fix bug where non-inlined asmsub didn't always get a proper RTS, causing program crash

was caused by a change in 7.8; 8ae3bad6f7 "fix rts in empty asmsub"

.gitignore

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

.idea/codeInsightSettings.xml

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

.idea/codeStyles/Project.xml

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

.idea/codeStyles/codeStyleConfig.xml

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

.idea/compiler.xml

@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="CompilerConfiguration">
+    <option name="BUILD_PROCESS_HEAP_SIZE" value="1200" />
+    <bytecodeTargetLevel target="11" />
+  </component>
+</project>

.idea/inspectionProfiles/Project_Default.xml

@@ -3,14 +3,12 @@
     <option name="myName" value="Project Default" />
     <inspection_tool class="DuplicatedCode" enabled="true" level="WEAK WARNING" enabled_by_default="true">
       <Languages>
-        <language minSize="100" isEnabled="false" name="JavaScript" />
-        <language isEnabled="false" name="Groovy" />
-        <language isEnabled="false" name="Style Sheets" />
         <language minSize="70" name="Kotlin" />
-        <language isEnabled="false" name="TypeScript" />
-        <language isEnabled="false" name="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" />

.idea/kotlinc.xml

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

.idea/libraries/antlr_4_7_2_complete.xml

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

.idea/libraries/antlr_4_8_complete.xml

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

.idea/libraries/antlr_antlr4.xml

@@ -0,0 +1,19 @@
+<component name="libraryTable">
+  <library name="antlr.antlr4" type="repository">
+    <properties maven-id="org.antlr:antlr4:4.9.2">
+      <exclude>
+        <dependency maven-id="com.ibm.icu:icu4j" />
+      </exclude>
+    </properties>
+    <CLASSES>
+      <root url="jar://$MAVEN_REPOSITORY$/org/antlr/antlr4/4.9.2/antlr4-4.9.2.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/antlr/antlr4-runtime/4.9.2/antlr4-runtime-4.9.2.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/antlr/antlr-runtime/3.5.2/antlr-runtime-3.5.2.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/antlr/ST4/4.3/ST4-4.3.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/abego/treelayout/org.abego.treelayout.core/1.0.3/org.abego.treelayout.core-1.0.3.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/glassfish/javax.json/1.0.4/javax.json-1.0.4.jar!/" />
+    </CLASSES>
+    <JAVADOC />
+    <SOURCES />
+  </library>
+</component>

.idea/libraries/antlr_runtime_4_7_2.xml

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

.idea/libraries/antlr_runtime_4_8.xml

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

.idea/libraries/github_hypfvieh_dbus_java.xml

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

.idea/libraries/glassfish_javax_json.xml

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

.idea/libraries/io_kotest_assertions_core_jvm.xml

@@ -0,0 +1,22 @@
+<component name="libraryTable">
+  <library name="io.kotest.assertions.core.jvm" type="repository">
+    <properties maven-id="io.kotest:kotest-assertions-core-jvm:4.6.3" />
+    <CLASSES>
+      <root url="jar://$MAVEN_REPOSITORY$/io/kotest/kotest-assertions-core-jvm/4.6.3/kotest-assertions-core-jvm-4.6.3.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/kotlin/kotlin-stdlib-jdk8/1.5.0/kotlin-stdlib-jdk8-1.5.0.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/kotlin/kotlin-stdlib/1.5.0/kotlin-stdlib-1.5.0.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-jdk7/1.5.0/kotlin-stdlib-jdk7-1.5.0.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/io/kotest/kotest-assertions-shared-jvm/4.6.3/kotest-assertions-shared-jvm-4.6.3.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/io/github/java-diff-utils/java-diff-utils/4.9/java-diff-utils-4.9.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/kotlinx/kotlinx-coroutines-jdk8/1.5.0/kotlinx-coroutines-jdk8-1.5.0.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/kotlin/kotlin-reflect/1.5.0/kotlin-reflect-1.5.0.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/kotlinx/kotlinx-coroutines-core-jvm/1.5.0/kotlinx-coroutines-core-jvm-1.5.0.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/kotlin/kotlin-stdlib-common/1.5.0/kotlin-stdlib-common-1.5.0.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/io/kotest/kotest-common-jvm/4.6.3/kotest-common-jvm-4.6.3.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/io/kotest/kotest-assertions-api-jvm/4.6.3/kotest-assertions-api-jvm-4.6.3.jar!/" />
+    </CLASSES>
+    <JAVADOC />
+    <SOURCES />
+  </library>
+</component>

.idea/libraries/io_kotest_property_jvm.xml

@@ -0,0 +1,24 @@
+<component name="libraryTable">
+  <library name="io.kotest.property.jvm" type="repository">
+    <properties maven-id="io.kotest:kotest-property-jvm:4.6.3" />
+    <CLASSES>
+      <root url="jar://$MAVEN_REPOSITORY$/io/kotest/kotest-property-jvm/4.6.3/kotest-property-jvm-4.6.3.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/kotlin/kotlin-stdlib-jdk8/1.5.0/kotlin-stdlib-jdk8-1.5.0.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/kotlin/kotlin-stdlib/1.5.0/kotlin-stdlib-1.5.0.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-jdk7/1.5.0/kotlin-stdlib-jdk7-1.5.0.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/io/kotest/kotest-common-jvm/4.6.3/kotest-common-jvm-4.6.3.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/io/kotest/kotest-assertions-shared-jvm/4.6.3/kotest-assertions-shared-jvm-4.6.3.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/io/kotest/kotest-assertions-api-jvm/4.6.3/kotest-assertions-api-jvm-4.6.3.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/kotlinx/kotlinx-coroutines-jdk8/1.5.0/kotlinx-coroutines-jdk8-1.5.0.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/io/github/java-diff-utils/java-diff-utils/4.9/java-diff-utils-4.9.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/com/github/mifmif/generex/1.0.2/generex-1.0.2.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/dk/brics/automaton/automaton/1.11-8/automaton-1.11-8.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/kotlin/kotlin-reflect/1.5.0/kotlin-reflect-1.5.0.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/kotlinx/kotlinx-coroutines-core-jvm/1.5.0/kotlinx-coroutines-core-jvm-1.5.0.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/kotlin/kotlin-stdlib-common/1.5.0/kotlin-stdlib-common-1.5.0.jar!/" />
+    </CLASSES>
+    <JAVADOC />
+    <SOURCES />
+  </library>
+</component>

.idea/libraries/io_kotest_runner_junit5_jvm.xml

@@ -0,0 +1,56 @@
+<component name="libraryTable">
+  <library name="io.kotest.runner.junit5.jvm" type="repository">
+    <properties maven-id="io.kotest:kotest-runner-junit5-jvm:4.6.3" />
+    <CLASSES>
+      <root url="jar://$MAVEN_REPOSITORY$/io/kotest/kotest-runner-junit5-jvm/4.6.3/kotest-runner-junit5-jvm-4.6.3.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/io/kotest/kotest-framework-api-jvm/4.6.3/kotest-framework-api-jvm-4.6.3.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/io/kotest/kotest-assertions-shared-jvm/4.6.3/kotest-assertions-shared-jvm-4.6.3.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/io/github/java-diff-utils/java-diff-utils/4.9/java-diff-utils-4.9.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/io/kotest/kotest-common-jvm/4.6.3/kotest-common-jvm-4.6.3.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/io/kotest/kotest-framework-engine-jvm/4.6.3/kotest-framework-engine-jvm-4.6.3.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/io/github/classgraph/classgraph/4.8.105/classgraph-4.8.105.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/jetbrains/kotlin/kotlin-script-util/1.5.0/kotlin-script-util-1.5.0.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/intellij/deps/trove4j/1.0.20181211/trove4j-1.0.20181211.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/kotlin/kotlin-daemon-client/1.5.0/kotlin-daemon-client-1.5.0.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/kotlinx/kotlinx-coroutines-core/1.3.8/kotlinx-coroutines-core-1.3.8.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/kotlin/kotlin-scripting-jvm/1.5.0/kotlin-scripting-jvm-1.5.0.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/kotlin/kotlin-scripting-common/1.5.0/kotlin-scripting-common-1.5.0.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/opentest4j/opentest4j/1.2.0/opentest4j-1.2.0.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/io/kotest/kotest-framework-discovery-jvm/4.6.3/kotest-framework-discovery-jvm-4.6.3.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/io/kotest/kotest-assertions-core-jvm/4.6.3/kotest-assertions-core-jvm-4.6.3.jar!/" />
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+      <root url="jar://$MAVEN_REPOSITORY$/io/kotest/kotest-assertions-api-jvm/4.6.3/kotest-assertions-api-jvm-4.6.3.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/io/kotest/kotest-extensions-jvm/4.6.3/kotest-extensions-jvm-4.6.3.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/commons-io/commons-io/2.6/commons-io-2.6.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/io/mockk/mockk/1.9.3/mockk-1.9.3.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/io/mockk/mockk-common/1.9.3/mockk-common-1.9.3.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/io/mockk/mockk-dsl/1.9.3/mockk-dsl-1.9.3.jar!/" />
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+      <root url="jar://$MAVEN_REPOSITORY$/io/mockk/mockk-agent-jvm/1.9.3/mockk-agent-jvm-1.9.3.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/io/mockk/mockk-agent-api/1.9.3/mockk-agent-api-1.9.3.jar!/" />
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+      <root url="jar://$MAVEN_REPOSITORY$/org/objenesis/objenesis/3.0.1/objenesis-3.0.1.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/net/bytebuddy/byte-buddy/1.9.10/byte-buddy-1.9.10.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/net/bytebuddy/byte-buddy-agent/1.9.10/byte-buddy-agent-1.9.10.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/io/kotest/kotest-framework-concurrency-jvm/4.6.3/kotest-framework-concurrency-jvm-4.6.3.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/kotlinx/kotlinx-coroutines-core-jvm/1.5.0/kotlinx-coroutines-core-jvm-1.5.0.jar!/" />
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+      <root url="jar://$MAVEN_REPOSITORY$/org/apiguardian/apiguardian-api/1.1.0/apiguardian-api-1.1.0.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/junit/platform/junit-platform-commons/1.6.2/junit-platform-commons-1.6.2.jar!/" />
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+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/kotlin/kotlin-stdlib/1.5.0/kotlin-stdlib-1.5.0.jar!/" />
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+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/kotlin/kotlin-stdlib-jdk7/1.5.0/kotlin-stdlib-jdk7-1.5.0.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/kotlin/kotlin-script-runtime/1.5.0/kotlin-script-runtime-1.5.0.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/kotlin/kotlin-reflect/1.5.0/kotlin-reflect-1.5.0.jar!/" />
+    </CLASSES>
+    <JAVADOC />
+    <SOURCES />
+  </library>
+</component>

.idea/libraries/jetbrains_kotlinx_cli_jvm.xml

@@ -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:0.3.3" />
+    <CLASSES>
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/kotlinx/kotlinx-cli-jvm/0.3.3/kotlinx-cli-jvm-0.3.3.jar!/" />
+    </CLASSES>
+    <JAVADOC />
+    <SOURCES />
+  </library>
+</component>

.idea/libraries/kotlinx_cli_jvm_0_1_0_dev_5.xml

@@ -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>

.idea/libraries/michael_bull_kotlin_result_jvm.xml

@@ -0,0 +1,15 @@
+<component name="libraryTable">
+  <library name="michael.bull.kotlin.result.jvm" type="repository">
+    <properties maven-id="com.michael-bull.kotlin-result:kotlin-result-jvm:1.1.12" />
+    <CLASSES>
+      <root url="jar://$MAVEN_REPOSITORY$/com/michael-bull/kotlin-result/kotlin-result-jvm/1.1.12/kotlin-result-jvm-1.1.12.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/kotlin/kotlin-stdlib-jdk8/1.5.10/kotlin-stdlib-jdk8-1.5.10.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/kotlin/kotlin-stdlib/1.5.10/kotlin-stdlib-1.5.10.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-jdk7/1.5.10/kotlin-stdlib-jdk7-1.5.10.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/jetbrains/kotlin/kotlin-stdlib-common/1.5.10/kotlin-stdlib-common-1.5.10.jar!/" />
+    </CLASSES>
+    <JAVADOC />
+    <SOURCES />
+  </library>
+</component>

.idea/libraries/slf4j_simple.xml

@@ -0,0 +1,11 @@
+<component name="libraryTable">
+  <library name="slf4j.simple" type="repository">
+    <properties maven-id="org.slf4j:slf4j-simple:1.7.30" />
+    <CLASSES>
+      <root url="jar://$MAVEN_REPOSITORY$/org/slf4j/slf4j-simple/1.7.30/slf4j-simple-1.7.30.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/slf4j/slf4j-api/1.7.30/slf4j-api-1.7.30.jar!/" />
+    </CLASSES>
+    <JAVADOC />
+    <SOURCES />
+  </library>
+</component>

.idea/libraries/takes.xml

@@ -0,0 +1,13 @@
+<component name="libraryTable">
+  <library name="takes" type="repository">
+    <properties maven-id="org.takes:takes:1.19" />
+    <CLASSES>
+      <root url="jar://$MAVEN_REPOSITORY$/org/takes/takes/1.19/takes-1.19.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/cactoos/cactoos/0.42/cactoos-0.42.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/apache/commons/commons-text/1.4/commons-text-1.4.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/apache/commons/commons-lang3/3.7/commons-lang3-3.7.jar!/" />
+    </CLASSES>
+    <JAVADOC />
+    <SOURCES />
+  </library>
+</component>

.idea/libraries/unittest_libs.xml

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

.idea/misc.xml

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

.idea/modules.xml

@@ -2,9 +2,17 @@
 <project version="4">
   <component name="ProjectModuleManager">
     <modules>
+      <module fileurl="file://$PROJECT_DIR$/codeGenCpu6502/codeGenCpu6502.iml" filepath="$PROJECT_DIR$/codeGenCpu6502/codeGenCpu6502.iml" />
+      <module fileurl="file://$PROJECT_DIR$/codeGenExperimental6502/codeGenExperimental6502.iml" filepath="$PROJECT_DIR$/codeGenExperimental6502/codeGenExperimental6502.iml" />
+      <module fileurl="file://$PROJECT_DIR$/codeGenTargets/codeGenTargets.iml" filepath="$PROJECT_DIR$/codeGenTargets/codeGenTargets.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://$PROJECT_DIR$/compilerInterfaces/compilerInterfaces.iml" filepath="$PROJECT_DIR$/compilerInterfaces/compilerInterfaces.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://$PROJECT_DIR$/parser/parser.iml" filepath="$PROJECT_DIR$/parser/parser.iml" />
     </modules>
   </component>

.readthedocs.yaml

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

.travis.yml

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

CompilerDevelopment.md

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

LICENSE

@@ -1,3 +1,10 @@
+
+This sofware license is for Prog8 the compiler + associated libraries.
+The software generated by running the compiler is excluded from this.
+
+
+
+
                     GNU GENERAL PUBLIC LICENSE
                        Version 3, 29 June 2007
 

README.md

@@ -1,62 +1,81 @@
-[![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 6502/6510 microprocessors
-===========================================================================
+Prog8 - Structured Programming Language for 8-bit 6502/65c02 microprocessors
+============================================================================
 
 *Written by Irmen de Jong (irmen@razorvine.net)*
 
-*Software license: GNU GPL 3.0, see file LICENSE*
-
-
-This is a structured programming language for the 8-bit 6502/6510 microprocessor from the late 1970's and 1980's
+This is a structured programming language for the 8-bit 6502/6510/65c02 microprocessor from the late 1970's and 1980's
 as used in many home computers from that era. It is a medium to low level programming language,
-which aims to provide many conveniences over raw assembly code (even when using a macro assembler):
+which aims to provide many conveniences over raw assembly code (even when using a macro assembler).
 
-- reduction of source code length
+Documentation
+-------------
+Full documentation (syntax reference, how to use the language and the compiler, etc.) can be found at:
+https://prog8.readthedocs.io/
+
+Software license
+----------------
+GNU GPL 3.0, see file LICENSE
+
+- prog8 (the compiler + libraries) is licensed under GNU GPL 3.0
+- *exception:* the resulting files created by running the compiler are free to use in whatever way desired.
+
+
+What does Prog8 provide?
+------------------------
+
+- reduction of source code length over raw assembly
+- fast execution speed due to compilation to native assembly code. It's possible to write certain raster interrupt 'demoscene' effects purely in Prog8.
 - modularity, symbol scoping, subroutines
 - various data types other than just bytes (16-bit words, floats, strings)
-- automatic variable allocations, automatic string and array variables and string sharing
-- subroutines with a input- and output parameter signature
-- constant folding in expressions
+- floating point math is supported if the target system provides floating point library routines (C64 and Cx16 both do)
+- strings can contain escaped characters but also many symbols directly if they have a petscii equivalent, such as "♠♥♣♦π▚●○╳". Characters like ^, _, \, {, } and | are also accepted and converted to the closest petscii equivalents.
+- automatic static variable allocations, automatic string and array variables and string sharing
+- subroutines with input parameters and result values
+- high-level program optimizations
+- small program boilerplate/compilersupport overhead
+- programs can be run multiple times without reloading because of automatic variable (re)initializations.
 - conditional branches
-- 'when' statement to provide a concise jump table alternative to if/elseif chains
-- structs to group together sets of variables and manipulate them at once
-- floating point operations  (requires the C64 Basic ROM routines for this)
-- abstracting away low level aspects such as ZeroPage handling, program startup, explicit memory addresses
-- various code optimizations (code structure, logical and numerical expressions, unused code removal...)
+- ``when`` statement to provide a concise jump table alternative to if/elseif chains
+- ``in`` expression for concise and efficient multi-value/containment check 
+- many built-in functions such as ``sin``, ``cos``, ``rnd``, ``abs``, ``min``, ``max``, ``sqrt``, ``msb``, ``rol``, ``ror``, ``swap``, ``sort`` and ``reverse``
+- various powerful built-in libraries to do I/O, number conversions, graphics and more  
+- convenience abstractions for low level aspects such as ZeroPage handling, program startup, explicit memory addresses
 - inline assembly allows you to have full control when every cycle or byte matters
-- many built-in functions such as ``sin``, ``cos``, ``rnd``, ``abs``, ``min``, ``max``, ``sqrt``, ``msb``, ``rol``, ``ror``, ``swap``, ``memset``, ``memcopy``, ``sort`` and ``reverse``
+- supports the sixteen 'virtual' 16-bit registers R0 - R15 from the Commander X16, and provides them also on the C64.
+- encode strings and characters into petscii or screencodes as desired (C64/Cx16)
 
-Rapid edit-compile-run-debug cycle:
+*Rapid edit-compile-run-debug cycle:*
 
-- use a modern PC to do the work on
-- very quick compilation times
+- use a modern PC to do the work on, use nice editors and enjoy quick compilation times
 - can automatically run the program in the Vice emulator after succesful compilation
 - breakpoints, that let the Vice emulator drop into the monitor if execution hits them
 - source code labels automatically loaded in Vice emulator so it can show them in disassembly
 
-Prog8 is mainly targeted at the Commodore-64 machine at this time.
-Contributions to add support for other 8-bit (or other?!) machines are welcome.
+*Multiple supported compiler targets* (contributions to improve these or to add support for other machines are welcome!):
 
-Documentation/manual
---------------------
-https://prog8.readthedocs.io/
+- "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)
+- 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)
 
-Required tools
---------------
+
+
+Additional required tools
+-------------------------
 
 [64tass](https://sourceforge.net/projects/tass64/) - cross assembler. Install this on your shell path.
 A recent .exe version of this tool for Windows can be obtained from my [clone](https://github.com/irmen/64tass/releases) of this project.
 For other platforms it is very easy to compile it yourself (make ; make install).
 
-A **Java runtime (jre or jdk), version 8 or newer**  is required to run a prepackaged version of the compiler.
+A **Java runtime (jre or jdk), version 11 or newer**  is required to run a prepackaged version of the compiler.
 If you want to build it from source, you'll need a Java SDK + Kotlin 1.3.x SDK (or for instance,
 IntelliJ IDEA with the Kotlin plugin).
 
-It's handy to have a C-64 emulator or a real C-64 to run the programs on. The compiler assumes the presence
-of the [Vice emulator](http://vice-emu.sourceforge.net/)
+It's handy to have an emulator (or a real machine perhaps!) to run the programs on. The compiler assumes the presence
+of the [Vice emulator](http://vice-emu.sourceforge.net/)  for the C64 target,
+and the [x16emu emulator](https://github.com/commanderx16/x16-emulator) for the CommanderX16 target.
 
 
 Example code
@@ -64,44 +83,43 @@ Example code
 
 This code calculates prime numbers using the Sieve of Eratosthenes algorithm::
 
-    %import c64utils
+    %import textio
     %zeropage basicsafe
-
+    
     main {
-
+    
         ubyte[256] sieve
-        ubyte candidate_prime = 2
-
+        ubyte candidate_prime = 2       ; is increased in the loop
+    
         sub start() {
-            memset(sieve, 256, false)
-
-            c64scr.print("prime numbers up to 255:\n\n")
+            sys.memset(sieve, 256, false)   ; clear the sieve
+            txt.print("prime numbers up to 255:\n\n")
             ubyte amount=0
-            while true {
+            repeat {
                 ubyte prime = find_next_prime()
                 if prime==0
                     break
-                c64scr.print_ub(prime)
-                c64scr.print(", ")
+                txt.print_ub(prime)
+                txt.print(", ")
                 amount++
             }
-            c64.CHROUT('\n')
-            c64scr.print("number of primes (expected 54): ")
-            c64scr.print_ub(amount)
-            c64.CHROUT('\n')
+            txt.nl()
+            txt.print("number of primes (expected 54): ")
+            txt.print_ub(amount)
+            txt.nl()
         }
-
-
+    
         sub find_next_prime() -> ubyte {
-
             while sieve[candidate_prime] {
                 candidate_prime++
                 if candidate_prime==0
-                    return 0
+                    return 0        ; we wrapped; no more primes
             }
-
+    
+            ; found next one, mark the multiples and return it.
             sieve[candidate_prime] = true
             uword multiple = candidate_prime
+    
             while multiple < len(sieve) {
                 sieve[lsb(multiple)] = true
                 multiple += candidate_prime
@@ -111,11 +129,12 @@ 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)
 
-
 One of the included examples (wizzine.p8) animates a bunch of sprite balloons and looks like this:
 
 ![wizzine screen](docs/source/_static/wizzine.png)
@@ -127,3 +146,9 @@ Another example (cube3d-sprites.p8) draws the vertices of a rotating 3d cube:
 If you want to play a video game, a fully working Tetris clone is included in the examples:
 
 ![tehtriz_screen](docs/source/_static/tehtriz.png)
+
+There are a couple of examples specially made for the CommanderX16 compiler target.
+For instance here's a well known space ship animated in 3D with hidden line removal,
+in the CommanderX16 emulator:
+
+![cobra3d](docs/source/_static/cobra3d.png)

build.gradle

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

codeGenCpu6502/build.gradle

@@ -0,0 +1,46 @@
+
+plugins {
+    id 'java'
+    id 'application'
+    id "org.jetbrains.kotlin.jvm"
+}
+
+java {
+    toolchain {
+        languageVersion = JavaLanguageVersion.of(javaVersion)
+    }
+}
+
+compileKotlin {
+    kotlinOptions {
+        jvmTarget = javaVersion
+    }
+}
+
+compileTestKotlin {
+    kotlinOptions {
+        jvmTarget = javaVersion
+    }
+}
+
+dependencies {
+    implementation project(':compilerInterfaces')
+    implementation project(':compilerAst')
+    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8"
+    // implementation "org.jetbrains.kotlin:kotlin-reflect"
+    implementation "com.michael-bull.kotlin-result:kotlin-result-jvm:1.1.12"
+
+}
+
+sourceSets {
+    main {
+        java {
+            srcDirs = ["${project.projectDir}/src"]
+        }
+        resources {
+            srcDirs = ["${project.projectDir}/res"]
+        }
+    }
+}
+
+// note: there are no unit tests in this module!

codeGenCpu6502/codeGenCpu6502.iml

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

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

@@ -0,0 +1,452 @@
+package prog8.codegen.cpu6502
+
+import prog8.ast.Program
+import prog8.ast.base.VarDeclType
+import prog8.ast.expressions.NumericLiteral
+import prog8.ast.statements.VarDecl
+import prog8.compilerinterface.IMachineDefinition
+
+
+// note: see https://wiki.nesdev.org/w/index.php/6502_assembly_optimisations
+
+
+internal fun optimizeAssembly(lines: MutableList<String>, machine: IMachineDefinition, program: Program): Int {
+
+    var numberOfOptimizations = 0
+
+    var linesByFour = getLinesBy(lines, 4)
+
+    var mods = optimizeUselessStackByteWrites(linesByFour)
+    if(mods.isNotEmpty()) {
+        apply(mods, lines)
+        linesByFour = getLinesBy(lines, 4)
+        numberOfOptimizations++
+    }
+
+    mods = optimizeIncDec(linesByFour)
+    if(mods.isNotEmpty()) {
+        apply(mods, lines)
+        linesByFour = getLinesBy(lines, 4)
+        numberOfOptimizations++
+    }
+
+    mods = optimizeCmpSequence(linesByFour)
+    if(mods.isNotEmpty()) {
+        apply(mods, lines)
+        linesByFour = getLinesBy(lines, 4)
+        numberOfOptimizations++
+    }
+
+    mods = optimizeStoreLoadSame(linesByFour, machine, program)
+    if(mods.isNotEmpty()) {
+        apply(mods, lines)
+        linesByFour = getLinesBy(lines, 4)
+        numberOfOptimizations++
+    }
+
+    mods= optimizeJsrRts(linesByFour)
+    if(mods.isNotEmpty()) {
+        apply(mods, lines)
+        linesByFour = getLinesBy(lines, 4)
+        numberOfOptimizations++
+    }
+
+    var linesByFourteen = getLinesBy(lines, 14)
+    mods = optimizeSameAssignments(linesByFourteen, machine, program)
+    if(mods.isNotEmpty()) {
+        apply(mods, lines)
+        linesByFourteen = getLinesBy(lines, 14)
+        numberOfOptimizations++
+    }
+
+    // TODO more assembly optimizations
+
+    return numberOfOptimizations
+}
+
+private fun String.isBranch() = this.startsWith("b")
+private fun String.isStoreReg() = this.startsWith("sta") || this.startsWith("sty") || this.startsWith("stx")
+private fun String.isStoreRegOrZero() = this.isStoreReg() || this.startsWith("stz")
+private fun String.isLoadReg() = this.startsWith("lda") || this.startsWith("ldy") || this.startsWith("ldx")
+
+private class Modification(val lineIndex: Int, val remove: Boolean, val replacement: String?)
+
+private fun apply(modifications: List<Modification>, lines: MutableList<String>) {
+    for (modification in modifications.sortedBy { it.lineIndex }.reversed()) {
+        if(modification.remove)
+            lines.removeAt(modification.lineIndex)
+        else
+            lines[modification.lineIndex] = modification.replacement!!
+    }
+}
+
+private fun getLinesBy(lines: MutableList<String>, windowSize: Int) =
+// all lines (that aren't empty or comments) in sliding windows of certain size
+        lines.withIndex().filter { it.value.isNotBlank() && !it.value.trimStart().startsWith(';') }.windowed(windowSize, partialWindows = false)
+
+private fun optimizeCmpSequence(linesByFour: List<List<IndexedValue<String>>>): List<Modification> {
+    // when statement (on bytes) generates a sequence of:
+    //	 lda  $ce01,x
+    //	 cmp  #$20
+    //	 beq  check_prog8_s72choice_32
+    //	 lda  $ce01,x
+    //	 cmp  #$21
+    //	 beq  check_prog8_s73choice_33
+    // the repeated lda can be removed
+    val mods = mutableListOf<Modification>()
+    for(lines in linesByFour) {
+        if(lines[0].value.trim()=="lda  P8ESTACK_LO+1,x" &&
+                lines[1].value.trim().startsWith("cmp ") &&
+                lines[2].value.trim().startsWith("beq ") &&
+                lines[3].value.trim()=="lda  P8ESTACK_LO+1,x") {
+            mods.add(Modification(lines[3].index, true, null)) // remove the second lda
+        }
+    }
+    return mods
+}
+
+private fun optimizeUselessStackByteWrites(linesByFour: List<List<IndexedValue<String>>>): List<Modification> {
+    // sta on stack, dex, inx, lda from stack -> eliminate this useless stack byte write
+    // this is a lot harder for word values because the instruction sequence varies.
+    val mods = mutableListOf<Modification>()
+    for(lines in linesByFour) {
+        if(lines[0].value.trim()=="sta  P8ESTACK_LO,x" &&
+                lines[1].value.trim()=="dex" &&
+                lines[2].value.trim()=="inx" &&
+                lines[3].value.trim()=="lda  P8ESTACK_LO,x") {
+            mods.add(Modification(lines[1].index, true, null))
+            mods.add(Modification(lines[2].index, true, null))
+            mods.add(Modification(lines[3].index, true, null))
+        }
+    }
+    return mods
+}
+
+private fun optimizeSameAssignments(linesByFourteen: List<List<IndexedValue<String>>>, machine: IMachineDefinition, program: Program): List<Modification> {
+
+    // Optimize sequential assignments of the same value to various targets (bytes, words, floats)
+    // the float one is the one that requires 2*7=14 lines of code to check...
+    // The better place to do this is in the Compiler instead and never create these types of assembly, but hey
+
+    val mods = mutableListOf<Modification>()
+    for (lines in linesByFourteen) {
+        val first = lines[0].value.trimStart()
+        val second = lines[1].value.trimStart()
+        val third = lines[2].value.trimStart()
+        val fourth = lines[3].value.trimStart()
+        val fifth = lines[4].value.trimStart()
+        val sixth = lines[5].value.trimStart()
+        val seventh = lines[6].value.trimStart()
+        val eighth = lines[7].value.trimStart()
+
+        if(first.startsWith("lda") && second.startsWith("ldy") && third.startsWith("sta") && fourth.startsWith("sty") &&
+                fifth.startsWith("lda") && sixth.startsWith("ldy") && seventh.startsWith("sta") && eighth.startsWith("sty")) {
+            val firstvalue = first.substring(4)
+            val secondvalue = second.substring(4)
+            val thirdvalue = fifth.substring(4)
+            val fourthvalue = sixth.substring(4)
+            if(firstvalue==thirdvalue && secondvalue==fourthvalue) {
+                // lda/ldy   sta/sty   twice the same word -->  remove second lda/ldy pair (fifth and sixth lines)
+                val address1 = getAddressArg(first, program)
+                val address2 = getAddressArg(second, program)
+                if(address1==null || address2==null || (!machine.isIOAddress(address1) && !machine.isIOAddress(address2))) {
+                    mods.add(Modification(lines[4].index, true, null))
+                    mods.add(Modification(lines[5].index, true, null))
+                }
+            }
+        }
+
+        if(first.startsWith("lda") && second.startsWith("sta") && third.startsWith("lda") && fourth.startsWith("sta")) {
+            val firstvalue = first.substring(4)
+            val secondvalue = third.substring(4)
+            if(firstvalue==secondvalue) {
+                // lda value / sta ? / lda same-value / sta ?  -> remove second lda (third line)
+                val address = getAddressArg(first, program)
+                if(address==null || !machine.isIOAddress(address))
+                    mods.add(Modification(lines[2].index, true, null))
+            }
+        }
+
+        if(first.startsWith("lda") && second.startsWith("ldy") && third.startsWith("sta") && fourth.startsWith("sty") &&
+                fifth.startsWith("lda") && sixth.startsWith("ldy") &&
+                (seventh.startsWith("jsr  floats.copy_float") || seventh.startsWith("jsr  cx16flt.copy_float"))) {
+
+            val nineth = lines[8].value.trimStart()
+            val tenth = lines[9].value.trimStart()
+            val eleventh = lines[10].value.trimStart()
+            val twelveth = lines[11].value.trimStart()
+            val thirteenth = lines[12].value.trimStart()
+            val fourteenth = lines[13].value.trimStart()
+
+            if(eighth.startsWith("lda") && nineth.startsWith("ldy") && tenth.startsWith("sta") && eleventh.startsWith("sty") &&
+                    twelveth.startsWith("lda") && thirteenth.startsWith("ldy") &&
+                    (fourteenth.startsWith("jsr  floats.copy_float") || fourteenth.startsWith("jsr  cx16flt.copy_float"))) {
+
+                if(first.substring(4) == eighth.substring(4) && second.substring(4)==nineth.substring(4)) {
+                    // identical float init
+                    mods.add(Modification(lines[7].index, true, null))
+                    mods.add(Modification(lines[8].index, true, null))
+                    mods.add(Modification(lines[9].index, true, null))
+                    mods.add(Modification(lines[10].index, true, null))
+                }
+            }
+        }
+
+        var overlappingMods = false
+        /*
+        sta  prog8_lib.retval_intermX      ; remove
+        sty  prog8_lib.retval_intermY      ; remove
+        lda  prog8_lib.retval_intermX      ; remove
+        ldy  prog8_lib.retval_intermY      ; remove
+        sta  A1
+        sty  A2
+         */
+        if(first.isStoreReg() && second.isStoreReg()
+            && third.isLoadReg() && fourth.isLoadReg()
+            && fifth.isStoreReg() && sixth.isStoreReg()) {
+            val reg1 = first[2]
+            val reg2 = second[2]
+            val reg3 = third[2]
+            val reg4 = fourth[2]
+            val reg5 = fifth[2]
+            val reg6 = sixth[2]
+            if (reg1 == reg3 && reg1 == reg5 && reg2 == reg4 && reg2 == reg6) {
+                val firstvalue = first.substring(4)
+                val secondvalue = second.substring(4)
+                val thirdvalue = third.substring(4)
+                val fourthvalue = fourth.substring(4)
+                if(firstvalue.contains("prog8_lib.retval_interm") && secondvalue.contains("prog8_lib.retval_interm")
+                    && firstvalue==thirdvalue && secondvalue==fourthvalue) {
+                    mods.add(Modification(lines[0].index, true, null))
+                    mods.add(Modification(lines[1].index, true, null))
+                    mods.add(Modification(lines[2].index, true, null))
+                    mods.add(Modification(lines[3].index, true, null))
+                    overlappingMods = true
+                }
+            }
+        }
+
+        /*
+        sta  A1
+        sty  A2
+        lda  A1     ; can be removed
+        ldy  A2     ; can be removed if not followed by a branch instuction
+         */
+        if(!overlappingMods && first.isStoreReg() && second.isStoreReg()
+            && third.isLoadReg() && fourth.isLoadReg()) {
+            val reg1 = first[2]
+            val reg2 = second[2]
+            val reg3 = third[2]
+            val reg4 = fourth[2]
+            if(reg1==reg3 && reg2==reg4) {
+                val firstvalue = first.substring(4)
+                val secondvalue = second.substring(4)
+                val thirdvalue = third.substring(4)
+                val fourthvalue = fourth.substring(4)
+                if(firstvalue==thirdvalue && secondvalue == fourthvalue) {
+                    val address = getAddressArg(first, program)
+                    if(address==null || !machine.isIOAddress(address)) {
+                        overlappingMods = true
+                        mods.add(Modification(lines[2].index, true, null))
+                        if (!fifth.startsWith('b'))
+                            mods.add(Modification(lines[3].index, true, null))
+                    }
+                }
+            }
+        }
+
+        /*
+        sta  A1
+        sty  A2     ; ... or stz
+        lda  A1     ; can be removed if not followed by a branch instruction
+         */
+        if(!overlappingMods && first.isStoreReg() && second.isStoreRegOrZero()
+            && third.isLoadReg() && !fourth.isBranch()) {
+            val reg1 = first[2]
+            val reg3 = third[2]
+            if(reg1==reg3) {
+                val firstvalue = first.substring(4)
+                val thirdvalue = third.substring(4)
+                if(firstvalue==thirdvalue) {
+                    val address = getAddressArg(first, program)
+                    if(address==null || !machine.isIOAddress(address)) {
+                        overlappingMods = true
+                        mods.add(Modification(lines[2].index, true, null))
+                    }
+                }
+            }
+        }
+
+        /*
+        sta  A1
+        ldy  A1     ; make tay
+        sta  A1     ; remove
+         */
+        if(!overlappingMods && first.startsWith("sta") && second.isLoadReg()
+            && third.startsWith("sta") && second.length>4) {
+            val firstvalue = first.substring(4)
+            val secondvalue = second.substring(4)
+            val thirdvalue = third.substring(4)
+            if(firstvalue==secondvalue && firstvalue==thirdvalue) {
+                val address = getAddressArg(first, program)
+                if(address==null || !machine.isIOAddress(address)) {
+                    overlappingMods = true
+                    val reg2 = second[2]
+                    mods.add(Modification(lines[1].index, false, "  ta$reg2"))
+                    mods.add(Modification(lines[2].index, true, null))
+                }
+            }
+        }
+
+        /*
+        sta  A   ; or stz     double store, remove this first one
+        sta  A   ; or stz
+         */
+        if(!overlappingMods && first.isStoreRegOrZero() && second.isStoreRegOrZero()) {
+            if(first[2]==second[2]) {
+                val firstvalue = first.substring(4)
+                val secondvalue = second.substring(4)
+                if(firstvalue==secondvalue) {
+                    val address = getAddressArg(first, program)
+                    if(address==null || !machine.isIOAddress(address)) {
+                        overlappingMods = true
+                        mods.add(Modification(lines[0].index, true, null))
+                    }
+                }
+            }
+        }
+    }
+
+    return mods
+}
+
+private fun optimizeStoreLoadSame(linesByFour: List<List<IndexedValue<String>>>, machine: IMachineDefinition, program: Program): List<Modification> {
+    // sta X + lda X,  sty X + ldy X,   stx X + ldx X  -> the second instruction can OFTEN be eliminated
+    val mods = mutableListOf<Modification>()
+    for (lines in linesByFour) {
+        val first = lines[1].value.trimStart()
+        val second = lines[2].value.trimStart()
+
+        if ((first.startsWith("sta ") && second.startsWith("lda ")) ||
+                (first.startsWith("stx ") && second.startsWith("ldx ")) ||
+                (first.startsWith("sty ") && second.startsWith("ldy ")) ||
+                (first.startsWith("lda ") && second.startsWith("lda ")) ||
+                (first.startsWith("ldy ") && second.startsWith("ldy ")) ||
+                (first.startsWith("ldx ") && second.startsWith("ldx ")) ||
+                (first.startsWith("sta ") && second.startsWith("lda ")) ||
+                (first.startsWith("sty ") && second.startsWith("ldy ")) ||
+                (first.startsWith("stx ") && second.startsWith("ldx "))
+        ) {
+            val third = lines[3].value.trimStart()
+            val attemptRemove =
+                if(third.isBranch()) {
+                    // a branch instruction follows, we can only remove the load instruction if
+                    // another load instruction of the same register precedes the store instruction
+                    // (otherwise wrong cpu flags are used)
+                    val loadinstruction = second.substring(0, 3)
+                    lines[0].value.trimStart().startsWith(loadinstruction)
+                }
+                else {
+                    // no branch instruction follows, we can remove the load instruction
+                    val address = getAddressArg(lines[2].value, program)
+                    address==null || !machine.isIOAddress(address)
+                }
+
+            if(attemptRemove) {
+                val firstLoc = first.substring(4).trimStart()
+                val secondLoc = second.substring(4).trimStart()
+                if (firstLoc == secondLoc)
+                    mods.add(Modification(lines[2].index, true, null))
+            }
+        }
+        else if(first=="pha" && second=="pla" ||
+            first=="phx" && second=="plx" ||
+            first=="phy" && second=="ply" ||
+            first=="php" && second=="plp") {
+            mods.add(Modification(lines[1].index, true, null))
+            mods.add(Modification(lines[2].index, true, null))
+        } else if(first=="pha" && second=="plx") {
+            mods.add(Modification(lines[1].index, true, null))
+            mods.add(Modification(lines[2].index, false, "  tax"))
+        } else if(first=="pha" && second=="ply") {
+            mods.add(Modification(lines[1].index, true, null))
+            mods.add(Modification(lines[2].index, false, "  tay"))
+        } else if(first=="phx" && second=="pla") {
+            mods.add(Modification(lines[1].index, true, null))
+            mods.add(Modification(lines[2].index, false, "  txa"))
+        } else if(first=="phx" && second=="ply") {
+            mods.add(Modification(lines[1].index, true, null))
+            mods.add(Modification(lines[2].index, false, "  txy"))
+        } else if(first=="phy" && second=="pla") {
+            mods.add(Modification(lines[1].index, true, null))
+            mods.add(Modification(lines[2].index, false, "  tya"))
+        } else if(first=="phy" && second=="plx") {
+            mods.add(Modification(lines[1].index, true, null))
+            mods.add(Modification(lines[2].index, false, "  tyx"))
+        }
+    }
+    return mods
+}
+
+private val identifierRegex = Regex("""^([a-zA-Z_$][a-zA-Z\d_\.$]*)""")
+
+private fun getAddressArg(line: String, program: Program): UInt? {
+    val loadArg = line.trimStart().substring(3).trim()
+    return when {
+        loadArg.startsWith('$') -> loadArg.substring(1).toUIntOrNull(16)
+        loadArg.startsWith('%') -> loadArg.substring(1).toUIntOrNull(2)
+        loadArg.startsWith('#') -> null
+        loadArg.startsWith('(') -> null
+        loadArg[0].isLetter() -> {
+            val identMatch = identifierRegex.find(loadArg)
+            if(identMatch!=null) {
+                val identifier = identMatch.value
+                val decl = program.toplevelModule.lookup(identifier.split(".")) as? VarDecl
+                if(decl!=null) {
+                    when(decl.type){
+                        VarDeclType.VAR -> null
+                        VarDeclType.CONST,
+                        VarDeclType.MEMORY -> (decl.value as NumericLiteral).number.toUInt()
+                    }
+                }
+                else null
+            } else null
+        }
+        else -> loadArg.substring(1).toUIntOrNull()
+    }
+}
+
+private fun optimizeIncDec(linesByFour: List<List<IndexedValue<String>>>): List<Modification> {
+    // sometimes, iny+dey / inx+dex / dey+iny / dex+inx sequences are generated, these can be eliminated.
+    val mods = mutableListOf<Modification>()
+    for (lines in linesByFour) {
+        val first = lines[0].value
+        val second = lines[1].value
+        if ((" iny" in first || "\tiny" in first) && (" dey" in second || "\tdey" in second)
+                || (" inx" in first || "\tinx" in first) && (" dex" in second || "\tdex" in second)
+                || (" ina" in first || "\tina" in first) && (" dea" in second || "\tdea" in second)
+                || (" inc  a" in first || "\tinc  a" in first) && (" dec  a" in second || "\tdec  a" in second)
+                || (" dey" in first || "\tdey" in first) && (" iny" in second || "\tiny" in second)
+                || (" dex" in first || "\tdex" in first) && (" inx" in second || "\tinx" in second)
+                || (" dea" in first || "\tdea" in first) && (" ina" in second || "\tina" in second)
+                || (" dec  a" in first || "\tdec  a" in first) && (" inc  a" in second || "\tinc  a" in second)) {
+            mods.add(Modification(lines[0].index, true, null))
+            mods.add(Modification(lines[1].index, true, null))
+        }
+    }
+    return mods
+}
+
+private fun optimizeJsrRts(linesByFour: List<List<IndexedValue<String>>>): List<Modification> {
+    // jsr Sub + rts -> jmp Sub
+    val mods = mutableListOf<Modification>()
+    for (lines in linesByFour) {
+        val first = lines[0].value
+        val second = lines[1].value
+        if ((" jsr" in first || "\tjsr" in first ) && (" rts" in second || "\trts" in second)) {
+            mods += Modification(lines[0].index, false, lines[0].value.replace("jsr", "jmp"))
+            mods += Modification(lines[1].index, true, null)
+        }
+    }
+    return mods
+}

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

@@ -0,0 +1,147 @@
+package prog8.codegen.cpu6502
+
+import com.github.michaelbull.result.Ok
+import com.github.michaelbull.result.Result
+import com.github.michaelbull.result.mapError
+import prog8.compilerinterface.*
+import prog8.parser.SourceCode
+import java.io.File
+import java.nio.file.Path
+import kotlin.io.path.Path
+import kotlin.io.path.isRegularFile
+
+
+internal class AssemblyProgram(
+        override val name: String,
+        outputDir: Path,
+        private val compTarget: ICompilationTarget) : IAssemblyProgram {
+
+    private val assemblyFile = outputDir.resolve("$name.asm")
+    private val prgFile = outputDir.resolve("$name.prg")        // CBM prg executable program
+    private val xexFile = outputDir.resolve("$name.xex")        // Atari xex executable program
+    private val binFile = outputDir.resolve("$name.bin")
+    private val viceMonListFile = outputDir.resolve(viceMonListName(name))
+    private val listFile = outputDir.resolve("$name.list")
+
+    override fun assemble(options: CompilationOptions): Boolean {
+
+        val assemblerCommand: List<String>
+
+        when (compTarget.name) {
+            in setOf("c64", "c128", "cx16") -> {
+                // CBM machines .prg generation.
+
+                // add "-Wlong-branch"  to see warnings about conversion of branch instructions to jumps (default = do this silently)
+                val command = mutableListOf("64tass", "--ascii", "--case-sensitive", "--long-branch",
+                    "-Wall", "-Wno-strict-bool", "-Wno-shadow", // "-Werror",
+                    "--dump-labels", "--vice-labels", "--labels=$viceMonListFile", "--no-monitor"
+                )
+
+                if(options.asmQuiet)
+                    command.add("--quiet")
+
+                if(options.asmListfile)
+                    command.add("--list=$listFile")
+
+                val outFile = when (options.output) {
+                    OutputType.PRG -> {
+                        command.add("--cbm-prg")
+                        println("\nCreating prg for target ${compTarget.name}.")
+                        prgFile
+                    }
+                    OutputType.RAW -> {
+                        command.add("--nostart")
+                        println("\nCreating raw binary for target ${compTarget.name}.")
+                        binFile
+                    }
+                    else -> throw AssemblyError("invalid output type")
+                }
+                command.addAll(listOf("--output", outFile.toString(), assemblyFile.toString()))
+                assemblerCommand = command
+
+            }
+            "atari" -> {
+                // Atari800XL .xex generation.
+
+                // TODO are these options okay?
+                val command = mutableListOf("64tass", "--ascii", "--case-sensitive", "--long-branch",
+                    "-Wall", "-Wno-strict-bool", "-Wno-shadow", // "-Werror",
+                    "--no-monitor"
+                )
+
+                if(options.asmQuiet)
+                    command.add("--quiet")
+
+                if(options.asmListfile)
+                    command.add("--list=$listFile")
+
+                val outFile = when (options.output) {
+                    OutputType.XEX -> {
+                        command.add("--atari-xex")
+                        println("\nCreating xex for target ${compTarget.name}.")
+                        xexFile
+                    }
+                    OutputType.RAW -> {
+                        command.add("--nostart")
+                        println("\nCreating raw binary for target ${compTarget.name}.")
+                        binFile
+                    }
+                    else -> throw AssemblyError("invalid output type")
+                }
+                command.addAll(listOf("--output", outFile.toString(), assemblyFile.toString()))
+                assemblerCommand = command
+            }
+            else -> throw AssemblyError("invalid compilation target")
+        }
+
+        val proc = ProcessBuilder(assemblerCommand).inheritIO().start()
+        val result = proc.waitFor()
+        if (result == 0 && compTarget.name!="atari") {
+            removeGeneratedLabelsFromMonlist()
+            generateBreakpointList()
+        }
+        return result==0
+    }
+
+    private fun removeGeneratedLabelsFromMonlist() {
+        val pattern = Regex("""al (\w+) \S+${generatedLabelPrefix}.+?""")
+        val lines = viceMonListFile.toFile().readLines()
+        viceMonListFile.toFile().outputStream().bufferedWriter().use {
+            for (line in lines) {
+                if(pattern.matchEntire(line)==null)
+                    it.write(line+"\n")
+            }
+        }
+    }
+
+    private fun generateBreakpointList() {
+        // builds list of breakpoints, appends to monitor list file
+        val breakpoints = mutableListOf<String>()
+        val pattern = Regex("""al (\w+) \S+_prog8_breakpoint_\d+.?""")      // gather breakpoints by the source label that's generated for them
+        for (line in viceMonListFile.toFile().readLines()) {
+            val match = pattern.matchEntire(line)
+            if (match != null)
+                breakpoints.add("break \$" + match.groupValues[1])
+        }
+        val num = breakpoints.size
+        breakpoints.add(0, "; vice monitor breakpoint list now follows")
+        breakpoints.add(1, "; $num breakpoints have been defined")
+        breakpoints.add(2, "del")
+        viceMonListFile.toFile().appendText(breakpoints.joinToString("\n") + "\n")
+    }
+}
+
+
+internal fun loadAsmIncludeFile(filename: String, source: SourceCode): Result<String, NoSuchFileException> {
+    return if (filename.startsWith(SourceCode.libraryFilePrefix)) {
+        return com.github.michaelbull.result.runCatching {
+            SourceCode.Resource("/prog8lib/${filename.substring(SourceCode.libraryFilePrefix.length)}").text
+        }.mapError { NoSuchFileException(File(filename)) }
+    } else {
+        val sib = Path(source.origin).resolveSibling(filename)
+        if (sib.isRegularFile())
+            Ok(SourceCode.File(sib).text)
+        else
+            Ok(SourceCode.File(Path(filename)).text)
+    }
+}

