7.1 beta

this is closer to the convention of most functional return types

.gitignore

@@ -26,8 +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/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/libraries/antlr_4_9_complete.xml

@@ -1,9 +0,0 @@
-<component name="libraryTable">
-  <library name="antlr-4.9-complete">
-    <CLASSES>
-      <root url="jar://$PROJECT_DIR$/parser/antlr/lib/antlr-4.9-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_9.xml

@@ -1,9 +0,0 @@
-<component name="libraryTable">
-  <library name="antlr-runtime-4.9">
-    <CLASSES>
-      <root url="jar://$PROJECT_DIR$/parser/antlr/lib/antlr-runtime-4.9.jar!/" />
-    </CLASSES>
-    <JAVADOC />
-    <SOURCES />
-  </library>
-</component>

.idea/libraries/dbus_java_3_2_4.xml

@@ -1,9 +0,0 @@
-<component name="libraryTable">
-  <library name="dbus-java-3.2.4">
-    <CLASSES>
-      <root url="jar://$PROJECT_DIR$/dbusCompilerService/lib/dbus-java-3.2.4.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:3.3.0" />
+    <CLASSES>
+      <root url="jar://$MAVEN_REPOSITORY$/com/github/hypfvieh/dbus-java/3.3.0/dbus-java-3.3.0.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/com/github/jnr/jnr-unixsocket/0.38.5/jnr-unixsocket-0.38.5.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/com/github/jnr/jnr-ffi/2.2.1/jnr-ffi-2.2.1.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/9.0/asm-9.0.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/ow2/asm/asm-commons/9.0/asm-commons-9.0.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/ow2/asm/asm-analysis/9.0/asm-analysis-9.0.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/ow2/asm/asm-tree/9.0/asm-tree-9.0.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/ow2/asm/asm-util/9.0/asm-util-9.0.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/0.32.3/jnr-enxio-0.32.3.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/com/github/jnr/jnr-posix/3.1.4/jnr-posix-3.1.4.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/hamcrest.xml

@@ -0,0 +1,10 @@
+<component name="libraryTable">
+  <library name="hamcrest" type="repository">
+    <properties maven-id="org.hamcrest:hamcrest:2.2" />
+    <CLASSES>
+      <root url="jar://$MAVEN_REPOSITORY$/org/hamcrest/hamcrest/2.2/hamcrest-2.2.jar!/" />
+    </CLASSES>
+    <JAVADOC />
+    <SOURCES />
+  </library>
+</component>

.idea/libraries/javax_json_api_1_1_4.xml

@@ -1,10 +0,0 @@
-<component name="libraryTable">
-  <library name="javax.json-api-1.1.4">
-    <CLASSES>
-      <root url="jar://$PROJECT_DIR$/httpCompilerService/lib/javax.json-api-1.1.4.jar!/" />
-      <root url="jar://$PROJECT_DIR$/httpCompilerService/lib/javax.json-1.1.4.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/junit_jupiter.xml

@@ -0,0 +1,17 @@
+<component name="libraryTable">
+  <library name="junit.jupiter" type="repository">
+    <properties maven-id="org.junit.jupiter:junit-jupiter:5.7.2" />
+    <CLASSES>
+      <root url="jar://$MAVEN_REPOSITORY$/org/junit/jupiter/junit-jupiter/5.7.2/junit-jupiter-5.7.2.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/junit/jupiter/junit-jupiter-api/5.7.2/junit-jupiter-api-5.7.2.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/apiguardian/apiguardian-api/1.1.0/apiguardian-api-1.1.0.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/opentest4j/opentest4j/1.2.0/opentest4j-1.2.0.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/junit/platform/junit-platform-commons/1.7.2/junit-platform-commons-1.7.2.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/junit/jupiter/junit-jupiter-params/5.7.2/junit-jupiter-params-5.7.2.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/junit/jupiter/junit-jupiter-engine/5.7.2/junit-jupiter-engine-5.7.2.jar!/" />
+      <root url="jar://$MAVEN_REPOSITORY$/org/junit/platform/junit-platform-engine/1.7.2/junit-platform-engine-1.7.2.jar!/" />
+    </CLASSES>
+    <JAVADOC />
+    <SOURCES />
+  </library>
+</component>

.idea/libraries/kotlinx_cli_jvm.xml

@@ -1,9 +0,0 @@
-<component name="libraryTable">
-  <library name="kotlinx-cli-jvm">
-    <CLASSES>
-      <root url="jar://$PROJECT_DIR$/compiler/lib/kotlinx-cli-jvm-0.3.1.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_api_1_7_30.xml

@@ -1,10 +0,0 @@
-<component name="libraryTable">
-  <library name="slf4j-api-1.7.30">
-    <CLASSES>
-      <root url="jar://$PROJECT_DIR$/httpCompilerService/lib/slf4j-api-1.7.30.jar!/" />
-      <root url="jar://$PROJECT_DIR$/httpCompilerService/lib/slf4j-simple-1.7.30.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/takes_http.xml

@@ -1,12 +0,0 @@
-<component name="libraryTable">
-  <library name="takes-http">
-    <CLASSES>
-      <root url="jar://$PROJECT_DIR$/httpCompilerService/lib/cactoos-0.42.jar!/" />
-      <root url="jar://$PROJECT_DIR$/httpCompilerService/lib/commons-lang3-3.7.jar!/" />
-      <root url="jar://$PROJECT_DIR$/httpCompilerService/lib/commons-text-1.4.jar!/" />
-      <root url="jar://$PROJECT_DIR$/httpCompilerService/lib/takes-1.19.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 +16,7 @@
       </list>
     </option>
   </component>
-  <component name="ProjectRootManager" version="2" languageLevel="JDK_11" default="false" project-jdk-name="Kotlin SDK" project-jdk-type="KotlinSDK">
+  <component name="ProjectRootManager" version="2" languageLevel="JDK_11" project-jdk-name="Kotlin SDK" project-jdk-type="KotlinSDK">
     <output url="file://$PROJECT_DIR$/out" />
   </component>
-</project>
+</project>

.travis.yml

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

CompilerDevelopment.md

@@ -0,0 +1,32 @@
+#### 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:
+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

@@ -1,5 +1,3 @@
-[![saythanks](https://img.shields.io/badge/say-thanks-ff69b4.svg)](https://saythanks.io/to/irmen)
-[![Build Status](https://travis-ci.org/irmen/prog8.svg?branch=master)](https://travis-ci.org/irmen/prog8)
 [![Documentation](https://readthedocs.org/projects/prog8/badge/?version=latest)](https://prog8.readthedocs.io/)
 
 Prog8 - Structured Programming Language for 8-bit 6502/65c02 microprocessors
@@ -7,9 +5,6 @@ Prog8 - Structured Programming Language for 8-bit 6502/65c02 microprocessors
 
 *Written by Irmen de Jong (irmen@razorvine.net)*
 
-*Software license: GNU GPL 3.0, see file LICENSE*
-
-
 This is a structured programming language for the 8-bit 6502/6510/65c02 microprocessor from the late 1970's and 1980's
 as used in many home computers from that era. It is a medium to low level programming language,
 which aims to provide many conveniences over raw assembly code (even when using a macro assembler).
@@ -19,29 +14,35 @@ 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
+- 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
-- sane variable initialization, programs can be restarted again just fine after exiting to basic
+- programs can be run multiple times without reloading because of automatic variable (re)initializations.
 - conditional branches
-- floating point operations  (requires the C64 Basic ROM routines for this)
 - 'when' statement to provide a concise jump table alternative to if/elseif chains
-- structs to group together sets of variables and manipulate them at once
 - many built-in functions such as ``sin``, ``cos``, ``rnd``, ``abs``, ``min``, ``max``, ``sqrt``, ``msb``, ``rol``, ``ror``, ``swap``, ``sort`` and ``reverse``
 - various powerful built-in libraries to do I/O, number conversions, graphics and more  
 - convenience abstractions for low level aspects such as ZeroPage handling, program startup, explicit memory addresses
-- fast execution speed due to compilation to native assembly code
-- variables are allocated statically
 - inline assembly allows you to have full control when every cycle or byte matters
-- supports the sixteen 'virtual' 16-bit registers R0 .. R15 from the Commander X16, and provides them also on the C64.
+- 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:*

build.gradle

@@ -0,0 +1,3 @@
+plugins {
+    id "org.jetbrains.kotlin.jvm" version "1.5.30" apply false
+}

compiler/build.gradle

@@ -1,14 +1,14 @@
 plugins {
     id 'java'
     id 'application'
-    id "org.jetbrains.kotlin.jvm" version "1.4.30"
-    id 'org.jetbrains.dokka' version "0.9.18"
-    id 'com.github.johnrengelman.shadow' version '6.1.0'
+    id "org.jetbrains.kotlin.jvm"
+    id 'com.github.johnrengelman.shadow' version '7.1.0'
 }
 
 targetCompatibility = 11
 sourceCompatibility = 11
 
+
 repositories {
     mavenLocal()
     mavenCentral()
@@ -21,16 +21,29 @@ dependencies {
     implementation project(':compilerAst')
     implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8"
     // implementation "org.jetbrains.kotlin:kotlin-reflect"
-    implementation 'org.jetbrains.kotlinx:kotlinx-cli:0.3.1'
-    // implementation 'net.razorvine:ksim65:1.8'
-    // implementation "com.github.hypfvieh:dbus-java:3.2.4"
+    implementation 'org.jetbrains.kotlinx:kotlinx-cli:0.3.3'
+    implementation "com.michael-bull.kotlin-result:kotlin-result-jvm:1.1.12"
 
     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'
+    testImplementation 'org.junit.jupiter:junit-jupiter-api:5.7.2'
+    testImplementation 'org.hamcrest:hamcrest:2.2'
+    testRuntimeOnly 'org.junit.jupiter:junit-jupiter-engine:5.7.2'
 }
 
+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 }
+    }
+}
+
+
 compileKotlin {
     kotlinOptions {
         jvmTarget = "11"
@@ -58,7 +71,8 @@ sourceSets {
     }
     test {
         java {
-            srcDirs = ["${project.projectDir}/test"]
+            srcDir "${project.projectDir}/test"
+            srcDir "${project(':compilerAst').projectDir}/test/helpers"
         }
     }
 }
@@ -67,7 +81,6 @@ startScripts.enabled = true
 
 application {
     mainClass = 'prog8.CompilerMainKt'
-    mainClassName = 'prog8.CompilerMainKt'  // deprecated
     applicationName = 'p8compile'
 }
 
@@ -95,13 +108,3 @@ test {
         events "skipped", "failed"
     }
 }
-
-
-dokka {
-    outputFormat = 'html'
-    outputDirectory = "$buildDir/kdoc"
-}
-
-task wrapper(type: Wrapper) {
-    gradleVersion = '6.7'
-}

compiler/compiler.iml

@@ -13,12 +13,14 @@
       <sourceFolder url="file://$MODULE_DIR$/test" isTestSource="true" />
       <excludeFolder url="file://$MODULE_DIR$/build" />
     </content>
-    <orderEntry type="jdk" jdkName="11" jdkType="JavaSDK" />
+    <orderEntry type="jdk" jdkName="openjdk-11" jdkType="JavaSDK" />
     <orderEntry type="sourceFolder" forTests="false" />
     <orderEntry type="library" name="KotlinJavaRuntime" level="project" />
-    <orderEntry type="library" name="unittest-libs" level="project" />
-    <orderEntry type="library" name="kotlinx-cli-jvm" level="project" />
     <orderEntry type="module" module-name="compilerAst" />
     <orderEntry type="library" name="Python 3.9 interpreter library" level="application" />
+    <orderEntry type="library" name="hamcrest" level="project" />
+    <orderEntry type="library" name="jetbrains.kotlinx.cli.jvm" level="project" />
+    <orderEntry type="library" name="junit.jupiter" level="project" />
+    <orderEntry type="library" name="michael.bull.kotlin.result.jvm" level="project" />
   </component>
 </module>

compiler/res/prog8lib/c64/floats.p8

@@ -4,7 +4,6 @@
 ;
 ; indent format: TABS, size=8
 
-%target c64
 %option enable_floats
 
 floats {
@@ -83,7 +82,7 @@ romsub $bc58 = ABS()                                        ; fac1 = ABS(fac1)
 romsub $bf71 = SQR() clobbers(A,X,Y)                        ; fac1 = SQRT(fac1)
 romsub $bf74 = SQRA() clobbers(A,X,Y)                       ; fac1 = SQRT(fac2)
 romsub $bfed = EXP() clobbers(A,X,Y)                        ; fac1 = EXP(fac1)  (e ** fac1)
-romsub $bfb4 = NEGOP() clobbers(A)                          ; switch the sign of fac1
+romsub $bfb4 = NEGOP() clobbers(A)                          ; switch the sign of fac1 (fac1 = -fac1)
 romsub $e097 = RND() clobbers(A,X,Y)                        ; fac1 = RND(fac1) float random number generator
 romsub $e264 = COS() clobbers(A,X,Y)                        ; fac1 = COS(fac1)
 romsub $e26b = SIN() clobbers(A,X,Y)                        ; fac1 = SIN(fac1)
@@ -195,7 +194,7 @@ sub  print_f  (float value) {
 	}}
 }
 
-%asminclude "library:c64/floats.asm", ""
-%asminclude "library:c64/floats_funcs.asm", ""
+%asminclude "library:c64/floats.asm"
+%asminclude "library:c64/floats_funcs.asm"
 
 }

compiler/res/prog8lib/c64/graphics.p8

@@ -1,4 +1,3 @@
-%target c64
 %import textio
 
 ; bitmap pixel graphics module for the C64

compiler/res/prog8lib/c64/syslib.p8

@@ -5,8 +5,6 @@
 ;
 ; indent format: TABS, size=8
 
-%target c64
-
 c64 {
         &ubyte  TIME_HI         = $a0       ; software jiffy clock, hi byte
         &ubyte  TIME_MID        = $a1       ;  .. mid byte
@@ -214,7 +212,7 @@ romsub $FFD2 = CHROUT(ubyte char @ A)                           ; (via 806 ($326
 romsub $FFD5 = LOAD(ubyte verify @ A, uword address @ XY) -> ubyte @Pc, ubyte @ A, uword @ XY     ; (via 816 ($330)) load from device
 romsub $FFD8 = SAVE(ubyte zp_startaddr @ A, uword endaddr @ XY) -> ubyte @ Pc, ubyte @ A          ; (via 818 ($332)) save to a device
 romsub $FFDB = SETTIM(ubyte low @ A, ubyte middle @ X, ubyte high @ Y)      ; set the software clock
-romsub $FFDE = RDTIM() -> ubyte @ A, ubyte @ X, ubyte @ Y       ; read the software clock
+romsub $FFDE = RDTIM() -> ubyte @ A, ubyte @ X, ubyte @ Y       ; read the software clock (A=lo,X=mid,Y=high)
 romsub $FFE1 = STOP() clobbers(X) -> ubyte @ Pz, ubyte @ A      ; (via 808 ($328)) check the STOP key (and some others in A)
 romsub $FFE4 = GETIN() clobbers(X,Y) -> ubyte @Pc, ubyte @ A    ; (via 810 ($32A)) get a character
 romsub $FFE7 = CLALL() clobbers(A,X)                            ; (via 812 ($32C)) close all files
@@ -246,7 +244,7 @@ asmsub STOP2() -> ubyte @A  {
 }
 
 asmsub RDTIM16() -> uword @AY {
-    ; --  like RDTIM() but only returning the lower 16 bits for convenience
+    ; --  like RDTIM() but only returning the lower 16 bits in AY for convenience
     %asm {{
         stx  P8ZP_SCRATCH_REG
         jsr  c64.RDTIM
@@ -478,7 +476,7 @@ sys {
 
 
     asmsub  reset_system()  {
-        ; Soft-reset the system back to Basic prompt.
+        ; Soft-reset the system back to initial power-on Basic prompt.
         %asm {{
             sei
             lda  #14
@@ -489,6 +487,7 @@ sys {
 
     sub wait(uword jiffies) {
         ; --- wait approximately the given number of jiffies (1/60th seconds)
+        ;     note: the system irq handler has to be active for this to work as it depends on the system jiffy clock
         repeat jiffies {
             ubyte jiff = lsb(c64.RDTIM16())
             while jiff==lsb(c64.RDTIM16()) {
@@ -497,6 +496,27 @@ sys {
         }
     }
 
+    asmsub waitvsync() clobbers(A) {
+        ; --- busy wait till the next vsync has occurred (approximately), without depending on custom irq handling.
+        ;     note: a more accurate way to wait for vsync is to set up a vsync irq handler instead.
+        %asm {{
+-           bit  c64.SCROLY
+            bpl  -
+-           bit  c64.SCROLY
+            bmi  -
+            rts
+        }}
+    }
+
+    inline asmsub waitrastborder() {
+        ; --- busy wait till the raster position has reached the bottom screen border (approximately)
+        ;     note: a more accurate way to do this is by using a raster irq handler instead.
+        %asm {{
+-           bit  c64.SCROLY
+            bpl  -
+        }}
+    }
+
     asmsub memcopy(uword source @R0, uword target @R1, uword count @AY) clobbers(A,X,Y) {
         %asm {{
             ldx  cx16.r0
@@ -679,4 +699,37 @@ cx16 {
     &uword r14 = $cf1c
     &uword r15 = $cf1e
 
+    &ubyte r0L  = $cf00
+    &ubyte r1L  = $cf02
+    &ubyte r2L  = $cf04
+    &ubyte r3L  = $cf06
+    &ubyte r4L  = $cf08
+    &ubyte r5L  = $cf0a
+    &ubyte r6L  = $cf0c
+    &ubyte r7L  = $cf0e
+    &ubyte r8L  = $cf10
+    &ubyte r9L  = $cf12
+    &ubyte r10L = $cf14
+    &ubyte r11L = $cf16
+    &ubyte r12L = $cf18
+    &ubyte r13L = $cf1a
+    &ubyte r14L = $cf1c
+    &ubyte r15L = $cf1e
+
+    &ubyte r0H  = $cf01
+    &ubyte r1H  = $cf03
+    &ubyte r2H  = $cf05
+    &ubyte r3H  = $cf07
+    &ubyte r4H  = $cf09
+    &ubyte r5H  = $cf0b
+    &ubyte r6H  = $cf0d
+    &ubyte r7H  = $cf0f
+    &ubyte r8H  = $cf11
+    &ubyte r9H  = $cf13
+    &ubyte r10H = $cf15
+    &ubyte r11H = $cf17
+    &ubyte r12H = $cf19
+    &ubyte r13H = $cf1b
+    &ubyte r14H = $cf1d
+    &ubyte r15H = $cf1f
 }

compiler/res/prog8lib/c64/textio.p8

@@ -4,7 +4,6 @@
 ;
 ; indent format: TABS, size=8
 
-%target c64
 %import syslib
 %import conv
 

compiler/res/prog8lib/cx16/floats.p8

@@ -4,11 +4,12 @@
 ;
 ; indent format: TABS, size=8
 
-%target cx16
 %option enable_floats
 
 floats {
-	; ---- this block contains C-64 floating point related functions ----
+	; ---- this block contains C-64 compatible floating point related functions ----
+	;      the addresses are from cx16 V39 emulator and roms! they won't work on older versions.
+
 
         const float  PI     = 3.141592653589793
         const float  TWOPI  = 6.283185307179586
@@ -43,36 +44,34 @@ romsub $fe1e = NORMAL() clobbers(A,X,Y)                     ; normalize fac1 (?)
 romsub $fe24 = LOG() clobbers(A,X,Y)                        ; fac1 = LN(fac1)  (natural log)
 romsub $fe27 = FMULT(uword mflpt @ AY) clobbers(A,X,Y)      ; fac1 *= mflpt value from A/Y
 romsub $fe2a = FMULTT() clobbers(A,X,Y)                     ; fac1 *= fac2
-romsub $fe33 = CONUPK(uword mflpt @ AY) clobbers(A,Y)       ; load mflpt value from memory  in A/Y into fac2
-romsub $fe36 = MUL10() clobbers(A,X,Y)                      ; fac1 *= 10
-romsub $fe3c = DIV10() clobbers(A,X,Y)                      ; fac1 /= 10 , CAUTION: result is always positive!
-romsub $fe3f = FDIV(uword mflpt @ AY) clobbers(A,X,Y)       ; fac1 = mflpt in A/Y / fac1  (remainder in fac2)
-romsub $fe42 = FDIVT() clobbers(A,X,Y)                      ; fac1 = fac2/fac1  (remainder in fac2)  mind the order of the operands
+romsub $fe30 = CONUPK(uword mflpt @ AY) clobbers(A,X,Y)     ; load mflpt value from memory  in A/Y into fac2
+romsub $fe33 = MUL10() clobbers(A,X,Y)                      ; fac1 *= 10
+romsub $fe36 = DIV10() clobbers(A,X,Y)                      ; fac1 /= 10 , CAUTION: result is always positive!
+romsub $fe39 = FDIV(uword mflpt @ AY) clobbers(A,X,Y)       ; fac1 = mflpt in A/Y / fac1  (remainder in fac2)
+romsub $fe3c = FDIVT() clobbers(A,X,Y)                      ; fac1 = fac2/fac1  (remainder in fac2)  mind the order of the operands
 
-romsub $fe48 = MOVFM(uword mflpt @ AY) clobbers(A,Y)        ; load mflpt value from memory  in A/Y into fac1
-romsub $fe4b = MOVMF(uword mflpt @ XY) clobbers(A,Y)        ; store fac1 to memory  X/Y as 5-byte mflpt
-romsub $fe4e = MOVFA() clobbers(A,X)                        ; copy fac2 to fac1
-romsub $fe51 = MOVAF() clobbers(A,X)                        ; copy fac1 to fac2  (rounded)
-romsub $fe54 = MOVEF() clobbers(A,X)                        ; copy fac1 to fac2
-romsub $fe5a = SIGN() -> ubyte @ A                          ; SIGN(fac1) to A, $ff, $0, $1 for negative, zero, positive
-romsub $fe5d = SGN() clobbers(A,X,Y)                        ; fac1 = SGN(fac1), result of SIGN (-1, 0 or 1)
-romsub $fe60 = FREADSA(byte value @ A) clobbers(A,X,Y)      ; 8 bit signed A -> float in fac1
-romsub $fe6c = ABS()                                        ; fac1 = ABS(fac1)
-romsub $fe6f = 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 $fe78 = INT() clobbers(A,X,Y)                        ; INT() truncates, use FADDH first to round instead of trunc
-romsub $fe7e = FINLOG(byte value @A) clobbers (A, X, Y)           ; fac1 += signed byte in A
-romsub $fe81 = FOUT() clobbers(X) -> uword @ AY             ; fac1 -> string, address returned in AY
-romsub $fe8a = SQR() clobbers(A,X,Y)                        ; fac1 = SQRT(fac1)
-romsub $fe8d = FPWRT() clobbers(A,X,Y)                      ; fac1 = fac2 ** fac1
-; note: there is no FPWR() on the Cx16
-romsub $fe93 = NEGOP() clobbers(A)                          ; switch the sign of fac1
-romsub $fe96 = EXP() clobbers(A,X,Y)                        ; fac1 = EXP(fac1)  (e ** fac1)
-romsub $fe9f = RND2(byte value @A) clobbers(A,X,Y)                ; fac1 = RND(A) float random number generator
-romsub $fea2 = RND() clobbers(A,X,Y)                        ; fac1 = RND(fac1) float random number generator
-romsub $fea5 = COS() clobbers(A,X,Y)                        ; fac1 = COS(fac1)
-romsub $fea8 = SIN() clobbers(A,X,Y)                        ; fac1 = SIN(fac1)
-romsub $feab = TAN() clobbers(A,X,Y)                        ; fac1 = TAN(fac1)
-romsub $feae = ATN() clobbers(A,X,Y)                        ; fac1 = ATN(fac1)
+romsub $fe42 = MOVFM(uword mflpt @ AY) clobbers(A,X,Y)      ; load mflpt value from memory  in A/Y into fac1
+romsub $fe45 = MOVMF(uword mflpt @ XY) clobbers(A,X,Y)      ; store fac1 to memory  X/Y as 5-byte mflpt
+romsub $fe48 = MOVFA() clobbers(A,X)                        ; copy fac2 to fac1
+romsub $fe4b = MOVAF() clobbers(A,X)                        ; copy fac1 to fac2  (rounded)
+romsub $fe4e = MOVEF() clobbers(A,X)                        ; copy fac1 to fac2
+romsub $fe54 = SIGN() clobbers(X,Y) -> ubyte @ A            ; SIGN(fac1) to A, $ff, $0, $1 for negative, zero, positive
+romsub $fe57 = SGN() clobbers(A,X,Y)                        ; fac1 = SGN(fac1), result of SIGN (-1, 0 or 1)
+romsub $fe5a = FREADSA(byte value @ A) clobbers(A,X,Y)      ; 8 bit signed A -> float in fac1
+romsub $fe66 = ABS() clobbers(A,X,Y)                        ; fac1 = ABS(fac1)
+romsub $fe69 = 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 $fe72 = INT() clobbers(A,X,Y)                        ; INT() truncates, use FADDH first to round instead of trunc
+romsub $fe78 = FINLOG(byte value @A) clobbers (A, X, Y)           ; fac1 += signed byte in A
+romsub $fe7b = FOUT() clobbers(X) -> uword @ AY             ; fac1 -> string, address returned in AY
+romsub $fe81 = SQR() clobbers(A,X,Y)                        ; fac1 = SQRT(fac1)
+romsub $fe84 = FPWRT() clobbers(A,X,Y)                      ; fac1 = fac2 ** fac1
+romsub $fe8a = NEGOP() clobbers(A)                          ; switch the sign of fac1 (fac1 = -fac1)
+romsub $fe8d = EXP() clobbers(A,X,Y)                        ; fac1 = EXP(fac1)  (e ** fac1)
+romsub $fe96 = RND() clobbers(A,X,Y)                        ; fac1 = RND(fac1) float random number generator
+romsub $fe99 = COS() clobbers(A,X,Y)                        ; fac1 = COS(fac1)
+romsub $fe9c = SIN() clobbers(A,X,Y)                        ; fac1 = SIN(fac1)
+romsub $fe9f = TAN() clobbers(A,X,Y)                        ; fac1 = TAN(fac1)
+romsub $fea2 = ATN() clobbers(A,X,Y)                        ; fac1 = ATN(fac1)
 
 
 asmsub  GIVUAYFAY  (uword value @ AY) clobbers(A,X,Y)  {
@@ -158,7 +157,7 @@ sub  print_f  (float value) {
 	}}
 }
 
-%asminclude "library:c64/floats.asm", ""
-%asminclude "library:c64/floats_funcs.asm", ""
+%asminclude "library:c64/floats.asm"
+%asminclude "library:c64/floats_funcs.asm"
 
 }

compiler/res/prog8lib/cx16/gfx2.p8

@@ -1,5 +1,3 @@
-%target cx16
-
 ; Bitmap pixel graphics routines for the CommanderX16
 ; Custom routines to use the full-screen 640x480 and 320x240 screen modes.
 ; (These modes are not supported by the documented GRAPH_xxxx kernal routines)
@@ -22,6 +20,7 @@
 ;   mode 6 = bitmap 640 x 480 x 4c
 ;   higher color dephts in highres are not supported due to lack of VRAM
 
+
 ; TODO can we make a FB vector table and emulation routines for the Cx16s' GRAPH_init() call? to replace the builtin 320x200 fb driver?
 
 gfx2 {
@@ -274,9 +273,9 @@ _done
                         ora  colorbits,y
                         sta  cx16.VERA_DATA0
                         cpy  #%00000011         ; next vera byte?
-                        bne  +
+                        bne  ++
                         inc  cx16.VERA_ADDR_L
-                        bne  +
+                        bne  ++
                         inc  cx16.VERA_ADDR_M
 +                       bne  +
                         inc  cx16.VERA_ADDR_H
@@ -292,92 +291,56 @@ _done
     }
 
     sub vertical_line(uword x, uword y, uword height, ubyte color) {
-        position(x,y)
         when active_mode {
             1, 5 -> {
-                ; monochrome, either resolution
-                ; note for the 1 bpp modes we can't use vera's auto increment mode because we have to 'or' the pixel data in place.
-                ; TODO use TWO vera adress pointers simultaneously one for reading, one for writing, so auto-increment IS possible
-                cx16.VERA_ADDR_H &= %00000111   ; no auto advance
-                cx16.r15 = gfx2.plot.bits[x as ubyte & 7]           ; bitmask
-                if active_mode>=5
-                    cx16.r14 = 640/8
-                else
-                    cx16.r14 = 320/8
+                ; monochrome, lo-res
+                cx16.r15L = gfx2.plot.bits[x as ubyte & 7]           ; bitmask
                 if color {
                     if monochrome_dont_stipple_flag {
+                        ; draw continuous line.
+                        position2(x,y,true)
+                        if active_mode==1
+                            set_both_strides(11)    ; 40 increment = 1 line in 320 px monochrome
+                        else
+                            set_both_strides(12)    ; 80 increment = 1 line in 640 px monochrome
                         repeat height {
                             %asm {{
                                 lda  cx16.VERA_DATA0
-                                ora  cx16.r15
-                                sta  cx16.VERA_DATA0
-                                lda  cx16.VERA_ADDR_L
-                                clc
-                                adc  cx16.r14                 ; advance vera ptr to go to the next line
-                                sta  cx16.VERA_ADDR_L
-                                lda  cx16.VERA_ADDR_M
-                                adc  #0
-                                sta  cx16.VERA_ADDR_M
-                                ; lda  cx16.VERA_ADDR_H     ; the bitmap size is small enough to not have to deal with the _H part.
-                                ; adc  #0
-                                ; sta  cx16.VERA_ADDR_H
+                                ora  cx16.r15L
+                                sta  cx16.VERA_DATA1
                             }}
                         }
                     } else {
-                        ; stippling.
-                        height = (height+1)/2       ; TODO is the line sometimes 1 pixel too long now because of rounding?
-                        %asm {{
-                            lda x
-                            eor y
-                            and #1
-                            bne +
-                            lda  cx16.VERA_ADDR_L
-                            clc
-                            adc  cx16.r14                ; advance vera ptr to go to the next line for correct stipple pattern
-                            sta  cx16.VERA_ADDR_L
-                            lda  cx16.VERA_ADDR_M
-                            adc  #0
-                            sta  cx16.VERA_ADDR_M
-        +
-                            asl  cx16.r14
-                            ldy  height
-                            beq  +
-        -                   lda  cx16.VERA_DATA0
-                            ora  cx16.r15
-                            sta  cx16.VERA_DATA0
-                            lda  cx16.VERA_ADDR_L
-                            clc
-                            adc  cx16.r14               ; advance vera data ptr to go to the next-next line
-                            sta  cx16.VERA_ADDR_L
-                            lda  cx16.VERA_ADDR_M
-                            adc  #0
-                            sta  cx16.VERA_ADDR_M
-                            ; lda  cx16.VERA_ADDR_H      ; the bitmap size is small enough to not have to deal with the _H part.
-                            ; adc  #0
-                            ; sta  cx16.VERA_ADDR_H
-                            dey
-                            bne  -
-        +
-                        }}
+                        ; draw stippled line.
+                        if x&1 {
+                            y++
+                            height--
+                        }
+                        position2(x,y,true)
+                        if active_mode==1
+                            set_both_strides(12)    ; 80 increment = 2 line in 320 px monochrome
+                        else
+                            set_both_strides(13)    ; 160 increment = 2 line in 640 px monochrome
+                        repeat height/2 {
+                            %asm {{
+                                lda  cx16.VERA_DATA0
+                                ora  cx16.r15L
+                                sta  cx16.VERA_DATA1
+                            }}
+                        }
                     }
                 } else {
-                    cx16.r15 = ~cx16.r15
+                    position2(x,y,true)
+                    cx16.r15 = ~cx16.r15    ; erase pixels
+                    if active_mode==1
+                        set_both_strides(11)    ; 40 increment = 1 line in 320 px monochrome
+                    else
+                        set_both_strides(12)    ; 80 increment = 1 line in 640 px monochrome
                     repeat height {
                         %asm {{
                             lda  cx16.VERA_DATA0
-                            and  cx16.r15
-                            sta  cx16.VERA_DATA0
-                            lda  cx16.VERA_ADDR_L
-                            clc
-                            adc  cx16.r14             ; advance vera data ptr to go to the next line
-                            sta  cx16.VERA_ADDR_L
-                            lda  cx16.VERA_ADDR_M
-                            adc  #0
-                            sta  cx16.VERA_ADDR_M
-                            ; the bitmap size is small enough to not have to deal with the _H part:
-                            ; lda  cx16.VERA_ADDR_H
-                            ; adc  #0
-                            ; sta  cx16.VERA_ADDR_H
+                            and  cx16.r15L
+                            sta  cx16.VERA_DATA1
                         }}
                     }
                 }
@@ -385,6 +348,7 @@ _done
             4 -> {
                 ; lores 256c
                 ; set vera auto-increment to 320 pixel increment (=next line)
+                position(x,y)
                 cx16.VERA_ADDR_H = cx16.VERA_ADDR_H & %00000111 | (14<<4)
                 %asm {{
                     ldy  height
@@ -398,36 +362,33 @@ _done
             }
             6 -> {
                 ; highres 4c
-                ; note for this mode we can't use vera's auto increment mode because we have to 'or' the pixel data in place.
-                ; TODO use TWO vera adress pointers simultaneously one for reading, one for writing, so auto-increment IS possible
-                cx16.VERA_ADDR_H &= %00000111   ; no auto advance
-                ; TODO also mostly usable for lores 4c?
-                void addr_mul_24_for_highres_4c(y, x)      ; 24 bits result is in r0 and r1L (highest byte)
-
-                ; TODO optimize this vertical line loop in pure assembly
+                ; use TWO vera adress pointers simultaneously one for reading, one for writing, so auto-increment is possible
+                if height==0
+                    return
+                position2(x,y,true)
+                set_both_strides(13)    ; 160 increment = 1 line in 640 px 4c mode
                 color &= 3
                 color <<= gfx2.plot.shift4c[lsb(x) & 3]
                 ubyte mask = gfx2.plot.mask4c[lsb(x) & 3]
                 repeat height {
-                    ubyte value = cx16.vpeek(lsb(cx16.r1), cx16.r0) & mask | color
-                    cx16.vpoke(lsb(cx16.r1), cx16.r0, value)
                     %asm {{
-                        ; 24 bits add 160 (640/4)
-                        clc
-                        lda  cx16.r0
-                        adc  #640/4
-                        sta  cx16.r0
-                        lda  cx16.r0+1
-                        adc  #0
-                        sta  cx16.r0+1
-                        bcc  +
-                        inc  cx16.r1
-+
+                        lda  cx16.VERA_DATA0
+                        and  mask
+                        ora  color
+                        sta  cx16.VERA_DATA1
                     }}
                 }
             }
         }
 
+        sub set_both_strides(ubyte stride) {
+            stride <<= 4
+            cx16.VERA_CTRL = 0
+            cx16.VERA_ADDR_H = cx16.VERA_ADDR_H & %00000111 | stride
+            cx16.VERA_CTRL = 1
+            cx16.VERA_ADDR_H = cx16.VERA_ADDR_H & %00000111 | stride
+        }
+
     }
 
     sub line(uword @zp x1, uword @zp y1, uword @zp x2, uword @zp y2, ubyte color) {
@@ -587,8 +548,6 @@ _done
         ubyte[8] bits = [128, 64, 32, 16, 8, 4, 2, 1]
         ubyte[4] mask4c = [%00111111, %11001111, %11110011, %11111100]
         ubyte[4] shift4c = [6,4,2,0]
-        uword addr
-        ubyte value
 
         when active_mode {
             1 -> {
@@ -600,23 +559,43 @@ _done
                     and  #1
                 }}
                 if_nz {
-                    addr = x/8 + y*(320/8)
-                    value = bits[lsb(x)&7]
-                    if color
-                        cx16.vpoke_or(0, addr, value)
-                    else {
-                        value = ~value
-                        cx16.vpoke_and(0, addr, value)
-                    }
+                    cx16.r0L = lsb(x) & 7       ; xbits
+                    x /= 8
+                    x += y*(320/8)
+                    %asm {{
+                        stz  cx16.VERA_CTRL
+                        stz  cx16.VERA_ADDR_H
+                        lda  x+1
+                        sta  cx16.VERA_ADDR_M
+                        lda  x
+                        sta  cx16.VERA_ADDR_L
+                        ldy  cx16.r0L       ; xbits
+                        lda  bits,y
+                        ldy  color
+                        beq  +
+                        tsb  cx16.VERA_DATA0
+                        bra  ++
++                       trb  cx16.VERA_DATA0
++
+                    }}
                 }
             }
+            ; TODO mode 2,3
             4 -> {
                 ; lores 256c
                 void addr_mul_24_for_lores_256c(y, x)      ; 24 bits result is in r0 and r1L (highest byte)
-                cx16.vpoke(lsb(cx16.r1), cx16.r0, color)
-                ; activate vera auto-increment mode so next_pixel() can be used after this
-                cx16.VERA_ADDR_H = cx16.VERA_ADDR_H & %00000111 | %00010000
-                color = cx16.VERA_DATA0
+                %asm {{
+                    stz  cx16.VERA_CTRL
+                    lda  cx16.r1
+                    ora  #%00010000     ; enable auto-increment so next_pixel() can be used after this
+                    sta  cx16.VERA_ADDR_H
+                    lda  cx16.r0+1
+                    sta  cx16.VERA_ADDR_M
+                    lda  cx16.r0
+                    sta  cx16.VERA_ADDR_L
+                    lda  color
+                    sta  cx16.VERA_DATA0
+                }}
             }
             5 -> {
                 ; highres monochrome
@@ -627,26 +606,48 @@ _done
                     and  #1
                 }}
                 if_nz {
-                    addr = x/8 + y*(640/8)
-                    value = bits[lsb(x)&7]
-                    if color
-                        cx16.vpoke_or(0, addr, value)
-                    else {
-                        value = ~value
-                        cx16.vpoke_and(0, addr, value)
-                    }
+                    cx16.r0L = lsb(x) & 7       ; xbits
+                    x /= 8
+                    x += y*(640/8)
+                    %asm {{
+                        stz  cx16.VERA_CTRL
+                        stz  cx16.VERA_ADDR_H
+                        lda  x+1
+                        sta  cx16.VERA_ADDR_M
+                        lda  x
+                        sta  cx16.VERA_ADDR_L
+                        ldy  cx16.r0L           ; xbits
+                        lda  bits,y
+                        ldy  color
+                        beq  +
+                        tsb  cx16.VERA_DATA0
+                        bra  ++
++                       trb  cx16.VERA_DATA0
++
+                    }}
                 }
             }
             6 -> {
                 ; highres 4c
                 ; TODO also mostly usable for lores 4c?
                 void addr_mul_24_for_highres_4c(y, x)      ; 24 bits result is in r0 and r1L (highest byte)
+                cx16.r2L = lsb(x) & 3       ; xbits
                 color &= 3
-                color <<= shift4c[lsb(x) & 3]
-                ; TODO optimize the vera memory manipulation in pure assembly
-                cx16.VERA_ADDR_H &= %00000111   ; no auto advance
-                value = cx16.vpeek(lsb(cx16.r1), cx16.r0) & mask4c[lsb(x) & 3] | color
-                cx16.vpoke(lsb(cx16.r1), cx16.r0, value)
+                color <<= shift4c[cx16.r2L]
+                %asm {{
+                    stz  cx16.VERA_CTRL
+                    lda  cx16.r1L
+                    sta  cx16.VERA_ADDR_H
+                    lda  cx16.r0H
+                    sta  cx16.VERA_ADDR_M
+                    lda  cx16.r0L
+                    sta  cx16.VERA_ADDR_L
+                    ldy  cx16.r2L           ; xbits
+                    lda  mask4c,y
+                    and  cx16.VERA_DATA0
+                    ora  color
+                    sta  cx16.VERA_DATA0
+                }}
             }
         }
     }
@@ -680,6 +681,20 @@ _done
         }
     }
 
+    sub position2(uword @zp x, uword y, ubyte also_port_1) {
+        position(x, y)
+        if also_port_1 {
+            when active_mode {
+                1, 5 -> cx16.vaddr(0, cx16.r0, 1, 1)
+                ; TODO modes 2, 3
+                4, 6 -> {
+                    ubyte bank = lsb(cx16.r1)
+                    cx16.vaddr(bank, cx16.r0, 1, 1)
+                }
+            }
+        }
+    }
+
     inline asmsub next_pixel(ubyte color @A) {
         ; -- sets the next pixel byte to the graphics chip.
         ;    for 8 bpp screens this will plot 1 pixel.
@@ -759,13 +774,13 @@ _done
     sub text(uword @zp x, uword y, ubyte color, uword sctextptr) {
         ; -- Write some text at the given pixel position. The text string must be in screencode encoding (not petscii!).
         ;    You must also have called text_charset() first to select and prepare the character set to use.
-        ;    NOTE: in monochrome (1bpp) screen modes, x position is currently constrained to mulitples of 8 !  TODO allow per-pixel horizontal positioning
+        ;    NOTE: in monochrome (1bpp) screen modes, x position is currently constrained to multiples of 8 !  TODO allow per-pixel horizontal positioning
         uword chardataptr
         when active_mode {
             1, 5 -> {
                 ; monochrome mode, either resolution
                 cx16.r2 = 40
-                if active_mode>=5
+                if active_mode==5
                     cx16.r2 = 80
                 while @(sctextptr) {
                     chardataptr = charset_addr + (@(sctextptr) as uword)*8

compiler/res/prog8lib/cx16/graphics.p8

@@ -1,4 +1,3 @@
-%target cx16
 %import syslib
 %import textio
 

compiler/res/prog8lib/cx16/palette.p8

@@ -1,5 +1,3 @@
-%target cx16
-
 ; Manipulate the Commander X16's display color palette.
 ; Should you want to restore the default palette, you have to reinitialize the Vera yourself.
 
@@ -9,7 +7,7 @@ palette {
     ubyte c
 
     sub set_color(ubyte index, uword color) {
-        vera_palette_ptr = $fa00+index*2
+        vera_palette_ptr = $fa00+(index as uword * 2)
         cx16.vpoke(1, vera_palette_ptr, lsb(color))
         vera_palette_ptr++
         cx16.vpoke(1, vera_palette_ptr, msb(color))
@@ -70,6 +68,14 @@ palette {
         }
     }
 
+    sub set_all_black() {
+        set_monochrome($000, $000)
+    }
+
+    sub set_all_white() {
+        set_monochrome($fff, $fff)
+    }
+
     sub set_grayscale() {
         vera_palette_ptr = $fa00
         repeat 16 {

compiler/res/prog8lib/cx16/syslib.p8

@@ -5,9 +5,6 @@
 ;
 ; indent format: TABS, size=8
 
-%target cx16
-
-
 c64 {
 
 ; ---- kernal routines, these are the same as on the Commodore-64 (hence the same block name) ----
@@ -24,7 +21,7 @@ romsub $FF8D = VECTOR(uword userptr @ XY, ubyte dir @ Pc) clobbers(A,Y)     ; re
 romsub $FF90 = SETMSG(ubyte value @ A)                          ; set Kernal message control flag
 romsub $FF93 = SECOND(ubyte address @ A) clobbers(A)            ; (alias: LSTNSA) send secondary address after LISTEN
 romsub $FF96 = TKSA(ubyte address @ A) clobbers(A)              ; (alias: TALKSA) send secondary address after TALK
-romsub $FF99 = MEMTOP(uword address @ XY, ubyte dir @ Pc) -> uword @ XY     ; read/set top of memory  pointer.   NOTE: as a Cx16 extension, also returns the number of RAM memory banks in register A !  See MEMTOP2
+romsub $FF99 = MEMTOP(uword address @ XY, ubyte dir @ Pc) -> uword @ XY     ; read/set top of memory  pointer.   NOTE: as a Cx16 extension, also returns the number of RAM memory banks in register A !  See cx16.numbanks()
 romsub $FF9C = MEMBOT(uword address @ XY, ubyte dir @ Pc) -> uword @ XY     ; read/set bottom of memory  pointer
 romsub $FF9F = SCNKEY() clobbers(A,X,Y)                         ; scan the keyboard
 romsub $FFA2 = SETTMO(ubyte timeout @ A)                        ; set time-out flag for IEEE bus
@@ -47,7 +44,7 @@ romsub $FFD2 = CHROUT(ubyte char @ A)                           ; (via 806 ($326
 romsub $FFD5 = LOAD(ubyte verify @ A, uword address @ XY) -> ubyte @Pc, ubyte @ A, uword @ XY     ; (via 816 ($330)) load from device
 romsub $FFD8 = SAVE(ubyte zp_startaddr @ A, uword endaddr @ XY) -> ubyte @ Pc, ubyte @ A          ; (via 818 ($332)) save to a device
 romsub $FFDB = SETTIM(ubyte low @ A, ubyte middle @ X, ubyte high @ Y)      ; set the software clock
-romsub $FFDE = RDTIM() -> ubyte @ A, ubyte @ X, ubyte @ Y       ; read the software clock
+romsub $FFDE = RDTIM() -> ubyte @ A, ubyte @ X, ubyte @ Y       ; read the software clock (A=lo,X=mid,Y=high)
 romsub $FFE1 = STOP() clobbers(X) -> ubyte @ Pz, ubyte @ A      ; (via 808 ($328)) check the STOP key (and some others in A)
 romsub $FFE4 = GETIN() clobbers(X,Y) -> ubyte @Pc, ubyte @ A    ; (via 810 ($32A)) get a character
 romsub $FFE7 = CLALL() clobbers(A,X)                            ; (via 812 ($32C)) close all files
@@ -74,7 +71,7 @@ asmsub STOP2() -> ubyte @A  {
 }
 
 asmsub RDTIM16() -> uword @AY {
-    ; --  like RDTIM() but only returning the lower 16 bits for convenience
+    ; --  like RDTIM() but only returning the lower 16 bits in AY for convenience
     %asm {{
         phx
         jsr  c64.RDTIM
@@ -87,17 +84,6 @@ asmsub RDTIM16() -> uword @AY {
     }}
 }
 
-asmsub MEMTOP2() -> ubyte @A {
-    ; -- uses MEMTOP's cx16 extension to query the number of available RAM banks.
-    %asm {{
-        phx
-        sec
-        jsr  c64.MEMTOP
-        plx
-        rts
-    }}
-}
-
 }
 
 cx16 {
@@ -127,6 +113,41 @@ cx16 {
     &uword r14 = $001e
     &uword r15 = $0020
 
+    &ubyte r0L  = $0002
+    &ubyte r1L  = $0004
+    &ubyte r2L  = $0006
+    &ubyte r3L  = $0008
+    &ubyte r4L  = $000a
+    &ubyte r5L  = $000c
+    &ubyte r6L  = $000e
+    &ubyte r7L  = $0010
+    &ubyte r8L  = $0012
+    &ubyte r9L  = $0014
+    &ubyte r10L = $0016
+    &ubyte r11L = $0018
+    &ubyte r12L = $001a
+    &ubyte r13L = $001c
+    &ubyte r14L = $001e
+    &ubyte r15L = $0020
+
+    &ubyte r0H  = $0003
+    &ubyte r1H  = $0005
+    &ubyte r2H  = $0007
+    &ubyte r3H  = $0009
+    &ubyte r4H  = $000b
+    &ubyte r5H  = $000d
+    &ubyte r6H  = $000f
+    &ubyte r7H  = $0011
+    &ubyte r8H  = $0013
+    &ubyte r9H  = $0015
+    &ubyte r10H = $0017
+    &ubyte r11H = $0019
+    &ubyte r12H = $001b
+    &ubyte r13H = $001d
+    &ubyte r14H = $001f
+    &ubyte r15H = $0021
+
+
 ; VERA registers
 
     const uword VERA_BASE       = $9F20
@@ -172,7 +193,7 @@ cx16 {
 
 ; I/O
 
-    const uword  via1   = $9f60                  ;VIA 6522 #1
+    const uword  via1   = $9f00                  ;VIA 6522 #1
     &ubyte  d1prb	= via1+0
     &ubyte  d1pra	= via1+1
     &ubyte  d1ddrb	= via1+2
@@ -190,7 +211,7 @@ cx16 {
     &ubyte  d1ier	= via1+14
     &ubyte  d1ora	= via1+15
 
-    const uword  via2   = $9f70                  ;VIA 6522 #2
+    const uword  via2   = $9f10                  ;VIA 6522 #2
     &ubyte  d2prb	= via2+0
     &ubyte  d2pra	= via2+1
     &ubyte  d2ddrb	= via2+2
@@ -208,6 +229,11 @@ cx16 {
     &ubyte  d2ier	= via2+14
     &ubyte  d2ora	= via2+15
 
+    &ubyte  ym2151adr	= $9f40
+    &ubyte  ym2151dat	= $9f41
+
+    const uword  extdev	= $9f60
+
 
 ; ---- Commander X-16 additions on top of C64 kernal routines ----
 ; spelling of the names is taken from the Commander X-16 rom sources
@@ -294,16 +320,25 @@ romsub $fecc = monitor()  clobbers(A,X,Y)
 inline asmsub rombank(ubyte rombank @A) {
     ; -- set the rom banks
     %asm {{
-        sta  $01            ; rom bank register (new)
-        sta  cx16.d1prb     ; rom bank register (old)
+        sta  $01            ; rom bank register (v39+, used to be cx16.d1prb $9f60 in v38)
     }}
 }
 
 inline asmsub rambank(ubyte rambank @A) {
     ; -- set the ram bank
     %asm {{
-        sta  $00            ; ram bank register (new)
-        sta  cx16.d1pra     ; ram bank register (old)
+        sta  $00            ; ram bank register (v39+, used to be cx16.d1pra $9f61 in v38)
+    }}
+}
+
+asmsub numbanks() -> ubyte @A {
+    ; -- uses MEMTOP's cx16 extension to query the number of available RAM banks. (each is 8 Kb)
+    %asm {{
+        phx
+        sec
+        jsr  c64.MEMTOP
+        plx
+        rts
     }}
 }
 
@@ -458,6 +493,17 @@ asmsub vload(str name @R0, ubyte device @Y, ubyte bank @A, uword address @R1) ->
     }}
 }
 
+inline asmsub joystick_get2(ubyte joynr @A) clobbers(Y) -> uword @AX  {
+    ; convenience routine to get the joystick state without requiring inline assembly that deals with the multiple return values.
+    ; Also disables interrupts to avoid the IRQ race condition mentioned here: https://github.com/commanderx16/x16-rom/issues/203
+    ; TODO once that issue is resolved, this routine can be redefined as:  romsub $ff56 = joystick_get2(ubyte joynr @A) clobbers(Y) -> uword @AX
+    %asm {{
+        sei
+        jsr  cx16.joystick_get
+        cli
+    }}
+}
+
 
 sub FB_set_pixels_from_buf(uword buffer, uword count) {
     %asm {{
@@ -500,11 +546,9 @@ asmsub  init_system()  {
     %asm {{
         sei
         cld
-        ;stz  $00
-        ;stz  $01
-        ;stz  d1prb      ; select rom bank 0 (enable kernal)
         lda  #$80
         sta  VERA_CTRL
+        stz  $01        ; select rom bank 0 (enable kernal)
         jsr  c64.IOINIT
         jsr  c64.RESTOR
         jsr  c64.CINT
@@ -704,23 +748,37 @@ sys {
 
 
     asmsub reset_system() {
-        ; Soft-reset the system back to Basic prompt.
+        ; Soft-reset the system back to initial power-on Basic prompt.
         %asm {{
             sei
-            stz  $01            ; bank the kernal in (new rom bank register)
-            stz  cx16.d1prb     ; bank the kernal in (old rom bank register)
+            stz  $01            ; bank the kernal in
             jmp  (cx16.RESET_VEC)
         }}
     }
 
-    sub wait(uword jiffies) {
-        ; --- wait approximately the given number of jiffies (1/60th seconds)
-        repeat jiffies {
-            ubyte jiff = lsb(c64.RDTIM16())
-            while jiff==lsb(c64.RDTIM16()) {
-                ; wait until 1 jiffy has passed
-            }
-        }
+    asmsub wait(uword jiffies @AY) {
+        ; --- wait approximately the given number of jiffies (1/60th seconds) (N or N+1)
+        ;     note: regular system vsync irq handler must be running, and no nother irqs
+        %asm {{
+-           wai             ; wait for irq (assume it was vsync)
+            cmp  #0
+            bne  +
+            dey
++           dec  a
+            bne  -
+            cpy  #0
+            bne  -
+            rts
+        }}
+    }
+
+    inline asmsub waitvsync()  {
+        ; --- suspend execution until the next vsync has occurred, without depending on custom irq handling.
+        ;     note: system vsync irq handler has to be active for this routine to work (and no other irqs-- which is the default).
+        ;     note: a more accurate way to wait for vsync is to set up a vsync irq handler instead.
+        %asm {{
+            wai
+        }}
     }
 
     inline asmsub memcopy(uword source @R0, uword target @R1, uword count @AY) clobbers(A,X,Y) {

compiler/res/prog8lib/cx16/textio.p8

@@ -4,7 +4,6 @@
 ;
 ; indent format: TABS, size=8
 
-%target cx16
 %import syslib
 %import conv
 

compiler/res/prog8lib/diskio.p8

@@ -336,6 +336,45 @@ _end        rts
     }
 
 
+    ; ----- iterative file saver functions (uses io channel 14) -----
+
+    sub f_open_w(ubyte drivenumber, uword filenameptr) -> ubyte {
+        ; -- open a file for iterative writing with f_write
+        f_close_w()
+
+        c64.SETNAM(string.length(filenameptr), filenameptr)
+        c64.SETLFS(14, drivenumber, 1)
+        void c64.OPEN()          ; open 14,8,1,"filename"
+        if_cc {
+            void c64.CHKOUT(14)        ; use #14 as input channel
+            return not c64.READST()
+        }
+        f_close_w()
+        return false
+    }
+
+    sub f_write(uword bufferpointer, uword num_bytes) -> ubyte {
+        ; -- write the given umber of bytes to the currently open file
+        if num_bytes!=0 {
+            void c64.CHKOUT(14)        ; use #14 as input channel again
+            repeat num_bytes {
+                c64.CHROUT(@(bufferpointer))
+                bufferpointer++
+            }
+            return not c64.READST()
+        }
+        return true
+    }
+
+    sub f_close_w() {
+        ; -- end an iterative file writing session (close channels).
+        c64.CLRCHN()
+        c64.CLOSE(14)
+    }
+
+
+    ; ---- other functions ----
+
     sub status(ubyte drivenumber) -> uword {
         ; -- retrieve the disk drive's current status message
         uword messageptr = &filename
@@ -353,18 +392,22 @@ _end        rts
             messageptr++
         }
 
-io_error:
         @(messageptr) = 0
+done:
         c64.CLRCHN()        ; restore default i/o devices
         c64.CLOSE(15)
         return filename
-    }
 
+io_error:
+        filename = "?disk error"
+        goto done
+    }
 
     sub save(ubyte drivenumber, uword filenameptr, uword address, uword size) -> ubyte {
         c64.SETNAM(string.length(filenameptr), filenameptr)
         c64.SETLFS(1, drivenumber, 0)
         uword end_address = address + size
+        first_byte = 0      ; result var reuse
 
         %asm {{
             lda  address
@@ -381,7 +424,6 @@ io_error:
             plp
         }}
 
-        first_byte = 0      ; result var reuse
         if_cc
             first_byte = c64.READST()==0
 

compiler/res/prog8lib/math.asm

@@ -244,25 +244,6 @@ randseed	.proc
 		.pend
 
 
-fast_randbyte	.proc
-	; -- fast but bad 8-bit pseudo random number generator into A
-		lda  _seed
-		beq  _eor
-		asl  a
-		beq  _done	; if the input was $80, skip the EOR
-		bcc  _done
-_eor		eor  #$1d	; xor with magic value see below for possible values
-_done		sta  _seed
-		rts
-
-_seed		.byte  $3a
-
-		; possible 'magic' eor bytes are:
-		; $1d, $2b, $2d, $4d, $5f, $63, $65, $69
-		; $71, $87, $8d, $a9, $c3, $cf, $e7, $f5
-
-		.pend
-
 randbyte        .proc
 	; -- 8 bit pseudo random number generator into A (by just reusing randword)
 		jmp  randword
@@ -271,45 +252,37 @@ randbyte        .proc
 randword	.proc
 	; -- 16 bit pseudo random number generator into AY
 
-magic_eor = $3f1d
-		; possible magic eor words are:
-		; $3f1d, $3f81, $3fa5, $3fc5, $4075, $409d, $40cd, $4109
- 		; $413f, $414b, $4153, $4159, $4193, $4199, $41af, $41bb
+		; rand64k       ;Factors of 65535: 3 5 17 257
+		lda sr1+1
+		asl a
+		asl a
+		eor sr1+1
+		asl a
+		eor sr1+1
+		asl a
+		asl a
+		eor sr1+1
+		asl a
+		rol sr1         ;shift this left, "random" bit comes from low
+		rol sr1+1
+		; rand32k       ;Factors of 32767: 7 31 151 are independent and can be combined
+		lda sr2+1
+		asl a
+		eor sr2+1
+		asl a
+		asl a
+		ror sr2         ;shift this right, random bit comes from high - nicer when eor with sr1
+		rol sr2+1
+		lda sr1+1         ;can be left out
+		eor sr2+1         ;if you dont use
+		tay               ;y as suggested
+		lda sr1           ;mix up lowbytes of SR1
+		eor sr2           ;and SR2 to combine both
+		rts
 
-		lda  _seed
-		beq  _lowZero	; $0000 and $8000 are special values to test for
+sr1     	.word $a55a
+sr2     	.word $7653
 
- 		; Do a normal shift
-		asl  _seed
-		lda  _seed+1
-		rol  a
-		bcc  _noEor
-
-_doEor		; high byte is in A
-		eor  #>magic_eor
-  		sta  _seed+1
-  		lda  _seed
-  		eor  #<magic_eor
-  		sta  _seed
-  		ldy  _seed+1
-  		rts
-
-_lowZero	lda  _seed+1
-		beq  _doEor	; High byte is also zero, so apply the EOR
-				; For speed, you could store 'magic' into 'seed' directly
-				; instead of running the EORs
-
- 		; wasn't zero, check for $8000
-		asl  a
-		beq  _noEor	; if $00 is left after the shift, then it was $80
-		bcs  _doEor	; else, do the EOR based on the carry bit as usual
-
-_noEor		sta  _seed+1
-		tay
-		lda  _seed
- 		rts
-
-_seed		.word	$2c9e
 		.pend
 
 
@@ -801,6 +774,13 @@ stack_mul_word_320	.proc
 		rts
 		.pend
 
+stack_mul_word_640	.proc
+		; stackW = (stackLo * 2 * 320)    (stackHi doesn't matter)
+		asl  P8ESTACK_LO+1,x
+		jmp  stack_mul_word_320
+		.pend
+
+
 ; ----------- optimized multiplications (in-place A (byte) and ?? (word)) : ---------
 mul_byte_3	.proc
 		; A = A + A*2
@@ -1291,6 +1271,13 @@ mul_word_320	.proc
 		rts
 		.pend
 
+mul_word_640	.proc
+		; AY = (A * 2 * 320) (msb in Y doesn't matter)
+		asl  a
+		jmp  mul_word_320
+		.pend
+
+
 ; ----------- end optimized multiplications -----------
 
 

compiler/res/prog8lib/math.p8

@@ -3,5 +3,5 @@
 ; Written by Irmen de Jong (irmen@razorvine.net) - license: GNU GPL 3.0
 
 math {
-	%asminclude "library:math.asm", ""
+	%asminclude "library:math.asm"
 }

compiler/res/prog8lib/prog8_funcs.asm

@@ -387,14 +387,6 @@ func_sqrt16_into_A	.proc
 		rts
 		.pend
 
-func_fastrnd8_stack	.proc
-	; -- put a random ubyte on the estack (using fast but bad RNG)
-		jsr  math.fast_randbyte
-		sta  P8ESTACK_LO,x
-		dex
-		rts
-		.pend
-
 func_rnd_stack	.proc
 	; -- put a random ubyte on the estack
 		jsr  math.randbyte

compiler/res/prog8lib/prog8_lib.p8

@@ -3,8 +3,8 @@
 ; Written by Irmen de Jong (irmen@razorvine.net) - license: GNU GPL 3.0
 
 prog8_lib {
-	%asminclude "library:prog8_lib.asm", ""
-	%asminclude "library:prog8_funcs.asm", ""
+	%asminclude "library:prog8_lib.asm"
+	%asminclude "library:prog8_funcs.asm"
 
 	uword @zp retval_interm_uw      ; to store intermediary expression results for return values (hopefully allocated on ZP to reduce code size)
 	word @zp retval_interm_w        ; to store intermediary expression results for return values (hopefully allocated on ZP to reduce code size)

compiler/res/prog8lib/string.p8

@@ -178,7 +178,7 @@ _found		sty  P8ZP_SCRATCH_B1
 
     asmsub compare(uword string1 @R0, uword string2 @AY) clobbers(Y) -> byte @A {
         ; Compares two strings for sorting.
-        ; Returns -1 (255), 0 or 1 depeding on wether string1 sorts before, equal or after string2.
+        ; Returns -1 (255), 0 or 1 depending on wether string1 sorts before, equal or after string2.
         ; Note that you can also directly compare strings and string values with eachother using
         ; comparison operators ==, < etcetera (it will use strcmp for you under water automatically).
         %asm {{
@@ -190,8 +190,8 @@ _found		sty  P8ZP_SCRATCH_B1
         }}
     }
 
