version 9.4

fix register stack saving on certain expression code that was broken on 6502 but not on 65c02
fix shadowing warnings in asm and library code
2026-10-22 05:02:58 +00:00 · 2023-08-29 12:27:09 +02:00 · 2023-08-29 11:50:35 +02:00 · 2023-08-29 11:00:53 +02:00 · 2023-08-28 16:55:28 +02:00 · 2023-08-28 16:45:59 +02:00
568 changed files with 80707 additions and 31784 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
@@ -15,6 +15,7 @@ out/
 parser/**/*.interp
 parser/**/*.tokens
 parser/**/*.java
+compiler/src/prog8/buildversion/*
 *.py[cod]
 *.egg
 *.egg-info
@@ -26,6 +27,11 @@ parser.out
 parsetab.py
 .pytest_cache/
 .attach_pid*
+compiler/lib/

 .gradle
+**/BuildVersion.kt
 /prog8compiler.jar
+sd*.img
+*.d64
+
@@ -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>
@@ -3,14 +3,12 @@
    <option name="myName" value="Project Default" />
    <inspection_tool class="DuplicatedCode" enabled="true" level="WEAK WARNING" enabled_by_default="true">
      <Languages>
-        <language minSize="100" isEnabled="false" name="JavaScript" />
-        <language isEnabled="false" name="Groovy" />
-        <language isEnabled="false" name="Style Sheets" />
        <language minSize="70" name="Kotlin" />
-        <language isEnabled="false" name="TypeScript" />
-        <language isEnabled="false" name="ActionScript" />
+        <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" />
@@ -1,6 +1,9 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project version="4">
  <component name="Kotlin2JvmCompilerArguments">
-    <option name="jvmTarget" value="1.8" />
+    <option name="jvmTarget" value="11" />
+  </component>
+  <component name="KotlinJpsPluginSettings">
+    <option name="version" value="1.9.0-release-358" />
  </component>
 </project>
@@ -1,9 +0,0 @@
-<component name="libraryTable">
-  <library name="antlr-4.7.2-complete">
-    <CLASSES>
-      <root url="jar://$PROJECT_DIR$/parser/antlr/lib/antlr-4.7.2-complete.jar!/" />
-    </CLASSES>
-    <JAVADOC />
-    <SOURCES />
-  </library>
-</component>
@@ -1,9 +0,0 @@
-<component name="libraryTable">
-  <library name="antlr-4.8-complete">
-    <CLASSES>
-      <root url="jar://$PROJECT_DIR$/parser/antlr/lib/antlr-4.8-complete.jar!/" />
-    </CLASSES>
-    <JAVADOC />
-    <SOURCES />
-  </library>
-</component>
@@ -0,0 +1,18 @@
+<component name="libraryTable">
+  <library name="antlr.antlr4" type="repository">
+    <properties maven-id="org.antlr:antlr4:4.12.0">
+      <exclude>
+        <dependency maven-id="com.ibm.icu:icu4j" />
+      </exclude>
+    </properties>
+    <CLASSES>
+      <root url="jar://$MAVEN_REPOSITORY$/org/antlr/antlr4/4.12.0/antlr4-4.12.0.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/antlr/antlr4-runtime/4.12.0/antlr4-runtime-4.12.0.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>
@@ -1,9 +0,0 @@
-<component name="libraryTable">
-  <library name="antlr-runtime-4.7.2">
-    <CLASSES>
-      <root url="jar://$PROJECT_DIR$/parser/antlr/lib/antlr-runtime-4.7.2.jar!/" />
-    </CLASSES>
-    <JAVADOC />
-    <SOURCES />
-  </library>
-</component>
@@ -1,9 +0,0 @@
-<component name="libraryTable">
-  <library name="antlr-runtime-4.8">
-    <CLASSES>
-      <root url="jar://$PROJECT_DIR$/parser/antlr/lib/antlr-runtime-4.8.jar!/" />
-    </CLASSES>
-    <JAVADOC />
-    <SOURCES />
-  </library>
-</component>
@@ -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:5.6.2" />
+    <CLASSES>
+      <root url="jar://$MAVEN_REPOSITORY$/io/kotest/kotest-assertions-core-jvm/5.6.2/kotest-assertions-core-jvm-5.6.2.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/5.6.2/kotest-assertions-shared-jvm-5.6.2.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/1.2.0/opentest4j-1.2.0.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/5.6.2/kotest-common-jvm-5.6.2.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/io/kotest/kotest-assertions-api-jvm/5.6.2/kotest-assertions-api-jvm-5.6.2.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:5.6.2" />
+    <CLASSES>
+      <root url="jar://$MAVEN_REPOSITORY$/io/kotest/kotest-runner-junit5-jvm/5.6.2/kotest-runner-junit5-jvm-5.6.2.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/io/kotest/kotest-framework-api-jvm/5.6.2/kotest-framework-api-jvm-5.6.2.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/io/kotest/kotest-assertions-shared-jvm/5.6.2/kotest-assertions-shared-jvm-5.6.2.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/5.6.2/kotest-common-jvm-5.6.2.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/io/kotest/kotest-framework-engine-jvm/5.6.2/kotest-framework-engine-jvm-5.6.2.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/io/github/classgraph/classgraph/4.8.157/classgraph-4.8.157.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/1.2.0/opentest4j-1.2.0.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/5.6.2/kotest-framework-discovery-jvm-5.6.2.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/io/kotest/kotest-assertions-core-jvm/5.6.2/kotest-assertions-core-jvm-5.6.2.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/5.6.2/kotest-assertions-api-jvm-5.6.2.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/io/kotest/kotest-extensions-jvm/5.6.2/kotest-extensions-jvm-5.6.2.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/io/kotest/kotest-framework-concurrency-jvm/5.6.2/kotest-framework-concurrency-jvm-5.6.2.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:0.3.5" />