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

@@ -0,0 +1,859 @@
+package prog8.codegen.cpu6502
+
+import prog8.ast.Program
+import prog8.ast.base.*
+import prog8.ast.expressions.*
+import prog8.ast.toHex
+import prog8.compilerinterface.AssemblyError
+import prog8.compilerinterface.CpuType
+import kotlin.math.absoluteValue
+
+internal class ExpressionsAsmGen(private val program: Program,
+                                 private val asmgen: AsmGen,
+                                 private val allocator: VariableAllocator) {
+
+    @Deprecated("avoid calling this as it generates slow evalstack based code")
+    internal fun translateExpression(expression:Expression) {
+        if (this.asmgen.options.slowCodegenWarnings) {
+            asmgen.errors.warn("slow stack evaluation used for expression $expression", expression.position)
+        }
+        translateExpressionInternal(expression)
+    }
+
+
+    // the rest of the methods are all PRIVATE
+
+
+    private fun translateExpressionInternal(expression: Expression) {
+
+        when(expression) {
+            is PrefixExpression -> translateExpression(expression)
+            is BinaryExpression -> translateExpression(expression)
+            is ArrayIndexedExpression -> translateExpression(expression)
+            is TypecastExpression -> translateExpression(expression)
+            is AddressOf -> translateExpression(expression)
+            is DirectMemoryRead -> asmgen.translateDirectMemReadExpressionToRegAorStack(expression, true)
+            is NumericLiteral -> translateExpression(expression)
+            is IdentifierReference -> translateExpression(expression)
+            is FunctionCallExpression -> translateFunctionCallResultOntoStack(expression)
+            is BuiltinFunctionCall -> asmgen.translateBuiltinFunctionCallExpression(expression, true, null)
+            is PipeExpression -> asmgen.translatePipeExpression(expression.source, expression.segments,
+                                                                expression, isStatement = false, pushResultOnEstack = true )
+            is ContainmentCheck -> throw AssemblyError("containment check as complex expression value is not supported")
+            is ArrayLiteral, is StringLiteral -> throw AssemblyError("no asm gen for string/array literal value assignment - should have been replaced by a variable")
+            is RangeExpression -> throw AssemblyError("range expression should have been changed into array values")
+            is CharLiteral -> throw AssemblyError("charliteral should have been replaced by ubyte using certain encoding")
+            else -> TODO("missing expression asmgen for $expression")
+        }
+    }
+
+    private fun translateFunctionCallResultOntoStack(call: FunctionCallExpression) {
+        // only for use in nested expression evaluation
+
+        val sub = call.target.targetSubroutine(program)!!
+        asmgen.saveXbeforeCall(call)
+        asmgen.translateFunctionCall(call, true)
+        if(sub.regXasResult()) {
+            // store the return value in X somewhere that we can access again below
+            asmgen.out("  stx  P8ZP_SCRATCH_REG")
+        }
+        asmgen.restoreXafterCall(call)
+
+        val returns = sub.returntypes.zip(sub.asmReturnvaluesRegisters)
+        for ((_, reg) in returns) {
+            // result value is in cpu or status registers, put it on the stack instead (as we're evaluating an expression tree)
+            if (reg.registerOrPair != null) {
+                when (reg.registerOrPair!!) {
+                    RegisterOrPair.A -> asmgen.out("  sta  P8ESTACK_LO,x |  dex")
+                    RegisterOrPair.Y -> asmgen.out("  tya |  sta  P8ESTACK_LO,x |  dex")
+                    RegisterOrPair.AY -> asmgen.out("  sta  P8ESTACK_LO,x |  tya |  sta  P8ESTACK_HI,x |  dex")
+                    RegisterOrPair.X -> asmgen.out("  lda  P8ZP_SCRATCH_REG |  sta  P8ESTACK_LO,x |  dex")
+                    RegisterOrPair.AX -> asmgen.out("  sta  P8ESTACK_LO,x |  lda  P8ZP_SCRATCH_REG |  sta  P8ESTACK_HI,x |  dex")
+                    RegisterOrPair.XY -> asmgen.out("  tya |  sta  P8ESTACK_HI,x |  lda  P8ZP_SCRATCH_REG |  sta  P8ESTACK_LO,x |  dex")
+                    RegisterOrPair.FAC1 -> asmgen.out("  jsr  floats.push_fac1")
+                    RegisterOrPair.FAC2 -> asmgen.out("  jsr  floats.push_fac2")
+                    RegisterOrPair.R0,
+                    RegisterOrPair.R1,
+                    RegisterOrPair.R2,
+                    RegisterOrPair.R3,
+                    RegisterOrPair.R4,
+                    RegisterOrPair.R5,
+                    RegisterOrPair.R6,
+                    RegisterOrPair.R7,
+                    RegisterOrPair.R8,
+                    RegisterOrPair.R9,
+                    RegisterOrPair.R10,
+                    RegisterOrPair.R11,
+                    RegisterOrPair.R12,
+                    RegisterOrPair.R13,
+                    RegisterOrPair.R14,
+                    RegisterOrPair.R15 -> {
+                        asmgen.out(
+                            """
+                            lda  cx16.${reg.registerOrPair.toString().lowercase()}
+                            sta  P8ESTACK_LO,x
+                            lda  cx16.${reg.registerOrPair.toString().lowercase()}+1
+                            sta  P8ESTACK_HI,x
+                            dex
+                        """)
+                    }
+                }
+            } else when(reg.statusflag) {
+                Statusflag.Pc -> {
+                    asmgen.out("""
+                        lda  #0
+                        rol  a
+                        sta  P8ESTACK_LO,x
+                        dex""")
+                }
+                Statusflag.Pz -> {
+                    asmgen.out("""
+                        beq  +
+                        lda  #0
+                        beq  ++
++                           lda  #1
++                           sta  P8ESTACK_LO,x
+                        dex""")
+                }
+                Statusflag.Pv -> {
+                    asmgen.out("""
+                        bvs  +
+                        lda  #0
+                        beq  ++
++                           lda  #1
++                           sta  P8ESTACK_LO,x
+                        dex""")
+                }
+                Statusflag.Pn -> {
+                    asmgen.out("""
+                        bmi  +
+                        lda  #0
+                        beq  ++
++                           lda  #1
++                           sta  P8ESTACK_LO,x
+                        dex""")
+                }
+                null -> {}
+            }
+        }
+    }
+
+    private fun translateExpression(typecast: TypecastExpression) {
+        translateExpressionInternal(typecast.expression)
+        when(typecast.expression.inferType(program).getOr(DataType.UNDEFINED)) {
+            DataType.UBYTE -> {
+                when(typecast.type) {
+                    DataType.UBYTE, DataType.BYTE -> {}
+                    DataType.UWORD, DataType.WORD -> {
+                        if(asmgen.isTargetCpu(CpuType.CPU65c02))
+                            asmgen.out("  stz  P8ESTACK_HI+1,x")
+                        else
+                            asmgen.out("  lda  #0  |  sta  P8ESTACK_HI+1,x")
+                    }
+                    DataType.FLOAT -> asmgen.out(" jsr  floats.stack_ub2float")
+                    in PassByReferenceDatatypes -> throw AssemblyError("cannot cast to a pass-by-reference datatype")
+                    else -> throw AssemblyError("weird type")
+                }
+            }
+            DataType.BYTE -> {
+                when(typecast.type) {
+                    DataType.UBYTE, DataType.BYTE -> {}
+                    DataType.UWORD, DataType.WORD -> asmgen.signExtendStackLsb(DataType.BYTE)
+                    DataType.FLOAT -> asmgen.out(" jsr  floats.stack_b2float")
+                    in PassByReferenceDatatypes -> throw AssemblyError("cannot cast to a pass-by-reference datatype")
+                    else -> throw AssemblyError("weird type")
+                }
+            }
+            DataType.UWORD -> {
+                when(typecast.type) {
+                    DataType.BYTE, DataType.UBYTE -> {}
+                    DataType.WORD, DataType.UWORD -> {}
+                    DataType.FLOAT -> asmgen.out(" jsr  floats.stack_uw2float")
+                    in PassByReferenceDatatypes -> throw AssemblyError("cannot cast to a pass-by-reference datatype")
+                    else -> throw AssemblyError("weird type")
+                }
+            }
+            DataType.WORD -> {
+                when(typecast.type) {
+                    DataType.BYTE, DataType.UBYTE -> {}
+                    DataType.WORD, DataType.UWORD -> {}
+                    DataType.FLOAT -> asmgen.out(" jsr  floats.stack_w2float")
+                    in PassByReferenceDatatypes -> throw AssemblyError("cannot cast to a pass-by-reference datatype")
+                    else -> throw AssemblyError("weird type")
+                }
+            }
+            DataType.FLOAT -> {
+                when(typecast.type) {
+                    DataType.UBYTE -> asmgen.out(" jsr  floats.stack_float2uw")
+                    DataType.BYTE -> asmgen.out(" jsr  floats.stack_float2w")
+                    DataType.UWORD -> asmgen.out(" jsr  floats.stack_float2uw")
+                    DataType.WORD -> asmgen.out(" jsr  floats.stack_float2w")
+                    DataType.FLOAT -> {}
+                    in PassByReferenceDatatypes -> throw AssemblyError("cannot cast to a pass-by-reference datatype")
+                    else -> throw AssemblyError("weird type")
+                }
+            }
+            DataType.STR -> {
+                if (typecast.type != DataType.UWORD && typecast.type == DataType.STR)
+                    throw AssemblyError("cannot typecast a string into another incompatitble type")
+            }
+            in PassByReferenceDatatypes -> throw AssemblyError("cannot cast pass-by-reference value into another type")
+            else -> throw AssemblyError("weird type")
+        }
+    }
+
+    private fun translateExpression(expr: AddressOf) {
+        val name = asmgen.asmVariableName(expr.identifier)
+        asmgen.out("  lda  #<$name |  sta  P8ESTACK_LO,x |  lda  #>$name  |  sta  P8ESTACK_HI,x  | dex")
+    }
+
+    private fun translateExpression(expr: NumericLiteral) {
+        when(expr.type) {
+            DataType.UBYTE, DataType.BYTE -> asmgen.out(" lda  #${expr.number.toHex()}  | sta  P8ESTACK_LO,x  | dex")
+            DataType.UWORD, DataType.WORD -> asmgen.out("""
+                lda  #<${expr.number.toHex()}
+                sta  P8ESTACK_LO,x
+                lda  #>${expr.number.toHex()}
+                sta  P8ESTACK_HI,x
+                dex
+            """)
+            DataType.FLOAT -> {
+                val floatConst = allocator.getFloatAsmConst(expr.number)
+                asmgen.out(" lda  #<$floatConst |  ldy  #>$floatConst |  jsr  floats.push_float")
+            }
+            else -> throw AssemblyError("weird type")
+        }
+    }
+
+    private fun translateExpression(expr: IdentifierReference) {
+        val varname = asmgen.asmVariableName(expr)
+        when(expr.inferType(program).getOr(DataType.UNDEFINED)) {
+            DataType.UBYTE, DataType.BYTE -> {
+                asmgen.out("  lda  $varname  |  sta  P8ESTACK_LO,x  |  dex")
+            }
+            DataType.UWORD, DataType.WORD -> {
+                asmgen.out("  lda  $varname  |  sta  P8ESTACK_LO,x  |  lda  $varname+1 |  sta  P8ESTACK_HI,x |  dex")
+            }
+            DataType.FLOAT -> {
+                asmgen.out(" lda  #<$varname |  ldy  #>$varname|  jsr  floats.push_float")
+            }
+            in IterableDatatypes -> {
+                asmgen.out("  lda  #<$varname  |  sta  P8ESTACK_LO,x  |  lda  #>$varname |  sta  P8ESTACK_HI,x |  dex")
+            }
+            else -> throw AssemblyError("stack push weird variable type $expr")
+        }
+    }
+
+    private fun translateExpression(expr: BinaryExpression) {
+        // Uses evalstack to evaluate the given expression.
+        // TODO we're slowly reducing the number of places where this is called and instead replace that by more efficient assignment-form code (using temp var or register for instance).
+        val leftIDt = expr.left.inferType(program)
+        val rightIDt = expr.right.inferType(program)
+        if(!leftIDt.isKnown || !rightIDt.isKnown)
+            throw AssemblyError("can't infer type of both expression operands")
+
+        val leftDt = leftIDt.getOrElse { throw AssemblyError("unknown dt") }
+        val rightDt = rightIDt.getOrElse { throw AssemblyError("unknown dt") }
+        // see if we can apply some optimized routines
+        when(expr.operator) {
+            "+" -> {
+                if(leftDt in IntegerDatatypes && rightDt in IntegerDatatypes) {
+                    val leftVal = expr.left.constValue(program)?.number?.toInt()
+                    val rightVal = expr.right.constValue(program)?.number?.toInt()
+                    if (leftVal!=null && leftVal in -4..4) {
+                        translateExpressionInternal(expr.right)
+                        if(rightDt in ByteDatatypes) {
+                            val incdec = if(leftVal<0) "dec" else "inc"
+                            repeat(leftVal.absoluteValue) {
+                                asmgen.out("  $incdec  P8ESTACK_LO+1,x")
+                            }
+                        } else {
+                            // word
+                            if(leftVal<0) {
+                                repeat(leftVal.absoluteValue) {
+                                    asmgen.out("""
+                                        lda  P8ESTACK_LO+1,x
+                                        bne  +
+                                        dec  P8ESTACK_HI+1,x
++                                       dec  P8ESTACK_LO+1,x""")
+                                }
+                            } else {
+                                repeat(leftVal) {
+                                    asmgen.out("""
+                                        inc  P8ESTACK_LO+1,x
+                                        bne  +
+                                        inc  P8ESTACK_HI+1,x
++""")
+                                }
+                            }
+                        }
+                        return
+                    }
+                    else if (rightVal!=null && rightVal in -4..4)
+                    {
+                        translateExpressionInternal(expr.left)
+                        if(leftDt in ByteDatatypes) {
+                            val incdec = if(rightVal<0) "dec" else "inc"
+                            repeat(rightVal.absoluteValue) {
+                                asmgen.out("  $incdec  P8ESTACK_LO+1,x")
+                            }
+                        } else {
+                            // word
+                            if(rightVal<0) {
+                                repeat(rightVal.absoluteValue) {
+                                    asmgen.out("""
+                                        lda  P8ESTACK_LO+1,x
+                                        bne  +
+                                        dec  P8ESTACK_HI+1,x
++                                       dec  P8ESTACK_LO+1,x""")
+                                }
+                            } else {
+                                repeat(rightVal) {
+                                    asmgen.out("""
+                                        inc  P8ESTACK_LO+1,x
+                                        bne  +
+                                        inc  P8ESTACK_HI+1,x
++""")
+                                }
+                            }
+                        }
+                        return
+                    }
+                }
+            }
+            "-" -> {
+                if(leftDt in IntegerDatatypes && rightDt in IntegerDatatypes) {
+                    val rightVal = expr.right.constValue(program)?.number?.toInt()
+                    if (rightVal!=null && rightVal in -4..4)
+                    {
+                        translateExpressionInternal(expr.left)
+                        if(leftDt in ByteDatatypes) {
+                            val incdec = if(rightVal<0) "inc" else "dec"
+                            repeat(rightVal.absoluteValue) {
+                                asmgen.out("  $incdec  P8ESTACK_LO+1,x")
+                            }
+                        } else {
+                            // word
+                            if(rightVal>0) {
+                                repeat(rightVal.absoluteValue) {
+                                    asmgen.out("""
+                                        lda  P8ESTACK_LO+1,x
+                                        bne  +
+                                        dec  P8ESTACK_HI+1,x
++                                       dec  P8ESTACK_LO+1,x""")
+                                }
+                            } else {
+                                repeat(rightVal) {
+                                    asmgen.out("""
+                                        inc  P8ESTACK_LO+1,x
+                                        bne  +
+                                        inc  P8ESTACK_HI+1,x
++""")
+                                }
+                            }
+                        }
+                        return
+                    }
+                }
+            }
+            ">>" -> {
+                val amount = expr.right.constValue(program)?.number?.toInt()
+                if(amount!=null) {
+                    translateExpressionInternal(expr.left)
+                    when (leftDt) {
+                        DataType.UBYTE -> {
+                            if (amount <= 2)
+                                repeat(amount) { asmgen.out(" lsr  P8ESTACK_LO+1,x") }
+                            else {
+                                asmgen.out(" lda  P8ESTACK_LO+1,x")
+                                repeat(amount) { asmgen.out(" lsr  a") }
+                                asmgen.out(" sta  P8ESTACK_LO+1,x")
+                            }
+                        }
+                        DataType.BYTE -> {
+                            if (amount <= 2)
+                                repeat(amount) { asmgen.out(" lda  P8ESTACK_LO+1,x |  asl  a |  ror  P8ESTACK_LO+1,x") }
+                            else {
+                                asmgen.out(" lda  P8ESTACK_LO+1,x |  sta  P8ZP_SCRATCH_B1")
+                                repeat(amount) { asmgen.out(" asl  a |  ror  P8ZP_SCRATCH_B1 |  lda  P8ZP_SCRATCH_B1") }
+                                asmgen.out(" sta  P8ESTACK_LO+1,x")
+                            }
+                        }
+                        DataType.UWORD -> {
+                            if(amount>=16) {
+                                if(asmgen.isTargetCpu(CpuType.CPU65c02))
+                                    asmgen.out("  stz  P8ESTACK_LO+1,x |  stz  P8ESTACK_HI+1,x")
+                                else
+                                    asmgen.out("  lda  #0 |  sta  P8ESTACK_LO+1,x |  sta  P8ESTACK_HI+1,x")
+                                return
+                            }
+                            var left = amount
+                            while (left >= 7) {
+                                asmgen.out(" jsr  math.shift_right_uw_7")
+                                left -= 7
+                            }
+                            if (left in 0..2)
+                                repeat(left) { asmgen.out(" lsr  P8ESTACK_HI+1,x |  ror  P8ESTACK_LO+1,x") }
+                            else
+                                asmgen.out(" jsr  math.shift_right_uw_$left")
+                        }
+                        DataType.WORD -> {
+                            if(amount>=16) {
+                                asmgen.out("""
+                                    lda  P8ESTACK_HI+1,x
+                                    bmi  +
+                                    lda  #0
+                                    sta  P8ESTACK_LO+1,x
+                                    sta  P8ESTACK_HI+1,x
+                                    beq  ++
++                                   lda  #255
+                                    sta  P8ESTACK_LO+1,x
+                                    sta  P8ESTACK_HI+1,x
++""")
+                                return
+                            }
+                            var left = amount
+                            while (left >= 7) {
+                                asmgen.out(" jsr  math.shift_right_w_7")
+                                left -= 7
+                            }
+                            if (left in 0..2)
+                                repeat(left) { asmgen.out(" lda  P8ESTACK_HI+1,x |  asl  a  |  ror  P8ESTACK_HI+1,x |  ror  P8ESTACK_LO+1,x") }
+                            else
+                                asmgen.out(" jsr  math.shift_right_w_$left")
+                        }
+                        else -> throw AssemblyError("weird type")
+                    }
+                    return
+                }
+            }
+            "<<" -> {
+                val amount = expr.right.constValue(program)?.number?.toInt()
+                if(amount!=null) {
+                    translateExpressionInternal(expr.left)
+                    if (leftDt in ByteDatatypes) {
+                        if (amount <= 2)
+                            repeat(amount) { asmgen.out("  asl  P8ESTACK_LO+1,x") }
+                        else {
+                            asmgen.out("  lda  P8ESTACK_LO+1,x")
+                            repeat(amount) { asmgen.out("  asl  a") }
+                            asmgen.out("  sta  P8ESTACK_LO+1,x")
+                        }
+                    } else {
+                        var left = amount
+                        while (left >= 7) {
+                            asmgen.out(" jsr  math.shift_left_w_7")
+                            left -= 7
+                        }
+                        if (left in 0..2)
+                            repeat(left) { asmgen.out("  asl  P8ESTACK_LO+1,x |  rol  P8ESTACK_HI+1,x") }
+                        else
+                            asmgen.out(" jsr  math.shift_left_w_$left")
+                    }
+                    return
+                }
+            }
+            "*" -> {
+                if(leftDt in IntegerDatatypes && rightDt in IntegerDatatypes) {
+                    val leftVar = expr.left as? IdentifierReference
+                    val rightVar = expr.right as? IdentifierReference
+                    if(leftVar!=null && rightVar!=null && leftVar==rightVar)
+                        return translateSquared(leftVar, leftDt)
+                }
+
+                val value = expr.right.constValue(program)
+                if(value!=null) {
+                    if(rightDt in IntegerDatatypes) {
+                        val amount = value.number.toInt()
+                        if(amount==2) {
+                            // optimize x*2 common case
+                            translateExpressionInternal(expr.left)
+                            if(leftDt in ByteDatatypes) {
+                                asmgen.out("  asl  P8ESTACK_LO+1,x")
+                            } else {
+                                asmgen.out("  asl  P8ESTACK_LO+1,x |  rol  P8ESTACK_HI+1,x")
+                            }
+                            return
+                        }
+                        when(rightDt) {
+                            DataType.UBYTE -> {
+                                if(amount in asmgen.optimizedByteMultiplications) {
+                                    translateExpressionInternal(expr.left)
+                                    asmgen.out(" jsr  math.stack_mul_byte_$amount")
+                                    return
+                                }
+                            }
+                            DataType.BYTE -> {
+                                if(amount in asmgen.optimizedByteMultiplications) {
+                                    translateExpressionInternal(expr.left)
+                                    asmgen.out(" jsr  math.stack_mul_byte_$amount")
+                                    return
+                                }
+                                if(amount.absoluteValue in asmgen.optimizedByteMultiplications) {
+                                    translateExpressionInternal(expr.left)
+                                    asmgen.out(" jsr  prog8_lib.neg_b |  jsr  math.stack_mul_byte_${amount.absoluteValue}")
+                                    return
+                                }
+                            }
+                            DataType.UWORD -> {
+                                if(amount in asmgen.optimizedWordMultiplications) {
+                                    translateExpressionInternal(expr.left)
+                                    asmgen.out(" jsr  math.stack_mul_word_$amount")
+                                    return
+                                }
+                            }
+                            DataType.WORD -> {
+                                if(amount in asmgen.optimizedWordMultiplications) {
+                                    translateExpressionInternal(expr.left)
+                                    asmgen.out(" jsr  math.stack_mul_word_$amount")
+                                    return
+                                }
+                                if(amount.absoluteValue in asmgen.optimizedWordMultiplications) {
+                                    translateExpressionInternal(expr.left)
+                                    asmgen.out(" jsr  prog8_lib.neg_w |  jsr  math.stack_mul_word_${amount.absoluteValue}")
+                                    return
+                                }
+                            }
+                            else -> {}
+                        }
+                    }
+                }
+            }
+            "/" -> {
+                if(leftDt in IntegerDatatypes && rightDt in IntegerDatatypes) {
+                    val rightVal = expr.right.constValue(program)?.number?.toInt()
+                    if(rightVal!=null && rightVal==2) {
+                        translateExpressionInternal(expr.left)
+                        when(leftDt) {
+                            DataType.UBYTE -> asmgen.out("  lsr  P8ESTACK_LO+1,x")
+                            DataType.BYTE -> asmgen.out("  lda  P8ESTACK_LO+1,x |  asl  a |  ror  P8ESTACK_LO+1,x")
+                            DataType.UWORD -> asmgen.out("  lsr  P8ESTACK_HI+1,x |  ror  P8ESTACK_LO+1,x")
+                            DataType.WORD -> asmgen.out("  lda  P8ESTACK_HI+1,x |  asl  a |  ror  P8ESTACK_HI+1,x |  ror  P8ESTACK_LO+1,x")
+                            else -> throw AssemblyError("wrong dt")
+                        }
+                        return
+                    }
+                }
+            }
+            in ComparisonOperators -> {
+                if(leftDt in NumericDatatypes && rightDt in NumericDatatypes) {
+                    val rightVal = expr.right.constValue(program)?.number?.toInt()
+                    if(rightVal==0)
+                        return translateComparisonWithZero(expr.left, leftDt, expr.operator)
+                }
+            }
+        }
+
+        if((leftDt in ByteDatatypes && rightDt !in ByteDatatypes)
+                || (leftDt in WordDatatypes && rightDt !in WordDatatypes))
+            throw AssemblyError("binary operator ${expr.operator} left/right dt not identical")
+
+        if(leftDt==DataType.STR && rightDt==DataType.STR && expr.operator in ComparisonOperators) {
+            translateCompareStrings(expr.left, expr.operator, expr.right)
+        }
+        else {
+            // the general, non-optimized cases  TODO optimize more cases.... (or one day just don't use the evalstack at all anymore)
+            translateExpressionInternal(expr.left)
+            translateExpressionInternal(expr.right)
+            when (leftDt) {
+                in ByteDatatypes -> translateBinaryOperatorBytes(expr.operator, leftDt)
+                in WordDatatypes -> translateBinaryOperatorWords(expr.operator, leftDt)
+                DataType.FLOAT -> translateBinaryOperatorFloats(expr.operator)
+                else -> throw AssemblyError("non-numerical datatype")
+            }
+        }
+    }
+
+    private fun translateComparisonWithZero(expr: Expression, dt: DataType, operator: String) {
+        translateExpressionInternal(expr)
+        when(operator) {
+            "==" -> {
+                when(dt) {
+                    DataType.UBYTE, DataType.BYTE -> asmgen.out("  jsr  prog8_lib.equalzero_b")
+                    DataType.UWORD, DataType.WORD -> asmgen.out("  jsr  prog8_lib.equalzero_w")
+                    DataType.FLOAT -> asmgen.out("  jsr  floats.equal_zero")
+                    else -> throw AssemblyError("wrong dt")
+                }
+            }
+            "!=" -> {
+                when(dt) {
+                    DataType.UBYTE, DataType.BYTE -> asmgen.out("  jsr  prog8_lib.notequalzero_b")
+                    DataType.UWORD, DataType.WORD -> asmgen.out("  jsr  prog8_lib.notequalzero_w")
+                    DataType.FLOAT -> asmgen.out("  jsr  floats.notequal_zero")
+                    else -> throw AssemblyError("wrong dt")
+                }
+            }
+            "<" -> {
+                if(dt==DataType.UBYTE || dt==DataType.UWORD)
+                    return translateExpressionInternal(NumericLiteral.fromBoolean(false, expr.position))
+                when(dt) {
+                    DataType.BYTE -> asmgen.out("  jsr  prog8_lib.lesszero_b")
+                    DataType.WORD -> asmgen.out("  jsr  prog8_lib.lesszero_w")
+                    DataType.FLOAT -> asmgen.out("  jsr  floats.less_zero")
+                    else -> throw AssemblyError("wrong dt")
+                }
+            }
+            ">" -> {
+                when(dt) {
+                    DataType.UBYTE -> asmgen.out("  jsr  prog8_lib.greaterzero_ub")
+                    DataType.BYTE -> asmgen.out("  jsr  prog8_lib.greaterzero_sb")
+                    DataType.UWORD -> asmgen.out("  jsr  prog8_lib.greaterzero_uw")
+                    DataType.WORD -> asmgen.out("  jsr  prog8_lib.greaterzero_sw")
+                    DataType.FLOAT -> asmgen.out("  jsr  floats.greater_zero")
+                    else -> throw AssemblyError("wrong dt")
+                }
+            }
+            "<=" -> {
+                when(dt) {
+                    DataType.UBYTE -> asmgen.out("  jsr  prog8_lib.equalzero_b")
+                    DataType.BYTE -> asmgen.out("  jsr  prog8_lib.lessequalzeros_b")
+                    DataType.UWORD -> asmgen.out("  jsr  prog8_lib.equalzero_w")
+                    DataType.WORD -> asmgen.out("  jsr  prog8_lib.lessequalzero_sw")
+                    DataType.FLOAT -> asmgen.out("  jsr  floats.lessequal_zero")
+                    else -> throw AssemblyError("wrong dt")
+                }
+            }
+            ">=" -> {
+                if(dt==DataType.UBYTE || dt==DataType.UWORD)
+                    return translateExpressionInternal(NumericLiteral.fromBoolean(true, expr.position))
+                when(dt) {
+                    DataType.BYTE -> asmgen.out("  jsr  prog8_lib.greaterequalzero_sb")
+                    DataType.WORD -> asmgen.out("  jsr  prog8_lib.greaterequalzero_sw")
+                    DataType.FLOAT -> asmgen.out("  jsr  floats.greaterequal_zero")
+                    else -> throw AssemblyError("wrong dt")
+                }
+            }
+            else -> throw AssemblyError("invalid comparison operator")
+        }
+    }
+
+    private fun translateSquared(variable: IdentifierReference, dt: DataType) {
+        val asmVar = asmgen.asmVariableName(variable)
+        when(dt) {
+            DataType.BYTE, DataType.UBYTE -> {
+                asmgen.out("  lda  $asmVar")
+                asmgen.signExtendAYlsb(dt)
+                asmgen.out("  jsr  math.square")
+            }
+            DataType.UWORD, DataType.WORD -> {
+                asmgen.out("  lda  $asmVar |  ldy  $asmVar+1 |  jsr  math.square")
+            }
+            else -> throw AssemblyError("require integer dt for square")
+        }
+        asmgen.out("  sta  P8ESTACK_LO,x |  tya |  sta  P8ESTACK_HI,x |  dex")
+    }
+
+    private fun translateExpression(expr: PrefixExpression) {
+        translateExpressionInternal(expr.expression)
+        val itype = expr.inferType(program)
+        val type = itype.getOrElse { throw AssemblyError("unknown dt") }
+        when(expr.operator) {
+            "+" -> {}
+            "-" -> {
+                when(type) {
+                    in ByteDatatypes -> asmgen.out("  jsr  prog8_lib.neg_b")
+                    in WordDatatypes -> asmgen.out("  jsr  prog8_lib.neg_w")
+                    DataType.FLOAT -> asmgen.out("  jsr  floats.neg_f")
+                    else -> throw AssemblyError("weird type")
+                }
+            }
+            "~" -> {
+                when(type) {
+                    in ByteDatatypes ->
+                        asmgen.out("""
+                            lda  P8ESTACK_LO+1,x
+                            eor  #255
+                            sta  P8ESTACK_LO+1,x
+                            """)
+                    in WordDatatypes -> asmgen.out("  jsr  prog8_lib.inv_word")
+                    else -> throw AssemblyError("weird type")
+                }
+            }
+            "not" -> {
+                when(type) {
+                    in ByteDatatypes -> asmgen.out("  jsr  prog8_lib.not_byte")
+                    in WordDatatypes -> asmgen.out("  jsr  prog8_lib.not_word")
+                    else -> throw AssemblyError("weird type")
+                }
+            }
+            else -> throw AssemblyError("invalid prefix operator ${expr.operator}")
+        }
+    }
+
+    private fun translateExpression(arrayExpr: ArrayIndexedExpression) {
+        val elementIDt = arrayExpr.inferType(program)
+        if(!elementIDt.isKnown)
+            throw AssemblyError("unknown dt")
+        val elementDt = elementIDt.getOr(DataType.UNDEFINED)
+        val arrayVarName = asmgen.asmVariableName(arrayExpr.arrayvar)
+        val constIndexNum = arrayExpr.indexer.constIndex()
+        if(constIndexNum!=null) {
+            val indexValue = constIndexNum * program.memsizer.memorySize(elementDt)
+            when(elementDt) {
+                in ByteDatatypes -> {
+                    asmgen.out("  lda  $arrayVarName+$indexValue |  sta  P8ESTACK_LO,x |  dex")
+                }
+                in WordDatatypes -> {
+                    asmgen.out("  lda  $arrayVarName+$indexValue |  sta  P8ESTACK_LO,x |  lda  $arrayVarName+$indexValue+1 |  sta  P8ESTACK_HI,x |  dex")
+                }
+                DataType.FLOAT -> {
+                    asmgen.out("  lda  #<($arrayVarName+$indexValue) |  ldy  #>($arrayVarName+$indexValue) |  jsr  floats.push_float")
+                }
+                else -> throw AssemblyError("weird element type")
+            }
+        } else {
+            when(elementDt) {
+                in ByteDatatypes -> {
+                    asmgen.loadScaledArrayIndexIntoRegister(arrayExpr, elementDt, CpuRegister.Y)
+                    asmgen.out(" lda  $arrayVarName,y |  sta  P8ESTACK_LO,x |  dex")
+                }
+                in WordDatatypes -> {
+                    asmgen.loadScaledArrayIndexIntoRegister(arrayExpr, elementDt, CpuRegister.Y)
+                    asmgen.out(" lda  $arrayVarName,y |  sta  P8ESTACK_LO,x |  lda  $arrayVarName+1,y |  sta  P8ESTACK_HI,x |  dex")
+                }
+                DataType.FLOAT -> {
+                    asmgen.loadScaledArrayIndexIntoRegister(arrayExpr, elementDt, CpuRegister.A)
+                    asmgen.out("""
+                        ldy  #>$arrayVarName
+                        clc
+                        adc  #<$arrayVarName
+                        bcc  +
+                        iny
++                       jsr  floats.push_float""")
+                }
+                else -> throw AssemblyError("weird dt")
+            }
+
+        }
+    }
+
+    private fun translateBinaryOperatorBytes(operator: String, types: DataType) {
+        when(operator) {
+            "**" -> throw AssemblyError("** operator requires floats")
+            "*" -> asmgen.out("  jsr  prog8_lib.mul_byte")  //  the optimized routines should have been checked earlier
+            "/" -> asmgen.out(if(types==DataType.UBYTE) "  jsr  prog8_lib.idiv_ub" else "  jsr  prog8_lib.idiv_b")
+            "%" -> {
+                if(types==DataType.BYTE)
+                    throw AssemblyError("remainder of signed integers is not properly defined/implemented, use unsigned instead")
+                asmgen.out("  jsr prog8_lib.remainder_ub")
+            }
+            "+" -> asmgen.out("""
+                lda  P8ESTACK_LO+2,x
+                clc
+                adc  P8ESTACK_LO+1,x
+                inx
+                sta  P8ESTACK_LO+1,x
+                """)
+            "-" -> asmgen.out("""
+                lda  P8ESTACK_LO+2,x
+                sec
+                sbc  P8ESTACK_LO+1,x
+                inx
+                sta  P8ESTACK_LO+1,x
+                """)
+            "<<" -> asmgen.out("  jsr  prog8_lib.shiftleft_b")
+            ">>" -> asmgen.out("  jsr  prog8_lib.shiftright_b")
+            "<" -> asmgen.out(if(types==DataType.UBYTE) "  jsr  prog8_lib.less_ub" else "  jsr  prog8_lib.less_b")
+            ">" -> asmgen.out(if(types==DataType.UBYTE) "  jsr  prog8_lib.greater_ub" else "  jsr  prog8_lib.greater_b")
+            "<=" -> asmgen.out(if(types==DataType.UBYTE) "  jsr  prog8_lib.lesseq_ub" else "  jsr  prog8_lib.lesseq_b")
+            ">=" -> asmgen.out(if(types==DataType.UBYTE) "  jsr  prog8_lib.greatereq_ub" else "  jsr  prog8_lib.greatereq_b")
+            "==" -> asmgen.out("  jsr  prog8_lib.equal_b")
+            "!=" -> asmgen.out("  jsr  prog8_lib.notequal_b")
+            "&" -> asmgen.out("  jsr  prog8_lib.bitand_b")
+            "^" -> asmgen.out("  jsr  prog8_lib.bitxor_b")
+            "|" -> asmgen.out("  jsr  prog8_lib.bitor_b")
+            "and" -> asmgen.out("  jsr  prog8_lib.and_b")
+            "or" -> asmgen.out("  jsr  prog8_lib.or_b")
+            "xor" -> asmgen.out("  jsr  prog8_lib.xor_b")
+            else -> throw AssemblyError("invalid operator $operator")
+        }
+    }
+
+    private fun translateBinaryOperatorWords(operator: String, dt: DataType) {
+        when(operator) {
+            "**" -> throw AssemblyError("** operator requires floats")
+            "*" -> asmgen.out("  jsr  prog8_lib.mul_word")
+            "/" -> asmgen.out(if(dt==DataType.UWORD) "  jsr  prog8_lib.idiv_uw" else "  jsr  prog8_lib.idiv_w")
+            "%" -> {
+                if(dt==DataType.WORD)
+                    throw AssemblyError("remainder of signed integers is not properly defined/implemented, use unsigned instead")
+                asmgen.out("  jsr prog8_lib.remainder_uw")
+            }
+            "+" -> asmgen.out("  jsr  prog8_lib.add_w")
+            "-" -> asmgen.out("  jsr  prog8_lib.sub_w")
+            "<<" -> asmgen.out("  jsr  math.shift_left_w")
+            ">>" -> {
+                if(dt==DataType.UWORD)
+                    asmgen.out("  jsr  math.shift_right_uw")
+                else
+                    asmgen.out("  jsr  math.shift_right_w")
+            }
+            "<" -> asmgen.out(if(dt==DataType.UWORD) "  jsr  prog8_lib.less_uw" else "  jsr  prog8_lib.less_w")
+            ">" -> asmgen.out(if(dt==DataType.UWORD) "  jsr  prog8_lib.greater_uw" else "  jsr  prog8_lib.greater_w")
+            "<=" -> asmgen.out(if(dt==DataType.UWORD) "  jsr  prog8_lib.lesseq_uw" else "  jsr  prog8_lib.lesseq_w")
+            ">=" -> asmgen.out(if(dt==DataType.UWORD) "  jsr  prog8_lib.greatereq_uw" else "  jsr  prog8_lib.greatereq_w")
+            "==" -> asmgen.out("  jsr  prog8_lib.equal_w")
+            "!=" -> asmgen.out("  jsr  prog8_lib.notequal_w")
+            "&" -> asmgen.out("  jsr  prog8_lib.bitand_w")
+            "^" -> asmgen.out("  jsr  prog8_lib.bitxor_w")
+            "|" -> asmgen.out("  jsr  prog8_lib.bitor_w")
+            "and" -> asmgen.out("  jsr  prog8_lib.and_w")
+            "or" -> asmgen.out("  jsr  prog8_lib.or_w")
+            "xor" -> asmgen.out("  jsr  prog8_lib.xor_w")
+            else -> throw AssemblyError("invalid operator $operator")
+        }
+    }
+
+    private fun translateBinaryOperatorFloats(operator: String) {
+        when(operator) {
+            "**" -> asmgen.out(" jsr  floats.pow_f")
+            "*" -> asmgen.out("  jsr  floats.mul_f")
+            "/" -> asmgen.out("  jsr  floats.div_f")
+            "+" -> asmgen.out("  jsr  floats.add_f")
+            "-" -> asmgen.out("  jsr  floats.sub_f")
+            "<" -> asmgen.out("  jsr  floats.less_f")
+            ">" -> asmgen.out("  jsr  floats.greater_f")
+            "<=" -> asmgen.out("  jsr  floats.lesseq_f")
+            ">=" -> asmgen.out("  jsr  floats.greatereq_f")
+            "==" -> asmgen.out("  jsr  floats.equal_f")
+            "!=" -> asmgen.out("  jsr  floats.notequal_f")
+            "%", "<<", ">>", "&", "^", "|", "and", "or", "xor" -> throw AssemblyError("requires integer datatype")
+            else -> throw AssemblyError("invalid operator $operator")
+        }
+    }
+
+    private fun translateCompareStrings(s1: Expression, operator: String, s2: Expression) {
+        asmgen.assignExpressionToVariable(s1, "prog8_lib.strcmp_expression._arg_s1", DataType.UWORD, null)
+        asmgen.assignExpressionToVariable(s2, "prog8_lib.strcmp_expression._arg_s2", DataType.UWORD, null)
+        asmgen.out(" jsr  prog8_lib.strcmp_expression")    // result  of compare is in A
+        when(operator) {
+            "==" -> asmgen.out(" and  #1 |  eor  #1 |  sta  P8ESTACK_LO,x")
+            "!=" -> asmgen.out(" and  #1 |  sta  P8ESTACK_LO,x")
+            "<=" -> asmgen.out("""
+                bpl  +
+                lda  #1
+                bne  ++
++               lda  #0
++               sta  P8ESTACK_LO,x""")
+            ">=" -> asmgen.out("""
+                bmi  +
+                lda  #1
+                bne  ++
++               lda  #0
++               sta  P8ESTACK_LO,x""")
+            "<" -> asmgen.out("""
+                bmi  +
+                lda  #0
+                beq  ++
++               lda  #1
++               sta  P8ESTACK_LO,x""")
+            ">" -> asmgen.out("""
+                bpl  +
+                lda  #0
+                beq  ++
++               lda  #1
++               sta  P8ESTACK_LO,x""")
+        }
+        asmgen.out("  dex")
+    }
+}