-    asmsub lower(uword st @AY) {
-        ; Lowercases the petscii string in-place.
+    asmsub lower(uword st @AY) -> ubyte @Y {
+        ; Lowercases the petscii string in-place. Returns length of the string.
         ; (for efficiency, non-letter characters > 128 will also not be left intact,
         ;  but regular text doesn't usually contain those characters anyway.)
         %asm {{
@@ -213,8 +213,8 @@ _done       rts
         }}
     }
 
-    asmsub upper(uword st @AY) {
-        ; Uppercases the petscii string in-place.
+    asmsub upper(uword st @AY) -> ubyte @Y {
+        ; Uppercases the petscii string in-place. Returns length of the string.
         %asm {{
             sta  P8ZP_SCRATCH_W1
             sty  P8ZP_SCRATCH_W1+1

compiler/res/version.txt

@@ -1 +1 @@
-6.4
+7.1-beta

compiler/src/prog8/CompilerMain.kt

@@ -1,15 +1,13 @@
 package prog8
 
-import kotlinx.cli.ArgParser
-import kotlinx.cli.ArgType
-import kotlinx.cli.default
-import kotlinx.cli.multiple
+import kotlinx.cli.*
 import prog8.ast.base.AstException
 import prog8.compiler.CompilationResult
 import prog8.compiler.compileProgram
 import prog8.compiler.target.C64Target
 import prog8.compiler.target.Cx16Target
 import prog8.parser.ParsingFailedError
+import java.io.File
 import java.nio.file.FileSystems
 import java.nio.file.Path
 import java.nio.file.StandardWatchEventKinds
@@ -18,45 +16,55 @@ import kotlin.system.exitProcess
 
 
 fun main(args: Array<String>) {
-    printSoftwareHeader("compiler")
-
-    compileMain(args)
-}
-
-internal fun printSoftwareHeader(what: String) {
     val buildVersion = object {}.javaClass.getResource("/version.txt").readText().trim()
-    println("\nProg8 $what v$buildVersion by Irmen de Jong (irmen@razorvine.net)")
+    println("\nProg8 compiler v$buildVersion by Irmen de Jong (irmen@razorvine.net)")
     println("This software is licensed under the GNU GPL 3.0, see https://www.gnu.org/licenses/gpl.html\n")
+
+    val succes = compileMain(args)
+    if(!succes)
+        exitProcess(1)
 }
 
 
 fun pathFrom(stringPath: String, vararg rest: String): Path  = FileSystems.getDefault().getPath(stringPath, *rest)
 
 
-private fun compileMain(args: Array<String>) {
+private fun compileMain(args: Array<String>): Boolean {
     val cli = ArgParser("prog8compiler", prefixStyle = ArgParser.OptionPrefixStyle.JVM)
-    val startEmulator by cli.option(ArgType.Boolean, fullName = "emu", description = "auto-start emulator after successful compilation")
+    val startEmulator1 by cli.option(ArgType.Boolean, fullName = "emu", description = "auto-start emulator after successful compilation")
+    val startEmulator2 by cli.option(ArgType.Boolean, fullName = "emu2", description = "auto-start alternative emulator after successful compilation")
     val outputDir by cli.option(ArgType.String, fullName = "out", description = "directory for output files instead of current directory").default(".")
     val dontWriteAssembly by cli.option(ArgType.Boolean, fullName = "noasm", description="don't create assembly code")
     val dontOptimize by cli.option(ArgType.Boolean, fullName = "noopt", description = "don't perform any optimizations")
     val watchMode by cli.option(ArgType.Boolean, fullName = "watch", description = "continuous compilation mode (watches for file changes), greatly increases compilation speed")
     val slowCodegenWarnings by cli.option(ArgType.Boolean, fullName = "slowwarn", description="show debug warnings about slow/problematic assembly code generation")
     val compilationTarget by cli.option(ArgType.String, fullName = "target", description = "target output of the compiler, currently '${C64Target.name}' and '${Cx16Target.name}' available").default(C64Target.name)
+    val libDirs by cli.option(ArgType.String, fullName="libdirs", description = "list of extra paths to search in for imported modules").multiple().delimiter(File.pathSeparator)
     val moduleFiles by cli.argument(ArgType.String, fullName = "modules", description = "main module file(s) to compile").multiple(999)
 
     try {
         cli.parse(args)
     } catch (e: IllegalStateException) {
         System.err.println(e.message)
-        exitProcess(1)
+        return false
     }
 
     val outputPath = pathFrom(outputDir)
     if(!outputPath.toFile().isDirectory) {
         System.err.println("Output path doesn't exist")
-        exitProcess(1)
+        return false
     }
 
+    val faultyOption = moduleFiles.firstOrNull { it.startsWith('-') }
+    if(faultyOption!=null) {
+        System.err.println("Unknown command line option given: $faultyOption")
+        return false
+    }
+
+    val libdirs = libDirs.toMutableList()
+    if(libdirs.firstOrNull()!=".")
+        libdirs.add(0, ".")
+
     if(watchMode==true) {
         val watchservice = FileSystems.getDefault().newWatchService()
         val allImportedFiles = mutableSetOf<Path>()
@@ -66,7 +74,7 @@ private fun compileMain(args: Array<String>) {
             val results = mutableListOf<CompilationResult>()
             for(filepathRaw in moduleFiles) {
                 val filepath = pathFrom(filepathRaw).normalize()
-                val compilationResult = compileProgram(filepath, dontOptimize!=true, dontWriteAssembly!=true, slowCodegenWarnings==true, compilationTarget, outputPath)
+                val compilationResult = compileProgram(filepath, dontOptimize!=true, dontWriteAssembly!=true, slowCodegenWarnings==true, compilationTarget, libdirs, outputPath)
                 results.add(compilationResult)
             }
 
@@ -103,22 +111,30 @@ private fun compileMain(args: Array<String>) {
             val filepath = pathFrom(filepathRaw).normalize()
             val compilationResult: CompilationResult
             try {
-                compilationResult = compileProgram(filepath, dontOptimize!=true, dontWriteAssembly!=true, slowCodegenWarnings==true, compilationTarget, outputPath)
+                compilationResult = compileProgram(filepath, dontOptimize!=true, dontWriteAssembly!=true, slowCodegenWarnings==true, compilationTarget, libdirs, outputPath)
                 if(!compilationResult.success)
-                    exitProcess(1)
+                    return false
             } catch (x: ParsingFailedError) {
-                exitProcess(1)
+                return false
             } catch (x: AstException) {
-                exitProcess(1)
+                return false
             }
 
-            if (startEmulator==true) {
-                if (compilationResult.programName.isEmpty())
+            if(startEmulator1==true || startEmulator2==true) {
+                if (compilationResult.programName.isEmpty()) {
                     println("\nCan't start emulator because no program was assembled.")
-                else {
-                    compilationResult.compTarget.machine.launchEmulator(compilationResult.programName)
+                    return true
                 }
             }
+
+            val programNameInPath = outputPath.resolve(compilationResult.programName)
+
+            if (startEmulator1==true)
+                compilationResult.compTarget.machine.launchEmulator(1, programNameInPath)
+            else if (startEmulator2==true)
+                compilationResult.compTarget.machine.launchEmulator(2, programNameInPath)
         }
     }
+
+    return true
 }

compiler/src/prog8/compiler/BeforeAsmGenerationAstChanger.kt

@@ -14,20 +14,20 @@ import prog8.compiler.target.ICompilationTarget
 
 internal class BeforeAsmGenerationAstChanger(val program: Program, val errors: IErrorReporter, private val compTarget: ICompilationTarget) : AstWalker() {
 
-    private val noModifications = emptyList<IAstModification>()
-
     override fun after(decl: VarDecl, parent: Node): Iterable<IAstModification> {
         subroutineVariables.add(decl.name to decl)
         if (decl.value == null && !decl.autogeneratedDontRemove && decl.type == VarDeclType.VAR && decl.datatype in NumericDatatypes) {
-            // a numeric vardecl without an initial value is initialized with zero,
-            // unless there's already an assignment below, that initializes the value
+            // A numeric vardecl without an initial value is initialized with zero,
+            // unless there's already an assignment below, that initializes the value.
+            // This allows you to restart the program and have the same starting values of the variables
             if(decl.allowInitializeWithZero)
             {
-                val nextAssign = decl.definingScope().nextSibling(decl) as? Assignment
-                if (nextAssign != null && nextAssign.target.isSameAs(IdentifierReference(listOf(decl.name), Position.DUMMY)))
+                val nextAssign = decl.definingScope.nextSibling(decl) as? Assignment
+                if (nextAssign != null && nextAssign.target isSameAs IdentifierReference(listOf(decl.name), Position.DUMMY))
                     decl.value = null
-                else
+                else {
                     decl.value = decl.zeroElementValue()
+                }
             }
         }
         return noModifications
@@ -51,14 +51,14 @@ internal class BeforeAsmGenerationAstChanger(val program: Program, val errors: I
                             // use the other part of the expression to split.
                             val assignRight = Assignment(assignment.target, binExpr.right, assignment.position)
                             return listOf(
-                                    IAstModification.InsertBefore(assignment, assignRight, assignment.definingScope()),
+                                    IAstModification.InsertBefore(assignment, assignRight, assignment.definingScope),
                                     IAstModification.ReplaceNode(binExpr.right, binExpr.left, binExpr),
                                     IAstModification.ReplaceNode(binExpr.left, assignment.target.toExpression(), binExpr))
                         }
                     } else {
                         val assignLeft = Assignment(assignment.target, binExpr.left, assignment.position)
                         return listOf(
-                                IAstModification.InsertBefore(assignment, assignLeft, assignment.definingScope()),
+                                IAstModification.InsertBefore(assignment, assignLeft, assignment.definingScope),
                                 IAstModification.ReplaceNode(binExpr.left, assignment.target.toExpression(), binExpr))
                     }
                 }
@@ -68,30 +68,37 @@ internal class BeforeAsmGenerationAstChanger(val program: Program, val errors: I
     }
 
     private val subroutineVariables = mutableListOf<Pair<String, VarDecl>>()
+    private val addedIfConditionVars = mutableSetOf<Pair<Subroutine, String>>()
 
     override fun before(subroutine: Subroutine, parent: Node): Iterable<IAstModification> {
         subroutineVariables.clear()
+        addedIfConditionVars.clear()
         return noModifications
     }
 
     override fun after(scope: AnonymousScope, parent: Node): Iterable<IAstModification> {
-        val decls = scope.statements.filterIsInstance<VarDecl>()
+        val decls = scope.statements.filterIsInstance<VarDecl>().filter { it.type == VarDeclType.VAR }
         subroutineVariables.addAll(decls.map { it.name to it })
 
-        val sub = scope.definingSubroutine()
+        val sub = scope.definingSubroutine
         if (sub != null) {
-            // move vardecls of the scope into the upper scope. Make sure the position remains the same!
-            val numericVarsWithValue = decls.filter { it.value != null && it.datatype in NumericDatatypes }
-            val replaceVardecls =numericVarsWithValue.map {
-                val initValue = it.value!!  // assume here that value has always been set by now
-                it.value = null     // make sure no value init assignment for this vardecl will be created later (would be superfluous)
-                val target = AssignTarget(IdentifierReference(listOf(it.name), it.position), null, null, it.position)
-                val assign = Assignment(target, initValue, it.position)
-                initValue.parent = assign
-                IAstModification.ReplaceNode(it, assign, scope)
+            // move any remaining vardecls of the scope into the upper scope. Make sure the position remains the same!
+            val replacements = mutableListOf<IAstModification>()
+            val movements = mutableListOf<IAstModification.InsertFirst>()
+
+            for(decl in decls) {
+                if(decl.value!=null && decl.datatype in NumericDatatypes) {
+                    val target = AssignTarget(IdentifierReference(listOf(decl.name), decl.position), null, null, decl.position)
+                    val assign = Assignment(target, decl.value!!, decl.position)
+                    replacements.add(IAstModification.ReplaceNode(decl, assign, scope))
+                    decl.value = null
+                    decl.allowInitializeWithZero = false
+                } else {
+                    replacements.add(IAstModification.Remove(decl, scope))
+                }
+                movements.add(IAstModification.InsertFirst(decl, sub))
             }
-            val moveVardeclsUp = decls.map { IAstModification.InsertFirst(it, sub) }
-            return replaceVardecls + moveVardeclsUp
+            return replacements + movements
         }
         return noModifications
     }
@@ -122,7 +129,7 @@ internal class BeforeAsmGenerationAstChanger(val program: Program, val errors: I
         }
 
         // precede a subroutine with a return to avoid falling through into the subroutine from code above it
-        val outerScope = subroutine.definingScope()
+        val outerScope = subroutine.definingScope
         val outerStatements = outerScope.statements
         val subroutineStmtIdx = outerStatements.indexOf(subroutine)
         if (subroutineStmtIdx > 0
@@ -139,7 +146,7 @@ internal class BeforeAsmGenerationAstChanger(val program: Program, val errors: I
         // see if we can remove superfluous typecasts (outside of expressions)
         // such as casting byte<->ubyte,  word<->uword
         // Also the special typecast of a reference type (str, array) to an UWORD will be changed into address-of.
-        val sourceDt = typecast.expression.inferType(program).typeOrElse(DataType.STRUCT)
+        val sourceDt = typecast.expression.inferType(program).getOr(DataType.UNDEFINED)
         if (typecast.type in ByteDatatypes && sourceDt in ByteDatatypes
                 || typecast.type in WordDatatypes && sourceDt in WordDatatypes) {
             if(typecast.parent !is Expression) {
@@ -185,9 +192,55 @@ internal class BeforeAsmGenerationAstChanger(val program: Program, val errors: I
             val booleanExpr = BinaryExpression(ifStatement.condition, "!=", NumericLiteralValue.optimalInteger(0, ifStatement.condition.position), ifStatement.condition.position)
             return listOf(IAstModification.ReplaceNode(ifStatement.condition, booleanExpr, ifStatement))
         }
+
+        if((binExpr.operator=="==" || binExpr.operator=="!=") &&
+            (binExpr.left as? NumericLiteralValue)?.number==0 &&
+            (binExpr.right as? NumericLiteralValue)?.number!=0)
+            throw CompilerException("if 0==X should have been swapped to if X==0")
+
+        // split the conditional expression into separate variables if the operand(s) is not simple.
+        // DISABLED FOR NOW AS IT GENEREATES LARGER CODE IN THE SIMPLE CASES LIKE    IF X {...}  or  IF NOT X {...}
+//        val modifications = mutableListOf<IAstModification>()
+//        if(!binExpr.left.isSimple) {
+//            val sub = binExpr.definingSubroutine()!!
+//            val (variable, isNew, assignment) = addIfOperandVar(sub, "left", binExpr.left)
+//            if(isNew)
+//                modifications.add(IAstModification.InsertFirst(variable, sub))
+//            modifications.add(IAstModification.InsertBefore(ifStatement, assignment, parent as INameScope))
+//            modifications.add(IAstModification.ReplaceNode(binExpr.left, IdentifierReference(listOf(variable.name), binExpr.position), binExpr))
+//            addedIfConditionVars.add(Pair(sub, variable.name))
+//        }
+//        if(!binExpr.right.isSimple) {
+//            val sub = binExpr.definingSubroutine()!!
+//            val (variable, isNew, assignment) = addIfOperandVar(sub, "right", binExpr.right)
+//            if(isNew)
+//                modifications.add(IAstModification.InsertFirst(variable, sub))
+//            modifications.add(IAstModification.InsertBefore(ifStatement, assignment, parent as INameScope))
+//            modifications.add(IAstModification.ReplaceNode(binExpr.right, IdentifierReference(listOf(variable.name), binExpr.position), binExpr))
+//            addedIfConditionVars.add(Pair(sub, variable.name))
+//        }
+//        return modifications
         return noModifications
     }
 
+//    private fun addIfOperandVar(sub: Subroutine, side: String, operand: Expression): Triple<VarDecl, Boolean, Assignment> {
+//        val dt = operand.inferType(program).typeOrElse(DataType.UNDEFINED)
+//        val varname = "prog8_ifvar_${side}_${dt.name.toLowerCase()}"
+//        val tgt = AssignTarget(IdentifierReference(listOf(varname), operand.position), null, null, operand.position)
+//        val assign = Assignment(tgt, operand, operand.position)
+//        if(Pair(sub, varname) in addedIfConditionVars) {
+//            val vardecl = VarDecl(VarDeclType.VAR, dt, ZeropageWish.DONTCARE, null, varname, null, null, false, true, operand.position)
+//            return Triple(vardecl, false, assign)
+//        }
+//        val existing = sub.statements.firstOrNull { it is VarDecl && it.name == varname} as VarDecl?
+//        return if (existing == null) {
+//            val vardecl = VarDecl(VarDeclType.VAR, dt, ZeropageWish.DONTCARE, null, varname, null, null, false, true, operand.position)
+//            Triple(vardecl, true, assign)
+//        } else {
+//            Triple(existing, false, assign)
+//        }
+//    }
+
     override fun after(untilLoop: UntilLoop, parent: Node): Iterable<IAstModification> {
         val binExpr = untilLoop.condition as? BinaryExpression
         if(binExpr==null || binExpr.operator !in comparisonOperators) {
@@ -213,8 +266,8 @@ internal class BeforeAsmGenerationAstChanger(val program: Program, val errors: I
             // if the datatype of the arguments of cmp() are different, cast the byte one to word.
             val arg1 = functionCallStatement.args[0]
             val arg2 = functionCallStatement.args[1]
-            val dt1 = arg1.inferType(program).typeOrElse(DataType.STRUCT)
-            val dt2 = arg2.inferType(program).typeOrElse(DataType.STRUCT)
+            val dt1 = arg1.inferType(program).getOr(DataType.UNDEFINED)
+            val dt2 = arg2.inferType(program).getOr(DataType.UNDEFINED)
             if(dt1 in ByteDatatypes) {
                 if(dt2 in ByteDatatypes)
                     return noModifications
@@ -286,12 +339,14 @@ internal class BeforeAsmGenerationAstChanger(val program: Program, val errors: I
 
     private fun getAutoIndexerVarFor(expr: ArrayIndexedExpression): MutableList<IAstModification> {
         val modifications = mutableListOf<IAstModification>()
-        val statement = expr.containingStatement()
+        val statement = expr.containingStatement
+        val dt = expr.indexer.indexExpr.inferType(program)
+        val register = if(dt.istype(DataType.UBYTE) || dt.istype(DataType.BYTE)) "r9L" else "r9"
         // replace the indexer with just the variable (simply use a cx16 virtual register r9, that we HOPE is not used for other things in the expression...)
         // assign the indexing expression to the helper variable, but only if that hasn't been done already
-        val target = AssignTarget(IdentifierReference(listOf("cx16", "r9"), expr.indexer.position), null, null, expr.indexer.position)
+        val target = AssignTarget(IdentifierReference(listOf("cx16", register), expr.indexer.position), null, null, expr.indexer.position)
         val assign = Assignment(target, expr.indexer.indexExpr, expr.indexer.position)
-        modifications.add(IAstModification.InsertBefore(statement, assign, statement.definingScope()))
+        modifications.add(IAstModification.InsertBefore(statement, assign, statement.definingScope))
         modifications.add(IAstModification.ReplaceNode(expr.indexer.indexExpr, target.identifier!!.copy(), expr.indexer))
         return modifications
     }

compiler/src/prog8/compiler/Compiler.kt

@@ -1,5 +1,6 @@
 package prog8.compiler
 
+import com.github.michaelbull.result.*
 import prog8.ast.AstToSourceCode
 import prog8.ast.IBuiltinFunctions
 import prog8.ast.IMemSizer
@@ -16,13 +17,12 @@ import prog8.compiler.target.Cx16Target
 import prog8.compiler.target.ICompilationTarget
 import prog8.compiler.target.asmGeneratorFor
 import prog8.optimizer.*
-import prog8.parser.ModuleImporter
 import prog8.parser.ParsingFailedError
-import prog8.parser.moduleName
+import prog8.parser.SourceCode.Companion.libraryFilePrefix
 import java.io.File
-import java.io.InputStream
 import java.nio.file.Path
-import kotlin.system.exitProcess
+import kotlin.io.path.Path
+import kotlin.io.path.nameWithoutExtension
 import kotlin.system.measureTimeMillis
 
 
@@ -70,6 +70,7 @@ fun compileProgram(filepath: Path,
                    writeAssembly: Boolean,
                    slowCodegenWarnings: Boolean,
                    compilationTarget: String,
+                   libdirs: List<String>,
                    outputDir: Path): CompilationResult {
     var programName = ""
     lateinit var programAst: Program
@@ -80,29 +81,34 @@ fun compileProgram(filepath: Path,
         when(compilationTarget) {
             C64Target.name -> C64Target
             Cx16Target.name -> Cx16Target
-            else -> {
-                System.err.println("invalid compilation target")
-                exitProcess(1)
-            }
+            else -> throw IllegalArgumentException("invalid compilation target")
         }
 
     try {
         val totalTime = measureTimeMillis {
             // import main module and everything it needs
-            val (ast, compilationOptions, imported) = parseImports(filepath, errors, compTarget)
+            val (ast, compilationOptions, imported) = parseImports(filepath, errors, compTarget, libdirs)
             compilationOptions.slowCodegenWarnings = slowCodegenWarnings
             compilationOptions.optimize = optimize
             programAst = ast
             importedFiles = imported
             processAst(programAst, errors, compilationOptions)
             if (compilationOptions.optimize)
-                optimizeAst(programAst, errors, BuiltinFunctionsFacade(BuiltinFunctions), compTarget)
+                optimizeAst(programAst, errors, BuiltinFunctionsFacade(BuiltinFunctions), compTarget, compilationOptions)
             postprocessAst(programAst, errors, compilationOptions)
 
             // printAst(programAst)
 
-            if(writeAssembly)
-                programName = writeAssembly(programAst, errors, outputDir, compilationOptions)
+            if(writeAssembly) {
+                val result = writeAssembly(programAst, errors, outputDir, compilationOptions)
+                when(result) {
+                    is WriteAssemblyResult.Ok -> programName = result.filename
+                    is WriteAssemblyResult.Fail -> {
+                        System.err.println(result.error)
+                        return CompilationResult(false, programAst, programName, compTarget, importedFiles)
+                    }
+                }
+            }
         }
         System.out.flush()
         System.err.flush()
@@ -131,7 +137,7 @@ fun compileProgram(filepath: Path,
         throw x
     }
 
-    val failedProgram = Program("failed", mutableListOf(), BuiltinFunctionsFacade(BuiltinFunctions), compTarget)
+    val failedProgram = Program("failed", BuiltinFunctionsFacade(BuiltinFunctions), compTarget)
     return CompilationResult(false, failedProgram, programName, compTarget, emptyList())
 }
 
@@ -165,87 +171,106 @@ private class BuiltinFunctionsFacade(functions: Map<String, FSignature>): IBuilt
         builtinFunctionReturnType(name, args, program)
 }
 
-private fun parseImports(filepath: Path, errors: IErrorReporter, compTarget: ICompilationTarget): Triple<Program, CompilationOptions, List<Path>> {
-    val compilationTargetName = compTarget.name
-    println("Compiler target: $compilationTargetName. Parsing...")
-    val importer = ModuleImporter()
+fun parseImports(filepath: Path,
+                         errors: IErrorReporter,
+                         compTarget: ICompilationTarget,
+                         libdirs: List<String>): Triple<Program, CompilationOptions, List<Path>> {
+    println("Compiler target: ${compTarget.name}. Parsing...")
     val bf = BuiltinFunctionsFacade(BuiltinFunctions)
-    val programAst = Program(moduleName(filepath.fileName), mutableListOf(), bf, compTarget)
+    val programAst = Program(filepath.nameWithoutExtension, bf, compTarget)
     bf.program = programAst
-    importer.importModule(programAst, filepath, compTarget, compilationTargetName)
+
+    val importer = ModuleImporter(programAst, compTarget.name, errors, libdirs)
+    val importedModuleResult = importer.importModule(filepath)
+    importedModuleResult.onFailure { throw it }
     errors.report()
 
-    val importedFiles = programAst.modules.filter { !it.source.startsWith("@embedded@") }.map { it.source }
+    val importedFiles = programAst.modules
+        .mapNotNull { it.source }
+        .filter { !it.isFromResources } // TODO: parseImports/importedFiles - maybe rather `source.isFromFilesystem`?
+        .map { Path(it.pathString()) }
     val compilerOptions = determineCompilationOptions(programAst, compTarget)
     if (compilerOptions.launcher == LauncherType.BASIC && compilerOptions.output != OutputType.PRG)
         throw ParsingFailedError("${programAst.modules.first().position} BASIC launcher requires output type PRG.")
 
     // depending on the machine and compiler options we may have to include some libraries
-    for(lib in compTarget.machine.importLibs(compilerOptions, compilationTargetName))
-        importer.importLibraryModule(programAst, lib, compTarget, compilationTargetName)
+    for(lib in compTarget.machine.importLibs(compilerOptions, compTarget.name))
+        importer.importLibraryModule(lib)
 
     // always import prog8_lib and math
-    importer.importLibraryModule(programAst, "math", compTarget, compilationTargetName)
-    importer.importLibraryModule(programAst, "prog8_lib", compTarget, compilationTargetName)
+    importer.importLibraryModule("math")
+    importer.importLibraryModule("prog8_lib")
     errors.report()
     return Triple(programAst, compilerOptions, importedFiles)
 }
 
-private fun determineCompilationOptions(program: Program, compTarget: ICompilationTarget): CompilationOptions {
+fun determineCompilationOptions(program: Program, compTarget: ICompilationTarget): CompilationOptions {
     val mainModule = program.mainModule
-    val outputType = (mainModule.statements.singleOrNull { it is Directive && it.directive == "%output" }
-            as? Directive)?.args?.single()?.name?.toUpperCase()
-    val launcherType = (mainModule.statements.singleOrNull { it is Directive && it.directive == "%launcher" }
-            as? Directive)?.args?.single()?.name?.toUpperCase()
+    val outputDirective = (mainModule.statements.singleOrNull { it is Directive && it.directive == "%output" } as? Directive)
+    val launcherDirective = (mainModule.statements.singleOrNull { it is Directive && it.directive == "%launcher" } as? Directive)
+    val outputTypeStr = outputDirective?.args?.single()?.name?.uppercase()
+    val launcherTypeStr = launcherDirective?.args?.single()?.name?.uppercase()
     val zpoption: String? = (mainModule.statements.singleOrNull { it is Directive && it.directive == "%zeropage" }
-            as? Directive)?.args?.single()?.name?.toUpperCase()
-    val allOptions = program.modules.flatMap { it.statements }.filter { it is Directive && it.directive == "%option" }.flatMap { (it as Directive).args }.toSet()
+            as? Directive)?.args?.single()?.name?.uppercase()
+    val allOptions = program.modules.flatMap { it.statements }.filter { it is Directive && it.directive == "%option" }
+        .flatMap { (it as Directive).args }.toSet()
     val floatsEnabled = allOptions.any { it.name == "enable_floats" }
     val noSysInit = allOptions.any { it.name == "no_sysinit" }
     var zpType: ZeropageType =
-            if (zpoption == null)
-                if(floatsEnabled) ZeropageType.FLOATSAFE else ZeropageType.KERNALSAFE
-            else
-                try {
-                    ZeropageType.valueOf(zpoption)
-                } catch (x: IllegalArgumentException) {
-                    ZeropageType.KERNALSAFE
-                    // error will be printed by the astchecker
-                }
+        if (zpoption == null)
+            if (floatsEnabled) ZeropageType.FLOATSAFE else ZeropageType.KERNALSAFE
+        else
+            try {
+                ZeropageType.valueOf(zpoption)
+            } catch (x: IllegalArgumentException) {
+                ZeropageType.KERNALSAFE
+                // error will be printed by the astchecker
+            }
 
-    if (zpType==ZeropageType.FLOATSAFE && compTarget.name == Cx16Target.name) {
-        System.err.println("Warning: Cx16 target must use zp option basicsafe instead of floatsafe")
+    if (zpType == ZeropageType.FLOATSAFE && compTarget.name == Cx16Target.name) {
+        System.err.println("Warning: zp option floatsafe changed to basicsafe for cx16 target")
         zpType = ZeropageType.BASICSAFE
     }
 
     val zpReserved = mainModule.statements
-            .asSequence()
-            .filter { it is Directive && it.directive == "%zpreserved" }
-            .map { (it as Directive).args }
-            .map { it[0].int!!..it[1].int!! }
-            .toList()
+        .asSequence()
+        .filter { it is Directive && it.directive == "%zpreserved" }
+        .map { (it as Directive).args }
+        .map { it[0].int!!..it[1].int!! }
+        .toList()
 
-    if(outputType!=null && !OutputType.values().any {it.name==outputType}) {
-        System.err.println("invalid output type $outputType")
-        exitProcess(1)
+    val outputType = if (outputTypeStr == null) OutputType.PRG else {
+        try {
+            OutputType.valueOf(outputTypeStr)
+        } catch (x: IllegalArgumentException) {
+            // set default value; actual check and error handling of invalid option is handled in the AstChecker later
+            OutputType.PRG
+        }
     }
-    if(launcherType!=null && !LauncherType.values().any {it.name==launcherType}) {
-        System.err.println("invalid launcher type $launcherType")
-        exitProcess(1)
+    val launcherType = if (launcherTypeStr == null) LauncherType.BASIC else {
+        try {
+            LauncherType.valueOf(launcherTypeStr)
+        } catch (x: IllegalArgumentException) {
+            // set default value; actual check and error handling of invalid option is handled in the AstChecker later
+            LauncherType.BASIC
+        }
     }
 
     return CompilationOptions(
-            if (outputType == null) OutputType.PRG else OutputType.valueOf(outputType),
-            if (launcherType == null) LauncherType.BASIC else LauncherType.valueOf(launcherType),
-            zpType, zpReserved, floatsEnabled, noSysInit,
-            compTarget
+        outputType,
+        launcherType,
+        zpType, zpReserved, floatsEnabled, noSysInit,
+        compTarget
     )
 }
 
 private fun processAst(programAst: Program, errors: IErrorReporter, compilerOptions: CompilationOptions) {
     // perform initial syntax checks and processings
     println("Processing for target ${compilerOptions.compTarget.name}...")
-    programAst.checkIdentifiers(errors, compilerOptions.compTarget)
+    programAst.checkIdentifiers(errors, compilerOptions)
+    errors.report()
+    // TODO: turning char literals into UBYTEs via an encoding should really happen in code gen - but for that we'd need DataType.CHAR
+    programAst.charLiteralsToUByteLiterals(errors, compilerOptions.compTarget)
     errors.report()
     programAst.constantFold(errors, compilerOptions.compTarget)
     errors.report()
@@ -253,50 +278,58 @@ private fun processAst(programAst: Program, errors: IErrorReporter, compilerOpti
     errors.report()
     programAst.addTypecasts(errors)
     errors.report()
-    programAst.variousCleanups()
+    programAst.variousCleanups(programAst, errors)
+    errors.report()
     programAst.checkValid(compilerOptions, errors, compilerOptions.compTarget)
     errors.report()
-    programAst.checkIdentifiers(errors, compilerOptions.compTarget)
+    programAst.checkIdentifiers(errors, compilerOptions)
     errors.report()
 }
 
-private fun optimizeAst(programAst: Program, errors: IErrorReporter, functions: IBuiltinFunctions, compTarget: ICompilationTarget) {
+private fun optimizeAst(programAst: Program, errors: IErrorReporter, functions: IBuiltinFunctions, compTarget: ICompilationTarget, options: CompilationOptions) {
     // optimize the parse tree
     println("Optimizing...")
+
+    val remover = UnusedCodeRemover(programAst, errors, compTarget)
+    remover.visit(programAst)
+    remover.applyModifications()
+
     while (true) {
         // keep optimizing expressions and statements until no more steps remain
         val optsDone1 = programAst.simplifyExpressions()
         val optsDone2 = programAst.splitBinaryExpressions(compTarget)
-        val optsDone3 = programAst.optimizeStatements(errors, functions, compTarget, ::loadAsmIncludeFile)
+        val optsDone3 = programAst.optimizeStatements(errors, functions, compTarget)
         programAst.constantFold(errors, compTarget) // because simplified statements and expressions can result in more constants that can be folded away
         errors.report()
         if (optsDone1 + optsDone2 + optsDone3 == 0)
             break
     }
 
-    val remover = UnusedCodeRemover(programAst, errors, compTarget, ::loadAsmIncludeFile)
-    remover.visit(programAst)
-    remover.applyModifications()
     errors.report()
 }
 
 private fun postprocessAst(programAst: Program, errors: IErrorReporter, compilerOptions: CompilationOptions) {
     programAst.addTypecasts(errors)
     errors.report()
-    programAst.variousCleanups()
+    programAst.variousCleanups(programAst, errors)
     programAst.checkValid(compilerOptions, errors, compilerOptions.compTarget)          // check if final tree is still valid
     errors.report()
-    val callGraph = CallGraph(programAst, ::loadAsmIncludeFile)
+    val callGraph = CallGraph(programAst)
     callGraph.checkRecursiveCalls(errors)
     errors.report()
     programAst.verifyFunctionArgTypes()
     programAst.moveMainAndStartToFirst()
 }
 
+private sealed class WriteAssemblyResult {
+    class Ok(val filename: String): WriteAssemblyResult()
+    class Fail(val error: String): WriteAssemblyResult()
+}
+
 private fun writeAssembly(programAst: Program,
                           errors: IErrorReporter,
                           outputDir: Path,
-                          compilerOptions: CompilationOptions): String {
+                          compilerOptions: CompilationOptions): WriteAssemblyResult {
     // asm generation directly from the Ast
     programAst.processAstBeforeAsmGeneration(errors, compilerOptions.compTarget)
     errors.report()
@@ -310,9 +343,19 @@ private fun writeAssembly(programAst: Program,
             compilerOptions.compTarget.machine.zeropage,
             compilerOptions,
             outputDir).compileToAssembly()
-    assembly.assemble(compilerOptions)
-    errors.report()
-    return assembly.name
+
+    return if(assembly.valid && errors.noErrors()) {
+        val assemblerReturnStatus = assembly.assemble(compilerOptions)
+        if(assemblerReturnStatus!=0)
+            WriteAssemblyResult.Fail("assembler step failed with return code $assemblerReturnStatus")
+        else {
+            errors.report()
+            WriteAssemblyResult.Ok(assembly.name)
+        }
+    } else {
+        errors.report()
+        WriteAssemblyResult.Fail("compiler failed with errors")
+    }
 }
 
 fun printAst(programAst: Program) {
@@ -322,21 +365,19 @@ fun printAst(programAst: Program) {
     println()
 }
 
-fun loadAsmIncludeFile(filename: String, source: Path): String {
-    return if (filename.startsWith("library:")) {
-        val resource = tryGetEmbeddedResource(filename.substring(8))
-            ?: throw IllegalArgumentException("library file '$filename' not found")
-        resource.bufferedReader().use { it.readText() }
+internal fun loadAsmIncludeFile(filename: String, sourcePath: Path): Result<String, NoSuchFileException> {
+    return if (filename.startsWith(libraryFilePrefix)) {
+        return runCatching {
+            val stream = object {}.javaClass.getResourceAsStream("/prog8lib/${filename.substring(libraryFilePrefix.length)}") // TODO handle via SourceCode
+            stream!!.bufferedReader().use { r -> r.readText() }
+        }.mapError { NoSuchFileException(File(filename)) }
     } else {
         // first try in the isSameAs folder as where the containing file was imported from
-        val sib = source.resolveSibling(filename)
+        val sib = sourcePath.resolveSibling(filename)
+
         if (sib.toFile().isFile)
-            sib.toFile().readText()
+            Ok(sib.toFile().readText())
         else
-            File(filename).readText()
+            Ok(File(filename).readText())
     }
 }
-
-internal fun tryGetEmbeddedResource(name: String): InputStream? {
-    return object{}.javaClass.getResourceAsStream("/prog8lib/$name")
-}

compiler/src/prog8/compiler/ErrorReporting.kt

@@ -7,7 +7,7 @@ import prog8.parser.ParsingFailedError
 interface IErrorReporter {
     fun err(msg: String, position: Position)
     fun warn(msg: String, position: Position)
-    fun isEmpty(): Boolean
+    fun noErrors(): Boolean
     fun report()
 }
 
@@ -53,5 +53,5 @@ internal class ErrorReporter: IErrorReporter {
             throw ParsingFailedError("There are $numErrors errors and $numWarnings warnings.")
     }
 
-    override fun isEmpty() = messages.isEmpty()
+    override fun noErrors() = messages.none { it.severity==MessageSeverity.ERROR }
 }

compiler/src/prog8/compiler/IStringEncoding.kt

@@ -0,0 +1,6 @@
+package prog8.compiler
+
+interface IStringEncoding {
+    fun encodeString(str: String, altEncoding: Boolean): List<Short>
+    fun decodeString(bytes: List<Short>, altEncoding: Boolean): String
+}

compiler/src/prog8/compiler/ModuleImporter.kt

@@ -0,0 +1,145 @@
+package prog8.compiler
+
+import com.github.michaelbull.result.Err
+import com.github.michaelbull.result.Ok
+import com.github.michaelbull.result.Result
+import prog8.ast.Module
+import prog8.ast.Program
+import prog8.ast.base.Position
+import prog8.ast.base.SyntaxError
+import prog8.ast.statements.Directive
+import prog8.ast.statements.DirectiveArg
+import prog8.parser.Prog8Parser
+import prog8.parser.SourceCode
+import java.nio.file.Path
+import kotlin.io.path.*
+
+
+class ModuleImporter(private val program: Program,
+                     private val compilationTargetName: String,
+                     val errors: IErrorReporter,
+                     libdirs: List<String>) {
+
+    private val libpaths: List<Path> = libdirs.map { Path(it) }
+
+    fun importModule(filePath: Path): Result<Module, NoSuchFileException> {
+        val currentDir = Path("").absolute()
+        val searchIn = listOf(currentDir) + libpaths
+        val candidates = searchIn
+            .map { it.absolute().div(filePath).normalize().absolute() }
+            .filter { it.exists() }
+            .map { currentDir.relativize(it) }
+            .map { if (it.isAbsolute) it else Path(".", "$it") }
+
+        val srcPath = when (candidates.size) {
+            0 -> return Err(NoSuchFileException(
+                    file = filePath.normalize().toFile(),
+                    reason = "searched in $searchIn"))
+            1 -> candidates.first()
+            else -> candidates.first()  // TODO: report error if more than 1 candidate?
+        }
+
+        val logMsg = "importing '${filePath.nameWithoutExtension}' (from file $srcPath)"
+        println(logMsg)
+
+        return Ok(importModule(SourceCode.fromPath(srcPath)))
+    }
+
+    fun importLibraryModule(name: String): Module? {
+        val import = Directive("%import", listOf(
+                DirectiveArg("", name, 42, position = Position("<<<implicit-import>>>", 0, 0, 0))
+        ), Position("<<<implicit-import>>>", 0, 0, 0))
+        return executeImportDirective(import, null)
+    }
+
+    //private fun importModule(stream: CharStream, modulePath: Path, isLibrary: Boolean): Module {
+    private fun importModule(src: SourceCode) : Module {
+        val moduleAst = Prog8Parser.parseModule(src)
+        program.addModule(moduleAst)
+
+        // accept additional imports
+        val lines = moduleAst.statements.toMutableList()
+        lines.asSequence()
+                .mapIndexed { i, it -> i to it }
+                .filter { (it.second as? Directive)?.directive == "%import" }
+                .forEach { executeImportDirective(it.second as Directive, moduleAst) }
+
+        moduleAst.statements = lines
+        return moduleAst
+    }
+
+    private fun executeImportDirective(import: Directive, importingModule: Module?): Module? {
+        if(import.directive!="%import" || import.args.size!=1 || import.args[0].name==null)
+            throw SyntaxError("invalid import directive", import.position)
+        val moduleName = import.args[0].name!!
+        if("$moduleName.p8" == import.position.file)
+            throw SyntaxError("cannot import self", import.position)
+
+        val existing = program.modules.singleOrNull { it.name == moduleName }
+        if (existing!=null)
+            return null // TODO: why return null instead of Module instance?
+
+        var srcCode = tryGetModuleFromResource("$moduleName.p8", compilationTargetName)
+        val importedModule =
+            if (srcCode != null) {
+                println("importing '$moduleName' (from internal ${srcCode.origin})")
+                importModule(srcCode)
+            } else {
+                srcCode = tryGetModuleFromFile(moduleName, importingModule)
+                if (srcCode == null) {
+                    errors.err("imported file not found: $moduleName.p8", import.position)
+                    return null
+                    //throw NoSuchFileException(File("$moduleName.p8"))
+                }
+                importModule(srcCode)
+            }
+
+        removeDirectivesFromImportedModule(importedModule)
+        return importedModule
+    }
+
+    private fun removeDirectivesFromImportedModule(importedModule: Module) {
+        // Most global directives don't apply for imported modules, so remove them
+        val moduleLevelDirectives = listOf("%output", "%launcher", "%zeropage", "%zpreserved", "%address", "%target")
+        var directives = importedModule.statements.filterIsInstance<Directive>()
+        importedModule.statements.removeAll(directives)
+        directives = directives.filter{ it.directive !in moduleLevelDirectives }
+        importedModule.statements.addAll(0, directives)
+    }
+
+    private fun tryGetModuleFromResource(name: String, compilationTargetName: String): SourceCode? {
+        // try target speficic first
+        try {
+            return SourceCode.fromResources("/prog8lib/$compilationTargetName/$name")
+        } catch (e: FileSystemException) {
+        }
+        try {
+            return SourceCode.fromResources("/prog8lib/$name")
+        } catch (e: FileSystemException) {
+        }
+        return null
+    }
+
+    private fun tryGetModuleFromFile(name: String, importingModule: Module?): SourceCode? {
+        val fileName = "$name.p8"
+        val locations =
+            if (importingModule == null) { // <=> imported from library module
+                libpaths
+            } else {
+                libpaths.drop(1) +  // TODO: why drop the first?
+                // FIXME: won't work until Prog8Parser is fixed s.t. it fully initialzes the modules it returns
+                listOf(Path(importingModule.position.file).parent ?: Path("")) +
+                listOf(Path(".", "prog8lib"))
+            }
+
+        locations.forEach {
+            try {
+                return SourceCode.fromPath(it.resolve(fileName))
+            } catch (e: NoSuchFileException) {
+            }
+        }
+
+        //throw ParsingFailedError("$position Import: no module source file '$fileName' found  (I've looked in: embedded libs and $locations)")
+        return null
+    }
+}

compiler/src/prog8/compiler/Zeropage.kt

@@ -19,7 +19,29 @@ abstract class Zeropage(protected val options: CompilationOptions) {
 
     val allowedDatatypes = NumericDatatypes
 
-    fun available() = if(options.zeropage==ZeropageType.DONTUSE) 0 else free.size
+    fun availableBytes() = if(options.zeropage==ZeropageType.DONTUSE) 0 else free.size
+    fun hasByteAvailable() = if(options.zeropage==ZeropageType.DONTUSE) false else free.isNotEmpty()
+    fun availableWords(): Int {
+        if(options.zeropage==ZeropageType.DONTUSE)
+            return 0
+
+        val words = free.windowed(2).filter { it[0] == it[1]-1 }
+        var nonOverlappingWordsCount = 0
+        var prevMsbLoc = -1
+        for(w in words) {
+            if(w[0]!=prevMsbLoc) {
+                nonOverlappingWordsCount++
+                prevMsbLoc = w[1]
+            }
+        }
+        return nonOverlappingWordsCount
+    }
+    fun hasWordAvailable(): Boolean {
+        if(options.zeropage==ZeropageType.DONTUSE)
+            return false
+
+        return free.windowed(2).any { it[0] == it[1] - 1 }
+    }
 
     fun allocate(scopedname: String, datatype: DataType, position: Position?, errors: IErrorReporter): Int {
         assert(scopedname.isEmpty() || !allocations.values.any { it.first==scopedname } ) {"scopedname can't be allocated twice"}

compiler/src/prog8/compiler/astprocessing/AstChecker.kt

@@ -9,12 +9,14 @@ import prog8.ast.statements.*
 import prog8.ast.walk.IAstVisitor
 import prog8.compiler.CompilationOptions
 import prog8.compiler.IErrorReporter
+import prog8.compiler.ZeropageType
 import prog8.compiler.functions.BuiltinFunctions
 import prog8.compiler.functions.builtinFunctionReturnType
-import prog8.compiler.target.C64Target
-import prog8.compiler.target.Cx16Target
 import prog8.compiler.target.ICompilationTarget
+import java.io.CharConversionException
 import java.io.File
+import java.util.*
+import kotlin.io.path.*
 
 internal class AstChecker(private val program: Program,
                           private val compilerOptions: CompilationOptions,
@@ -41,6 +43,11 @@ internal class AstChecker(private val program: Program,
             }
         }
 
+        if(compilerOptions.floats) {
+            if (compilerOptions.zeropage !in setOf(ZeropageType.FLOATSAFE, ZeropageType.BASICSAFE, ZeropageType.DONTUSE ))
+                errors.err("when floats are enabled, zero page type should be 'floatsafe' or 'basicsafe' or 'dontuse'", program.mainModule.position)
+        }
+
         super.visit(program)
     }
 
@@ -56,7 +63,7 @@ internal class AstChecker(private val program: Program,
     }
 
     override fun visit(returnStmt: Return) {
-        val expectedReturnValues = returnStmt.definingSubroutine()?.returntypes ?: emptyList()
+        val expectedReturnValues = returnStmt.definingSubroutine?.returntypes ?: emptyList()
         if(expectedReturnValues.size>1) {
             throw FatalAstException("cannot use a return with one value in a subroutine that has multiple return values: $returnStmt")
         }
@@ -70,9 +77,9 @@ internal class AstChecker(private val program: Program,
         if(expectedReturnValues.size==1 && returnStmt.value!=null) {
             val valueDt = returnStmt.value!!.inferType(program)
             if(!valueDt.isKnown) {
-                errors.err("return value type mismatch", returnStmt.value!!.position)
+                errors.err("return value type mismatch or unknown symbol", returnStmt.value!!.position)
             } else {
-                if (expectedReturnValues[0] != valueDt.typeOrElse(DataType.STRUCT))
+                if (expectedReturnValues[0] != valueDt.getOr(DataType.UNDEFINED))
                     errors.err("type $valueDt of return value doesn't match subroutine's return type ${expectedReturnValues[0]}", returnStmt.value!!.position)
             }
         }
@@ -80,13 +87,25 @@ internal class AstChecker(private val program: Program,
     }
 
     override fun visit(ifStatement: IfStatement) {
-        if(ifStatement.condition.inferType(program).typeOrElse(DataType.STRUCT) !in IntegerDatatypes)
+        if(!ifStatement.condition.inferType(program).isInteger)
             errors.err("condition value should be an integer type", ifStatement.condition.position)
         super.visit(ifStatement)
     }
 
     override fun visit(forLoop: ForLoop) {
-        val iterableDt = forLoop.iterable.inferType(program).typeOrElse(DataType.BYTE)
+
+        fun checkUnsignedLoopDownto0(range: RangeExpr?) {
+            if(range==null)
+                return
+            val step = range.step.constValue(program)?.number?.toDouble() ?: 1.0
+            if(step < -1.0) {
+                val limit = range.to.constValue(program)?.number?.toDouble()
+                if(limit==0.0 && range.from.constValue(program)==null)
+                    errors.err("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", forLoop.position)
+            }
+        }
+
+        val iterableDt = forLoop.iterable.inferType(program).getOr(DataType.BYTE)
         if(iterableDt !in IterableDatatypes && forLoop.iterable !is RangeExpr) {
             errors.err("can only loop over an iterable type", forLoop.position)
         } else {
@@ -98,11 +117,15 @@ internal class AstChecker(private val program: Program,
                     DataType.UBYTE -> {
                         if(iterableDt!= DataType.UBYTE && iterableDt!= DataType.ARRAY_UB && iterableDt != DataType.STR)
                             errors.err("ubyte loop variable can only loop over unsigned bytes or strings", forLoop.position)
+
+                        checkUnsignedLoopDownto0(forLoop.iterable as? RangeExpr)
                     }
                     DataType.UWORD -> {
                         if(iterableDt!= DataType.UBYTE && iterableDt!= DataType.UWORD && iterableDt != DataType.STR &&
                                 iterableDt != DataType.ARRAY_UB && iterableDt!= DataType.ARRAY_UW)
                             errors.err("uword loop variable can only loop over unsigned bytes, words or strings", forLoop.position)
+
+                        checkUnsignedLoopDownto0(forLoop.iterable as? RangeExpr)
                     }
                     DataType.BYTE -> {
                         if(iterableDt!= DataType.BYTE && iterableDt!= DataType.ARRAY_B)
@@ -114,11 +137,14 @@ internal class AstChecker(private val program: Program,
                             errors.err("word loop variable can only loop over bytes or words", forLoop.position)
                     }
                     DataType.FLOAT -> {
+                        // Looping over float variables is very inefficient because the loopvar is going to
+                        // get copied over with new values all the time. We don't support this for now.
+                        // Loop with an integer index variable if you really need to... or write different code.
                         errors.err("for loop only supports integers", forLoop.position)
                     }
                     else -> errors.err("loop variable must be numeric type", forLoop.position)
                 }
-                if(errors.isEmpty()) {
+                if(errors.noErrors()) {
                     // check loop range values
                     val range = forLoop.iterable as? RangeExpr
                     if(range!=null) {
@@ -140,6 +166,7 @@ internal class AstChecker(private val program: Program,
         super.visit(forLoop)
     }
 
+
     override fun visit(jump: Jump) {
         val ident = jump.identifier
         if(ident!=null) {
@@ -190,6 +217,28 @@ internal class AstChecker(private val program: Program,
         super.visit(label)
     }
 
+    private fun hasReturnOrJump(scope: INameScope): Boolean {
+        class Searcher: IAstVisitor
+        {
+            var count=0
+
+            override fun visit(returnStmt: Return) {
+                count++
+            }
+            override fun visit(jump: Jump) {
+                count++
+            }
+        }
+
+        val s=Searcher()
+        for(stmt in scope.statements) {
+            stmt.accept(s)
+            if(s.count>0)
+                return true
+        }
+        return s.count > 0
+    }
+
     override fun visit(subroutine: Subroutine) {
         fun err(msg: String) = errors.err(msg, subroutine.position)
 
@@ -203,13 +252,6 @@ internal class AstChecker(private val program: Program,
         if(uniqueNames.size!=subroutine.parameters.size)
             err("parameter names must be unique")
 
-        if(subroutine.inline) {
-            if (subroutine.containsDefinedVariables())
-                err("can't inline a subroutine that defines variables")
-            if (!subroutine.isAsmSubroutine && subroutine.parameters.isNotEmpty())
-                err("can't inline a non-asm subroutine that has parameters")
-        }
-
         super.visit(subroutine)
 
         // user-defined subroutines can only have zero or one return type
@@ -219,7 +261,7 @@ internal class AstChecker(private val program: Program,
 
         // subroutine must contain at least one 'return' or 'goto'
         // (or if it has an asm block, that must contain a 'rts' or 'jmp' or 'bra')
-        if(subroutine.statements.count { it is Return || it is Jump } == 0) {
+        if(!hasReturnOrJump(subroutine)) {
             if (subroutine.amountOfRtsInAsm() == 0) {
                 if (subroutine.returntypes.isNotEmpty()) {
                     // for asm subroutines with an address, no statement check is possible.
@@ -229,10 +271,11 @@ internal class AstChecker(private val program: Program,
             }
         }
 
-        // scope check
-        if(subroutine.parent !is Block && subroutine.parent !is Subroutine) {
+        if(subroutine.inline && !subroutine.isAsmSubroutine)
+            err("subroutine inlining is currently only supported on asmsub routines")
+
+        if(subroutine.parent !is Block && subroutine.parent !is Subroutine)
             err("subroutines can only be defined in the scope of a block or within another subroutine")
-        }
 
         if(subroutine.isAsmSubroutine) {
             if(subroutine.asmParameterRegisters.size != subroutine.parameters.size)
@@ -348,13 +391,13 @@ internal class AstChecker(private val program: Program,
     }
 
     override fun visit(untilLoop: UntilLoop) {
-        if(untilLoop.condition.inferType(program).typeOrElse(DataType.STRUCT) !in IntegerDatatypes)
+        if(!untilLoop.condition.inferType(program).isInteger)
             errors.err("condition value should be an integer type", untilLoop.condition.position)
         super.visit(untilLoop)
     }
 
     override fun visit(whileLoop: WhileLoop) {
-        if(whileLoop.condition.inferType(program).typeOrElse(DataType.STRUCT) !in IntegerDatatypes)
+        if(!whileLoop.condition.inferType(program).isInteger)
             errors.err("condition value should be an integer type", whileLoop.condition.position)
         super.visit(whileLoop)
     }
@@ -374,43 +417,19 @@ internal class AstChecker(private val program: Program,
                 if(!idt.isKnown) {
                      errors.err("return type mismatch", assignment.value.position)
                 }
-                if(stmt.returntypes.isEmpty() || (stmt.returntypes.size == 1 && stmt.returntypes.single() isNotAssignableTo idt.typeOrElse(DataType.BYTE))) {
+                if(stmt.returntypes.isEmpty() || (stmt.returntypes.size == 1 && stmt.returntypes.single() isNotAssignableTo idt.getOr(DataType.BYTE))) {
                     errors.err("return type mismatch", assignment.value.position)
                 }
             }
         }
 
-        val targetIdent = assignment.target.identifier
-        if(targetIdent!=null) {
-            val targetVar = targetIdent.targetVarDecl(program)
-            if(targetVar?.struct != null) {
-                val sourceStructLv = assignment.value as? ArrayLiteralValue
-                if (sourceStructLv != null) {
-                    if (sourceStructLv.value.size != targetVar.struct?.numberOfElements)
-                        errors.err("number of elements doesn't match struct definition", sourceStructLv.position)
-                } else {
-                    val sourceIdent = assignment.value as? IdentifierReference
-                    if (sourceIdent != null) {
-                        val sourceVar = sourceIdent.targetVarDecl(program)
-                        if (sourceVar?.struct != null) {
-                            if (sourceVar.struct !== targetVar.struct)
-                                errors.err("assignment of different struct types", assignment.position)
-                        } else if(sourceVar?.isArray==true) {
-                            if((sourceVar.value as ArrayLiteralValue).value.size != targetVar.struct?.numberOfElements)
-                                errors.err("number of elements doesn't match struct definition", sourceVar.position)
-                        }
-                    }
-                }
-            }
-        }
-
         val targetDt = assignment.target.inferType(program)
         val valueDt = assignment.value.inferType(program)
         if(valueDt.isKnown && !(valueDt isAssignableTo targetDt)) {
-            if(targetDt.typeOrElse(DataType.STRUCT) in IterableDatatypes)
+            if(targetDt.isIterable)
                 errors.err("cannot assign value to string or array", assignment.value.position)
             else if(!(valueDt.istype(DataType.STR) && targetDt.istype(DataType.UWORD)))
-                errors.err("value's type doesn't match target", assignment.value.position)
+                errors.err("type of value doesn't match target", assignment.value.position)
         }
 
         if(assignment.value is TypecastExpression) {
@@ -463,15 +482,15 @@ internal class AstChecker(private val program: Program,
             if (targetDatatype.isKnown) {
                 val constVal = assignment.value.constValue(program)
                 if (constVal != null) {
-                    checkValueTypeAndRange(targetDatatype.typeOrElse(DataType.BYTE), constVal)
+                    checkValueTypeAndRange(targetDatatype.getOr(DataType.BYTE), constVal)
                 } else {
                     val sourceDatatype = assignment.value.inferType(program)
                     if (sourceDatatype.isUnknown) {
                         if (assignment.value !is FunctionCall)
                             errors.err("assignment value is invalid or has no proper datatype", assignment.value.position)
                     } else {
-                        checkAssignmentCompatible(targetDatatype.typeOrElse(DataType.BYTE), assignTarget,
-                                sourceDatatype.typeOrElse(DataType.BYTE), assignment.value, assignment.position)
+                        checkAssignmentCompatible(targetDatatype.getOr(DataType.BYTE), assignTarget,
+                                sourceDatatype.getOr(DataType.BYTE), assignment.value, assignment.position)
                     }
                 }
             }
@@ -480,12 +499,8 @@ internal class AstChecker(private val program: Program,
 
     override fun visit(addressOf: AddressOf) {
         val variable=addressOf.identifier.targetVarDecl(program)
-        if(variable!=null
-            && variable.datatype !in ArrayDatatypes
-            && variable.type!=VarDeclType.MEMORY
-            && variable.struct == null
-            && variable.datatype != DataType.STR && variable.datatype!=DataType.STRUCT)
-                errors.err("invalid pointer-of operand type", addressOf.position)
+        if(variable!=null && variable.type==VarDeclType.CONST)
+            errors.err("invalid pointer-of operand type", addressOf.position)
         super.visit(addressOf)
     }
 
@@ -527,17 +542,6 @@ internal class AstChecker(private val program: Program,
 
         when(decl.type) {
             VarDeclType.VAR, VarDeclType.CONST -> {
-                if(decl.datatype==DataType.STRUCT) {
-                    if(decl.struct==null)
-                        throw FatalAstException("struct vardecl should be linked to its struct $decl")
-                    if(decl.zeropage==ZeropageWish.PREFER_ZEROPAGE || decl.zeropage==ZeropageWish.REQUIRE_ZEROPAGE)
-                        err("struct can not be in zeropage")
-                }
-                if(decl.struct!=null) {
-                    if(decl.zeropage==ZeropageWish.PREFER_ZEROPAGE || decl.zeropage==ZeropageWish.REQUIRE_ZEROPAGE)
-                        err("struct can not be in zeropage")
-                }
-
                 when(decl.value) {
                     null -> {
                         // a vardecl without an initial value, don't bother with it
@@ -547,30 +551,8 @@ internal class AstChecker(private val program: Program,
                         checkValueTypeAndRangeString(decl.datatype, decl.value as StringLiteralValue)
                     }
                     is ArrayLiteralValue -> {
-                        if(decl.datatype==DataType.STRUCT) {
-                            val struct = decl.struct!!
-                            val structLv = decl.value as ArrayLiteralValue
-                            if(struct.numberOfElements != structLv.value.size) {
-                                errors.err("struct value has incorrect number of elements", structLv.position)
-                                return
-                            }
-                            for(value in structLv.value.zip(struct.statements)) {
-                                val memberdecl = value.second as VarDecl
-                                val constValue = value.first.constValue(program)
-                                if(constValue==null) {
-                                    errors.err("struct literal value for field '${memberdecl.name}' should consist of compile-time constants", value.first.position)
-                                    return
-                                }
-                                val memberDt = memberdecl.datatype
-                                if(!checkValueTypeAndRange(memberDt, constValue)) {
-                                    errors.err("struct member value's type is not compatible with member field '${memberdecl.name}'", value.first.position)
-                                    return
-                                }
-                            }
-                        } else {
-                            val arraySpec = decl.arraysize ?: ArrayIndex.forArray(decl.value as ArrayLiteralValue)
-                            checkValueTypeAndRangeArray(decl.datatype, decl.struct, arraySpec, decl.value as ArrayLiteralValue)
-                        }
+                        val arraySpec = decl.arraysize ?: ArrayIndex.forArray(decl.value as ArrayLiteralValue)
+                        checkValueTypeAndRangeArray(decl.datatype, arraySpec, decl.value as ArrayLiteralValue)
                     }
                     is NumericLiteralValue -> {
                         checkValueTypeAndRange(decl.datatype, decl.value as NumericLiteralValue)
@@ -585,8 +567,9 @@ internal class AstChecker(private val program: Program,
                 }
             }
             VarDeclType.MEMORY -> {
-                if(decl.arraysize!=null) {
-                    val arraySize = decl.arraysize!!.constIndex() ?: 1
+                val arraysize = decl.arraysize
+                if(arraysize!=null) {
+                    val arraySize = arraysize.constIndex() ?: 1
                     when(decl.datatype) {
                         DataType.ARRAY_B, DataType.ARRAY_UB ->
                             if(arraySize > 256)
@@ -600,10 +583,9 @@ internal class AstChecker(private val program: Program,
                         else -> {}
                     }
                 }
-
-                if(decl.value is NumericLiteralValue) {
-                    val value = decl.value as NumericLiteralValue
-                    if (value.type !in IntegerDatatypes || value.number.toInt() < 0 || value.number.toInt() > 65535) {
+                val numvalue = decl.value as? NumericLiteralValue
+                if(numvalue!=null) {
+                    if (numvalue.type !in IntegerDatatypes || numvalue.number.toInt() < 0 || numvalue.number.toInt() > 65535) {
                         err("memory address must be valid integer 0..\$ffff", decl.value?.position)
                     }
                 } else {
@@ -614,23 +596,16 @@ internal class AstChecker(private val program: Program,
 
         val declValue = decl.value
         if(declValue!=null && decl.type==VarDeclType.VAR) {
-            if(decl.datatype==DataType.STRUCT) {
-                val valueIdt = declValue.inferType(program)
-                if(!valueIdt.isKnown)
-                    throw AstException("unknown dt")
-                val valueDt = valueIdt.typeOrElse(DataType.STRUCT)
-                if(valueDt !in ArrayDatatypes)
-                    err("initialisation of struct should be with array value", declValue.position)
-            } else if (!declValue.inferType(program).istype(decl.datatype)) {
+            if (!declValue.inferType(program).istype(decl.datatype)) {
                 err("initialisation value has incompatible type (${declValue.inferType(program)}) for the variable (${decl.datatype})", declValue.position)
             }
         }
 
