version 3.2

forever loop is gone (use repeat without iteration count).
struct literal is now same as array literal [...] to avoid parsing ambiguity with scope blocks.

.travis.yml

@@ -4,8 +4,8 @@ sudo: false
 # dist: xenial
 
 before_install:
-  - chmod +x gradlew
+  - chmod +x ./gradlew
 
 script:
-  - gradle test
+  - ./gradlew test
 

README.md

@@ -18,7 +18,7 @@ which aims to provide many conveniences over raw assembly code (even when using
 - modularity, symbol scoping, subroutines
 - various data types other than just bytes (16-bit words, floats, strings)
 - automatic variable allocations, automatic string and array variables and string sharing
-- subroutines with a input- and output parameter signature
+- subroutines with an input- and output parameter signature
 - constant folding in expressions
 - conditional branches
 - 'when' statement to provide a concise jump table alternative to if/elseif chains
@@ -77,7 +77,7 @@ This code calculates prime numbers using the Sieve of Eratosthenes algorithm::
 
             c64scr.print("prime numbers up to 255:\n\n")
             ubyte amount=0
-            while true {
+            repeat {
                 ubyte prime = find_next_prime()
                 if prime==0
                     break

compiler/build.gradle

@@ -1,11 +1,11 @@
 buildscript {
     dependencies {
-        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:1.3.72"
+        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:1.4.0"
     }
 }
 
 plugins {
-    // id "org.jetbrains.kotlin.jvm" version "1.3.72"
+    // id "org.jetbrains.kotlin.jvm" version "1.4.0"
     id 'application'
     id 'org.jetbrains.dokka' version "0.9.18"
     id 'com.github.johnrengelman.shadow' version '5.2.0'
@@ -110,3 +110,7 @@ dokka {
     outputFormat = 'html'
     outputDirectory = "$buildDir/kdoc"
 }
+
+task wrapper(type: Wrapper) {
+    gradleVersion = '6.1.1'
+}

compiler/res/prog8lib/c64floats.asm

@@ -201,6 +201,16 @@ pop_float_fac1	.proc
 		jmp  MOVFM
 		.pend
 
+pop_float_fac2	.proc
+		; -- pops float from stack into FAC2
+		lda  #<fmath_float1
+		ldy  #>fmath_float1
+		jsr  pop_float
+		lda  #<fmath_float1
+		ldy  #>fmath_float1
+		jmp  CONUPK
+		.pend
+
 pop_float_to_indexed_var	.proc
 		; -- pop the float on the stack, to the memory in the array at A/Y indexed by the byte on stack
 		sta  c64.SCRATCH_ZPWORD1
@@ -215,23 +225,13 @@ pop_float_to_indexed_var	.proc
 copy_float	.proc
 		; -- copies the 5 bytes of the mflt value pointed to by SCRATCH_ZPWORD1,
 		;    into the 5 bytes pointed to by A/Y.  Clobbers A,Y.
-		sta  c64.SCRATCH_ZPWORD2
-		sty  c64.SCRATCH_ZPWORD2+1
-		ldy  #0
-		lda  (c64.SCRATCH_ZPWORD1),y
-		sta  (c64.SCRATCH_ZPWORD2),y
-		iny
-		lda  (c64.SCRATCH_ZPWORD1),y
-		sta  (c64.SCRATCH_ZPWORD2),y
-		iny
-		lda  (c64.SCRATCH_ZPWORD1),y
-		sta  (c64.SCRATCH_ZPWORD2),y
-		iny
-		lda  (c64.SCRATCH_ZPWORD1),y
-		sta  (c64.SCRATCH_ZPWORD2),y
-		iny
-		lda  (c64.SCRATCH_ZPWORD1),y
-		sta  (c64.SCRATCH_ZPWORD2),y
+		sta  _target+1
+		sty  _target+2
+		ldy  #4
+_loop		lda  (c64.SCRATCH_ZPWORD1),y
+_target		sta  $ffff,y			; modified
+		dey
+		bpl  _loop
 		rts
 		.pend
 
@@ -772,7 +772,6 @@ set_array_float		.proc
 		asl  a
 		clc
 		adc  c64.ESTACK_LO,x
-		clc
 		adc  c64.SCRATCH_ZPWORD2
 		ldy  c64.SCRATCH_ZPWORD2+1
 		bcc  +
@@ -781,3 +780,18 @@ set_array_float		.proc
 			; -- copies the 5 bytes of the mflt value pointed to by SCRATCH_ZPWORD1,
 			;    into the 5 bytes pointed to by A/Y.  Clobbers A,Y.
 		.pend
+
+
+swap_floats	.proc
+		; -- swap floats pointed to by SCRATCH_ZPWORD1, SCRATCH_ZPWORD2
+		ldy  #4
+-               lda  (c64.SCRATCH_ZPWORD1),y
+		pha
+		lda  (c64.SCRATCH_ZPWORD2),y
+		sta  (c64.SCRATCH_ZPWORD1),y
+		pla
+		sta  (c64.SCRATCH_ZPWORD2),y
+		dey
+		bpl  -
+		rts
+		.pend

compiler/res/prog8lib/math.asm

@@ -52,6 +52,7 @@ multiply_words	.proc
 	; -- multiply two 16-bit words into a 32-bit result  (signed and unsigned)
 	;      input: A/Y = first 16-bit number, c64.SCRATCH_ZPWORD1 in ZP = second 16-bit number
 	;      output: multiply_words.result  4-bytes/32-bits product, LSB order (low-to-high)
+	;      clobbers: A
 
 		sta  c64.SCRATCH_ZPWORD2
 		sty  c64.SCRATCH_ZPWORD2+1

compiler/res/prog8lib/prog8lib.asm

@@ -36,13 +36,26 @@ init_system	.proc
 		.pend
 
 
-read_byte_from_address	.proc
+read_byte_from_address_on_stack	.proc
 	; -- read the byte from the memory address on the top of the stack, return in A (stack remains unchanged)
 		lda  c64.ESTACK_LO+1,x
 		ldy  c64.ESTACK_HI+1,x
-		sta  (+) +1
-		sty  (+) +2
-+		lda  $ffff		; modified
+		sta  c64.SCRATCH_ZPWORD2
+		sty  c64.SCRATCH_ZPWORD2+1
+		ldy  #0
+		lda  (c64.SCRATCH_ZPWORD2),y
+		rts
+		.pend
+
+
+write_byte_to_address_on_stack	.proc
+	; -- write the byte in A to the memory address on the top of the stack (stack remains unchanged)
+		ldy  c64.ESTACK_LO+1,x
+		sty  c64.SCRATCH_ZPWORD2
+		ldy  c64.ESTACK_HI+1,x
+		sty  c64.SCRATCH_ZPWORD2+1
+		ldy  #0
+		sta  (c64.SCRATCH_ZPWORD2),y
 		rts
 		.pend
 
@@ -330,9 +343,7 @@ mul_word	.proc
 		sta  c64.SCRATCH_ZPWORD1+1
 		lda  c64.ESTACK_LO+1,x
 		ldy  c64.ESTACK_HI+1,x
-		stx  c64.SCRATCH_ZPREGX
 		jsr  math.multiply_words
-		ldx  c64.SCRATCH_ZPREGX
 		lda  math.multiply_words.result
 		sta  c64.ESTACK_LO+1,x
 		lda  math.multiply_words.result+1
@@ -2079,7 +2090,7 @@ ror2_array_uw	.proc
 +		rts
 		.pend
 
-		
+
 strcpy		.proc
 		; copy a string (0-terminated) from A/Y to (ZPWORD1)
 		; it is assumed the target string is large enough.
@@ -2092,8 +2103,8 @@ strcpy		.proc
 		bne  -
 		rts
 		.pend
-		
-		
+
+
 func_leftstr	.proc
 		; leftstr(source, target, length) with params on stack
 		inx
@@ -2175,12 +2186,12 @@ func_substr	.proc
 		lda  c64.ESTACK_LO,x	; start
 		sta  c64.SCRATCH_ZPB1
 		inx
-		lda  c64.ESTACK_LO,x	
+		lda  c64.ESTACK_LO,x
 		sta  c64.SCRATCH_ZPWORD2
 		lda  c64.ESTACK_HI,x
 		sta  c64.SCRATCH_ZPWORD2+1
 		inx
-		lda  c64.ESTACK_LO,x	
+		lda  c64.ESTACK_LO,x
 		sta  c64.SCRATCH_ZPWORD1
 		lda  c64.ESTACK_HI,x
 		sta  c64.SCRATCH_ZPWORD1+1

compiler/res/version.txt

@@ -1 +1 @@
-2.2
+3.2

compiler/src/prog8/ast/AstToSourceCode.kt

@@ -287,12 +287,17 @@ class AstToSourceCode(val output: (text: String) -> Unit, val program: Program):
     }
 
     override fun visit(assignment: Assignment) {
-        assignment.target.accept(this)
-        if (assignment.aug_op != null && assignment.aug_op != "setvalue")
-            output(" ${assignment.aug_op} ")
-        else
+        val binExpr = assignment.value as? BinaryExpression
+        if(binExpr!=null && binExpr.left isSameAs assignment.target) {
+            // we only support the inplace assignments of the form A = A <operator> <value>
+            assignment.target.accept(this)
+            output(" ${binExpr.operator}= ")
+            binExpr.right.accept(this)
+        } else {
+            assignment.target.accept(this)
             output(" = ")
-        assignment.value.accept(this)
+            assignment.value.accept(this)
+        }
     }
 
     override fun visit(postIncrDecr: PostIncrDecr) {
@@ -300,20 +305,13 @@ class AstToSourceCode(val output: (text: String) -> Unit, val program: Program):
         output(postIncrDecr.operator)
     }
 
-    override fun visit(contStmt: Continue) {
-        output("continue")
-    }
-
     override fun visit(breakStmt: Break) {
         output("break")
     }
 
     override fun visit(forLoop: ForLoop) {
         output("for ")
-        if(forLoop.loopRegister!=null)
-            output(forLoop.loopRegister.toString())
-        else
-            forLoop.loopVar!!.accept(this)
+        forLoop.loopVar.accept(this)
         output(" in ")
         forLoop.iterable.accept(this)
         output(" ")
@@ -327,16 +325,18 @@ class AstToSourceCode(val output: (text: String) -> Unit, val program: Program):
         whileLoop.body.accept(this)
     }
 
-    override fun visit(foreverLoop: ForeverLoop) {
-        output("forever ")
-        foreverLoop.body.accept(this)
-    }
-
     override fun visit(repeatLoop: RepeatLoop) {
         output("repeat ")
+        repeatLoop.iterations?.accept(this)
+        output(" ")
         repeatLoop.body.accept(this)
+    }
+
+    override fun visit(untilLoop: UntilLoop) {
+        output("do ")
+        untilLoop.body.accept(this)
         output(" until ")
-        repeatLoop.untilCondition.accept(this)
+        untilLoop.untilCondition.accept(this)
     }
 
     override fun visit(returnStmt: Return) {
@@ -352,12 +352,8 @@ class AstToSourceCode(val output: (text: String) -> Unit, val program: Program):
     }
 
     override fun visit(assignTarget: AssignTarget) {
-        if(assignTarget.register!=null)
-            output(assignTarget.register.toString())
-        else {
-            assignTarget.memoryAddress?.accept(this)
-            assignTarget.identifier?.accept(this)
-        }
+        assignTarget.memoryAddress?.accept(this)
+        assignTarget.identifier?.accept(this)
         assignTarget.arrayindexed?.accept(this)
     }
 
@@ -398,10 +394,6 @@ class AstToSourceCode(val output: (text: String) -> Unit, val program: Program):
         outputlni("}}")
     }
 
-    override fun visit(registerExpr: RegisterExpr) {
-        output(registerExpr.register.toString())
-    }
-
     override fun visit(builtinFunctionStatementPlaceholder: BuiltinFunctionStatementPlaceholder) {
         output(builtinFunctionStatementPlaceholder.name)
     }
@@ -436,10 +428,6 @@ class AstToSourceCode(val output: (text: String) -> Unit, val program: Program):
         outputln("")
     }
 
-    override fun visit(structLv: StructLiteralValue) {
-        outputListMembers(structLv.values.asSequence(), '{', '}')
-    }
-
     override fun visit(nopStatement: NopStatement) {
         output("; NOP @ ${nopStatement.position}  $nopStatement")
     }

compiler/src/prog8/ast/AstToplevel.kt

@@ -57,7 +57,7 @@ interface INameScope {
             when(stmt) {
                 // NOTE: if other nodes are introduced that are a scope, or contain subscopes, they must be added here!
                 is ForLoop -> if(stmt.body.name==name) return stmt.body
-                is RepeatLoop -> if(stmt.body.name==name) return stmt.body
+                is UntilLoop -> if(stmt.body.name==name) return stmt.body
                 is WhileLoop -> if(stmt.body.name==name) return stmt.body
                 is BranchStatement -> {
                     if(stmt.truepart.name==name) return stmt.truepart
@@ -155,6 +155,7 @@ interface INameScope {
     }
 
     fun containsCodeOrVars() = statements.any { it !is Directive || it.directive == "%asminclude" || it.directive == "%asm"}
+    fun containsNoVars() = statements.all { it !is VarDecl }
     fun containsNoCodeNorVars() = !containsCodeOrVars()
 
     fun remove(stmt: Statement) {
@@ -174,8 +175,8 @@ interface INameScope {
                         find(it.truepart)
                         find(it.elsepart)
                     }
+                    is UntilLoop -> find(it.body)
                     is RepeatLoop -> find(it.body)
-                    is ForeverLoop -> find(it.body)
                     is WhileLoop -> find(it.body)
                     is WhenStatement -> it.choices.forEach { choice->find(choice.statements) }
                     else -> { /* do nothing */ }
@@ -186,6 +187,14 @@ interface INameScope {
         find(this)
         return result
     }
+
+    fun nextSibling(stmt: Statement): Statement? {
+        val nextIdx = statements.indexOfFirst { it===stmt } + 1
+        return if(nextIdx < statements.size)
+            statements[nextIdx]
+        else
+            null
+    }
 }
 
 interface IAssignable {
@@ -229,7 +238,7 @@ class Program(val name: String, val modules: MutableList<Module>): Node {
 
     override fun replaceChildNode(node: Node, replacement: Node) {
         require(node is Module && replacement is Module)
-        val idx = modules.indexOf(node)
+        val idx = modules.indexOfFirst { it===node }
         modules[idx] = replacement
         replacement.parent = this
     }
@@ -256,7 +265,7 @@ class Module(override val name: String,
     override fun definingScope(): INameScope = program.namespace
     override fun replaceChildNode(node: Node, replacement: Node) {
         require(node is Statement && replacement is Statement)
-        val idx = statements.indexOf(node)
+        val idx = statements.indexOfFirst { it===node }
         statements[idx] = replacement
         replacement.parent = this
     }
@@ -305,9 +314,9 @@ class GlobalNamespace(val modules: List<Module>): Node, INameScope {
         }
         // lookup something from the module.
         return when (val stmt = localContext.definingModule().lookup(scopedName, localContext)) {
-            is Label, is VarDecl, is Block, is Subroutine -> stmt
+            is Label, is VarDecl, is Block, is Subroutine, is StructDecl -> stmt
             null -> null
-            else -> throw SyntaxError("wrong identifier target for $scopedName: $stmt", stmt.position)
+            else -> throw SyntaxError("invalid identifier target type", stmt.position)
         }
     }
 }

compiler/src/prog8/ast/antlr/Antr2Kotlin.kt

@@ -161,14 +161,15 @@ private fun prog8Parser.StatementContext.toAst() : Statement {
     if(vardecl!=null) return vardecl
 
     assignment()?.let {
-        return Assignment(it.assign_target().toAst(), null, it.expression().toAst(), it.toPosition())
+        return Assignment(it.assign_target().toAst(), it.expression().toAst(), it.toPosition())
     }
 
     augassignment()?.let {
-        return Assignment(it.assign_target().toAst(),
-                it.operator.text,
-                it.expression().toAst(),
-                it.toPosition())
+        // replace A += X  with  A = A + X
+        val target = it.assign_target().toAst()
+        val oper = it.operator.text.substringBefore('=')
+        val expression = BinaryExpression(target.toExpression(), oper, it.expression().toAst(), it.expression().toPosition())
+        return Assignment(it.assign_target().toAst(), expression, it.toPosition())
     }
 
     postincrdecr()?.let {
@@ -205,21 +206,18 @@ private fun prog8Parser.StatementContext.toAst() : Statement {
     val forloop = forloop()?.toAst()
     if(forloop!=null) return forloop
 
-    val repeatloop = repeatloop()?.toAst()
-    if(repeatloop!=null) return repeatloop
+    val untilloop = untilloop()?.toAst()
+    if(untilloop!=null) return untilloop
 
     val whileloop = whileloop()?.toAst()
     if(whileloop!=null) return whileloop
 
-    val foreverloop = foreverloop()?.toAst()
-    if(foreverloop!=null) return foreverloop
+    val repeatloop = repeatloop()?.toAst()
+    if(repeatloop!=null) return repeatloop
 
     val breakstmt = breakstmt()?.toAst()
     if(breakstmt!=null) return breakstmt
 
-    val continuestmt = continuestmt()?.toAst()
-    if(continuestmt!=null) return continuestmt
-
     val whenstmt = whenstmt()?.toAst()
     if(whenstmt!=null) return whenstmt
 
@@ -247,7 +245,7 @@ private class AsmsubDecl(val name: String,
                          val returntypes: List<DataType>,
                          val asmParameterRegisters: List<RegisterOrStatusflag>,
                          val asmReturnvaluesRegisters: List<RegisterOrStatusflag>,
-                         val asmClobbers: Set<Register>)
+                         val asmClobbers: Set<CpuRegister>)
 
 private fun prog8Parser.Asmsub_declContext.toAst(): AsmsubDecl {
     val name = identifier().text
@@ -274,24 +272,43 @@ private class AsmSubroutineReturn(val type: DataType,
                                   val stack: Boolean,
                                   val position: Position)
 
-private fun prog8Parser.ClobberContext.toAst(): Set<Register>
-        = this.register().asSequence().map { it.toAst() }.toSet()
-
 private fun prog8Parser.Asmsub_returnsContext.toAst(): List<AsmSubroutineReturn>
-        = asmsub_return().map { AsmSubroutineReturn(it.datatype().toAst(), it.registerorpair()?.toAst(), it.statusregister()?.toAst(), !it.stack?.text.isNullOrEmpty(), toPosition()) }
+        = asmsub_return().map {
+            val register = it.identifier()?.toAst()
+            var registerorpair: RegisterOrPair? = null
+            var statusregister: Statusflag? = null
+            if(register!=null) {
+                when (val name = register.nameInSource.single()) {
+                    in RegisterOrPair.names -> registerorpair = RegisterOrPair.valueOf(name)
+                    in Statusflag.names -> statusregister = Statusflag.valueOf(name)
+                    else -> throw FatalAstException("invalid register or status flag in $it")
+                }
+            }
+            AsmSubroutineReturn(
+                    it.datatype().toAst(),
+                    registerorpair,
+                    statusregister,
+                    !it.stack?.text.isNullOrEmpty(), toPosition())
+        }
 
 private fun prog8Parser.Asmsub_paramsContext.toAst(): List<AsmSubroutineParameter>
         = asmsub_param().map {
     val vardecl = it.vardecl()
     val datatype = vardecl.datatype()?.toAst() ?: DataType.STRUCT
-    AsmSubroutineParameter(vardecl.varname.text, datatype,
-            it.registerorpair()?.toAst(),
-            it.statusregister()?.toAst(),
+    val register = it.identifier()?.toAst()
+    var registerorpair: RegisterOrPair? = null
+    var statusregister: Statusflag? = null
+    if(register!=null) {
+        when (val name = register.nameInSource.single()) {
+            in RegisterOrPair.names -> registerorpair = RegisterOrPair.valueOf(name)
+            in Statusflag.names -> statusregister = Statusflag.valueOf(name)
+            else -> throw FatalAstException("invalid register or status flag '$name'")
+        }
+    }
+    AsmSubroutineParameter(vardecl.varname.text, datatype, registerorpair, statusregister,
             !it.stack?.text.isNullOrEmpty(), toPosition())
 }
 
-private fun prog8Parser.StatusregisterContext.toAst() = Statusflag.valueOf(text)
-
 private fun prog8Parser.Functioncall_stmtContext.toAst(): Statement {
     val void = this.VOID() != null
     val location = scoped_identifier().toAst()
@@ -350,23 +367,22 @@ private fun prog8Parser.Sub_paramsContext.toAst(): List<SubroutineParameter> =
         }
 
 private fun prog8Parser.Assign_targetContext.toAst() : AssignTarget {
-    val register = register()?.toAst()
     val identifier = scoped_identifier()
     return when {
-        register!=null -> AssignTarget(register, null, null, null, toPosition())
-        identifier!=null -> AssignTarget(null, identifier.toAst(), null, null, toPosition())
-        arrayindexed()!=null -> AssignTarget(null, null, arrayindexed().toAst(), null, toPosition())
-        directmemory()!=null -> AssignTarget(null, null, null, DirectMemoryWrite(directmemory().expression().toAst(), toPosition()), toPosition())
-        else -> AssignTarget(null, scoped_identifier()?.toAst(), null, null, toPosition())
+        identifier!=null -> AssignTarget(identifier.toAst(), null, null, toPosition())
+        arrayindexed()!=null -> AssignTarget(null, arrayindexed().toAst(), null, toPosition())
+        directmemory()!=null -> AssignTarget(null, null, DirectMemoryWrite(directmemory().expression().toAst(), toPosition()), toPosition())
+        else -> AssignTarget(scoped_identifier()?.toAst(), null, null, toPosition())
     }
 }
 
-private fun prog8Parser.RegisterContext.toAst() = Register.valueOf(text.toUpperCase())
+private fun prog8Parser.ClobberContext.toAst() : Set<CpuRegister> {
+    val names = this.identifier().map { it.toAst().nameInSource.single() }
+    return names.map { CpuRegister.valueOf(it) }.toSet()
+}
 
 private fun prog8Parser.DatatypeContext.toAst() = DataType.valueOf(text.toUpperCase())
 
-private fun prog8Parser.RegisterorpairContext.toAst() = RegisterOrPair.valueOf(text.toUpperCase())
-
 private fun prog8Parser.ArrayindexContext.toAst() : ArrayIndex =
         ArrayIndex(expression().toAst(), toPosition())
 
@@ -469,18 +485,11 @@ private fun prog8Parser.ExpressionContext.toAst() : Expression {
                     // the ConstantFold takes care of that and converts the type if needed.
                     ArrayLiteralValue(InferredTypes.InferredType.unknown(), array, position = litval.toPosition())
                 }
-                litval.structliteral()!=null -> {
-                    val values = litval.structliteral().expression().map { it.toAst() }
-                    StructLiteralValue(values, litval.toPosition())
-                }
                 else -> throw FatalAstException("invalid parsed literal")
             }
         }
     }
 
-    if(register()!=null)
-        return RegisterExpr(register().toAst(), register().toPosition())
-
     if(scoped_identifier()!=null)
         return scoped_identifier().toAst()
 
@@ -572,19 +581,16 @@ private fun prog8Parser.Branch_stmtContext.toAst(): BranchStatement {
 private fun prog8Parser.BranchconditionContext.toAst() = BranchCondition.valueOf(text.substringAfter('_').toUpperCase())
 
 private fun prog8Parser.ForloopContext.toAst(): ForLoop {
-    val loopregister = register()?.toAst()
-    val loopvar = identifier()?.toAst()
+    val loopvar = identifier().toAst()
     val iterable = expression()!!.toAst()
     val scope =
             if(statement()!=null)
                 AnonymousScope(mutableListOf(statement().toAst()), statement().toPosition())
             else
                 AnonymousScope(statement_block().toAst(), statement_block().toPosition())
-    return ForLoop(loopregister, loopvar, iterable, scope, toPosition())
+    return ForLoop(loopvar, iterable, scope, toPosition())
 }
 
-private fun prog8Parser.ContinuestmtContext.toAst() = Continue(toPosition())
-
 private fun prog8Parser.BreakstmtContext.toAst() = Break(toPosition())
 
 private fun prog8Parser.WhileloopContext.toAst(): WhileLoop {
@@ -595,19 +601,20 @@ private fun prog8Parser.WhileloopContext.toAst(): WhileLoop {
     return WhileLoop(condition, scope, toPosition())
 }
 
-private fun prog8Parser.ForeverloopContext.toAst(): ForeverLoop {
+private fun prog8Parser.RepeatloopContext.toAst(): RepeatLoop {
+    val iterations = expression()?.toAst()
     val statements = statement_block()?.toAst() ?: mutableListOf(statement().toAst())
     val scope = AnonymousScope(statements, statement_block()?.toPosition()
             ?: statement().toPosition())
-    return ForeverLoop(scope, toPosition())
+    return RepeatLoop(iterations, scope, toPosition())
 }
 
-private fun prog8Parser.RepeatloopContext.toAst(): RepeatLoop {
+private fun prog8Parser.UntilloopContext.toAst(): UntilLoop {
     val untilCondition = expression().toAst()
     val statements = statement_block()?.toAst() ?: mutableListOf(statement().toAst())
     val scope = AnonymousScope(statements, statement_block()?.toPosition()
             ?: statement().toPosition())
-    return RepeatLoop(scope, untilCondition, toPosition())
+    return UntilLoop(scope, untilCondition, toPosition())
 }
 
 private fun prog8Parser.WhenstmtContext.toAst(): WhenStatement {

compiler/src/prog8/ast/base/Base.kt

@@ -58,13 +58,13 @@ enum class DataType {
             in ByteDatatypes -> 1
             in WordDatatypes -> 2
             FLOAT -> CompilationTarget.machine.FLOAT_MEM_SIZE
-            in PassByReferenceDatatypes -> 2
+            in PassByReferenceDatatypes -> CompilationTarget.machine.POINTER_MEM_SIZE
             else -> -9999999
         }
     }
 }
 
-enum class Register {
+enum class CpuRegister {
     A,
     X,
     Y
@@ -76,14 +76,23 @@ enum class RegisterOrPair {
     Y,
     AX,
     AY,
-    XY
+    XY;
+
+    companion object {
+        val names by lazy { values().map { it.toString()} }
+    }
+
 }       // only used in parameter and return value specs in asm subroutines
 
 enum class Statusflag {
     Pc,
     Pz,
     Pv,
-    Pn
+    Pn;
+
+    companion object {
+        val names by lazy { values().map { it.toString()} }
+    }
 }
 
 enum class BranchCondition {

compiler/src/prog8/ast/base/Extensions.kt

@@ -5,8 +5,6 @@ import prog8.ast.Program
 import prog8.ast.processing.*
 import prog8.compiler.CompilationOptions
 import prog8.compiler.BeforeAsmGenerationAstChanger
-import prog8.optimizer.AssignmentTransformer
-import prog8.optimizer.FlattenAnonymousScopesAndNopRemover
 
 
 internal fun Program.checkValid(compilerOptions: CompilationOptions, errors: ErrorReporter) {
@@ -32,15 +30,9 @@ internal fun Program.addTypecasts(errors: ErrorReporter) {
     caster.applyModifications()
 }
 
-internal fun Program.transformAssignments(errors: ErrorReporter) {
-    val transform = AssignmentTransformer(this, errors)
-    transform.visit(this)
-    while(transform.optimizationsDone>0 && errors.isEmpty()) {
-        transform.applyModifications()
-        transform.optimizationsDone = 0
-        transform.visit(this)
-    }
-    transform.applyModifications()
+internal fun Program.verifyFunctionArgTypes() {
+    val fixer = VerifyFunctionArgTypes(this)
+    fixer.visit(this)
 }
 
 internal fun Module.checkImportedValid() {
@@ -71,7 +63,8 @@ internal fun Program.checkIdentifiers(errors: ErrorReporter) {
     }
 }
 
-internal fun Program.removeNopsFlattenAnonScopes() {
-    val flattener = FlattenAnonymousScopesAndNopRemover()
-    flattener.visit(this)
+internal fun Program.variousCleanups() {
+    val process = VariousCleanups()
+    process.visit(this)
+    process.applyModifications()
 }

compiler/src/prog8/ast/expressions/AstExpressions.kt

@@ -22,28 +22,45 @@ sealed class Expression: Node {
     abstract fun constValue(program: Program): NumericLiteralValue?
     abstract fun accept(visitor: IAstVisitor)
     abstract fun accept(visitor: AstWalker, parent: Node)
-    abstract fun referencesIdentifiers(vararg name: String): Boolean     // todo: remove this and add identifier usage tracking into CallGraph instead
+    abstract fun referencesIdentifiers(vararg name: String): Boolean
     abstract fun inferType(program: Program): InferredTypes.InferredType
 
+    infix fun isSameAs(assigntarget: AssignTarget) = assigntarget.isSameAs(this)
+
     infix fun isSameAs(other: Expression): Boolean {
         if(this===other)
             return true
-        when(this) {
-            is RegisterExpr ->
-                return (other is RegisterExpr && other.register==register)
+        return when(this) {
             is IdentifierReference ->
-                return (other is IdentifierReference && other.nameInSource==nameInSource)
+                (other is IdentifierReference && other.nameInSource==nameInSource)
             is PrefixExpression ->
-                return (other is PrefixExpression && other.operator==operator && other.expression isSameAs expression)
+                (other is PrefixExpression && other.operator==operator && other.expression isSameAs expression)
             is BinaryExpression ->
-                return (other is BinaryExpression && other.operator==operator
+                (other is BinaryExpression && other.operator==operator
                         && other.left isSameAs left
                         && other.right isSameAs right)
             is ArrayIndexedExpression -> {
-                return (other is ArrayIndexedExpression && other.identifier.nameInSource == identifier.nameInSource
+                (other is ArrayIndexedExpression && other.identifier.nameInSource == identifier.nameInSource
                         && other.arrayspec.index isSameAs arrayspec.index)
             }
-            else -> return other==this
+            is DirectMemoryRead -> {
+                (other is DirectMemoryRead && other.addressExpression isSameAs addressExpression)
+            }
+            is TypecastExpression -> {
+                (other is TypecastExpression && other.implicit==implicit && other.type==type && other.expression isSameAs expression)
+            }
+            is AddressOf -> {
+                (other is AddressOf && other.identifier.nameInSource == identifier.nameInSource)
+            }
+            is RangeExpr -> {
+                (other is RangeExpr && other.from==from && other.to==to && other.step==step)
+            }
+            is FunctionCall -> {
+                (other is FunctionCall && other.target.nameInSource == target.nameInSource
+                        && other.args.size == args.size
+                        && other.args.zip(args).all { it.first isSameAs it.second } )
+            }
+            else -> other==this
         }
     }
 }
@@ -277,7 +294,7 @@ class TypecastExpression(var expression: Expression, var type: DataType, val imp
     override fun inferType(program: Program): InferredTypes.InferredType = InferredTypes.knownFor(type)
     override fun constValue(program: Program): NumericLiteralValue? {
         val cv = expression.constValue(program) ?: return null
-        return cv.cast(type)
+        return cv.castNoCheck(type)
         // val value = RuntimeValue(cv.type, cv.asNumericValue!!).cast(type)
         // return LiteralValue.fromNumber(value.numericValue(), value.type, position).cast(type)
     }
@@ -398,7 +415,7 @@ class NumericLiteralValue(val type: DataType,    // only numerical types allowed
 
     operator fun compareTo(other: NumericLiteralValue): Int = number.toDouble().compareTo(other.number.toDouble())
 
-    fun cast(targettype: DataType): NumericLiteralValue {
+    fun castNoCheck(targettype: DataType): NumericLiteralValue {
         if(type==targettype)
             return this
         val numval = number.toDouble()
@@ -457,31 +474,6 @@ class NumericLiteralValue(val type: DataType,    // only numerical types allowed
     }
 }
 