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

@@ -0,0 +1,602 @@
+package prog8.codegen.cpu6502
+
+import com.github.michaelbull.result.fold
+import prog8.ast.Program
+import prog8.ast.base.ArrayToElementTypes
+import prog8.ast.base.DataType
+import prog8.ast.base.RegisterOrPair
+import prog8.ast.expressions.IdentifierReference
+import prog8.ast.expressions.RangeExpression
+import prog8.ast.statements.ForLoop
+import prog8.ast.toHex
+import prog8.compilerinterface.AssemblyError
+import prog8.compilerinterface.Zeropage
+import kotlin.math.absoluteValue
+
+internal class ForLoopsAsmGen(private val program: Program, private val asmgen: AsmGen, private val zeropage: Zeropage) {
+
+    internal fun translate(stmt: ForLoop) {
+        val iterableDt = stmt.iterable.inferType(program)
+        if(!iterableDt.isKnown)
+            throw AssemblyError("unknown dt")
+        when(stmt.iterable) {
+            is RangeExpression -> {
+                val range = (stmt.iterable as RangeExpression).toConstantIntegerRange()
+                if(range==null) {
+                    translateForOverNonconstRange(stmt, iterableDt.getOrElse { throw AssemblyError("unknown dt") }, stmt.iterable as RangeExpression)
+                } else {
+                    translateForOverConstRange(stmt, iterableDt.getOrElse { throw AssemblyError("unknown dt") }, range)
+                }
+            }
+            is IdentifierReference -> {
+                translateForOverIterableVar(stmt, iterableDt.getOrElse { throw AssemblyError("unknown dt") }, stmt.iterable as IdentifierReference)
+            }
+            else -> throw AssemblyError("can't iterate over ${stmt.iterable.javaClass} - should have been replaced by a variable")
+        }
+    }
+
+    private fun translateForOverNonconstRange(stmt: ForLoop, iterableDt: DataType, range: RangeExpression) {
+        val loopLabel = asmgen.makeLabel("for_loop")
+        val endLabel = asmgen.makeLabel("for_end")
+        val modifiedLabel = asmgen.makeLabel("for_modified")
+        val modifiedLabel2 = asmgen.makeLabel("for_modifiedb")
+        asmgen.loopEndLabels.push(endLabel)
+        val stepsize=range.step.constValue(program)!!.number.toInt()
+
+        if(stepsize < -1) {
+            val limit = range.to.constValue(program)?.number
+            if(limit==0.0)
+                throw AssemblyError("for unsigned loop variable it's not possible to count down with step != -1 from a non-const value to exactly zero due to value wrapping")
+        }
+
+        when(iterableDt) {
+            DataType.ARRAY_B, DataType.ARRAY_UB -> {
+                if (stepsize==1 || stepsize==-1) {
+
+                    // bytes array, step 1 or -1
+
+                    val incdec = if(stepsize==1) "inc" else "dec"
+                    // loop over byte range via loopvar
+                    val varname = asmgen.asmVariableName(stmt.loopVar)
+                    asmgen.assignExpressionToVariable(range.from, varname, ArrayToElementTypes.getValue(iterableDt), null)
+                    asmgen.assignExpressionToVariable(range.to, "$modifiedLabel+1", ArrayToElementTypes.getValue(iterableDt), null)
+                    asmgen.out(loopLabel)
+                    asmgen.translate(stmt.body)
+                    asmgen.out("""
+                        lda  $varname
+$modifiedLabel          cmp  #0         ; modified 
+                        beq  $endLabel
+                        $incdec  $varname""")
+                    asmgen.jmp(loopLabel)
+                    asmgen.out(endLabel)
+
+                } else {
+
+                    // bytes, step >= 2 or <= -2
+
+                    // loop over byte range via loopvar
+                    val varname = asmgen.asmVariableName(stmt.loopVar)
+                    asmgen.assignExpressionToVariable(range.from, varname, ArrayToElementTypes.getValue(iterableDt), null)
+                    asmgen.assignExpressionToVariable(range.to, "$modifiedLabel+1", ArrayToElementTypes.getValue(iterableDt), null)
+                    asmgen.out(loopLabel)
+                    asmgen.translate(stmt.body)
+                    if(stepsize>0) {
+                        asmgen.out("""
+                            lda  $varname
+                            clc
+                            adc  #$stepsize
+                            sta  $varname
+$modifiedLabel              cmp  #0    ; modified
+                            bmi  $loopLabel
+                            beq  $loopLabel""")
+                    } else {
+                        asmgen.out("""
+                            lda  $varname
+                            sec
+                            sbc  #${stepsize.absoluteValue}
+                            sta  $varname
+$modifiedLabel              cmp  #0     ; modified
+                            bpl  $loopLabel""")
+                    }
+                    asmgen.out(endLabel)
+                }
+            }
+            DataType.ARRAY_W, DataType.ARRAY_UW -> {
+                when {
+
+                    // words, step 1 or -1
+
+                    stepsize == 1 || stepsize == -1 -> {
+                        val varname = asmgen.asmVariableName(stmt.loopVar)
+                        assignLoopvar(stmt, range)
+                        asmgen.assignExpressionToRegister(range.to, RegisterOrPair.AY)
+                        asmgen.out("""
+                            sty  $modifiedLabel+1
+                            sta  $modifiedLabel2+1
+$loopLabel""")
+                        asmgen.translate(stmt.body)
+                        asmgen.out("""
+                lda  $varname+1
+$modifiedLabel  cmp  #0    ; modified 
+                bne  +
+                lda  $varname
+$modifiedLabel2 cmp  #0    ; modified 
+                beq  $endLabel""")
+                        if(stepsize==1) {
+                            asmgen.out("""
++               inc  $varname
+                bne  $loopLabel
+                inc  $varname+1""")
+                            asmgen.jmp(loopLabel)
+                        } else {
+                            asmgen.out("""
++               lda  $varname
+                bne  +
+                dec  $varname+1
++               dec  $varname""")
+                            asmgen.jmp(loopLabel)
+                        }
+                        asmgen.out(endLabel)
+                    }
+                    stepsize > 0 -> {
+
+                        // (u)words, step >= 2
+                        val varname = asmgen.asmVariableName(stmt.loopVar)
+                        assignLoopvar(stmt, range)
+                        asmgen.assignExpressionToRegister(range.to, RegisterOrPair.AY)
+                        asmgen.out("""
+                            sty  $modifiedLabel+1
+                            sta  $modifiedLabel2+1
+$loopLabel""")
+                        asmgen.translate(stmt.body)
+
+                        if (iterableDt == DataType.ARRAY_UW) {
+                            asmgen.out("""
+                lda  $varname
+                clc
+                adc  #<$stepsize
+                sta  $varname
+                lda  $varname+1
+                adc  #>$stepsize
+                sta  $varname+1
+$modifiedLabel  cmp  #0     ; modified
+                bcc  $loopLabel
+                bne  $endLabel
+$modifiedLabel2 lda  #0     ; modified
+                cmp  $varname
+                bcc  $endLabel
+                bcs  $loopLabel
+$endLabel""")
+                        } else {
+                            asmgen.out("""
+                lda  $varname
+                clc
+                adc  #<$stepsize
+                sta  $varname
+                lda  $varname+1
+                adc  #>$stepsize
+                sta  $varname+1
+$modifiedLabel2 lda  #0   ; modified
+                cmp  $varname
+$modifiedLabel  lda  #0   ; modified
+                sbc  $varname+1
+                bvc  +
+                eor  #$80
++               bpl  $loopLabel                
+$endLabel""")
+                        }
+                    }
+                    else -> {
+
+                        // (u)words, step <= -2
+                        val varname = asmgen.asmVariableName(stmt.loopVar)
+                        assignLoopvar(stmt, range)
+                        asmgen.assignExpressionToRegister(range.to, RegisterOrPair.AY)
+                        asmgen.out("""
+                            sty  $modifiedLabel+1
+                            sta  $modifiedLabel2+1
+$loopLabel""")
+                        asmgen.translate(stmt.body)
+
+                        if(iterableDt==DataType.ARRAY_UW) {
+                            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  $varname
+                sec
+                sbc  #<${stepsize.absoluteValue}
+                sta  $varname
+                pha
+                lda  $varname+1
+                sbc  #>${stepsize.absoluteValue}
+                sta  $varname+1
+                pla
+$modifiedLabel2 cmp  #0    ; modified 
+                lda  $varname+1
+$modifiedLabel  sbc  #0    ; modified
+                bvc  +
+                eor  #$80
++               bpl  $loopLabel                
+$endLabel""")
+                        }
+                    }
+                }
+            }
+            else -> throw AssemblyError("range expression can only be byte or word")
+        }
+
+        asmgen.loopEndLabels.pop()
+    }
+
+    private fun translateForOverIterableVar(stmt: ForLoop, iterableDt: DataType, ident: IdentifierReference) {
+        val loopLabel = asmgen.makeLabel("for_loop")
+        val endLabel = asmgen.makeLabel("for_end")
+        asmgen.loopEndLabels.push(endLabel)
+        val iterableName = asmgen.asmVariableName(ident)
+        val decl = ident.targetVarDecl(program)!!
+        when(iterableDt) {
+            DataType.STR -> {
+                asmgen.out("""
+                    lda  #<$iterableName
+                    ldy  #>$iterableName
+                    sta  $loopLabel+1
+                    sty  $loopLabel+2
+$loopLabel          lda  ${65535.toHex()}       ; modified
+                    beq  $endLabel
+                    sta  ${asmgen.asmVariableName(stmt.loopVar)}""")
+                asmgen.translate(stmt.body)
+                asmgen.out("""
+                    inc  $loopLabel+1
+                    bne  $loopLabel
+                    inc  $loopLabel+2
+                    bne  $loopLabel
+$endLabel""")
+            }
+            DataType.ARRAY_UB, DataType.ARRAY_B -> {
+                val length = decl.arraysize!!.constIndex()!!
+                val indexVar = asmgen.makeLabel("for_index")
+                asmgen.out("""
+                    ldy  #0
+$loopLabel          sty  $indexVar
+                    lda  $iterableName,y
+                    sta  ${asmgen.asmVariableName(stmt.loopVar)}""")
+                asmgen.translate(stmt.body)
+                if(length<=255) {
+                    asmgen.out("""
+                        ldy  $indexVar
+                        iny
+                        cpy  #$length
+                        beq  $endLabel
+                        bne  $loopLabel""")
+                } else {
+                    // length is 256
+                    asmgen.out("""
+                        ldy  $indexVar
+                        iny
+                        bne  $loopLabel
+                        beq  $endLabel""")
+                }
+                if(length>=16) {
+                    // allocate index var on ZP if possible
+                    val result = zeropage.allocate(listOf(indexVar), DataType.UBYTE, stmt.definingScope, null, null, stmt.position, asmgen.errors)
+                    result.fold(
+                        success = { (address,_)-> asmgen.out("""$indexVar = $address  ; auto zp UBYTE""") },
+                        failure = { asmgen.out("$indexVar    .byte  0") }
+                    )
+                } else {
+                    asmgen.out("$indexVar    .byte  0")
+                }
+                asmgen.out(endLabel)
+            }
+            DataType.ARRAY_W, DataType.ARRAY_UW -> {
+                val length = decl.arraysize!!.constIndex()!! * 2
+                val indexVar = asmgen.makeLabel("for_index")
+                val loopvarName = asmgen.asmVariableName(stmt.loopVar)
+                asmgen.out("""
+                    ldy  #0
+$loopLabel          sty  $indexVar
+                    lda  $iterableName,y
+                    sta  $loopvarName
+                    lda  $iterableName+1,y
+                    sta  $loopvarName+1""")
+                asmgen.translate(stmt.body)
+                if(length<=127) {
+                    asmgen.out("""
+                        ldy  $indexVar
+                        iny
+                        iny
+                        cpy  #$length
+                        beq  $endLabel
+                        bne  $loopLabel""")
+                } else {
+                    // length is 128 words, 256 bytes
+                    asmgen.out("""
+                        ldy  $indexVar
+                        iny
+                        iny
+                        bne  $loopLabel
+                        beq  $endLabel""")
+                }
+                if(length>=16) {
+                    // allocate index var on ZP if possible
+                    val result = zeropage.allocate(listOf(indexVar), DataType.UBYTE, stmt.definingScope, null, null, stmt.position, asmgen.errors)
+                    result.fold(
+                        success = { (address,_)-> asmgen.out("""$indexVar = $address  ; auto zp UBYTE""") },
+                        failure = { asmgen.out("$indexVar    .byte  0") }
+                    )
+                } else {
+                    asmgen.out("$indexVar    .byte  0")
+                }
+                asmgen.out(endLabel)
+            }
+            DataType.ARRAY_F -> {
+                throw AssemblyError("for loop with floating point variables is not supported")
+            }
+            else -> throw AssemblyError("can't iterate over $iterableDt")
+        }
+        asmgen.loopEndLabels.pop()
+    }
+
+    private fun translateForOverConstRange(stmt: ForLoop, iterableDt: DataType, range: IntProgression) {
+        if (range.isEmpty() || range.step==0)
+            throw AssemblyError("empty range or step 0")
+        if(iterableDt==DataType.ARRAY_B || iterableDt==DataType.ARRAY_UB) {
+            if(range.step==1 && range.last>range.first) return translateForSimpleByteRangeAsc(stmt, range)
+            if(range.step==-1 && range.last<range.first) return translateForSimpleByteRangeDesc(stmt, range)
+        }
+        else if(iterableDt==DataType.ARRAY_W || iterableDt==DataType.ARRAY_UW) {
+            if(range.step==1 && range.last>range.first) return translateForSimpleWordRangeAsc(stmt, range)
+            if(range.step==-1 && range.last<range.first) return translateForSimpleWordRangeDesc(stmt, range)
+        }
+
+        // not one of the easy cases, generate more complex code...
+        val loopLabel = asmgen.makeLabel("for_loop")
+        val endLabel = asmgen.makeLabel("for_end")
+        asmgen.loopEndLabels.push(endLabel)
+        when(iterableDt) {
+            DataType.ARRAY_B, DataType.ARRAY_UB -> {
+                // loop over byte range via loopvar, step >= 2 or <= -2
+                val varname = asmgen.asmVariableName(stmt.loopVar)
+                asmgen.out("""
+                            lda  #${range.first}
+                            sta  $varname
+$loopLabel""")
+                asmgen.translate(stmt.body)
+                when (range.step) {
+                    0, 1, -1 -> {
+                        throw AssemblyError("step 0, 1 and -1 should have been handled specifically  $stmt")
+                    }
+                    2 -> {
+                        if(range.last==255 || range.last==254) {
+                            asmgen.out("""
+                                inc  $varname
+                                beq  $endLabel
+                                inc  $varname
+                                bne  $loopLabel""")
+                        } else {
+                            asmgen.out("""
+                                inc  $varname
+                                inc  $varname
+                                lda  $varname
+                                cmp  #${range.last+2}
+                                bne  $loopLabel""")
+                        }
+                    }
+                    -2 -> {
+                        when (range.last) {
+                            0 -> {
+                                asmgen.out("""
+                                    lda  $varname
+                                    beq  $endLabel
+                                    dec  $varname
+                                    dec  $varname""")
+                                asmgen.jmp(loopLabel)
+                            }
+                            1 -> asmgen.out("""
+                                    dec  $varname
+                                    beq  $endLabel
+                                    dec  $varname
+                                    bne  $loopLabel""")
+                            else -> asmgen.out("""
+                                    dec  $varname
+                                    dec  $varname
+                                    lda  $varname
+                                    cmp  #${range.last-2}
+                                    bne  $loopLabel""")
+                        }
+                    }
+                    else -> {
+                        // step <= -3 or >= 3
+                        asmgen.out("""
+                            lda  $varname
+                            cmp  #${range.last}
+                            beq  $endLabel
+                            clc
+                            adc  #${range.step}
+                            sta  $varname""")
+                        asmgen.jmp(loopLabel)
+                    }
+                }
+                asmgen.out(endLabel)
+            }
+            DataType.ARRAY_W, DataType.ARRAY_UW -> {
+                // loop over word range via loopvar, step >= 2 or <= -2
+                val varname = asmgen.asmVariableName(stmt.loopVar)
+                when (range.step) {
+                    0, 1, -1 -> {
+                        throw AssemblyError("step 0, 1 and -1 should have been handled specifically  $stmt")
+                    }
+                    else -> {
+                        // word, step >= 2 or <= -2
+                        // note: range.last has already been adjusted by kotlin itself to actually be the last value of the sequence
+                        asmgen.out("""
+                            lda  #<${range.first}
+                            ldy  #>${range.first}
+                            sta  $varname
+                            sty  $varname+1
+$loopLabel""")
+                        asmgen.translate(stmt.body)
+                        asmgen.out("""
+                            lda  $varname
+                            cmp  #<${range.last}
+                            bne  +
+                            lda  $varname+1
+                            cmp  #>${range.last}
+                            bne  +
+                            beq  $endLabel
++                           lda  $varname
+                            clc
+                            adc  #<${range.step}
+                            sta  $varname
+                            lda  $varname+1
+                            adc  #>${range.step}
+                            sta  $varname+1""")
+                        asmgen.jmp(loopLabel)
+                        asmgen.out(endLabel)
+                    }
+                }
+            }
+            else -> throw AssemblyError("range expression can only be byte or word")
+        }
+        asmgen.loopEndLabels.pop()
+    }
+
+    private fun translateForSimpleByteRangeAsc(stmt: ForLoop, range: IntProgression) {
+        val loopLabel = asmgen.makeLabel("for_loop")
+        val endLabel = asmgen.makeLabel("for_end")
+        asmgen.loopEndLabels.push(endLabel)
+        val varname = asmgen.asmVariableName(stmt.loopVar)
+        asmgen.out("""
+                lda  #${range.first}
+                sta  $varname
+$loopLabel""")
+        asmgen.translate(stmt.body)
+        if (range.last == 255) {
+            asmgen.out("""
+                inc  $varname
+                bne  $loopLabel
+$endLabel""")
+        } else {
+            asmgen.out("""
+                inc  $varname
+                lda  $varname
+                cmp  #${range.last+1}
+                bne  $loopLabel
+$endLabel""")
+        }
+        asmgen.loopEndLabels.pop()
+    }
+
+    private fun translateForSimpleByteRangeDesc(stmt: ForLoop, range: IntProgression) {
+        val loopLabel = asmgen.makeLabel("for_loop")
+        val endLabel = asmgen.makeLabel("for_end")
+        asmgen.loopEndLabels.push(endLabel)
+        val varname = asmgen.asmVariableName(stmt.loopVar)
+        asmgen.out("""
+                    lda  #${range.first}
+                    sta  $varname
+$loopLabel""")
+        asmgen.translate(stmt.body)
+        when (range.last) {
+            0 -> {
+                asmgen.out("""
+                    lda  $varname
+                    beq  $endLabel
+                    dec  $varname""")
+                asmgen.jmp(loopLabel)
+                asmgen.out(endLabel)
+            }
+            1 -> {
+                asmgen.out("""
+                    dec  $varname
+                    bne  $loopLabel
+$endLabel""")
+            }
+            else -> {
+                asmgen.out("""
+                    dec  $varname
+                    lda  $varname
+                    cmp  #${range.last-1}
+                    bne  $loopLabel
+$endLabel""")
+            }
+        }
+        asmgen.loopEndLabels.pop()
+    }
+
+    private fun translateForSimpleWordRangeAsc(stmt: ForLoop, range: IntProgression) {
+        val loopLabel = asmgen.makeLabel("for_loop")
+        val endLabel = asmgen.makeLabel("for_end")
+        asmgen.loopEndLabels.push(endLabel)
+        val varname = asmgen.asmVariableName(stmt.loopVar)
+        asmgen.out("""
+            lda  #<${range.first}
+            ldy  #>${range.first}
+            sta  $varname
+            sty  $varname+1
+$loopLabel""")
+        asmgen.translate(stmt.body)
+        asmgen.out("""
+            lda  $varname
+            cmp  #<${range.last}
+            bne  +
+            lda  $varname+1
+            cmp  #>${range.last}
+            beq  $endLabel
++           inc  $varname
+            bne  $loopLabel
+            inc  $varname+1""")
+        asmgen.jmp(loopLabel)
+        asmgen.out(endLabel)
+        asmgen.loopEndLabels.pop()
+    }
+
+    private fun translateForSimpleWordRangeDesc(stmt: ForLoop, range: IntProgression) {
+        val loopLabel = asmgen.makeLabel("for_loop")
+        val endLabel = asmgen.makeLabel("for_end")
+        asmgen.loopEndLabels.push(endLabel)
+        val varname = asmgen.asmVariableName(stmt.loopVar)
+        asmgen.out("""
+            lda  #<${range.first}
+            ldy  #>${range.first}
+            sta  $varname
+            sty  $varname+1
+$loopLabel""")
+        asmgen.translate(stmt.body)
+        asmgen.out("""
+            lda  $varname
+            cmp  #<${range.last}
+            bne  +
+            lda  $varname+1
+            cmp  #>${range.last}
+            beq  $endLabel
++           lda  $varname
+            bne  +
+            dec  $varname+1
++           dec  $varname""")
+        asmgen.jmp(loopLabel)
+        asmgen.out(endLabel)
+        asmgen.loopEndLabels.pop()
+    }
+
+    private fun assignLoopvar(stmt: ForLoop, range: RangeExpression) =
+        asmgen.assignExpressionToVariable(
+            range.from,
+            asmgen.asmVariableName(stmt.loopVar),
+            stmt.loopVarDt(program).getOrElse { throw AssemblyError("unknown dt") },
+            stmt.definingSubroutine)
+}

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

@@ -0,0 +1,275 @@
+package prog8.codegen.cpu6502
+
+import prog8.ast.IFunctionCall
+import prog8.ast.Node
+import prog8.ast.Program
+import prog8.ast.base.*
+import prog8.ast.expressions.AddressOf
+import prog8.ast.expressions.Expression
+import prog8.ast.expressions.IdentifierReference
+import prog8.ast.expressions.NumericLiteral
+import prog8.ast.statements.*
+import prog8.codegen.cpu6502.assignment.AsmAssignSource
+import prog8.codegen.cpu6502.assignment.AsmAssignTarget
+import prog8.codegen.cpu6502.assignment.AsmAssignment
+import prog8.codegen.cpu6502.assignment.TargetStorageKind
+import prog8.compilerinterface.AssemblyError
+
+
+internal class FunctionCallAsmGen(private val program: Program, private val asmgen: AsmGen) {
+
+    internal fun translateFunctionCallStatement(stmt: FunctionCallStatement) {
+        saveXbeforeCall(stmt)
+        translateFunctionCall(stmt, false)
+        restoreXafterCall(stmt)
+        // just ignore any result values from the function call.
+    }
+
+    internal fun saveXbeforeCall(stmt: IFunctionCall) {
+        val sub = stmt.target.targetSubroutine(program) ?: throw AssemblyError("undefined subroutine ${stmt.target}")
+        if(sub.shouldSaveX()) {
+            val regSaveOnStack = sub.asmAddress==null       // rom-routines don't require registers to be saved on stack, normal subroutines do because they can contain nested calls
+            if(regSaveOnStack)
+                asmgen.saveRegisterStack(CpuRegister.X, sub.shouldKeepA().saveOnEntry)
+            else
+                asmgen.saveRegisterLocal(CpuRegister.X, (stmt as Node).definingSubroutine!!)
+        }
+    }
+
+    internal fun saveXbeforeCall(gosub: GoSub) {
+        val sub = gosub.identifier?.targetSubroutine(program)
+        if(sub?.shouldSaveX()==true) {
+            val regSaveOnStack = sub.asmAddress==null       // rom-routines don't require registers to be saved on stack, normal subroutines do because they can contain nested calls
+            if(regSaveOnStack)
+                asmgen.saveRegisterStack(CpuRegister.X, sub.shouldKeepA().saveOnEntry)
+            else
+                asmgen.saveRegisterLocal(CpuRegister.X, gosub.definingSubroutine!!)
+        }
+    }
+
+    internal fun restoreXafterCall(stmt: IFunctionCall) {
+        val sub = stmt.target.targetSubroutine(program) ?: throw AssemblyError("undefined subroutine ${stmt.target}")
+        if(sub.shouldSaveX()) {
+            val regSaveOnStack = sub.asmAddress==null       // rom-routines don't require registers to be saved on stack, normal subroutines do because they can contain nested calls
+            if(regSaveOnStack)
+                asmgen.restoreRegisterStack(CpuRegister.X, sub.shouldKeepA().saveOnReturn)
+            else
+                asmgen.restoreRegisterLocal(CpuRegister.X)
+        }
+    }
+
+    internal fun restoreXafterCall(gosub: GoSub) {
+        val sub = gosub.identifier?.targetSubroutine(program)
+        if(sub?.shouldSaveX()==true) {
+            val regSaveOnStack = sub.asmAddress==null       // rom-routines don't require registers to be saved on stack, normal subroutines do because they can contain nested calls
+            if(regSaveOnStack)
+                asmgen.restoreRegisterStack(CpuRegister.X, sub.shouldKeepA().saveOnReturn)
+            else
+                asmgen.restoreRegisterLocal(CpuRegister.X)
+        }
+    }
+
+    internal fun optimizeIntArgsViaRegisters(sub: Subroutine) =
+        (sub.parameters.size==1 && sub.parameters[0].type in IntegerDatatypes)
+                || (sub.parameters.size==2 && sub.parameters[0].type in ByteDatatypes && sub.parameters[1].type in ByteDatatypes)
+
+    internal fun translateFunctionCall(call: IFunctionCall, isExpression: Boolean) {
+        // Output only the code to set up the parameters and perform the actual call
+        // NOTE: does NOT output the code to deal with the result values!
+        // NOTE: does NOT output code to save/restore the X register for this call! Every caller should deal with this in their own way!!
+        //       (you can use subroutine.shouldSaveX() and saveX()/restoreX() routines as a help for this)
+
+        val sub = call.target.targetSubroutine(program) ?: throw AssemblyError("undefined subroutine ${call.target}")
+        val subAsmName = asmgen.asmSymbolName(call.target)
+
+        if(!isExpression && !sub.isAsmSubroutine) {
+            if(!optimizeIntArgsViaRegisters(sub))
+                throw AssemblyError("functioncall statements to non-asmsub should have been replaced by GoSub $call")
+        }
+
+        if(sub.isAsmSubroutine) {
+            argumentsViaRegisters(sub, call)
+            if (sub.inline && asmgen.options.optimize) {
+                // inline the subroutine.
+                // we do this by copying the subroutine's statements at the call site.
+                // NOTE: *if* there is a return statement, it will be the only one, and the very last statement of the subroutine
+                // (this condition has been enforced by an ast check earlier)
+                asmgen.out("  \t; inlined routine follows: ${sub.name}")
+                sub.statements.forEach { asmgen.translate(it as InlineAssembly) }
+                asmgen.out("  \t; inlined routine end: ${sub.name}")
+            } else {
+                asmgen.out("  jsr  $subAsmName")
+            }
+        }
+        else {
+            if(sub.inline)
+                throw AssemblyError("can only reliably inline asmsub routines at this time")
+
+            if(optimizeIntArgsViaRegisters(sub)) {
+                if(sub.parameters.size==1) {
+                    val register = if (sub.parameters[0].type in ByteDatatypes) RegisterOrPair.A else RegisterOrPair.AY
+                    argumentViaRegister(sub, IndexedValue(0, sub.parameters[0]), call.args[0], register)
+                } else {
+                    // 2 byte params, second in Y, first in A
+                    argumentViaRegister(sub, IndexedValue(0, sub.parameters[0]), call.args[0], RegisterOrPair.A)
+                    if(!call.args[1].isSimple)
+                        asmgen.out("  pha")
+                    argumentViaRegister(sub, IndexedValue(1, sub.parameters[1]), call.args[1], RegisterOrPair.Y)
+                    if(!call.args[1].isSimple)
+                        asmgen.out("  pla")
+                }
+            } else {
+                // arguments via variables
+                for(arg in sub.parameters.withIndex().zip(call.args))
+                    argumentViaVariable(sub, arg.first.value, arg.second)
+            }
+            asmgen.out("  jsr  $subAsmName")
+        }
+
+        // remember: dealing with the X register and/or dealing with return values is the responsibility of the caller
+    }
+
+    private fun argumentsViaRegisters(sub: Subroutine, call: IFunctionCall) {
+        if(sub.parameters.size==1) {
+            argumentViaRegister(sub, IndexedValue(0, sub.parameters.single()), call.args[0])
+        } else {
+            if(asmgen.asmsubArgsHaveRegisterClobberRisk(call.args, sub.asmParameterRegisters)) {
+                registerArgsViaCpuStackEvaluation(call, sub)
+            } else {
+                asmgen.asmsubArgsEvalOrder(sub).forEach {
+                    val param = sub.parameters[it]
+                    val arg = call.args[it]
+                    argumentViaRegister(sub, IndexedValue(it, param), arg)
+                }
+            }
+        }
+    }
+
+    private fun registerArgsViaCpuStackEvaluation(call: IFunctionCall, callee: Subroutine) {
+        // this is called when one or more of the arguments are 'complex' and
+        // cannot be assigned to a register easily or risk clobbering other registers.
+
+        require(callee.isAsmSubroutine)
+        if(callee.parameters.isEmpty())
+            return
+
+        // use the cpu hardware stack as intermediate storage for the arguments.
+        val argOrder = asmgen.options.compTarget.asmsubArgsEvalOrder(callee)
+        argOrder.reversed().forEach {
+            asmgen.pushCpuStack(callee.parameters[it].type, call.args[it])
+        }
+        argOrder.forEach {
+            val param = callee.parameters[it]
+            val targetVar = callee.searchAsmParameter(param.name)!!
+            asmgen.popCpuStack(param.type, targetVar, (call as Node).definingSubroutine)
+        }
+    }
+
+    private fun argumentViaVariable(sub: Subroutine, parameter: SubroutineParameter, value: Expression) {
+        // pass parameter via a regular variable (not via registers)
+        val valueIDt = value.inferType(program)
+        val valueDt = valueIDt.getOrElse { throw AssemblyError("unknown dt") }
+        if(!isArgumentTypeCompatible(valueDt, parameter.type))
+            throw AssemblyError("argument type incompatible")
+
+        val varName = asmgen.asmVariableName(sub.scopedName + parameter.name)
+        asmgen.assignExpressionToVariable(value, varName, parameter.type, sub)
+    }
+
+    private fun argumentViaRegister(sub: Subroutine, parameter: IndexedValue<SubroutineParameter>, value: Expression, registerOverride: RegisterOrPair? = null) {
+        // pass argument via a register parameter
+        val valueIDt = value.inferType(program)
+        val valueDt = valueIDt.getOrElse { throw AssemblyError("unknown dt") }
+        if(!isArgumentTypeCompatible(valueDt, parameter.value.type))
+            throw AssemblyError("argument type incompatible")
+
+        val paramRegister = if(registerOverride==null) sub.asmParameterRegisters[parameter.index] else RegisterOrStatusflag(registerOverride, null)
+        val statusflag = paramRegister.statusflag
+        val register = paramRegister.registerOrPair
+        val requiredDt = parameter.value.type
+        if(requiredDt!=valueDt) {
+            if(valueDt largerThan requiredDt)
+                throw AssemblyError("can only convert byte values to word param types")
+        }
+        if (statusflag!=null) {
+            if(requiredDt!=valueDt)
+                throw AssemblyError("for statusflag, byte value is required")
+            if (statusflag == Statusflag.Pc) {
+                // this param needs to be set last, right before the jsr
+                // for now, this is already enforced on the subroutine definition by the Ast Checker
+                when(value) {
+                    is NumericLiteral -> {
+                        val carrySet = value.number.toInt() != 0
+                        asmgen.out(if(carrySet) "  sec" else "  clc")
+                    }
+                    is IdentifierReference -> {
+                        val sourceName = asmgen.asmVariableName(value)
+                        asmgen.out("""
+                            pha
+                            clc
+                            lda  $sourceName
+                            beq  +
+                            sec  
++                           pla""")
+                    }
+                    else -> {
+                        asmgen.assignExpressionToRegister(value, RegisterOrPair.A)
+                        asmgen.out("""
+                            beq  +
+                            sec
+                            bcs  ++
++                           clc
++""")
+                    }
+                }
+            } else throw AssemblyError("can only use Carry as status flag parameter")
+        }
+        else {
+            // via register or register pair
+            register!!
+            if(requiredDt largerThan valueDt) {
+                // we need to sign extend the source, do this via temporary word variable
+                asmgen.assignExpressionToVariable(value, "P8ZP_SCRATCH_W1", DataType.UBYTE, sub)
+                asmgen.signExtendVariableLsb("P8ZP_SCRATCH_W1", valueDt)
+                asmgen.assignVariableToRegister("P8ZP_SCRATCH_W1", register)
+            } else {
+                val target: AsmAssignTarget =
+                    if(parameter.value.type in ByteDatatypes && (register==RegisterOrPair.AX || register == RegisterOrPair.AY || register==RegisterOrPair.XY || register in Cx16VirtualRegisters))
+                        AsmAssignTarget(TargetStorageKind.REGISTER, program, asmgen, parameter.value.type, sub, register = register)
+                    else {
+                        val signed = parameter.value.type == DataType.BYTE || parameter.value.type == DataType.WORD
+                        AsmAssignTarget.fromRegisters(register, signed, sub, program, asmgen)
+                    }
+                val src = if(valueDt in PassByReferenceDatatypes) {
+                    if(value is IdentifierReference) {
+                        val addr = AddressOf(value, Position.DUMMY)
+                        AsmAssignSource.fromAstSource(addr, program, asmgen).adjustSignedUnsigned(target)
+                    } else {
+                        AsmAssignSource.fromAstSource(value, program, asmgen).adjustSignedUnsigned(target)
+                    }
+                } else {
+                    AsmAssignSource.fromAstSource(value, program, asmgen).adjustSignedUnsigned(target)
+                }
+                asmgen.translateNormalAssignment(AsmAssignment(src, target, false, program.memsizer, Position.DUMMY))
+            }
+        }
+    }
+
+    private fun isArgumentTypeCompatible(argType: DataType, paramType: DataType): Boolean {
+        if(argType isAssignableTo paramType)
+            return true
+        if(argType in ByteDatatypes && paramType in ByteDatatypes)
+            return true
+        if(argType in WordDatatypes && paramType in WordDatatypes)
+            return true
+
+        // we have a special rule for some types.
+        // strings are assignable to UWORD, for example, and vice versa
+        if(argType==DataType.STR && paramType==DataType.UWORD)
+            return true
+        if(argType==DataType.UWORD && paramType == DataType.STR)
+            return true
+
+        return false
+    }
+}

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

@@ -0,0 +1,128 @@
+package prog8.codegen.cpu6502
+
+import prog8.ast.Program
+import prog8.ast.base.*
+import prog8.ast.expressions.IdentifierReference
+import prog8.ast.expressions.NumericLiteral
+import prog8.ast.statements.PostIncrDecr
+import prog8.ast.toHex
+import prog8.compilerinterface.AssemblyError
+
+
+internal class PostIncrDecrAsmGen(private val program: Program, private val asmgen: AsmGen) {
+    internal fun translate(stmt: PostIncrDecr) {
+        val incr = stmt.operator=="++"
+        val targetIdent = stmt.target.identifier
+        val targetMemory = stmt.target.memoryAddress
+        val targetArrayIdx = stmt.target.arrayindexed
+        val scope = stmt.definingSubroutine
+        when {
+            targetIdent!=null -> {
+                val what = asmgen.asmVariableName(targetIdent)
+                when (stmt.target.inferType(program).getOr(DataType.UNDEFINED)) {
+                    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.addressExpression) {
+                    is NumericLiteral -> {
+                        val what = addressExpr.number.toHex()
+                        asmgen.out(if(incr) "  inc  $what" else "  dec  $what")
+                    }
+                    is IdentifierReference -> {
+                        val what = asmgen.asmVariableName(addressExpr)
+                        asmgen.out("  lda  $what |  sta  (+) +1 |  lda  $what+1 |  sta  (+) +2")
+                        if(incr)
+                            asmgen.out("+\tinc  ${'$'}ffff\t; modified")
+                        else
+                            asmgen.out("+\tdec  ${'$'}ffff\t; modified")
+                    }
+                    else -> {
+                        asmgen.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.arrayvar)
+                val elementDt = targetArrayIdx.inferType(program).getOr(DataType.UNDEFINED)
+                val constIndex = targetArrayIdx.indexer.constIndex()
+                if(constIndex!=null) {
+                    val indexValue = constIndex * program.memsizer.memorySize(elementDt)
+                    when(elementDt) {
+                        in ByteDatatypes -> asmgen.out(if (incr) "  inc  $asmArrayvarname+$indexValue" else "  dec  $asmArrayvarname+$indexValue")
+                        in WordDatatypes -> {
+                            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.A)
+                    asmgen.saveRegisterLocal(CpuRegister.X, scope!!)
+                    asmgen.out("  tax")
+                    when(elementDt) {
+                        in ByteDatatypes -> {
+                            asmgen.out(if(incr) "  inc  $asmArrayvarname,x" else "  dec  $asmArrayvarname,x")
+                        }
+                        in WordDatatypes -> {
+                            if(incr)
+                                asmgen.out(" inc  $asmArrayvarname,x |  bne  + |  inc  $asmArrayvarname+1,x |+")
+                            else
+                                asmgen.out("""
+    lda  $asmArrayvarname,x
+    bne  +
+    dec  $asmArrayvarname+1,x
++       dec  $asmArrayvarname,x 
+""")
+                        }
+                        DataType.FLOAT -> {
+                            asmgen.out("""
+                    ldy  #>$asmArrayvarname
+                    clc
+                    adc  #<$asmArrayvarname
+                    bcc  +
+                    iny
++                       jsr  floats.inc_var_f""")
+                        }
+                        else -> throw AssemblyError("weird array elt dt")
+                    }
+                    asmgen.restoreRegisterLocal(CpuRegister.X)
+                }
+            }
+        }
+    }
+}

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

@@ -0,0 +1,623 @@
+package prog8.codegen.cpu6502
+
+import prog8.ast.INameScope
+import prog8.ast.Program
+import prog8.ast.antlr.escape
+import prog8.ast.base.*
+import prog8.ast.expressions.*
+import prog8.ast.statements.*
+import prog8.ast.toHex
+import prog8.codegen.cpu6502.assignment.AsmAssignTarget
+import prog8.codegen.cpu6502.assignment.TargetStorageKind
+import prog8.compilerinterface.*
+import java.time.LocalDate
+import java.time.LocalDateTime
+import kotlin.math.absoluteValue
+
+/**
+ * Generates the main parts of the program:
+ *  - entry/exit code
+ *  - initialization routines
+ *  - blocks
+ *  - subroutines
+ *  - all variables (note: VarDecl ast nodes are *NOT* used anymore for this! now uses IVariablesAndConsts data tables!)
+ */
+internal class ProgramAndVarsGen(
+    val program: Program,
+    val variables: IVariablesAndConsts,
+    val options: CompilationOptions,
+    val errors: IErrorReporter,
+    private val functioncallAsmGen: FunctionCallAsmGen,
+    private val asmgen: AsmGen,
+    private val allocator: VariableAllocator,
+    private val zeropage: Zeropage
+) {
+    private val compTarget = options.compTarget
+    private val callGraph = CallGraph(program, true)
+    private val blockVariableInitializers = program.allBlocks.associateWith { it.statements.filterIsInstance<Assignment>() }
+
+    internal fun generate() {
+        val allInitializers = blockVariableInitializers.asSequence().flatMap { it.value }
+        require(allInitializers.all { it.origin==AssignmentOrigin.VARINIT }) {"all block-level assignments must be a variable initializer"}
+
+        allocator.allocateZeropageVariables()
+
+        header()
+        val allBlocks = program.allBlocks
+        if(allBlocks.first().name != "main")
+            throw AssemblyError("first block should be 'main'")
+
+        if(errors.noErrors())  {
+            program.allBlocks.forEach { block2asm(it) }
+            memorySlabs()
+            footer()
+        }
+    }
+
+    private fun header() {
+        val ourName = this.javaClass.name
+        val cpu = when(compTarget.machine.cpu) {
+            CpuType.CPU6502 -> "6502"
+            CpuType.CPU65c02 -> "w65c02"
+            else -> "unsupported"
+        }
+
+        asmgen.out("; $cpu assembly code for '${program.name}'")
+        asmgen.out("; generated by $ourName on ${LocalDateTime.now().withNano(0)}")
+        asmgen.out("; assembler syntax is for the 64tasm cross-assembler")
+        asmgen.out("; output options: output=${options.output} launcher=${options.launcher} zp=${options.zeropage}")
+        asmgen.out("")
+        asmgen.out(".cpu  '$cpu'\n.enc  'none'\n")
+
+        program.actualLoadAddress = program.definedLoadAddress
+        if (program.actualLoadAddress == 0u) {
+            when(options.output) {
+                OutputType.RAW -> {
+                    errors.err("load address must be specified with %address when using raw output type", program.toplevelModule.position)
+                    return
+                }
+                OutputType.PRG -> {
+                    when(options.launcher) {
+                        CbmPrgLauncherType.BASIC -> {
+                            program.actualLoadAddress = compTarget.machine.PROGRAM_LOAD_ADDRESS
+                        }
+                        CbmPrgLauncherType.NONE -> {
+                            errors.err("load address must be specified with %address when not using basic launcher", program.toplevelModule.position)
+                            return
+                        }
+                    }
+                }
+                OutputType.XEX -> {
+                    if(options.launcher!=CbmPrgLauncherType.NONE)
+                        throw AssemblyError("atari xex output can't contain BASIC launcher")
+                    program.actualLoadAddress = compTarget.machine.PROGRAM_LOAD_ADDRESS
+                }
+            }
+        }
+
+        // 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("P8ESTACK_LO = ${compTarget.machine.ESTACK_LO.toHex()}")
+        asmgen.out("P8ESTACK_HI = ${compTarget.machine.ESTACK_HI.toHex()}")
+
+        when(options.output) {
+            OutputType.RAW -> {
+                asmgen.out("; ---- raw assembler program ----")
+                asmgen.out("* = ${program.actualLoadAddress.toHex()}\n")
+            }
+            OutputType.PRG -> {
+                when(options.launcher) {
+                    CbmPrgLauncherType.BASIC -> {
+                        if (program.actualLoadAddress != options.compTarget.machine.PROGRAM_LOAD_ADDRESS) {
+                            errors.err("BASIC output must have load address ${options.compTarget.machine.PROGRAM_LOAD_ADDRESS.toHex()}", program.toplevelModule.position)
+                        }
+                        asmgen.out("; ---- basic program with sys call ----")
+                        asmgen.out("* = ${program.actualLoadAddress.toHex()}")
+                        val year = LocalDate.now().year
+                        asmgen.out("  .word  (+), $year")
+                        asmgen.out("  .null  $9e, format(' %d ', prog8_entrypoint), $3a, $8f, ' prog8'")
+                        asmgen.out("+\t.word  0")
+                        asmgen.out("prog8_entrypoint\t; assembly code starts here\n")
+                        if(!options.noSysInit)
+                            asmgen.out("  jsr  ${compTarget.name}.init_system")
+                        asmgen.out("  jsr  ${compTarget.name}.init_system_phase2")
+                    }
+                    CbmPrgLauncherType.NONE -> {
+                        asmgen.out("; ---- program without basic sys call ----")
+                        asmgen.out("* = ${program.actualLoadAddress.toHex()}\n")
+                        if(!options.noSysInit)
+                            asmgen.out("  jsr  ${compTarget.name}.init_system")
+                        asmgen.out("  jsr  ${compTarget.name}.init_system_phase2")
+                    }
+                }
+            }
+            OutputType.XEX -> {
+                asmgen.out("; ---- atari xex program ----")
+                asmgen.out("* = ${program.actualLoadAddress.toHex()}\n")
+                if(!options.noSysInit)
+                    asmgen.out("  jsr  ${compTarget.name}.init_system")
+                asmgen.out("  jsr  ${compTarget.name}.init_system_phase2")
+            }
+        }
+
+        if(options.zeropage !in arrayOf(ZeropageType.BASICSAFE, ZeropageType.DONTUSE)) {
+            asmgen.out("""
+                ; zeropage is clobbered so we need to reset the machine at exit
+                lda  #>sys.reset_system
+                pha
+                lda  #<sys.reset_system
+                pha""")
+        }
+
+        // make sure that on the cx16 and c64, basic rom is banked in again when we exit the program
+        when(compTarget.name) {
+            "cx16" -> {
+                if(options.floats)
+                    asmgen.out("  lda  #4 |  sta  $01")    // to use floats, make sure Basic rom is banked in
+                asmgen.out("  jsr  main.start |  lda  #4 |  sta  $01 |  rts")
+            }
+            "c64" -> asmgen.out("  jsr  main.start |  lda  #31 |  sta  $01 |  rts")
+            else -> asmgen.jmp("main.start")
+        }
+    }
+
+    private fun memorySlabs() {
+        asmgen.out("; memory slabs")
+        asmgen.out("prog8_slabs\t.block")
+        for((name, info) in allocator.memorySlabs) {
+            if(info.second>1u)
+                asmgen.out("\t.align  ${info.second.toHex()}")
+            asmgen.out("$name\t.fill  ${info.first}")
+        }
+        asmgen.out("\t.bend")
+    }
+
+    private fun footer() {
+        // the global list of all floating point constants for the whole program
+        asmgen.out("; global float constants")
+        for (flt in allocator.globalFloatConsts) {
+            val floatFill = compTarget.machine.getFloat(flt.key).makeFloatFillAsm()
+            val floatvalue = flt.key
+            asmgen.out("${flt.value}\t.byte  $floatFill  ; float $floatvalue")
+        }
+
+        // program end
+        asmgen.out("prog8_program_end\t; end of program label for progend()")
+    }
+
+    private fun block2asm(block: Block) {
+        asmgen.out("")
+        asmgen.out("; ---- block: '${block.name}' ----")
+        if(block.address!=null)
+            asmgen.out("* = ${block.address!!.toHex()}")
+        else {
+            if("align_word" in block.options())
+                asmgen.out("\t.align 2")
+            else if("align_page" in block.options())
+                asmgen.out("\t.align $100")
+        }
+
+        asmgen.out("${block.name}\t" + (if("force_output" in block.options()) ".block\n" else ".proc\n"))
+
+        asmgen.outputSourceLine(block)
+
+        zeropagevars2asm(block)
+        memdefsAndConsts2asm(block)
+        asmsubs2asm(block.statements)
+        nonZpVariables2asm(block)
+
+        asmgen.out("")
+        asmgen.out("; subroutines in this block")
+
+        // First translate regular statements, and then put the subroutines at the end.
+        // (regular statements = everything except the initialization assignments;
+        // these will be part of the prog8_init_vars init routine generated below)
+        val initializers = blockVariableInitializers.getValue(block)
+        val statements = block.statements.filterNot { it in initializers }
+        val (subroutine, stmts) = statements.partition { it is Subroutine }
+        stmts.forEach { asmgen.translate(it) }
+        subroutine.forEach { asmgen.translate(it) }
+
+        if(!options.dontReinitGlobals) {
+            // generate subroutine to initialize block-level (global) variables
+            if (initializers.isNotEmpty()) {
+                asmgen.out("prog8_init_vars\t.proc\n")
+                initializers.forEach { assign -> asmgen.translate(assign) }
+                asmgen.out("  rts\n  .pend")
+            }
+        }
+
+        asmgen.out(if("force_output" in block.options()) "\n\t.bend\n" else "\n\t.pend\n")
+    }
+
+    internal fun translateSubroutine(sub: Subroutine) {
+        var onlyVariables = false
+
+        if(sub.inline) {
+            if(options.optimize) {
+                if(sub.isAsmSubroutine || callGraph.unused(sub))
+                    return
+
+                // from an inlined subroutine only the local variables are generated,
+                // all other code statements are omitted in the subroutine itself
+                // (they've been inlined at the call site, remember?)
+                onlyVariables = true
+            }
+        }
+
+        asmgen.out("")
+
+        if(sub.isAsmSubroutine) {
+            if(sub.asmAddress!=null)
+                return  // already done at the memvars section
+
+            // asmsub with most likely just an inline asm in it
+            asmgen.out("${sub.name}\t.proc")
+            sub.statements.forEach { asmgen.translate(it) }
+            asmgen.out("  .pend\n")
+        } else {
+            // regular subroutine
+            asmgen.out("${sub.name}\t.proc")
+            zeropagevars2asm(sub)
+            memdefsAndConsts2asm(sub)
+            asmsubs2asm(sub.statements)
+
+            // the main.start subroutine is the program's entrypoint and should perform some initialization logic
+            if(sub.name=="start" && sub.definingBlock.name=="main")
+                entrypointInitialization()
+
+            if(functioncallAsmGen.optimizeIntArgsViaRegisters(sub)) {
+                asmgen.out("; simple int arg(s) passed via register(s)")
+                if(sub.parameters.size==1) {
+                    val dt = sub.parameters[0].type
+                    val target = AsmAssignTarget(TargetStorageKind.VARIABLE, program, asmgen, dt, sub, variableAsmName = sub.parameters[0].name)
+                    if(dt in ByteDatatypes)
+                        asmgen.assignRegister(RegisterOrPair.A, target)
+                    else
+                        asmgen.assignRegister(RegisterOrPair.AY, target)
+                } else {
+                    require(sub.parameters.size==2)
+                    // 2 simple byte args, first in A, second in Y
+                    val target1 = AsmAssignTarget(TargetStorageKind.VARIABLE, program, asmgen, sub.parameters[0].type, sub, variableAsmName = sub.parameters[0].name)
+                    val target2 = AsmAssignTarget(TargetStorageKind.VARIABLE, program, asmgen, sub.parameters[1].type, sub, variableAsmName = sub.parameters[1].name)
+                    asmgen.assignRegister(RegisterOrPair.A, target1)
+                    asmgen.assignRegister(RegisterOrPair.Y, target2)
+                }
+            }
+
+            if(!onlyVariables) {
+                asmgen.out("; statements")
+                sub.statements.forEach { asmgen.translate(it) }
+            }
+
+            asmgen.out("; variables")
+            val asmGenInfo = allocator.subroutineExtra(sub)
+            for((dt, name, addr) in asmGenInfo.extraVars) {
+                if(addr!=null)
+                    asmgen.out("$name = $addr")
+                else when(dt) {
+                    DataType.UBYTE -> asmgen.out("$name    .byte  0")
+                    DataType.UWORD -> asmgen.out("$name    .word  0")
+                    else -> throw AssemblyError("weird dt")
+                }
+            }
+            if(asmGenInfo.usedRegsaveA)      // will probably never occur
+                asmgen.out("prog8_regsaveA     .byte  0")
+            if(asmGenInfo.usedRegsaveX)
+                asmgen.out("prog8_regsaveX     .byte  0")
+            if(asmGenInfo.usedRegsaveY)
+                asmgen.out("prog8_regsaveY     .byte  0")
+            if(asmGenInfo.usedFloatEvalResultVar1)
+                asmgen.out("$subroutineFloatEvalResultVar1    .byte  0,0,0,0,0")
+            if(asmGenInfo.usedFloatEvalResultVar2)
+                asmgen.out("$subroutineFloatEvalResultVar2    .byte  0,0,0,0,0")
+            nonZpVariables2asm(sub)
+            asmgen.out("  .pend\n")
+        }
+    }
+
+    private fun entrypointInitialization() {
+        asmgen.out("; program startup initialization")
+        asmgen.out("  cld")
+        if(!options.dontReinitGlobals) {
+            blockVariableInitializers.forEach {
+                if (it.value.isNotEmpty())
+                    asmgen.out("  jsr  ${it.key.name}.prog8_init_vars")
+            }
+        }
+
+        // string and array variables in zeropage that have initializer value, should be initialized
+        val stringVarsWithInitInZp = allocator.zeropageVars.filter { it.value.dt==DataType.STR && it.value.initialStringValue!=null }
+        val arrayVarsWithInitInZp = allocator.zeropageVars.filter { it.value.dt in ArrayDatatypes && it.value.initialArrayValue!=null }
+        if(stringVarsWithInitInZp.isNotEmpty() || arrayVarsWithInitInZp.isNotEmpty()) {
+            asmgen.out("; zp str and array initializations")
+            stringVarsWithInitInZp.forEach {
+                val name = asmgen.asmVariableName(it.key)
+                asmgen.out("""
+                    lda  #<${name}
+                    ldy  #>${name}
+                    sta  P8ZP_SCRATCH_W1
+                    sty  P8ZP_SCRATCH_W1+1
+                    lda  #<${name}_init_value
+                    ldy  #>${name}_init_value
+                    jsr  prog8_lib.strcpy""")
+            }
+            arrayVarsWithInitInZp.forEach {
+                val size = it.value.size
+                val name = asmgen.asmVariableName(it.key)
+                asmgen.out("""
+                    lda  #<${name}_init_value
+                    ldy  #>${name}_init_value
+                    sta  cx16.r0L
+                    sty  cx16.r0H
+                    lda  #<${name}
+                    ldy  #>${name}
+                    sta  cx16.r1L
+                    sty  cx16.r1H
+                    lda  #<$size
+                    ldy  #>$size
+                    jsr  sys.memcopy""")
+            }
+            asmgen.out("  jmp  +")
+        }
+
+        stringVarsWithInitInZp.forEach {
+            val varname = asmgen.asmVariableName(it.key)+"_init_value"
+            val stringvalue = it.value.initialStringValue!!
+            outputStringvar(varname, it.value.dt, stringvalue.encoding, stringvalue.value)
+        }
+
+        arrayVarsWithInitInZp.forEach {
+            val varname = asmgen.asmVariableName(it.key)+"_init_value"
+            arrayVariable2asm(varname, it.value.dt, it.value.initialArrayValue!!, null)
+        }
+
+        asmgen.out("""+       tsx
+                    stx  prog8_lib.orig_stackpointer    ; required for sys.exit()                    
+                    ldx  #255       ; init estack ptr
+                    clv
+                    clc""")
+    }
+
+    private fun zeropagevars2asm(scope: INameScope) {
+        val zpVariables = allocator.zeropageVars.filter { it.value.originalScope==scope }
+        for ((scopedName, zpvar) in zpVariables) {
+            if (scopedName.size == 2 && scopedName[0] == "cx16" && scopedName[1][0] == 'r' && scopedName[1][1].isDigit())
+                continue        // The 16 virtual registers of the cx16 are not actual variables in zp, they're memory mapped
+            asmgen.out("${scopedName.last()} \t= ${zpvar.address} \t; zp ${zpvar.dt}")
+        }
+    }
+
+    private fun nonZpVariables2asm(block: Block) {
+        val variables = variables.blockVars[block]?.filter { !allocator.isZpVar(it.scopedname) } ?: emptyList()
+        nonZpVariables2asm(variables)
+    }
+
+    private fun nonZpVariables2asm(sub: Subroutine) {
+        val variables = variables.subroutineVars[sub]?.filter { !allocator.isZpVar(it.scopedname) } ?: emptyList()
+        nonZpVariables2asm(variables)
+    }
+
+    private fun nonZpVariables2asm(variables: List<IVariablesAndConsts.StaticVariable>) {
+        asmgen.out("")
+        asmgen.out("; non-zeropage variables")
+        val (stringvars, othervars) = variables.partition { it.type==DataType.STR }
+        stringvars.forEach {
+            val stringvalue = it.initialValue as StringLiteral
+            outputStringvar(it.scopedname.last(), it.type, stringvalue.encoding, stringvalue.value)
+        }
+        othervars.sortedBy { it.type }.forEach {
+            staticVariable2asm(it)
+        }
+    }
+
+    private fun staticVariable2asm(variable: IVariablesAndConsts.StaticVariable) {
+        val name = variable.scopedname.last()
+        val value = variable.initialValue
+        val staticValue: Number =
+            if(value!=null) {
+                if(value is NumericLiteral) {
+                    if(value.type== DataType.FLOAT)
+                        value.number
+                    else
+                        value.number.toInt()
+                } else {
+                    if(variable.type in NumericDatatypes)
+                        throw AssemblyError("can only deal with constant numeric values for global vars")
+                    else 0
+                }
+            } else 0
+
+        when (variable.type) {
+            DataType.UBYTE -> asmgen.out("$name\t.byte  ${staticValue.toHex()}")
+            DataType.BYTE -> asmgen.out("$name\t.char  $staticValue")
+            DataType.UWORD -> asmgen.out("$name\t.word  ${staticValue.toHex()}")
+            DataType.WORD -> asmgen.out("$name\t.sint  $staticValue")
+            DataType.FLOAT -> {
+                if(staticValue==0) {
+                    asmgen.out("$name\t.byte  0,0,0,0,0  ; float")
+                } else {
+                    val floatFill = compTarget.machine.getFloat(staticValue).makeFloatFillAsm()
+                    asmgen.out("$name\t.byte  $floatFill  ; float $staticValue")
+                }
+            }
+            DataType.STR -> {
+                throw AssemblyError("all string vars should have been interned into prog")
+            }
+            in ArrayDatatypes -> arrayVariable2asm(name, variable.type, value as? ArrayLiteral, variable.arraysize)
+            else -> {
+                throw AssemblyError("weird dt")
+            }
+        }
+    }
+
+    private fun arrayVariable2asm(varname: String, dt: DataType, value: ArrayLiteral?, orNumberOfZeros: Int?) {
+        when(dt) {
+            DataType.ARRAY_UB -> {
+                val data = makeArrayFillDataUnsigned(dt, value, orNumberOfZeros)
+                if (data.size <= 16)
+                    asmgen.out("$varname\t.byte  ${data.joinToString()}")
+                else {
+                    asmgen.out(varname)
+                    for (chunk in data.chunked(16))
+                        asmgen.out("  .byte  " + chunk.joinToString())
+                }
+            }
+            DataType.ARRAY_B -> {
+                val data = makeArrayFillDataSigned(dt, value, orNumberOfZeros)
+                if (data.size <= 16)
+                    asmgen.out("$varname\t.char  ${data.joinToString()}")
+                else {
+                    asmgen.out(varname)
+                    for (chunk in data.chunked(16))
+                        asmgen.out("  .char  " + chunk.joinToString())
+                }
+            }
+            DataType.ARRAY_UW -> {
+                val data = makeArrayFillDataUnsigned(dt, value, orNumberOfZeros)
+                if (data.size <= 16)
+                    asmgen.out("$varname\t.word  ${data.joinToString()}")
+                else {
+                    asmgen.out(varname)
+                    for (chunk in data.chunked(16))
+                        asmgen.out("  .word  " + chunk.joinToString())
+                }
+            }
+            DataType.ARRAY_W -> {
+                val data = makeArrayFillDataSigned(dt, value, orNumberOfZeros)
+                if (data.size <= 16)
+                    asmgen.out("$varname\t.sint  ${data.joinToString()}")
+                else {
+                    asmgen.out(varname)
+                    for (chunk in data.chunked(16))
+                        asmgen.out("  .sint  " + chunk.joinToString())
+                }
+            }
+            DataType.ARRAY_F -> {
+                val array = value?.value ?:
+                                Array(orNumberOfZeros!!) { defaultZero(ArrayToElementTypes.getValue(dt), Position.DUMMY) }
+                val floatFills = array.map {
+                    val number = (it as NumericLiteral).number
+                    compTarget.machine.getFloat(number).makeFloatFillAsm()
+                }
+                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 memdefsAndConsts2asm(block: Block) {
+        val mvs = variables.blockMemvars[block] ?: emptySet()
+        val consts = variables.blockConsts[block] ?: emptySet()
+        memdefsAndConsts2asm(mvs, consts)
+    }
+
+    private fun memdefsAndConsts2asm(sub: Subroutine) {
+        val mvs = variables.subroutineMemvars[sub] ?: emptySet()
+        val consts = variables.subroutineConsts[sub] ?: emptySet()
+        memdefsAndConsts2asm(mvs, consts)
+    }
+
+    private fun memdefsAndConsts2asm(
+        memvars: Set<IVariablesAndConsts.MemoryMappedVariable>,
+        consts: Set<IVariablesAndConsts.ConstantNumberSymbol>
+    ) {
+        memvars.forEach {
+            asmgen.out("  ${it.scopedname.last()} = ${it.address.toHex()}")
+        }
+        consts.forEach {
+            if(it.type==DataType.FLOAT)
+                asmgen.out("  ${it.scopedname.last()} = ${it.value}")
+            else
+                asmgen.out("  ${it.scopedname.last()} = ${it.value.toHex()}")
+        }
+    }
+
+    private fun asmsubs2asm(statements: List<Statement>) {
+        statements
+            .filter { it is Subroutine && it.isAsmSubroutine && it.asmAddress!=null }
+            .forEach { asmsub ->
+                asmsub as Subroutine
+                asmgen.out("  ${asmsub.name} = ${asmsub.asmAddress!!.toHex()}")
+            }
+    }
+
+    private fun outputStringvar(varname: String, dt: DataType, encoding: Encoding, value: String) {
+        asmgen.out("$varname\t; $dt $encoding:\"${escape(value).replace("\u0000", "<NULL>")}\"")
+        val bytes = compTarget.encodeString(value, encoding).plus(0.toUByte())
+        val outputBytes = bytes.map { "$" + it.toString(16).padStart(2, '0') }
+        for (chunk in outputBytes.chunked(16))
+            asmgen.out("  .byte  " + chunk.joinToString())
+    }
+
+    private fun makeArrayFillDataUnsigned(dt: DataType, value: ArrayLiteral?, orNumberOfZeros: Int?): List<String> {
+        val array = value?.value ?:
+                        Array(orNumberOfZeros!!) { defaultZero(ArrayToElementTypes.getValue(dt), Position.DUMMY) }
+        return when (dt) {
+            DataType.ARRAY_UB ->
+                // byte array can never contain pointer-to types, so treat values as all integers
+                array.map {
+                    val number = (it as NumericLiteral).number.toInt()
+                    "$"+number.toString(16).padStart(2, '0')
+                }
+            DataType.ARRAY_UW -> array.map {
+                when (it) {
+                    is NumericLiteral -> {
+                        "$" + it.number.toInt().toString(16).padStart(4, '0')
+                    }
+                    is AddressOf -> {
+                        asmgen.asmSymbolName(it.identifier)
+                    }
+                    is IdentifierReference -> {
+                        asmgen.asmSymbolName(it)
+                    }
+                    else -> throw AssemblyError("weird array elt dt")
+                }
+            }
+            else -> throw AssemblyError("invalid dt")
+        }
+    }
+
+    private fun makeArrayFillDataSigned(dt: DataType, value: ArrayLiteral?, orNumberOfZeros: Int?): List<String> {
+        val array = value?.value ?:
+                        Array(orNumberOfZeros!!) { defaultZero(ArrayToElementTypes.getValue(dt), Position.DUMMY) }
+        return when (dt) {
+            DataType.ARRAY_UB ->
+                // byte array can never contain pointer-to types, so treat values as all integers
+                array.map {
+                    val number = (it as NumericLiteral).number.toInt()
+                    "$"+number.toString(16).padStart(2, '0')
+                }
+            DataType.ARRAY_B ->
+                // byte array can never contain pointer-to types, so treat values as all integers
+                array.map {
+                    val number = (it as NumericLiteral).number.toInt()
+                    val hexnum = number.absoluteValue.toString(16).padStart(2, '0')
+                    if(number>=0)
+                        "$$hexnum"
+                    else
+                        "-$$hexnum"
+                }
+            DataType.ARRAY_UW -> array.map {
+                val number = (it as NumericLiteral).number.toInt()
+                "$" + number.toString(16).padStart(4, '0')
+            }
+            DataType.ARRAY_W -> array.map {
+                val number = (it as NumericLiteral).number.toInt()
+                val hexnum = number.absoluteValue.toString(16).padStart(4, '0')
+                if(number>=0)
+                    "$$hexnum"
+                else
+                    "-$$hexnum"
+            }
+            else -> throw AssemblyError("invalid dt")
+        }
+    }
+
+}