         // array length limits and constant lenghts
         if(decl.isArray) {
-            val length = decl.arraysize!!.constIndex()
+            val length = decl.arraysize?.constIndex()
             if(length==null)
-                err("array length must be a constant")
+                err("array length must be known at compile-time")
             else {
                 when (decl.datatype) {
                     DataType.STR, DataType.ARRAY_UB, DataType.ARRAY_B -> {
@@ -712,20 +687,20 @@ internal class AstChecker(private val program: Program,
             }
             "%breakpoint" -> {
                 if(directive.parent !is INameScope || directive.parent is Module)
-                    err("this directive may only occur in a block")
+                    err("this directive can't be used here")
                 if(directive.args.isNotEmpty())
                     err("invalid breakpoint directive, expected no arguments")
             }
             "%asminclude" -> {
                 if(directive.parent !is INameScope || directive.parent is Module)
-                    err("this directive may only occur in a block")
-                if(directive.args.size!=2 || directive.args[0].str==null || directive.args[1].str==null)
-                    err("invalid asminclude directive, expected arguments: \"filename\", \"scopelabel\"")
+                    err("this directive can't be used here")
+                if(directive.args.size!=1 || directive.args[0].str==null)
+                    err("invalid asminclude directive, expected argument: \"filename\"")
                 checkFileExists(directive, directive.args[0].str!!)
             }
             "%asmbinary" -> {
                 if(directive.parent !is INameScope || directive.parent is Module)
-                    err("this directive may only occur in a block")
+                    err("this directive can't be used here")
                 val errormsg = "invalid asmbinary directive, expected arguments: \"filename\" [, offset [, length ] ]"
                 if(directive.args.isEmpty()) err(errormsg)
                 else if(directive.args.isNotEmpty() && directive.args[0].str==null) err(errormsg)
@@ -742,34 +717,38 @@ internal class AstChecker(private val program: Program,
                 else if(directive.args.map{it.name in setOf("enable_floats", "force_output", "no_sysinit", "align_word", "align_page")}.any { !it })
                     err("invalid option directive argument(s)")
             }
-            "%target" -> {
-                if(directive.parent !is Block && directive.parent !is Module)
-                    err("this directive may only occur in a block or at module level")
-                if(directive.args.size != 1)
-                    err("directive requires one argument")
-                if(directive.args.single().name !in setOf(C64Target.name, Cx16Target.name))
-                    err("invalid compilation target")
-            }
             else -> throw SyntaxError("invalid directive ${directive.directive}", directive.position)
         }
         super.visit(directive)
     }
 
     private fun checkFileExists(directive: Directive, filename: String) {
-        var definingModule = directive.parent
+        if (File(filename).isFile)
+            return
+
+        var definingModule = directive.parent   // TODO: why not just use directive.definingModule() here?
         while (definingModule !is Module)
             definingModule = definingModule.parent
-        if (!(filename.startsWith("library:") || definingModule.source.resolveSibling(filename).toFile().isFile || File(filename).isFile))
-            errors.err("included file not found: $filename", directive.position)
+        if (definingModule.isLibrary)
+            return
+
+        val s = definingModule.source?.pathString()
+        if (s != null) {
+            val sourceFileCandidate = Path(s).resolveSibling(filename).toFile()
+            if (sourceFileCandidate.isFile)
+                return
+        }
+
+        errors.err("included file not found: $filename", directive.position)
     }
 
     override fun visit(array: ArrayLiteralValue) {
         if(array.type.isKnown) {
-            if (!compilerOptions.floats && array.type.typeOrElse(DataType.STRUCT) in setOf(DataType.FLOAT, DataType.ARRAY_F)) {
+            if (!compilerOptions.floats && array.type.getOr(DataType.UNDEFINED) in setOf(DataType.FLOAT, DataType.ARRAY_F)) {
                 errors.err("floating point used, but that is not enabled via options", array.position)
             }
             val arrayspec = ArrayIndex.forArray(array)
-            checkValueTypeAndRangeArray(array.type.typeOrElse(DataType.STRUCT), null, arrayspec, array)
+            checkValueTypeAndRangeArray(array.type.getOr(DataType.UNDEFINED), arrayspec, array)
         }
 
         fun isPassByReferenceElement(e: Expression): Boolean {
@@ -791,8 +770,25 @@ internal class AstChecker(private val program: Program,
         super.visit(array)
     }
 
+    override fun visit(char: CharLiteral) {
+        try {  // just *try* if it can be encoded, don't actually do it
+            compTarget.encodeString(char.value.toString(), char.altEncoding)
+        } catch (cx: CharConversionException) {
+            errors.err(cx.message ?: "can't encode character", char.position)
+        }
+
+        super.visit(char)
+    }
+
     override fun visit(string: StringLiteralValue) {
         checkValueTypeAndRangeString(DataType.STR, string)
+
+        try {  // just *try* if it can be encoded, don't actually do it
+            compTarget.encodeString(string.value, string.altEncoding)
+        } catch (cx: CharConversionException) {
+            errors.err(cx.message ?: "can't encode string", string.position)
+        }
+
         super.visit(string)
     }
 
@@ -801,7 +797,7 @@ internal class AstChecker(private val program: Program,
         if(!idt.isKnown)
             return  // any error should be reported elsewhere
 
-        val dt = idt.typeOrElse(DataType.STRUCT)
+        val dt = idt.getOr(DataType.UNDEFINED)
         if(expr.operator=="-") {
             if (dt != DataType.BYTE && dt != DataType.WORD && dt != DataType.FLOAT) {
                 errors.err("can only take negative of a signed number type", expr.position)
@@ -826,8 +822,8 @@ internal class AstChecker(private val program: Program,
         if(!leftIDt.isKnown || !rightIDt.isKnown)
             return     // hopefully this error will be detected elsewhere
 
-        val leftDt = leftIDt.typeOrElse(DataType.STRUCT)
-        val rightDt = rightIDt.typeOrElse(DataType.STRUCT)
+        val leftDt = leftIDt.getOr(DataType.UNDEFINED)
+        val rightDt = rightIDt.getOr(DataType.UNDEFINED)
 
         when(expr.operator){
             "/", "%" -> {
@@ -1019,7 +1015,7 @@ internal class AstChecker(private val program: Program,
 
         if(target is BuiltinFunctionStatementPlaceholder) {
             if(target.name=="swap") {
-                // swap() is a bit weird because this one is translated into a operations directly, instead of being a function call
+                // swap() is a bit weird because this one is translated into an operations directly, instead of being a function call
                 val dt1 = args[0].inferType(program)
                 val dt2 = args[1].inferType(program)
                 if (dt1 != dt2)
@@ -1028,14 +1024,14 @@ internal class AstChecker(private val program: Program,
                     errors.err("swap requires 2 variables, not constant value(s)", position)
                 else if(args[0] isSameAs args[1])
                     errors.err("swap should have 2 different args", position)
-                else if(dt1.typeOrElse(DataType.STRUCT) !in NumericDatatypes)
+                else if(!dt1.isNumeric)
                     errors.err("swap requires args of numerical type", position)
             }
             else if(target.name=="all" || target.name=="any") {
                 if((args[0] as? AddressOf)?.identifier?.targetVarDecl(program)?.datatype == DataType.STR) {
                     errors.err("any/all on a string is useless (is always true unless the string is empty)", position)
                 }
-                if(args[0].inferType(program).typeOrElse(DataType.STR) == DataType.STR) {
+                if(args[0].inferType(program).getOr(DataType.STR) == DataType.STR) {
                     errors.err("any/all on a string is useless (is always true unless the string is empty)", position)
                 }
             }
@@ -1059,7 +1055,7 @@ internal class AstChecker(private val program: Program,
                             ident = fcall.args[0] as? IdentifierReference
                     }
                     if(ident!=null && ident.nameInSource[0] == "cx16" && ident.nameInSource[1].startsWith("r")) {
-                        val reg = RegisterOrPair.valueOf(ident.nameInSource[1].toUpperCase())
+                        val reg = RegisterOrPair.valueOf(ident.nameInSource[1].uppercase())
                         val same = params.filter { it.value.registerOrPair==reg }
                         for(s in same) {
                             if(s.index!=arg.index) {
@@ -1133,8 +1129,7 @@ internal class AstChecker(private val program: Program,
     }
 
     override fun visit(whenStatement: WhenStatement) {
-        val conditionType = whenStatement.condition.inferType(program).typeOrElse(DataType.STRUCT)
-        if(conditionType !in IntegerDatatypes)
+        if(!whenStatement.condition.inferType(program).isInteger)
             errors.err("when condition must be an integer value", whenStatement.position)
         val tally = mutableSetOf<Int>()
         for((choices, choiceNode) in whenStatement.choiceValues(program)) {
@@ -1165,7 +1160,7 @@ internal class AstChecker(private val program: Program,
                 when {
                     constvalue == null -> errors.err("choice value must be a constant", whenChoice.position)
                     constvalue.type !in IntegerDatatypes -> errors.err("choice value must be a byte or word", whenChoice.position)
-                    constvalue.type != conditionType.typeOrElse(DataType.STRUCT) -> errors.err("choice value datatype differs from condition value", whenChoice.position)
+                    constvalue.type != conditionType.getOr(DataType.UNDEFINED) -> errors.err("choice value datatype differs from condition value", whenChoice.position)
                 }
             }
         } else {
@@ -1175,32 +1170,12 @@ internal class AstChecker(private val program: Program,
         super.visit(whenChoice)
     }
 
-    override fun visit(structDecl: StructDecl) {
-        // a struct can only contain 1 or more vardecls and can not be nested
-        if(structDecl.statements.isEmpty())
-            errors.err("struct must contain at least one member", structDecl.position)
-
-        for(member in structDecl.statements){
-            val decl = member as? VarDecl
-            if(decl==null)
-                errors.err("struct can only contain variable declarations", structDecl.position)
-            else {
-                if(decl.zeropage==ZeropageWish.REQUIRE_ZEROPAGE || decl.zeropage==ZeropageWish.PREFER_ZEROPAGE)
-                    errors.err("struct can not contain zeropage members", decl.position)
-                if(decl.datatype !in NumericDatatypes)
-                    errors.err("structs can only contain numerical types", decl.position)
-            }
-        }
-    }
-
     private fun checkFunctionOrLabelExists(target: IdentifierReference, statement: Statement): Statement? {
-        val targetStatement = target.targetStatement(program)
-        if(targetStatement is Label || targetStatement is Subroutine || targetStatement is BuiltinFunctionStatementPlaceholder)
-            return targetStatement
-        else if(targetStatement==null)
-            errors.err("undefined function or subroutine: ${target.nameInSource.joinToString(".")}", statement.position)
-        else
-            errors.err("cannot call that: ${target.nameInSource.joinToString(".")}", statement.position)
+        when (val targetStatement = target.targetStatement(program)) {
+            is Label, is Subroutine, is BuiltinFunctionStatementPlaceholder -> return targetStatement
+            null -> errors.err("undefined function or subroutine: ${target.nameInSource.joinToString(".")}", statement.position)
+            else -> errors.err("cannot call that: ${target.nameInSource.joinToString(".")}", statement.position)
+        }
         return null
     }
 
@@ -1216,8 +1191,7 @@ internal class AstChecker(private val program: Program,
         else false
     }
 
-    private fun checkValueTypeAndRangeArray(targetDt: DataType, struct: StructDecl?,
-                                            arrayspec: ArrayIndex, value: ArrayLiteralValue) : Boolean {
+    private fun checkValueTypeAndRangeArray(targetDt: DataType, arrayspec: ArrayIndex, value: ArrayLiteralValue) : Boolean {
         fun err(msg: String) : Boolean {
             errors.err(msg, value.position)
             return false
@@ -1290,22 +1264,6 @@ internal class AstChecker(private val program: Program,
                 }
                 return err("invalid float array initialization value ${value.type}, expected $targetDt")
             }
-            DataType.STRUCT -> {
-                if(value.type.typeOrElse(DataType.STRUCT) in ArrayDatatypes) {
-                    if(value.value.size != struct!!.numberOfElements)
-                        return err("number of values is not the same as the number of members in the struct")
-                    for(elt in value.value.zip(struct.statements)) {
-                        val vardecl = elt.second as VarDecl
-                        val valuetype = elt.first.inferType(program)
-                        if (!valuetype.isKnown || valuetype isNotAssignableTo vardecl.datatype) {
-                            errors.err("invalid struct member init value type $valuetype, expected ${vardecl.datatype}", elt.first.position)
-                            return false
-                        }
-                    }
-                    return true
-                }
-                return false
-            }
             else -> return false
         }
     }
@@ -1408,15 +1366,6 @@ internal class AstChecker(private val program: Program,
             DataType.UWORD -> sourceDatatype== DataType.UBYTE || sourceDatatype== DataType.UWORD
             DataType.FLOAT -> sourceDatatype in NumericDatatypes
             DataType.STR -> sourceDatatype== DataType.STR
-            DataType.STRUCT -> {
-                if(sourceDatatype==DataType.STRUCT) {
-                    val structLv = sourceValue as ArrayLiteralValue
-                    val numValues = structLv.value.size
-                    val targetstruct = target.identifier!!.targetVarDecl(program)!!.struct!!
-                    return targetstruct.numberOfElements == numValues
-                }
-                false
-            }
             else -> {
                 errors.err("cannot assign new value to variable of type $targetDatatype", position)
                 false
@@ -1430,10 +1379,15 @@ internal class AstChecker(private val program: Program,
             errors.err("cannot assign word to byte, use msb() or lsb()?", position)
         }
         else if(sourceDatatype== DataType.FLOAT && targetDatatype in IntegerDatatypes)
-            errors.err("cannot assign float to ${targetDatatype.name.toLowerCase()}; possible loss of precision. Suggestion: round the value or revert to integer arithmetic", position)
+            errors.err("cannot assign float to ${targetDatatype.name.lowercase()}; possible loss of precision. Suggestion: round the value or revert to integer arithmetic", position)
         else {
             if(targetDatatype!=DataType.UWORD && sourceDatatype !in PassByReferenceDatatypes)
-                errors.err("cannot assign ${sourceDatatype.name.toLowerCase()} to ${targetDatatype.name.toLowerCase()}", position)
+                errors.err(
+                    "cannot assign ${sourceDatatype.name.lowercase()} to ${
+                        targetDatatype.name.lowercase(
+                            Locale.getDefault()
+                        )
+                    }", position)
         }
 
 

compiler/src/prog8/compiler/astprocessing/AstExtensions.kt

@@ -1,12 +1,68 @@
 package prog8.compiler.astprocessing
 
+import prog8.ast.Node
 import prog8.ast.Program
+import prog8.ast.base.DataType
 import prog8.ast.base.FatalAstException
+import prog8.ast.expressions.CharLiteral
+import prog8.ast.expressions.NumericLiteralValue
+import prog8.ast.expressions.RangeExpr
+import prog8.ast.expressions.StringLiteralValue
 import prog8.ast.statements.Directive
+import prog8.ast.walk.AstWalker
+import prog8.ast.walk.IAstModification
 import prog8.compiler.BeforeAsmGenerationAstChanger
 import prog8.compiler.CompilationOptions
 import prog8.compiler.IErrorReporter
+import prog8.compiler.IStringEncoding
 import prog8.compiler.target.ICompilationTarget
+import kotlin.math.abs
+
+
+fun RangeExpr.size(encoding: IStringEncoding): Int? {
+    val fromLv = (from as? NumericLiteralValue)
+    val toLv = (to as? NumericLiteralValue)
+    if(fromLv==null || toLv==null)
+        return null
+    return toConstantIntegerRange(encoding)?.count()
+}
+
+fun RangeExpr.toConstantIntegerRange(encoding: IStringEncoding): IntProgression? {
+    val fromVal: Int
+    val toVal: Int
+    val fromString = from as? StringLiteralValue
+    val toString = to as? StringLiteralValue
+    if(fromString!=null && toString!=null ) {
+        // string range -> int range over character values
+        fromVal = encoding.encodeString(fromString.value, fromString.altEncoding)[0].toInt()
+        toVal = encoding.encodeString(toString.value, fromString.altEncoding)[0].toInt()
+    } else {
+        val fromLv = from as? NumericLiteralValue
+        val toLv = to as? NumericLiteralValue
+        if(fromLv==null || toLv==null)
+            return null         // non-constant range
+        // integer range
+        fromVal = fromLv.number.toInt()
+        toVal = toLv.number.toInt()
+    }
+    val stepVal = (step as? NumericLiteralValue)?.number?.toInt() ?: 1
+    return makeRange(fromVal, toVal, stepVal)
+}
+
+private fun makeRange(fromVal: Int, toVal: Int, stepVal: Int): IntProgression {
+    return when {
+        fromVal <= toVal -> when {
+            stepVal <= 0 -> IntRange.EMPTY
+            stepVal == 1 -> fromVal..toVal
+            else -> fromVal..toVal step stepVal
+        }
+        else -> when {
+            stepVal >= 0 -> IntRange.EMPTY
+            stepVal == -1 -> fromVal downTo toVal
+            else -> fromVal downTo toVal step abs(stepVal)
+        }
+    }
+}
 
 
 internal fun Program.checkValid(compilerOptions: CompilationOptions, errors: IErrorReporter, compTarget: ICompilationTarget) {
@@ -17,13 +73,34 @@ internal fun Program.checkValid(compilerOptions: CompilationOptions, errors: IEr
 internal fun Program.processAstBeforeAsmGeneration(errors: IErrorReporter, compTarget: ICompilationTarget) {
     val fixer = BeforeAsmGenerationAstChanger(this, errors, compTarget)
     fixer.visit(this)
-    fixer.applyModifications()
+    while(errors.noErrors() && fixer.applyModifications()>0) {
+        fixer.visit(this)
+    }
 }
 
 internal fun Program.reorderStatements(errors: IErrorReporter) {
     val reorder = StatementReorderer(this, errors)
     reorder.visit(this)
-    reorder.applyModifications()
+    if(errors.noErrors()) {
+        reorder.applyModifications()
+        reorder.visit(this)
+        if(errors.noErrors())
+            reorder.applyModifications()
+    }
+}
+
+internal fun Program.charLiteralsToUByteLiterals(errors: IErrorReporter, enc: IStringEncoding) {
+    val walker = object : AstWalker() {
+        override fun after(char: CharLiteral, parent: Node): Iterable<IAstModification> {
+            return listOf(IAstModification.ReplaceNode(
+                char,
+                NumericLiteralValue(DataType.UBYTE, enc.encodeString(char.value.toString(), char.altEncoding)[0].toInt(), char.position),
+                parent
+            ))
+        }
+    }
+    walker.visit(this)
+    walker.applyModifications()
 }
 
 internal fun Program.addTypecasts(errors: IErrorReporter) {
@@ -37,12 +114,12 @@ internal fun Program.verifyFunctionArgTypes() {
     fixer.visit(this)
 }
 
-internal fun Program.checkIdentifiers(errors: IErrorReporter, compTarget: ICompilationTarget) {
+internal fun Program.checkIdentifiers(errors: IErrorReporter, options: CompilationOptions) {
 
-    val checker2 = AstIdentifiersChecker(this, errors, compTarget)
+    val checker2 = AstIdentifiersChecker(this, errors, options.compTarget)
     checker2.visit(this)
 
-    if(errors.isEmpty()) {
+    if(errors.noErrors()) {
         val transforms = AstVariousTransforms(this)
         transforms.visit(this)
         transforms.applyModifications()
@@ -51,47 +128,61 @@ internal fun Program.checkIdentifiers(errors: IErrorReporter, compTarget: ICompi
         lit2decl.applyModifications()
     }
 
-    if (modules.map { it.name }.toSet().size != modules.size) {
-        throw FatalAstException("modules should all be unique")
+    // Check if each module has a unique name.
+    // If not report those that haven't.
+    // TODO: move check for unique module names to earlier stage and/or to unit tests
+    val namesToModules = mapOf<String, MutableList<prog8.ast.Module>>().toMutableMap()
+    for (m in modules) {
+        val others = namesToModules[m.name]
+        if (others == null) {
+            namesToModules[m.name] = listOf(m).toMutableList()
+        } else {
+            others.add(m)
+        }
+    }
+    val nonUniqueNames = namesToModules.keys
+        .map { Pair(it, namesToModules[it]!!.size) }
+        .filter { it.second > 1 }
+        .map { "\"${it.first}\" (x${it.second})"}
+    if (nonUniqueNames.isNotEmpty()) {
+        throw FatalAstException("modules must have unique names; of the ttl ${modules.size} these have not: $nonUniqueNames")
     }
 }
 
-internal fun Program.variousCleanups() {
-    val process = VariousCleanups()
+internal fun Program.variousCleanups(program: Program, errors: IErrorReporter) {
+    val process = VariousCleanups(program, errors)
     process.visit(this)
-    process.applyModifications()
+    if(errors.noErrors())
+        process.applyModifications()
 }
 
+
 internal fun Program.moveMainAndStartToFirst() {
     // the module containing the program entrypoint is moved to the first in the sequence.
     // the "main" block containing the entrypoint is moved to the top in there,
     // and finally the entrypoint subroutine "start" itself is moved to the top in that block.
 
     val directives = modules[0].statements.filterIsInstance<Directive>()
-    val start = this.entrypoint()
-    if(start!=null) {
-        val mod = start.definingModule()
-        val block = start.definingBlock()
-        if(!modules.remove(mod))
-            throw FatalAstException("module wrong")
-        modules.add(0, mod)
-        mod.remove(block)
-        var afterDirective = mod.statements.indexOfFirst { it !is Directive }
-        if(afterDirective<0)
-            mod.statements.add(block)
-        else
-            mod.statements.add(afterDirective, block)
-        block.remove(start)
-        afterDirective = block.statements.indexOfFirst { it !is Directive }
-        if(afterDirective<0)
-            block.statements.add(start)
-        else
-            block.statements.add(afterDirective, start)
+    val start = this.entrypoint
+    val mod = start.definingModule
+    val block = start.definingBlock
+    moveModuleToFront(mod)
+    mod.remove(block)
+    var afterDirective = mod.statements.indexOfFirst { it !is Directive }
+    if(afterDirective<0)
+        mod.statements.add(block)
+    else
+        mod.statements.add(afterDirective, block)
+    block.remove(start)
+    afterDirective = block.statements.indexOfFirst { it !is Directive }
+    if(afterDirective<0)
+        block.statements.add(start)
+    else
+        block.statements.add(afterDirective, start)
 
-        // overwrite the directives in the module containing the entrypoint
-        for(directive in directives) {
-            modules[0].statements.removeAll { it is Directive && it.directive == directive.directive }
-            modules[0].statements.add(0, directive)
-        }
+    // overwrite the directives in the module containing the entrypoint
+    for(directive in directives) {
+        modules[0].statements.removeAll { it is Directive && it.directive == directive.directive }
+        modules[0].statements.add(0, directive)
     }
 }

compiler/src/prog8/compiler/astprocessing/AstIdentifiersChecker.kt

@@ -1,12 +1,7 @@
 package prog8.compiler.astprocessing
 
-import prog8.ast.Module
 import prog8.ast.Program
-import prog8.ast.base.DataType
-import prog8.ast.base.NumericDatatypes
 import prog8.ast.base.Position
-import prog8.ast.expressions.ArrayLiteralValue
-import prog8.ast.expressions.NumericLiteralValue
 import prog8.ast.expressions.StringLiteralValue
 import prog8.ast.statements.*
 import prog8.ast.walk.IAstVisitor
@@ -21,42 +16,23 @@ internal class AstIdentifiersChecker(private val program: Program, private val e
         errors.err("name conflict '$name', also defined in ${existing.position.file} line ${existing.position.line}", position)
     }
 
-    override fun visit(module: Module) {
-        blocks.clear()  // blocks may be redefined within a different module
-
-        super.visit(module)
-    }
-
     override fun visit(block: Block) {
         if(block.name in compTarget.machine.opcodeNames)
             errors.err("can't use a cpu opcode name as a symbol: '${block.name}'", block.position)
 
         val existing = blocks[block.name]
-        if(existing!=null)
-            nameError(block.name, block.position, existing)
+        if(existing!=null) {
+            if(block.isInLibrary)
+                nameError(existing.name, existing.position, block)
+            else
+                nameError(block.name, block.position, existing)
+        }
         else
             blocks[block.name] = block
 
-        if(!block.isInLibrary) {
-            val libraries = program.modules.filter { it.isLibraryModule }
-            val libraryBlockNames = libraries.flatMap { it.statements.filterIsInstance<Block>().map { b -> b.name } }
-            if(block.name in libraryBlockNames)
-                errors.err("block is already defined in an included library module", block.position)
-        }
-
         super.visit(block)
     }
 
-    override fun visit(directive: Directive) {
-        if(directive.directive=="%target") {
-            val compatibleTarget = directive.args.single().name
-            if (compatibleTarget != compTarget.name)
-                errors.err("module's compilation target ($compatibleTarget) differs from active target (${compTarget.name})", directive.position)
-        }
-
-        super.visit(directive)
-    }
-
     override fun visit(decl: VarDecl) {
         decl.datatypeErrors.forEach { errors.err(it.message, it.position) }
 
@@ -66,37 +42,14 @@ internal class AstIdentifiersChecker(private val program: Program, private val e
         if(decl.name in compTarget.machine.opcodeNames)
             errors.err("can't use a cpu opcode name as a symbol: '${decl.name}'", decl.position)
 
-        if(decl.datatype==DataType.STRUCT) {
-            if (decl.structHasBeenFlattened)
-                return super.visit(decl)    // don't do this multiple times
-
-            if (decl.struct == null) {
-                errors.err("undefined struct type", decl.position)
-                return super.visit(decl)
-            }
-
-            if (decl.struct!!.statements.any { (it as VarDecl).datatype !in NumericDatatypes })
-                return super.visit(decl)     // a non-numeric member, not supported. proper error is given by AstChecker later
-
-            if (decl.value is NumericLiteralValue) {
-                errors.err("you cannot initialize a struct using a single value", decl.position)
-                return super.visit(decl)
-            }
-
-            if (decl.value != null && decl.value !is ArrayLiteralValue) {
-                errors.err("initializing a struct requires array literal value", decl.value?.position ?: decl.position)
-                return super.visit(decl)
-            }
-        }
-
         val existing = program.namespace.lookup(listOf(decl.name), decl)
         if (existing != null && existing !== decl)
             nameError(decl.name, decl.position, existing)
 
-        if(decl.definingBlock().name==decl.name)
-            nameError(decl.name, decl.position, decl.definingBlock())
-        if(decl.definingSubroutine()?.name==decl.name)
-            nameError(decl.name, decl.position, decl.definingSubroutine()!!)
+        if(decl.definingBlock.name==decl.name)
+            nameError(decl.name, decl.position, decl.definingBlock)
+        if(decl.definingSubroutine?.name==decl.name)
+            nameError(decl.name, decl.position, decl.definingSubroutine!!)
 
         super.visit(decl)
     }
@@ -116,8 +69,8 @@ internal class AstIdentifiersChecker(private val program: Program, private val e
             if (existing != null && existing !== subroutine)
                 nameError(subroutine.name, subroutine.position, existing)
 
-            // check that there are no local variables, labels, or other subs that redefine the subroutine's parameters
-            val symbolsInSub = subroutine.allDefinedSymbols()
+            // check that there are no local variables, labels, or other subs that redefine the subroutine's parameters. Blocks are okay.
+            val symbolsInSub = subroutine.allDefinedSymbols
             val namesInSub = symbolsInSub.map{ it.first }.toSet()
             val paramNames = subroutine.parameters.map { it.name }.toSet()
             val paramsToCheck = paramNames.intersect(namesInSub)
@@ -128,14 +81,17 @@ internal class AstIdentifiersChecker(private val program: Program, private val e
                 val sub = subroutine.statements.firstOrNull { it is Subroutine && it.name==name}
                 if(sub!=null)
                     nameError(name, subroutine.position, sub)
-                val block = program.allBlocks().firstOrNull { it.name==name }
-                if(block!=null)
-                    nameError(name, subroutine.position, block)
             }
 
             if(subroutine.isAsmSubroutine && subroutine.statements.any{it !is InlineAssembly}) {
                 errors.err("asmsub can only contain inline assembly (%asm)", subroutine.position)
             }
+
+            if(subroutine.name == subroutine.definingBlock.name) {
+                // subroutines cannot have the same name as their enclosing block,
+                // because this causes symbol scoping issues in the resulting assembly source
+                nameError(subroutine.name, subroutine.position, subroutine.definingBlock)
+            }
         }
 
         super.visit(subroutine)
@@ -149,7 +105,7 @@ internal class AstIdentifiersChecker(private val program: Program, private val e
             // the builtin functions can't be redefined
             errors.err("builtin function cannot be redefined", label.position)
         } else {
-            val existing = label.definingSubroutine()?.getAllLabels(label.name) ?: emptyList()
+            val existing = label.definingSubroutine?.getAllLabels(label.name) ?: emptyList()
             for(el in existing) {
                 if(el === label || el.name != label.name)
                     continue
@@ -169,14 +125,4 @@ internal class AstIdentifiersChecker(private val program: Program, private val e
 
         super.visit(string)
     }
-
-    override fun visit(structDecl: StructDecl) {
-        for(member in structDecl.statements){
-            val decl = member as? VarDecl
-            if(decl!=null && decl.datatype !in NumericDatatypes)
-                errors.err("structs can only contain numerical types", decl.position)
-        }
-
-        super.visit(structDecl)
-    }
 }

compiler/src/prog8/compiler/astprocessing/AstVariousTransforms.kt

@@ -3,38 +3,21 @@ package prog8.compiler.astprocessing
 import prog8.ast.Node
 import prog8.ast.Program
 import prog8.ast.base.DataType
+import prog8.ast.expressions.ArrayIndexedExpression
 import prog8.ast.expressions.BinaryExpression
+import prog8.ast.expressions.DirectMemoryRead
 import prog8.ast.expressions.StringLiteralValue
-import prog8.ast.statements.AnonymousScope
-import prog8.ast.statements.ParameterVarDecl
-import prog8.ast.statements.Subroutine
-import prog8.ast.statements.VarDecl
+import prog8.ast.statements.*
 import prog8.ast.walk.AstWalker
 import prog8.ast.walk.IAstModification
 
 
 internal class AstVariousTransforms(private val program: Program) : AstWalker() {
-    private val noModifications = emptyList<IAstModification>()
-
-    override fun before(decl: VarDecl, parent: Node): Iterable<IAstModification> {
-        // is it a struct variable? then define all its struct members as mangled names,
-        //    and include the original decl as well.
-        if(decl.datatype==DataType.STRUCT && !decl.structHasBeenFlattened) {
-            val decls = decl.flattenStructMembers()
-            decls.add(decl)
-            val result = AnonymousScope(decls, decl.position)
-            return listOf(IAstModification.ReplaceNode(
-                    decl, result, parent
-            ))
-        }
-
-        return noModifications
-    }
 
     override fun after(subroutine: Subroutine, parent: Node): Iterable<IAstModification> {
         // For non-kernal subroutines and non-asm parameters:
         // inject subroutine params as local variables (if they're not there yet).
-        val symbolsInSub = subroutine.allDefinedSymbols()
+        val symbolsInSub = subroutine.allDefinedSymbols
         val namesInSub = symbolsInSub.map{ it.first }.toSet()
         if(subroutine.asmAddress==null) {
             if(subroutine.asmParameterRegisters.isEmpty() && subroutine.parameters.isNotEmpty()) {
@@ -83,6 +66,10 @@ internal class AstVariousTransforms(private val program: Program) : AstWalker()
         return noModifications
     }
 
+    override fun after(arrayIndexedExpression: ArrayIndexedExpression, parent: Node): Iterable<IAstModification> {
+        return replacePointerVarIndexWithMemread(program, arrayIndexedExpression, parent)
+    }
+
     private fun concatString(expr: BinaryExpression): StringLiteralValue? {
         val rightStrval = expr.right as? StringLiteralValue
         val leftStrval = expr.left as? StringLiteralValue
@@ -109,3 +96,25 @@ internal class AstVariousTransforms(private val program: Program) : AstWalker()
         }
     }
 }
+
+
+
+internal fun replacePointerVarIndexWithMemread(program: Program, arrayIndexedExpression: ArrayIndexedExpression, parent: Node): Iterable<IAstModification> {
+    val arrayVar = arrayIndexedExpression.arrayvar.targetVarDecl(program)
+    if(arrayVar!=null && arrayVar.datatype ==  DataType.UWORD) {
+        // rewrite   pointervar[index]  into  @(pointervar+index)
+        val indexer = arrayIndexedExpression.indexer
+        val add = BinaryExpression(arrayIndexedExpression.arrayvar, "+", indexer.indexExpr, arrayIndexedExpression.position)
+        return if(parent is AssignTarget) {
+            // we're part of the target of an assignment, we have to actually change the assign target itself
+            val memwrite = DirectMemoryWrite(add, arrayIndexedExpression.position)
+            val newtarget = AssignTarget(null, null, memwrite, arrayIndexedExpression.position)
+            listOf(IAstModification.ReplaceNode(parent, newtarget, parent.parent))
+        } else {
+            val memread = DirectMemoryRead(add, arrayIndexedExpression.position)
+            listOf(IAstModification.ReplaceNode(arrayIndexedExpression, memread, parent))
+        }
+    }
+
+    return emptyList()
+}

compiler/src/prog8/compiler/astprocessing/LiteralsToAutoVars.kt

@@ -13,11 +13,10 @@ import prog8.ast.walk.IAstModification
 
 
 internal class LiteralsToAutoVars(private val program: Program) : AstWalker() {
-    private val noModifications = emptyList<IAstModification>()
 
     override fun after(string: StringLiteralValue, parent: Node): Iterable<IAstModification> {
         if(string.parent !is VarDecl && string.parent !is WhenChoice) {
-            // replace the literal string by a identifier reference to the interned string
+            // replace the literal string by an identifier reference to the interned string
             val scopedName = program.internString(string)
             val identifier = IdentifierReference(scopedName, string.position)
             return listOf(IAstModification.ReplaceNode(string, identifier, parent))
@@ -39,13 +38,13 @@ internal class LiteralsToAutoVars(private val program: Program) : AstWalker() {
             val arrayDt = array.guessDatatype(program)
             if(arrayDt.isKnown) {
                 // this array literal is part of an expression, turn it into an identifier reference
-                val litval2 = array.cast(arrayDt.typeOrElse(DataType.STRUCT))
+                val litval2 = array.cast(arrayDt.getOr(DataType.UNDEFINED))
                 if(litval2!=null) {
                     val vardecl2 = VarDecl.createAuto(litval2)
                     val identifier = IdentifierReference(listOf(vardecl2.name), vardecl2.position)
                     return listOf(
                             IAstModification.ReplaceNode(array, identifier, parent),
-                            IAstModification.InsertFirst(vardecl2, array.definingScope())
+                            IAstModification.InsertFirst(vardecl2, array.definingScope)
                     )
                 }
             }

compiler/src/prog8/compiler/astprocessing/StatementReorderer.kt

@@ -4,7 +4,8 @@ import prog8.ast.IFunctionCall
 import prog8.ast.Module
 import prog8.ast.Node
 import prog8.ast.Program
-import prog8.ast.base.*
+import prog8.ast.base.DataType
+import prog8.ast.base.FatalAstException
 import prog8.ast.expressions.*
 import prog8.ast.statements.*
 import prog8.ast.walk.AstWalker
@@ -21,12 +22,10 @@ internal class StatementReorderer(val program: Program, val errors: IErrorReport
     // - in every block and module, most directives and vardecls are moved to the top. (not in subroutines!)
     // - the 'start' subroutine is moved to the top.
     // - (syntax desugaring) a vardecl with a non-const initializer value is split into a regular vardecl and an assignment statement.
-    // - (syntax desugaring) struct value assignment is expanded into several struct member assignments.
     // - in-place assignments are reordered a bit so that they are mostly of the form A = A <operator> <rest>
     // - sorts the choices in when statement.
-    // - insert AddressOf (&) expression where required (string params to a UWORD function param etc).
+    // - insert AddressOf (&) expression where required (string params to a UWORD function param etc.).
 
-    private val noModifications = emptyList<IAstModification>()
     private val directivesToMove = setOf("%output", "%launcher", "%zeropage", "%zpreserved", "%address", "%option")
 
     override fun after(module: Module, parent: Node): Iterable<IAstModification> {
@@ -87,27 +86,17 @@ internal class StatementReorderer(val program: Program, val errors: IErrorReport
     }
 
     override fun after(arrayIndexedExpression: ArrayIndexedExpression, parent: Node): Iterable<IAstModification> {
-
-        val arrayVar = arrayIndexedExpression.arrayvar.targetVarDecl(program)
-        if(arrayVar!=null && arrayVar.datatype ==  DataType.UWORD) {
-            // rewrite   pointervar[index]  into  @(pointervar+index)
-            val indexer = arrayIndexedExpression.indexer
-            val add = BinaryExpression(arrayIndexedExpression.arrayvar, "+", indexer.indexExpr, arrayIndexedExpression.position)
-            return if(parent is AssignTarget) {
-                // we're part of the target of an assignment, we have to actually change the assign target itself
-                val memwrite = DirectMemoryWrite(add, arrayIndexedExpression.position)
-                val newtarget = AssignTarget(null, null, memwrite, arrayIndexedExpression.position)
-                listOf(IAstModification.ReplaceNode(parent, newtarget, parent.parent))
-            } else {
-                val memread = DirectMemoryRead(add, arrayIndexedExpression.position)
-                listOf(IAstModification.ReplaceNode(arrayIndexedExpression, memread, parent))
-            }
-        }
-
-        return noModifications
+        return replacePointerVarIndexWithMemread(program, arrayIndexedExpression, parent)
     }
 
     override fun after(expr: BinaryExpression, parent: Node): Iterable<IAstModification> {
+
+        // ConstValue <associativeoperator> X -->  X <associativeoperator> ConstValue
+        // (this should be done by the ExpressionSimplifier when optimizing is enabled,
+        //  but the current assembly code generator for IF statements now also depends on it, so we do it here regardless of optimization.)
+        if (expr.left.constValue(program) != null && expr.operator in associativeOperators && expr.right.constValue(program) == null)
+            return listOf(IAstModification.SwapOperands(expr))
+
         // when using a simple bit shift and assigning it to a variable of a different type,
         // try to make the bit shifting 'wide enough' to fall into the variable's type.
         // with this, for instance, uword x = 1 << 10  will result in 1024 rather than 0 (the ubyte result).
@@ -117,7 +106,7 @@ internal class StatementReorderer(val program: Program, val errors: IErrorReport
                 is Assignment -> {
                     val targetDt = parent.target.inferType(program)
                     if(leftDt != targetDt) {
-                        val cast = TypecastExpression(expr.left, targetDt.typeOrElse(DataType.STRUCT), true, parent.position)
+                        val cast = TypecastExpression(expr.left, targetDt.getOr(DataType.UNDEFINED), true, parent.position)
                         return listOf(IAstModification.ReplaceNode(expr.left, cast, expr))
                     }
                 }
@@ -197,43 +186,13 @@ internal class StatementReorderer(val program: Program, val errors: IErrorReport
         return noModifications
     }
 
-    override fun after(decl: VarDecl, parent: Node): Iterable<IAstModification> {
-        val declValue = decl.value
-        if(declValue!=null && decl.type== VarDeclType.VAR && decl.datatype in NumericDatatypes) {
-            val declConstValue = declValue.constValue(program)
-            if(declConstValue==null) {
-                // move the vardecl (without value) to the scope and replace this with a regular assignment
-                // Unless we're dealing with a floating point variable because that will actually make things less efficient at the moment (because floats are mostly calcualated via the stack)
-                if(decl.datatype!=DataType.FLOAT) {
-                    decl.value = null
-                    decl.allowInitializeWithZero = false
-                    val target = AssignTarget(IdentifierReference(listOf(decl.name), decl.position), null, null, decl.position)
-                    val assign = Assignment(target, declValue, decl.position)
-                    return listOf(
-                            IAstModification.ReplaceNode(decl, assign, parent),
-                            IAstModification.InsertFirst(decl, decl.definingScope())
-                    )
-                }
-            }
-        }
-        return noModifications
-    }
-
     override fun before(assignment: Assignment, parent: Node): Iterable<IAstModification> {
         val valueType = assignment.value.inferType(program)
         val targetType = assignment.target.inferType(program)
 
-        if(targetType.istype(DataType.STRUCT) && (valueType.istype(DataType.STRUCT) || valueType.typeOrElse(DataType.STRUCT) in ArrayDatatypes )) {
+        if(targetType.isArray && valueType.isArray) {
             if (assignment.value is ArrayLiteralValue) {
-                errors.err("cannot assign non-const array value, use separate assignment per field", assignment.position)
-            } else {
-                return copyStructValue(assignment)
-            }
-        }
-
-        if(targetType.typeOrElse(DataType.STRUCT) in ArrayDatatypes && valueType.typeOrElse(DataType.STRUCT) in ArrayDatatypes ) {
-            if (assignment.value is ArrayLiteralValue) {
-                errors.err("cannot assign non-const array value, use separate assignment per element", assignment.position)
+                errors.err("cannot assign array literal here, use separate assignment per element", assignment.position)
             } else {
                 return copyArrayValue(assignment)
             }
@@ -313,7 +272,7 @@ internal class StatementReorderer(val program: Program, val errors: IErrorReport
                 errors.err("element type mismatch", assign.position)
         }
 
-        if(!errors.isEmpty())
+        if(!errors.noErrors())
             return noModifications
 
         val memcopy = FunctionCallStatement(IdentifierReference(listOf("sys", "memcopy"), assign.position),
@@ -327,73 +286,4 @@ internal class StatementReorderer(val program: Program, val errors: IErrorReport
         )
         return listOf(IAstModification.ReplaceNode(assign, memcopy, assign.parent))
     }
-
-    private fun copyStructValue(structAssignment: Assignment): List<IAstModification> {
-        val identifier = structAssignment.target.identifier!!
-        val targetVar = identifier.targetVarDecl(program)!!
-        val struct = targetVar.struct!!
-        when (structAssignment.value) {
-            is IdentifierReference -> {
-                val sourceVar = (structAssignment.value as IdentifierReference).targetVarDecl(program)!!
-                val memsize = struct.memsize(program.memsizer)
-                when {
-                    sourceVar.struct!=null -> {
-                        // struct memberwise copy
-                        val sourceStruct = sourceVar.struct!!
-                        if(sourceStruct!==targetVar.struct) {
-                            errors.err("struct type mismatch", structAssignment.position)
-                            return listOf()
-                        }
-                        if(struct.statements.size!=sourceStruct.statements.size) {
-                            errors.err("struct element count mismatch", structAssignment.position)
-                            return listOf()
-                        }
-                        if(memsize!=sourceStruct.memsize(program.memsizer)) {
-                            errors.err("memory size mismatch", structAssignment.position)
-                            return listOf()
-                        }
-                        val memcopy = FunctionCallStatement(IdentifierReference(listOf("sys", "memcopy"), structAssignment.position),
-                            mutableListOf(
-                                AddressOf(structAssignment.value as IdentifierReference, structAssignment.position),
-                                AddressOf(identifier, structAssignment.position),
-                                NumericLiteralValue.optimalInteger(memsize, structAssignment.position)
-                            ),
-                            true,
-                            structAssignment.position
-                        )
-                        return listOf(IAstModification.ReplaceNode(structAssignment, memcopy, structAssignment.parent))
-                    }
-                    sourceVar.isArray -> {
-                        val array = sourceVar.value as ArrayLiteralValue
-                        if(struct.statements.size!=array.value.size) {
-                            errors.err("struct element count mismatch", structAssignment.position)
-                            return listOf()
-                        }
-                        if(memsize!=array.memsize(program.memsizer)) {
-                            errors.err("memory size mismatch", structAssignment.position)
-                            return listOf()
-                        }
-                        val memcopy = FunctionCallStatement(IdentifierReference(listOf("sys", "memcopy"), structAssignment.position),
-                            mutableListOf(
-                                AddressOf(structAssignment.value as IdentifierReference, structAssignment.position),
-                                AddressOf(identifier, structAssignment.position),
-                                NumericLiteralValue.optimalInteger(memsize, structAssignment.position)
-                            ),
-                            true,
-                            structAssignment.position
-                        )
-                        return listOf(IAstModification.ReplaceNode(structAssignment, memcopy, structAssignment.parent))
-                    }
-                    else -> {
-                        throw FatalAstException("can only assign arrays or structs to structs")
-                    }
-                }
-            }
-            is ArrayLiteralValue -> {
-                throw IllegalArgumentException("not going to do a structLv assignment here")
-            }
-            else -> throw FatalAstException("strange struct value")
-        }
-    }
-
 }

compiler/src/prog8/compiler/astprocessing/TypecastsAdder.kt

@@ -18,16 +18,18 @@ class TypecastsAdder(val program: Program, val errors: IErrorReporter) : AstWalk
      * (this includes function call arguments)
      */
 
-    private val noModifications = emptyList<IAstModification>()
-
     override fun after(decl: VarDecl, parent: Node): Iterable<IAstModification> {
         val declValue = decl.value
-        if(decl.type==VarDeclType.VAR && declValue!=null && decl.struct==null) {
+        if(decl.type==VarDeclType.VAR && declValue!=null) {
             val valueDt = declValue.inferType(program)
             if(!valueDt.istype(decl.datatype)) {
 
                 // don't add a typecast on an array initializer value
-                if(valueDt.typeOrElse(DataType.STRUCT) in IntegerDatatypes && decl.datatype in ArrayDatatypes)
+                if(valueDt.isInteger && decl.datatype in ArrayDatatypes)
+                    return noModifications
+
+                // don't add a typecast if the initializer value is inherently not assignable
+                if(valueDt isNotAssignableTo decl.datatype)
                     return noModifications
 
                 return listOf(IAstModification.ReplaceNode(
@@ -45,7 +47,7 @@ class TypecastsAdder(val program: Program, val errors: IErrorReporter) : AstWalk
         val rightDt = expr.right.inferType(program)
         if(leftDt.isKnown && rightDt.isKnown && leftDt!=rightDt) {
             // determine common datatype and add typecast as required to make left and right equal types
-            val (commonDt, toFix) = BinaryExpression.commonDatatype(leftDt.typeOrElse(DataType.STRUCT), rightDt.typeOrElse(DataType.STRUCT), expr.left, expr.right)
+            val (commonDt, toFix) = BinaryExpression.commonDatatype(leftDt.getOr(DataType.UNDEFINED), rightDt.getOr(DataType.UNDEFINED), expr.left, expr.right)
             if(toFix!=null) {
                 return when {
                     toFix===expr.left -> listOf(IAstModification.ReplaceNode(
@@ -64,8 +66,8 @@ class TypecastsAdder(val program: Program, val errors: IErrorReporter) : AstWalk
         val valueItype = assignment.value.inferType(program)
         val targetItype = assignment.target.inferType(program)
         if(targetItype.isKnown && valueItype.isKnown) {
-            val targettype = targetItype.typeOrElse(DataType.STRUCT)
-            val valuetype = valueItype.typeOrElse(DataType.STRUCT)
+            val targettype = targetItype.getOr(DataType.UNDEFINED)
+            val valuetype = valueItype.getOr(DataType.UNDEFINED)
             if (valuetype != targettype) {
                 if (valuetype isAssignableTo targettype) {
                     if(valuetype in IterableDatatypes && targettype==DataType.UWORD)
@@ -124,7 +126,7 @@ class TypecastsAdder(val program: Program, val errors: IErrorReporter) : AstWalk
                 sub.parameters.zip(call.args).forEachIndexed { index, pair ->
                     val argItype = pair.second.inferType(program)
                     if(argItype.isKnown) {
-                        val argtype = argItype.typeOrElse(DataType.STRUCT)
+                        val argtype = argItype.getOr(DataType.UNDEFINED)
                         val requiredType = pair.first.type
                         if (requiredType != argtype) {
                             if (argtype isAssignableTo requiredType) {
@@ -157,7 +159,7 @@ class TypecastsAdder(val program: Program, val errors: IErrorReporter) : AstWalk
                 func.parameters.zip(call.args).forEachIndexed { index, pair ->
                     val argItype = pair.second.inferType(program)
                     if (argItype.isKnown) {
-                        val argtype = argItype.typeOrElse(DataType.STRUCT)
+                        val argtype = argItype.getOr(DataType.UNDEFINED)
                         if (pair.first.possibleDatatypes.all { argtype != it }) {
                             for (possibleType in pair.first.possibleDatatypes) {
                                 if (argtype isAssignableTo possibleType) {
@@ -189,7 +191,7 @@ class TypecastsAdder(val program: Program, val errors: IErrorReporter) : AstWalk
     override fun after(memread: DirectMemoryRead, parent: Node): Iterable<IAstModification> {
         // make sure the memory address is an uword
         val dt = memread.addressExpression.inferType(program)
-        if(dt.isKnown && dt.typeOrElse(DataType.UWORD)!=DataType.UWORD) {
+        if(dt.isKnown && dt.getOr(DataType.UWORD)!=DataType.UWORD) {
             val typecast = (memread.addressExpression as? NumericLiteralValue)?.cast(DataType.UWORD)?.valueOrZero()
                     ?: TypecastExpression(memread.addressExpression, DataType.UWORD, true, memread.addressExpression.position)
             return listOf(IAstModification.ReplaceNode(memread.addressExpression, typecast, memread))
@@ -200,7 +202,7 @@ class TypecastsAdder(val program: Program, val errors: IErrorReporter) : AstWalk
     override fun after(memwrite: DirectMemoryWrite, parent: Node): Iterable<IAstModification> {
         // make sure the memory address is an uword
         val dt = memwrite.addressExpression.inferType(program)
-        if(dt.isKnown && dt.typeOrElse(DataType.UWORD)!=DataType.UWORD) {
+        if(dt.isKnown && dt.getOr(DataType.UWORD)!=DataType.UWORD) {
             val typecast = (memwrite.addressExpression as? NumericLiteralValue)?.cast(DataType.UWORD)?.valueOrZero()
                     ?: TypecastExpression(memwrite.addressExpression, DataType.UWORD, true, memwrite.addressExpression.position)
             return listOf(IAstModification.ReplaceNode(memwrite.addressExpression, typecast, memwrite))
@@ -212,7 +214,7 @@ class TypecastsAdder(val program: Program, val errors: IErrorReporter) : AstWalk
         // add a typecast to the return type if it doesn't match the subroutine's signature
         val returnValue = returnStmt.value
         if(returnValue!=null) {
-            val subroutine = returnStmt.definingSubroutine()!!
+            val subroutine = returnStmt.definingSubroutine!!
             if(subroutine.returntypes.size==1) {
                 val subReturnType = subroutine.returntypes.first()
                 if (returnValue.inferType(program).istype(subReturnType))

compiler/src/prog8/compiler/astprocessing/VariousCleanups.kt

@@ -3,18 +3,17 @@ package prog8.compiler.astprocessing
 import prog8.ast.IFunctionCall
 import prog8.ast.INameScope
 import prog8.ast.Node
+import prog8.ast.Program
+import prog8.ast.base.FatalAstException
 import prog8.ast.base.Position
-import prog8.ast.expressions.DirectMemoryRead
-import prog8.ast.expressions.FunctionCall
-import prog8.ast.expressions.NumericLiteralValue
-import prog8.ast.expressions.TypecastExpression
+import prog8.ast.expressions.*
 import prog8.ast.statements.*
 import prog8.ast.walk.AstWalker
 import prog8.ast.walk.IAstModification
+import prog8.compiler.IErrorReporter
 
 
-internal class VariousCleanups: AstWalker() {
-    private val noModifications = emptyList<IAstModification>()
+internal class VariousCleanups(val program: Program, val errors: IErrorReporter): AstWalker() {
 
     override fun before(nopStatement: NopStatement, parent: Node): Iterable<IAstModification> {
         return listOf(IAstModification.Remove(nopStatement, parent as INameScope))
@@ -32,21 +31,12 @@ internal class VariousCleanups: AstWalker() {
             val idx = into.statements.indexOf(scope)
             if(idx>=0) {
                 into.statements.addAll(idx+1, scope.statements)
+                scope.statements.forEach { it.parent = into as Node }
                 into.statements.remove(scope)
             }
         }
     }
 
-    override fun before(typecast: TypecastExpression, parent: Node): Iterable<IAstModification> {
-        if(typecast.expression is NumericLiteralValue) {
-            val value = (typecast.expression as NumericLiteralValue).cast(typecast.type)
-            if(value.isValid)
-                return listOf(IAstModification.ReplaceNode(typecast, value.valueOrZero(), parent))
-        }
-
-        return noModifications
-    }
-
     override fun before(functionCallStatement: FunctionCallStatement, parent: Node): Iterable<IAstModification> {
         return before(functionCallStatement as IFunctionCall, parent, functionCallStatement.position)
     }
@@ -70,4 +60,62 @@ internal class VariousCleanups: AstWalker() {
         return noModifications
     }
 
+    override fun after(typecast: TypecastExpression, parent: Node): Iterable<IAstModification> {
+        if(typecast.parent!==parent)
+            throw FatalAstException("parent node mismatch at $typecast")
+
+        if(typecast.expression is NumericLiteralValue) {
+            val value = (typecast.expression as NumericLiteralValue).cast(typecast.type)
+            if(value.isValid)
+                return listOf(IAstModification.ReplaceNode(typecast, value.valueOrZero(), parent))
+        }
+
+        val sourceDt = typecast.expression.inferType(program)
+        if(sourceDt.istype(typecast.type))
+            return listOf(IAstModification.ReplaceNode(typecast, typecast.expression, parent))
+
+        return noModifications
+    }
+
+    override fun after(subroutine: Subroutine, parent: Node): Iterable<IAstModification> {
+        if(subroutine.parent!==parent)
+            throw FatalAstException("parent node mismatch at $subroutine")
+        return noModifications
+    }
+
+    override fun after(assignment: Assignment, parent: Node): Iterable<IAstModification> {
+        if(assignment.parent!==parent)
+            throw FatalAstException("parent node mismatch at $assignment")
+        return noModifications
+    }
+
+    override fun after(assignTarget: AssignTarget, parent: Node): Iterable<IAstModification> {
+        if(assignTarget.parent!==parent)
+            throw FatalAstException("parent node mismatch at $assignTarget")
+        return noModifications
+    }
+
+    override fun after(decl: VarDecl, parent: Node): Iterable<IAstModification> {
+        if(decl.parent!==parent)
+            throw FatalAstException("parent node mismatch at $decl")
+        return noModifications
+    }
+
+    override fun after(scope: AnonymousScope, parent: Node): Iterable<IAstModification> {
+        if(scope.parent!==parent)
+            throw FatalAstException("parent node mismatch at $scope")
+        return noModifications
+    }
+
+    override fun after(returnStmt: Return, parent: Node): Iterable<IAstModification> {
+        if(returnStmt.parent!==parent)
+            throw FatalAstException("parent node mismatch at $returnStmt")
+        return noModifications
+    }
+
+    override fun after(identifier: IdentifierReference, parent: Node): Iterable<IAstModification> {
+        if(identifier.parent!==parent)
+            throw FatalAstException("parent node mismatch at $identifier")
+        return noModifications
+    }
 }

compiler/src/prog8/compiler/astprocessing/VerifyFunctionArgTypes.kt

@@ -44,7 +44,7 @@ class VerifyFunctionArgTypes(val program: Program) : IAstVisitor {
             val firstUnknownDt = argITypes.indexOfFirst { it.isUnknown }
             if(firstUnknownDt>=0)
                 return "argument ${firstUnknownDt+1} invalid argument type"
-            val argtypes = argITypes.map { it.typeOrElse(DataType.STRUCT) }
+            val argtypes = argITypes.map { it.getOr(DataType.UNDEFINED) }
             val target = call.target.targetStatement(program)
             if (target is Subroutine) {
                 if(call.args.size != target.parameters.size)

compiler/src/prog8/compiler/functions/BuiltinFunctions.kt

@@ -4,7 +4,6 @@ import prog8.ast.IMemSizer
 import prog8.ast.Program
 import prog8.ast.base.*
 import prog8.ast.expressions.*
-import prog8.ast.statements.StructDecl
 import prog8.ast.statements.VarDecl
 import prog8.compiler.CompilerException
 import kotlin.math.*
@@ -105,7 +104,6 @@ private val functionSignatures: List<FSignature> = listOf(
     FSignature("abs"         , true, listOf(FParam("value", NumericDatatypes)), null, ::builtinAbs),      // type depends on argument
     FSignature("len"         , true, listOf(FParam("values", IterableDatatypes)), null, ::builtinLen),    // type is UBYTE or UWORD depending on actual length
     FSignature("sizeof"      , true, listOf(FParam("object", DataType.values().toSet())), DataType.UBYTE, ::builtinSizeof),
-    FSignature("offsetof"    , true, listOf(FParam("object", DataType.values().toSet())), DataType.UBYTE, ::builtinOffsetof),
         // normal functions follow:
     FSignature("sgn"         , true, listOf(FParam("value", NumericDatatypes)), DataType.BYTE, ::builtinSgn ),
     FSignature("sin"         , true, listOf(FParam("rads", setOf(DataType.FLOAT))), DataType.FLOAT) { a, p, prg, ct -> oneDoubleArg(a, p, prg, Math::sin) },
@@ -138,12 +136,13 @@ private val functionSignatures: List<FSignature> = listOf(
     FSignature("peekw"       , true, listOf(FParam("address", setOf(DataType.UWORD))), DataType.UWORD),
     FSignature("poke"        , false, listOf(FParam("address", setOf(DataType.UWORD)), FParam("value", setOf(DataType.UBYTE))), null),
     FSignature("pokew"       , false, listOf(FParam("address", setOf(DataType.UWORD)), FParam("value", setOf(DataType.UWORD))), null),
-    FSignature("fastrnd8"    , false, emptyList(), DataType.UBYTE),
     FSignature("rnd"         , false, emptyList(), DataType.UBYTE),
     FSignature("rndw"        , false, emptyList(), DataType.UWORD),
     FSignature("rndf"        , false, emptyList(), DataType.FLOAT),
     FSignature("memory"      , true, listOf(FParam("name", setOf(DataType.STR)), FParam("size", setOf(DataType.UWORD))), DataType.UWORD),
     FSignature("swap"        , false, listOf(FParam("first", NumericDatatypes), FParam("second", NumericDatatypes)), null),
+    FSignature("callfar"     , false, listOf(FParam("bank", setOf(DataType.UBYTE)), FParam("address", setOf(DataType.UWORD)), FParam("arg", setOf(DataType.UWORD))), null),
+    FSignature("callrom"     , false, listOf(FParam("bank", setOf(DataType.UBYTE)), FParam("address", setOf(DataType.UWORD)), FParam("arg", setOf(DataType.UWORD))), null),
 
 )
 
@@ -154,7 +153,7 @@ fun builtinMax(array: List<Number>): Number = array.maxByOrNull { it.toDouble()
 
 fun builtinMin(array: List<Number>): Number = array.minByOrNull { it.toDouble() }!!
 
