrayElement(val number: Double?, val addressOfSymbol: String?)
+
+typealias StString = Pair<String, Encoding>
+typealias StArray = List<StArrayElement>
@@ -0,0 +1,206 @@
+package prog8.code
+
+import prog8.code.ast.*
+import prog8.code.core.*
+import prog8.code.target.VMTarget
+import java.util.*
+
+class SymbolTableMaker(private val program: PtProgram, private val options: CompilationOptions) {
+    fun make(): SymbolTable {
+        val st = SymbolTable(program)
+
+        BuiltinFunctions.forEach {
+            st.add(StNode(it.key, StNodeType.BUILTINFUNC, PtIdentifier(it.key, it.value.returnType ?: DataType.UNDEFINED, Position.DUMMY)))
+        }
+
+        val scopestack = Stack<StNode>()
+        scopestack.push(st)
+        program.children.forEach {
+            addToSt(it, scopestack)
+        }
+        require(scopestack.size==1)
+
+        if(options.compTarget.name != VMTarget.NAME) {
+            listOf(
+                PtMemMapped("P8ZP_SCRATCH_B1", DataType.UBYTE, options.compTarget.machine.zeropage.SCRATCH_B1, null, Position.DUMMY),
+                PtMemMapped("P8ZP_SCRATCH_REG", DataType.UBYTE, options.compTarget.machine.zeropage.SCRATCH_REG, null, Position.DUMMY),
+                PtMemMapped("P8ZP_SCRATCH_W1", DataType.UWORD, options.compTarget.machine.zeropage.SCRATCH_W1, null, Position.DUMMY),
+                PtMemMapped("P8ZP_SCRATCH_W2", DataType.UWORD, options.compTarget.machine.zeropage.SCRATCH_W2, null, Position.DUMMY),
+            ).forEach {
+                it.parent = program
+                st.add(StMemVar(it.name, it.type, it.address, it.arraySize?.toInt(), it))
+            }
+        }
+
+        return st
+    }
+
+    private fun addToSt(node: PtNode, scope: Stack<StNode>) {
+        val stNode = when(node) {
+            is PtAsmSub -> {
+                val parameters = node.parameters.map { StRomSubParameter(it.first, it.second.type) }
+                val returns = node.returns.map { StRomSubParameter(it.first, it.second) }
+                StRomSub(node.name, node.address, parameters, returns, node)
+            }
+            is PtBlock -> {
+                StNode(node.name, StNodeType.BLOCK, node)
+            }
+            is PtConstant -> {
+                StConstant(node.name, node.type, node.value, node)
+            }
+            is PtLabel -> {
+                StNode(node.name, StNodeType.LABEL, node)
+            }
+            is PtMemMapped -> {
+                StMemVar(node.name, node.type, node.address, node.arraySize?.toInt(), node)
+            }
+            is PtSub -> {
+                val params = node.parameters.map {StSubroutineParameter(it.name, it.type) }
+                StSub(node.name, params, node.returntype, node)
+            }
+            is PtVariable -> {
+                val initialNumeric: Double?
+                val initialString: StString?
+                val initialArray: StArray?
+                val numElements: Int?
+                val value = node.value
+                if(value!=null) {
+                    val number = (value as? PtNumber)?.number
+                    initialNumeric = if(number==0.0) null else number       // 0 as init value -> just uninitialized
+                    when (value) {
+                        is PtString -> {
+                            initialString = StString(value.value, value.encoding)
+                            initialArray = null
+                            numElements = value.value.length + 1   // include the terminating 0-byte
+                        }
+                        is PtArray -> {
+                            initialArray = makeInitialArray(value)
+                            initialString = null
+                            numElements = initialArray.size
+                            require(node.arraySize?.toInt()==numElements)
+                        }
+                        else -> {
+                            initialString = null
+                            initialArray = null
+                            numElements = node.arraySize?.toInt()
+                        }
+                    }
+                } else {
+                    initialNumeric = null
+                    initialArray = null
+                    initialString = null
+                    numElements = node.arraySize?.toInt()
+                }
+//                if(node.type in SplitWordArrayTypes) {
+//                    ... split array also add _lsb and _msb to symboltable?
+//                }
+                StStaticVariable(node.name, node.type, initialNumeric, initialString, initialArray, numElements, node.zeropage, node)
+            }
+            is PtBuiltinFunctionCall -> {
+                if(node.name=="memory") {
+                    // memory slab allocations are a builtin functioncall in the program, but end up named as well in the symboltable
+                    require(node.name.all { it.isLetterOrDigit() || it=='_' }) {"memory name should be a valid symbol name"}
+                    val slabname = (node.args[0] as PtString).value
+                    val size = (node.args[1] as PtNumber).number.toUInt()
+                    val align = (node.args[2] as PtNumber).number.toUInt()
+                    // don't add memory slabs in nested scope, just put them in the top level of the ST
+                    scope.firstElement().add(StMemorySlab("prog8_memoryslab_$slabname", size, align, node))
+                }
+                null
+            }
+            else -> null // node is not present in the ST
+        }
+
+        if(stNode!=null) {
+            scope.peek().add(stNode)
+            scope.push(stNode)
+        }
+        node.children.forEach {
+            addToSt(it, scope)
+        }
+        if(stNode!=null)
+            scope.pop()
+    }
+
+    private fun makeInitialArray(value: PtArray): List<StArrayElement> {
+        return value.children.map {
+            when(it) {
+                is PtAddressOf -> {
+                    if(it.isFromArrayElement)
+                        TODO("address-of array element $it in initial array value")
+                    StArrayElement(null, it.identifier.name)
+                }
+                is PtIdentifier -> StArrayElement(null, it.name)
+                is PtNumber -> StArrayElement(it.number, null)
+                else -> throw AssemblyError("invalid array element $it")
+            }
+        }
+    }
+
+}
+
+//    override fun visit(decl: VarDecl) {
+//        val node =
+//            when(decl.type) {
+//                VarDeclType.VAR -> {
+//                    var initialNumeric = (decl.value as? NumericLiteral)?.number
+//                    if(initialNumeric==0.0)
+//                        initialNumeric=null     // variable will go into BSS and this will be set to 0
+//                    val initialStringLit = decl.value as? StringLiteral
+//                    val initialString = if(initialStringLit==null) null else Pair(initialStringLit.value, initialStringLit.encoding)
+//                    val initialArrayLit = decl.value as? ArrayLiteral
+//                    val initialArray = makeInitialArray(initialArrayLit)
+//                    if(decl.isArray && decl.datatype !in ArrayDatatypes)
+//                        throw FatalAstException("array vardecl has mismatched dt ${decl.datatype}")
+//                    val numElements =
+//                        if(decl.isArray)
+//                            decl.arraysize!!.constIndex()
+//                        else if(initialStringLit!=null)
+//                            initialStringLit.value.length+1  // include the terminating 0-byte
+//                        else
+//                            null
+//                    val bss = if(decl.datatype==DataType.STR)
+//                        false
+//                    else if(decl.isArray)
+//                        initialArray.isNullOrEmpty()
+//                    else
+//                        initialNumeric == null
+//                    val astNode = PtVariable(decl.name, decl.datatype, null, null, decl.position)
+//                    StStaticVariable(decl.name, decl.datatype, bss, initialNumeric, initialString, initialArray, numElements, decl.zeropage, astNode, decl.position)
+//                }
+//                VarDeclType.CONST -> {
+//                    val astNode = PtVariable(decl.name, decl.datatype, null, null, decl.position)
+//                    StConstant(decl.name, decl.datatype, (decl.value as NumericLiteral).number, astNode, decl.position)
+//                }
+//                VarDeclType.MEMORY -> {
+//                    val numElements =
+//                        if(decl.datatype in ArrayDatatypes)
+//                            decl.arraysize!!.constIndex()
+//                        else null
+//                    val astNode = PtVariable(decl.name, decl.datatype, null, null, decl.position)
+//                    StMemVar(decl.name, decl.datatype, (decl.value as NumericLiteral).number.toUInt(), numElements, astNode, decl.position)
+//                }
+//            }
+//        scopestack.peek().add(node)
+//        // st.origAstLinks[decl] = node
+//    }
+//
+//    private fun makeInitialArray(arrayLit: ArrayLiteral?): StArray? {
+//        if(arrayLit==null)
+//            return null
+//        return arrayLit.value.map {
+//            when(it){
+//                is AddressOf -> {
+//                    val scopedName = it.identifier.targetNameAndType(program).first
+//                    StArrayElement(null, scopedName)
+//                }
+//                is IdentifierReference -> {
+//                    val scopedName = it.targetNameAndType(program).first
+//                    StArrayElement(null, scopedName)
+//                }
+//                is NumericLiteral -> StArrayElement(it.number, null)
+//                else -> throw FatalAstException("weird element dt in array literal")
+//            }
+//        }.toList()
+//    }
+//
@@ -0,0 +1,121 @@
+package prog8.code.ast
+
+import prog8.code.core.IMemSizer
+import prog8.code.core.IStringEncoding
+import prog8.code.core.Position
+import prog8.code.core.SourceCode
+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 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)
+    fun definingISub() = findParentNode<IPtSubroutine>(this)
+}
+
+
+class PtNodeGroup : PtNode(Position.DUMMY)
+
+
+sealed class PtNamedNode(var name: String, position: Position): PtNode(position) {
+    // Note that as an exception, the 'name' is not read-only
+    // but a var. This is to allow for cheap node renames.
+    val scopedName: String
+        get() {
+            var namedParent: PtNode = this.parent
+            return if(namedParent is PtProgram)
+                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 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" || it.name=="p8_main" }
+            ?.children
+            ?.firstOrNull { it is PtSub && (it.name == "start" || it.name=="main.start" || it.name=="p8_start" || it.name=="p8_main.p8_start") } as PtSub?
+}
+
+
+class PtBlock(name: String,
+              val address: UInt?,
+              val library: Boolean,
+              val forceOutput: Boolean,
+              val noSymbolPrefixing: Boolean,
+              val veraFxMuls: Boolean,
+              val alignment: BlockAlignment,
+              val source: SourceCode,       // taken from the module the block is defined in.
+              position: Position
+) : PtNamedNode(name, position) {
+    enum class BlockAlignment {
+        NONE,
+        WORD,
+        PAGE
+    }
+}
+
+
+class PtInlineAssembly(val assembly: String, val isIR: Boolean, position: Position) : PtNode(position) {
+    init {
+        require(!assembly.startsWith('\n') && !assembly.startsWith('\r')) { "inline assembly should be trimmed" }
+        require(!assembly.endsWith('\n') && !assembly.endsWith('\r')) { "inline assembly should be trimmed" }
+    }
+}
+
+
+class PtLabel(name: String, position: Position) : PtNamedNode(name, position)
+
+
+class PtBreakpoint(position: Position): PtNode(position)
+
+
+class PtIncludeBinary(val file: Path, val offset: UInt?, val length: UInt?, position: Position) : PtNode(position)
+
+
+class PtNop(position: Position): PtNode(position)
+
+
+// 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
+}
@@ -0,0 +1,319 @@
+package prog8.code.ast
+
+import prog8.code.core.*
+import java.util.*
+import kotlin.math.abs
+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")
+            }
+        }
+    }
+
+    infix fun isSameAs(other: PtExpression): Boolean {
+        return when(this) {
+            is PtAddressOf -> {
+                if(other !is PtAddressOf)
+                    return false
+                if (other.type!==type || !(other.identifier isSameAs identifier))
+                    return false
+                if(other.children.size!=children.size)
+                    return false
+                if(children.size==1)
+                    return true
+                return arrayIndexExpr!! isSameAs other.arrayIndexExpr!!
+            }
+            is PtArrayIndexer -> other is PtArrayIndexer && other.type==type && other.variable isSameAs variable && other.index isSameAs index && other.splitWords==splitWords
+            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.name==name
+            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
+        }
+    }
+
+    infix fun isSameAs(target: PtAssignTarget): Boolean {
+        return when {
+            target.memory != null && this is PtMemoryByte-> {
+                target.memory!!.address isSameAs this.address
+            }
+            target.identifier != null && this is PtIdentifier -> {
+                this.name == target.identifier!!.name
+            }
+            target.array != null && this is PtArrayIndexer -> {
+                this.variable.name == target.array!!.variable.name && this.index isSameAs target.array!!.index && this.splitWords==target.array!!.splitWords
+            }
+            else -> false
+        }
+    }
+
+    fun asConstInteger(): Int? = (this as? PtNumber)?.number?.toInt()
+
+    fun isSimple(): Boolean {
+        return when(this) {
+            is PtAddressOf -> true
+            is PtArray -> true
+            is PtArrayIndexer -> index is PtNumber || index is PtIdentifier
+            is PtBinaryExpression -> false
+            is PtBuiltinFunctionCall -> name in arrayOf("msb", "lsb", "peek", "peekw", "mkword", "set_carry", "set_irqd", "clear_carry", "clear_irqd")
+            is PtContainmentCheck -> false
+            is PtFunctionCall -> false
+            is PtIdentifier -> true
+            is PtMachineRegister -> true
+            is PtMemoryByte -> address is PtNumber || address is PtIdentifier
+            is PtNumber -> true
+            is PtPrefix -> value.isSimple()
+            is PtRange -> true
+            is PtString -> true
+            is PtTypeCast -> value.isSimple()
+        }
+    }
+
+    /*
+    fun clone(): PtExpression {
+        fun withClonedChildrenFrom(orig: PtExpression, clone: PtExpression): PtExpression {
+            orig.children.forEach { clone.add((it as PtExpression).clone()) }
+            return clone
+        }
+        when(this) {
+            is PtAddressOf -> return withClonedChildrenFrom(this, PtAddressOf(position))
+            is PtArray -> return withClonedChildrenFrom(this, PtArray(type, position))
+            is PtArrayIndexer -> return withClonedChildrenFrom(this, PtArrayIndexer(type, position))
+            is PtBinaryExpression -> return withClonedChildrenFrom(this, PtBinaryExpression(operator, type, position))
+            is PtBuiltinFunctionCall -> return withClonedChildrenFrom(this, PtBuiltinFunctionCall(name, void, hasNoSideEffects, type, position))
+            is PtContainmentCheck -> return withClonedChildrenFrom(this, PtContainmentCheck(position))
+            is PtFunctionCall -> return withClonedChildrenFrom(this, PtFunctionCall(name, void, type, position))
+            is PtIdentifier -> return withClonedChildrenFrom(this, PtIdentifier(name, type, position))
+            is PtMachineRegister -> return withClonedChildrenFrom(this, PtMachineRegister(register, type, position))
+            is PtMemoryByte -> return withClonedChildrenFrom(this, PtMemoryByte(position))
+            is PtNumber -> return withClonedChildrenFrom(this, PtNumber(type, number, position))
+            is PtPrefix -> return withClonedChildrenFrom(this, PtPrefix(operator, type, position))
+            is PtRange -> return withClonedChildrenFrom(this, PtRange(type, position))
+            is PtString -> return withClonedChildrenFrom(this, PtString(value, encoding, position))
+            is PtTypeCast -> return withClonedChildrenFrom(this, PtTypeCast(type, position))
+        }
+    }
+    */
+}
+
+class PtAddressOf(position: Position) : PtExpression(DataType.UWORD, position) {
+    val identifier: PtIdentifier
+        get() = children[0] as PtIdentifier
+    val arrayIndexExpr: PtExpression?
+        get() = if(children.size==2) children[1] as PtExpression else null
+
+    val isFromArrayElement: Boolean
+        get() = children.size==2
+}
+
+
+class PtArrayIndexer(elementType: DataType, position: Position): PtExpression(elementType, position) {
+    val variable: PtIdentifier
+        get() = children[0] as PtIdentifier
+    val index: PtExpression
+        get() = children[1] as PtExpression
+
+    val splitWords: Boolean
+        get() = variable.type in SplitWordArrayTypes
+
+    val usesPointerVariable: Boolean
+        get() = variable.type==DataType.UWORD
+
+    init {
+        require(elementType in NumericDatatypes)
+    }
+}
+
+
+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
+    }
+
+    val size: Int
+        get() = children.size
+}
+
+
+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 }
+}
+
+
+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
+}
+
+
+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 name: 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 }
+}
+
+
+class PtIdentifier(val name: String, type: DataType, position: Position) : PtExpression(type, position) {
+    override fun toString(): String {
+        return "[PtIdentifier:$name $type $position]"
+    }
+
+    fun copy() = PtIdentifier(name, type, position)
+}
+
+
+class PtMemoryByte(position: Position) : PtExpression(DataType.UBYTE, position) {
+    val address: PtExpression
+        get() = children.single() as PtExpression
+}
+
+
+class PtNumber(type: DataType, val number: Double, position: Position) : PtExpression(type, position) {
+
+    companion object {
+        fun fromBoolean(bool: Boolean, position: Position): PtNumber =
+            PtNumber(DataType.UBYTE, if(bool) 1.0 else 0.0, position)
+    }
+
+    init {
+        if(type==DataType.BOOL)
+            throw IllegalArgumentException("bool should have become ubyte @$position")
+        if(type!=DataType.FLOAT) {
+            val rounded = round(number)
+            if (rounded != number)
+                throw IllegalArgumentException("refused rounding of float to avoid loss of precision @$position")
+        }
+    }
+
+    override fun hashCode(): Int = Objects.hash(type, number)
+
+    override fun equals(other: Any?): Boolean {
+        if(other==null || other !is PtNumber)
+            return false
+        return number==other.number
+    }
+
+    operator fun compareTo(other: PtNumber): Int = number.compareTo(other.number)
+
+    override fun toString() = "PtNumber:$type:$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
+        require(operator in setOf("+", "-", "~")) { "invalid prefix operator: $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
+
+    fun toConstantIntegerRange(): IntProgression? {
+        fun makeRange(fromVal: Int, toVal: Int, stepVal: Int): IntProgression {
+            return when {
+                fromVal <= toVal -> when {
+                    stepVal <= 0 -> IntRange.EMPTY
+                    stepVal == 1 -> fromVal..toVal
+                    else -> fromVal..toVal step stepVal
+                }
+                else -> when {
+                    stepVal >= 0 -> IntRange.EMPTY
+                    stepVal == -1 -> fromVal downTo toVal
+                    else -> fromVal downTo toVal step abs(stepVal)
+                }
+            }
+        }
+
+        val fromLv = from as? PtNumber
+        val toLv = to as? PtNumber
+        val stepLv = step as? PtNumber
+        if(fromLv==null || toLv==null || stepLv==null)
+            return null
+        val fromVal = fromLv.number.toInt()
+        val toVal = toLv.number.toInt()
+        val stepVal = stepLv.number.toInt()
+        return makeRange(fromVal, toVal, stepVal)
+    }
+}
+
+
+class PtString(val value: String, val encoding: Encoding, position: Position) : PtExpression(DataType.STR, position) {
+    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 in the Intermediate Code
+class PtMachineRegister(val register: Int, type: DataType, position: Position) : PtExpression(type, position)
+
+
+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
@@ -0,0 +1,163 @@
+package prog8.code.ast
+
+import prog8.code.core.*
+
+/**
+ * Produces readable text from a [PtNode] (AST node, usually starting with PtProgram as root),
+ * passing it as a String to the specified receiver function.
+ */
+fun printAst(root: PtNode, skipLibraries: Boolean, output: (text: String) -> Unit) {
+    fun type(dt: DataType) = "!${dt.name.lowercase()}!"
+    fun txt(node: PtNode): String {
+        return when(node) {
+            is PtAssignTarget -> "<target>"
+            is PtAssignment -> "<assign>"
+            is PtAugmentedAssign -> "<inplace-assign> ${node.operator}"
+            is PtBreakpoint -> "%breakpoint"
+            is PtConditionalBranch -> "if_${node.condition.name.lowercase()}"
+            is PtAddressOf -> "&"
+            is PtArray -> "array len=${node.children.size} ${type(node.type)}"
+            is PtArrayIndexer -> "<arrayindexer> ${type(node.type)} ${if(node.splitWords) "[splitwords]" else ""}"
+            is PtBinaryExpression -> "<expr> ${node.operator} ${type(node.type)}"
+            is PtBuiltinFunctionCall -> {
+                val str = if(node.void) "void " else ""
+                str + node.name + "()"
+            }
+            is PtContainmentCheck -> "in"
+            is PtFunctionCall -> {
+                val str = if(node.void) "void " else ""
+                str + node.name + "()"
+            }
+            is PtIdentifier -> "${node.name} ${type(node.type)}"
+            is PtMachineRegister -> "VMREG#${node.register} ${type(node.type)}"
+            is PtMemoryByte -> "@()"
+            is PtNumber -> {
+                val numstr = if(node.type == DataType.FLOAT) node.number.toString() else node.number.toHex()
+                "$numstr ${type(node.type)}"
+            }
+            is PtPrefix -> node.operator
+            is PtRange -> "<range>"
+            is PtString -> "\"${node.value.escape()}\""
+            is PtTypeCast -> "as ${node.type.name.lowercase()}"
+            is PtForLoop -> "for"
+            is PtIfElse -> "ifelse"
+            is PtIncludeBinary -> "%incbin '${node.file}', ${node.offset}, ${node.length}"
+            is PtInlineAssembly -> {
+                if(node.isIR)
+                    "%ir {{ ...${node.assembly.length} characters... }}"
+                else
+                    "%asm {{ ...${node.assembly.length} characters... }}"
+            }
+            is PtJump -> {
+                if(node.identifier!=null)
+                    "goto ${node.identifier.name}"
+                else if(node.address!=null)
+                    "goto ${node.address.toHex()}"
+                else if(node.generatedLabel!=null)
+                    "goto ${node.generatedLabel}"
+                else
+                    "???"
+            }
+            is PtAsmSub -> {
+                val params = if (node.parameters.isEmpty()) "" else "...TODO ${node.parameters.size} PARAMS..."
+                val clobbers = if (node.clobbers.isEmpty()) "" else "clobbers ${node.clobbers}"
+                val returns = if (node.returns.isEmpty()) "" else (if (node.returns.size == 1) "-> ${node.returns[0].second.name.lowercase()}" else "-> ${node.returns.map { it.second.name.lowercase() }}")
+                val str = if (node.inline) "inline " else ""
+                if(node.address==null) {
+                    str + "asmsub ${node.name}($params) $clobbers $returns"
+                } else {
+                    str + "romsub ${node.address.toHex()} = ${node.name}($params) $clobbers $returns"
+                }
+            }
+            is PtBlock -> {
+                val addr = if(node.address==null) "" else "@${node.address.toHex()}"
+                val align = if(node.alignment==PtBlock.BlockAlignment.NONE) "" else "align=${node.alignment}"
+                "\nblock '${node.name}' $addr $align"
+            }
+            is PtConstant -> {
+                val value = if(node.type in IntegerDatatypes) node.value.toInt().toString() else node.value.toString()
+                "const ${node.type.name.lowercase()} ${node.name} = $value"
+            }
+            is PtLabel -> "${node.name}:"
+            is PtMemMapped -> {
+                if(node.type in ArrayDatatypes) {
+                    val arraysize = if(node.arraySize==null) "" else node.arraySize.toString()
+                    val eltType = ArrayToElementTypes.getValue(node.type)
+                    "&${eltType.name.lowercase()}[$arraysize] ${node.name} = ${node.address.toHex()}"
+                } else {
+                    "&${node.type.name.lowercase()} ${node.name} = ${node.address.toHex()}"
+                }
+            }
+            is PtSub -> {
+                val params = if (node.parameters.isEmpty()) "" else "...TODO ${node.parameters.size} PARAMS..."