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

@@ -0,0 +1,166 @@
+package prog8.codegen.cpu6502
+
+import com.github.michaelbull.result.fold
+import com.github.michaelbull.result.onSuccess
+import prog8.ast.base.ArrayDatatypes
+import prog8.ast.base.DataType
+import prog8.ast.base.IntegerDatatypes
+import prog8.ast.expressions.StringLiteral
+import prog8.ast.statements.Subroutine
+import prog8.ast.statements.ZeropageWish
+import prog8.compilerinterface.*
+
+
+internal class VariableAllocator(private val vars: IVariablesAndConsts,
+                                 private val options: CompilationOptions,
+                                 private val errors: IErrorReporter) {
+
+    private val zeropage = options.compTarget.machine.zeropage
+    private val subroutineExtras = mutableMapOf<Subroutine, SubroutineExtraAsmInfo>()
+    private val memorySlabsInternal = mutableMapOf<String, Pair<UInt, UInt>>()
+    internal val memorySlabs: Map<String, Pair<UInt, UInt>> = memorySlabsInternal
+    internal val globalFloatConsts = mutableMapOf<Double, String>()     // all float values in the entire program (value -> varname)
+    internal val zeropageVars: Map<List<String>, Zeropage.ZpAllocation> = zeropage.allocatedVariables
+
+    internal fun getMemorySlab(name: String) = memorySlabsInternal[name]
+    internal fun allocateMemorySlab(name: String, size: UInt, align: UInt) {
+        memorySlabsInternal[name] = Pair(size, align)
+    }
+
+    /**
+     * Allocate variables into the Zeropage.
+     * The result should be retrieved from the current machine's zeropage object!
+     */
+    internal fun allocateZeropageVariables() {
+        if(options.zeropage== ZeropageType.DONTUSE)
+            return
+
+        val allVariables = (
+                        vars.blockVars.asSequence().flatMap { it.value } +
+                        vars.subroutineVars.asSequence().flatMap { it.value }
+                ).toList()
+
+        val numberOfAllocatableVariables = allVariables.size
+        val varsRequiringZp = allVariables.filter { it.zp == ZeropageWish.REQUIRE_ZEROPAGE }
+        val varsPreferringZp = allVariables.filter { it.zp == ZeropageWish.PREFER_ZEROPAGE }
+        val varsDontCare = allVariables.filter { it.zp == ZeropageWish.DONTCARE }
+        val numberOfExplicitNonZpVariables = allVariables.count { it.zp == ZeropageWish.NOT_IN_ZEROPAGE }
+        require(varsDontCare.size + varsRequiringZp.size + varsPreferringZp.size + numberOfExplicitNonZpVariables == numberOfAllocatableVariables)
+
+        var numVariablesAllocatedInZP = 0
+        var numberOfNonIntegerVariables = 0
+
+        varsRequiringZp.forEach { variable ->
+            val numElements = numArrayElements(variable)
+            val result = zeropage.allocate(
+                variable.scopedname,
+                variable.type,
+                variable.scope,
+                numElements,
+                variable.initialValue,
+                variable.position,
+                errors
+            )
+            result.fold(
+                success = {
+                    numVariablesAllocatedInZP++
+                },
+                failure = {
+                    errors.err(it.message!!, variable.position)
+                }
+            )
+        }
+
+        if(errors.noErrors()) {
+            varsPreferringZp.forEach { variable ->
+                val numElements = numArrayElements(variable)
+                val result = zeropage.allocate(
+                    variable.scopedname,
+                    variable.type,
+                    variable.scope,
+                    numElements,
+                    variable.initialValue,
+                    variable.position,
+                    errors
+                )
+                result.onSuccess { numVariablesAllocatedInZP++ }
+                //  no need to check for allocation error, if there is one, just allocate in normal system ram.
+            }
+
+            // try to allocate any other interger variables into the zeropage until it is full.
+            // TODO some form of intelligent priorization? most often used variables first? loopcounter vars first? ...?
+            if(errors.noErrors()) {
+                for (variable in varsDontCare) {
+                    if(variable.type in IntegerDatatypes) {
+                        if(zeropage.free.isEmpty()) {
+                            break
+                        } else {
+                            val numElements = numArrayElements(variable)
+                            val result = zeropage.allocate(
+                                variable.scopedname,
+                                variable.type,
+                                variable.scope,
+                                numElements,
+                                variable.initialValue,
+                                variable.position,
+                                errors
+                            )
+                            result.onSuccess { numVariablesAllocatedInZP++ }
+                        }
+                    } else
+                        numberOfNonIntegerVariables++
+                }
+            }
+        }
+
+        println("  number of allocated vars: $numberOfAllocatableVariables")
+        println("  put into zeropage: $numVariablesAllocatedInZP,  non-zp allocatable: ${numberOfNonIntegerVariables+numberOfExplicitNonZpVariables}")
+        println("  zeropage free space: ${zeropage.free.size} bytes")
+    }
+
+    internal fun isZpVar(scopedName: List<String>) = scopedName in zeropage.allocatedVariables
+
+    private fun numArrayElements(variable: IVariablesAndConsts.StaticVariable) =
+        when(variable.type) {
+            DataType.STR -> (variable.initialValue as StringLiteral).value.length
+            in ArrayDatatypes -> variable.arraysize!!
+            else -> null
+        }
+
+    internal fun subroutineExtra(sub: Subroutine): SubroutineExtraAsmInfo {
+        var extra = subroutineExtras[sub]
+        return if(extra==null) {
+            extra = SubroutineExtraAsmInfo()
+            subroutineExtras[sub] = extra
+            extra
+        }
+        else
+            extra
+    }
+
+    internal fun getFloatAsmConst(number: Double): String {
+        val asmName = globalFloatConsts[number]
+        if(asmName!=null)
+            return asmName
+
+        val newName = "prog8_float_const_${globalFloatConsts.size}"
+        globalFloatConsts[number] = newName
+        return newName
+    }
+}
+
+/**
+ * This class contains various attributes that influence the assembly code generator.
+ * Conceptually it should be part of any INameScope.
+ * But because the resulting code only creates "real" scopes on a subroutine level,
+ * it's more consistent to only define these attributes on a Subroutine node.
+ */
+internal class SubroutineExtraAsmInfo {
+    var usedRegsaveA = false
+    var usedRegsaveX = false
+    var usedRegsaveY = false
+    var usedFloatEvalResultVar1 = false
+    var usedFloatEvalResultVar2 = false
+
+    val extraVars = mutableListOf<Triple<DataType, String, UInt?>>()
+}

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

@@ -0,0 +1,221 @@
+package prog8.codegen.cpu6502.assignment
+
+import prog8.ast.Program
+import prog8.ast.base.*
+import prog8.ast.expressions.*
+import prog8.ast.statements.*
+import prog8.codegen.cpu6502.AsmGen
+import prog8.compilerinterface.AssemblyError
+import prog8.compilerinterface.IMemSizer
+
+
+internal enum class TargetStorageKind {
+    VARIABLE,
+    ARRAY,
+    MEMORY,
+    REGISTER,
+    STACK
+}
+
+internal enum class SourceStorageKind {
+    LITERALNUMBER,
+    VARIABLE,
+    ARRAY,
+    MEMORY,
+    REGISTER,
+    STACK,              // value is already present on stack
+    EXPRESSION,         // expression in ast-form, still to be evaluated
+}
+
+internal class AsmAssignTarget(val kind: TargetStorageKind,
+                               private val program: Program,
+                               private val asmgen: AsmGen,
+                               val datatype: DataType,
+                               val scope: Subroutine?,
+                               private val variableAsmName: String? = null,
+                               val array: ArrayIndexedExpression? = null,
+                               val memory: DirectMemoryWrite? = null,
+                               val register: RegisterOrPair? = null,
+                               val origAstTarget: AssignTarget? = null
+                               )
+{
+    val constMemoryAddress by lazy { memory?.addressExpression?.constValue(program)?.number?.toUInt() ?: 0u}
+    val constArrayIndexValue by lazy { array?.indexer?.constIndex()?.toUInt() }
+    val asmVarname: String by lazy {
+        if (array == null)
+            variableAsmName!!
+        else
+            asmgen.asmVariableName(array.arrayvar)
+    }
+
+    lateinit var origAssign: AsmAssignment
+
+    init {
+        if(register!=null && datatype !in NumericDatatypes)
+            throw AssemblyError("register must be integer or float type")
+    }
+
+    companion object {
+        fun fromAstAssignment(assign: Assignment, program: Program, asmgen: AsmGen): AsmAssignTarget {
+            with(assign.target) {
+                val idt = inferType(program)
+                val dt = idt.getOrElse { throw AssemblyError("unknown dt") }
+                when {
+                    identifier != null -> {
+                        val parameter = identifier!!.targetVarDecl(program)?.subroutineParameter
+                        if (parameter!=null) {
+                            val sub = parameter.definingSubroutine!!
+                            if (sub.isAsmSubroutine) {
+                                val reg = sub.asmParameterRegisters[sub.parameters.indexOf(parameter)]
+                                if(reg.statusflag!=null)
+                                    throw AssemblyError("can't assign value to processor statusflag directly")
+                                else
+                                    return AsmAssignTarget(TargetStorageKind.REGISTER, program, asmgen, dt, assign.definingSubroutine, register=reg.registerOrPair, origAstTarget = this)
+                            }
+                        }
+                        return AsmAssignTarget(TargetStorageKind.VARIABLE, program, asmgen, dt, assign.definingSubroutine, variableAsmName = asmgen.asmVariableName(identifier!!), origAstTarget =  this)
+                    }
+                    arrayindexed != null -> return AsmAssignTarget(TargetStorageKind.ARRAY, program, asmgen, dt, assign.definingSubroutine, array = arrayindexed, origAstTarget =  this)
+                    memoryAddress != null -> return AsmAssignTarget(TargetStorageKind.MEMORY, program, asmgen, dt, assign.definingSubroutine, memory =  memoryAddress, origAstTarget =  this)
+                    else -> throw AssemblyError("weird target")
+                }
+            }
+        }
+
+        fun fromRegisters(registers: RegisterOrPair, signed: Boolean, scope: Subroutine?, program: Program, asmgen: AsmGen): AsmAssignTarget =
+                when(registers) {
+                    RegisterOrPair.A,
+                    RegisterOrPair.X,
+                    RegisterOrPair.Y -> AsmAssignTarget(TargetStorageKind.REGISTER, program, asmgen, if(signed) DataType.BYTE else DataType.UBYTE, scope, register = registers)
+                    RegisterOrPair.AX,
+                    RegisterOrPair.AY,
+                    RegisterOrPair.XY -> AsmAssignTarget(TargetStorageKind.REGISTER, program, asmgen, if(signed) DataType.WORD else DataType.UWORD, scope, register = registers)
+                    RegisterOrPair.FAC1,
+                    RegisterOrPair.FAC2 -> AsmAssignTarget(TargetStorageKind.REGISTER, program, asmgen, DataType.FLOAT, scope, register = registers)
+                    RegisterOrPair.R0,
+                    RegisterOrPair.R1,
+                    RegisterOrPair.R2,
+                    RegisterOrPair.R3,
+                    RegisterOrPair.R4,
+                    RegisterOrPair.R5,
+                    RegisterOrPair.R6,
+                    RegisterOrPair.R7,
+                    RegisterOrPair.R8,
+                    RegisterOrPair.R9,
+                    RegisterOrPair.R10,
+                    RegisterOrPair.R11,
+                    RegisterOrPair.R12,
+                    RegisterOrPair.R13,
+                    RegisterOrPair.R14,
+                    RegisterOrPair.R15 -> AsmAssignTarget(TargetStorageKind.REGISTER, program, asmgen, if(signed) DataType.WORD else DataType.UWORD, scope, register = registers)
+                }
+    }
+}
+
+internal class AsmAssignSource(val kind: SourceStorageKind,
+                               private val program: Program,
+                               private val asmgen: AsmGen,
+                               val datatype: DataType,
+                               private val variableAsmName: String? = null,
+                               val array: ArrayIndexedExpression? = null,
+                               val memory: DirectMemoryRead? = null,
+                               val register: RegisterOrPair? = null,
+                               val number: NumericLiteral? = null,
+                               val expression: Expression? = null
+)
+{
+    val constMemoryAddress by lazy { memory?.addressExpression?.constValue(program)?.number?.toUInt() ?: 0u}
+    val constArrayIndexValue by lazy { array?.indexer?.constIndex()?.toUInt() }
+
+    val asmVarname: String
+        get() = if(array==null)
+            variableAsmName!!
+        else
+            asmgen.asmVariableName(array.arrayvar)
+
+    companion object {
+        fun fromAstSource(indexer: ArrayIndex, program: Program, asmgen: AsmGen): AsmAssignSource = fromAstSource(indexer.indexExpr, program, asmgen)
+
+        fun fromAstSource(value: Expression, program: Program, asmgen: AsmGen): AsmAssignSource {
+            val cv = value.constValue(program)
+            if(cv!=null)
+                return AsmAssignSource(SourceStorageKind.LITERALNUMBER, program, asmgen, cv.type, number = cv)
+
+            return when(value) {
+                is NumericLiteral -> throw AssemblyError("should have been constant value")
+                is StringLiteral -> throw AssemblyError("string literal value should not occur anymore for asm generation")
+                is ArrayLiteral -> throw AssemblyError("array literal value should not occur anymore for asm generation")
+                is IdentifierReference -> {
+                    val parameter = value.targetVarDecl(program)?.subroutineParameter
+                    if(parameter!=null && parameter.definingSubroutine!!.isAsmSubroutine)
+                        throw AssemblyError("can't assign from a asmsub register parameter $value ${value.position}")
+                    val dt = value.inferType(program).getOr(DataType.UNDEFINED)
+                    val varName=asmgen.asmVariableName(value)
+                    // special case: "cx16.r[0-15]" are 16-bits virtual registers of the commander X16 system
+                    if(dt == DataType.UWORD && varName.lowercase().startsWith("cx16.r")) {
+                        val regStr = varName.lowercase().substring(5)
+                        val reg = RegisterOrPair.valueOf(regStr.uppercase())
+                        AsmAssignSource(SourceStorageKind.REGISTER, program, asmgen, dt, register = reg)
+                    } else {
+                        AsmAssignSource(SourceStorageKind.VARIABLE, program, asmgen, dt, variableAsmName = varName)
+                    }
+                }
+                is DirectMemoryRead -> {
+                    AsmAssignSource(SourceStorageKind.MEMORY, program, asmgen, DataType.UBYTE, memory = value)
+                }
+                is ArrayIndexedExpression -> {
+                    val dt = value.inferType(program).getOrElse { throw AssemblyError("unknown dt") }
+                    AsmAssignSource(SourceStorageKind.ARRAY, program, asmgen, dt, array = value)
+                }
+                is BuiltinFunctionCall -> {
+                    val returnType = value.inferType(program)
+                    AsmAssignSource(SourceStorageKind.EXPRESSION, program, asmgen, returnType.getOrElse { throw AssemblyError("unknown dt") }, expression = value)
+                }
+                is FunctionCallExpression -> {
+                    val sub = value.target.targetSubroutine(program)!!
+                    val returnType = sub.returntypes.zip(sub.asmReturnvaluesRegisters).firstOrNull { rr -> rr.second.registerOrPair != null || rr.second.statusflag!=null }?.first
+                            ?: throw AssemblyError("can't translate zero return values in assignment")
+
+                    AsmAssignSource(SourceStorageKind.EXPRESSION, program, asmgen, returnType, expression = value)
+                }
+                else -> {
+                    val returnType = value.inferType(program)
+                    AsmAssignSource(SourceStorageKind.EXPRESSION, program, asmgen, returnType.getOrElse { throw AssemblyError("unknown dt") }, expression = value)
+                }
+            }
+        }
+    }
+
+    fun adjustSignedUnsigned(target: AsmAssignTarget): AsmAssignSource {
+        // allow some signed/unsigned relaxations
+
+        fun withAdjustedDt(newType: DataType) =
+                AsmAssignSource(kind, program, asmgen, newType, variableAsmName, array, memory, register, number, expression)
+
+        if(target.datatype!=datatype) {
+            if(target.datatype in ByteDatatypes && datatype in ByteDatatypes) {
+                return withAdjustedDt(target.datatype)
+            } else if(target.datatype in WordDatatypes && datatype in WordDatatypes) {
+                return withAdjustedDt(target.datatype)
+            }
+        }
+        return this
+    }
+
+}
+
+
+internal class AsmAssignment(val source: AsmAssignSource,
+                             val target: AsmAssignTarget,
+                             val isAugmentable: Boolean,
+                             memsizer: IMemSizer,
+                             val position: Position) {
+
+    init {
+        if(target.register !in arrayOf(RegisterOrPair.XY, RegisterOrPair.AX, RegisterOrPair.AY))
+            require(source.datatype != DataType.UNDEFINED) { "must not be placeholder/undefined datatype" }
+            require(memsizer.memorySize(source.datatype) <= memsizer.memorySize(target.datatype)) {
+                "source dt size must be less or equal to target dt size at $position"
+            }
+    }
+}

codeGenExperimental6502/build.gradle

@@ -0,0 +1,46 @@
+
+plugins {
+    id 'java'
+    id 'application'
+    id "org.jetbrains.kotlin.jvm"
+}
+
+java {
+    toolchain {
+        languageVersion = JavaLanguageVersion.of(javaVersion)
+    }
+}
+
+compileKotlin {
+    kotlinOptions {
+        jvmTarget = javaVersion
+    }
+}
+
+compileTestKotlin {
+    kotlinOptions {
+        jvmTarget = javaVersion
+    }
+}
+
+dependencies {
+    implementation project(':compilerInterfaces')
+    implementation project(':compilerAst')
+    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8"
+    // implementation "org.jetbrains.kotlin:kotlin-reflect"
+    implementation "com.michael-bull.kotlin-result:kotlin-result-jvm:1.1.12"
+
+}
+
+sourceSets {
+    main {
+        java {
+            srcDirs = ["${project.projectDir}/src"]
+        }
+        resources {
+            srcDirs = ["${project.projectDir}/res"]
+        }
+    }
+}
+
+// note: there are no unit tests in this module!

codeGenExperimental6502/codeGenExperimental6502.iml

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

codeGenExperimental6502/src/prog8/codegen/experimental6502/AsmGen.kt

@@ -0,0 +1,18 @@
+package prog8.codegen.experimental6502
+
+import prog8.ast.Program
+import prog8.compilerinterface.*
+
+class AsmGen(internal val program: Program,
+             internal val errors: IErrorReporter,
+             internal val variables: IVariablesAndConsts,
+             internal val options: CompilationOptions): IAssemblyGenerator {
+
+    override fun compileToAssembly(): IAssemblyProgram? {
+
+        println("\n** experimental 65(c)02 code generator **\n")
+
+        println("..todo: create assembly code into ${options.outputDir.toAbsolutePath()}..")
+        return AssemblyProgram("dummy")
+    }
+}

codeGenExperimental6502/src/prog8/codegen/experimental6502/AssemblyProgram.kt

@@ -0,0 +1,13 @@
+package prog8.codegen.experimental6502
+
+import prog8.compilerinterface.CompilationOptions
+import prog8.compilerinterface.IAssemblyProgram
+
+
+internal class AssemblyProgram(override val name: String) : IAssemblyProgram
+{
+    override fun assemble(options: CompilationOptions): Boolean {
+        println("..todo: assemble code into binary..")
+        return false
+    }
+}

codeGenTargets/build.gradle

@@ -0,0 +1,46 @@
+
+plugins {
+    id 'java'
+    id 'application'
+    id "org.jetbrains.kotlin.jvm"
+}
+
+java {
+    toolchain {
+        languageVersion = JavaLanguageVersion.of(javaVersion)
+    }
+}
+
+compileKotlin {
+    kotlinOptions {
+        jvmTarget = javaVersion
+    }
+}
+
+compileTestKotlin {
+    kotlinOptions {
+        jvmTarget = javaVersion
+    }
+}
+
+dependencies {
+    implementation project(':compilerInterfaces')
+    implementation project(':compilerAst')
+    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8"
+    // implementation "org.jetbrains.kotlin:kotlin-reflect"
+    implementation "com.michael-bull.kotlin-result:kotlin-result-jvm:1.1.12"
+
+}
+
+sourceSets {
+    main {
+        java {
+            srcDirs = ["${project.projectDir}/src"]
+        }
+        resources {
+            srcDirs = ["${project.projectDir}/res"]
+        }
+    }
+}
+
+// note: there are no unit tests in this module!

codeGenTargets/codeGenTargets.iml

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

codeGenTargets/readme-tests.txt

@@ -0,0 +1,2 @@
+Unittests for things in this module are located in the Compiler module instead,
+for convenience sake, and to not spread the test cases around too much.

codeGenTargets/src/prog8/codegen/target/AtariTarget.kt

@@ -0,0 +1,52 @@
+package prog8.codegen.target
+
+import prog8.ast.base.*
+import prog8.ast.expressions.Expression
+import prog8.ast.expressions.StringLiteral
+import prog8.ast.statements.RegisterOrStatusflag
+import prog8.ast.statements.Subroutine
+import prog8.ast.statements.VarDecl
+import prog8.codegen.target.atari.AtariMachineDefinition
+import prog8.codegen.target.cbm.asmsub6502ArgsEvalOrder
+import prog8.codegen.target.cbm.asmsub6502ArgsHaveRegisterClobberRisk
+import prog8.compilerinterface.*
+
+
+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 asmsubArgsEvalOrder(sub: Subroutine): List<Int> =
+        asmsub6502ArgsEvalOrder(sub)
+    override fun asmsubArgsHaveRegisterClobberRisk(args: List<Expression>, paramRegisters: List<RegisterOrStatusflag>) =
+        asmsub6502ArgsHaveRegisterClobberRisk(args, paramRegisters)
+
+    override fun memorySize(dt: DataType): Int {
+        return when(dt) {
+            in ByteDatatypes -> 1
+            in WordDatatypes, in PassByReferenceDatatypes -> 2
+            DataType.FLOAT -> 6
+            else -> Int.MIN_VALUE
+        }
+    }
+
+    override fun memorySize(decl: VarDecl): Int {
+        return when(decl.type) {
+            VarDeclType.CONST -> 0
+            VarDeclType.VAR, VarDeclType.MEMORY -> {
+                when(val dt = decl.datatype) {
+                    in NumericDatatypes -> return memorySize(dt)
+                    in ArrayDatatypes -> decl.arraysize!!.constIndex()!! * memorySize(ArrayToElementTypes.getValue(dt))
+                    DataType.STR -> (decl.value as StringLiteral).value.length + 1
+                    else -> 0
+                }
+            }
+        }
+    }
+}

codeGenTargets/src/prog8/codegen/target/C128Target.kt

@@ -0,0 +1,27 @@
+package prog8.codegen.target
+
+import prog8.ast.expressions.Expression
+import prog8.ast.statements.RegisterOrStatusflag
+import prog8.ast.statements.Subroutine
+import prog8.codegen.target.c128.C128MachineDefinition
+import prog8.codegen.target.cbm.CbmMemorySizer
+import prog8.codegen.target.cbm.asmsub6502ArgsEvalOrder
+import prog8.codegen.target.cbm.asmsub6502ArgsHaveRegisterClobberRisk
+import prog8.compilerinterface.*
+
+
+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"
+    }
+
+    override fun asmsubArgsEvalOrder(sub: Subroutine): List<Int> =
+        asmsub6502ArgsEvalOrder(sub)
+    override fun asmsubArgsHaveRegisterClobberRisk(args: List<Expression>, paramRegisters: List<RegisterOrStatusflag>) =
+        asmsub6502ArgsHaveRegisterClobberRisk(args, paramRegisters)
+}

codeGenTargets/src/prog8/codegen/target/C64Target.kt

@@ -0,0 +1,27 @@
+package prog8.codegen.target
+
+import prog8.ast.expressions.Expression
+import prog8.ast.statements.RegisterOrStatusflag
+import prog8.ast.statements.Subroutine
+import prog8.codegen.target.c64.C64MachineDefinition
+import prog8.codegen.target.cbm.CbmMemorySizer
+import prog8.codegen.target.cbm.asmsub6502ArgsEvalOrder
+import prog8.codegen.target.cbm.asmsub6502ArgsHaveRegisterClobberRisk
+import prog8.compilerinterface.*
+
+
+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"
+    }
+
+    override fun asmsubArgsEvalOrder(sub: Subroutine): List<Int> =
+        asmsub6502ArgsEvalOrder(sub)
+    override fun asmsubArgsHaveRegisterClobberRisk(args: List<Expression>, paramRegisters: List<RegisterOrStatusflag>) =
+        asmsub6502ArgsHaveRegisterClobberRisk(args, paramRegisters)
+}

codeGenTargets/src/prog8/codegen/target/Cx16Target.kt

@@ -0,0 +1,27 @@
+package prog8.codegen.target
+
+import prog8.ast.expressions.Expression
+import prog8.ast.statements.RegisterOrStatusflag
+import prog8.ast.statements.Subroutine
+import prog8.codegen.target.cbm.CbmMemorySizer
+import prog8.codegen.target.cbm.asmsub6502ArgsEvalOrder
+import prog8.codegen.target.cbm.asmsub6502ArgsHaveRegisterClobberRisk
+import prog8.codegen.target.cx16.CX16MachineDefinition
+import prog8.compilerinterface.*
+
+
+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"
+    }
+
+    override fun asmsubArgsEvalOrder(sub: Subroutine): List<Int> =
+        asmsub6502ArgsEvalOrder(sub)
+    override fun asmsubArgsHaveRegisterClobberRisk(args: List<Expression>, paramRegisters: List<RegisterOrStatusflag>) =
+        asmsub6502ArgsHaveRegisterClobberRisk(args, paramRegisters)
+}

codeGenTargets/src/prog8/codegen/target/Encoder.kt

@@ -0,0 +1,38 @@
+package prog8.codegen.target
+
+import com.github.michaelbull.result.fold
+import prog8.codegen.target.cbm.AtasciiEncoding
+import prog8.codegen.target.cbm.IsoEncoding
+import prog8.codegen.target.cbm.PetsciiEncoding
+import prog8.compilerinterface.Encoding
+import prog8.compilerinterface.IStringEncoding
+import prog8.compilerinterface.InternalCompilerException
+
+internal object Encoder: IStringEncoding {
+    override fun encodeString(str: String, encoding: Encoding): List<UByte> {
+        val coded = when(encoding) {
+            Encoding.PETSCII -> PetsciiEncoding.encodePetscii(str, true)
+            Encoding.SCREENCODES -> PetsciiEncoding.encodeScreencode(str, true)
+            Encoding.ISO -> IsoEncoding.encode(str)
+            Encoding.ATASCII -> AtasciiEncoding.encode(str)
+            else -> throw InternalCompilerException("unsupported encoding $encoding")
+        }
+        return coded.fold(
+            failure = { throw it },
+            success = { it }
+        )
+    }
+    override fun decodeString(bytes: List<UByte>, encoding: Encoding): String {
+        val decoded = when(encoding) {
+            Encoding.PETSCII -> PetsciiEncoding.decodePetscii(bytes, true)
+            Encoding.SCREENCODES -> PetsciiEncoding.decodeScreencode(bytes, true)
+            Encoding.ISO -> IsoEncoding.decode(bytes)
+            Encoding.ATASCII -> AtasciiEncoding.decode(bytes)
+            else -> throw InternalCompilerException("unsupported encoding $encoding")
+        }
+        return decoded.fold(
+            failure = { throw it },
+            success = { it }
+        )
+    }
+}

codeGenTargets/src/prog8/codegen/target/atari/AtariMachineDefinition.kt

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

codeGenTargets/src/prog8/codegen/target/atari/AtariZeropage.kt

@@ -0,0 +1,45 @@
+package prog8.codegen.target.atari
+
+import prog8.compilerinterface.CompilationOptions
+import prog8.compilerinterface.InternalCompilerException
+import prog8.compilerinterface.Zeropage
+import prog8.compilerinterface.ZeropageType
+
+class AtariZeropage(options: CompilationOptions) : Zeropage(options) {
+
+    override val SCRATCH_B1 = 0xcbu      // temp storage for a single byte
+    override val SCRATCH_REG = 0xccu     // temp storage for a register, must be B1+1
+    override val SCRATCH_W1 = 0xcdu      // temp storage 1 for a word  $cd+$ce
+    override val SCRATCH_W2 = 0xcfu      // temp storage 2 for a word  $cf+$d0        TODO is $d0 okay to use?
+
+
+    init {
+        if (options.floats && options.zeropage !in arrayOf(
+                ZeropageType.FLOATSAFE,
+                ZeropageType.BASICSAFE,
+                ZeropageType.DONTUSE
+            ))
+            throw InternalCompilerException("when floats are enabled, zero page type should be 'floatsafe' or 'basicsafe' or 'dontuse'")
+
+        when (options.zeropage) {
+            ZeropageType.FULL -> {
+                // TODO all atari usable zero page locations, except the ones used by the system's IRQ routine
+                free.addAll(0x00u..0xffu)
+                // TODO atari  free.removeAll(setOf(0xa0u, 0xa1u, 0xa2u, 0x91u, 0xc0u, 0xc5u, 0xcbu, 0xf5u, 0xf6u))        // these are updated by IRQ
+            }
+            ZeropageType.KERNALSAFE -> {
+                free.addAll(0x80u..0xffu)       // TODO
+            }
+            ZeropageType.BASICSAFE,
+            ZeropageType.FLOATSAFE -> {
+                free.addAll(0x80u..0xffu)       // TODO
+                free.removeAll(0xd4u .. 0xefu)      // floating point storage
+            }
+            ZeropageType.DONTUSE -> {
+                free.clear()  // don't use zeropage at all
+            }
+        }
+
+        removeReservedFromFreePool()
+    }
+}

codeGenTargets/src/prog8/codegen/target/c128/C128MachineDefinition.kt

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

codeGenTargets/src/prog8/codegen/target/c128/C128Zeropage.kt

@@ -0,0 +1,42 @@
+package prog8.codegen.target.c128
+
+import prog8.compilerinterface.CompilationOptions
+import prog8.compilerinterface.InternalCompilerException
+import prog8.compilerinterface.Zeropage
+import prog8.compilerinterface.ZeropageType
+
+class C128Zeropage(options: CompilationOptions) : Zeropage(options) {
+
+    override val SCRATCH_B1 = 0x9bu      // temp storage for a single byte
+    override val SCRATCH_REG = 0x9cu     // temp storage for a register, must be B1+1
+    override val SCRATCH_W1 = 0xfbu      // temp storage 1 for a word  $fb+$fc
+    override val SCRATCH_W2 = 0xfdu      // temp storage 2 for a word  $fd+$fe
+
+
+    init {
+        if (options.floats && options.zeropage !in arrayOf(
+                ZeropageType.FLOATSAFE,
+                ZeropageType.BASICSAFE,
+                ZeropageType.DONTUSE
+            ))
+            throw InternalCompilerException("when floats are enabled, zero page type should be 'floatsafe' or 'basicsafe' or 'dontuse'")
+
+        when (options.zeropage) {
+            ZeropageType.FULL -> {
+                // TODO all c128 usable zero page locations, except the ones used by the system's IRQ routine
+                free.addAll(0x0au..0xffu)       // TODO c128 what about $02-$09?
+                // TODO c128  free.removeAll(setOf(0xa0u, 0xa1u, 0xa2u, 0x91u, 0xc0u, 0xc5u, 0xcbu, 0xf5u, 0xf6u))        // these are updated by IRQ
+            }
+            ZeropageType.KERNALSAFE,
+            ZeropageType.FLOATSAFE,
+            ZeropageType.BASICSAFE -> {
+                free.clear()   // TODO c128 usable zero page addresses
+            }
+            ZeropageType.DONTUSE -> {
+                free.clear()  // don't use zeropage at all
+            }
+        }
+
+        removeReservedFromFreePool()
+    }
+}

codeGenTargets/src/prog8/codegen/target/c64/C64MachineDefinition.kt

@@ -0,0 +1,76 @@
+package prog8.codegen.target.c64
+
+import prog8.codegen.target.cbm.Mflpt5
+import prog8.compilerinterface.*
+import java.io.IOException
+import java.nio.file.Path
+
+
+class C64MachineDefinition: IMachineDefinition {
+
+    override val cpu = CpuType.CPU6502
+
+    override val FLOAT_MAX_POSITIVE = Mflpt5.FLOAT_MAX_POSITIVE
+    override val FLOAT_MAX_NEGATIVE = Mflpt5.FLOAT_MAX_NEGATIVE
+    override val FLOAT_MEM_SIZE = Mflpt5.FLOAT_MEM_SIZE
+    override val PROGRAM_LOAD_ADDRESS = 0x0801u
+
+    // the 2*256 byte evaluation stack (on which bytes, words, and even floats are stored during calculations)
+    override val ESTACK_LO = 0xce00u     //  $ce00-$ceff inclusive
+    override val ESTACK_HI = 0xcf00u     //  $ce00-$ceff inclusive
+
+    override lateinit var zeropage: Zeropage
+
+    override fun getFloat(num: Number) = Mflpt5.fromNumber(num)
+
+    override fun importLibs(compilerOptions: CompilationOptions, compilationTargetName: String): List<String> {
+        return if (compilerOptions.launcher == CbmPrgLauncherType.BASIC || compilerOptions.output == OutputType.PRG)
+            listOf("syslib")
+        else
+            emptyList()
+    }
+
+    override fun launchEmulator(selectedEmulator: Int, programNameWithPath: Path) {
+        if(selectedEmulator!=1) {
+            System.err.println("The c64 target only supports the main emulator (Vice).")
+            return
+        }
+
+        for(emulator in listOf("x64sc", "x64")) {
+            println("\nStarting C-64 emulator $emulator...")
+            val viceMonlist = viceMonListName(programNameWithPath.toString())
+            val cmdline = listOf(emulator, "-silent", "-moncommands", viceMonlist,
+                    "-autostartprgmode", "1", "-autostart-warp", "-autostart", "${programNameWithPath}.prg")
+            val processb = ProcessBuilder(cmdline).inheritIO()
+            val process: Process
+            try {
+                process=processb.start()
+            } catch(x: IOException) {
+                continue  // try the next emulator executable
+            }
+            process.waitFor()
+            break
+        }
+    }
+
+    override fun isIOAddress(address: UInt): Boolean = address==0u || address==1u || address in 0xd000u..0xdfffu
+
+    override fun initializeZeropage(compilerOptions: CompilationOptions) {
+        zeropage = C64Zeropage(compilerOptions)
+    }
+
+    override val opcodeNames = normal6502instructions
+}
+
+
+// 6502 opcodes (including aliases and illegal opcodes), these cannot be used as variable or label names
+internal val normal6502instructions = setOf(
+    "adc", "ahx", "alr", "anc", "and", "ane", "arr", "asl", "asr", "axs", "bcc", "bcs",
+    "beq", "bge", "bit", "blt", "bmi", "bne", "bpl", "brk", "bvc", "bvs", "clc",
+    "cld", "cli", "clv", "cmp", "cpx", "cpy", "dcm", "dcp", "dec", "dex", "dey",
+    "eor", "gcc", "gcs", "geq", "gge", "glt", "gmi", "gne", "gpl", "gvc", "gvs",
+    "inc", "ins", "inx", "iny", "isb", "isc", "jam", "jmp", "jsr", "lae", "las",
+    "lax", "lda", "lds", "ldx", "ldy", "lsr", "lxa", "nop", "ora", "pha", "php",
+    "pla", "plp", "rla", "rol", "ror", "rra", "rti", "rts", "sax", "sbc", "sbx",
+    "sec", "sed", "sei", "sha", "shl", "shr", "shs", "shx", "shy", "slo", "sre",
+    "sta", "stx", "sty", "tas", "tax", "tay", "tsx", "txa", "txs", "tya", "xaa")

codeGenTargets/src/prog8/codegen/target/c64/C64Zeropage.kt

@@ -0,0 +1,73 @@
+package prog8.codegen.target.c64
+
+import prog8.compilerinterface.CompilationOptions
+import prog8.compilerinterface.InternalCompilerException
+import prog8.compilerinterface.Zeropage
+import prog8.compilerinterface.ZeropageType
+
+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(
+                        0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10, 0x11,
+                        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(
+                        0x22, 0x23, 0x24, 0x25,
+                        0x10, 0x11, 0x12, 0x26, 0x27, 0x28, 0x29, 0x2a,
+                        0x57, 0x58, 0x59, 0x5a, 0x5b, 0x5c, 0x5d, 0x5e, 0x5f, 0x60,
+                        0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68,
+                        0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f, 0x70, 0x71, 0x72,
+                        0x8b, 0x8c, 0x8d, 0x8e, 0x8f, 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(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()
+            }
+        }
+
+        removeReservedFromFreePool()
+    }
+}

codeGenTargets/src/prog8/codegen/target/cbm/AsmsubHelpers.kt

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

codeGenTargets/src/prog8/codegen/target/cbm/AtasciiEncoding.kt

@@ -0,0 +1,204 @@
+package prog8.codegen.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> {
+        return Ok(str.map { encodeTable.getValue(it).toUByte() })
+    }
+
+    fun decode(bytes: List<UByte>): Result<String, CharConversionException> {
+        return Ok(bytes.map { decodeTable[it.toInt()] }.joinToString(""))
+    }
+}

codeGenTargets/src/prog8/codegen/target/cbm/CbmMemorySizer.kt

@@ -0,0 +1,31 @@
+package prog8.codegen.target.cbm
+
+import prog8.ast.base.*
+import prog8.ast.expressions.StringLiteral
+import prog8.ast.statements.VarDecl
+import prog8.compilerinterface.IMemSizer
+
+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(decl: VarDecl): Int {
+        return when(decl.type) {
+            VarDeclType.CONST -> 0
+            VarDeclType.VAR, VarDeclType.MEMORY -> {
+                when(val dt = decl.datatype) {
+                    in NumericDatatypes -> return memorySize(dt)
+                    in ArrayDatatypes -> decl.arraysize!!.constIndex()!! * memorySize(ArrayToElementTypes.getValue(dt))
+                    DataType.STR -> (decl.value as StringLiteral).value.length + 1
+                    else -> 0
+                }
+            }
+        }
+    }
+}

codeGenTargets/src/prog8/codegen/target/cbm/IsoEncoding.kt

@@ -0,0 +1,27 @@
+package prog8.codegen.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 {
+            Ok(str.toByteArray(charset).map { it.toUByte() })
+        } catch (ce: CharConversionException) {
+            Err(ce)
+        }
+    }
+
+    fun decode(bytes: List<UByte>): Result<String, CharConversionException> {
+        return try {
+            Ok(String(bytes.map { it.toByte() }.toByteArray(), charset))
+        } catch (ce: CharConversionException) {
+            Err(ce)
+        }
+    }
+}

codeGenTargets/src/prog8/codegen/target/cbm/Mflpt5.kt

@@ -0,0 +1,78 @@
+package prog8.codegen.target.cbm
+
+import prog8.compilerinterface.IMachineFloat
+import prog8.compilerinterface.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): IMachineFloat {
+
+    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: $this")
+                exponent == 0 -> zero
+                else -> {
+                    val mantLong = mantissa.toLong()
+                    Mflpt5(
+                        exponent.toUByte(),
+                        (mantLong.and(0x7f000000L) ushr 24).or(sign).toUByte(),
+                        (mantLong.and(0x00ff0000L) ushr 16).toUByte(),
+                        (mantLong.and(0x0000ff00L) ushr 8).toUByte(),
+                        (mantLong.and(0x000000ffL)).toUByte()
+                    )
+                }
+            }
+        }
+    }
+
+    override fun toDouble(): Double {
+        if (this == zero) return 0.0
+        val exp = b0.toInt() - 128
+        val sign = (b1.toInt() and 0x80) > 0
+        val number = 0x80000000L.or(b1.toLong() shl 24).or(b2.toLong() shl 16).or(b3.toLong() shl 8).or(b4.toLong())
+        val result = number.toDouble() * (2.0).pow(exp) / 0x100000000
+        return if (sign) -result else result
+    }
+
+    override fun makeFloatFillAsm(): String {
+        val b0 = "$" + b0.toString(16).padStart(2, '0')
+        val b1 = "$" + b1.toString(16).padStart(2, '0')
+        val b2 = "$" + b2.toString(16).padStart(2, '0')
+        val b3 = "$" + b3.toString(16).padStart(2, '0')
+        val b4 = "$" + b4.toString(16).padStart(2, '0')
+        return "$b0, $b1, $b2, $b3, $b4"
+    }
+}

codeGenTargets/src/prog8/codegen/target/cx16/CX16MachineDefinition.kt

@@ -0,0 +1,77 @@
+package prog8.codegen.target.cx16
+
+import prog8.codegen.target.cbm.Mflpt5
+import prog8.compilerinterface.*
+import java.nio.file.Path
+
+
+class CX16MachineDefinition: IMachineDefinition {
+
+    override val cpu = CpuType.CPU65c02
+
+    override val FLOAT_MAX_POSITIVE = Mflpt5.FLOAT_MAX_POSITIVE
+    override val FLOAT_MAX_NEGATIVE = Mflpt5.FLOAT_MAX_NEGATIVE
+    override val FLOAT_MEM_SIZE = Mflpt5.FLOAT_MEM_SIZE
+    override val PROGRAM_LOAD_ADDRESS = 0x0801u
+
+    // the 2*256 byte evaluation stack (on which bytes, words, and even floats are stored during calculations)
+    override val ESTACK_LO = 0x0400u        //  $0400-$04ff inclusive
+    override val ESTACK_HI = 0x0500u        //  $0500-$05ff inclusive
+
+    override lateinit var zeropage: Zeropage
+
+    override fun getFloat(num: Number) = Mflpt5.fromNumber(num)
+    override fun importLibs(compilerOptions: CompilationOptions, compilationTargetName: String): List<String> {
+        return if (compilerOptions.launcher == CbmPrgLauncherType.BASIC || compilerOptions.output == OutputType.PRG)
+            listOf("syslib")
+        else
+            emptyList()
+    }
+
+    override fun launchEmulator(selectedEmulator: Int, programNameWithPath: Path) {
+        val emulator: String
+        val extraArgs: List<String>
+
+        when(selectedEmulator) {
+            1 -> {
+                emulator = "x16emu"
+                extraArgs = emptyList()
+            }
+            2 -> {
+                emulator = "box16"
+                extraArgs = listOf("-sym", viceMonListName(programNameWithPath.toString()))
+            }
+            else -> {
+                System.err.println("Cx16 target only supports x16emu and box16 emulators.")
+                return
+            }
+        }
+
+        println("\nStarting Commander X16 emulator $emulator...")
+        val cmdline = listOf(emulator, "-scale", "2", "-run", "-prg", "${programNameWithPath}.prg") + extraArgs
+        val processb = ProcessBuilder(cmdline).inheritIO()
+        val process: Process = processb.start()
+        process.waitFor()
+    }
+
+    override fun isIOAddress(address: UInt): Boolean = address==0u || address==1u || address in 0x9f00u..0x9fffu
+
+    override fun initializeZeropage(compilerOptions: CompilationOptions) {
+        zeropage = CX16Zeropage(compilerOptions)
+    }
+
+    // 6502 opcodes (including aliases and illegal opcodes), these cannot be used as variable or label names
+    override val opcodeNames = setOf("adc", "and", "asl", "bcc", "bcs",
+            "beq", "bge", "bit", "blt", "bmi", "bne", "bpl", "brk", "bvc", "bvs", "clc",
+            "cld", "cli", "clv", "cmp", "cpx", "cpy", "dec", "dex", "dey",
+            "eor", "gcc", "gcs", "geq", "gge", "glt", "gmi", "gne", "gpl", "gvc", "gvs",
+            "inc", "inx", "iny", "jmp", "jsr",
+            "lda", "ldx", "ldy", "lsr", "nop", "ora", "pha", "php",
+            "pla", "plp", "rol", "ror", "rti", "rts", "sbc",
+            "sec", "sed", "sei",
+            "sta", "stx", "sty", "tax", "tay", "tsx", "txa", "txs", "tya",
+            "bra", "phx", "phy", "plx", "ply", "stz", "trb", "tsb", "bbr", "bbs",
+            "rmb", "smb", "stp", "wai")
+
+
+}

codeGenTargets/src/prog8/codegen/target/cx16/CX16Zeropage.kt

@@ -0,0 +1,57 @@
+package prog8.codegen.target.cx16
+
+import prog8.ast.GlobalNamespace
+import prog8.ast.base.DataType
+import prog8.compilerinterface.CompilationOptions
+import prog8.compilerinterface.InternalCompilerException
+import prog8.compilerinterface.Zeropage
+import prog8.compilerinterface.ZeropageType
+
+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.BASICSAFE, ZeropageType.DONTUSE))
+            throw InternalCompilerException("when floats are enabled, zero page type should be 'basicsafe' or 'dontuse'")
+
+        // the addresses 0x02 to 0x21 (inclusive) are taken for sixteen virtual 16-bit api registers.
+
+        synchronized(this) {
+            when (options.zeropage) {
+                ZeropageType.FULL -> {
+                    free.addAll(0x22u..0xffu)
+                }
+                ZeropageType.KERNALSAFE -> {
+                    free.addAll(0x22u..0x7fu)
+                    free.addAll(0xa9u..0xffu)
+                }
+                ZeropageType.BASICSAFE -> {
+                    free.addAll(0x22u..0x7fu)
+                }
+                ZeropageType.DONTUSE -> {
+                    free.clear() // don't use zeropage at all
+                }
+                else -> throw InternalCompilerException("for this machine target, zero page type 'floatsafe' is not available. ${options.zeropage}")
+            }
+
+            removeReservedFromFreePool()
+
+            // note: the 16 virtual registers R0-R15 are not regular allocated variables, they're *memory mapped* elsewhere to fixed addresses.
+            // however, to be able for the compiler to "see" them as zero page variables, we have to register them here as well.
+            val dummyscope = GlobalNamespace(emptyList())
+            for(reg in 0..15) {
+                allocatedVariables[listOf("cx16", "r${reg}")]   = ZpAllocation((2+reg*2).toUInt(), DataType.UWORD, 2, dummyscope, null, null)        // cx16.r0 .. cx16.r15
+                allocatedVariables[listOf("cx16", "r${reg}s")]  = ZpAllocation((2+reg*2).toUInt(), DataType.WORD, 2, dummyscope, null, null)        // cx16.r0s .. cx16.r15s
+                allocatedVariables[listOf("cx16", "r${reg}L")]  = ZpAllocation((2+reg*2).toUInt(), DataType.UBYTE, 1, dummyscope, null, null)       // cx16.r0L .. cx16.r15L
+                allocatedVariables[listOf("cx16", "r${reg}H")]  = ZpAllocation((3+reg*2).toUInt(), DataType.UBYTE, 1, dummyscope, null, null)       // cx16.r0H .. cx16.r15H
+                allocatedVariables[listOf("cx16", "r${reg}sL")] = ZpAllocation((2+reg*2).toUInt(), DataType.BYTE, 1, dummyscope, null, null)       // cx16.r0sL .. cx16.r15sL
+                allocatedVariables[listOf("cx16", "r${reg}sH")] = ZpAllocation((3+reg*2).toUInt(), DataType.BYTE, 1, dummyscope, null, null)       // cx16.r0sH .. cx16.r15sH
+            }
+        }
+    }
+}

codeOptimizers/build.gradle

@@ -0,0 +1,44 @@
+
+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(':compilerInterfaces')
+    implementation project(':compilerAst')
+    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8"
+    // implementation "org.jetbrains.kotlin:kotlin-reflect"
+}
+
+sourceSets {
+    main {
+        java {
+            srcDirs = ["${project.projectDir}/src"]
+        }
+        resources {
+            srcDirs = ["${project.projectDir}/res"]
+        }
+    }
+}
+
+// note: there are no unit tests in this module!