-class StructLiteralValue(var values: List<Expression>,
-                         override val position: Position): Expression() {
-    override lateinit var parent: Node
-
-    override fun linkParents(parent: Node) {
-        this.parent=parent
-        values.forEach { it.linkParents(this) }
-    }
-
-    override fun replaceChildNode(node: Node, replacement: Node) {
-        throw FatalAstException("can't replace here")
-    }
-
-    override fun constValue(program: Program): NumericLiteralValue?  = null
-    override fun accept(visitor: IAstVisitor) = visitor.visit(this)
-    override fun accept(visitor: AstWalker, parent: Node)= visitor.visit(this, parent)
-
-    override fun referencesIdentifiers(vararg name: String) = values.any { it.referencesIdentifiers(*name) }
-    override fun inferType(program: Program): InferredTypes.InferredType = InferredTypes.knownFor(DataType.STRUCT)
-
-    override fun toString(): String {
-        return "struct{ ${values.joinToString(", ")} }"
-    }
-}
-
 private var heapIdSequence = 0   // unique ids for strings and arrays "on the heap"
 
 class StringLiteralValue(val value: String,
@@ -529,7 +521,7 @@ class ArrayLiteralValue(val type: InferredTypes.InferredType,     // inferred be
 
     override fun replaceChildNode(node: Node, replacement: Node) {
         require(replacement is Expression)
-        val idx = value.indexOf(node)
+        val idx = value.indexOfFirst { it===node }
         value[idx] = replacement
         replacement.parent = this
     }
@@ -592,7 +584,7 @@ class ArrayLiteralValue(val type: InferredTypes.InferredType,     // inferred be
                     it
                 } else {
                     try {
-                        num.cast(elementType)
+                        num.castNoCheck(elementType)
                     } catch(x: ExpressionError) {
                         return null
                     }
@@ -696,29 +688,6 @@ internal fun makeRange(fromVal: Int, toVal: Int, stepVal: Int): IntProgression {
     }
 }
 
-class RegisterExpr(val register: Register, override val position: Position) : Expression(), IAssignable {
-    override lateinit var parent: Node
-
-    override fun linkParents(parent: Node) {
-        this.parent = parent
-    }
-
-    override fun replaceChildNode(node: Node, replacement: Node) {
-        throw FatalAstException("can't replace here")
-    }
-
-    override fun constValue(program: Program): NumericLiteralValue? = null
-    override fun accept(visitor: IAstVisitor) = visitor.visit(this)
-    override fun accept(visitor: AstWalker, parent: Node)= visitor.visit(this, parent)
-
-    override fun referencesIdentifiers(vararg name: String): Boolean = register.name in name
-    override fun toString(): String {
-        return "RegisterExpr(register=$register, pos=$position)"
-    }
-
-    override fun inferType(program: Program): InferredTypes.InferredType = InferredTypes.knownFor(DataType.UBYTE)
-}
-
 data class IdentifierReference(val nameInSource: List<String>, override val position: Position) : Expression(), IAssignable {
     override lateinit var parent: Node
 
@@ -731,6 +700,9 @@ data class IdentifierReference(val nameInSource: List<String>, override val posi
     fun targetVarDecl(namespace: INameScope): VarDecl? = targetStatement(namespace) as? VarDecl
     fun targetSubroutine(namespace: INameScope): Subroutine? = targetStatement(namespace) as? Subroutine
 
+    override fun equals(other: Any?) = other is IdentifierReference && other.nameInSource==nameInSource
+    override fun hashCode() = nameInSource.hashCode()
+
     override fun linkParents(parent: Node) {
         this.parent = parent
     }
@@ -761,11 +733,10 @@ data class IdentifierReference(val nameInSource: List<String>, override val posi
     override fun referencesIdentifiers(vararg name: String): Boolean = nameInSource.last() in name
 
     override fun inferType(program: Program): InferredTypes.InferredType {
-        val targetStmt = targetStatement(program.namespace)
-        return if(targetStmt is VarDecl) {
-            InferredTypes.knownFor(targetStmt.datatype)
-        } else {
-            InferredTypes.InferredType.unknown()
+        return when (val targetStmt = targetStatement(program.namespace)) {
+            is VarDecl -> InferredTypes.knownFor(targetStmt.datatype)
+            is StructDecl -> InferredTypes.knownFor(DataType.STRUCT)
+            else -> InferredTypes.InferredType.unknown()
         }
     }
 
@@ -798,7 +769,7 @@ class FunctionCall(override var target: IdentifierReference,
         if(node===target)
             target=replacement as IdentifierReference
         else {
-            val idx = args.indexOf(node)
+            val idx = args.indexOfFirst { it===node }
             args[idx] = replacement as Expression
         }
         replacement.parent = this

compiler/src/prog8/ast/processing/AstChecker.kt

@@ -110,49 +110,37 @@ internal class AstChecker(private val program: Program,
     }
 
     override fun visit(forLoop: ForLoop) {
-        if(forLoop.body.containsNoCodeNorVars())
-            errors.warn("for loop body is empty", forLoop.position)
-
         val iterableDt = forLoop.iterable.inferType(program).typeOrElse(DataType.BYTE)
         if(iterableDt !in IterableDatatypes && forLoop.iterable !is RangeExpr) {
             errors.err("can only loop over an iterable type", forLoop.position)
         } else {
-            if (forLoop.loopRegister != null) {
-                // loop register
-                if (iterableDt != DataType.ARRAY_UB && iterableDt != DataType.ARRAY_B && iterableDt != DataType.STR)
-                    errors.err("register can only loop over bytes", forLoop.position)
-                if(forLoop.loopRegister!=Register.A)
-                    errors.err("it's only possible to use A as a loop register", forLoop.position)
+            val loopvar = forLoop.loopVar.targetVarDecl(program.namespace)
+            if(loopvar==null || loopvar.type== VarDeclType.CONST) {
+                errors.err("for loop requires a variable to loop with", forLoop.position)
             } else {
-                // loop variable
-                val loopvar = forLoop.loopVar!!.targetVarDecl(program.namespace)
-                if(loopvar==null || loopvar.type== VarDeclType.CONST) {
-                    errors.err("for loop requires a variable to loop with", forLoop.position)
-                } else {
-                    when (loopvar.datatype) {
-                        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)
-                        }
-                        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)
-                        }
-                        DataType.BYTE -> {
-                            if(iterableDt!= DataType.BYTE && iterableDt!= DataType.ARRAY_B)
-                                errors.err("byte loop variable can only loop over bytes", forLoop.position)
-                        }
-                        DataType.WORD -> {
-                            if(iterableDt!= DataType.BYTE && iterableDt!= DataType.WORD &&
-                                    iterableDt != DataType.ARRAY_B && iterableDt!= DataType.ARRAY_W)
-                                errors.err("word loop variable can only loop over bytes or words", forLoop.position)
-                        }
-                        DataType.FLOAT -> {
-                            errors.err("for loop only supports integers", forLoop.position)
-                        }
-                        else -> errors.err("loop variable must be numeric type", forLoop.position)
+                when (loopvar.datatype) {
+                    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)
                     }
+                    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)
+                    }
+                    DataType.BYTE -> {
+                        if(iterableDt!= DataType.BYTE && iterableDt!= DataType.ARRAY_B)
+                            errors.err("byte loop variable can only loop over bytes", forLoop.position)
+                    }
+                    DataType.WORD -> {
+                        if(iterableDt!= DataType.BYTE && iterableDt!= DataType.WORD &&
+                                iterableDt != DataType.ARRAY_B && iterableDt!= DataType.ARRAY_W)
+                            errors.err("word loop variable can only loop over bytes or words", forLoop.position)
+                    }
+                    DataType.FLOAT -> {
+                        errors.err("for loop only supports integers", forLoop.position)
+                    }
+                    else -> errors.err("loop variable must be numeric type", forLoop.position)
                 }
             }
         }
@@ -260,27 +248,27 @@ internal class AstChecker(private val program: Program,
                 }
             }
 
-            val regCounts = mutableMapOf<Register, Int>().withDefault { 0 }
+            val regCounts = mutableMapOf<CpuRegister, Int>().withDefault { 0 }
             val statusflagCounts = mutableMapOf<Statusflag, Int>().withDefault { 0 }
             fun countRegisters(from: Iterable<RegisterOrStatusflag>) {
                 regCounts.clear()
                 statusflagCounts.clear()
                 for(p in from) {
                     when(p.registerOrPair) {
-                        RegisterOrPair.A -> regCounts[Register.A]=regCounts.getValue(Register.A)+1
-                        RegisterOrPair.X -> regCounts[Register.X]=regCounts.getValue(Register.X)+1
-                        RegisterOrPair.Y -> regCounts[Register.Y]=regCounts.getValue(Register.Y)+1
+                        RegisterOrPair.A -> regCounts[CpuRegister.A]=regCounts.getValue(CpuRegister.A)+1
+                        RegisterOrPair.X -> regCounts[CpuRegister.X]=regCounts.getValue(CpuRegister.X)+1
+                        RegisterOrPair.Y -> regCounts[CpuRegister.Y]=regCounts.getValue(CpuRegister.Y)+1
                         RegisterOrPair.AX -> {
-                            regCounts[Register.A]=regCounts.getValue(Register.A)+1
-                            regCounts[Register.X]=regCounts.getValue(Register.X)+1
+                            regCounts[CpuRegister.A]=regCounts.getValue(CpuRegister.A)+1
+                            regCounts[CpuRegister.X]=regCounts.getValue(CpuRegister.X)+1
                         }
                         RegisterOrPair.AY -> {
-                            regCounts[Register.A]=regCounts.getValue(Register.A)+1
-                            regCounts[Register.Y]=regCounts.getValue(Register.Y)+1
+                            regCounts[CpuRegister.A]=regCounts.getValue(CpuRegister.A)+1
+                            regCounts[CpuRegister.Y]=regCounts.getValue(CpuRegister.Y)+1
                         }
                         RegisterOrPair.XY -> {
-                            regCounts[Register.X]=regCounts.getValue(Register.X)+1
-                            regCounts[Register.Y]=regCounts.getValue(Register.Y)+1
+                            regCounts[CpuRegister.X]=regCounts.getValue(CpuRegister.X)+1
+                            regCounts[CpuRegister.Y]=regCounts.getValue(CpuRegister.Y)+1
                         }
                         null ->
                             if(p.statusflag!=null)
@@ -316,26 +304,20 @@ internal class AstChecker(private val program: Program,
         } else {
             // Pass-by-reference datatypes can not occur as parameters to a subroutine directly
             // Instead, their reference (address) should be passed (as an UWORD).
-            // The language has no typed pointers at this time.
+            // TODO The language has no (typed) pointers at this time.  Should this be handled better?
             if(subroutine.parameters.any{it.type in PassByReferenceDatatypes }) {
-                err("Pass-by-reference types (str, array) cannot occur as a parameter type directly. Instead, use an uword for their address, or access the variable from the outer scope directly.")
+                err("Pass-by-reference types (str, array) cannot occur as a parameter type directly. Instead, use an uword to receive their address, or access the variable from the outer scope directly.")
             }
         }
-
-        visitStatements(subroutine.statements)
     }
 
-    override fun visit(repeatLoop: RepeatLoop) {
-        if(repeatLoop.untilCondition.referencesIdentifiers("A", "X", "Y"))   // TODO use callgraph?
-            errors.warn("using a register in the loop condition is risky (it could get clobbered)", repeatLoop.untilCondition.position)
-        if(repeatLoop.untilCondition.inferType(program).typeOrElse(DataType.STRUCT) !in IntegerDatatypes)
-            errors.err("condition value should be an integer type", repeatLoop.untilCondition.position)
-        super.visit(repeatLoop)
+    override fun visit(untilLoop: UntilLoop) {
+        if(untilLoop.untilCondition.inferType(program).typeOrElse(DataType.STRUCT) !in IntegerDatatypes)
+            errors.err("condition value should be an integer type", untilLoop.untilCondition.position)
+        super.visit(untilLoop)
     }
 
     override fun visit(whileLoop: WhileLoop) {
-        if(whileLoop.condition.referencesIdentifiers("A", "X", "Y"))        // TODO use callgraph?
-            errors.warn("using a register in the loop condition is risky (it could get clobbered)", whileLoop.condition.position)
         if(whileLoop.condition.inferType(program).typeOrElse(DataType.STRUCT) !in IntegerDatatypes)
             errors.err("condition value should be an integer type", whileLoop.condition.position)
         super.visit(whileLoop)
@@ -361,9 +343,9 @@ internal class AstChecker(private val program: Program,
         if(targetIdent!=null) {
             val targetVar = targetIdent.targetVarDecl(program.namespace)
             if(targetVar?.struct != null) {
-                val sourceStructLv = assignment.value as? StructLiteralValue
+                val sourceStructLv = assignment.value as? ArrayLiteralValue
                 if (sourceStructLv != null) {
-                    if (sourceStructLv.values.size != targetVar.struct?.numberOfElements)
+                    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
@@ -378,9 +360,15 @@ internal class AstChecker(private val program: Program,
             }
         }
 
-        if(assignment.value.inferType(program) != assignment.target.inferType(program, assignment))
+        val targetDt = assignment.target.inferType(program, assignment)
+        if(assignment.value.inferType(program) != targetDt)
             errors.err("assignment value is of different type as the target", assignment.value.position)
 
+        if(assignment.value is TypecastExpression) {
+            if(assignment.isAugmentable && targetDt.istype(DataType.FLOAT))
+                errors.err("typecasting a float value in-place makes no sense", assignment.value.position)
+        }
+
         super.visit(assignment)
     }
 
@@ -397,8 +385,7 @@ internal class AstChecker(private val program: Program,
         val targetIdentifier = assignTarget.identifier
         if (targetIdentifier != null) {
             val targetName = targetIdentifier.nameInSource
-            val targetSymbol = program.namespace.lookup(targetName, assignment)
-            when (targetSymbol) {
+            when (val targetSymbol = program.namespace.lookup(targetName, assignment)) {
                 null -> {
                     errors.err("undefined symbol: ${targetIdentifier.nameInSource.joinToString(".")}", targetIdentifier.position)
                     return
@@ -451,7 +438,9 @@ internal class AstChecker(private val program: Program,
         if(variable==null)
             errors.err("pointer-of operand must be the name of a heap variable", addressOf.position)
         else {
-            if(variable.datatype !in ArrayDatatypes && variable.datatype != DataType.STR && variable.datatype!=DataType.STRUCT)
+            if(variable.datatype !in ArrayDatatypes
+                    && variable.type!=VarDeclType.MEMORY
+                    && variable.datatype != DataType.STR && variable.datatype!=DataType.STRUCT)
                 errors.err("invalid pointer-of operand type", addressOf.position)
         }
         super.visit(addressOf)
@@ -463,7 +452,6 @@ internal class AstChecker(private val program: Program,
         }
 
         // the initializer value can't refer to the variable itself (recursive definition)
-        // TODO use callgraph for check?
         if(decl.value?.referencesIdentifiers(decl.name) == true || decl.arraysize?.index?.referencesIdentifiers(decl.name) == true) {
             err("recursive var declaration")
         }
@@ -510,29 +498,21 @@ internal class AstChecker(private val program: Program,
 
                 when(decl.value) {
                     null -> {
-                        // a vardecl without an initial value, don't bother with the rest
-                        return super.visit(decl)
+                        // a vardecl without an initial value, don't bother with it
                     }
                     is RangeExpr -> throw FatalAstException("range expression should have been converted to a true array value")
                     is StringLiteralValue -> {
                         checkValueTypeAndRangeString(decl.datatype, decl.value as StringLiteralValue)
                     }
                     is ArrayLiteralValue -> {
-                        val arraySpec = decl.arraysize ?: ArrayIndex.forArray(decl.value as ArrayLiteralValue)
-                        checkValueTypeAndRangeArray(decl.datatype, decl.struct, arraySpec, decl.value as ArrayLiteralValue)
-                    }
-                    is NumericLiteralValue -> {
-                        checkValueTypeAndRange(decl.datatype, decl.value as NumericLiteralValue)
-                    }
-                    is StructLiteralValue -> {
                         if(decl.datatype==DataType.STRUCT) {
                             val struct = decl.struct!!
-                            val structLv = decl.value as StructLiteralValue
-                            if(struct.numberOfElements != structLv.values.size) {
+                            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.values.zip(struct.statements)) {
+                            for(value in structLv.value.zip(struct.statements)) {
                                 val memberdecl = value.second as VarDecl
                                 val constValue = value.first.constValue(program)
                                 if(constValue==null) {
@@ -546,9 +526,13 @@ internal class AstChecker(private val program: Program,
                                 }
                             }
                         } else {
-                            errors.err("struct literal is wrong type to initialize this variable", decl.value!!.position)
+                            val arraySpec = decl.arraysize ?: ArrayIndex.forArray(decl.value as ArrayLiteralValue)
+                            checkValueTypeAndRangeArray(decl.datatype, decl.struct, arraySpec, decl.value as ArrayLiteralValue)
                         }
                     }
+                    is NumericLiteralValue -> {
+                        checkValueTypeAndRange(decl.datatype, decl.value as NumericLiteralValue)
+                    }
                     else -> {
                         err("var/const declaration needs a compile-time constant initializer value, or range, instead found: ${decl.value!!.javaClass.simpleName}")
                         super.visit(decl)
@@ -585,8 +569,38 @@ internal class AstChecker(private val program: Program,
         }
 
         val declValue = decl.value
-        if(declValue!=null && decl.type==VarDeclType.VAR && !declValue.inferType(program).istype(decl.datatype))
-            err("initialisation value has incompatible type (${declValue.inferType(program)}) for the variable (${decl.datatype})", declValue.position)
+        if(declValue!=null && decl.type==VarDeclType.VAR) {
+            if(decl.datatype==DataType.STRUCT) {
+                val valueIdt = declValue.inferType(program)
+                if(valueIdt.isUnknown)
+                    throw AstException("invalid value type")
+                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)) {
+                err("initialisation value has incompatible type (${declValue.inferType(program)}) for the variable (${decl.datatype})", declValue.position)
+            }
+        }
+
+        // array length limits
+        if(decl.isArray) {
+            val length = decl.arraysize!!.size() ?: 1
+            when (decl.datatype) {
+                DataType.STR, DataType.ARRAY_UB, DataType.ARRAY_B -> {
+                    if(length==0 || length>256)
+                        err("string and byte array length must be 1-256")
+                }
+                DataType.ARRAY_UW, DataType.ARRAY_W -> {
+                    if(length==0 || length>128)
+                        err("word array length must be 1-128")
+                }
+                DataType.ARRAY_F -> {
+                    if(length==0 || length>51)
+                        err("float array length must be 1-51")
+                }
+                else -> {}
+            }
+        }
 
         super.visit(decl)
     }
@@ -702,12 +716,20 @@ internal class AstChecker(private val program: Program,
     }
 
     override fun visit(expr: PrefixExpression) {
+        val dt = expr.inferType(program).typeOrElse(DataType.STRUCT)
         if(expr.operator=="-") {
-            val dt = expr.inferType(program).typeOrElse(DataType.STRUCT)
             if (dt != DataType.BYTE && dt != DataType.WORD && dt != DataType.FLOAT) {
                 errors.err("can only take negative of a signed number type", expr.position)
             }
         }
+        else if(expr.operator == "not") {
+            if(dt !in IntegerDatatypes)
+                errors.err("can only use boolean not on integer types", expr.position)
+        }
+        else if(expr.operator == "~") {
+            if(dt !in IntegerDatatypes)
+                errors.err("can only use bitwise invert on integer types", expr.position)
+        }
         super.visit(expr)
     }
 
@@ -733,7 +755,7 @@ internal class AstChecker(private val program: Program,
             }
             "**" -> {
                 if(leftDt in IntegerDatatypes)
-                    errors.err("power operator requires floating point", expr.position)
+                    errors.err("power operator requires floating point operands", expr.position)
             }
             "and", "or", "xor" -> {
                 // only integer numeric operands accepted, and if literal constants, only boolean values accepted (0 or 1)
@@ -750,7 +772,7 @@ internal class AstChecker(private val program: Program,
                     errors.err("bitwise operator can only be used on integer operands", expr.right.position)
             }
             "<<", ">>" -> {
-                // for now, bit-shifts can only shift by a constant number
+                // for now, bit-shifts can only shift by a constant number  TODO remove this restriction
                 val constRight = expr.right.constValue(program)
                 if(constRight==null)
                     errors.err("bit-shift can only be done by a constant number (for now)", expr.right.position)
@@ -821,6 +843,10 @@ internal class AstChecker(private val program: Program,
                 errors.warn("sgn() of unsigned type is always 0 or 1, this is perhaps not what was intended", functionCall.args.first().position)
         }
 
+        val error = VerifyFunctionArgTypes.checkTypes(functionCall, functionCall.definingScope(), program)
+        if(error!=null)
+            errors.err(error, functionCall.args.first().position)
+
         super.visit(functionCall)
     }
 
@@ -845,10 +871,16 @@ internal class AstChecker(private val program: Program,
 
         if(functionCallStatement.target.nameInSource.last() in setOf("lsl", "lsr", "rol", "ror", "rol2", "ror2", "swap", "sort", "reverse")) {
             // in-place modification, can't be done on literals
-            if(functionCallStatement.args.any { it !is IdentifierReference && it !is RegisterExpr && it !is ArrayIndexedExpression && it !is DirectMemoryRead }) {
+            if(functionCallStatement.args.any { it !is IdentifierReference && it !is ArrayIndexedExpression && it !is DirectMemoryRead }) {
                 errors.err("invalid argument to a in-place modifying function", functionCallStatement.args.first().position)
             }
         }
+
+        val error = VerifyFunctionArgTypes.checkTypes(functionCallStatement, functionCallStatement.definingScope(), program)
+        if(error!=null) {
+            errors.err(error, functionCallStatement.args.firstOrNull()?.position ?: functionCallStatement.position)
+        }
+
         super.visit(functionCallStatement)
     }
 
@@ -857,79 +889,38 @@ internal class AstChecker(private val program: Program,
             errors.err("cannot use arguments when calling a label", position)
 
         if(target is BuiltinFunctionStatementPlaceholder) {
-            // it's a call to a builtin function.
-            val func = BuiltinFunctions.getValue(target.name)
-            if(args.size!=func.parameters.size)
-                errors.err("invalid number of arguments", position)
-            else {
-                val paramTypesForAddressOf = PassByReferenceDatatypes + DataType.UWORD
-                for (arg in args.withIndex().zip(func.parameters)) {
-                    val argDt=arg.first.value.inferType(program)
-                    if (argDt.isKnown
-                            && !(argDt.typeOrElse(DataType.STRUCT) isAssignableTo arg.second.possibleDatatypes)
-                            && (argDt.typeOrElse(DataType.STRUCT) != DataType.UWORD || arg.second.possibleDatatypes.intersect(paramTypesForAddressOf).isEmpty())) {
-                        errors.err("builtin function '${target.name}' argument ${arg.first.index + 1} has invalid type $argDt, expected ${arg.second.possibleDatatypes}", position)
-                    }
+            if(target.name=="swap") {
+                // swap() is a bit weird because this one is translated into a operations directly, instead of being a function call
+                val dt1 = args[0].inferType(program)
+                val dt2 = args[1].inferType(program)
+                if (dt1 != dt2)
+                    errors.err("swap requires 2 args of identical type", position)
+                else if (args[0].constValue(program) != null || args[1].constValue(program) != null)
+                    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)
+                    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.namespace)?.datatype == DataType.STR) {
+                    errors.err("any/all on a string is useless (is always true unless the string is empty)", position)
                 }
-                if(target.name=="swap") {
-                    // swap() is a bit weird because this one is translated into a operations directly, instead of being a function call
-                    val dt1 = args[0].inferType(program)
-                    val dt2 = args[1].inferType(program)
-                    if (dt1 != dt2)
-                        errors.err("swap requires 2 args of identical type", position)
-                    else if (args[0].constValue(program) != null || args[1].constValue(program) != null)
-                        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)
-                        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.namespace)?.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) {
-                        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) {
+                    errors.err("any/all on a string is useless (is always true unless the string is empty)", position)
                 }
             }
         } else if(target is Subroutine) {
             if(target.regXasResult())
                 errors.warn("subroutine call return value in X register is discarded and replaced by 0", position)
-            if(args.size!=target.parameters.size)
-                errors.err("invalid number of arguments", position)
-            else {
+            if(target.isAsmSubroutine) {
                 for (arg in args.withIndex().zip(target.parameters)) {
                     val argIDt = arg.first.value.inferType(program)
-                    if(!argIDt.isKnown) {
+                    if (!argIDt.isKnown)
                         return
-                    }
-                    val argDt=argIDt.typeOrElse(DataType.STRUCT)
-                    if(!(argDt isAssignableTo arg.second.type)) {
-                        // for asm subroutines having STR param it's okay to provide a UWORD (address value)
-                        if(!(target.isAsmSubroutine && arg.second.type == DataType.STR && argDt == DataType.UWORD))
-                            errors.err("subroutine '${target.name}' argument ${arg.first.index + 1} has invalid type $argDt, expected ${arg.second.type}", position)
-                    }
-
-                    if(target.isAsmSubroutine) {
-                        if (target.asmParameterRegisters[arg.first.index].registerOrPair in setOf(RegisterOrPair.AX, RegisterOrPair.XY, RegisterOrPair.X)) {
-                            if (arg.first.value !is NumericLiteralValue && arg.first.value !is IdentifierReference)
-                                errors.warn("calling a subroutine that expects X as a parameter is problematic. If you see a compiler error/crash about this later, try to change this call", position)
-                        }
-
-                        // check if the argument types match the register(pairs)
-                        val asmParamReg = target.asmParameterRegisters[arg.first.index]
-                        if(asmParamReg.statusflag!=null) {
-                            if(argDt !in ByteDatatypes)
-                                errors.err("subroutine '${target.name}' argument ${arg.first.index + 1} must be byte type for statusflag", position)
-                        } else if(asmParamReg.registerOrPair in setOf(RegisterOrPair.A, RegisterOrPair.X, RegisterOrPair.Y)) {
-                            if(argDt !in ByteDatatypes)
-                                errors.err("subroutine '${target.name}' argument ${arg.first.index + 1} must be byte type for single register", position)
-                        } else if(asmParamReg.registerOrPair in setOf(RegisterOrPair.AX, RegisterOrPair.AY, RegisterOrPair.XY)) {
-                            if(argDt !in WordDatatypes + IterableDatatypes)
-                                errors.err("subroutine '${target.name}' argument ${arg.first.index + 1} must be word type for register pair", position)
-                        }
-                    }
+                    if (target.asmParameterRegisters[arg.first.index].registerOrPair in setOf(RegisterOrPair.AX, RegisterOrPair.XY, RegisterOrPair.X)
+                            && arg.first.value !is NumericLiteralValue && arg.first.value !is IdentifierReference)
+                        errors.warn("calling a subroutine that expects X as a parameter is problematic. If you see a compiler error/crash about this later, try to change this call", position)
                 }
             }
         }
@@ -1050,30 +1041,6 @@ internal class AstChecker(private val program: Program,
         }
     }
 
-    override fun visit(scope: AnonymousScope) {
-        visitStatements(scope.statements)
-    }
-
-    private fun visitStatements(statements: List<Statement>) {
-        for((index, stmt) in statements.withIndex()) {
-            if(index < statements.lastIndex && statements[index+1] !is Subroutine) {
-                when {
-                    stmt is FunctionCallStatement && stmt.target.nameInSource.last() == "exit" -> {
-                        errors.warn("unreachable code, preceding exit call will never return", statements[index + 1].position)
-                    }
-                    stmt is Return && statements[index + 1] !is Subroutine -> {
-                        errors.warn("unreachable code, preceding return statement", statements[index + 1].position)
-                    }
-                    stmt is Jump && statements[index + 1] !is Subroutine -> {
-                        errors.warn("unreachable code, preceding jump statement", statements[index + 1].position)
-                    }
-                }
-            }
-
-            stmt.accept(this)
-        }
-    }
-
     private fun checkFunctionOrLabelExists(target: IdentifierReference, statement: Statement): Statement? {
         val targetStatement = target.targetStatement(program.namespace)
         if(targetStatement is Label || targetStatement is Subroutine || targetStatement is BuiltinFunctionStatementPlaceholder)
@@ -1248,7 +1215,7 @@ internal class AstChecker(private val program: Program,
                 is AddressOf -> it.identifier.heapId(program.namespace)
                 is TypecastExpression -> {
                     val constVal = it.expression.constValue(program)
-                    constVal?.cast(it.type)?.number?.toInt() ?: -9999999
+                    constVal?.castNoCheck(it.type)?.number?.toInt() ?: -9999999
                 }
                 else -> -9999999
             }
@@ -1293,8 +1260,8 @@ internal class AstChecker(private val program: Program,
             DataType.STR -> sourceDatatype== DataType.STR
             DataType.STRUCT -> {
                 if(sourceDatatype==DataType.STRUCT) {
-                    val structLv = sourceValue as StructLiteralValue
-                    val numValues = structLv.values.size
+                    val structLv = sourceValue as ArrayLiteralValue
+                    val numValues = structLv.value.size
                     val targetstruct = target.identifier!!.targetVarDecl(program.namespace)!!.struct!!
                     return targetstruct.numberOfElements == numValues
                 }

compiler/src/prog8/ast/processing/AstIdentifiersChecker.kt

@@ -57,8 +57,8 @@ internal class AstIdentifiersChecker(private val program: Program, private val e
                 return super.visit(decl)
             }
 
-            if (decl.value != null && decl.value !is StructLiteralValue) {
-                errors.err("initializing requires struct literal value", decl.value?.position ?: decl.position)
+            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)
             }
         }
@@ -137,21 +137,6 @@ internal class AstIdentifiersChecker(private val program: Program, private val e
         super.visit(label)
     }
 
-    override fun visit(forLoop: ForLoop) {
-        if (forLoop.loopRegister != null) {
-            if (forLoop.loopRegister == Register.X)
-                errors.warn("writing to the X register is dangerous, because it's used as an internal pointer", forLoop.position)
-        }
-
-        super.visit(forLoop)
-    }
-
-    override fun visit(assignTarget: AssignTarget) {
-        if(assignTarget.register== Register.X)
-            errors.warn("writing to the X register is dangerous, because it's used as an internal pointer", assignTarget.position)
-        super.visit(assignTarget)
-    }
-
     override fun visit(string: StringLiteralValue) {
         if (string.value.length !in 1..255)
             errors.err("string literal length must be between 1 and 255", string.position)

compiler/src/prog8/ast/processing/AstVariousTransforms.kt

@@ -10,13 +10,38 @@ import prog8.ast.statements.*
 internal class AstVariousTransforms(private val program: Program) : AstWalker() {
     private val noModifications = emptyList<IAstModification>()
 