+    <CLASSES>
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/kotlinx/kotlinx-cli-jvm/0.3.5/kotlinx-cli-jvm-0.3.5.jar!/" />
+    </CLASSES>
+    <JAVADOC />
+    <SOURCES />
+  </library>
+</component>
@@ -1,9 +0,0 @@
-<component name="libraryTable">
-  <library name="kotlinx-cli-jvm-0.1.0-dev-5">
-    <CLASSES>
-      <root url="jar://$PROJECT_DIR$/compiler/lib/kotlinx-cli-jvm-0.1.0-dev-5.jar!/" />
-    </CLASSES>
-    <JAVADOC />
-    <SOURCES />
-  </library>
-</component>
@@ -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:2.0.7" />
+    <CLASSES>
+      <root url="jar://$MAVEN_REPOSITORY$/org/slf4j/slf4j-simple/2.0.7/slf4j-simple-2.0.7.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/slf4j/slf4j-api/2.0.7/slf4j-api-2.0.7.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>
@@ -1,10 +0,0 @@
-<component name="libraryTable">
-  <library name="unittest-libs">
-    <CLASSES>
-      <root url="file://$PROJECT_DIR$/compiler/lib" />
-    </CLASSES>
-    <JAVADOC />
-    <SOURCES />
-    <jarDirectory url="file://$PROJECT_DIR$/compiler/lib" recursive="false" />
-  </library>
-</component>
@@ -4,7 +4,7 @@
    <option name="perGrammarGenerationSettings">
      <list>
        <PerGrammarGenerationSettings>
-          <option name="fileName" value="$PROJECT_DIR$/parser/antlr/prog8.g4" />
+          <option name="fileName" value="$PROJECT_DIR$/parser/antlr/Prog8ANTLR.g4" />
          <option name="autoGen" value="true" />
          <option name="outputDir" value="$PROJECT_DIR$/parser/src/prog8/parser" />
          <option name="libDir" value="" />
@@ -16,7 +16,10 @@
      </list>
    </option>
  </component>
-  <component name="ProjectRootManager" version="2" languageLevel="JDK_11" default="false" project-jdk-name="Kotlin SDK" project-jdk-type="KotlinSDK">
+  <component name="FrameworkDetectionExcludesConfiguration">
+    <type id="Python" />
+  </component>
+  <component name="ProjectRootManager" version="2" languageLevel="JDK_11" default="true" project-jdk-name="openjdk-11" project-jdk-type="JavaSDK">
    <output url="file://$PROJECT_DIR$/out" />
  </component>
 </project>
@@ -2,10 +2,21 @@
 <project version="4">
  <component name="ProjectModuleManager">
    <modules>
+      <module fileurl="file://$PROJECT_DIR$/codeCore/codeCore.iml" filepath="$PROJECT_DIR$/codeCore/codeCore.iml" />
+      <module fileurl="file://$PROJECT_DIR$/codeGenCpu6502/codeGenCpu6502.iml" filepath="$PROJECT_DIR$/codeGenCpu6502/codeGenCpu6502.iml" />
+      <module fileurl="file://$PROJECT_DIR$/codeGenExperimental/codeGenExperimental.iml" filepath="$PROJECT_DIR$/codeGenExperimental/codeGenExperimental.iml" />
+      <module fileurl="file://$PROJECT_DIR$/codeGenIntermediate/codeGenIntermediate.iml" filepath="$PROJECT_DIR$/codeGenIntermediate/codeGenIntermediate.iml" />
+      <module fileurl="file://$PROJECT_DIR$/codeGenVirtual/codeGenVirtual.iml" filepath="$PROJECT_DIR$/codeGenVirtual/codeGenVirtual.iml" />
+      <module fileurl="file://$PROJECT_DIR$/codeOptimizers/codeOptimizers.iml" filepath="$PROJECT_DIR$/codeOptimizers/codeOptimizers.iml" />
      <module fileurl="file://$PROJECT_DIR$/compiler/compiler.iml" filepath="$PROJECT_DIR$/compiler/compiler.iml" />
+      <module fileurl="file://$PROJECT_DIR$/compilerAst/compilerAst.iml" filepath="$PROJECT_DIR$/compilerAst/compilerAst.iml" />
+      <module fileurl="file://$PROJECT_DIR$/dbusCompilerService/dbusCompilerService.iml" filepath="$PROJECT_DIR$/dbusCompilerService/dbusCompilerService.iml" />
      <module fileurl="file://$PROJECT_DIR$/docs/docs.iml" filepath="$PROJECT_DIR$/docs/docs.iml" />
      <module fileurl="file://$PROJECT_DIR$/examples/examples.iml" filepath="$PROJECT_DIR$/examples/examples.iml" />
+      <module fileurl="file://$PROJECT_DIR$/httpCompilerService/httpCompilerService.iml" filepath="$PROJECT_DIR$/httpCompilerService/httpCompilerService.iml" />
+      <module fileurl="file://$PROJECT_DIR$/intermediate/intermediate.iml" filepath="$PROJECT_DIR$/intermediate/intermediate.iml" />
      <module fileurl="file://$PROJECT_DIR$/parser/parser.iml" filepath="$PROJECT_DIR$/parser/parser.iml" />
+      <module fileurl="file://$PROJECT_DIR$/virtualmachine/virtualmachine.iml" filepath="$PROJECT_DIR$/virtualmachine/virtualmachine.iml" />
    </modules>
  </component>
 </project>
@@ -3,4 +3,4 @@
  <component name="VcsDirectoryMappings">
    <mapping directory="$PROJECT_DIR$" vcs="Git" />
  </component>
-</project>
+</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
@@ -1,11 +0,0 @@
-language: java
-sudo: false
-# jdk: openjdk8
-# dist: xenial
-
-before_install:
-  - chmod +x ./gradlew
-
-script:
-  - ./gradlew test
-
@@ -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