+                var str = "sub ${node.name}($params) "
+                if(node.returntype!=null)
+                    str += "-> ${node.returntype.name.lowercase()}"
+                str
+            }
+            is PtVariable -> {
+                val split = if(node.type in SplitWordArrayTypes) "@split" else ""
+                val str = if(node.arraySize!=null) {
+                    val eltType = ArrayToElementTypes.getValue(node.type)
+                    "${eltType.name.lowercase()}[${node.arraySize}] $split ${node.name}"
+                }
+                else if(node.type in ArrayDatatypes) {
+                    val eltType = ArrayToElementTypes.getValue(node.type)
+                    "${eltType.name.lowercase()}[] $split ${node.name}"
+                }
+                else
+                    "${node.type.name.lowercase()} ${node.name}"
+                if(node.value!=null)
+                    str + " = " + txt(node.value)
+                else
+                    str
+            }
+            is PtNodeGroup -> "<group>"
+            is PtNop -> "nop"
+            is PtPostIncrDecr -> "<post> ${node.operator}"
+            is PtProgram -> "PROGRAM ${node.name}"
+            is PtRepeatLoop -> "repeat"
+            is PtReturn -> "return"
+            is PtSubroutineParameter -> "${node.type.name.lowercase()} ${node.name}"
+            is PtWhen -> "when"
+            is PtWhenChoice -> {
+                if(node.isElse)
+                    "else"
+                else
+                    "->"
+            }
+        }
+    }
+
+    if(root is PtProgram) {
+        output(txt(root))
+        root.children.forEach {
+            walkAst(it) { node, depth ->
+                val txt = txt(node)
+                val library = if(node is PtBlock) node.library else node.definingBlock()?.library==true
+                if(!library || !skipLibraries) {
+                    if (txt.isNotEmpty())
+                        output("    ".repeat(depth) + txt(node))
+                }
+            }
+        }
+        println()
+    } else {
+        walkAst(root) { node, depth ->
+            val txt = txt(node)
+            val library = if(node is PtBlock) node.library else node.definingBlock()?.library==true
+            if(!library || !skipLibraries) {
+                if (txt.isNotEmpty())
+                    output("    ".repeat(depth) + txt(node))
+            }
+        }
+    }
+}
+
+fun walkAst(root: PtNode, act: (node: PtNode, depth: Int) -> Unit) {
+    fun recurse(node: PtNode, depth: Int) {
+        act(node, depth)
+        node.children.forEach { recurse(it, depth+1) }
+    }
+    recurse(root, 0)
+}
@@ -0,0 +1,172 @@
+package prog8.code.ast
+
+import prog8.code.core.*
+
+
+sealed interface IPtSubroutine {
+    val name: String
+}
+
+class PtAsmSub(
+    name: String,
+    val address: UInt?,
+    val clobbers: Set<CpuRegister>,
+    val parameters: List<Pair<RegisterOrStatusflag, PtSubroutineParameter>>,
+    val returns: List<Pair<RegisterOrStatusflag, DataType>>,
+    val inline: Boolean,
+    position: Position
+) : PtNamedNode(name, position), IPtSubroutine
+
+
+class PtSub(
+    name: String,
+    val parameters: List<PtSubroutineParameter>,
+    val returntype: DataType?,
+    position: Position
+) : PtNamedNode(name, position), IPtSubroutine {
+    init {
+        // params and return value should not be str
+        if(parameters.any{ it.type !in NumericDatatypes })
+            throw AssemblyError("non-numeric parameter")
+        if(returntype!=null && returntype !in NumericDatatypes)
+            throw AssemblyError("non-numeric returntype $returntype")
+        parameters.forEach { it.parent=this }
+    }
+}
+
+
+class PtSubroutineParameter(name: String, val type: DataType, position: Position): PtNamedNode(name, position)
+
+
+sealed interface IPtAssignment {
+    val children: MutableList<PtNode>
+    val target: PtAssignTarget
+        get() = children[0] as PtAssignTarget
+    val value: PtExpression
+        get() = children[1] as PtExpression
+}
+
+class PtAssignment(position: Position) : PtNode(position), IPtAssignment
+
+class PtAugmentedAssign(val operator: String, position: Position) : PtNode(position), IPtAssignment
+
+
+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")
+            }
+        }
+
+    infix fun isSameAs(expression: PtExpression): Boolean = expression.isSameAs(this)
+}
+
+
+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
+}
+
+
+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
+}
+
+
+class PtIfElse(position: Position) : PtNode(position) {
+    val condition: PtExpression
+        get() = children[0] as PtExpression
+    val ifScope: PtNodeGroup
+        get() = children[1] as PtNodeGroup
+    val elseScope: PtNodeGroup
+        get() = children[2] as PtNodeGroup
+}
+
+
+class PtJump(val identifier: PtIdentifier?,
+             val address: UInt?,
+             val generatedLabel: String?,
+             position: Position) : PtNode(position) {
+    init {
+        identifier?.let {it.parent = this }
+    }
+}
+
+
+class PtPostIncrDecr(val operator: String, position: Position) : PtNode(position) {
+    val target: PtAssignTarget
+        get() = children.single() as PtAssignTarget
+}
+
+
+class PtRepeatLoop(position: Position) : PtNode(position) {
+    val count: PtExpression
+        get() = children[0] as PtExpression
+    val statements: PtNodeGroup
+        get() = children[1] as PtNodeGroup
+}
+
+
+class PtReturn(position: Position) : PtNode(position) {
+    val hasValue = children.any()
+    val value: PtExpression?
+        get() {
+            return if(children.any())
+                children.single() as PtExpression
+            else
+                null
+        }
+}
+
+
+sealed interface IPtVariable {
+    val name: String
+    val type: DataType
+}
+
+
+class PtVariable(name: String, override val type: DataType, val zeropage: ZeropageWish, val value: PtExpression?, val arraySize: UInt?, position: Position) : PtNamedNode(name, position), IPtVariable {
+    init {
+        value?.let {it.parent=this}
+    }
+}
+
+
+class PtConstant(name: String, override val type: DataType, val value: Double, position: Position) : PtNamedNode(name, position), IPtVariable
+
+
+class PtMemMapped(name: String, override val type: DataType, val address: UInt, val arraySize: UInt?, position: Position) : PtNamedNode(name, position), IPtVariable
+
+
+class PtWhen(position: Position) : PtNode(position) {
+    val value: PtExpression
+        get() = children[0] as PtExpression
+    val choices: PtNodeGroup
+        get() = children[1] as PtNodeGroup
+}
+
+
+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
+}
@@ -0,0 +1,136 @@
+package prog8.code.core
+
+class ReturnConvention(val dt: DataType?, val reg: RegisterOrPair?, val floatFac1: Boolean)
+class ParamConvention(val dt: DataType, val reg: RegisterOrPair?, val variable: Boolean)
+class CallConvention(val params: List<ParamConvention>, val returns: ReturnConvention) {
+    override fun toString(): String {
+        val paramConvs =  params.mapIndexed { index, it ->
+            when {
+                it.reg!=null -> "$index:${it.reg}"
+                it.variable -> "$index:variable"
+                else -> "$index:???"
+            }
+        }
+        val returnConv =
+            when {
+                returns.reg!=null -> returns.reg.toString()
+                returns.floatFac1 -> "floatFAC1"
+                else -> "<no returnvalue>"
+            }
+        return "CallConvention[" + paramConvs.joinToString() + " ; returns: $returnConv]"
+    }
+}
+
+class FParam(val name: String, val possibleDatatypes: Array<DataType>)
+
+class FSignature(val pure: Boolean,      // does it have side effects?
+                      val parameters: List<FParam>,
+                      val returnType: DataType?) {
+
+    fun callConvention(actualParamTypes: List<DataType>): CallConvention {
+        val returns: ReturnConvention = when (returnType) {
+            DataType.UBYTE, DataType.BYTE -> ReturnConvention(returnType, RegisterOrPair.A, false)
+            DataType.UWORD, DataType.WORD -> ReturnConvention(returnType, RegisterOrPair.AY, false)
+            DataType.FLOAT -> ReturnConvention(returnType, null, true)
+            in PassByReferenceDatatypes -> ReturnConvention(returnType!!, RegisterOrPair.AY, false)
+            null -> ReturnConvention(null, null, false)
+            else -> {
+                // return type depends on arg type
+                when (val paramType = actualParamTypes.first()) {
+                    DataType.UBYTE, DataType.BYTE -> ReturnConvention(paramType, RegisterOrPair.A, false)
+                    DataType.UWORD, DataType.WORD -> ReturnConvention(paramType, RegisterOrPair.AY, false)
+                    DataType.FLOAT -> ReturnConvention(paramType, null, true)
+                    in PassByReferenceDatatypes -> ReturnConvention(paramType, RegisterOrPair.AY, false)
+                    else -> ReturnConvention(paramType, null, false)
+                }
+            }
+        }
+
+        return when {
+            actualParamTypes.isEmpty() -> CallConvention(emptyList(), returns)
+            actualParamTypes.size==1 -> {
+                // one parameter goes via register/registerpair
+                val paramConv = when(val paramType = actualParamTypes[0]) {
+                    DataType.UBYTE, DataType.BYTE -> ParamConvention(paramType, RegisterOrPair.A, false)
+                    DataType.UWORD, DataType.WORD -> ParamConvention(paramType, RegisterOrPair.AY, false)
+                    DataType.FLOAT -> ParamConvention(paramType, RegisterOrPair.AY, false)
+                    in PassByReferenceDatatypes -> ParamConvention(paramType, RegisterOrPair.AY, false)
+                    else -> ParamConvention(paramType, null, false)
+                }
+                CallConvention(listOf(paramConv), returns)
+            }
+            else -> {
+                // multiple parameters go via variables
+                val paramConvs = actualParamTypes.map { ParamConvention(it, null, true) }
+                CallConvention(paramConvs, returns)
+            }
+        }
+    }
+}
+
+val BuiltinFunctions: Map<String, FSignature> = mapOf(
+    // this set of function have no return value and operate in-place:
+    "setlsb"    to FSignature(false, listOf(FParam("variable", arrayOf(DataType.WORD, DataType.UWORD)), FParam("value", arrayOf(DataType.BYTE, DataType.UBYTE))), null),
+    "setmsb"    to FSignature(false, listOf(FParam("variable", arrayOf(DataType.WORD, DataType.UWORD)), FParam("value", arrayOf(DataType.BYTE, DataType.UBYTE))), null),
+    "rol"       to FSignature(false, listOf(FParam("item", arrayOf(DataType.UBYTE, DataType.UWORD))), null),
+    "ror"       to FSignature(false, listOf(FParam("item", arrayOf(DataType.UBYTE, DataType.UWORD))), null),
+    "rol2"      to FSignature(false, listOf(FParam("item", arrayOf(DataType.UBYTE, DataType.UWORD))), null),
+    "ror2"      to FSignature(false, listOf(FParam("item", arrayOf(DataType.UBYTE, DataType.UWORD))), null),
+    "sort"      to FSignature(false, listOf(FParam("array", ArrayDatatypes)), null),
+    "reverse"   to FSignature(false, listOf(FParam("array", ArrayDatatypes)), null),
+    // cmp returns a status in the carry flag, but not a proper return value
+    "cmp"       to FSignature(false, listOf(FParam("value1", IntegerDatatypesNoBool), FParam("value2", NumericDatatypesNoBool)), null),
+    "prog8_lib_stringcompare"     to FSignature(true, listOf(FParam("str1", arrayOf(DataType.STR)), FParam("str2", arrayOf(DataType.STR))), DataType.BYTE),
+    "prog8_lib_square_byte"       to FSignature(true, listOf(FParam("value", arrayOf(DataType.BYTE, DataType.UBYTE))), DataType.UBYTE),
+    "prog8_lib_square_word"       to FSignature(true, listOf(FParam("value", arrayOf(DataType.WORD, DataType.UWORD))), DataType.UWORD),
+    "abs"       to FSignature(true, listOf(FParam("value", NumericDatatypesNoBool)), null),
+    "abs__byte"  to FSignature(true, listOf(FParam("value", arrayOf(DataType.BYTE))), DataType.BYTE),
+    "abs__word"  to FSignature(true, listOf(FParam("value", arrayOf(DataType.WORD))), DataType.WORD),
+    "abs__float" to FSignature(true, listOf(FParam("value", arrayOf(DataType.FLOAT))), DataType.FLOAT),
+    "len"       to FSignature(true, listOf(FParam("values", IterableDatatypes)), DataType.UWORD),
+    // normal functions follow:
+    "sizeof"    to FSignature(true, listOf(FParam("object", DataType.entries.toTypedArray())), DataType.UBYTE),
+    "sgn"       to FSignature(true, listOf(FParam("value", NumericDatatypesNoBool)), DataType.BYTE),
+    "sqrt"        to FSignature(true, listOf(FParam("value", NumericDatatypesNoBool)), null),
+    "sqrt__ubyte" to FSignature(true, listOf(FParam("value", arrayOf(DataType.UBYTE))), DataType.UBYTE),
+    "sqrt__uword" to FSignature(true, listOf(FParam("value", arrayOf(DataType.UWORD))), DataType.UBYTE),
+    "sqrt__float" to FSignature(true, listOf(FParam("value", arrayOf(DataType.FLOAT))), DataType.FLOAT),
+    "divmod"           to FSignature(false, listOf(FParam("number", arrayOf(DataType.UBYTE, DataType.UWORD)), FParam("divident", arrayOf(DataType.UBYTE, DataType.UWORD)), FParam("division", arrayOf(DataType.UBYTE, DataType.UWORD)), FParam("remainder", arrayOf(DataType.UBYTE, DataType.UWORD))), null),
+    "divmod__ubyte"    to FSignature(false, listOf(FParam("number", arrayOf(DataType.UBYTE)), FParam("divident", arrayOf(DataType.UBYTE)), FParam("division", arrayOf(DataType.UBYTE)), FParam("remainder", arrayOf(DataType.UBYTE))), null),
+    "divmod__uword"    to FSignature(false, listOf(FParam("number", arrayOf(DataType.UWORD)), FParam("divident", arrayOf(DataType.UWORD)), FParam("division", arrayOf(DataType.UWORD)), FParam("remainder", arrayOf(DataType.UWORD))), null),
+    "any"       to FSignature(true, listOf(FParam("values", ArrayDatatypes)), DataType.UBYTE),
+    "all"       to FSignature(true, listOf(FParam("values", ArrayDatatypes)), DataType.UBYTE),
+    "lsb"       to FSignature(true, listOf(FParam("value", arrayOf(DataType.UWORD, DataType.WORD))), DataType.UBYTE),
+    "msb"       to FSignature(true, listOf(FParam("value", arrayOf(DataType.UWORD, DataType.WORD))), DataType.UBYTE),
+    "mkword"    to FSignature(true, listOf(FParam("msb", arrayOf(DataType.UBYTE)), FParam("lsb", arrayOf(DataType.UBYTE))), DataType.UWORD),
+    "clamp"     to FSignature(true, listOf(FParam("value", arrayOf(DataType.BYTE)), FParam("minimum", arrayOf(DataType.BYTE)), FParam("maximum", arrayOf(DataType.BYTE))), null),
+    "clamp__byte"  to FSignature(true, listOf(FParam("value", arrayOf(DataType.BYTE)), FParam("minimum", arrayOf(DataType.BYTE)), FParam("maximum", arrayOf(DataType.BYTE))), DataType.BYTE),
+    "clamp__ubyte" to FSignature(true, listOf(FParam("value", arrayOf(DataType.UBYTE)), FParam("minimum", arrayOf(DataType.UBYTE)), FParam("maximum", arrayOf(DataType.UBYTE))), DataType.UBYTE),
+    "clamp__word"  to FSignature(true, listOf(FParam("value", arrayOf(DataType.WORD)), FParam("minimum", arrayOf(DataType.WORD)), FParam("maximum", arrayOf(DataType.WORD))), DataType.WORD),
+    "clamp__uword" to FSignature(true, listOf(FParam("value", arrayOf(DataType.UWORD)), FParam("minimum", arrayOf(DataType.UWORD)), FParam("maximum", arrayOf(DataType.UWORD))), DataType.UWORD),
+    "min"        to FSignature(true, listOf(FParam("val1", arrayOf(DataType.BYTE)), FParam("val2", arrayOf(DataType.BYTE))), null),
+    "min__byte"  to FSignature(true, listOf(FParam("val1", arrayOf(DataType.BYTE)), FParam("val2", arrayOf(DataType.BYTE))), DataType.BYTE),
+    "min__ubyte" to FSignature(true, listOf(FParam("val1", arrayOf(DataType.UBYTE)), FParam("val2", arrayOf(DataType.UBYTE))), DataType.UBYTE),
+    "min__word"  to FSignature(true, listOf(FParam("val1", arrayOf(DataType.WORD)), FParam("val2", arrayOf(DataType.WORD))), DataType.WORD),
+    "min__uword" to FSignature(true, listOf(FParam("val1", arrayOf(DataType.UWORD)), FParam("val2", arrayOf(DataType.UWORD))), DataType.UWORD),
+    "max"        to FSignature(true, listOf(FParam("val1", arrayOf(DataType.BYTE)), FParam("val2", arrayOf(DataType.BYTE))), null),
+    "max__byte"  to FSignature(true, listOf(FParam("val1", arrayOf(DataType.BYTE)), FParam("val2", arrayOf(DataType.BYTE))), DataType.BYTE),
+    "max__ubyte" to FSignature(true, listOf(FParam("val1", arrayOf(DataType.UBYTE)), FParam("val2", arrayOf(DataType.UBYTE))), DataType.UBYTE),
+    "max__word"  to FSignature(true, listOf(FParam("val1", arrayOf(DataType.WORD)), FParam("val2", arrayOf(DataType.WORD))), DataType.WORD),
+    "max__uword" to FSignature(true, listOf(FParam("val1", arrayOf(DataType.UWORD)), FParam("val2", arrayOf(DataType.UWORD))), DataType.UWORD),
+    "peek"      to FSignature(true, listOf(FParam("address", arrayOf(DataType.UWORD))), DataType.UBYTE),
+    "peekw"     to FSignature(true, listOf(FParam("address", arrayOf(DataType.UWORD))), DataType.UWORD),
+    "poke"      to FSignature(false, listOf(FParam("address", arrayOf(DataType.UWORD)), FParam("value", arrayOf(DataType.UBYTE))), null),
+    "pokew"     to FSignature(false, listOf(FParam("address", arrayOf(DataType.UWORD)), FParam("value", arrayOf(DataType.UWORD))), null),
+    "pokemon"   to FSignature(false, listOf(FParam("address", arrayOf(DataType.UWORD)), FParam("value", arrayOf(DataType.UBYTE))), DataType.UBYTE),
+    "pop"       to FSignature(false, listOf(FParam("target", ByteDatatypes)), null),
+    "popw"      to FSignature(false, listOf(FParam("target", WordDatatypes)), null),
+    "push"      to FSignature(false, listOf(FParam("value", ByteDatatypes)), null),
+    "pushw"     to FSignature(false, listOf(FParam("value", WordDatatypes)), null),
+    "rsave"     to FSignature(false, emptyList(), null),
+    "rrestore"  to FSignature(false, emptyList(), null),
+    "memory"    to FSignature(true, listOf(FParam("name", arrayOf(DataType.STR)), FParam("size", arrayOf(DataType.UWORD)), FParam("alignment", arrayOf(DataType.UWORD))), DataType.UWORD),
+    "callfar"   to FSignature(false, listOf(FParam("bank", arrayOf(DataType.UBYTE)), FParam("address", arrayOf(DataType.UWORD)), FParam("arg", arrayOf(DataType.UWORD))), DataType.UWORD),
+)
+
+val InplaceModifyingBuiltinFunctions = setOf("setlsb", "setmsb", "rol", "ror", "rol2", "ror2", "sort", "reverse")
@@ -0,0 +1,36 @@
+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 zpAllowed: 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 warnSymbolShadowing: Boolean = false,
+                         var optimize: Boolean = false,
+                         var asmQuiet: Boolean = false,
+                         var asmListfile: Boolean = false,
+                         var includeSourcelines: Boolean = false,
+                         var experimentalCodegen: Boolean = false,
+                         var varsHighBank: Int? = null,
+                         var splitWordArrays: Boolean = false,
+                         var breakpointCpuInstruction: Boolean = false,
+                         var outputDir: Path = Path(""),
+                         var symbolDefs: Map<String, String> = emptyMap()
+) {
+    init {
+        compTarget.machine.initializeMemoryAreas(this)
+    }
+
+    companion object {
+        val AllZeropageAllowed: List<UIntRange> = listOf(0u..255u)
+    }
+}
@@ -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("")
+}
@@ -0,0 +1,200 @@
+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_UW_SPLIT,     // pass by reference, lo/hi byte split
+    ARRAY_W,            // pass by reference
+    ARRAY_W_SPLIT,      // pass by reference, lo/hi byte split
+    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 fromCpuRegister(cpu: CpuRegister): RegisterOrPair {
+            return when(cpu) {
+                CpuRegister.A -> A
+                CpuRegister.X -> X
+                CpuRegister.Y -> Y
+            }
+        }
+    }
+
+    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_UW_SPLIT, DataType.ARRAY_W, DataType.ARRAY_W_SPLIT, DataType.ARRAY_F, DataType.ARRAY_BOOL)
+val StringlyDatatypes = arrayOf(DataType.STR, DataType.ARRAY_UB, DataType.ARRAY_B, DataType.UWORD)
+val SplitWordArrayTypes = arrayOf(DataType.ARRAY_UW_SPLIT, DataType.ARRAY_W_SPLIT)
+val IterableDatatypes = arrayOf(
+    DataType.STR,
+    DataType.ARRAY_UB, DataType.ARRAY_B,
+    DataType.ARRAY_UW, DataType.ARRAY_W,
+    DataType.ARRAY_UW_SPLIT, DataType.ARRAY_W_SPLIT,
+    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_W_SPLIT to DataType.WORD,
+    DataType.ARRAY_UW_SPLIT 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
+)
+
+val CpuRegisters = setOf(
+    RegisterOrPair.A, RegisterOrPair.X, RegisterOrPair.Y,
+    RegisterOrPair.AX, RegisterOrPair.AY, RegisterOrPair.XY
+)
+
+
+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
+}
@@ -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)
@@ -0,0 +1,17 @@
+package prog8.code.core
+
+import prog8.code.SymbolTable
+import prog8.code.ast.PtProgram
+
+interface ICodeGeneratorBackend {
+    fun generate(program: PtProgram,
+                 symbolTable: SymbolTable,
+                 options: CompilationOptions,
+                 errors: IErrorReporter): IAssemblyProgram?