-    override fun before(functionCall: FunctionCall, parent: Node): Iterable<IAstModification> {
-        if(functionCall.target.nameInSource.size==1 && functionCall.target.nameInSource[0]=="lsb") {
-            // lsb(...) is just an alias for type cast to ubyte, so replace with "... as ubyte"
-            val typecast = TypecastExpression(functionCall.args.single(), DataType.UBYTE, false, functionCall.position)
-            return listOf(IAstModification.ReplaceNode(
-                    functionCall, typecast, parent
-            ))
+    override fun after(functionCallStatement: FunctionCallStatement, parent: Node): Iterable<IAstModification> {
+        if(functionCallStatement.target.nameInSource == listOf("swap")) {
+            // if x and y are both just identifiers, do not rewrite (there should be asm generation for that)
+            // otherwise:
+            // rewrite swap(x,y) as follows:
+            // - declare a temp variable of the same datatype
+            // - temp = x, x = y, y= temp
+            val first = functionCallStatement.args[0]
+            val second = functionCallStatement.args[1]
+            if(first !is IdentifierReference && second !is IdentifierReference) {
+                val dt = first.inferType(program).typeOrElse(DataType.STRUCT)
+                val tempname = "prog8_swaptmp_${functionCallStatement.hashCode()}"
+                val tempvardecl = VarDecl(VarDeclType.VAR, dt, ZeropageWish.DONTCARE, null, tempname, null, null, isArray = false, autogeneratedDontRemove = true, position = first.position)
+                val tempvar = IdentifierReference(listOf(tempname), first.position)
+                val assignTemp = Assignment(
+                        AssignTarget(tempvar, null, null, first.position),
+                        first,
+                        first.position
+                )
+                val assignFirst = Assignment(
+                        AssignTarget.fromExpr(first),
+                        second,
+                        first.position
+                )
+                val assignSecond = Assignment(
+                        AssignTarget.fromExpr(second),
+                        tempvar,
+                        first.position
+                )
+                val scope = AnonymousScope(mutableListOf(tempvardecl, assignTemp, assignFirst, assignSecond), first.position)
+                return listOf(IAstModification.ReplaceNode(functionCallStatement, scope, parent))
+            }
         }
 
         return noModifications
@@ -43,13 +68,16 @@ internal class AstVariousTransforms(private val program: Program) : AstWalker()
         val symbolsInSub = subroutine.allDefinedSymbols()
         val namesInSub = symbolsInSub.map{ it.first }.toSet()
         if(subroutine.asmAddress==null) {
-            if(subroutine.asmParameterRegisters.isEmpty()) {
-                return subroutine.parameters
-                        .filter { it.name !in namesInSub }
-                        .map {
-                            val vardecl = ParameterVarDecl(it.name, it.type, subroutine.position)
-                            IAstModification.InsertFirst(vardecl, subroutine)
-                        }
+            if(subroutine.asmParameterRegisters.isEmpty() && subroutine.parameters.isNotEmpty()) {
+                val vars = subroutine.statements.filterIsInstance<VarDecl>().map { it.name }.toSet()
+                if(!vars.containsAll(subroutine.parameters.map{it.name})) {
+                    return subroutine.parameters
+                            .filter { it.name !in namesInSub }
+                            .map {
+                                val vardecl = ParameterVarDecl(it.name, it.type, subroutine.position)
+                                IAstModification.InsertFirst(vardecl, subroutine)
+                            }
+                }
             }
         }
 
@@ -104,11 +132,11 @@ internal class AstVariousTransforms(private val program: Program) : AstWalker()
                 // this array literal is part of an expression, turn it into an identifier reference
                 val litval2 = array.cast(arrayDt.typeOrElse(DataType.STRUCT))
                 if(litval2!=null && litval2!=array) {
-                    val vardecl = VarDecl.createAuto(litval2)
-                    val identifier = IdentifierReference(listOf(vardecl.name), vardecl.position)
+                    val vardecl2 = VarDecl.createAuto(litval2)
+                    val identifier = IdentifierReference(listOf(vardecl2.name), vardecl2.position)
                     return listOf(
                             IAstModification.ReplaceNode(array, identifier, parent),
-                            IAstModification.InsertFirst(vardecl, array.definingScope() as Node)
+                            IAstModification.InsertFirst(vardecl2, array.definingScope() as Node)
                     )
                 }
             }

compiler/src/prog8/ast/processing/AstWalker.kt

@@ -52,7 +52,7 @@ interface IAstModification {
     class InsertAfter(val after: Statement, val stmt: Statement, val parent: Node) : IAstModification {
         override fun perform() {
             if(parent is INameScope) {
-                val idx = parent.statements.indexOf(after)+1
+                val idx = parent.statements.indexOfFirst { it===after } + 1
                 parent.statements.add(idx, stmt)
                 stmt.linkParents(parent)
             } else {
@@ -88,13 +88,12 @@ abstract class AstWalker {
     open fun before(branchStatement: BranchStatement, parent: Node): Iterable<IAstModification> = emptyList()
     open fun before(breakStmt: Break, parent: Node): Iterable<IAstModification> = emptyList()
     open fun before(builtinFunctionStatementPlaceholder: BuiltinFunctionStatementPlaceholder, parent: Node): Iterable<IAstModification> = emptyList()
-    open fun before(contStmt: Continue, parent: Node): Iterable<IAstModification> = emptyList()
     open fun before(decl: VarDecl, parent: Node): Iterable<IAstModification> = emptyList()
     open fun before(directive: Directive, parent: Node): Iterable<IAstModification> = emptyList()
     open fun before(expr: BinaryExpression, parent: Node): Iterable<IAstModification> = emptyList()
     open fun before(expr: PrefixExpression, parent: Node): Iterable<IAstModification> = emptyList()
     open fun before(forLoop: ForLoop, parent: Node): Iterable<IAstModification> = emptyList()
-    open fun before(foreverLoop: ForeverLoop, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(repeatLoop: RepeatLoop, parent: Node): Iterable<IAstModification> = emptyList()
     open fun before(functionCall: FunctionCall, parent: Node): Iterable<IAstModification> = emptyList()
     open fun before(functionCallStatement: FunctionCallStatement, parent: Node): Iterable<IAstModification> = emptyList()
     open fun before(identifier: IdentifierReference, parent: Node): Iterable<IAstModification> = emptyList()
@@ -110,13 +109,11 @@ abstract class AstWalker {
     open fun before(postIncrDecr: PostIncrDecr, parent: Node): Iterable<IAstModification> = emptyList()
     open fun before(program: Program, parent: Node): Iterable<IAstModification> = emptyList()
     open fun before(range: RangeExpr, parent: Node): Iterable<IAstModification> = emptyList()
-    open fun before(registerExpr: RegisterExpr, parent: Node): Iterable<IAstModification> = emptyList()
-    open fun before(repeatLoop: RepeatLoop, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(untilLoop: UntilLoop, parent: Node): Iterable<IAstModification> = emptyList()
     open fun before(returnStmt: Return, parent: Node): Iterable<IAstModification> = emptyList()
     open fun before(scope: AnonymousScope, parent: Node): Iterable<IAstModification> = emptyList()
     open fun before(string: StringLiteralValue, parent: Node): Iterable<IAstModification> = emptyList()
     open fun before(structDecl: StructDecl, parent: Node): Iterable<IAstModification> = emptyList()
-    open fun before(structLv: StructLiteralValue, parent: Node): Iterable<IAstModification> = emptyList()
     open fun before(subroutine: Subroutine, parent: Node): Iterable<IAstModification> = emptyList()
     open fun before(typecast: TypecastExpression, parent: Node): Iterable<IAstModification> = emptyList()
     open fun before(whenChoice: WhenChoice, parent: Node): Iterable<IAstModification> = emptyList()
@@ -132,13 +129,12 @@ abstract class AstWalker {
     open fun after(branchStatement: BranchStatement, parent: Node): Iterable<IAstModification> = emptyList()
     open fun after(breakStmt: Break, parent: Node): Iterable<IAstModification> = emptyList()
     open fun after(builtinFunctionStatementPlaceholder: BuiltinFunctionStatementPlaceholder, parent: Node): Iterable<IAstModification> = emptyList()
-    open fun after(contStmt: Continue, parent: Node): Iterable<IAstModification> = emptyList()
     open fun after(decl: VarDecl, parent: Node): Iterable<IAstModification> = emptyList()
     open fun after(directive: Directive, parent: Node): Iterable<IAstModification> = emptyList()
     open fun after(expr: BinaryExpression, parent: Node): Iterable<IAstModification> = emptyList()
     open fun after(expr: PrefixExpression, parent: Node): Iterable<IAstModification> = emptyList()
     open fun after(forLoop: ForLoop, parent: Node): Iterable<IAstModification> = emptyList()
-    open fun after(foreverLoop: ForeverLoop, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun after(repeatLoop: RepeatLoop, parent: Node): Iterable<IAstModification> = emptyList()
     open fun after(functionCall: FunctionCall, parent: Node): Iterable<IAstModification> = emptyList()
     open fun after(functionCallStatement: FunctionCallStatement, parent: Node): Iterable<IAstModification> = emptyList()
     open fun after(identifier: IdentifierReference, parent: Node): Iterable<IAstModification> = emptyList()
@@ -154,13 +150,11 @@ abstract class AstWalker {
     open fun after(postIncrDecr: PostIncrDecr, parent: Node): Iterable<IAstModification> = emptyList()
     open fun after(program: Program, parent: Node): Iterable<IAstModification> = emptyList()
     open fun after(range: RangeExpr, parent: Node): Iterable<IAstModification> = emptyList()
-    open fun after(registerExpr: RegisterExpr, parent: Node): Iterable<IAstModification> = emptyList()
-    open fun after(repeatLoop: RepeatLoop, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun after(untilLoop: UntilLoop, parent: Node): Iterable<IAstModification> = emptyList()
     open fun after(returnStmt: Return, parent: Node): Iterable<IAstModification> = emptyList()
     open fun after(scope: AnonymousScope, parent: Node): Iterable<IAstModification> = emptyList()
     open fun after(string: StringLiteralValue, parent: Node): Iterable<IAstModification> = emptyList()
     open fun after(structDecl: StructDecl, parent: Node): Iterable<IAstModification> = emptyList()
-    open fun after(structLv: StructLiteralValue, parent: Node): Iterable<IAstModification> = emptyList()
     open fun after(subroutine: Subroutine, parent: Node): Iterable<IAstModification> = emptyList()
     open fun after(typecast: TypecastExpression, parent: Node): Iterable<IAstModification> = emptyList()
     open fun after(whenChoice: WhenChoice, parent: Node): Iterable<IAstModification> = emptyList()
@@ -313,11 +307,6 @@ abstract class AstWalker {
         track(after(postIncrDecr, parent), postIncrDecr, parent)
     }
 
-    fun visit(contStmt: Continue, parent: Node) {
-        track(before(contStmt, parent), contStmt, parent)
-        track(after(contStmt, parent), contStmt, parent)
-    }
-
     fun visit(breakStmt: Break, parent: Node) {
         track(before(breakStmt, parent), breakStmt, parent)
         track(after(breakStmt, parent), breakStmt, parent)
@@ -325,7 +314,7 @@ abstract class AstWalker {
 
     fun visit(forLoop: ForLoop, parent: Node) {
         track(before(forLoop, parent), forLoop, parent)
-        forLoop.loopVar?.accept(this, forLoop)
+        forLoop.loopVar.accept(this, forLoop)
         forLoop.iterable.accept(this, forLoop)
         forLoop.body.accept(this, forLoop)
         track(after(forLoop, parent), forLoop, parent)
@@ -338,19 +327,20 @@ abstract class AstWalker {
         track(after(whileLoop, parent), whileLoop, parent)
     }
 
-    fun visit(foreverLoop: ForeverLoop, parent: Node) {
-        track(before(foreverLoop, parent), foreverLoop, parent)
-        foreverLoop.body.accept(this, foreverLoop)
-        track(after(foreverLoop, parent), foreverLoop, parent)
-    }
-
     fun visit(repeatLoop: RepeatLoop, parent: Node) {
         track(before(repeatLoop, parent), repeatLoop, parent)
-        repeatLoop.untilCondition.accept(this, repeatLoop)
+        repeatLoop.iterations?.accept(this, repeatLoop)
         repeatLoop.body.accept(this, repeatLoop)
         track(after(repeatLoop, parent), repeatLoop, parent)
     }
 
+    fun visit(untilLoop: UntilLoop, parent: Node) {
+        track(before(untilLoop, parent), untilLoop, parent)
+        untilLoop.untilCondition.accept(this, untilLoop)
+        untilLoop.body.accept(this, untilLoop)
+        track(after(untilLoop, parent), untilLoop, parent)
+    }
+
     fun visit(returnStmt: Return, parent: Node) {
         track(before(returnStmt, parent), returnStmt, parent)
         returnStmt.value?.accept(this, returnStmt)
@@ -407,11 +397,6 @@ abstract class AstWalker {
         track(after(inlineAssembly, parent), inlineAssembly, parent)
     }
 
-    fun visit(registerExpr: RegisterExpr, parent: Node) {
-        track(before(registerExpr, parent), registerExpr, parent)
-        track(after(registerExpr, parent), registerExpr, parent)
-    }
-
     fun visit(builtinFunctionStatementPlaceholder: BuiltinFunctionStatementPlaceholder, parent: Node) {
         track(before(builtinFunctionStatementPlaceholder, parent), builtinFunctionStatementPlaceholder, parent)
         track(after(builtinFunctionStatementPlaceholder, parent), builtinFunctionStatementPlaceholder, parent)
@@ -441,11 +426,5 @@ abstract class AstWalker {
         structDecl.statements.forEach { it.accept(this, structDecl) }
         track(after(structDecl, parent), structDecl, parent)
     }
-
-    fun visit(structLv: StructLiteralValue, parent: Node) {
-        track(before(structLv, parent), structLv, parent)
-        structLv.values.forEach { it.accept(this, structLv) }
-        track(after(structLv, parent), structLv, parent)
-    }
 }
 

compiler/src/prog8/ast/processing/IAstVisitor.kt

@@ -95,14 +95,11 @@ interface IAstVisitor {
         postIncrDecr.target.accept(this)
     }
 
-    fun visit(contStmt: Continue) {
-    }
-
     fun visit(breakStmt: Break) {
     }
 
     fun visit(forLoop: ForLoop) {
-        forLoop.loopVar?.accept(this)
+        forLoop.loopVar.accept(this)
         forLoop.iterable.accept(this)
         forLoop.body.accept(this)
     }
@@ -112,13 +109,14 @@ interface IAstVisitor {
         whileLoop.body.accept(this)
     }
 
-    fun visit(foreverLoop: ForeverLoop) {
-        foreverLoop.body.accept(this)
+    fun visit(repeatLoop: RepeatLoop) {
+        repeatLoop.iterations?.accept(this)
+        repeatLoop.body.accept(this)
     }
 
-    fun visit(repeatLoop: RepeatLoop) {
-        repeatLoop.untilCondition.accept(this)
-        repeatLoop.body.accept(this)
+    fun visit(untilLoop: UntilLoop) {
+        untilLoop.untilCondition.accept(this)
+        untilLoop.body.accept(this)
     }
 
     fun visit(returnStmt: Return) {
@@ -159,9 +157,6 @@ interface IAstVisitor {
     fun visit(inlineAssembly: InlineAssembly) {
     }
 
-    fun visit(registerExpr: RegisterExpr) {
-    }
-
     fun visit(builtinFunctionStatementPlaceholder: BuiltinFunctionStatementPlaceholder) {
     }
 
@@ -181,8 +176,4 @@ interface IAstVisitor {
     fun visit(structDecl: StructDecl) {
         structDecl.statements.forEach { it.accept(this) }
     }
-
-    fun visit(structLv: StructLiteralValue) {
-        structLv.values.forEach { it.accept(this) }
-    }
 }

compiler/src/prog8/ast/processing/StatementReorderer.kt

@@ -14,8 +14,8 @@ internal class StatementReorderer(val program: Program) : AstWalker() {
     // - in every scope, most directives and vardecls are moved to the top.
     // - 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) augmented assignment is turned into regular assignment.
     // - (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).
 
@@ -78,8 +78,8 @@ internal class StatementReorderer(val program: Program) : AstWalker() {
             if(declConstValue==null) {
                 // move the vardecl (without value) to the scope and replace this with a regular assignment
                 decl.value = null
-                val target = AssignTarget(null, IdentifierReference(listOf(decl.name), decl.position), null, null, decl.position)
-                val assign = Assignment(target, null, declValue, decl.position)
+                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() as Node)
@@ -99,15 +99,11 @@ internal class StatementReorderer(val program: Program) : AstWalker() {
     }
 
     override fun before(assignment: Assignment, parent: Node): Iterable<IAstModification> {
-        if(assignment.aug_op!=null) {
-            return listOf(IAstModification.ReplaceNode(assignment, assignment.asDesugaredNonaugmented(), parent))
-        }
-
         val valueType = assignment.value.inferType(program)
         val targetType = assignment.target.inferType(program, assignment)
         if(valueType.istype(DataType.STRUCT) && targetType.istype(DataType.STRUCT)) {
-            val assignments = if (assignment.value is StructLiteralValue) {
-                flattenStructAssignmentFromStructLiteral(assignment, program)    //  'structvar = { ..... } '
+            val assignments = if (assignment.value is ArrayLiteralValue) {
+                flattenStructAssignmentFromStructLiteral(assignment, program)    //  'structvar = [ ..... ] '
             } else {
                 flattenStructAssignmentFromIdentifier(assignment, program)    //   'structvar1 = structvar2'
             }
@@ -122,22 +118,71 @@ internal class StatementReorderer(val program: Program) : AstWalker() {
         return noModifications
     }
 
+    override fun after(assignment: Assignment, parent: Node): Iterable<IAstModification> {
+        // rewrite in-place assignment expressions a bit so that the assignment target usually is the leftmost operand
+        val binExpr = assignment.value as? BinaryExpression
+        if(binExpr!=null) {
+            if(binExpr.left isSameAs assignment.target) {
+                // A = A <operator> 5, unchanged
+                return noModifications
+            }
+
+            if(binExpr.operator in associativeOperators) {
+                if (binExpr.right isSameAs assignment.target) {
+                    // A = v <associative-operator> A  ==>  A = A <associative-operator> v
+                    return listOf(IAstModification.SwapOperands(binExpr))
+                }
+
+                val leftBinExpr = binExpr.left as? BinaryExpression
+                if(leftBinExpr?.operator == binExpr.operator) {
+                    return if(leftBinExpr.left isSameAs assignment.target) {
+                        // A = (A <associative-operator> x) <same-operator> y ==> A = A <associative-operator> (x <same-operator> y)
+                        val newRight = BinaryExpression(leftBinExpr.right, binExpr.operator, binExpr.right, binExpr.position)
+                        val newValue = BinaryExpression(leftBinExpr.left, binExpr.operator, newRight, binExpr.position)
+                        listOf(IAstModification.ReplaceNode(binExpr, newValue, assignment))
+                    } else {
+                        // A = (x <associative-operator> A) <same-operator> y ==> A = A <associative-operator> (x <same-operator> y)
+                        val newRight = BinaryExpression(leftBinExpr.left, binExpr.operator, binExpr.right, binExpr.position)
+                        val newValue = BinaryExpression(leftBinExpr.right, binExpr.operator, newRight, binExpr.position)
+                        listOf(IAstModification.ReplaceNode(binExpr, newValue, assignment))
+                    }
+                }
+                val rightBinExpr = binExpr.right as? BinaryExpression
+                if(rightBinExpr?.operator == binExpr.operator) {
+                    return if(rightBinExpr.left isSameAs assignment.target) {
+                        // A = x <associative-operator> (A <same-operator> y) ==> A = A <associative-operator> (x <same-operator> y)
+                        val newRight = BinaryExpression(binExpr.left, binExpr.operator, rightBinExpr.right, binExpr.position)
+                        val newValue = BinaryExpression(rightBinExpr.left, binExpr.operator, newRight, binExpr.position)
+                        listOf(IAstModification.ReplaceNode(binExpr, newValue, assignment))
+                    } else {
+                        // A = x <associative-operator> (y <same-operator> A) ==> A = A <associative-operator> (x <same-operator> y)
+                        val newRight = BinaryExpression(binExpr.left, binExpr.operator, rightBinExpr.left, binExpr.position)
+                        val newValue = BinaryExpression(rightBinExpr.right, binExpr.operator, newRight, binExpr.position)
+                        listOf(IAstModification.ReplaceNode(binExpr, newValue, assignment))
+                    }
+                }
+            }
+        }
+
+        return noModifications
+    }
+
     private fun flattenStructAssignmentFromStructLiteral(structAssignment: Assignment, program: Program): List<Assignment> {
         val identifier = structAssignment.target.identifier!!
         val identifierName = identifier.nameInSource.single()
         val targetVar = identifier.targetVarDecl(program.namespace)!!
         val struct = targetVar.struct!!
 
-        val slv = structAssignment.value as? StructLiteralValue
-        if(slv==null || slv.values.size != struct.numberOfElements)
+        val slv = structAssignment.value as? ArrayLiteralValue
+        if(slv==null || slv.value.size != struct.numberOfElements)
             throw FatalAstException("element count mismatch")
 
-        return struct.statements.zip(slv.values).map { (targetDecl, sourceValue) ->
+        return struct.statements.zip(slv.value).map { (targetDecl, sourceValue) ->
             targetDecl as VarDecl
             val mangled = mangledStructMemberName(identifierName, targetDecl.name)
             val idref = IdentifierReference(listOf(mangled), structAssignment.position)
-            val assign = Assignment(AssignTarget(null, idref, null, null, structAssignment.position),
-                    null, sourceValue, sourceValue.position)
+            val assign = Assignment(AssignTarget(idref, null, null, structAssignment.position),
+                    sourceValue, sourceValue.position)
             assign.linkParents(structAssignment)
             assign
         }
@@ -168,13 +213,12 @@ internal class StatementReorderer(val program: Program) : AstWalker() {
                     val idref = IdentifierReference(listOf(mangled), structAssignment.position)
                     val sourcemangled = mangledStructMemberName(sourceVar.name, sourceDecl.name)
                     val sourceIdref = IdentifierReference(listOf(sourcemangled), structAssignment.position)
-                    val assign = Assignment(AssignTarget(null, idref, null, null, structAssignment.position),
-                            null, sourceIdref, member.second.position)
+                    val assign = Assignment(AssignTarget(idref, null, null, structAssignment.position), sourceIdref, member.second.position)
                     assign.linkParents(structAssignment)
                     assign
                 }
             }
-            is StructLiteralValue -> {
+            is ArrayLiteralValue -> {
                 throw IllegalArgumentException("not going to flatten a structLv assignment here")
             }
             else -> throw FatalAstException("strange struct value")

compiler/src/prog8/ast/processing/TypecastsAdder.kt

@@ -52,7 +52,7 @@ class TypecastsAdder(val program: Program, val errors: ErrorReporter) : AstWalke
                             assignment))
                 } else {
                     fun castLiteral(cvalue: NumericLiteralValue): List<IAstModification.ReplaceNode> =
-                        listOf(IAstModification.ReplaceNode(cvalue, cvalue.cast(targettype), cvalue.parent))
+                        listOf(IAstModification.ReplaceNode(cvalue, cvalue.castNoCheck(targettype), cvalue.parent))
                     val cvalue = assignment.value.constValue(program)
                     if(cvalue!=null) {
                         val number = cvalue.number.toDouble()
@@ -87,7 +87,9 @@ class TypecastsAdder(val program: Program, val errors: ErrorReporter) : AstWalke
 
     private fun afterFunctionCallArgs(call: IFunctionCall, scope: INameScope): Iterable<IAstModification> {
         // see if a typecast is needed to convert the arguments into the required parameter's type
-        return when(val sub = call.target.targetStatement(scope)) {
+        val modifications = mutableListOf<IAstModification>()
+
+        when(val sub = call.target.targetStatement(scope)) {
             is Subroutine -> {
                 for(arg in sub.parameters.zip(call.args.withIndex())) {
                     val argItype = arg.second.value.inferType(program)
@@ -96,48 +98,57 @@ class TypecastsAdder(val program: Program, val errors: ErrorReporter) : AstWalke
                         val requiredType = arg.first.type
                         if (requiredType != argtype) {
                             if (argtype isAssignableTo requiredType) {
-                                return listOf(IAstModification.ReplaceNode(
+                                modifications += IAstModification.ReplaceNode(
                                         call.args[arg.second.index],
                                         TypecastExpression(arg.second.value, requiredType, true, arg.second.value.position),
-                                        call as Node))
+                                        call as Node)
                             } else if(requiredType == DataType.UWORD && argtype in PassByReferenceDatatypes) {
                                 // we allow STR/ARRAY values in place of UWORD parameters. Take their address instead.
-                                return listOf(IAstModification.ReplaceNode(
+                                modifications += IAstModification.ReplaceNode(
                                         call.args[arg.second.index],
                                         AddressOf(arg.second.value as IdentifierReference, arg.second.value.position),
-                                        call as Node))
-                            }
-                        }
-                    }
-                }
-                emptyList()
-            }
-            is BuiltinFunctionStatementPlaceholder -> {
-                val func = BuiltinFunctions.getValue(sub.name)
-                if(func.pure) {
-                    // non-pure functions don't get automatic typecasts because sometimes they act directly on their parameters
-                    for (arg in func.parameters.zip(call.args.withIndex())) {
-                        val argItype = arg.second.value.inferType(program)
-                        if (argItype.isKnown) {
-                            val argtype = argItype.typeOrElse(DataType.STRUCT)
-                            if (arg.first.possibleDatatypes.any { argtype == it })
-                                continue
-                            for (possibleType in arg.first.possibleDatatypes) {
-                                if (argtype isAssignableTo possibleType) {
-                                    return listOf(IAstModification.ReplaceNode(
-                                            call.args[arg.second.index],
-                                            TypecastExpression(arg.second.value, possibleType, true, arg.second.value.position),
-                                            call as Node))
+                                        call as Node)
+                            } else if(arg.second.value is NumericLiteralValue) {
+                                if(argtype.isAssignableTo(requiredType)) {
+                                    try {
+                                        val castedValue = (arg.second.value as NumericLiteralValue).castNoCheck(requiredType)
+                                        modifications += IAstModification.ReplaceNode(
+                                                call.args[arg.second.index],
+                                                castedValue,
+                                                call as Node)
+                                    } catch (x: ExpressionError) {
+                                        // cast failed
+                                    }
                                 }
                             }
                         }
                     }
                 }
-                emptyList()
             }
-            null -> emptyList()
+            is BuiltinFunctionStatementPlaceholder -> {
+                val func = BuiltinFunctions.getValue(sub.name)
+                for (arg in func.parameters.zip(call.args.withIndex())) {
+                    val argItype = arg.second.value.inferType(program)
+                    if (argItype.isKnown) {
+                        val argtype = argItype.typeOrElse(DataType.STRUCT)
+                        if (arg.first.possibleDatatypes.any { argtype == it })
+                            continue
+                        for (possibleType in arg.first.possibleDatatypes) {
+                            if (argtype isAssignableTo possibleType) {
+                                modifications += IAstModification.ReplaceNode(
+                                        call.args[arg.second.index],
+                                        TypecastExpression(arg.second.value, possibleType, true, arg.second.value.position),
+                                        call as Node)
+                            }
+                        }
+                    }
+                }
+            }
+            null -> { }
             else -> throw FatalAstException("call to something weird $sub   ${call.target}")
         }
+
+        return modifications
     }
 
     override fun after(typecast: TypecastExpression, parent: Node): Iterable<IAstModification> {
@@ -152,7 +163,7 @@ class TypecastsAdder(val program: Program, val errors: ErrorReporter) : AstWalke
         // make sure the memory address is an uword
         val dt = memread.addressExpression.inferType(program)
         if(dt.isKnown && dt.typeOrElse(DataType.UWORD)!=DataType.UWORD) {
-            val typecast = (memread.addressExpression as? NumericLiteralValue)?.cast(DataType.UWORD)
+            val typecast = (memread.addressExpression as? NumericLiteralValue)?.castNoCheck(DataType.UWORD)
                     ?: TypecastExpression(memread.addressExpression, DataType.UWORD, true, memread.addressExpression.position)
             return listOf(IAstModification.ReplaceNode(memread.addressExpression, typecast, memread))
         }
@@ -163,58 +174,13 @@ class TypecastsAdder(val program: Program, val errors: ErrorReporter) : AstWalke
         // make sure the memory address is an uword
         val dt = memwrite.addressExpression.inferType(program)
         if(dt.isKnown && dt.typeOrElse(DataType.UWORD)!=DataType.UWORD) {
-            val typecast = (memwrite.addressExpression as? NumericLiteralValue)?.cast(DataType.UWORD)
+            val typecast = (memwrite.addressExpression as? NumericLiteralValue)?.castNoCheck(DataType.UWORD)
                     ?: TypecastExpression(memwrite.addressExpression, DataType.UWORD, true, memwrite.addressExpression.position)
             return listOf(IAstModification.ReplaceNode(memwrite.addressExpression, typecast, memwrite))
         }
         return noModifications
     }
 
-    override fun after(structLv: StructLiteralValue, parent: Node): Iterable<IAstModification> {
-        // assignment of a struct literal value, some member values may need proper typecast
-
-        fun addTypecastsIfNeeded(struct: StructDecl): Iterable<IAstModification> {
-            val newValues = struct.statements.zip(structLv.values).map { (structMemberDecl, memberValue) ->
-                val memberDt = (structMemberDecl as VarDecl).datatype
-                val valueDt = memberValue.inferType(program)
-                if (valueDt.typeOrElse(memberDt) != memberDt)
-                    TypecastExpression(memberValue, memberDt, true, memberValue.position)
-                else
-                    memberValue
-            }
-
-            class StructLvValueReplacer(val targetStructLv: StructLiteralValue, val typecastValues: List<Expression>) : IAstModification {
-                override fun perform() {
-                    targetStructLv.values = typecastValues
-                    typecastValues.forEach { it.linkParents(targetStructLv) }
-                }
-            }
-
-            return if(structLv.values.zip(newValues).any { (v1, v2) -> v1 !== v2})
-                listOf(StructLvValueReplacer(structLv, newValues))
-            else
-                emptyList()
-        }
-
-        val decl = structLv.parent as? VarDecl
-        if(decl != null) {
-            val struct = decl.struct
-            if(struct != null)
-                return addTypecastsIfNeeded(struct)
-        } else {
-            val assign = structLv.parent as? Assignment
-            if (assign != null) {
-                val decl2 = assign.target.identifier?.targetVarDecl(program.namespace)
-                if(decl2 != null) {
-                    val struct = decl2.struct
-                    if(struct != null)
-                        return addTypecastsIfNeeded(struct)
-                }
-            }
-        }
-        return noModifications
-    }
-
     override fun after(returnStmt: Return, parent: Node): Iterable<IAstModification> {
         // add a typecast to the return type if it doesn't match the subroutine's signature
         val returnValue = returnStmt.value
@@ -225,7 +191,7 @@ class TypecastsAdder(val program: Program, val errors: ErrorReporter) : AstWalke
                 if (returnValue.inferType(program).istype(subReturnType))
                     return noModifications
                 if (returnValue is NumericLiteralValue) {
-                    returnStmt.value = returnValue.cast(subroutine.returntypes.single())
+                    returnStmt.value = returnValue.castNoCheck(subroutine.returntypes.single())
                 } else {
                     return listOf(IAstModification.ReplaceNode(
                             returnValue,

compiler/src/prog8/ast/processing/VariousCleanups.kt

@@ -0,0 +1,43 @@
+package prog8.ast.processing
+
+import prog8.ast.INameScope
+import prog8.ast.Node
+import prog8.ast.expressions.NumericLiteralValue
+import prog8.ast.expressions.TypecastExpression
+import prog8.ast.statements.AnonymousScope
+import prog8.ast.statements.NopStatement
+
+
+internal class VariousCleanups: AstWalker() {
+    private val noModifications = emptyList<IAstModification>()
+
+    override fun before(nopStatement: NopStatement, parent: Node): Iterable<IAstModification> {
+        return listOf(IAstModification.Remove(nopStatement, parent))
+    }
+
+    override fun before(scope: AnonymousScope, parent: Node): Iterable<IAstModification> {
+        return if(parent is INameScope)
+            listOf(ScopeFlatten(scope, parent as INameScope))
+        else
+            noModifications
+    }
+
+    class ScopeFlatten(val scope: AnonymousScope, val into: INameScope) : IAstModification {
+        override fun perform() {
+            val idx = into.statements.indexOf(scope)
+            if(idx>=0) {
+                into.statements.addAll(idx+1, scope.statements)
+                into.statements.remove(scope)
+            }
+        }
+    }
+
+    override fun before(typecast: TypecastExpression, parent: Node): Iterable<IAstModification> {
+        if(typecast.expression is NumericLiteralValue) {
+            val value = (typecast.expression as NumericLiteralValue).castNoCheck(typecast.type)
+            return listOf(IAstModification.ReplaceNode(typecast, value, parent))
+        }
+
+        return noModifications
+    }
+}

compiler/src/prog8/ast/processing/VerifyFunctionArgTypes.kt

@@ -0,0 +1,61 @@
+package prog8.ast.processing
+
+import prog8.ast.IFunctionCall
+import prog8.ast.INameScope
+import prog8.ast.Program
+import prog8.ast.base.DataType
+import prog8.ast.expressions.FunctionCall
+import prog8.ast.statements.BuiltinFunctionStatementPlaceholder
+import prog8.ast.statements.FunctionCallStatement
+import prog8.ast.statements.Subroutine
+import prog8.compiler.CompilerException
+import prog8.functions.BuiltinFunctions
+
+class VerifyFunctionArgTypes(val program: Program) : IAstVisitor {
+
+    override fun visit(functionCall: FunctionCall) {
+        val error = checkTypes(functionCall as IFunctionCall, functionCall.definingScope(), program)
+        if(error!=null)
+            throw CompilerException(error)
+    }
+
+    override fun visit(functionCallStatement: FunctionCallStatement) {
+        val error = checkTypes(functionCallStatement as IFunctionCall, functionCallStatement.definingScope(), program)
+        if (error!=null)
+            throw CompilerException(error)
+    }
+
+    companion object {
+        fun checkTypes(call: IFunctionCall, scope: INameScope, program: Program): String? {
+            val argtypes = call.args.map { it.inferType(program).typeOrElse(DataType.STRUCT) }
+            val target = call.target.targetStatement(scope)
+            if (target is Subroutine) {
+                // asmsub types are not checked specifically at this time
+                if(call.args.size != target.parameters.size)
+                    return "invalid number of arguments"
+                val paramtypes = target.parameters.map { it.type }
+                val mismatch = argtypes.zip(paramtypes).indexOfFirst { it.first != it.second}
+                if(mismatch>=0) {
+                    val actual = argtypes[mismatch].toString()
+                    val expected = paramtypes[mismatch].toString()
+                    return "argument ${mismatch + 1} type mismatch, was: $actual expected: $expected"
+                }
+            }
+            else if (target is BuiltinFunctionStatementPlaceholder) {
+                val func = BuiltinFunctions.getValue(target.name)
+                if(call.args.size != func.parameters.size)
+                    return "invalid number of arguments"
+                val paramtypes = func.parameters.map { it.possibleDatatypes }
+                for (x in argtypes.zip(paramtypes).withIndex()) {
+                    if (x.value.first !in x.value.second) {
+                        val actual = x.value.first.toString()
+                        val expected = x.value.second.toString()
+                        return "argument ${x.index + 1} type mismatch, was: $actual expected: $expected"
+                    }
+                }
+            }
+
+            return null
+        }
+    }
+}

compiler/src/prog8/ast/statements/AstStatements.kt

@@ -29,8 +29,6 @@ sealed class Statement : Node {
         return scope.joinToString(".")
     }
 