@@ -1,5 +1,3 @@
-[![saythanks](https://img.shields.io/badge/say-thanks-ff69b4.svg)](https://saythanks.io/to/irmen)
-[![Build Status](https://travis-ci.org/irmen/prog8.svg?branch=master)](https://travis-ci.org/irmen/prog8)
 [![Documentation](https://readthedocs.org/projects/prog8/badge/?version=latest)](https://prog8.readthedocs.io/)

 Prog8 - Structured Programming Language for 8-bit 6502/65c02 microprocessors
@@ -7,9 +5,6 @@ Prog8 - Structured Programming Language for 8-bit 6502/65c02 microprocessors

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

-*Software license: GNU GPL 3.0, see file LICENSE*
-
-
 This is a structured programming language for the 8-bit 6502/6510/65c02 microprocessor from the late 1970's and 1980's
 as used in many home computers from that era. It is a medium to low level programming language,
 which aims to provide many conveniences over raw assembly code (even when using a macro assembler).
@@ -19,25 +14,53 @@ 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?
 ------------------------

- big reduction of source code length over raw assembly
+- reduction of source code length over raw assembly
+- fast execution speed due to compilation to native assembly code. It's possible to write certain raster interrupt 'demoscene' effects purely in Prog8.
 - modularity, symbol scoping, subroutines
 - various data types other than just bytes (16-bit words, floats, strings)
- automatic variable allocations, automatic string and array variables and string sharing
- subroutines with an input- and output parameter signature
- no stack frame allocations because parameters and local variables are automatically allocated statically
- constant folding in expressions and other high-level program optimizations
+- 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
- floating point operations  (requires the C64 Basic ROM routines for this)
- 'when' statement to provide a concise jump table alternative to if/elseif chains
- many built-in functions such as ``sin``, ``cos``, ``rnd``, ``abs``, ``min``, ``max``, ``sqrt``, ``msb``, ``rol``, ``ror``, ``swap``, ``memset``, ``memcopy``, ``sort`` and ``reverse``
- structs to group together sets of variables and manipulate them at once
+- ``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
- fast execution speed due to compilation to native assembly code
 - 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:*

@@ -46,11 +69,14 @@ What does Prog8 provide?
 - breakpoints, that let the Vice emulator drop into the monitor if execution hits them
 - source code labels automatically loaded in Vice emulator so it can show them in disassembly

-*Two supported compiler targets* (contributions to improve these or to add support for other machines are welcome!):
+*Multiple supported compiler targets* (contributions to improve these or to add support for other machines are welcome!):

- "c64": Commodore-64  (6510 CPU = almost a 6502), the main target.
- "cx16": [CommanderX16](https://www.commanderx16.com)  (65c02 CPU) .
- If you only use standard kernel and prog8 library routines, it is possible to compile the *exact same program* for both machines (just change the compiler target flag)!
+- "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)



@@ -67,7 +93,12 @@ IntelliJ IDEA with the Kotlin plugin).

 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 the [x16emu emulator](https://github.com/commanderx16/x16-emulator) for the CommanderX16 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
@@ -84,9 +115,7 @@ This code calculates prime numbers using the Sieve of Eratosthenes algorithm::
        ubyte candidate_prime = 2       ; is increased in the loop
    
        sub start() {
-            ; clear the sieve, to reset starting situation on subsequent runs
-            memset(sieve, 256, false)   
-            ; calculate primes
+            sys.memset(sieve, 256, false)   ; clear the sieve
            txt.print("prime numbers up to 255:\n\n")
            ubyte amount=0
            repeat {
@@ -97,17 +126,17 @@ This code calculates prime numbers using the Sieve of Eratosthenes algorithm::
                txt.print(", ")
                amount++
            }
-            txt.chrout('\n')
+            txt.nl()
            txt.print("number of primes (expected 54): ")
            txt.print_ub(amount)
-            txt.chrout('\n')
+            txt.nl()
        }
    
        sub find_next_prime() -> ubyte {
            while sieve[candidate_prime] {
                candidate_prime++
                if candidate_prime==0
-                    return 0        ; we wrapped; no more primes available in the sieve
+                    return 0        ; we wrapped; no more primes
            }
    
            ; found next one, mark the multiples and return it.
@@ -124,6 +153,7 @@ This code calculates prime numbers using the Sieve of Eratosthenes algorithm::



+
 when compiled an ran on a C-64 you'll get:

 ![c64 screen](docs/source/_static/primes_example.png)
@@ -140,7 +170,8 @@ If you want to play a video game, a fully working Tetris clone is included in th

 ![tehtriz_screen](docs/source/_static/tehtriz.png)