+}
+
+
+interface IAssemblyProgram {
+    val name: String
+    fun assemble(options: CompilationOptions, errors: IErrorReporter): Boolean
+}
@@ -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: Iterable<UByte>, encoding: Encoding): String
+}
@@ -0,0 +1,13 @@
+package prog8.code.core
+
+interface IErrorReporter {
+    fun err(msg: String, position: Position)
+    fun warn(msg: String, position: Position)
+    fun undefined(symbol: List<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.")
+    }
+}
@@ -0,0 +1,30 @@
+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
+    val PROGRAM_LOAD_ADDRESS : UInt
+    val BSSHIGHRAM_START: UInt
+    val BSSHIGHRAM_END: UInt
+
+    val cpu: CpuType
+    var zeropage: Zeropage
+    var golden: GoldenRam
+
+    fun initializeMemoryAreas(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
+}
@@ -0,0 +1,6 @@
+package prog8.code.core
+
+interface IMemSizer {
+    fun memorySize(dt: DataType): Int
+    fun memorySize(arrayDt: DataType, numElements: Int): Int
+}
@@ -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: Iterable<UByte>, encoding: Encoding): String
+}
@@ -0,0 +1,173 @@
+package prog8.code.core
+
+import com.github.michaelbull.result.Err
+import com.github.michaelbull.result.Ok
+import com.github.michaelbull.result.Result
+
+
+class MemAllocationError(message: String) : Exception(message)
+
+
+abstract class MemoryAllocator(protected val options: CompilationOptions) {
+    data class VarAllocation(val address: UInt, val dt: DataType, val size: Int)
+
+    abstract fun allocate(name: String,
+                          datatype: DataType,
+                          numElements: Int?,
+                          position: Position?,
+                          errors: IErrorReporter): Result<VarAllocation, MemAllocationError>
+}
+
+
+abstract class Zeropage(options: CompilationOptions): MemoryAllocator(options) {
+
+    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
+
+
+    // the variables allocated into Zeropage.
+    // name (scoped) ==> pair of address to (Datatype + bytesize)
+    val allocatedVariables = mutableMapOf<String, VarAllocation>()
+
+    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 retainAllowed() {
+        synchronized(this) {
+            for(allowed in options.zpAllowed)
+                free.retainAll { it in allowed }
+        }
+    }
+
+    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 }
+    }
+
+    override fun allocate(name: String,
+                          datatype: DataType,
+                          numElements: Int?,
+                          position: Position?,
+                          errors: IErrorReporter): Result<VarAllocation, MemAllocationError> {
+
+        require(name.isEmpty() || name !in allocatedVariables) {"name can't be allocated twice"}
+
+        if(options.zeropage== ZeropageType.DONTUSE)
+            return Err(MemAllocationError("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(MemAllocationError("floating point option not enabled"))
+                    }
+                    else -> throw MemAllocationError("weird dt")
+                }
+
+        synchronized(this) {
+            if(free.size > 0) {
+                if(size==1) {
+                    for(candidate in free.minOrNull()!! .. free.maxOrNull()!!+1u) {
+                        if(oneSeparateByteFree(candidate))
+                            return Ok(VarAllocation(makeAllocation(candidate, 1, datatype, name), datatype,1))
+                    }
+                    return Ok(VarAllocation(makeAllocation(free[0], 1, datatype, name), datatype,1))
+                }
+                for(candidate in free.minOrNull()!! .. free.maxOrNull()!!+1u) {
+                    if (sequentialFree(candidate, size))
+                        return Ok(VarAllocation(makeAllocation(candidate, size, datatype, name), datatype, size))
+                }
+            }
+        }
+
+        return Err(MemAllocationError("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: String): UInt {
+        require(size>=0)
+        free.removeAll(address until address+size.toUInt())
+        if(name.isNotEmpty()) {
+            allocatedVariables[name] = when(datatype) {
+                in NumericDatatypes -> VarAllocation(address, datatype, size)        // numerical variables in zeropage never have an initial value here because they are set in separate initializer assignments
+                DataType.STR -> VarAllocation(address, datatype, size)
+                in ArrayDatatypes -> VarAllocation(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()
+}
+
+
+// TODO: this class is not yet used
+class GoldenRam(options: CompilationOptions, val region: UIntRange): MemoryAllocator(options) {
+    private var nextLocation: UInt = region.first
+
+    override fun allocate(
+        name: String,
+        datatype: DataType,
+        numElements: Int?,
+        position: Position?,
+        errors: IErrorReporter): Result<VarAllocation, MemAllocationError> {
+
+        val size: Int =
+            when (datatype) {
+                in IntegerDatatypes -> options.compTarget.memorySize(datatype)
+                DataType.STR, in ArrayDatatypes  -> {
+                    options.compTarget.memorySize(datatype, numElements!!)
+                }
+                DataType.FLOAT -> {
+                    if (options.floats) {
+                        options.compTarget.memorySize(DataType.FLOAT)
+                    } else return Err(MemAllocationError("floating point option not enabled"))
+                }
+                else -> throw MemAllocationError("weird dt")
+            }
+
+        return if(nextLocation<=region.last && (region.last + 1u - nextLocation) >= size.toUInt()) {
+            val result = Ok(VarAllocation(nextLocation, datatype, size))
+            nextLocation += size.toUInt()
+            result
+        } else
+            Err(MemAllocationError("no more free space in Golden RAM to allocate $size sequential bytes"))
+    }
+}
@@ -0,0 +1,20 @@
+package prog8.code.core
+
+val AssociativeOperators = setOf("+", "*", "&", "|", "^", "==", "!=")
+val ComparisonOperators = setOf("==", "!=", "<", ">", "<=", ">=")
+val LogicalOperators = setOf("and", "or", "xor", "not")
+val AugmentAssignmentOperators = setOf("+", "-", "/", "*", "&", "|", "^", "<<", ">>", "%", "and", "or", "xor")
+val BitwiseOperators = setOf("&", "|", "^", "~")
+val PrefixOperators = setOf("+", "-", "~", "not")
+// val InvalidOperatorsForBoolean = setOf("+", "-", "*", "/", "%", "<<", ">>") + BitwiseOperators
+
+fun invertedComparisonOperator(operator: String) =
+    when (operator) {
+        "==" -> "!="
+        "!=" -> "=="
+        "<" -> ">="
+        ">" -> "<="
+        "<=" -> ">"
+        ">=" -> "<"
+        else -> null
+    }
@@ -0,0 +1,27 @@
+package prog8.code.core
+
+import prog8.code.core.SourceCode.Companion.LIBRARYFILEPREFIX
+import java.nio.file.InvalidPathException
+import kotlin.io.path.Path
+import kotlin.io.path.absolute
+
+data class Position(val file: String, val line: Int, val startCol: Int, val endCol: Int) {
+    override fun toString(): String = "[$file: line $line col ${startCol+1}-${endCol+1}]"
+    fun toClickableStr(): String {
+        if(this===DUMMY)
+            return ""
+        if(file.startsWith(LIBRARYFILEPREFIX))
+            return "$file:$line:$startCol:"
+        return try {
+            val path = Path(file).absolute().normalize().toString()
+            "file://$path:$line:$startCol:"
+        } catch(x: InvalidPathException) {
+            // this can occur on Windows when the source origin contains "invalid" characters such as ':'
+            "file://$file:$line:$startCol:"
+        }
+    }
+
+    companion object {
+        val DUMMY = Position("~dummy~", 0, 0, 0)
+    }
+}
@@ -0,0 +1,3 @@
+package prog8.code.core
+
+data class RegisterOrStatusflag(val registerOrPair: RegisterOrPair?, val statusflag: Statusflag?)
@@ -0,0 +1,173 @@
+package prog8.code.core
+
+import java.io.File
+import java.io.IOException
+import java.nio.file.Path
+import kotlin.io.path.Path
+import kotlin.io.path.readText
+
+
+const val internedStringsModuleName = "prog8_interned_strings"
+
+
+/**
+ * Encapsulates - and ties together - actual source code (=text) and its [origin].
+ */
+sealed class SourceCode {
+
+    /**
+     * Whether this [SourceCode] instance was created as a [Resource]
+     */
+    abstract val isFromResources: Boolean
+
+    /**
+     * Whether this [SourceCode] instance was created as a [File]
+     */
+    abstract val isFromFilesystem: Boolean
+
+    /**
+     * The logical name of the source code unit. Usually the module's name.
+     */
+    abstract val name: String
+
+    /**
+     * Where this [SourceCode] instance came from.
+     * This can be one of the following:
+     * * a normal string representation of a [java.nio.file.Path], if it originates from a file (see [File])
+     * * `string:44c56085` if was created via [String]
+     * * `library:/x/y/z.ext` if it is a library file that was loaded from resources (see [Resource])
+     */
+    abstract val origin: String
+
+    /**
+     * The source code as plain string.
+     */
+    abstract val text: String
+
+    /**
+     * Printable representation, deliberately does NOT return the actual text.
+     */
+    final override fun toString() = "${this.javaClass.name}[${this.origin}]"
+
+    companion object {
+
+        /**
+         * filename prefix to designate library files that will be retreived from internal resources rather than disk
+         */
+        const val LIBRARYFILEPREFIX = "library:"
+        const val STRINGSOURCEPREFIX = "string:"
+        val curdir: Path = Path(".").toAbsolutePath()
+        fun relative(path: Path): Path = curdir.relativize(path.toAbsolutePath())
+        fun isRegularFilesystemPath(pathString: String) =
+            !(pathString.startsWith(LIBRARYFILEPREFIX) || pathString.startsWith(STRINGSOURCEPREFIX))
+
+        fun isLibraryResource(path: String) = path.startsWith(LIBRARYFILEPREFIX)
+    }
+
+    /**
+     * Turn a plain String into a [SourceCode] object.
+     * [origin] will be something like `string:44c56085`.
+     */
+    class Text(override val text: String): SourceCode() {
+        override val isFromResources = false
+        override val isFromFilesystem = false
+        override val origin = "$STRINGSOURCEPREFIX${System.identityHashCode(text).toString(16)}"
+        override val name = "<unnamed-text>"
+    }
+
+    /**
+     * Get [SourceCode] from the file represented by the specified Path.
+     * This immediately reads the file fully into memory.
+     *
+     * [origin] will be the given path in absolute and normalized form.
+     * @throws NoSuchFileException if the file does not exist
+     * @throws FileSystemException if the file cannot be read
+     */
+    class File(path: Path): SourceCode() {
+        override val text: String
+        override val origin: String
+        override val name: String
+        override val isFromResources = false
+        override val isFromFilesystem = true
+
+        init {
+            val normalized = path.normalize()
+            origin = relative(normalized).toString()
+            try {
+                text = normalized.readText()
+                name = normalized.toFile().nameWithoutExtension
+            } catch (nfx: java.nio.file.NoSuchFileException) {
+                throw NoSuchFileException(normalized.toFile()).also { it.initCause(nfx) }
+            } catch (iox: IOException) {
+                throw FileSystemException(normalized.toFile()).also { it.initCause(iox) }
+            }
+        }
+    }
+
+    /**
+     * [origin]: `library:/x/y/z.p8` for a given `pathString` of "x/y/z.p8"
+     */
+    class Resource(pathString: String): SourceCode() {
+        private val normalized = "/" + Path(pathString).normalize().toMutableList().joinToString("/")
+
+        override val isFromResources = true
+        override val isFromFilesystem = false
+        override val origin = "$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(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>"
+    }
+}
+
+
+object SourceLineCache {
+    private val cache = mutableMapOf<String, List<String>>()
+
+    private fun getCachedFile(file: String): List<String> {
+        val existing = cache[file]
+        if(existing!=null)
+            return existing
+        if (SourceCode.isRegularFilesystemPath(file)) {
+            val source = SourceCode.File(Path(file))
+            cache[file] = source.text.split('\n', '\r').map { it.trim() }
+            return cache.getValue(file)
+        } else if(file.startsWith(SourceCode.LIBRARYFILEPREFIX)) {
+            val source = SourceCode.Resource(file.drop(SourceCode.LIBRARYFILEPREFIX.length))
+            cache[file] = source.text.split('\n', '\r').map { it.trim()}
+            return cache.getValue(file)
+        }
+        return emptyList()
+    }
+
+    fun retrieveLine(position: Position): String? {
+        if (position.line>0) {
+            val lines = getCachedFile(position.file)
+            if(lines.isNotEmpty())
+                return lines[position.line-1]
+        }
+        return null
+    }
+}
@@ -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
+}
@@ -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"
+    }
+}
@@ -0,0 +1,22 @@
+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"
+
+        fun viceMonListName(baseFilename: String) = "$baseFilename.vice-mon-list"
+    }
+}
@@ -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"
+    }
+}
@@ -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: Iterable<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 }
+        )
+    }
+}
@@ -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.pet.PETMachineDefinition
+
+
+class PETTarget: ICompilationTarget, IStringEncoding by Encoder, IMemSizer by CbmMemorySizer {
+    override val name = NAME
+    override val machine = PETMachineDefinition()
+    override val supportedEncodings = setOf(Encoding.PETSCII, Encoding.SCREENCODES)
+    override val defaultEncoding = Encoding.PETSCII
+
+    companion object {
+        const val NAME = "pet32"
+    }
+}
@@ -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
+}
@@ -0,0 +1,63 @@
+package prog8.code.target.atari
+
+import prog8.code.core.*
+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
+
+    override val BSSHIGHRAM_START = 0u    // TODO
+    override val BSSHIGHRAM_END = 0u      // TODO
+
+    override lateinit var zeropage: Zeropage
+    override lateinit var golden: GoldenRam
+
+    override fun getFloatAsmBytes(num: Number) = TODO("atari 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 initializeMemoryAreas(compilerOptions: CompilationOptions) {
+        zeropage = AtariZeropage(compilerOptions)
+        golden = GoldenRam(compilerOptions, UIntRange.EMPTY)
+    }
+}
@@ -0,0 +1,57 @@
+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) {
+            throw InternalCompilerException("Atari target doesn't yet support floating point routines")
+        }
+
+        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 distinctFree = free.distinct()
+        free.clear()
+        free.addAll(distinctFree)
+
+        removeReservedFromFreePool()
+        retainAllowed()
+    }
+
+    override fun allocateCx16VirtualRegisters() {
+        TODO("Not known if atari can put the virtual regs in ZP")
+    }
+}
@@ -0,0 +1,54 @@
+package prog8.code.target.c128
+
+import prog8.code.core.*
+import prog8.code.target.C64Target
+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
+
+    override val BSSHIGHRAM_START = 0u    // TODO
+    override val BSSHIGHRAM_END = 0u      // TODO
+
+    override lateinit var zeropage: Zeropage
+    override lateinit var golden: GoldenRam
+
+    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 = C64Target.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 initializeMemoryAreas(compilerOptions: CompilationOptions) {
+        zeropage = C128Zeropage(compilerOptions)
+        golden = GoldenRam(compilerOptions, UIntRange.EMPTY)    // TODO does the c128 have some of this somewhere?
+    }
+}
@@ -0,0 +1,78 @@
+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
+
+
+// reference: "Mapping the C128" zero page chapter.
+
+class C128Zeropage(options: CompilationOptions) : Zeropage(options) {
+
+    override val SCRATCH_B1 = 0x74u      // temp storage for a single byte
+    override val SCRATCH_REG = 0x75u     // 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) {
+            throw InternalCompilerException("C128 target doesn't yet support floating point routines")
+            // note: in git commit labeled 'c128: remove floats module' the floats.p8 and floats.asm files are removed,
+            //       they could be retrieved again at a later time if the compiler somehow *does* store the fp variables in bank1.
+        }
+
+        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 -> {
+                // $00/$01 are data port IO registers, // $02-$09 are storage locations for JSRFAR and such
+                free.addAll(0x0au..0xffu)
+                free.removeAll(listOf(0x90u, 0x91u, 0xa0u, 0xa1u, 0xa2u, 0xc0u, 0xccu, 0xcdu, 0xd0u, 0xd1u, 0xd2u, 0xd3u, 0xd4u, 0xd5u, 0xf7u))        // these are updated/used by IRQ
+            }
+            ZeropageType.KERNALSAFE -> {
+                free.addAll(0x0au..0x8fu)       // BASIC variables
+                free.addAll(listOf(0x92u, 0x96u, 0x9bu, 0x9cu, 0x9eu, 0x9fu, 0xa4u, 0xa7u, 0xa8u, 0xa9u, 0xaau, 0xabu,
+                    0xb0u, 0xb1u, 0xb4u, 0xb5u, 0xb6u))
+            }
+            ZeropageType.FLOATSAFE,
+            ZeropageType.BASICSAFE -> {
+                free.addAll(listOf(0x0bu, 0x0cu, 0x0du, 0x0eu, 0x0fu, 0x10u, 0x11u, 0x12u, 0x16u, 0x17u, 0x18u, 0x19u, 0x1au))
+                free.addAll(0x1bu..0x23u)
+                free.addAll(listOf(0x3fu, 0x40u, 0x41u, 0x42u, 0x43u, 0x44u, 0x47u, 0x48u, 0x49u, 0x4au, 0x4bu, 0x4cu, 0x4fu,
+                    0x55u, 0x56u, 0x57u, 0x58u,
+                    0x74u, 0x75u, 0x78u, 0x80u, 0x83u, 0x87u, 0x88u, 0x89u, 0x8au, 0x8bu, 0x8cu, 0x8du, 0x8eu, 0x8fu,
+                    0x92u, 0x96u, 0x9bu, 0x9cu, 0x9eu, 0x9fu, 0xa4u, 0xa7u, 0xa8u, 0xa9u, 0xaau, 0xabu,
+                    0xb0u, 0xb1u, 0xb4u, 0xb5u, 0xb6u
+                ))
+
+                // if(options.zeropage==ZeropageType.BASICSAFE) {
+                    // can also clobber the FP locations (unconditionally, because the C128 target doesn't support floating point calculations in prog8 at this time0
+                    free.addAll(listOf(0x14u, 0x28u, 0x29u, 0x2au, 0x2bu, 0x2cu,
+                        0x50u, 0x51u, 0x52u, 0x53u, 0x54u, 0x59u, 0x5au, 0x5bu, 0x5cu, 0x5du, 0x5eu, 0x5fu, 0x60u, 0x61u, 0x62u,
+                        0x63u, 0x64u, 0x65u, 0x66u, 0x67u, 0x68u,
+                        0x6au, 0x6bu, 0x6cu, 0x6du, 0x6eu, 0x6fu, 0x71u))
+                // }
+            }
+            ZeropageType.DONTUSE -> {
+                free.clear()  // don't use zeropage at all
+            }
+        }
+
+        val distinctFree = free.distinct()
+        free.clear()
+        free.addAll(distinctFree)
+
+        removeReservedFromFreePool()
+        retainAllowed()
+    }
+
+    override fun allocateCx16VirtualRegisters() {
+        TODO("Not known if C128 can put the virtual regs in ZP")
+    }
+}
@@ -0,0 +1,64 @@
+package prog8.code.target.c64
+
+import prog8.code.core.*
+import prog8.code.target.C64Target
+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
+
+    override val BSSHIGHRAM_START = 0xc000u
+    override val BSSHIGHRAM_END = 0xd000u
+
+    override lateinit var zeropage: Zeropage
+    override lateinit var golden: GoldenRam
+
+    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 $emulator...")
+            val viceMonlist = C64Target.viceMonListName(programNameWithPath.toString())
+            val cmdline = listOf(emulator, "-silent", "-moncommands", viceMonlist,
+                    "-autostartprgmode", "1", "-autostart-warp", "-autostart", "${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 initializeMemoryAreas(compilerOptions: CompilationOptions) {
+        zeropage = C64Zeropage(compilerOptions)
+        golden = GoldenRam(compilerOptions, 0xc000u until 0xd000u)
+    }
+
+}
@@ -0,0 +1,98 @@
+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, 0x05, 0x06, 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, 0xa6,
+                        0xb0, 0xb1, 0xbe, 0xbf, 0xf9).map{it.toUInt()})
+            } else {
+                // don't use the zeropage at all
+                free.clear()
+            }
+        }
+
+        val distinctFree = free.distinct()
+        free.clear()
+        free.addAll(distinctFree)
+
+        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()
+        }
+
+        retainAllowed()
+    }
+
+    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 ($02).
+        for(reg in 0..15) {
+            allocatedVariables["cx16.r${reg}"]   = VarAllocation((4+reg*2).toUInt(), DataType.UWORD, 2)       // cx16.r0 .. cx16.r15
+            allocatedVariables["cx16.r${reg}s"]  = VarAllocation((4+reg*2).toUInt(), DataType.WORD, 2)        // cx16.r0s .. cx16.r15s
+            allocatedVariables["cx16.r${reg}L"]  = VarAllocation((4+reg*2).toUInt(), DataType.UBYTE, 1)       // cx16.r0L .. cx16.r15L
+            allocatedVariables["cx16.r${reg}H"]  = VarAllocation((5+reg*2).toUInt(), DataType.UBYTE, 1)       // cx16.r0H .. cx16.r15H
+            allocatedVariables["cx16.r${reg}sL"] = VarAllocation((4+reg*2).toUInt(), DataType.BYTE, 1)        // cx16.r0sL .. cx16.r15sL
+            allocatedVariables["cx16.r${reg}sH"] = VarAllocation((5+reg*2).toUInt(), DataType.BYTE, 1)        // cx16.r0sH .. cx16.r15sH
+            free.remove((4+reg*2).toUInt())
+            free.remove((5+reg*2).toUInt())
+        }
+    }
+}
@@ -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: Iterable<UByte>): Result<String, CharConversionException> {
+        return Ok(bytes.map { decodeTable[it.toInt()] }.joinToString(""))
+    }
+}
@@ -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
+}
@@ -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: Iterable<UByte>): Result<String, CharConversionException> {
+        return try {
+            Ok(String(bytes.map { it.toByte() }.toByteArray(), charset))
+        } catch (ce: CharConversionException) {
+            Err(ce)
+        }
+    }
+}
@@ -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"
+    }
+}
@@ -0,0 +1,66 @@
+package prog8.code.target.cx16
+
+import prog8.code.core.*
+import prog8.code.target.C64Target
+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
+
+    override val BSSHIGHRAM_START = 0xa000u     // hiram bank 1, 8Kb, assumed to be active
+    override val BSSHIGHRAM_END = 0xc000u       // rom starts here.