-fun builtinSum(array: List<Number>): Number = array.sumByDouble { it.toDouble() }
+fun builtinSum(array: List<Number>): Number = array.sumOf { it.toDouble() }
 
 fun builtinAny(array: List<Number>): Number = if(array.any { it.toDouble()!=0.0 }) 1 else 0
 
@@ -165,7 +164,7 @@ fun builtinFunctionReturnType(function: String, args: List<Expression>, program:
 
     fun datatypeFromIterableArg(arglist: Expression): DataType {
         if(arglist is ArrayLiteralValue) {
-            val dt = arglist.value.map {it.inferType(program).typeOrElse(DataType.STRUCT)}.toSet()
+            val dt = arglist.value.map {it.inferType(program).getOr(DataType.UNDEFINED)}.toSet()
             if(dt.any { it !in NumericDatatypes }) {
                 throw FatalAstException("fuction $function only accepts array of numeric values")
             }
@@ -179,9 +178,9 @@ fun builtinFunctionReturnType(function: String, args: List<Expression>, program:
             val idt = arglist.inferType(program)
             if(!idt.isKnown)
                 throw FatalAstException("couldn't determine type of iterable $arglist")
-            return when(val dt = idt.typeOrElse(DataType.STRUCT)) {
+            return when(val dt = idt.getOr(DataType.UNDEFINED)) {
                 DataType.STR, in NumericDatatypes -> dt
-                in ArrayDatatypes -> ArrayElementTypes.getValue(dt)
+                in ArrayDatatypes -> ArrayToElementTypes.getValue(dt)
                 else -> throw FatalAstException("function '$function' requires one argument which is an iterable")
             }
         }
@@ -196,7 +195,7 @@ fun builtinFunctionReturnType(function: String, args: List<Expression>, program:
     return when (function) {
         "abs" -> {
             val dt = args.single().inferType(program)
-            return if(dt.typeOrElse(DataType.STRUCT) in NumericDatatypes)
+            return if(dt.isNumeric)
                 dt
             else
                 InferredTypes.InferredType.unknown()
@@ -205,7 +204,7 @@ fun builtinFunctionReturnType(function: String, args: List<Expression>, program:
             when(val dt = datatypeFromIterableArg(args.single())) {
                 DataType.STR -> InferredTypes.knownFor(DataType.UBYTE)
                 in NumericDatatypes -> InferredTypes.knownFor(dt)
-                in ArrayDatatypes -> InferredTypes.knownFor(ArrayElementTypes.getValue(dt))
+                in ArrayDatatypes -> InferredTypes.knownFor(ArrayToElementTypes.getValue(dt))
                 else -> InferredTypes.unknown()
             }
         }
@@ -288,28 +287,6 @@ private fun builtinAbs(args: List<Expression>, position: Position, program: Prog
     }
 }
 
-private fun builtinOffsetof(args: List<Expression>, position: Position, program: Program, memsizer: IMemSizer): NumericLiteralValue {
-    // 1 arg, type = anything, result type = ubyte
-    if(args.size!=1)
-        throw SyntaxError("offsetof requires one argument", position)
-    val idref = args[0] as? IdentifierReference
-        ?: throw SyntaxError("offsetof argument should be an identifier", position)
-
-    val vardecl = idref.targetVarDecl(program)!!
-    val struct = vardecl.struct
-    if (struct == null || vardecl.datatype == DataType.STRUCT)
-        throw SyntaxError("offsetof can only be used on struct members", position)
-
-    val membername = idref.nameInSource.last()
-    var offset = 0
-    for(member in struct.statements) {
-        if((member as VarDecl).name == membername)
-            return NumericLiteralValue(DataType.UBYTE, offset, position)
-        offset += memsizer.memorySize(member.datatype)
-    }
-    throw SyntaxError("undefined struct member", position)
-}
-
 private fun builtinSizeof(args: List<Expression>, position: Position, program: Program, memsizer: IMemSizer): NumericLiteralValue {
     // 1 arg, type = anything, result type = ubyte
     if(args.size!=1)
@@ -322,23 +299,14 @@ private fun builtinSizeof(args: List<Expression>, position: Position, program: P
         val target = (args[0] as IdentifierReference).targetStatement(program)
                 ?: throw CannotEvaluateException("sizeof", "no target")
 
-        fun structSize(target: StructDecl) = NumericLiteralValue(DataType.UBYTE, target.memsize(memsizer), position)
-
         return when {
-            dt.typeOrElse(DataType.STRUCT) in ArrayDatatypes -> {
+            dt.isArray -> {
                 val length = (target as VarDecl).arraysize!!.constIndex() ?: throw CannotEvaluateException("sizeof", "unknown array size")
-                val elementDt = ArrayElementTypes.getValue(dt.typeOrElse(DataType.STRUCT))
+                val elementDt = ArrayToElementTypes.getValue(dt.getOr(DataType.UNDEFINED))
                 numericLiteral(memsizer.memorySize(elementDt) * length, position)
             }
-            dt.istype(DataType.STRUCT) -> {
-                when (target) {
-                    is VarDecl -> structSize(target.struct!!)
-                    is StructDecl -> structSize(target)
-                    else -> throw CompilerException("weird struct type $target")
-                }
-            }
             dt.istype(DataType.STR) -> throw SyntaxError("sizeof str is undefined, did you mean len?", position)
-            else -> NumericLiteralValue(DataType.UBYTE, memsizer.memorySize(dt.typeOrElse(DataType.STRUCT)), position)
+            else -> NumericLiteralValue(DataType.UBYTE, memsizer.memorySize(dt.getOr(DataType.UNDEFINED)), position)
         }
     } else {
         throw SyntaxError("sizeof invalid argument type", position)
@@ -347,7 +315,7 @@ private fun builtinSizeof(args: List<Expression>, position: Position, program: P
 
 @Suppress("UNUSED_PARAMETER")
 private fun builtinLen(args: List<Expression>, position: Position, program: Program, memsizer: IMemSizer): NumericLiteralValue {
-    // note: in some cases the length is > 255 and then we have to return a UWORD type instead of a UBYTE.
+    // note: in some cases the length is > 255, and then we have to return a UWORD type instead of a UBYTE.
     if(args.size!=1)
         throw SyntaxError("len requires one argument", position)
 
@@ -373,7 +341,6 @@ private fun builtinLen(args: List<Expression>, position: Position, program: Prog
             val refLv = target.value as? StringLiteralValue ?: throw CannotEvaluateException("len", "stringsize unknown")
             NumericLiteralValue.optimalInteger(refLv.value.length, args[0].position)
         }
-        DataType.STRUCT -> throw SyntaxError("cannot use len on struct, did you mean sizeof?", args[0].position)
         in NumericDatatypes -> throw SyntaxError("cannot use len on numeric value, did you mean sizeof?", args[0].position)
         else -> throw CompilerException("weird datatype")
     }

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

@@ -11,6 +11,7 @@ internal const val subroutineFloatEvalResultVar1 = "_prog8_float_eval_result1"
 internal const val subroutineFloatEvalResultVar2 = "_prog8_float_eval_result2"
 
 internal interface IAssemblyProgram {
+    val valid: Boolean
     val name: String
-    fun assemble(options: CompilationOptions)
+    fun assemble(options: CompilationOptions): Int
 }

compiler/src/prog8/compiler/target/ICompilationTarget.kt

@@ -1,7 +1,6 @@
 package prog8.compiler.target
 
 import prog8.ast.IMemSizer
-import prog8.ast.IStringEncoding
 import prog8.ast.Program
 import prog8.ast.base.*
 import prog8.ast.expressions.IdentifierReference
@@ -9,11 +8,13 @@ import prog8.ast.expressions.NumericLiteralValue
 import prog8.ast.statements.AssignTarget
 import prog8.compiler.CompilationOptions
 import prog8.compiler.IErrorReporter
+import prog8.compiler.IStringEncoding
 import prog8.compiler.Zeropage
 import prog8.compiler.target.c64.C64MachineDefinition
-import prog8.compiler.target.c64.Petscii
+import prog8.compiler.target.cbm.Petscii
 import prog8.compiler.target.cpu6502.codegen.AsmGen
 import prog8.compiler.target.cx16.CX16MachineDefinition
+import java.io.CharConversionException
 import java.nio.file.Path
 
 
@@ -23,6 +24,8 @@ interface ICompilationTarget: IStringEncoding, IMemSizer {
     override fun encodeString(str: String, altEncoding: Boolean): List<Short>
     override fun decodeString(bytes: List<Short>, altEncoding: Boolean): String
 
+    // TODO: rename param target, and also AST node AssignTarget - *different meaning of "target"!*
+    // TODO: remove param program - can be obtained from AST node
     fun isInRegularRAM(target: AssignTarget, program: Program): Boolean {
         val memAddr = target.memoryAddress
         val arrayIdx = target.arrayindexed
@@ -69,10 +72,19 @@ interface ICompilationTarget: IStringEncoding, IMemSizer {
 internal object C64Target: ICompilationTarget {
     override val name = "c64"
     override val machine = C64MachineDefinition
-    override fun encodeString(str: String, altEncoding: Boolean) =
-            if(altEncoding) Petscii.encodeScreencode(str, true) else Petscii.encodePetscii(str, true)
+    override fun encodeString(str: String, altEncoding: Boolean): List<Short> {
+        val coded = if (altEncoding) Petscii.encodeScreencode(str, true) else Petscii.encodePetscii(str, true)
+        return coded.fold(
+            { throw it },
+            { it }
+        )
+    }
     override fun decodeString(bytes: List<Short>, altEncoding: Boolean) =
-            if(altEncoding) Petscii.decodeScreencode(bytes, true) else Petscii.decodePetscii(bytes, true)
+        try {
+            if (altEncoding) Petscii.decodeScreencode(bytes, true) else Petscii.decodePetscii(bytes, true)
+        } catch (x: CharConversionException) {
+            throw CharConversionException("can't decode string: ${x.message}")
+        }
 
     override fun memorySize(dt: DataType): Int {
         return when(dt) {
@@ -88,10 +100,19 @@ internal object C64Target: ICompilationTarget {
 internal object Cx16Target: ICompilationTarget {
     override val name = "cx16"
     override val machine = CX16MachineDefinition
-    override fun encodeString(str: String, altEncoding: Boolean) =
-            if(altEncoding) Petscii.encodeScreencode(str, true) else Petscii.encodePetscii(str, true)
+    override fun encodeString(str: String, altEncoding: Boolean): List<Short> {
+        val coded= if (altEncoding) Petscii.encodeScreencode(str, true) else Petscii.encodePetscii(str, true)
+        return coded.fold(
+            { throw it },
+            { it}
+        )
+    }
     override fun decodeString(bytes: List<Short>, altEncoding: Boolean) =
-            if(altEncoding) Petscii.decodeScreencode(bytes, true) else Petscii.decodePetscii(bytes, true)
+        try {
+            if (altEncoding) Petscii.decodeScreencode(bytes, true) else Petscii.decodePetscii(bytes, true)
+        } catch (x: CharConversionException) {
+            throw CharConversionException("can't decode string: ${x.message}")
+        }
 
     override fun memorySize(dt: DataType): Int {
         return when(dt) {

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

@@ -2,6 +2,7 @@ package prog8.compiler.target
 
 import prog8.compiler.CompilationOptions
 import prog8.compiler.Zeropage
+import java.nio.file.Path
 
 
 interface IMachineFloat {
@@ -32,6 +33,6 @@ interface IMachineDefinition {
     fun getFloat(num: Number): IMachineFloat
 
     fun importLibs(compilerOptions: CompilationOptions, compilationTargetName: String): List<String>
-    fun launchEmulator(programName: String)
+    fun launchEmulator(selectedEmulator: Int, programNameWithPath: Path)
     fun isRegularRAMaddress(address: Int): Boolean
 }

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

@@ -4,7 +4,9 @@ import prog8.compiler.*
 import prog8.compiler.target.CpuType
 import prog8.compiler.target.IMachineDefinition
 import prog8.compiler.target.IMachineFloat
+import prog8.compiler.target.cbm.viceMonListPostfix
 import java.io.IOException
+import java.nio.file.Path
 import kotlin.math.absoluteValue
 import kotlin.math.pow
 
@@ -35,11 +37,16 @@ internal object C64MachineDefinition: IMachineDefinition {
             emptyList()
     }
 
-    override fun launchEmulator(programName: String) {
+    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 $emulator...")
-            val cmdline = listOf(emulator, "-silent", "-moncommands", "$programName.vice-mon-list",
-                    "-autostartprgmode", "1", "-autostart-warp", "-autostart", programName + ".prg")
+            val cmdline = listOf(emulator, "-silent", "-moncommands", "${programNameWithPath}.$viceMonListPostfix",
+                    "-autostartprgmode", "1", "-autostart-warp", "-autostart", "${programNameWithPath}.prg")
             val processb = ProcessBuilder(cmdline).inheritIO()
             val process: Process
             try {
@@ -107,7 +114,7 @@ internal object C64MachineDefinition: IMachineDefinition {
                 }
 
                 if (options.zeropage == ZeropageType.FLOATSAFE) {
-                    // remove the zero page locations used for floating point operations from the free list
+                    // 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,

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

@@ -1,19 +1,26 @@
-package prog8.compiler.target.c64
+package prog8.compiler.target.cbm
 
 import prog8.compiler.CompilationOptions
 import prog8.compiler.OutputType
 import prog8.compiler.target.IAssemblyProgram
 import prog8.compiler.target.generatedLabelPrefix
 import java.nio.file.Path
-import kotlin.system.exitProcess
 
-class AssemblyProgram(override val name: String, outputDir: Path, private val compTarget: String) : IAssemblyProgram {
+
+internal const val viceMonListPostfix = "vice-mon-list"
+
+class AssemblyProgram(
+        override val valid: Boolean,
+        override val name: String,
+        outputDir: Path,
+        private val compTarget: String) : IAssemblyProgram {
+
     private val assemblyFile = outputDir.resolve("$name.asm")
     private val prgFile = outputDir.resolve("$name.prg")
     private val binFile = outputDir.resolve("$name.bin")
-    private val viceMonListFile = outputDir.resolve("$name.vice-mon-list")
+    private val viceMonListFile = outputDir.resolve("$name.$viceMonListPostfix")
 
-    override fun assemble(options: CompilationOptions) {
+    override fun assemble(options: CompilationOptions): Int {
         // 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",
@@ -35,13 +42,11 @@ class AssemblyProgram(override val name: String, outputDir: Path, private val co
 
         val proc = ProcessBuilder(command).inheritIO().start()
         val result = proc.waitFor()
-        if (result != 0) {
-            System.err.println("assembler failed with returncode $result")
-            exitProcess(result)
+        if (result == 0) {
+            removeGeneratedLabelsFromMonlist()
+            generateBreakpointList()
         }
-
-        removeGeneratedLabelsFromMonlist()
-        generateBreakpointList()
+        return result
     }
 
     private fun removeGeneratedLabelsFromMonlist() {

compiler/src/prog8/compiler/target/cbm/Petscii.kt

@@ -1,5 +1,9 @@
-package prog8.compiler.target.c64
+package prog8.compiler.target.cbm
 
+import prog8.Either
+import prog8.ast.antlr.escape
+import prog8.left
+import prog8.right
 import java.io.CharConversionException
 
 object Petscii {
@@ -172,7 +176,7 @@ object Petscii {
             '\u258c',    //  ▌    0xA1 -> LEFT HALF BLOCK
             '\u2584',    //  ▄    0xA2 -> LOWER HALF BLOCK
             '\u2594',    //  ▔    0xA3 -> UPPER ONE EIGHTH BLOCK
-            '_',         //  ▁    0xA4 -> LOWER ONE EIGHTH BLOCK
+            '\u2581',    //  ▁    0xA4 -> LOWER ONE EIGHTH BLOCK
             '\u258f',    //  ▏    0xA5 -> LEFT ONE EIGHTH BLOCK
             '\u2592',    //  ▒    0xA6 -> MEDIUM SHADE
             '\u2595',    //  ▕    0xA7 -> RIGHT ONE EIGHTH BLOCK
@@ -236,7 +240,7 @@ object Petscii {
             '\u258c',    //  ▌    0xE1 -> LEFT HALF BLOCK
             '\u2584',    //  ▄    0xE2 -> LOWER HALF BLOCK
             '\u2594',    //  ▔    0xE3 -> UPPER ONE EIGHTH BLOCK
-            '_',         //  ▁    0xE4 -> LOWER ONE EIGHTH BLOCK
+            '\u2581',    //  ▁    0xE4 -> LOWER ONE EIGHTH BLOCK
             '\u258f',    //  ▏    0xE5 -> LEFT ONE EIGHTH BLOCK
             '\u2592',    //  ▒    0xE6 -> MEDIUM SHADE
             '\u2595',    //  ▕    0xE7 -> RIGHT ONE EIGHTH BLOCK
@@ -431,7 +435,7 @@ object Petscii {
             '\u258c',    //  ▌    0xA1 -> LEFT HALF BLOCK
             '\u2584',    //  ▄    0xA2 -> LOWER HALF BLOCK
             '\u2594',    //  ▔    0xA3 -> UPPER ONE EIGHTH BLOCK
-            '_',         //  ▁    0xA4 -> LOWER ONE EIGHTH BLOCK
+            '\u2581',    //  ▁    0xA4 -> LOWER ONE EIGHTH BLOCK
             '\u258f',    //  ▏    0xA5 -> LEFT ONE EIGHTH BLOCK
             '\u2592',    //  ▒    0xA6 -> MEDIUM SHADE
             '\u2595',    //  ▕    0xA7 -> RIGHT ONE EIGHTH BLOCK
@@ -495,7 +499,7 @@ object Petscii {
             '\u258c',    //  ▌    0xE1 -> LEFT HALF BLOCK
             '\u2584',    //  ▄    0xE2 -> LOWER HALF BLOCK
             '\u2594',    //  ▔    0xE3 -> UPPER ONE EIGHTH BLOCK
-            '_',         //  ▁    0xE4 -> LOWER ONE EIGHTH BLOCK
+            '\u2581',    //  ▁    0xE4 -> LOWER ONE EIGHTH BLOCK
             '\u258f',    //  ▏    0xE5 -> LEFT ONE EIGHTH BLOCK
             '\u2592',    //  ▒    0xE6 -> MEDIUM SHADE
             '\u2595',    //  ▕    0xE7 -> RIGHT ONE EIGHTH BLOCK
@@ -626,7 +630,7 @@ object Petscii {
             '\u258c',    //  ▌    0x61 -> LEFT HALF BLOCK
             '\u2584',    //  ▄    0x62 -> LOWER HALF BLOCK
             '\u2594',    //  ▔    0x63 -> UPPER ONE EIGHTH BLOCK
-            '_',         //  ▁    0x64 -> LOWER ONE EIGHTH BLOCK
+            '\u2581',    //  ▁    0x64 -> LOWER ONE EIGHTH BLOCK
             '\u258f',    //  ▏    0x65 -> LEFT ONE EIGHTH BLOCK
             '\u2592',    //  ▒    0x66 -> MEDIUM SHADE
             '\u2595',    //  ▕    0x67 -> RIGHT ONE EIGHTH BLOCK
@@ -885,7 +889,7 @@ object Petscii {
             '\u258c',    //  ▌    0x61 -> LEFT HALF BLOCK
             '\u2584',    //  ▄    0x62 -> LOWER HALF BLOCK
             '\u2594',    //  ▔    0x63 -> UPPER ONE EIGHTH BLOCK
-            '_',         //  ▁    0x64 -> LOWER ONE EIGHTH BLOCK
+            '\u2581',    //  ▁    0x64 -> LOWER ONE EIGHTH BLOCK
             '\u258f',    //  ▏    0x65 -> LEFT ONE EIGHTH BLOCK
             '\u2592',    //  ▒    0x66 -> MEDIUM SHADE
             '\u2595',    //  ▕    0x67 -> RIGHT ONE EIGHTH BLOCK
@@ -1049,54 +1053,103 @@ object Petscii {
     private val encodingScreencodeLowercase = decodingScreencodeLowercase.withIndex().associate{it.value to it.index}
     private val encodingScreencodeUppercase = decodingScreencodeUppercase.withIndex().associate{it.value to it.index}
 
+    private fun replaceSpecial(chr: Char): Char =
+        // characters often used in C like source code can be translated with a little fantasy:
+        when(chr) {
+            '^' -> '↑'
+            '_' -> '▁'
+            '{' -> '┤'
+            '}' -> '├'
+            '|' -> '│'
+            '\\' -> '╲'
+            else -> chr
+        }
 
-    fun encodePetscii(text: String, lowercase: Boolean = false): List<Short> {
-        val lookup = if(lowercase) encodingPetsciiLowercase else encodingPetsciiUppercase
-        return text.map {
-            val petscii = lookup[it]
-            petscii?.toShort() ?: when (it) {
+    fun encodePetscii(text: String, lowercase: Boolean = false): Either<CharConversionException, List<Short>> {
+        fun encodeChar(chr3: Char, lowercase: Boolean): Short {
+            val chr = replaceSpecial(chr3)
+            val screencode = if(lowercase) encodingPetsciiLowercase[chr] else encodingPetsciiUppercase[chr]
+            return screencode?.toShort() ?: when (chr) {
                 '\u0000' -> 0.toShort()
                 in '\u8000'..'\u80ff' -> {
                     // special case: take the lower 8 bit hex value directly
-                    (it.toInt() - 0x8000).toShort()
+                    (chr.code - 0x8000).toShort()
                 }
                 else -> {
                     val case = if (lowercase) "lower" else "upper"
-                    throw CharConversionException("no ${case}case Petscii character for '$it' (${it.toShort()})")
+                    throw CharConversionException("no ${case}Petscii character for '${escape(chr.toString())}' (${chr.code})")
                 }
             }
         }
+
+        return try {
+            right(text.map {
+                try {
+                    encodeChar(it, lowercase)
+                } catch (x: CharConversionException) {
+                    encodeChar(it, !lowercase)
+                }
+            })
+        } catch(cx: CharConversionException) {
+            left(cx)
+        }
     }
 
     fun decodePetscii(petscii: Iterable<Short>, lowercase: Boolean = false): String {
-        val decodeTable = if(lowercase) decodingPetsciiLowercase else decodingPetsciiUppercase
-        return petscii.map { decodeTable[it.toInt()] }.joinToString("")
+        return petscii.map {
+            val code = it.toInt()
+            try {
+                if(lowercase) decodingPetsciiLowercase[code] else decodingPetsciiUppercase[code]
+            } catch(x: CharConversionException) {
+                // TODO this CharConversionException can never occur?? also clean up ICompilationTarget.decodeString?
+                if(lowercase) decodingPetsciiUppercase[code] else decodingPetsciiLowercase[code]
+            }
+        }.joinToString("")
     }
 
-    fun encodeScreencode(text: String, lowercase: Boolean = false): List<Short> {
-        val lookup = if(lowercase) encodingScreencodeLowercase else encodingScreencodeUppercase
-        return text.map{
-            val screencode = lookup[it]
-            screencode?.toShort() ?: when (it) {
+    fun encodeScreencode(text: String, lowercase: Boolean = false): Either<CharConversionException, List<Short>> {
+        fun encodeChar(chr3: Char, lowercase: Boolean): Short {
+            val chr = replaceSpecial(chr3)
+            val screencode = if(lowercase) encodingScreencodeLowercase[chr] else encodingScreencodeUppercase[chr]
+            return screencode?.toShort() ?: when (chr) {
                 '\u0000' -> 0.toShort()
                 in '\u8000'..'\u80ff' -> {
                     // special case: take the lower 8 bit hex value directly
-                    (it.toInt() - 0x8000).toShort()
+                    (chr.code - 0x8000).toShort()
                 }
                 else -> {
                     val case = if (lowercase) "lower" else "upper"
-                    throw CharConversionException("no ${case}Screencode character for '$it' (${it.toShort()})")
+                    throw CharConversionException("no ${case}Screencode character for '${escape(chr.toString())}' (${chr.code})")
                 }
             }
         }
+
+        return try {
+            right(text.map {
+                try {
+                    encodeChar(it, lowercase)
+                } catch (x: CharConversionException) {
+                    encodeChar(it, !lowercase)
+                }
+            })
+        } catch(cx: CharConversionException) {
+            left(cx)
+        }
     }
 
     fun decodeScreencode(screencode: Iterable<Short>, lowercase: Boolean = false): String {
-        val decodeTable = if(lowercase) decodingScreencodeLowercase else decodingScreencodeUppercase
-        return screencode.map { decodeTable[it.toInt()] }.joinToString("")
+        return screencode.map {
+            val code = it.toInt()
+            try {
+                if (lowercase) decodingScreencodeLowercase[code] else decodingScreencodeUppercase[code]
+            } catch (x: CharConversionException) {
+                // TODO this CharConversionException can never occur?? also clean up ICompilationTarget.decodeString?
+                if (lowercase) decodingScreencodeUppercase[code] else decodingScreencodeLowercase[code]
+            }
+        }.joinToString("")
     }
 
-    fun petscii2scr(petscii_code: Short, inverseVideo: Boolean): Short {
+    fun petscii2scr(petscii_code: Short, inverseVideo: Boolean): Either<CharConversionException, Short> {
         val code = when {
             petscii_code <= 0x1f -> petscii_code + 128
             petscii_code <= 0x3f -> petscii_code.toInt()
@@ -1106,14 +1159,14 @@ object Petscii {
             petscii_code <= 0xbf -> petscii_code - 64
             petscii_code <= 0xfe -> petscii_code - 128
             petscii_code == 255.toShort() -> 95
-            else -> throw CharConversionException("petscii code out of range")
+            else -> return left(CharConversionException("petscii code out of range"))
         }
         if(inverseVideo)
-            return (code or 0x80).toShort()
-        return code.toShort()
+            return right((code or 0x80).toShort())
+        return right(code.toShort())
     }
 
-    fun scr2petscii(screencode: Short): Short {
+    fun scr2petscii(screencode: Short): Either<CharConversionException, Short> {
         val petscii = when {
             screencode <= 0x1f -> screencode + 64
             screencode <= 0x3f -> screencode.toInt()
@@ -1124,8 +1177,8 @@ object Petscii {
             screencode <= 0xbf -> screencode - 128
             screencode <= 0xfe -> screencode - 64
             screencode == 255.toShort() -> 191
-            else -> throw CharConversionException("screencode out of range")
+            else -> return left(CharConversionException("screencode out of range"))
         }
-        return petscii.toShort()
+        return right(petscii.toShort())
     }
 }

compiler/src/prog8/compiler/target/cpu6502/codegen/AsmGen.kt

@@ -1,5 +1,6 @@
 package prog8.compiler.target.cpu6502.codegen
 
+import com.github.michaelbull.result.*
 import prog8.ast.*
 import prog8.ast.antlr.escape
 import prog8.ast.base.*
@@ -9,16 +10,16 @@ import prog8.compiler.*
 import prog8.compiler.functions.BuiltinFunctions
 import prog8.compiler.functions.FSignature
 import prog8.compiler.target.*
-import prog8.compiler.target.c64.AssemblyProgram
-import prog8.compiler.target.c64.Petscii
+import prog8.compiler.target.cbm.AssemblyProgram
 import prog8.compiler.target.cpu6502.codegen.assignment.AsmAssignment
 import prog8.compiler.target.cpu6502.codegen.assignment.AssignmentAsmGen
-import java.io.CharConversionException
+import prog8.optimizer.CallGraph
 import java.nio.file.Path
-import java.nio.file.Paths
 import java.time.LocalDate
 import java.time.LocalDateTime
 import java.util.*
+import kotlin.io.path.Path
+import kotlin.io.path.absolute
 import kotlin.math.absoluteValue
 
 
@@ -31,7 +32,8 @@ internal class AsmGen(private val program: Program,
 
     // for expressions and augmented assignments:
     val optimizedByteMultiplications = setOf(3,5,6,7,9,10,11,12,13,14,15,20,25,40,50,80,100)
-    val optimizedWordMultiplications = setOf(3,5,6,7,9,10,12,15,20,25,40,50,80,100,320)
+    val optimizedWordMultiplications = setOf(3,5,6,7,9,10,12,15,20,25,40,50,80,100,320,640)
+    private val callGraph = CallGraph(program)
 
     private val assemblyLines = mutableListOf<String>()
     private val globalFloatConsts = mutableMapOf<Double, String>()     // all float values in the entire program (value -> varname)
@@ -55,10 +57,10 @@ internal class AsmGen(private val program: Program,
         println("Generating assembly code... ")
 
         header()
-        val allBlocks = program.allBlocks()
+        val allBlocks = program.allBlocks
         if(allBlocks.first().name != "main")
             throw AssemblyError("first block should be 'main'")
-        for(b in program.allBlocks())
+        for(b in program.allBlocks)
             block2asm(b)
 
         for(removal in removals.toList()) {
@@ -86,7 +88,11 @@ internal class AsmGen(private val program: Program,
             }
         }
 
-        return AssemblyProgram(program.name, outputDir, compTarget.name)
+        return if(errors.noErrors())
+            AssemblyProgram(true, program.name, outputDir, compTarget.name)
+        else {
+            AssemblyProgram(false, "<error>", outputDir, compTarget.name)
+        }
     }
 
     internal fun isTargetCpu(cpu: CpuType) = compTarget.machine.cpu == cpu
@@ -128,7 +134,7 @@ internal class AsmGen(private val program: Program,
                 out("* = ${program.actualLoadAddress.toHex()}")
                 val year = LocalDate.now().year
                 out("  .word  (+), $year")
-                out("  .null  $9e, format(' %d ', _prog8_entrypoint), $3a, $8f, ' prog8 by idj'")
+                out("  .null  $9e, format(' %d ', _prog8_entrypoint), $3a, $8f, ' prog8'")
                 out("+\t.word  0")
                 out("_prog8_entrypoint\t; assembly code starts here\n")
                 if(!options.noSysInit)
@@ -157,7 +163,16 @@ internal class AsmGen(private val program: Program,
                 pha""")
         }
 
-        jmp("main.start")
+        // make sure that on the cx16 and c64, basic rom is banked in again when we exit the program
+        when(compTarget.name) {
+            Cx16Target.name -> {
+                if(options.floats)
+                    out("  lda  #4 |  sta  $01")    // to use floats, make sure Basic rom is banked in
+                out("  jsr  main.start |  lda  #4 |  sta  $01 |  rts")
+            }
+            C64Target.name -> out("  jsr  main.start |  lda  #31 |  sta  $01 |  rts")
+            else -> jmp("main.start")
+        }
     }
 
     private fun slaballocations() {
@@ -220,7 +235,7 @@ internal class AsmGen(private val program: Program,
 
     private fun assignInitialValueToVar(decl: VarDecl, variableName: List<String>) {
         val asmName = asmVariableName(variableName)
-        assignmentAsmGen.assignExpressionToVariable(decl.value!!, asmName, decl.datatype, decl.definingSubroutine())
+        assignmentAsmGen.assignExpressionToVariable(decl.value!!, asmName, decl.datatype, decl.definingSubroutine)
     }
 
     private var generatedLabelSequenceNumber: Int = 0
@@ -246,15 +261,6 @@ internal class AsmGen(private val program: Program,
         } else assemblyLines.add(fragment)
     }
 
-    private fun encode(str: String, altEncoding: Boolean): List<Short> {
-        try {
-            val bytes = if (altEncoding) Petscii.encodeScreencode(str, true) else Petscii.encodePetscii(str, true)
-            return bytes.plus(0)
-        } catch(x: CharConversionException) {
-            throw AssemblyError("There was a problem converting a string to the target machine's char encoding: ${x.message}")
-        }
-    }
-
     private fun zeropagevars2asm(statements: List<Statement>) {
         out("; vars allocated on zeropage")
         val variables = statements.filterIsInstance<VarDecl>().filter { it.type==VarDeclType.VAR }
@@ -290,10 +296,9 @@ internal class AsmGen(private val program: Program,
             DataType.UWORD -> out("$name\t.word  0")
             DataType.WORD -> out("$name\t.sint  0")
             DataType.FLOAT -> out("$name\t.byte  0,0,0,0,0  ; float")
-            DataType.STRUCT -> {}       // is flattened
             DataType.STR -> {
                 val str = decl.value as StringLiteralValue
-                outputStringvar(decl, encode(str.value, str.altEncoding))
+                outputStringvar(decl, compTarget.encodeString(str.value, str.altEncoding).plus(0))
             }
             DataType.ARRAY_UB -> {
                 val data = makeArrayFillDataUnsigned(decl)
@@ -352,6 +357,9 @@ internal class AsmGen(private val program: Program,
                 for (f in array.zip(floatFills))
                     out("  .byte  ${f.second}  ; float ${f.first}")
             }
+            else -> {
+                throw AssemblyError("weird dt")
+            }
         }
     }
 
@@ -379,38 +387,28 @@ internal class AsmGen(private val program: Program,
         out("\n; non-zeropage variables")
         val vars = statements.filterIsInstance<VarDecl>().filter { it.type==VarDeclType.VAR }
 
-        // first output the flattened struct member variables *in order*
-        // after that, the other variables sorted by their datatype
-
-        val (structMembers, normalVars) = vars.partition { it.struct!=null }
-        structMembers.forEach { vardecl2asm(it) }
-
-        // special treatment for string types: merge strings that are identical
-        val encodedstringVars = normalVars
+        val encodedstringVars = vars
                 .filter {it.datatype == DataType.STR }
                 .map {
                     val str = it.value as StringLiteralValue
-                    it to encode(str.value, str.altEncoding)
+                    it to compTarget.encodeString(str.value, str.altEncoding).plus(0)
                 }
-                .groupBy({it.second}, {it.first})
-        for((encoded, variables) in encodedstringVars) {
-            variables.dropLast(1).forEach { out(it.name) }
-            val lastvar = variables.last()
-            outputStringvar(lastvar, encoded)
+        for((decl, variables) in encodedstringVars) {
+            outputStringvar(decl, variables)
         }
 
         // non-string variables
-        normalVars.filter{ it.datatype != DataType.STR }.sortedBy { it.datatype }.forEach {
+        vars.filter{ it.datatype != DataType.STR }.sortedBy { it.datatype }.forEach {
             if(it.makeScopedName(it.name) !in allocatedZeropageVariables)
                 vardecl2asm(it)
         }
     }
 
-    private fun outputStringvar(lastvar: VarDecl, encoded: List<Short>) {
-        val sv = lastvar.value as StringLiteralValue
+    private fun outputStringvar(strdecl: VarDecl, bytes: List<Short>) {
+        val sv = strdecl.value as StringLiteralValue
         val altEncoding = if(sv.altEncoding) "@" else ""
-        out("${lastvar.name}\t; ${lastvar.datatype} $altEncoding\"${escape(sv.value).replace("\u0000", "<NULL>")}\"")
-        val outputBytes = encoded.map { "$" + it.toString(16).padStart(2, '0') }
+        out("${strdecl.name}\t; ${strdecl.datatype} $altEncoding\"${escape(sv.value).replace("\u0000", "<NULL>")}\"")
+        val outputBytes = bytes.map { "$" + it.toString(16).padStart(2, '0') }
         for (chunk in outputBytes.chunked(16))
             out("  .byte  " + chunk.joinToString())
     }
@@ -437,10 +435,10 @@ internal class AsmGen(private val program: Program,
                         "$" + it.number.toInt().toString(16).padStart(4, '0')
                     }
                     is AddressOf -> {
-                        it.identifier.firstStructVarName(program) ?: asmSymbolName(it.identifier)
+                        asmSymbolName(it.identifier)
                     }
                     is IdentifierReference -> {
-                        it.firstStructVarName(program) ?: asmSymbolName(it)
+                        asmSymbolName(it)
                     }
                     else -> throw AssemblyError("weird array elt dt")
                 }
@@ -502,69 +500,107 @@ internal class AsmGen(private val program: Program,
     }
 
     internal fun asmSymbolName(identifier: IdentifierReference): String {
-        return if(identifier.memberOfStruct(program)!=null) {
-            val name = identifier.targetVarDecl(program)!!.name
-            fixNameSymbols(name)
+        if(identifier.nameInSource.size==2 && identifier.nameInSource[0]=="prog8_slabs")
+            return identifier.nameInSource.joinToString(".")
+
+        val tgt2 = identifier.targetStatement(program)
+        if(tgt2==null && (identifier.nameInSource[0].startsWith("_prog8") || identifier.nameInSource[0].startsWith("prog8")))
+            return identifier.nameInSource.joinToString(".")
+
+        val target = identifier.targetStatement(program)!!
+        val targetScope = target.definingSubroutine
+        val identScope = identifier.definingSubroutine
+        return if(targetScope !== identScope) {
+            val scopedName = getScopedSymbolNameForTarget(identifier.nameInSource.last(), target)
+            if(target is Label) {
+                // make labels locally scoped in the asm. Is slightly problematic, see github issue #62
+                val last = scopedName.removeLast()
+                scopedName.add("_$last")
+            }
+            fixNameSymbols(scopedName.joinToString("."))
         } else {
-            fixNameSymbols(identifier.nameInSource.joinToString("."))
+            if(target is Label) {
+                // make labels locally scoped in the asm. Is slightly problematic, see github issue #62
+                val scopedName = identifier.nameInSource.toMutableList()
+                val last = scopedName.removeLast()
+                scopedName.add("_$last")
+                fixNameSymbols(scopedName.joinToString("."))
+            }
+            else fixNameSymbols(identifier.nameInSource.joinToString("."))
         }
     }
 
+    internal fun asmVariableName(identifier: IdentifierReference) =
+        fixNameSymbols(identifier.nameInSource.joinToString("."))
+
+    private fun getScopedSymbolNameForTarget(actualName: String, target: Statement): MutableList<String> {
+        val scopedName = mutableListOf(actualName)
+        var node: Node = target
+        while (node !is Block) {
+            node = node.parent
+            if(node is INameScope) {
+                scopedName.add(0, node.name)
+            }
+        }
+        return scopedName
+    }
+
     internal fun asmSymbolName(regs: RegisterOrPair): String =
-        if(regs in Cx16VirtualRegisters)
-            "cx16." + regs.toString().toLowerCase()
+        if (regs in Cx16VirtualRegisters)
+            "cx16." + regs.toString().lowercase()
         else
             throw AssemblyError("no symbol name for register $regs")
 
-    internal fun asmVariableName(identifier: IdentifierReference): String {
-        return if(identifier.memberOfStruct(program)!=null) {
-            val name = identifier.targetVarDecl(program)!!.name
-            fixNameSymbols(name)
-        } else {
-            fixNameSymbols(identifier.nameInSource.joinToString("."))
-        }
-    }
-
     internal fun asmSymbolName(name: String) = fixNameSymbols(name)
     internal fun asmVariableName(name: String) = fixNameSymbols(name)
     internal fun asmSymbolName(name: Iterable<String>) = fixNameSymbols(name.joinToString("."))
     internal fun asmVariableName(name: Iterable<String>) = fixNameSymbols(name.joinToString("."))
 
 
-    internal fun loadByteFromPointerIntoA(pointervar: IdentifierReference): Pair<Boolean, String> {
-        // returns if the pointer is already on the ZP itself or not (in the latter case SCRATCH_W1 is used as intermediary)
-        val sourceName = asmVariableName(pointervar)
-        val vardecl = pointervar.targetVarDecl(program)!!
-        val scopedName = vardecl.makeScopedName(vardecl.name)
-        if (isTargetCpu(CpuType.CPU65c02)) {
-            return if (isZpVar(scopedName)) {
-                // pointervar is already in the zero page, no need to copy
-                out("  lda  ($sourceName)")
-                Pair(true, sourceName)
-            } else {
-                out("""
-                    lda  $sourceName
-                    ldy  $sourceName+1
-                    sta  P8ZP_SCRATCH_W1
-                    sty  P8ZP_SCRATCH_W1+1
-                    lda  (P8ZP_SCRATCH_W1)""")
-                Pair(false, sourceName)
+    internal fun loadByteFromPointerIntoA(pointervar: IdentifierReference): String {
+        // returns the source name of the zero page pointervar if it's already in the ZP,
+        // otherwise returns "P8ZP_SCRATCH_W1" which is the intermediary
+        when (val target = pointervar.targetStatement(program)) {
+            is Label -> {
+                val sourceName = asmSymbolName(pointervar)
+                out("  lda  $sourceName")
+                return sourceName
             }
-        } else {
-            return if (isZpVar(scopedName)) {
-                // pointervar is already in the zero page, no need to copy
-                out("  ldy  #0 |  lda  ($sourceName),y")
-                Pair(true, sourceName)
-            } else {
-                out("""
-                    lda  $sourceName
-                    ldy  $sourceName+1
-                    sta  P8ZP_SCRATCH_W1
-                    sty  P8ZP_SCRATCH_W1+1
-                    ldy  #0
-                    lda  (P8ZP_SCRATCH_W1),y""")
-                Pair(false, sourceName)
+            is VarDecl -> {
+                val sourceName = asmVariableName(pointervar)
+                val scopedName = target.makeScopedName(target.name)
+                if (isTargetCpu(CpuType.CPU65c02)) {
+                    return if (isZpVar(scopedName)) {
+                        // pointervar is already in the zero page, no need to copy
+                        out("  lda  ($sourceName)")
+                        sourceName
+                    } else {
+                        out("""
+                            lda  $sourceName
+                            ldy  $sourceName+1
+                            sta  P8ZP_SCRATCH_W1
+                            sty  P8ZP_SCRATCH_W1+1
+                            lda  (P8ZP_SCRATCH_W1)""")
+                        "P8ZP_SCRATCH_W1"
+                    }
+                } else {
+                    return if (isZpVar(scopedName)) {
+                        // pointervar is already in the zero page, no need to copy
+                        out("  ldy  #0 |  lda  ($sourceName),y")
+                        sourceName
+                    } else {
+                        out("""
+                            lda  $sourceName
+                            ldy  $sourceName+1
+                            sta  P8ZP_SCRATCH_W1
+                            sty  P8ZP_SCRATCH_W1+1
+                            ldy  #0
+                            lda  (P8ZP_SCRATCH_W1),y""")
+                        "P8ZP_SCRATCH_W1"
+                    }
+                }
             }
+            else -> throw AssemblyError("invalid pointervar")
         }
     }
 
@@ -671,7 +707,7 @@ internal class AsmGen(private val program: Program,
         when(stmt) {
             is ParameterVarDecl -> { /* subroutine parameter vardecls don't get any special treatment here */ }
             is VarDecl -> translate(stmt)
-            is StructDecl, is NopStatement -> {}
+            is NopStatement -> {}
             is Directive -> translate(stmt)
             is Return -> translate(stmt)
             is Subroutine -> translateSubroutine(stmt)
@@ -708,14 +744,16 @@ internal class AsmGen(private val program: Program,
         }
     }
 
-    internal fun loadScaledArrayIndexIntoRegister(expr: ArrayIndexedExpression,
-                                                  elementDt: DataType,
-                                                  register: CpuRegister,
-                                                  addOneExtra: Boolean=false) {
-        val reg = register.toString().toLowerCase()
+    internal fun loadScaledArrayIndexIntoRegister(
+        expr: ArrayIndexedExpression,
+        elementDt: DataType,
+        register: CpuRegister,
+        addOneExtra: Boolean = false
+    ) {
+        val reg = register.toString().lowercase()
         val indexnum = expr.indexer.constIndex()
-        if(indexnum!=null) {
-            val indexValue = indexnum * compTarget.memorySize(elementDt) + if(addOneExtra) 1 else 0
+        if (indexnum != null) {
+            val indexValue = indexnum * compTarget.memorySize(elementDt) + if (addOneExtra) 1 else 0
             out("  ld$reg  #$indexValue")
             return
         }
@@ -724,35 +762,40 @@ internal class AsmGen(private val program: Program,
             ?: throw AssemblyError("array indexer should have been replaced with a temp var @ ${expr.indexer.position}")
 
         val indexName = asmVariableName(indexVar)
-        if(addOneExtra) {
+        if (addOneExtra) {
             // add 1 to the result
-            when(elementDt) {
+            when (elementDt) {
                 in ByteDatatypes -> {
                     out("  ldy  $indexName |  iny")
-                    when(register) {
+                    when (register) {
                         CpuRegister.A -> out(" tya")
                         CpuRegister.X -> out(" tyx")
-                        CpuRegister.Y -> {}
+                        CpuRegister.Y -> {
+                        }
                     }
                 }
                 in WordDatatypes -> {
                     out("  lda  $indexName |  sec |  rol a")
-                    when(register) {
-                        CpuRegister.A -> {}
+                    when (register) {
+                        CpuRegister.A -> {
+                        }
                         CpuRegister.X -> out(" tax")
                         CpuRegister.Y -> out(" tay")
                     }
                 }
                 DataType.FLOAT -> {
-                    require(compTarget.memorySize(DataType.FLOAT)==5)
-                    out("""
+                    require(compTarget.memorySize(DataType.FLOAT) == 5)
+                    out(
+                        """
                                 lda  $indexName
                                 asl  a
                                 asl  a
                                 sec
-                                adc  $indexName""")
-                    when(register) {
-                        CpuRegister.A -> {}
+                                adc  $indexName"""
+                    )
+                    when (register) {
+                        CpuRegister.A -> {
+                        }
                         CpuRegister.X -> out(" tax")
                         CpuRegister.Y -> out(" tay")
                     }
@@ -760,26 +803,30 @@ internal class AsmGen(private val program: Program,
                 else -> throw AssemblyError("weird dt")
             }
         } else {
-            when(elementDt) {
+            when (elementDt) {
                 in ByteDatatypes -> out("  ld$reg  $indexName")
                 in WordDatatypes -> {
                     out("  lda  $indexName |  asl a")
-                    when(register) {
-                        CpuRegister.A -> {}
+                    when (register) {
+                        CpuRegister.A -> {
+                        }
                         CpuRegister.X -> out(" tax")
                         CpuRegister.Y -> out(" tay")
                     }
                 }
                 DataType.FLOAT -> {
-                    require(compTarget.memorySize(DataType.FLOAT)==5)
-                    out("""
+                    require(compTarget.memorySize(DataType.FLOAT) == 5)
+                    out(
+                        """
                                 lda  $indexName
                                 asl  a
                                 asl  a
                                 clc
-                                adc  $indexName""")
-                    when(register) {
-                        CpuRegister.A -> {}
+                                adc  $indexName"""
+                    )
+                    when (register) {
+                        CpuRegister.A -> {
+                        }
                         CpuRegister.X -> out(" tax")
                         CpuRegister.Y -> out(" tay")
                     }
@@ -821,11 +868,20 @@ internal class AsmGen(private val program: Program,
 
 
     private fun translateSubroutine(sub: Subroutine) {
+        var onlyVariables = false
+
         if(sub.inline) {
-            if(options.optimize)
-                return      // inline subroutines don't exist anymore on their own
+            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
+            }
             else if(sub.amountOfRtsInAsm()==0) {
-                // make sure the NOT INLINED subroutine actually does an rts at the end
+                // make sure the NOT INLINED subroutine actually does a rts at the end
                 sub.statements.add(Return(null, Position.DUMMY))
             }
         }
@@ -840,7 +896,7 @@ internal class AsmGen(private val program: Program,
 
             // asmsub with most likely just an inline asm in it
             out("${sub.name}\t.proc")
-            sub.statements.forEach{ translate(it) }
+            sub.statements.forEach { translate(it) }
             out("  .pend\n")
         } else {
             // regular subroutine
@@ -849,10 +905,10 @@ internal class AsmGen(private val program: Program,
             memdefs2asm(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") {
+            if(sub.name=="start" && sub.definingBlock.name=="main") {
                 out("; program startup initialization")
                 out("  cld")
-                program.allBlocks().forEach {
+                program.allBlocks.forEach {
                     if(it.statements.filterIsInstance<VarDecl>().any { vd->vd.value!=null && vd.type==VarDeclType.VAR && vd.datatype in NumericDatatypes})
                         out("  jsr  ${it.name}.prog8_init_vars")
                 }
@@ -864,8 +920,10 @@ internal class AsmGen(private val program: Program,
                     clc""")
             }
 
-            out("; statements")
-            sub.statements.forEach{ translate(it) }
+            if(!onlyVariables) {
+                out("; statements")
+                sub.statements.forEach { translate(it) }
+            }
 
             for(removal in removals.toList()) {
                 if(removal.second==sub) {
@@ -875,7 +933,15 @@ internal class AsmGen(private val program: Program,
             }
 
             out("; variables")
-            out("; register saves")
+            for((dt, name, addr) in sub.asmGenInfo.extraVars) {
+                if(addr!=null)
+                    out("$name = $addr")
+                else when(dt) {
+                    DataType.UBYTE -> out("$name    .byte  0")
+                    DataType.UWORD -> out("$name    .word  0")
+                    else -> throw AssemblyError("weird dt")
+                }
+            }
             if(sub.asmGenInfo.usedRegsaveA)
                 out("_prog8_regsaveA     .byte  0")
             if(sub.asmGenInfo.usedRegsaveX)
@@ -883,9 +949,9 @@ internal class AsmGen(private val program: Program,
             if(sub.asmGenInfo.usedRegsaveY)
                 out("_prog8_regsaveY     .byte  0")
             if(sub.asmGenInfo.usedFloatEvalResultVar1)
-                out("$subroutineFloatEvalResultVar1    .byte 0,0,0,0,0")
+                out("$subroutineFloatEvalResultVar1    .byte  0,0,0,0,0")
             if(sub.asmGenInfo.usedFloatEvalResultVar2)
-                out("$subroutineFloatEvalResultVar2    .byte 0,0,0,0,0")
+                out("$subroutineFloatEvalResultVar2    .byte  0,0,0,0,0")
             vardecls2asm(sub.statements)
             out("  .pend\n")
         }
@@ -920,7 +986,11 @@ internal class AsmGen(private val program: Program,
         checkBooleanExpression(stmt.condition)  // we require the condition to be of the form  'x <comparison> <value>'
         val booleanCondition = stmt.condition as BinaryExpression
 
-        if (stmt.elsepart.containsNoCodeNorVars()) {
+        // DISABLED FOR NOW:
+//        if(!booleanCondition.left.isSimple || !booleanCondition.right.isSimple)
+//            throw AssemblyError("both operands for if comparison expression should have been simplified")
+
+        if (stmt.elsepart.containsNoCodeNorVars) {
             // empty else
             val endLabel = makeLabel("if_end")
             expressionsAsmGen.translateComparisonExpressionWithJumpIfFalse(booleanCondition, endLabel)
@@ -966,11 +1036,11 @@ internal class AsmGen(private val program: Program,
                     iterations == 0 -> {}
                     iterations <= 256 -> {
                         out("  lda  #${iterations and 255}")
-                        repeatByteCountInA(iterations, repeatLabel, endLabel, stmt.body)
+                        repeatByteCountInA(iterations, repeatLabel, endLabel, stmt)
                     }
                     else -> {
                         out("  lda  #<${iterations} |  ldy  #>${iterations}")
-                        repeatWordCountInAY(iterations, repeatLabel, endLabel, stmt.body)
+                        repeatWordCountInAY(iterations, repeatLabel, endLabel, stmt)
                     }
                 }
             }
@@ -980,11 +1050,11 @@ internal class AsmGen(private val program: Program,
                 when(vardecl.datatype) {
                     DataType.UBYTE, DataType.BYTE -> {
                         assignVariableToRegister(name, RegisterOrPair.A)
-                        repeatByteCountInA(null, repeatLabel, endLabel, stmt.body)
+                        repeatByteCountInA(null, repeatLabel, endLabel, stmt)
                     }
                     DataType.UWORD, DataType.WORD -> {
                         assignVariableToRegister(name, RegisterOrPair.AY)
-                        repeatWordCountInAY(null, repeatLabel, endLabel, stmt.body)
+                        repeatWordCountInAY(null, repeatLabel, endLabel, stmt)
                     }
                     else -> throw AssemblyError("invalid loop variable datatype $vardecl")
                 }
@@ -993,14 +1063,14 @@ internal class AsmGen(private val program: Program,
                 val dt = stmt.iterations!!.inferType(program)
                 if(!dt.isKnown)
                     throw AssemblyError("unknown dt")
-                when (dt.typeOrElse(DataType.STRUCT)) {
+                when (dt.getOr(DataType.UNDEFINED)) {
                     in ByteDatatypes -> {
                         assignExpressionToRegister(stmt.iterations!!, RegisterOrPair.A)
-                        repeatByteCountInA(null, repeatLabel, endLabel, stmt.body)
+                        repeatByteCountInA(null, repeatLabel, endLabel, stmt)
                     }
                     in WordDatatypes -> {
                         assignExpressionToRegister(stmt.iterations!!, RegisterOrPair.AY)
-                        repeatWordCountInAY(null, repeatLabel, endLabel, stmt.body)
+                        repeatWordCountInAY(null, repeatLabel, endLabel, stmt)
                     }
                     else -> throw AssemblyError("invalid loop expression datatype $dt")
                 }
@@ -1010,13 +1080,13 @@ internal class AsmGen(private val program: Program,
         loopEndLabels.pop()
     }
 
-    private fun repeatWordCountInAY(constIterations: Int?, repeatLabel: String, endLabel: String, body: AnonymousScope) {
+    private fun repeatWordCountInAY(constIterations: Int?, repeatLabel: String, endLabel: String, stmt: RepeatLoop) {
         // note: A/Y must have been loaded with the number of iterations!
         if(constIterations==0)
             return
-        // no need to explicitly test for 0 iterations as this is done in the count down logic below
+        // no need to explicitly test for 0 iterations as this is done in the countdown logic below
 
-        val counterVar = makeLabel("repeatcounter")
+        val counterVar: String = createRepeatCounterVar(DataType.UWORD, constIterations, stmt)
         out("""
                 sta  $counterVar
                 sty  $counterVar+1
@@ -1029,44 +1099,67 @@ $repeatLabel    lda  $counterVar
                 dec  $counterVar+1
 +               dec  $counterVar
 """)
-        translate(body)
+        translate(stmt.body)
         jmp(repeatLabel)
-
-        if(constIterations!=null && constIterations>=16 && zeropage.available() > 1) {
-            // allocate count var on ZP  TODO can be shared with countervars from other subroutines
-            val zpAddr = zeropage.allocate(counterVar, DataType.UWORD, body.position, errors)
-            out("$counterVar = $zpAddr  ; auto zp UWORD")
-        } else {
-            out("$counterVar    .word  0")
-        }
-
         out(endLabel)
     }
 
-    private fun repeatByteCountInA(constIterations: Int?, repeatLabel: String, endLabel: String, body: AnonymousScope) {
-        // note: A must have been loaded with the number of iterations!
+    private fun repeatByteCountInA(constIterations: Int?, repeatLabel: String, endLabel: String, stmt: RepeatLoop) {
+        // note: A must be loaded with the number of iterations!
         if(constIterations==0)
             return
+
         if(constIterations==null)
             out("  beq  $endLabel   ; skip loop if zero iters")
-        val counterVar = makeLabel("repeatcounter")
+        val counterVar = createRepeatCounterVar(DataType.UBYTE, constIterations, stmt)
         out("  sta  $counterVar")
         out(repeatLabel)
-        translate(body)
-        out("""
-             dec  $counterVar
-             bne  $repeatLabel
-             beq  $endLabel""")
+        translate(stmt.body)
+        out("  dec  $counterVar |  bne  $repeatLabel")
+        if(constIterations==null)
+            out(endLabel)
+    }
 
-        if(constIterations!=null && constIterations>=16 && zeropage.available() > 0) {
-            // allocate count var on ZP  TODO can be shared with countervars from other subroutines
-            val zpAddr = zeropage.allocate(counterVar, DataType.UBYTE, body.position, errors)
-            out("$counterVar = $zpAddr  ; auto zp UBYTE")
-        } else {
-            out("$counterVar    .byte  0")
+    private fun createRepeatCounterVar(dt: DataType, constIterations: Int?, stmt: RepeatLoop): String {
+        val asmInfo = stmt.definingSubroutine!!.asmGenInfo
+        var parent = stmt.parent
+        while(parent !is ParentSentinel) {
+            if(parent is RepeatLoop)
+                break
+            parent = parent.parent
+        }
+        val isNested = parent is RepeatLoop
+
+        if(!isNested) {
+            // we can re-use a counter var from the subroutine if it already has one for that datatype
+            val existingVar = asmInfo.extraVars.firstOrNull { it.first==dt }
+            if(existingVar!=null)
+                return existingVar.second
         }
 
-        out(endLabel)
+        val counterVar = makeLabel("repeatcounter")
+        when(dt) {
+            DataType.UBYTE -> {
+                if(constIterations!=null && constIterations>=16 && zeropage.hasByteAvailable()) {
+                    // allocate count var on ZP
+                    val zpAddr = zeropage.allocate(counterVar, DataType.UBYTE, stmt.position, errors)
+                    asmInfo.extraVars.add(Triple(DataType.UBYTE, counterVar, zpAddr))
+                } else {
+                    asmInfo.extraVars.add(Triple(DataType.UBYTE, counterVar, null))
+                }
+            }
+            DataType.UWORD -> {
+                if(constIterations!=null && constIterations>=16 && zeropage.hasWordAvailable()) {
+                    // allocate count var on ZP
+                    val zpAddr = zeropage.allocate(counterVar, DataType.UWORD, stmt.position, errors)
+                    asmInfo.extraVars.add(Triple(DataType.UWORD, counterVar, zpAddr))
+                } else {
+                    asmInfo.extraVars.add(Triple(DataType.UWORD, counterVar, null))
+                }
+            }
+            else -> throw AssemblyError("invalidt dt")
+        }
+        return counterVar
     }
 
     private fun translate(stmt: WhileLoop) {
@@ -1102,7 +1195,7 @@ $repeatLabel    lda  $counterVar
         val conditionDt = stmt.condition.inferType(program)
         if(!conditionDt.isKnown)
             throw AssemblyError("unknown condition dt")
-        if(conditionDt.typeOrElse(DataType.BYTE) in ByteDatatypes)
+        if(conditionDt.getOr(DataType.BYTE) in ByteDatatypes)
             assignExpressionToRegister(stmt.condition, RegisterOrPair.A)
         else
             assignExpressionToRegister(stmt.condition, RegisterOrPair.AY)
@@ -1117,7 +1210,7 @@ $repeatLabel    lda  $counterVar
                 choiceBlocks.add(choiceLabel to choice.statements)
                 for (cv in choice.values!!) {
                     val value = (cv as NumericLiteralValue).number.toInt()
-                    if(conditionDt.typeOrElse(DataType.BYTE) in ByteDatatypes) {
+                    if(conditionDt.getOr(DataType.BYTE) in ByteDatatypes) {
                         out("  cmp  #${value.toHex()} |  beq  $choiceLabel")
                     } else {
                         out("""
@@ -1141,7 +1234,8 @@ $repeatLabel    lda  $counterVar
     }
 
     private fun translate(stmt: Label) {
-        out("_${stmt.name}")        // underscore prefix to make sure it's a local label
+        // underscore prefix to make sure it's a local label. Is slightly problematic, see github issue #62
+        out("_${stmt.name}")
     }
 
     private fun translate(scope: AnonymousScope) {
@@ -1150,7 +1244,7 @@ $repeatLabel    lda  $counterVar
     }
 
     private fun translate(stmt: BranchStatement) {
-        if(stmt.truepart.containsNoCodeNorVars() && stmt.elsepart.containsCodeOrVars())
+        if(stmt.truepart.containsNoCodeNorVars && stmt.elsepart.containsCodeOrVars)
             throw AssemblyError("only else part contains code, shoud have been switched already")
 
         val jump = stmt.truepart.statements.first() as? Jump
@@ -1162,7 +1256,7 @@ $repeatLabel    lda  $counterVar
         } else {
             val truePartIsJustBreak = stmt.truepart.statements.firstOrNull() is Break
             val elsePartIsJustBreak = stmt.elsepart.statements.firstOrNull() is Break
-            if(stmt.elsepart.containsNoCodeNorVars()) {
+            if(stmt.elsepart.containsNoCodeNorVars) {
                 if(truePartIsJustBreak) {
                     // branch with just a break (jump out of loop)
                     val instruction = branchInstruction(stmt.condition, false)
@@ -1206,8 +1300,8 @@ $repeatLabel    lda  $counterVar
         if(stmt.value!=null && stmt.type==VarDeclType.VAR && stmt.datatype in NumericDatatypes) {
             // generate an assignment statement to (re)initialize the variable's value.
             // if the vardecl is not in a subroutine however, we have to initialize it globally.
-            if(stmt.definingSubroutine()==null) {
-                val block = stmt.definingBlock()
+            if(stmt.definingSubroutine ==null) {
+                val block = stmt.definingBlock
                 var inits = blockLevelVarInits[block]
                 if(inits==null) {
                     inits = mutableSetOf()
@@ -1223,23 +1317,32 @@ $repeatLabel    lda  $counterVar
         }
     }
 