-    abstract val expensiveToInline: Boolean
-
     fun definingBlock(): Block {
         if(this is Block)
             return this
@@ -48,7 +46,6 @@ class BuiltinFunctionStatementPlaceholder(val name: String, override val positio
     override fun replaceChildNode(node: Node, replacement: Node) {
         replacement.parent = this
     }
-    override val expensiveToInline = false
 }
 
 data class RegisterOrStatusflag(val registerOrPair: RegisterOrPair?, val statusflag: Statusflag?, val stack: Boolean)
@@ -59,8 +56,6 @@ class Block(override val name: String,
             val isInLibrary: Boolean,
             override val position: Position) : Statement(), INameScope {
     override lateinit var parent: Node
-    override val expensiveToInline
-        get() = statements.any { it.expensiveToInline }
 
     override fun linkParents(parent: Node) {
         this.parent = parent
@@ -69,7 +64,7 @@ class Block(override val name: String,
 
     override fun replaceChildNode(node: Node, replacement: Node) {
         require(replacement is Statement)
-        val idx = statements.indexOf(node)
+        val idx = statements.indexOfFirst { it ===node }
         statements[idx] = replacement
         replacement.parent = this
     }
@@ -86,7 +81,6 @@ class Block(override val name: String,
 
 data class Directive(val directive: String, val args: List<DirectiveArg>, override val position: Position) : Statement() {
     override lateinit var parent: Node
-    override val expensiveToInline = false
 
     override fun linkParents(parent: Node) {
         this.parent = parent
@@ -109,7 +103,6 @@ data class DirectiveArg(val str: String?, val name: String?, val int: Int?, over
 
 data class Label(val name: String, override val position: Position) : Statement() {
     override lateinit var parent: Node
-    override val expensiveToInline = false
 
     override fun linkParents(parent: Node) {
         this.parent = parent
@@ -126,7 +119,6 @@ data class Label(val name: String, override val position: Position) : Statement(
 
 open class Return(var value: Expression?, override val position: Position) : Statement() {
     override lateinit var parent: Node
-    override val expensiveToInline = value!=null && value !is NumericLiteralValue
 
     override fun linkParents(parent: Node) {
         this.parent = parent
@@ -147,31 +139,8 @@ open class Return(var value: Expression?, override val position: Position) : Sta
     }
 }
 
-class ReturnFromIrq(override val position: Position) : Return(null, position) {
-    override fun accept(visitor: IAstVisitor) = visitor.visit(this)
-
-    override fun toString(): String {
-        return "ReturnFromIrq(pos=$position)"
-    }
-    override fun replaceChildNode(node: Node, replacement: Node) = throw FatalAstException("can't replace here")
-}
-
-class Continue(override val position: Position) : Statement() {
-    override lateinit var parent: Node
-    override val expensiveToInline = false
-
-    override fun linkParents(parent: Node) {
-        this.parent=parent
-    }
-
-    override fun replaceChildNode(node: Node, replacement: Node) = throw FatalAstException("can't replace here")
-    override fun accept(visitor: IAstVisitor) = visitor.visit(this)
-    override fun accept(visitor: AstWalker, parent: Node) = visitor.visit(this, parent)
-}
-
 class Break(override val position: Position) : Statement() {
     override lateinit var parent: Node
-    override val expensiveToInline = false
 
     override fun linkParents(parent: Node) {
         this.parent=parent
@@ -207,9 +176,6 @@ open class VarDecl(val type: VarDeclType,
     var structHasBeenFlattened = false      // set later
         private set
 
-    override val expensiveToInline
-            get() = value!=null && value !is NumericLiteralValue
-
     // prefix for literal values that are turned into a variable on the heap
 
     companion object {
@@ -283,7 +249,7 @@ open class VarDecl(val type: VarDeclType,
     fun flattenStructMembers(): MutableList<Statement> {
         val result = struct!!.statements.withIndex().map {
             val member = it.value as VarDecl
-            val initvalue = if(value!=null) (value as StructLiteralValue).values[it.index] else null
+            val initvalue = if(value!=null) (value as ArrayLiteralValue).value[it.index] else null
             VarDecl(
                     VarDeclType.VAR,
                     member.datatype,
@@ -337,10 +303,8 @@ class ArrayIndex(var index: Expression, override val position: Position) : Node
     fun size() = (index as? NumericLiteralValue)?.number?.toInt()
 }
 
-open class Assignment(var target: AssignTarget, var aug_op : String?, var value: Expression, override val position: Position) : Statement() {
+open class Assignment(var target: AssignTarget, var value: Expression, override val position: Position) : Statement() {
     override lateinit var parent: Node
-    override val expensiveToInline
-            get() = value !is NumericLiteralValue
 
     override fun linkParents(parent: Node) {
         this.parent = parent
@@ -361,36 +325,58 @@ open class Assignment(var target: AssignTarget, var aug_op : String?, var value:
     override fun accept(visitor: AstWalker, parent: Node) = visitor.visit(this, parent)
 
     override fun toString(): String {
-        return("Assignment(augop: $aug_op, target: $target, value: $value, pos=$position)")
+        return("Assignment(target: $target, value: $value, pos=$position)")
     }
 
-    fun asDesugaredNonaugmented(): Assignment {
-        val augmented = aug_op ?: return this
+    /**
+     * Is the assigment value an expression that references the assignment target itself?
+     * The expression can be a BinaryExpression, PrefixExpression or TypecastExpression (possibly with one sub-cast).
+     */
+    val isAugmentable: Boolean
+        get() {
+            val binExpr = value as? BinaryExpression
+            if(binExpr!=null) {
+                if(binExpr.right !is BinaryExpression && binExpr.left isSameAs target)
+                    return true  // A = A <operator> v
 
-        val leftOperand: Expression =
-                when {
-                    target.register != null -> RegisterExpr(target.register!!, target.position)
-                    target.identifier != null -> target.identifier!!
-                    target.arrayindexed != null -> target.arrayindexed!!
-                    target.memoryAddress != null -> DirectMemoryRead(target.memoryAddress!!.addressExpression, value.position)
-                    else -> throw FatalAstException("strange this")
+                if(binExpr.operator in associativeOperators) {
+                    if (binExpr.left !is BinaryExpression && binExpr.right isSameAs target)
+                        return true  // A = v <associative-operator> A
+
+                    val leftBinExpr = binExpr.left as? BinaryExpression
+                    if(leftBinExpr?.operator == binExpr.operator) {
+                        // one of these?
+                        // A = (A <associative-operator> x) <same-operator> y
+                        // A = (x <associative-operator> A) <same-operator> y
+                        // A = (x <associative-operator> y) <same-operator> A
+                        return leftBinExpr.left isSameAs target || leftBinExpr.right isSameAs target || binExpr.right isSameAs target
+                    }
+                    val rightBinExpr = binExpr.right as? BinaryExpression
+                    if(rightBinExpr?.operator == binExpr.operator) {
+                        // one of these?
+                        // A = y <associative-operator> (A <same-operator> x)
+                        // A = y <associative-operator> (x <same-operator> y)
+                        // A = A <associative-operator> (x <same-operator> y)
+                        return rightBinExpr.left isSameAs target || rightBinExpr.right isSameAs target || binExpr.left isSameAs target
+                    }
                 }
-
-        val assignment =
-            if(augmented=="setvalue") {
-                Assignment(target, null, value, position)
-            } else {
-                val expression = BinaryExpression(leftOperand, augmented.substringBeforeLast('='), value, position)
-                Assignment(target, null, expression, position)
             }
-        assignment.linkParents(parent)
 
-        return assignment
-    }
+            val prefixExpr = value as? PrefixExpression
+            if(prefixExpr!=null)
+                return prefixExpr.expression isSameAs target
+
+            val castExpr = value as? TypecastExpression
+            if(castExpr!=null) {
+                val subCast = castExpr.expression as? TypecastExpression
+                return if(subCast!=null) subCast.expression isSameAs target else castExpr.expression isSameAs target
+            }
+
+            return false
+        }
 }
 
-data class AssignTarget(val register: Register?,
-                        var identifier: IdentifierReference?,
+data class AssignTarget(var identifier: IdentifierReference?,
                         var arrayindexed: ArrayIndexedExpression?,
                         val memoryAddress: DirectMemoryWrite?,
                         override val position: Position) : Node {
@@ -418,19 +404,15 @@ data class AssignTarget(val register: Register?,
     companion object {
         fun fromExpr(expr: Expression): AssignTarget {
             return when (expr) {
-                is RegisterExpr -> AssignTarget(expr.register, null, null, null, expr.position)
-                is IdentifierReference -> AssignTarget(null, expr, null, null, expr.position)
-                is ArrayIndexedExpression -> AssignTarget(null, null, expr, null, expr.position)
-                is DirectMemoryRead -> AssignTarget(null, null, null, DirectMemoryWrite(expr.addressExpression, expr.position), expr.position)
+                is IdentifierReference -> AssignTarget(expr, null, null, expr.position)
+                is ArrayIndexedExpression -> AssignTarget(null, expr, null, expr.position)
+                is DirectMemoryRead -> AssignTarget(null, null, DirectMemoryWrite(expr.addressExpression, expr.position), expr.position)
                 else -> throw FatalAstException("invalid expression object $expr")
             }
         }
     }
 
     fun inferType(program: Program, stmt: Statement): InferredTypes.InferredType {
-        if(register!=null)
-            return InferredTypes.knownFor(DataType.UBYTE)
-
         if(identifier!=null) {
             val symbol = program.namespace.lookup(identifier!!.nameInSource, stmt) ?: return InferredTypes.unknown()
             if (symbol is VarDecl) return InferredTypes.knownFor(symbol.datatype)
@@ -446,6 +428,15 @@ data class AssignTarget(val register: Register?,
         return InferredTypes.unknown()
     }
 
+    fun toExpression(): Expression {
+        return when {
+            identifier!=null -> identifier!!
+            arrayindexed!=null -> arrayindexed!!
+            memoryAddress!=null -> DirectMemoryRead(memoryAddress.addressExpression, memoryAddress.position)
+            else -> throw FatalAstException("invalid assignmenttarget $this")
+        }
+    }
+
     infix fun isSameAs(value: Expression): Boolean {
         return when {
             this.memoryAddress!=null -> {
@@ -455,7 +446,6 @@ data class AssignTarget(val register: Register?,
                 else
                     false
             }
-            this.register!=null -> value is RegisterExpr && value.register==register
             this.identifier!=null -> value is IdentifierReference && value.nameInSource==identifier!!.nameInSource
             this.arrayindexed!=null -> value is ArrayIndexedExpression &&
                     value.identifier.nameInSource==arrayindexed!!.identifier.nameInSource &&
@@ -469,8 +459,6 @@ data class AssignTarget(val register: Register?,
     fun isSameAs(other: AssignTarget, program: Program): Boolean {
         if(this===other)
             return true
-        if(this.register!=null && other.register!=null)
-            return this.register==other.register
         if(this.identifier!=null && other.identifier!=null)
             return this.identifier!!.nameInSource==other.identifier!!.nameInSource
         if(this.memoryAddress!=null && other.memoryAddress!=null) {
@@ -489,8 +477,6 @@ data class AssignTarget(val register: Register?,
     }
 
     fun isNotMemory(namespace: INameScope): Boolean {
-        if(this.register!=null)
-            return true
         if(this.memoryAddress!=null)
             return false
         if(this.arrayindexed!=null) {
@@ -509,7 +495,6 @@ data class AssignTarget(val register: Register?,
 
 class PostIncrDecr(var target: AssignTarget, val operator: String, override val position: Position) : Statement() {
     override lateinit var parent: Node
-    override val expensiveToInline = false
 
     override fun linkParents(parent: Node) {
         this.parent = parent
@@ -535,7 +520,6 @@ class Jump(val address: Int?,
            val generatedLabel: String?,             // used in code generation scenarios
            override val position: Position) : Statement() {
     override lateinit var parent: Node
-    override val expensiveToInline = false
 
     override fun linkParents(parent: Node) {
         this.parent = parent
@@ -556,8 +540,6 @@ class FunctionCallStatement(override var target: IdentifierReference,
                             val void: Boolean,
                             override val position: Position) : Statement(), IFunctionCall {
     override lateinit var parent: Node
-    override val expensiveToInline
-            get() = args.any { it !is NumericLiteralValue }
 
     override fun linkParents(parent: Node) {
         this.parent = parent
@@ -569,7 +551,7 @@ class FunctionCallStatement(override var target: IdentifierReference,
         if(node===target)
             target = replacement as IdentifierReference
         else {
-            val idx = args.indexOf(node)
+            val idx = args.indexOfFirst { it===node }
             args[idx] = replacement as Expression
         }
         replacement.parent = this
@@ -585,7 +567,6 @@ class FunctionCallStatement(override var target: IdentifierReference,
 
 class InlineAssembly(val assembly: String, override val position: Position) : Statement() {
     override lateinit var parent: Node
-    override val expensiveToInline = true
 
     override fun linkParents(parent: Node) {
         this.parent = parent
@@ -600,8 +581,6 @@ class AnonymousScope(override var statements: MutableList<Statement>,
                      override val position: Position) : INameScope, Statement() {
     override val name: String
     override lateinit var parent: Node
-    override val expensiveToInline
-        get() = statements.any { it.expensiveToInline }
 
     companion object {
         private var sequenceNumber = 1
@@ -619,7 +598,7 @@ class AnonymousScope(override var statements: MutableList<Statement>,
 
     override fun replaceChildNode(node: Node, replacement: Node) {
         require(replacement is Statement)
-        val idx = statements.indexOf(node)
+        val idx = statements.indexOfFirst { it===node }
         statements[idx] = replacement
         replacement.parent = this
     }
@@ -630,7 +609,6 @@ class AnonymousScope(override var statements: MutableList<Statement>,
 
 class NopStatement(override val position: Position): Statement() {
     override lateinit var parent: Node
-    override val expensiveToInline = false
 
     override fun linkParents(parent: Node) {
         this.parent = parent
@@ -639,14 +617,6 @@ class NopStatement(override val position: Position): Statement() {
     override fun replaceChildNode(node: Node, replacement: Node) = throw FatalAstException("can't replace here")
     override fun accept(visitor: IAstVisitor) = visitor.visit(this)
     override fun accept(visitor: AstWalker, parent: Node) = visitor.visit(this, parent)
-
-    companion object {
-        fun insteadOf(stmt: Statement): NopStatement {
-            val nop = NopStatement(stmt.position)
-            nop.parent = stmt.parent
-            return nop
-        }
-    }
 }
 
 // the subroutine class covers both the normal user-defined subroutines,
@@ -657,20 +627,13 @@ class Subroutine(override val name: String,
                  val returntypes: List<DataType>,
                  val asmParameterRegisters: List<RegisterOrStatusflag>,
                  val asmReturnvaluesRegisters: List<RegisterOrStatusflag>,
-                 val asmClobbers: Set<Register>,
+                 val asmClobbers: Set<CpuRegister>,
                  val asmAddress: Int?,
                  val isAsmSubroutine: Boolean,
                  override var statements: MutableList<Statement>,
                  override val position: Position) : Statement(), INameScope {
 
-    var keepAlways: Boolean = false
-    override val expensiveToInline
-            get() = statements.any { it.expensiveToInline }
-
     override lateinit var parent: Node
-    val calledBy = mutableListOf<Node>()
-    val calls = mutableSetOf<Subroutine>()
-
     val scopedname: String by lazy { makeScopedName(name) }
 
     override fun linkParents(parent: Node) {
@@ -681,7 +644,7 @@ class Subroutine(override val name: String,
 
     override fun replaceChildNode(node: Node, replacement: Node) {
         require(replacement is Statement)
-        val idx = statements.indexOf(node)
+        val idx = statements.indexOfFirst { it===node }
         statements[idx] = replacement
         replacement.parent = this
     }
@@ -722,8 +685,6 @@ class IfStatement(var condition: Expression,
                   var elsepart: AnonymousScope,
                   override val position: Position) : Statement() {
     override lateinit var parent: Node
-    override val expensiveToInline: Boolean
-        get() = truepart.expensiveToInline || elsepart.expensiveToInline
 
     override fun linkParents(parent: Node) {
         this.parent = parent
@@ -752,8 +713,6 @@ class BranchStatement(var condition: BranchCondition,
                       var elsepart: AnonymousScope,
                       override val position: Position) : Statement() {
     override lateinit var parent: Node
-    override val expensiveToInline: Boolean
-        get() = truepart.expensiveToInline || elsepart.expensiveToInline
 
     override fun linkParents(parent: Node) {
         this.parent = parent
@@ -775,17 +734,15 @@ class BranchStatement(var condition: BranchCondition,
 
 }
 
-class ForLoop(val loopRegister: Register?,
-              var loopVar: IdentifierReference?,
+class ForLoop(var loopVar: IdentifierReference,
               var iterable: Expression,
               var body: AnonymousScope,
               override val position: Position) : Statement() {
     override lateinit var parent: Node
-    override val expensiveToInline = true
 
     override fun linkParents(parent: Node) {
         this.parent=parent
-        loopVar?.linkParents(this)
+        loopVar.linkParents(this)
         iterable.linkParents(this)
         body.linkParents(this)
     }
@@ -804,21 +761,16 @@ class ForLoop(val loopRegister: Register?,
     override fun accept(visitor: AstWalker, parent: Node) = visitor.visit(this, parent)
 
     override fun toString(): String {
-        return "ForLoop(loopVar: $loopVar, loopReg: $loopRegister, iterable: $iterable, pos=$position)"
+        return "ForLoop(loopVar: $loopVar, iterable: $iterable, pos=$position)"
     }
 
-    fun loopVarDt(program: Program): InferredTypes.InferredType {
-        val lv = loopVar
-        return if(loopRegister!=null) InferredTypes.InferredType.known(DataType.UBYTE)
-                else lv?.inferType(program) ?: InferredTypes.InferredType.unknown()
-    }
+    fun loopVarDt(program: Program) = loopVar.inferType(program)
 }
 
 class WhileLoop(var condition: Expression,
                 var body: AnonymousScope,
                 override val position: Position) : Statement() {
     override lateinit var parent: Node
-    override val expensiveToInline = true
 
     override fun linkParents(parent: Node) {
         this.parent = parent
@@ -839,18 +791,21 @@ class WhileLoop(var condition: Expression,
     override fun accept(visitor: AstWalker, parent: Node) = visitor.visit(this, parent)
 }
 
-class ForeverLoop(var body: AnonymousScope, override val position: Position) : Statement() {
+class RepeatLoop(var iterations: Expression?, var body: AnonymousScope, override val position: Position) : Statement() {
     override lateinit var parent: Node
-    override val expensiveToInline = true
 
     override fun linkParents(parent: Node) {
         this.parent = parent
+        iterations?.linkParents(this)
         body.linkParents(this)
     }
 
     override fun replaceChildNode(node: Node, replacement: Node) {
-        require(replacement is AnonymousScope && node===body)
-        body = replacement
+        when {
+            node===iterations -> iterations = replacement as Expression
+            node===body -> body = replacement as AnonymousScope
+            else -> throw FatalAstException("invalid replace")
+        }
         replacement.parent = this
     }
 
@@ -858,11 +813,10 @@ class ForeverLoop(var body: AnonymousScope, override val position: Position) : S
     override fun accept(visitor: AstWalker, parent: Node) = visitor.visit(this, parent)
 }
 
-class RepeatLoop(var body: AnonymousScope,
-                 var untilCondition: Expression,
-                 override val position: Position) : Statement() {
+class UntilLoop(var body: AnonymousScope,
+                var untilCondition: Expression,
+                override val position: Position) : Statement() {
     override lateinit var parent: Node
-    override val expensiveToInline = true
 
     override fun linkParents(parent: Node) {
         this.parent = parent
@@ -887,7 +841,6 @@ class WhenStatement(var condition: Expression,
                     var choices: MutableList<WhenChoice>,
                     override val position: Position): Statement() {
     override lateinit var parent: Node
-    override val expensiveToInline: Boolean = true
 
     override fun linkParents(parent: Node) {
         this.parent = parent
@@ -899,7 +852,7 @@ class WhenStatement(var condition: Expression,
         if(node===condition)
             condition = replacement as Expression
         else {
-            val idx = choices.indexOf(node)
+            val idx = choices.withIndex().find { it.value===node }!!.index
             choices[idx] = replacement as WhenChoice
         }
         replacement.parent = this
@@ -957,7 +910,6 @@ class StructDecl(override val name: String,
                  override val position: Position): Statement(), INameScope {
 
     override lateinit var parent: Node
-    override val expensiveToInline: Boolean = true
 
     override fun linkParents(parent: Node) {
         this.parent = parent
@@ -966,7 +918,7 @@ class StructDecl(override val name: String,
 
     override fun replaceChildNode(node: Node, replacement: Node) {
         require(replacement is Statement)
-        val idx = statements.indexOf(node)
+        val idx = statements.indexOfFirst { it===node }
         statements[idx] = replacement
         replacement.parent = this
     }

compiler/src/prog8/compiler/BeforeAsmGenerationAstChanger.kt

@@ -39,8 +39,8 @@ internal class BeforeAsmGenerationAstChanger(val program: Program, val errors: E
                 return 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(null, IdentifierReference(listOf(it.name), it.position), null, null, it.position)
-                    val assign = Assignment(target, null, initValue, it.position)
+                    val target = AssignTarget(IdentifierReference(listOf(it.name), it.position), null, null, it.position)
+                    val assign = Assignment(target, initValue, it.position)
                     initValue.parent = assign
                     IAstModification.InsertFirst(assign, scope)
                 } +  decls.map { IAstModification.ReplaceNode(it, NopStatement(it.position), scope) } +
@@ -89,7 +89,14 @@ internal class BeforeAsmGenerationAstChanger(val program: Program, val errors: E
                 return listOf(IAstModification.ReplaceNode(typecast, typecast.expression, parent))
             }
         }
-        else if(sourceDt in PassByReferenceDatatypes) {
+
+
+        // Note: for various reasons (most importantly, code simplicity), the code generator assumes/requires
+        // that the types of assignment values and their target are the same,
+        // and that the types of both operands of a binaryexpression node are the same.
+        // So, it is not easily possible to remove the typecasts that are there to make these conditions true.
+
+        if(sourceDt in PassByReferenceDatatypes) {
             if(typecast.type==DataType.UWORD) {
                 return listOf(IAstModification.ReplaceNode(
                         typecast,

compiler/src/prog8/compiler/Main.kt

@@ -42,7 +42,7 @@ fun compileProgram(filepath: Path,
                 optimizeAst(programAst, errors)
             postprocessAst(programAst, errors, compilationOptions)
 
-            // printAst(programAst) // TODO
+            // printAst(programAst)
 
             if(writeAssembly)
                 programName = writeAssembly(programAst, errors, outputDir, optimize, compilationOptions)
@@ -79,7 +79,7 @@ fun compileProgram(filepath: Path,
 
 private fun parseImports(filepath: Path, errors: ErrorReporter): Triple<Program, CompilationOptions, List<Path>> {
     println("Parsing...")
-    val importer = ModuleImporter(errors)
+    val importer = ModuleImporter()
     val programAst = Program(moduleName(filepath.fileName), mutableListOf())
     importer.importModule(programAst, filepath)
     errors.handle()
@@ -146,10 +146,10 @@ private fun processAst(programAst: Program, errors: ErrorReporter, compilerOptio
     errors.handle()
     programAst.constantFold(errors)
     errors.handle()
-    programAst.removeNopsFlattenAnonScopes()
     programAst.reorderStatements()
     programAst.addTypecasts(errors)
     errors.handle()
+    programAst.variousCleanups()
     programAst.checkValid(compilerOptions, errors)
     errors.handle()
     programAst.checkIdentifiers(errors)
@@ -169,21 +169,21 @@ private fun optimizeAst(programAst: Program, errors: ErrorReporter) {
             break
     }
 
-    val remover = UnusedCodeRemover()
+    val remover = UnusedCodeRemover(errors)
     remover.visit(programAst)
     remover.applyModifications()
+    errors.handle()
 }
 
 private fun postprocessAst(programAst: Program, errors: ErrorReporter, compilerOptions: CompilationOptions) {
-    programAst.transformAssignments(errors)
-    errors.handle()
     programAst.addTypecasts(errors)
     errors.handle()
-    programAst.removeNopsFlattenAnonScopes()
+    programAst.variousCleanups()
     programAst.checkValid(compilerOptions, errors)          // check if final tree is still valid
     errors.handle()
     programAst.checkRecursion(errors)         // check if there are recursive subroutine calls
     errors.handle()
+    programAst.verifyFunctionArgTypes()
 }
 
 private fun writeAssembly(programAst: Program, errors: ErrorReporter, outputDir: Path,

compiler/src/prog8/compiler/Zeropage.kt

@@ -16,7 +16,7 @@ abstract class Zeropage(protected val options: CompilationOptions) {
     fun available() = if(options.zeropage==ZeropageType.DONTUSE) 0 else free.size
 
     fun allocate(scopedname: String, datatype: DataType, position: Position?, errors: ErrorReporter): Int {
-        assert(scopedname.isEmpty() || !allocations.values.any { it.first==scopedname } ) {"isSameAs scopedname can't be allocated twice"}
+        assert(scopedname.isEmpty() || !allocations.values.any { it.first==scopedname } ) {"scopedname can't be allocated twice"}
 
         if(options.zeropage==ZeropageType.DONTUSE)
             throw CompilerException("zero page usage has been disabled")
@@ -39,13 +39,13 @@ abstract class Zeropage(protected val options: CompilationOptions) {
 
         if(free.size > 0) {
             if(size==1) {
-                for(candidate in free.min()!! .. free.max()!!+1) {
+                for(candidate in free.minOrNull()!! .. free.maxOrNull()!!+1) {
                     if(loneByte(candidate))
                         return makeAllocation(candidate, 1, datatype, scopedname)
                 }
                 return makeAllocation(free[0], 1, datatype, scopedname)
             }
-            for(candidate in free.min()!! .. free.max()!!+1) {
+            for(candidate in free.minOrNull()!! .. free.maxOrNull()!!+1) {
                 if (sequentialFree(candidate, size))
                     return makeAllocation(candidate, size, datatype, scopedname)
             }

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

@@ -8,6 +8,7 @@ interface IMachineDefinition {
     val FLOAT_MAX_NEGATIVE: Double
     val FLOAT_MAX_POSITIVE: Double
     val FLOAT_MEM_SIZE: Int
+    val POINTER_MEM_SIZE: Int
 
     val opcodeNames: Set<String>
 

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

@@ -14,9 +14,9 @@ class AssemblyProgram(override val name: String, outputDir: Path) : IAssemblyPro
     private val viceMonListFile = outputDir.resolve("$name.vice-mon-list")
 
     override fun assemble(options: CompilationOptions) {
-        // add "-Wlong-branch"  to see warnings about conversion of branch instructions to jumps
+        // 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", "-Wno-error=long-branch",
+                "-Wall", "-Wno-strict-bool", "-Wno-shadow", // "-Werror",
                 "--dump-labels", "--vice-labels", "-l", viceMonListFile.toString(), "--no-monitor")
 
         val outFile = when (options.output) {

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

@@ -5,9 +5,6 @@ import prog8.compiler.CompilerException
 import prog8.compiler.Zeropage
 import prog8.compiler.ZeropageType
 import prog8.compiler.target.IMachineDefinition
-import java.awt.Color
-import java.awt.image.BufferedImage
-import javax.imageio.ImageIO
 import kotlin.math.absoluteValue
 import kotlin.math.pow
 
@@ -17,6 +14,7 @@ object C64MachineDefinition: IMachineDefinition {
     override val FLOAT_MAX_POSITIVE = 1.7014118345e+38         // bytes: 255,127,255,255,255
     override val FLOAT_MAX_NEGATIVE = -1.7014118345e+38        // bytes: 255,255,255,255,255
     override val FLOAT_MEM_SIZE = 5
+    override val POINTER_MEM_SIZE = 2
     const val BASIC_LOAD_ADDRESS = 0x0801
     const val RAW_LOAD_ADDRESS = 0xc000
 