+
+    override lateinit var zeropage: Zeropage
+    override lateinit var golden: GoldenRam
+
+    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", C64Target.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()
+        processb.environment()["PULSE_LATENCY_MSEC"] = "10"
+        val process: Process = processb.start()
+        process.waitFor()
+    }
+
+    override fun isIOAddress(address: UInt): Boolean = address==0u || address==1u || address in 0x9f00u..0x9fffu
+
+    override fun initializeMemoryAreas(compilerOptions: CompilationOptions) {
+        zeropage = CX16Zeropage(compilerOptions)
+        golden = GoldenRam(compilerOptions, 0x0400u until 0x0800u)
+    }
+
+}
@@ -0,0 +1,68 @@
+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+$7f
+
+
+    init {
+        if (options.floats && options.zeropage !in arrayOf(
+                ZeropageType.FLOATSAFE,
+                ZeropageType.BASICSAFE,
+                ZeropageType.DONTUSE
+            ))
+            throw InternalCompilerException("when floats are enabled, zero page type should be 'floatsafe' or 'basicsafe' or 'dontuse'")
+
+        // the addresses 0x02 to 0x21 (inclusive) are taken for sixteen virtual 16-bit api registers.
+
+        synchronized(this) {
+            when (options.zeropage) {
+                ZeropageType.FULL -> {
+                    free.addAll(0x22u..0xffu)
+                }
+                ZeropageType.KERNALSAFE -> {
+                    free.addAll(0x22u..0x7fu)
+                    free.addAll(0xa9u..0xffu)
+                }
+                ZeropageType.FLOATSAFE -> {
+                    free.addAll(0x22u..0x7fu)
+                    free.addAll(0xd4u..0xffu)
+                }
+                ZeropageType.BASICSAFE -> {
+                    free.addAll(0x22u..0x7fu)
+                }
+                ZeropageType.DONTUSE -> {
+                    free.clear() // don't use zeropage at all
+                }
+            }
+
+            val distinctFree = free.distinct()
+            free.clear()
+            free.addAll(distinctFree)
+
+            removeReservedFromFreePool()
+            allocateCx16VirtualRegisters()
+            retainAllowed()
+        }
+    }
+
+    override fun allocateCx16VirtualRegisters() {
+        // Note: the 16 virtual registers R0-R15 are not regular allocated variables, they're *memory mapped* elsewhere to fixed addresses.
+        // However, to be able for the compiler to "see" them as zero page variables, we have to register them here as well.
+        // This is important because the compiler sometimes treats ZP variables more efficiently (for example if it's a pointer)
+        for(reg in 0..15) {
+            allocatedVariables["cx16.r${reg}"]   = VarAllocation((2+reg*2).toUInt(), DataType.UWORD, 2)       // cx16.r0 .. cx16.r15
+            allocatedVariables["cx16.r${reg}s"]  = VarAllocation((2+reg*2).toUInt(), DataType.WORD, 2)        // cx16.r0s .. cx16.r15s
+            allocatedVariables["cx16.r${reg}L"]  = VarAllocation((2+reg*2).toUInt(), DataType.UBYTE, 1)       // cx16.r0L .. cx16.r15L
+            allocatedVariables["cx16.r${reg}H"]  = VarAllocation((3+reg*2).toUInt(), DataType.UBYTE, 1)       // cx16.r0H .. cx16.r15H
+            allocatedVariables["cx16.r${reg}sL"] = VarAllocation((2+reg*2).toUInt(), DataType.BYTE, 1)        // cx16.r0sL .. cx16.r15sL
+            allocatedVariables["cx16.r${reg}sH"] = VarAllocation((3+reg*2).toUInt(), DataType.BYTE, 1)        // cx16.r0sH .. cx16.r15sH
+        }
+    }
+}
@@ -0,0 +1,55 @@
+package prog8.code.target.pet
+
+import prog8.code.core.*
+import prog8.code.target.C64Target
+import prog8.code.target.cbm.Mflpt5
+import java.nio.file.Path
+
+
+class PETMachineDefinition: IMachineDefinition {
+
+    override val cpu = CpuType.CPU6502
+
+    override val FLOAT_MAX_POSITIVE = Mflpt5.FLOAT_MAX_POSITIVE
+    override val FLOAT_MAX_NEGATIVE = Mflpt5.FLOAT_MAX_NEGATIVE
+    override val FLOAT_MEM_SIZE = Mflpt5.FLOAT_MEM_SIZE
+    override val PROGRAM_LOAD_ADDRESS = 0x0401u
+
+    override val BSSHIGHRAM_START = 0xffffu
+    override val BSSHIGHRAM_END = 0xffffu
+
+    override lateinit var zeropage: Zeropage
+    override lateinit var golden: GoldenRam
+
+    override fun getFloatAsmBytes(num: Number) = Mflpt5.fromNumber(num).makeFloatFillAsm()
+
+    override fun importLibs(compilerOptions: CompilationOptions, compilationTargetName: String): List<String> {
+        return if (compilerOptions.launcher == CbmPrgLauncherType.BASIC || compilerOptions.output == OutputType.PRG)
+            listOf("syslib")
+        else
+            emptyList()
+    }
+
+    override fun launchEmulator(selectedEmulator: Int, programNameWithPath: Path) {
+        if(selectedEmulator!=1) {
+            System.err.println("The pet target only supports the main emulator (Vice).")
+            return
+        }
+
+        println("\nStarting PET emulator...")
+        val viceMonlist = C64Target.viceMonListName(programNameWithPath.toString())
+        val cmdline = listOf("xpet", "-model", "4032", "-ramsize", "32", "-videosize", "40", "-silent", "-moncommands", viceMonlist,
+                "-autostartprgmode", "1", "-autostart-warp", "-autostart", "${programNameWithPath}.prg")
+        val processb = ProcessBuilder(cmdline).inheritIO()
+        val process=processb.start()
+        process.waitFor()
+    }
+
+    override fun isIOAddress(address: UInt): Boolean = address in 0xe800u..0xe8ffu
+
+    override fun initializeMemoryAreas(compilerOptions: CompilationOptions) {
+        zeropage = PETZeropage(compilerOptions)
+        // there's no golden ram.
+    }
+
+}
@@ -0,0 +1,59 @@
+package prog8.code.target.pet
+
+import prog8.code.core.CompilationOptions
+import prog8.code.core.InternalCompilerException
+import prog8.code.core.Zeropage
+import prog8.code.core.ZeropageType
+
+
+// reference: http://www.zimmers.net/cbmpics/cbm/PETx/petmem.txt
+
+class PETZeropage(options: CompilationOptions) : Zeropage(options) {
+
+    override val SCRATCH_B1 = 0xb3u      // temp storage for a single byte
+    override val SCRATCH_REG = 0xb4u     // temp storage for a register, must be B1+1
+    override val SCRATCH_W1 = 0xb6u      // temp storage 1 for a word
+    override val SCRATCH_W2 = 0xb8u      // temp storage 2 for a word
+
+    init {
+        if (options.floats) {
+            throw InternalCompilerException("PET target doesn't yet support floating point routines")
+        }
+
+        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 -> {
+                free.addAll(0x00u..0xffu)
+                free.removeAll(listOf(0x8du, 0x8eu, 0x8fu, 0x97u, 0x98u, 0x99u, 0x9au, 0x9bu, 0x9eu, 0xa7u, 0xa8u, 0xa9u, 0xaau))        // these are updated/used by IRQ
+            }
+            ZeropageType.KERNALSAFE -> {
+                free.addAll(0x00u..0xffu)
+                free.removeAll(listOf(0x8du, 0x8eu, 0x8fu, 0x97u, 0x98u, 0x99u, 0x9au, 0x9bu, 0x9eu, 0xa7u, 0xa8u, 0xa9u, 0xaau))        // these are updated/used by IRQ
+            }
+            ZeropageType.FLOATSAFE,
+            ZeropageType.BASICSAFE -> {
+                free.addAll(0xb3u..0xbau)       // TODO more?
+            }
+            ZeropageType.DONTUSE -> {
+                free.clear()  // don't use zeropage at all
+            }
+        }
+
+        val distinctFree = free.distinct()
+        free.clear()
+        free.addAll(distinctFree)
+
+        removeReservedFromFreePool()
+        retainAllowed()
+    }
+
+    override fun allocateCx16VirtualRegisters() {
+        TODO("Not known if PET can put the virtual regs in ZP")
+    }
+}
@@ -0,0 +1,73 @@
+package prog8.code.target.virtual
+
+import prog8.code.core.*
+import java.nio.file.Path
+import kotlin.io.path.isReadable
+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 val BSSHIGHRAM_START = 0u          // not actually used
+    override val BSSHIGHRAM_END = 0u            // not actually used
+    override lateinit var zeropage: Zeropage    // not actually used
+    override lateinit var golden: GoldenRam     // not actually used
+
+    override fun getFloatAsmBytes(num: Number): String {
+        // little endian binary representation
+        val bits = num.toFloat().toBits().toUInt()
+        val hexStr = bits.toString(16).padStart(8, '0')
+        val parts = hexStr.chunked(2).map { "\$" + it }
+        return parts.joinToString(", ")
+    }
+
+    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 in our own module, we launch the virtual machine via reflection
+        val vm = Class.forName("prog8.vm.VmRunner").getDeclaredConstructor().newInstance() as IVirtualMachineRunner
+        val filename = programNameWithPath.name
+        if(programNameWithPath.isReadable()) {
+            vm.runProgram(programNameWithPath.readText())
+        } else {
+            val withExt = programNameWithPath.resolveSibling("$filename.p8ir")
+            if(withExt.isReadable())
+                vm.runProgram(withExt.readText())
+            else
+                throw NoSuchFileException(withExt.toFile(), reason="not a .p8ir file")
+        }
+    }
+
+    override fun isIOAddress(address: UInt): Boolean = false
+
+    override fun initializeMemoryAreas(compilerOptions: CompilationOptions) {
+        zeropage = VirtualZeropage(compilerOptions)
+    }
+}
+
+interface IVirtualMachineRunner {
+    fun runProgram(irSource: String)
+}
+
+private class VirtualZeropage(options: CompilationOptions): Zeropage(options) {
+    override val SCRATCH_B1: UInt
+        get() = throw IllegalStateException("virtual shouldn't use this zeropage variable")
+    override val SCRATCH_REG: UInt
+        get() = throw IllegalStateException("virtual shouldn't use this zeropage variable")
+    override val SCRATCH_W1: UInt
+        get() = throw IllegalStateException("virtual shouldn't use this zeropage variable")
+    override val SCRATCH_W2: UInt
+        get() = throw IllegalStateException("virtual shouldn't use this zeropage variable")
+
+    override fun allocateCx16VirtualRegisters() { /* there is no actual zero page in this target to allocate thing in */ }
+}
@@ -0,0 +1,63 @@
+
+plugins {
+    id 'java'
+    id 'application'
+    id "org.jetbrains.kotlin.jvm"
+    id "io.kotest" version "0.3.9"
+}
+
+java {
+    toolchain {
+        languageVersion = JavaLanguageVersion.of(javaVersion)
+    }
+}
+
+compileKotlin {
+    kotlinOptions {
+        jvmTarget = javaVersion
+    }
+}
+
+compileTestKotlin {
+    kotlinOptions {
+        jvmTarget = javaVersion
+    }
+}
+
+dependencies {
+    implementation project(':codeCore')
+    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8"
+    // implementation "org.jetbrains.kotlin:kotlin-reflect"
+    implementation "com.michael-bull.kotlin-result:kotlin-result-jvm:1.1.18"
+
+    testImplementation 'io.kotest:kotest-runner-junit5-jvm:5.7.2'
+}
+
+sourceSets {
+    main {
+        java {
+            srcDir "${project.projectDir}/src"
+        }
+        resources {
+            srcDir "${project.projectDir}/res"
+        }
+    }
+    test {
+        java {
+            srcDir "${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"
+    }
+}
@@ -0,0 +1,18 @@
+<?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="library" name="michael.bull.kotlin.result.jvm" level="project" />
+    <orderEntry type="library" name="io.kotest.assertions.core.jvm" level="project" />
+    <orderEntry type="library" name="io.kotest.runner.junit5.jvm" level="project" />
+  </component>
+</module>
@@ -0,0 +1,541 @@
+package prog8.codegen.cpu6502
+
+import prog8.code.StConstant
+import prog8.code.StMemVar
+import prog8.code.SymbolTable
+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, symbolTable: SymbolTable): Int {
+
+    var numberOfOptimizations = 0
+
+    var linesByFour = getLinesBy(lines, 4)
+
+    var mods = optimizeIncDec(linesByFour)
+    if(mods.isNotEmpty()) {
+        apply(mods, lines)
+        linesByFour = getLinesBy(lines, 4)
+        numberOfOptimizations++
+    }
+
+    mods = optimizeStoreLoadSame(linesByFour, machine, symbolTable)
+    if(mods.isNotEmpty()) {
+        apply(mods, lines)
+        linesByFour = getLinesBy(lines, 4)
+        numberOfOptimizations++
+    }
+
+    mods = optimizeJsrRtsAndOtherCombinations(linesByFour)
+    if(mods.isNotEmpty()) {
+        apply(mods, lines)
+        linesByFour = getLinesBy(lines, 4)
+        numberOfOptimizations++
+    }
+
+    mods = optimizeUselessPushPopStack(linesByFour)
+    if(mods.isNotEmpty()) {
+        apply(mods, lines)
+        linesByFour = getLinesBy(lines, 4)
+        numberOfOptimizations++
+    }
+
+    mods = optimizeUnneededTempvarInAdd(linesByFour)
+    if(mods.isNotEmpty()) {
+        apply(mods, lines)
+        linesByFour = getLinesBy(lines, 4)
+        numberOfOptimizations++
+    }
+
+    var linesByFourteen = getLinesBy(lines, 14)
+    mods = optimizeSameAssignments(linesByFourteen, machine, symbolTable)
+    if(mods.isNotEmpty()) {
+        apply(mods, lines)
+        linesByFourteen = getLinesBy(lines, 14)
+        numberOfOptimizations++
+    }
+
+    mods = optimizeSamePointerIndexing(linesByFourteen)
+    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 optimizeSameAssignments(
+    linesByFourteen: List<List<IndexedValue<String>>>,
+    machine: IMachineDefinition,
+    symbolTable: SymbolTable
+): 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, symbolTable)
+                val address2 = getAddressArg(second, symbolTable)
+                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, symbolTable)
+                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, symbolTable)
+                    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, symbolTable)
+                    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, symbolTable)
+                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
+        However, this cannot be done relyably because 'A' could be a constant symbol referring to an I/O address.
+        We can't see that here and would otherwise delete valid double stores.
+        */
+    }
+
+    return mods
+}
+
+private fun optimizeSamePointerIndexing(linesByFourteen: List<List<IndexedValue<String>>>): 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,
+    symbolTable: SymbolTable
+): 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, symbolTable)
+                    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_\.$]*)""")
+
+private fun getAddressArg(line: String, symbolTable: SymbolTable): UInt? {
+    // try to get the constant value address, could return null if it's a symbol instead
+    val loadArg = line.trimStart().substring(3).trim()
+    return when {
+        loadArg.startsWith('$') -> 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
+                when (val symbol = symbolTable.flat[identifier]) {
+                    is StConstant -> symbol.value.toUInt()
+                    is StMemVar -> symbol.address
+                    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 optimizeJsrRtsAndOtherCombinations(linesByFour: List<List<IndexedValue<String>>>): List<Modification> {
+    // jsr Sub + rts -> jmp Sub
+    // rts + jmp -> remove jmp
+    // rts + bxx -> remove bxx
+
+    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)
+        }
+        else if (" rts" in first || "\trts" in first) {
+            if (" jmp" in second || "\tjmp" in second)
+                mods += Modification(lines[1].index, true, null)
+            else if (" bra" in second || "\tbra" in second)
+                mods += Modification(lines[1].index, true, null)
+            else if (" bcc" in second || "\tbcc" in second)
+                mods += Modification(lines[1].index, true, null)
+            else if (" bcs" in second || "\tbcs" in second)
+                mods += Modification(lines[1].index, true, null)
+            else if (" beq" in second || "\tbeq" in second)
+                mods += Modification(lines[1].index, true, null)
+            else if (" bne" in second || "\tbne" in second)
+                mods += Modification(lines[1].index, true, null)
+            else if (" bmi" in second || "\tbmi" in second)
+                mods += Modification(lines[1].index, true, null)
+            else if (" bpl" in second || "\tbpl" in second)
+                mods += Modification(lines[1].index, true, null)
+            else if (" bvs" in second || "\tbvs" in second)
+                mods += Modification(lines[1].index, true, null)
+            else if (" bvc" in second || "\tbvc" in second)
+                mods += Modification(lines[1].index, true, null)
+        }
+    }
+    return mods
+}
+
+private fun optimizeUselessPushPopStack(linesByFour: List<List<IndexedValue<String>>>): List<Modification> {
+    val mods = mutableListOf<Modification>()
+
+    fun optimize(register: Char, lines: List<IndexedValue<String>>) {
+        if(lines[0].value.trimStart().startsWith("ph$register")) {
+            if(lines[2].value.trimStart().startsWith("pl$register")) {
+                val second = lines[1].value.trimStart().take(6).lowercase()
+                if(register!in second
+                    && !second.startsWith("jsr")
+                    && !second.startsWith("pl")
+                    && !second.startsWith("ph")) {
+                    mods.add(Modification(lines[0].index, true, null))
+                    mods.add(Modification(lines[2].index, true, null))
+                }
+            }
+            else if (lines[3].value.trimStart().startsWith("pl$register")) {
+                val second = lines[1].value.trimStart().take(6).lowercase()
+                val third = lines[2].value.trimStart().take(6).lowercase()
+                if(register !in second && register !in third
+                    && !second.startsWith("jsr") && !third.startsWith("jsr")
+                    && !second.startsWith("pl") && !third.startsWith("pl")
+                    && !second.startsWith("ph") && !third.startsWith("ph")) {
+                    mods.add(Modification(lines[0].index, true, null))
+                    mods.add(Modification(lines[3].index, true, null))
+                }
+            }
+        }
+    }
+
+    for (lines in linesByFour) {
+        optimize('a', lines)
+        optimize('x', lines)
+        optimize('y', lines)
+    }
+    return mods
+}
+
+private fun optimizeUnneededTempvarInAdd(linesByFour: List<List<IndexedValue<String>>>): List<Modification> {
+    // sequence:  sta  P8ZP_SCRATCH_XX  / lda  something / clc / adc  P8ZP_SCRATCH_XX
+    // this can be performed without the scratch variable:  clc  /  adc  something
+    val mods = mutableListOf<Modification>()
+
+    for(lines in linesByFour) {
+        val first = lines[0].value.trimStart()
+        val second = lines[1].value.trimStart()
+        val third = lines[2].value.trimStart()
+        val fourth = lines[3].value.trimStart()
+        if(first.startsWith("sta  P8ZP_SCRATCH_") && second.startsWith("lda") && third.startsWith("clc") && fourth.startsWith("adc  P8ZP_SCRATCH_") ) {
+            if(fourth.substring(4)==first.substring(4)) {
+                mods.add(Modification(lines[0].index, false, "    clc"))
+                mods.add(Modification(lines[1].index, false, "    adc  ${second.substring(3).trimStart()}"))
+                mods.add(Modification(lines[2].index, true, null))
+                mods.add(Modification(lines[3].index, true, null))
+            }
+        }
+    }
+
+    return mods
+}
@@ -0,0 +1,28 @@
+package prog8.codegen.cpu6502
+
+import prog8.code.ast.PtAsmSub
+import prog8.code.core.Cx16VirtualRegisters
+import prog8.code.core.RegisterOrPair
+
+
+fun asmsub6502ArgsEvalOrder(sub: PtAsmSub): List<Int> {
+    val order = mutableListOf<Int>()
+    // order is:
+    //  1) cx16 virtual word registers,
+    //  2) paired CPU registers,
+    //  3) single CPU registers (order Y,X,A),
+    //  4) CPU Carry status flag
+    val args = sub.parameters.withIndex()
+    val (cx16regs, args2) = args.partition { it.value.first.registerOrPair in Cx16VirtualRegisters }
+    val pairedRegisters = arrayOf(RegisterOrPair.AX, RegisterOrPair.AY, RegisterOrPair.XY)
+    val (pairedRegs , args3) = args2.partition { it.value.first.registerOrPair in pairedRegisters }
+    val (singleRegs, rest) = args3.partition { it.value.first.registerOrPair != null }
+
+    cx16regs.forEach { order += it.index }
+    pairedRegs.forEach { order += it.index }
+    singleRegs.sortedBy { it.value.first.registerOrPair!!.asCpuRegister() }.asReversed().forEach { order += it.index }
+    require(rest.all { it.value.first.registerOrPair==null && it.value.first.statusflag!=null})
+    rest.forEach { order += it.index }
+    require(order.size==sub.parameters.size)
+    return order
+}
@@ -0,0 +1,136 @@
+package prog8.codegen.cpu6502
+
+import prog8.code.core.*
+import prog8.code.target.C64Target
+import java.nio.file.Path
+
+
+internal class AssemblyProgram(
+        override val name: String,
+        outputDir: Path,
+        private val compTarget: ICompilationTarget) : IAssemblyProgram {
+
+    private val assemblyFile = outputDir.resolve("$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("$name.bin")
+    private val viceMonListFile = outputDir.resolve(C64Target.viceMonListName(name))
+    private val listFile = outputDir.resolve("$name.list")
+
+    override fun assemble(options: CompilationOptions, errors: IErrorReporter): Boolean {
+
+        val assemblerCommand: List<String>
+
+        when (compTarget.name) {
+            in setOf("c64", "c128", "cx16", "pet32") -> {
+                // 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", "-Werror",
+                    "--dump-labels", "--vice-labels", "--labels=$viceMonListFile", "--no-monitor"
+                )
+
+                if(options.warnSymbolShadowing)
+                    command.add("-Wshadow")
+                else
+                    command.add("-Wno-shadow")
+
+                if(options.asmQuiet)
+                    command.add("--quiet")
+
+                if(options.asmListfile)
+                    command.add("--list=$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 ${compTarget.name}.")
+                        binFile
+                    }
+                    else -> throw AssemblyError("invalid output type")
+                }
+                command.addAll(listOf("--output", outFile.toString(), assemblyFile.toString()))
+                assemblerCommand = command
+
+            }
+            "atari" -> {
+                // Atari800XL .xex generation.
+
+                // TODO are these options okay for atari?
+                val command = mutableListOf("64tass", "--ascii", "--case-sensitive", "--long-branch",
+                    "-Wall", // "-Werror", "-Wno-strict-bool"
+                    "--no-monitor"
+                )
+
+                if(options.warnSymbolShadowing)
+                    command.add("-Wshadow")
+                else
+                    command.add("-Wno-shadow")
+
+                if(options.asmQuiet)
+                    command.add("--quiet")
+
+                if(options.asmListfile)
+                    command.add("--list=$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+prog8_label_.+?""")