+    /**
+     * TODO: %asminclude and %asmbinary should be done earlier than code gen (-> put content into AST) ... (describe why?)
+     */
     private fun translate(stmt: Directive) {
         when(stmt.directive) {
             "%asminclude" -> {
-                val sourcecode = loadAsmIncludeFile(stmt.args[0].str!!, stmt.definingModule().source)
-                val scopeprefix = stmt.args[1].str ?: ""
-                if(scopeprefix.isNotBlank())
-                    out("$scopeprefix\t.proc")
-                assemblyLines.add(sourcecode.trimEnd().trimStart('\n'))
-                if(scopeprefix.isNotBlank())
-                    out("  .pend\n")
+                // TODO: handle %asminclude with SourceCode
+                val includedName = stmt.args[0].str!!
+                val sourcePath = Path(stmt.definingModule.source!!.pathString()) // FIXME: %asminclude inside non-library, non-filesystem module
+                loadAsmIncludeFile(includedName, sourcePath).fold(
+                    success = { assemblyLines.add(it.trimEnd().trimStart('\n')) },
+                    failure = { errors.err(it.toString(), stmt.position) }
+                )
             }
             "%asmbinary" -> {
+                val includedName = stmt.args[0].str!!
                 val offset = if(stmt.args.size>1) ", ${stmt.args[1].int}" else ""
                 val length = if(stmt.args.size>2) ", ${stmt.args[2].int}" else ""
-                val includedSourcePath = stmt.definingModule().source.resolveSibling(stmt.args[0].str)
-                val relPath = Paths.get("").relativize(includedSourcePath)
-                out("  .binary \"./$relPath\" $offset $length")
+                val sourcePath = Path(stmt.definingModule.source!!.pathString()) // FIXME: %asmbinary inside non-library, non-filesystem module
+                val includedPath = sourcePath.resolveSibling(includedName)
+                val pathForAssembler = outputDir // #54: 64tass needs the path *relative to the .asm file*
+                    .absolute() // avoid IllegalArgumentExc due to non-absolute path .relativize(absolute path)
+                    .relativize(includedPath)
+                    .normalize() // avoid assembler warnings (-Wportable; only some, not all)
+                    .toString().replace('\\', '/')
+                out("  .binary \"$pathForAssembler\" $offset $length")
             }
             "%breakpoint" -> {
                 val label = "_prog8_breakpoint_${breakpointLabels.size+1}"
@@ -1258,23 +1361,16 @@ $label              nop""")
         val label = jump.generatedLabel
         val addr = jump.address
         return when {
-            ident!=null -> {
-                val target = ident.targetStatement(program)
-                val asmName = asmSymbolName(ident)
-                if(target is Label)
-                    "_$asmName"  // prefix with underscore to jump to local label
-                else
-                    asmName
-            }
+            ident!=null -> asmSymbolName(ident)
             label!=null -> label
             addr!=null -> addr.toHex()
             else -> "????"
         }
     }
 
-    private fun translate(ret: Return) {
+    internal fun translate(ret: Return, withRts: Boolean=true) {
         ret.value?.let { returnvalue ->
-            val sub = ret.definingSubroutine()!!
+            val sub = ret.definingSubroutine!!
             val returnType = sub.returntypes.single()
             val returnReg = sub.asmReturnvaluesRegisters.single()
             if(returnReg.registerOrPair==null)
@@ -1291,7 +1387,9 @@ $label              nop""")
                 }
             }
         }
-        out("  rts")
+
+        if(withRts)
+            out("  rts")
     }
 
     private fun translate(asm: InlineAssembly) {
@@ -1371,7 +1469,7 @@ $label              nop""")
                 if(constIdx!=null && constIdx.number.toInt()>=0 && constIdx.number.toInt()<=255) {
                     return Pair(pointerOffsetExpr.left, NumericLiteralValue(DataType.UBYTE, constIdx.number, constIdx.position))
                 }
-                // could be that the index was type casted into uword, check that
+                // could be that the index was typecasted into uword, check that
                 val rightTc = pointerOffsetExpr.right as? TypecastExpression
                 if(rightTc!=null && rightTc.expression.inferType(program).istype(DataType.UBYTE))
                     return Pair(pointerOffsetExpr.left, rightTc.expression)
@@ -1405,38 +1503,48 @@ $label              nop""")
             val ptrAndIndex = pointerViaIndexRegisterPossible(expr)
             if(ptrAndIndex!=null) {
                 val pointervar = ptrAndIndex.first as? IdentifierReference
-                if(write) {
-                    if(pointervar!=null && isZpVar(pointervar)) {
-                        val saveA = evalBytevalueWillClobberA(ptrAndIndex.second)
-                        if(saveA)
-                            out("  pha")
+                when(pointervar?.targetStatement(program)) {
+                    is Label -> {
                         assignExpressionToRegister(ptrAndIndex.second, RegisterOrPair.Y)
-                        if(saveA)
-                            out("  pla")
-                        out("  sta  (${asmSymbolName(pointervar)}),y")
-                    } else {
-                        // copy the pointer var to zp first
-                        val saveA = evalBytevalueWillClobberA(ptrAndIndex.first) || evalBytevalueWillClobberA(ptrAndIndex.second)
-                        if(saveA)
-                            out("  pha")
-                        assignExpressionToVariable(ptrAndIndex.first, asmVariableName("P8ZP_SCRATCH_W2"), DataType.UWORD, null)
-                        assignExpressionToRegister(ptrAndIndex.second, RegisterOrPair.Y)
-                        if(saveA)
-                            out("  pla")
-                        out("  sta  (P8ZP_SCRATCH_W2),y")
+                        out("  lda  ${asmSymbolName(pointervar)},y")
+                        return true
                     }
-                } else {
-                    if(pointervar!=null && isZpVar(pointervar)) {
-                        assignExpressionToRegister(ptrAndIndex.second, RegisterOrPair.Y)
-                        out("  lda  (${asmSymbolName(pointervar)}),y")
-                    } else {
-                        // copy the pointer var to zp first
-                        assignExpressionToVariable(ptrAndIndex.first, asmVariableName("P8ZP_SCRATCH_W2"), DataType.UWORD, null)
-                        assignExpressionToRegister(ptrAndIndex.second, RegisterOrPair.Y)
-                        out("  lda  (P8ZP_SCRATCH_W2),y")
+                    is VarDecl, null -> {
+                        if(write) {
+                            if(pointervar!=null && isZpVar(pointervar)) {
+                                val saveA = evalBytevalueWillClobberA(ptrAndIndex.second)
+                                if(saveA)
+                                    out("  pha")
+                                assignExpressionToRegister(ptrAndIndex.second, RegisterOrPair.Y)
+                                if(saveA)
+                                    out("  pla")
+                                out("  sta  (${asmSymbolName(pointervar)}),y")
+                            } else {
+                                // copy the pointer var to zp first
+                                val saveA = evalBytevalueWillClobberA(ptrAndIndex.first) || evalBytevalueWillClobberA(ptrAndIndex.second)
+                                if(saveA)
+                                    out("  pha")
+                                assignExpressionToVariable(ptrAndIndex.first, "P8ZP_SCRATCH_W2", DataType.UWORD, null)
+                                assignExpressionToRegister(ptrAndIndex.second, RegisterOrPair.Y)
+                                if(saveA)
+                                    out("  pla")
+                                out("  sta  (P8ZP_SCRATCH_W2),y")
+                            }
+                        } else {
+                            if(pointervar!=null && isZpVar(pointervar)) {
+                                assignExpressionToRegister(ptrAndIndex.second, RegisterOrPair.Y)
+                                out("  lda  (${asmSymbolName(pointervar)}),y")
+                            } else {
+                                // copy the pointer var to zp first
+                                assignExpressionToVariable(ptrAndIndex.first, "P8ZP_SCRATCH_W2", DataType.UWORD, null)
+                                assignExpressionToRegister(ptrAndIndex.second, RegisterOrPair.Y)
+                                out("  lda  (P8ZP_SCRATCH_W2),y")
+                            }
+                        }
+                        return true
                     }
+                    else -> throw AssemblyError("invalid pointervar")
                 }
-                return true
             }
         }
         return false

compiler/src/prog8/compiler/target/cpu6502/codegen/AsmOptimizer.kt

@@ -74,7 +74,7 @@ private fun getLinesBy(lines: MutableList<String>, windowSize: Int) =
         lines.withIndex().filter { it.value.isNotBlank() && !it.value.trimStart().startsWith(';') }.windowed(windowSize, partialWindows = false)
 
 private fun optimizeCmpSequence(linesByFour: List<List<IndexedValue<String>>>): List<Modification> {
-    // the when statement (on bytes) generates a sequence of:
+    // when statement (on bytes) generates a sequence of:
     //	 lda  $ce01,x
     //	 cmp  #$20
     //	 beq  check_prog8_s72choice_32

compiler/src/prog8/compiler/target/cpu6502/codegen/BuiltinFunctionsAsmGen.kt

@@ -13,6 +13,7 @@ import prog8.ast.toHex
 import prog8.compiler.AssemblyError
 import prog8.compiler.functions.FSignature
 import prog8.compiler.target.CpuType
+import prog8.compiler.target.Cx16Target
 import prog8.compiler.target.cpu6502.codegen.assignment.*
 import prog8.compiler.target.subroutineFloatEvalResultVar2
 
@@ -33,7 +34,7 @@ internal class BuiltinFunctionsAsmGen(private val program: Program, private val
         if(discardResult && resultToStack)
             throw AssemblyError("cannot both discard the result AND put it onto stack")
 
-        val sscope = (fcall as Node).definingSubroutine()
+        val sscope = (fcall as Node).definingSubroutine
 
         when (func.name) {
             "msb" -> funcMsb(fcall, resultToStack, resultRegister)
@@ -51,7 +52,7 @@ internal class BuiltinFunctionsAsmGen(private val program: Program, private val
             "ln", "log2", "sqrt", "rad",
             "deg", "round", "floor", "ceil",
             "rndf" -> funcVariousFloatFuncs(fcall, func, resultToStack, resultRegister, sscope)
-            "fastrnd8", "rnd", "rndw" -> funcRnd(func, resultToStack, resultRegister, sscope)
+            "rnd", "rndw" -> funcRnd(func, resultToStack, resultRegister, sscope)
             "sqrt16" -> funcSqrt16(fcall, func, resultToStack, resultRegister, sscope)
             "rol" -> funcRol(fcall)
             "rol2" -> funcRol2(fcall)
@@ -65,15 +66,119 @@ internal class BuiltinFunctionsAsmGen(private val program: Program, private val
             "pokew" -> funcPokeW(fcall)
             "poke" -> throw AssemblyError("poke() should have been replaced by @()")
             "cmp" -> funcCmp(fcall)
+            "callfar" -> funcCallFar(fcall)
+            "callrom" -> funcCallRom(fcall)
             else -> throw AssemblyError("missing asmgen for builtin func ${func.name}")
         }
     }
 
+    private fun funcCallFar(fcall: IFunctionCall) {
+        if(asmgen.options.compTarget !is Cx16Target)
+            throw AssemblyError("callfar only works on cx16 target at this time")
+
+        val bank = fcall.args[0].constValue(program)?.number?.toInt()
+        val address = fcall.args[1].constValue(program)?.number?.toInt()
+        if(bank==null || address==null)
+            throw AssemblyError("callfar (jsrfar) requires constant arguments")
+
+        if(address !in 0xa000..0xbfff)
+            throw AssemblyError("callfar done on address outside of cx16 banked ram")
+        if(bank==0)
+            throw AssemblyError("callfar done on bank 0 which is reserved for the kernal")
+
+        val argAddrArg = fcall.args[2]
+        if(argAddrArg.constValue(program)?.number == 0) {
+            asmgen.out("""
+                jsr  cx16.jsrfar
+                .word  ${address.toHex()}
+                .byte  ${bank.toHex()}""")
+        } else {
+            when(argAddrArg) {
+                is AddressOf -> {
+                    if(argAddrArg.identifier.targetVarDecl(program)?.datatype != DataType.UBYTE)
+                        throw AssemblyError("callfar done with 'arg' pointer to variable that's not UBYTE")
+                    asmgen.out("""
+                        lda  ${asmgen.asmVariableName(argAddrArg.identifier)}
+                        jsr  cx16.jsrfar
+                        .word  ${address.toHex()}
+                        .byte  ${bank.toHex()}
+                        sta  ${asmgen.asmVariableName(argAddrArg.identifier)}""")
+                }
+                is NumericLiteralValue -> {
+                    asmgen.out("""
+                        lda  ${argAddrArg.number.toHex()}
+                        jsr  cx16.jsrfar
+                        .word  ${address.toHex()}
+                        .byte  ${bank.toHex()}
+                        sta  ${argAddrArg.number.toHex()}""")
+                }
+                else -> throw AssemblyError("callfar only accepts pointer-of a (ubyte) variable or constant memory address for the 'arg' parameter")
+            }
+        }
+    }
+
+    private fun funcCallRom(fcall: IFunctionCall) {
+        if(asmgen.options.compTarget !is Cx16Target)
+            throw AssemblyError("callrom only works on cx16 target at this time")
+
+        val bank = fcall.args[0].constValue(program)?.number?.toInt()
+        val address = fcall.args[1].constValue(program)?.number?.toInt()
+        if(bank==null || address==null)
+            throw AssemblyError("callrom requires constant arguments")
+
+        if(address !in 0xc000..0xffff)
+            throw AssemblyError("callrom done on address outside of cx16 banked rom")
+        if(bank>=32)
+            throw AssemblyError("callrom bank must be <32")
+
+        val argAddrArg = fcall.args[2]
+        if(argAddrArg.constValue(program)?.number == 0) {
+            asmgen.out("""
+                lda  $01
+                pha
+                lda  #${bank}
+                sta  $01
+                jsr  ${address.toHex()}
+                pla
+                sta  $01""")
+        } else {
+            when(argAddrArg) {
+                is AddressOf -> {
+                    if(argAddrArg.identifier.targetVarDecl(program)?.datatype != DataType.UBYTE)
+                        throw AssemblyError("callrom done with 'arg' pointer to variable that's not UBYTE")
+                    asmgen.out("""
+                        lda  $01
+                        pha
+                        lda  #${bank}
+                        sta  $01
+                        lda  ${asmgen.asmVariableName(argAddrArg.identifier)}                
+                        jsr  ${address.toHex()}
+                        sta  ${asmgen.asmVariableName(argAddrArg.identifier)}
+                        pla
+                        sta  $01""")
+                }
+                is NumericLiteralValue -> {
+                    asmgen.out("""
+                        lda  $01
+                        pha
+                        lda  #${bank}
+                        sta  $01
+                        lda  ${argAddrArg.number.toHex()}
+                        jsr  ${address.toHex()}
+                        sta  ${argAddrArg.number.toHex()}
+                        pla
+                        sta  $01""")
+                }
+                else -> throw AssemblyError("callrom only accepts pointer-of a (ubyte) variable or constant memory address for the 'arg' parameter")
+            }
+        }
+    }
+
     private fun funcCmp(fcall: IFunctionCall) {
         val arg1 = fcall.args[0]
         val arg2 = fcall.args[1]
-        val dt1 = arg1.inferType(program).typeOrElse(DataType.STRUCT)
-        val dt2 = arg2.inferType(program).typeOrElse(DataType.STRUCT)
+        val dt1 = arg1.inferType(program).getOr(DataType.UNDEFINED)
+        val dt2 = arg2.inferType(program).getOr(DataType.UNDEFINED)
         if(dt1 in ByteDatatypes) {
             if(dt2 in ByteDatatypes) {
                 when (arg2) {
@@ -90,13 +195,13 @@ internal class BuiltinFunctionsAsmGen(private val program: Program, private val
                             asmgen.assignExpressionToRegister(arg1, RegisterOrPair.A)
                             asmgen.out("  cmp  ${arg2.addressExpression.constValue(program)!!.number.toHex()}")
                         } else {
-                            asmgen.assignExpressionToVariable(arg2, "P8ZP_SCRATCH_B1", DataType.UBYTE, (fcall as Node).definingSubroutine())
+                            asmgen.assignExpressionToVariable(arg2, "P8ZP_SCRATCH_B1", DataType.UBYTE, (fcall as Node).definingSubroutine)
                             asmgen.assignExpressionToRegister(arg1, RegisterOrPair.A)
                             asmgen.out("  cmp  P8ZP_SCRATCH_B1")
                         }
                     }
                     else -> {
-                        asmgen.assignExpressionToVariable(arg2, "P8ZP_SCRATCH_B1", DataType.UBYTE, (fcall as Node).definingSubroutine())
+                        asmgen.assignExpressionToVariable(arg2, "P8ZP_SCRATCH_B1", DataType.UBYTE, (fcall as Node).definingSubroutine)
                         asmgen.assignExpressionToRegister(arg1, RegisterOrPair.A)
                         asmgen.out("  cmp  P8ZP_SCRATCH_B1")
                     }
@@ -124,7 +229,7 @@ internal class BuiltinFunctionsAsmGen(private val program: Program, private val
 +""")
                     }
                     else -> {
-                        asmgen.assignExpressionToVariable(arg2, "P8ZP_SCRATCH_W1", DataType.UWORD, (fcall as Node).definingSubroutine())
+                        asmgen.assignExpressionToVariable(arg2, "P8ZP_SCRATCH_W1", DataType.UWORD, (fcall as Node).definingSubroutine)
                         asmgen.assignExpressionToRegister(arg1, RegisterOrPair.AY)
                         asmgen.out("""
                             cpy  P8ZP_SCRATCH_W1+1
@@ -263,7 +368,7 @@ internal class BuiltinFunctionsAsmGen(private val program: Program, private val
     private fun funcRor2(fcall: IFunctionCall) {
         val what = fcall.args.single()
         val dt = what.inferType(program)
-        when (dt.typeOrElse(DataType.STRUCT)) {
+        when (dt.getOr(DataType.UNDEFINED)) {
             DataType.UBYTE -> {
                 when (what) {
                     is ArrayIndexedExpression -> {
@@ -306,7 +411,7 @@ internal class BuiltinFunctionsAsmGen(private val program: Program, private val
     private fun funcRor(fcall: IFunctionCall) {
         val what = fcall.args.single()
         val dt = what.inferType(program)
-        when (dt.typeOrElse(DataType.STRUCT)) {
+        when (dt.getOr(DataType.UNDEFINED)) {
             DataType.UBYTE -> {
                 when (what) {
                     is ArrayIndexedExpression -> {
@@ -321,7 +426,7 @@ internal class BuiltinFunctionsAsmGen(private val program: Program, private val
                             val ptrAndIndex = asmgen.pointerViaIndexRegisterPossible(what.addressExpression)
                             if(ptrAndIndex!=null) {
                                 asmgen.assignExpressionToRegister(ptrAndIndex.second, RegisterOrPair.X)
-                                asmgen.saveRegisterLocal(CpuRegister.X, (fcall as FunctionCallStatement).definingSubroutine()!!)
+                                asmgen.saveRegisterLocal(CpuRegister.X, (fcall as FunctionCallStatement).definingSubroutine!!)
                                 asmgen.assignExpressionToRegister(ptrAndIndex.first, RegisterOrPair.AY)
                                 asmgen.restoreRegisterLocal(CpuRegister.X)
                                 asmgen.out("""
@@ -364,7 +469,7 @@ internal class BuiltinFunctionsAsmGen(private val program: Program, private val
     private fun funcRol2(fcall: IFunctionCall) {
         val what = fcall.args.single()
         val dt = what.inferType(program)
-        when (dt.typeOrElse(DataType.STRUCT)) {
+        when (dt.getOr(DataType.UNDEFINED)) {
             DataType.UBYTE -> {
                 when (what) {
                     is ArrayIndexedExpression -> {
@@ -407,7 +512,7 @@ internal class BuiltinFunctionsAsmGen(private val program: Program, private val
     private fun funcRol(fcall: IFunctionCall) {
         val what = fcall.args.single()
         val dt = what.inferType(program)
-        when (dt.typeOrElse(DataType.STRUCT)) {
+        when (dt.getOr(DataType.UNDEFINED)) {
             DataType.UBYTE -> {
                 when (what) {
                     is ArrayIndexedExpression -> {
@@ -422,7 +527,7 @@ internal class BuiltinFunctionsAsmGen(private val program: Program, private val
                             val ptrAndIndex = asmgen.pointerViaIndexRegisterPossible(what.addressExpression)
                             if(ptrAndIndex!=null) {
                                 asmgen.assignExpressionToRegister(ptrAndIndex.second, RegisterOrPair.X)
-                                asmgen.saveRegisterLocal(CpuRegister.X, (fcall as FunctionCallStatement).definingSubroutine()!!)
+                                asmgen.saveRegisterLocal(CpuRegister.X, (fcall as FunctionCallStatement).definingSubroutine!!)
                                 asmgen.assignExpressionToRegister(ptrAndIndex.first, RegisterOrPair.AY)
                                 asmgen.restoreRegisterLocal(CpuRegister.X)
                                 asmgen.out("""
@@ -481,7 +586,7 @@ internal class BuiltinFunctionsAsmGen(private val program: Program, private val
         translateArguments(fcall.args, func, scope)
         val dt = fcall.args.single().inferType(program)
         if(resultToStack) {
-            when (dt.typeOrElse(DataType.STRUCT)) {
+            when (dt.getOr(DataType.UNDEFINED)) {
                 DataType.UBYTE -> asmgen.out("  jsr  prog8_lib.func_sign_ub_stack")
                 DataType.BYTE -> asmgen.out("  jsr  prog8_lib.func_sign_b_stack")
                 DataType.UWORD -> asmgen.out("  jsr  prog8_lib.func_sign_uw_stack")
@@ -490,7 +595,7 @@ internal class BuiltinFunctionsAsmGen(private val program: Program, private val
                 else -> throw AssemblyError("weird type $dt")
             }
         } else {
-            when (dt.typeOrElse(DataType.STRUCT)) {
+            when (dt.getOr(DataType.UNDEFINED)) {
                 DataType.UBYTE -> asmgen.out("  jsr  prog8_lib.func_sign_ub_into_A")
                 DataType.BYTE -> asmgen.out("  jsr  prog8_lib.func_sign_b_into_A")
                 DataType.UWORD -> asmgen.out("  jsr  prog8_lib.func_sign_uw_into_A")
@@ -506,14 +611,14 @@ internal class BuiltinFunctionsAsmGen(private val program: Program, private val
         outputAddressAndLenghtOfArray(fcall.args[0])
         val dt = fcall.args.single().inferType(program)
         if(resultToStack) {
-            when (dt.typeOrElse(DataType.STRUCT)) {
+            when (dt.getOr(DataType.UNDEFINED)) {
                 DataType.ARRAY_B, DataType.ARRAY_UB, DataType.STR -> asmgen.out("  jsr  prog8_lib.func_${function.name}_b_stack")
                 DataType.ARRAY_UW, DataType.ARRAY_W -> asmgen.out("  jsr  prog8_lib.func_${function.name}_w_stack")
                 DataType.ARRAY_F -> asmgen.out("  jsr  floats.func_${function.name}_f_stack")
                 else -> throw AssemblyError("weird type $dt")
             }
         } else {
-            when (dt.typeOrElse(DataType.STRUCT)) {
+            when (dt.getOr(DataType.UNDEFINED)) {
                 DataType.ARRAY_B, DataType.ARRAY_UB, DataType.STR -> asmgen.out("  jsr  prog8_lib.func_${function.name}_b_into_A")
                 DataType.ARRAY_UW, DataType.ARRAY_W -> asmgen.out("  jsr  prog8_lib.func_${function.name}_w_into_A")
                 DataType.ARRAY_F -> asmgen.out("  jsr  floats.func_${function.name}_f_into_A")
@@ -527,7 +632,7 @@ internal class BuiltinFunctionsAsmGen(private val program: Program, private val
         outputAddressAndLenghtOfArray(fcall.args[0])
         val dt = fcall.args.single().inferType(program)
         if(resultToStack) {
-            when (dt.typeOrElse(DataType.STRUCT)) {
+            when (dt.getOr(DataType.UNDEFINED)) {
                 DataType.ARRAY_UB, DataType.STR -> asmgen.out("  jsr  prog8_lib.func_${function.name}_ub_stack")
                 DataType.ARRAY_B -> asmgen.out("  jsr  prog8_lib.func_${function.name}_b_stack")
                 DataType.ARRAY_UW -> asmgen.out("  jsr  prog8_lib.func_${function.name}_uw_stack")
@@ -536,7 +641,7 @@ internal class BuiltinFunctionsAsmGen(private val program: Program, private val
                 else -> throw AssemblyError("weird type $dt")
             }
         } else {
-            when (dt.typeOrElse(DataType.STRUCT)) {
+            when (dt.getOr(DataType.UNDEFINED)) {
                 DataType.ARRAY_UB, DataType.STR -> {
                     asmgen.out("  jsr  prog8_lib.func_${function.name}_ub_into_A")
                     assignAsmGen.assignRegisterByte(AsmAssignTarget.fromRegisters(resultRegister ?: RegisterOrPair.A, scope, program, asmgen), CpuRegister.A)
@@ -566,7 +671,7 @@ internal class BuiltinFunctionsAsmGen(private val program: Program, private val
         outputAddressAndLenghtOfArray(fcall.args[0])
         val dt = fcall.args.single().inferType(program)
         if(resultToStack) {
-            when (dt.typeOrElse(DataType.STRUCT)) {
+            when (dt.getOr(DataType.UNDEFINED)) {
                 DataType.ARRAY_UB, DataType.STR -> asmgen.out("  jsr  prog8_lib.func_sum_ub_stack")
                 DataType.ARRAY_B -> asmgen.out("  jsr  prog8_lib.func_sum_b_stack")
                 DataType.ARRAY_UW -> asmgen.out("  jsr  prog8_lib.func_sum_uw_stack")
@@ -575,7 +680,7 @@ internal class BuiltinFunctionsAsmGen(private val program: Program, private val
                 else -> throw AssemblyError("weird type $dt")
             }
         } else {
-            when (dt.typeOrElse(DataType.STRUCT)) {
+            when (dt.getOr(DataType.UNDEFINED)) {
                 DataType.ARRAY_UB, DataType.STR -> {
                     asmgen.out("  jsr  prog8_lib.func_sum_ub_into_AY")
                     assignAsmGen.assignRegisterpairWord(AsmAssignTarget.fromRegisters(resultRegister ?: RegisterOrPair.AY, scope, program, asmgen), RegisterOrPair.AY)
@@ -645,7 +750,6 @@ internal class BuiltinFunctionsAsmGen(private val program: Program, private val
 
         // optimized simple case: swap two memory locations
         if(first is DirectMemoryRead && second is DirectMemoryRead) {
-            // TODO optimize swap of two memread values with index, using the same pointer expression/variable, like swap(@(ptr+1), @(ptr+2))
             val addr1 = (first.addressExpression as? NumericLiteralValue)?.number?.toHex()
             val addr2 = (second.addressExpression as? NumericLiteralValue)?.number?.toHex()
             val name1 = if(first.addressExpression is IdentifierReference) asmgen.asmVariableName(first.addressExpression as IdentifierReference) else null
@@ -668,6 +772,50 @@ internal class BuiltinFunctionsAsmGen(private val program: Program, private val
                     asmgen.out("  ldy  $name1 |  lda  $name2 |  sta  $name1 |  sty  $name2")
                     return
                 }
+                addr1==null && addr2==null && name1==null && name2==null -> {
+                    val firstExpr = first.addressExpression as? BinaryExpression
+                    val secondExpr = second.addressExpression as? BinaryExpression
+                    if(firstExpr!=null && secondExpr!=null) {
+                        val pointerVariable = firstExpr.left as? IdentifierReference
+                        val firstOffset = firstExpr.right
+                        val secondOffset = secondExpr.right
+                        if(pointerVariable != null
+                            && pointerVariable isSameAs secondExpr.left
+                            && firstExpr.operator == "+" && secondExpr.operator == "+"
+                            && (firstOffset is NumericLiteralValue || firstOffset is IdentifierReference || firstOffset is TypecastExpression)
+                            && (secondOffset is NumericLiteralValue || secondOffset is IdentifierReference || secondOffset is TypecastExpression)
+                        ) {
+                            val pointerVar = firstExpr.left as IdentifierReference
+                            if(firstOffset is NumericLiteralValue && secondOffset is NumericLiteralValue) {
+                                if(firstOffset!=secondOffset) {
+                                    swapArrayValues(
+                                        DataType.UBYTE,
+                                        asmgen.asmVariableName(pointerVariable), firstOffset,
+                                        asmgen.asmVariableName(pointerVariable), secondOffset
+                                    )
+                                    return
+                                }
+                            } else if(firstOffset is TypecastExpression && secondOffset is TypecastExpression) {
+                                if(firstOffset.type in WordDatatypes && secondOffset.type in WordDatatypes) {
+                                    val firstOffsetVar = firstOffset.expression as? IdentifierReference
+                                    val secondOffsetVar = secondOffset.expression as? IdentifierReference
+                                    if(firstOffsetVar!=null && secondOffsetVar!=null) {
+                                        if(firstOffsetVar!=secondOffsetVar) {
+                                            swapArrayValues(
+                                                DataType.UBYTE,
+                                                asmgen.asmVariableName(pointerVariable), firstOffsetVar,
+                                                asmgen.asmVariableName(pointerVariable), secondOffsetVar
+                                            )
+                                            return
+                                        }
+                                    }
+                                }
+                            } else if(firstOffset is IdentifierReference || secondOffset is IdentifierReference) {
+                                throw AssemblyError("expected a typecast-to-word for index variable at ${firstOffset.position} and/or ${secondOffset.position}")
+                            }
+                        }
+                    }
+                }
             }
         }
 
@@ -677,7 +825,7 @@ internal class BuiltinFunctionsAsmGen(private val program: Program, private val
             val elementIDt = first.inferType(program)
             if(!elementIDt.isKnown)
                 throw AssemblyError("unknown dt")
-            val elementDt = elementIDt.typeOrElse(DataType.STRUCT)
+            val elementDt = elementIDt.getOr(DataType.UNDEFINED)
 
             val firstNum = first.indexer.indexExpr as? NumericLiteralValue
             val firstVar = first.indexer.indexExpr as? IdentifierReference
@@ -703,15 +851,14 @@ internal class BuiltinFunctionsAsmGen(private val program: Program, private val
 
         fun targetFromExpr(expr: Expression, datatype: DataType): AsmAssignTarget {
             return when (expr) {
-                is IdentifierReference -> AsmAssignTarget(TargetStorageKind.VARIABLE, program, asmgen, datatype, expr.definingSubroutine(), variableAsmName = asmgen.asmVariableName(expr))
-                is ArrayIndexedExpression -> AsmAssignTarget(TargetStorageKind.ARRAY, program, asmgen, datatype, expr.definingSubroutine(), array = expr)
-                is DirectMemoryRead -> AsmAssignTarget(TargetStorageKind.MEMORY, program, asmgen, datatype, expr.definingSubroutine(), memory = DirectMemoryWrite(expr.addressExpression, expr.position))
+                is IdentifierReference -> AsmAssignTarget(TargetStorageKind.VARIABLE, program, asmgen, datatype, expr.definingSubroutine, variableAsmName = asmgen.asmVariableName(expr))
+                is ArrayIndexedExpression -> AsmAssignTarget(TargetStorageKind.ARRAY, program, asmgen, datatype, expr.definingSubroutine, array = expr)
+                is DirectMemoryRead -> AsmAssignTarget(TargetStorageKind.MEMORY, program, asmgen, datatype, expr.definingSubroutine, memory = DirectMemoryWrite(expr.addressExpression, expr.position))
                 else -> throw AssemblyError("invalid expression object $expr")
             }
         }
 
-        val datatype = first.inferType(program).typeOrElse(DataType.STRUCT)
-        when(datatype) {
+        when(val datatype: DataType = first.inferType(program).getOr(DataType.UNDEFINED)) {
             in ByteDatatypes, in WordDatatypes -> {
                 asmgen.assignExpressionToVariable(first, "P8ZP_SCRATCH_W1", datatype, null)
                 asmgen.assignExpressionToVariable(second, "P8ZP_SCRATCH_W2", datatype, null)
@@ -783,7 +930,7 @@ internal class BuiltinFunctionsAsmGen(private val program: Program, private val
                     sta  P8ZP_SCRATCH_W2
                     lda  #>(${arrayVarName2}+$index2)
                     sta  P8ZP_SCRATCH_W2+1
-                    jsr  floats.swap_floats
+                    jsr  floats.func_swap_f
                 """)
             }
             else -> throw AssemblyError("invalid aray elt type")
@@ -856,7 +1003,7 @@ internal class BuiltinFunctionsAsmGen(private val program: Program, private val
                     sta  P8ZP_SCRATCH_W2
                     bcc  +
                     inc  P8ZP_SCRATCH_W2+1
-+                   jsr  floats.swap_floats                                   
++                   jsr  floats.func_swap_f                                   
                 """)
             }
             else -> throw AssemblyError("invalid aray elt type")
@@ -914,7 +1061,7 @@ internal class BuiltinFunctionsAsmGen(private val program: Program, private val
                     sta  P8ZP_SCRATCH_W1
                     bcc  +
                     inc  P8ZP_SCRATCH_W1+1
-+                   jsr  floats.swap_floats
++                   jsr  floats.func_swap_f
                 """)
             }
             else -> throw AssemblyError("invalid aray elt type")
@@ -972,7 +1119,7 @@ internal class BuiltinFunctionsAsmGen(private val program: Program, private val
                     sta  P8ZP_SCRATCH_W2
                     lda  #>(${arrayVarName2}+$index2)
                     sta  P8ZP_SCRATCH_W2+1
-                    jsr  floats.swap_floats
+                    jsr  floats.func_swap_f
                 """)
             }
             else -> throw AssemblyError("invalid aray elt type")
@@ -981,7 +1128,7 @@ internal class BuiltinFunctionsAsmGen(private val program: Program, private val
 
     private fun funcAbs(fcall: IFunctionCall, func: FSignature, resultToStack: Boolean, resultRegister: RegisterOrPair?, scope: Subroutine?) {
         translateArguments(fcall.args, func, scope)
-        val dt = fcall.args.single().inferType(program).typeOrElse(DataType.STRUCT)
+        val dt = fcall.args.single().inferType(program).getOr(DataType.UNDEFINED)
         if(resultToStack) {
             when (dt) {
                 in ByteDatatypes -> asmgen.out("  jsr  prog8_lib.abs_b_stack")
@@ -1010,14 +1157,6 @@ internal class BuiltinFunctionsAsmGen(private val program: Program, private val
 
     private fun funcRnd(func: FSignature, resultToStack: Boolean, resultRegister: RegisterOrPair?, scope: Subroutine?) {
         when(func.name) {
-            "fastrnd8" -> {
-                if(resultToStack)
-                    asmgen.out("  jsr  prog8_lib.func_fastrnd8_stack")
-                else {
-                    asmgen.out("  jsr  math.fast_randbyte")
-                    assignAsmGen.assignRegisterByte(AsmAssignTarget.fromRegisters(resultRegister ?: RegisterOrPair.A, scope, program, asmgen), CpuRegister.A)
-                }
-            }
             "rnd" -> {
                 if(resultToStack)
                     asmgen.out("  jsr  prog8_lib.func_rnd_stack")
@@ -1050,7 +1189,7 @@ internal class BuiltinFunctionsAsmGen(private val program: Program, private val
                 val varname = asmgen.asmVariableName(addrExpr)
                 if(asmgen.isZpVar(addrExpr)) {
                     // pointervar is already in the zero page, no need to copy
-                    asmgen.saveRegisterLocal(CpuRegister.X, (fcall as Node).definingSubroutine()!!)
+                    asmgen.saveRegisterLocal(CpuRegister.X, (fcall as Node).definingSubroutine!!)
                     asmgen.assignExpressionToRegister(fcall.args[1], RegisterOrPair.AX)
                     if (asmgen.isTargetCpu(CpuType.CPU65c02)) {
                         asmgen.out("""
@@ -1072,18 +1211,21 @@ internal class BuiltinFunctionsAsmGen(private val program: Program, private val
             }
             is BinaryExpression -> {
                 if(addrExpr.operator=="+" && addrExpr.left is IdentifierReference && addrExpr.right is NumericLiteralValue) {
-                    asmgen.saveRegisterLocal(CpuRegister.X, (fcall as Node).definingSubroutine()!!)
-                    asmgen.assignExpressionToRegister(fcall.args[1], RegisterOrPair.AX)
                     val varname = asmgen.asmVariableName(addrExpr.left as IdentifierReference)
-                    val index = (addrExpr.right as NumericLiteralValue).number.toHex()
-                    asmgen.out("""
-                        ldy  #$index
-                        sta  ($varname),y
-                        txa
-                        iny
-                        sta  ($varname),y""")
-                    asmgen.restoreRegisterLocal(CpuRegister.X)
-                    return
+                    if(asmgen.isZpVar(addrExpr.left as IdentifierReference)) {
+                        // pointervar is already in the zero page, no need to copy
+                        asmgen.saveRegisterLocal(CpuRegister.X, (fcall as Node).definingSubroutine!!)
+                        asmgen.assignExpressionToRegister(fcall.args[1], RegisterOrPair.AX)
+                        val index = (addrExpr.right as NumericLiteralValue).number.toHex()
+                        asmgen.out("""
+                            ldy  #$index
+                            sta  ($varname),y
+                            txa
+                            iny
+                            sta  ($varname),y""")
+                        asmgen.restoreRegisterLocal(CpuRegister.X)
+                        return
+                    }
                 }
             }
         }
@@ -1127,15 +1269,21 @@ internal class BuiltinFunctionsAsmGen(private val program: Program, private val
             is BinaryExpression -> {
                 if(addrExpr.operator=="+" && addrExpr.left is IdentifierReference && addrExpr.right is NumericLiteralValue) {
                     val varname = asmgen.asmVariableName(addrExpr.left as IdentifierReference)
-                    val index = (addrExpr.right as NumericLiteralValue).number.toHex()
-                    asmgen.out("""
-                        ldy  #$index
-                        lda  ($varname),y
-                        pha
-                        iny
-                        lda  ($varname),y
-                        tay
-                        pla""")
+                    if(asmgen.isZpVar(addrExpr.left as IdentifierReference)) {
+                        // pointervar is already in the zero page, no need to copy
+                        val index = (addrExpr.right as NumericLiteralValue).number.toHex()
+                        asmgen.out("""
+                            ldy  #$index
+                            lda  ($varname),y
+                            pha
+                            iny
+                            lda  ($varname),y
+                            tay
+                            pla""")
+                    }  else {
+                        asmgen.assignExpressionToRegister(fcall.args[0], RegisterOrPair.AY)
+                        asmgen.out("  jsr  prog8_lib.func_peekw")
+                    }
                 } else {
                     asmgen.assignExpressionToRegister(fcall.args[0], RegisterOrPair.AY)
                     asmgen.out("  jsr  prog8_lib.func_peekw")
@@ -1154,7 +1302,10 @@ internal class BuiltinFunctionsAsmGen(private val program: Program, private val
                 RegisterOrPair.AY -> {}
                 RegisterOrPair.AX -> asmgen.out("  sty  P8ZP_SCRATCH_REG |  ldx  P8ZP_SCRATCH_REG")
                 RegisterOrPair.XY -> asmgen.out("  tax")
-                in Cx16VirtualRegisters -> asmgen.out("  sta  cx16.${resultRegister.toString().toLowerCase()} |  sty  cx16.${resultRegister.toString().toLowerCase()}+1")
+                in Cx16VirtualRegisters -> asmgen.out(
+                    "  sta  cx16.${
+                        resultRegister.toString().lowercase()
+                    } |  sty  cx16.${resultRegister.toString().lowercase()}+1")
                 else -> throw AssemblyError("invalid reg")
             }
         }
@@ -1204,9 +1355,9 @@ internal class BuiltinFunctionsAsmGen(private val program: Program, private val
                 }
                 in Cx16VirtualRegisters -> {
                     asmgen.assignExpressionToRegister(fcall.args[1], RegisterOrPair.A)      // lsb
-                    asmgen.out("  sta  cx16.${reg.toString().toLowerCase()}")
+                    asmgen.out("  sta  cx16.${reg.toString().lowercase()}")
                     asmgen.assignExpressionToRegister(fcall.args[0], RegisterOrPair.A)      // msb
-                    asmgen.out("  sta  cx16.${reg.toString().toLowerCase()}+1")
+                    asmgen.out("  sta  cx16.${reg.toString().lowercase()}+1")
                 }
                 else -> throw AssemblyError("invalid mkword target reg")
             }
@@ -1215,7 +1366,7 @@ internal class BuiltinFunctionsAsmGen(private val program: Program, private val
 
     private fun funcMsb(fcall: IFunctionCall, resultToStack: Boolean, resultRegister: RegisterOrPair?) {
         val arg = fcall.args.single()
-        if (arg.inferType(program).typeOrElse(DataType.STRUCT) !in WordDatatypes)
+        if (!arg.inferType(program).isWords)
             throw AssemblyError("msb required word argument")
         if (arg is NumericLiteralValue)
             throw AssemblyError("msb(const) should have been const-folded away")
@@ -1259,7 +1410,7 @@ internal class BuiltinFunctionsAsmGen(private val program: Program, private val
 
     private fun funcLsb(fcall: IFunctionCall, resultToStack: Boolean, resultRegister: RegisterOrPair?) {
         val arg = fcall.args.single()
-        if (arg.inferType(program).typeOrElse(DataType.STRUCT) !in WordDatatypes)
+        if (!arg.inferType(program).isWords)
             throw AssemblyError("lsb required word argument")
         if (arg is NumericLiteralValue)
             throw AssemblyError("lsb(const) should have been const-folded away")
@@ -1323,7 +1474,7 @@ internal class BuiltinFunctionsAsmGen(private val program: Program, private val
     }
 
     private fun translateArguments(args: MutableList<Expression>, signature: FSignature, scope: Subroutine?) {
-        val callConv = signature.callConvention(args.map { it.inferType(program).typeOrElse(DataType.STRUCT) })
+        val callConv = signature.callConvention(args.map { it.inferType(program).getOr(DataType.UNDEFINED) })
 
         fun getSourceForFloat(value: Expression): AsmAssignSource {
             return when (value) {

compiler/src/prog8/compiler/target/cpu6502/codegen/ExpressionsAsmGen.kt

@@ -57,37 +57,26 @@ internal class ExpressionsAsmGen(private val program: Program, private val asmge
         val idt = left.inferType(program)
         if(!idt.isKnown)
             throw AssemblyError("unknown dt")
-        val dt = idt.typeOrElse(DataType.STRUCT)
+        val dt = idt.getOr(DataType.UNDEFINED)
         when (operator) {
             "==" -> {
                 // if the left operand is an expression, and the right is 0, we can just evaluate that expression,
                 // and use the result value directly to determine the boolean result. Shortcut only for integers.
                 if(rightConstVal?.number?.toDouble() == 0.0) {
-                    when(left) {
-                        is PrefixExpression,
-                        is BinaryExpression,
-                        is ArrayIndexedExpression,
-                        is TypecastExpression,
-                        is AddressOf,
-                        is RangeExpr,
-                        is FunctionCall -> {
-                            if(dt in ByteDatatypes) {
-                                asmgen.assignExpressionToRegister(left, RegisterOrPair.A)
-                                if(left is FunctionCall)
-                                    asmgen.out("  cmp  #0")
-                                asmgen.out("  bne  $jumpIfFalseLabel")
-                                return
-                            }
-                            else if(dt in WordDatatypes) {
-                                asmgen.assignExpressionToRegister(left, RegisterOrPair.AY)
-                                asmgen.out("""
-                                    sty  P8ZP_SCRATCH_B1
-                                    ora  P8ZP_SCRATCH_B1
-                                    bne  $jumpIfFalseLabel""")
-                                return
-                            }
-                        }
-                        else -> {}
+                    if(dt in ByteDatatypes) {
+                        asmgen.assignExpressionToRegister(left, RegisterOrPair.A)
+                        if(left is FunctionCall && !left.isSimple)
+                            asmgen.out("  cmp  #0")
+                        asmgen.out("  bne  $jumpIfFalseLabel")
+                        return
+                    }
+                    else if(dt in WordDatatypes) {
+                        asmgen.assignExpressionToRegister(left, RegisterOrPair.AY)
+                        asmgen.out("""
+                            sty  P8ZP_SCRATCH_B1
+                            ora  P8ZP_SCRATCH_B1
+                            bne  $jumpIfFalseLabel""")
+                        return
                     }
                 }
 
@@ -103,31 +92,20 @@ internal class ExpressionsAsmGen(private val program: Program, private val asmge
                 // if the left operand is an expression, and the right is 0, we can just evaluate that expression,
                 // and use the result value directly to determine the boolean result. Shortcut only for integers.
                 if(rightConstVal?.number?.toDouble() == 0.0) {
-                    when(left) {
-                        is PrefixExpression,
-                        is BinaryExpression,
-                        is ArrayIndexedExpression,
-                        is TypecastExpression,
-                        is AddressOf,
-                        is RangeExpr,
-                        is FunctionCall -> {
-                            if(dt in ByteDatatypes) {
-                                asmgen.assignExpressionToRegister(left, RegisterOrPair.A)
-                                if(left is FunctionCall)
-                                    asmgen.out("  cmp  #0")
-                                asmgen.out("  beq  $jumpIfFalseLabel")
-                                return
-                            }
-                            else if(dt in WordDatatypes) {
-                                asmgen.assignExpressionToRegister(left, RegisterOrPair.AY)
-                                asmgen.out("""
-                                    sty  P8ZP_SCRATCH_B1
-                                    ora  P8ZP_SCRATCH_B1
-                                    beq  $jumpIfFalseLabel""")
-                                return
-                            }
-                        }
-                        else -> {}
+                    if(dt in ByteDatatypes) {
+                        asmgen.assignExpressionToRegister(left, RegisterOrPair.A)
+                        if(left is FunctionCall && !left.isSimple)
+                            asmgen.out("  cmp  #0")
+                        asmgen.out("  beq  $jumpIfFalseLabel")
+                        return
+                    }
+                    else if(dt in WordDatatypes) {
+                        asmgen.assignExpressionToRegister(left, RegisterOrPair.AY)
+                        asmgen.out("""
+                            sty  P8ZP_SCRATCH_B1
+                            ora  P8ZP_SCRATCH_B1
+                            beq  $jumpIfFalseLabel""")
+                        return
                     }
                 }
 
@@ -219,7 +197,7 @@ internal class ExpressionsAsmGen(private val program: Program, private val asmge
                 jsr  floats.vars_less_f
                 beq  $jumpIfFalseLabel""")
         } else {
-            val subroutine = left.definingSubroutine()!!
+            val subroutine = left.definingSubroutine!!
             subroutine.asmGenInfo.usedFloatEvalResultVar1 = true
             asmgen.assignExpressionToVariable(right, subroutineFloatEvalResultVar1, DataType.FLOAT, subroutine)
             asmgen.assignExpressionToRegister(left, RegisterOrPair.FAC1)
@@ -264,7 +242,7 @@ internal class ExpressionsAsmGen(private val program: Program, private val asmge
                 jsr  floats.vars_lesseq_f
                 beq  $jumpIfFalseLabel""")
         } else {
-            val subroutine = left.definingSubroutine()!!
+            val subroutine = left.definingSubroutine!!
             subroutine.asmGenInfo.usedFloatEvalResultVar1 = true
             asmgen.assignExpressionToVariable(right, subroutineFloatEvalResultVar1, DataType.FLOAT, subroutine)
             asmgen.assignExpressionToRegister(left, RegisterOrPair.FAC1)
@@ -309,7 +287,7 @@ internal class ExpressionsAsmGen(private val program: Program, private val asmge
                 jsr  floats.vars_less_f
                 beq  $jumpIfFalseLabel""")
         } else {
-            val subroutine = left.definingSubroutine()!!
+            val subroutine = left.definingSubroutine!!
             subroutine.asmGenInfo.usedFloatEvalResultVar1 = true
             asmgen.assignExpressionToVariable(right, subroutineFloatEvalResultVar1, DataType.FLOAT, subroutine)
             asmgen.assignExpressionToRegister(left, RegisterOrPair.FAC1)
@@ -354,7 +332,7 @@ internal class ExpressionsAsmGen(private val program: Program, private val asmge
                 jsr  floats.vars_lesseq_f
                 beq  $jumpIfFalseLabel""")
         } else {
-            val subroutine = left.definingSubroutine()!!
+            val subroutine = left.definingSubroutine!!
             subroutine.asmGenInfo.usedFloatEvalResultVar1 = true
             asmgen.assignExpressionToVariable(right, subroutineFloatEvalResultVar1, DataType.FLOAT, subroutine)
             asmgen.assignExpressionToRegister(left, RegisterOrPair.FAC1)
@@ -397,7 +375,7 @@ internal class ExpressionsAsmGen(private val program: Program, private val asmge
             }
         }
 
-        if(byteJumpForSimpleRightOperands(left, right, ::code))
+        if(byteJumpForSimpleRightOperand(left, right, ::code))
             return
 
         asmgen.assignExpressionToVariable(right, "P8ZP_SCRATCH_B1", DataType.UBYTE, null)
@@ -432,7 +410,7 @@ internal class ExpressionsAsmGen(private val program: Program, private val asmge
             }
         }
 
-        if(byteJumpForSimpleRightOperands(left, right, ::code))
+        if(byteJumpForSimpleRightOperand(left, right, ::code))
             return
 
         asmgen.assignExpressionToVariable(right, "P8ZP_SCRATCH_B1", DataType.UBYTE, null)
@@ -440,7 +418,36 @@ internal class ExpressionsAsmGen(private val program: Program, private val asmge
         return code("P8ZP_SCRATCH_B1")
     }
 
-    private fun byteJumpForSimpleRightOperands(left: Expression, right: Expression, code: (String)->Unit): Boolean {
+    private fun wordJumpForSimpleLeftOperand(left: Expression, right: Expression, code: (String, String)->Unit): Boolean {
+        when (left) {
+            is NumericLiteralValue -> {
+                asmgen.assignExpressionToRegister(right, RegisterOrPair.AY)
+                val number = left.number.toHex()
+                code("#>$number", "#<$number")
+                return true
+            }
+            is AddressOf -> {
+                asmgen.assignExpressionToRegister(right, RegisterOrPair.AY)
+                val name = asmgen.asmSymbolName(left.identifier)
+                code("#>$name", "#<$name")
+                return true
+            }
+            is IdentifierReference -> {
+                asmgen.assignExpressionToRegister(right, RegisterOrPair.AY)
+                val varname = asmgen.asmVariableName(left)
+                code("$varname+1", varname)
+                return true
+            }
+            else -> return false
+        }
+    }
+
+    private fun byteJumpForSimpleRightOperand(left: Expression, right: Expression, code: (String)->Unit): Boolean {
+        if(right is NumericLiteralValue) {
+            asmgen.assignExpressionToRegister(left, RegisterOrPair.A)
+            code("#${right.number.toHex()}")
+            return true
+        }
         if(right is IdentifierReference) {
             asmgen.assignExpressionToRegister(left, RegisterOrPair.A)
             code(asmgen.asmVariableName(right))
@@ -460,6 +467,30 @@ internal class ExpressionsAsmGen(private val program: Program, private val asmge
         return false
     }
 
+    private fun wordJumpForSimpleRightOperands(left: Expression, right: Expression, code: (String, String)->Unit): Boolean {
+        when (right) {
+            is NumericLiteralValue -> {
+                asmgen.assignExpressionToRegister(left, RegisterOrPair.AY)
+                val number = right.number.toHex()
+                code("#>$number", "#<$number")
+                return true
+            }
+            is AddressOf -> {
+                asmgen.assignExpressionToRegister(left, RegisterOrPair.AY)
+                val name = asmgen.asmSymbolName(right.identifier)
+                code("#>$name", "#<$name")
+                return true
+            }
+            is IdentifierReference -> {
+                asmgen.assignExpressionToRegister(left, RegisterOrPair.AY)
+                val varname = asmgen.asmVariableName(right)
+                code("$varname+1", varname)
+                return true
+            }
+            else -> return false
+        }
+    }
+
     private fun translateUwordLessJump(left: Expression, right: Expression, leftConstVal: NumericLiteralValue?, rightConstVal: NumericLiteralValue?, jumpIfFalseLabel: String) {
 
         fun code(msbCpyOperand: String, lsbCmpOperand: String) {
@@ -489,11 +520,8 @@ internal class ExpressionsAsmGen(private val program: Program, private val asmge
             }
         }
 
-        if(right is IdentifierReference) {
-            asmgen.assignExpressionToRegister(left, RegisterOrPair.AY)
-            val varname = asmgen.asmVariableName(right)
-            return code("$varname+1", varname)
-        }
+        if(wordJumpForSimpleRightOperands(left, right, ::code))
+            return
 
         asmgen.assignExpressionToVariable(right, "P8ZP_SCRATCH_W2", DataType.UWORD, null)
         asmgen.assignExpressionToRegister(left, RegisterOrPair.AY)
@@ -531,11 +559,8 @@ internal class ExpressionsAsmGen(private val program: Program, private val asmge
             }
         }
 
-        if(right is IdentifierReference) {
-            asmgen.assignExpressionToRegister(left, RegisterOrPair.AY)
-            val varname = asmgen.asmVariableName(right)
-            return code("$varname+1", varname)
-        }
+        if(wordJumpForSimpleRightOperands(left, right, ::code))
+            return
 
         asmgen.assignExpressionToVariable(right, "P8ZP_SCRATCH_W2", DataType.UWORD, null)
         asmgen.assignExpressionToRegister(left, RegisterOrPair.AY)
@@ -574,7 +599,7 @@ internal class ExpressionsAsmGen(private val program: Program, private val asmge
             }
         }
 
-        if(byteJumpForSimpleRightOperands(left, right, ::code))
+        if(byteJumpForSimpleRightOperand(left, right, ::code))
             return
 
         asmgen.assignExpressionToVariable(right, "P8ZP_SCRATCH_B1", DataType.UBYTE, null)
@@ -611,7 +636,7 @@ internal class ExpressionsAsmGen(private val program: Program, private val asmge
             }
         }
 
-        if(byteJumpForSimpleRightOperands(left, right, ::code))
+        if(byteJumpForSimpleRightOperand(left, right, ::code))
             return
 
         asmgen.assignExpressionToVariable(right, "P8ZP_SCRATCH_B1", DataType.UBYTE, null)
@@ -654,11 +679,8 @@ internal class ExpressionsAsmGen(private val program: Program, private val asmge
             }
         }
 
-        if(right is IdentifierReference) {
-            asmgen.assignExpressionToRegister(left, RegisterOrPair.AY)
-            val varname = asmgen.asmVariableName(right)
-            return code("$varname+1", varname)
-        }
+        if(wordJumpForSimpleRightOperands(left, right, ::code))
+            return
 
         asmgen.assignExpressionToVariable(right, "P8ZP_SCRATCH_W2", DataType.UWORD, null)
         asmgen.assignExpressionToRegister(left, RegisterOrPair.AY)
@@ -667,11 +689,11 @@ internal class ExpressionsAsmGen(private val program: Program, private val asmge
 
     private fun translateWordGreaterJump(left: Expression, right: Expression, leftConstVal: NumericLiteralValue?, rightConstVal: NumericLiteralValue?, jumpIfFalseLabel: String) {
 
-        fun code(leftName: String) {
+        fun code(msbCmpOperand: String, lsbCmpOperand: String) {
             asmgen.out("""
-                cmp  $leftName
+                cmp  $lsbCmpOperand
                 tya
-                sbc  $leftName+1
+                sbc  $msbCmpOperand
                 bvc  +
                 eor  #$80
 +               bpl  $jumpIfFalseLabel""")
@@ -686,7 +708,8 @@ internal class ExpressionsAsmGen(private val program: Program, private val asmge
                 if (left is IdentifierReference) {
                     return if(rightConstVal.number.toInt()!=0) {
                         asmgen.assignExpressionToRegister(right, RegisterOrPair.AY)
-                        code(asmgen.asmVariableName(left))
+                        val varname = asmgen.asmVariableName(left)
+                        code("$varname+1", varname)
                     }
                     else {
                         val name = asmgen.asmVariableName(left)
@@ -700,10 +723,8 @@ internal class ExpressionsAsmGen(private val program: Program, private val asmge
             }
         }
 
-        if(left is IdentifierReference) {
-            asmgen.assignExpressionToRegister(right, RegisterOrPair.AY)
-            return code(asmgen.asmVariableName(left))
-        }
+        if(wordJumpForSimpleLeftOperand(left, right, ::code))
+            return
 
         asmgen.assignExpressionToVariable(left, "P8ZP_SCRATCH_W2", DataType.UWORD, null)
         asmgen.assignExpressionToRegister(right, RegisterOrPair.AY)
@@ -743,7 +764,7 @@ internal class ExpressionsAsmGen(private val program: Program, private val asmge
             }
         }
 
-        if(byteJumpForSimpleRightOperands(left, right, ::code))
+        if(byteJumpForSimpleRightOperand(left, right, ::code))
             return
 
         asmgen.assignExpressionToVariable(right, "P8ZP_SCRATCH_B1", DataType.UBYTE, null)
@@ -780,7 +801,7 @@ internal class ExpressionsAsmGen(private val program: Program, private val asmge
             }
         }
 
-        if(byteJumpForSimpleRightOperands(left, right, ::code))
+        if(byteJumpForSimpleRightOperand(left, right, ::code))
             return
 
         asmgen.assignExpressionToVariable(right, "P8ZP_SCRATCH_B1", DataType.UBYTE, null)
@@ -825,11 +846,8 @@ internal class ExpressionsAsmGen(private val program: Program, private val asmge
             }
         }
 
-        if(right is IdentifierReference) {
-            asmgen.assignExpressionToRegister(left, RegisterOrPair.AY)
-            val varname = asmgen.asmVariableName(right)
-            return code("$varname+1", varname)
-        }
+        if(wordJumpForSimpleRightOperands(left, right, ::code))
+            return
 
         asmgen.assignExpressionToVariable(right, "P8ZP_SCRATCH_W2", DataType.UWORD, null)
         asmgen.assignExpressionToRegister(left, RegisterOrPair.AY)
@@ -913,7 +931,7 @@ internal class ExpressionsAsmGen(private val program: Program, private val asmge
             }
         }
 
-        if(byteJumpForSimpleRightOperands(left, right, ::code))
+        if(byteJumpForSimpleRightOperand(left, right, ::code))
             return
 
         asmgen.assignExpressionToVariable(right, "P8ZP_SCRATCH_B1", DataType.UBYTE, null)
@@ -947,7 +965,7 @@ internal class ExpressionsAsmGen(private val program: Program, private val asmge
             }
         }
 
-        if(byteJumpForSimpleRightOperands(left, right, ::code))
+        if(byteJumpForSimpleRightOperand(left, right, ::code))
             return
 
         asmgen.assignExpressionToVariable(right, "P8ZP_SCRATCH_B1", DataType.UBYTE, null)
@@ -982,11 +1000,8 @@ internal class ExpressionsAsmGen(private val program: Program, private val asmge
             }
         }
 
-        if(right is IdentifierReference) {
-            asmgen.assignExpressionToRegister(left, RegisterOrPair.AY)
-            val varname = asmgen.asmVariableName(right)
-            return code("$varname+1", varname)
-        }
+        if(wordJumpForSimpleRightOperands(left, right, ::code))
+            return
 
         asmgen.assignExpressionToVariable(left, "P8ZP_SCRATCH_W2", DataType.UWORD, null)
         asmgen.assignExpressionToRegister(right, RegisterOrPair.AY)
@@ -1024,11 +1039,8 @@ internal class ExpressionsAsmGen(private val program: Program, private val asmge
             }
         }
 
-        if(right is IdentifierReference) {
-            asmgen.assignExpressionToRegister(left, RegisterOrPair.AY)
-            val varname = asmgen.asmVariableName(right)
-            return code("$varname+1", varname)
-        }
+        if(wordJumpForSimpleRightOperands(left, right, ::code))
+            return
 
         asmgen.assignExpressionToVariable(right, "P8ZP_SCRATCH_W2", DataType.UWORD, null)
         asmgen.assignExpressionToRegister(left, RegisterOrPair.AY)
@@ -1063,7 +1075,7 @@ internal class ExpressionsAsmGen(private val program: Program, private val asmge
             }
         }
 
-        if(byteJumpForSimpleRightOperands(left, right, ::code))
+        if(byteJumpForSimpleRightOperand(left, right, ::code))
             return
 
         asmgen.assignExpressionToVariable(right, "P8ZP_SCRATCH_B1", DataType.UBYTE, null)
@@ -1100,7 +1112,7 @@ internal class ExpressionsAsmGen(private val program: Program, private val asmge
             }
         }
 
-        if(byteJumpForSimpleRightOperands(left, right, ::code))
+        if(byteJumpForSimpleRightOperand(left, right, ::code))
             return
 
         asmgen.assignExpressionToVariable(right, "P8ZP_SCRATCH_B1", DataType.UBYTE, null)
@@ -1136,24 +1148,47 @@ internal class ExpressionsAsmGen(private val program: Program, private val asmge
             }
         }
 
-        if(right is IdentifierReference) {
-            asmgen.assignExpressionToRegister(left, RegisterOrPair.AY)
-            asmgen.out("""
-                cmp  ${asmgen.asmVariableName(right)}
-                bne  $jumpIfFalseLabel
-                cpy  ${asmgen.asmVariableName(right)}+1
-                bne  $jumpIfFalseLabel
-                """)
-            return
+        when (right) {
+            is NumericLiteralValue -> {
+                asmgen.assignExpressionToRegister(left, RegisterOrPair.AY)
+                val number = right.number.toHex()
+                asmgen.out("""
+                    cmp  #<$number
+                    bne  $jumpIfFalseLabel
+                    cpy  #>$number
+                    bne  $jumpIfFalseLabel
+                    """)
+            }
+            is IdentifierReference -> {
+                asmgen.assignExpressionToRegister(left, RegisterOrPair.AY)
+                asmgen.out("""
+                    cmp  ${asmgen.asmVariableName(right)}
+                    bne  $jumpIfFalseLabel
+                    cpy  ${asmgen.asmVariableName(right)}+1
+                    bne  $jumpIfFalseLabel
+                    """)
+            }
+            is AddressOf -> {
+                asmgen.assignExpressionToRegister(left, RegisterOrPair.AY)
+                val name = asmgen.asmSymbolName(right.identifier)
+                asmgen.out("""
+                    cmp  #<$name
+                    bne  $jumpIfFalseLabel
+                    cpy  #>$name
+                    bne  $jumpIfFalseLabel
+                    """)
+            }
+            else -> {
+                asmgen.assignExpressionToVariable(right, "P8ZP_SCRATCH_W2", DataType.UWORD, null)
+                asmgen.assignExpressionToRegister(left, RegisterOrPair.AY)
+                asmgen.out("""
+                    cmp  P8ZP_SCRATCH_W2
+                    bne  $jumpIfFalseLabel
+                    cpy  P8ZP_SCRATCH_W2+1
+                    bne  $jumpIfFalseLabel""")
+            }
         }
 