codeOptimizers/codeOptimizers.iml

@@ -0,0 +1,15 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<module type="JAVA_MODULE" version="4">
+  <component name="NewModuleRootManager" inherit-compiler-output="true">
+    <exclude-output />
+    <content url="file://$MODULE_DIR$">
+      <sourceFolder url="file://$MODULE_DIR$/src" isTestSource="false" />
+      <excludeFolder url="file://$MODULE_DIR$/build" />
+    </content>
+    <orderEntry type="inheritedJdk" />
+    <orderEntry type="sourceFolder" forTests="false" />
+    <orderEntry type="library" name="KotlinJavaRuntime" level="project" />
+    <orderEntry type="module" module-name="compilerInterfaces" />
+    <orderEntry type="module" module-name="compilerAst" />
+  </component>
+</module>

codeOptimizers/readme-tests.txt

@@ -0,0 +1,2 @@
+Unittests for things in this module are located in the Compiler module instead,
+for convenience sake, and to not spread the test cases around too much.

codeOptimizers/src/prog8/optimizer/BinExprSplitter.kt

@@ -0,0 +1,122 @@
+package prog8.optimizer
+
+import prog8.ast.IStatementContainer
+import prog8.ast.Node
+import prog8.ast.Program
+import prog8.ast.base.DataType
+import prog8.ast.expressions.AugmentAssignmentOperators
+import prog8.ast.expressions.BinaryExpression
+import prog8.ast.expressions.IdentifierReference
+import prog8.ast.expressions.TypecastExpression
+import prog8.ast.getTempVar
+import prog8.ast.statements.AssignTarget
+import prog8.ast.statements.Assignment
+import prog8.ast.statements.AssignmentOrigin
+import prog8.ast.walk.AstWalker
+import prog8.ast.walk.IAstModification
+import prog8.compilerinterface.CompilationOptions
+import prog8.compilerinterface.ICompilationTarget
+import prog8.compilerinterface.isIOAddress
+
+
+class BinExprSplitter(private val program: Program, private val options: CompilationOptions, private val compTarget: ICompilationTarget) : AstWalker() {
+
+    override fun after(assignment: Assignment, parent: Node): Iterable<IAstModification> {
+
+        if(assignment.value.inferType(program) istype DataType.FLOAT && !options.optimizeFloatExpressions)
+            return noModifications
+
+        val binExpr = assignment.value as? BinaryExpression
+        if (binExpr != null) {
+
+/*
+
+Reduce the complexity of a (binary) expression that has to be evaluated on the eval stack,
+by attempting to splitting it up into individual simple steps.
+We only consider a binary expression *one* level deep (so the operands must not be a combined expression)
+
+
+X =      BinExpr                                    X   =   LeftExpr
+        <operator>                                     followed by
+          /   \             IF 'X' not used         X   =   BinExpr
+         /     \             IN expression ==>             <operator>
+        /       \                                           /   \
+    LeftExpr.  RightExpr.                                  /     \
+                                                          X     RightExpr.
+
+
+ */
+            if(binExpr.operator in AugmentAssignmentOperators && isSimpleTarget(assignment.target)) {
+                if(assignment.target isSameAs binExpr.right)
+                    return noModifications
+                if(assignment.target isSameAs binExpr.left) {
+                    if(binExpr.right.isSimple)
+                        return noModifications
+                    val leftBx = binExpr.left as? BinaryExpression
+                    if(leftBx!=null && (!leftBx.left.isSimple || !leftBx.right.isSimple))
+                        return noModifications
+                    val rightBx = binExpr.right as? BinaryExpression
+                    if(rightBx!=null && (!rightBx.left.isSimple || !rightBx.right.isSimple))
+                        return noModifications
+
+                      // TODO below attempts to remove stack-based evaluated expressions, but often the resulting code is BIGGER, and SLOWER.
+//                    val dt = assignment.target.inferType(program)
+//                    if(!dt.isInteger)
+//                        return noModifications
+//                    val tempVar = IdentifierReference(getTempVarName(dt), binExpr.right.position)
+//                    val assignTempVar = Assignment(
+//                        AssignTarget(tempVar, null, null, binExpr.right.position),
+//                        binExpr.right, binExpr.right.position
+//                    )
+//                    return listOf(
+//                        IAstModification.InsertBefore(assignment, assignTempVar, assignment.parent as IStatementContainer),
+//                        IAstModification.ReplaceNode(binExpr.right, tempVar.copy(), binExpr)
+//                    )
+                }
+
+                if(binExpr.right.isSimple) {
+                    val firstAssign = Assignment(assignment.target.copy(), binExpr.left, AssignmentOrigin.OPTIMIZER, binExpr.left.position)
+                    val targetExpr = assignment.target.toExpression()
+                    val augExpr = BinaryExpression(targetExpr, binExpr.operator, binExpr.right, binExpr.right.position)
+                    return listOf(
+                        IAstModification.ReplaceNode(binExpr, augExpr, assignment),
+                        IAstModification.InsertBefore(assignment, firstAssign, assignment.parent as IStatementContainer)
+                    )
+                }
+            }
+
+            // TODO further unraveling of binary expression trees into flat statements.
+            // however this should probably be done in a more generic way to also work on
+            // the expressiontrees that are not used in an assignment statement...
+        }
+
+        val typecast = assignment.value as? TypecastExpression
+        if(typecast!=null) {
+            val origExpr = typecast.expression as? BinaryExpression
+            if(origExpr!=null) {
+                // it's a typecast of a binary expression.
+                // we can see if we can unwrap the binary expression by working on a new temporary variable
+                // (that has the type of the expression), and then finally doing the typecast.
+                // Once it's outside the typecast, the regular splitting can commence.
+                val (tempVarName, _) = program.getTempVar(origExpr.inferType(program).getOr(DataType.UNDEFINED))
+                val assignTempVar = Assignment(
+                    AssignTarget(IdentifierReference(tempVarName, typecast.position), null, null, typecast.position),
+                    typecast.expression, AssignmentOrigin.OPTIMIZER, typecast.position
+                )
+                return listOf(
+                    IAstModification.InsertBefore(assignment, assignTempVar, parent as IStatementContainer),
+                    IAstModification.ReplaceNode(typecast.expression, IdentifierReference(tempVarName, typecast.position), typecast)
+                )
+            }
+        }
+
+        return noModifications
+    }
+
+    private fun isSimpleTarget(target: AssignTarget) =
+            if (target.identifier!=null || target.memoryAddress!=null)
+                !target.isIOAddress(compTarget.machine)
+            else
+                false
+
+}

codeOptimizers/src/prog8/optimizer/ConstExprEvaluator.kt

@@ -0,0 +1,278 @@
+package prog8.optimizer
+
+import prog8.ast.base.*
+import prog8.ast.expressions.Expression
+import prog8.ast.expressions.NumericLiteral
+import kotlin.math.pow
+
+
+class ConstExprEvaluator {
+
+    fun evaluate(left: NumericLiteral, operator: String, right: NumericLiteral): Expression {
+        try {
+            return when(operator) {
+                "+" -> plus(left, right)
+                "-" -> minus(left, right)
+                "*" -> multiply(left, right)
+                "/" -> divide(left, right)
+                "%" -> remainder(left, right)
+                "**" -> power(left, right)
+                "&" -> bitwiseand(left, right)
+                "|" -> bitwiseor(left, right)
+                "^" -> bitwisexor(left, right)
+                "and" -> logicaland(left, right)
+                "or" -> logicalor(left, right)
+                "xor" -> logicalxor(left, right)
+                "<" -> NumericLiteral.fromBoolean(left < right, left.position)
+                ">" -> NumericLiteral.fromBoolean(left > right, left.position)
+                "<=" -> NumericLiteral.fromBoolean(left <= right, left.position)
+                ">=" -> NumericLiteral.fromBoolean(left >= right, left.position)
+                "==" -> NumericLiteral.fromBoolean(left == right, left.position)
+                "!=" -> NumericLiteral.fromBoolean(left != right, left.position)
+                "<<" -> shiftedleft(left, right)
+                ">>" -> shiftedright(left, right)
+                else -> throw FatalAstException("const evaluation for invalid operator $operator")
+            }
+        } catch (ax: FatalAstException) {
+            throw ExpressionError(ax.message, left.position)
+        }
+    }
+
+    private fun shiftedright(left: NumericLiteral, amount: NumericLiteral): Expression {
+        if(left.type !in IntegerDatatypes || amount.type !in IntegerDatatypes)
+            throw ExpressionError("cannot compute $left >> $amount", left.position)
+        val result =
+                if(left.type== DataType.UBYTE || left.type== DataType.UWORD)
+                    left.number.toInt().ushr(amount.number.toInt())
+                else
+                    left.number.toInt().shr(amount.number.toInt())
+        return NumericLiteral(left.type, result.toDouble(), left.position)
+    }
+
+    private fun shiftedleft(left: NumericLiteral, amount: NumericLiteral): Expression {
+        if(left.type !in IntegerDatatypes || amount.type !in IntegerDatatypes)
+            throw ExpressionError("cannot compute $left << $amount", left.position)
+        val result = left.number.toInt().shl(amount.number.toInt())
+        return NumericLiteral(left.type, result.toDouble(), left.position)
+    }
+
+    private fun logicalxor(left: NumericLiteral, right: NumericLiteral): NumericLiteral {
+        val error = "cannot compute $left locical-bitxor $right"
+        return when (left.type) {
+            in IntegerDatatypes -> when (right.type) {
+                in IntegerDatatypes -> NumericLiteral.fromBoolean((left.number.toInt() != 0) xor (right.number.toInt() != 0), left.position)
+                DataType.FLOAT -> NumericLiteral.fromBoolean((left.number.toInt() != 0) xor (right.number != 0.0), left.position)
+                else -> throw ExpressionError(error, left.position)
+            }
+            DataType.FLOAT -> when (right.type) {
+                in IntegerDatatypes -> NumericLiteral.fromBoolean((left.number != 0.0) xor (right.number.toInt() != 0), left.position)
+                DataType.FLOAT -> NumericLiteral.fromBoolean((left.number != 0.0) xor (right.number != 0.0), left.position)
+                else -> throw ExpressionError(error, left.position)
+            }
+            else -> throw ExpressionError(error, left.position)
+        }
+    }
+
+    private fun logicalor(left: NumericLiteral, right: NumericLiteral): NumericLiteral {
+        val error = "cannot compute $left locical-or $right"
+        return when (left.type) {
+            in IntegerDatatypes -> when (right.type) {
+                in IntegerDatatypes -> NumericLiteral.fromBoolean(left.number.toInt() != 0 || right.number.toInt() != 0, left.position)
+                DataType.FLOAT -> NumericLiteral.fromBoolean(left.number.toInt() != 0 || right.number != 0.0, left.position)
+                else -> throw ExpressionError(error, left.position)
+            }
+            DataType.FLOAT -> when (right.type) {
+                in IntegerDatatypes -> NumericLiteral.fromBoolean(left.number != 0.0 || right.number.toInt() != 0, left.position)
+                DataType.FLOAT -> NumericLiteral.fromBoolean(left.number != 0.0 || right.number != 0.0, left.position)
+                else -> throw ExpressionError(error, left.position)
+            }
+            else -> throw ExpressionError(error, left.position)
+        }
+    }
+
+    private fun logicaland(left: NumericLiteral, right: NumericLiteral): NumericLiteral {
+        val error = "cannot compute $left locical-and $right"
+        return when (left.type) {
+            in IntegerDatatypes -> when (right.type) {
+                in IntegerDatatypes -> NumericLiteral.fromBoolean(left.number.toInt() != 0 && right.number.toInt() != 0, left.position)
+                DataType.FLOAT -> NumericLiteral.fromBoolean(left.number.toInt() != 0 && right.number != 0.0, left.position)
+                else -> throw ExpressionError(error, left.position)
+            }
+            DataType.FLOAT -> when (right.type) {
+                in IntegerDatatypes -> NumericLiteral.fromBoolean(left.number != 0.0 && right.number.toInt() != 0, left.position)
+                DataType.FLOAT -> NumericLiteral.fromBoolean(left.number != 0.0 && right.number != 0.0, left.position)
+                else -> throw ExpressionError(error, left.position)
+            }
+            else -> throw ExpressionError(error, left.position)
+        }
+    }
+
+    private fun bitwisexor(left: NumericLiteral, right: NumericLiteral): NumericLiteral {
+        if(left.type== DataType.UBYTE) {
+            if(right.type in IntegerDatatypes) {
+                return NumericLiteral(DataType.UBYTE, (left.number.toInt() xor (right.number.toInt() and 255)).toDouble(), left.position)
+            }
+        } else if(left.type== DataType.UWORD) {
+            if(right.type in IntegerDatatypes) {
+                return NumericLiteral(DataType.UWORD, (left.number.toInt() xor right.number.toInt()).toDouble(), left.position)
+            }
+        }
+        throw ExpressionError("cannot calculate $left ^ $right", left.position)
+    }
+
+    private fun bitwiseor(left: NumericLiteral, right: NumericLiteral): NumericLiteral {
+        if(left.type== DataType.UBYTE) {
+            if(right.type in IntegerDatatypes) {
+                return NumericLiteral(DataType.UBYTE, (left.number.toInt() or (right.number.toInt() and 255)).toDouble(), left.position)
+            }
+        } else if(left.type== DataType.UWORD) {
+            if(right.type in IntegerDatatypes) {
+                return NumericLiteral(DataType.UWORD, (left.number.toInt() or right.number.toInt()).toDouble(), left.position)
+            }
+        }
+        throw ExpressionError("cannot calculate $left | $right", left.position)
+    }
+
+    private fun bitwiseand(left: NumericLiteral, right: NumericLiteral): NumericLiteral {
+        if(left.type== DataType.UBYTE) {
+            if(right.type in IntegerDatatypes) {
+                return NumericLiteral(DataType.UBYTE, (left.number.toInt() and (right.number.toInt() and 255)).toDouble(), left.position)
+            }
+        } else if(left.type== DataType.UWORD) {
+            if(right.type in IntegerDatatypes) {
+                return NumericLiteral(DataType.UWORD, (left.number.toInt() and right.number.toInt()).toDouble(), left.position)
+            }
+        }
+        throw ExpressionError("cannot calculate $left & $right", left.position)
+    }
+
+    private fun power(left: NumericLiteral, right: NumericLiteral): NumericLiteral {
+        val error = "cannot calculate $left ** $right"
+        return when (left.type) {
+            in IntegerDatatypes -> when (right.type) {
+                in IntegerDatatypes -> NumericLiteral.optimalNumeric(left.number.toInt().toDouble().pow(right.number.toInt()), left.position)
+                DataType.FLOAT -> NumericLiteral(DataType.FLOAT, left.number.toInt().toDouble().pow(right.number), left.position)
+                else -> throw ExpressionError(error, left.position)
+            }
+            DataType.FLOAT -> when (right.type) {
+                in IntegerDatatypes -> NumericLiteral(DataType.FLOAT, left.number.pow(right.number.toInt()), left.position)
+                DataType.FLOAT -> NumericLiteral(DataType.FLOAT, left.number.pow(right.number), left.position)
+                else -> throw ExpressionError(error, left.position)
+            }
+            else -> throw ExpressionError(error, left.position)
+        }
+    }
+
+    private fun plus(left: NumericLiteral, right: NumericLiteral): NumericLiteral {
+        val error = "cannot add $left and $right"
+        return when (left.type) {
+            in IntegerDatatypes -> when (right.type) {
+                in IntegerDatatypes -> NumericLiteral.optimalInteger(left.number.toInt() + right.number.toInt(), left.position)
+                DataType.FLOAT -> NumericLiteral(DataType.FLOAT, left.number.toInt() + right.number, left.position)
+                else -> throw ExpressionError(error, left.position)
+            }
+            DataType.FLOAT -> when (right.type) {
+                in IntegerDatatypes -> NumericLiteral(DataType.FLOAT, left.number + right.number.toInt(), left.position)
+                DataType.FLOAT -> NumericLiteral(DataType.FLOAT, left.number + right.number, left.position)
+                else -> throw ExpressionError(error, left.position)
+            }
+            else -> throw ExpressionError(error, left.position)
+        }
+    }
+
+    private fun minus(left: NumericLiteral, right: NumericLiteral): NumericLiteral {
+        val error = "cannot subtract $left and $right"
+        return when (left.type) {
+            in IntegerDatatypes -> when (right.type) {
+                in IntegerDatatypes -> NumericLiteral.optimalInteger(left.number.toInt() - right.number.toInt(), left.position)
+                DataType.FLOAT -> NumericLiteral(DataType.FLOAT, left.number.toInt() - right.number, left.position)
+                else -> throw ExpressionError(error, left.position)
+            }
+            DataType.FLOAT -> when (right.type) {
+                in IntegerDatatypes -> NumericLiteral(DataType.FLOAT, left.number - right.number.toInt(), left.position)
+                DataType.FLOAT -> NumericLiteral(DataType.FLOAT, left.number - right.number, left.position)
+                else -> throw ExpressionError(error, left.position)
+            }
+            else -> throw ExpressionError(error, left.position)
+        }
+    }
+
+    private fun multiply(left: NumericLiteral, right: NumericLiteral): NumericLiteral {
+        val error = "cannot multiply ${left.type} and ${right.type}"
+        return when (left.type) {
+            in IntegerDatatypes -> when (right.type) {
+                in IntegerDatatypes -> NumericLiteral.optimalInteger(left.number.toInt() * right.number.toInt(), left.position)
+                DataType.FLOAT -> NumericLiteral(DataType.FLOAT, left.number.toInt() * right.number, left.position)
+                else -> throw ExpressionError(error, left.position)
+            }
+            DataType.FLOAT -> when (right.type) {
+                in IntegerDatatypes -> NumericLiteral(DataType.FLOAT, left.number * right.number.toInt(), left.position)
+                DataType.FLOAT -> NumericLiteral(DataType.FLOAT, left.number * right.number, left.position)
+                else -> throw ExpressionError(error, left.position)
+            }
+            else -> throw ExpressionError(error, left.position)
+        }
+    }
+
+    private fun divideByZeroError(pos: Position): Unit =
+            throw ExpressionError("division by zero", pos)
+
+    private fun divide(left: NumericLiteral, right: NumericLiteral): NumericLiteral {
+        val error = "cannot divide $left by $right"
+        return when (left.type) {
+            in IntegerDatatypes -> when (right.type) {
+                in IntegerDatatypes -> {
+                    if(right.number.toInt()==0) divideByZeroError(right.position)
+                    val result: Int = left.number.toInt() / right.number.toInt()
+                    NumericLiteral.optimalInteger(result, left.position)
+                }
+                DataType.FLOAT -> {
+                    if(right.number==0.0) divideByZeroError(right.position)
+                    NumericLiteral(DataType.FLOAT, left.number.toInt() / right.number, left.position)
+                }
+                else -> throw ExpressionError(error, left.position)
+            }
+            DataType.FLOAT -> when (right.type) {
+                in IntegerDatatypes -> {
+                    if(right.number.toInt()==0) divideByZeroError(right.position)
+                    NumericLiteral(DataType.FLOAT, left.number / right.number.toInt(), left.position)
+                }
+                DataType.FLOAT -> {
+                    if(right.number ==0.0) divideByZeroError(right.position)
+                    NumericLiteral(DataType.FLOAT, left.number / right.number, left.position)
+                }
+                else -> throw ExpressionError(error, left.position)
+            }
+            else -> throw ExpressionError(error, left.position)
+        }
+    }
+
+    private fun remainder(left: NumericLiteral, right: NumericLiteral): NumericLiteral {
+        val error = "cannot compute remainder of $left by $right"
+        return when (left.type) {
+            in IntegerDatatypes -> when (right.type) {
+                in IntegerDatatypes -> {
+                    if(right.number.toInt()==0) divideByZeroError(right.position)
+                    NumericLiteral.optimalNumeric(left.number.toInt().toDouble() % right.number.toInt().toDouble(), left.position)
+                }
+                DataType.FLOAT -> {
+                    if(right.number ==0.0) divideByZeroError(right.position)
+                    NumericLiteral(DataType.FLOAT, left.number.toInt() % right.number, left.position)
+                }
+                else -> throw ExpressionError(error, left.position)
+            }
+            DataType.FLOAT -> when (right.type) {
+                in IntegerDatatypes -> {
+                    if(right.number.toInt()==0) divideByZeroError(right.position)
+                    NumericLiteral(DataType.FLOAT, left.number % right.number.toInt(), left.position)
+                }
+                DataType.FLOAT -> {
+                    if(right.number ==0.0) divideByZeroError(right.position)
+                    NumericLiteral(DataType.FLOAT, left.number % right.number, left.position)
+                }
+                else -> throw ExpressionError(error, left.position)
+            }
+            else -> throw ExpressionError(error, left.position)
+        }
+    }
+}

codeOptimizers/src/prog8/optimizer/ConstantFoldingOptimizer.kt

@@ -4,183 +4,15 @@ import prog8.ast.Node
 import prog8.ast.Program
 import prog8.ast.base.*
 import prog8.ast.expressions.*
-import prog8.ast.processing.AstWalker
-import prog8.ast.processing.IAstModification
-import prog8.ast.statements.*
-import prog8.compiler.target.CompilationTarget
+import prog8.ast.statements.Assignment
+import prog8.ast.statements.ForLoop
+import prog8.ast.statements.VarDecl
+import prog8.ast.walk.AstWalker
+import prog8.ast.walk.IAstModification
+import kotlin.math.pow
 
 
-// First thing to do is replace all constant identifiers with their actual value,
-// and the array var initializer values and sizes.
-// This is needed because further constant optimizations depend on those.
-internal class ConstantIdentifierReplacer(private val program: Program, private val errors: ErrorReporter) : AstWalker() {
-    private val noModifications = emptyList<IAstModification>()
-
-    override fun after(identifier: IdentifierReference, parent: Node): Iterable<IAstModification> {
-        // replace identifiers that refer to const value, with the value itself
-        // if it's a simple type and if it's not a left hand side variable
-        if(identifier.parent is AssignTarget)
-            return noModifications
-        var forloop = identifier.parent as? ForLoop
-        if(forloop==null)
-            forloop = identifier.parent.parent as? ForLoop
-        if(forloop!=null && identifier===forloop.loopVar)
-            return noModifications
-
-        val cval = identifier.constValue(program) ?: return noModifications
-        return when (cval.type) {
-            in NumericDatatypes -> listOf(IAstModification.ReplaceNode(identifier, NumericLiteralValue(cval.type, cval.number, identifier.position), identifier.parent))
-            in PassByReferenceDatatypes -> throw FatalAstException("pass-by-reference type should not be considered a constant")
-            else -> noModifications
-        }
-    }
-
-    override fun before(decl: VarDecl, parent: Node): Iterable<IAstModification> {
-        // the initializer value can't refer to the variable itself (recursive definition)
-        // TODO: use call graph for this?
-        if(decl.value?.referencesIdentifiers(decl.name) == true || decl.arraysize?.index?.referencesIdentifiers(decl.name) == true) {
-            errors.err("recursive var declaration", decl.position)
-            return noModifications
-        }
-
-        if(decl.type==VarDeclType.CONST || decl.type==VarDeclType.VAR) {
-            if(decl.isArray){
-                if(decl.arraysize==null) {
-                    // for arrays that have no size specifier (or a non-constant one) attempt to deduce the size
-                    val arrayval = decl.value as? ArrayLiteralValue
-                    if(arrayval!=null) {
-                        return listOf(IAstModification.SetExpression(
-                                { decl.arraysize = ArrayIndex(it, decl.position) },
-                                NumericLiteralValue.optimalInteger(arrayval.value.size, decl.position),
-                                decl
-                        ))
-                    }
-                }
-                else if(decl.arraysize?.size()==null) {
-                    val size = decl.arraysize!!.index.constValue(program)
-                    if(size!=null) {
-                        return listOf(IAstModification.SetExpression(
-                                { decl.arraysize = ArrayIndex(it, decl.position) },
-                                size, decl
-                        ))
-                    }
-                }
-            }
-
-            when(decl.datatype) {
-                DataType.FLOAT -> {
-                    // vardecl: for scalar float vars, promote constant integer initialization values to floats
-                    val litval = decl.value as? NumericLiteralValue
-                    if (litval!=null && litval.type in IntegerDatatypes) {
-                        val newValue = NumericLiteralValue(DataType.FLOAT, litval.number.toDouble(), litval.position)
-                        return listOf(IAstModification.ReplaceNode(decl.value!!, newValue, decl))
-                    }
-                }
-                DataType.ARRAY_UB, DataType.ARRAY_B, DataType.ARRAY_UW, DataType.ARRAY_W -> {
-                    val numericLv = decl.value as? NumericLiteralValue
-                    val rangeExpr = decl.value as? RangeExpr
-                    if(rangeExpr!=null) {
-                        // convert the initializer range expression to an actual array
-                        val declArraySize = decl.arraysize?.size()
-                        if(declArraySize!=null && declArraySize!=rangeExpr.size())
-                            errors.err("range expression size doesn't match declared array size", decl.value?.position!!)
-                        val constRange = rangeExpr.toConstantIntegerRange()
-                        if(constRange!=null) {
-                            val eltType = rangeExpr.inferType(program).typeOrElse(DataType.UBYTE)
-                            val newValue = if(eltType in ByteDatatypes) {
-                                ArrayLiteralValue(InferredTypes.InferredType.known(decl.datatype),
-                                        constRange.map { NumericLiteralValue(eltType, it.toShort(), decl.value!!.position) }.toTypedArray(),
-                                        position = decl.value!!.position)
-                            } else {
-                                ArrayLiteralValue(InferredTypes.InferredType.known(decl.datatype),
-                                        constRange.map { NumericLiteralValue(eltType, it, decl.value!!.position) }.toTypedArray(),
-                                        position = decl.value!!.position)
-                            }
-                            return listOf(IAstModification.ReplaceNode(decl.value!!, newValue, decl))
-                        }
-                    }
-                    if(numericLv!=null && numericLv.type==DataType.FLOAT)
-                        errors.err("arraysize requires only integers here", numericLv.position)
-                    val size = decl.arraysize?.size() ?: return noModifications
-                    if (rangeExpr==null && numericLv!=null) {
-                        // arraysize initializer is empty or a single int, and we know the size; create the arraysize.
-                        val fillvalue = numericLv.number.toInt()
-                        when(decl.datatype){
-                            DataType.ARRAY_UB -> {
-                                if(fillvalue !in 0..255)
-                                    errors.err("ubyte value overflow", numericLv.position)
-                            }
-                            DataType.ARRAY_B -> {
-                                if(fillvalue !in -128..127)
-                                    errors.err("byte value overflow", numericLv.position)
-                            }
-                            DataType.ARRAY_UW -> {
-                                if(fillvalue !in 0..65535)
-                                    errors.err("uword value overflow", numericLv.position)
-                            }
-                            DataType.ARRAY_W -> {
-                                if(fillvalue !in -32768..32767)
-                                    errors.err("word value overflow", numericLv.position)
-                            }
-                            else -> {}
-                        }
-                        // create the array itself, filled with the fillvalue.
-                        val array = Array(size) {fillvalue}.map { NumericLiteralValue(ArrayElementTypes.getValue(decl.datatype), it, numericLv.position) as Expression}.toTypedArray()
-                        val refValue = ArrayLiteralValue(InferredTypes.InferredType.known(decl.datatype), array, position = numericLv.position)
-                        return listOf(IAstModification.ReplaceNode(decl.value!!, refValue, decl))
-                    }
-                }
-                DataType.ARRAY_F  -> {
-                    val size = decl.arraysize?.size() ?: return noModifications
-                    val litval = decl.value as? NumericLiteralValue
-                    val rangeExpr = decl.value as? RangeExpr
-                    if(rangeExpr!=null) {
-                        // convert the initializer range expression to an actual array of floats
-                        val declArraySize = decl.arraysize?.size()
-                        if(declArraySize!=null && declArraySize!=rangeExpr.size())
-                            errors.err("range expression size doesn't match declared array size", decl.value?.position!!)
-                        val constRange = rangeExpr.toConstantIntegerRange()
-                        if(constRange!=null) {
-                            val newValue = ArrayLiteralValue(InferredTypes.InferredType.known(DataType.ARRAY_F),
-                                        constRange.map { NumericLiteralValue(DataType.FLOAT, it.toDouble(), decl.value!!.position) }.toTypedArray(),
-                                        position = decl.value!!.position)
-                            return listOf(IAstModification.ReplaceNode(decl.value!!, newValue, decl))
-                        }
-                    }
-                    if(rangeExpr==null && litval!=null) {
-                        // arraysize initializer is a single int, and we know the size.
-                        val fillvalue = litval.number.toDouble()
-                        if (fillvalue < CompilationTarget.machine.FLOAT_MAX_NEGATIVE || fillvalue > CompilationTarget.machine.FLOAT_MAX_POSITIVE)
-                            errors.err("float value overflow", litval.position)
-                        else {
-                            // create the array itself, filled with the fillvalue.
-                            val array = Array(size) {fillvalue}.map { NumericLiteralValue(DataType.FLOAT, it, litval.position) as Expression}.toTypedArray()
-                            val refValue = ArrayLiteralValue(InferredTypes.InferredType.known(DataType.ARRAY_F), array, position = litval.position)
-                            return listOf(IAstModification.ReplaceNode(decl.value!!, refValue, decl))
-                        }
-                    }
-                }
-                else -> {
-                    // nothing to do for this type
-                    // this includes strings and structs
-                }
-            }
-        }
-
-        val declValue = decl.value
-        if(declValue!=null && decl.type==VarDeclType.VAR
-                && declValue is NumericLiteralValue && !declValue.inferType(program).istype(decl.datatype)) {
-            // cast the numeric literal to the appropriate datatype of the variable
-            return listOf(IAstModification.ReplaceNode(decl.value!!, declValue.cast(decl.datatype), decl))
-        }
-
-        return noModifications
-    }
-}
-
-
-internal class ConstantFoldingOptimizer(private val program: Program, private val errors: ErrorReporter) : AstWalker() {
-    private val noModifications = emptyList<IAstModification>()
+class ConstantFoldingOptimizer(private val program: Program) : AstWalker() {
 
     override fun before(memread: DirectMemoryRead, parent: Node): Iterable<IAstModification> {
         // @( &thing )  -->  thing
@@ -191,39 +23,61 @@ internal class ConstantFoldingOptimizer(private val program: Program, private va
             noModifications
     }
 
+    override fun after(containment: ContainmentCheck, parent: Node): Iterable<IAstModification> {
+        val result = containment.constValue(program)
+        if(result!=null)
+            return listOf(IAstModification.ReplaceNode(containment, result, parent))
+        return noModifications
+    }
+
     override fun after(expr: PrefixExpression, parent: Node): Iterable<IAstModification> {
         // Try to turn a unary prefix expression into a single constant value.
         // Compile-time constant sub expressions will be evaluated on the spot.
         // For instance, the expression for "- 4.5" will be optimized into the float literal -4.5
         val subexpr = expr.expression
-        if (subexpr is NumericLiteralValue) {
+        if (subexpr is NumericLiteral) {
             // accept prefixed literal values (such as -3, not true)
             return when (expr.operator) {
                 "+" -> listOf(IAstModification.ReplaceNode(expr, subexpr, parent))
                 "-" -> when (subexpr.type) {
                     in IntegerDatatypes -> {
                         listOf(IAstModification.ReplaceNode(expr,
-                                NumericLiteralValue.optimalNumeric(-subexpr.number.toInt(), subexpr.position),
+                                NumericLiteral.optimalInteger(-subexpr.number.toInt(), subexpr.position),
                                 parent))
                     }
                     DataType.FLOAT -> {
                         listOf(IAstModification.ReplaceNode(expr,
-                                NumericLiteralValue(DataType.FLOAT, -subexpr.number.toDouble(), subexpr.position),
+                                NumericLiteral(DataType.FLOAT, -subexpr.number, subexpr.position),
                                 parent))
                     }
                     else -> throw ExpressionError("can only take negative of int or float", subexpr.position)
                 }
                 "~" -> when (subexpr.type) {
-                    in IntegerDatatypes -> {
+                    DataType.BYTE -> {
                         listOf(IAstModification.ReplaceNode(expr,
-                                NumericLiteralValue.optimalNumeric(subexpr.number.toInt().inv(), subexpr.position),
+                                NumericLiteral(DataType.BYTE, subexpr.number.toInt().inv().toDouble(), subexpr.position),
+                                parent))
+                    }
+                    DataType.UBYTE -> {
+                        listOf(IAstModification.ReplaceNode(expr,
+                                NumericLiteral(DataType.UBYTE, (subexpr.number.toInt().inv() and 255).toDouble(), subexpr.position),
+                                parent))
+                    }
+                    DataType.WORD -> {
+                        listOf(IAstModification.ReplaceNode(expr,
+                                NumericLiteral(DataType.WORD, subexpr.number.toInt().inv().toDouble(), subexpr.position),
+                                parent))
+                    }
+                    DataType.UWORD -> {
+                        listOf(IAstModification.ReplaceNode(expr,
+                                NumericLiteral(DataType.UWORD, (subexpr.number.toInt().inv() and 65535).toDouble(), subexpr.position),
                                 parent))
                     }
                     else -> throw ExpressionError("can only take bitwise inversion of int", subexpr.position)
                 }
                 "not" -> {
                     listOf(IAstModification.ReplaceNode(expr,
-                            NumericLiteralValue.fromBoolean(subexpr.number.toDouble() == 0.0, subexpr.position),
+                            NumericLiteral.fromBoolean(subexpr.number == 0.0, subexpr.position),
                             parent))
                 }
                 else -> throw ExpressionError(expr.operator, subexpr.position)
@@ -232,7 +86,7 @@ internal class ConstantFoldingOptimizer(private val program: Program, private va
         return noModifications
     }
 
-    /**
+    /*
      * Try to constfold a binary expression.
      * Compile-time constant sub expressions will be evaluated on the spot.
      * For instance, "9 * (4 + 2)" will be optimized into the integer literal 54.
@@ -252,38 +106,185 @@ internal class ConstantFoldingOptimizer(private val program: Program, private va
     override fun after(expr: BinaryExpression, parent: Node): Iterable<IAstModification> {
         val leftconst = expr.left.constValue(program)
         val rightconst = expr.right.constValue(program)
+        val modifications = mutableListOf<IAstModification>()
 
-        val subExpr: BinaryExpression? = when {
-            leftconst!=null -> expr.right as? BinaryExpression
-            rightconst!=null -> expr.left as? BinaryExpression
-            else -> null
-        }
-        if(subExpr!=null) {
-            val subleftconst = subExpr.left.constValue(program)
-            val subrightconst = subExpr.right.constValue(program)
-            if ((subleftconst != null && subrightconst == null) || (subleftconst==null && subrightconst!=null)) {
-                // try reordering.
-                val change = groupTwoConstsTogether(expr, subExpr,
-                        leftconst != null, rightconst != null,
-                        subleftconst != null, subrightconst != null)
-                return change?.let { listOf(it) } ?: noModifications
+        if(expr.operator=="==" && rightconst!=null) {
+            val leftExpr = expr.left as? BinaryExpression
+            if(leftExpr!=null) {
+                val leftRightConst = leftExpr.right.constValue(program)
+                if(leftRightConst!=null) {
+                    when (leftExpr.operator) {
+                        "+" -> {
+                            // X + С1 == C2  -->  X == C2 - C1
+                            val newRightConst = NumericLiteral(rightconst.type, rightconst.number - leftRightConst.number, rightconst.position)
+                            return listOf(
+                                IAstModification.ReplaceNode(leftExpr, leftExpr.left, expr),
+                                IAstModification.ReplaceNode(expr.right, newRightConst, expr)
+                            )
+                        }
+                        "-" -> {
+                            // X - С1 == C2  -->  X == C2 + C1
+                            val newRightConst = NumericLiteral(rightconst.type, rightconst.number + leftRightConst.number, rightconst.position)
+                            return listOf(
+                                IAstModification.ReplaceNode(leftExpr, leftExpr.left, expr),
+                                IAstModification.ReplaceNode(expr.right, newRightConst, expr)
+                            )
+                        }
+                    }
+                }
             }
         }
 
-        // const fold when both operands are a const
-        if(leftconst != null && rightconst != null) {
-            val evaluator = ConstExprEvaluator()
-            return listOf(IAstModification.ReplaceNode(
-                    expr,
-                    evaluator.evaluate(leftconst, expr.operator, rightconst),
-                    parent
-            ))
+        if(expr.operator == "**" && leftconst!=null) {
+            // optimize various simple cases of ** :
+            //  optimize away 1 ** x into just 1 and 0 ** x into just 0
+            //  optimize 2 ** x into (1<<x)  if both operands are integer.
+            val leftDt = leftconst.inferType(program).getOr(DataType.UNDEFINED)
+            when (leftconst.number) {
+                0.0 -> {
+                    val value = NumericLiteral(leftDt, 0.0, expr.position)
+                    modifications += IAstModification.ReplaceNode(expr, value, parent)
+                }
+                1.0 -> {
+                    val value = NumericLiteral(leftDt, 1.0, expr.position)
+                    modifications += IAstModification.ReplaceNode(expr, value, parent)
+                }
+                2.0 -> {
+                    if(rightconst!=null) {
+                        val value = NumericLiteral(leftDt, 2.0.pow(rightconst.number), expr.position)
+                        modifications += IAstModification.ReplaceNode(expr, value, parent)
+                    } else {
+                        val rightDt = expr.right.inferType(program).getOr(DataType.UNDEFINED)
+                        if(leftDt in IntegerDatatypes && rightDt in IntegerDatatypes) {
+                            val targetDt =
+                                when (parent) {
+                                    is Assignment -> parent.target.inferType(program).getOr(DataType.UNDEFINED)
+                                    is VarDecl -> parent.datatype
+                                    else -> leftDt
+                                }
+                            val one = NumericLiteral(targetDt, 1.0, expr.position)
+                            val shift = BinaryExpression(one, "<<", expr.right, expr.position)
+                            modifications += IAstModification.ReplaceNode(expr, shift, parent)
+                        }
+                    }
+                }
+            }
         }
 
-        return noModifications
+        if(expr.inferType(program) istype DataType.FLOAT) {
+            val subExpr: BinaryExpression? = when {
+                leftconst != null -> expr.right as? BinaryExpression
+                rightconst != null -> expr.left as? BinaryExpression
+                else -> null
+            }
+            if (subExpr != null) {
+                val subleftconst = subExpr.left.constValue(program)
+                val subrightconst = subExpr.right.constValue(program)
+                if ((subleftconst != null && subrightconst == null) || (subleftconst == null && subrightconst != null)) {
+                    // try reordering.
+                    val change = groupTwoFloatConstsTogether(
+                        expr, subExpr,
+                        leftconst != null, rightconst != null,
+                        subleftconst != null, subrightconst != null
+                    )
+                    if (change != null)
+                        modifications += change
+                }
+            }
+        }
+
+        val evaluator = ConstExprEvaluator()
+
+        // const fold when both operands are a const
+        if(leftconst != null && rightconst != null) {
+            val result = evaluator.evaluate(leftconst, expr.operator, rightconst)
+            modifications += IAstModification.ReplaceNode(expr, result, parent)
+        }
+
+
+        val leftBinExpr = expr.left as? BinaryExpression
+        val rightBinExpr = expr.right as? BinaryExpression
+
+        if(leftBinExpr!=null && rightconst!=null) {
+            if(expr.operator=="+" || expr.operator=="-") {
+                if(leftBinExpr.operator in listOf("+", "-")) {
+                    val c2 = leftBinExpr.right.constValue(program)
+                    if(c2!=null) {
+                        // (X + C2) +/- rightConst  -->  X + (C2 +/- rightConst)
+                        // (X - C2) +/- rightConst  -->  X - (C2 +/- rightConst)   mind the flipped right operator
+                        val operator = if(leftBinExpr.operator=="+") expr.operator else if(expr.operator=="-") "+" else "-"
+                        val constants = BinaryExpression(c2, operator, rightconst, c2.position)
+                        val newExpr = BinaryExpression(leftBinExpr.left, leftBinExpr.operator, constants, expr.position)
+                        return listOf(IAstModification.ReplaceNode(expr, newExpr, parent))
+                    }
+                }
+            }
+            else if(expr.operator=="*") {
+                val c2 = leftBinExpr.right.constValue(program)
+                if(c2!=null) {
+                    if(leftBinExpr.operator=="*") {
+                        // (X * C2) * rightConst  -->  X * (rightConst*C2)
+                        val constants = BinaryExpression(rightconst, "*", c2, c2.position)
+                        val newExpr = BinaryExpression(leftBinExpr.left, "*", constants, expr.position)
+                        return listOf(IAstModification.ReplaceNode(expr, newExpr, parent))
+                    } else if (leftBinExpr.operator=="/") {
+                        //  (X / C2) * rightConst   -->  X * (rightConst/C2)
+                        val constants = BinaryExpression(rightconst, "/", c2, c2.position)
+                        val newExpr = BinaryExpression(leftBinExpr.left, "*", constants, expr.position)
+                        return listOf(IAstModification.ReplaceNode(expr, newExpr, parent))
+                    }
+                }
+            }
+            else if(expr.operator=="/") {
+                val c2 = leftBinExpr.right.constValue(program)
+                if(c2!=null && leftBinExpr.operator=="/") {
+                    // (X / C1) / C2   -->  X / (C1*C2)
+                    // NOTE: do not optimize  (X * C1) / C2   -->  X * (C1/C2)  because this causes precision loss on integers
+                    val constants = BinaryExpression(c2, "*", rightconst, c2.position)
+                    val newExpr = BinaryExpression(leftBinExpr.left, "/", constants, expr.position)
+                    return listOf(IAstModification.ReplaceNode(expr, newExpr, parent))
+                }
+            }
+        }
+
+        if(expr.operator=="+" || expr.operator=="-") {
+            if(leftBinExpr!=null && rightBinExpr!=null) {
+                val c1 = leftBinExpr.right.constValue(program)
+                val c2 = rightBinExpr.right.constValue(program)
+                if(leftBinExpr.operator=="+" && rightBinExpr.operator=="+") {
+                    if (c1 != null && c2 != null) {
+                        // (X + C1) <plusmin> (Y + C2)  =>  (X <plusmin> Y) + (C1 <plusmin> C2)
+                        val c3 = evaluator.evaluate(c1, expr.operator, c2)
+                        val xwithy = BinaryExpression(leftBinExpr.left, expr.operator, rightBinExpr.left, expr.position)
+                        val newExpr = BinaryExpression(xwithy, "+", c3, expr.position)
+                        modifications += IAstModification.ReplaceNode(expr, newExpr, parent)
+                    }
+                }
+                else if(leftBinExpr.operator=="-" && rightBinExpr.operator=="-") {
+                    if (c1 != null && c2 != null) {
+                        // (X - C1) <plusmin> (Y - C2)  =>  (X <plusmin> Y) - (C1 <plusmin> C2)
+                        val c3 = evaluator.evaluate(c1, expr.operator, c2)
+                        val xwithy = BinaryExpression(leftBinExpr.left, expr.operator, rightBinExpr.left, expr.position)
+                        val newExpr = BinaryExpression(xwithy, "-", c3, expr.position)
+                        modifications += IAstModification.ReplaceNode(expr, newExpr, parent)
+                    }
+                }
+                else if(leftBinExpr.operator=="*" && rightBinExpr.operator=="*"){
+                    if (c1 != null && c2 != null && c1==c2) {
+                        //(X * C) <plusmin> (Y * C)  =>  (X <plusmin> Y) * C
+                        val xwithy = BinaryExpression(leftBinExpr.left, expr.operator, rightBinExpr.left, expr.position)
+                        val newExpr = BinaryExpression(xwithy, "*", c1, expr.position)
+                        modifications += IAstModification.ReplaceNode(expr, newExpr, parent)
+                    }
+                }
+            }
+        }
+
+
+        return modifications
     }
 