@@ -177,90 +175,4 @@ object C64MachineDefinition: IMachineDefinition {
             return if (sign) -result else result
         }
     }
-
-    object Charset {
-        private val normalImg = ImageIO.read(javaClass.getResource("/charset/c64/charset-normal.png"))
-        private val shiftedImg = ImageIO.read(javaClass.getResource("/charset/c64/charset-shifted.png"))
-
-        private fun scanChars(img: BufferedImage): Array<BufferedImage> {
-
-            val transparent = BufferedImage(img.width, img.height, BufferedImage.TYPE_INT_ARGB)
-            transparent.createGraphics().drawImage(img, 0, 0, null)
-
-            val black = Color(0, 0, 0).rgb
-            val nopixel = Color(0, 0, 0, 0).rgb
-            for (y in 0 until transparent.height) {
-                for (x in 0 until transparent.width) {
-                    val col = transparent.getRGB(x, y)
-                    if (col == black)
-                        transparent.setRGB(x, y, nopixel)
-                }
-            }
-
-            val numColumns = transparent.width / 8
-            val charImages = (0..255).map {
-                val charX = it % numColumns
-                val charY = it / numColumns
-                transparent.getSubimage(charX * 8, charY * 8, 8, 8)
-            }
-            return charImages.toTypedArray()
-        }
-
-        val normalChars = scanChars(normalImg)
-        val shiftedChars = scanChars(shiftedImg)
-
-        private val coloredNormalChars = mutableMapOf<Short, Array<BufferedImage>>()
-
-        fun getColoredChar(screenCode: Short, color: Short): BufferedImage {
-            val colorIdx = (color % colorPalette.size).toShort()
-            val chars = coloredNormalChars[colorIdx]
-            if (chars != null)
-                return chars[screenCode.toInt()]
-
-            val coloredChars = mutableListOf<BufferedImage>()
-            val transparent = Color(0, 0, 0, 0).rgb
-            val rgb = colorPalette[colorIdx.toInt()].rgb
-            for (c in normalChars) {
-                val colored = c.copy()
-                for (y in 0 until colored.height)
-                    for (x in 0 until colored.width) {
-                        if (colored.getRGB(x, y) != transparent) {
-                            colored.setRGB(x, y, rgb)
-                        }
-                    }
-                coloredChars.add(colored)
-            }
-            coloredNormalChars[colorIdx] = coloredChars.toTypedArray()
-            return coloredNormalChars.getValue(colorIdx)[screenCode.toInt()]
-        }
-
-    }
-
-    private fun BufferedImage.copy(): BufferedImage {
-        val bcopy = BufferedImage(this.width, this.height, this.type)
-        val g = bcopy.graphics
-        g.drawImage(this, 0, 0, null)
-        g.dispose()
-        return bcopy
-    }
-
-    val colorPalette = listOf(         // this is Pepto's Commodore-64 palette  http://www.pepto.de/projects/colorvic/
-            Color(0x000000),  // 0 = black
-            Color(0xFFFFFF),  // 1 = white
-            Color(0x813338),  // 2 = red
-            Color(0x75cec8),  // 3 = cyan
-            Color(0x8e3c97),  // 4 = purple
-            Color(0x56ac4d),  // 5 = green
-            Color(0x2e2c9b),  // 6 = blue
-            Color(0xedf171),  // 7 = yellow
-            Color(0x8e5029),  // 8 = orange
-            Color(0x553800),  // 9 = brown
-            Color(0xc46c71),  // 10 = light red
-            Color(0x4a4a4a),  // 11 = dark grey
-            Color(0x7b7b7b),  // 12 = medium grey
-            Color(0xa9ff9f),  // 13 = light green
-            Color(0x706deb),  // 14 = light blue
-            Color(0xb2b2b2)   // 15 = light grey
-    )
-
 }

compiler/src/prog8/compiler/target/c64/codegen/AsmGen.kt

@@ -1,5 +1,6 @@
 package prog8.compiler.target.c64.codegen
 
+import prog8.ast.INameScope
 import prog8.ast.Node
 import prog8.ast.Program
 import prog8.ast.antlr.escape
@@ -26,9 +27,9 @@ import kotlin.math.absoluteValue
 
 
 internal class AsmGen(private val program: Program,
-                      private val errors: ErrorReporter,
-                      private val zeropage: Zeropage,
-                      private val options: CompilationOptions,
+                      val errors: ErrorReporter,
+                      val zeropage: Zeropage,
+                      val options: CompilationOptions,
                       private val outputDir: Path): IAssemblyGenerator {
 
     private val assemblyLines = mutableListOf<String>()
@@ -39,16 +40,14 @@ internal class AsmGen(private val program: Program,
     private val forloopsAsmGen = ForLoopsAsmGen(program, this)
     private val postincrdecrAsmGen = PostIncrDecrAsmGen(program, this)
     private val functioncallAsmGen = FunctionCallAsmGen(program, this)
-    private val assignmentAsmGen = AssignmentAsmGen(program, errors, this)
+    private val assignmentAsmGen = AssignmentAsmGen(program, this)
     private val expressionsAsmGen = ExpressionsAsmGen(program, this)
     internal val loopEndLabels = ArrayDeque<String>()
-    internal val loopContinueLabels = ArrayDeque<String>()
     internal val blockLevelVarInits = mutableMapOf<Block, MutableSet<VarDecl>>()
 
     override fun compileToAssembly(optimize: Boolean): IAssemblyProgram {
         assemblyLines.clear()
         loopEndLabels.clear()
-        loopContinueLabels.clear()
 
         println("Generating assembly code... ")
 
@@ -183,8 +182,8 @@ internal class AsmGen(private val program: Program,
             blockLevelVarInits.getValue(block).forEach { decl ->
                 val scopedFullName = decl.makeScopedName(decl.name).split('.')
                 require(scopedFullName.first()==block.name)
-                val target = AssignTarget(null, IdentifierReference(scopedFullName.drop(1), decl.position), null, null, decl.position)
-                val assign = Assignment(target, null, decl.value!!, decl.position)
+                val target = AssignTarget(IdentifierReference(scopedFullName.drop(1), decl.position), null, null, decl.position)
+                val assign = Assignment(target, decl.value!!, decl.position)
                 assign.linkParents(decl.parent)
                 assignmentAsmGen.translate(assign)
             }
@@ -561,19 +560,19 @@ internal class AsmGen(private val program: Program,
         }
     }
 
-    internal fun saveRegister(register: Register) {
+    internal fun saveRegister(register: CpuRegister) {
         when(register) {
-            Register.A -> out("  pha")
-            Register.X -> out("  txa | pha")
-            Register.Y -> out("  tya | pha")
+            CpuRegister.A -> out("  pha")
+            CpuRegister.X -> out("  txa | pha")
+            CpuRegister.Y -> out("  tya | pha")
         }
     }
 
-    internal fun restoreRegister(register: Register) {
+    internal fun restoreRegister(register: CpuRegister) {
         when(register) {
-            Register.A -> out("  pla")
-            Register.X -> out("  pla | tax")
-            Register.Y -> out("  pla | tay")
+            CpuRegister.A -> out("  pla")
+            CpuRegister.X -> out("  pla | tax")
+            CpuRegister.Y -> out("  pla | tay")
         }
     }
 
@@ -637,11 +636,14 @@ internal class AsmGen(private val program: Program,
             is BranchStatement -> translate(stmt)
             is IfStatement -> translate(stmt)
             is ForLoop -> forloopsAsmGen.translate(stmt)
-            is Continue -> out("  jmp  ${loopContinueLabels.peek()}")
-            is Break -> out("  jmp  ${loopEndLabels.peek()}")
+            is Break -> {
+                if(loopEndLabels.isEmpty())
+                    throw AssemblyError("break statement out of context  ${stmt.position}")
+                out("  jmp  ${loopEndLabels.peek()}")
+            }
             is WhileLoop -> translate(stmt)
-            is ForeverLoop -> translate(stmt)
             is RepeatLoop -> translate(stmt)
+            is UntilLoop -> translate(stmt)
             is WhenStatement -> translate(stmt)
             is BuiltinFunctionStatementPlaceholder -> throw AssemblyError("builtin function should not have placeholder anymore?")
             is AnonymousScope -> translate(stmt)
@@ -672,26 +674,126 @@ internal class AsmGen(private val program: Program,
         }
     }
 
-    private fun translate(stmt: ForeverLoop) {
-        val foreverLabel = makeLabel("forever")
-        val endLabel = makeLabel("foreverend")
+    private fun translate(stmt: RepeatLoop) {
+        val repeatLabel = makeLabel("repeat")
+        val endLabel = makeLabel("repeatend")
         loopEndLabels.push(endLabel)
-        loopContinueLabels.push(foreverLabel)
-        out(foreverLabel)
-        translate(stmt.body)
-        out("  jmp  $foreverLabel")
-        out(endLabel)
+
+        when (stmt.iterations) {
+            null -> {
+                // endless loop
+                out(repeatLabel)
+                translate(stmt.body)
+                out("  jmp  $repeatLabel")
+                out(endLabel)
+            }
+            is NumericLiteralValue -> {
+                val iterations = (stmt.iterations as NumericLiteralValue).number.toInt()
+                if(iterations<0 || iterations > 65536)
+                    throw AssemblyError("invalid number of iterations")
+                when {
+                    iterations == 0 -> {}
+                    iterations <= 256 -> {
+                        out("  lda  #${iterations and 255}")
+                        repeatByteCountInA(iterations, repeatLabel, endLabel, stmt.body)
+                    }
+                    else -> {
+                        out("  lda  #<${iterations} |  ldy  #>${iterations}")
+                        repeatWordCountInAY(iterations, repeatLabel, endLabel, stmt.body)
+                    }
+                }
+            }
+            is IdentifierReference -> {
+                val vardecl = (stmt.iterations as IdentifierReference).targetStatement(program.namespace) as VarDecl
+                val name = asmIdentifierName(stmt.iterations as IdentifierReference)
+                when(vardecl.datatype) {
+                    DataType.UBYTE, DataType.BYTE -> {
+                        out("  lda  $name")
+                        repeatByteCountInA(null, repeatLabel, endLabel, stmt.body)
+                    }
+                    DataType.UWORD, DataType.WORD -> {
+                        out("  lda  $name |  ldy  $name+1")
+                        repeatWordCountInAY(null, repeatLabel, endLabel, stmt.body)
+                    }
+                    else -> throw AssemblyError("invalid loop variable datatype $vardecl")
+                }
+            }
+            else -> {
+                translateExpression(stmt.iterations!!)
+                val dt = stmt.iterations!!.inferType(program).typeOrElse(DataType.STRUCT)
+                when (dt) {
+                    in ByteDatatypes -> {
+                        out("  inx |  lda  ${ESTACK_LO_HEX},x")
+                        repeatByteCountInA(null, repeatLabel, endLabel, stmt.body)
+                    }
+                    in WordDatatypes -> {
+                        out("  inx |  lda  ${ESTACK_LO_HEX},x |  ldy  ${ESTACK_HI_HEX},x")
+                        repeatWordCountInAY(null, repeatLabel, endLabel, stmt.body)
+                    }
+                    else -> throw AssemblyError("invalid loop expression datatype $dt")
+                }
+            }
+        }
+
         loopEndLabels.pop()
-        loopContinueLabels.pop()
+    }
+
+    private fun repeatWordCountInAY(constIterations: Int?, repeatLabel: String, endLabel: String, body: AnonymousScope) {
+        // note: A/Y must have been loaded with the number of iterations already!
+        val counterVar = makeLabel("repeatcounter")
+        out("""
+                sta  $counterVar
+                sty  $counterVar+1
+$repeatLabel    lda  $counterVar
+                bne  +
+                lda  $counterVar+1
+                beq  $endLabel
++               lda  $counterVar
+                bne  +
+                dec  $counterVar+1
++               dec  $counterVar
+""")
+        translate(body)
+        out("  jmp  $repeatLabel")
+        if(constIterations!=null && constIterations>=16 && zeropage.available() > 1) {
+            // allocate count var on ZP
+            val zpAddr = zeropage.allocate(counterVar, DataType.UWORD, body.position, errors)
+            out("""$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 already!
+        val counterVar = makeLabel("repeatcounter")
+        out("""
+            sta  $counterVar
+$repeatLabel""")
+        translate(body)
+        out("""
+             dec  $counterVar
+             bne  $repeatLabel
+             beq  $endLabel""")
+        if(constIterations!=null && constIterations>=16 && zeropage.available() > 0) {
+            // allocate count var on ZP
+            val zpAddr = zeropage.allocate(counterVar, DataType.UBYTE, body.position, errors)
+            out("""$counterVar = $zpAddr  ; auto zp UBYTE""")
+        } else {
+            out("""
+$counterVar    .byte  0""")
+        }
+        out(endLabel)
     }
 
     private fun translate(stmt: WhileLoop) {
         val whileLabel = makeLabel("while")
         val endLabel = makeLabel("whileend")
         loopEndLabels.push(endLabel)
-        loopContinueLabels.push(whileLabel)
         out(whileLabel)
-        // TODO optimize for the simple cases, can we avoid stack use?
         expressionsAsmGen.translateExpression(stmt.condition)
         val conditionDt = stmt.condition.inferType(program)
         if(!conditionDt.isKnown)
@@ -711,16 +813,13 @@ internal class AsmGen(private val program: Program,
         out("  jmp  $whileLabel")
         out(endLabel)
         loopEndLabels.pop()
-        loopContinueLabels.pop()
     }
 
-    private fun translate(stmt: RepeatLoop) {
+    private fun translate(stmt: UntilLoop) {
         val repeatLabel = makeLabel("repeat")
         val endLabel = makeLabel("repeatend")
         loopEndLabels.push(endLabel)
-        loopContinueLabels.push(repeatLabel)
         out(repeatLabel)
-        // TODO optimize this for the simple cases, can we avoid stack use?
         translate(stmt.body)
         expressionsAsmGen.translateExpression(stmt.untilCondition)
         val conditionDt = stmt.untilCondition.inferType(program)
@@ -739,7 +838,6 @@ internal class AsmGen(private val program: Program,
         }
         out(endLabel)
         loopEndLabels.pop()
-        loopContinueLabels.pop()
     }
 
     private fun translate(stmt: WhenStatement) {
@@ -771,7 +869,7 @@ internal class AsmGen(private val program: Program,
                             bne  +
                             cpy  #>${value.toHex()}
                             beq  $choiceLabel
-+                            
++
                             """)
                     }
                 }
@@ -838,10 +936,13 @@ internal class AsmGen(private val program: Program,
                 }
                 inits.add(stmt)
             } else {
-                val target = AssignTarget(null, IdentifierReference(listOf(stmt.name), stmt.position), null, null, stmt.position)
-                val assign = Assignment(target, null, stmt.value!!, stmt.position)
-                assign.linkParents(stmt.parent)
-                translate(assign)
+                val next = (stmt.parent as INameScope).nextSibling(stmt)
+                if (next !is ForLoop || next.loopVar.nameInSource.single() != stmt.name) {
+                    val target = AssignTarget(IdentifierReference(listOf(stmt.name), stmt.position), null, null, stmt.position)
+                    val assign = Assignment(target, stmt.value!!, stmt.position)
+                    assign.linkParents(stmt.parent)
+                    translate(assign)
+                }
             }
         }
     }
@@ -903,18 +1004,10 @@ internal class AsmGen(private val program: Program,
     internal fun translateArrayIndexIntoA(expr: ArrayIndexedExpression) {
         when (val index = expr.arrayspec.index) {
             is NumericLiteralValue -> throw AssemblyError("this should be optimized directly")
-            is RegisterExpr -> {
-                when (index.register) {
-                    Register.A -> {}
-                    Register.X -> out("  txa")
-                    Register.Y -> out("  tya")
-                }
-            }
             is IdentifierReference -> {
                 val indexName = asmIdentifierName(index)
                 out("  lda  $indexName")
             }
-            // TODO optimize more cases
             else -> {
                 expressionsAsmGen.translateExpression(index)
                 out("  inx |  lda  $ESTACK_LO_HEX,x")
@@ -922,28 +1015,6 @@ internal class AsmGen(private val program: Program,
         }
     }
 
-    internal fun translateArrayIndexIntoY(expr: ArrayIndexedExpression) {
-        when (val index = expr.arrayspec.index) {
-            is NumericLiteralValue -> throw AssemblyError("this should be optimized directly")
-            is RegisterExpr -> {
-                when (index.register) {
-                    Register.A -> out("  tay")
-                    Register.X -> out("  txa |  tay")
-                    Register.Y -> {}
-                }
-            }
-            is IdentifierReference -> {
-                val indexName = asmIdentifierName(index)
-                out("  ldy  $indexName")
-            }
-            // TODO optimize more cases, see translateArrayIndexIntoA
-            else -> {
-                expressionsAsmGen.translateExpression(index)
-                out("  inx |  ldy  $ESTACK_LO_HEX,x")
-            }
-        }
-    }
-
     internal fun translateExpression(expression: Expression) =
             expressionsAsmGen.translateExpression(expression)
 
@@ -953,30 +1024,6 @@ internal class AsmGen(private val program: Program,
     internal fun translateFunctionCall(functionCall: FunctionCall) =
             functioncallAsmGen.translateFunctionCall(functionCall)
 
-    internal fun assignFromEvalResult(target: AssignTarget) =
-            assignmentAsmGen.assignFromEvalResult(target)
-
-    fun assignFromByteConstant(target: AssignTarget, value: Short) =
-            assignmentAsmGen.assignFromByteConstant(target, value)
-
-    fun assignFromWordConstant(target: AssignTarget, value: Int) =
-            assignmentAsmGen.assignFromWordConstant(target, value)
-
-    fun assignFromFloatConstant(target: AssignTarget, value: Double) =
-            assignmentAsmGen.assignFromFloatConstant(target, value)
-
-    fun assignFromByteVariable(target: AssignTarget, variable: IdentifierReference) =
-            assignmentAsmGen.assignFromByteVariable(target, variable)
-
-    fun assignFromWordVariable(target: AssignTarget, variable: IdentifierReference) =
-            assignmentAsmGen.assignFromWordVariable(target, variable)
-
-    fun assignFromFloatVariable(target: AssignTarget, variable: IdentifierReference) =
-            assignmentAsmGen.assignFromFloatVariable(target, variable)
-
-    fun assignFromRegister(target: AssignTarget, register: Register) =
-            assignmentAsmGen.assignFromRegister(target, register)
-
-    fun assignFromMemoryByte(target: AssignTarget, address: Int?, identifier: IdentifierReference?) =
-            assignmentAsmGen.assignFromMemoryByte(target, address, identifier)
+    internal fun assignToRegister(reg: CpuRegister, value: Short?, identifier: IdentifierReference?) =
+            assignmentAsmGen.assignToRegister(reg, value, identifier)
 }

compiler/src/prog8/compiler/target/c64/codegen/BuiltinFunctionsAsmGen.kt

@@ -2,12 +2,8 @@ package prog8.compiler.target.c64.codegen
 
 import prog8.ast.IFunctionCall
 import prog8.ast.Program
-import prog8.ast.base.ByteDatatypes
-import prog8.ast.base.DataType
-import prog8.ast.base.Register
-import prog8.ast.base.WordDatatypes
+import prog8.ast.base.*
 import prog8.ast.expressions.*
-import prog8.ast.statements.AssignTarget
 import prog8.ast.statements.FunctionCallStatement
 import prog8.compiler.AssemblyError
 import prog8.compiler.target.c64.C64MachineDefinition.C64Zeropage
@@ -39,6 +35,7 @@ internal class BuiltinFunctionsAsmGen(private val program: Program, private val
 
         when (functionName) {
             "msb" -> funcMsb(fcall)
+            "lsb" -> funcLsb(fcall)
             "mkword" -> funcMkword(fcall, func)
             "abs" -> funcAbs(fcall, func)
             "swap" -> funcSwap(fcall)
@@ -176,13 +173,6 @@ internal class BuiltinFunctionsAsmGen(private val program: Program, private val
                             asmgen.out("  jsr  prog8_lib.ror2_mem_ub")
                         }
                     }
-                    is RegisterExpr -> {
-                        when (what.register) {
-                            Register.A -> asmgen.out("  lsr  a |  bcc  + |  ora  #\$80 |+  ")
-                            Register.X -> asmgen.out("  txa |  lsr  a |  bcc  + |  ora  #\$80 |+  tax ")
-                            Register.Y -> asmgen.out("  tya |  lsr  a |  bcc  + |  ora  #\$80 |+  tay ")
-                        }
-                    }
                     is IdentifierReference -> {
                         val variable = asmgen.asmIdentifierName(what)
                         asmgen.out("  lda  $variable |  lsr  a |  bcc  + |  ora  #\$80 |+  |  sta  $variable")
@@ -235,13 +225,6 @@ internal class BuiltinFunctionsAsmGen(private val program: Program, private val
                                         """)
                         }
                     }
-                    is RegisterExpr -> {
-                        when (what.register) {
-                            Register.A -> asmgen.out("  ror  a")
-                            Register.X -> asmgen.out("  txa |  ror  a |  tax")
-                            Register.Y -> asmgen.out("  tya |  ror  a |  tay")
-                        }
-                    }
                     is IdentifierReference -> {
                         val variable = asmgen.asmIdentifierName(what)
                         asmgen.out("  ror  $variable")
@@ -287,13 +270,6 @@ internal class BuiltinFunctionsAsmGen(private val program: Program, private val
                             asmgen.out("  jsr  prog8_lib.rol2_mem_ub")
                         }
                     }
-                    is RegisterExpr -> {
-                        when (what.register) {
-                            Register.A -> asmgen.out("  cmp  #\$80 |  rol  a  ")
-                            Register.X -> asmgen.out("  txa  |  cmp  #\$80 |  rol  a  |  tax")
-                            Register.Y -> asmgen.out("  tya  |  cmp  #\$80 |  rol  a  |  tay")
-                        }
-                    }
                     is IdentifierReference -> {
                         val variable = asmgen.asmIdentifierName(what)
                         asmgen.out("  lda  $variable |  cmp  #\$80 |  rol  a |  sta  $variable")
@@ -346,13 +322,6 @@ internal class BuiltinFunctionsAsmGen(private val program: Program, private val
                                         """)
                         }
                     }
-                    is RegisterExpr -> {
-                        when (what.register) {
-                            Register.A -> asmgen.out("  rol  a")
-                            Register.X -> asmgen.out("  txa |  rol  a |  tax")
-                            Register.Y -> asmgen.out("  tya |  rol  a |  tay")
-                        }
-                    }
                     is IdentifierReference -> {
                         val variable = asmgen.asmIdentifierName(what)
                         asmgen.out("  rol  $variable")
@@ -384,13 +353,6 @@ internal class BuiltinFunctionsAsmGen(private val program: Program, private val
         when (dt.typeOrElse(DataType.STRUCT)) {
             DataType.UBYTE -> {
                 when (what) {
-                    is RegisterExpr -> {
-                        when (what.register) {
-                            Register.A -> asmgen.out("  lsr  a")
-                            Register.X -> asmgen.out("  txa  |  lsr  a |  tax")
-                            Register.Y -> asmgen.out("  tya  |  lsr  a |  tay")
-                        }
-                    }
                     is IdentifierReference -> asmgen.out("  lsr  ${asmgen.asmIdentifierName(what)}")
                     is DirectMemoryRead -> {
                         if (what.addressExpression is NumericLiteralValue) {
@@ -468,13 +430,6 @@ internal class BuiltinFunctionsAsmGen(private val program: Program, private val
         when (dt.typeOrElse(DataType.STRUCT)) {
             in ByteDatatypes -> {
                 when (what) {
-                    is RegisterExpr -> {
-                        when (what.register) {
-                            Register.A -> asmgen.out("  asl  a")
-                            Register.X -> asmgen.out("  txa  |  asl  a |  tax")
-                            Register.Y -> asmgen.out("  tya  |  asl  a |  tay")
-                        }
-                    }
                     is IdentifierReference -> asmgen.out("  asl  ${asmgen.asmIdentifierName(what)}")
                     is DirectMemoryRead -> {
                         if (what.addressExpression is NumericLiteralValue) {
@@ -581,32 +536,32 @@ internal class BuiltinFunctionsAsmGen(private val program: Program, private val
                     ldy  $firstName
                     lda  $secondName
                     sta  $firstName
-                    tya
-                    sta  $secondName
+                    sty  $secondName
                     ldy  $firstName+1
                     lda  $secondName+1
                     sta  $firstName+1
-                    tya
-                    sta  $secondName+1
+                    sty  $secondName+1
                 """)
                 return
             }
             if(dt.istype(DataType.FLOAT)) {
-                TODO("optimized case for swapping 2 float vars-- asm subroutine")
+                asmgen.out("""
+                    lda  #<$firstName
+                    sta  ${C64Zeropage.SCRATCH_W1}
+                    lda  #>$firstName
+                    sta  ${C64Zeropage.SCRATCH_W1+1}
+                    lda  #<$secondName
+                    sta  ${C64Zeropage.SCRATCH_W2}
+                    lda  #>$secondName
+                    sta  ${C64Zeropage.SCRATCH_W2+1}
+                    jsr  c64flt.swap_floats
+                """)
                 return
             }
         }
 
-        // TODO more optimized cases? for instance swapping elements of array vars?
-
-        // suboptimal code via the evaluation stack...
-        asmgen.translateExpression(first)
-        asmgen.translateExpression(second)
-        // pop in reverse order
-        val firstTarget = AssignTarget.fromExpr(first)
-        val secondTarget = AssignTarget.fromExpr(second)
-        asmgen.assignFromEvalResult(firstTarget)
-        asmgen.assignFromEvalResult(secondTarget)
+        // other types of swap() calls should have been replaced by a different statement sequence involving a temp variable
+        throw AssemblyError("no asm generation for swap funccall $fcall")
     }
 
     private fun funcAbs(fcall: IFunctionCall, func: FSignature) {
@@ -630,7 +585,7 @@ internal class BuiltinFunctionsAsmGen(private val program: Program, private val
         if (arg.inferType(program).typeOrElse(DataType.STRUCT) !in WordDatatypes)
             throw AssemblyError("msb required word argument")
         if (arg is NumericLiteralValue)
-            throw AssemblyError("should have been const-folded")
+            throw AssemblyError("msb(const) should have been const-folded away")
         if (arg is IdentifierReference) {
             val sourceName = asmgen.asmIdentifierName(arg)
             asmgen.out("  lda  $sourceName+1 |  sta  $ESTACK_LO_HEX,x |  dex")
@@ -640,6 +595,21 @@ internal class BuiltinFunctionsAsmGen(private val program: Program, private val
         }
     }
 
+    private fun funcLsb(fcall: IFunctionCall) {
+        val arg = fcall.args.single()
+        if (arg.inferType(program).typeOrElse(DataType.STRUCT) !in WordDatatypes)
+            throw AssemblyError("lsb required word argument")
+        if (arg is NumericLiteralValue)
+            throw AssemblyError("lsb(const) should have been const-folded away")
+        if (arg is IdentifierReference) {
+            val sourceName = asmgen.asmIdentifierName(arg)
+            asmgen.out("  lda  $sourceName |  sta  $ESTACK_LO_HEX,x |  dex")
+        } else {
+            asmgen.translateExpression(arg)
+            // just ignore any high-byte
+        }
+    }
+
     private fun outputPushAddressAndLenghtOfArray(arg: Expression) {
         arg as IdentifierReference
         val identifierName = asmgen.asmIdentifierName(arg)

compiler/src/prog8/compiler/target/c64/codegen/ExpressionsAsmGen.kt

@@ -25,11 +25,9 @@ internal class ExpressionsAsmGen(private val program: Program, private val asmge
             is AddressOf -> translateExpression(expression)
             is DirectMemoryRead -> translateExpression(expression)
             is NumericLiteralValue -> translateExpression(expression)
-            is RegisterExpr -> translateExpression(expression)
             is IdentifierReference -> translateExpression(expression)
             is FunctionCall -> translateExpression(expression)
             is ArrayLiteralValue, is StringLiteralValue -> throw AssemblyError("no asm gen for string/array literal value assignment - should have been replaced by a variable")
-            is StructLiteralValue -> throw AssemblyError("struct literal value assignment should have been flattened")
             is RangeExpr -> throw AssemblyError("range expression should have been changed into array values")
         }
     }
@@ -142,16 +140,17 @@ internal class ExpressionsAsmGen(private val program: Program, private val asmge
                 val sourceName = asmgen.asmIdentifierName(expr.addressExpression as IdentifierReference)
                 asmgen.out("""
         lda  $sourceName
-        sta  (+) +1
+        sta  ${C64MachineDefinition.C64Zeropage.SCRATCH_W1}
         lda  $sourceName+1
-        sta  (+) +2
-+       lda  ${'$'}ffff     ; modified
+        sta  ${C64MachineDefinition.C64Zeropage.SCRATCH_W1+1}
+        ldy  #0
+        lda  (${C64MachineDefinition.C64Zeropage.SCRATCH_W1}),y
         sta  $ESTACK_LO_HEX,x
         dex""")
             }
             else -> {
                 translateExpression(expr.addressExpression)
-                asmgen.out("  jsr  prog8_lib.read_byte_from_address")
+                asmgen.out("  jsr  prog8_lib.read_byte_from_address_on_stack")
                 asmgen.out("  sta  $ESTACK_LO_PLUS1_HEX,x")
             }
         }
@@ -175,14 +174,6 @@ internal class ExpressionsAsmGen(private val program: Program, private val asmge
         }
     }
 
-    private fun translateExpression(expr: RegisterExpr) {
-        when(expr.register) {
-            Register.A -> asmgen.out(" sta  $ESTACK_LO_HEX,x | dex")
-            Register.X -> asmgen.out(" txa |  sta  $ESTACK_LO_HEX,x | dex")
-            Register.Y -> asmgen.out(" tya |  sta  $ESTACK_LO_HEX,x | dex")
-        }
-    }
-
     private fun translateExpression(expr: IdentifierReference) {
         val varname = asmgen.asmIdentifierName(expr)
         when(expr.inferType(program).typeOrElse(DataType.STRUCT)) {
@@ -204,7 +195,6 @@ internal class ExpressionsAsmGen(private val program: Program, private val asmge
 
     private val optimizedByteMultiplications = setOf(3,5,6,7,9,10,11,12,13,14,15,20,25,40)
     private val optimizedWordMultiplications = setOf(3,5,6,7,9,10,12,15,20,25,40)
-    private val powersOfTwo = setOf(0,1,2,4,8,16,32,64,128,256)
 
     private fun translateExpression(expr: BinaryExpression) {
         val leftIDt = expr.left.inferType(program)
@@ -240,16 +230,26 @@ internal class ExpressionsAsmGen(private val program: Program, private val asmge
                         }
                     }
                     DataType.UWORD -> {
-                        if(amount<=2)
-                            repeat(amount) { asmgen.out(" lsr  $ESTACK_HI_PLUS1_HEX,x |  ror  $ESTACK_LO_PLUS1_HEX,x") }
+                        var left = amount
+                        while(left>=7) {
+                            asmgen.out(" jsr  math.shift_right_uw_7")
+                            left -= 7
+                        }
+                        if (left in 0..2)
+                            repeat(left) { asmgen.out(" lsr  $ESTACK_HI_PLUS1_HEX,x |  ror  $ESTACK_LO_PLUS1_HEX,x") }
                         else
-                            asmgen.out(" jsr  math.shift_right_uw_$amount")    // 3-7 (8+ is done via other optimizations)
+                            asmgen.out(" jsr  math.shift_right_uw_$left")
                     }
                     DataType.WORD -> {
-                        if(amount<=2)
-                            repeat(amount) { asmgen.out(" lda  $ESTACK_HI_PLUS1_HEX,x |  asl a  |  ror  $ESTACK_HI_PLUS1_HEX,x |  ror  $ESTACK_LO_PLUS1_HEX,x") }
+                        var left = amount
+                        while(left>=7) {
+                            asmgen.out(" jsr  math.shift_right_w_7")
+                            left -= 7
+                        }
+                        if (left in 0..2)
+                            repeat(left) { asmgen.out(" lda  $ESTACK_HI_PLUS1_HEX,x |  asl a  |  ror  $ESTACK_HI_PLUS1_HEX,x |  ror  $ESTACK_LO_PLUS1_HEX,x") }
                         else
-                            asmgen.out(" jsr  math.shift_right_w_$amount")  // 3-7 (8+ is done via other optimizations)
+                            asmgen.out(" jsr  math.shift_right_w_$left")
                     }
                     else -> throw AssemblyError("weird type")
                 }
@@ -269,11 +269,15 @@ internal class ExpressionsAsmGen(private val program: Program, private val asmge
                     }
                 }
                 else {
-                    if(amount<=2) {
-                        repeat(amount) { asmgen.out("  asl  $ESTACK_LO_PLUS1_HEX,x |  rol  $ESTACK_HI_PLUS1_HEX,x") }
-                    } else {
-                        asmgen.out(" jsr  math.shift_left_w_$amount")      // 3-7 (8+ is done via other optimizations)
+                    var left=amount
+                    while(left>=7) {
+                        asmgen.out(" jsr  math.shift_left_w_7")
+                        left -= 7
                     }
+                    if (left in 0..2)
+                        repeat(left) { asmgen.out("  asl  $ESTACK_LO_PLUS1_HEX,x |  rol  $ESTACK_HI_PLUS1_HEX,x") }
+                    else
+                        asmgen.out(" jsr  math.shift_left_w_$left")
                 }
                 return
             }

compiler/src/prog8/compiler/target/c64/codegen/ForLoopsAsmGen.kt

@@ -2,7 +2,6 @@ package prog8.compiler.target.c64.codegen
 
 import prog8.ast.Program
 import prog8.ast.base.DataType
-import prog8.ast.base.Register
 import prog8.ast.expressions.IdentifierReference
 import prog8.ast.expressions.RangeExpr
 import prog8.ast.statements.AssignTarget
@@ -15,10 +14,6 @@ import prog8.compiler.target.c64.C64MachineDefinition.ESTACK_LO_PLUS1_HEX
 import prog8.compiler.toHex
 import kotlin.math.absoluteValue
 