-The CommanderX16 compiler target is quite capable already too, here's a well known space ship 
-animated in 3D with hidden line removal, in the CommanderX16 emulator:
+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 "$kotlinVersion" apply false
+}
+
+allprojects {
+    repositories {
+        mavenLocal()
+        mavenCentral()
+    }
+}
@@ -0,0 +1,43 @@
+
+plugins {
+    id 'java'
+    id 'application'
+    id "org.jetbrains.kotlin.jvm"
+}
+
+java {
+    toolchain {
+        languageVersion = JavaLanguageVersion.of(javaVersion)
+    }
+}
+
+compileKotlin {
+    kotlinOptions {
+        jvmTarget = javaVersion
+    }
+}
+
+compileTestKotlin {
+    kotlinOptions {
+        jvmTarget = javaVersion
+    }
+}
+
+dependencies {
+    // should have no dependencies to other modules
+    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8"
+    implementation "com.michael-bull.kotlin-result:kotlin-result-jvm:1.1.18"
+}
+
+sourceSets {
+    main {
+        java {
+            srcDirs = ["${project.projectDir}/src"]
+        }
+        resources {
+            srcDirs = ["${project.projectDir}/res"]
+        }
+    }
+}
+
+// note: there are no unit tests in this module!
@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<module type="JAVA_MODULE" version="4">
+  <component name="NewModuleRootManager" inherit-compiler-output="true">
+    <exclude-output />
+    <content url="file://$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 +1,259 @@
+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)
+            require(onetimeInitializationNumericValue!=0.0) { "zero as init value should just remain uninitialized"}
+        }
+        if(onetimeInitializationArrayValue!=null) {
+            require(dt in ArrayDatatypes)
+            if(onetimeInitializationArrayValue.all { it.number!=null} ) {
+                require(onetimeInitializationArrayValue.any { it.number != 0.0 }) { "array of all zerors as init value should just remain uninitialized" }
+            }
+        }
+        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 +1,203 @@
+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 -> {
+                            val array = makeInitialArray(value)
+                            initialArray = if(array.all { it.number==0.0 }) null else array            // all 0 as init value -> just uninitialized
+                            initialString = null
+                            numElements = array.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 -> 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 +1,120 @@
+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 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 +1,304 @@
+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 -> other is PtAddressOf && other.type==type && other.identifier isSameAs identifier
+            is PtArrayIndexer -> other is PtArrayIndexer && other.type==type && other.variable isSameAs variable && other.index isSameAs index && 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.single() as PtIdentifier
+}
+
+
+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 +1,134 @@
+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:
+    "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),
+    "pokemon"   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),
+    "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("rol", "ror", "rol2", "ror2", "sort", "reverse")
@@ -0,0 +1,30 @@
+package prog8.code.core
+
+import java.nio.file.Path
+import kotlin.io.path.Path
+
+
+class CompilationOptions(val output: OutputType,
+                         val launcher: CbmPrgLauncherType,
+                         val zeropage: ZeropageType,
+                         val zpReserved: List<UIntRange>,
+                         val floats: Boolean,
+                         val noSysInit: Boolean,
+                         val compTarget: ICompilationTarget,
+                         // these are set later, based on command line arguments or options in the source code:
+                         var loadAddress: UInt,
+                         var 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 outputDir: Path = Path(""),
+                         var symbolDefs: Map<String, String> = emptyMap()
+) {
+    init {
+        compTarget.machine.initializeMemoryAreas(this)
+    }
+}
@@ -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 +1,188 @@
+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 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
+)
+
+
+
+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 +1,166 @@
+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 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 +1,56 @@
+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()
+    }
+
+    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 +1,77 @@
+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()
+    }
+
+    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 +1,96 @@
+package prog8.code.target.c64
+
+import prog8.code.core.*
+
+
+class C64Zeropage(options: CompilationOptions) : Zeropage(options) {
+
+    override val SCRATCH_B1 = 0x02u      // temp storage for a single byte
+    override val SCRATCH_REG = 0x03u     // temp storage for a register, must be B1+1
+    override val SCRATCH_W1 = 0xfbu      // temp storage 1 for a word  $fb+$fc
+    override val SCRATCH_W2 = 0xfdu      // temp storage 2 for a word  $fd+$fe
+
+
+    init {
+        if (options.floats && options.zeropage !in arrayOf(
+                ZeropageType.FLOATSAFE,
+                ZeropageType.BASICSAFE,
+                ZeropageType.DONTUSE
+            ))
+            throw InternalCompilerException("when floats are enabled, zero page type should be 'floatsafe' or 'basicsafe' or 'dontuse'")
+
+        if (options.zeropage == ZeropageType.FULL) {
+            free.addAll(0x02u..0xffu)
+            free.removeAll(setOf(SCRATCH_B1, SCRATCH_REG, SCRATCH_W1, SCRATCH_W1+1u, SCRATCH_W2, SCRATCH_W2+1u))
+            free.removeAll(setOf(0xa0u, 0xa1u, 0xa2u, 0x91u, 0xc0u, 0xc5u, 0xcbu, 0xf5u, 0xf6u))        // these are updated by IRQ
+        } else {
+            if (options.zeropage == ZeropageType.KERNALSAFE || options.zeropage == ZeropageType.FLOATSAFE) {
+                free.addAll(listOf(
+                        0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
+                        0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,
+                        0x20, 0x21, 0x22, 0x23, 0x24, 0x25,
+                        0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f, 0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46,
+                        0x47, 0x48, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f, 0x51, 0x52, 0x53,
+                        0x57, 0x58, 0x59, 0x5a, 0x5b, 0x5c, 0x5d, 0x5e, 0x5f, 0x60,
+                        0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68,
+                        0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f, 0x70, 0x71, 0x72,
+                        0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7a, 0x7b, 0x7c,
+                        0x7d, 0x7e, 0x7f, 0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89, 0x8a,
+                        0x8b, 0x8c, 0x8d, 0x8e, 0x8f, 0xff
+                        // 0x90-0xfa is 'kernal work storage area'
+                ).map{it.toUInt()})
+            }
+
+            if (options.zeropage == ZeropageType.FLOATSAFE) {
+                // remove the zeropage locations used for floating point operations from the free list
+                free.removeAll(listOf(
+                        0x03, 0x04, 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, 0xa5, 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()
+        }
+    }
+
+    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+$7f
+
+
+    init {
+        if (options.floats && options.zeropage !in arrayOf(
+                ZeropageType.FLOATSAFE,
+                ZeropageType.BASICSAFE,
+                ZeropageType.DONTUSE
+            ))
+            throw InternalCompilerException("when floats are enabled, zero page type should be 'floatsafe' or 'basicsafe' or 'dontuse'")
+
+        // the addresses 0x02 to 0x21 (inclusive) are taken for sixteen virtual 16-bit api registers.
+
+        synchronized(this) {
+            when (options.zeropage) {
+                ZeropageType.FULL -> {
+                    free.addAll(0x22u..0xffu)
+                }
+                ZeropageType.KERNALSAFE -> {
+                    free.addAll(0x22u..0x7fu)
+                    free.addAll(0xa9u..0xffu)
+                }
+                ZeropageType.FLOATSAFE -> {
+                    free.addAll(0x22u..0x7fu)
+                    free.addAll(0xd4u..0xffu)
+                }
+                ZeropageType.BASICSAFE -> {
+                    free.addAll(0x22u..0x7fu)
+                }
+                ZeropageType.DONTUSE -> {
+                    free.clear() // don't use zeropage at all
+                }
+            }
+
+            val distinctFree = free.distinct()
+            free.clear()
+            free.addAll(distinctFree)
+
+            removeReservedFromFreePool()
+
+            allocateCx16VirtualRegisters()
+        }
+    }
+
+    override fun allocateCx16VirtualRegisters() {
+        // Note: the 16 virtual registers R0-R15 are not regular allocated variables, they're *memory mapped* elsewhere to fixed addresses.
+        // However, to be able for the compiler to "see" them as zero page variables, we have to register them here as well.
+        // This is important because the compiler sometimes treats ZP variables more efficiently (for example if it's a pointer)
+        for(reg in 0..15) {
+            allocatedVariables["cx16.r${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 +1,58 @@
+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()
+    }
+
+    override fun allocateCx16VirtualRegisters() {
+        TODO("Not known if C128 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:5.6.2'
+}
+
+sourceSets {
+    main {
+        java {
+            srcDirs = ["${project.projectDir}/src"]
+        }
+        resources {
+            srcDirs = ["${project.projectDir}/res"]
+        }
+    }
+    test {
+        java {
+            srcDir "${project.projectDir}/test"
+        }
+    }
+}
+
+test {
+    // Enable JUnit 5 (Gradle 4.6+).
+    useJUnitPlatform()
+
+    // Always run tests, even when nothing changed.
+    dependsOn 'cleanTest'
+
+    // Show test results.
+    testLogging {
+        events "skipped", "failed"
+    }
+}
@@ -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 +1,511 @@
+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++
+    }
+
+    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
+}
@@ -0,0 +1,60 @@
+package prog8.codegen.cpu6502
+
+import prog8.code.ast.*
+import prog8.code.core.Cx16VirtualRegisters
+import prog8.code.core.RegisterOrPair
+import prog8.code.core.RegisterOrStatusflag
+
+
+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 (X last), except A,
+    //  4) CPU Carry status flag
+    //  5) the A register itself last   (so everything before it can use the accumulator without having to save its value)
+    val args = sub.parameters.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 (regsWithoutA, args4) = args3.partition { it.value.first.registerOrPair != RegisterOrPair.A }
+    val (regA, rest) = args4.partition { it.value.first.registerOrPair != null }
+
+    cx16regs.forEach { order += it.index }
+    pairedRegs.forEach { order += it.index }
+    regsWithoutA.forEach {
+        if(it.value.first.registerOrPair != RegisterOrPair.X)
+            order += it.index
+    }
+    regsWithoutA.firstOrNull { it.value.first.registerOrPair==RegisterOrPair.X } ?.let { order += it.index}
+    rest.forEach { order += it.index }
+    regA.forEach { order += it.index }
+    require(order.size==sub.parameters.size)
+    return order
+}
+
+fun asmsub6502ArgsHaveRegisterClobberRisk(
+    args: List<PtExpression>,
+    params: List<Pair<RegisterOrStatusflag, PtSubroutineParameter>>
+): Boolean {
+    fun isClobberRisk(expr: PtExpression): Boolean {
+        when (expr) {
+            is PtArrayIndexer -> {
+                return params.any {
+                    it.first.registerOrPair in listOf(RegisterOrPair.Y, RegisterOrPair.AY, RegisterOrPair.XY)
+                }
+            }
+            is PtBuiltinFunctionCall -> {
+                if (expr.name == "lsb" || expr.name == "msb")
+                    return isClobberRisk(expr.args[0])
+                if (expr.name == "mkword")
+                    return isClobberRisk(expr.args[0]) && isClobberRisk(expr.args[1])
+                return !expr.isSimple()
+            }
+            else -> return !expr.isSimple()
+        }
+    }
+
+    return args.size>1 && args.any { isClobberRisk(it) }
+}
@@ -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)
+    }
+}
@@ -1,45 +1,47 @@
-package prog8.compiler.target.c64.codegen
+package prog8.codegen.cpu6502