-    override fun after(array: ArrayLiteralValue, parent: Node): Iterable<IAstModification> {
+    override fun after(array: ArrayLiteral, parent: Node): Iterable<IAstModification> {
         // because constant folding can result in arrays that are now suddenly capable
         // of telling the type of all their elements (for instance, when they contained -2 which
         // was a prefix expression earlier), we recalculate the array's datatype.
@@ -300,7 +301,7 @@ internal class ConstantFoldingOptimizer(private val program: Program, private va
         } else {
             val arrayDt = array.guessDatatype(program)
             if (arrayDt.isKnown) {
-                val newArray = array.cast(arrayDt.typeOrElse(DataType.STRUCT))
+                val newArray = array.cast(arrayDt.getOr(DataType.UNDEFINED))
                 if (newArray != null && newArray != array)
                     return listOf(IAstModification.ReplaceNode(array, newArray, parent))
             }
@@ -309,78 +310,97 @@ internal class ConstantFoldingOptimizer(private val program: Program, private va
         return noModifications
     }
 
-    override fun after(functionCall: FunctionCall, parent: Node): Iterable<IAstModification> {
+    override fun after(functionCallExpr: FunctionCallExpression, parent: Node): Iterable<IAstModification> {
         // the args of a fuction are constfolded via recursion already.
-        val constvalue = functionCall.constValue(program)
+        val constvalue = functionCallExpr.constValue(program)
         return if(constvalue!=null)
-            listOf(IAstModification.ReplaceNode(functionCall, constvalue, parent))
+            listOf(IAstModification.ReplaceNode(functionCallExpr, constvalue, parent))
         else
             noModifications
     }
 
     override fun after(forLoop: ForLoop, parent: Node): Iterable<IAstModification> {
-        fun adjustRangeDt(rangeFrom: NumericLiteralValue, targetDt: DataType, rangeTo: NumericLiteralValue, stepLiteral: NumericLiteralValue?, range: RangeExpr): RangeExpr {
-            val newFrom: NumericLiteralValue
-            val newTo: NumericLiteralValue
-            try {
-                newFrom = rangeFrom.cast(targetDt)
-                newTo = rangeTo.cast(targetDt)
-            } catch (x: ExpressionError) {
-                return range
-            }
-            val newStep: Expression = try {
-                stepLiteral?.cast(targetDt)?: range.step
-            } catch(ee: ExpressionError) {
-                range.step
-            }
-            return RangeExpr(newFrom, newTo, newStep, range.position)
+        fun adjustRangeDt(rangeFrom: NumericLiteral, targetDt: DataType, rangeTo: NumericLiteral, stepLiteral: NumericLiteral?, range: RangeExpression): RangeExpression? {
+            val fromCast = rangeFrom.cast(targetDt)
+            val toCast = rangeTo.cast(targetDt)
+            if(!fromCast.isValid || !toCast.isValid)
+                return null
+
+            val newStep =
+                if(stepLiteral!=null) {
+                    val stepCast = stepLiteral.cast(targetDt)
+                    if(stepCast.isValid)
+                        stepCast.valueOrZero()
+                    else
+                        range.step
+                } else {
+                    range.step
+                }
+
+            return RangeExpression(fromCast.valueOrZero(), toCast.valueOrZero(), newStep, range.position)
         }
 
         // adjust the datatype of a range expression in for loops to the loop variable.
-        val iterableRange = forLoop.iterable as? RangeExpr ?: return noModifications
-        val rangeFrom = iterableRange.from as? NumericLiteralValue
-        val rangeTo = iterableRange.to as? NumericLiteralValue
+        val iterableRange = forLoop.iterable as? RangeExpression ?: return noModifications
+        val rangeFrom = iterableRange.from as? NumericLiteral
+        val rangeTo = iterableRange.to as? NumericLiteral
         if(rangeFrom==null || rangeTo==null) return noModifications
 
-        val loopvar = forLoop.loopVar?.targetVarDecl(program.namespace)
-        if(loopvar!=null) {
-            val stepLiteral = iterableRange.step as? NumericLiteralValue
-            when(loopvar.datatype) {
-                DataType.UBYTE -> {
-                    if(rangeFrom.type!= DataType.UBYTE) {
-                        // attempt to translate the iterable into ubyte values
-                        val newIter = adjustRangeDt(rangeFrom, loopvar.datatype, rangeTo, stepLiteral, iterableRange)
+        val loopvar = forLoop.loopVar.targetVarDecl(program) ?: throw UndefinedSymbolError(forLoop.loopVar)
+
+        val stepLiteral = iterableRange.step as? NumericLiteral
+        when(loopvar.datatype) {
+            DataType.UBYTE -> {
+                if(rangeFrom.type!= DataType.UBYTE) {
+                    // attempt to translate the iterable into ubyte values
+                    val newIter = adjustRangeDt(rangeFrom, loopvar.datatype, rangeTo, stepLiteral, iterableRange)
+                    if(newIter!=null)
                         return listOf(IAstModification.ReplaceNode(forLoop.iterable, newIter, forLoop))
-                    }
                 }
-                DataType.BYTE -> {
-                    if(rangeFrom.type!= DataType.BYTE) {
-                        // attempt to translate the iterable into byte values
-                        val newIter = adjustRangeDt(rangeFrom, loopvar.datatype, rangeTo, stepLiteral, iterableRange)
-                        return listOf(IAstModification.ReplaceNode(forLoop.iterable, newIter, forLoop))
-                    }
-                }
-                DataType.UWORD -> {
-                    if(rangeFrom.type!= DataType.UWORD) {
-                        // attempt to translate the iterable into uword values
-                        val newIter = adjustRangeDt(rangeFrom, loopvar.datatype, rangeTo, stepLiteral, iterableRange)
-                        return listOf(IAstModification.ReplaceNode(forLoop.iterable, newIter, forLoop))
-                    }
-                }
-                DataType.WORD -> {
-                    if(rangeFrom.type!= DataType.WORD) {
-                        // attempt to translate the iterable into word values
-                        val newIter = adjustRangeDt(rangeFrom, loopvar.datatype, rangeTo, stepLiteral, iterableRange)
-                        return listOf(IAstModification.ReplaceNode(forLoop.iterable, newIter, forLoop))
-                    }
-                }
-                else -> throw FatalAstException("invalid loopvar datatype $loopvar")
             }
+            DataType.BYTE -> {
+                if(rangeFrom.type!= DataType.BYTE) {
+                    // attempt to translate the iterable into byte values
+                    val newIter = adjustRangeDt(rangeFrom, loopvar.datatype, rangeTo, stepLiteral, iterableRange)
+                    if(newIter!=null)
+                        return listOf(IAstModification.ReplaceNode(forLoop.iterable, newIter, forLoop))
+                }
+            }
+            DataType.UWORD -> {
+                if(rangeFrom.type!= DataType.UWORD) {
+                    // attempt to translate the iterable into uword values
+                    val newIter = adjustRangeDt(rangeFrom, loopvar.datatype, rangeTo, stepLiteral, iterableRange)
+                    if(newIter!=null)
+                        return listOf(IAstModification.ReplaceNode(forLoop.iterable, newIter, forLoop))
+                }
+            }
+            DataType.WORD -> {
+                if(rangeFrom.type!= DataType.WORD) {
+                    // attempt to translate the iterable into word values
+                    val newIter = adjustRangeDt(rangeFrom, loopvar.datatype, rangeTo, stepLiteral, iterableRange)
+                    if(newIter!=null)
+                        return listOf(IAstModification.ReplaceNode(forLoop.iterable, newIter, forLoop))
+                }
+            }
+            else -> throw FatalAstException("invalid loopvar datatype $loopvar")
         }
 
         return noModifications
     }
 
+    override fun after(decl: VarDecl, parent: Node): Iterable<IAstModification> {
+        val numval = decl.value as? NumericLiteral
+        if(decl.type== VarDeclType.CONST && numval!=null) {
+            val valueDt = numval.inferType(program)
+            if(valueDt isnot decl.datatype) {
+                val cast = numval.cast(decl.datatype)
+                if(cast.isValid)
+                    return listOf(IAstModification.ReplaceNode(numval, cast.valueOrZero(), decl))
+            }
+        }
+        return noModifications
+    }
+
     private class ShuffleOperands(val expr: BinaryExpression,
                                   val exprOperator: String?,
                                   val subExpr: BinaryExpression,
@@ -398,18 +418,21 @@ internal class ConstantFoldingOptimizer(private val program: Program, private va
         }
     }
 
-    private fun groupTwoConstsTogether(expr: BinaryExpression,
-                                       subExpr: BinaryExpression,
-                                       leftIsConst: Boolean,
-                                       rightIsConst: Boolean,
-                                       subleftIsConst: Boolean,
-                                       subrightIsConst: Boolean): IAstModification?
+    private fun groupTwoFloatConstsTogether(expr: BinaryExpression,
+       subExpr: BinaryExpression,
+       leftIsConst: Boolean,
+       rightIsConst: Boolean,
+       subleftIsConst: Boolean,
+       subrightIsConst: Boolean): IAstModification?
     {
-        // todo: this implements only a small set of possible reorderings at this time
+        // NOTE: THIS IS ONLY VALID ON FLOATING POINT CONSTANTS
+
+        // TODO: this implements only a small set of possible reorderings at this time, we could think of more
         if(expr.operator==subExpr.operator) {
             // both operators are the same.
-            // If + or *,  we can simply shuffle the const operands around to optimize.
-            if(expr.operator=="+" || expr.operator=="*") {
+
+            // If associative,  we can simply shuffle the const operands around to optimize.
+            if(expr.operator in AssociativeOperators) {
                 return if(leftIsConst) {
                     if(subleftIsConst)
                         ShuffleOperands(expr, null, subExpr, subExpr.right, null, null, expr.left)

codeOptimizers/src/prog8/optimizer/ConstantIdentifierReplacer.kt

@@ -0,0 +1,235 @@
+package prog8.optimizer
+
+import prog8.ast.Node
+import prog8.ast.Program
+import prog8.ast.base.*
+import prog8.ast.expressions.*
+import prog8.ast.statements.*
+import prog8.ast.walk.AstWalker
+import prog8.ast.walk.IAstModification
+import prog8.compilerinterface.ICompilationTarget
+import prog8.compilerinterface.IErrorReporter
+import prog8.compilerinterface.InternalCompilerException
+
+// Fix up the literal value's type to match that of the vardecl
+//   (also check range literal operands types before they get expanded into arrays for instance)
+class VarConstantValueTypeAdjuster(private val program: Program, private val errors: IErrorReporter) : AstWalker() {
+
+    override fun after(decl: VarDecl, parent: Node): Iterable<IAstModification> {
+
+        if(decl.parent is AnonymousScope)
+            throw FatalAstException("vardecl may no longer occur in anonymousscope")
+
+        try {
+            val declConstValue = decl.value?.constValue(program)
+            if(declConstValue!=null && (decl.type==VarDeclType.VAR || decl.type==VarDeclType.CONST)
+                && declConstValue.type != decl.datatype) {
+                // avoid silent float roundings
+                if(decl.datatype in IntegerDatatypes && declConstValue.type==DataType.FLOAT) {
+                    errors.err("refused rounding of float to avoid loss of precision", decl.value!!.position)
+                } else {
+                    // cast the numeric literal to the appropriate datatype of the variable
+                    val cast = declConstValue.cast(decl.datatype)
+                    if (cast.isValid)
+                        return listOf(IAstModification.ReplaceNode(decl.value!!, cast.valueOrZero(), decl))
+                }
+            }
+        } catch (x: UndefinedSymbolError) {
+            errors.err(x.message, x.position)
+        }
+
+        return noModifications
+    }
+
+    override fun after(range: RangeExpression, parent: Node): Iterable<IAstModification> {
+        val from = range.from.constValue(program)?.number
+        val to = range.to.constValue(program)?.number
+        val step = range.step.constValue(program)?.number
+
+        if(from==null) {
+            if(!range.from.inferType(program).isInteger)
+                errors.err("range expression from value must be integer", range.from.position)
+        } else if(from-from.toInt()>0) {
+            errors.err("range expression from value must be integer", range.from.position)
+        }
+
+        if(to==null) {
+            if(!range.to.inferType(program).isInteger)
+                errors.err("range expression to value must be integer", range.to.position)
+        } else if(to-to.toInt()>0) {
+            errors.err("range expression to value must be integer", range.to.position)
+        }
+
+        if(step==null) {
+            if(!range.step.inferType(program).isInteger)
+                errors.err("range expression step value must be integer", range.step.position)
+        } else if(step-step.toInt()>0) {
+            errors.err("range expression step value must be integer", range.step.position)
+        }
+
+        return noModifications
+    }
+}
+
+
+// Replace all constant identifiers with their actual value,
+// and the array var initializer values and sizes.
+// This is needed because further constant optimizations depend on those.
+internal class ConstantIdentifierReplacer(private val program: Program, private val errors: IErrorReporter, private val compTarget: ICompilationTarget) : AstWalker() {
+
+    override fun after(identifier: IdentifierReference, parent: Node): Iterable<IAstModification> {
+        // replace identifiers that refer to const value, with the value itself
+        // if it's a simple type and if it's not a left hand side variable
+        if(identifier.parent is AssignTarget)
+            return noModifications
+        var forloop = identifier.parent as? ForLoop
+        if(forloop==null)
+            forloop = identifier.parent.parent as? ForLoop
+        if(forloop!=null && identifier===forloop.loopVar)
+            return noModifications
+
+        try {
+            val cval = identifier.constValue(program) ?: return noModifications
+            return when (cval.type) {
+                in NumericDatatypes -> listOf(
+                    IAstModification.ReplaceNode(
+                        identifier,
+                        NumericLiteral(cval.type, cval.number, identifier.position),
+                        identifier.parent
+                    )
+                )
+                in PassByReferenceDatatypes -> throw InternalCompilerException("pass-by-reference type should not be considered a constant")
+                else -> noModifications
+            }
+        } catch (x: UndefinedSymbolError) {
+            errors.err(x.message, x.position)
+            return noModifications
+        }
+    }
+
+    override fun before(decl: VarDecl, parent: Node): Iterable<IAstModification> {
+        // the initializer value can't refer to the variable itself (recursive definition)
+        if(decl.value?.referencesIdentifier(listOf(decl.name)) == true || decl.arraysize?.indexExpr?.referencesIdentifier(listOf(decl.name)) == true) {
+            errors.err("recursive var declaration", decl.position)
+            return noModifications
+        }
+
+        if(decl.type== VarDeclType.CONST || decl.type== VarDeclType.VAR) {
+            if(decl.isArray){
+                val arraysize = decl.arraysize
+                if(arraysize==null) {
+                    // for arrays that have no size specifier attempt to deduce the size
+                    val arrayval = decl.value as? ArrayLiteral
+                    if(arrayval!=null) {
+                        return listOf(IAstModification.SetExpression(
+                                { decl.arraysize = ArrayIndex(it, decl.position) },
+                                NumericLiteral.optimalInteger(arrayval.value.size, decl.position),
+                                decl
+                        ))
+                    }
+                }
+            }
+
+            when(decl.datatype) {
+                DataType.FLOAT -> {
+                    // vardecl: for scalar float vars, promote constant integer initialization values to floats
+                    val litval = decl.value as? NumericLiteral
+                    if (litval!=null && litval.type in IntegerDatatypes) {
+                        val newValue = NumericLiteral(DataType.FLOAT, litval.number, litval.position)
+                        return listOf(IAstModification.ReplaceNode(decl.value!!, newValue, decl))
+                    }
+                }
+                DataType.ARRAY_UB, DataType.ARRAY_B, DataType.ARRAY_UW, DataType.ARRAY_W -> {
+                    val rangeExpr = decl.value as? RangeExpression
+                    if(rangeExpr!=null) {
+                        // convert the initializer range expression to an actual array
+                        val declArraySize = decl.arraysize?.constIndex()
+                        if(declArraySize!=null && declArraySize!=rangeExpr.size())
+                            errors.err("range expression size (${rangeExpr.size()}) doesn't match declared array size ($declArraySize)", decl.value?.position!!)
+                        val constRange = rangeExpr.toConstantIntegerRange()
+                        if(constRange!=null) {
+                            val eltType = rangeExpr.inferType(program).getOr(DataType.UBYTE)
+                            val newValue = if(eltType in ByteDatatypes) {
+                                ArrayLiteral(InferredTypes.InferredType.known(decl.datatype),
+                                        constRange.map { NumericLiteral(eltType, it.toDouble(), decl.value!!.position) }.toTypedArray(),
+                                        position = decl.value!!.position)
+                            } else {
+                                ArrayLiteral(InferredTypes.InferredType.known(decl.datatype),
+                                        constRange.map { NumericLiteral(eltType, it.toDouble(), decl.value!!.position) }.toTypedArray(),
+                                        position = decl.value!!.position)
+                            }
+                            return listOf(IAstModification.ReplaceNode(decl.value!!, newValue, decl))
+                        }
+                    }
+                    val numericLv = decl.value as? NumericLiteral
+                    if(numericLv!=null && numericLv.type== DataType.FLOAT)
+                        errors.err("arraysize requires only integers here", numericLv.position)
+                    val size = decl.arraysize?.constIndex() ?: return noModifications
+                    if (rangeExpr==null && numericLv!=null) {
+                        // arraysize initializer is empty or a single int, and we know the size; create the arraysize.
+                        val fillvalue = numericLv.number.toInt()
+                        when(decl.datatype){
+                            DataType.ARRAY_UB -> {
+                                if(fillvalue !in 0..255)
+                                    errors.err("ubyte value overflow", numericLv.position)
+                            }
+                            DataType.ARRAY_B -> {
+                                if(fillvalue !in -128..127)
+                                    errors.err("byte value overflow", numericLv.position)
+                            }
+                            DataType.ARRAY_UW -> {
+                                if(fillvalue !in 0..65535)
+                                    errors.err("uword value overflow", numericLv.position)
+                            }
+                            DataType.ARRAY_W -> {
+                                if(fillvalue !in -32768..32767)
+                                    errors.err("word value overflow", numericLv.position)
+                            }
+                            else -> {}
+                        }
+                        // create the array itself, filled with the fillvalue.
+                        val array = Array(size) {fillvalue}.map { NumericLiteral(ArrayToElementTypes.getValue(decl.datatype), it.toDouble(), numericLv.position) }.toTypedArray<Expression>()
+                        val refValue = ArrayLiteral(InferredTypes.InferredType.known(decl.datatype), array, position = numericLv.position)
+                        return listOf(IAstModification.ReplaceNode(decl.value!!, refValue, decl))
+                    }
+                }
+                DataType.ARRAY_F -> {
+                    val rangeExpr = decl.value as? RangeExpression
+                    if(rangeExpr!=null) {
+                        // convert the initializer range expression to an actual array of floats
+                        val declArraySize = decl.arraysize?.constIndex()
+                        if(declArraySize!=null && declArraySize!=rangeExpr.size())
+                            errors.err("range expression size (${rangeExpr.size()}) doesn't match declared array size ($declArraySize)", decl.value?.position!!)
+                        val constRange = rangeExpr.toConstantIntegerRange()
+                        if(constRange!=null) {
+                            val newValue = ArrayLiteral(InferredTypes.InferredType.known(DataType.ARRAY_F),
+                                    constRange.map { NumericLiteral(DataType.FLOAT, it.toDouble(), decl.value!!.position) }.toTypedArray(),
+                                    position = decl.value!!.position)
+                            return listOf(IAstModification.ReplaceNode(decl.value!!, newValue, decl))
+                        }
+                    }
+
+                    val numericLv = decl.value as? NumericLiteral
+                    val size = decl.arraysize?.constIndex() ?: return noModifications
+                    if(rangeExpr==null && numericLv!=null) {
+                        // arraysize initializer is a single int, and we know the size.
+                        val fillvalue = numericLv.number
+                        if (fillvalue < compTarget.machine.FLOAT_MAX_NEGATIVE || fillvalue > compTarget.machine.FLOAT_MAX_POSITIVE)
+                            errors.err("float value overflow", numericLv.position)
+                        else {
+                            // create the array itself, filled with the fillvalue.
+                            val array = Array(size) {fillvalue}.map { NumericLiteral(DataType.FLOAT, it, numericLv.position) }.toTypedArray<Expression>()
+                            val refValue = ArrayLiteral(InferredTypes.InferredType.known(DataType.ARRAY_F), array, position = numericLv.position)
+                            return listOf(IAstModification.ReplaceNode(decl.value!!, refValue, decl))
+                        }
+                    }
+                }
+                else -> {
+                    // nothing to do for this type
+                }
+            }
+        }
+
+        return noModifications
+    }
+}

codeOptimizers/src/prog8/optimizer/ExpressionSimplifier.kt

@@ -0,0 +1,730 @@
+package prog8.optimizer
+
+import prog8.ast.*
+import prog8.ast.base.DataType
+import prog8.ast.base.FatalAstException
+import prog8.ast.base.IntegerDatatypes
+import prog8.ast.base.NumericDatatypes
+import prog8.ast.expressions.*
+import prog8.ast.statements.*
+import prog8.ast.walk.AstWalker
+import prog8.ast.walk.IAstModification
+import prog8.compilerinterface.IErrorReporter
+import kotlin.math.abs
+import kotlin.math.log2
+import kotlin.math.pow
+
+// TODO add more peephole expression optimizations? Investigate what optimizations binaryen has, also see  https://egorbo.com/peephole-optimizations.html
+
+class ExpressionSimplifier(private val program: Program, private val errors: IErrorReporter) : AstWalker() {
+    private val powersOfTwo = (1..16).map { (2.0).pow(it) }.toSet()
+    private val negativePowersOfTwo = powersOfTwo.map { -it }.toSet()
+
+    override fun after(typecast: TypecastExpression, parent: Node): Iterable<IAstModification> {
+        val mods = mutableListOf<IAstModification>()
+
+        // try to statically convert a literal value into one of the desired type
+        val literal = typecast.expression as? NumericLiteral
+        if (literal != null) {
+            val newLiteral = literal.cast(typecast.type)
+            if (newLiteral.isValid && newLiteral.valueOrZero() !== literal)
+                mods += IAstModification.ReplaceNode(typecast.expression, newLiteral.valueOrZero(), typecast)
+        }
+
+        // remove redundant nested typecasts
+        val subTypecast = typecast.expression as? TypecastExpression
+        if (subTypecast != null) {
+            // remove the sub-typecast if its datatype is larger than the outer typecast
+            if(subTypecast.type largerThan typecast.type) {
+                mods += IAstModification.ReplaceNode(typecast.expression, subTypecast.expression, typecast)
+            }
+        } else {
+            if (typecast.expression.inferType(program) istype typecast.type) {
+                // remove duplicate cast
+                mods += IAstModification.ReplaceNode(typecast, typecast.expression, parent)
+            }
+        }
+
+        return mods
+    }
+
+    override fun after(ifElse: IfElse, parent: Node): Iterable<IAstModification> {
+        val truepart = ifElse.truepart
+        val elsepart = ifElse.elsepart
+        if(truepart.isNotEmpty() && elsepart.isNotEmpty()) {
+            if(truepart.statements.singleOrNull() is Jump) {
+                return listOf(
+                    IAstModification.InsertAfter(ifElse, elsepart, parent as IStatementContainer),
+                    IAstModification.ReplaceNode(elsepart, AnonymousScope(mutableListOf(), elsepart.position), ifElse)
+                )
+            }
+            if(elsepart.statements.singleOrNull() is Jump) {
+                val invertedCondition = invertCondition(ifElse.condition)
+                if(invertedCondition!=null) {
+                    return listOf(
+                        IAstModification.ReplaceNode(ifElse.condition, invertedCondition, ifElse),
+                        IAstModification.InsertAfter(ifElse, truepart, parent as IStatementContainer),
+                        IAstModification.ReplaceNode(elsepart, AnonymousScope(mutableListOf(), elsepart.position), ifElse),
+                        IAstModification.ReplaceNode(truepart, elsepart, ifElse)
+                    )
+                }
+            }
+        }
+        return noModifications
+    }
+
+    override fun after(expr: BinaryExpression, parent: Node): Iterable<IAstModification> {
+        val leftVal = expr.left.constValue(program)
+        val rightVal = expr.right.constValue(program)
+
+        val leftIDt = expr.left.inferType(program)
+        val rightIDt = expr.right.inferType(program)
+        if (!leftIDt.isKnown || !rightIDt.isKnown)
+            throw FatalAstException("can't determine datatype of both expression operands $expr")
+
+        // ConstValue <associativeoperator> X -->  X <associativeoperator> ConstValue
+        if (leftVal != null && expr.operator in AssociativeOperators && rightVal == null)
+            return listOf(IAstModification.SwapOperands(expr))
+
+        // NonBinaryExpression  <associativeoperator>  BinaryExpression  -->  BinaryExpression  <associativeoperator>  NonBinaryExpression
+        if (expr.operator in AssociativeOperators && expr.left !is BinaryExpression && expr.right is BinaryExpression) {
+            if(parent !is Assignment || !(expr.left isSameAs parent.target))
+                return listOf(IAstModification.SwapOperands(expr))
+        }
+
+        // X + (-A)  -->  X - A
+        if (expr.operator == "+" && (expr.right as? PrefixExpression)?.operator == "-") {
+            return listOf(IAstModification.ReplaceNode(
+                    expr,
+                    BinaryExpression(expr.left, "-", (expr.right as PrefixExpression).expression, expr.position),
+                    parent
+            ))
+        }
+
+        // (-A) + X  -->  X - A
+        if (expr.operator == "+" && (expr.left as? PrefixExpression)?.operator == "-") {
+            return listOf(IAstModification.ReplaceNode(
+                    expr,
+                    BinaryExpression(expr.right, "-", (expr.left as PrefixExpression).expression, expr.position),
+                    parent
+            ))
+        }
+
+        // X - (-A)  -->  X + A
+        if (expr.operator == "-" && (expr.right as? PrefixExpression)?.operator == "-") {
+            return listOf(IAstModification.ReplaceNode(
+                    expr,
+                    BinaryExpression(expr.left, "+", (expr.right as PrefixExpression).expression, expr.position),
+                    parent
+            ))
+        }
+
+        val leftDt = leftIDt.getOr(DataType.UNDEFINED)
+        val rightDt = rightIDt.getOr(DataType.UNDEFINED)
+
+        if (expr.operator == "+" || expr.operator == "-"
+                && leftVal == null && rightVal == null
+                && leftDt in NumericDatatypes && rightDt in NumericDatatypes) {
+            val leftBinExpr = expr.left as? BinaryExpression
+            val rightBinExpr = expr.right as? BinaryExpression
+            if (leftBinExpr?.operator == "*") {
+                if (expr.operator == "+") {
+                    // Y*X + X  ->  X*(Y + 1)
+                    // X*Y + X  ->  X*(Y + 1)
+                    val x = expr.right
+                    val y = determineY(x, leftBinExpr)
+                    if (y != null) {
+                        val yPlus1 = BinaryExpression(y, "+", NumericLiteral(leftDt, 1.0, y.position), y.position)
+                        val newExpr = BinaryExpression(x, "*", yPlus1, x.position)
+                        return listOf(IAstModification.ReplaceNode(expr, newExpr, parent))
+                    }
+                } else {
+                    // Y*X - X  ->  X*(Y - 1)
+                    // X*Y - X  ->  X*(Y - 1)
+                    val x = expr.right
+                    val y = determineY(x, leftBinExpr)
+                    if (y != null) {
+                        val yMinus1 = BinaryExpression(y, "-", NumericLiteral(leftDt, 1.0, y.position), y.position)
+                        val newExpr = BinaryExpression(x, "*", yMinus1, x.position)
+                        return listOf(IAstModification.ReplaceNode(expr, newExpr, parent))
+                    }
+                }
+            } else if (rightBinExpr?.operator == "*") {
+                if (expr.operator == "+") {
+                    // X + Y*X  ->  X*(Y + 1)
+                    // X + X*Y  ->  X*(Y + 1)
+                    val x = expr.left
+                    val y = determineY(x, rightBinExpr)
+                    if (y != null) {
+                        val yPlus1 = BinaryExpression(y, "+", NumericLiteral.optimalInteger(1, y.position), y.position)
+                        val newExpr = BinaryExpression(x, "*", yPlus1, x.position)
+                        return listOf(IAstModification.ReplaceNode(expr, newExpr, parent))
+                    }
+                }
+            }
+        }
+
+        if(leftDt!=DataType.FLOAT && expr.operator == ">=" && rightVal?.number == 1.0) {
+            // for integers: x >= 1  -->  x > 0
+            expr.operator = ">"
+            return listOf(IAstModification.ReplaceNode(expr.right, NumericLiteral.optimalInteger(0, expr.right.position), expr))
+        }
+
+        if(expr.operator == ">=" && rightVal?.number == 0.0) {
+            if (leftDt == DataType.UBYTE || leftDt == DataType.UWORD) {
+                // unsigned >= 0 --> true
+                return listOf(IAstModification.ReplaceNode(expr, NumericLiteral.fromBoolean(true, expr.position), parent))
+            }
+        }
+
+        if(leftDt!=DataType.FLOAT && expr.operator == "<" && rightVal?.number == 1.0) {
+            // for integers: x < 1  -->  x <= 0
+            expr.operator = "<="
+            return listOf(IAstModification.ReplaceNode(expr.right, NumericLiteral.optimalInteger(0, expr.right.position), expr))
+        }
+
+        if(expr.operator == "<" && rightVal?.number == 0.0) {
+            if (leftDt == DataType.UBYTE || leftDt == DataType.UWORD) {
+                // unsigned < 0 --> false
+                return listOf(IAstModification.ReplaceNode(expr, NumericLiteral.fromBoolean(false, expr.position), parent))
+            }
+        }
+
+        // simplify when a term is constant and directly determines the outcome
+        val constTrue = NumericLiteral.fromBoolean(true, expr.position)
+        val constFalse = NumericLiteral.fromBoolean(false, expr.position)
+        val newExpr: Expression? = when (expr.operator) {
+            "or" -> {
+                when {
+                    leftVal != null && leftVal.asBooleanValue || rightVal != null && rightVal.asBooleanValue -> constTrue
+                    leftVal != null && !leftVal.asBooleanValue -> expr.right
+                    rightVal != null && !rightVal.asBooleanValue -> expr.left
+                    else -> null
+                }
+            }
+            "and" -> {
+                when {
+                    leftVal != null && !leftVal.asBooleanValue || rightVal != null && !rightVal.asBooleanValue -> constFalse
+                    leftVal != null && leftVal.asBooleanValue -> expr.right
+                    rightVal != null && rightVal.asBooleanValue -> expr.left
+                    else -> null
+                }
+            }
+            "xor" -> {
+                when {
+                    leftVal != null && !leftVal.asBooleanValue -> expr.right
+                    rightVal != null && !rightVal.asBooleanValue -> expr.left
+                    leftVal != null && leftVal.asBooleanValue -> PrefixExpression("not", expr.right, expr.right.position)
+                    rightVal != null && rightVal.asBooleanValue -> PrefixExpression("not", expr.left, expr.left.position)
+                    else -> null
+                }
+            }
+            "|" -> {
+                when {
+                    leftVal?.number==0.0 -> expr.right
+                    rightVal?.number==0.0 -> expr.left
+                    rightIDt.isBytes && rightVal?.number==255.0 -> NumericLiteral(DataType.UBYTE, 255.0, rightVal.position)
+                    rightIDt.isWords && rightVal?.number==65535.0 -> NumericLiteral(DataType.UWORD, 65535.0, rightVal.position)
+                    leftIDt.isBytes && leftVal?.number==255.0 -> NumericLiteral(DataType.UBYTE, 255.0, leftVal.position)
+                    leftIDt.isWords && leftVal?.number==65535.0 -> NumericLiteral(DataType.UWORD, 65535.0, leftVal.position)
+                    else -> null
+                }
+            }
+            "^" -> {
+                when {
+                    leftVal?.number==0.0 -> expr.right
+                    rightVal?.number==0.0 -> expr.left
+                    rightIDt.isBytes && rightVal?.number==255.0 -> PrefixExpression("~", expr.left, expr.left.position)
+                    rightIDt.isWords && rightVal?.number==65535.0 -> PrefixExpression("~", expr.left, expr.left.position)
+                    leftIDt.isBytes && leftVal?.number==255.0 -> PrefixExpression("~", expr.right, expr.right.position)
+                    leftIDt.isWords && leftVal?.number==65535.0 -> PrefixExpression("~", expr.right, expr.right.position)
+                    else -> null
+                }
+            }
+            "&" -> {
+                when {
+                    leftVal?.number==0.0  -> constFalse
+                    rightVal?.number==0.0 -> constFalse
+                    rightIDt.isBytes && rightVal?.number==255.0 -> expr.left
+                    rightIDt.isWords && rightVal?.number==65535.0 -> expr.left
+                    leftIDt.isBytes && leftVal?.number==255.0 -> expr.right
+                    leftIDt.isWords && leftVal?.number==65535.0 -> expr.right
+                    else -> null
+                }
+            }
+            "*" -> optimizeMultiplication(expr, leftVal, rightVal)
+            "/" -> optimizeDivision(expr, leftVal, rightVal)
+            "+" -> optimizeAdd(expr, leftVal, rightVal)
+            "-" -> optimizeSub(expr, leftVal, rightVal)
+            "**" -> optimizePower(expr, leftVal, rightVal)
+            "%" -> optimizeRemainder(expr, leftVal, rightVal)
+            ">>" -> optimizeShiftRight(expr, rightVal)
+            "<<" -> optimizeShiftLeft(expr, rightVal)
+            else -> null
+        }
+
+        if(newExpr != null)
+            return listOf(IAstModification.ReplaceNode(expr, newExpr, parent))
+
+        return noModifications
+    }
+
+    override fun after(functionCallExpr: FunctionCallExpression, parent: Node): Iterable<IAstModification> {
+        if(functionCallExpr.target.nameInSource == listOf("lsb")) {
+            val arg = functionCallExpr.args[0]
+            if(arg is TypecastExpression) {
+                val valueDt = arg.expression.inferType(program)
+                if (valueDt istype DataType.BYTE || valueDt istype DataType.UBYTE) {
+                    // useless lsb() of byte value that was typecasted to word
+                    return listOf(IAstModification.ReplaceNode(functionCallExpr, arg.expression, parent))
+                }
+            } else {
+                val argDt = arg.inferType(program)
+                if (argDt istype DataType.BYTE || argDt istype DataType.UBYTE) {
+                    // useless lsb() of byte value
+                    return listOf(IAstModification.ReplaceNode(functionCallExpr, arg, parent))
+                }
+            }
+        }
+        else if(functionCallExpr.target.nameInSource == listOf("msb")) {
+            val arg = functionCallExpr.args[0]
+            if(arg is TypecastExpression) {
+                val valueDt = arg.expression.inferType(program)
+                if (valueDt istype DataType.BYTE || valueDt istype DataType.UBYTE) {
+                    // useless msb() of byte value that was typecasted to word, replace with 0
+                    return listOf(IAstModification.ReplaceNode(
+                            functionCallExpr,
+                            NumericLiteral(valueDt.getOr(DataType.UBYTE), 0.0, arg.expression.position),
+                            parent))
+                }
+            } else {
+                val argDt = arg.inferType(program)
+                if (argDt istype DataType.BYTE || argDt istype DataType.UBYTE) {
+                    // useless msb() of byte value, replace with 0
+                    return listOf(IAstModification.ReplaceNode(
+                            functionCallExpr,
+                            NumericLiteral(argDt.getOr(DataType.UBYTE), 0.0, arg.position),
+                            parent))
+                }
+            }
+        }
+
+        return noModifications
+    }
+
+    override fun after(containment: ContainmentCheck, parent: Node): Iterable<IAstModification> {
+        val range = containment.iterable as? RangeExpression
+        if(range!=null && range.step.constValue(program)?.number==1.0) {
+            val from = range.from.constValue(program)
+            val to = range.to.constValue(program)
+            val value = containment.element
+            if(from!=null && to!=null && value.isSimple) {
+                if(to.number-from.number>6.0) {
+                    // replace containment test with X>=from and X<=to
+                    val left = BinaryExpression(value, ">=", from, containment.position)
+                    val right = BinaryExpression(value.copy(), "<=", to, containment.position)
+                    val comparison = BinaryExpression(left, "and", right, containment.position)
+                    return listOf(IAstModification.ReplaceNode(containment, comparison, parent))
+                }
+            }
+        }
+        return noModifications
+    }
+
+    override fun after(pipeExpr: PipeExpression, parent: Node) = processPipe(pipeExpr, parent)
+    override fun after(pipe: Pipe, parent: Node) = processPipe(pipe, parent)
+
+    private fun processPipe(pipe: IPipe, parent: Node): Iterable<IAstModification> {
+        if(pipe.source.isSimple) {
+            val segments = pipe.segments
+            if(segments.size==1) {
+                // replace the whole pipe with a normal function call
+                val funcname = (segments[0] as IFunctionCall).target
+                val call = if(pipe is Pipe)
+                    FunctionCallStatement(funcname, mutableListOf(pipe.source), true, pipe.position)
+                else
+                    FunctionCallExpression(funcname, mutableListOf(pipe.source), pipe.position)
+                return listOf(IAstModification.ReplaceNode(pipe as Node, call, parent))
+            } else if(segments.size>1) {
+                // replace source+firstsegment by firstsegment(source) call as the new source
+                val firstSegment = segments.removeAt(0) as IFunctionCall
+                val call = FunctionCallExpression(firstSegment.target, mutableListOf(pipe.source), pipe.position)
+                return listOf(IAstModification.ReplaceNode(pipe.source, call, pipe as Node))
+            }
+        }
+        return noModifications
+    }
+
+    private fun determineY(x: Expression, subBinExpr: BinaryExpression): Expression? {
+        return when {
+            subBinExpr.left isSameAs x -> subBinExpr.right
+            subBinExpr.right isSameAs x -> subBinExpr.left
+            else -> null
+        }
+    }
+
+    private fun optimizeAdd(expr: BinaryExpression, leftVal: NumericLiteral?, rightVal: NumericLiteral?): Expression? {
+        if(expr.left.isSameAs(expr.right)) {
+            // optimize X+X into X *2
+            expr.operator = "*"
+            expr.right = NumericLiteral.optimalInteger(2, expr.right.position)
+            expr.right.linkParents(expr)
+            return expr
+        }
+
+        if (leftVal == null && rightVal == null)
+            return null
+
+        val (expr2, _, rightVal2) = reorderAssociativeWithConstant(expr, leftVal)
+        if (rightVal2 != null) {
+            // right value is a constant, see if we can optimize
+            val rightConst: NumericLiteral = rightVal2
+            when (rightConst.number) {
+                0.0 -> {
+                    // left
+                    return expr2.left
+                }
+            }
+        }
+        // no need to check for left val constant (because of associativity)
+
+        val rnum = rightVal?.number
+        if(rnum!=null && rnum<0.0) {
+            expr.operator = "-"
+            expr.right = NumericLiteral(rightVal.type, -rnum, rightVal.position)
+            return expr
+        }
+
+        return null
+    }
+
+    private fun optimizeSub(expr: BinaryExpression, leftVal: NumericLiteral?, rightVal: NumericLiteral?): Expression? {
+        if(expr.left.isSameAs(expr.right)) {
+            // optimize X-X into 0
+            return NumericLiteral.optimalInteger(0, expr.position)
+        }
+
+        if (leftVal == null && rightVal == null)
+            return null
+
+        if (rightVal != null) {
+            // right value is a constant, see if we can optimize
+            val rnum = rightVal.number
+            if (rnum == 0.0) {
+                // left
+                return expr.left
+            }
+
+            if(rnum<0.0) {
+                expr.operator = "+"
+                expr.right = NumericLiteral(rightVal.type, -rnum, rightVal.position)
+                return expr
+            }
+        }
+        if (leftVal != null) {
+            // left value is a constant, see if we can optimize
+            when (leftVal.number) {
+                0.0 -> {
+                    // -right
+                    return PrefixExpression("-", expr.right, expr.position)
+                }
+            }
+        }
+
+
+        return null
+    }
+
+    private fun optimizePower(expr: BinaryExpression, leftVal: NumericLiteral?, rightVal: NumericLiteral?): Expression? {
+        if (leftVal == null && rightVal == null)
+            return null
+
+        if (rightVal != null) {
+            // right value is a constant, see if we can optimize
+            val rightConst: NumericLiteral = rightVal
+            when (rightConst.number) {
+                -3.0 -> {
+                    // -1/(left*left*left)
+                    return BinaryExpression(NumericLiteral(DataType.FLOAT, -1.0, expr.position), "/",
+                            BinaryExpression(expr.left, "*", BinaryExpression(expr.left, "*", expr.left, expr.position), expr.position),
+                            expr.position)
+                }
+                -2.0 -> {
+                    // -1/(left*left)
+                    return BinaryExpression(NumericLiteral(DataType.FLOAT, -1.0, expr.position), "/",
+                            BinaryExpression(expr.left, "*", expr.left, expr.position),
+                            expr.position)
+                }
+                -1.0 -> {
+                    // -1/left
+                    return BinaryExpression(NumericLiteral(DataType.FLOAT, -1.0, expr.position), "/",
+                            expr.left, expr.position)
+                }
+                0.0 -> {
+                    // 1
+                    return NumericLiteral(rightConst.type, 1.0, expr.position)
+                }
+                0.5 -> {
+                    // sqrt(left)
+                    return FunctionCallExpression(IdentifierReference(listOf("sqrt"), expr.position), mutableListOf(expr.left), expr.position)
+                }
+                1.0 -> {
+                    // left
+                    return expr.left
+                }
+                2.0 -> {
+                    // left*left
+                    return BinaryExpression(expr.left, "*", expr.left, expr.position)
+                }
+                3.0 -> {
+                    // left*left*left
+                    return BinaryExpression(expr.left, "*", BinaryExpression(expr.left, "*", expr.left, expr.position), expr.position)
+                }
+            }
+        }
+        if (leftVal != null) {
+            // left value is a constant, see if we can optimize
+            when (leftVal.number) {
+                -1.0 -> {
+                    // -1
+                    return NumericLiteral(DataType.FLOAT, -1.0, expr.position)
+                }
+                0.0 -> {
+                    // 0
+                    return NumericLiteral(leftVal.type, 0.0, expr.position)
+                }
+                1.0 -> {
+                    //1
+                    return NumericLiteral(leftVal.type, 1.0, expr.position)
+                }
+
+            }
+        }
+
+        return null
+    }
+
+    private fun optimizeRemainder(expr: BinaryExpression, leftVal: NumericLiteral?, rightVal: NumericLiteral?): Expression? {
+        if (leftVal == null && rightVal == null)
+            return null
+
+        // simplify assignments  A = B <operator> C
+
+        val cv = rightVal?.number?.toInt()?.toDouble()
+        when (expr.operator) {
+            "%" -> {
+                if (cv == 1.0) {
+                    val idt = expr.inferType(program)
+                    if(!idt.isKnown)
+                        throw FatalAstException("unknown dt")
+                    return NumericLiteral(idt.getOr(DataType.UNDEFINED), 0.0, expr.position)
+                } else if (cv in powersOfTwo) {
+                    expr.operator = "&"
+                    expr.right = NumericLiteral.optimalInteger(cv!!.toInt()-1, expr.position)
+                    return null
+                }
+            }
+        }
+        return null
+
+    }
+
+    private fun optimizeDivision(expr: BinaryExpression, leftVal: NumericLiteral?, rightVal: NumericLiteral?): Expression? {
+        if (leftVal == null && rightVal == null)
+            return null
+
+        // cannot shuffle assiciativity with division!
+        if (rightVal != null) {
+            // right value is a constant, see if we can optimize
+            val rightConst: NumericLiteral = rightVal
+            val cv = rightConst.number
+            val leftIDt = expr.left.inferType(program)
+            if (!leftIDt.isKnown)
+                return null
+            val leftDt = leftIDt.getOr(DataType.UNDEFINED)
+            when (cv) {
+                -1.0 -> {
+                    //  '/' -> -left
+                    if (expr.operator == "/") {
+                        return PrefixExpression("-", expr.left, expr.position)
+                    }
+                }
+                1.0 -> {
+                    //  '/' -> left
+                    if (expr.operator == "/") {
+                        return expr.left
+                    }
+                }
+                in powersOfTwo -> {
+                    if (leftDt in IntegerDatatypes) {
+                        // divided by a power of two => shift right
+                        val numshifts = log2(cv).toInt()
+                        return BinaryExpression(expr.left, ">>", NumericLiteral.optimalInteger(numshifts, expr.position), expr.position)
+                    }
+                }
+                in negativePowersOfTwo -> {
+                    if (leftDt in IntegerDatatypes) {
+                        // divided by a negative power of two => negate, then shift right
+                        val numshifts = log2(-cv).toInt()
+                        return BinaryExpression(PrefixExpression("-", expr.left, expr.position), ">>", NumericLiteral.optimalInteger(numshifts, expr.position), expr.position)
+                    }
+                }
+            }
+
+            if (leftDt == DataType.UBYTE) {
+                if (abs(rightConst.number) >= 256.0) {
+                    return NumericLiteral(DataType.UBYTE, 0.0, expr.position)
+                }
+            } else if (leftDt == DataType.UWORD) {
+                if (abs(rightConst.number) >= 65536.0) {
+                    return NumericLiteral(DataType.UBYTE, 0.0, expr.position)
+                }
+            }
+        }
+
+        if (leftVal != null) {
+            // left value is a constant, see if we can optimize
+            when (leftVal.number) {
+                0.0 -> {
+                    // 0
+                    return NumericLiteral(leftVal.type, 0.0, expr.position)
+                }
+            }
+        }
+
+        return null
+    }
+
+    private fun optimizeMultiplication(expr: BinaryExpression, leftVal: NumericLiteral?, rightVal: NumericLiteral?): Expression? {
+        if (leftVal == null && rightVal == null)
+            return null
+
+        val (expr2, _, rightVal2) = reorderAssociativeWithConstant(expr, leftVal)
+        if (rightVal2 != null) {
+            // right value is a constant, see if we can optimize
+            val leftValue: Expression = expr2.left
+            val rightConst: NumericLiteral = rightVal2
+            when (val cv = rightConst.number) {
+                -1.0 -> {
+                    // -left
+                    return PrefixExpression("-", leftValue, expr.position)
+                }
+                0.0 -> {
+                    // 0
+                    return NumericLiteral(rightConst.type, 0.0, expr.position)
+                }
+                1.0 -> {
+                    // left
+                    return expr2.left
+                }
+                in powersOfTwo -> {
+                    if (leftValue.inferType(program).isInteger) {
+                        // times a power of two => shift left
+                        val numshifts = log2(cv).toInt()
+                        return BinaryExpression(expr2.left, "<<", NumericLiteral.optimalInteger(numshifts, expr.position), expr.position)
+                    }
+                }
+                in negativePowersOfTwo -> {
+                    if (leftValue.inferType(program).isInteger) {
+                        // times a negative power of two => negate, then shift left
+                        val numshifts = log2(-cv).toInt()
+                        return BinaryExpression(PrefixExpression("-", expr2.left, expr.position), "<<", NumericLiteral.optimalInteger(numshifts, expr.position), expr.position)
+                    }
+                }
+            }
+        }
+        // no need to check for left val constant (because of associativity)
+
+        return null
+    }
+
+    private fun optimizeShiftLeft(expr: BinaryExpression, amountLv: NumericLiteral?): Expression? {
+        if (amountLv == null)
+            return null
+
+        val amount = amountLv.number.toInt()
+        if (amount == 0) {
+            return expr.left
+        }
+        val targetIDt = expr.left.inferType(program)
+        if(!targetIDt.isKnown)
+            throw FatalAstException("unknown dt")
+        when (val targetDt = targetIDt.getOr(DataType.UNDEFINED)) {
+            DataType.UBYTE, DataType.BYTE -> {
+                if (amount >= 8) {
+                    return NumericLiteral(targetDt, 0.0, expr.position)
+                }
+            }
+            DataType.UWORD, DataType.WORD -> {
+                if (amount >= 16) {
+                    return NumericLiteral(targetDt, 0.0, expr.position)
+                } else if (amount > 8) {
+                    val lsb = FunctionCallExpression(IdentifierReference(listOf("lsb"), expr.position), mutableListOf(expr.left), expr.position)
+                    val shifted = BinaryExpression(lsb, "<<", NumericLiteral.optimalInteger(amount - 8, expr.position), expr.position)
+                    return FunctionCallExpression(IdentifierReference(listOf("mkword"), expr.position), mutableListOf(shifted, NumericLiteral.optimalInteger(0, expr.position)), expr.position)
+                }
+            }
+            else -> {
+            }
+        }
+        return null
+    }
+
+    private fun optimizeShiftRight(expr: BinaryExpression, amountLv: NumericLiteral?): Expression? {
+        if (amountLv == null)
+            return null
+
+        val amount = amountLv.number.toInt()
+        if (amount == 0) {
+            return expr.left
+        }
+        val idt = expr.left.inferType(program)
+        if(!idt.isKnown)
+            throw FatalAstException("unknown dt")
+        when (idt.getOr(DataType.UNDEFINED)) {
+            DataType.UBYTE -> {
+                if (amount >= 8) {
+                    return NumericLiteral.optimalInteger(0, expr.position)
+                }
+            }
+            DataType.BYTE -> {
+                if (amount > 8) {
+                    expr.right = NumericLiteral.optimalInteger(8, expr.right.position)
+                    return null
+                }
+            }
+            DataType.UWORD -> {
+                if (amount >= 16) {
+                    return NumericLiteral.optimalInteger(0, expr.position)
+                }
+                else if (amount > 8) {
+                    val msb = FunctionCallExpression(IdentifierReference(listOf("msb"), expr.position), mutableListOf(expr.left), expr.position)
+                    return TypecastExpression(BinaryExpression(msb, ">>", NumericLiteral.optimalInteger(amount - 8, expr.position), expr.position), DataType.UWORD, true, expr.position)
+                }
+            }
+            DataType.WORD -> {
+                if (amount > 16) {
+                    expr.right = NumericLiteral.optimalInteger(16, expr.right.position)
+                    return null
+                }
+            }
+            else -> {
+            }
+        }
+        return null
+    }
+
+    private fun reorderAssociativeWithConstant(expr: BinaryExpression, leftVal: NumericLiteral?): BinExprWithConstants {
+        if (expr.operator in AssociativeOperators && leftVal != null) {
+            // swap left and right so that right is always the constant
+            val tmp = expr.left
+            expr.left = expr.right
+            expr.right = tmp
+            return BinExprWithConstants(expr, expr.right.constValue(program), leftVal)
+        }
+        return BinExprWithConstants(expr, leftVal, expr.right.constValue(program))
+    }
+
+    private data class BinExprWithConstants(val expr: BinaryExpression, val leftVal: NumericLiteral?, val rightVal: NumericLiteral?)
+
+}