-// todo choose more efficient comparisons to avoid needless lda's
-// todo optimize common case step == 2 / -2
-
-
 internal class ForLoopsAsmGen(private val program: Program, private val asmgen: AsmGen) {
 
     internal fun translate(stmt: ForLoop) {
@@ -44,9 +39,9 @@ internal class ForLoopsAsmGen(private val program: Program, private val asmgen:
     private fun translateForOverNonconstRange(stmt: ForLoop, iterableDt: DataType, range: RangeExpr) {
         val loopLabel = asmgen.makeLabel("for_loop")
         val endLabel = asmgen.makeLabel("for_end")
-        val continueLabel = asmgen.makeLabel("for_continue")
+        val modifiedLabel = asmgen.makeLabel("for_modified")
+        val modifiedLabel2 = asmgen.makeLabel("for_modifiedb")
         asmgen.loopEndLabels.push(endLabel)
-        asmgen.loopContinueLabels.push(continueLabel)
         val stepsize=range.step.constValue(program)!!.number.toInt()
         when(iterableDt) {
             DataType.ARRAY_B, DataType.ARRAY_UB -> {
@@ -55,113 +50,62 @@ internal class ForLoopsAsmGen(private val program: Program, private val asmgen:
                     // bytes, step 1 or -1
 
                     val incdec = if(stepsize==1) "inc" else "dec"
-                    if (stmt.loopRegister != null) {
-                        // loop register over range
-                        if(stmt.loopRegister!= Register.A)
-                            throw AssemblyError("can only use A")
-                        asmgen.translateExpression(range.to)
-                        asmgen.translateExpression(range.from)
-                        asmgen.out("""
+                    // loop over byte range via loopvar
+                    val varname = asmgen.asmIdentifierName(stmt.loopVar)
+                    asmgen.translateExpression(range.to)
+                    asmgen.translateExpression(range.from)
+                    asmgen.out("""
                 inx
-                lda  ${ESTACK_LO_HEX},x
-                sta  $loopLabel+1
-$loopLabel      lda  #0                 ; modified""")
-                        asmgen.translate(stmt.body)
-                        asmgen.out("""
-$continueLabel  lda  $loopLabel+1
-                cmp  $ESTACK_LO_PLUS1_HEX,x
-                beq  $endLabel
-                $incdec  $loopLabel+1
-                jmp  $loopLabel
-$endLabel       inx""")
-                    } else {
-                        // loop over byte range via loopvar
-                        val varname = asmgen.asmIdentifierName(stmt.loopVar!!)
-                        asmgen.translateExpression(range.to)
-                        asmgen.translateExpression(range.from)
-                        asmgen.out("""
-                inx
-                lda  ${ESTACK_LO_HEX},x
+                lda  $ESTACK_LO_HEX,x
                 sta  $varname
+                lda  $ESTACK_LO_PLUS1_HEX,x
+                sta  $modifiedLabel+1
 $loopLabel""")
                         asmgen.translate(stmt.body)
                         asmgen.out("""
-$continueLabel  lda  $varname
-                cmp  $ESTACK_LO_PLUS1_HEX,x
+                lda  $varname
+$modifiedLabel  cmp  #0         ; modified 
                 beq  $endLabel
                 $incdec  $varname
                 jmp  $loopLabel
 $endLabel       inx""")
-                    }
-                }
-                else {
+
+                } else {
 
                     // bytes, step >= 2 or <= -2
 
-                    if (stmt.loopRegister != null) {
-                        // loop register over range
-                        if(stmt.loopRegister!= Register.A)
-                            throw AssemblyError("can only use A")
-                        asmgen.translateExpression(range.to)
-                        asmgen.translateExpression(range.from)
-                        asmgen.out("""
+                    // loop over byte range via loopvar
+                    val varname = asmgen.asmIdentifierName(stmt.loopVar)
+                    asmgen.translateExpression(range.to)
+                    asmgen.translateExpression(range.from)
+                    asmgen.out("""
                 inx
-                lda  ${ESTACK_LO_HEX},x
-                sta  $loopLabel+1
-$loopLabel      lda  #0                 ; modified""")
-                        asmgen.translate(stmt.body)
-                        asmgen.out("""
-$continueLabel  lda  $loopLabel+1""")
-                        if(stepsize>0) {
-                            asmgen.out("""
-                clc
-                adc  #$stepsize
-                sta  $loopLabel+1
-                cmp  $ESTACK_LO_PLUS1_HEX,x
-                bcc  $loopLabel
-                beq  $loopLabel""")
-                        } else {
-                            asmgen.out("""
-                sec
-                sbc  #${stepsize.absoluteValue}
-                sta  $loopLabel+1
-                cmp  $ESTACK_LO_PLUS1_HEX,x
-                bcs  $loopLabel""")
-                        }
-                        asmgen.out("""
-$endLabel       inx""")
-                    } else {
-                        // loop over byte range via loopvar
-                        val varname = asmgen.asmIdentifierName(stmt.loopVar!!)
-                        asmgen.translateExpression(range.to)
-                        asmgen.translateExpression(range.from)
-                        asmgen.out("""
-                inx
-                lda  ${ESTACK_LO_HEX},x
+                lda  $ESTACK_LO_HEX,x
                 sta  $varname
+                lda  $ESTACK_LO_PLUS1_HEX,x
+                sta  $modifiedLabel+1
 $loopLabel""")
-                        asmgen.translate(stmt.body)
+                    asmgen.translate(stmt.body)
+                    asmgen.out("""
+                lda  $varname""")
+                    if(stepsize>0) {
                         asmgen.out("""
-$continueLabel  lda  $varname""")
-                        if(stepsize>0) {
-                            asmgen.out("""
                 clc
                 adc  #$stepsize
                 sta  $varname
-                cmp  $ESTACK_LO_PLUS1_HEX,x
+$modifiedLabel  cmp  #0    ; modified
                 bcc  $loopLabel
                 beq  $loopLabel""")
-                        } else {
-                            asmgen.out("""
+                    } else {
+                        asmgen.out("""
                 sec
                 sbc  #${stepsize.absoluteValue}
                 sta  $varname
-                cmp  $ESTACK_LO_PLUS1_HEX,x
+$modifiedLabel  cmp  #0     ; modified 
                 bcs  $loopLabel""")
-                        }
-                        asmgen.out("""
-$endLabel       inx""")
                     }
+                    asmgen.out("""
+$endLabel       inx""")
                 }
             }
             DataType.ARRAY_W, DataType.ARRAY_UW -> {
@@ -171,45 +115,54 @@ $endLabel       inx""")
 
                     stepsize == 1 || stepsize == -1 -> {
                         asmgen.translateExpression(range.to)
-                        val varname = asmgen.asmIdentifierName(stmt.loopVar!!)
-                        val assignLoopvar = Assignment(AssignTarget(null, stmt.loopVar, null, null, stmt.loopVar!!.position),
-                                null, range.from, range.position)
+                        val varname = asmgen.asmIdentifierName(stmt.loopVar)
+                        val assignLoopvar = Assignment(AssignTarget(stmt.loopVar, null, null, stmt.loopVar.position), range.from, range.position)
                         assignLoopvar.linkParents(stmt)
                         asmgen.translate(assignLoopvar)
-                        asmgen.out(loopLabel)
+                        asmgen.out("""
+                            lda  $ESTACK_HI_PLUS1_HEX,x
+                            sta  $modifiedLabel+1
+                            lda  $ESTACK_LO_PLUS1_HEX,x
+                            sta  $modifiedLabel2+1
+$loopLabel""")
                         asmgen.translate(stmt.body)
                         asmgen.out("""
                 lda  $varname+1
-                cmp  $ESTACK_HI_PLUS1_HEX,x
+$modifiedLabel  cmp  #0    ; modified 
                 bne  +
                 lda  $varname
-                cmp  $ESTACK_LO_PLUS1_HEX,x
+$modifiedLabel2 cmp  #0    ; modified 
                 beq  $endLabel""")
                         if(stepsize==1) {
                             asmgen.out("""
 +               inc  $varname
-                bne  +
-                inc  $varname+1            
+                bne  $loopLabel
+                inc  $varname+1
+                jmp  $loopLabel
                             """)
                         } else {
                             asmgen.out("""
 +               lda  $varname
                 bne  +
                 dec  $varname+1
-+               dec  $varname""")
++               dec  $varname
+                jmp  $loopLabel""")
                         }
-                        asmgen.out("""
-+               jmp  $loopLabel
-$endLabel       inx""")
+                        asmgen.out(endLabel)
+                        asmgen.out(" inx")
                     }
                     stepsize > 0 -> {
 
                         // (u)words, step >= 2
-
                         asmgen.translateExpression(range.to)
-                        val varname = asmgen.asmIdentifierName(stmt.loopVar!!)
-                        val assignLoopvar = Assignment(AssignTarget(null, stmt.loopVar, null, null, stmt.loopVar!!.position),
-                                null, range.from, range.position)
+                        asmgen.out("""
+                            lda  $ESTACK_HI_PLUS1_HEX,x
+                            sta  $modifiedLabel+1
+                            lda  $ESTACK_LO_PLUS1_HEX,x
+                            sta  $modifiedLabel2+1
+                        """)
+                        val varname = asmgen.asmIdentifierName(stmt.loopVar)
+                        val assignLoopvar = Assignment(AssignTarget(stmt.loopVar, null, null, stmt.loopVar.position), range.from, range.position)
                         assignLoopvar.linkParents(stmt)
                         asmgen.translate(assignLoopvar)
                         asmgen.out(loopLabel)
@@ -224,12 +177,11 @@ $endLabel       inx""")
                 lda  $varname+1
                 adc  #>$stepsize
                 sta  $varname+1
-                lda  $ESTACK_HI_PLUS1_HEX,x
-                cmp  $varname+1
-                bcc  $endLabel
-                bne  $loopLabel
-                lda  $varname
-                cmp  $ESTACK_LO_PLUS1_HEX,x
+$modifiedLabel  cmp  #0     ; modified
+                bcc  $loopLabel
+                bne  $endLabel
+$modifiedLabel2 lda  #0     ; modified
+                cmp  $varname
                 bcc  $endLabel
                 bcs  $loopLabel
 $endLabel       inx""")
@@ -242,9 +194,9 @@ $endLabel       inx""")
                 lda  $varname+1
                 adc  #>$stepsize
                 sta  $varname+1
-                lda  $ESTACK_LO_PLUS1_HEX,x
+$modifiedLabel2 lda  #0   ; modified
                 cmp  $varname
-                lda  $ESTACK_HI_PLUS1_HEX,x
+$modifiedLabel  lda  #0   ; modified
                 sbc  $varname+1
                 bvc  +
                 eor  #$80
@@ -256,9 +208,14 @@ $endLabel       inx""")
 
                         // (u)words, step <= -2
                         asmgen.translateExpression(range.to)
-                        val varname = asmgen.asmIdentifierName(stmt.loopVar!!)
-                        val assignLoopvar = Assignment(AssignTarget(null, stmt.loopVar, null, null, stmt.loopVar!!.position),
-                                null, range.from, range.position)
+                        asmgen.out("""
+                            lda  $ESTACK_HI_PLUS1_HEX,x
+                            sta  $modifiedLabel+1
+                            lda  $ESTACK_LO_PLUS1_HEX,x
+                            sta  $modifiedLabel2+1
+                        """)
+                        val varname = asmgen.asmIdentifierName(stmt.loopVar)
+                        val assignLoopvar = Assignment(AssignTarget(stmt.loopVar, null, null, stmt.loopVar.position), range.from, range.position)
                         assignLoopvar.linkParents(stmt)
                         asmgen.translate(assignLoopvar)
                         asmgen.out(loopLabel)
@@ -273,11 +230,11 @@ $endLabel       inx""")
                 lda  $varname+1
                 sbc  #>${stepsize.absoluteValue}
                 sta  $varname+1
-                cmp  $ESTACK_HI_PLUS1_HEX,x
+$modifiedLabel  cmp  #0    ; modified                
                 bcc  $endLabel
                 bne  $loopLabel
                 lda  $varname
-                cmp  $ESTACK_LO_PLUS1_HEX,x
+$modifiedLabel2 cmp  #0    ; modified 
                 bcs  $loopLabel
 $endLabel       inx""")
                         } else {
@@ -291,9 +248,9 @@ $endLabel       inx""")
                 sbc  #>${stepsize.absoluteValue}
                 sta  $varname+1
                 pla
-                cmp  $ESTACK_LO_PLUS1_HEX,x
+$modifiedLabel2 cmp  #0    ; modified 
                 lda  $varname+1
-                sbc  $ESTACK_HI_PLUS1_HEX,x
+$modifiedLabel  sbc  #0    ; modified
                 bvc  +
                 eor  #$80
 +               bpl  $loopLabel                
@@ -306,99 +263,104 @@ $endLabel       inx""")
         }
 
         asmgen.loopEndLabels.pop()
-        asmgen.loopContinueLabels.pop()
     }
 
     private fun translateForOverIterableVar(stmt: ForLoop, iterableDt: DataType, ident: IdentifierReference) {
         val loopLabel = asmgen.makeLabel("for_loop")
         val endLabel = asmgen.makeLabel("for_end")
-        val continueLabel = asmgen.makeLabel("for_continue")
         asmgen.loopEndLabels.push(endLabel)
-        asmgen.loopContinueLabels.push(continueLabel)
         val iterableName = asmgen.asmIdentifierName(ident)
         val decl = ident.targetVarDecl(program.namespace)!!
         when(iterableDt) {
             DataType.STR -> {
-                if(stmt.loopRegister!=null && stmt.loopRegister!= Register.A)
-                    throw AssemblyError("can only use A")
                 asmgen.out("""
                     lda  #<$iterableName
                     ldy  #>$iterableName
                     sta  $loopLabel+1
                     sty  $loopLabel+2
 $loopLabel          lda  ${65535.toHex()}       ; modified
-                    beq  $endLabel""")
-                if(stmt.loopVar!=null)
-                    asmgen.out("  sta  ${asmgen.asmIdentifierName(stmt.loopVar!!)}")
+                    beq  $endLabel
+                    sta  ${asmgen.asmIdentifierName(stmt.loopVar)}""")
                 asmgen.translate(stmt.body)
                 asmgen.out("""
-$continueLabel      inc  $loopLabel+1
+                    inc  $loopLabel+1
                     bne  $loopLabel
                     inc  $loopLabel+2
                     bne  $loopLabel
 $endLabel""")
             }
             DataType.ARRAY_UB, DataType.ARRAY_B -> {
-                // TODO: optimize loop code when the length of the array is < 256, don't need a separate counter in such cases
                 val length = decl.arraysize!!.size()!!
-                if(stmt.loopRegister!=null && stmt.loopRegister!= Register.A)
-                    throw AssemblyError("can only use A")
-                val counterLabel = asmgen.makeLabel("for_counter")
-                val modifiedLabel = asmgen.makeLabel("for_modified")
+                val indexVar = asmgen.makeLabel("for_index")
                 asmgen.out("""
-                    lda  #<$iterableName
-                    ldy  #>$iterableName
-                    sta  $modifiedLabel+1
-                    sty  $modifiedLabel+2
                     ldy  #0
-$loopLabel          sty  $counterLabel
-$modifiedLabel      lda  ${65535.toHex()},y       ; modified""")
-                if(stmt.loopVar!=null)
-                    asmgen.out("  sta  ${asmgen.asmIdentifierName(stmt.loopVar!!)}")
+$loopLabel          sty  $indexVar
+                    lda  $iterableName,y
+                    sta  ${asmgen.asmIdentifierName(stmt.loopVar)}""")
                 asmgen.translate(stmt.body)
-                asmgen.out("""
-$continueLabel      ldy  $counterLabel
-                    iny
-                    cpy  #${length and 255}
-                    beq  $endLabel
-                    jmp  $loopLabel
-$counterLabel       .byte  0
-$endLabel""")
+                if(length<=255) {
+                    asmgen.out("""
+                        ldy  $indexVar
+                        iny
+                        cpy  #$length
+                        beq  $endLabel
+                        bne  $loopLabel""")
+                } else {
+                    // length is 256
+                    asmgen.out("""
+                        ldy  $indexVar
+                        iny
+                        bne  $loopLabel
+                        beq  $endLabel""")
+                }
+                if(length>=16 && asmgen.zeropage.available() > 0) {
+                    // allocate index var on ZP
+                    val zpAddr = asmgen.zeropage.allocate(indexVar, DataType.UBYTE, stmt.position, asmgen.errors)
+                    asmgen.out("""$indexVar = $zpAddr  ; auto zp UBYTE""")
+                } else {
+                    asmgen.out("""
+$indexVar           .byte  0""")
+                }
+                asmgen.out(endLabel)
             }
             DataType.ARRAY_W, DataType.ARRAY_UW -> {
-                // TODO: optimize loop code when the length of the array is < 256, don't need a separate counter in such cases
                 val length = decl.arraysize!!.size()!! * 2
-                if(stmt.loopRegister!=null)
-                    throw AssemblyError("can't use register to loop over words")
-                val counterLabel = asmgen.makeLabel("for_counter")
-                val modifiedLabel = asmgen.makeLabel("for_modified")
-                val modifiedLabel2 = asmgen.makeLabel("for_modified2")
-                val loopvarName = asmgen.asmIdentifierName(stmt.loopVar!!)
+                val indexVar = asmgen.makeLabel("for_index")
+                val loopvarName = asmgen.asmIdentifierName(stmt.loopVar)
                 asmgen.out("""
-                    lda  #<$iterableName
-                    ldy  #>$iterableName
-                    sta  $modifiedLabel+1
-                    sty  $modifiedLabel+2
-                    lda  #<$iterableName+1
-                    ldy  #>$iterableName+1
-                    sta  $modifiedLabel2+1
-                    sty  $modifiedLabel2+2
                     ldy  #0
-$loopLabel          sty  $counterLabel
-$modifiedLabel      lda  ${65535.toHex()},y       ; modified
+$loopLabel          sty  $indexVar
+                    lda  $iterableName,y
                     sta  $loopvarName
-$modifiedLabel2     lda  ${65535.toHex()},y       ; modified
+                    lda  $iterableName+1,y
                     sta  $loopvarName+1""")
                 asmgen.translate(stmt.body)
-                asmgen.out("""
-$continueLabel      ldy  $counterLabel
-                    iny
-                    iny
-                    cpy  #${length and 255}
-                    beq  $endLabel
-                    jmp  $loopLabel
-$counterLabel       .byte  0
-$endLabel""")
+                if(length<=127) {
+                    asmgen.out("""
+                        ldy  $indexVar
+                        iny
+                        iny
+                        cpy  #$length
+                        beq  $endLabel
+                        bne  $loopLabel""")
+                } else {
+                    // length is 128 words, 256 bytes
+                    asmgen.out("""
+                        ldy  $indexVar
+                        iny
+                        iny
+                        bne  $loopLabel
+                        beq  $endLabel""")
+                }
+                if(length>=16 && asmgen.zeropage.available() > 0) {
+                    // allocate index var on ZP
+                    val zpAddr = asmgen.zeropage.allocate(indexVar, DataType.UBYTE, stmt.position, asmgen.errors)
+                    asmgen.out("""$indexVar = $zpAddr  ; auto zp UBYTE""")
+                } else {
+                    asmgen.out("""
+$indexVar           .byte  0""")
+                }
+                asmgen.out(endLabel)
             }
             DataType.ARRAY_F -> {
                 throw AssemblyError("for loop with floating point variables is not supported")
@@ -406,287 +368,123 @@ $endLabel""")
             else -> throw AssemblyError("can't iterate over $iterableDt")
         }
         asmgen.loopEndLabels.pop()
-        asmgen.loopContinueLabels.pop()
     }
 
     private fun translateForOverConstRange(stmt: ForLoop, iterableDt: DataType, range: IntProgression) {
-        // TODO: optimize loop code when the range is < 256 iterations, don't need a separate counter in such cases
-        if (range.isEmpty())
-            throw AssemblyError("empty range")
+        if (range.isEmpty() || range.step==0)
+            throw AssemblyError("empty range or step 0")
+        if(iterableDt==DataType.ARRAY_B || iterableDt==DataType.ARRAY_UB) {
+            if(range.step==1 && range.last>range.first) return translateForSimpleByteRangeAsc(stmt, range)
+            if(range.step==-1 && range.last<range.first) return translateForSimpleByteRangeDesc(stmt, range)
+        }
+        else if(iterableDt==DataType.ARRAY_W || iterableDt==DataType.ARRAY_UW) {
+            if(range.step==1 && range.last>range.first) return translateForSimpleWordRangeAsc(stmt, range)
+            if(range.step==-1 && range.last<range.first) return translateForSimpleWordRangeDesc(stmt, range)
+        }
+
+        // not one of the easy cases, generate more complex code...
         val loopLabel = asmgen.makeLabel("for_loop")
         val endLabel = asmgen.makeLabel("for_end")
-        val continueLabel = asmgen.makeLabel("for_continue")
         asmgen.loopEndLabels.push(endLabel)
-        asmgen.loopContinueLabels.push(continueLabel)
         when(iterableDt) {
             DataType.ARRAY_B, DataType.ARRAY_UB -> {
-                val counterLabel = asmgen.makeLabel("for_counter")
-                if(stmt.loopRegister!=null) {
-
-                    // loop register over range
-
-                    if(stmt.loopRegister!= Register.A)
-                        throw AssemblyError("can only use A")
-                    when {
-                        range.step==1 -> {
-                            // step = 1
+                // loop over byte range via loopvar, step >= 2 or <= -2
+                val varname = asmgen.asmIdentifierName(stmt.loopVar)
+                asmgen.out("""
+                            lda  #${range.first}
+                            sta  $varname
+$loopLabel""")
+                asmgen.translate(stmt.body)
+                when (range.step) {
+                    0, 1, -1 -> {
+                        throw AssemblyError("step 0, 1 and -1 should have been handled specifically  $stmt")
+                    }
+                    2 -> {
+                        if(range.last==255) {
                             asmgen.out("""
-                lda  #${range.first}
-                sta  $loopLabel+1
-                lda  #${range.last-range.first+1 and 255}
-                sta  $counterLabel
-$loopLabel      lda  #0                 ; modified""")
-                            asmgen.translate(stmt.body)
+                                inc  $varname
+                                beq  $endLabel
+                                inc  $varname
+                                bne  $loopLabel""")
+                        } else {
                             asmgen.out("""
-$continueLabel  dec  $counterLabel
-                beq  $endLabel
-                inc  $loopLabel+1
-                jmp  $loopLabel
-$counterLabel   .byte  0                
-$endLabel""")
-                        }
-                        range.step==-1 -> {
-                            // step = -1
-                            asmgen.out("""
-                lda  #${range.first}
-                sta  $loopLabel+1
-                lda  #${range.first-range.last+1 and 255}
-                sta  $counterLabel
-$loopLabel      lda  #0                 ; modified """)
-                            asmgen.translate(stmt.body)
-                            asmgen.out("""
-$continueLabel  dec  $counterLabel
-                beq  $endLabel
-                dec  $loopLabel+1
-                jmp  $loopLabel
-$counterLabel   .byte  0                
-$endLabel""")
-                        }
-                        range.step >= 2 -> {
-                            // step >= 2
-                            asmgen.out("""
-                lda  #${(range.last-range.first) / range.step + 1}
-                sta  $counterLabel
-                lda  #${range.first}
-$loopLabel      pha""")
-                            asmgen.translate(stmt.body)
-                            asmgen.out("""
-$continueLabel  pla
-                dec  $counterLabel
-                beq  $endLabel
-                clc
-                adc  #${range.step}
-                jmp  $loopLabel
-$counterLabel   .byte  0                
-$endLabel""")
-                        }
-                        else -> {
-                            // step <= -2
-                            asmgen.out("""
-                lda  #${(range.first-range.last) / range.step.absoluteValue + 1}
-                sta  $counterLabel
-                lda  #${range.first}
-$loopLabel      pha""")
-                            asmgen.translate(stmt.body)
-                            asmgen.out("""
-$continueLabel  pla
-                dec  $counterLabel
-                beq  $endLabel
-                sec
-                sbc  #${range.step.absoluteValue}
-                jmp  $loopLabel
-$counterLabel   .byte  0                
-$endLabel""")
+                                lda  $varname
+                                cmp  #${range.last}
+                                beq  $endLabel
+                                inc  $varname
+                                inc  $varname
+                                jmp  $loopLabel""")
                         }
                     }
-
-                } else {
-
-                    // loop over byte range via loopvar
-                    val varname = asmgen.asmIdentifierName(stmt.loopVar!!)
-                    when {
-                        range.step==1 -> {
-                            // step = 1
-                            asmgen.out("""
-                lda  #${range.first}
-                sta  $varname
-                lda  #${range.last-range.first+1 and 255}
-                sta  $counterLabel
-$loopLabel""")
-                            asmgen.translate(stmt.body)
-                            asmgen.out("""
-$continueLabel  dec  $counterLabel
-                beq  $endLabel
-                inc  $varname
-                jmp  $loopLabel
-$counterLabel   .byte  0                
-$endLabel""")
+                    -2 -> {
+                        when (range.last) {
+                            0 -> asmgen.out("""
+                                lda  $varname
+                                beq  $endLabel
+                                dec  $varname
+                                dec  $varname
+                                jmp  $loopLabel""")
+                            1 -> asmgen.out("""
+                                dec  $varname
+                                beq  $endLabel
+                                dec  $varname
+                                bne  $loopLabel""")
+                            else -> asmgen.out("""
+                                lda  $varname
+                                cmp  #${range.last}
+                                beq  $endLabel
+                                dec  $varname
+                                dec  $varname
+                                jmp  $loopLabel""")
                         }
-                        range.step==-1 -> {
-                            // step = -1
-                            asmgen.out("""
-                lda  #${range.first}
-                sta  $varname
-                lda  #${range.first-range.last+1 and 255}
-                sta  $counterLabel
-$loopLabel""")
-                            asmgen.translate(stmt.body)
-                            asmgen.out("""
-$continueLabel  dec  $counterLabel
-                beq  $endLabel
-                dec  $varname
-                jmp  $loopLabel
-$counterLabel   .byte  0                
-$endLabel""")
-                        }
-                        range.step >= 2 -> {
-                            // step >= 2
-                            asmgen.out("""
-                lda  #${(range.last-range.first) / range.step + 1}
-                sta  $counterLabel
-                lda  #${range.first}
-                sta  $varname
-$loopLabel""")
-                            asmgen.translate(stmt.body)
-                            asmgen.out("""
-$continueLabel  dec  $counterLabel
-                beq  $endLabel
-                lda  $varname
-                clc
-                adc  #${range.step}
-                sta  $varname
-                jmp  $loopLabel
-$counterLabel   .byte  0                
-$endLabel""")
-                        }
-                        else -> {
-                            // step <= -2
-                            asmgen.out("""
-                lda  #${(range.first-range.last) / range.step.absoluteValue + 1}
-                sta  $counterLabel
-                lda  #${range.first}
-                sta  $varname
-$loopLabel""")
-                            asmgen.translate(stmt.body)
-                            asmgen.out("""
-$continueLabel  dec  $counterLabel
-                beq  $endLabel
-                lda  $varname
-                sec
-                sbc  #${range.step.absoluteValue}
-                sta  $varname
-                jmp  $loopLabel
-$counterLabel   .byte  0                
-$endLabel""")
-                        }
-                    }
-                }
-            }
-            DataType.ARRAY_W, DataType.ARRAY_UW -> {
-                // loop over word range via loopvar
-                val varname = asmgen.asmIdentifierName(stmt.loopVar!!)
-                when {
-                    range.step == 1 -> {
-                        // word, step = 1
-                        val lastValue = range.last+1
-                        asmgen.out("""
-                lda  #<${range.first}
-                ldy  #>${range.first}
-                sta  $varname
-                sty  $varname+1
-$loopLabel""")
-                        asmgen.translate(stmt.body)
-                        asmgen.out("""
-$continueLabel  inc  $varname
-                bne  +
-                inc  $varname+1
-+               lda  $varname
-                cmp  #<$lastValue
-                bne  +
-                lda  $varname+1
-                cmp  #>$lastValue
-                beq  $endLabel
-+               jmp  $loopLabel
-$endLabel""")
-                    }
-                    range.step == -1 -> {
-                        // word, step = 1
-                        val lastValue = range.last-1
-                        asmgen.out("""
-                lda  #<${range.first}
-                ldy  #>${range.first}
-                sta  $varname
-                sty  $varname+1
-$loopLabel""")
-                        asmgen.translate(stmt.body)
-                        asmgen.out("""
-$continueLabel  lda  $varname
-                bne  +
-                dec  $varname+1
-+               dec  $varname
-                lda  $varname
-                cmp  #<$lastValue
-                bne  +
-                lda  $varname+1
-                cmp  #>$lastValue
-                beq  $endLabel
-+               jmp  $loopLabel
-$endLabel""")
-                    }
-                    range.step >= 2 -> {
-                        // word, step >= 2
-                        // note: range.last has already been adjusted by kotlin itself to actually be the last value of the sequence
-                        val lastValue = range.last+range.step
-                        asmgen.out("""
-                lda  #<${range.first}
-                ldy  #>${range.first}
-                sta  $varname
-                sty  $varname+1
-$loopLabel""")
-                        asmgen.translate(stmt.body)
-                        asmgen.out("""
-$continueLabel  clc
-                lda  $varname
-                adc  #<${range.step}
-                sta  $varname
-                lda  $varname+1
-                adc  #>${range.step}
-                sta  $varname+1
-                lda  $varname
-                cmp  #<$lastValue
-                bne  +
-                lda  $varname+1
-                cmp  #>$lastValue
-                beq  $endLabel
-+               jmp  $loopLabel
-$endLabel""")
                     }
                     else -> {
-                        // step <= -2
-                        // note: range.last has already been adjusted by kotlin itself to actually be the last value of the sequence
-                        val lastValue = range.last+range.step
+                        // step <= -3 or >= 3
                         asmgen.out("""
-                lda  #<${range.first}
-                ldy  #>${range.first}
-                sta  $varname
-                sty  $varname+1
+                            lda  $varname
+                            cmp  #${range.last}
+                            beq  $endLabel
+                            clc
+                            adc  #${range.step}
+                            sta  $varname
+                            jmp  $loopLabel""")
+                    }
+                }
+                asmgen.out(endLabel)
+            }
+            DataType.ARRAY_W, DataType.ARRAY_UW -> {
+                // loop over word range via loopvar, step >= 2 or <= -2
+                val varname = asmgen.asmIdentifierName(stmt.loopVar)
+                when (range.step) {
+                    0, 1, -1 -> {
+                        throw AssemblyError("step 0, 1 and -1 should have been handled specifically  $stmt")
+                    }
+                    else -> {
+                        // word, step >= 2 or <= -2
+                        // note: range.last has already been adjusted by kotlin itself to actually be the last value of the sequence
+                        asmgen.out("""
+                            lda  #<${range.first}
+                            ldy  #>${range.first}
+                            sta  $varname
+                            sty  $varname+1
 $loopLabel""")
                         asmgen.translate(stmt.body)
                         asmgen.out("""
-$continueLabel  sec
-                lda  $varname
-                sbc  #<${range.step.absoluteValue}
-                sta  $varname
-                lda  $varname+1
-                sbc  #>${range.step.absoluteValue}
-                sta  $varname+1
-                lda  $varname
-                cmp  #<$lastValue
-                bne  +
-                lda  $varname+1
-                cmp  #>$lastValue
-                beq  $endLabel
-+               jmp  $loopLabel
+                            lda  $varname
+                            cmp  #<${range.last}
+                            bne  +
+                            lda  $varname+1
+                            cmp  #>${range.last}
+                            bne  +
+                            beq  $endLabel
++                           lda  $varname
+                            clc
+                            adc  #<${range.step}
+                            sta  $varname
+                            lda  $varname+1
+                            adc  #>${range.step}
+                            sta  $varname+1
+                            jmp  $loopLabel
 $endLabel""")
                     }
                 }
@@ -694,7 +492,127 @@ $endLabel""")
             else -> throw AssemblyError("range expression can only be byte or word")
         }
         asmgen.loopEndLabels.pop()
-        asmgen.loopContinueLabels.pop()
     }
 