-import prog8.ast.Program
-import prog8.ast.base.ArrayElementTypes
-import prog8.ast.base.DataType
-import prog8.ast.base.RegisterOrPair
-import prog8.ast.expressions.IdentifierReference
-import prog8.ast.expressions.RangeExpr
-import prog8.ast.statements.ForLoop
-import prog8.compiler.AssemblyError
-import prog8.compiler.toHex
+import com.github.michaelbull.result.fold
+import prog8.code.ast.*
+import prog8.code.core.*
 import kotlin.math.absoluteValue

-internal class ForLoopsAsmGen(private val program: Program, private val asmgen: AsmGen) {
+internal class ForLoopsAsmGen(
+    private val asmgen: AsmGen6502Internal,
+    private val zeropage: Zeropage
+) {

-    internal fun translate(stmt: ForLoop) {
-        val iterableDt = stmt.iterable.inferType(program)
-        if(!iterableDt.isKnown)
-            throw AssemblyError("unknown dt")
+    internal fun translate(stmt: PtForLoop) {
+        val iterableDt = stmt.iterable.type
        when(stmt.iterable) {
-            is RangeExpr -> {
-                val range = (stmt.iterable as RangeExpr).toConstantIntegerRange()
+            is PtRange -> {
+                val range = (stmt.iterable as PtRange).toConstantIntegerRange()
                if(range==null) {
-                    translateForOverNonconstRange(stmt, iterableDt.typeOrElse(DataType.STRUCT), stmt.iterable as RangeExpr)
+                    translateForOverNonconstRange(stmt, iterableDt, stmt.iterable as PtRange)
                } else {
-                    translateForOverConstRange(stmt, iterableDt.typeOrElse(DataType.STRUCT), range)
+                    translateForOverConstRange(stmt, iterableDt, range)
                }
            }
-            is IdentifierReference -> {
-                translateForOverIterableVar(stmt, iterableDt.typeOrElse(DataType.STRUCT), stmt.iterable as IdentifierReference)
+            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: ForLoop, iterableDt: DataType, range: RangeExpr) {
+    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.constValue(program)!!.number.toInt()
+        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) {
@@ -48,29 +50,85 @@ internal class ForLoopsAsmGen(private val program: Program, private val asmgen:

                    val incdec = if(stepsize==1) "inc" else "dec"
                    // loop over byte range via loopvar
-                    val varname = asmgen.asmVariableName(stmt.loopVar)
-                    asmgen.assignExpressionToVariable(range.from, varname, ArrayElementTypes.getValue(iterableDt), null)
-                    asmgen.assignExpressionToVariable(range.to, "$modifiedLabel+1", ArrayElementTypes.getValue(iterableDt), null)
+                    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.body)
+                    asmgen.translate(stmt.statements)
                    asmgen.out("""
                        lda  $varname
 $modifiedLabel          cmp  #0         ; modified 
                        beq  $endLabel
-                        $incdec  $varname
-                        jmp  $loopLabel
-$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.loopVar)
-                    asmgen.assignExpressionToVariable(range.from, varname, ArrayElementTypes.getValue(iterableDt), null)
-                    asmgen.assignExpressionToVariable(range.to, "$modifiedLabel+1", ArrayElementTypes.getValue(iterableDt), null)
+                    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.body)
+                    asmgen.translate(stmt.statements)
                    if(stepsize>0) {
                        asmgen.out("""
                            lda  $varname
@@ -98,14 +156,15 @@ $modifiedLabel              cmp  #0     ; modified
                    // words, step 1 or -1

                    stepsize == 1 || stepsize == -1 -> {
-                        val varname = asmgen.asmVariableName(stmt.loopVar)
-                        assignLoopvar(stmt, range)
+                        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.body)
+                        asmgen.translate(stmt.statements)
                        asmgen.out("""
                lda  $varname+1
 $modifiedLabel  cmp  #0    ; modified 
@@ -117,30 +176,30 @@ $modifiedLabel2 cmp  #0    ; modified
                            asmgen.out("""
 +               inc  $varname
                bne  $loopLabel
-                inc  $varname+1
-                jmp  $loopLabel
-                            """)
+                inc  $varname+1""")
+                            asmgen.jmp(loopLabel)
                        } else {
                            asmgen.out("""
 +               lda  $varname
                bne  +
                dec  $varname+1
-+               dec  $varname
-                jmp  $loopLabel""")
+               dec  $varname""")
+                            asmgen.jmp(loopLabel)
                        }
                        asmgen.out(endLabel)
                    }
                    stepsize > 0 -> {