codeOptimizers/src/prog8/optimizer/Extensions.kt

@@ -0,0 +1,67 @@
+package prog8.optimizer
+
+import prog8.ast.IBuiltinFunctions
+import prog8.ast.Program
+import prog8.compilerinterface.CompilationOptions
+import prog8.compilerinterface.ICompilationTarget
+import prog8.compilerinterface.IErrorReporter
+
+
+fun Program.constantFold(errors: IErrorReporter, compTarget: ICompilationTarget) {
+    val valuetypefixer = VarConstantValueTypeAdjuster(this, errors)
+    valuetypefixer.visit(this)
+    if(errors.noErrors()) {
+        valuetypefixer.applyModifications()
+
+        val replacer = ConstantIdentifierReplacer(this, errors, compTarget)
+        replacer.visit(this)
+        if (errors.noErrors()) {
+            replacer.applyModifications()
+
+            valuetypefixer.visit(this)
+            if(errors.noErrors()) {
+                valuetypefixer.applyModifications()
+
+                val optimizer = ConstantFoldingOptimizer(this)
+                optimizer.visit(this)
+                while (errors.noErrors() && optimizer.applyModifications() > 0) {
+                    optimizer.visit(this)
+                }
+
+                if (errors.noErrors()) {
+                    replacer.visit(this)
+                    replacer.applyModifications()
+                }
+            }
+        }
+    }
+
+    if(errors.noErrors())
+        modules.forEach { it.linkParents(namespace) }   // re-link in final configuration
+}
+
+
+fun Program.optimizeStatements(errors: IErrorReporter,
+                               functions: IBuiltinFunctions,
+                               compTarget: ICompilationTarget
+): Int {
+    val optimizer = StatementOptimizer(this, errors, functions, compTarget)
+    optimizer.visit(this)
+    val optimizationCount = optimizer.applyModifications()
+
+    modules.forEach { it.linkParents(this.namespace) }   // re-link in final configuration
+
+    return optimizationCount
+}
+
+fun Program.simplifyExpressions(errors: IErrorReporter) : Int {
+    val opti = ExpressionSimplifier(this, errors)
+    opti.visit(this)
+    return opti.applyModifications()
+}
+
+fun Program.splitBinaryExpressions(options: CompilationOptions, compTarget: ICompilationTarget) : Int {
+    val opti = BinExprSplitter(this, options, compTarget)
+    opti.visit(this)
+    return opti.applyModifications()
+}

codeOptimizers/src/prog8/optimizer/StatementOptimizer.kt

@@ -0,0 +1,502 @@
+package prog8.optimizer
+
+import prog8.ast.*
+import prog8.ast.base.ArrayDatatypes
+import prog8.ast.base.DataType
+import prog8.ast.base.IntegerDatatypes
+import prog8.ast.base.VarDeclType
+import prog8.ast.expressions.*
+import prog8.ast.statements.*
+import prog8.ast.walk.AstWalker
+import prog8.ast.walk.IAstModification
+import prog8.compilerinterface.ICompilationTarget
+import prog8.compilerinterface.IErrorReporter
+import kotlin.math.floor
+
+
+class StatementOptimizer(private val program: Program,
+                                  private val errors: IErrorReporter,
+                                  private val functions: IBuiltinFunctions,
+                                  private val compTarget: ICompilationTarget
+) : AstWalker() {
+
+    override fun before(functionCallExpr: FunctionCallExpression, parent: Node): Iterable<IAstModification> {
+        // if the first instruction in the called subroutine is a return statement with a simple value (NOT being a parameter),
+        // remove the jump altogeter and inline the returnvalue directly.
+
+        fun scopePrefix(variable: IdentifierReference): IdentifierReference {
+            val target = variable.targetStatement(program) as INamedStatement
+            return IdentifierReference(target.scopedName, variable.position)
+        }
+
+        val subroutine = functionCallExpr.target.targetSubroutine(program)
+        if(subroutine!=null) {
+            val first = subroutine.statements.asSequence().filterNot { it is VarDecl || it is Directive }.firstOrNull()
+            if(first is Return && first.value?.isSimple==true) {
+                val copy = when(val orig = first.value!!) {
+                    is AddressOf -> {
+                        val scoped = scopePrefix(orig.identifier)
+                        AddressOf(scoped, orig.position)
+                    }
+                    is DirectMemoryRead -> {
+                        when(val expr = orig.addressExpression) {
+                            is NumericLiteral -> DirectMemoryRead(expr.copy(), orig.position)
+                            else -> return noModifications
+                        }
+                    }
+                    is IdentifierReference -> {
+                        if(orig.targetVarDecl(program)?.origin == VarDeclOrigin.SUBROUTINEPARAM)
+                            return noModifications
+                        else
+                            scopePrefix(orig)
+                    }
+                    is NumericLiteral -> orig.copy()
+                    is StringLiteral -> orig.copy()
+                    else -> return noModifications
+                }
+                return listOf(IAstModification.ReplaceNode(functionCallExpr, copy, parent))
+            }
+        }
+        return noModifications
+    }
+
+    override fun after(functionCallStatement: FunctionCallStatement, parent: Node): Iterable<IAstModification> {
+        if(functionCallStatement.target.nameInSource.size==1) {
+            val functionName = functionCallStatement.target.nameInSource[0]
+            if (functionName in functions.purefunctionNames) {
+                errors.warn("statement has no effect (function return value is discarded)", functionCallStatement.position)
+                return listOf(IAstModification.Remove(functionCallStatement, parent as IStatementContainer))
+            }
+        }
+
+        // printing a literal string of just 2 or 1 characters is replaced by directly outputting those characters
+        // only do this optimization if the arg is a known-constant string literal instead of a user defined variable.
+        if(functionCallStatement.target.nameInSource==listOf("txt", "print")) {
+            val arg = functionCallStatement.args.single()
+            val stringVar: IdentifierReference? = if(arg is AddressOf) {
+                arg.identifier
+            } else {
+                arg as? IdentifierReference
+            }
+            if(stringVar!=null && stringVar.wasStringLiteral(program)) {
+                val string = stringVar.targetVarDecl(program)?.value as? StringLiteral
+                if(string!=null) {
+                    val pos = functionCallStatement.position
+                    if (string.value.length == 1) {
+                        val firstCharEncoded = compTarget.encodeString(string.value, string.encoding)[0]
+                        val chrout = FunctionCallStatement(
+                            IdentifierReference(listOf("txt", "chrout"), pos),
+                            mutableListOf(NumericLiteral(DataType.UBYTE, firstCharEncoded.toDouble(), pos)),
+                            functionCallStatement.void, pos
+                        )
+                        val stringDecl = string.parent as VarDecl
+                        return listOf(
+                            IAstModification.ReplaceNode(functionCallStatement, chrout, parent),
+                            IAstModification.Remove(stringDecl, stringDecl.parent as IStatementContainer)
+                        )
+                    } else if (string.value.length == 2) {
+                        val firstTwoCharsEncoded = compTarget.encodeString(string.value.take(2), string.encoding)
+                        val chrout1 = FunctionCallStatement(
+                            IdentifierReference(listOf("txt", "chrout"), pos),
+                            mutableListOf(NumericLiteral(DataType.UBYTE, firstTwoCharsEncoded[0].toDouble(), pos)),
+                            functionCallStatement.void, pos
+                        )
+                        val chrout2 = FunctionCallStatement(
+                            IdentifierReference(listOf("txt", "chrout"), pos),
+                            mutableListOf(NumericLiteral(DataType.UBYTE, firstTwoCharsEncoded[1].toDouble(), pos)),
+                            functionCallStatement.void, pos
+                        )
+                        val stringDecl = string.parent as VarDecl
+                        return listOf(
+                            IAstModification.InsertBefore(functionCallStatement, chrout1, parent as IStatementContainer),
+                            IAstModification.ReplaceNode(functionCallStatement, chrout2, parent),
+                            IAstModification.Remove(stringDecl, stringDecl.parent as IStatementContainer)
+                        )
+                    }
+                }
+            }
+        }
+
+        // if the first instruction in the called subroutine is a return statement, remove the jump altogeter
+        val subroutine = functionCallStatement.target.targetSubroutine(program)
+        if(subroutine!=null) {
+            val first = subroutine.statements.asSequence().filterNot { it is VarDecl || it is Directive }.firstOrNull()
+            if(first is Return)
+                return listOf(IAstModification.Remove(functionCallStatement, parent as IStatementContainer))
+        }
+
+        // see if we can optimize any complex argument expressions to be just a simple variable
+        // TODO for now, only works for single-argument functions because we use just 1 temp var: R9
+        if(functionCallStatement.target.nameInSource !in listOf(listOf("pop"), listOf("popw")) && functionCallStatement.args.size==1) {
+            val arg = functionCallStatement.args[0]
+            if(!arg.isSimple && arg !is IFunctionCall) {
+                val name = getTempRegisterName(arg.inferType(program))
+                val tempvar = IdentifierReference(name, functionCallStatement.position)
+                val assignTempvar = Assignment(AssignTarget(tempvar.copy(), null, null, functionCallStatement.position), arg, AssignmentOrigin.OPTIMIZER, functionCallStatement.position)
+                return listOf(
+                    IAstModification.InsertBefore(functionCallStatement, assignTempvar, parent as IStatementContainer),
+                    IAstModification.ReplaceNode(arg, tempvar, functionCallStatement)
+                )
+            }
+        }
+
+
+        return noModifications
+    }
+
+    override fun after(ifElse: IfElse, parent: Node): Iterable<IAstModification> {
+        // remove empty if statements
+        if(ifElse.truepart.isEmpty() && ifElse.elsepart.isEmpty())
+            return listOf(IAstModification.Remove(ifElse, parent as IStatementContainer))
+
+        // empty true part? switch with the else part
+        if(ifElse.truepart.isEmpty() && ifElse.elsepart.isNotEmpty()) {
+            val invertedCondition = PrefixExpression("not", ifElse.condition, ifElse.condition.position)
+            val emptyscope = AnonymousScope(mutableListOf(), ifElse.elsepart.position)
+            val truepart = AnonymousScope(ifElse.elsepart.statements, ifElse.truepart.position)
+            return listOf(
+                    IAstModification.ReplaceNode(ifElse.condition, invertedCondition, ifElse),
+                    IAstModification.ReplaceNode(ifElse.truepart, truepart, ifElse),
+                    IAstModification.ReplaceNode(ifElse.elsepart, emptyscope, ifElse)
+            )
+        }
+
+        val constvalue = ifElse.condition.constValue(program)
+        if(constvalue!=null) {
+            return if(constvalue.asBooleanValue){
+                // always true -> keep only if-part
+                errors.warn("condition is always true", ifElse.condition.position)
+                listOf(IAstModification.ReplaceNode(ifElse, ifElse.truepart, parent))
+            } else {
+                // always false -> keep only else-part
+                errors.warn("condition is always false", ifElse.condition.position)
+                listOf(IAstModification.ReplaceNode(ifElse, ifElse.elsepart, parent))
+            }
+        }
+
+        return noModifications
+    }
+
+    override fun after(forLoop: ForLoop, parent: Node): Iterable<IAstModification> {
+        if(forLoop.body.isEmpty()) {
+            errors.warn("removing empty for loop", forLoop.position)
+            return listOf(IAstModification.Remove(forLoop, parent as IStatementContainer))
+        } else if(forLoop.body.statements.size==1) {
+            val loopvar = forLoop.body.statements[0] as? VarDecl
+            if(loopvar!=null && loopvar.name==forLoop.loopVar.nameInSource.singleOrNull()) {
+                // remove empty for loop (only loopvar decl in it)
+                return listOf(IAstModification.Remove(forLoop, parent as IStatementContainer))
+            }
+        }
+
+        val range = forLoop.iterable as? RangeExpression
+        if(range!=null) {
+            if (range.size() == 1) {
+                // for loop over a (constant) range of just a single value-- optimize the loop away
+                // loopvar/reg = range value , follow by block
+                val scope = AnonymousScope(mutableListOf(), forLoop.position)
+                scope.statements.add(Assignment(AssignTarget(forLoop.loopVar, null, null, forLoop.position), range.from, AssignmentOrigin.OPTIMIZER, forLoop.position))
+                scope.statements.addAll(forLoop.body.statements)
+                return listOf(IAstModification.ReplaceNode(forLoop, scope, parent))
+            }
+        }
+        val iterable = (forLoop.iterable as? IdentifierReference)?.targetVarDecl(program)
+        if(iterable!=null) {
+            if(iterable.datatype==DataType.STR) {
+                val sv = iterable.value as StringLiteral
+                val size = sv.value.length
+                if(size==1) {
+                    // loop over string of length 1 -> just assign the single character
+                    val character = compTarget.encodeString(sv.value, sv.encoding)[0]
+                    val byte = NumericLiteral(DataType.UBYTE, character.toDouble(), iterable.position)
+                    val scope = AnonymousScope(mutableListOf(), forLoop.position)
+                    scope.statements.add(Assignment(AssignTarget(forLoop.loopVar, null, null, forLoop.position), byte, AssignmentOrigin.OPTIMIZER, forLoop.position))
+                    scope.statements.addAll(forLoop.body.statements)
+                    return listOf(IAstModification.ReplaceNode(forLoop, scope, parent))
+                }
+            }
+            else if(iterable.datatype in ArrayDatatypes) {
+                val size = iterable.arraysize!!.constIndex()
+                if(size==1) {
+                    // loop over array of length 1 -> just assign the single value
+                    val av = (iterable.value as ArrayLiteral).value[0].constValue(program)?.number
+                    if(av!=null) {
+                        val scope = AnonymousScope(mutableListOf(), forLoop.position)
+                        scope.statements.add(Assignment(
+                                AssignTarget(forLoop.loopVar, null, null, forLoop.position), NumericLiteral.optimalInteger(av.toInt(), iterable.position),
+                                AssignmentOrigin.OPTIMIZER, forLoop.position))
+                        scope.statements.addAll(forLoop.body.statements)
+                        return listOf(IAstModification.ReplaceNode(forLoop, scope, parent))
+                    }
+                }
+            }
+        }
+
+        return noModifications
+    }
+
+    override fun before(untilLoop: UntilLoop, parent: Node): Iterable<IAstModification> {
+        val constvalue = untilLoop.condition.constValue(program)
+        if(constvalue!=null) {
+            return if(constvalue.asBooleanValue) {
+                // always true -> keep only the statement block
+                errors.warn("condition is always true", untilLoop.condition.position)
+                listOf(IAstModification.ReplaceNode(untilLoop, untilLoop.body, parent))
+            } else {
+                // always false
+                val forever = RepeatLoop(null, untilLoop.body, untilLoop.position)
+                listOf(IAstModification.ReplaceNode(untilLoop, forever, parent))
+            }
+        }
+        return noModifications
+    }
+
+    override fun before(whileLoop: WhileLoop, parent: Node): Iterable<IAstModification> {
+        val constvalue = whileLoop.condition.constValue(program)
+        if(constvalue!=null) {
+            return if(constvalue.asBooleanValue) {
+                // always true
+                val forever = RepeatLoop(null, whileLoop.body, whileLoop.position)
+                listOf(IAstModification.ReplaceNode(whileLoop, forever, parent))
+            } else {
+                // always false -> remove the while statement altogether
+                errors.warn("condition is always false", whileLoop.condition.position)
+                listOf(IAstModification.Remove(whileLoop, parent as IStatementContainer))
+            }
+        }
+        return noModifications
+    }
+
+    override fun after(repeatLoop: RepeatLoop, parent: Node): Iterable<IAstModification> {
+        val iter = repeatLoop.iterations
+        if(iter!=null) {
+            if(repeatLoop.body.isEmpty()) {
+                errors.warn("empty loop removed", repeatLoop.position)
+                return listOf(IAstModification.Remove(repeatLoop, parent as IStatementContainer))
+            }
+            val iterations = iter.constValue(program)?.number?.toInt()
+            if (iterations == 0) {
+                errors.warn("iterations is always 0, removed loop", iter.position)
+                return listOf(IAstModification.Remove(repeatLoop, parent as IStatementContainer))
+            }
+            if (iterations == 1) {
+                errors.warn("iterations is always 1", iter.position)
+                return listOf(IAstModification.ReplaceNode(repeatLoop, repeatLoop.body, parent))
+            }
+        }
+        return noModifications
+    }
+
+
+    // NOTE: do NOT remove a jump to the next statement, because this will lead to wrong code when this occurs at the end of a subroutine
+    // if we want to optimize this away, it can be done later at code generation time.
+
+    override fun after(gosub: GoSub, parent: Node): Iterable<IAstModification> {
+        // if the next statement is return with no returnvalue, change into a regular jump if there are no parameters as well.
+        val subroutineParams = gosub.identifier?.targetSubroutine(program)?.parameters
+        if(subroutineParams!=null && subroutineParams.isEmpty()) {
+            val returnstmt = gosub.nextSibling() as? Return
+            if(returnstmt!=null && returnstmt.value==null) {
+                return listOf(
+                    IAstModification.Remove(returnstmt, parent as IStatementContainer),
+                    IAstModification.ReplaceNode(gosub, Jump(gosub.address, gosub.identifier, gosub.generatedLabel, gosub.position), parent)
+                )
+            }
+        }
+        return noModifications
+    }
+
+    override fun before(assignment: Assignment, parent: Node): Iterable<IAstModification> {
+
+        val binExpr = assignment.value as? BinaryExpression
+        if(binExpr!=null) {
+            if(binExpr.left isSameAs assignment.target) {
+                val rExpr = binExpr.right as? BinaryExpression
+                if(rExpr!=null) {
+                    val op1 = binExpr.operator
+                    val op2 = rExpr.operator
+
+                    if(rExpr.left is NumericLiteral && op2 in AssociativeOperators) {
+                        // associative operator, make sure the constant numeric value is second (right)
+                        return listOf(IAstModification.SwapOperands(rExpr))
+                    }
+
+                    val rNum = (rExpr.right as? NumericLiteral)?.number
+                    if(rNum!=null) {
+                        if (op1 == "+" || op1 == "-") {
+                            if (op2 == "+") {
+                                // A = A +/- B + N  --->  A = A +/- B  ;  A = A + N
+                                val expr2 = BinaryExpression(binExpr.left, binExpr.operator, rExpr.left, binExpr.position)
+                                val addConstant = Assignment(
+                                        assignment.target.copy(),
+                                        BinaryExpression(binExpr.left.copy(), "+", rExpr.right, rExpr.position),
+                                        AssignmentOrigin.OPTIMIZER, assignment.position
+                                )
+                                return listOf(
+                                        IAstModification.ReplaceNode(binExpr, expr2, binExpr.parent),
+                                        IAstModification.InsertAfter(assignment, addConstant, parent as IStatementContainer))
+                            } else if (op2 == "-") {
+                                // A = A +/- B - N  --->  A = A +/- B  ;  A = A - N
+                                val expr2 = BinaryExpression(binExpr.left, binExpr.operator, rExpr.left, binExpr.position)
+                                val subConstant = Assignment(
+                                        assignment.target.copy(),
+                                        BinaryExpression(binExpr.left.copy(), "-", rExpr.right, rExpr.position),
+                                        AssignmentOrigin.OPTIMIZER, assignment.position
+                                )
+                                return listOf(
+                                        IAstModification.ReplaceNode(binExpr, expr2, binExpr.parent),
+                                        IAstModification.InsertAfter(assignment, subConstant, parent as IStatementContainer))
+                            }
+                        }
+                    }
+                }
+            }
+
+            if(binExpr.operator in AssociativeOperators && binExpr.right isSameAs assignment.target) {
+                // associative operator, swap the operands so that the assignment target is first (left)
+                // unless the other operand is the same in which case we don't swap (endless loop!)
+                if (!(binExpr.left isSameAs binExpr.right))
+                    return listOf(IAstModification.SwapOperands(binExpr))
+            }
+
+        }
+
+        return noModifications
+    }
+
+    override fun after(assignment: Assignment, parent: Node): Iterable<IAstModification> {
+        if(assignment.target isSameAs assignment.value) {
+            // remove assignment to self
+            return listOf(IAstModification.Remove(assignment, parent as IStatementContainer))
+        }
+
+        val targetIDt = assignment.target.inferType(program)
+        if(!targetIDt.isKnown)
+            return noModifications
+
+        // optimize binary expressions a bit
+        val bexpr=assignment.value as? BinaryExpression
+        if(bexpr!=null) {
+            val rightCv = bexpr.right.constValue(program)?.number
+            if(bexpr.operator=="-" && rightCv==null) {
+                if(bexpr.right isSameAs assignment.target) {
+                    // X = value - X  -->  X = -X ; X += value  (to avoid need of stack-evaluation)
+                    val negation = PrefixExpression("-", bexpr.right.copy(), bexpr.position)
+                    val addValue = Assignment(assignment.target.copy(), BinaryExpression(bexpr.right, "+", bexpr.left, bexpr.position), AssignmentOrigin.OPTIMIZER, assignment.position)
+                    return listOf(
+                        IAstModification.ReplaceNode(bexpr, negation, assignment),
+                        IAstModification.InsertAfter(assignment, addValue, parent as IStatementContainer)
+                    )
+                }
+            }
+
+            if (rightCv != null && assignment.target isSameAs bexpr.left) {
+                // assignments of the form:  X = X <operator> <expr>
+                // remove assignments that have no effect (such as X=X+0)
+                // optimize/rewrite some other expressions
+                val targetDt = targetIDt.getOr(DataType.UNDEFINED)
+                val vardeclDt = (assignment.target.identifier?.targetVarDecl(program))?.type
+                when (bexpr.operator) {
+                    "+" -> {
+                        if (rightCv == 0.0) {
+                            return listOf(IAstModification.Remove(assignment, parent as IStatementContainer))
+                        } else if (targetDt in IntegerDatatypes && floor(rightCv) == rightCv) {
+                            if (vardeclDt != VarDeclType.MEMORY && rightCv in 1.0..4.0) {
+                                // replace by several INCs if it's not a memory address (inc on a memory mapped register doesn't work very well)
+                                val incs = AnonymousScope(mutableListOf(), assignment.position)
+                                repeat(rightCv.toInt()) {
+                                    incs.statements.add(PostIncrDecr(assignment.target.copy(), "++", assignment.position))
+                                }
+                                listOf(IAstModification.ReplaceNode(assignment, if(incs.statements.size==1) incs.statements[0] else incs, parent))
+                            }
+                        }
+                    }
+                    "-" -> {
+                        if (rightCv == 0.0) {
+                            return listOf(IAstModification.Remove(assignment, parent as IStatementContainer))
+                        } else if (targetDt in IntegerDatatypes && floor(rightCv) == rightCv) {
+                            if (vardeclDt != VarDeclType.MEMORY && rightCv in 1.0..4.0) {
+                                // replace by several DECs if it's not a memory address (dec on a memory mapped register doesn't work very well)
+                                val decs = AnonymousScope(mutableListOf(), assignment.position)
+                                repeat(rightCv.toInt()) {
+                                    decs.statements.add(PostIncrDecr(assignment.target.copy(), "--", assignment.position))
+                                }
+                                return listOf(IAstModification.ReplaceNode(assignment, decs, parent))
+                            }
+                        }
+                    }
+                    "*" -> if (rightCv == 1.0) return listOf(IAstModification.Remove(assignment, parent as IStatementContainer))
+                    "/" -> if (rightCv == 1.0) return listOf(IAstModification.Remove(assignment, parent as IStatementContainer))
+                    "**" -> if (rightCv == 1.0) return listOf(IAstModification.Remove(assignment, parent as IStatementContainer))
+                    "|" -> if (rightCv == 0.0) return listOf(IAstModification.Remove(assignment, parent as IStatementContainer))
+                    "^" -> if (rightCv == 0.0) return listOf(IAstModification.Remove(assignment, parent as IStatementContainer))
+                    "<<" -> {
+                        if (rightCv == 0.0)
+                            return listOf(IAstModification.Remove(assignment, parent as IStatementContainer))
+                    }
+                    ">>" -> {
+                        if (rightCv == 0.0)
+                            return listOf(IAstModification.Remove(assignment, parent as IStatementContainer))
+                    }
+                }
+
+            }
+        }
+
+        // word = msb(word) , word=lsb(word)
+        if(assignment.target.inferType(program).isWords) {
+            var fcall = assignment.value as? FunctionCallExpression
+            if (fcall == null)
+                fcall = (assignment.value as? TypecastExpression)?.expression as? FunctionCallExpression
+            if (fcall != null && (fcall.target.nameInSource == listOf("lsb") || fcall.target.nameInSource == listOf("msb"))) {
+                if (fcall.args.single() isSameAs assignment.target) {
+                    return if (fcall.target.nameInSource == listOf("lsb")) {
+                        // optimize word=lsb(word) ==>  word &= $00ff
+                        val and255 = BinaryExpression(fcall.args[0], "&", NumericLiteral(DataType.UWORD, 255.0, fcall.position), fcall.position)
+                        val newAssign = Assignment(assignment.target, and255, AssignmentOrigin.OPTIMIZER, fcall.position)
+                        listOf(IAstModification.ReplaceNode(assignment, newAssign, parent))
+                    } else {
+                        // optimize word=msb(word) ==>  word >>= 8
+                        val shift8 = BinaryExpression(fcall.args[0], ">>", NumericLiteral(DataType.UBYTE, 8.0, fcall.position), fcall.position)
+                        val newAssign = Assignment(assignment.target, shift8, AssignmentOrigin.OPTIMIZER, fcall.position)
+                        listOf(IAstModification.ReplaceNode(assignment, newAssign, parent))
+                    }
+                }
+            }
+        }
+
+        return noModifications
+    }
+
+    override fun after(returnStmt: Return, parent: Node): Iterable<IAstModification> {
+        fun returnViaIntermediaryVar(value: Expression): Iterable<IAstModification>? {
+            val subr = returnStmt.definingSubroutine!!
+            val returnDt = subr.returntypes.single()
+            if (returnDt in IntegerDatatypes) {
+                // first assign to intermediary variable, then return that
+                val (returnVarName, _) = program.getTempVar(returnDt)
+                val returnValueIntermediary = IdentifierReference(returnVarName, returnStmt.position)
+                val tgt = AssignTarget(returnValueIntermediary, null, null, returnStmt.position)
+                val assign = Assignment(tgt, value, AssignmentOrigin.OPTIMIZER, returnStmt.position)
+                val returnReplacement = Return(returnValueIntermediary.copy(), returnStmt.position)
+                return listOf(
+                    IAstModification.InsertBefore(returnStmt, assign, parent as IStatementContainer),
+                    IAstModification.ReplaceNode(returnStmt, returnReplacement, parent)
+                )
+            }
+            return null
+        }
+
+        // TODO decision when to use intermediary variable to calculate returnvalue seems a bit arbitrary...
+        val returnvalue = returnStmt.value
+        if (returnvalue!=null) {
+            if (returnvalue is BinaryExpression || (returnvalue is TypecastExpression && !returnvalue.expression.isSimple)) {
+                val mod = returnViaIntermediaryVar(returnvalue)
+                if(mod!=null)
+                    return mod
+            }
+        }
+
+        return noModifications
+    }
+}

codeOptimizers/src/prog8/optimizer/UnusedCodeRemover.kt

@@ -0,0 +1,255 @@
+package prog8.optimizer
+
+import prog8.ast.*
+import prog8.ast.base.DataType
+import prog8.ast.base.VarDeclType
+import prog8.ast.base.defaultZero
+import prog8.ast.expressions.*
+import prog8.ast.statements.*
+import prog8.ast.walk.AstWalker
+import prog8.ast.walk.IAstModification
+import prog8.compilerinterface.CallGraph
+import prog8.compilerinterface.ICompilationTarget
+import prog8.compilerinterface.IErrorReporter
+import prog8.compilerinterface.isIOAddress
+
+
+class UnusedCodeRemover(private val program: Program,
+                        private val errors: IErrorReporter,
+                        private val compTarget: ICompilationTarget
+): AstWalker() {
+
+    private val callgraph = CallGraph(program)
+
+    override fun before(module: Module, parent: Node): Iterable<IAstModification> {
+        return if (!module.isLibrary && (module.containsNoCodeNorVars || callgraph.unused(module)))
+            listOf(IAstModification.Remove(module, parent as IStatementContainer))
+        else
+            noModifications
+    }
+
+    override fun before(breakStmt: Break, parent: Node): Iterable<IAstModification> {
+        reportUnreachable(breakStmt)
+        return emptyList()
+    }
+
+    override fun before(jump: Jump, parent: Node): Iterable<IAstModification> {
+        reportUnreachable(jump)
+        return emptyList()
+    }
+
+    override fun before(returnStmt: Return, parent: Node): Iterable<IAstModification> {
+        reportUnreachable(returnStmt)
+        return emptyList()
+    }
+
+    override fun before(functionCallStatement: FunctionCallStatement, parent: Node): Iterable<IAstModification> {
+        if(functionCallStatement.target.nameInSource.last() == "exit")
+            reportUnreachable(functionCallStatement)
+        return emptyList()
+    }
+
+    private fun reportUnreachable(stmt: Statement) {
+        when(val next = stmt.nextSibling()) {
+            null, is Label, is Directive, is VarDecl, is InlineAssembly, is Subroutine -> {}
+            else -> errors.warn("unreachable code", next.position)
+        }
+    }
+
+    override fun after(scope: AnonymousScope, parent: Node): Iterable<IAstModification> {
+        return deduplicateAssignments(scope.statements, scope)
+    }
+
+    override fun after(block: Block, parent: Node): Iterable<IAstModification> {
+        if("force_output" !in block.options()) {
+            if (block.containsNoCodeNorVars) {
+                if(block.name != internedStringsModuleName)
+                    errors.warn("removing unused block '${block.name}'", block.position)
+                return listOf(IAstModification.Remove(block, parent as IStatementContainer))
+            }
+            if(callgraph.unused(block)) {
+                if(block.statements.any{ it !is VarDecl || it.type==VarDeclType.VAR})
+                    errors.warn("removing unused block '${block.name}'", block.position)
+                program.removeInternedStringsFromRemovedBlock(block)
+                return listOf(IAstModification.Remove(block, parent as IStatementContainer))
+            }
+        }
+
+        return deduplicateAssignments(block.statements, block)
+    }
+
+    override fun after(subroutine: Subroutine, parent: Node): Iterable<IAstModification> {
+        val forceOutput = "force_output" in subroutine.definingBlock.options()
+        if (subroutine !== program.entrypoint && !forceOutput && !subroutine.inline && !subroutine.isAsmSubroutine) {
+            if(callgraph.unused(subroutine)) {
+                if(subroutine.containsNoCodeNorVars) {
+                    if(!subroutine.definingModule.isLibrary)
+                        errors.warn("removing empty subroutine '${subroutine.name}'", subroutine.position)
+                    val removals = mutableListOf(IAstModification.Remove(subroutine, parent as IStatementContainer))
+                    callgraph.calledBy[subroutine]?.let {
+                        for(node in it)
+                            removals.add(IAstModification.Remove(node, node.parent as IStatementContainer))
+                    }
+                    return removals
+                }
+                if(!subroutine.definingModule.isLibrary)
+                    errors.warn("removing unused subroutine '${subroutine.name}'", subroutine.position)
+                program.removeInternedStringsFromRemovedSubroutine(subroutine)
+                return listOf(IAstModification.Remove(subroutine, parent as IStatementContainer))
+            }
+        }
+
+        return deduplicateAssignments(subroutine.statements, subroutine)
+    }
+
+    override fun after(decl: VarDecl, parent: Node): Iterable<IAstModification> {
+        if(decl.type==VarDeclType.VAR) {
+            val block = decl.definingBlock
+            val forceOutput = "force_output" in block.options()
+            if (!forceOutput && decl.origin==VarDeclOrigin.USERCODE && !decl.sharedWithAsm) {
+                val usages = callgraph.usages(decl)
+                if (usages.isEmpty()) {
+                    // if(!decl.definingModule.isLibrary)
+                        errors.warn("removing unused variable '${decl.name}'", decl.position)
+                    return listOf(IAstModification.Remove(decl, parent as IStatementContainer))
+                }
+                else {
+                    if(usages.size==1) {
+                        val singleUse = usages[0].parent
+                        if(singleUse is AssignTarget) {
+                            val assignment = singleUse.parent as Assignment
+                            if(assignment.origin==AssignmentOrigin.VARINIT) {
+                                if(!decl.definingModule.isLibrary)
+                                    errors.warn("removing unused variable '${decl.name}'", decl.position)
+                                return listOf(
+                                    IAstModification.Remove(decl, parent as IStatementContainer),
+                                    IAstModification.Remove(assignment, assignment.parent as IStatementContainer)
+                                )
+                            }
+                        }
+                    }
+                }
+            }
+        }
+
+        return noModifications
+    }
+
+    private fun deduplicateAssignments(statements: List<Statement>, scope: IStatementContainer): List<IAstModification> {
+        // removes 'duplicate' assignments that assign the same target directly after another, unless it is a function call
+        val linesToRemove = mutableListOf<Assignment>()
+        val modifications = mutableListOf<IAstModification>()
+
+        fun substituteZeroInBinexpr(expr: BinaryExpression, zero: NumericLiteral, assign1: Assignment, assign2: Assignment) {
+            if(expr.left isSameAs assign2.target) {
+                // X = X <oper> Right
+                linesToRemove.add(assign1)
+                modifications.add(IAstModification.ReplaceNode(
+                    expr.left, zero, expr
+                ))
+            }
+            if(expr.right isSameAs assign2.target) {
+                // X = Left <oper> X
+                linesToRemove.add(assign1)
+                modifications.add(IAstModification.ReplaceNode(
+                    expr.right, zero, expr
+                ))
+            }
+            val leftBinExpr = expr.left as? BinaryExpression
+            val rightBinExpr = expr.right as? BinaryExpression
+            if(leftBinExpr!=null && rightBinExpr==null) {
+                if(leftBinExpr.left isSameAs assign2.target) {
+                    // X = (X <oper> Right) <oper> Something
+                    linesToRemove.add(assign1)
+                    modifications.add(IAstModification.ReplaceNode(
+                        leftBinExpr.left, zero, leftBinExpr
+                    ))
+                }
+                if(leftBinExpr.right isSameAs assign2.target) {
+                    // X = (Left <oper> X) <oper> Something
+                    linesToRemove.add(assign1)
+                    modifications.add(IAstModification.ReplaceNode(
+                        leftBinExpr.right, zero, leftBinExpr
+                    ))
+                }
+            }
+            if(leftBinExpr==null && rightBinExpr!=null) {
+                if(rightBinExpr.left isSameAs assign2.target) {
+                    // X = Something <oper> (X <oper> Right)
+                    linesToRemove.add(assign1)
+                    modifications.add(IAstModification.ReplaceNode(
+                        rightBinExpr.left, zero, rightBinExpr
+                    ))
+                }
+                if(rightBinExpr.right isSameAs assign2.target) {
+                    // X = Something <oper> (Left <oper> X)
+                    linesToRemove.add(assign1)
+                    modifications.add(IAstModification.ReplaceNode(
+                        rightBinExpr.right, zero, rightBinExpr
+                    ))
+                }
+            }
+        }
+
+        fun substituteZeroInPrefixexpr(expr: PrefixExpression, zero: NumericLiteral, assign1: Assignment, assign2: Assignment) {
+            if(expr.expression isSameAs assign2.target) {
+                linesToRemove.add(assign1)
+                modifications.add(IAstModification.ReplaceNode(
+                    expr.expression, zero, expr
+                ))
+            }
+        }
+
+        fun substituteZeroInTypecast(expr: TypecastExpression, zero: NumericLiteral, assign1: Assignment, assign2: Assignment) {
+            if(expr.expression isSameAs assign2.target) {
+                linesToRemove.add(assign1)
+                modifications.add(IAstModification.ReplaceNode(
+                    expr.expression, zero, expr
+                ))
+            }
+            val subCast = expr.expression as? TypecastExpression
+            if(subCast!=null && subCast.expression isSameAs assign2.target) {
+                linesToRemove.add(assign1)
+                modifications.add(IAstModification.ReplaceNode(
+                    subCast.expression, zero, subCast
+                ))
+            }
+        }
+
+        for (stmtPairs in statements.windowed(2, step = 1)) {
+            val assign1 = stmtPairs[0] as? Assignment
+            val assign2 = stmtPairs[1] as? Assignment
+            if (assign1 != null && assign2 != null) {
+                val cvalue1 = assign1.value.constValue(program)
+                if(cvalue1!=null && cvalue1.number==0.0 && assign2.target.isSameAs(assign1.target, program) && assign2.isAugmentable) {
+                    val value2 = assign2.value
+                    val zero = defaultZero(value2.inferType(program).getOr(DataType.UNDEFINED), value2.position)
+                    when(value2) {
+                        is BinaryExpression -> substituteZeroInBinexpr(value2, zero, assign1, assign2)
+                        is PrefixExpression -> substituteZeroInPrefixexpr(value2, zero, assign1, assign2)
+                        is TypecastExpression -> substituteZeroInTypecast(value2, zero, assign1, assign2)
+                        else -> {}
+                    }
+                } else {
+                    if (assign1.target.isSameAs(assign2.target, program) && !assign1.target.isIOAddress(compTarget.machine))  {
+                        if(assign2.target.identifier==null || !assign2.value.referencesIdentifier(assign2.target.identifier!!.nameInSource))
+                            // only remove the second assignment if its value is a simple expression!
+                            when(assign2.value) {
+                                is PrefixExpression,
+                                is BinaryExpression,
+                                is TypecastExpression,
+                                is PipeExpression,
+                                is IFunctionCall -> { /* don't remove */ }
+                                else -> {
+                                    if(assign1.value !is IFunctionCall)
+                                        linesToRemove.add(assign1)
+                                }
+                            }
+                    }
+                }
+            }
+        }
+
+        return modifications + linesToRemove.map { IAstModification.Remove(it, scope) }
+    }
+}

compiler/build.gradle

@@ -1,59 +1,57 @@
-buildscript {
-    dependencies {
-        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:1.3.72"
-    }
-}
-
 plugins {
-    // id "org.jetbrains.kotlin.jvm" version "1.3.72"
-    id 'application'
-    id 'org.jetbrains.dokka' version "0.9.18"
-    id 'com.github.johnrengelman.shadow' version '5.2.0'
     id 'java'
+    id 'application'
+    id "org.jetbrains.kotlin.jvm"
+    id 'com.github.johnrengelman.shadow' version '7.1.0'
+    id "io.kotest" version "0.3.8"
 }
 
-apply plugin: "kotlin"
-apply plugin: "java"
-
-targetCompatibility = 1.8
-sourceCompatibility = 1.8
-
-repositories {
-    mavenLocal()
-    mavenCentral()
-    jcenter()
-    maven { url "https://dl.bintray.com/orangy/maven/" }
-}
-
-def prog8version = rootProject.file('compiler/res/version.txt').text.trim()
-
-dependencies {
-    implementation project(':parser')
-    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8"
-    // implementation "org.jetbrains.kotlin:kotlin-reflect"
-    implementation 'org.antlr:antlr4-runtime:4.8'
-    implementation 'org.jetbrains.kotlinx:kotlinx-cli-jvm:0.1.0-dev-5'
-    // implementation 'net.razorvine:ksim65:1.6'
-    // implementation "com.github.hypfvieh:dbus-java:3.2.0"
-    implementation project(':parser')
-
-    testImplementation "org.jetbrains.kotlin:kotlin-test-junit5"
-    testImplementation 'org.junit.jupiter:junit-jupiter-api:5.3.2'
-    testImplementation 'org.hamcrest:hamcrest-junit:2.0.0.0'
-    testRuntimeOnly 'org.junit.jupiter:junit-jupiter-engine:5.3.2'
+java {
+    toolchain {
+        languageVersion = JavaLanguageVersion.of(javaVersion)
+    }
 }
 
 compileKotlin {
     kotlinOptions {
-        jvmTarget = "1.8"
-        // verbose = true
-        // freeCompilerArgs += "-XXLanguage:+NewInference"
+        jvmTarget = javaVersion
     }
 }
 
 compileTestKotlin {
     kotlinOptions {
-        jvmTarget = "1.8"
+        jvmTarget = javaVersion
+    }
+}
+
+def prog8version = rootProject.file('compiler/res/version.txt').text.trim()
+
+dependencies {
+    implementation project(':compilerInterfaces')
+    implementation project(':codeOptimizers')
+    implementation project(':compilerAst')
+    implementation project(':codeGenTargets')
+    implementation project(':codeGenCpu6502')
+    implementation project(':codeGenExperimental6502')
+    implementation 'org.antlr:antlr4-runtime:4.9.2'
+    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8"
+    // implementation "org.jetbrains.kotlin:kotlin-reflect"
+    implementation 'org.jetbrains.kotlinx:kotlinx-cli:0.3.3'
+    implementation "com.michael-bull.kotlin-result:kotlin-result-jvm:1.1.12"
+
+    testImplementation 'io.kotest:kotest-runner-junit5-jvm:4.6.3'
+}
+
+configurations.all {
+    exclude group: 'com.ibm.icu', module: 'icu4j'
+    exclude group: "org.antlr", module: "antlr4"
+}
+
+configurations {
+    // strange antlr plugin issue, see https://github.com/gradle/gradle/issues/820
+    // this avoids linking in the complete antlr binary jar
+    compile {
+        extendsFrom = extendsFrom.findAll { it != configurations.antlr }
     }
 }
 
@@ -68,7 +66,8 @@ sourceSets {
     }
     test {
         java {
-            srcDirs = ["${project.projectDir}/test"]
+            srcDir "${project.projectDir}/test"
+            srcDir "${project(':compilerAst').projectDir}/test/helpers"
         }
     }
 }
@@ -76,15 +75,10 @@ sourceSets {
 startScripts.enabled = true
 
 application {
-    mainClassName = 'prog8.CompilerMainKt'
+    mainClass = 'prog8.CompilerMainKt'
     applicationName = 'p8compile'
 }
 
-artifacts {
-    archives shadowJar
-}
-
-
 shadowJar {
     archiveBaseName = 'prog8compiler'
     archiveVersion = prog8version
@@ -105,8 +99,4 @@ test {
     }
 }
 