+    private fun translateForSimpleByteRangeAsc(stmt: ForLoop, range: IntProgression) {
+        val loopLabel = asmgen.makeLabel("for_loop")
+        val endLabel = asmgen.makeLabel("for_end")
+        asmgen.loopEndLabels.push(endLabel)
+        val varname = asmgen.asmIdentifierName(stmt.loopVar)
+        asmgen.out("""
+                lda  #${range.first}
+                sta  $varname
+$loopLabel""")
+        asmgen.translate(stmt.body)
+        if (range.last == 255) {
+            asmgen.out("""
+                inc  $varname
+                bne  $loopLabel
+$endLabel""")
+        } else {
+            asmgen.out("""
+                lda  $varname
+                cmp  #${range.last}
+                beq  $endLabel
+                inc  $varname
+                jmp  $loopLabel
+$endLabel""")
+        }
+        asmgen.loopEndLabels.pop()
+    }
+
+    private fun translateForSimpleByteRangeDesc(stmt: ForLoop, range: IntProgression) {
+        val loopLabel = asmgen.makeLabel("for_loop")
+        val endLabel = asmgen.makeLabel("for_end")
+        asmgen.loopEndLabels.push(endLabel)
+        val varname = asmgen.asmIdentifierName(stmt.loopVar)
+        asmgen.out("""
+                    lda  #${range.first}
+                    sta  $varname
+$loopLabel""")
+        asmgen.translate(stmt.body)
+        when (range.last) {
+            0 -> {
+                asmgen.out("""
+                    lda  $varname
+                    beq  $endLabel
+                    dec  $varname
+                    jmp  $loopLabel
+$endLabel""")
+            }
+            1 -> {
+                asmgen.out("""
+                    dec  $varname
+                    jmp  $loopLabel
+$endLabel""")
+            }
+            else -> {
+                asmgen.out("""
+                    lda  $varname
+                    cmp  #${range.last}
+                    beq  $endLabel
+                    dec  $varname
+                    jmp  $loopLabel
+$endLabel""")
+            }
+        }
+        asmgen.loopEndLabels.pop()
+    }
+
+    private fun translateForSimpleWordRangeAsc(stmt: ForLoop, range: IntProgression) {
+        val loopLabel = asmgen.makeLabel("for_loop")
+        val endLabel = asmgen.makeLabel("for_end")
+        asmgen.loopEndLabels.push(endLabel)
+        val varname = asmgen.asmIdentifierName(stmt.loopVar)
+        asmgen.out("""
+            lda  #<${range.first}
+            ldy  #>${range.first}
+            sta  $varname
+            sty  $varname+1
+$loopLabel""")
+        asmgen.translate(stmt.body)
+        asmgen.out("""
+            lda  $varname
+            cmp  #<${range.last}
+            bne  +
+            lda  $varname+1
+            cmp  #>${range.last}
+            bne  +
+            beq  $endLabel
++           inc  $varname
+            bne  $loopLabel
+            inc  $varname+1
+            jmp  $loopLabel
+$endLabel""")
+        asmgen.loopEndLabels.pop()
+    }
+
+    private fun translateForSimpleWordRangeDesc(stmt: ForLoop, range: IntProgression) {
+        val loopLabel = asmgen.makeLabel("for_loop")
+        val endLabel = asmgen.makeLabel("for_end")
+        asmgen.loopEndLabels.push(endLabel)
+        val varname = asmgen.asmIdentifierName(stmt.loopVar)
+        asmgen.out("""
+            lda  #<${range.first}
+            ldy  #>${range.first}
+            sta  $varname
+            sty  $varname+1
+$loopLabel""")
+        asmgen.translate(stmt.body)
+        asmgen.out("""
+            lda  $varname
+            cmp  #<${range.last}
+            bne  +
+            lda  $varname+1
+            cmp  #>${range.last}
+            bne  +
+            beq  $endLabel
++           lda  $varname
+            bne  +
+            dec  $varname+1
++           dec  $varname
+            jmp  $loopLabel
+$endLabel""")
+        asmgen.loopEndLabels.pop()
+    }
 }

compiler/src/prog8/compiler/target/c64/codegen/FunctionCallAsmGen.kt

@@ -5,6 +5,7 @@ import prog8.ast.Program
 import prog8.ast.base.*
 import prog8.ast.expressions.*
 import prog8.ast.statements.AssignTarget
+import prog8.ast.statements.Assignment
 import prog8.ast.statements.Subroutine
 import prog8.ast.statements.SubroutineParameter
 import prog8.compiler.AssemblyError
@@ -19,14 +20,42 @@ internal class FunctionCallAsmGen(private val program: Program, private val asmg
         // output the code to setup the parameters and perform the actual call
         // does NOT output the code to deal with the result values!
         val sub = stmt.target.targetSubroutine(program.namespace) ?: throw AssemblyError("undefined subroutine ${stmt.target}")
-        val saveX = Register.X in sub.asmClobbers || sub.regXasResult()
+        val saveX = CpuRegister.X in sub.asmClobbers || sub.regXasResult()
         if(saveX)
             asmgen.out("  stx  c64.SCRATCH_ZPREGX")        // we only save X for now (required! is the eval stack pointer), screw A and Y...
 
         val subName = asmgen.asmIdentifierName(stmt.target)
         if(stmt.args.isNotEmpty()) {
-            for(arg in sub.parameters.withIndex().zip(stmt.args)) {
-                translateFuncArguments(arg.first, arg.second, sub)
+            if(sub.asmParameterRegisters.isEmpty()) {
+                // via variables
+                for(arg in sub.parameters.withIndex().zip(stmt.args)) {
+                    argumentViaVariable(sub, arg.first, arg.second)
+                }
+            } else {
+                // via registers
+                if(sub.parameters.size==1) {
+                    // just a single parameter, no risk of clobbering registers
+                    argumentViaRegister(sub, sub.parameters.withIndex().single(), stmt.args[0])
+                } else {
+                    // multiple register arguments, risk of register clobbering.
+                    // evaluate arguments onto the stack, and load the registers from the evaluated values on the stack.
+                    when {
+                        stmt.args.all {it is AddressOf ||
+                                it is NumericLiteralValue ||
+                                it is StringLiteralValue ||
+                                it is ArrayLiteralValue ||
+                                it is IdentifierReference} -> {
+                            // no risk of clobbering for these simple argument types. Optimize the register loading.
+                            for(arg in sub.parameters.withIndex().zip(stmt.args)) {
+                                argumentViaRegister(sub, arg.first, arg.second)
+                            }
+                        }
+                        else -> {
+                            // Risk of clobbering due to complex expression args. Work via the stack.
+                            argsViaStackEvaluation(stmt, sub)
+                        }
+                    }
+                }
             }
         }
         asmgen.out("  jsr  $subName")
@@ -35,197 +64,178 @@ internal class FunctionCallAsmGen(private val program: Program, private val asmg
             asmgen.out("  ldx  c64.SCRATCH_ZPREGX")        // restore X again
     }
 
-    private fun translateFuncArguments(parameter: IndexedValue<SubroutineParameter>, value: Expression, sub: Subroutine) {
-        val sourceIDt = value.inferType(program)
-        if(!sourceIDt.isKnown)
-            throw AssemblyError("arg type unknown")
-        val sourceDt = sourceIDt.typeOrElse(DataType.STRUCT)
-        if(!argumentTypeCompatible(sourceDt, parameter.value.type))
-            throw AssemblyError("argument type incompatible")
-        if(sub.asmParameterRegisters.isEmpty()) {
-            // pass parameter via a regular variable (not via registers)
-            val paramVar = parameter.value
-            val scopedParamVar = (sub.scopedname+"."+paramVar.name).split(".")
-            val target = AssignTarget(null, IdentifierReference(scopedParamVar, sub.position), null, null, sub.position)
-            target.linkParents(value.parent)
-            when (value) {
-                is NumericLiteralValue -> {
-                    // optimize when the argument is a constant literal
-                    when(parameter.value.type) {
-                        in ByteDatatypes -> asmgen.assignFromByteConstant(target, value.number.toShort())
-                        in WordDatatypes -> asmgen.assignFromWordConstant(target, value.number.toInt())
-                        DataType.FLOAT -> asmgen.assignFromFloatConstant(target, value.number.toDouble())
-                        in PassByReferenceDatatypes -> throw AssemblyError("can't pass string/array as argument via a variable?")    // TODO huh
-                        else -> throw AssemblyError("weird parameter datatype")
-                    }
-                }
-                is IdentifierReference -> {
-                    // optimize when the argument is a variable
-                    when (parameter.value.type) {
-                        in ByteDatatypes -> asmgen.assignFromByteVariable(target, value)
-                        in WordDatatypes -> asmgen.assignFromWordVariable(target, value)
-                        DataType.FLOAT -> asmgen.assignFromFloatVariable(target, value)
-                        in PassByReferenceDatatypes -> throw AssemblyError("can't pass string/array as argument via a variable?")     // TODO huh
-                        else -> throw AssemblyError("weird parameter datatype")
-                    }
-                }
-                is RegisterExpr -> {
-                    asmgen.assignFromRegister(target, value.register)
-                }
-                is DirectMemoryRead -> {
-                    when(value.addressExpression) {
-                        is NumericLiteralValue -> {
-                            val address = (value.addressExpression as NumericLiteralValue).number.toInt()
-                            asmgen.assignFromMemoryByte(target, address, null)
-                        }
-                        is IdentifierReference -> {
-                            asmgen.assignFromMemoryByte(target, null, value.addressExpression as IdentifierReference)
-                        }
-                        else -> {
-                            asmgen.translateExpression(value.addressExpression)
-                            asmgen.out("  jsr  prog8_lib.read_byte_from_address |  inx")
-                            asmgen.assignFromRegister(target, Register.A)
-                        }
-                    }
-                }
-                else -> {
-                    asmgen.translateExpression(value)
-                    asmgen.assignFromEvalResult(target)
+    private fun argsViaStackEvaluation(stmt: IFunctionCall, sub: Subroutine) {
+        for (arg in stmt.args.reversed())
+            asmgen.translateExpression(arg)
+        for (regparam in sub.asmParameterRegisters) {
+            when (regparam.registerOrPair) {
+                RegisterOrPair.A -> asmgen.out(" inx |  lda  $ESTACK_LO_HEX,x")
+                RegisterOrPair.X -> throw AssemblyError("can't pop into X register - use a variable instead")
+                RegisterOrPair.Y -> asmgen.out(" inx |  ldy  $ESTACK_LO_HEX,x")
+                RegisterOrPair.AX -> throw AssemblyError("can't pop into X register - use a variable instead")
+                RegisterOrPair.AY -> asmgen.out(" inx |  lda  $ESTACK_LO_HEX,x |  ldy  $ESTACK_HI_HEX,x")
+                RegisterOrPair.XY -> throw AssemblyError("can't pop into X register - use a variable instead")
+                null -> {
                 }
             }
-        } else {
-            // pass parameter via a register parameter
-            val paramRegister = sub.asmParameterRegisters[parameter.index]
-            val statusflag = paramRegister.statusflag
-            val register = paramRegister.registerOrPair
-            val stack = paramRegister.stack
-            when {
-                stack -> {
-                    // push arg onto the stack
-                    // note: argument order is reversed (first argument will be deepest on the stack)
-                    asmgen.translateExpression(value)
+            when (regparam.statusflag) {
+                Statusflag.Pc -> asmgen.out("""
+                        inx
+                        pha
+                        lda  $ESTACK_LO_HEX,x
+                        beq  +
+                        sec  
+                        bcs  ++
+            +           clc
+            +           pla
+            """)
+                null -> {
                 }
-                statusflag!=null -> {
-                    if (statusflag == Statusflag.Pc) {
-                        // this param needs to be set last, right before the jsr
-                        // for now, this is already enforced on the subroutine definition by the Ast Checker
-                        when(value) {
-                            is NumericLiteralValue -> {
-                                val carrySet = value.number.toInt() != 0
-                                asmgen.out(if(carrySet) "  sec" else "  clc")
-                            }
-                            is IdentifierReference -> {
-                                val sourceName = asmgen.asmIdentifierName(value)
-                                asmgen.out("""
+                else -> throw AssemblyError("can only use Carry as status flag parameter")
+            }
+        }
+    }
+
+    private fun argumentViaVariable(sub: Subroutine, parameter: IndexedValue<SubroutineParameter>, value: Expression) {
+        // pass parameter via a regular variable (not via registers)
+        val valueIDt = value.inferType(program)
+        if(!valueIDt.isKnown)
+            throw AssemblyError("arg type unknown")
+        val valueDt = valueIDt.typeOrElse(DataType.STRUCT)
+        if(!argumentTypeCompatible(valueDt, parameter.value.type))
+            throw AssemblyError("argument type incompatible")
+
+        val paramVar = parameter.value
+        val scopedParamVar = (sub.scopedname+"."+paramVar.name).split(".")
+        val target = AssignTarget(IdentifierReference(scopedParamVar, sub.position), null, null, sub.position)
+        val assign = Assignment(target, value, value.position)
+        assign.linkParents(value.parent)
+        asmgen.translate(assign)
+    }
+
+    private fun argumentViaRegister(sub: Subroutine, parameter: IndexedValue<SubroutineParameter>, value: Expression) {
+        // pass argument via a register parameter
+        val valueIDt = value.inferType(program)
+        if(!valueIDt.isKnown)
+            throw AssemblyError("arg type unknown")
+        val valueDt = valueIDt.typeOrElse(DataType.STRUCT)
+        if(!argumentTypeCompatible(valueDt, parameter.value.type))
+            throw AssemblyError("argument type incompatible")
+
+        val paramRegister = sub.asmParameterRegisters[parameter.index]
+        val statusflag = paramRegister.statusflag
+        val register = paramRegister.registerOrPair
+        val stack = paramRegister.stack
+        when {
+            stack -> {
+                // push arg onto the stack
+                // note: argument order is reversed (first argument will be deepest on the stack)
+                asmgen.translateExpression(value)
+            }
+            statusflag!=null -> {
+                if (statusflag == Statusflag.Pc) {
+                    // this param needs to be set last, right before the jsr
+                    // for now, this is already enforced on the subroutine definition by the Ast Checker
+                    when(value) {
+                        is NumericLiteralValue -> {
+                            val carrySet = value.number.toInt() != 0
+                            asmgen.out(if(carrySet) "  sec" else "  clc")
+                        }
+                        is IdentifierReference -> {
+                            val sourceName = asmgen.asmIdentifierName(value)
+                            asmgen.out("""
+            pha
             lda  $sourceName
             beq  +
             sec  
             bcs  ++
 +           clc
-+
++           pla
 """)
-                            }
-                            is RegisterExpr -> {
-                                when(value.register) {
-                                    Register.A -> asmgen.out("  cmp  #0")
-                                    Register.X -> asmgen.out("  txa")
-                                    Register.Y -> asmgen.out("  tya")
-                                }
-                                asmgen.out("""
-            beq  +
-            sec
-            bcs  ++
-+           clc
-+
-""")
-                            }
-                            else -> {
-                                asmgen.translateExpression(value)
-                                asmgen.out("""
-            inx                        
+                        }
+                        else -> {
+                            asmgen.translateExpression(value)
+                            asmgen.out("""
+            inx
+            pha
             lda  $ESTACK_LO_HEX,x
             beq  +
             sec  
             bcs  ++
 +           clc
-+
++           pla
 """)
-                            }
-                        }
-                    }
-                    else throw AssemblyError("can only use Carry as status flag parameter")
-                }
-                register!=null && register.name.length==1 -> {
-                    when (value) {
-                        is NumericLiteralValue -> {
-                            val target = AssignTarget(Register.valueOf(register.name), null, null, null, sub.position)
-                            target.linkParents(value.parent)
-                            asmgen.assignFromByteConstant(target, value.number.toShort())
-                        }
-                        is IdentifierReference -> {
-                            val target = AssignTarget(Register.valueOf(register.name), null, null, null, sub.position)
-                            target.linkParents(value.parent)
-                            asmgen.assignFromByteVariable(target, value)
-                        }
-                        else -> {
-                            asmgen.translateExpression(value)
-                            when(register) {
-                                RegisterOrPair.A -> asmgen.out("  inx | lda  $ESTACK_LO_HEX,x")
-                                RegisterOrPair.X -> throw AssemblyError("can't pop into X register - use a variable instead")
-                                RegisterOrPair.Y -> asmgen.out("  inx | ldy  $ESTACK_LO_HEX,x")
-                                else -> throw AssemblyError("cannot assign to register pair")
-                            }
                         }
                     }
                 }
-                register!=null && register.name.length==2 -> {
-                    // register pair as a 16-bit value (only possible for subroutine parameters)
-                    when (value) {
-                        is NumericLiteralValue -> {
-                            // optimize when the argument is a constant literal
-                            val hex = value.number.toHex()
-                            when (register) {
-                                RegisterOrPair.AX -> asmgen.out("  lda  #<$hex  |  ldx  #>$hex")
-                                RegisterOrPair.AY -> asmgen.out("  lda  #<$hex  |  ldy  #>$hex")
-                                RegisterOrPair.XY -> asmgen.out("  ldx  #<$hex  |  ldy  #>$hex")
-                                else -> {}
-                            }
+                else throw AssemblyError("can only use Carry as status flag parameter")
+            }
+            register!=null && register.name.length==1 -> {
+                when (value) {
+                    is NumericLiteralValue -> {
+                        asmgen.assignToRegister(CpuRegister.valueOf(register.name), value.number.toShort(), null)
+                    }
+                    is IdentifierReference -> {
+                        asmgen.assignToRegister(CpuRegister.valueOf(register.name), null, value)
+                    }
+                    else -> {
+                        asmgen.translateExpression(value)
+                        when(register) {
+                            RegisterOrPair.A -> asmgen.out("  inx | lda  $ESTACK_LO_HEX,x")
+                            RegisterOrPair.X -> throw AssemblyError("can't pop into X register - use a variable instead")
+                            RegisterOrPair.Y -> asmgen.out("  inx | ldy  $ESTACK_LO_HEX,x")
+                            else -> throw AssemblyError("cannot assign to register pair")
                         }
-                        is AddressOf -> {
-                            // optimize when the argument is an address of something
-                            val sourceName = asmgen.asmIdentifierName(value.identifier)
+                    }
+                }
+            }
+            register!=null && register.name.length==2 -> {
+                // register pair as a 16-bit value (only possible for subroutine parameters)
+                when (value) {
+                    is NumericLiteralValue -> {
+                        // optimize when the argument is a constant literal
+                        val hex = value.number.toHex()
+                        when (register) {
+                            RegisterOrPair.AX -> asmgen.out("  lda  #<$hex  |  ldx  #>$hex")
+                            RegisterOrPair.AY -> asmgen.out("  lda  #<$hex  |  ldy  #>$hex")
+                            RegisterOrPair.XY -> asmgen.out("  ldx  #<$hex  |  ldy  #>$hex")
+                            else -> {}
+                        }
+                    }
+                    is AddressOf -> {
+                        // optimize when the argument is an address of something
+                        val sourceName = asmgen.asmIdentifierName(value.identifier)
+                        when (register) {
+                            RegisterOrPair.AX -> asmgen.out("  lda  #<$sourceName  |  ldx  #>$sourceName")
+                            RegisterOrPair.AY -> asmgen.out("  lda  #<$sourceName  |  ldy  #>$sourceName")
+                            RegisterOrPair.XY -> asmgen.out("  ldx  #<$sourceName  |  ldy  #>$sourceName")
+                            else -> {}
+                        }
+                    }
+                    is IdentifierReference -> {
+                        val sourceName = asmgen.asmIdentifierName(value)
+                        if(valueDt in PassByReferenceDatatypes) {
                             when (register) {
                                 RegisterOrPair.AX -> asmgen.out("  lda  #<$sourceName  |  ldx  #>$sourceName")
                                 RegisterOrPair.AY -> asmgen.out("  lda  #<$sourceName  |  ldy  #>$sourceName")
                                 RegisterOrPair.XY -> asmgen.out("  ldx  #<$sourceName  |  ldy  #>$sourceName")
                                 else -> {}
                             }
-                        }
-                        is IdentifierReference -> {
-                            val sourceName = asmgen.asmIdentifierName(value)
-                            if(sourceDt in PassByReferenceDatatypes) {
-                                when (register) {
-                                    RegisterOrPair.AX -> asmgen.out("  lda  #<$sourceName  |  ldx  #>$sourceName")
-                                    RegisterOrPair.AY -> asmgen.out("  lda  #<$sourceName  |  ldy  #>$sourceName")
-                                    RegisterOrPair.XY -> asmgen.out("  ldx  #<$sourceName  |  ldy  #>$sourceName")
-                                    else -> {}
-                                }
-                            } else {
-                                when (register) {
-                                    RegisterOrPair.AX -> asmgen.out("  lda  $sourceName  |  ldx  $sourceName+1")
-                                    RegisterOrPair.AY -> asmgen.out("  lda  $sourceName  |  ldy  $sourceName+1")
-                                    RegisterOrPair.XY -> asmgen.out("  ldx  $sourceName  |  ldy  $sourceName+1")
-                                    else -> {}
-                                }
+                        } else {
+                            when (register) {
+                                RegisterOrPair.AX -> asmgen.out("  lda  $sourceName  |  ldx  $sourceName+1")
+                                RegisterOrPair.AY -> asmgen.out("  lda  $sourceName  |  ldy  $sourceName+1")
+                                RegisterOrPair.XY -> asmgen.out("  ldx  $sourceName  |  ldy  $sourceName+1")
+                                else -> {}
                             }
                         }
-                        else -> {
-                            asmgen.translateExpression(value)
-                            if (register == RegisterOrPair.AX || register == RegisterOrPair.XY)
-                                throw AssemblyError("can't use X register here - use a variable")
-                            else if (register == RegisterOrPair.AY)
-                                asmgen.out("  inx |  lda  $ESTACK_LO_HEX,x  |  ldy  $ESTACK_HI_HEX,x")
-                        }
+                    }
+                    else -> {
+                        asmgen.translateExpression(value)
+                        if (register == RegisterOrPair.AX || register == RegisterOrPair.XY)
+                            throw AssemblyError("can't use X register here - use a variable")
+                        else if (register == RegisterOrPair.AY)
+                            asmgen.out("  inx |  lda  $ESTACK_LO_HEX,x  |  ldy  $ESTACK_HI_HEX,x")
                     }
                 }
             }

compiler/src/prog8/compiler/target/c64/codegen/PostIncrDecrAsmGen.kt

@@ -4,10 +4,11 @@ import prog8.ast.Program
 import prog8.ast.base.*
 import prog8.ast.expressions.IdentifierReference
 import prog8.ast.expressions.NumericLiteralValue
-import prog8.ast.expressions.RegisterExpr
 import prog8.ast.statements.PostIncrDecr
 import prog8.compiler.AssemblyError
 import prog8.compiler.target.c64.C64MachineDefinition.C64Zeropage
+import prog8.compiler.target.c64.C64MachineDefinition.ESTACK_HI_HEX
+import prog8.compiler.target.c64.C64MachineDefinition.ESTACK_LO_HEX
 import prog8.compiler.toHex
 
 
@@ -17,28 +18,10 @@ 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 targetRegister = stmt.target.register
         when {
-            targetRegister!=null -> {
-                when(targetRegister) {
-                    Register.A -> {
-                        if(incr)
-                            asmgen.out("  clc |  adc  #1 ")
-                        else
-                            asmgen.out("  sec |  sbc  #1 ")
-                    }
-                    Register.X -> {
-                        if(incr) asmgen.out("  inx") else asmgen.out("  dex")
-                    }
-                    Register.Y -> {
-                        if(incr) asmgen.out("  iny") else asmgen.out("  dey")
-                    }
-                }
-            }
             targetIdent!=null -> {
                 val what = asmgen.asmIdentifierName(targetIdent)
-                val dt = stmt.target.inferType(program, stmt).typeOrElse(DataType.STRUCT)
-                when (dt) {
+                when (stmt.target.inferType(program, stmt).typeOrElse(DataType.STRUCT)) {
                     in ByteDatatypes -> asmgen.out(if (incr) "  inc  $what" else "  dec  $what")
                     in WordDatatypes -> {
                         if(incr)
@@ -72,7 +55,20 @@ internal class PostIncrDecrAsmGen(private val program: Program, private val asmg
                         else
                             asmgen.out("+\tdec  ${'$'}ffff\t; modified")
                     }
-                    else -> throw AssemblyError("weird target type $targetMemory")
+                    else -> {
+                        asmgen.translateExpression(addressExpr)
+                        asmgen.out("""
+                            inx
+                            lda  $ESTACK_LO_HEX,x
+                            sta  (+) + 1
+                            lda  $ESTACK_HI_HEX,x
+                            sta  (+) + 2
+                        """)
+                        if(incr)
+                            asmgen.out("+\tinc  ${'$'}ffff\t; modified")
+                        else
+                            asmgen.out("+\tdec  ${'$'}ffff\t; modified")
+                    }
                 }
             }
             targetArrayIdx!=null -> {
@@ -103,10 +99,6 @@ internal class PostIncrDecrAsmGen(private val program: Program, private val asmg
                             else -> throw AssemblyError("need numeric type")
                         }
                     }
-                    is RegisterExpr -> {
-                        asmgen.translateArrayIndexIntoA(targetArrayIdx)
-                        incrDecrArrayvalueWithIndexA(incr, arrayDt, what)
-                    }
                     is IdentifierReference -> {
                         asmgen.translateArrayIndexIntoA(targetArrayIdx)
                         incrDecrArrayvalueWithIndexA(incr, arrayDt, what)

compiler/src/prog8/functions/BuiltinFunctions.kt

@@ -3,6 +3,8 @@ package prog8.functions
 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.*
 
@@ -35,6 +37,7 @@ val BuiltinFunctions = mapOf(
     "sum"         to FSignature(true, listOf(FParam("values", ArrayDatatypes)), null) { a, p, prg -> collectionArg(a, p, prg, ::builtinSum) },      // type depends on args
     "abs"         to FSignature(true, listOf(FParam("value", NumericDatatypes)), null, ::builtinAbs),      // type depends on argument
     "len"         to FSignature(true, listOf(FParam("values", IterableDatatypes)), null, ::builtinLen),    // type is UBYTE or UWORD depending on actual length
+    "sizeof"      to FSignature(true, listOf(FParam("object", DataType.values().toSet())), DataType.UBYTE, ::builtinSizeof),
         // normal functions follow:
     "sgn"         to FSignature(true, listOf(FParam("value", NumericDatatypes)), DataType.BYTE, ::builtinSgn ),
     "sin"         to FSignature(true, listOf(FParam("rads", setOf(DataType.FLOAT))), DataType.FLOAT) { a, p, prg -> oneDoubleArg(a, p, prg, Math::sin) },
@@ -103,9 +106,9 @@ val BuiltinFunctions = mapOf(
             FParam("length", setOf(DataType.UBYTE))), null)
 )
 
-fun builtinMax(array: List<Number>): Number = array.maxBy { it.toDouble() }!!
+fun builtinMax(array: List<Number>): Number = array.maxByOrNull { it.toDouble() }!!
 