                        // (u)words, step >= 2
-                        val varname = asmgen.asmVariableName(stmt.loopVar)
-                        assignLoopvar(stmt, range)
+                        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.body)
+                        asmgen.translate(stmt.statements)

                        if (iterableDt == DataType.ARRAY_UW) {
                            asmgen.out("""
@@ -181,32 +240,16 @@ $endLabel""")
                    else -> {

                        // (u)words, step <= -2
-                        val varname = asmgen.asmVariableName(stmt.loopVar)
-                        assignLoopvar(stmt, range)
+                        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.body)
+                        asmgen.translate(stmt.statements)

-                        if(iterableDt==DataType.ARRAY_UW) {
-                            asmgen.out("""
-                lda  $varname
-                sec
-                sbc  #<${stepsize.absoluteValue}
-                sta  $varname
-                lda  $varname+1
-                sbc  #>${stepsize.absoluteValue}
-                sta  $varname+1
-$modifiedLabel  cmp  #0    ; modified                
-                bcc  $endLabel
-                bne  $loopLabel
-                lda  $varname
-$modifiedLabel2 cmp  #0    ; modified 
-                bcs  $loopLabel
-$endLabel""")
-                        } else {
                            asmgen.out("""
                lda  $varname
                sec
@@ -224,7 +267,6 @@ $modifiedLabel  sbc  #0    ; modified
                eor  #$80
 +               bpl  $loopLabel                
 $endLabel""")
-                        }
                    }
                }
            }
@@ -234,12 +276,68 @@ $endLabel""")
        asmgen.loopEndLabels.pop()
    }

-    private fun translateForOverIterableVar(stmt: ForLoop, iterableDt: DataType, ident: IdentifierReference) {
+    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 decl = ident.targetVarDecl(program.namespace)!!
+        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("""
@@ -249,8 +347,8 @@ $endLabel""")
                    sty  $loopLabel+2
 $loopLabel          lda  ${65535.toHex()}       ; modified
                    beq  $endLabel
-                    sta  ${asmgen.asmVariableName(stmt.loopVar)}""")
-                asmgen.translate(stmt.body)
+                    sta  ${asmgen.asmVariableName(stmt.variable)}""")
+                asmgen.translate(stmt.statements)
                asmgen.out("""
                    inc  $loopLabel+1
                    bne  $loopLabel
@@ -259,19 +357,18 @@ $loopLabel          lda  ${65535.toHex()}       ; modified
 $endLabel""")
            }
            DataType.ARRAY_UB, DataType.ARRAY_B -> {
-                val length = decl.arraysize!!.constIndex()!!
                val indexVar = asmgen.makeLabel("for_index")
                asmgen.out("""
                    ldy  #0
 $loopLabel          sty  $indexVar
                    lda  $iterableName,y
-                    sta  ${asmgen.asmVariableName(stmt.loopVar)}""")
-                asmgen.translate(stmt.body)
-                if(length<=255) {
+                    sta  ${asmgen.asmVariableName(stmt.variable)}""")
+                asmgen.translate(stmt.statements)
+                if(numElements!!<=255u) {
                    asmgen.out("""
                        ldy  $indexVar
                        iny
-                        cpy  #$length
+                        cpy  #$numElements
                        beq  $endLabel
                        bne  $loopLabel""")
                } else {
@@ -282,20 +379,22 @@ $loopLabel          sty  $indexVar
                        bne  $loopLabel
                        beq  $endLabel""")
                }
-                if(length>=16 && asmgen.zeropage.available() > 0) {
-                    // allocate index var on ZP
-                    val zpAddr = asmgen.zeropage.allocate(indexVar, DataType.UBYTE, stmt.position, asmgen.errors)
-                    asmgen.out("""$indexVar = $zpAddr  ; auto zp UBYTE""")
+                if(numElements>=16u) {
+                    // allocate index var on ZP if possible
+                    val result = zeropage.allocate(indexVar, DataType.UBYTE, null, stmt.position, asmgen.errors)
+                    result.fold(
+                        success = { (address, _, _)-> asmgen.out("""$indexVar = $address  ; auto zp UBYTE""") },
+                        failure = { asmgen.out("$indexVar    .byte  0") }
+                    )
                } else {
-                    asmgen.out("""
-$indexVar           .byte  0""")
+                    asmgen.out("$indexVar    .byte  0")
                }
                asmgen.out(endLabel)
            }
            DataType.ARRAY_W, DataType.ARRAY_UW -> {
-                val length = decl.arraysize!!.constIndex()!! * 2
+                val length = numElements!! * 2u
                val indexVar = asmgen.makeLabel("for_index")
-                val loopvarName = asmgen.asmVariableName(stmt.loopVar)
+                val loopvarName = asmgen.asmVariableName(stmt.variable)
                asmgen.out("""
                    ldy  #0
 $loopLabel          sty  $indexVar
@@ -303,8 +402,8 @@ $loopLabel          sty  $indexVar
                    sta  $loopvarName
                    lda  $iterableName+1,y
                    sta  $loopvarName+1""")
-                asmgen.translate(stmt.body)
-                if(length<=127) {
+                asmgen.translate(stmt.statements)
+                if(length<=127u) {
                    asmgen.out("""
                        ldy  $indexVar
                        iny
@@ -321,13 +420,54 @@ $loopLabel          sty  $indexVar
                        bne  $loopLabel
                        beq  $endLabel""")
                }
-                if(length>=16 && asmgen.zeropage.available() > 0) {
-                    // allocate index var on ZP
-                    val zpAddr = asmgen.zeropage.allocate(indexVar, DataType.UBYTE, stmt.position, asmgen.errors)
-                    asmgen.out("""$indexVar = $zpAddr  ; auto zp UBYTE""")
+                if(length>=16u) {
+                    // allocate index var on ZP if possible
+                    val result = zeropage.allocate(indexVar, DataType.UBYTE, null, stmt.position, asmgen.errors)
+                    result.fold(
+                        success = { (address,_,_)-> asmgen.out("""$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  $loopvarName+1""")
+                asmgen.translate(stmt.statements)
+                if(numElements<=255u) {
                    asmgen.out("""
-$indexVar           .byte  0""")
+                        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)
            }
@@ -339,7 +479,7 @@ $indexVar           .byte  0""")
        asmgen.loopEndLabels.pop()
    }