-
-dokka {
-    outputFormat = 'html'
-    outputDirectory = "$buildDir/kdoc"
-}
+build.finalizedBy installDist, installShadowDist

compiler/compiler.iml

@@ -8,12 +8,19 @@
       <sourceFolder url="file://$MODULE_DIR$/test" isTestSource="true" />
       <excludeFolder url="file://$MODULE_DIR$/build" />
     </content>
-    <orderEntry type="jdk" jdkName="openjdk-11" jdkType="JavaSDK" />
+    <orderEntry type="inheritedJdk" />
     <orderEntry type="sourceFolder" forTests="false" />
     <orderEntry type="library" name="KotlinJavaRuntime" level="project" />
-    <orderEntry type="module" module-name="parser" />
-    <orderEntry type="library" name="unittest-libs" level="project" />
-    <orderEntry type="library" name="kotlinx-cli-jvm-0.1.0-dev-5" level="project" />
-    <orderEntry type="library" name="antlr-runtime-4.8" level="project" />
+    <orderEntry type="module" module-name="compilerAst" />
+    <orderEntry type="library" name="jetbrains.kotlinx.cli.jvm" level="project" />
+    <orderEntry type="library" name="michael.bull.kotlin.result.jvm" level="project" />
+    <orderEntry type="module" module-name="codeOptimizers" />
+    <orderEntry type="module" module-name="compilerInterfaces" />
+    <orderEntry type="module" module-name="codeGenTargets" />
+    <orderEntry type="library" name="io.kotest.assertions.core.jvm" level="project" />
+    <orderEntry type="library" name="io.kotest.runner.junit5.jvm" level="project" />
+    <orderEntry type="library" name="antlr.antlr4" level="project" />
+    <orderEntry type="module" module-name="codeGenCpu6502" />
+    <orderEntry type="module" module-name="codeGenExperimental6502" />
   </component>
 </module>

compiler/res/.editorconfig

@@ -0,0 +1,20 @@
+root = true
+
+[*]
+charset = utf-8
+end_of_line = lf
+indent_size = 4
+indent_style = space
+insert_final_newline = true
+max_line_length = 120
+tab_width = 8
+trim_trailing_whitespace = true
+ij_smart_tabs = true
+
+[*.p8]
+indent_size = 4
+indent_style = space
+
+[*.asm]
+indent_size = 8
+indent_style = tab

compiler/res/prog8lib/atari/syslib.p8

@@ -0,0 +1,308 @@
+; Prog8 definitions for the Atari800XL
+; Including memory registers, I/O registers, Basic and Kernal subroutines.
+;
+; Written by Irmen de Jong (irmen@razorvine.net) - license: GNU GPL 3.0
+;
+
+atari {
+
+        &uword  NMI_VEC         = $FFFA     ; 6502 nmi vector, determined by the kernal if banked in
+        &uword  RESET_VEC       = $FFFC     ; 6502 reset vector, determined by the kernal if banked in
+        &uword  IRQ_VEC         = $FFFE     ; 6502 interrupt vector, determined by the kernal if banked in
+
+; ---- kernal routines ----
+; TODO
+
+
+asmsub  init_system()  {
+    ; Initializes the machine to a sane starting state.
+    ; Called automatically by the loader program logic.
+    ; TODO
+    %asm {{
+        sei
+        cld
+        clc
+        ; TODO reset screen mode etc etc
+        clv
+        cli
+        rts
+    }}
+}
+
+asmsub  init_system_phase2()  {
+    %asm {{
+        rts     ; no phase 2 steps on the Atari
+    }}
+}
+
+}
+
+
+sys {
+    ; ------- lowlevel system routines --------
+
+    const ubyte target = 8         ;  compilation target specifier.  64 = C64, 128 = C128,  16 = CommanderX16, 8 = atari800XL
+
+
+    asmsub  reset_system()  {
+        ; Soft-reset the system back to initial power-on Basic prompt.
+        ; TODO
+        %asm {{
+            sei
+            jmp  (atari.RESET_VEC)
+        }}
+    }
+
+    sub wait(uword jiffies) {
+        ; --- wait approximately the given number of jiffies (1/60th seconds)
+        ;     TODO
+    }
+
+    asmsub waitvsync() clobbers(A) {
+        ; --- busy wait till the next vsync has occurred (approximately), without depending on custom irq handling.
+        ;     TODO
+        %asm {{
+            nop
+            rts
+        }}
+    }
+
+    asmsub memcopy(uword source @R0, uword target @R1, uword count @AY) clobbers(A,X,Y) {
+        ; note: only works for NON-OVERLAPPING memory regions!
+        ; note: can't be inlined because is called from asm as well
+        %asm {{
+            ldx  cx16.r0
+            stx  P8ZP_SCRATCH_W1        ; source in ZP
+            ldx  cx16.r0+1
+            stx  P8ZP_SCRATCH_W1+1
+            ldx  cx16.r1
+            stx  P8ZP_SCRATCH_W2        ; target in ZP
+            ldx  cx16.r1+1
+            stx  P8ZP_SCRATCH_W2+1
+            cpy  #0
+            bne  _longcopy
+
+            ; copy <= 255 bytes
+            tay
+            bne  _copyshort
+            rts     ; nothing to copy
+
+_copyshort
+            ; decrease source and target pointers so we can simply index by Y
+            lda  P8ZP_SCRATCH_W1
+            bne  +
+            dec  P8ZP_SCRATCH_W1+1
++           dec  P8ZP_SCRATCH_W1
+            lda  P8ZP_SCRATCH_W2
+            bne  +
+            dec  P8ZP_SCRATCH_W2+1
++           dec  P8ZP_SCRATCH_W2
+
+-           lda  (P8ZP_SCRATCH_W1),y
+            sta  (P8ZP_SCRATCH_W2),y
+            dey
+            bne  -
+            rts
+
+_longcopy
+            sta  P8ZP_SCRATCH_B1        ; lsb(count) = remainder in last page
+            tya
+            tax                         ; x = num pages (1+)
+            ldy  #0
+-           lda  (P8ZP_SCRATCH_W1),y
+            sta  (P8ZP_SCRATCH_W2),y
+            iny
+            bne  -
+            inc  P8ZP_SCRATCH_W1+1
+            inc  P8ZP_SCRATCH_W2+1
+            dex
+            bne  -
+            ldy  P8ZP_SCRATCH_B1
+            bne  _copyshort
+            rts
+        }}
+    }
+
+    asmsub memset(uword mem @R0, uword numbytes @R1, ubyte value @A) clobbers(A,X,Y) {
+        %asm {{
+            ldy  cx16.r0
+            sty  P8ZP_SCRATCH_W1
+            ldy  cx16.r0+1
+            sty  P8ZP_SCRATCH_W1+1
+            ldx  cx16.r1
+            ldy  cx16.r1+1
+            jmp  prog8_lib.memset
+        }}
+    }
+
+    asmsub memsetw(uword mem @R0, uword numwords @R1, uword value @AY) clobbers(A,X,Y) {
+        %asm {{
+            ldx  cx16.r0
+            stx  P8ZP_SCRATCH_W1
+            ldx  cx16.r0+1
+            stx  P8ZP_SCRATCH_W1+1
+            ldx  cx16.r1
+            stx  P8ZP_SCRATCH_W2
+            ldx  cx16.r1+1
+            stx  P8ZP_SCRATCH_W2+1
+            jmp  prog8_lib.memsetw
+        }}
+    }
+
+    inline asmsub read_flags() -> ubyte @A {
+        %asm {{
+        php
+        pla
+        }}
+    }
+
+    inline asmsub clear_carry() {
+        %asm {{
+        clc
+        }}
+    }
+
+    inline asmsub set_carry() {
+        %asm {{
+        sec
+        }}
+    }
+
+    inline asmsub clear_irqd() {
+        %asm {{
+        cli
+        }}
+    }
+
+    inline asmsub set_irqd() {
+        %asm {{
+        sei
+        }}
+    }
+
+    inline asmsub exit(ubyte returnvalue @A) {
+        ; -- immediately exit the program with a return code in the A register
+        ;    TODO
+        %asm {{
+            ldx  prog8_lib.orig_stackpointer
+            txs
+            rts		; return to original caller
+        }}
+    }
+
+    inline asmsub progend() -> uword @AY {
+        %asm {{
+            lda  #<prog8_program_end
+            ldy  #>prog8_program_end
+        }}
+    }
+
+}
+
+cx16 {
+
+    ; the sixteen virtual 16-bit registers that the CX16 has defined in the zeropage
+    ; they are simulated on the Atari as well but their location in memory is different
+    ; TODO
+    &uword r0  = $1b00
+    &uword r1  = $1b02
+    &uword r2  = $1b04
+    &uword r3  = $1b06
+    &uword r4  = $1b08
+    &uword r5  = $1b0a
+    &uword r6  = $1b0c
+    &uword r7  = $1b0e
+    &uword r8  = $1b10
+    &uword r9  = $1b12
+    &uword r10 = $1b14
+    &uword r11 = $1b16
+    &uword r12 = $1b18
+    &uword r13 = $1b1a
+    &uword r14 = $1b1c
+    &uword r15 = $1b1e
+
+    &word r0s  = $1b00
+    &word r1s  = $1b02
+    &word r2s  = $1b04
+    &word r3s  = $1b06
+    &word r4s  = $1b08
+    &word r5s  = $1b0a
+    &word r6s  = $1b0c
+    &word r7s  = $1b0e
+    &word r8s  = $1b10
+    &word r9s  = $1b12
+    &word r10s = $1b14
+    &word r11s = $1b16
+    &word r12s = $1b18
+    &word r13s = $1b1a
+    &word r14s = $1b1c
+    &word r15s = $1b1e
+
+    &ubyte r0L  = $1b00
+    &ubyte r1L  = $1b02
+    &ubyte r2L  = $1b04
+    &ubyte r3L  = $1b06
+    &ubyte r4L  = $1b08
+    &ubyte r5L  = $1b0a
+    &ubyte r6L  = $1b0c
+    &ubyte r7L  = $1b0e
+    &ubyte r8L  = $1b10
+    &ubyte r9L  = $1b12
+    &ubyte r10L = $1b14
+    &ubyte r11L = $1b16
+    &ubyte r12L = $1b18
+    &ubyte r13L = $1b1a
+    &ubyte r14L = $1b1c
+    &ubyte r15L = $1b1e
+
+    &ubyte r0H  = $1b01
+    &ubyte r1H  = $1b03
+    &ubyte r2H  = $1b05
+    &ubyte r3H  = $1b07
+    &ubyte r4H  = $1b09
+    &ubyte r5H  = $1b0b
+    &ubyte r6H  = $1b0d
+    &ubyte r7H  = $1b0f
+    &ubyte r8H  = $1b11
+    &ubyte r9H  = $1b13
+    &ubyte r10H = $1b15
+    &ubyte r11H = $1b17
+    &ubyte r12H = $1b19
+    &ubyte r13H = $1b1b
+    &ubyte r14H = $1b1d
+    &ubyte r15H = $1b1f
+
+    &byte r0sL  = $1b00
+    &byte r1sL  = $1b02
+    &byte r2sL  = $1b04
+    &byte r3sL  = $1b06
+    &byte r4sL  = $1b08
+    &byte r5sL  = $1b0a
+    &byte r6sL  = $1b0c
+    &byte r7sL  = $1b0e
+    &byte r8sL  = $1b10
+    &byte r9sL  = $1b12
+    &byte r10sL = $1b14
+    &byte r11sL = $1b16
+    &byte r12sL = $1b18
+    &byte r13sL = $1b1a
+    &byte r14sL = $1b1c
+    &byte r15sL = $1b1e
+
+    &byte r0sH  = $1b01
+    &byte r1sH  = $1b03
+    &byte r2sH  = $1b05
+    &byte r3sH  = $1b07
+    &byte r4sH  = $1b09
+    &byte r5sH  = $1b0b
+    &byte r6sH  = $1b0d
+    &byte r7sH  = $1b0f
+    &byte r8sH  = $1b11
+    &byte r9sH  = $1b13
+    &byte r10sH = $1b15
+    &byte r11sH = $1b17
+    &byte r12sH = $1b19
+    &byte r13sH = $1b1b
+    &byte r14sH = $1b1d
+    &byte r15sH = $1b1f
+}

compiler/res/prog8lib/atari/textio.p8

@@ -0,0 +1,419 @@
+; Prog8 definitions for the Text I/O and Screen routines for the Atari 800XL
+;
+; Written by Irmen de Jong (irmen@razorvine.net) - license: GNU GPL 3.0
+
+%import syslib
+%import conv
+
+
+txt {
+
+const ubyte DEFAULT_WIDTH = 40
+const ubyte DEFAULT_HEIGHT = 24
+
+
+sub  clear_screen() {
+    txt.chrout(125)
+}
+
+sub nl() {
+    txt.chrout('\n')
+}
+
+sub spc() {
+    txt.chrout(' ')
+}
+
+asmsub column(ubyte col @A) clobbers(A, X, Y) {
+    ; ---- set the cursor on the given column (starting with 0) on the current line
+    ;      TODO
+    %asm {{
+        rts
+    }}
+}
+
+asmsub  fill_screen (ubyte char @ A, ubyte color @ Y) clobbers(A)  {
+    ; ---- fill the character screen with the given fill character and character color.
+    ;      (assumes screen and color matrix are at their default addresses)
+    ;      TODO
+
+    %asm {{
+        rts
+    }}
+}
+
+asmsub  clear_screenchars (ubyte char @ A) clobbers(Y)  {
+	; ---- clear the character screen with the given fill character (leaves colors)
+	;      (assumes screen matrix is at the default address)
+	; TODO
+	%asm {{
+	    rts
+	}}
+}
+
+asmsub  clear_screencolors (ubyte color @ A) clobbers(Y)  {
+	; ---- clear the character screen colors with the given color (leaves characters).
+	;      (assumes color matrix is at the default address)
+	; TODO
+	%asm {{
+	    rts
+        }}
+}
+
+sub color (ubyte txtcol) {
+    ; TODO
+}
+
+sub lowercase() {
+    ; TODO
+}
+
+sub uppercase() {
+    ; TODO
+}
+
+asmsub  scroll_left  (ubyte alsocolors @ Pc) clobbers(A, Y)  {
+	; ---- scroll the whole screen 1 character to the left
+	;      contents of the rightmost column are unchanged, you should clear/refill this yourself
+	;      Carry flag determines if screen color data must be scrolled too
+	;  TODO
+
+	%asm {{
+	    rts
+        }}
+}
+
+asmsub  scroll_right  (ubyte alsocolors @ Pc) clobbers(A)  {
+	; ---- scroll the whole screen 1 character to the right
+	;      contents of the leftmost column are unchanged, you should clear/refill this yourself
+	;      Carry flag determines if screen color data must be scrolled too
+	; TODO
+	%asm {{
+	    rts
+        }}
+}
+
+asmsub  scroll_up  (ubyte alsocolors @ Pc) clobbers(A)  {
+	; ---- scroll the whole screen 1 character up
+	;      contents of the bottom row are unchanged, you should refill/clear this yourself
+	;      Carry flag determines if screen color data must be scrolled too
+	; TODO
+	%asm {{
+	    rts
+        }}
+}
+
+asmsub  scroll_down  (ubyte alsocolors @ Pc) clobbers(A)  {
+	; ---- scroll the whole screen 1 character down
+	;      contents of the top row are unchanged, you should refill/clear this yourself
+	;      Carry flag determines if screen color data must be scrolled too
+	; TODO
+	%asm {{
+	    rts
+        }}
+}
+
+
+romsub $F2B0 = outchar(ubyte char @ A)
+romsub $F2Fd = waitkey()
+
+asmsub chrout(ubyte char @ A) {
+	%asm {{
+		sta  _tmp_outchar+1
+		pha
+		txa
+		pha
+		tya
+		pha
+_tmp_outchar
+		lda  #0
+		jsr  outchar
+		pla
+		tay
+		pla
+		tax
+		pla
+		rts
+	}}
+}
+
+asmsub  print (str text @ AY) clobbers(A,Y)  {
+	; ---- print null terminated string from A/Y
+	; note: the compiler contains an optimization that will replace
+	;       a call to this subroutine with a string argument of just one char,
+	;       by just one call to CHROUT of that single char.
+	%asm {{
+		sta  P8ZP_SCRATCH_B1
+		sty  P8ZP_SCRATCH_REG
+		ldy  #0
+-		lda  (P8ZP_SCRATCH_B1),y
+		beq  +
+		jsr  chrout
+		iny
+		bne  -
++		rts
+	}}
+}
+
+asmsub  print_ub0  (ubyte value @ A) clobbers(A,Y)  {
+	; ---- print the ubyte in A in decimal form, with left padding 0s (3 positions total)
+	%asm {{
+		stx  P8ZP_SCRATCH_REG
+		jsr  conv.ubyte2decimal
+		pha
+		tya
+		jsr  chrout
+		pla
+		jsr  chrout
+		txa
+		jsr  chrout
+		ldx  P8ZP_SCRATCH_REG
+		rts
+	}}
+}
+
+asmsub  print_ub  (ubyte value @ A) clobbers(A,Y)  {
+	; ---- print the ubyte in A in decimal form, without left padding 0s
+	%asm {{
+		stx  P8ZP_SCRATCH_REG
+		jsr  conv.ubyte2decimal
+_print_byte_digits
+		pha
+		cpy  #'0'
+		beq  +
+		tya
+		jsr  chrout
+		pla
+		jsr  chrout
+		jmp  _ones
++       pla
+        cmp  #'0'
+        beq  _ones
+        jsr  chrout
+_ones   txa
+		jsr  chrout
+		ldx  P8ZP_SCRATCH_REG
+		rts
+	}}
+}
+
+asmsub  print_b  (byte value @ A) clobbers(A,Y)  {
+	; ---- print the byte in A in decimal form, without left padding 0s
+	%asm {{
+		stx  P8ZP_SCRATCH_REG
+		pha
+		cmp  #0
+		bpl  +
+		lda  #'-'
+		jsr  chrout
++		pla
+		jsr  conv.byte2decimal
+		jmp  print_ub._print_byte_digits
+	}}
+}
+
+asmsub  print_ubhex  (ubyte value @ A, ubyte prefix @ Pc) clobbers(A,Y)  {
+	; ---- print the ubyte in A in hex form (if Carry is set, a radix prefix '$' is printed as well)
+	%asm {{
+		stx  P8ZP_SCRATCH_REG
+		bcc  +
+		pha
+		lda  #'$'
+		jsr  chrout
+		pla
++		jsr  conv.ubyte2hex
+		jsr  chrout
+		tya
+		jsr  chrout
+		ldx  P8ZP_SCRATCH_REG
+		rts
+	}}
+}
+
+asmsub  print_ubbin  (ubyte value @ A, ubyte prefix @ Pc) clobbers(A,Y)  {
+	; ---- print the ubyte in A in binary form (if Carry is set, a radix prefix '%' is printed as well)
+	%asm {{
+		stx  P8ZP_SCRATCH_REG
+		sta  P8ZP_SCRATCH_B1
+		bcc  +
+		lda  #'%'
+		jsr  chrout
++		ldy  #8
+-		lda  #'0'
+		asl  P8ZP_SCRATCH_B1
+		bcc  +
+		lda  #'1'
++		jsr  chrout
+		dey
+		bne  -
+		ldx  P8ZP_SCRATCH_REG
+		rts
+	}}
+}
+
+asmsub  print_uwbin  (uword value @ AY, ubyte prefix @ Pc) clobbers(A,Y)  {
+	; ---- print the uword in A/Y in binary form (if Carry is set, a radix prefix '%' is printed as well)
+	%asm {{
+		pha
+		tya
+		jsr  print_ubbin
+		pla
+		clc
+		jmp  print_ubbin
+	}}
+}
+
+asmsub  print_uwhex  (uword value @ AY, ubyte prefix @ Pc) clobbers(A,Y)  {
+	; ---- print the uword in A/Y in hexadecimal form (4 digits)
+	;      (if Carry is set, a radix prefix '$' is printed as well)
+	%asm {{
+		pha
+		tya
+		jsr  print_ubhex
+		pla
+		clc
+		jmp  print_ubhex
+	}}
+}
+
+asmsub  print_uw0  (uword value @ AY) clobbers(A,Y)  {
+	; ---- print the uword in A/Y in decimal form, with left padding 0s (5 positions total)
+	%asm {{
+	    stx  P8ZP_SCRATCH_REG
+		jsr  conv.uword2decimal
+		ldy  #0
+-		lda  conv.uword2decimal.decTenThousands,y
+        beq  +
+		jsr  chrout
+		iny
+		bne  -
++		ldx  P8ZP_SCRATCH_REG
+		rts
+	}}
+}
+
+asmsub  print_uw  (uword value @ AY) clobbers(A,Y)  {
+	; ---- print the uword in A/Y in decimal form, without left padding 0s
+	%asm {{
+	    stx  P8ZP_SCRATCH_REG
+		jsr  conv.uword2decimal
+		ldx  P8ZP_SCRATCH_REG
+		ldy  #0
+-		lda  conv.uword2decimal.decTenThousands,y
+		beq  _allzero
+		cmp  #'0'
+		bne  _gotdigit
+		iny
+		bne  -
+
+_gotdigit
+		jsr  chrout
+		iny
+		lda  conv.uword2decimal.decTenThousands,y
+		bne  _gotdigit
+		rts
+_allzero
+        lda  #'0'
+        jmp  chrout
+	}}
+}
+
+asmsub  print_w  (word value @ AY) clobbers(A,Y)  {
+	; ---- print the (signed) word in A/Y in decimal form, without left padding 0's
+	%asm {{
+		cpy  #0
+		bpl  +
+		pha
+		lda  #'-'
+		jsr  chrout
+		tya
+		eor  #255
+		tay
+		pla
+		eor  #255
+		clc
+		adc  #1
+		bcc  +
+		iny
++		jmp  print_uw
+	}}
+}
+
+asmsub  input_chars  (uword buffer @ AY) clobbers(A) -> ubyte @ Y  {
+	; ---- Input a string (max. 80 chars) from the keyboard. Returns length in Y. (string is terminated with a 0 byte as well)
+	;      It assumes the keyboard is selected as I/O channel!
+	;  TODO
+
+	%asm {{
+	    ldy  #0
+	    rts
+	}}
+}
+
+asmsub  setchr  (ubyte col @X, ubyte row @Y, ubyte character @A) clobbers(A, Y)  {
+	; ---- sets the character in the screen matrix at the given position
+	; TODO
+	%asm {{
+        	rts
+        }}
+}
+
+asmsub  getchr  (ubyte col @A, ubyte row @Y) clobbers(Y) -> ubyte @ A {
+	; ---- get the character in the screen matrix at the given location
+	; TODO
+	%asm {{
+        	rts
+        }}
+}
+
+asmsub  setclr  (ubyte col @X, ubyte row @Y, ubyte color @A) clobbers(A, Y)  {
+	; ---- set the color in A on the screen matrix at the given position
+	; TODO
+	%asm {{
+        	rts
+        }}
+}
+
+asmsub  getclr  (ubyte col @A, ubyte row @Y) clobbers(Y) -> ubyte @ A {
+	; ---- get the color in the screen color matrix at the given location
+	; TODO
+	%asm {{
+        	rts
+        }}
+}
+
+sub  setcc  (ubyte column, ubyte row, ubyte char, ubyte charcolor)  {
+	; ---- set char+color at the given position on the screen
+	; TODO
+	%asm {{
+        	rts
+        }}
+}
+
+asmsub  plot  (ubyte col @ Y, ubyte row @ A) clobbers(A) {
+	; ---- set cursor at specific position
+	; TODO
+	%asm  {{
+	    rts
+	}}
+}
+
+asmsub width() clobbers(X,Y) -> ubyte @A {
+    ; -- returns the text screen width (number of columns)
+    ; TODO
+    %asm {{
+        lda  #0
+        rts
+    }}
+}
+
+asmsub height() clobbers(X, Y) -> ubyte @A {
+    ; -- returns the text screen height (number of rows)
+    ; TODO
+    %asm {{
+        lda  #0
+        rts
+    }}
+}
+
+}

compiler/res/prog8lib/c128/floats.asm

@@ -0,0 +1,683 @@
+; --- low level floating point assembly routines for the C128
+;     these are almost all identical to the C64 except for a few details
+;     so we have to have a separate library file for the C128 unfortunately.
+
+
+FL_ONE_const	.byte  129     			; 1.0
+FL_ZERO_const	.byte  0,0,0,0,0		; 0.0
+FL_LOG2_const	.byte  $80, $31, $72, $17, $f8	; log(2)
+
+
+floats_store_reg	.byte  0		; temp storage
+
+
+ub2float	.proc
+		; -- convert ubyte in SCRATCH_ZPB1 to float at address A/Y
+		;    clobbers A, Y
+		stx  P8ZP_SCRATCH_REG
+		sta  P8ZP_SCRATCH_W2
+		sty  P8ZP_SCRATCH_W2+1
+		ldy  P8ZP_SCRATCH_B1
+		lda  #0
+		jsr  GIVAYF
+_fac_to_mem	ldx  P8ZP_SCRATCH_W2
+		ldy  P8ZP_SCRATCH_W2+1
+		jsr  MOVMF
+		ldx  P8ZP_SCRATCH_REG
+		rts
+		.pend
+
+b2float		.proc
+		; -- convert byte in SCRATCH_ZPB1 to float at address A/Y
+		;    clobbers A, Y
+		stx  P8ZP_SCRATCH_REG
+		sta  P8ZP_SCRATCH_W2
+		sty  P8ZP_SCRATCH_W2+1
+		lda  P8ZP_SCRATCH_B1
+		jsr  FREADSA
+		jmp  ub2float._fac_to_mem
+		.pend
+
+uw2float	.proc
+		; -- convert uword in SCRATCH_ZPWORD1 to float at address A/Y
+		stx  P8ZP_SCRATCH_REG
+		sta  P8ZP_SCRATCH_W2
+		sty  P8ZP_SCRATCH_W2+1
+		lda  P8ZP_SCRATCH_W1
+		ldy  P8ZP_SCRATCH_W1+1
+		jsr  GIVUAYFAY
+		jmp  ub2float._fac_to_mem
+		.pend
+
+w2float		.proc
+		; -- convert word in SCRATCH_ZPWORD1 to float at address A/Y
+		stx  P8ZP_SCRATCH_REG
+		sta  P8ZP_SCRATCH_W2
+		sty  P8ZP_SCRATCH_W2+1
+		ldy  P8ZP_SCRATCH_W1
+		lda  P8ZP_SCRATCH_W1+1
+		jsr  GIVAYF
+		jmp  ub2float._fac_to_mem
+		.pend
+
+
+cast_from_uw	.proc
+		; -- uword in A/Y into float var at (P8ZP_SCRATCH_W2)
+		stx  P8ZP_SCRATCH_REG
+		jsr  GIVUAYFAY
+		jmp  ub2float._fac_to_mem
+		.pend
+
+
+cast_from_w	.proc
+		; -- word in A/Y into float var at (P8ZP_SCRATCH_W2)
+		stx  P8ZP_SCRATCH_REG
+		jsr  GIVAYFAY
+		jmp  ub2float._fac_to_mem
+		.pend
+
+
+cast_from_ub	.proc
+		; -- ubyte in Y into float var at (P8ZP_SCRATCH_W2)
+		stx  P8ZP_SCRATCH_REG
+		jsr  FREADUY
+		jmp  ub2float._fac_to_mem
+		.pend
+
+
+cast_from_b	.proc
+		; -- byte in A into float var at (P8ZP_SCRATCH_W2)
+		stx  P8ZP_SCRATCH_REG
+		jsr  FREADSA
+		jmp  ub2float._fac_to_mem
+		.pend
+
+cast_as_uw_into_ya	.proc               ; also used for float 2 ub
+		; -- cast float at A/Y to uword into Y/A
+		jsr  MOVFM
+		jmp  cast_FAC1_as_uw_into_ya
+		.pend
+
+cast_as_w_into_ay	.proc               ; also used for float 2 b
+		; -- cast float at A/Y to word into A/Y
+		jsr  MOVFM
+		jmp  cast_FAC1_as_w_into_ay
+		.pend
+
+cast_FAC1_as_uw_into_ya	.proc               ; also used for float 2 ub
+		; -- cast fac1 to uword into Y/A
+		stx  P8ZP_SCRATCH_REG
+		jsr  GETADR     ; into Y/A
+		ldx  P8ZP_SCRATCH_REG
+		rts
+		.pend
+
+cast_FAC1_as_w_into_ay	.proc               ; also used for float 2 b
+		; -- cast fac1 to word into A/Y
+		stx  P8ZP_SCRATCH_REG
+		jsr  AYINT
+		ldy  $66
+		lda  $67
+		ldx  P8ZP_SCRATCH_REG
+		rts
+		.pend
+
+
+stack_b2float	.proc
+		; -- b2float operating on the stack
+		inx
+		lda  P8ESTACK_LO,x
+		stx  P8ZP_SCRATCH_REG
+		jsr  FREADSA
+		jmp  push_fac1._internal
+		.pend
+
+stack_w2float	.proc
+		; -- w2float operating on the stack
+		inx
+		ldy  P8ESTACK_LO,x
+		lda  P8ESTACK_HI,x
+		stx  P8ZP_SCRATCH_REG
+		jsr  GIVAYF
+		jmp  push_fac1._internal
+		.pend
+
+stack_ub2float	.proc
+		; -- ub2float operating on the stack
+		inx
+		lda  P8ESTACK_LO,x
+		stx  P8ZP_SCRATCH_REG
+		tay
+		lda  #0
+		jsr  GIVAYF
+		jmp  push_fac1._internal
+		.pend
+
+stack_uw2float	.proc
+		; -- uw2float operating on the stack
+		inx
+		lda  P8ESTACK_LO,x
+		ldy  P8ESTACK_HI,x
+		stx  P8ZP_SCRATCH_REG
+		jsr  GIVUAYFAY
+		jmp  push_fac1._internal
+		.pend
+
+stack_float2w	.proc               ; also used for float2b
+		jsr  pop_float_fac1
+		stx  P8ZP_SCRATCH_REG
+		jsr  AYINT
+		ldx  P8ZP_SCRATCH_REG
+		lda  $66
+		sta  P8ESTACK_HI,x
+		lda  $67
+		sta  P8ESTACK_LO,x
+		dex
+		rts
+		.pend
+
+stack_float2uw	.proc               ; also used for float2ub
+		jsr  pop_float_fac1
+		stx  P8ZP_SCRATCH_REG
+		jsr  GETADR
+		ldx  P8ZP_SCRATCH_REG
+		sta  P8ESTACK_HI,x
+		tya
+		sta  P8ESTACK_LO,x
+		dex
+		rts
+		.pend
+
+push_float	.proc
+		; ---- push mflpt5 in A/Y onto stack
+		; (taking 3 stack positions = 6 bytes of which 1 is padding)
+		sta  P8ZP_SCRATCH_W1
+		sty  P8ZP_SCRATCH_W1+1
+		ldy  #0
+		lda  (P8ZP_SCRATCH_W1),y
+		sta  P8ESTACK_LO,x
+		iny
+		lda  (P8ZP_SCRATCH_W1),y
+		sta  P8ESTACK_HI,x
+		dex
+		iny
+		lda  (P8ZP_SCRATCH_W1),y
+		sta  P8ESTACK_LO,x
+		iny
+		lda  (P8ZP_SCRATCH_W1),y
+		sta  P8ESTACK_HI,x
+		dex
+		iny
+		lda  (P8ZP_SCRATCH_W1),y
+		sta  P8ESTACK_LO,x
+		dex
+		rts
+		.pend
+
+pop_float	.proc
+		; ---- pops mflpt5 from stack to memory A/Y
+		; (frees 3 stack positions = 6 bytes of which 1 is padding)
+		sta  P8ZP_SCRATCH_W1
+		sty  P8ZP_SCRATCH_W1+1
+		ldy  #4
+		inx
+		lda  P8ESTACK_LO,x
+		sta  (P8ZP_SCRATCH_W1),y
+		dey
+		inx
+		lda  P8ESTACK_HI,x
+		sta  (P8ZP_SCRATCH_W1),y
+		dey
+		lda  P8ESTACK_LO,x
+		sta  (P8ZP_SCRATCH_W1),y
+		dey
+		inx
+		lda  P8ESTACK_HI,x
+		sta  (P8ZP_SCRATCH_W1),y
+		dey
+		lda  P8ESTACK_LO,x
+		sta  (P8ZP_SCRATCH_W1),y
+		rts
+		.pend
+
+pop_float_fac1	.proc
+		; -- pops float from stack into FAC1
+		lda  #<fmath_float1
+		ldy  #>fmath_float1
+		jsr  pop_float
+		lda  #<fmath_float1
+		ldy  #>fmath_float1
+		jmp  MOVFM
+		.pend
+
+copy_float	.proc
+		; -- copies the 5 bytes of the mflt value pointed to by SCRATCH_ZPWORD1,
+		;    into the 5 bytes pointed to by A/Y.  Clobbers A,Y.
+		sta  _target+1
+		sty  _target+2
+		ldy  #4
+_loop		lda  (P8ZP_SCRATCH_W1),y
+_target		sta  $ffff,y			; modified
+		dey
+		bpl  _loop
+		rts
+		.pend
+
+inc_var_f	.proc
+		; -- add 1 to float pointed to by A/Y
+		sta  P8ZP_SCRATCH_W1
+		sty  P8ZP_SCRATCH_W1+1
+		stx  P8ZP_SCRATCH_REG
+		jsr  MOVFM
+		lda  #<FL_ONE_const
+		ldy  #>FL_ONE_const
+		jsr  FADD
+		ldx  P8ZP_SCRATCH_W1
+		ldy  P8ZP_SCRATCH_W1+1
+		jsr  MOVMF
+		ldx  P8ZP_SCRATCH_REG
+		rts
+		.pend
+
+dec_var_f	.proc
+		; -- subtract 1 from float pointed to by A/Y
+		sta  P8ZP_SCRATCH_W1
+		sty  P8ZP_SCRATCH_W1+1
+		stx  P8ZP_SCRATCH_REG
+		lda  #<FL_ONE_const
+		ldy  #>FL_ONE_const
+		jsr  MOVFM
+		lda  P8ZP_SCRATCH_W1
+		ldy  P8ZP_SCRATCH_W1+1
+		jsr  FSUB
+		ldx  P8ZP_SCRATCH_W1
+		ldy  P8ZP_SCRATCH_W1+1
+		jsr  MOVMF
+		ldx  P8ZP_SCRATCH_REG
+		rts
+		.pend
+
+
+pop_2_floats_f2_in_fac1	.proc
+		; -- pop 2 floats from stack, load the second one in FAC1 as well
+		lda  #<fmath_float2
+		ldy  #>fmath_float2
+		jsr  pop_float
+		lda  #<fmath_float1
+		ldy  #>fmath_float1
+		jsr  pop_float
+		lda  #<fmath_float2
+		ldy  #>fmath_float2
+		jmp  MOVFM
+		.pend
+
+
+fmath_float1	.byte 0,0,0,0,0	; storage for a mflpt5 value
+fmath_float2	.byte 0,0,0,0,0	; storage for a mflpt5 value
+
+
+push_fac1	.proc
+		; -- push the float in FAC1 onto the stack
+		stx  P8ZP_SCRATCH_REG
+_internal	ldx  #<fmath_float1
+		ldy  #>fmath_float1
+		jsr  MOVMF
+		lda  #<fmath_float1
+		ldy  #>fmath_float1
+		ldx  P8ZP_SCRATCH_REG
+		jmp  push_float
+		.pend
+
+
+pow_f		.proc
+		; -- push f1 ** f2 on stack
+		lda  #<fmath_float2
+		ldy  #>fmath_float2
+		jsr  pop_float
+		lda  #<fmath_float1
+		ldy  #>fmath_float1
+		jsr  pop_float
+		stx  P8ZP_SCRATCH_REG
+		lda  #<fmath_float1
+		ldy  #>fmath_float1
+		jsr  ROMUPK		; fac2 = float1
+		lda  #<fmath_float2
+		ldy  #>fmath_float2
+		jsr  FPWR
+		jmp  push_fac1._internal
+		.pend
+
+div_f		.proc
+		; -- push f1/f2 on stack
+		jsr  pop_2_floats_f2_in_fac1
+		stx  P8ZP_SCRATCH_REG
+		lda  #<fmath_float1
+		ldy  #>fmath_float1
+		jsr  FDIV
+		jmp  push_fac1._internal
+		.pend
+
+add_f		.proc
+		; -- push f1+f2 on stack
+		jsr  pop_2_floats_f2_in_fac1
+		stx  P8ZP_SCRATCH_REG
+		lda  #<fmath_float1
+		ldy  #>fmath_float1
+		jsr  FADD
+		jmp  push_fac1._internal
+		.pend
+
+sub_f		.proc
+		; -- push f1-f2 on stack
+		jsr  pop_2_floats_f2_in_fac1
+		stx  P8ZP_SCRATCH_REG
+		lda  #<fmath_float1
+		ldy  #>fmath_float1
+		jsr  FSUB
+		jmp  push_fac1._internal
+		.pend
+
+mul_f		.proc
+		; -- push f1*f2 on stack
+		jsr  pop_2_floats_f2_in_fac1
+		stx  P8ZP_SCRATCH_REG
+		lda  #<fmath_float1
+		ldy  #>fmath_float1
+		jsr  FMULT
+		jmp  push_fac1._internal
+		.pend
+
+neg_f		.proc
+		; -- toggle the sign bit on the stack
+		lda  P8ESTACK_HI+3,x
+		eor  #$80
+		sta  P8ESTACK_HI+3,x
+		rts
+		.pend
+
+var_fac1_less_f	.proc
+		; -- is the float in FAC1 < the variable AY?
+		stx  P8ZP_SCRATCH_REG
+		jsr  FCOMP
+		ldx  P8ZP_SCRATCH_REG
+		cmp  #255
+		beq  +
+		lda  #0
+		rts
++		lda  #1
+		rts
+		.pend
+
+var_fac1_lesseq_f	.proc
+		; -- is the float in FAC1 <= the variable AY?
+		stx  P8ZP_SCRATCH_REG
+		jsr  FCOMP
+		ldx  P8ZP_SCRATCH_REG
+		cmp  #0
+		beq  +
+		cmp  #255
+		beq  +
+		lda  #0
+		rts
++		lda  #1
+		rts
+		.pend
+
+var_fac1_greater_f	.proc
+		; -- is the float in FAC1 > the variable AY?
+		stx  P8ZP_SCRATCH_REG
+		jsr  FCOMP
+		ldx  P8ZP_SCRATCH_REG
+		cmp  #1
+		beq  +
+		lda  #0
+		rts
++		lda  #1
+		rts
+		.pend
+
+var_fac1_greatereq_f	.proc
+		; -- is the float in FAC1 >= the variable AY?
+		stx  P8ZP_SCRATCH_REG
+		jsr  FCOMP
+		ldx  P8ZP_SCRATCH_REG
+		cmp  #0
+		beq  +
+		cmp  #1
+		beq  +
+		lda  #0
+		rts
++		lda  #1
+		rts
+		.pend
+
+var_fac1_notequal_f	.proc
+		; -- are the floats numbers in FAC1 and the variable AY *not* identical?
+		stx  P8ZP_SCRATCH_REG
+		jsr  FCOMP
+		ldx  P8ZP_SCRATCH_REG
+		and  #1
+		rts
+		.pend
+
+vars_equal_f	.proc
+		; -- are the mflpt5 numbers in P8ZP_SCRATCH_W1 and AY identical?
+		sta  P8ZP_SCRATCH_W2
+		sty  P8ZP_SCRATCH_W2+1
+		ldy  #0
+		lda  (P8ZP_SCRATCH_W1),y
+		cmp  (P8ZP_SCRATCH_W2),y
+		bne  _false
+		iny
+		lda  (P8ZP_SCRATCH_W1),y
+		cmp  (P8ZP_SCRATCH_W2),y
+		bne  _false
+		iny
+		lda  (P8ZP_SCRATCH_W1),y
+		cmp  (P8ZP_SCRATCH_W2),y
+		bne  _false
+		iny
+		lda  (P8ZP_SCRATCH_W1),y
+		cmp  (P8ZP_SCRATCH_W2),y
+		bne  _false
+		iny
+		lda  (P8ZP_SCRATCH_W1),y
+		cmp  (P8ZP_SCRATCH_W2),y
+		bne  _false
+		lda  #1
+		rts
+_false		lda  #0
+		rts
+		.pend
+
+equal_f		.proc
+		; -- are the two mflpt5 numbers on the stack identical?
+		inx
+		inx
+		inx
+		inx
+		lda  P8ESTACK_LO-3,x
+		cmp  P8ESTACK_LO,x
+		bne  _equals_false
+		lda  P8ESTACK_LO-2,x
+		cmp  P8ESTACK_LO+1,x
+		bne  _equals_false
+		lda  P8ESTACK_LO-1,x
+		cmp  P8ESTACK_LO+2,x
+		bne  _equals_false
+		lda  P8ESTACK_HI-2,x
+		cmp  P8ESTACK_HI+1,x
+		bne  _equals_false
+		lda  P8ESTACK_HI-1,x
+		cmp  P8ESTACK_HI+2,x
+		bne  _equals_false
+_equals_true	lda  #1
+_equals_store	inx
+		sta  P8ESTACK_LO+1,x
+		rts
+_equals_false	lda  #0
+		beq  _equals_store
+		.pend
+
+notequal_f	.proc
+		; -- are the two mflpt5 numbers on the stack different?
+		jsr  equal_f
+		eor  #1		; invert the result
+		sta  P8ESTACK_LO+1,x
+		rts
+		.pend
+
+vars_less_f	.proc
+		; -- is float in AY < float in P8ZP_SCRATCH_W2 ?
+		jsr  MOVFM
+		lda  P8ZP_SCRATCH_W2
+		ldy  P8ZP_SCRATCH_W2+1
+		stx  P8ZP_SCRATCH_REG
+		jsr  FCOMP
+		ldx  P8ZP_SCRATCH_REG
+		cmp  #255
+		bne  +
+		lda  #1
+		rts
++		lda  #0
+		rts
+		.pend
+
+vars_lesseq_f	.proc
+		; -- is float in AY <= float in P8ZP_SCRATCH_W2 ?
+		jsr  MOVFM
+		lda  P8ZP_SCRATCH_W2
+		ldy  P8ZP_SCRATCH_W2+1
+		stx  P8ZP_SCRATCH_REG
+		jsr  FCOMP
+		ldx  P8ZP_SCRATCH_REG
+		cmp  #255
+		bne  +
+-		lda  #1
+		rts
++		cmp  #0
+		beq  -
+		lda  #0
+		rts
+		.pend
+
+less_f		.proc
+		; -- is f1 < f2?
+		jsr  compare_floats
+		cmp  #255
+		beq  compare_floats._return_true
+		bne  compare_floats._return_false
+		.pend
+
+
+lesseq_f	.proc
+		; -- is f1 <= f2?
+		jsr  compare_floats
+		cmp  #255
+		beq  compare_floats._return_true
+		cmp  #0
+		beq  compare_floats._return_true
+		bne  compare_floats._return_false
+		.pend
+
+greater_f	.proc
+		; -- is f1 > f2?
+		jsr  compare_floats
+		cmp  #1
+		beq  compare_floats._return_true
+		bne  compare_floats._return_false
+		.pend
+
+greatereq_f	.proc
+		; -- is f1 >= f2?
+		jsr  compare_floats
+		cmp  #1
+		beq  compare_floats._return_true
+		cmp  #0
+		beq  compare_floats._return_true
+		bne  compare_floats._return_false
+		.pend
+
+compare_floats	.proc
+		lda  #<fmath_float2
+		ldy  #>fmath_float2
+		jsr  pop_float
+		lda  #<fmath_float1
+		ldy  #>fmath_float1
+		jsr  pop_float
+		lda  #<fmath_float1
+		ldy  #>fmath_float1
+		jsr  MOVFM		; fac1 = flt1
+		lda  #<fmath_float2
+		ldy  #>fmath_float2
+		stx  P8ZP_SCRATCH_REG
+		jsr  FCOMP		; A = flt1 compared with flt2 (0=equal, 1=flt1>flt2, 255=flt1<flt2)
+		ldx  P8ZP_SCRATCH_REG
+		rts
+_return_false	lda  #0
+_return_result  sta  P8ESTACK_LO,x
+		dex
+		rts
+_return_true	lda  #1
+		bne  _return_result
+		.pend
+
+set_array_float_from_fac1	.proc
+		; -- set the float in FAC1 in the array (index in A, array in P8ZP_SCRATCH_W1)
+		sta  P8ZP_SCRATCH_B1
+		asl  a
+		asl  a
+		clc
+		adc  P8ZP_SCRATCH_B1
+		ldy  P8ZP_SCRATCH_W1+1
+		clc
+		adc  P8ZP_SCRATCH_W1
+		bcc  +
+		iny
++		stx  floats_store_reg
+		tax
+		jsr  MOVMF
+		ldx  floats_store_reg
+		rts
+		.pend
+
+
+set_0_array_float	.proc
+		; -- set a float in an array to zero (index in A, array in P8ZP_SCRATCH_W1)
+		sta  P8ZP_SCRATCH_B1
+		asl  a
+		asl  a
+		clc
+		adc  P8ZP_SCRATCH_B1
+		tay
+		lda  #0
+		sta  (P8ZP_SCRATCH_W1),y
+		iny
+		sta  (P8ZP_SCRATCH_W1),y
+		iny
+		sta  (P8ZP_SCRATCH_W1),y
+		iny
+		sta  (P8ZP_SCRATCH_W1),y
+		iny
+		sta  (P8ZP_SCRATCH_W1),y
+		rts
+		.pend
+
+
+set_array_float		.proc
+		; -- set a float in an array to a value (index in A, float in P8ZP_SCRATCH_W1, array in P8ZP_SCRATCH_W2)
+		sta  P8ZP_SCRATCH_B1
+		asl  a
+		asl  a
+		clc
+		adc  P8ZP_SCRATCH_B1
+		adc  P8ZP_SCRATCH_W2
+		ldy  P8ZP_SCRATCH_W2+1
+		bcc  +
+		iny
++		jmp  copy_float
+			; -- copies the 5 bytes of the mflt value pointed to by SCRATCH_ZPWORD1,
+			;    into the 5 bytes pointed to by A/Y.  Clobbers A,Y.
+		.pend
+
+

compiler/res/prog8lib/c128/floats.p8

@@ -0,0 +1,157 @@
+; Prog8 definitions for floating point handling on the Commodore 128
+;
+; Written by Irmen de Jong (irmen@razorvine.net) - license: GNU GPL 3.0
+
+%option enable_floats
+
+floats {
+	; ---- this block contains C-128 compatible floating point related functions ----
+
+        const float  PI     = 3.141592653589793
+        const float  TWOPI  = 6.283185307179586
+
+
+; ---- ROM float functions ----
+
+		; note: the fac1 and fac2 are working registers and take 6 bytes each,
+		; floats in memory  (and rom) are stored in 5-byte MFLPT packed format.
+
+; note: fac1/2 might get clobbered even if not mentioned in the function's name.
+; note: for subtraction and division, the left operand is in fac2, the right operand in fac1.
+
+romsub $af00 = AYINT() clobbers(A,X,Y)          ; fac1-> signed word in 102-103 ($66-$67) MSB FIRST. (might throw ILLEGAL QUANTITY)
+
+; GIVAYF: signed word in Y/A (note different lsb/msb order) -> float in fac1
+; there is also floats.GIVUAYFAY - unsigned word in A/Y (lo/hi) to fac1
+; (tip: use GIVAYFAY to use A/Y input; lo/hi switched to normal order)
+romsub $af03 = GIVAYF(ubyte lo @ Y, ubyte hi @ A) clobbers(A,X,Y)
+romsub $af09 = VAL(ubyte length @ A) clobbers(A,X,Y)       ; str -> fac1, $24/25 must point to string in bank1, A=string length   Don't call this from bank0
+
+; fac1 -> unsigned word in Y/A (might throw ILLEGAL QUANTITY) (result also in $16/17)
+; (tip: use GETADRAY to get A/Y output; lo/hi switched to normal little endian order)
+romsub $af0c = GETADR() clobbers(X) -> ubyte @ Y, ubyte @ A
+
+romsub $af12 = FSUB(uword mflpt @ AY) clobbers(A,X,Y)       ; fac1 = mflpt from A/Y - fac1
+romsub $af15 = FSUBT() clobbers(A,X,Y)                      ; fac1 = fac2-fac1   mind the order of the operands
+romsub $af18 = FADD(uword mflpt @ AY) clobbers(A,X,Y)       ; fac1 += mflpt value from A/Y in bank 1
+romsub $af1b = FADDT() clobbers(A,X,Y)                      ; fac1 += fac2
+romsub $af2a = LOG() clobbers(A,X,Y)                        ; fac1 = LN(fac1)  (natural log)
+romsub $af1e = FMULT(uword mflpt @ AY) clobbers(A,X,Y)      ; fac1 *= mflpt value from A/Y
+romsub $af21 = FMULTT() clobbers(A,X,Y)                     ; fac1 *= fac2
+romsub $af5a = CONUPK(uword mflpt @ AY) clobbers(A,X,Y)     ; load mflpt value from memory bank 1  in A/Y into fac2
+romsub $af5d = ROMUPK(uword mflpt @ AY) clobbers(A,X,Y)     ; load mflpt value from memory in current bank in A/Y into fac2
+romsub $af24 = FDIV(uword mflpt @ AY) clobbers(A,X,Y)       ; fac1 = mflpt in A/Y / fac1  (remainder in fac2)
+romsub $af27 = FDIVT() clobbers(A,X,Y)                      ; fac1 = fac2/fac1  (remainder in fac2)  mind the order of the operands
+
+romsub $af63 = MOVFM(uword mflpt @ AY) clobbers(A,X,Y)      ; load mflpt value from memory  in A/Y into fac1
+romsub $af60 = MOVFRM() clobbers(A,X,Y)                     ; load mflpt value from memory  in $24/$25 into fac2
+romsub $af66 = MOVMF(uword mflpt @ XY) clobbers(A,X,Y)      ; store fac1 to memory  X/Y as 5-byte mflpt
+romsub $af69 = MOVFA() clobbers(A,X)                        ; copy fac2 to fac1
+romsub $af6c = MOVAF() clobbers(A,X)                        ; copy fac1 to fac2
+romsub $af6c = MOVEF() clobbers(A,X)                        ; copy fac1 to fac2
+romsub $af51 = SIGN() clobbers(X,Y) -> ubyte @ A            ; SIGN(fac1) to A, $ff, $0, $1 for negative, zero, positive
+romsub $af4e = ABS() clobbers(A,X,Y)                        ; fac1 = ABS(fac1)
+romsub $af54 = FCOMP(uword mflpt @ AY) clobbers(X,Y) -> ubyte @ A   ; A = compare fac1 to mflpt in A/Y, 0=equal 1=fac1 is greater, 255=fac1 is less than
+romsub $af2d = INT() clobbers(A,X,Y)                        ; INT() truncates, use FADDH first to round instead of trunc
+romsub $af06 = FOUT() clobbers(X) -> uword @ AY             ; fac1 -> string, address returned in AY ($0100)
+romsub $af30 = SQR() clobbers(A,X,Y)                        ; fac1 = SQRT(fac1)
+romsub $af36 = FPWR(uword mflpt @ AY) clobbers(A,X,Y)       ; fac1 = fac2 ** mflpt from A/Y
+romsub $af39 = FPWRT() clobbers(A,X,Y)                      ; fac1 = fac2 ** fac1
+romsub $af33 = NEGOP() clobbers(A)                          ; switch the sign of fac1 (fac1 = -fac1)
+romsub $af3c = EXP() clobbers(A,X,Y)                        ; fac1 = EXP(fac1)  (e ** fac1)
+romsub $af57 = RND() clobbers(A,X,Y)                        ; fac1 = RND(fac1) float random number generator
+romsub $af3f = COS() clobbers(A,X,Y)                        ; fac1 = COS(fac1)
+romsub $af42 = SIN() clobbers(A,X,Y)                        ; fac1 = SIN(fac1)
+romsub $af45 = TAN() clobbers(A,X,Y)                        ; fac1 = TAN(fac1)
+romsub $af48 = ATN() clobbers(A,X,Y)                        ; fac1 = ATN(fac1)
+
+
+asmsub  FREADSA  (byte value @A) clobbers(A,X,Y) {
+    ; ---- 8 bit signed A -> float in fac1
+    %asm {{
+        tay
+        bpl  +
+        lda  #$ff
+        jmp  GIVAYF
++       lda  #0
+        jmp  GIVAYF
+    }}
+}
+
+asmsub  GIVUAYFAY  (uword value @ AY) clobbers(A,X,Y)  {
+	; ---- unsigned 16 bit word in A/Y (lo/hi) to fac1
+	%asm {{
+            stx  P8ZP_SCRATCH_REG
+            sta  _tmp
+            sty  P8ZP_SCRATCH_B1
+            tya
+            ldy  _tmp
+            jsr  GIVAYF                 ; load it as signed... correct afterwards
+            lda  P8ZP_SCRATCH_B1
+            bpl  +
+            lda  #<_flt65536
+            ldy  #>_flt65536
+            jsr  ROMUPK
+            jsr  FADDT
++           ldx  P8ZP_SCRATCH_REG
+            rts
+_tmp        .byte 0
+_flt65536   .byte 145,0,0,0,0       ; 65536.0
+	}}
+}
+
+
+asmsub  GIVAYFAY  (uword value @ AY) clobbers(A,X,Y)  {
+	; ---- signed 16 bit word in A/Y (lo/hi) to float in fac1
+	%asm {{
+		sta  P8ZP_SCRATCH_B1
+		tya
+		ldy  P8ZP_SCRATCH_B1
+		jmp  GIVAYF		; this uses the inverse order, Y/A
+	}}
+}
+
+asmsub  GETADRAY  () clobbers(X) -> uword @ AY  {
+	; ---- fac1 to unsigned word in A/Y
+	%asm {{
+		jsr  GETADR		; this uses the inverse order, Y/A
+		sta  P8ZP_SCRATCH_B1
+		tya
+		ldy  P8ZP_SCRATCH_B1
+		rts
+	}}
+}
+
+asmsub  FREADUY (ubyte value @Y) {
+    ; -- 8 bit unsigned Y -> float in fac1
+    %asm {{
+        lda  #0
+        jmp  GIVAYF
+    }}
+}
+
+sub  print_f  (float value) {
+	; ---- prints the floating point value (without a newline).
+	%asm {{
+		stx  P8ZP_SCRATCH_REG
+		lda  #<value
+		ldy  #>value
+		jsr  MOVFM		; load float into fac1
+		jsr  FOUT		; fac1 to string in A/Y
+		sta  P8ZP_SCRATCH_W1
+		sty  P8ZP_SCRATCH_W1+1
+		ldy  #0
+-		lda  (P8ZP_SCRATCH_W1),y
+		beq  +
+		jsr  c64.CHROUT
+		iny
+		bne  -
++		ldx  P8ZP_SCRATCH_REG
+		rts
+	}}
+}
+
+%asminclude "library:c128/floats.asm"
+%asminclude "library:c64/floats_funcs.asm"
+
+}