+        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, "; breakpoint list now follows")
+        breakpoints.add(1, "; $num breakpoints have been defined")
+        breakpoints.add(2, "del")
+        viceMonListFile.toFile().appendText(breakpoints.joinToString("\n") + "\n")
+    }
+}
@@ -0,0 +1,40 @@
+package prog8.codegen.cpu6502
+
+import prog8.code.ast.IPtSubroutine
+import prog8.code.ast.PtAsmSub
+import prog8.code.ast.PtSub
+import prog8.code.core.*
+
+
+internal fun IPtSubroutine.returnsWhatWhere(): List<Pair<RegisterOrStatusflag, DataType>> {
+    when(this) {
+        is PtAsmSub -> {
+            return returns
+        }
+        is PtSub -> {
+            // for non-asm subroutines, determine the return registers based on the type of the return value
+            return if(returntype==null)
+                emptyList()
+            else {
+                val register = when (returntype!!) {
+                    in ByteDatatypes -> RegisterOrStatusflag(RegisterOrPair.A, null)
+                    in WordDatatypes -> RegisterOrStatusflag(RegisterOrPair.AY, null)
+                    DataType.FLOAT -> RegisterOrStatusflag(RegisterOrPair.FAC1, null)
+                    else -> RegisterOrStatusflag(RegisterOrPair.AY, null)
+                }
+                listOf(Pair(register, returntype!!))
+            }
+        }
+    }
+}
+
+
+internal fun PtSub.returnRegister(): RegisterOrStatusflag? {
+    return when(returntype) {
+        in ByteDatatypes -> RegisterOrStatusflag(RegisterOrPair.A, null)
+        in WordDatatypes -> RegisterOrStatusflag(RegisterOrPair.AY, null)
+        DataType.FLOAT -> RegisterOrStatusflag(RegisterOrPair.FAC1, null)
+        null -> null
+        else -> RegisterOrStatusflag(RegisterOrPair.AY, null)
+    }
+}
@@ -0,0 +1,729 @@
+package prog8.codegen.cpu6502
+
+import com.github.michaelbull.result.fold
+import prog8.code.ast.*
+import prog8.code.core.*
+import kotlin.math.absoluteValue
+
+internal class ForLoopsAsmGen(
+    private val asmgen: AsmGen6502Internal,
+    private val zeropage: Zeropage
+) {
+
+    internal fun translate(stmt: PtForLoop) {
+        val iterableDt = stmt.iterable.type
+        when(stmt.iterable) {
+            is PtRange -> {
+                val range = (stmt.iterable as PtRange).toConstantIntegerRange()
+                if(range==null) {
+                    translateForOverNonconstRange(stmt, iterableDt, stmt.iterable as PtRange)
+                } else {
+                    translateForOverConstRange(stmt, iterableDt, range)
+                }
+            }
+            is PtIdentifier -> {
+                translateForOverIterableVar(stmt, iterableDt, stmt.iterable as PtIdentifier)
+            }
+            else -> throw AssemblyError("can't iterate over ${stmt.iterable.javaClass} - should have been replaced by a variable")
+        }
+    }
+
+    private fun translateForOverNonconstRange(stmt: PtForLoop, iterableDt: DataType, range: PtRange) {
+        val loopLabel = asmgen.makeLabel("for_loop")
+        val endLabel = asmgen.makeLabel("for_end")
+        val modifiedLabel = asmgen.makeLabel("for_modified")
+        val modifiedLabel2 = asmgen.makeLabel("for_modifiedb")
+        asmgen.loopEndLabels.push(endLabel)
+        val stepsize=range.step.asConstInteger()!!
+
+        if(stepsize < -1) {
+            val limit = range.to.asConstInteger()
+            if(limit==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) {
+
+                    // bytes array, step 1 or -1
+
+                    val incdec = if(stepsize==1) "inc" else "dec"
+                    // loop over byte range via loopvar
+                    val varname = asmgen.asmVariableName(stmt.variable)
+                    asmgen.assignExpressionToVariable(range.from, varname, ArrayToElementTypes.getValue(iterableDt))
+                    asmgen.assignExpressionToRegister(range.to, RegisterOrPair.A, false)
+                    // pre-check for end already reached
+                    if(iterableDt==DataType.ARRAY_B) {
+                        asmgen.out("  sta  $modifiedLabel+1")
+                        if(stepsize<0)
+                            asmgen.out("""
+                                clc
+                                sbc  $varname
+                                bvc  +
+                                eor  #${'$'}80
+                               bpl  $endLabel""")
+                        else
+                            asmgen.out("""
+                                sec
+                                sbc  $varname
+                                bvc  +
+                                eor  #${'$'}80
+                               bmi  $endLabel""")
+                    } else {
+                        if(stepsize<0)
+                            asmgen.out("""
+                                cmp  $varname
+                                beq  +
+                                bcs  $endLabel
+""")
+                        else
+                            asmgen.out("  cmp  $varname  |  bcc  $endLabel")
+                        asmgen.out("  sta  $modifiedLabel+1")
+                    }
+                    asmgen.out(loopLabel)
+                    asmgen.translate(stmt.statements)
+                    asmgen.out("""
+                        lda  $varname
+$modifiedLabel          cmp  #0         ; modified 
+                        beq  $endLabel
+                        $incdec  $varname""")
+                    asmgen.jmp(loopLabel)
+                    asmgen.out(endLabel)
+
+                } else {
+
+                    // bytes, step >= 2 or <= -2
+
+                    // loop over byte range via loopvar
+                    val varname = asmgen.asmVariableName(stmt.variable)
+                    asmgen.assignExpressionToVariable(range.from, varname, ArrayToElementTypes.getValue(iterableDt))
+                    asmgen.assignExpressionToRegister(range.to, RegisterOrPair.A, false)
+                    // pre-check for end already reached
+                    if(iterableDt==DataType.ARRAY_B) {
+                        asmgen.out("  sta  $modifiedLabel+1")
+                        if(stepsize<0)
+                            asmgen.out("""
+                                clc
+                                sbc  $varname
+                                bvc  +
+                                eor  #${'$'}80
+                               bpl  $endLabel""")
+                        else
+                            asmgen.out("""
+                                sec
+                                sbc  $varname
+                                bvc  +
+                                eor  #${'$'}80
+                               bmi  $endLabel""")
+                    } else {
+                        if(stepsize<0)
+                            asmgen.out("""
+                                cmp  $varname
+                                beq  +
+                                bcs  $endLabel
+""")
+                        else
+                            asmgen.out("  cmp  $varname  |  bcc  $endLabel")
+                        asmgen.out("  sta  $modifiedLabel+1")
+                    }
+                    asmgen.out(loopLabel)
+                    asmgen.translate(stmt.statements)
+                    if(stepsize>0) {
+                        asmgen.out("""
+                            lda  $varname
+                            clc
+                            adc  #$stepsize
+                            sta  $varname
+$modifiedLabel              cmp  #0    ; modified
+                            bmi  $loopLabel
+                            beq  $loopLabel""")
+                    } else {
+                        asmgen.out("""
+                            lda  $varname
+                            sec
+                            sbc  #${stepsize.absoluteValue}
+                            sta  $varname
+$modifiedLabel              cmp  #0     ; modified
+                            bpl  $loopLabel""")
+                    }
+                    asmgen.out(endLabel)
+                }
+            }
+            DataType.ARRAY_W, DataType.ARRAY_UW -> {
+                when {
+
+                    // words, step 1 or -1
+
+                    stepsize == 1 || stepsize == -1 -> {
+                        val varname = asmgen.asmVariableName(stmt.variable)
+                        assignLoopvarWord(stmt, range)
+                        asmgen.assignExpressionToRegister(range.to, RegisterOrPair.AY)
+                        precheckFromToWord(iterableDt, stepsize, varname, endLabel)
+                        asmgen.out("""
+                            sty  $modifiedLabel+1
+                            sta  $modifiedLabel2+1
+$loopLabel""")
+                        asmgen.translate(stmt.statements)
+                        asmgen.out("""
+                lda  $varname+1
+$modifiedLabel  cmp  #0    ; modified 
+                bne  +
+                lda  $varname
+$modifiedLabel2 cmp  #0    ; modified 
+                beq  $endLabel""")
+                        if(stepsize==1) {
+                            asmgen.out("""
+               inc  $varname
+                bne  $loopLabel
+                inc  $varname+1""")
+                            asmgen.jmp(loopLabel)
+                        } else {
+                            asmgen.out("""
+               lda  $varname
+                bne  +
+                dec  $varname+1
+               dec  $varname""")
+                            asmgen.jmp(loopLabel)
+                        }
+                        asmgen.out(endLabel)
+                    }
+                    stepsize > 0 -> {
+
+                        // (u)words, step >= 2
+                        val varname = asmgen.asmVariableName(stmt.variable)
+                        assignLoopvarWord(stmt, range)
+                        asmgen.assignExpressionToRegister(range.to, RegisterOrPair.AY)
+                        precheckFromToWord(iterableDt, stepsize, varname, endLabel)
+                        asmgen.out("""
+                            sty  $modifiedLabel+1
+                            sta  $modifiedLabel2+1
+$loopLabel""")
+                        asmgen.translate(stmt.statements)
+
+                        if (iterableDt == DataType.ARRAY_UW) {
+                            asmgen.out("""
+                lda  $varname
+                clc
+                adc  #<$stepsize
+                sta  $varname
+                lda  $varname+1
+                adc  #>$stepsize
+                sta  $varname+1
+$modifiedLabel  cmp  #0     ; modified
+                bcc  $loopLabel
+                bne  $endLabel
+$modifiedLabel2 lda  #0     ; modified
+                cmp  $varname
+                bcc  $endLabel
+                bcs  $loopLabel
+$endLabel""")
+                        } else {
+                            asmgen.out("""
+                lda  $varname
+                clc
+                adc  #<$stepsize
+                sta  $varname
+                lda  $varname+1
+                adc  #>$stepsize
+                sta  $varname+1
+$modifiedLabel2 lda  #0   ; modified
+                cmp  $varname
+$modifiedLabel  lda  #0   ; modified
+                sbc  $varname+1
+                bvc  +
+                eor  #$80
+               bpl  $loopLabel                
+$endLabel""")
+                        }
+                    }
+                    else -> {
+
+                        // (u)words, step <= -2
+                        val varname = asmgen.asmVariableName(stmt.variable)
+                        assignLoopvarWord(stmt, range)
+                        asmgen.assignExpressionToRegister(range.to, RegisterOrPair.AY)
+                        precheckFromToWord(iterableDt, stepsize, varname, endLabel)
+                        asmgen.out("""
+                            sty  $modifiedLabel+1
+                            sta  $modifiedLabel2+1
+$loopLabel""")
+                        asmgen.translate(stmt.statements)
+
+                            asmgen.out("""
+                lda  $varname
+                sec
+                sbc  #<${stepsize.absoluteValue}
+                sta  $varname
+                tax
+                lda  $varname+1
+                sbc  #>${stepsize.absoluteValue}
+                sta  $varname+1
+                txa
+$modifiedLabel2 cmp  #0    ; modified 
+                lda  $varname+1
+$modifiedLabel  sbc  #0    ; modified
+                bvc  +
+                eor  #$80
+               bpl  $loopLabel                
+$endLabel""")
+                    }
+                }
+            }
+            else -> throw AssemblyError("range expression can only be byte or word")
+        }
+
+        asmgen.loopEndLabels.pop()
+    }
+
+    private fun precheckFromToWord(iterableDt: DataType, stepsize: Int, fromVar: String, endLabel: String) {
+        // pre-check for end already reached.
+        // 'to' is in AY, do NOT clobber this!
+        if(iterableDt==DataType.ARRAY_W) {
+            if(stepsize<0)
+                asmgen.out("""
+                    sta  P8ZP_SCRATCH_W2        ; to
+                    sty  P8ZP_SCRATCH_W2+1      ; to
+                    lda  $fromVar
+	                cmp  P8ZP_SCRATCH_W2
+                    lda  $fromVar+1
+	                sbc  P8ZP_SCRATCH_W2+1
+	                bvc  +
+	                eor  #${'$'}80
+           		bmi  $endLabel
+                    lda  P8ZP_SCRATCH_W2
+                    ldy  P8ZP_SCRATCH_W2+1""")
+            else
+                asmgen.out("""
+                    sta  P8ZP_SCRATCH_REG
+	                cmp  $fromVar
+	                tya
+	                sbc  $fromVar+1
+	                bvc  +
+	                eor  #${'$'}80
+           		bmi  $endLabel
+                    lda  P8ZP_SCRATCH_REG""")
+        } else {
+            if(stepsize<0)
+                asmgen.out("""
+                    cpy  $fromVar+1
+                    beq  +
+                    bcc  ++
+                    bcs  $endLabel
+                   cmp  $fromVar
+                    bcc  +
+                    beq  +
+                    bne  $endLabel
+""")
+            else
+                asmgen.out("""
+                	cpy  $fromVar+1
+	                bcc  $endLabel
+	                bne  +
+	                cmp  $fromVar
+	                bcc  $endLabel
+""")
+        }
+    }
+
+    private fun translateForOverIterableVar(stmt: PtForLoop, iterableDt: DataType, ident: PtIdentifier) {
+        val loopLabel = asmgen.makeLabel("for_loop")
+        val endLabel = asmgen.makeLabel("for_end")
+        asmgen.loopEndLabels.push(endLabel)
+        val iterableName = asmgen.asmVariableName(ident)
+        val symbol = asmgen.symbolTable.lookup(ident.name)
+        val decl = symbol!!.astNode as IPtVariable
+        val numElements = when(decl) {
+            is PtConstant -> throw AssemblyError("length of non-array requested")
+            is PtMemMapped -> decl.arraySize
+            is PtVariable -> decl.arraySize
+        }
+        when(iterableDt) {
+            DataType.STR -> {
+                asmgen.out("""
+                    lda  #<$iterableName
+                    ldy  #>$iterableName
+                    sta  $loopLabel+1
+                    sty  $loopLabel+2
+$loopLabel          lda  ${65535.toHex()}       ; modified
+                    beq  $endLabel
+                    sta  ${asmgen.asmVariableName(stmt.variable)}""")
+                asmgen.translate(stmt.statements)
+                asmgen.out("""
+                    inc  $loopLabel+1
+                    bne  $loopLabel
+                    inc  $loopLabel+2
+                    bne  $loopLabel
+$endLabel""")
+            }
+            DataType.ARRAY_UB, DataType.ARRAY_B -> {
+                val indexVar = asmgen.makeLabel("for_index")
+                asmgen.out("""
+                    ldy  #0
+$loopLabel          sty  $indexVar
+                    lda  $iterableName,y
+                    sta  ${asmgen.asmVariableName(stmt.variable)}""")
+                asmgen.translate(stmt.statements)
+                if(numElements!!<=255u) {
+                    asmgen.out("""
+                        ldy  $indexVar
+                        iny
+                        cpy  #$numElements
+                        beq  $endLabel
+                        bne  $loopLabel""")
+                } else {
+                    // length is 256
+                    asmgen.out("""
+                        ldy  $indexVar
+                        iny
+                        bne  $loopLabel
+                        beq  $endLabel""")
+                }
+                if(numElements>=16u) {
+                    // allocate index var on ZP if possible
+                    val result = zeropage.allocate(indexVar, DataType.UBYTE, null, stmt.position, asmgen.errors)
+                    result.fold(
+                        success = { (address, _, _)-> asmgen.out("""$indexVar = $address  ; auto zp UBYTE""") },
+                        failure = { asmgen.out("$indexVar    .byte  0") }
+                    )
+                } else {
+                    asmgen.out("$indexVar    .byte  0")
+                }
+                asmgen.out(endLabel)
+            }
+            DataType.ARRAY_W, DataType.ARRAY_UW -> {
+                val length = numElements!! * 2u
+                val indexVar = asmgen.makeLabel("for_index")
+                val loopvarName = asmgen.asmVariableName(stmt.variable)
+                asmgen.out("""
+                    ldy  #0
+$loopLabel          sty  $indexVar
+                    lda  $iterableName,y
+                    sta  $loopvarName
+                    lda  $iterableName+1,y
+                    sta  $loopvarName+1""")
+                asmgen.translate(stmt.statements)
+                if(length<=127u) {
+                    asmgen.out("""
+                        ldy  $indexVar
+                        iny
+                        iny
+                        cpy  #$length
+                        beq  $endLabel
+                        bne  $loopLabel""")
+                } else {
+                    // length is 128 words, 256 bytes
+                    asmgen.out("""
+                        ldy  $indexVar
+                        iny
+                        iny
+                        bne  $loopLabel
+                        beq  $endLabel""")
+                }
+                if(length>=16u) {
+                    // allocate index var on ZP if possible
+                    val result = zeropage.allocate(indexVar, DataType.UBYTE, null, stmt.position, asmgen.errors)
+                    result.fold(
+                        success = { (address,_,_)-> asmgen.out("""$indexVar = $address  ; auto zp UBYTE""") },
+                        failure = { asmgen.out("$indexVar    .byte  0") }
+                    )
+                } else {
+                    asmgen.out("$indexVar    .byte  0")
+                }
+                asmgen.out(endLabel)
+            }
+            DataType.ARRAY_UW_SPLIT, DataType.ARRAY_W_SPLIT -> {
+                numElements!!
+                val indexVar = asmgen.makeLabel("for_index")
+                val loopvarName = asmgen.asmVariableName(stmt.variable)
+                asmgen.out("""
+                    ldy  #0
+$loopLabel          sty  $indexVar
+                    lda  ${iterableName}_lsb,y
+                    sta  $loopvarName
+                    lda  ${iterableName}_msb,y
+                    sta  $loopvarName+1""")
+                asmgen.translate(stmt.statements)
+                if(numElements<=255u) {
+                    asmgen.out("""
+                        ldy  $indexVar
+                        iny
+                        cpy  #$numElements
+                        beq  $endLabel
+                        bne  $loopLabel""")
+                } else {
+                    // length is 256
+                    asmgen.out("""
+                        ldy  $indexVar
+                        iny
+                        bne  $loopLabel
+                        beq  $endLabel""")
+                }
+                if(numElements>=16u) {
+                    // allocate index var on ZP if possible
+                    val result = zeropage.allocate(indexVar, DataType.UBYTE, null, stmt.position, asmgen.errors)
+                    result.fold(
+                        success = { (address,_,_)-> asmgen.out("""$indexVar = $address  ; auto zp UBYTE""") },
+                        failure = { asmgen.out("$indexVar    .byte  0") }
+                    )
+                } else {
+                    asmgen.out("$indexVar    .byte  0")
+                }
+                asmgen.out(endLabel)
+            }
+            DataType.ARRAY_F -> {
+                throw AssemblyError("for loop with floating point variables is not supported")
+            }
+            else -> throw AssemblyError("can't iterate over $iterableDt")
+        }
+        asmgen.loopEndLabels.pop()
+    }
+
+    private fun translateForOverConstRange(stmt: PtForLoop, iterableDt: DataType, range: IntProgression) {
+        if (range.isEmpty() || range.step==0)
+            throw AssemblyError("empty range or step 0")
+        if(iterableDt==DataType.ARRAY_B || iterableDt==DataType.ARRAY_UB) {
+            if(range.step==1 && range.last>range.first) return translateForSimpleByteRangeAsc(stmt, range)
+            if(range.step==-1 && range.last<range.first) return translateForSimpleByteRangeDesc(stmt, range)
+        }
+        else if(iterableDt==DataType.ARRAY_W || iterableDt==DataType.ARRAY_UW) {
+            if(range.step==1 && range.last>range.first) return translateForSimpleWordRangeAsc(stmt, range)
+            if(range.step==-1 && range.last<range.first) return translateForSimpleWordRangeDesc(stmt, range)
+        }
+
+        // not one of the easy cases, generate more complex code...