-        asmgen.assignExpressionToVariable(right, "P8ZP_SCRATCH_W2", DataType.UWORD, null)
-        asmgen.assignExpressionToRegister(left, RegisterOrPair.AY)
-        asmgen.out("""
-            cmp  P8ZP_SCRATCH_W2
-            bne  $jumpIfFalseLabel
-            cpy  P8ZP_SCRATCH_W2+1
-            bne  $jumpIfFalseLabel""")
     }
 
     private fun translateWordNotEqualsJump(left: Expression, right: Expression, leftConstVal: NumericLiteralValue?, rightConstVal: NumericLiteralValue?, jumpIfFalseLabel: String) {
@@ -1187,25 +1222,49 @@ internal class ExpressionsAsmGen(private val program: Program, private val asmge
             }
         }
 
-        if(right is IdentifierReference) {
-            asmgen.assignExpressionToRegister(left, RegisterOrPair.AY)
-            asmgen.out("""
-                cmp  ${asmgen.asmVariableName(right)}
-                bne  +
-                cpy  ${asmgen.asmVariableName(right)}+1
-                beq  $jumpIfFalseLabel
+        when (right) {
+            is NumericLiteralValue -> {
+                asmgen.assignExpressionToRegister(left, RegisterOrPair.AY)
+                val number = right.number.toHex()
+                asmgen.out("""
+                    cmp  #<$number
+                    bne  +
+                    cpy  #>$number
+                    beq  $jumpIfFalseLabel
 +""")
-            return
+            }
+            is IdentifierReference -> {
+                asmgen.assignExpressionToRegister(left, RegisterOrPair.AY)
+                asmgen.out("""
+                    cmp  ${asmgen.asmVariableName(right)}
+                    bne  +
+                    cpy  ${asmgen.asmVariableName(right)}+1
+                    beq  $jumpIfFalseLabel
++""")
+            }
+            is AddressOf -> {
+                asmgen.assignExpressionToRegister(left, RegisterOrPair.AY)
+                val name = asmgen.asmSymbolName(right.identifier)
+                asmgen.out("""
+                    cmp  #<$name
+                    bne  +
+                    cpy  #>$name
+                    beq  $jumpIfFalseLabel
++""")
+            }
+            else -> {
+                asmgen.assignExpressionToVariable(right, "P8ZP_SCRATCH_W2", DataType.UWORD, null)
+                asmgen.assignExpressionToRegister(left, RegisterOrPair.AY)
+                asmgen.out("""
+                    cmp  P8ZP_SCRATCH_W2
+                    bne  +
+                    cpy  P8ZP_SCRATCH_W2+1
+                    beq  $jumpIfFalseLabel
++"""
+                )
+            }
         }
 
-        asmgen.assignExpressionToVariable(right, "P8ZP_SCRATCH_W2", DataType.UWORD, null)
-        asmgen.assignExpressionToRegister(left, RegisterOrPair.AY)
-        asmgen.out("""
-            cmp  P8ZP_SCRATCH_W2
-            bne  +
-            cpy  P8ZP_SCRATCH_W2+1
-            beq  $jumpIfFalseLabel
-+""")
     }
 
     private fun translateFloatEqualsJump(left: Expression, right: Expression, leftConstVal: NumericLiteralValue?, rightConstVal: NumericLiteralValue?, jumpIfFalseLabel: String) {
@@ -1280,7 +1339,7 @@ internal class ExpressionsAsmGen(private val program: Program, private val asmge
                 jsr  floats.vars_equal_f
                 beq  $jumpIfFalseLabel""")
         } else {
-            val subroutine = left.definingSubroutine()!!
+            val subroutine = left.definingSubroutine!!
             subroutine.asmGenInfo.usedFloatEvalResultVar1 = true
             asmgen.assignExpressionToVariable(right, subroutineFloatEvalResultVar1, DataType.FLOAT, subroutine)
             asmgen.assignExpressionToRegister(left, RegisterOrPair.FAC1)
@@ -1365,7 +1424,7 @@ internal class ExpressionsAsmGen(private val program: Program, private val asmge
                 jsr  floats.vars_equal_f
                 bne  $jumpIfFalseLabel""")
         } else {
-            val subroutine = left.definingSubroutine()!!
+            val subroutine = left.definingSubroutine!!
             subroutine.asmGenInfo.usedFloatEvalResultVar1 = true
             asmgen.assignExpressionToVariable(right, subroutineFloatEvalResultVar1, DataType.FLOAT, subroutine)
             asmgen.assignExpressionToRegister(left, RegisterOrPair.FAC1)
@@ -1514,10 +1573,11 @@ internal class ExpressionsAsmGen(private val program: Program, private val asmge
                         RegisterOrPair.R13,
                         RegisterOrPair.R14,
                         RegisterOrPair.R15 -> {
-                            asmgen.out("""
-                                lda  cx16.${reg.registerOrPair.toString().toLowerCase()}
+                            asmgen.out(
+                                """
+                                lda  cx16.${reg.registerOrPair.toString().lowercase()}
                                 sta  P8ESTACK_LO,x
-                                lda  cx16.${reg.registerOrPair.toString().toLowerCase()}+1
+                                lda  cx16.${reg.registerOrPair.toString().lowercase()}+1
                                 sta  P8ESTACK_HI,x
                                 dex
                             """)
@@ -1566,7 +1626,7 @@ internal class ExpressionsAsmGen(private val program: Program, private val asmge
 
     private fun translateExpression(typecast: TypecastExpression) {
         translateExpression(typecast.expression)
-        when(typecast.expression.inferType(program).typeOrElse(DataType.STRUCT)) {
+        when(typecast.expression.inferType(program).getOr(DataType.UNDEFINED)) {
             DataType.UBYTE -> {
                 when(typecast.type) {
                     DataType.UBYTE, DataType.BYTE -> {}
@@ -1636,7 +1696,7 @@ internal class ExpressionsAsmGen(private val program: Program, private val asmge
     internal fun translateDirectMemReadExpression(expr: DirectMemoryRead, pushResultOnEstack: Boolean) {
 
         fun assignViaExprEval() {
-            asmgen.assignExpressionToVariable(expr.addressExpression, asmgen.asmVariableName("P8ZP_SCRATCH_W2"), DataType.UWORD, null)
+            asmgen.assignExpressionToVariable(expr.addressExpression, "P8ZP_SCRATCH_W2", DataType.UWORD, null)
             if (asmgen.isTargetCpu(CpuType.CPU65c02)) {
                 if (pushResultOnEstack) {
                     asmgen.out("  lda  (P8ZP_SCRATCH_W2) |  dex |  sta  P8ESTACK_LO+1,x")
@@ -1697,7 +1757,7 @@ internal class ExpressionsAsmGen(private val program: Program, private val asmge
 
     private fun translateExpression(expr: IdentifierReference) {
         val varname = asmgen.asmVariableName(expr)
-        when(expr.inferType(program).typeOrElse(DataType.STRUCT)) {
+        when(expr.inferType(program).getOr(DataType.UNDEFINED)) {
             DataType.UBYTE, DataType.BYTE -> {
                 asmgen.out("  lda  $varname  |  sta  P8ESTACK_LO,x  |  dex")
             }
@@ -1721,8 +1781,8 @@ internal class ExpressionsAsmGen(private val program: Program, private val asmge
         if(!leftIDt.isKnown || !rightIDt.isKnown)
             throw AssemblyError("can't infer type of both expression operands")
 
-        val leftDt = leftIDt.typeOrElse(DataType.STRUCT)
-        val rightDt = rightIDt.typeOrElse(DataType.STRUCT)
+        val leftDt = leftIDt.getOr(DataType.UNDEFINED)
+        val rightDt = rightIDt.getOr(DataType.UNDEFINED)
         // see if we can apply some optimized routines
         // TODO avoid using evaluation on stack everywhere
         when(expr.operator) {
@@ -2048,7 +2108,7 @@ internal class ExpressionsAsmGen(private val program: Program, private val asmge
         val itype = expr.inferType(program)
         if(!itype.isKnown)
             throw AssemblyError("unknown dt")
-        val type = itype.typeOrElse(DataType.STRUCT)
+        val type = itype.getOr(DataType.UNDEFINED)
         when(expr.operator) {
             "+" -> {}
             "-" -> {
@@ -2086,7 +2146,7 @@ internal class ExpressionsAsmGen(private val program: Program, private val asmge
         val elementIDt = arrayExpr.inferType(program)
         if(!elementIDt.isKnown)
             throw AssemblyError("unknown dt")
-        val elementDt = elementIDt.typeOrElse(DataType.STRUCT)
+        val elementDt = elementIDt.getOr(DataType.UNDEFINED)
         val arrayVarName = asmgen.asmVariableName(arrayExpr.arrayvar)
         val constIndexNum = arrayExpr.indexer.constIndex()
         if(constIndexNum!=null) {

compiler/src/prog8/compiler/target/cpu6502/codegen/ForLoopsAsmGen.kt

@@ -1,7 +1,7 @@
 package prog8.compiler.target.cpu6502.codegen
 
 import prog8.ast.Program
-import prog8.ast.base.ArrayElementTypes
+import prog8.ast.base.ArrayToElementTypes
 import prog8.ast.base.DataType
 import prog8.ast.base.RegisterOrPair
 import prog8.ast.expressions.IdentifierReference
@@ -9,6 +9,7 @@ import prog8.ast.expressions.RangeExpr
 import prog8.ast.statements.ForLoop
 import prog8.ast.toHex
 import prog8.compiler.AssemblyError
+import prog8.compiler.astprocessing.toConstantIntegerRange
 import kotlin.math.absoluteValue
 
 internal class ForLoopsAsmGen(private val program: Program, private val asmgen: AsmGen) {
@@ -19,15 +20,15 @@ internal class ForLoopsAsmGen(private val program: Program, private val asmgen:
             throw AssemblyError("unknown dt")
         when(stmt.iterable) {
             is RangeExpr -> {
-                val range = (stmt.iterable as RangeExpr).toConstantIntegerRange()
+                val range = (stmt.iterable as RangeExpr).toConstantIntegerRange(asmgen.options.compTarget)
                 if(range==null) {
-                    translateForOverNonconstRange(stmt, iterableDt.typeOrElse(DataType.STRUCT), stmt.iterable as RangeExpr)
+                    translateForOverNonconstRange(stmt, iterableDt.getOr(DataType.UNDEFINED), stmt.iterable as RangeExpr)
                 } else {
-                    translateForOverConstRange(stmt, iterableDt.typeOrElse(DataType.STRUCT), range)
+                    translateForOverConstRange(stmt, iterableDt.getOr(DataType.UNDEFINED), range)
                 }
             }
             is IdentifierReference -> {
-                translateForOverIterableVar(stmt, iterableDt.typeOrElse(DataType.STRUCT), stmt.iterable as IdentifierReference)
+                translateForOverIterableVar(stmt, iterableDt.getOr(DataType.UNDEFINED), stmt.iterable as IdentifierReference)
             }
             else -> throw AssemblyError("can't iterate over ${stmt.iterable.javaClass} - should have been replaced by a variable")
         }
@@ -40,6 +41,13 @@ internal class ForLoopsAsmGen(private val program: Program, private val asmgen:
         val modifiedLabel2 = asmgen.makeLabel("for_modifiedb")
         asmgen.loopEndLabels.push(endLabel)
         val stepsize=range.step.constValue(program)!!.number.toInt()
+
+        if(stepsize < -1) {
+            val limit = range.to.constValue(program)?.number?.toDouble()
+            if(limit==0.0)
+                throw AssemblyError("for unsigned loop variable it's not possible to count down with step != -1 from a non-const value to exactly zero due to value wrapping")
+        }
+
         when(iterableDt) {
             DataType.ARRAY_B, DataType.ARRAY_UB -> {
                 if (stepsize==1 || stepsize==-1) {
@@ -49,8 +57,8 @@ internal class ForLoopsAsmGen(private val program: Program, private val asmgen:
                     val incdec = if(stepsize==1) "inc" else "dec"
                     // loop over byte range via loopvar
                     val varname = asmgen.asmVariableName(stmt.loopVar)
-                    asmgen.assignExpressionToVariable(range.from, varname, ArrayElementTypes.getValue(iterableDt), null)
-                    asmgen.assignExpressionToVariable(range.to, "$modifiedLabel+1", ArrayElementTypes.getValue(iterableDt), null)
+                    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("""
@@ -67,8 +75,8 @@ $modifiedLabel          cmp  #0         ; modified
 
                     // loop over byte range via loopvar
                     val varname = asmgen.asmVariableName(stmt.loopVar)
-                    asmgen.assignExpressionToVariable(range.from, varname, ArrayElementTypes.getValue(iterableDt), null)
-                    asmgen.assignExpressionToVariable(range.to, "$modifiedLabel+1", ArrayElementTypes.getValue(iterableDt), null)
+                    asmgen.assignExpressionToVariable(range.from, varname, ArrayToElementTypes.getValue(iterableDt), null)
+                    asmgen.assignExpressionToVariable(range.to, "$modifiedLabel+1", ArrayToElementTypes.getValue(iterableDt), null)
                     asmgen.out(loopLabel)
                     asmgen.translate(stmt.body)
                     if(stepsize>0) {
@@ -281,7 +289,7 @@ $loopLabel          sty  $indexVar
                         bne  $loopLabel
                         beq  $endLabel""")
                 }
-                if(length>=16 && asmgen.zeropage.available() > 0) {
+                if(length>=16 && asmgen.zeropage.hasByteAvailable()) {
                     // allocate index var on ZP
                     val zpAddr = asmgen.zeropage.allocate(indexVar, DataType.UBYTE, stmt.position, asmgen.errors)
                     asmgen.out("""$indexVar = $zpAddr  ; auto zp UBYTE""")
@@ -320,7 +328,7 @@ $loopLabel          sty  $indexVar
                         bne  $loopLabel
                         beq  $endLabel""")
                 }
-                if(length>=16 && asmgen.zeropage.available() > 0) {
+                if(length>=16 && asmgen.zeropage.hasByteAvailable()) {
                     // allocate index var on ZP
                     val zpAddr = asmgen.zeropage.allocate(indexVar, DataType.UBYTE, stmt.position, asmgen.errors)
                     asmgen.out("""$indexVar = $zpAddr  ; auto zp UBYTE""")
@@ -581,5 +589,5 @@ $loopLabel""")
     }
 
     private fun assignLoopvar(stmt: ForLoop, range: RangeExpr) =
-        asmgen.assignExpressionToVariable(range.from, asmgen.asmVariableName(stmt.loopVar), stmt.loopVarDt(program).typeOrElse(DataType.STRUCT), stmt.definingSubroutine())
+        asmgen.assignExpressionToVariable(range.from, asmgen.asmVariableName(stmt.loopVar), stmt.loopVarDt(program).getOr(DataType.UNDEFINED), stmt.definingSubroutine)
 }

compiler/src/prog8/compiler/target/cpu6502/codegen/FunctionCallAsmGen.kt

@@ -5,7 +5,10 @@ import prog8.ast.Node
 import prog8.ast.Program
 import prog8.ast.base.*
 import prog8.ast.expressions.*
-import prog8.ast.statements.*
+import prog8.ast.statements.InlineAssembly
+import prog8.ast.statements.RegisterOrStatusflag
+import prog8.ast.statements.Subroutine
+import prog8.ast.statements.SubroutineParameter
 import prog8.compiler.AssemblyError
 import prog8.compiler.target.CpuType
 import prog8.compiler.target.cpu6502.codegen.assignment.AsmAssignSource
@@ -27,11 +30,10 @@ internal class FunctionCallAsmGen(private val program: Program, private val asmg
         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
-            val (keepAonEntry: Boolean, keepAonReturn: Boolean) = sub.shouldKeepA()
             if(regSaveOnStack)
-                asmgen.saveRegisterStack(CpuRegister.X, keepAonEntry)
+                asmgen.saveRegisterStack(CpuRegister.X, sub.shouldKeepA().saveOnEntry)
             else
-                asmgen.saveRegisterLocal(CpuRegister.X, (stmt as Node).definingSubroutine()!!)
+                asmgen.saveRegisterLocal(CpuRegister.X, (stmt as Node).definingSubroutine!!)
         }
     }
 
@@ -39,17 +41,15 @@ internal class FunctionCallAsmGen(private val program: Program, private val asmg
         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
-            val (keepAonEntry: Boolean, keepAonReturn: Boolean) = sub.shouldKeepA()
-
             if(regSaveOnStack)
-                asmgen.restoreRegisterStack(CpuRegister.X, keepAonReturn)
+                asmgen.restoreRegisterStack(CpuRegister.X, sub.shouldKeepA().saveOnReturn)
             else
                 asmgen.restoreRegisterLocal(CpuRegister.X)
         }
     }
 
     internal fun translateFunctionCall(stmt: IFunctionCall) {
-        // Output only the code to setup the parameters and perform the actual call
+        // 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)
@@ -111,17 +111,22 @@ internal class FunctionCallAsmGen(private val program: Program, private val asmg
             }
         }
 
-        if(sub.inline && asmgen.options.optimize) {
-            if(sub.containsDefinedVariables())
-                throw AssemblyError("can't inline sub with vars")
-            if(!sub.isAsmSubroutine && sub.parameters.isNotEmpty())
-                throw AssemblyError("can't inline a non-asm subroutine with parameters")
-            asmgen.out("  \t; inlined routine follows: ${sub.name} from ${sub.position}")
-            val statements = sub.statements.filter { it !is ParameterVarDecl && it !is Directive }
-            statements.forEach { asmgen.translate(it) }
-        }
-        else {
+        if(!sub.inline || !asmgen.options.optimize) {
             asmgen.out("  jsr  $subName")
+        } else {
+            // 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)
+
+            // note: for now, this is only reliably supported for asmsubs.
+            if(!sub.isAsmSubroutine)
+                throw AssemblyError("can only reliably inline asmsub routines at this time")
+
+            asmgen.out("  \t; inlined routine follows: ${sub.name}")
+            val assembly = sub.statements.single() as InlineAssembly
+            asmgen.translate(assembly)
+            asmgen.out("  \t; inlined routine end: ${sub.name}")
         }
 
         // remember: dealing with the X register and/or dealing with return values is the responsibility of the caller
@@ -168,21 +173,31 @@ internal class FunctionCallAsmGen(private val program: Program, private val asmg
                     when (sub.parameters[argi.index].type) {
                         in ByteDatatypes -> {
                             // only load the lsb of the virtual register
-                            asmgen.out("""
+                            asmgen.out(
+                                """
                                 lda  P8ESTACK_LO$plusIdxStr,x
-                                sta  cx16.${argi.value.second.registerOrPair.toString().toLowerCase()}
+                                sta  cx16.${argi.value.second.registerOrPair.toString().lowercase()}
                             """)
                             if (asmgen.isTargetCpu(CpuType.CPU65c02))
-                                asmgen.out("  stz  cx16.${argi.value.second.registerOrPair.toString().toLowerCase()}+1")
+                                asmgen.out(
+                                    "  stz  cx16.${
+                                        argi.value.second.registerOrPair.toString().lowercase()
+                                    }+1")
                             else
-                                asmgen.out("  lda  #0 |  sta  cx16.${argi.value.second.registerOrPair.toString().toLowerCase()}+1")
+                                asmgen.out(
+                                    "  lda  #0 |  sta  cx16.${
+                                        argi.value.second.registerOrPair.toString().lowercase()
+                                    }+1")
                         }
                         in WordDatatypes, in IterableDatatypes ->
-                            asmgen.out("""
+                            asmgen.out(
+                                """
                                 lda  P8ESTACK_LO$plusIdxStr,x
-                                sta  cx16.${argi.value.second.registerOrPair.toString().toLowerCase()}
+                                sta  cx16.${argi.value.second.registerOrPair.toString().lowercase()}
                                 lda  P8ESTACK_HI$plusIdxStr,x
-                                sta  cx16.${argi.value.second.registerOrPair.toString().toLowerCase()}+1
+                                sta  cx16.${
+                                    argi.value.second.registerOrPair.toString().lowercase()
+                                }+1
                             """)
                         else -> throw AssemblyError("weird dt")
                     }
@@ -237,7 +252,7 @@ internal class FunctionCallAsmGen(private val program: Program, private val asmg
         val valueIDt = value.inferType(program)
         if(!valueIDt.isKnown)
             throw AssemblyError("unknown dt")
-        val valueDt = valueIDt.typeOrElse(DataType.STRUCT)
+        val valueDt = valueIDt.getOr(DataType.UNDEFINED)
         if(!isArgumentTypeCompatible(valueDt, parameter.value.type))
             throw AssemblyError("argument type incompatible")
 
@@ -250,7 +265,7 @@ internal class FunctionCallAsmGen(private val program: Program, private val asmg
         val valueIDt = value.inferType(program)
         if(!valueIDt.isKnown)
             throw AssemblyError("unknown dt")
-        val valueDt = valueIDt.typeOrElse(DataType.STRUCT)
+        val valueDt = valueIDt.getOr(DataType.UNDEFINED)
         if(!isArgumentTypeCompatible(valueDt, parameter.value.type))
             throw AssemblyError("argument type incompatible")
 
@@ -302,10 +317,9 @@ internal class FunctionCallAsmGen(private val program: Program, private val asmg
             register!!
             if(requiredDt largerThan valueDt) {
                 // we need to sign extend the source, do this via temporary word variable
-                val scratchVar = asmgen.asmVariableName("P8ZP_SCRATCH_W1")
-                asmgen.assignExpressionToVariable(value, scratchVar, DataType.UBYTE, sub)
-                asmgen.signExtendVariableLsb(scratchVar, valueDt)
-                asmgen.assignVariableToRegister(scratchVar, register)
+                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))

compiler/src/prog8/compiler/target/cpu6502/codegen/PostIncrDecrAsmGen.kt

@@ -15,11 +15,11 @@ internal class PostIncrDecrAsmGen(private val program: Program, private val asmg
         val targetIdent = stmt.target.identifier
         val targetMemory = stmt.target.memoryAddress
         val targetArrayIdx = stmt.target.arrayindexed
-        val scope = stmt.definingSubroutine()
+        val scope = stmt.definingSubroutine
         when {
             targetIdent!=null -> {
                 val what = asmgen.asmVariableName(targetIdent)
-                when (stmt.target.inferType(program).typeOrElse(DataType.STRUCT)) {
+                when (stmt.target.inferType(program).getOr(DataType.UNDEFINED)) {
                     in ByteDatatypes -> asmgen.out(if (incr) "  inc  $what" else "  dec  $what")
                     in WordDatatypes -> {
                         if(incr)
@@ -65,7 +65,7 @@ internal class PostIncrDecrAsmGen(private val program: Program, private val asmg
             }
             targetArrayIdx!=null -> {
                 val asmArrayvarname = asmgen.asmVariableName(targetArrayIdx.arrayvar)
-                val elementDt = targetArrayIdx.inferType(program).typeOrElse(DataType.STRUCT)
+                val elementDt = targetArrayIdx.inferType(program).getOr(DataType.UNDEFINED)
                 val constIndex = targetArrayIdx.indexer.constIndex()
                 if(constIndex!=null) {
                     val indexValue = constIndex * program.memsizer.memorySize(elementDt)

compiler/src/prog8/compiler/target/cpu6502/codegen/assignment/AsmAssignment.kt

@@ -59,11 +59,11 @@ internal class AsmAssignTarget(val kind: TargetStorageKind,
             val idt = inferType(program)
             if(!idt.isKnown)
                 throw AssemblyError("unknown dt")
-            val dt = idt.typeOrElse(DataType.STRUCT)
+            val dt = idt.getOr(DataType.UNDEFINED)
             when {
-                identifier != null -> AsmAssignTarget(TargetStorageKind.VARIABLE, program, asmgen, dt, assign.definingSubroutine(), variableAsmName = asmgen.asmVariableName(identifier!!), origAstTarget =  this)
-                arrayindexed != null -> AsmAssignTarget(TargetStorageKind.ARRAY, program, asmgen, dt, assign.definingSubroutine(), array = arrayindexed, origAstTarget =  this)
-                memoryAddress != null -> AsmAssignTarget(TargetStorageKind.MEMORY, program, asmgen, dt, assign.definingSubroutine(), memory =  memoryAddress, origAstTarget =  this)
+                identifier != null -> AsmAssignTarget(TargetStorageKind.VARIABLE, program, asmgen, dt, assign.definingSubroutine, variableAsmName = asmgen.asmVariableName(identifier!!), origAstTarget =  this)
+                arrayindexed != null -> AsmAssignTarget(TargetStorageKind.ARRAY, program, asmgen, dt, assign.definingSubroutine, array = arrayindexed, origAstTarget =  this)
+                memoryAddress != null -> AsmAssignTarget(TargetStorageKind.MEMORY, program, asmgen, dt, assign.definingSubroutine, memory =  memoryAddress, origAstTarget =  this)
                 else -> throw AssemblyError("weird target")
             }
         }
@@ -132,12 +132,12 @@ internal class AsmAssignSource(val kind: SourceStorageKind,
                 is StringLiteralValue -> throw AssemblyError("string literal value should not occur anymore for asm generation")
                 is ArrayLiteralValue -> throw AssemblyError("array literal value should not occur anymore for asm generation")
                 is IdentifierReference -> {
-                    val dt = value.inferType(program).typeOrElse(DataType.STRUCT)
+                    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.toLowerCase().startsWith("cx16.r")) {
-                        val regStr = varName.toLowerCase().substring(5)
-                        val reg = RegisterOrPair.valueOf(regStr.toUpperCase())
+                    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)
@@ -147,7 +147,7 @@ internal class AsmAssignSource(val kind: SourceStorageKind,
                     AsmAssignSource(SourceStorageKind.MEMORY, program, asmgen, DataType.UBYTE, memory = value)
                 }
                 is ArrayIndexedExpression -> {
-                    val dt = value.inferType(program).typeOrElse(DataType.STRUCT)
+                    val dt = value.inferType(program).getOr(DataType.UNDEFINED)
                     AsmAssignSource(SourceStorageKind.ARRAY, program, asmgen, dt, array = value)
                 }
                 is FunctionCall -> {
@@ -162,7 +162,7 @@ internal class AsmAssignSource(val kind: SourceStorageKind,
                             val returnType = value.inferType(program)
                             if(!returnType.isKnown)
                                 throw AssemblyError("unknown dt")
-                            AsmAssignSource(SourceStorageKind.EXPRESSION, program, asmgen, returnType.typeOrElse(DataType.STRUCT), expression = value)
+                            AsmAssignSource(SourceStorageKind.EXPRESSION, program, asmgen, returnType.getOr(DataType.UNDEFINED), expression = value)
                         }
                         else -> {
                             throw AssemblyError("weird call")
@@ -173,7 +173,7 @@ internal class AsmAssignSource(val kind: SourceStorageKind,
                     val dt = value.inferType(program)
                     if(!dt.isKnown)
                         throw AssemblyError("unknown dt")
-                    AsmAssignSource(SourceStorageKind.EXPRESSION, program, asmgen, dt.typeOrElse(DataType.STRUCT), expression = value)
+                    AsmAssignSource(SourceStorageKind.EXPRESSION, program, asmgen, dt.getOr(DataType.UNDEFINED), expression = value)
                 }
             }
         }
@@ -206,7 +206,7 @@ internal class AsmAssignment(val source: AsmAssignSource,
 
     init {
         if(target.register !in setOf(RegisterOrPair.XY, RegisterOrPair.AX, RegisterOrPair.AY))
-            require(source.datatype != DataType.STRUCT) { "must not be placeholder datatype" }
+            require(source.datatype != DataType.UNDEFINED) { "must not be placeholder/undefined datatype" }
             require(memsizer.memorySize(source.datatype) <= memsizer.memorySize(target.datatype)) {
                 "source storage size must be less or equal to target datatype storage size"
             }

compiler/src/prog8/compiler/target/cpu6502/codegen/assignment/AssignmentAsmGen.kt

@@ -115,7 +115,7 @@ internal class AssignmentAsmGen(private val program: Program, private val asmgen
             }
             SourceStorageKind.MEMORY -> {
                 fun assignViaExprEval(expression: Expression) {
-                    assignExpressionToVariable(expression, asmgen.asmVariableName("P8ZP_SCRATCH_W2"), DataType.UWORD, assign.target.scope)
+                    assignExpressionToVariable(expression, "P8ZP_SCRATCH_W2", DataType.UWORD, assign.target.scope)
                     if (asmgen.isTargetCpu(CpuType.CPU65c02))
                         asmgen.out("  lda  (P8ZP_SCRATCH_W2)")
                     else
@@ -145,7 +145,7 @@ internal class AssignmentAsmGen(private val program: Program, private val asmgen
             SourceStorageKind.EXPRESSION -> {
                 when(val value = assign.source.expression!!) {
                     is AddressOf -> {
-                        val sourceName = value.identifier.firstStructVarName(program) ?: asmgen.asmVariableName(value.identifier)
+                        val sourceName = asmgen.asmSymbolName(value.identifier)
                         assignAddressOf(assign.target, sourceName)
                     }
                     is NumericLiteralValue -> throw AssemblyError("source kind should have been literalnumber")
@@ -217,7 +217,7 @@ internal class AssignmentAsmGen(private val program: Program, private val asmgen
                                     val returntype = builtinFunctionReturnType(sub.name, value.args, program)
                                     if(!returntype.isKnown)
                                         throw AssemblyError("unknown dt")
-                                    when(returntype.typeOrElse(DataType.STRUCT)) {
+                                    when(returntype.getOr(DataType.UNDEFINED)) {
                                         in ByteDatatypes -> assignRegisterByte(assign.target, CpuRegister.A)            // function's byte result is in A
                                         in WordDatatypes -> assignRegisterpairWord(assign.target, RegisterOrPair.AY)    // function's word result is in AY
                                         DataType.STR -> {
@@ -299,7 +299,7 @@ internal class AssignmentAsmGen(private val program: Program, private val asmgen
         val valueIDt = value.inferType(program)
         if(!valueIDt.isKnown)
             throw AssemblyError("unknown dt")
-        val valueDt = valueIDt.typeOrElse(DataType.STRUCT)
+        val valueDt = valueIDt.getOr(DataType.UNDEFINED)
         if(valueDt==targetDt)
             throw AssemblyError("type cast to identical dt should have been removed")
 
@@ -320,7 +320,7 @@ internal class AssignmentAsmGen(private val program: Program, private val asmgen
                 if(targetDt in WordDatatypes) {
 
                     fun assignViaExprEval(addressExpression: Expression) {
-                        asmgen.assignExpressionToVariable(addressExpression, asmgen.asmVariableName("P8ZP_SCRATCH_W2"), DataType.UWORD, null)
+                        asmgen.assignExpressionToVariable(addressExpression, "P8ZP_SCRATCH_W2", DataType.UWORD, null)
                         if (asmgen.isTargetCpu(CpuType.CPU65c02))
                             asmgen.out("  lda  (P8ZP_SCRATCH_W2)")
                         else
@@ -359,7 +359,7 @@ internal class AssignmentAsmGen(private val program: Program, private val asmgen
 
         // special case optimizations
         if(target.kind== TargetStorageKind.VARIABLE) {
-            if(value is IdentifierReference && valueDt != DataType.STRUCT)
+            if(value is IdentifierReference && valueDt != DataType.UNDEFINED)
                 return assignTypeCastedIdentifier(target.asmVarname, targetDt, asmgen.asmVariableName(value), valueDt)
 
             when (valueDt) {
@@ -398,7 +398,7 @@ internal class AssignmentAsmGen(private val program: Program, private val asmgen
                 RegisterOrPair.A,
                 RegisterOrPair.X,
                 RegisterOrPair.Y -> {
-                    // 'cast' a ubyte value to a byte register; no cast needed at all
+                    // 'cast' an ubyte value to a byte register; no cast needed at all
                     return assignExpressionToRegister(value, target.register)
                 }
                 RegisterOrPair.AX,
@@ -431,8 +431,8 @@ internal class AssignmentAsmGen(private val program: Program, private val asmgen
         }
 
         // give up, do it via eval stack
-        // TODO optimize typecasts for more special cases?
         // note: cannot use assignTypeCastedValue because that is ourselves :P
+        // TODO optimize typecasts for more special cases?
         if(this.asmgen.options.slowCodegenWarnings)
             println("warning: slow stack evaluation used for typecast: $value into $targetDt (target=${target.kind} at ${value.position}")
         asmgen.translateExpression(origTypeCastExpression)      // this performs the actual type cast in translateExpression(Typecast)
@@ -587,13 +587,19 @@ internal class AssignmentAsmGen(private val program: Program, private val asmgen
             DataType.UBYTE -> {
                 when(targetDt) {
                     DataType.UBYTE, DataType.BYTE -> {
-                        asmgen.out("  st${regs.toString().toLowerCase()}  $targetAsmVarName")
+                        asmgen.out("  st${regs.toString().lowercase()}  $targetAsmVarName")
                     }
                     DataType.UWORD, DataType.WORD -> {
                         if(asmgen.isTargetCpu(CpuType.CPU65c02))
-                            asmgen.out("  st${regs.toString().toLowerCase()}  $targetAsmVarName |  stz  $targetAsmVarName+1")
+                            asmgen.out(
+                                "  st${
+                                    regs.toString().lowercase()
+                                }  $targetAsmVarName |  stz  $targetAsmVarName+1")
                         else
-                            asmgen.out("  st${regs.toString().toLowerCase()}  $targetAsmVarName |  lda  #0  |  sta  $targetAsmVarName+1")
+                            asmgen.out(
+                                "  st${
+                                    regs.toString().lowercase()
+                                }  $targetAsmVarName |  lda  #0  |  sta  $targetAsmVarName+1")
                     }
                     DataType.FLOAT -> {
                         when(regs) {
@@ -615,13 +621,19 @@ internal class AssignmentAsmGen(private val program: Program, private val asmgen
             DataType.BYTE -> {
                 when(targetDt) {
                     DataType.UBYTE, DataType.BYTE -> {
-                        asmgen.out("  st${regs.toString().toLowerCase()}  $targetAsmVarName")
+                        asmgen.out("  st${regs.toString().lowercase()}  $targetAsmVarName")
                     }
                     DataType.UWORD -> {
                         if(asmgen.isTargetCpu(CpuType.CPU65c02))
-                            asmgen.out("  st${regs.toString().toLowerCase()}  $targetAsmVarName |  stz  $targetAsmVarName+1")
+                            asmgen.out(
+                                "  st${
+                                    regs.toString().lowercase()
+                                }  $targetAsmVarName |  stz  $targetAsmVarName+1")
                         else
-                            asmgen.out("  st${regs.toString().toLowerCase()}  $targetAsmVarName |  lda  #0  |  sta  $targetAsmVarName+1")
+                            asmgen.out(
+                                "  st${
+                                    regs.toString().lowercase()
+                                }  $targetAsmVarName |  lda  #0  |  sta  $targetAsmVarName+1")
                     }
                     DataType.WORD -> {
                         when(regs) {
@@ -653,7 +665,7 @@ internal class AssignmentAsmGen(private val program: Program, private val asmgen
             DataType.UWORD -> {
                 when(targetDt) {
                     DataType.BYTE, DataType.UBYTE -> {
-                        asmgen.out("  st${regs.toString().toLowerCase().first()}  $targetAsmVarName")
+                        asmgen.out("  st${regs.toString().lowercase().first()}  $targetAsmVarName")
                     }
                     DataType.WORD, DataType.UWORD -> {
                         when(regs) {
@@ -681,7 +693,7 @@ internal class AssignmentAsmGen(private val program: Program, private val asmgen
             DataType.WORD -> {
                 when(targetDt) {
                     DataType.BYTE, DataType.UBYTE -> {
-                        asmgen.out("  st${regs.toString().toLowerCase().first()}  $targetAsmVarName")
+                        asmgen.out("  st${regs.toString().lowercase().first()}  $targetAsmVarName")
                     }
                     DataType.WORD, DataType.UWORD -> {
                         when(regs) {
@@ -822,12 +834,13 @@ internal class AssignmentAsmGen(private val program: Program, private val asmgen
                             RegisterOrPair.AX -> asmgen.out(" inx |  txy |  ldx  #0 |  lda  P8ESTACK_LO,y")
                             RegisterOrPair.AY -> asmgen.out(" inx |  ldy  #0 |  lda  P8ESTACK_LO,x")
                             in Cx16VirtualRegisters -> {
-                                asmgen.out("""
+                                asmgen.out(
+                                    """
                                     inx
                                     lda  P8ESTACK_LO,x
-                                    sta  cx16.${target.register.toString().toLowerCase()}
+                                    sta  cx16.${target.register.toString().lowercase()}
                                     lda  #0
-                                    sta  cx16.${target.register.toString().toLowerCase()}+1
+                                    sta  cx16.${target.register.toString().lowercase()}+1
                                 """)
                             }
                             else -> throw AssemblyError("can't assign byte from stack to register pair XY")
@@ -839,12 +852,13 @@ internal class AssignmentAsmGen(private val program: Program, private val asmgen
                             RegisterOrPair.AY-> asmgen.out(" inx |  ldy  P8ESTACK_HI,x |  lda  P8ESTACK_LO,x")
                             RegisterOrPair.XY-> throw AssemblyError("can't load X from stack here - use intermediary var? ${target.origAstTarget?.position}")
                             in Cx16VirtualRegisters -> {
-                                asmgen.out("""
+                                asmgen.out(
+                                    """
                                     inx
                                     lda  P8ESTACK_LO,x
-                                    sta  cx16.${target.register.toString().toLowerCase()}
+                                    sta  cx16.${target.register.toString().lowercase()}
                                     lda  P8ESTACK_HI,x
-                                    sta  cx16.${target.register.toString().toLowerCase()}+1
+                                    sta  cx16.${target.register.toString().lowercase()}+1
                                 """)
                             }
                             else -> throw AssemblyError("can't assign word to single byte register")
@@ -888,11 +902,12 @@ internal class AssignmentAsmGen(private val program: Program, private val asmgen
                     RegisterOrPair.AY -> asmgen.out("  ldy  #>$sourceName |  lda  #<$sourceName")
                     RegisterOrPair.XY -> asmgen.out("  ldy  #>$sourceName |  ldx  #<$sourceName")
                     in Cx16VirtualRegisters -> {
-                        asmgen.out("""
+                        asmgen.out(
+                            """
                             lda  #<$sourceName
-                            sta  cx16.${target.register.toString().toLowerCase()}
+                            sta  cx16.${target.register.toString().lowercase()}
                             lda  #>$sourceName
-                            sta  cx16.${target.register.toString().toLowerCase()}+1
+                            sta  cx16.${target.register.toString().lowercase()}+1
                         """)
                     }
                     else -> throw AssemblyError("can't load address in a single 8-bit register")
@@ -1029,11 +1044,12 @@ internal class AssignmentAsmGen(private val program: Program, private val asmgen
                     RegisterOrPair.AY -> asmgen.out("  ldy  $sourceName+1 |  lda  $sourceName")
                     RegisterOrPair.XY -> asmgen.out("  ldy  $sourceName+1 |  ldx  $sourceName")
                     in Cx16VirtualRegisters -> {
-                        asmgen.out("""
+                        asmgen.out(
+                            """
                             lda  $sourceName
-                            sta  cx16.${target.register.toString().toLowerCase()}
+                            sta  cx16.${target.register.toString().lowercase()}
                             lda  $sourceName+1
-                            sta  cx16.${target.register.toString().toLowerCase()}+1
+                            sta  cx16.${target.register.toString().lowercase()}+1
                         """)
                     }
                     else -> throw AssemblyError("can't load word in a single 8-bit register")
@@ -1203,11 +1219,12 @@ internal class AssignmentAsmGen(private val program: Program, private val asmgen
                     RegisterOrPair.XY -> asmgen.out("  ldy  #0 |  ldx  $sourceName")
                     RegisterOrPair.FAC1, RegisterOrPair.FAC2 -> throw AssemblyError("expected typecasted byte to float")
                     in Cx16VirtualRegisters -> {
-                        asmgen.out("""
+                        asmgen.out(
+                            """
                             lda  $sourceName
-                            sta  cx16.${target.register.toString().toLowerCase()}
+                            sta  cx16.${target.register.toString().lowercase()}
                             lda  #0
-                            sta  cx16.${target.register.toString().toLowerCase()}+1
+                            sta  cx16.${target.register.toString().lowercase()}+1
                             """)
                     }
                     else -> throw AssemblyError("weird register")
@@ -1236,11 +1253,20 @@ internal class AssignmentAsmGen(private val program: Program, private val asmgen
                     """)
             }
             TargetStorageKind.ARRAY -> {
-                // TODO optimize slow stack evaluation for this case, see assignVariableUByteIntoWord
-                if(this.asmgen.options.slowCodegenWarnings)
-                    println("warning: slow stack evaluation used for sign-extend byte typecast at ${bytevar.position}")
-                asmgen.translateExpression(wordtarget.origAssign.source.expression!!)
-                assignStackValue(wordtarget)
+                if (wordtarget.constArrayIndexValue!=null) {
+                    val scaledIdx = wordtarget.constArrayIndexValue!! * 2
+                    asmgen.out("  lda  $sourceName")
+                    asmgen.signExtendAYlsb(DataType.BYTE)
+                    asmgen.out("  sta  ${wordtarget.asmVarname}+$scaledIdx |  sty  ${wordtarget.asmVarname}+$scaledIdx+1")
+                }
+                else {
+                    asmgen.saveRegisterLocal(CpuRegister.X, wordtarget.scope!!)
+                    asmgen.loadScaledArrayIndexIntoRegister(wordtarget.array!!, wordtarget.datatype, CpuRegister.X)
+                    asmgen.out("  lda  $sourceName")
+                    asmgen.signExtendAYlsb(DataType.BYTE)
+                    asmgen.out("  sta  ${wordtarget.asmVarname},x |  inx |  tya |  sta  ${wordtarget.asmVarname},x")
+                    asmgen.restoreRegisterLocal(CpuRegister.X)
+                }
             }
             TargetStorageKind.REGISTER -> {
                 when(wordtarget.register!!) {
@@ -1333,8 +1359,10 @@ internal class AssignmentAsmGen(private val program: Program, private val asmgen
     }
 
     internal fun assignRegisterByte(target: AsmAssignTarget, register: CpuRegister) {
-        // we make an exception in the type check for assigning something to a cx16 virtual register
-        if(target.register !in Cx16VirtualRegisters) {
+        // we make an exception in the type check for assigning something to a cx16 virtual register, or a register pair
+        // these will be correctly typecasted from a byte to a word value
+        if(target.register !in Cx16VirtualRegisters &&
+            target.register!=RegisterOrPair.AX && target.register!=RegisterOrPair.AY && target.register!=RegisterOrPair.XY) {
             if(target.kind==TargetStorageKind.VARIABLE) {
                 val parts = target.asmVarname.split('.')
                 if (parts.size != 2 || parts[0] != "cx16")
@@ -1346,7 +1374,7 @@ internal class AssignmentAsmGen(private val program: Program, private val asmgen
 
         when(target.kind) {
             TargetStorageKind.VARIABLE -> {
-                asmgen.out("  st${register.name.toLowerCase()}  ${target.asmVarname}")
+                asmgen.out("  st${register.name.lowercase()}  ${target.asmVarname}")
             }
             TargetStorageKind.MEMORY -> {
                 when(register) {
@@ -1386,7 +1414,7 @@ internal class AssignmentAsmGen(private val program: Program, private val asmgen
                         RegisterOrPair.FAC1, RegisterOrPair.FAC2 -> throw AssemblyError("expected type cast to float")
                         in Cx16VirtualRegisters -> {
                             // only assign a single byte to the virtual register's Lsb
-                            asmgen.out("  sta  cx16.${target.register.toString().toLowerCase()}")
+                            asmgen.out("  sta  cx16.${target.register.toString().lowercase()}")
                         }
                         else -> throw AssemblyError("weird register")
                     }
@@ -1400,7 +1428,7 @@ internal class AssignmentAsmGen(private val program: Program, private val asmgen
                         RegisterOrPair.FAC1, RegisterOrPair.FAC2 -> throw AssemblyError("expected type cast to float")
                         in Cx16VirtualRegisters -> {
                             // only assign a single byte to the virtual register's Lsb
-                            asmgen.out("  stx  cx16.${target.register.toString().toLowerCase()}")
+                            asmgen.out("  stx  cx16.${target.register.toString().lowercase()}")
                         }
                         else -> throw AssemblyError("weird register")
                     }
@@ -1414,7 +1442,7 @@ internal class AssignmentAsmGen(private val program: Program, private val asmgen
                         RegisterOrPair.FAC1, RegisterOrPair.FAC2 -> throw AssemblyError("expected type cast to float")
                         in Cx16VirtualRegisters -> {
                             // only assign a single byte to the virtual register's Lsb
-                            asmgen.out("  sty  cx16.${target.register.toString().toLowerCase()}")
+                            asmgen.out("  sty  cx16.${target.register.toString().lowercase()}")
                         }
                         else -> throw AssemblyError("weird register")
                     }
@@ -1504,9 +1532,10 @@ internal class AssignmentAsmGen(private val program: Program, private val asmgen
                         RegisterOrPair.AX -> { }
                         RegisterOrPair.XY -> { asmgen.out("  stx  P8ZP_SCRATCH_REG |  ldy  P8ZP_SCRATCH_REG |  tax") }
                         in Cx16VirtualRegisters -> {
-                            asmgen.out("""
-                                    sta  cx16.${target.register.toString().toLowerCase()}
-                                    stx  cx16.${target.register.toString().toLowerCase()}+1
+                            asmgen.out(
+                                """
+                                    sta  cx16.${target.register.toString().lowercase()}
+                                    stx  cx16.${target.register.toString().lowercase()}+1
                                 """)
                         }
                         else -> throw AssemblyError("expected reg pair or cx16 virtual 16-bit register")
@@ -1516,9 +1545,10 @@ internal class AssignmentAsmGen(private val program: Program, private val asmgen
                         RegisterOrPair.AX -> { asmgen.out("  sty  P8ZP_SCRATCH_REG |  ldx  P8ZP_SCRATCH_REG") }
                         RegisterOrPair.XY -> { asmgen.out("  tax") }
                         in Cx16VirtualRegisters -> {
-                            asmgen.out("""
-                                    sta  cx16.${target.register.toString().toLowerCase()}
-                                    sty  cx16.${target.register.toString().toLowerCase()}+1
+                            asmgen.out(
+                                """
+                                    sta  cx16.${target.register.toString().lowercase()}
+                                    sty  cx16.${target.register.toString().lowercase()}+1
                                 """)
                         }
                         else -> throw AssemblyError("expected reg pair or cx16 virtual 16-bit register")
@@ -1528,9 +1558,10 @@ internal class AssignmentAsmGen(private val program: Program, private val asmgen
                         RegisterOrPair.AX -> { asmgen.out("  txa |  sty  P8ZP_SCRATCH_REG |  ldx  P8ZP_SCRATCH_REG") }
                         RegisterOrPair.XY -> { }
                         in Cx16VirtualRegisters -> {
-                            asmgen.out("""
-                                    stx  cx16.${target.register.toString().toLowerCase()}
-                                    sty  cx16.${target.register.toString().toLowerCase()}+1
+                            asmgen.out(
+                                """
+                                    stx  cx16.${target.register.toString().lowercase()}
+                                    sty  cx16.${target.register.toString().lowercase()}+1
                                 """)
                         }
                         else -> throw AssemblyError("expected reg pair or cx16 virtual 16-bit register")
@@ -1597,7 +1628,10 @@ internal class AssignmentAsmGen(private val program: Program, private val asmgen
                         RegisterOrPair.AY -> asmgen.out("  lda  #0 |  tay")
                         RegisterOrPair.XY -> asmgen.out("  ldx  #0 |  ldy  #0")
                         in Cx16VirtualRegisters -> {
-                            asmgen.out("  stz  cx16.${target.register.toString().toLowerCase()} |  stz  cx16.${target.register.toString().toLowerCase()}+1")
+                            asmgen.out(
+                                "  stz  cx16.${
+                                    target.register.toString().lowercase()
+                                } |  stz  cx16.${target.register.toString().lowercase()}+1")
                         }
                         else -> throw AssemblyError("invalid register for word value")
                     }
@@ -1647,11 +1681,12 @@ internal class AssignmentAsmGen(private val program: Program, private val asmgen
                     RegisterOrPair.AY -> asmgen.out("  ldy  #>${word.toHex()} |  lda  #<${word.toHex()}")
                     RegisterOrPair.XY -> asmgen.out("  ldy  #>${word.toHex()} |  ldx  #<${word.toHex()}")
                     in Cx16VirtualRegisters -> {
-                        asmgen.out("""
+                        asmgen.out(
+                            """
                             lda  #<${word.toHex()}
-                            sta  cx16.${target.register.toString().toLowerCase()}
+                            sta  cx16.${target.register.toString().lowercase()}
                             lda  #>${word.toHex()}
-                            sta  cx16.${target.register.toString().toLowerCase()}+1
+                            sta  cx16.${target.register.toString().lowercase()}+1
                             """)
                     }
                     else -> throw AssemblyError("invalid register for word value")
@@ -1698,7 +1733,10 @@ internal class AssignmentAsmGen(private val program: Program, private val asmgen
                     RegisterOrPair.XY -> asmgen.out("  ldx  #0 |  ldy  #0")
                     RegisterOrPair.FAC1, RegisterOrPair.FAC2 -> throw AssemblyError("expected typecasted byte to float")
                     in Cx16VirtualRegisters -> {
-                        asmgen.out("  stz  cx16.${target.register.toString().toLowerCase()} |  stz  cx16.${target.register.toString().toLowerCase()}+1")
+                        asmgen.out(
+                            "  stz  cx16.${
+                                target.register.toString().lowercase()
+                            } |  stz  cx16.${target.register.toString().lowercase()}+1")
                     }
                     else -> throw AssemblyError("weird register")
                 }
@@ -1738,11 +1776,17 @@ internal class AssignmentAsmGen(private val program: Program, private val asmgen
                 RegisterOrPair.XY -> asmgen.out("  ldy  #0 |  ldx  #${byte.toHex()}")
                 RegisterOrPair.FAC1, RegisterOrPair.FAC2 -> throw AssemblyError("expected typecasted byte to float")
                 in Cx16VirtualRegisters -> {
-                    asmgen.out("  lda  #${byte.toHex()} |  sta  cx16.${target.register.toString().toLowerCase()}")
+                    asmgen.out(
+                        "  lda  #${byte.toHex()} |  sta  cx16.${
+                            target.register.toString().lowercase()
+                        }")
                     if(asmgen.isTargetCpu(CpuType.CPU65c02))
-                        asmgen.out("  stz  cx16.${target.register.toString().toLowerCase()}+1\n")
+                        asmgen.out("  stz  cx16.${target.register.toString().lowercase()}+1\n")
                     else
-                        asmgen.out("  lda  #0 |  sta  cx16.${target.register.toString().toLowerCase()}+1\n")
+                        asmgen.out(
+                            "  lda  #0 |  sta  cx16.${
+                                target.register.toString().lowercase()
+                            }+1\n")
                 }
                 else -> throw AssemblyError("weird register")
             }
@@ -1918,11 +1962,12 @@ internal class AssignmentAsmGen(private val program: Program, private val asmgen
                     RegisterOrPair.XY -> asmgen.out("  ldy  #0 |  ldy  ${address.toHex()}")
                     RegisterOrPair.FAC1, RegisterOrPair.FAC2 -> throw AssemblyError("expected typecasted byte to float")
                     in Cx16VirtualRegisters -> {
-                        asmgen.out("""
+                        asmgen.out(
+                            """
                             lda  ${address.toHex()}
-                            sta  cx16.${target.register.toString().toLowerCase()}
+                            sta  cx16.${target.register.toString().lowercase()}
                             lda  #0
-                            sta  cx16.${target.register.toString().toLowerCase()}+1
+                            sta  cx16.${target.register.toString().lowercase()}+1
                         """)
                     }
                     else -> throw AssemblyError("weird register")
@@ -1958,10 +2003,11 @@ internal class AssignmentAsmGen(private val program: Program, private val asmgen
                         RegisterOrPair.XY -> asmgen.out("  tax |  ldy  #0")
                         RegisterOrPair.FAC1, RegisterOrPair.FAC2 -> throw AssemblyError("expected typecasted byte to float")
                         in Cx16VirtualRegisters -> {
-                            asmgen.out("""
-                                sta  cx16.${target.register.toString().toLowerCase()}
+                            asmgen.out(
+                                """
+                                sta  cx16.${target.register.toString().lowercase()}
                                 lda  #0
-                                sta  cx16.${target.register.toString().toLowerCase()}+1
+                                sta  cx16.${target.register.toString().lowercase()}+1
                             """)
                         }
                         else -> throw AssemblyError("weird register")
@@ -2045,7 +2091,7 @@ internal class AssignmentAsmGen(private val program: Program, private val asmgen
         fun storeViaExprEval() {
             when(addressExpr) {
                 is NumericLiteralValue, is IdentifierReference -> {
-                    assignExpressionToVariable(addressExpr, asmgen.asmVariableName("P8ZP_SCRATCH_W2"), DataType.UWORD, null)
+                    assignExpressionToVariable(addressExpr, "P8ZP_SCRATCH_W2", DataType.UWORD, null)
                     if (asmgen.isTargetCpu(CpuType.CPU65c02))
                         asmgen.out("  sta  (P8ZP_SCRATCH_W2)")
                     else
@@ -2054,7 +2100,7 @@ internal class AssignmentAsmGen(private val program: Program, private val asmgen
                 else -> {
                     // same as above but we need to save the A register
                     asmgen.out("  pha")
-                    assignExpressionToVariable(addressExpr, asmgen.asmVariableName("P8ZP_SCRATCH_W2"), DataType.UWORD, null)
+                    assignExpressionToVariable(addressExpr, "P8ZP_SCRATCH_W2", DataType.UWORD, null)
                     asmgen.out("  pla")
                     if (asmgen.isTargetCpu(CpuType.CPU65c02))
                         asmgen.out("  sta  (P8ZP_SCRATCH_W2)")

compiler/src/prog8/compiler/target/cpu6502/codegen/assignment/AugmentableAssignmentAsmGen.kt

@@ -25,7 +25,7 @@ internal class AugmentableAssignmentAsmGen(private val program: Program,
                 val itype = value.inferType(program)
                 if(!itype.isKnown)
                     throw AssemblyError("unknown dt")
-                val type = itype.typeOrElse(DataType.STRUCT)
+                val type = itype.getOr(DataType.UNDEFINED)
                 when (value.operator) {
                     "+" -> {}
                     "-" -> inplaceNegate(assign.target, type)
@@ -110,7 +110,7 @@ internal class AugmentableAssignmentAsmGen(private val program: Program,
         val ident = value as? IdentifierReference
         val memread = value as? DirectMemoryRead
 