-    private fun translateForOverConstRange(stmt: ForLoop, iterableDt: DataType, range: IntProgression) {
+    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) {
@@ -358,18 +498,18 @@ $indexVar           .byte  0""")
        when(iterableDt) {
            DataType.ARRAY_B, DataType.ARRAY_UB -> {
                // loop over byte range via loopvar, step >= 2 or <= -2
-                val varname = asmgen.asmVariableName(stmt.loopVar)
+                val varname = asmgen.asmVariableName(stmt.variable)
                asmgen.out("""
                            lda  #${range.first}
                            sta  $varname
 $loopLabel""")
-                asmgen.translate(stmt.body)
+                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) {
+                        if(range.last==255 || range.last==254) {
                            asmgen.out("""
                                inc  $varname
                                beq  $endLabel
@@ -377,34 +517,34 @@ $loopLabel""")
                                bne  $loopLabel""")
                        } else {
                            asmgen.out("""
+                                inc  $varname
+                                inc  $varname
                                lda  $varname
-                                cmp  #${range.last}
-                                beq  $endLabel
-                                inc  $varname
-                                inc  $varname
-                                jmp  $loopLabel""")
+                                cmp  #${range.last+2}
+                                bne  $loopLabel""")
                        }
                    }
                    -2 -> {
                        when (range.last) {
-                            0 -> asmgen.out("""
-                                lda  $varname
-                                beq  $endLabel
-                                dec  $varname
-                                dec  $varname
-                                jmp  $loopLabel""")
+                            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""")
+                                    dec  $varname
+                                    beq  $endLabel
+                                    dec  $varname
+                                    bne  $loopLabel""")
                            else -> asmgen.out("""
-                                lda  $varname
-                                cmp  #${range.last}
-                                beq  $endLabel
-                                dec  $varname
-                                dec  $varname
-                                jmp  $loopLabel""")
+                                    dec  $varname
+                                    dec  $varname
+                                    lda  $varname
+                                    cmp  #${range.last-2}
+                                    bne  $loopLabel""")
                        }
                    }
                    else -> {
@@ -415,15 +555,15 @@ $loopLabel""")
                            beq  $endLabel
                            clc
                            adc  #${range.step}
-                            sta  $varname
-                            jmp  $loopLabel""")
+                            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.loopVar)
+                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")
@@ -437,7 +577,7 @@ $loopLabel""")
                            sta  $varname
                            sty  $varname+1
 $loopLabel""")
-                        asmgen.translate(stmt.body)
+                        asmgen.translate(stmt.statements)
                        asmgen.out("""
                            lda  $varname
                            cmp  #<${range.last}
@@ -452,9 +592,9 @@ $loopLabel""")
                            sta  $varname
                            lda  $varname+1
                            adc  #>${range.step}
-                            sta  $varname+1
-                            jmp  $loopLabel
-$endLabel""")
+                            sta  $varname+1""")
+                        asmgen.jmp(loopLabel)
+                        asmgen.out(endLabel)
                    }
                }
            }
@@ -463,16 +603,16 @@ $endLabel""")
        asmgen.loopEndLabels.pop()
    }

-    private fun translateForSimpleByteRangeAsc(stmt: ForLoop, range: IntProgression) {
+    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.loopVar)
+        val varname = asmgen.asmVariableName(stmt.variable)
        asmgen.out("""
                lda  #${range.first}
                sta  $varname
 $loopLabel""")
-        asmgen.translate(stmt.body)
+        asmgen.translate(stmt.statements)
        if (range.last == 255) {
            asmgen.out("""
                inc  $varname
@@ -480,111 +620,110 @@ $loopLabel""")
 $endLabel""")
        } else {
            asmgen.out("""
-                lda  $varname
-                cmp  #${range.last}
-                beq  $endLabel
                inc  $varname
-                jmp  $loopLabel
+                lda  $varname
+                cmp  #${range.last+1}
+                bne  $loopLabel
 $endLabel""")
        }
        asmgen.loopEndLabels.pop()
    }

-    private fun translateForSimpleByteRangeDesc(stmt: ForLoop, range: IntProgression) {
+    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.loopVar)
+        val varname = asmgen.asmVariableName(stmt.variable)
        asmgen.out("""
                    lda  #${range.first}
                    sta  $varname
 $loopLabel""")
-        asmgen.translate(stmt.body)
+        asmgen.translate(stmt.statements)
        when (range.last) {
            0 -> {
                asmgen.out("""
                    lda  $varname
                    beq  $endLabel
-                    dec  $varname
-                    jmp  $loopLabel
-$endLabel""")
+                    dec  $varname""")
+                asmgen.jmp(loopLabel)
+                asmgen.out(endLabel)
            }
            1 -> {
                asmgen.out("""
                    dec  $varname
-                    jmp  $loopLabel
+                    bne  $loopLabel
 $endLabel""")
            }
            else -> {
                asmgen.out("""
-                    lda  $varname
-                    cmp  #${range.last}
-                    beq  $endLabel
                    dec  $varname
-                    jmp  $loopLabel
+                    lda  $varname
+                    cmp  #${range.last-1}
+                    bne  $loopLabel
 $endLabel""")
            }
        }
        asmgen.loopEndLabels.pop()
    }