+        val loopLabel = asmgen.makeLabel("for_loop")
+        val endLabel = asmgen.makeLabel("for_end")
+        asmgen.loopEndLabels.push(endLabel)
+        when(iterableDt) {
+            DataType.ARRAY_B, DataType.ARRAY_UB -> {
+                // loop over byte range via loopvar, step >= 2 or <= -2
+                val varname = asmgen.asmVariableName(stmt.variable)
+                asmgen.out("""
+                            lda  #${range.first}
+                            sta  $varname
+$loopLabel""")
+                asmgen.translate(stmt.statements)
+                when (range.step) {
+                    0, 1, -1 -> {
+                        throw AssemblyError("step 0, 1 and -1 should have been handled specifically  $stmt")
+                    }
+                    2 -> {
+                        if(range.last==255 || range.last==254) {
+                            asmgen.out("""
+                                inc  $varname
+                                beq  $endLabel
+                                inc  $varname
+                                bne  $loopLabel""")
+                        } else {
+                            asmgen.out("""
+                                inc  $varname
+                                inc  $varname
+                                lda  $varname
+                                cmp  #${range.last+2}
+                                bne  $loopLabel""")
+                        }
+                    }
+                    -2 -> {
+                        when (range.last) {
+                            0 -> {
+                                asmgen.out("""
+                                    lda  $varname
+                                    beq  $endLabel
+                                    dec  $varname
+                                    dec  $varname""")
+                                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-2}
+                                    bne  $loopLabel""")
+                        }
+                    }
+                    else -> {
+                        // step <= -3 or >= 3
+                        asmgen.out("""
+                            lda  $varname
+                            cmp  #${range.last}
+                            beq  $endLabel
+                            clc
+                            adc  #${range.step}
+                            sta  $varname""")
+                        asmgen.jmp(loopLabel)
+                    }
+                }
+                asmgen.out(endLabel)
+            }
+            DataType.ARRAY_W, DataType.ARRAY_UW -> {
+                // loop over word range via loopvar, step >= 2 or <= -2
+                val varname = asmgen.asmVariableName(stmt.variable)
+                when (range.step) {
+                    0, 1, -1 -> {
+                        throw AssemblyError("step 0, 1 and -1 should have been handled specifically  $stmt")
+                    }
+                    else -> {
+                        // word, step >= 2 or <= -2
+                        // note: range.last has already been adjusted by kotlin itself to actually be the last value of the sequence
+                        asmgen.out("""
+                            lda  #<${range.first}
+                            ldy  #>${range.first}
+                            sta  $varname
+                            sty  $varname+1
+$loopLabel""")
+                        asmgen.translate(stmt.statements)
+                        asmgen.out("""
+                            lda  $varname
+                            cmp  #<${range.last}
+                            bne  +
+                            lda  $varname+1
+                            cmp  #>${range.last}
+                            bne  +
+                            beq  $endLabel
+                           lda  $varname
+                            clc
+                            adc  #<${range.step}
+                            sta  $varname
+                            lda  $varname+1
+                            adc  #>${range.step}
+                            sta  $varname+1""")
+                        asmgen.jmp(loopLabel)
+                        asmgen.out(endLabel)
+                    }
+                }
+            }
+            else -> throw AssemblyError("range expression can only be byte or word")
+        }
+        asmgen.loopEndLabels.pop()
+    }
+
+    private fun translateForSimpleByteRangeAsc(stmt: PtForLoop, range: IntProgression) {
+        val loopLabel = asmgen.makeLabel("for_loop")
+        val endLabel = asmgen.makeLabel("for_end")
+        asmgen.loopEndLabels.push(endLabel)
+        val varname = asmgen.asmVariableName(stmt.variable)
+        asmgen.out("""
+                lda  #${range.first}
+                sta  $varname
+$loopLabel""")
+        asmgen.translate(stmt.statements)
+        if (range.last == 255) {
+            asmgen.out("""
+                inc  $varname
+                bne  $loopLabel
+$endLabel""")
+        } else {
+            asmgen.out("""
+                inc  $varname
+                lda  $varname
+                cmp  #${range.last+1}
+                bne  $loopLabel
+$endLabel""")
+        }
+        asmgen.loopEndLabels.pop()
+    }
+
+    private fun translateForSimpleByteRangeDesc(stmt: PtForLoop, range: IntProgression) {
+        val loopLabel = asmgen.makeLabel("for_loop")
+        val endLabel = asmgen.makeLabel("for_end")
+        asmgen.loopEndLabels.push(endLabel)
+        val varname = asmgen.asmVariableName(stmt.variable)
+        asmgen.out("""
+                    lda  #${range.first}
+                    sta  $varname
+$loopLabel""")
+        asmgen.translate(stmt.statements)
+        when (range.last) {
+            0 -> {
+                asmgen.out("""
+                    lda  $varname
+                    beq  $endLabel
+                    dec  $varname""")
+                asmgen.jmp(loopLabel)
+                asmgen.out(endLabel)
+            }
+            1 -> {
+                asmgen.out("""
+                    dec  $varname
+                    bne  $loopLabel
+$endLabel""")
+            }
+            else -> {
+                asmgen.out("""
+                    dec  $varname
+                    lda  $varname
+                    cmp  #${range.last-1}
+                    bne  $loopLabel
+$endLabel""")
+            }
+        }
+        asmgen.loopEndLabels.pop()
+    }
+
+    private fun translateForSimpleWordRangeAsc(stmt: PtForLoop, range: IntProgression) {
+        val loopLabel = asmgen.makeLabel("for_loop")
+        val endLabel = asmgen.makeLabel("for_end")
+        asmgen.loopEndLabels.push(endLabel)
+        val varname = asmgen.asmVariableName(stmt.variable)
+        asmgen.out("""
+            lda  #<${range.first}
+            ldy  #>${range.first}
+            sta  $varname
+            sty  $varname+1
+$loopLabel""")
+        asmgen.translate(stmt.statements)
+        asmgen.out("""
+            lda  $varname
+            cmp  #<${range.last}
+            bne  +
+            lda  $varname+1
+            cmp  #>${range.last}
+            beq  $endLabel
+           inc  $varname
+            bne  $loopLabel
+            inc  $varname+1""")
+        asmgen.jmp(loopLabel)
+        asmgen.out(endLabel)
+        asmgen.loopEndLabels.pop()
+    }
+
+    private fun translateForSimpleWordRangeDesc(stmt: PtForLoop, range: IntProgression) {
+        val loopLabel = asmgen.makeLabel("for_loop")
+        val endLabel = asmgen.makeLabel("for_end")
+        asmgen.loopEndLabels.push(endLabel)
+        val varname = asmgen.asmVariableName(stmt.variable)
+        asmgen.out("""
+            lda  #<${range.first}
+            ldy  #>${range.first}
+            sta  $varname
+            sty  $varname+1
+$loopLabel""")
+        asmgen.translate(stmt.statements)
+        asmgen.out("""
+            lda  $varname
+            cmp  #<${range.last}
+            bne  +
+            lda  $varname+1
+            cmp  #>${range.last}
+            beq  $endLabel
+           lda  $varname
+            bne  +
+            dec  $varname+1
+           dec  $varname""")
+        asmgen.jmp(loopLabel)
+        asmgen.out(endLabel)
+        asmgen.loopEndLabels.pop()
+    }
+
+    private fun assignLoopvarWord(stmt: PtForLoop, range: PtRange) =
+        asmgen.assignExpressionToVariable(
+            range.from,
+            asmgen.asmVariableName(stmt.variable),
+            stmt.variable.type)
+}
@@ -0,0 +1,237 @@
+package prog8.codegen.cpu6502
+
+import prog8.code.ast.*
+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: PtProgram, private val asmgen: AsmGen6502Internal) {
+
+    internal fun translateFunctionCallStatement(stmt: PtFunctionCall) {
+        translateFunctionCall(stmt)
+        // just ignore any result values from the function call.
+    }
+
+    internal fun optimizeIntArgsViaRegisters(sub: PtSub) =
+        (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: PtFunctionCall) {
+        // 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 symbol = asmgen.symbolTable.lookup(call.name)
+        val sub = symbol!!.astNode as IPtSubroutine
+        val subAsmName = asmgen.asmSymbolName(call.name)
+
+        if(sub is PtAsmSub) {
+            argumentsViaRegisters(sub, call)
+            if (sub.inline) {
+                // inline the subroutine. (regardless of optimization settings!)
+                // 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.children.forEach { asmgen.translate(it as PtInlineAssembly) }
+                asmgen.out("  \t; inlined routine end: ${sub.name}")
+            } else {
+                asmgen.out("  jsr  $subAsmName")
+            }
+        }
+        else if(sub is PtSub) {
+            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")
+        }
+        else throw AssemblyError("invalid sub type")
+
+        // remember: dealing with the X register and/or dealing with return values is the responsibility of the caller
+    }
+
+
+    private fun usesOtherRegistersWhileEvaluating(arg: PtExpression): Boolean {
+        return when(arg) {
+            is PtBuiltinFunctionCall -> {
+                if (arg.name == "lsb" || arg.name == "msb")
+                    return usesOtherRegistersWhileEvaluating(arg.args[0])
+                if (arg.name == "mkword")
+                    return usesOtherRegistersWhileEvaluating(arg.args[0]) || usesOtherRegistersWhileEvaluating(arg.args[1])
+                return !arg.isSimple()
+            }
+            is PtAddressOf -> false
+            is PtIdentifier -> false
+            is PtMachineRegister -> false
+            is PtMemoryByte -> false
+            is PtNumber -> false
+            else -> true
+        }
+    }
+
+    private fun argumentsViaRegisters(sub: PtAsmSub, call: PtFunctionCall) {
+        val registersUsed = mutableListOf<RegisterOrStatusflag>();
+
+        fun usedA() = registersUsed.any {it.registerOrPair==RegisterOrPair.A || it.registerOrPair==RegisterOrPair.AX || it.registerOrPair==RegisterOrPair.AY}
+        fun usedX() = registersUsed.any {it.registerOrPair==RegisterOrPair.X || it.registerOrPair==RegisterOrPair.AX || it.registerOrPair==RegisterOrPair.XY}
+        fun usedY() = registersUsed.any {it.registerOrPair==RegisterOrPair.Y || it.registerOrPair==RegisterOrPair.AY || it.registerOrPair==RegisterOrPair.XY}
+
+        if(sub.parameters.size==1) {
+            argumentViaRegister(sub, IndexedValue(0, sub.parameters.single().second), call.args[0])
+        } else {
+            val optimalEvalOrder = asmsub6502ArgsEvalOrder(sub)
+            optimalEvalOrder.forEach {
+                val param = sub.parameters[it]
+                val arg = call.args[it]
+                registersUsed += if(usesOtherRegistersWhileEvaluating(arg)) {
+                    if(!registersUsed.any{it.statusflag!=null || it.registerOrPair in CpuRegisters})
+                        argumentViaRegister(sub, IndexedValue(it, param.second), arg)
+                    else if(registersUsed.any {it.statusflag!=null}) {
+                        throw AssemblyError("call argument evaluation problem: can't save cpu statusregister parameter ${call.position}")
+                    }
+                    else {
+                        if(usedX()) asmgen.saveRegisterStack(CpuRegister.X, false)
+                        if(usedY()) asmgen.saveRegisterStack(CpuRegister.Y, false)
+                        if(usedA()) asmgen.saveRegisterStack(CpuRegister.A, false)
+                        val used = argumentViaRegister(sub, IndexedValue(it, param.second), arg)
+                        if(usedA()) asmgen.restoreRegisterStack(CpuRegister.A, false)
+                        if(usedY()) asmgen.restoreRegisterStack(CpuRegister.Y, true)
+                        if(usedX()) asmgen.restoreRegisterStack(CpuRegister.X, true)
+                        used
+                    }
+                } else {
+                    argumentViaRegister(sub, IndexedValue(it, param.second), arg)
+                }
+            }
+        }
+    }
+
+    private fun argumentViaVariable(sub: PtSub, parameter: PtSubroutineParameter, value: PtExpression) {
+        // pass parameter via a regular variable (not via registers)
+        if(!isArgumentTypeCompatible(value.type, parameter.type))
+            throw AssemblyError("argument type incompatible")
+
+        val varName = asmgen.asmVariableName(sub.scopedName + "." + parameter.name)
+        asmgen.assignExpressionToVariable(value, varName, parameter.type)
+    }
+
+    private fun argumentViaRegister(sub: IPtSubroutine, parameter: IndexedValue<PtSubroutineParameter>, value: PtExpression, registerOverride: RegisterOrPair? = null): RegisterOrStatusflag {
+        // pass argument via a register parameter
+        if(!isArgumentTypeCompatible(value.type, parameter.value.type))
+            throw AssemblyError("argument type incompatible")
+
+        val paramRegister: RegisterOrStatusflag = when(sub) {
+            is PtAsmSub -> if(registerOverride==null) sub.parameters[parameter.index].first else RegisterOrStatusflag(registerOverride, null)
+            is PtSub -> RegisterOrStatusflag(registerOverride!!, null)
+        }
+        val statusflag = paramRegister.statusflag
+        val register = paramRegister.registerOrPair
+        val requiredDt = parameter.value.type
+        if(requiredDt!=value.type) {
+            if(value.type largerThan requiredDt)
+                throw AssemblyError("can only convert byte values to word param types")
+        }
+        if (statusflag!=null) {
+            if(requiredDt!=value.type)
+                throw AssemblyError("for statusflag, byte value is required")
+            if (statusflag == Statusflag.Pc) {
+                // this boolean 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 PtNumber -> {
+                        val carrySet = value.number.toInt() != 0
+                        asmgen.out(if(carrySet) "  sec" else "  clc")
+                    }
+                    is PtIdentifier -> {
+                        val sourceName = asmgen.asmVariableName(value)
+                        // note: cannot use X register here to store A because it might be used for other arguments
+                        asmgen.out("""
+                            pha
+                            clc
+                            lda  $sourceName
+                            beq  +
+                            sec  
+                           pla""")
+                    }
+                    else -> {
+                        asmgen.assignExpressionToRegister(value, RegisterOrPair.A)
+                        asmgen.out("  ror  a")
+                    }
+                }
+            } else throw AssemblyError("can only use Carry as status flag parameter")
+            return RegisterOrStatusflag(null, statusflag)
+        }
+        else {
+            // via register or register pair
+            register!!
+            if(requiredDt largerThan value.type) {
+                // we need to sign extend the source, do this via temporary word variable
+                asmgen.assignExpressionToVariable(value, "P8ZP_SCRATCH_W1", DataType.UBYTE)
+                asmgen.signExtendVariableLsb("P8ZP_SCRATCH_W1", value.type)
+                asmgen.assignVariableToRegister("P8ZP_SCRATCH_W1", register, null, Position.DUMMY)
+            } else {
+                val scope = value.definingISub()
+                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, scope, value.position, register = register)
+                    else {
+                        val signed = parameter.value.type == DataType.BYTE || parameter.value.type == DataType.WORD
+                        AsmAssignTarget.fromRegisters(register, signed, value.position, scope, asmgen)
+                    }
+                val src = if(value.type in PassByReferenceDatatypes) {
+                    if(value is PtIdentifier) {
+                        val addr = PtAddressOf(Position.DUMMY)
+                        addr.add(value)
+                        addr.parent = sub as PtNode
+                        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, program.memsizer, Position.DUMMY), scope)
+            }
+            return RegisterOrStatusflag(register, null)
+        }
+    }
+
+    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
+    }
+}
+
+
@@ -0,0 +1,175 @@
+package prog8.codegen.cpu6502
+
+import prog8.code.ast.PtIdentifier
+import prog8.code.ast.PtNumber
+import prog8.code.ast.PtPostIncrDecr
+import prog8.code.ast.PtProgram
+import prog8.code.core.*
+
+
+internal class PostIncrDecrAsmGen(private val program: PtProgram, private val asmgen: AsmGen6502Internal) {
+    internal fun translate(stmt: PtPostIncrDecr) {
+        val incr = stmt.operator=="++"
+        val targetIdent = stmt.target.identifier
+        val targetMemory = stmt.target.memory
+        val targetArrayIdx = stmt.target.array
+        when {
+            targetIdent!=null -> {
+                val what = asmgen.asmVariableName(targetIdent)
+                when (stmt.target.type) {
+                    in ByteDatatypes -> asmgen.out(if (incr) "  inc  $what" else "  dec  $what")
+                    in WordDatatypes -> {
+                        if(incr)
+                            asmgen.out(" inc  $what |  bne  + |  inc  $what+1 |+")
+                        else
+                            asmgen.out("""
+        lda  $what
+        bne  +
+        dec  $what+1
+       dec  $what 
+""")
+                    }
+                    DataType.FLOAT -> {
+                        asmgen.out("  lda  #<$what |  ldy  #>$what")
+                        asmgen.out(if(incr) "  jsr  floats.inc_var_f" else "  jsr  floats.dec_var_f")
+                    }
+                    else -> throw AssemblyError("need numeric type")
+                }
+            }
+            targetMemory!=null -> {
+                when (val addressExpr = targetMemory.address) {
+                    is PtNumber -> {
+                        val what = addressExpr.number.toHex()
+                        asmgen.out(if(incr) "  inc  $what" else "  dec  $what")
+                    }
+                    is PtIdentifier -> {
+                        val what = asmgen.asmVariableName(addressExpr)
+                        asmgen.out("  lda  $what |  sta  (+) +1 |  lda  $what+1 |  sta  (+) +2")
+                        if(incr)
+                            asmgen.out("+\tinc  ${'$'}ffff\t; modified")
+                        else
+                            asmgen.out("+\tdec  ${'$'}ffff\t; modified")
+                    }
+                    else -> {
+                        asmgen.assignExpressionToRegister(addressExpr, RegisterOrPair.AY)
+                        asmgen.out("  sta  (+) + 1 |  sty  (+) + 2")
+                        if(incr)
+                            asmgen.out("+\tinc  ${'$'}ffff\t; modified")
+                        else
+                            asmgen.out("+\tdec  ${'$'}ffff\t; modified")
+                    }
+                }
+            }
+            targetArrayIdx!=null -> {
+                val asmArrayvarname = asmgen.asmVariableName(targetArrayIdx.variable)
+                val elementDt = targetArrayIdx.type
+                val constIndex = targetArrayIdx.index.asConstInteger()
+                if(targetArrayIdx.splitWords) {
+                    if(constIndex!=null) {
+                        if(incr)
+                            asmgen.out(" inc  ${asmArrayvarname}_lsb+$constIndex |  bne  + |  inc  ${asmArrayvarname}_msb+$constIndex |+")
+                        else
+                            asmgen.out("""
+        lda  ${asmArrayvarname}_lsb+$constIndex
+        bne  +
+        dec  ${asmArrayvarname}_msb+$constIndex
+       dec  ${asmArrayvarname}_lsb+$constIndex""")
+                    } else {
+                        asmgen.loadScaledArrayIndexIntoRegister(targetArrayIdx, elementDt, CpuRegister.X)
+                        if(incr)
+                            asmgen.out(" inc  ${asmArrayvarname}_lsb,x |  bne  + |  inc  ${asmArrayvarname}_msb,x |+")
+                        else
+                            asmgen.out("""
+        lda  ${asmArrayvarname}_lsb,x
+        bne  +
+        dec  ${asmArrayvarname}_msb,x
+       dec  ${asmArrayvarname}_lsb,x""")
+                    }
+                    return
+                }
+                if(constIndex!=null) {
+                    val indexValue = constIndex * program.memsizer.memorySize(elementDt)
+                    when(elementDt) {
+                        in ByteDatatypes -> {
+                            if(targetArrayIdx.usesPointerVariable) {
+                                asmgen.out("""
+                                    lda  $asmArrayvarname
+                                    clc
+                                    adc  #$indexValue
+                                    sta  (+) +1
+                                    lda  $asmArrayvarname+1
+                                    adc  #0
+                                    sta  (+) +2""")
+                                if(incr)
+                                    asmgen.out("+\tinc  ${'$'}ffff\t; modified")
+                                else
+                                    asmgen.out("+\tdec  ${'$'}ffff\t; modified")
+                            } else {
+                                asmgen.out(if (incr) "  inc  $asmArrayvarname+$indexValue" else "  dec  $asmArrayvarname+$indexValue")
+                            }
+                        }
+                        in WordDatatypes -> {
+                            if(incr)
+                                asmgen.out(" inc  $asmArrayvarname+$indexValue |  bne  + |  inc  $asmArrayvarname+$indexValue+1 |+")
+                            else
+                                asmgen.out("""
+        lda  $asmArrayvarname+$indexValue
+        bne  +
+        dec  $asmArrayvarname+$indexValue+1
+       dec  $asmArrayvarname+$indexValue""")
+                        }
+                        DataType.FLOAT -> {
+                            asmgen.out("  lda  #<($asmArrayvarname+$indexValue) |  ldy  #>($asmArrayvarname+$indexValue)")
+                            asmgen.out(if(incr) "  jsr  floats.inc_var_f" else "  jsr  floats.dec_var_f")
+                        }
+                        else -> throw AssemblyError("need numeric type")
+                    }
+                }
+                else
+                {
+                    asmgen.loadScaledArrayIndexIntoRegister(targetArrayIdx, elementDt, CpuRegister.X)
+                    when(elementDt) {
+                        in ByteDatatypes -> {
+                            if(targetArrayIdx.usesPointerVariable) {
+                                asmgen.out("""
+                                    txa
+                                    clc
+                                    adc  $asmArrayvarname
+                                    sta  (+) +1
+                                    lda  $asmArrayvarname+1
+                                    adc  #0
+                                    sta  (+) +2""")
+                                if(incr)
+                                    asmgen.out("+\tinc  ${'$'}ffff\t; modified")
+                                else
+                                    asmgen.out("+\tdec  ${'$'}ffff\t; modified")
+                            } else {
+                                asmgen.out(if (incr) "  inc  $asmArrayvarname,x" else "  dec  $asmArrayvarname,x")
+                            }
+                        }
+                        in WordDatatypes -> {
+                            if(incr)
+                                asmgen.out(" inc  $asmArrayvarname,x |  bne  + |  inc  $asmArrayvarname+1,x |+")
+                            else
+                                asmgen.out("""
+        lda  $asmArrayvarname,x
+        bne  +
+        dec  $asmArrayvarname+1,x
+       dec  $asmArrayvarname,x""")
+                        }
+                        DataType.FLOAT -> {
+                            asmgen.out("""
+        ldy  #>$asmArrayvarname
+        clc
+        adc  #<$asmArrayvarname
+        bcc  +
+        iny
+       jsr  floats.inc_var_f""")
+                        }
+                        else -> throw AssemblyError("weird array elt dt")
+                    }
+                }
+            }
+        }
+    }
+}
@@ -0,0 +1,755 @@
+package prog8.codegen.cpu6502
+
+import prog8.code.*
+import prog8.code.ast.*
+import prog8.code.core.*
+import prog8.codegen.cpu6502.assignment.AsmAssignTarget
+import prog8.codegen.cpu6502.assignment.TargetStorageKind
+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: PtProgram,
+    val options: CompilationOptions,
+    val errors: IErrorReporter,
+    private val symboltable: SymbolTable,
+    private val functioncallAsmGen: FunctionCallAsmGen,
+    private val asmgen: AsmGen6502Internal,
+    private val allocator: VariableAllocator,
+    private val zeropage: Zeropage
+) {
+    private val compTarget = options.compTarget
+    private val blockVariableInitializers = program.allBlocks().associateWith { it.children.filterIsInstance<PtAssignment>() }
+
+    internal fun generate() {
+        header()
+        val allBlocks = program.allBlocks()
+
+        if(allBlocks.first().name != "p8_main" && allBlocks.first().name != "main")
+            throw AssemblyError("first block should be 'main' or 'p8_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'")
+
+        // 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 = ${zp.SCRATCH_W2}    ; word")
+        asmgen.out(".weak")   // hack to allow user to override the following two with command line redefinition (however, just use '-esa' command line option instead!)
+        asmgen.out(".endweak")
+
+        if(options.symbolDefs.isNotEmpty()) {
+            asmgen.out("; -- user supplied symbols on the command line")
+            for((name, value) in options.symbolDefs) {
+                asmgen.out("$name = $value")
+            }
+        }
+
+        when(options.output) {
+            OutputType.RAW -> {
+                asmgen.out("; ---- raw assembler program ----")
+                asmgen.out("* = ${options.loadAddress.toHex()}")
+            }
+            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.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")
+                        if(!options.noSysInit)
+                            asmgen.out("  jsr  sys.init_system")
+                        asmgen.out("  jsr  sys.init_system_phase2")
+                    }
+                    CbmPrgLauncherType.NONE -> {
+                        asmgen.out("; ---- program without basic sys call ----")
+                        asmgen.out("* = ${options.loadAddress.toHex()}")
+                        if(!options.noSysInit)
+                            asmgen.out("  jsr  sys.init_system")
+                        asmgen.out("  jsr  sys.init_system_phase2")
+                    }
+                }
+            }
+            OutputType.XEX -> {
+                asmgen.out("; ---- atari xex program ----")
+                asmgen.out("* = ${options.loadAddress.toHex()}")
+                if(!options.noSysInit)
+                    asmgen.out("  jsr  sys.init_system")
+                asmgen.out("  jsr  sys.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  p8_main.p8_start")
+                asmgen.out("  jmp  sys.cleanup_at_exit")
+            }
+            "c64" -> {
+                asmgen.out("  jsr  p8_main.p8_start |  lda  #31 |  sta  $01")
+                if(!options.noSysInit)
+                    asmgen.out("  jmp  sys.cleanup_at_exit")
+                else
+                    asmgen.out("  rts")
+            }
+            "c128" -> {
+                asmgen.out("  jsr  p8_main.p8_start |  lda  #0 |  sta ${"$"}ff00")
+                if(!options.noSysInit)
+                    asmgen.out("  jmp  sys.cleanup_at_exit")
+                else
+                    asmgen.out("  rts")
+            }
+            else -> asmgen.jmp("p8_main.p8_start")
+        }
+    }
+
+    private fun memorySlabs() {
+        if(symboltable.allMemorySlabs.isNotEmpty()) {
+            asmgen.out("; memory slabs\n  .section slabs_BSS")
+            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\n  .send slabs_BSS")
+        }
+    }
+
+    private fun footer() {
+        asmgen.out("; bss sections")
+        asmgen.out("PROG8_VARSHIGH_RAMBANK = ${options.varsHighBank ?: 1}")
+        if(options.varsHighBank!=null) {
+            if(options.compTarget.machine.BSSHIGHRAM_START == 0u || options.compTarget.machine.BSSHIGHRAM_END==0u) {
+                throw AssemblyError("current compilation target hasn't got the high ram area properly defined")
+            }
+            // BSS vars in high ram area, memory() slabs just concatenated at the end of the program.