-        when(target.kind) {
+        when (target.kind) {
             TargetStorageKind.VARIABLE -> {
                 when (target.datatype) {
                     in ByteDatatypes -> {
@@ -160,7 +160,7 @@ internal class AugmentableAssignmentAsmGen(private val program: Program,
                         when {
                             valueLv != null -> inplaceModification_byte_litval_to_variable(addr.toHex(), DataType.UBYTE, operator, valueLv.toInt())
                             ident != null -> inplaceModification_byte_variable_to_variable(addr.toHex(), DataType.UBYTE, operator, ident)
-                            // TODO more specialized code for types such as memory read etc.  -> inplaceModification_byte_memread_to_variable()
+                            memread != null -> inplaceModification_byte_memread_to_variable(addr.toHex(), DataType.UBYTE, operator, value)
                             value is TypecastExpression -> {
                                 if (tryRemoveRedundantCast(value, target, operator)) return
                                 inplaceModification_byte_value_to_variable(addr.toHex(), DataType.UBYTE, operator, value)
@@ -204,7 +204,7 @@ internal class AugmentableAssignmentAsmGen(private val program: Program,
                     when {
                         indexNum!=null -> {
                             val targetVarName = "${target.asmVarname} + ${indexNum.number.toInt()*program.memsizer.memorySize(target.datatype)}"
-                            when(target.datatype) {
+                            when (target.datatype) {
                                 in ByteDatatypes -> {
                                     when {
                                         valueLv != null -> inplaceModification_byte_litval_to_variable(targetVarName, target.datatype, operator, valueLv.toInt())
@@ -244,7 +244,7 @@ internal class AugmentableAssignmentAsmGen(private val program: Program,
                             }
                         }
                         indexVar!=null -> {
-                            when(target.datatype) {
+                            when (target.datatype) {
                                 in ByteDatatypes -> {
                                     val tgt = AsmAssignTarget.fromRegisters(RegisterOrPair.A, null, program, asmgen)
                                     val assign = AsmAssignment(target.origAssign.source, tgt, false, program.memsizer, value.position)
@@ -280,7 +280,7 @@ internal class AugmentableAssignmentAsmGen(private val program: Program,
             val childIDt = value.expression.inferType(program)
             if(!childIDt.isKnown)
                 throw AssemblyError("unknown dt")
-            val childDt = childIDt.typeOrElse(DataType.STRUCT)
+            val childDt = childIDt.getOr(DataType.UNDEFINED)
             if (value.type!=DataType.FLOAT && (value.type.equalsSize(childDt) || value.type.largerThan(childDt))) {
                 // this typecast is redundant here; the rest of the code knows how to deal with the uncasted value.
                 // (works for integer types, not for float.)
@@ -293,7 +293,6 @@ internal class AugmentableAssignmentAsmGen(private val program: Program,
 
     private fun inplaceModification_byte_value_to_pointer(pointervar: IdentifierReference, operator: String, value: Expression) {
         asmgen.assignExpressionToVariable(value, "P8ZP_SCRATCH_B1", DataType.UBYTE, null)
-        val (ptrOnZp, sourceName) = asmgen.loadByteFromPointerIntoA(pointervar)
         when (operator) {
             // note: ** (power) operator requires floats.
             "+" -> asmgen.out("  clc |  adc  P8ZP_SCRATCH_B1")
@@ -324,15 +323,13 @@ internal class AugmentableAssignmentAsmGen(private val program: Program,
             "^", "xor" -> asmgen.out(" eor  P8ZP_SCRATCH_B1")
             else -> throw AssemblyError("invalid operator for in-place modification $operator")
         }
-        if(ptrOnZp)
-            asmgen.out("  sta  ($sourceName),y")
-        else
-            asmgen.out("  sta  (P8ZP_SCRATCH_W1),y")
+        val sourceName = asmgen.loadByteFromPointerIntoA(pointervar)
+        asmgen.out("  sta  ($sourceName),y")
     }
 
     private fun inplaceModification_byte_variable_to_pointer(pointervar: IdentifierReference, operator: String, value: IdentifierReference) {
         val otherName = asmgen.asmVariableName(value)
-        val (ptrOnZp, sourceName) = asmgen.loadByteFromPointerIntoA(pointervar)
+        val sourceName = asmgen.loadByteFromPointerIntoA(pointervar)
 
         when (operator) {
             // note: ** (power) operator requires floats.
@@ -364,105 +361,72 @@ internal class AugmentableAssignmentAsmGen(private val program: Program,
             "^", "xor" -> asmgen.out(" eor  $otherName")
             else -> throw AssemblyError("invalid operator for in-place modification $operator")
         }
-        if(ptrOnZp)
-            asmgen.out("  sta  ($sourceName),y")
-        else
-            asmgen.out("  sta  (P8ZP_SCRATCH_W1),y")
+        asmgen.out("  sta  ($sourceName),y")
     }
 
     private fun inplaceModification_byte_litval_to_pointer(pointervar: IdentifierReference, operator: String, value: Int) {
         when (operator) {
             // note: ** (power) operator requires floats.
             "+" -> {
-                val (ptrOnZp, sourceName) = asmgen.loadByteFromPointerIntoA(pointervar)
-                asmgen.out(" clc |  adc  #$value")
-                if(ptrOnZp)
-                    asmgen.out("  sta  ($sourceName),y")
-                else
-                    asmgen.out("  sta  (P8ZP_SCRATCH_W1),y")
+                val sourceName = asmgen.loadByteFromPointerIntoA(pointervar)
+                asmgen.out("  clc |  adc  #$value")
+                asmgen.out("  sta  ($sourceName),y")
             }
             "-" -> {
-                val (ptrOnZp, sourceName) = asmgen.loadByteFromPointerIntoA(pointervar)
-                asmgen.out(" sec |  sbc  #$value")
-                if(ptrOnZp)
-                    asmgen.out("  sta  ($sourceName),y")
-                else
-                    asmgen.out("  sta  (P8ZP_SCRATCH_W1),y")
+                val sourceName = asmgen.loadByteFromPointerIntoA(pointervar)
+                asmgen.out("  sec |  sbc  #$value")
+                asmgen.out("  sta  ($sourceName),y")
             }
             "*" -> {
-                val (ptrOnZp, sourceName) = asmgen.loadByteFromPointerIntoA(pointervar)
+                val sourceName = asmgen.loadByteFromPointerIntoA(pointervar)
                 if(value in asmgen.optimizedByteMultiplications)
                     asmgen.out("  jsr  math.mul_byte_${value}")
                 else
                     asmgen.out("  ldy  #$value |  jsr  math.multiply_bytes |  ldy  #0")
-                if(ptrOnZp)
-                    asmgen.out("  sta  ($sourceName),y")
-                else
-                    asmgen.out("  sta  (P8ZP_SCRATCH_W1),y")
+                asmgen.out("  sta  ($sourceName),y")
             }
             "/" -> {
-                val (ptrOnZp, sourceName) = asmgen.loadByteFromPointerIntoA(pointervar)
+                val sourceName = asmgen.loadByteFromPointerIntoA(pointervar)
                 if(value==0)
                     throw AssemblyError("division by zero")
                 asmgen.out("  ldy  #$value |  jsr  math.divmod_ub_asm |  tya |  ldy  #0")
-                if(ptrOnZp)
-                    asmgen.out("  sta  ($sourceName),y")
-                else
-                    asmgen.out("  sta  (P8ZP_SCRATCH_W1),y")
+                asmgen.out("  sta  ($sourceName),y")
             }
             "%" -> {
-                val (ptrOnZp, sourceName) = asmgen.loadByteFromPointerIntoA(pointervar)
+                val sourceName = asmgen.loadByteFromPointerIntoA(pointervar)
                 if(value==0)
                     throw AssemblyError("division by zero")
                 asmgen.out("  ldy  #$value |  jsr  math.divmod_ub_asm |  ldy  #0")
-                if(ptrOnZp)
-                    asmgen.out("  sta  ($sourceName),y")
-                else
-                    asmgen.out("  sta  (P8ZP_SCRATCH_W1),y")
+                asmgen.out("  sta  ($sourceName),y")
             }
             "<<" -> {
                 if (value > 0) {
-                    val (ptrOnZp, sourceName) = asmgen.loadByteFromPointerIntoA(pointervar)
+                    val sourceName = asmgen.loadByteFromPointerIntoA(pointervar)
                     repeat(value) { asmgen.out(" asl  a") }
-                    if(ptrOnZp)
-                        asmgen.out("  sta  ($sourceName),y")
-                    else
-                        asmgen.out("  sta  (P8ZP_SCRATCH_W1),y")
+                    asmgen.out("  sta  ($sourceName),y")
                 }
             }
             ">>" -> {
                 if (value > 0) {
-                    val (ptrOnZp, sourceName) = asmgen.loadByteFromPointerIntoA(pointervar)
+                    val sourceName = asmgen.loadByteFromPointerIntoA(pointervar)
                     repeat(value) { asmgen.out(" lsr  a") }
-                    if(ptrOnZp)
-                        asmgen.out("  sta  ($sourceName),y")
-                    else
-                        asmgen.out("  sta  (P8ZP_SCRATCH_W1),y")
+                    asmgen.out("  sta  ($sourceName),y")
                 }
             }
             "&", "and" -> {
-                val (ptrOnZp, sourceName) = asmgen.loadByteFromPointerIntoA(pointervar)
-                asmgen.out(" and  #$value")
-                if(ptrOnZp)
-                    asmgen.out("  sta  ($sourceName),y")
-                else
-                    asmgen.out("  sta  (P8ZP_SCRATCH_W1),y")
+                val sourceName = asmgen.loadByteFromPointerIntoA(pointervar)
+                asmgen.out("  and  #$value")
+                asmgen.out("  sta  ($sourceName),y")
             }
             "|", "or" -> {
-                val (ptrOnZp, sourceName) = asmgen.loadByteFromPointerIntoA(pointervar)
-                asmgen.out(" ora  #$value")
-                if(ptrOnZp)
-                    asmgen.out("  sta  ($sourceName),y")
-                else
-                    asmgen.out("  sta  (P8ZP_SCRATCH_W1),y")
+                val sourceName = asmgen.loadByteFromPointerIntoA(pointervar)
+                asmgen.out("  ora  #$value")
+                asmgen.out("  sta  ($sourceName),y")
             }
             "^", "xor" -> {
-                val (ptrOnZp, sourceName) = asmgen.loadByteFromPointerIntoA(pointervar)
-                asmgen.out(" eor  #$value")
-                if(ptrOnZp)
-                    asmgen.out("  sta  ($sourceName),y")
-                else
-                    asmgen.out("  sta  (P8ZP_SCRATCH_W1),y")
+                val sourceName = asmgen.loadByteFromPointerIntoA(pointervar)
+                asmgen.out("  eor  #$value")
+                asmgen.out("  sta  ($sourceName),y")
             }
             else -> throw AssemblyError("invalid operator for in-place modification $operator")
         }
@@ -672,7 +636,7 @@ internal class AugmentableAssignmentAsmGen(private val program: Program,
     }
 
     private fun inplaceModification_byte_memread_to_variable(name: String, dt: DataType, operator: String, memread: DirectMemoryRead) {
-        when(operator) {
+        when (operator) {
             "+" -> {
                 exprAsmGen.translateDirectMemReadExpression(memread, false)
                 asmgen.out("""
@@ -688,8 +652,20 @@ internal class AugmentableAssignmentAsmGen(private val program: Program,
                     sec
                     sbc  P8ZP_SCRATCH_B1
                     sta  $name""")
-                // TODO: tuned code for more operators
             }
+            "|", "or" -> {
+                exprAsmGen.translateDirectMemReadExpression(memread, false)
+                asmgen.out("  ora  $name  |  sta  $name")
+            }
+            "&", "and" -> {
+                exprAsmGen.translateDirectMemReadExpression(memread, false)
+                asmgen.out("  and  $name  |  sta  $name")
+            }
+            "^", "xor" -> {
+                exprAsmGen.translateDirectMemReadExpression(memread, false)
+                asmgen.out("  eor  $name  |  sta  $name")
+            }
+            // TODO: tuned code for more operators
             else -> {
                 inplaceModification_byte_value_to_variable(name, dt, operator, memread)
             }
@@ -697,7 +673,7 @@ internal class AugmentableAssignmentAsmGen(private val program: Program,
     }
 
     private fun inplaceModification_word_memread_to_variable(name: String, dt: DataType, operator: String, memread: DirectMemoryRead) {
-        when(operator) {
+        when (operator) {
             "+" -> {
                 exprAsmGen.translateDirectMemReadExpression(memread, false)
                 asmgen.out("""
@@ -719,8 +695,26 @@ internal class AugmentableAssignmentAsmGen(private val program: Program,
                     bcc  +
                     dec  $name+1
 +""")
-                // TODO: tuned code for more operators
             }
+            "|", "or" -> {
+                exprAsmGen.translateDirectMemReadExpression(memread, false)
+                asmgen.out("  ora  $name  |  sta  $name")
+            }
+            "&", "and" -> {
+                exprAsmGen.translateDirectMemReadExpression(memread, false)
+                asmgen.out("  and  $name  |  sta  $name")
+                if(dt in WordDatatypes) {
+                    if(asmgen.isTargetCpu(CpuType.CPU65c02))
+                        asmgen.out("  stz  $name+1")
+                    else
+                        asmgen.out("  lda  #0 |  sta  $name+1")
+                }
+            }
+            "^", "xor" -> {
+                exprAsmGen.translateDirectMemReadExpression(memread, false)
+                asmgen.out("  eor  $name  |  sta  $name")
+            }
+            // TODO: tuned code for more operators
             else -> {
                 inplaceModification_word_value_to_variable(name, dt, operator, memread)
             }
@@ -980,8 +974,7 @@ internal class AugmentableAssignmentAsmGen(private val program: Program,
 
     private fun inplaceModification_word_variable_to_variable(name: String, dt: DataType, operator: String, ident: IdentifierReference) {
         val otherName = asmgen.asmVariableName(ident)
-        val valueDt = ident.targetVarDecl(program)!!.datatype
-        when (valueDt) {
+        when (val valueDt = ident.targetVarDecl(program)!!.datatype) {
             in ByteDatatypes -> {
                 // the other variable is a BYTE type so optimize for that
                 when (operator) {
@@ -1225,7 +1218,7 @@ internal class AugmentableAssignmentAsmGen(private val program: Program,
         val valueiDt = value.inferType(program)
         if(!valueiDt.isKnown)
             throw AssemblyError("unknown dt")
-        val valueDt = valueiDt.typeOrElse(DataType.STRUCT)
+        val valueDt = valueiDt.getOr(DataType.UNDEFINED)
 
         fun multiplyVarByWordInAY() {
             asmgen.out("""
@@ -1274,7 +1267,7 @@ internal class AugmentableAssignmentAsmGen(private val program: Program,
             """)
         }
 
-        when(valueDt) {
+        when (valueDt) {
             in ByteDatatypes -> {
                 // the other variable is a BYTE type so optimize for that
                 when (operator) {
@@ -1331,21 +1324,21 @@ internal class AugmentableAssignmentAsmGen(private val program: Program,
                     }
                     "*" -> {
                         // stack contains (u) byte value, sign extend that and proceed with regular 16 bit operation
-                        // TODO use an optimized word * byte multiplication routine
+                        // TODO use an optimized word * byte multiplication routine?
                         asmgen.assignExpressionToRegister(value, RegisterOrPair.A)
                         asmgen.signExtendAYlsb(valueDt)
                         multiplyVarByWordInAY()
                     }
                     "/" -> {
                         // stack contains (u) byte value, sign extend that and proceed with regular 16 bit operation
-                        // TODO use an optimized word / byte divmod routine
+                        // TODO use an optimized word / byte divmod routine?
                         asmgen.assignExpressionToRegister(value, RegisterOrPair.A)
                         asmgen.signExtendAYlsb(valueDt)
                         divideVarByWordInAY()
                     }
                     "%" -> {
                         // stack contains (u) byte value, sign extend that and proceed with regular 16 bit operation
-                        // TODO use an optimized word / byte divmod routine
+                        // TODO use an optimized word / byte divmod routine?
                         asmgen.assignExpressionToRegister(value, RegisterOrPair.A)
                         asmgen.signExtendAYlsb(valueDt)
                         remainderVarByWordInAY()
@@ -1667,11 +1660,11 @@ internal class AugmentableAssignmentAsmGen(private val program: Program,
         if (innerCastDt == null) {
             // simple typecast where the value is the target
             when (target.datatype) {
-                DataType.UBYTE, DataType.BYTE -> { /* byte target can't be casted to anything else at all */ }
+                DataType.UBYTE, DataType.BYTE -> { /* byte target can't be typecasted to anything else at all */ }
                 DataType.UWORD, DataType.WORD -> {
                     when (outerCastDt) {
                         DataType.UBYTE, DataType.BYTE -> {
-                            when(target.kind) {
+                            when (target.kind) {
                                 TargetStorageKind.VARIABLE -> {
                                     if(asmgen.isTargetCpu(CpuType.CPU65c02))
                                         asmgen.out(" stz  ${target.asmVarname}+1")
@@ -1715,7 +1708,7 @@ internal class AugmentableAssignmentAsmGen(private val program: Program,
     private fun inplaceBooleanNot(target: AsmAssignTarget, dt: DataType) {
         when (dt) {
             DataType.UBYTE -> {
-                when(target.kind) {
+                when (target.kind) {
                     TargetStorageKind.VARIABLE -> {
                         asmgen.out("""
                             lda  ${target.asmVarname}
@@ -1737,18 +1730,15 @@ internal class AugmentableAssignmentAsmGen(private val program: Program,
                                     sta  $addr""")
                             }
                             is IdentifierReference -> {
-                                val (ptrOnZp, sourceName) = asmgen.loadByteFromPointerIntoA(mem.addressExpression as IdentifierReference)
+                                val sourceName = asmgen.loadByteFromPointerIntoA(mem.addressExpression as IdentifierReference)
                                 asmgen.out("""
                                     beq  +
                                     lda  #1
 +                                   eor  #1""")
-                                if(ptrOnZp)
-                                    asmgen.out("  sta  ($sourceName),y")
-                                else
-                                    asmgen.out("  sta  (P8ZP_SCRATCH_W1),y")
+                                asmgen.out("  sta  ($sourceName),y")
                             }
                             else -> {
-                                asmgen.assignExpressionToVariable(mem.addressExpression, asmgen.asmVariableName("P8ZP_SCRATCH_W2"), DataType.UWORD, target.scope)
+                                asmgen.assignExpressionToVariable(mem.addressExpression, "P8ZP_SCRATCH_W2", DataType.UWORD, target.scope)
                                 asmgen.out("""
                                     ldy  #0
                                     lda  (P8ZP_SCRATCH_W2),y
@@ -1765,7 +1755,7 @@ internal class AugmentableAssignmentAsmGen(private val program: Program,
                 }
             }
             DataType.UWORD -> {
-                when(target.kind) {
+                when (target.kind) {
                     TargetStorageKind.VARIABLE -> {
                         asmgen.out("""
                             lda  ${target.asmVarname}
@@ -1790,7 +1780,7 @@ internal class AugmentableAssignmentAsmGen(private val program: Program,
     private fun inplaceInvert(target: AsmAssignTarget, dt: DataType) {
         when (dt) {
             DataType.UBYTE -> {
-                when(target.kind) {
+                when (target.kind) {
                     TargetStorageKind.VARIABLE -> {
                         asmgen.out("""
                             lda  ${target.asmVarname}
@@ -1808,15 +1798,12 @@ internal class AugmentableAssignmentAsmGen(private val program: Program,
                                     sta  $addr""")
                             }
                             is IdentifierReference -> {
-                                val (ptrOnZp, sourceName) = asmgen.loadByteFromPointerIntoA(memory.addressExpression as IdentifierReference)
+                                val sourceName = asmgen.loadByteFromPointerIntoA(memory.addressExpression as IdentifierReference)
                                 asmgen.out("  eor  #255")
-                                if(ptrOnZp)
-                                    asmgen.out("  sta  ($sourceName),y")
-                                else
-                                    asmgen.out("  sta  (P8ZP_SCRATCH_W1),y")
+                                asmgen.out("  sta  ($sourceName),y")
                             }
                             else -> {
-                                asmgen.assignExpressionToVariable(memory.addressExpression, asmgen.asmVariableName("P8ZP_SCRATCH_W2"), DataType.UWORD, target.scope)
+                                asmgen.assignExpressionToVariable(memory.addressExpression, "P8ZP_SCRATCH_W2", DataType.UWORD, target.scope)
                                 asmgen.out("""
                                     ldy  #0
                                     lda  (P8ZP_SCRATCH_W2),y
@@ -1831,7 +1818,7 @@ internal class AugmentableAssignmentAsmGen(private val program: Program,
                 }
             }
             DataType.UWORD -> {
-                when(target.kind) {
+                when (target.kind) {
                     TargetStorageKind.VARIABLE -> {
                         asmgen.out("""
                             lda  ${target.asmVarname}
@@ -1869,7 +1856,7 @@ internal class AugmentableAssignmentAsmGen(private val program: Program,
                 }
             }
             DataType.WORD -> {
-                when(target.kind) {
+                when (target.kind) {
                     TargetStorageKind.VARIABLE -> {
                         asmgen.out("""
                             lda  #0
@@ -1887,7 +1874,7 @@ internal class AugmentableAssignmentAsmGen(private val program: Program,
                 }
             }
             DataType.FLOAT -> {
-                when(target.kind) {
+                when (target.kind) {
                     TargetStorageKind.VARIABLE -> {
                         // simply flip the sign bit in the float
                         asmgen.out("""

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

@@ -4,7 +4,9 @@ import prog8.compiler.*
 import prog8.compiler.target.CpuType
 import prog8.compiler.target.IMachineDefinition
 import prog8.compiler.target.c64.C64MachineDefinition
+import prog8.compiler.target.cbm.viceMonListPostfix
 import java.io.IOException
+import java.nio.file.Path
 
 internal object CX16MachineDefinition: IMachineDefinition {
 
@@ -32,10 +34,28 @@ internal object CX16MachineDefinition: IMachineDefinition {
             emptyList()
     }
 
-    override fun launchEmulator(programName: String) {
-        for(emulator in listOf("x16emu")) {
+    override fun launchEmulator(selectedEmulator: Int, programNameWithPath: Path) {
+        val emulatorName: String
+        val extraArgs: List<String>
+
+        when(selectedEmulator) {
+            1 -> {
+                emulatorName = "x16emu"
+                extraArgs = emptyList()
+            }
+            2 -> {
+                emulatorName = "box16"
+                extraArgs = listOf("-sym", "${programNameWithPath}.$viceMonListPostfix")
+            }
+            else -> {
+                System.err.println("Cx16 target only supports x16emu and box16 emulators.")
+                return
+            }
+        }
+
+        for(emulator in listOf(emulatorName)) {
             println("\nStarting Commander X16 emulator $emulator...")
-            val cmdline = listOf(emulator, "-scale", "2", "-run", "-prg", "$programName.prg")
+            val cmdline = listOf(emulator, "-scale", "2", "-run", "-prg", "${programNameWithPath}.prg") + extraArgs
             val processb = ProcessBuilder(cmdline).inheritIO()
             val process: Process
             try {

compiler/src/prog8/optimizer/BinExprSplitter.kt

@@ -1,8 +1,10 @@
 package prog8.optimizer
 
+import prog8.ast.INameScope
 import prog8.ast.Node
 import prog8.ast.Program
-import prog8.ast.expressions.*
+import prog8.ast.expressions.BinaryExpression
+import prog8.ast.expressions.augmentAssignmentOperators
 import prog8.ast.statements.AssignTarget
 import prog8.ast.statements.Assignment
 import prog8.ast.walk.AstWalker
@@ -11,7 +13,6 @@ import prog8.compiler.target.ICompilationTarget
 
 
 internal class BinExprSplitter(private val program: Program, private val compTarget: ICompilationTarget) : AstWalker() {
-    private val noModifications = emptyList<IAstModification>()
 
 //    override fun after(decl: VarDecl, parent: Node): Iterable<IAstModification> {
 // TODO somehow if we do this, the resulting code for some programs (cube3d.p8) gets hundreds of bytes larger...:
@@ -57,13 +58,14 @@ X =      BinExpr                                    X   =   LeftExpr
                 if(assignment.target isSameAs binExpr.left || assignment.target isSameAs binExpr.right)
                     return noModifications
 
-                if(isSimpleExpression(binExpr.right) && !assignment.isAugmentable) {
-                    val firstAssign = Assignment(assignment.target, binExpr.left, binExpr.left.position)
+                if(binExpr.right.isSimple && !assignment.isAugmentable) {
+                    val firstAssign = Assignment(assignment.target.copy(), binExpr.left, binExpr.left.position)
                     val targetExpr = assignment.target.toExpression()
                     val augExpr = BinaryExpression(targetExpr, binExpr.operator, binExpr.right, binExpr.right.position)
                     return listOf(
-                            IAstModification.InsertBefore(assignment, firstAssign, assignment.definingScope()),
-                            IAstModification.ReplaceNode(assignment.value, augExpr, assignment))
+                        IAstModification.ReplaceNode(binExpr, augExpr, assignment),
+                        IAstModification.InsertBefore(assignment, firstAssign, assignment.parent as INameScope)
+                    )
                 }
             }
 
@@ -75,9 +77,6 @@ X =      BinExpr                                    X   =   LeftExpr
         return noModifications
     }
 
-    private fun isSimpleExpression(expr: Expression) =
-            expr is IdentifierReference || expr is NumericLiteralValue || expr is AddressOf || expr is DirectMemoryRead || expr is StringLiteralValue || expr is ArrayLiteralValue || expr is RangeExpr
-
     private fun isSimpleTarget(target: AssignTarget, program: Program) =
             if (target.identifier!=null || target.memoryAddress!=null)
                 compTarget.isInRegularRAM(target, program)

compiler/src/prog8/optimizer/CallGraph.kt

@@ -1,139 +1,71 @@
 package prog8.optimizer
 
-import prog8.ast.INameScope
 import prog8.ast.Module
 import prog8.ast.Node
 import prog8.ast.Program
-import prog8.ast.base.DataType
-import prog8.ast.base.ParentSentinel
 import prog8.ast.base.Position
+import prog8.ast.base.VarDeclType
 import prog8.ast.expressions.AddressOf
 import prog8.ast.expressions.FunctionCall
 import prog8.ast.expressions.IdentifierReference
 import prog8.ast.statements.*
 import prog8.ast.walk.IAstVisitor
 import prog8.compiler.IErrorReporter
-import java.nio.file.Path
-
-private val alwaysKeepSubroutines = setOf(
-        Pair("main", "start")
-)
-
-private val asmJumpRx = Regex("""[\-+a-zA-Z0-9_ \t]+(jmp|jsr|bra)[ \t]+(\S+).*""", RegexOption.IGNORE_CASE)
-private val asmRefRx = Regex("""[\-+a-zA-Z0-9_ \t]+(...)[ \t]+(\S+).*""", RegexOption.IGNORE_CASE)
 
 
-class CallGraph(private val program: Program, private val asmFileLoader: (filename: String, source: Path)->String) : IAstVisitor {
+class CallGraph(private val program: Program) : IAstVisitor {
 
-    val imports = mutableMapOf<Module, List<Module>>().withDefault { mutableListOf() }
-    val importedBy = mutableMapOf<Module, List<Module>>().withDefault { mutableListOf() }
-    val calls = mutableMapOf<Subroutine, List<Subroutine>>().withDefault { mutableListOf() }
-    val calledBy = mutableMapOf<Subroutine, List<Node>>().withDefault { mutableListOf() }
-
-    // TODO  add dataflow graph: what statements use what variables - can be used to eliminate unused vars
-    val usedSymbols = mutableSetOf<Statement>()
+    val imports = mutableMapOf<Module, Set<Module>>().withDefault { setOf() }
+    val importedBy = mutableMapOf<Module, Set<Module>>().withDefault { setOf() }
+    val calls = mutableMapOf<Subroutine, Set<Subroutine>>().withDefault { setOf() }
+    val calledBy = mutableMapOf<Subroutine, Set<Node>>().withDefault { setOf() }
+    private val allIdentifiersAndTargets = mutableMapOf<Pair<IdentifierReference, Position>, Statement>()
+    private val allAssemblyNodes = mutableListOf<InlineAssembly>()
 
     init {
         visit(program)
     }
 
-    fun forAllSubroutines(scope: INameScope, sub: (s: Subroutine) -> Unit) {
-        fun findSubs(scope: INameScope) {
-            scope.statements.forEach {
-                if (it is Subroutine)
-                    sub(it)
-                if (it is INameScope)
-                    findSubs(it)
+    private val usedSubroutines: Set<Subroutine> by lazy {
+        calledBy.keys + program.entrypoint
+    }
+
+    private val usedBlocks: Set<Block> by lazy {
+        val blocksFromSubroutines = usedSubroutines.map { it.definingBlock }
+        val blocksFromLibraries = program.allBlocks.filter { it.isInLibrary }
+        val used = mutableSetOf<Block>()
+
+        allIdentifiersAndTargets.forEach {
+            if(it.key.first.definingBlock in blocksFromSubroutines) {
+                val target = it.value.definingBlock
+                used.add(target)
             }
         }
-        findSubs(scope)
+
+        used + blocksFromLibraries + program.entrypoint.definingBlock
     }
 
-    override fun visit(program: Program) {
-        super.visit(program)
-
-        program.modules.forEach {
-            it.importedBy.clear()
-            it.imports.clear()
-
-            it.importedBy.addAll(importedBy.getValue(it))
-            it.imports.addAll(imports.getValue(it))
-        }
-
-        val rootmodule = program.modules.first()
-        rootmodule.importedBy.add(rootmodule)       // don't discard root module
-    }
-
-    override fun visit(block: Block) {
-        if (block.definingModule().isLibraryModule) {
-            // make sure the block is not removed
-            addNodeAndParentScopes(block)
-        }
-
-        super.visit(block)
+    private val usedModules: Set<Module> by lazy {
+        usedBlocks.map { it.definingModule }.toSet()
     }
 
     override fun visit(directive: Directive) {
-        val thisModule = directive.definingModule()
+        val thisModule = directive.definingModule
         if (directive.directive == "%import") {
             val importedModule: Module = program.modules.single { it.name == directive.args[0].name }
-            imports[thisModule] = imports.getValue(thisModule).plus(importedModule)
-            importedBy[importedModule] = importedBy.getValue(importedModule).plus(thisModule)
-        } else if (directive.directive == "%asminclude") {
-            val asm = asmFileLoader(directive.args[0].str!!, thisModule.source)
-            val scope = directive.definingSubroutine()
-            if(scope!=null) {
-                scanAssemblyCode(asm, directive, scope)
-            }
+            imports[thisModule] = imports.getValue(thisModule) + importedModule
+            importedBy[importedModule] = importedBy.getValue(importedModule) + thisModule
         }
 
         super.visit(directive)
     }
 
-    override fun visit(identifier: IdentifierReference) {
-        // track symbol usage
-        val target = identifier.targetStatement(program)
-        if (target != null) {
-            addNodeAndParentScopes(target)
-        }
-        super.visit(identifier)
-    }
-
-    private fun addNodeAndParentScopes(stmt: Statement) {
-        usedSymbols.add(stmt)
-        var node: Node = stmt
-        do {
-            if (node is INameScope && node is Statement) {
-                usedSymbols.add(node)
-            }
-            node = node.parent
-        } while (node !is Module && node !is ParentSentinel)
-    }
-
-    override fun visit(subroutine: Subroutine) {
-        if (Pair(subroutine.definingScope().name, subroutine.name) in alwaysKeepSubroutines
-                || subroutine.definingModule().isLibraryModule) {
-            // make sure the entrypoint is mentioned in the used symbols
-            addNodeAndParentScopes(subroutine)
-        }
-        super.visit(subroutine)
-    }
-
-    override fun visit(decl: VarDecl) {
-        if (decl.autogeneratedDontRemove || decl.datatype==DataType.STRUCT)
-            addNodeAndParentScopes(decl)
-        else if(decl.parent is Block && decl.definingModule().isLibraryModule)
-            addNodeAndParentScopes(decl)
-
-        super.visit(decl)
-    }
-
     override fun visit(functionCall: FunctionCall) {
         val otherSub = functionCall.target.targetSubroutine(program)
         if (otherSub != null) {
-            functionCall.definingSubroutine()?.let { thisSub ->
-                calls[thisSub] = calls.getValue(thisSub).plus(otherSub)
-                calledBy[otherSub] = calledBy.getValue(otherSub).plus(functionCall)
+            functionCall.definingSubroutine?.let { thisSub ->
+                calls[thisSub] = calls.getValue(thisSub) + otherSub
+                calledBy[otherSub] = calledBy.getValue(otherSub) + functionCall
             }
         }
         super.visit(functionCall)
@@ -142,9 +74,9 @@ class CallGraph(private val program: Program, private val asmFileLoader: (filena
     override fun visit(functionCallStatement: FunctionCallStatement) {
         val otherSub = functionCallStatement.target.targetSubroutine(program)
         if (otherSub != null) {
-            functionCallStatement.definingSubroutine()?.let { thisSub ->
-                calls[thisSub] = calls.getValue(thisSub).plus(otherSub)
-                calledBy[otherSub] = calledBy.getValue(otherSub).plus(functionCallStatement)
+            functionCallStatement.definingSubroutine?.let { thisSub ->
+                calls[thisSub] = calls.getValue(thisSub) + otherSub
+                calledBy[otherSub] = calledBy.getValue(otherSub) + functionCallStatement
             }
         }
         super.visit(functionCallStatement)
@@ -153,9 +85,9 @@ class CallGraph(private val program: Program, private val asmFileLoader: (filena
     override fun visit(addressOf: AddressOf) {
         val otherSub = addressOf.identifier.targetSubroutine(program)
         if(otherSub!=null) {
-            addressOf.definingSubroutine()?.let { thisSub ->
-                calls[thisSub] = calls.getValue(thisSub).plus(otherSub)
-                calledBy[otherSub] = calledBy.getValue(otherSub).plus(thisSub)
+            addressOf.definingSubroutine?.let { thisSub ->
+                calls[thisSub] = calls.getValue(thisSub) + otherSub
+                calledBy[otherSub] = calledBy.getValue(otherSub) + thisSub
             }
         }
         super.visit(addressOf)
@@ -164,64 +96,20 @@ class CallGraph(private val program: Program, private val asmFileLoader: (filena
     override fun visit(jump: Jump) {
         val otherSub = jump.identifier?.targetSubroutine(program)
         if (otherSub != null) {
-            jump.definingSubroutine()?.let { thisSub ->
-                calls[thisSub] = calls.getValue(thisSub).plus(otherSub)
-                calledBy[otherSub] = calledBy.getValue(otherSub).plus(jump)
+            jump.definingSubroutine?.let { thisSub ->
+                calls[thisSub] = calls.getValue(thisSub) + otherSub
+                calledBy[otherSub] = calledBy.getValue(otherSub) + jump
             }
         }
         super.visit(jump)
     }
 
-    override fun visit(structDecl: StructDecl) {
-        usedSymbols.add(structDecl)
-        usedSymbols.addAll(structDecl.statements)
+    override fun visit(identifier: IdentifierReference) {
+        allIdentifiersAndTargets[Pair(identifier, identifier.position)] = identifier.targetStatement(program)!!
     }
 
     override fun visit(inlineAssembly: InlineAssembly) {
-        // parse inline asm for subroutine calls (jmp, jsr, bra)
-        val scope = inlineAssembly.definingSubroutine()
-        scanAssemblyCode(inlineAssembly.assembly, inlineAssembly, scope)
-        super.visit(inlineAssembly)
-    }
-
-    private fun scanAssemblyCode(asm: String, context: Statement, scope: Subroutine?) {
-        asm.lines().forEach { line ->
-            val matches = asmJumpRx.matchEntire(line)
-            if (matches != null) {
-                val jumptarget = matches.groups[2]?.value
-                if (jumptarget != null && (jumptarget[0].isLetter() || jumptarget[0] == '_')) {
-                    val node = program.namespace.lookup(jumptarget.split('.'), context)
-                    if (node is Subroutine) {
-                        if(scope!=null)
-                            calls[scope] = calls.getValue(scope).plus(node)
-                        calledBy[node] = calledBy.getValue(node).plus(context)
-                    } else if (jumptarget.contains('.')) {
-                        // maybe only the first part already refers to a subroutine
-                        val node2 = program.namespace.lookup(listOf(jumptarget.substringBefore('.')), context)
-                        if (node2 is Subroutine) {
-                            if(scope!=null)
-                                calls[scope] = calls.getValue(scope).plus(node2)
-                            calledBy[node2] = calledBy.getValue(node2).plus(context)
-                        }
-                    }
-                }
-            } else {
-                val matches2 = asmRefRx.matchEntire(line)
-                if (matches2 != null) {
-                    val target = matches2.groups[2]?.value
-                    if (target != null && (target[0].isLetter() || target[0] == '_')) {
-                        if (target.contains('.')) {
-                            val node = program.namespace.lookup(listOf(target.substringBefore('.')), context)
-                            if (node is Subroutine) {
-                                if(scope!=null)
-                                    calls[scope] = calls.getValue(scope).plus(node)
-                                calledBy[node] = calledBy.getValue(node).plus(context)
-                            }
-                        }
-                    }
-                }
-            }
-        }
+        allAssemblyNodes.add(inlineAssembly)
     }
 
     fun checkRecursiveCalls(errors: IErrorReporter) {
@@ -274,4 +162,39 @@ class CallGraph(private val program: Program, private val asmFileLoader: (filena
         recStack[sub] = false
         return false
     }
+
+    fun unused(module: Module) = module !in usedModules
+
+    fun unused(sub: Subroutine): Boolean {
+        return sub !in usedSubroutines && !nameInAssemblyCode(sub.name)
+    }
+
+    fun unused(block: Block): Boolean {
+        return block !in usedBlocks && !nameInAssemblyCode(block.name)
+    }
+
+    fun unused(decl: VarDecl): Boolean {
+        if(decl.type!=VarDeclType.VAR || decl.autogeneratedDontRemove || decl.sharedWithAsm)
+            return false
+
+        if(decl.definingBlock !in usedBlocks)
+            return false
+
+        val allReferencedVardecls = allIdentifiersAndTargets.filter { it.value is VarDecl }.map { it.value }.toSet()
+        return decl !in allReferencedVardecls // Don't check assembly just for occurrences of variables, if they're not used in prog8 itself, just kill them
+    }
+
+    private fun nameInAssemblyCode(name: String) = allAssemblyNodes.any { it.assembly.contains(name) }
+
+    inline fun unused(label: Label) = false   // just always output labels
+
+    fun unused(stmt: ISymbolStatement): Boolean {
+        return when(stmt) {
+            is Subroutine -> unused(stmt)
+            is Block -> unused(stmt)
+            is VarDecl -> unused(stmt)
+            is Label -> false   // just always output labels
+            else -> false
+        }
+    }
 }

compiler/src/prog8/optimizer/ConstantFoldingOptimizer.kt

@@ -9,12 +9,10 @@ import prog8.ast.statements.ForLoop
 import prog8.ast.statements.VarDecl
 import prog8.ast.walk.AstWalker
 import prog8.ast.walk.IAstModification
-import prog8.compiler.target.ICompilationTarget
 import kotlin.math.pow
 
 
-internal class ConstantFoldingOptimizer(private val program: Program, private val compTarget: ICompilationTarget) : AstWalker() {
-    private val noModifications = emptyList<IAstModification>()
+internal class ConstantFoldingOptimizer(private val program: Program) : AstWalker() {
 
     override fun before(memread: DirectMemoryRead, parent: Node): Iterable<IAstModification> {
         // @( &thing )  -->  thing
@@ -107,7 +105,7 @@ internal class ConstantFoldingOptimizer(private val program: Program, private va
             // 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).typeOrElse(DataType.STRUCT)
+            val leftDt = leftconst.inferType(program).getOr(DataType.UNDEFINED)
             when (leftconst.number.toDouble()) {
                 0.0 -> {
                     val value = NumericLiteralValue(leftDt, 0, expr.position)
@@ -122,11 +120,11 @@ internal class ConstantFoldingOptimizer(private val program: Program, private va
                         val value = NumericLiteralValue(leftDt, 2.0.pow(rightconst.number.toDouble()), expr.position)
                         modifications += IAstModification.ReplaceNode(expr, value, parent)
                     } else {
-                        val rightDt = expr.right.inferType(program).typeOrElse(DataType.STRUCT)
+                        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).typeOrElse(DataType.STRUCT)
+                                    is Assignment -> parent.target.inferType(program).getOr(DataType.UNDEFINED)
                                     is VarDecl -> parent.datatype
                                     else -> leftDt
                                 }
@@ -188,7 +186,7 @@ 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))
             }
@@ -224,7 +222,7 @@ internal class ConstantFoldingOptimizer(private val program: Program, private va
                     range.step
                 }
 
-            return RangeExpr(fromCast.valueOrZero(), toCast.valueOrZero(), newStep, compTarget, range.position)
+            return RangeExpr(fromCast.valueOrZero(), toCast.valueOrZero(), newStep, range.position)
         }
 
         // adjust the datatype of a range expression in for loops to the loop variable.

compiler/src/prog8/optimizer/ConstantIdentifierReplacer.kt

@@ -1,21 +1,21 @@
 package prog8.optimizer
 
+import prog8.ast.INameScope
 import prog8.ast.Node
 import prog8.ast.Program
 import prog8.ast.base.*
 import prog8.ast.expressions.*
-import prog8.ast.statements.ArrayIndex
-import prog8.ast.statements.AssignTarget
-import prog8.ast.statements.ForLoop
-import prog8.ast.statements.VarDecl
+import prog8.ast.statements.*
 import prog8.ast.walk.AstWalker
 import prog8.ast.walk.IAstModification
 import prog8.compiler.IErrorReporter
+import prog8.compiler.astprocessing.size
+import prog8.compiler.astprocessing.toConstantIntegerRange
 import prog8.compiler.target.ICompilationTarget
 
 // 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)
 internal class VarConstantValueTypeAdjuster(private val program: Program, private val errors: IErrorReporter) : AstWalker() {
-    private val noModifications = emptyList<IAstModification>()
 
     override fun after(decl: VarDecl, parent: Node): Iterable<IAstModification> {
         try {
@@ -31,6 +31,57 @@ internal class VarConstantValueTypeAdjuster(private val program: Program, privat
             errors.err(x.message, x.position)
         }
 
+        // move vardecl to the containing subroutine and add initialization assignment in its place if needed
+        if(decl.type == VarDeclType.VAR && decl.datatype in NumericDatatypes) {
+            val subroutine = decl.definingSubroutine as? INameScope
+            if(subroutine!=null && subroutine!==parent) {
+                val declValue = decl.value
+                decl.value = null
+                decl.allowInitializeWithZero = false
+                return if (declValue == null) {
+                    listOf(
+                        IAstModification.Remove(decl, parent as INameScope),
+                        IAstModification.InsertFirst(decl, subroutine)
+                    )
+                } else {
+                    val target = AssignTarget(IdentifierReference(listOf(decl.name), decl.position), null, null, decl.position)
+                    val assign = Assignment(target, declValue, decl.position)
+                    listOf(
+                        IAstModification.ReplaceNode(decl, assign, parent),
+                        IAstModification.InsertFirst(decl, subroutine)
+                    )
+                }
+            }
+        }
+        return noModifications
+    }
+
+    override fun after(range: RangeExpr, parent: Node): Iterable<IAstModification> {
+        val from = range.from.constValue(program)?.number?.toDouble()
+        val to = range.to.constValue(program)?.number?.toDouble()
+        val step = range.step.constValue(program)?.number?.toDouble()
+
+        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
     }
 }
@@ -40,7 +91,6 @@ internal class VarConstantValueTypeAdjuster(private val program: Program, privat
 // 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() {
-    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
@@ -106,16 +156,15 @@ internal class ConstantIdentifierReplacer(private val program: Program, private
                     }
                 }
                 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?.constIndex()
-                        if(declArraySize!=null && declArraySize!=rangeExpr.size())
+                        if(declArraySize!=null && declArraySize!=rangeExpr.size(compTarget))
                             errors.err("range expression size doesn't match declared array size", decl.value?.position!!)
-                        val constRange = rangeExpr.toConstantIntegerRange()
+                        val constRange = rangeExpr.toConstantIntegerRange(compTarget)
                         if(constRange!=null) {
-                            val eltType = rangeExpr.inferType(program).typeOrElse(DataType.UBYTE)
+                            val eltType = rangeExpr.inferType(program).getOr(DataType.UBYTE)
                             val newValue = if(eltType in ByteDatatypes) {
                                 ArrayLiteralValue(InferredTypes.InferredType.known(decl.datatype),
                                         constRange.map { NumericLiteralValue(eltType, it.toShort(), decl.value!!.position) }.toTypedArray(),
@@ -128,6 +177,7 @@ internal class ConstantIdentifierReplacer(private val program: Program, private
                             return listOf(IAstModification.ReplaceNode(decl.value!!, newValue, decl))
                         }
                     }
+                    val numericLv = decl.value as? NumericLiteralValue
                     if(numericLv!=null && numericLv.type== DataType.FLOAT)
                         errors.err("arraysize requires only integers here", numericLv.position)
                     val size = decl.arraysize?.constIndex() ?: return noModifications
@@ -154,21 +204,19 @@ internal class ConstantIdentifierReplacer(private val program: Program, private
                             else -> {}
                         }
                         // create the array itself, filled with the fillvalue.
-                        val array = Array(size) {fillvalue}.map { NumericLiteralValue(ArrayElementTypes.getValue(decl.datatype), it, numericLv.position) }.toTypedArray<Expression>()
+                        val array = Array(size) {fillvalue}.map { NumericLiteralValue(ArrayToElementTypes.getValue(decl.datatype), it, numericLv.position) }.toTypedArray<Expression>()
                         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?.constIndex() ?: 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?.constIndex()
-                        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(declArraySize!=null && declArraySize!=rangeExpr.size(compTarget))
+                            errors.err("range expression size (${rangeExpr.size(compTarget)}) doesn't match declared array size ($declArraySize)", decl.value?.position!!)
+                        val constRange = rangeExpr.toConstantIntegerRange(compTarget)
                         if(constRange!=null) {
                             val newValue = ArrayLiteralValue(InferredTypes.InferredType.known(DataType.ARRAY_F),
                                     constRange.map { NumericLiteralValue(DataType.FLOAT, it.toDouble(), decl.value!!.position) }.toTypedArray(),
@@ -176,22 +224,24 @@ internal class ConstantIdentifierReplacer(private val program: Program, private
                             return listOf(IAstModification.ReplaceNode(decl.value!!, newValue, decl))
                         }
                     }
-                    if(rangeExpr==null && litval!=null) {
+
+                    val numericLv = decl.value as? NumericLiteralValue
+                    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 = litval.number.toDouble()
+                        val fillvalue = numericLv.number.toDouble()
                         if (fillvalue < compTarget.machine.FLOAT_MAX_NEGATIVE || fillvalue > compTarget.machine.FLOAT_MAX_POSITIVE)
-                            errors.err("float value overflow", litval.position)
+                            errors.err("float value overflow", numericLv.position)
                         else {
                             // create the array itself, filled with the fillvalue.
-                            val array = Array(size) {fillvalue}.map { NumericLiteralValue(DataType.FLOAT, it, litval.position) }.toTypedArray<Expression>()
-                            val refValue = ArrayLiteralValue(InferredTypes.InferredType.known(DataType.ARRAY_F), array, position = litval.position)
+                            val array = Array(size) {fillvalue}.map { NumericLiteralValue(DataType.FLOAT, it, numericLv.position) }.toTypedArray<Expression>()
+                            val refValue = ArrayLiteralValue(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
-                    // this includes strings and structs
                 }
             }
         }

compiler/src/prog8/optimizer/ExpressionSimplifier.kt

@@ -25,7 +25,6 @@ import kotlin.math.pow
 internal class ExpressionSimplifier(private val program: Program) : AstWalker() {
     private val powersOfTwo = (1..16).map { (2.0).pow(it) }.toSet()
     private val negativePowersOfTwo = powersOfTwo.map { -it }.toSet()
-    private val noModifications = emptyList<IAstModification>()
 
     override fun after(typecast: TypecastExpression, parent: Node): Iterable<IAstModification> {
         val mods = mutableListOf<IAstModification>()
@@ -135,8 +134,8 @@ internal class ExpressionSimplifier(private val program: Program) : AstWalker()
             ))
         }
 
-        val leftDt = leftIDt.typeOrElse(DataType.STRUCT)
-        val rightDt = rightIDt.typeOrElse(DataType.STRUCT)
+        val leftDt = leftIDt.getOr(DataType.UNDEFINED)
+        val rightDt = rightIDt.getOr(DataType.UNDEFINED)
 
         if (expr.operator == "+" || expr.operator == "-"
                 && leftVal == null && rightVal == null
@@ -291,7 +290,7 @@ internal class ExpressionSimplifier(private val program: Program) : AstWalker()
             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 casted to word
+                    // useless lsb() of byte value that was typecasted to word
                     return listOf(IAstModification.ReplaceNode(functionCall, arg.expression, parent))
                 }
             } else {
@@ -307,10 +306,10 @@ internal class ExpressionSimplifier(private val program: Program) : AstWalker()
             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 casted to word, replace with 0
+                    // useless msb() of byte value that was typecasted to word, replace with 0
                     return listOf(IAstModification.ReplaceNode(
                             functionCall,
-                            NumericLiteralValue(valueDt.typeOrElse(DataType.UBYTE), 0, arg.expression.position),
+                            NumericLiteralValue(valueDt.getOr(DataType.UBYTE), 0, arg.expression.position),
                             parent))
                 }
             } else {
@@ -319,7 +318,7 @@ internal class ExpressionSimplifier(private val program: Program) : AstWalker()
                     // useless msb() of byte value, replace with 0
                     return listOf(IAstModification.ReplaceNode(
                             functionCall,
-                            NumericLiteralValue(argDt.typeOrElse(DataType.UBYTE), 0, arg.position),
+                            NumericLiteralValue(argDt.getOr(DataType.UBYTE), 0, arg.position),
                             parent))
                 }
             }
@@ -490,10 +489,10 @@ internal class ExpressionSimplifier(private val program: Program) : AstWalker()
                     val idt = expr.inferType(program)
                     if(!idt.isKnown)
                         throw FatalAstException("unknown dt")
-                    return NumericLiteralValue(idt.typeOrElse(DataType.STRUCT), 0, expr.position)
-                } else if (cv == 2.0) {
+                    return NumericLiteralValue(idt.getOr(DataType.UNDEFINED), 0, expr.position)
+                } else if (cv in powersOfTwo) {
                     expr.operator = "&"
-                    expr.right = NumericLiteralValue.optimalInteger(1, expr.position)
+                    expr.right = NumericLiteralValue.optimalInteger(cv!!.toInt()-1, expr.position)
                     return null
                 }
             }
@@ -514,7 +513,7 @@ internal class ExpressionSimplifier(private val program: Program) : AstWalker()
             val leftIDt = expr.left.inferType(program)
             if (!leftIDt.isKnown)
                 return null
-            val leftDt = leftIDt.typeOrElse(DataType.STRUCT)
+            val leftDt = leftIDt.getOr(DataType.UNDEFINED)
             when (cv) {
                 -1.0 -> {
                     //  '/' -> -left
@@ -591,14 +590,14 @@ internal class ExpressionSimplifier(private val program: Program) : AstWalker()
                     return expr2.left
                 }
                 in powersOfTwo -> {
-                    if (leftValue.inferType(program).typeOrElse(DataType.STRUCT) in IntegerDatatypes) {
+                    if (leftValue.inferType(program).isInteger) {
                         // times a power of two => shift left
                         val numshifts = log2(cv).toInt()
                         return BinaryExpression(expr2.left, "<<", NumericLiteralValue.optimalInteger(numshifts, expr.position), expr.position)
                     }
                 }
                 in negativePowersOfTwo -> {
-                    if (leftValue.inferType(program).typeOrElse(DataType.STRUCT) in IntegerDatatypes) {
+                    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), "<<", NumericLiteralValue.optimalInteger(numshifts, expr.position), expr.position)
@@ -622,7 +621,7 @@ internal class ExpressionSimplifier(private val program: Program) : AstWalker()
         val targetIDt = expr.left.inferType(program)
         if(!targetIDt.isKnown)
             throw FatalAstException("unknown dt")
-        when (val targetDt = targetIDt.typeOrElse(DataType.STRUCT)) {
+        when (val targetDt = targetIDt.getOr(DataType.UNDEFINED)) {
             DataType.UBYTE, DataType.BYTE -> {
                 if (amount >= 8) {
                     return NumericLiteralValue(targetDt, 0, expr.position)
@@ -657,7 +656,7 @@ internal class ExpressionSimplifier(private val program: Program) : AstWalker()
         val idt = expr.left.inferType(program)
         if(!idt.isKnown)
             throw FatalAstException("unknown dt")
-        when (idt.typeOrElse(DataType.STRUCT)) {
+        when (idt.getOr(DataType.UNDEFINED)) {
             DataType.UBYTE -> {
                 if (amount >= 8) {
                     return NumericLiteralValue.optimalInteger(0, expr.position)

compiler/src/prog8/optimizer/Extensions.kt

@@ -4,31 +4,30 @@ import prog8.ast.IBuiltinFunctions
 import prog8.ast.Program
 import prog8.compiler.IErrorReporter
 import prog8.compiler.target.ICompilationTarget
-import java.nio.file.Path
 
 
 internal fun Program.constantFold(errors: IErrorReporter, compTarget: ICompilationTarget) {
     val valuetypefixer = VarConstantValueTypeAdjuster(this, errors)
     valuetypefixer.visit(this)
-    if(errors.isEmpty()) {
+    if(errors.noErrors()) {
         valuetypefixer.applyModifications()
 
         val replacer = ConstantIdentifierReplacer(this, errors, compTarget)
         replacer.visit(this)
-        if (errors.isEmpty()) {
+        if (errors.noErrors()) {
             replacer.applyModifications()
 
             valuetypefixer.visit(this)
-            if(errors.isEmpty()) {
+            if(errors.noErrors()) {
                 valuetypefixer.applyModifications()
 
-                val optimizer = ConstantFoldingOptimizer(this, compTarget)
+                val optimizer = ConstantFoldingOptimizer(this)
                 optimizer.visit(this)
-                while (errors.isEmpty() && optimizer.applyModifications() > 0) {
+                while (errors.noErrors() && optimizer.applyModifications() > 0) {
                     optimizer.visit(this)
                 }
 
-                if (errors.isEmpty()) {
+                if (errors.noErrors()) {
                     replacer.visit(this)
                     replacer.applyModifications()
                 }
@@ -36,16 +35,15 @@ internal fun Program.constantFold(errors: IErrorReporter, compTarget: ICompilati
         }
     }
 
-    if(errors.isEmpty())
+    if(errors.noErrors())
         modules.forEach { it.linkParents(namespace) }   // re-link in final configuration
 }
 
 
 internal fun Program.optimizeStatements(errors: IErrorReporter,
                                         functions: IBuiltinFunctions,
-                                        compTarget: ICompilationTarget,
-                                        asmFileLoader: (filename: String, source: Path)->String): Int {
-    val optimizer = StatementOptimizer(this, errors, functions, compTarget, asmFileLoader)
+                                        compTarget: ICompilationTarget): Int {
+    val optimizer = StatementOptimizer(this, errors, functions, compTarget)
     optimizer.visit(this)
     val optimizationCount = optimizer.applyModifications()
 

compiler/src/prog8/optimizer/StatementOptimizer.kt

@@ -11,82 +11,80 @@ import prog8.ast.walk.AstWalker
 import prog8.ast.walk.IAstModification
 import prog8.ast.walk.IAstVisitor
 import prog8.compiler.IErrorReporter
+import prog8.compiler.astprocessing.size
 import prog8.compiler.target.ICompilationTarget
-import java.nio.file.Path
 import kotlin.math.floor
 
+internal const val retvarName = "prog8_retval"
+
 
 internal class StatementOptimizer(private val program: Program,
                                   private val errors: IErrorReporter,
                                   private val functions: IBuiltinFunctions,
-                                  private val compTarget: ICompilationTarget,
-                                  asmFileLoader: (filename: String, source: Path)->String
-) : AstWalker() {
+                                  private val compTarget: ICompilationTarget) : AstWalker() {
 
-    private val noModifications = emptyList<IAstModification>()
-    private val callgraph = CallGraph(program, asmFileLoader)
+    private val subsThatNeedReturnVariable = mutableSetOf<Triple<INameScope, DataType, Position>>()
 
-    override fun after(block: Block, parent: Node): Iterable<IAstModification> {
-        if("force_output" !in block.options()) {
-            if (block.containsNoCodeNorVars()) {
-                if(block.name != program.internedStringsModuleName)
-                    errors.warn("removing empty block '${block.name}'", block.position)
-                return listOf(IAstModification.Remove(block, parent as INameScope))
-            }
-
-            if (block !in callgraph.usedSymbols) {
-                errors.warn("removing unused block '${block.name}'", block.position)
-                return listOf(IAstModification.Remove(block, parent as INameScope))
-            }
-        }
-        return noModifications
-    }
 
     override fun after(subroutine: Subroutine, parent: Node): Iterable<IAstModification> {
-        val forceOutput = "force_output" in subroutine.definingBlock().options()
-        if(subroutine.asmAddress==null && !forceOutput) {
-            if(subroutine.containsNoCodeNorVars() && !subroutine.inline) {
-                errors.warn("removing empty subroutine '${subroutine.name}'", subroutine.position)
-                val removals = callgraph.calledBy.getValue(subroutine).map {
-                    IAstModification.Remove(it, it.definingScope())
-                }.toMutableList()
-                removals += IAstModification.Remove(subroutine, subroutine.definingScope())
-                return removals
-            }
+        for(returnvar in subsThatNeedReturnVariable) {
+            val decl = VarDecl(VarDeclType.VAR, returnvar.second, ZeropageWish.DONTCARE, null, retvarName, null,
+                isArray = false,
+                autogeneratedDontRemove = true,
+                sharedWithAsm = false,
+                position = returnvar.third
+            )
+            returnvar.first.statements.add(0, decl)
         }
-
-        if(subroutine !in callgraph.usedSymbols && !forceOutput) {
-            if(!subroutine.isAsmSubroutine) {
-                errors.warn("removing unused subroutine '${subroutine.name}'", subroutine.position)
-                return listOf(IAstModification.Remove(subroutine, subroutine.definingScope()))
-            }
-        }
-
+        subsThatNeedReturnVariable.clear()
         return noModifications
     }
 
-    override fun after(decl: VarDecl, parent: Node): Iterable<IAstModification> {
-        val forceOutput = "force_output" in decl.definingBlock().options()
-        if(decl !in callgraph.usedSymbols && !forceOutput) {
-            if(decl.type == VarDeclType.VAR)
-                errors.warn("removing unused variable '${decl.name}'", decl.position)
-
-            return listOf(IAstModification.Remove(decl, decl.definingScope()))
+    override fun before(functionCall: FunctionCall, parent: Node): Iterable<IAstModification> {
+        // if the first instruction in the called subroutine is a return statement with a simple value,
+        // remove the jump altogeter and inline the returnvalue directly.
+        val subroutine = functionCall.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, subroutine)
+                        AddressOf(scoped, orig.position)
+                    }
+                    is DirectMemoryRead -> {
+                        when(val expr = orig.addressExpression) {
+                            is NumericLiteralValue -> DirectMemoryRead(expr.copy(), orig.position)
+                            else -> return noModifications
+                        }
+                    }
+                    is IdentifierReference -> scopePrefix(orig, subroutine)
+                    is NumericLiteralValue -> orig.copy()
+                    is StringLiteralValue -> orig.copy()
+                    else -> return noModifications
+                }
+                return listOf(IAstModification.ReplaceNode(functionCall, copy, parent))
+            }
         }
-
         return noModifications
     }
 
+    private fun scopePrefix(variable: IdentifierReference, subroutine: Subroutine): IdentifierReference {
+        val scoped = subroutine.makeScopedName(variable.nameInSource.last())
+        return IdentifierReference(scoped.split('.'), variable.position)
+    }
+
     override fun after(functionCallStatement: FunctionCallStatement, parent: Node): Iterable<IAstModification> {
         if(functionCallStatement.target.nameInSource.size==1 && functionCallStatement.target.nameInSource[0] in functions.names) {
             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, functionCallStatement.definingScope()))
+                return listOf(IAstModification.Remove(functionCallStatement, functionCallStatement.definingScope))
             }
         }
 
         // 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) {
@@ -94,30 +92,29 @@ internal class StatementOptimizer(private val program: Program,
             } else {
                 arg as? IdentifierReference
             }
-            if(stringVar!=null) {
-                val vardecl = stringVar.targetVarDecl(program)!!
-                val string = vardecl.value as? StringLiteralValue
+            if(stringVar!=null && stringVar.wasStringLiteral(program)) {
+                val string = stringVar.targetVarDecl(program)?.value as? StringLiteralValue
                 if(string!=null) {
                     val pos = functionCallStatement.position
                     if (string.value.length == 1) {
                         val firstCharEncoded = compTarget.encodeString(string.value, string.altEncoding)[0]
                         val chrout = FunctionCallStatement(
-                                IdentifierReference(listOf("txt", "chrout"), pos),
-                                mutableListOf(NumericLiteralValue(DataType.UBYTE, firstCharEncoded.toInt(), pos)),
-                                functionCallStatement.void, pos
+                            IdentifierReference(listOf("txt", "chrout"), pos),
+                            mutableListOf(NumericLiteralValue(DataType.UBYTE, firstCharEncoded.toInt(), pos)),
+                            functionCallStatement.void, pos
                         )
                         return listOf(IAstModification.ReplaceNode(functionCallStatement, chrout, parent))
                     } else if (string.value.length == 2) {
                         val firstTwoCharsEncoded = compTarget.encodeString(string.value.take(2), string.altEncoding)
                         val chrout1 = FunctionCallStatement(
-                                IdentifierReference(listOf("txt", "chrout"), pos),
-                                mutableListOf(NumericLiteralValue(DataType.UBYTE, firstTwoCharsEncoded[0].toInt(), pos)),
-                                functionCallStatement.void, pos
+                            IdentifierReference(listOf("txt", "chrout"), pos),
+                            mutableListOf(NumericLiteralValue(DataType.UBYTE, firstTwoCharsEncoded[0].toInt(), pos)),
+                            functionCallStatement.void, pos
                         )
                         val chrout2 = FunctionCallStatement(
-                                IdentifierReference(listOf("txt", "chrout"), pos),
-                                mutableListOf(NumericLiteralValue(DataType.UBYTE, firstTwoCharsEncoded[1].toInt(), pos)),
-                                functionCallStatement.void, pos
+                            IdentifierReference(listOf("txt", "chrout"), pos),
+                            mutableListOf(NumericLiteralValue(DataType.UBYTE, firstTwoCharsEncoded[1].toInt(), pos)),
+                            functionCallStatement.void, pos
                         )
                         return listOf(
                             IAstModification.InsertBefore(functionCallStatement, chrout1, parent as INameScope),
@@ -133,33 +130,33 @@ internal class StatementOptimizer(private val program: 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, functionCallStatement.definingScope()))
+                return listOf(IAstModification.Remove(functionCallStatement, functionCallStatement.definingScope))
         }
 
         return noModifications
     }
 
-    override fun before(functionCall: FunctionCall, parent: Node): Iterable<IAstModification> {
-        // if the first instruction in the called subroutine is a return statement with constant value, replace with the constant value
-        val subroutine = functionCall.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!=null) {
-                val constval = first.value?.constValue(program)
-                if(constval!=null)
-                    return listOf(IAstModification.ReplaceNode(functionCall, constval, parent))
-            }
-        }
-        return noModifications
-    }
+//    override fun before(functionCall: FunctionCall, parent: Node): Iterable<IAstModification> {
+//        // if the first instruction in the called subroutine is a return statement with constant value, replace with the constant value
+//        val subroutine = functionCall.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!=null) {
+//                val constval = first.value?.constValue(program)
+//                if(constval!=null)
+//                    return listOf(IAstModification.ReplaceNode(functionCall, constval, parent))
+//            }
+//        }
+//        return noModifications
+//    }
 
     override fun after(ifStatement: IfStatement, parent: Node): Iterable<IAstModification> {
         // remove empty if statements
-        if(ifStatement.truepart.containsNoCodeNorVars() && ifStatement.elsepart.containsNoCodeNorVars())
-            return listOf(IAstModification.Remove(ifStatement, ifStatement.definingScope()))
+        if(ifStatement.truepart.containsNoCodeNorVars && ifStatement.elsepart.containsNoCodeNorVars)
+            return listOf(IAstModification.Remove(ifStatement, ifStatement.definingScope))
 