-    private fun translateForSimpleWordRangeAsc(stmt: ForLoop, range: IntProgression) {
+    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.loopVar)
+        val varname = asmgen.asmVariableName(stmt.variable)
        asmgen.out("""
            lda  #<${range.first}
            ldy  #>${range.first}
            sta  $varname
            sty  $varname+1
 $loopLabel""")
-        asmgen.translate(stmt.body)
+        asmgen.translate(stmt.statements)
        asmgen.out("""
            lda  $varname
            cmp  #<${range.last}
            bne  +
            lda  $varname+1
            cmp  #>${range.last}
-            bne  +
            beq  $endLabel
 +           inc  $varname
            bne  $loopLabel
-            inc  $varname+1
-            jmp  $loopLabel
-$endLabel""")
+            inc  $varname+1""")
+        asmgen.jmp(loopLabel)
+        asmgen.out(endLabel)
        asmgen.loopEndLabels.pop()
    }

-    private fun translateForSimpleWordRangeDesc(stmt: ForLoop, range: IntProgression) {
+    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.loopVar)
+        val varname = asmgen.asmVariableName(stmt.variable)
        asmgen.out("""
            lda  #<${range.first}
            ldy  #>${range.first}
            sta  $varname
            sty  $varname+1
 $loopLabel""")
-        asmgen.translate(stmt.body)
+        asmgen.translate(stmt.statements)
        asmgen.out("""
            lda  $varname
            cmp  #<${range.last}
            bne  +
            lda  $varname+1
            cmp  #>${range.last}
-            bne  +
            beq  $endLabel
 +           lda  $varname
            bne  +
            dec  $varname+1
-+           dec  $varname
-            jmp  $loopLabel
-$endLabel""")
+           dec  $varname""")
+        asmgen.jmp(loopLabel)
+        asmgen.out(endLabel)
        asmgen.loopEndLabels.pop()
    }

-    private fun assignLoopvar(stmt: ForLoop, range: RangeExpr) =
-        asmgen.assignExpressionToVariable(range.from, asmgen.asmVariableName(stmt.loopVar), stmt.loopVarDt(program).typeOrElse(DataType.STRUCT), stmt.definingSubroutine())
+    private fun assignLoopvarWord(stmt: PtForLoop, range: PtRange) =
+        asmgen.assignExpressionToVariable(
+            range.from,
+            asmgen.asmVariableName(stmt.variable),
+            stmt.variable.type)
 }
@@ -0,0 +1,210 @@
+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 argumentsViaRegisters(sub: PtAsmSub, call: PtFunctionCall) {
+        if(sub.parameters.size==1) {
+            argumentViaRegister(sub, IndexedValue(0, sub.parameters.single().second), call.args[0])
+        } else {
+            if(asmsub6502ArgsHaveRegisterClobberRisk(call.args, sub.parameters)) {
+                registerArgsViaCpuStackEvaluation(call, sub)
+            } else {
+                asmsub6502ArgsEvalOrder(sub).forEach {
+                    val param = sub.parameters[it]
+                    val arg = call.args[it]
+                    argumentViaRegister(sub, IndexedValue(it, param.second), arg)
+                }
+            }
+        }
+    }
+
+    private fun registerArgsViaCpuStackEvaluation(call: PtFunctionCall, callee: PtAsmSub) {
+        // this is called when one or more of the arguments are 'complex' and
+        // cannot be assigned to a register easily or risk clobbering other registers.
+
+        if(callee.parameters.isEmpty())
+            return
+
+        // use the cpu hardware stack as intermediate storage for the arguments.
+        val argOrder = asmsub6502ArgsEvalOrder(callee)
+        argOrder.reversed().forEach {
+            asmgen.pushCpuStack(callee.parameters[it].second.type, call.args[it])
+        }
+        argOrder.forEach {
+            val param = callee.parameters[it]
+            asmgen.popCpuStack(callee, param.second, param.first)
+        }
+    }
+
+    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) {
+        // 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)
+                        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")
+        }
+        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)
+            }
+        }
+    }
+
+    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 +1,747 @@
+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
+            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 +1,265 @@
+package prog8.codegen.cpu6502.assignment
+
+import prog8.code.ast.PtBinaryExpression
+import prog8.code.core.*
+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)
+                    TODO("words operands comparison -> byte")
+                }
+                if (expr.left.type==DataType.FLOAT && expr.right.type==DataType.FLOAT) {
+                    require(expr.operator in ComparisonOperators)
+                    return assignFloatBinExpr(expr, assign)
+                }
+                TODO("weird expr operand types")
+            }
+            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) {
+            "+" -> {
+                asmgen.assignExpressionToRegister(expr.left, RegisterOrPair.FAC1, true)
+                if(!expr.right.isSimple()) asmgen.pushFAC1()
+                asmgen.assignExpressionToRegister(expr.right, RegisterOrPair.FAC2, true)
+                if(!expr.right.isSimple()) asmgen.popFAC1()
+                asmgen.out("  jsr  floats.FADDT")
+                asmgen.assignRegister(RegisterOrPair.FAC1, assign.target)
+                return true
+            }
+            "-" -> {
+                asmgen.assignExpressionToRegister(expr.right, RegisterOrPair.FAC1, true)
+                if(!expr.left.isSimple()) asmgen.pushFAC1()
+                asmgen.assignExpressionToRegister(expr.left, RegisterOrPair.FAC2, true)
+                if(!expr.left.isSimple()) asmgen.popFAC1()
+                asmgen.out("  jsr  floats.FSUBT")
+                asmgen.assignRegister(RegisterOrPair.FAC1, assign.target)
+                return true
+            }
+            "*" -> {
+                asmgen.assignExpressionToRegister(expr.left, RegisterOrPair.FAC1, true)
+                if(!expr.right.isSimple()) asmgen.pushFAC1()
+                asmgen.assignExpressionToRegister(expr.right, RegisterOrPair.FAC2, true)
+                if(!expr.right.isSimple()) asmgen.popFAC1()
+                asmgen.out("  jsr  floats.FMULTT")
+                asmgen.assignRegister(RegisterOrPair.FAC1, assign.target)
+                return true
+            }
+            "/" -> {
+                asmgen.assignExpressionToRegister(expr.right, RegisterOrPair.FAC1, true)
+                if(!expr.left.isSimple()) asmgen.pushFAC1()
+                asmgen.assignExpressionToRegister(expr.left, RegisterOrPair.FAC2, true)
+                if(!expr.left.isSimple()) asmgen.popFAC1()
+                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 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 +1,128 @@
+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(),
+            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, 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, 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 {
+            srcDirs = ["${project.projectDir}/src"]
+        }
+        resources {
+            srcDirs = ["${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>