+            if(symboltable.allMemorySlabs.isNotEmpty()) {
+                asmgen.out("  .dsection slabs_BSS")
+            }
+            asmgen.out("prog8_program_end\t; end of program label for progend()")
+            asmgen.out("  * = ${options.compTarget.machine.BSSHIGHRAM_START.toHex()}")
+            asmgen.out("prog8_bss_section_start")
+            asmgen.out("  .dsection BSS")
+            asmgen.out("  .cerror * >= ${options.compTarget.machine.BSSHIGHRAM_END.toHex()}, \"too many variables for BSS section\"")
+            asmgen.out("prog8_bss_section_size = * - prog8_bss_section_start")
+        } else {
+            // BSS vars followed by memory() slabs, concatenated at the end of the program.
+            asmgen.out("prog8_bss_section_start")
+            asmgen.out("  .dsection BSS")
+            asmgen.out("prog8_bss_section_size = * - prog8_bss_section_start")
+            if(symboltable.allMemorySlabs.isNotEmpty()) {
+                asmgen.out("  .dsection slabs_BSS")
+            }
+            asmgen.out("prog8_program_end\t; end of program label for progend()")
+        }
+    }
+
+    private fun block2asm(block: PtBlock) {
+        asmgen.out("")
+        asmgen.out("; ---- block: '${block.name}' ----")
+        if(block.address!=null)
+            asmgen.out("* = ${block.address!!.toHex()}")
+        else {
+            if(block.alignment==PtBlock.BlockAlignment.WORD)
+                asmgen.out("\t.align 2")
+            else if(block.alignment==PtBlock.BlockAlignment.PAGE)
+                asmgen.out("\t.align $100")
+        }
+
+        asmgen.out("${block.name}\t" + (if(block.forceOutput) ".block" else ".proc"))
+        asmgen.outputSourceLine(block)
+
+        createBlockVariables(block)
+        asmsubs2asm(block.children)
+
+        asmgen.out("")
+
+        val initializers = blockVariableInitializers.getValue(block)
+        val notInitializers = block.children.filterNot { it in initializers }
+        notInitializers.forEach { asmgen.translate(it) }
+
+        // generate subroutine to initialize block-level (global) variables
+        if (initializers.isNotEmpty()) {
+            asmgen.out("prog8_init_vars\t.block")
+            initializers.forEach { assign ->
+                if((assign.value as? PtNumber)?.number != 0.0 || allocator.isZpVar(assign.target.identifier!!.name))
+                    asmgen.translate(assign)
+                // the other variables that should be set to zero are done so as part of the BSS section.
+            }
+            asmgen.out("  rts\n  .bend")
+        }
+
+        asmgen.out(if(block.forceOutput) "\n\t.bend" else "\n\t.pend")
+    }
+
+    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: PtBlock) {
+        val scope = symboltable.lookupUnscopedOrElse(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 translateAsmSubroutine(sub: PtAsmSub) {
+        if(sub.inline) {
+            return      // subroutine gets inlined at call site.
+        }
+
+        asmgen.out("")
+
+        val asmStartScope: String
+        val asmEndScope: String
+        if(sub.definingBlock()!!.forceOutput) {
+            asmStartScope = ".block"
+            asmEndScope = ".bend"
+        } else {
+            asmStartScope = ".proc"
+            asmEndScope = ".pend"
+        }
+
+        if(sub.address!=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.children.forEach { asmgen.translate(it) }
+        asmgen.out("  $asmEndScope")
+    }
+
+
+    internal fun translateSubroutine(sub: PtSub) {
+        asmgen.out("")
+
+        val asmStartScope: String
+        val asmEndScope: String
+        if(sub.definingBlock()!!.forceOutput) {
+            asmStartScope = ".block"
+            asmEndScope = ".bend"
+        } else {
+            asmStartScope = ".proc"
+            asmEndScope = ".pend"
+        }
+
+        asmgen.out("${sub.name}\t$asmStartScope")
+
+        val scope = symboltable.lookupOrElse(sub.scopedName) {
+            throw AssemblyError("lookup ${sub.scopedName}")
+        }
+        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.children)
+
+        // the main.start subroutine is the program's entrypoint and should perform some initialization logic
+        if((sub.name=="start" || sub.name=="p8_start") && (sub.definingBlock()!!.name=="main" || sub.definingBlock()!!.name=="p8_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, sub.parameters[0].position, 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, sub.parameters[0].position, variableAsmName = sub.parameters[0].name)
+                val target2 = AsmAssignTarget(TargetStorageKind.VARIABLE, asmgen, sub.parameters[1].type, sub, sub.parameters[1].position, variableAsmName = sub.parameters[1].name)
+                asmgen.assignRegister(RegisterOrPair.A, target1)
+                asmgen.assignRegister(RegisterOrPair.Y, target2)
+            }
+        }
+
+        asmgen.out("; statements")
+        sub.children.forEach { asmgen.translate(it) }
+
+        asmgen.out("; variables")
+        asmgen.out("    .section BSS")
+        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  ?")
+                DataType.UWORD -> asmgen.out("$name    .word  ?")
+                DataType.FLOAT -> asmgen.out("$name    .fill  ${options.compTarget.machine.FLOAT_MEM_SIZE}")
+                else -> throw AssemblyError("weird dt for extravar $dt")
+            }
+        }
+        if(asmGenInfo.usedFloatEvalResultVar1)
+            asmgen.out("$subroutineFloatEvalResultVar1    .fill  ${options.compTarget.machine.FLOAT_MEM_SIZE}")
+        if(asmGenInfo.usedFloatEvalResultVar2)
+            asmgen.out("$subroutineFloatEvalResultVar2    .fill  ${options.compTarget.machine.FLOAT_MEM_SIZE}")
+        asmgen.out("  .send BSS")
+
+        // 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")
+    }
+
+    private fun entrypointInitialization() {
+        asmgen.out("; program startup initialization")
+        asmgen.out("  cld |  tsx |  stx  prog8_lib.orig_stackpointer    ; required for sys.exit()")
+        // set full BSS area to zero
+        asmgen.out("""
+    .if  prog8_bss_section_size>0
+    ; reset all variables in BSS section to zero
+	lda  #<prog8_bss_section_start
+	ldy  #>prog8_bss_section_start
+	sta  P8ZP_SCRATCH_W1
+	sty  P8ZP_SCRATCH_W1+1
+	ldx  #<prog8_bss_section_size
+	ldy  #>prog8_bss_section_size
+	lda  #0
+	jsr  prog8_lib.memset
+    .endif""")
+
+        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  #>${name}_init_value
+                    sta  cx16.r0
+                    sty  cx16.r0+1
+                    lda  #<${name}
+                    ldy  #>${name}
+                    sta  cx16.r1
+                    sty  cx16.r1+1
+                    lda  #<$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("""+        
+                    clv
+                    clc""")
+    }
+
+    private class ZpStringWithInitial(
+        val name: String,
+        val alloc: MemoryAllocator.VarAllocation,
+        val value: Pair<String, Encoding>
+    )
+
+    private class ZpArrayWithInitial(
+        val name: String,
+        val alloc: MemoryAllocator.VarAllocation,
+        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 scopedName = variable.key
+            val svar = symboltable.lookup(scopedName) as? StStaticVariable
+            if(svar?.onetimeInitializationStringValue!=null)
+                result.add(ZpStringWithInitial(scopedName, 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 scopedName = variable.key
+            val svar = symboltable.lookup(scopedName) as? StStaticVariable
+            if(svar?.onetimeInitializationArrayValue!=null)
+                result.add(ZpArrayWithInitial(scopedName, variable.value, svar.onetimeInitializationArrayValue!!))
+        }
+        return result
+    }
+
+    private fun zeropagevars2asm(varNames: Set<String>) {
+        val zpVariables = allocator.zeropageVars.filter { it.key in varNames }.toList().sortedBy { it.second.address }
+        for ((scopedName, zpvar) in zpVariables) {
+            if (scopedName.startsWith("cx16.r"))
+                continue        // The 16 virtual registers of the cx16 are not actual variables in zp, they're memory mapped
+            val variable = symboltable.flat.getValue(scopedName) as StStaticVariable
+            if(variable.dt in SplitWordArrayTypes) {
+                val lsbAddr = zpvar.address
+                val msbAddr = zpvar.address + (zpvar.size/2).toUInt()
+                asmgen.out("${scopedName.substringAfterLast('.')}_lsb \t= $lsbAddr \t; zp ${zpvar.dt} (lsbs)")
+                asmgen.out("${scopedName.substringAfterLast('.')}_msb \t= $msbAddr \t; zp ${zpvar.dt} (msbs)")
+            } else {
+                asmgen.out("${scopedName.substringAfterLast('.')} \t= ${zpvar.address} \t; zp ${zpvar.dt}")
+            }
+        }
+    }
+
+    private fun nonZpVariables2asm(variables: List<StStaticVariable>) {
+        asmgen.out("")
+        val (varsNoInit, varsWithInit) = variables.partition { it.uninitialized }
+        if(varsNoInit.isNotEmpty()) {
+            asmgen.out("; non-zeropage variables without initialization value")
+            asmgen.out("  .section BSS")
+            varsNoInit.sortedWith(compareBy<StStaticVariable> { it.name }.thenBy { it.dt }).forEach {
+                uninitializedVariable2asm(it)
+            }
+            asmgen.out("  .send BSS")
+        }
+
+        if(varsWithInit.isNotEmpty()) {
+            asmgen.out("; non-zeropage variables")
+            val (stringvars, othervars) = varsWithInit.sortedBy { it.name }.partition { it.dt == DataType.STR }
+            stringvars.forEach {
+                outputStringvar(
+                    it.name,
+                    it.onetimeInitializationStringValue!!.second,
+                    it.onetimeInitializationStringValue!!.first
+                )
+            }
+            othervars.sortedBy { it.type }.forEach {
+                staticVariable2asm(it)
+            }
+        }
+    }
+
+    private fun uninitializedVariable2asm(variable: StStaticVariable) {
+        when (variable.dt) {
+            DataType.UBYTE -> asmgen.out("${variable.name}\t.byte  ?")
+            DataType.BYTE -> asmgen.out("${variable.name}\t.char  ?")
+            DataType.UWORD -> asmgen.out("${variable.name}\t.word  ?")
+            DataType.WORD -> asmgen.out("${variable.name}\t.sint  ?")
+            DataType.FLOAT -> asmgen.out("${variable.name}\t.fill  ${compTarget.machine.FLOAT_MEM_SIZE}")
+            in SplitWordArrayTypes -> {
+                val numbytesPerHalf = compTarget.memorySize(variable.dt, variable.length!!) / 2
+                asmgen.out("${variable.name}_lsb\t.fill  $numbytesPerHalf")
+                asmgen.out("${variable.name}_msb\t.fill  $numbytesPerHalf")
+            }
+            in ArrayDatatypes -> {
+                val numbytes = compTarget.memorySize(variable.dt, variable.length!!)
+                asmgen.out("${variable.name}\t.fill  $numbytes")
+            }
+            else -> {
+                throw AssemblyError("weird dt")
+            }
+        }
+    }
+
+    private fun staticVariable2asm(variable: StStaticVariable) {
+        val initialValue: Number =
+            if(variable.onetimeInitializationNumericValue!=null) {
+                if(variable.dt== DataType.FLOAT)
+                    variable.onetimeInitializationNumericValue!!
+                else
+                    variable.onetimeInitializationNumericValue!!.toInt()
+            } else 0
+
+        when (variable.dt) {
+            DataType.UBYTE -> asmgen.out("${variable.name}\t.byte  ${initialValue.toHex()}")
+            DataType.BYTE -> asmgen.out("${variable.name}\t.char  $initialValue")
+            DataType.UWORD -> asmgen.out("${variable.name}\t.word  ${initialValue.toHex()}")
+            DataType.WORD -> asmgen.out("${variable.name}\t.sint  $initialValue")
+            DataType.FLOAT -> {
+                if(initialValue==0) {
+                    asmgen.out("${variable.name}\t.byte  0,0,0,0,0  ; float")
+                } else {
+                    val floatFill = compTarget.machine.getFloatAsmBytes(initialValue)
+                    asmgen.out("${variable.name}\t.byte  $floatFill  ; float $initialValue")
+                }
+            }
+            DataType.STR -> {
+                throw AssemblyError("all string vars should have been interned into prog")
+            }
+            in ArrayDatatypes -> arrayVariable2asm(variable.name, variable.dt, variable.onetimeInitializationArrayValue, variable.length)
+            else -> {
+                throw AssemblyError("weird dt")
+            }
+        }
+    }
+
+    private fun arrayVariable2asm(varname: String, dt: DataType, value: StArray?, orNumberOfZeros: Int?) {
+        when(dt) {
+            DataType.ARRAY_UB -> {
+                val data = makeArrayFillDataUnsigned(dt, value, orNumberOfZeros)
+                if (data.size <= 16)
+                    asmgen.out("$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  ${data.joinToString()}")
+                else {
+                    asmgen.out(varname)
+                    for (chunk in data.chunked(16))
+                        asmgen.out("  .sint  " + chunk.joinToString())
+                }
+            }
+            DataType.ARRAY_UW_SPLIT -> {
+                val data = makeArrayFillDataUnsigned(dt, value, orNumberOfZeros)
+                asmgen.out("_array_$varname := ${data.joinToString()}")
+                asmgen.out("${varname}_lsb\t.byte <_array_$varname")
+                asmgen.out("${varname}_msb\t.byte >_array_$varname")
+            }
+            DataType.ARRAY_W_SPLIT -> {
+                val data = makeArrayFillDataSigned(dt, value, orNumberOfZeros)
+                asmgen.out("_array_$varname := ${data.joinToString()}")
+                asmgen.out("${varname}_lsb\t.byte <_array_$varname")
+                asmgen.out("${varname}_msb\t.byte >_array_$varname")
+            }
+            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.sortedBy { it.address }.forEach {
+            asmgen.out("  ${it.name} = ${it.address.toHex()}")
+        }
+        consts.sortedBy { it.name }.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<PtNode>) {
+        statements
+            .filter { it is PtAsmSub && it.address!=null }
+            .forEach { asmsub ->
+                asmsub as PtAsmSub
+                asmgen.out("  ${asmsub.name} = ${asmsub.address!!.toHex()}")
+            }
+    }
+
+    private fun outputStringvar(varname: String, encoding: Encoding, value: String) {
+        asmgen.out("$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, DataType.ARRAY_UW_SPLIT -> array.map {
+                if(it.number!=null) {
+                    "$" + it.number!!.toInt().toString(16).padStart(4, '0')
+                }
+                else if(it.addressOfSymbol!=null) {
+                    asmgen.asmSymbolName(it.addressOfSymbol!!)
+                }
+                else
+                    throw AssemblyError("weird array elt")
+            }
+            else -> throw AssemblyError("invalid dt")
+        }
+    }
+
+    private fun makeArrayFillDataSigned(dt: DataType, value: StArray?, orNumberOfZeros: Int?): List<String> {
+        val array = value ?: zeroFilledArray(orNumberOfZeros!!)
+        return when (dt) {
+            // byte array can never contain pointer-to types, so treat values as all integers
+            DataType.ARRAY_UB ->
+                array.map {
+                    val number = it.number!!.toInt()
+                    "$"+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, DataType.ARRAY_UW_SPLIT -> array.map {
+                val number = it.number!!.toInt()
+                "$" + number.toString(16).padStart(4, '0')
+            }
+            DataType.ARRAY_W, DataType.ARRAY_W_SPLIT -> 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")
+        }
+    }
+
+}
@@ -0,0 +1,131 @@
+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<String, MemoryAllocator.VarAllocation>
+
+    init {
+        allocateZeropageVariables()
+        zeropageVars = zeropage.allocatedVariables
+    }
+
+    internal fun isZpVar(scopedName: String) = scopedName in zeropageVars
+
+    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.astNode.position,
+                errors
+            )
+            result.fold(
+                success = {
+                    numVariablesAllocatedInZP++
+                },
+                failure = {
+                    errors.err(it.message!!, variable.astNode.position)
+                }
+            )
+        }
+
+        if(errors.noErrors()) {
+            varsPreferringZp.forEach { variable ->
+                val result = zeropage.allocate(
+                    variable.scopedName,
+                    variable.dt,
+                    variable.length,
+                    variable.astNode.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()) {
+                val sortedList = varsDontCare.sortedByDescending { it.scopedName }
+                for (variable in sortedList) {
+                    if(variable.dt in IntegerDatatypes) {
+                        if(zeropage.free.isEmpty()) {
+                            break
+                        } else {
+                            val result = zeropage.allocate(
+                                variable.scopedName,
+                                variable.dt,
+                                variable.length,
+                                variable.astNode.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.sortedBy { it.dt }
+    }
+}
@@ -0,0 +1,281 @@
+package prog8.codegen.cpu6502.assignment
+
+import prog8.code.ast.PtBinaryExpression
+import prog8.code.ast.PtExpression
+import prog8.code.core.*
+import prog8.code.target.C64Target
+import prog8.code.target.Cx16Target
+import prog8.codegen.cpu6502.AsmGen6502Internal
+
+//
+// This contains codegen for stack-based evaluation of binary expressions.
+// It uses the CPU stack so depth is limited.
+// It is called "as a last resort" if the optimized codegen path is unable
+// to come up with a special case of the expression.