         // empty true part? switch with the else part
-        if(ifStatement.truepart.containsNoCodeNorVars() && ifStatement.elsepart.containsCodeOrVars()) {
+        if(ifStatement.truepart.containsNoCodeNorVars && ifStatement.elsepart.containsCodeOrVars) {
             val invertedCondition = PrefixExpression("not", ifStatement.condition, ifStatement.condition.position)
             val emptyscope = AnonymousScope(mutableListOf(), ifStatement.elsepart.position)
             val truepart = AnonymousScope(ifStatement.elsepart.statements, ifStatement.truepart.position)
@@ -187,20 +184,20 @@ internal class StatementOptimizer(private val program: Program,
     }
 
     override fun after(forLoop: ForLoop, parent: Node): Iterable<IAstModification> {
-        if(forLoop.body.containsNoCodeNorVars()) {
+        if(forLoop.body.containsNoCodeNorVars) {
             errors.warn("removing empty for loop", forLoop.position)
-            return listOf(IAstModification.Remove(forLoop, forLoop.definingScope()))
+            return listOf(IAstModification.Remove(forLoop, forLoop.definingScope))
         } 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, forLoop.definingScope()))
+                return listOf(IAstModification.Remove(forLoop, forLoop.definingScope))
             }
         }
 
         val range = forLoop.iterable as? RangeExpr
         if(range!=null) {
-            if(range.size()==1) {
+            if (range.size(compTarget) == 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)
@@ -271,7 +268,7 @@ internal class StatementOptimizer(private val program: Program,
             } else {
                 // always false -> remove the while statement altogether
                 errors.warn("condition is always false", whileLoop.condition.position)
-                listOf(IAstModification.Remove(whileLoop, whileLoop.definingScope()))
+                listOf(IAstModification.Remove(whileLoop, whileLoop.definingScope))
             }
         }
         return noModifications
@@ -280,14 +277,14 @@ internal class StatementOptimizer(private val program: Program,
     override fun after(repeatLoop: RepeatLoop, parent: Node): Iterable<IAstModification> {
         val iter = repeatLoop.iterations
         if(iter!=null) {
-            if(repeatLoop.body.containsNoCodeNorVars()) {
+            if(repeatLoop.body.containsNoCodeNorVars) {
                 errors.warn("empty loop removed", repeatLoop.position)
-                return listOf(IAstModification.Remove(repeatLoop, repeatLoop.definingScope()))
+                return listOf(IAstModification.Remove(repeatLoop, repeatLoop.definingScope))
             }
             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, repeatLoop.definingScope()))
+                return listOf(IAstModification.Remove(repeatLoop, repeatLoop.definingScope))
             }
             if (iterations == 1) {
                 errors.warn("iterations is always 1", iter.position)
@@ -299,10 +296,10 @@ internal class StatementOptimizer(private val program: Program,
 
     override fun after(jump: Jump, parent: Node): Iterable<IAstModification> {
         // if the jump is to the next statement, remove the jump
-        val scope = jump.definingScope()
+        val scope = jump.definingScope
         val label = jump.identifier?.targetStatement(program)
         if(label!=null && scope.statements.indexOf(label) == scope.statements.indexOf(jump)+1)
-            return listOf(IAstModification.Remove(jump, jump.definingScope()))
+            return listOf(IAstModification.Remove(jump, jump.definingScope))
 
         return noModifications
     }
@@ -335,7 +332,7 @@ internal class StatementOptimizer(private val program: Program,
                                 )
                                 return listOf(
                                         IAstModification.ReplaceNode(binExpr, expr2, binExpr.parent),
-                                        IAstModification.InsertAfter(assignment, addConstant, assignment.definingScope()))
+                                        IAstModification.InsertAfter(assignment, addConstant, assignment.definingScope))
                             } else if (op2 == "-") {
                                 // A = A +/- B - N
                                 val expr2 = BinaryExpression(binExpr.left, binExpr.operator, rExpr.left, binExpr.position)
@@ -346,7 +343,7 @@ internal class StatementOptimizer(private val program: Program,
                                 )
                                 return listOf(
                                         IAstModification.ReplaceNode(binExpr, expr2, binExpr.parent),
-                                        IAstModification.InsertAfter(assignment, subConstant, assignment.definingScope()))
+                                        IAstModification.InsertAfter(assignment, subConstant, assignment.definingScope))
                             }
                         }
                     }
@@ -368,7 +365,7 @@ internal class StatementOptimizer(private val program: Program,
     override fun after(assignment: Assignment, parent: Node): Iterable<IAstModification> {
         if(assignment.target isSameAs assignment.value) {
             // remove assignment to self
-            return listOf(IAstModification.Remove(assignment, assignment.definingScope()))
+            return listOf(IAstModification.Remove(assignment, assignment.definingScope))
         }
 
         val targetIDt = assignment.target.inferType(program)
@@ -376,7 +373,7 @@ internal class StatementOptimizer(private val program: Program,
             throw FatalAstException("can't infer type of assignment target")
 
         // optimize binary expressions a bit
-        val targetDt = targetIDt.typeOrElse(DataType.STRUCT)
+        val targetDt = targetIDt.getOr(DataType.UNDEFINED)
         val bexpr=assignment.value as? BinaryExpression
         if(bexpr!=null) {
             val rightCv = bexpr.right.constValue(program)?.number?.toDouble()
@@ -388,13 +385,13 @@ internal class StatementOptimizer(private val program: Program,
                 when (bexpr.operator) {
                     "+" -> {
                         if (rightCv == 0.0) {
-                            return listOf(IAstModification.Remove(assignment, assignment.definingScope()))
+                            return listOf(IAstModification.Remove(assignment, assignment.definingScope))
                         } 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, "++", assignment.position))
+                                    incs.statements.add(PostIncrDecr(assignment.target.copy(), "++", assignment.position))
                                 }
                                 return listOf(IAstModification.ReplaceNode(assignment, incs, parent))
                             }
@@ -402,30 +399,30 @@ internal class StatementOptimizer(private val program: Program,
                     }
                     "-" -> {
                         if (rightCv == 0.0) {
-                            return listOf(IAstModification.Remove(assignment, assignment.definingScope()))
+                            return listOf(IAstModification.Remove(assignment, assignment.definingScope))
                         } 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, "--", assignment.position))
+                                    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, assignment.definingScope()))
-                    "/" -> if (rightCv == 1.0) return listOf(IAstModification.Remove(assignment, assignment.definingScope()))
-                    "**" -> if (rightCv == 1.0) return listOf(IAstModification.Remove(assignment, assignment.definingScope()))
-                    "|" -> if (rightCv == 0.0) return listOf(IAstModification.Remove(assignment, assignment.definingScope()))
-                    "^" -> if (rightCv == 0.0) return listOf(IAstModification.Remove(assignment, assignment.definingScope()))
+                    "*" -> if (rightCv == 1.0) return listOf(IAstModification.Remove(assignment, assignment.definingScope))
+                    "/" -> if (rightCv == 1.0) return listOf(IAstModification.Remove(assignment, assignment.definingScope))
+                    "**" -> if (rightCv == 1.0) return listOf(IAstModification.Remove(assignment, assignment.definingScope))
+                    "|" -> if (rightCv == 0.0) return listOf(IAstModification.Remove(assignment, assignment.definingScope))
+                    "^" -> if (rightCv == 0.0) return listOf(IAstModification.Remove(assignment, assignment.definingScope))
                     "<<" -> {
                         if (rightCv == 0.0)
-                            return listOf(IAstModification.Remove(assignment, assignment.definingScope()))
+                            return listOf(IAstModification.Remove(assignment, assignment.definingScope))
                     }
                     ">>" -> {
                         if (rightCv == 0.0)
-                            return listOf(IAstModification.Remove(assignment, assignment.definingScope()))
+                            return listOf(IAstModification.Remove(assignment, assignment.definingScope))
                     }
                 }
 
@@ -436,21 +433,17 @@ internal class StatementOptimizer(private val program: Program,
     }
 
     override fun after(returnStmt: Return, parent: Node): Iterable<IAstModification> {
-        fun returnViaIntermediary(value: Expression): Iterable<IAstModification>? {
-            val returnDt = returnStmt.definingSubroutine()!!.returntypes.single()
+        fun returnViaIntermediaryVar(value: Expression): Iterable<IAstModification>? {
+            val subr = returnStmt.definingSubroutine!!
+            val returnDt = subr.returntypes.single()
             if (returnDt in IntegerDatatypes) {
-                // first assign to intermediary, then return that register
-                val returnValueIntermediary =
-                    when(returnDt) {
-                        DataType.UBYTE -> IdentifierReference(listOf("prog8_lib", "retval_interm_ub"), returnStmt.position)
-                        DataType.BYTE -> IdentifierReference(listOf("prog8_lib", "retval_interm_b"), returnStmt.position)
-                        DataType.UWORD -> IdentifierReference(listOf("prog8_lib", "retval_interm_uw"), returnStmt.position)
-                        DataType.WORD -> IdentifierReference(listOf("prog8_lib", "retval_interm_w"), returnStmt.position)
-                        else -> throw FatalAstException("weird return dt")
-                    }
-                val tgt = AssignTarget(returnValueIntermediary, null, null, returnStmt.position)
+                // first assign to intermediary variable, then return that
+                subsThatNeedReturnVariable.add(Triple(subr, returnDt, returnStmt.position))
+                val returnValueIntermediary1 = IdentifierReference(listOf(retvarName), returnStmt.position)
+                val returnValueIntermediary2 = IdentifierReference(listOf(retvarName), returnStmt.position)
+                val tgt = AssignTarget(returnValueIntermediary1, null, null, returnStmt.position)
                 val assign = Assignment(tgt, value, returnStmt.position)
-                val returnReplacement = Return(returnValueIntermediary, returnStmt.position)
+                val returnReplacement = Return(returnValueIntermediary2, returnStmt.position)
                 return listOf(
                     IAstModification.InsertBefore(returnStmt, assign, parent as INameScope),
                     IAstModification.ReplaceNode(returnStmt, returnReplacement, parent)
@@ -461,12 +454,12 @@ internal class StatementOptimizer(private val program: Program,
 
         when(returnStmt.value) {
             is PrefixExpression -> {
-                val mod = returnViaIntermediary(returnStmt.value!!)
+                val mod = returnViaIntermediaryVar(returnStmt.value!!)
                 if(mod!=null)
                     return mod
             }
             is BinaryExpression -> {
-                val mod = returnViaIntermediary(returnStmt.value!!)
+                val mod = returnViaIntermediaryVar(returnStmt.value!!)
                 if(mod!=null)
                     return mod
             }

compiler/src/prog8/optimizer/UnusedCodeRemover.kt

@@ -1,8 +1,7 @@
 package prog8.optimizer
 
-import prog8.ast.INameScope
-import prog8.ast.Node
-import prog8.ast.Program
+import prog8.ast.*
+import prog8.ast.base.VarDeclType
 import prog8.ast.expressions.BinaryExpression
 import prog8.ast.expressions.FunctionCall
 import prog8.ast.expressions.PrefixExpression
@@ -12,45 +11,21 @@ import prog8.ast.walk.AstWalker
 import prog8.ast.walk.IAstModification
 import prog8.compiler.IErrorReporter
 import prog8.compiler.target.ICompilationTarget
-import java.nio.file.Path
 
 
 internal class UnusedCodeRemover(private val program: Program,
                                  private val errors: IErrorReporter,
-                                 private val compTarget: ICompilationTarget,
-                                 private val asmFileLoader: (filename: String, source: Path)->String): AstWalker() {
+                                 private val compTarget: ICompilationTarget): AstWalker() {
 
-    override fun before(program: Program, parent: Node): Iterable<IAstModification> {
-        val callgraph = CallGraph(program, asmFileLoader)
-        val removals = mutableListOf<IAstModification>()
+    private val callgraph = CallGraph(program)
 
-        // remove all subroutines that aren't called, or are empty
-        // NOTE: part of this is also done already in the StatementOptimizer
-        val entrypoint = program.entrypoint()
-        program.modules.forEach {
-            callgraph.forAllSubroutines(it) { sub ->
-                val forceOutput = "force_output" in sub.definingBlock().options()
-                if (sub !== entrypoint && !forceOutput && !sub.isAsmSubroutine && (callgraph.calledBy[sub].isNullOrEmpty() || sub.containsNoCodeNorVars())) {
-                    removals.add(IAstModification.Remove(sub, sub.definingScope()))
-                }
-            }
-        }
-
-        program.modules.flatMap { it.statements }.filterIsInstance<Block>().forEach { block ->
-            if (block.containsNoCodeNorVars() && "force_output" !in block.options())
-                removals.add(IAstModification.Remove(block, block.definingScope()))
-        }
-
-        // remove modules that are not imported, or are empty (unless it's a library modules)
-        program.modules.forEach {
-            if (!it.isLibraryModule && (it.importedBy.isEmpty() || it.containsNoCodeNorVars()))
-                removals.add(IAstModification.Remove(it, it.definingScope()))
-        }
-
-        return removals
+    override fun before(module: Module, parent: Node): Iterable<IAstModification> {
+        return if (!module.isLibrary && (module.containsNoCodeNorVars || callgraph.unused(module)))
+            listOf(IAstModification.Remove(module, module.definingScope))
+        else
+            noModifications
     }
 
-
     override fun before(breakStmt: Break, parent: Node): Iterable<IAstModification> {
         reportUnreachable(breakStmt, parent as INameScope)
         return emptyList()
@@ -74,7 +49,7 @@ internal class UnusedCodeRemover(private val program: Program,
 
     private fun reportUnreachable(stmt: Statement, parent: INameScope) {
         when(val next = parent.nextSibling(stmt)) {
-            null, is Label, is Directive, is VarDecl, is InlineAssembly, is Subroutine, is StructDecl -> {}
+            null, is Label, is Directive, is VarDecl, is InlineAssembly, is Subroutine -> {}
             else -> errors.warn("unreachable code", next.position)
         }
     }
@@ -85,15 +60,60 @@ internal class UnusedCodeRemover(private val program: Program,
     }
 
     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 '${block.name}'", block.position)
+                return listOf(IAstModification.Remove(block, parent as INameScope))
+            }
+            if(callgraph.unused(block)) {
+                errors.warn("removing unused block '${block.name}'", block.position)
+                return listOf(IAstModification.Remove(block, parent as INameScope))
+            }
+        }
+
         val removeDoubleAssignments = deduplicateAssignments(block.statements)
         return removeDoubleAssignments.map { IAstModification.Remove(it, 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.definingModule.isLibrary)
+                    errors.warn("removing unused subroutine '${subroutine.name}'", subroutine.position)
+                return listOf(IAstModification.Remove(subroutine, subroutine.definingScope))
+            }
+            if(subroutine.containsNoCodeNorVars) {
+                if(!subroutine.definingModule.isLibrary)
+                    errors.warn("removing empty subroutine '${subroutine.name}'", subroutine.position)
+                val removals = mutableListOf(IAstModification.Remove(subroutine, subroutine.definingScope))
+                callgraph.calledBy[subroutine]?.let {
+                    for(node in it)
+                        removals.add(IAstModification.Remove(node, node.definingScope))
+                }
+                return removals
+            }
+        }
+
         val removeDoubleAssignments = deduplicateAssignments(subroutine.statements)
         return removeDoubleAssignments.map { IAstModification.Remove(it, subroutine) }
     }
 
+    override fun after(decl: VarDecl, parent: Node): Iterable<IAstModification> {
+        if(decl.type==VarDeclType.VAR) {
+            val forceOutput = "force_output" in decl.definingBlock.options()
+            if (!forceOutput && !decl.autogeneratedDontRemove && !decl.sharedWithAsm && !decl.definingBlock.isInLibrary) {
+                if (callgraph.unused(decl)) {
+                    errors.warn("removing unused variable '${decl.name}'", decl.position)
+                    return listOf(IAstModification.Remove(decl, decl.definingScope))
+                }
+            }
+        }
+
+        return noModifications
+    }
+
     private fun deduplicateAssignments(statements: List<Statement>): List<Assignment> {
         // removes 'duplicate' assignments that assign the same target directly after another
         val linesToRemove = mutableListOf<Assignment>()

compiler/test/AsmgenTests.kt

@@ -0,0 +1,145 @@
+package prog8tests
+
+import org.hamcrest.MatcherAssert.assertThat
+import org.hamcrest.Matchers.equalTo
+import org.junit.jupiter.api.Test
+import org.junit.jupiter.api.TestInstance
+import prog8.ast.Module
+import prog8.ast.Program
+import prog8.ast.base.*
+import prog8.ast.expressions.AddressOf
+import prog8.ast.expressions.IdentifierReference
+import prog8.ast.expressions.NumericLiteralValue
+import prog8.ast.statements.*
+import prog8.compiler.*
+import prog8.compiler.target.C64Target
+import prog8.compiler.target.c64.C64MachineDefinition
+import prog8.compiler.target.cpu6502.codegen.AsmGen
+import prog8tests.helpers.DummyFunctions
+import prog8tests.helpers.DummyMemsizer
+import java.nio.file.Path
+
+
+@TestInstance(TestInstance.Lifecycle.PER_CLASS)
+class TestAsmGen6502 {
+
+    private fun createTestProgram(): Program {
+        /*
+main  {
+
+label_outside:
+    uword var_outside
+
+    sub start () {
+        uword localvar = 1234
+        uword tgt
+
+locallabel:
+        tgt = localvar
+        tgt = &locallabel
+        tgt = &var_outside
+        tgt = &label_outside
+        tgt = &main.start.localvar
+        tgt = &main.start.locallabel
+        tgt = &main.var_outside
+        tgt = &main.label_outside
+    }
+}
+
+         */
+        val varInSub = VarDecl(VarDeclType.VAR, DataType.UWORD, ZeropageWish.DONTCARE, null, "localvar", NumericLiteralValue.optimalInteger(1234, Position.DUMMY), false, false, false, Position.DUMMY)
+        val var2InSub = VarDecl(VarDeclType.VAR, DataType.UWORD, ZeropageWish.DONTCARE, null, "tgt", null, false, false, false, Position.DUMMY)
+        val labelInSub = Label("locallabel", Position.DUMMY)
+
+        val tgt = AssignTarget(IdentifierReference(listOf("tgt"), Position.DUMMY), null, null, Position.DUMMY)
+        val assign1 = Assignment(tgt, IdentifierReference(listOf("localvar"), Position.DUMMY), Position.DUMMY)
+        val assign2 = Assignment(tgt, AddressOf(IdentifierReference(listOf("locallabel"), Position.DUMMY), Position.DUMMY), Position.DUMMY)
+        val assign3 = Assignment(tgt, AddressOf(IdentifierReference(listOf("var_outside"), Position.DUMMY), Position.DUMMY), Position.DUMMY)
+        val assign4 = Assignment(tgt, AddressOf(IdentifierReference(listOf("label_outside"), Position.DUMMY), Position.DUMMY), Position.DUMMY)
+        val assign5 = Assignment(tgt, AddressOf(IdentifierReference(listOf("main","start","localvar"), Position.DUMMY), Position.DUMMY), Position.DUMMY)
+        val assign6 = Assignment(tgt, AddressOf(IdentifierReference(listOf("main","start","locallabel"), Position.DUMMY), Position.DUMMY), Position.DUMMY)
+        val assign7 = Assignment(tgt, AddressOf(IdentifierReference(listOf("main","var_outside"), Position.DUMMY), Position.DUMMY), Position.DUMMY)
+        val assign8 = Assignment(tgt, AddressOf(IdentifierReference(listOf("main","label_outside"), Position.DUMMY), Position.DUMMY), Position.DUMMY)
+
+        val statements = mutableListOf(varInSub, var2InSub, labelInSub, assign1, assign2, assign3, assign4, assign5, assign6, assign7, assign8)
+        val subroutine = Subroutine("start", emptyList(), emptyList(), emptyList(), emptyList(), emptySet(), null, false, false, statements, Position.DUMMY)
+        val labelInBlock = Label("label_outside", Position.DUMMY)
+        val varInBlock = VarDecl(VarDeclType.VAR, DataType.UWORD, ZeropageWish.DONTCARE, null, "var_outside", null, false, false, false, Position.DUMMY)
+        val block = Block("main", null, mutableListOf(labelInBlock, varInBlock, subroutine), false, Position.DUMMY)
+
+        val module = Module("test", mutableListOf(block), Position.DUMMY, null)
+        val program = Program("test", DummyFunctions, DummyMemsizer)
+            .addModule(module)
+        module.linkParents(program.namespace)
+        return program
+    }
+
+    private fun createTestAsmGen(program: Program): AsmGen {
+        val errors = ErrorReporter()
+        val options = CompilationOptions(OutputType.RAW, LauncherType.NONE, ZeropageType.FULL, emptyList(), false, true, C64Target)
+        val zp = C64MachineDefinition.C64Zeropage(options)
+        val asmgen = AsmGen(program, errors, zp, options, C64Target, Path.of("."))
+        return asmgen
+    }
+
+    @Test
+    fun testSymbolNameFromStrings() {
+        val program = createTestProgram()
+        val asmgen = createTestAsmGen(program)
+
+        assertThat(asmgen.asmSymbolName("name"), equalTo("name"))
+        assertThat(asmgen.asmSymbolName("<name>"), equalTo("prog8_name"))
+        assertThat(asmgen.asmSymbolName(RegisterOrPair.R15), equalTo("cx16.r15"))
+        assertThat(asmgen.asmSymbolName(listOf("a", "b", "name")), equalTo("a.b.name"))
+        assertThat(asmgen.asmVariableName("name"), equalTo("name"))
+        assertThat(asmgen.asmVariableName("<name>"), equalTo("prog8_name"))
+        assertThat(asmgen.asmVariableName(listOf("a", "b", "name")), equalTo("a.b.name"))
+    }
+
+    @Test
+    fun testSymbolNameFromVarIdentifier() {
+        val program = createTestProgram()
+        val asmgen = createTestAsmGen(program)
+        val sub = program.entrypoint
+
+        // local variable
+        val localvarIdent = sub.statements.filterIsInstance<Assignment>().first { it.value is IdentifierReference }.value as IdentifierReference
+        assertThat(asmgen.asmSymbolName(localvarIdent), equalTo("localvar"))
+        assertThat(asmgen.asmVariableName(localvarIdent), equalTo("localvar"))
+        val localvarIdentScoped = (sub.statements.filterIsInstance<Assignment>().first { (it.value as? AddressOf)?.identifier?.nameInSource==listOf("main", "start", "localvar") }.value as AddressOf).identifier
+        assertThat(asmgen.asmSymbolName(localvarIdentScoped), equalTo("main.start.localvar"))
+        assertThat(asmgen.asmVariableName(localvarIdentScoped), equalTo("main.start.localvar"))
+
+        // variable from outer scope (note that for Variables, no scoping prefix symbols are required,
+        //   because they're not outputted as locally scoped symbols for the assembler
+        val scopedVarIdent = (sub.statements.filterIsInstance<Assignment>().first { (it.value as? AddressOf)?.identifier?.nameInSource==listOf("var_outside") }.value as AddressOf).identifier
+        assertThat(asmgen.asmSymbolName(scopedVarIdent), equalTo("main.var_outside"))
+        assertThat(asmgen.asmVariableName(scopedVarIdent), equalTo("var_outside"))
+        val scopedVarIdentScoped = (sub.statements.filterIsInstance<Assignment>().first { (it.value as? AddressOf)?.identifier?.nameInSource==listOf("main", "var_outside") }.value as AddressOf).identifier
+        assertThat(asmgen.asmSymbolName(scopedVarIdentScoped), equalTo("main.var_outside"))
+        assertThat(asmgen.asmVariableName(scopedVarIdentScoped), equalTo("main.var_outside"))
+    }
+
+    @Test
+    fun testSymbolNameFromLabelIdentifier() {
+        val program = createTestProgram()
+        val asmgen = createTestAsmGen(program)
+        val sub = program.entrypoint
+
+        // local label
+        val localLabelIdent = (sub.statements.filterIsInstance<Assignment>().first { (it.value as? AddressOf)?.identifier?.nameInSource==listOf("locallabel") }.value as AddressOf).identifier
+        assertThat(asmgen.asmSymbolName(localLabelIdent), equalTo("_locallabel"))
+        assertThat("as a variable it uses different naming rules (no underscore prefix)", asmgen.asmVariableName(localLabelIdent), equalTo("locallabel"))
+        val localLabelIdentScoped = (sub.statements.filterIsInstance<Assignment>().first { (it.value as? AddressOf)?.identifier?.nameInSource==listOf("main","start","locallabel") }.value as AddressOf).identifier
+        assertThat(asmgen.asmSymbolName(localLabelIdentScoped), equalTo("main.start._locallabel"))
+        assertThat("as a variable it uses different naming rules (no underscore prefix)", asmgen.asmVariableName(localLabelIdentScoped), equalTo("main.start.locallabel"))
+
+        // label from outer scope needs sope prefixes because it is outputted as a locally scoped symbol for the assembler
+        val scopedLabelIdent = (sub.statements.filterIsInstance<Assignment>().first { (it.value as? AddressOf)?.identifier?.nameInSource==listOf("label_outside") }.value as AddressOf).identifier
+        assertThat(asmgen.asmSymbolName(scopedLabelIdent), equalTo("main._label_outside"))
+        assertThat("as a variable it uses different naming rules (no underscore prefix)", asmgen.asmVariableName(scopedLabelIdent), equalTo("label_outside"))
+        val scopedLabelIdentScoped = (sub.statements.filterIsInstance<Assignment>().first { (it.value as? AddressOf)?.identifier?.nameInSource==listOf("main","label_outside") }.value as AddressOf).identifier
+        assertThat(asmgen.asmSymbolName(scopedLabelIdentScoped), equalTo("main._label_outside"))
+        assertThat("as a variable it uses different naming rules (no underscore prefix)", asmgen.asmVariableName(scopedLabelIdentScoped), equalTo("main.label_outside"))
+    }
+}

compiler/test/ModuleImporterTests.kt

@@ -0,0 +1,322 @@
+package prog8tests
+
+import kotlin.test.*
+import com.github.michaelbull.result.getErrorOrElse
+import com.github.michaelbull.result.getOrElse
+import org.hamcrest.MatcherAssert.assertThat
+import org.hamcrest.Matchers.*
+import org.hamcrest.core.Is
+import org.junit.jupiter.api.BeforeEach
+import org.junit.jupiter.api.Nested
+import org.junit.jupiter.api.Test
+import org.junit.jupiter.api.TestInstance
+import org.junit.jupiter.api.Disabled
+import prog8.ast.Program
+import prog8.compiler.IErrorReporter
+import prog8.compiler.ModuleImporter
+import prog8.parser.ParseError
+import prog8tests.helpers.*
+import kotlin.io.path.*
+
+
+@TestInstance(TestInstance.Lifecycle.PER_CLASS)
+class TestModuleImporter {
+    private val count = listOf("1st", "2nd", "3rd", "4th", "5th")
+
+    private lateinit var program: Program
+    @BeforeEach
+    fun beforeEach() {
+        program = Program("foo", DummyFunctions, DummyMemsizer)
+    }
+
+    private fun makeImporter(errors: IErrorReporter?, vararg searchIn: String): ModuleImporter {
+        return makeImporter(errors, searchIn.asList())
+    }
+
+    private fun makeImporter(errors: IErrorReporter? = null, searchIn: Iterable<String>) =
+        ModuleImporter(program, "blah", errors ?: ErrorReporterForTests(), searchIn.toList())
+
+    @Nested
+    inner class Constructor {
+
+        @Test
+        @Disabled("TODO: invalid entries in search list")
+        fun testInvalidEntriesInSearchList() {}
+
+        @Test
+        @Disabled("TODO: literal duplicates in search list")
+        fun testLiteralDuplicatesInSearchList() {}
+
+        @Test
+        @Disabled("TODO: factual duplicates in search list")
+        fun testFactualDuplicatesInSearchList() {}
+    }
+
+    @Nested
+    inner class ImportModule {
+
+        @Nested
+        inner class WithInvalidPath {
+            @Test
+            fun testNonexisting() {
+                val dirRel = assumeDirectory(".", workingDir.relativize(fixturesDir))
+                val importer = makeImporter(null, dirRel.invariantSeparatorsPathString)
+                val srcPathRel = assumeNotExists(dirRel, "i_do_not_exist")
+                val srcPathAbs = srcPathRel.absolute()
+                val error1 = importer.importModule(srcPathRel).getErrorOrElse { fail("should have import error") }
+                assertThat(
+                    ".file should be normalized",
+                    "${error1.file}", equalTo("${error1.file.normalize()}")
+                )
+                assertThat(
+                    ".file should point to specified path",
+                    error1.file.absolutePath, equalTo("${srcPathAbs.normalize()}")
+                )
+                assertThat(program.modules.size, equalTo(1))
+
+                val error2 = importer.importModule(srcPathAbs).getErrorOrElse { fail("should have import error") }
+                assertThat(
+                    ".file should be normalized",
+                    "${error2.file}", equalTo("${error2.file.normalize()}")
+                )
+                assertThat(
+                    ".file should point to specified path",
+                    error2.file.absolutePath, equalTo("${srcPathAbs.normalize()}")
+                )
+                assertThat(program.modules.size, equalTo(1))
+            }
+
+            @Test
+            fun testDirectory() {
+                val srcPathRel = assumeDirectory(workingDir.relativize(fixturesDir))
+                val srcPathAbs = srcPathRel.absolute()
+                val searchIn = Path(".", "$srcPathRel").invariantSeparatorsPathString
+                val importer = makeImporter(null, searchIn)
+
+                assertFailsWith<AccessDeniedException> { importer.importModule(srcPathRel) }
+                    .let {
+                        assertThat(
+                            ".file should be normalized",
+                            "${it.file}", equalTo("${it.file.normalize()}")
+                        )
+                        assertThat(
+                            ".file should point to specified path",
+                            it.file.absolutePath, equalTo("${srcPathAbs.normalize()}")
+                        )
+                    }
+                assertThat(program.modules.size, equalTo(1))
+
+                assertFailsWith<AccessDeniedException> { importer.importModule(srcPathAbs) }
+                    .let {
+                        assertThat(
+                            ".file should be normalized",
+                            "${it.file}", equalTo("${it.file.normalize()}")
+                        )
+                        assertThat(
+                            ".file should point to specified path",
+                            it.file.absolutePath, equalTo("${srcPathAbs.normalize()}")
+                        )
+                    }
+                assertThat(program.modules.size, equalTo(1))
+            }
+        }
+
+        @Nested
+        inner class WithValidPath {
+
+            @Test
+            fun testAbsolute() {
+                val searchIn = listOf(
+                    Path(".").div(workingDir.relativize(fixturesDir)), // we do want a dot "." in front
+                ).map { it.invariantSeparatorsPathString }
+                val importer = makeImporter(null, searchIn)
+                val fileName = "simple_main.p8"
+                val path = assumeReadableFile(searchIn[0], fileName)
+
+                val module = importer.importModule(path.absolute()).getOrElse { throw it }
+                assertThat(program.modules.size, equalTo(2))
+                assertContains(program.modules, module)
+                assertThat(module.program, equalTo(program))
+            }
+
+            @Test
+            fun testRelativeToWorkingDir() {
+                val searchIn = listOf(
+                    Path(".").div(workingDir.relativize(fixturesDir)), // we do want a dot "." in front
+                ).map { it.invariantSeparatorsPathString }
+                val importer = makeImporter(null, searchIn)
+                val fileName = "simple_main.p8"
+                val path = assumeReadableFile(searchIn[0], fileName)
+                assertThat("sanity check: path should NOT be absolute", path.isAbsolute, equalTo(false))
+
+                val module = importer.importModule(path).getOrElse { throw it }
+                assertThat(program.modules.size, equalTo(2))
+                assertContains(program.modules, module)
+                assertThat(module.program, equalTo(program))
+            }
+
+            @Test
+            fun testRelativeTo1stDirInSearchList() {
+                val searchIn = Path(".")
+                    .div(workingDir.relativize(fixturesDir))
+                    .invariantSeparatorsPathString
+                val importer = makeImporter(null, searchIn)
+                val fileName = "simple_main.p8"
+                val path = Path(".", fileName)
+                assumeReadableFile(searchIn, path)
+
+                val module = importer.importModule(path).getOrElse { throw it }
+                assertThat(program.modules.size, equalTo(2))
+                assertContains(program.modules, module)
+                assertThat(module.program, equalTo(program))
+            }
+
+            @Test
+            @Disabled("TODO: relative to 2nd in search list")
+            fun testRelativeTo2ndDirInSearchList() {}
+
+            @Test
+            @Disabled("TODO: ambiguous - 2 or more really different candidates")
+            fun testAmbiguousCandidates() {}
+
+            @Nested
+            inner class WithBadFile {
+                @Test
+                fun testWithSyntaxError() {
+                    val searchIn = assumeDirectory("./", workingDir.relativize(fixturesDir))
+                    val importer = makeImporter(null, searchIn.invariantSeparatorsPathString)
+                    val srcPath = assumeReadableFile(fixturesDir, "file_with_syntax_error.p8")
+
+                    val act = { importer.importModule(srcPath) }
+
+                    repeat(2) { n ->
+                        assertFailsWith<ParseError>(count[n] + " call") { act() }.let {
+                            assertThat(it.position.file, equalTo(srcPath.absolutePathString()))
+                            assertThat("line; should be 1-based", it.position.line, equalTo(2))
+                            assertThat("startCol; should be 0-based", it.position.startCol, equalTo(6))
+                            assertThat("endCol; should be 0-based", it.position.endCol, equalTo(6))
+                        }
+                        assertThat(program.modules.size, equalTo(1))
+                    }
+                }
+
+                @Test
+                fun testImportingFileWithSyntaxError_once() {
+                    doTestImportingFileWithSyntaxError(1)
+                }
+
+                @Test
+                @Disabled("TODO: module that imports faulty module should not be kept in Program.modules")
+                fun testImportingFileWithSyntaxError_twice() {
+                    doTestImportingFileWithSyntaxError(2)
+                }
+
+                private fun doTestImportingFileWithSyntaxError(repetitions: Int) {
+                    val searchIn = assumeDirectory("./", workingDir.relativize(fixturesDir))
+                    val importer = makeImporter(null, searchIn.invariantSeparatorsPathString)
+                    val importing = assumeReadableFile(fixturesDir, "import_file_with_syntax_error.p8")
+                    val imported = assumeReadableFile(fixturesDir, "file_with_syntax_error.p8")
+
+                    val act = { importer.importModule(importing) }
+
+                    repeat(repetitions) { n ->
+                        assertFailsWith<ParseError>(count[n] + " call") { act() }.let {
+                            assertThat(it.position.file, equalTo(imported.absolutePathString()))
+                            assertThat("line; should be 1-based", it.position.line, equalTo(2))
+                            assertThat("startCol; should be 0-based", it.position.startCol, equalTo(6))
+                            assertThat("endCol; should be 0-based", it.position.endCol, equalTo(6))
+                        }
+                        assertThat(program.modules.size, equalTo(2))
+                    }
+                }
+            }
+        }
+
+    }
+
+    @Nested
+    inner class ImportLibraryModule {
+        @Nested
+        inner class WithInvalidName {
+            @Test
+            fun testWithNonExistingName() {
+                val searchIn = assumeDirectory("./", workingDir.relativize(fixturesDir))
+                val errors = ErrorReporterForTests()
+                val importer = makeImporter(errors, searchIn.invariantSeparatorsPathString)
+                val filenameNoExt = assumeNotExists(fixturesDir, "i_do_not_exist").name
+                val filenameWithExt = assumeNotExists(fixturesDir, "i_do_not_exist.p8").name
+
+                repeat(2) { n ->
+                    val result = importer.importLibraryModule(filenameNoExt)
+                    assertThat(count[n] + " call / NO .p8 extension", result, Is(nullValue()))
+                    assertFalse(errors.noErrors(), count[n] + " call / NO .p8 extension")
+                    assertEquals(errors.errors.single(), "imported file not found: i_do_not_exist.p8")
+                    errors.report()
+                    assertThat(program.modules.size, equalTo(1))
+
+                    val result2 = importer.importLibraryModule(filenameWithExt)
+                    assertThat(count[n] + " call / with .p8 extension", result2, Is(nullValue()))
+                    assertFalse(importer.errors.noErrors(), count[n] + " call / with .p8 extension")
+                    assertEquals(errors.errors.single(), "imported file not found: i_do_not_exist.p8.p8")       // TODO don't duplicate the p8 extension in the import logic...
+                    errors.report()
+                    assertThat(program.modules.size, equalTo(1))
+                }
+            }
+        }
+
+        @Nested
+        inner class WithValidName {
+            @Nested
+            inner class WithBadFile {
+                @Test
+                fun testWithSyntaxError() {
+                    val searchIn = assumeDirectory("./", workingDir.relativize(fixturesDir))
+                    val importer = makeImporter(null, searchIn.invariantSeparatorsPathString)
+                    val srcPath = assumeReadableFile(fixturesDir, "file_with_syntax_error.p8")
+
+                    repeat(2) { n ->
+                        assertFailsWith<ParseError>(count[n] + " call")
+                            { importer.importLibraryModule(srcPath.nameWithoutExtension) }.let {
+                                assertThat(it.position.file, equalTo(srcPath.absolutePathString()))
+                                assertThat("line; should be 1-based", it.position.line, equalTo(2))
+                                assertThat("startCol; should be 0-based", it.position.startCol, equalTo(6))
+                                assertThat("endCol; should be 0-based", it.position.endCol, equalTo(6))
+                            }
+                        assertThat(program.modules.size, equalTo(1))
+                    }
+                }
+
+
+                private fun doTestImportingFileWithSyntaxError(repetitions: Int) {
+                    val searchIn = assumeDirectory("./", workingDir.relativize(fixturesDir))
+                    val importer = makeImporter(null, searchIn.invariantSeparatorsPathString)
+                    val importing = assumeReadableFile(fixturesDir, "import_file_with_syntax_error.p8")
+                    val imported = assumeReadableFile(fixturesDir, "file_with_syntax_error.p8")
+
+                    val act = { importer.importLibraryModule(importing.nameWithoutExtension) }
+
+                    repeat(repetitions) { n ->
+                        assertFailsWith<ParseError>(count[n] + " call") { act() }.let {
+                            assertThat(it.position.file, equalTo(imported.normalize().absolutePathString()))
+                            assertThat("line; should be 1-based", it.position.line, equalTo(2))
+                            assertThat("startCol; should be 0-based", it.position.startCol, equalTo(6))
+                            assertThat("endCol; should be 0-based", it.position.endCol, equalTo(6))
+                        }
+                        assertThat(program.modules.size, equalTo(2))
+                    }
+                }
+
+                @Test
+                fun testImportingFileWithSyntaxError_once() {
+                    doTestImportingFileWithSyntaxError(1)
+                }
+
+                @Test
+                @Disabled("TODO: module that imports faulty module should not be kept in Program.modules")
+                fun testImportingFileWithSyntaxError_twice() {
+                    doTestImportingFileWithSyntaxError(2)
+                }
+            }
+        }
+    }
+}

compiler/test/TestCompilerOnCharLit.kt

@@ -0,0 +1,120 @@
+package prog8tests
+
+import org.junit.jupiter.api.Test
+import org.junit.jupiter.api.TestInstance
+import prog8.ast.IFunctionCall
+import prog8.ast.base.DataType
+import prog8.ast.base.VarDeclType
+import prog8.ast.expressions.IdentifierReference
+import prog8.ast.expressions.NumericLiteralValue
+import prog8.compiler.target.Cx16Target
+import prog8tests.helpers.assertSuccess
+import prog8tests.helpers.compileText
+import kotlin.test.assertEquals
+import kotlin.test.assertIs
+
+
+/**
+ * ATTENTION: this is just kludge!
+ * They are not really unit tests, but rather tests of the whole process,
+ * from source file loading all the way through to running 64tass.
+ */
+@TestInstance(TestInstance.Lifecycle.PER_CLASS)
+class TestCompilerOnCharLit {
+
+    @Test
+    fun testCharLitAsRomsubArg() {
+        val platform = Cx16Target
+        val result = compileText(platform, false, """
+            main {
+                romsub ${"$"}FFD2 = chrout(ubyte ch @ A)
+                sub start() {
+                    chrout('\n')
+                }
+            }
+        """).assertSuccess()
+
+        val program = result.programAst
+        val startSub = program.entrypoint
+        val funCall = startSub.statements.filterIsInstance<IFunctionCall>()[0]
+
+        assertIs<NumericLiteralValue>(funCall.args[0],
+            "char literal should have been replaced by ubyte literal")
+        val arg = funCall.args[0] as NumericLiteralValue
+        assertEquals(DataType.UBYTE, arg.type)
+        assertEquals(platform.encodeString("\n", false)[0], arg.number.toShort()) // TODO: short/int/UBYTE - which should it be?
+    }
+
+    @Test
+    fun testCharVarAsRomsubArg() {
+        val platform = Cx16Target
+        val result = compileText(platform, false, """
+            main {
+                romsub ${"$"}FFD2 = chrout(ubyte ch @ A)
+                sub start() {
+                    ubyte ch = '\n'
+                    chrout(ch)
+                }
+            }
+        """).assertSuccess()
+
+        val program = result.programAst
+        val startSub = program.entrypoint
+        val funCall = startSub.statements.filterIsInstance<IFunctionCall>()[0]
+
+        assertIs<IdentifierReference>(funCall.args[0])
+        val arg = funCall.args[0] as IdentifierReference
+        val decl = arg.targetVarDecl(program)!!
+        assertEquals(VarDeclType.VAR, decl.type)
+        assertEquals(DataType.UBYTE, decl.datatype)
+
+        // TODO: assertIs<CharLiteral>(decl.value,
+        //          "char literals should be kept until code gen")
+        //       val initializerValue = decl.value as CharLiteral
+        //       assertEquals('\n', (initializerValue as CharLiteral).value)
+
+        assertIs<NumericLiteralValue>(decl.value,
+            "char literal should have been replaced by ubyte literal")
+        val initializerValue = decl.value as NumericLiteralValue
+        assertEquals(DataType.UBYTE, initializerValue.type)
+        assertEquals(platform.encodeString("\n", false)[0], initializerValue.number.toShort()) // TODO: short/int/UBYTE - which should it be?
+    }
+
+    @Test
+    fun testCharConstAsRomsubArg() {
+        val platform = Cx16Target
+        val result = compileText(platform, false, """
+            main {
+                romsub ${"$"}FFD2 = chrout(ubyte ch @ A)
+                sub start() {
+                    const ubyte ch = '\n'
+                    chrout(ch)
+                }
+            }
+        """).assertSuccess()
+
+        val program = result.programAst
+        val startSub = program.entrypoint
+        val funCall = startSub.statements.filterIsInstance<IFunctionCall>()[0]
+
+        // Now, both is ok for the arg: a) still the IdRef or b) replaced by numeric literal
+        when (val arg = funCall.args[0]) {
+            is IdentifierReference -> {
+                val decl = arg.targetVarDecl(program)!!
+                assertEquals(VarDeclType.CONST, decl.type)
+                assertEquals(DataType.UBYTE, decl.datatype)
+                assertEquals(
+                    platform.encodeString("\n", false)[0],
+                    (decl.value as NumericLiteralValue).number.toShort()) // TODO: short/int/UBYTE - which should it be?
+            }
+            is NumericLiteralValue -> {
+                assertEquals(
+                    platform.encodeString("\n", false)[0],
+                    arg.number.toShort()) // TODO: short/int/UBYTE - which should it be?
+            }
+            else -> assertIs<IdentifierReference>(funCall.args[0]) // make test fail
+        }
+    }
+
+}
+

compiler/test/TestCompilerOnExamples.kt

@@ -0,0 +1,120 @@
+package prog8tests
+
+import org.junit.jupiter.api.DynamicTest
+import org.junit.jupiter.api.DynamicTest.dynamicTest
+import org.junit.jupiter.api.TestFactory
+import org.junit.jupiter.api.TestInstance
+import prog8.compiler.compileProgram
+import prog8.compiler.target.C64Target
+import prog8.compiler.target.Cx16Target
+import prog8.compiler.target.ICompilationTarget
+import prog8tests.helpers.*
+import kotlin.io.path.absolute
+import kotlin.io.path.exists
+
+
+/**
+ * ATTENTION: this is just kludge!
+ * They are not really unit tests, but rather tests of the whole process,
+ * from source file loading all the way through to running 64tass.
+ */
+//@Disabled("to save some time")
+@TestInstance(TestInstance.Lifecycle.PER_CLASS)
+class TestCompilerOnExamples {
+    private val examplesDir = assumeDirectory(workingDir, "../examples")
+
+    private fun makeDynamicCompilerTest(name: String, platform: ICompilationTarget, optimize: Boolean) : DynamicTest {
+        val searchIn = mutableListOf(examplesDir)
+        if (platform == Cx16Target) {
+            searchIn.add(0, assumeDirectory(examplesDir, "cx16"))
+        }
+        val filepath = searchIn
+            .map { it.resolve("$name.p8") }
+            .map { it.normalize().absolute() }
+            .map { workingDir.relativize(it) }
+            .first { it.exists() }
+        val displayName = "${examplesDir.relativize(filepath.absolute())}: ${platform.name}, optimize=$optimize"
+        return dynamicTest(displayName) {
+            compileProgram(
+                filepath,
+                optimize,
+                writeAssembly = true,
+                slowCodegenWarnings = false,
+                compilationTarget = platform.name,
+                libdirs = listOf(),
+                outputDir
+            ).assertSuccess("; $displayName")
+        }
+    }
+
+    @TestFactory
+//    @Disabled
+    fun bothCx16AndC64() = mapCombinations(
+        dim1 = listOf(
+            "animals",
+            "balls",
+            "cube3d",
+            "cube3d-float",
+            "cube3d-gfx",
+            "cxlogo",
+            "dirlist",
+            "fibonacci",
+            "line-circle-gfx",
+            "line-circle-txt",
+            "mandelbrot",
+            "mandelbrot-gfx",
+            "numbergame",
+            "primes",
+            "rasterbars",
+            "screencodes",
+            "sorting",
+            "swirl",
+            "swirl-float",
+            "tehtriz",
+            "textelite",
+        ),
+        dim2 = listOf(Cx16Target, C64Target),
+        dim3 = listOf(false, true),
+        combine3 = ::makeDynamicCompilerTest
+    )
+
+    @TestFactory
+//    @Disabled
+    fun onlyC64() = mapCombinations(
+        dim1 = listOf(
+            "balloonflight",
+            "bdmusic",
+            "bdmusic-irq",
+            "charset",
+            "cube3d-sprites",
+            "plasma",
+            "sprites",
+            "turtle-gfx",
+            "wizzine",
+        ),
+        dim2 = listOf(C64Target),
+        dim3 = listOf(false, true),
+        combine3 = ::makeDynamicCompilerTest
+    )
+
+    @TestFactory
+//    @Disabled
+    fun onlyCx16() = mapCombinations(
+        dim1 = listOf(
+            "vtui/testvtui",
+            "amiga",
+            "bobs",
+            "cobramk3-gfx",
+            "colorbars",
+            "datetime",
+            "highresbitmap",
+            "kefrenbars",
+            "mandelbrot-gfx-colors",
+            "multipalette",
+            "testgfx2",
+        ),
+        dim2 = listOf(Cx16Target),
+        dim3 = listOf(false, true),
+        combine3 = ::makeDynamicCompilerTest
+    )
+}

compiler/test/TestCompilerOnImportsAndIncludes.kt

@@ -0,0 +1,149 @@
+package prog8tests
+
+import org.junit.jupiter.api.*
+import org.junit.jupiter.api.DynamicTest.dynamicTest
+import prog8.ast.expressions.AddressOf
+import prog8.ast.expressions.IdentifierReference
+import prog8.ast.expressions.StringLiteralValue
+import prog8.ast.statements.FunctionCallStatement
+import prog8.ast.statements.Label
+import prog8.compiler.target.Cx16Target
+import prog8tests.helpers.*
+import kotlin.io.path.name
+import kotlin.test.assertEquals
+import kotlin.test.assertNotEquals
+
+
+/**
+ * ATTENTION: this is just kludge!
+ * They are not really unit tests, but rather tests of the whole process,
+ * from source file loading all the way through to running 64tass.
+ */
+@TestInstance(TestInstance.Lifecycle.PER_CLASS)
+class TestCompilerOnImportsAndIncludes {
+
+    @Nested
+    inner class Import {
+
+        @Test
+        fun testImportFromSameFolder() {
+            val filepath = assumeReadableFile(fixturesDir, "importFromSameFolder.p8")
+            assumeReadableFile(fixturesDir, "foo_bar.p8")
+
+            val platform = Cx16Target
+            val result = compileFile(platform, optimize = false, fixturesDir, filepath.name)
+                .assertSuccess()
+
+            val program = result.programAst
+            val startSub = program.entrypoint
+            val strLits = startSub.statements
+                .filterIsInstance<FunctionCallStatement>()
+                .map { it.args[0] as IdentifierReference }
+                .map { it.targetVarDecl(program)!!.value as StringLiteralValue }
+
+            assertEquals("main.bar", strLits[0].value)
+            assertEquals("foo.bar", strLits[1].value)
+            assertEquals("main", strLits[0].definingScope.name)
+            assertEquals("foo", strLits[1].definingScope.name)
+        }
+
+        @Test
+        @Disabled("TODO: why would we not accept string literals as argument to %import?")
+        fun testImportFromSameFolder_strLit() {
+            val filepath = assumeReadableFile(fixturesDir,"importFromSameFolder_strLit.p8")
+            val imported = assumeReadableFile(fixturesDir, "foo_bar.p8")
+
+            val platform = Cx16Target
+            val result = compileFile(platform, optimize = false, fixturesDir, filepath.name)
+                .assertSuccess()
+
+            val program = result.programAst
+            val startSub = program.entrypoint
+            val strLits = startSub.statements
+                .filterIsInstance<FunctionCallStatement>()
+                .map { it.args[0] as IdentifierReference }
+                .map { it.targetVarDecl(program)!!.value as StringLiteralValue }
+
+            assertEquals("main.bar", strLits[0].value)
+            assertEquals("foo.bar", strLits[1].value)
+            assertEquals("main", strLits[0].definingScope.name)
+            assertEquals("foo", strLits[1].definingScope.name)
+        }
+    }
+
+    @Nested
+    inner class AsmInclude {
+        @Test
+        fun testAsmIncludeFromSameFolder() {
+            val filepath = assumeReadableFile(fixturesDir, "asmIncludeFromSameFolder.p8")
+            assumeReadableFile(fixturesDir, "foo_bar.asm")
+
+            val platform = Cx16Target
+            val result = compileFile(platform, optimize = false, fixturesDir, filepath.name)
+                .assertSuccess()
+
+            val program = result.programAst
+            val startSub = program.entrypoint
+            val args = startSub.statements
+                .filterIsInstance<FunctionCallStatement>()
+                .map { it.args[0] }
+
+            val str0 = (args[0] as IdentifierReference).targetVarDecl(program)!!.value as StringLiteralValue
+            assertEquals("main.bar", str0.value)
+            assertEquals("main", str0.definingScope.name)
+
+            val id1 = (args[1] as AddressOf).identifier
+            val lbl1 = id1.targetStatement(program) as Label
+            assertEquals("foo_bar", lbl1.name)
+            assertEquals("start", lbl1.definingScope.name)
+        }
+    }
+
+    @Nested
+    inner class Asmbinary {
+        @Test
+        fun testAsmbinaryDirectiveWithNonExistingFile() {
+            val p8Path = assumeReadableFile(fixturesDir, "asmBinaryNonExisting.p8")
+            assumeNotExists(fixturesDir, "i_do_not_exist.bin")
+
+            compileFile(Cx16Target, false, p8Path.parent, p8Path.name, outputDir)
+                .assertFailure()
+        }
+
+        @Test
+        fun testAsmbinaryDirectiveWithNonReadableFile() {
+            val p8Path = assumeReadableFile(fixturesDir, "asmBinaryNonReadable.p8")
+            assumeDirectory(fixturesDir, "subFolder")
+
+            compileFile(Cx16Target, false, p8Path.parent, p8Path.name, outputDir)
+                .assertFailure()
+        }
+
+        @TestFactory
+        fun asmbinaryDirectiveWithExistingBinFile(): Iterable<DynamicTest> =
+            listOf(
+                Triple("same ", "asmBinaryFromSameFolder.p8", "do_nothing1.bin"),
+                Triple("sub", "asmBinaryFromSubFolder.p8", "subFolder/do_nothing2.bin"),
+            ).map {
+                val (where, p8Str, binStr) = it
+                dynamicTest("%asmbinary from ${where}folder") {
+                    val p8Path = assumeReadableFile(fixturesDir, p8Str)
+                    val binPath = assumeReadableFile(fixturesDir, binStr)
+                    assertNotEquals( // the bug we're testing for (#54) was hidden if outputDir == workinDir
+                        workingDir.normalize().toAbsolutePath(),
+                        outputDir.normalize().toAbsolutePath(),
+                        "sanity check: workingDir and outputDir should not be the same folder"
+                    )
+
+                    compileFile(Cx16Target, false, p8Path.parent, p8Path.name, outputDir)
+                        .assertSuccess(
+                            "argument to assembler directive .binary " +
+                                    "should be relative to the generated .asm file (in output dir), " +
+                                    "NOT relative to .p8 neither current working dir"
+                        )
+                }
+            }
+
+    }
+
+}

compiler/test/TestCompilerOnRanges.kt

@@ -0,0 +1,264 @@
+package prog8tests
+
+import org.junit.jupiter.api.DynamicTest.dynamicTest
+import org.junit.jupiter.api.Test
+import org.junit.jupiter.api.TestFactory
+import org.junit.jupiter.api.TestInstance
+import prog8.ast.base.DataType
+import prog8.ast.expressions.*
+import prog8.ast.statements.ForLoop
+import prog8.ast.statements.Subroutine
+import prog8.ast.statements.VarDecl
+import prog8.compiler.astprocessing.size
+import prog8.compiler.astprocessing.toConstantIntegerRange
+import prog8.compiler.target.C64Target
+import prog8.compiler.target.Cx16Target
+import prog8tests.helpers.assertFailure
+import prog8tests.helpers.assertSuccess
+import prog8tests.helpers.compileText
+import prog8tests.helpers.mapCombinations
+import kotlin.test.assertEquals
+
+
+/**
+ * ATTENTION: this is just kludge!
+ * They are not really unit tests, but rather tests of the whole process,
+ * from source file loading all the way through to running 64tass.
+ */
+@TestInstance(TestInstance.Lifecycle.PER_CLASS)
+class TestCompilerOnRanges {
+
+    @Test
+    fun testUByteArrayInitializerWithRange_char_to_char() {
+        val platform = Cx16Target
+        val result = compileText(platform, true, """
+            main {
+                sub start() {
+                    ubyte[] cs = @'a' to 'z' ; values are computed at compile time 
+                    cs[0] = 23 ; keep optimizer from removing it
+                }
+            }
+        """).assertSuccess()
+
+        val program = result.programAst
+        val startSub = program.entrypoint
+        val decl = startSub
+            .statements.filterIsInstance<VarDecl>()[0]
+        val rhsValues = (decl.value as ArrayLiteralValue)
+            .value // Array<Expression>
+            .map { (it as NumericLiteralValue).number.toInt() }
+        val expectedStart = platform.encodeString("a", true)[0].toInt()
+        val expectedEnd = platform.encodeString("z", false)[0].toInt()
+        val expectedStr = "$expectedStart .. $expectedEnd"
+
+        val actualStr = "${rhsValues.first()} .. ${rhsValues.last()}"
+        assertEquals(expectedStr, actualStr,".first .. .last")
+        assertEquals(expectedEnd - expectedStart + 1, rhsValues.last() - rhsValues.first() + 1, "rangeExpr.size()")
+    }
+
+    @Test
+    fun testFloatArrayInitializerWithRange_char_to_char() {
+        val platform = C64Target
+        val result = compileText(platform, optimize = false, """
+            %option enable_floats
+            main {
+                sub start() {
+                    float[] cs = 'a' to 'z' ; values are computed at compile time 
+                    cs[0] = 23 ; keep optimizer from removing it
+                }
+            }
+        """).assertSuccess()
+
+        val program = result.programAst
+        val startSub = program.entrypoint
+        val decl = startSub
+            .statements.filterIsInstance<VarDecl>()[0]
+        val rhsValues = (decl.value as ArrayLiteralValue)
+            .value // Array<Expression>
+            .map { (it as NumericLiteralValue).number.toInt() }
+        val expectedStart = platform.encodeString("a", false)[0].toInt()
+        val expectedEnd = platform.encodeString("z", false)[0].toInt()
+        val expectedStr = "$expectedStart .. $expectedEnd"
+
+        val actualStr = "${rhsValues.first()} .. ${rhsValues.last()}"
+        assertEquals(expectedStr, actualStr,".first .. .last")
+        assertEquals(expectedEnd - expectedStart + 1, rhsValues.size, "rangeExpr.size()")
+    }
+
+    fun Subroutine.decl(varName: String): VarDecl {
+        return statements.filterIsInstance<VarDecl>()
+            .first { it.name == varName }
+    }
+    inline fun <reified T : Expression> VarDecl.rhs() : T {
+        return value as T
+    }
+    inline fun <reified T : Expression> ArrayLiteralValue.elements() : List<T> {
+        return value.map { it as T }
+    }
+
+    fun <N : Number> assertEndpoints(expFirst: N, expLast: N, actual: Iterable<N>, msg: String = ".first .. .last") {
+        val expectedStr = "$expFirst .. $expLast"
+        val actualStr = "${actual.first()} .. ${actual.last()}"
+        assertEquals(expectedStr, actualStr,".first .. .last")
+    }
+
+
+    @TestFactory
+    fun floatArrayInitializerWithRange() = mapCombinations(
+        dim1 = listOf("", "42", "41"),                 // sizeInDecl
+        dim2 = listOf("%option enable_floats", ""),    // optEnableFloats
+        dim3 = listOf(Cx16Target, C64Target),          // platform
+        dim4 = listOf(false, true),                    // optimize
+        combine4 = { sizeInDecl, optEnableFloats, platform, optimize ->
+            val displayName =
+                "test failed for: " +
+                when (sizeInDecl) {
+                    "" -> "no"
+                    "42" -> "correct"
+                    else -> "wrong"
+                } + " array size given" +
+                ", " + (if (optEnableFloats == "") "without" else "with") + " %option enable_floats" +
+                ", ${platform.name}, optimize: $optimize"
+            dynamicTest(displayName) {
+                val result = compileText(platform, optimize, """
+                    $optEnableFloats
+                    main {
+                        sub start() {
+                            float[$sizeInDecl] cs = 1 to 42 ; values are computed at compile time 
+                            cs[0] = 23 ; keep optimizer from removing it
+                        }
+                    }
+                """)
+                if (optEnableFloats != "" && (sizeInDecl=="" || sizeInDecl=="42"))
+                    result.assertSuccess()
+                else
+                    result.assertFailure()
+            }
+        }
+    )
+
+    @Test
+    fun testForLoopWithRange_char_to_char() {
+        val platform = Cx16Target
+        val result = compileText(platform, optimize = true, """
+            main {
+                sub start() {
+                    ubyte i
+                    for i in @'a' to 'f' {
+                        i += i ; keep optimizer from removing it
+                    }
+                }
+            }
+        """).assertSuccess()
+
+        val program = result.programAst
+        val startSub = program.entrypoint
+        val iterable = startSub
+            .statements.filterIsInstance<ForLoop>()
+            .map { it.iterable }[0]
+        val rangeExpr = iterable as RangeExpr
+
+        val expectedStart = platform.encodeString("a", true)[0].toInt()
+        val expectedEnd = platform.encodeString("f", false)[0].toInt()
+        val expectedStr = "$expectedStart .. $expectedEnd"
+
+        val intProgression = rangeExpr.toConstantIntegerRange(platform)
+        val actualStr = "${intProgression?.first} .. ${intProgression?.last}"
+        assertEquals(expectedStr, actualStr,".first .. .last")
+        assertEquals(expectedEnd - expectedStart + 1, rangeExpr.size(platform), "rangeExpr.size()")
+    }
+
+    @Test
+    fun testForLoopWithRange_bool_to_bool() {
+        val platform = Cx16Target
+        val result = compileText(platform, optimize = true, """
+            main {
+                sub start() {
+                    ubyte i
+                    for i in false to true {
+                        i += i ; keep optimizer from removing it
+                    }
+                }
+            }
+        """).assertSuccess()
+
+        val program = result.programAst
+        val startSub = program.entrypoint
+        val rangeExpr = startSub
+            .statements.filterIsInstance<ForLoop>()
+            .map { it.iterable }
+            .filterIsInstance<RangeExpr>()[0]
+
+        assertEquals(2, rangeExpr.size(platform))
+        val intProgression = rangeExpr.toConstantIntegerRange(platform)
+        assertEquals(0, intProgression?.first)
+        assertEquals(1, intProgression?.last)
+    }
+
+    @Test
+    fun testForLoopWithRange_ubyte_to_ubyte() {
+        val platform = Cx16Target
+        val result = compileText(platform, optimize = true, """
+            main {
+                sub start() {
+                    ubyte i
+                    for i in 1 to 9 {
+                        i += i ; keep optimizer from removing it
+                    }
+                }
+            }
+        """).assertSuccess()
+
+        val program = result.programAst
+        val startSub = program.entrypoint
+        val rangeExpr = startSub
+            .statements.filterIsInstance<ForLoop>()
+            .map { it.iterable }
+            .filterIsInstance<RangeExpr>()[0]
+
+        assertEquals(9, rangeExpr.size(platform))
+        val intProgression = rangeExpr.toConstantIntegerRange(platform)
+        assertEquals(1, intProgression?.first)
+        assertEquals(9, intProgression?.last)
+    }
+
+    @Test
+    fun testForLoopWithRange_str_downto_str() {
+        compileText(Cx16Target, true, """
+            main {
+                sub start() {
+                    ubyte i
+                    for i in "start" downto "end" {
+                        i += i ; keep optimizer from removing it
+                    }
+                }
+            }
+        """).assertFailure()
+        //TODO("test exact compile error(s)")
+    }
+
+    @Test
+    fun testForLoopWithIterable_str() {
+        val result = compileText(Cx16Target, false, """
+            main {
+                sub start() {
+                    ubyte i
+                    for i in "something" {
+                        i += i ; keep optimizer from removing it
+                    }
+                }
+            }
+        """).assertSuccess()
+
+        val program = result.programAst
+        val startSub = program.entrypoint
+        val iterable = startSub
+            .statements.filterIsInstance<ForLoop>()
+            .map { it.iterable }
+            .filterIsInstance<IdentifierReference>()[0]
+
+        assertEquals(DataType.STR, iterable.inferType(program).getOr(DataType.UNDEFINED))
+    }
+
+}
+