+//
+internal class AnyExprAsmGen(
+    private val asmgen: AsmGen6502Internal
+) {
+    fun assignAnyExpressionUsingStack(expr: PtBinaryExpression, assign: AsmAssignment): Boolean {
+        when(expr.type) {
+            in ByteDatatypes -> {
+                if(expr.left.type in ByteDatatypes && expr.right.type in ByteDatatypes)
+                    return assignByteBinExpr(expr, assign)
+                if (expr.left.type in WordDatatypes && expr.right.type in WordDatatypes) {
+                    require(expr.operator in ComparisonOperators)
+                    throw AssemblyError("words operands comparison -> byte, should have been handled by assignOptimizedComparisonWords()")
+                }
+                if (expr.left.type==DataType.FLOAT && expr.right.type==DataType.FLOAT) {
+                    require(expr.operator in ComparisonOperators)
+                    return assignFloatBinExpr(expr, assign)
+                }
+                throw AssemblyError("weird expr operand types: ${expr.left.type} and {${expr.right.type}")
+            }
+            in WordDatatypes -> {
+                require(expr.left.type in WordDatatypes && expr.right.type in WordDatatypes) {
+                    "both operands must be words"
+                }
+                return assignWordBinExpr(expr)
+            }
+            DataType.FLOAT -> {
+                require(expr.left.type==DataType.FLOAT && expr.right.type==DataType.FLOAT) {
+                    "both operands must be floats"
+                }
+                return assignFloatBinExpr(expr, assign)
+            }
+            else -> throw AssemblyError("weird expression type in assignment")
+        }
+    }
+
+    private fun assignWordBinExpr(expr: PtBinaryExpression): Boolean {
+        when(expr.operator) {
+            "+" -> {
+                TODO("word + at ${expr.position}")
+            }
+            "-" -> {
+                TODO("word - at ${expr.position}")
+            }
+            "*" -> {
+                TODO("word * at ${expr.position}")
+            }
+            "/" -> {
+                TODO("word / at ${expr.position}")
+            }
+            "<<" -> {
+                TODO("word << at ${expr.position}")
+            }
+            ">>" -> {
+                TODO("word >> at ${expr.position}")
+            }
+            "%" -> {
+                TODO("word % at ${expr.position}")
+            }
+            "&", "and" -> {
+                TODO("word and at ${expr.position}")
+            }
+            "|", "or" -> {
+                TODO("word or at ${expr.position}")
+            }
+            "^", "xor" -> {
+                TODO("word xor at ${expr.position}")
+            }
+            "==" -> {
+                TODO("word == at ${expr.position}")
+            }
+            "!=" -> {
+                TODO("word != at ${expr.position}")
+            }
+            "<" -> {
+                TODO("word < at ${expr.position}")
+            }
+            "<=" -> {
+                TODO("word <= at ${expr.position}")
+            }
+            ">" -> {
+                TODO("word > at ${expr.position}")
+            }
+            ">=" -> {
+                TODO("word >= at ${expr.position}")
+            }
+            else -> return false
+        }
+    }
+
+    private fun assignByteBinExpr(expr: PtBinaryExpression, assign: AsmAssignment): Boolean {
+        when(expr.operator) {
+            "+" -> {
+                asmgen.assignExpressionToRegister(expr.left, RegisterOrPair.A, false)
+                asmgen.out("  pha")
+                asmgen.assignExpressionToVariable(expr.right, "P8ZP_SCRATCH_B1", DataType.UBYTE)
+                asmgen.out("  pla |  clc |  adc  P8ZP_SCRATCH_B1")
+                asmgen.assignRegister(RegisterOrPair.A, assign.target)
+                return true
+            }
+            "-" -> {
+                asmgen.assignExpressionToRegister(expr.left, RegisterOrPair.A, false)
+                asmgen.out("  pha")
+                asmgen.assignExpressionToVariable(expr.right, "P8ZP_SCRATCH_B1", DataType.UBYTE)
+                asmgen.out("  pla |  sec |  sbc  P8ZP_SCRATCH_B1")
+                asmgen.assignRegister(RegisterOrPair.A, assign.target)
+                return true
+            }
+            "*" -> {
+                TODO("byte * at ${expr.position}")
+            }
+            "/" -> {
+                TODO("byte / at ${expr.position}")
+            }
+            "<<" -> {
+                TODO("byte << at ${expr.position}")
+            }
+            ">>" -> {
+                TODO("byte >> at ${expr.position}")
+            }
+            "%" -> {
+                TODO("byte % at ${expr.position}")
+            }
+            "&", "and" -> {
+                asmgen.assignExpressionToRegister(expr.left, RegisterOrPair.A, false)
+                asmgen.out("  pha")
+                asmgen.assignExpressionToVariable(expr.right, "P8ZP_SCRATCH_B1", DataType.UBYTE)
+                asmgen.out("  pla |  and  P8ZP_SCRATCH_B1")
+                asmgen.assignRegister(RegisterOrPair.A, assign.target)
+                return true
+            }
+            "|", "or" -> {
+                asmgen.assignExpressionToRegister(expr.left, RegisterOrPair.A, false)
+                asmgen.out("  pha")
+                asmgen.assignExpressionToVariable(expr.right, "P8ZP_SCRATCH_B1", DataType.UBYTE)
+                asmgen.out("  pla |  ora  P8ZP_SCRATCH_B1")
+                asmgen.assignRegister(RegisterOrPair.A, assign.target)
+                return true
+            }
+            "^", "xor" -> {
+                asmgen.assignExpressionToRegister(expr.left, RegisterOrPair.A, false)
+                asmgen.out("  pha")
+                asmgen.assignExpressionToVariable(expr.right, "P8ZP_SCRATCH_B1", DataType.UBYTE)
+                asmgen.out("  pla |  eor  P8ZP_SCRATCH_B1")
+                asmgen.assignRegister(RegisterOrPair.A, assign.target)
+                return true
+            }
+            "==" -> {
+                TODO("byte == at ${expr.position}")
+            }
+            "!=" -> {
+                TODO("byte != at ${expr.position}")
+            }
+            "<" -> {
+                TODO("byte < at ${expr.position}")
+            }
+            "<=" -> {
+                TODO("byte <= at ${expr.position}")
+            }
+            ">" -> {
+                TODO("byte > at ${expr.position}")
+            }
+            ">=" -> {
+                TODO("byte >= at ${expr.position}")
+            }
+            else -> return false
+        }
+    }
+
+    private fun assignFloatBinExpr(expr: PtBinaryExpression, assign: AsmAssignment): Boolean {
+        when(expr.operator) {
+            "+" -> {
+                assignFloatOperandsToFACandARG(expr.left, expr.right)
+                asmgen.out("  jsr  floats.FADDT")
+                asmgen.assignRegister(RegisterOrPair.FAC1, assign.target)
+                return true
+            }
+            "-" -> {
+                assignFloatOperandsToFACandARG(expr.right, expr.left)
+                asmgen.out("  jsr  floats.FSUBT")
+                asmgen.assignRegister(RegisterOrPair.FAC1, assign.target)
+                return true
+            }
+            "*" -> {
+                assignFloatOperandsToFACandARG(expr.left, expr.right)
+                asmgen.out("  jsr  floats.FMULTT")
+                asmgen.assignRegister(RegisterOrPair.FAC1, assign.target)
+                return true
+            }
+            "/" -> {
+                assignFloatOperandsToFACandARG(expr.right, expr.left)
+                asmgen.out("  jsr  floats.FDIVT")
+                asmgen.assignRegister(RegisterOrPair.FAC1, assign.target)
+                return true
+            }
+            "==" -> {
+                setupFloatComparisonFAC1vsVarAY(expr)
+                asmgen.out("  jsr  floats.var_fac1_equal_f")
+                asmgen.assignRegister(RegisterOrPair.A, assign.target)
+                return true
+            }
+            "!=" -> {
+                setupFloatComparisonFAC1vsVarAY(expr)
+                asmgen.out("  jsr  floats.var_fac1_notequal_f")
+                asmgen.assignRegister(RegisterOrPair.A, assign.target)
+                return true
+            }
+            "<" -> {
+                setupFloatComparisonFAC1vsVarAY(expr)
+                asmgen.out("  jsr  floats.var_fac1_less_f")
+                asmgen.assignRegister(RegisterOrPair.A, assign.target)
+                return true
+            }
+            ">" -> {
+                setupFloatComparisonFAC1vsVarAY(expr)
+                asmgen.out("  jsr  floats.var_fac1_greater_f")
+                asmgen.assignRegister(RegisterOrPair.A, assign.target)
+                return true
+            }
+            "<=" -> {
+                setupFloatComparisonFAC1vsVarAY(expr)
+                asmgen.out("  jsr  floats.var_fac1_lesseq_f")
+                asmgen.assignRegister(RegisterOrPair.A, assign.target)
+                return true
+            }
+            ">=" -> {
+                setupFloatComparisonFAC1vsVarAY(expr)
+                asmgen.out("  jsr  floats.var_fac1_greatereq_f")
+                asmgen.assignRegister(RegisterOrPair.A, assign.target)
+                return true
+            }
+            else -> TODO("float expression operator ${expr.operator}")
+        }
+    }
+
+    private fun assignFloatOperandsToFACandARG(left: PtExpression, right: PtExpression) {
+        when(asmgen.options.compTarget.name) {
+            C64Target.NAME -> {
+                // c64 has a quirk: always make sure FAC2 is loaded last (done using CONUPK)  otherwise the result will be corrupt on C64
+                // this requires some more forced copying around of float values in certain cases
+                if (right.isSimple()) {
+                    asmgen.assignExpressionToRegister(left, RegisterOrPair.FAC1, true)
+                    asmgen.assignExpressionToRegister(right, RegisterOrPair.FAC2, true)
+                } else {
+                    asmgen.assignExpressionToRegister(right, RegisterOrPair.FAC1, true)
+                    asmgen.pushFAC1()
+                    asmgen.assignExpressionToRegister(left, RegisterOrPair.FAC1, true)
+                    asmgen.popFAC2()
+                }
+            }
+            Cx16Target.NAME -> {
+                asmgen.assignExpressionToRegister(left, RegisterOrPair.FAC1, true)
+                if (!right.isSimple()) asmgen.pushFAC1()
+                asmgen.assignExpressionToRegister(right, RegisterOrPair.FAC2, true)
+                if (!right.isSimple()) asmgen.popFAC1()
+            }
+            else -> TODO("don't know how to evaluate float expression for selected compilation target")
+        }
+    }
+
+    private fun setupFloatComparisonFAC1vsVarAY(expr: PtBinaryExpression) {
+        asmgen.assignExpressionToRegister(expr.left, RegisterOrPair.FAC1, true)
+        if(!expr.right.isSimple()) asmgen.pushFAC1()
+        asmgen.assignExpressionToVariable(expr.right, "floats.floats_temp_var", DataType.FLOAT)
+        if(!expr.right.isSimple()) asmgen.popFAC1()
+        asmgen.out("  lda  #<floats.floats_temp_var |  ldy  #>floats.floats_temp_var")
+    }
+}
@@ -0,0 +1,235 @@
+package prog8.codegen.cpu6502.assignment
+
+import prog8.code.ast.*
+import prog8.code.core.*
+import prog8.codegen.cpu6502.AsmGen6502Internal
+import prog8.codegen.cpu6502.returnsWhatWhere
+
+
+internal enum class TargetStorageKind {
+    VARIABLE,
+    ARRAY,
+    MEMORY,
+    REGISTER
+}
+
+internal enum class SourceStorageKind {
+    LITERALNUMBER,
+    VARIABLE,
+    ARRAY,
+    MEMORY,
+    REGISTER,
+    EXPRESSION,         // expression in ast-form, still to be evaluated
+}
+
+internal class AsmAssignTarget(val kind: TargetStorageKind,
+                               private val asmgen: AsmGen6502Internal,
+                               val datatype: DataType,
+                               val scope: IPtSubroutine?,
+                               val position: Position,
+                               private val variableAsmName: String? = null,
+                               val array: PtArrayIndexer? = null,
+                               val memory: PtMemoryByte? = null,
+                               val register: RegisterOrPair? = null,
+                               val origAstTarget: PtAssignTarget? = null
+                               )
+{
+    val constArrayIndexValue by lazy { array?.index?.asConstInteger()?.toUInt() }
+    val asmVarname: String by lazy {
+        if (array == null)
+            variableAsmName!!
+        else
+            asmgen.asmVariableName(array.variable)
+    }
+
+    init {
+        if(register!=null && datatype !in NumericDatatypes)
+            throw AssemblyError("register must be integer or float type")
+    }
+
+    companion object {
+        fun fromAstAssignment(target: PtAssignTarget, definingSub: IPtSubroutine?, asmgen: AsmGen6502Internal): AsmAssignTarget {
+            with(target) {
+                when {
+                    identifier != null -> {
+                        val parameter = asmgen.findSubroutineParameter(identifier!!.name, asmgen)
+                        if (parameter!=null) {
+                            val sub = parameter.definingAsmSub()
+                            if (sub!=null) {
+                                val reg = sub.parameters.single { it.second===parameter }.first
+                                if(reg.statusflag!=null)
+                                    throw AssemblyError("can't assign value to processor statusflag directly")
+                                else
+                                    return AsmAssignTarget(TargetStorageKind.REGISTER, asmgen, type, definingSub, target.position, register=reg.registerOrPair, origAstTarget = this)
+                            }
+                        }
+                        return AsmAssignTarget(TargetStorageKind.VARIABLE, asmgen, type, definingSub, target.position, variableAsmName = asmgen.asmVariableName(identifier!!), origAstTarget =  this)
+                    }
+                    array != null -> return AsmAssignTarget(TargetStorageKind.ARRAY, asmgen, type, definingSub, target.position, array = array, origAstTarget =  this)
+                    memory != null -> return AsmAssignTarget(TargetStorageKind.MEMORY, asmgen, type, definingSub, target.position, memory =  memory, origAstTarget =  this)
+                    else -> throw AssemblyError("weird target")
+                }
+            }
+        }
+
+        fun fromRegisters(registers: RegisterOrPair, signed: Boolean, pos: Position, scope: IPtSubroutine?, asmgen: AsmGen6502Internal): AsmAssignTarget =
+                when(registers) {
+                    RegisterOrPair.A,
+                    RegisterOrPair.X,
+                    RegisterOrPair.Y -> AsmAssignTarget(TargetStorageKind.REGISTER, asmgen, if(signed) DataType.BYTE else DataType.UBYTE, scope, pos, register = registers)
+                    RegisterOrPair.AX,
+                    RegisterOrPair.AY,
+                    RegisterOrPair.XY -> AsmAssignTarget(TargetStorageKind.REGISTER, asmgen, if(signed) DataType.WORD else DataType.UWORD, scope, pos, register = registers)
+                    RegisterOrPair.FAC1,
+                    RegisterOrPair.FAC2 -> AsmAssignTarget(TargetStorageKind.REGISTER, asmgen, DataType.FLOAT, scope, pos, 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, pos, register = registers)
+                }
+    }
+
+    fun isSameAs(left: PtExpression): Boolean =
+        when(kind) {
+            TargetStorageKind.VARIABLE -> {
+                val scopedName: String = if('.' in asmVarname)
+                    asmVarname
+                else {
+                    val scopeName = (scope as? PtNamedNode)?.scopedName
+                    if (scopeName == null) asmVarname else "$scopeName.$asmVarname"
+                }
+                left is PtIdentifier && left.name==scopedName
+            }
+            TargetStorageKind.ARRAY -> {
+                left is PtArrayIndexer && left isSameAs array!! && left.splitWords==array.splitWords
+            }
+            TargetStorageKind.MEMORY -> {
+                left isSameAs memory!!
+            }
+            TargetStorageKind.REGISTER -> {
+                false
+            }
+        }
+}
+
+internal class AsmAssignSource(val kind: SourceStorageKind,
+                               private val program: PtProgram,
+                               private val asmgen: AsmGen6502Internal,
+                               val datatype: DataType,
+                               private val variableAsmName: String? = null,
+                               val array: PtArrayIndexer? = null,
+                               val memory: PtMemoryByte? = null,
+                               val register: RegisterOrPair? = null,
+                               val number: PtNumber? = null,
+                               val expression: PtExpression? = null
+)
+{
+    val asmVarname: String
+        get() = if(array==null)
+            variableAsmName!!
+        else
+            asmgen.asmVariableName(array.variable)
+
+    companion object {
+        fun fromAstSource(value: PtExpression, program: PtProgram, asmgen: AsmGen6502Internal): AsmAssignSource {
+            val cv = value as? PtNumber
+            if(cv!=null)
+                return AsmAssignSource(SourceStorageKind.LITERALNUMBER, program, asmgen, cv.type, number = cv)
+
+            return when(value) {
+                // checked above:   is PtNumber -> throw AssemblyError("should have been constant value")
+                is PtString -> throw AssemblyError("string literal value should not occur anymore for asm generation")
+                is PtArray -> throw AssemblyError("array literal value should not occur anymore for asm generation")
+                is PtIdentifier -> {
+                    val parameter = asmgen.findSubroutineParameter(value.name, asmgen)
+                    if(parameter?.definingAsmSub() != null)
+                        throw AssemblyError("can't assign from a asmsub register parameter $value ${value.position}")
+                    val varName=asmgen.asmVariableName(value)
+                    // special case: "cx16.r[0-15]" are 16-bits virtual registers of the commander X16 system
+                    if(value.type == DataType.UWORD && varName.lowercase().startsWith("cx16.r")) {
+                        val regStr = varName.lowercase().substring(5)
+                        val reg = RegisterOrPair.valueOf(regStr.uppercase())
+                        AsmAssignSource(SourceStorageKind.REGISTER, program, asmgen, value.type, register = reg)
+                    } else {
+                        AsmAssignSource(SourceStorageKind.VARIABLE, program, asmgen, value.type, variableAsmName = varName)
+                    }
+                }
+                is PtMemoryByte -> {
+                    AsmAssignSource(SourceStorageKind.MEMORY, program, asmgen, DataType.UBYTE, memory = value)
+                }
+                is PtArrayIndexer -> {
+                    AsmAssignSource(SourceStorageKind.ARRAY, program, asmgen, value.type, array = value)
+                }
+                is PtBuiltinFunctionCall -> {
+                    AsmAssignSource(SourceStorageKind.EXPRESSION, program, asmgen, value.type, expression = value)
+                }
+                is PtFunctionCall -> {
+                    val symbol = asmgen.symbolTable.lookup(value.name) ?: throw AssemblyError("lookup error ${value.name}")
+                    val sub = symbol.astNode as IPtSubroutine
+                    val returnType = sub.returnsWhatWhere().firstOrNull { rr -> rr.first.registerOrPair != null || rr.first.statusflag!=null }?.second
+                            ?: throw AssemblyError("can't translate zero return values in assignment")
+
+                    AsmAssignSource(SourceStorageKind.EXPRESSION, program, asmgen, returnType, expression = value)
+                }
+                else -> {
+                    AsmAssignSource(SourceStorageKind.EXPRESSION, program, asmgen, value.type, 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 sealed class AsmAssignmentBase(val source: AsmAssignSource,
+                                        val target: AsmAssignTarget,
+                                        val 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 at $position" }
+            require(memsizer.memorySize(source.datatype) <= memsizer.memorySize(target.datatype)) {
+                "source dt size must be less or equal to target dt size at $position srcdt=${source.datatype} targetdt=${target.datatype}"
+            }
+    }
+}
+
+internal class AsmAssignment(source: AsmAssignSource,
+                             target: AsmAssignTarget,
+                             memsizer: IMemSizer,
+                             position: Position): AsmAssignmentBase(source, target, memsizer, position)
+
+internal class AsmAugmentedAssignment(source: AsmAssignSource,
+                                      val operator: String,
+                                      target: AsmAssignTarget,
+                                      memsizer: IMemSizer,
+                                      position: Position): AsmAssignmentBase(source, target, memsizer, position)
+
@@ -0,0 +1,68 @@
+package prog8tests.codegencpu6502
+
+import prog8.code.core.*
+
+
+internal object DummyMemsizer : IMemSizer {
+    override fun memorySize(dt: DataType) = when(dt) {
+        in ByteDatatypes -> 1
+        DataType.FLOAT -> 5
+        else -> 2
+    }
+    override fun memorySize(arrayDt: DataType, numElements: Int) = when(arrayDt) {
+        DataType.ARRAY_UW -> numElements*2
+        DataType.ARRAY_W -> numElements*2
+        DataType.ARRAY_F -> numElements*5
+        else -> numElements
+    }
+}
+
+internal object DummyStringEncoder : IStringEncoding {
+    override fun encodeString(str: String, encoding: Encoding): List<UByte> {
+        return emptyList()
+    }
+
+    override fun decodeString(bytes: Iterable<UByte>, encoding: Encoding): String {
+        return ""
+    }
+}
+
+internal class ErrorReporterForTests(private val throwExceptionAtReportIfErrors: Boolean=true, private val keepMessagesAfterReporting: Boolean=false):
+    IErrorReporter {
+
+    val errors = mutableListOf<String>()
+    val warnings = mutableListOf<String>()
+
+    override fun err(msg: String, position: Position) {
+        val text = "${position.toClickableStr()} $msg"
+        if(text !in errors)
+            errors.add(text)
+    }
+
+    override fun warn(msg: String, position: Position) {
+        val text = "${position.toClickableStr()} $msg"
+        if(text !in warnings)
+            warnings.add(text)
+    }
+
+    override fun undefined(symbol: List<String>, position: Position) {
+        err("undefined symbol: ${symbol.joinToString(".")}", position)
+    }
+
+    override fun noErrors(): Boolean  = errors.isEmpty()
+
+    override fun report() {
+        warnings.forEach { println("UNITTEST COMPILATION REPORT: WARNING: $it") }
+        errors.forEach { println("UNITTEST COMPILATION REPORT: ERROR: $it") }
+        if(throwExceptionAtReportIfErrors)
+            finalizeNumErrors(errors.size, warnings.size)
+        if(!keepMessagesAfterReporting) {
+            clear()
+        }
+    }
+
+    fun clear() {
+        errors.clear()
+        warnings.clear()
+    }
+}
@@ -0,0 +1,129 @@
+package prog8tests.codegencpu6502
+
+import io.kotest.assertions.throwables.shouldNotThrowAny
+import io.kotest.assertions.withClue
+import io.kotest.core.spec.style.FunSpec
+import io.kotest.matchers.ints.shouldBeGreaterThanOrEqual
+import io.kotest.matchers.shouldBe
+import prog8.code.SymbolTableMaker
+import prog8.code.ast.*
+import prog8.code.core.*
+import prog8.code.target.C64Target
+import prog8.codegen.cpu6502.AsmGen6502
+import java.nio.file.Files
+import kotlin.io.path.Path
+
+class TestCodegen: FunSpec({
+
+    fun getTestOptions(): CompilationOptions {
+        val target = C64Target()
+        return CompilationOptions(
+            OutputType.RAW,
+            CbmPrgLauncherType.NONE,
+            ZeropageType.DONTUSE,
+            zpReserved = emptyList(),
+            zpAllowed = CompilationOptions.AllZeropageAllowed,
+            floats = true,
+            noSysInit = false,
+            compTarget = target,
+            loadAddress = target.machine.PROGRAM_LOAD_ADDRESS
+        )
+    }
+
+    test("augmented assign on arrays") {
+//main {
+//    sub start() {
+//        ubyte[] particleX = [1,2,3]
+//        ubyte[] particleDX = [1,2,3]
+//        particleX[2] += particleDX[2]
+//
+//        word @shared xx = 1
+//        xx = -xx
+//        xx += 42
+//        xx += cx16.r0
+//    }
+//}
+        val codegen = AsmGen6502(prefixSymbols = false)
+        val program = PtProgram("test", DummyMemsizer, DummyStringEncoder)
+        val block = PtBlock("main", null, false, false, false, false, PtBlock.BlockAlignment.NONE, SourceCode.Generated("test"), Position.DUMMY)
+        val sub = PtSub("start", emptyList(), null, Position.DUMMY)
+        sub.add(PtVariable("pi", DataType.UBYTE, ZeropageWish.DONTCARE, PtNumber(DataType.UBYTE, 0.0, Position.DUMMY), null, Position.DUMMY))
+        sub.add(PtVariable("particleX", DataType.ARRAY_UB, ZeropageWish.DONTCARE, null, 3u, Position.DUMMY))
+        sub.add(PtVariable("particleDX", DataType.ARRAY_UB, ZeropageWish.DONTCARE, null, 3u, Position.DUMMY))
+        sub.add(PtVariable("xx", DataType.WORD, ZeropageWish.DONTCARE, PtNumber(DataType.WORD, 1.0, Position.DUMMY), null, Position.DUMMY))
+
+        val assign = PtAugmentedAssign("+=", Position.DUMMY)
+        val target = PtAssignTarget(Position.DUMMY).also {
+            val targetIdx = PtArrayIndexer(DataType.UBYTE, Position.DUMMY).also { idx ->
+                idx.add(PtIdentifier("main.start.particleX", DataType.ARRAY_UB, Position.DUMMY))
+                idx.add(PtNumber(DataType.UBYTE, 2.0, Position.DUMMY))
+            }
+            it.add(targetIdx)
+        }
+        val value = PtArrayIndexer(DataType.UBYTE, Position.DUMMY)
+        value.add(PtIdentifier("main.start.particleDX", DataType.ARRAY_UB, Position.DUMMY))
+        value.add(PtNumber(DataType.UBYTE, 2.0, Position.DUMMY))
+        assign.add(target)
+        assign.add(value)
+        sub.add(assign)
+
+        val prefixAssign = PtAugmentedAssign("-", Position.DUMMY)
+        val prefixTarget = PtAssignTarget(Position.DUMMY).also {
+            it.add(PtIdentifier("main.start.xx", DataType.WORD, Position.DUMMY))
+        }
+        prefixAssign.add(prefixTarget)
+        prefixAssign.add(PtIdentifier("main.start.xx", DataType.WORD, Position.DUMMY))
+        sub.add(prefixAssign)
+
+        val numberAssign = PtAugmentedAssign("-=", Position.DUMMY)
+        val numberAssignTarget = PtAssignTarget(Position.DUMMY).also {
+            it.add(PtIdentifier("main.start.xx", DataType.WORD, Position.DUMMY))
+        }
+        numberAssign.add(numberAssignTarget)
+        numberAssign.add(PtNumber(DataType.WORD, 42.0, Position.DUMMY))
+        sub.add(numberAssign)
+
+        val cxregAssign = PtAugmentedAssign("+=", Position.DUMMY)
+        val cxregAssignTarget = PtAssignTarget(Position.DUMMY).also {
+            it.add(PtIdentifier("main.start.xx", DataType.WORD, Position.DUMMY))
+        }
+        cxregAssign.add(cxregAssignTarget)
+        cxregAssign.add(PtIdentifier("cx16.r0", DataType.UWORD, Position.DUMMY))
+        sub.add(cxregAssign)
+
+        block.add(sub)
+        program.add(block)
+
+        // define the "cx16.r0" virtual register
+        val cx16block = PtBlock("cx16", null, false, false, false, false, PtBlock.BlockAlignment.NONE, SourceCode.Generated("test"), Position.DUMMY)
+        cx16block.add(PtMemMapped("r0", DataType.UWORD, 100u, null, Position.DUMMY))
+        program.add(cx16block)
+
+        val options = getTestOptions()
+        val st = SymbolTableMaker(program, options).make()
+        val errors = ErrorReporterForTests()
+        val result = codegen.generate(program, st, options, errors)!!
+        result.name shouldBe "test"
+        Files.deleteIfExists(Path("${result.name}.asm"))
+    }
+
+    test("64tass assembler available? - if this fails you need to install 64tass version 1.58 or newer in the path") {
+        val command = mutableListOf("64tass", "--version")
+        shouldNotThrowAny {
+            val proc = ProcessBuilder(command).start()
+            val output = String(proc.inputStream.readBytes())
+            val result = proc.waitFor()
+            result.shouldBe(0)
+            val (_, version) = output.split('V')
+            val (major, minor, _) = version.split('.')
+            val majorNum = major.toInt()
+            val minorNum = minor.toInt()
+            withClue("64tass version should be 1.58 or newer") {
+                majorNum shouldBeGreaterThanOrEqual 1
+                if (majorNum == 1)
+                    minorNum shouldBeGreaterThanOrEqual 58
+            }
+        }
+    }
+})
+
@@ -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:1.1.18"
+
+}
+
+sourceSets {
+    main {
+        java {
+            srcDir "${project.projectDir}/src"
+        }
+        resources {
+            srcDir "${project.projectDir}/res"
+        }
+    }
+}
+
+// note: there are no unit tests in this module!
@@ -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>