-fun builtinMin(array: List<Number>): Number = array.minBy { it.toDouble() }!!
+fun builtinMin(array: List<Number>): Number = array.minByOrNull { it.toDouble() }!!
 
 fun builtinSum(array: List<Number>): Number = array.sumByDouble { it.toDouble() }
 
@@ -240,6 +243,42 @@ private fun builtinAbs(args: List<Expression>, position: Position, program: Prog
     }
 }
 
+private fun builtinSizeof(args: List<Expression>, position: Position, program: Program): NumericLiteralValue {
+    // 1 arg, type = anything, result type = ubyte
+    if(args.size!=1)
+        throw SyntaxError("sizeof requires one argument", position)
+    if(args[0] !is IdentifierReference)
+        throw SyntaxError("sizeof argument should be an identifier", position)
+
+    val dt = args[0].inferType(program)
+    if(dt.isKnown) {
+        val target = (args[0] as IdentifierReference).targetStatement(program.namespace)
+                ?: throw CannotEvaluateException("sizeof", "no target")
+
+        fun structSize(target: StructDecl) =
+                NumericLiteralValue(DataType.UBYTE, target.statements.map { (it as VarDecl).datatype.memorySize() }.sum(), position)
+
+        return when {
+            dt.typeOrElse(DataType.STRUCT) in ArrayDatatypes -> {
+                val length = (target as VarDecl).arraysize!!.size() ?: throw CannotEvaluateException("sizeof", "unknown array size")
+                val elementDt = ArrayElementTypes.getValue(dt.typeOrElse(DataType.STRUCT))
+                numericLiteral(elementDt.memorySize() * 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, dt.typeOrElse(DataType.STRUCT).memorySize(), position)
+        }
+    } else {
+        throw SyntaxError("sizeof invalid argument type", position)
+    }
+}
+
 private fun builtinStrlen(args: List<Expression>, position: Position, program: Program): NumericLiteralValue {
     if (args.size != 1)
         throw SyntaxError("strlen requires one argument", position)
@@ -254,9 +293,6 @@ private fun builtinLen(args: List<Expression>, position: Position, program: Prog
     // 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)
-    val constArg = args[0].constValue(program)
-    if(constArg!=null)
-        throw SyntaxError("len of weird argument ${args[0]}", position)
 
     val directMemVar = ((args[0] as? DirectMemoryRead)?.addressExpression as? IdentifierReference)?.targetVarDecl(program.namespace)
     var arraySize = directMemVar?.arraysize?.size()
@@ -265,34 +301,23 @@ private fun builtinLen(args: List<Expression>, position: Position, program: Prog
     if(args[0] is ArrayLiteralValue)
         return NumericLiteralValue.optimalInteger((args[0] as ArrayLiteralValue).value.size, position)
     if(args[0] !is IdentifierReference)
-        throw SyntaxError("len argument should be an identifier, but is ${args[0]}", position)
+        throw SyntaxError("len argument should be an identifier", position)
     val target = (args[0] as IdentifierReference).targetVarDecl(program.namespace)
             ?: throw CannotEvaluateException("len", "no target vardecl")
 
     return when(target.datatype) {
-        DataType.ARRAY_UB, DataType.ARRAY_B, DataType.ARRAY_UW, DataType.ARRAY_W -> {
+        DataType.ARRAY_UB, DataType.ARRAY_B, DataType.ARRAY_UW, DataType.ARRAY_W, DataType.ARRAY_F -> {
             arraySize = target.arraysize?.size()
             if(arraySize==null)
                 throw CannotEvaluateException("len", "arraysize unknown")
-            if(arraySize>256)
-                throw CompilerException("array length exceeds byte limit ${target.position}")
-            NumericLiteralValue.optimalInteger(arraySize, args[0].position)
-        }
-        DataType.ARRAY_F -> {
-            arraySize = target.arraysize?.size()
-            if(arraySize==null)
-                throw CannotEvaluateException("len", "arraysize unknown")
-            if(arraySize>256)
-                throw CompilerException("array length exceeds byte limit ${target.position}")
             NumericLiteralValue.optimalInteger(arraySize, args[0].position)
         }
         DataType.STR -> {
             val refLv = target.value as StringLiteralValue
-            if(refLv.value.length>255)
-                throw CompilerException("string length exceeds byte limit ${refLv.position}")
             NumericLiteralValue.optimalInteger(refLv.value.length, args[0].position)
         }
-        in NumericDatatypes -> throw SyntaxError("len of weird argument ${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")
     }
 }
@@ -312,7 +337,7 @@ private fun builtinSin8(args: List<Expression>, position: Position, program: Pro
         throw SyntaxError("sin8 requires one argument", position)
     val constval = args[0].constValue(program) ?: throw NotConstArgumentException()
     val rad = constval.number.toDouble() /256.0 * 2.0 * PI
-    return NumericLiteralValue(DataType.BYTE, (127.0 * sin(rad)).toShort(), position)
+    return NumericLiteralValue(DataType.BYTE, (127.0 * sin(rad)).toInt().toShort(), position)
 }
 
 private fun builtinSin8u(args: List<Expression>, position: Position, program: Program): NumericLiteralValue {
@@ -320,7 +345,7 @@ private fun builtinSin8u(args: List<Expression>, position: Position, program: Pr
         throw SyntaxError("sin8u requires one argument", position)
     val constval = args[0].constValue(program) ?: throw NotConstArgumentException()
     val rad = constval.number.toDouble() /256.0 * 2.0 * PI
-    return NumericLiteralValue(DataType.UBYTE, (128.0 + 127.5 * sin(rad)).toShort(), position)
+    return NumericLiteralValue(DataType.UBYTE, (128.0 + 127.5 * sin(rad)).toInt().toShort(), position)
 }
 
 private fun builtinCos8(args: List<Expression>, position: Position, program: Program): NumericLiteralValue {
@@ -328,7 +353,7 @@ private fun builtinCos8(args: List<Expression>, position: Position, program: Pro
         throw SyntaxError("cos8 requires one argument", position)
     val constval = args[0].constValue(program) ?: throw NotConstArgumentException()
     val rad = constval.number.toDouble() /256.0 * 2.0 * PI
-    return NumericLiteralValue(DataType.BYTE, (127.0 * cos(rad)).toShort(), position)
+    return NumericLiteralValue(DataType.BYTE, (127.0 * cos(rad)).toInt().toShort(), position)
 }
 
 private fun builtinCos8u(args: List<Expression>, position: Position, program: Program): NumericLiteralValue {
@@ -336,7 +361,7 @@ private fun builtinCos8u(args: List<Expression>, position: Position, program: Pr
         throw SyntaxError("cos8u requires one argument", position)
     val constval = args[0].constValue(program) ?: throw NotConstArgumentException()
     val rad = constval.number.toDouble() /256.0 * 2.0 * PI
-    return NumericLiteralValue(DataType.UBYTE, (128.0 + 127.5 * cos(rad)).toShort(), position)
+    return NumericLiteralValue(DataType.UBYTE, (128.0 + 127.5 * cos(rad)).toInt().toShort(), position)
 }
 
 private fun builtinSin16(args: List<Expression>, position: Position, program: Program): NumericLiteralValue {
@@ -375,7 +400,7 @@ private fun builtinSgn(args: List<Expression>, position: Position, program: Prog
     if (args.size != 1)
         throw SyntaxError("sgn requires one argument", position)
     val constval = args[0].constValue(program) ?: throw NotConstArgumentException()
-    return NumericLiteralValue(DataType.BYTE, constval.number.toDouble().sign.toShort(), position)
+    return NumericLiteralValue(DataType.BYTE, constval.number.toDouble().sign.toInt().toShort(), position)
 }
 
 private fun numericLiteral(value: Number, position: Position): NumericLiteralValue {
@@ -387,8 +412,8 @@ private fun numericLiteral(value: Number, position: Position): NumericLiteralVal
                 floatNum
 
     return when(tweakedValue) {
-        is Int -> NumericLiteralValue.optimalNumeric(value.toInt(), position)
-        is Short -> NumericLiteralValue.optimalNumeric(value.toInt(), position)
+        is Int -> NumericLiteralValue.optimalInteger(value.toInt(), position)
+        is Short -> NumericLiteralValue.optimalInteger(value.toInt(), position)
         is Byte -> NumericLiteralValue(DataType.UBYTE, value.toShort(), position)
         is Double -> NumericLiteralValue(DataType.FLOAT, value.toDouble(), position)
         is Float -> NumericLiteralValue(DataType.FLOAT, value.toDouble(), position)

compiler/src/prog8/optimizer/AssignmentTransformer.kt

@@ -1,157 +0,0 @@
-package prog8.optimizer
-
-import prog8.ast.Node
-import prog8.ast.Program
-import prog8.ast.base.ErrorReporter
-import prog8.ast.expressions.BinaryExpression
-import prog8.ast.processing.AstWalker
-import prog8.ast.processing.IAstModification
-import prog8.ast.statements.Assignment
-import prog8.ast.statements.PostIncrDecr
-
-
-
-internal class AssignmentTransformer(val program: Program, val errors: ErrorReporter) : AstWalker() {
-
-    var optimizationsDone: Int = 0
-    private val noModifications = emptyList<IAstModification>()
-
-    override fun before(assignment: Assignment, parent: Node): Iterable<IAstModification> {
-        // modify A = A + 5 back into augmented form A += 5 for easier code generation for optimized in-place assignments
-        // also to put code generation stuff together, single value assignment (A = 5) is converted to a special
-        // augmented form as wel (with the operator "setvalue")
-        if (assignment.aug_op == null) {
-            val binExpr = assignment.value as? BinaryExpression
-            if (binExpr != null) {
-                if (assignment.target.isSameAs(binExpr.left)) {
-                    assignment.value = binExpr.right
-                    assignment.aug_op = binExpr.operator + "="
-                    assignment.value.parent = assignment
-                    optimizationsDone++
-                    return noModifications
-                }
-            }
-            assignment.aug_op = "setvalue"
-            optimizationsDone++
-        } else if(assignment.aug_op == "+=") {
-            val binExpr = assignment.value as? BinaryExpression
-            if (binExpr != null) {
-                val leftnum = binExpr.left.constValue(program)?.number?.toDouble()
-                val rightnum = binExpr.right.constValue(program)?.number?.toDouble()
-                if(binExpr.operator == "+") {
-                    when {
-                        leftnum == 1.0 -> {
-                            optimizationsDone++
-                            return listOf(IAstModification.SwapOperands(binExpr))
-                        }
-                        leftnum == 2.0 -> {
-                            optimizationsDone++
-                            return listOf(IAstModification.SwapOperands(binExpr))
-                        }
-                        rightnum == 1.0 -> {
-                            // x += y + 1  -> x += y ,  x++
-                            return listOf(
-                                    IAstModification.ReplaceNode(assignment.value, binExpr.left, assignment),
-                                    IAstModification.InsertAfter(assignment, PostIncrDecr(assignment.target, "++", assignment.position), parent)
-                            )
-                        }
-                        rightnum == 2.0 -> {
-                            // x += y + 2  -> x += y ,  x++,  x++
-                            return listOf(
-                                    IAstModification.ReplaceNode(assignment.value, binExpr.left, assignment),
-                                    IAstModification.InsertAfter(assignment, PostIncrDecr(assignment.target, "++", assignment.position), parent),
-                                    IAstModification.InsertAfter(assignment, PostIncrDecr(assignment.target, "++", assignment.position), parent)
-                            )
-                        }
-                    }
-                } else if(binExpr.operator == "-") {
-                    when {
-                        leftnum == 1.0 -> {
-                            optimizationsDone++
-                            return listOf(IAstModification.SwapOperands(binExpr))
-                        }
-                        leftnum == 2.0 -> {
-                            optimizationsDone++
-                            return listOf(IAstModification.SwapOperands(binExpr))
-                        }
-                        rightnum == 1.0 -> {
-                            // x += y - 1  -> x += y ,  x--
-                            return listOf(
-                                    IAstModification.ReplaceNode(assignment.value, binExpr.left, assignment),
-                                    IAstModification.InsertAfter(assignment, PostIncrDecr(assignment.target, "--", assignment.position), parent)
-                            )
-                        }
-                        rightnum == 2.0 -> {
-                            // x += y - 2  -> x += y ,  x--,  x--
-                            return listOf(
-                                    IAstModification.ReplaceNode(assignment.value, binExpr.left, assignment),
-                                    IAstModification.InsertAfter(assignment, PostIncrDecr(assignment.target, "--", assignment.position), parent),
-                                    IAstModification.InsertAfter(assignment, PostIncrDecr(assignment.target, "--", assignment.position), parent)
-                            )
-                        }
-                    }
-                }
-            }
-        } else if(assignment.aug_op == "-=") {
-            val binExpr = assignment.value as? BinaryExpression
-            if (binExpr != null) {
-                val leftnum = binExpr.left.constValue(program)?.number?.toDouble()
-                val rightnum = binExpr.right.constValue(program)?.number?.toDouble()
-                if(binExpr.operator == "+") {
-                    when {
-                        leftnum == 1.0 -> {
-                            optimizationsDone++
-                            return listOf(IAstModification.SwapOperands(binExpr))
-                        }
-                        leftnum == 2.0 -> {
-                            optimizationsDone++
-                            return listOf(IAstModification.SwapOperands(binExpr))
-                        }
-                        rightnum == 1.0 -> {
-                            // x -= y + 1  -> x -= y ,  x--
-                            return listOf(
-                                    IAstModification.ReplaceNode(assignment.value, binExpr.left, assignment),
-                                    IAstModification.InsertAfter(assignment, PostIncrDecr(assignment.target, "--", assignment.position), parent)
-                            )
-                        }
-                        rightnum == 2.0 -> {
-                            // x -= y + 2  -> x -= y ,  x--,  x--
-                            return listOf(
-                                    IAstModification.ReplaceNode(assignment.value, binExpr.left, assignment),
-                                    IAstModification.InsertAfter(assignment, PostIncrDecr(assignment.target, "--", assignment.position), parent),
-                                    IAstModification.InsertAfter(assignment, PostIncrDecr(assignment.target, "--", assignment.position), parent)
-                            )
-                        }
-                    }
-                } else if(binExpr.operator == "-") {
-                    when {
-                        leftnum == 1.0 -> {
-                            optimizationsDone++
-                            return listOf(IAstModification.SwapOperands(binExpr))
-                        }
-                        leftnum == 2.0 -> {
-                            optimizationsDone++
-                            return listOf(IAstModification.SwapOperands(binExpr))
-                        }
-                        rightnum == 1.0 -> {
-                            // x -= y - 1  -> x -= y ,  x++
-                            return listOf(
-                                    IAstModification.ReplaceNode(assignment.value, binExpr.left, assignment),
-                                    IAstModification.InsertAfter(assignment, PostIncrDecr(assignment.target, "++", assignment.position), parent)
-                            )
-                        }
-                        rightnum == 2.0 -> {
-                            // x -= y - 2  -> x -= y ,  x++,  x++
-                            return listOf(
-                                    IAstModification.ReplaceNode(assignment.value, binExpr.left, assignment),
-                                    IAstModification.InsertAfter(assignment, PostIncrDecr(assignment.target, "++", assignment.position), parent),
-                                    IAstModification.InsertAfter(assignment, PostIncrDecr(assignment.target, "++", assignment.position), parent)
-                            )
-                        }
-                    }
-                }
-            }
-        }
-        return noModifications
-    }
-}

compiler/src/prog8/optimizer/CallGraph.kt

@@ -24,10 +24,10 @@ private val asmRefRx = Regex("""[\-+a-zA-Z0-9_ \t]+(...)[ \t]+(\S+).*""", RegexO
 
 class CallGraph(private val program: Program) : IAstVisitor {
 
-    val modulesImporting = mutableMapOf<Module, List<Module>>().withDefault { mutableListOf() }
-    val modulesImportedBy = mutableMapOf<Module, List<Module>>().withDefault { mutableListOf() }
-    val subroutinesCalling = mutableMapOf<INameScope, List<Subroutine>>().withDefault { mutableListOf() }
-    val subroutinesCalledBy = mutableMapOf<Subroutine, List<Node>>().withDefault { mutableListOf() }
+    val imports = mutableMapOf<Module, List<Module>>().withDefault { mutableListOf() }
+    val importedBy = mutableMapOf<Module, List<Module>>().withDefault { mutableListOf() }
+    val calls = mutableMapOf<INameScope, 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>()
@@ -55,17 +55,8 @@ class CallGraph(private val program: Program) : IAstVisitor {
             it.importedBy.clear()
             it.imports.clear()
 
-            it.importedBy.addAll(modulesImportedBy.getValue(it))
-            it.imports.addAll(modulesImporting.getValue(it))
-
-            forAllSubroutines(it) { sub ->
-                sub.calledBy.clear()
-                sub.calls.clear()
-
-                sub.calledBy.addAll(subroutinesCalledBy.getValue(sub))
-                sub.calls.addAll(subroutinesCalling.getValue(sub))
-            }
-
+            it.importedBy.addAll(importedBy.getValue(it))
+            it.imports.addAll(imports.getValue(it))
         }
 
         val rootmodule = program.modules.first()
@@ -85,8 +76,8 @@ class CallGraph(private val program: Program) : IAstVisitor {
         val thisModule = directive.definingModule()
         if (directive.directive == "%import") {
             val importedModule: Module = program.modules.single { it.name == directive.args[0].name }
-            modulesImporting[thisModule] = modulesImporting.getValue(thisModule).plus(importedModule)
-            modulesImportedBy[importedModule] = modulesImportedBy.getValue(importedModule).plus(thisModule)
+            imports[thisModule] = imports.getValue(thisModule).plus(importedModule)
+            importedBy[importedModule] = importedBy.getValue(importedModule).plus(thisModule)
         } else if (directive.directive == "%asminclude") {
             val asm = loadAsmIncludeFile(directive.args[0].str!!, thisModule.source)
             val scope = directive.definingScope()
@@ -141,8 +132,8 @@ class CallGraph(private val program: Program) : IAstVisitor {
         val otherSub = functionCall.target.targetSubroutine(program.namespace)
         if (otherSub != null) {
             functionCall.definingSubroutine()?.let { thisSub ->
-                subroutinesCalling[thisSub] = subroutinesCalling.getValue(thisSub).plus(otherSub)
-                subroutinesCalledBy[otherSub] = subroutinesCalledBy.getValue(otherSub).plus(functionCall)
+                calls[thisSub] = calls.getValue(thisSub).plus(otherSub)
+                calledBy[otherSub] = calledBy.getValue(otherSub).plus(functionCall)
             }
         }
         super.visit(functionCall)
@@ -152,8 +143,8 @@ class CallGraph(private val program: Program) : IAstVisitor {
         val otherSub = functionCallStatement.target.targetSubroutine(program.namespace)
         if (otherSub != null) {
             functionCallStatement.definingSubroutine()?.let { thisSub ->
-                subroutinesCalling[thisSub] = subroutinesCalling.getValue(thisSub).plus(otherSub)
-                subroutinesCalledBy[otherSub] = subroutinesCalledBy.getValue(otherSub).plus(functionCallStatement)
+                calls[thisSub] = calls.getValue(thisSub).plus(otherSub)
+                calledBy[otherSub] = calledBy.getValue(otherSub).plus(functionCallStatement)
             }
         }
         super.visit(functionCallStatement)
@@ -163,8 +154,8 @@ class CallGraph(private val program: Program) : IAstVisitor {
         val otherSub = jump.identifier?.targetSubroutine(program.namespace)
         if (otherSub != null) {
             jump.definingSubroutine()?.let { thisSub ->
-                subroutinesCalling[thisSub] = subroutinesCalling.getValue(thisSub).plus(otherSub)
-                subroutinesCalledBy[otherSub] = subroutinesCalledBy.getValue(otherSub).plus(jump)
+                calls[thisSub] = calls.getValue(thisSub).plus(otherSub)
+                calledBy[otherSub] = calledBy.getValue(otherSub).plus(jump)
             }
         }
         super.visit(jump)
@@ -190,14 +181,14 @@ class CallGraph(private val program: Program) : IAstVisitor {
                 if (jumptarget != null && (jumptarget[0].isLetter() || jumptarget[0] == '_')) {
                     val node = program.namespace.lookup(jumptarget.split('.'), context)
                     if (node is Subroutine) {
-                        subroutinesCalling[scope] = subroutinesCalling.getValue(scope).plus(node)
-                        subroutinesCalledBy[node] = subroutinesCalledBy.getValue(node).plus(context)
+                        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) {
-                            subroutinesCalling[scope] = subroutinesCalling.getValue(scope).plus(node2)
-                            subroutinesCalledBy[node2] = subroutinesCalledBy.getValue(node2).plus(context)
+                            calls[scope] = calls.getValue(scope).plus(node2)
+                            calledBy[node2] = calledBy.getValue(node2).plus(context)
                         }
                     }
                 }
@@ -209,8 +200,8 @@ class CallGraph(private val program: Program) : IAstVisitor {
                         if (target.contains('.')) {
                             val node = program.namespace.lookup(listOf(target.substringBefore('.')), context)
                             if (node is Subroutine) {
-                                subroutinesCalling[scope] = subroutinesCalling.getValue(scope).plus(node)
-                                subroutinesCalledBy[node] = subroutinesCalledBy.getValue(node).plus(context)
+                                calls[scope] = calls.getValue(scope).plus(node)
+                                calledBy[node] = calledBy.getValue(node).plus(context)
                             }
                         }
                     }

compiler/src/prog8/optimizer/ConstExprEvaluator.kt

@@ -132,11 +132,11 @@ class ConstExprEvaluator {
     private fun bitwiseand(left: NumericLiteralValue, right: NumericLiteralValue): NumericLiteralValue {
         if(left.type== DataType.UBYTE) {
             if(right.type in IntegerDatatypes) {
-                return NumericLiteralValue(DataType.UBYTE, (left.number.toInt() or (right.number.toInt() and 255)).toShort(), left.position)
+                return NumericLiteralValue(DataType.UBYTE, (left.number.toInt() and (right.number.toInt() and 255)).toShort(), left.position)
             }
         } else if(left.type== DataType.UWORD) {
             if(right.type in IntegerDatatypes) {
-                return NumericLiteralValue(DataType.UWORD, left.number.toInt() or right.number.toInt(), left.position)
+                return NumericLiteralValue(DataType.UWORD, left.number.toInt() and right.number.toInt(), left.position)
             }
         }
         throw ExpressionError("cannot calculate $left & $right", left.position)
@@ -163,7 +163,7 @@ class ConstExprEvaluator {
         val error = "cannot add $left and $right"
         return when (left.type) {
             in IntegerDatatypes -> when (right.type) {
-                in IntegerDatatypes -> NumericLiteralValue.optimalNumeric(left.number.toInt() + right.number.toInt(), left.position)
+                in IntegerDatatypes -> NumericLiteralValue.optimalInteger(left.number.toInt() + right.number.toInt(), left.position)
                 DataType.FLOAT -> NumericLiteralValue(DataType.FLOAT, left.number.toInt() + right.number.toDouble(), left.position)
                 else -> throw ExpressionError(error, left.position)
             }
@@ -180,7 +180,7 @@ class ConstExprEvaluator {
         val error = "cannot subtract $left and $right"
         return when (left.type) {
             in IntegerDatatypes -> when (right.type) {
-                in IntegerDatatypes -> NumericLiteralValue.optimalNumeric(left.number.toInt() - right.number.toInt(), left.position)
+                in IntegerDatatypes -> NumericLiteralValue.optimalInteger(left.number.toInt() - right.number.toInt(), left.position)
                 DataType.FLOAT -> NumericLiteralValue(DataType.FLOAT, left.number.toInt() - right.number.toDouble(), left.position)
                 else -> throw ExpressionError(error, left.position)
             }
@@ -197,7 +197,7 @@ class ConstExprEvaluator {
         val error = "cannot multiply ${left.type} and ${right.type}"
         return when (left.type) {
             in IntegerDatatypes -> when (right.type) {
-                in IntegerDatatypes -> NumericLiteralValue.optimalNumeric(left.number.toInt() * right.number.toInt(), left.position)
+                in IntegerDatatypes -> NumericLiteralValue.optimalInteger(left.number.toInt() * right.number.toInt(), left.position)
                 DataType.FLOAT -> NumericLiteralValue(DataType.FLOAT, left.number.toInt() * right.number.toDouble(), left.position)
                 else -> throw ExpressionError(error, left.position)
             }
@@ -220,7 +220,7 @@ class ConstExprEvaluator {
                 in IntegerDatatypes -> {
                     if(right.number.toInt()==0) divideByZeroError(right.position)
                     val result: Int = left.number.toInt() / right.number.toInt()
-                    NumericLiteralValue.optimalNumeric(result, left.position)
+                    NumericLiteralValue.optimalInteger(result, left.position)
                 }
                 DataType.FLOAT -> {
                     if(right.number.toDouble()==0.0) divideByZeroError(right.position)

compiler/src/prog8/optimizer/ConstantFoldingOptimizer.kt

@@ -171,7 +171,7 @@ internal class ConstantIdentifierReplacer(private val program: Program, private
         if(declValue!=null && decl.type==VarDeclType.VAR
                 && declValue is NumericLiteralValue && !declValue.inferType(program).istype(decl.datatype)) {
             // cast the numeric literal to the appropriate datatype of the variable
-            return listOf(IAstModification.ReplaceNode(decl.value!!, declValue.cast(decl.datatype), decl))
+            return listOf(IAstModification.ReplaceNode(decl.value!!, declValue.castNoCheck(decl.datatype), decl))
         }
 
         return noModifications
@@ -179,7 +179,7 @@ internal class ConstantIdentifierReplacer(private val program: Program, private
 }
 
 
-internal class ConstantFoldingOptimizer(private val program: Program, private val errors: ErrorReporter) : AstWalker() {
+internal class ConstantFoldingOptimizer(private val program: Program) : AstWalker() {
     private val noModifications = emptyList<IAstModification>()
 
     override fun before(memread: DirectMemoryRead, parent: Node): Iterable<IAstModification> {
@@ -203,7 +203,7 @@ internal class ConstantFoldingOptimizer(private val program: Program, private va
                 "-" -> when (subexpr.type) {
                     in IntegerDatatypes -> {
                         listOf(IAstModification.ReplaceNode(expr,
-                                NumericLiteralValue.optimalNumeric(-subexpr.number.toInt(), subexpr.position),
+                                NumericLiteralValue.optimalInteger(-subexpr.number.toInt(), subexpr.position),
                                 parent))
                     }
                     DataType.FLOAT -> {
@@ -216,7 +216,7 @@ internal class ConstantFoldingOptimizer(private val program: Program, private va
                 "~" -> when (subexpr.type) {
                     in IntegerDatatypes -> {
                         listOf(IAstModification.ReplaceNode(expr,
-                                NumericLiteralValue.optimalNumeric(subexpr.number.toInt().inv(), subexpr.position),
+                                NumericLiteralValue.optimalInteger(subexpr.number.toInt().inv(), subexpr.position),
                                 parent))
                     }
                     else -> throw ExpressionError("can only take bitwise inversion of int", subexpr.position)
@@ -273,11 +273,8 @@ internal class ConstantFoldingOptimizer(private val program: Program, private va
         // const fold when both operands are a const
         if(leftconst != null && rightconst != null) {
             val evaluator = ConstExprEvaluator()
-            return listOf(IAstModification.ReplaceNode(
-                    expr,
-                    evaluator.evaluate(leftconst, expr.operator, rightconst),
-                    parent
-            ))
+            val result = evaluator.evaluate(leftconst, expr.operator, rightconst)
+            return listOf(IAstModification.ReplaceNode(expr, result, parent))
         }
 
         return noModifications
@@ -323,13 +320,13 @@ internal class ConstantFoldingOptimizer(private val program: Program, private va
             val newFrom: NumericLiteralValue
             val newTo: NumericLiteralValue
             try {
-                newFrom = rangeFrom.cast(targetDt)
-                newTo = rangeTo.cast(targetDt)
+                newFrom = rangeFrom.castNoCheck(targetDt)
+                newTo = rangeTo.castNoCheck(targetDt)
             } catch (x: ExpressionError) {
                 return range
             }
             val newStep: Expression = try {
-                stepLiteral?.cast(targetDt)?: range.step
+                stepLiteral?.castNoCheck(targetDt)?: range.step
             } catch(ee: ExpressionError) {
                 range.step
             }
@@ -342,45 +339,55 @@ internal class ConstantFoldingOptimizer(private val program: Program, private va
         val rangeTo = iterableRange.to as? NumericLiteralValue
         if(rangeFrom==null || rangeTo==null) return noModifications
 
-        val loopvar = forLoop.loopVar?.targetVarDecl(program.namespace)
-        if(loopvar!=null) {
-            val stepLiteral = iterableRange.step as? NumericLiteralValue
-            when(loopvar.datatype) {
-                DataType.UBYTE -> {
-                    if(rangeFrom.type!= DataType.UBYTE) {
-                        // attempt to translate the iterable into ubyte values
-                        val newIter = adjustRangeDt(rangeFrom, loopvar.datatype, rangeTo, stepLiteral, iterableRange)
-                        return listOf(IAstModification.ReplaceNode(forLoop.iterable, newIter, forLoop))
-                    }
+        val loopvar = forLoop.loopVar.targetVarDecl(program.namespace)!!
+        val stepLiteral = iterableRange.step as? NumericLiteralValue
+        when(loopvar.datatype) {
+            DataType.UBYTE -> {
+                if(rangeFrom.type!= DataType.UBYTE) {
+                    // attempt to translate the iterable into ubyte values
+                    val newIter = adjustRangeDt(rangeFrom, loopvar.datatype, rangeTo, stepLiteral, iterableRange)
+                    return listOf(IAstModification.ReplaceNode(forLoop.iterable, newIter, forLoop))
                 }
-                DataType.BYTE -> {
-                    if(rangeFrom.type!= DataType.BYTE) {
-                        // attempt to translate the iterable into byte values
-                        val newIter = adjustRangeDt(rangeFrom, loopvar.datatype, rangeTo, stepLiteral, iterableRange)
-                        return listOf(IAstModification.ReplaceNode(forLoop.iterable, newIter, forLoop))
-                    }
-                }
-                DataType.UWORD -> {
-                    if(rangeFrom.type!= DataType.UWORD) {
-                        // attempt to translate the iterable into uword values
-                        val newIter = adjustRangeDt(rangeFrom, loopvar.datatype, rangeTo, stepLiteral, iterableRange)
-                        return listOf(IAstModification.ReplaceNode(forLoop.iterable, newIter, forLoop))
-                    }
-                }
-                DataType.WORD -> {
-                    if(rangeFrom.type!= DataType.WORD) {
-                        // attempt to translate the iterable into word values
-                        val newIter = adjustRangeDt(rangeFrom, loopvar.datatype, rangeTo, stepLiteral, iterableRange)
-                        return listOf(IAstModification.ReplaceNode(forLoop.iterable, newIter, forLoop))
-                    }
-                }
-                else -> throw FatalAstException("invalid loopvar datatype $loopvar")
             }
+            DataType.BYTE -> {
+                if(rangeFrom.type!= DataType.BYTE) {
+                    // attempt to translate the iterable into byte values
+                    val newIter = adjustRangeDt(rangeFrom, loopvar.datatype, rangeTo, stepLiteral, iterableRange)
+                    return listOf(IAstModification.ReplaceNode(forLoop.iterable, newIter, forLoop))
+                }
+            }
+            DataType.UWORD -> {
+                if(rangeFrom.type!= DataType.UWORD) {
+                    // attempt to translate the iterable into uword values
+                    val newIter = adjustRangeDt(rangeFrom, loopvar.datatype, rangeTo, stepLiteral, iterableRange)
+                    return listOf(IAstModification.ReplaceNode(forLoop.iterable, newIter, forLoop))
+                }
+            }
+            DataType.WORD -> {
+                if(rangeFrom.type!= DataType.WORD) {
+                    // attempt to translate the iterable into word values
+                    val newIter = adjustRangeDt(rangeFrom, loopvar.datatype, rangeTo, stepLiteral, iterableRange)
+                    return listOf(IAstModification.ReplaceNode(forLoop.iterable, newIter, forLoop))
+                }
+            }
+            else -> throw FatalAstException("invalid loopvar datatype $loopvar")
         }
 
         return noModifications
     }
 
+    override fun after(decl: VarDecl, parent: Node): Iterable<IAstModification> {
+        val numval = decl.value as? NumericLiteralValue
+        if(decl.type== VarDeclType.CONST && numval!=null) {
+            val valueDt = numval.inferType(program)
+            if(!valueDt.istype(decl.datatype)) {
+                val adjustedVal = numval.castNoCheck(decl.datatype)
+                return listOf(IAstModification.ReplaceNode(numval, adjustedVal, decl))
+            }
+        }
+        return noModifications
+    }
+
     private class ShuffleOperands(val expr: BinaryExpression,
                                   val exprOperator: String?,
                                   val subExpr: BinaryExpression,

compiler/src/prog8/optimizer/ExpressionSimplifier.kt

@@ -6,7 +6,6 @@ import prog8.ast.base.*
 import prog8.ast.expressions.*
 import prog8.ast.processing.AstWalker
 import prog8.ast.processing.IAstModification
-import prog8.ast.statements.Assignment
 import kotlin.math.abs
 import kotlin.math.log2
 import kotlin.math.pow
@@ -24,32 +23,29 @@ internal class ExpressionSimplifier(private val program: Program) : AstWalker()
     private val negativePowersOfTwo = powersOfTwo.map { -it }.toSet()
     private val noModifications = emptyList<IAstModification>()
 
-    override fun after(assignment: Assignment, parent: Node): Iterable<IAstModification> {
-        if (assignment.aug_op != null)
-            throw FatalAstException("augmented assignments should have been converted to normal assignments before this optimizer: $assignment")
-        return noModifications
-    }
-
     override fun after(typecast: TypecastExpression, parent: Node): Iterable<IAstModification> {
         val mods = mutableListOf<IAstModification>()
 
         // try to statically convert a literal value into one of the desired type
         val literal = typecast.expression as? NumericLiteralValue
         if (literal != null) {
-            val newLiteral = literal.cast(typecast.type)
+            val newLiteral = literal.castNoCheck(typecast.type)
             if (newLiteral !== literal)
                 mods += IAstModification.ReplaceNode(typecast.expression, newLiteral, typecast)
         }
 
-        // remove redundant nested typecasts:
-        // if the typecast casts a value to the same type, remove the cast.
-        // if the typecast contains another typecast, remove the inner typecast.
+        // remove redundant nested typecasts
         val subTypecast = typecast.expression as? TypecastExpression
         if (subTypecast != null) {
-            mods += IAstModification.ReplaceNode(typecast.expression, subTypecast.expression, typecast)
+            // remove the sub-typecast if its datatype is larger than the outer typecast
+            if(subTypecast.type largerThan typecast.type) {
+                mods += IAstModification.ReplaceNode(typecast.expression, subTypecast.expression, typecast)
+            }
         } else {
-            if (typecast.expression.inferType(program).istype(typecast.type))
+            if (typecast.expression.inferType(program).istype(typecast.type)) {
+                // remove duplicate cast
                 mods += IAstModification.ReplaceNode(typecast, typecast.expression, parent)
+            }
         }
 
         return mods
@@ -610,8 +606,7 @@ internal class ExpressionSimplifier(private val program: Program) : AstWalker()
         if (amount == 0) {
             return expr.left
         }
-        val targetDt = expr.left.inferType(program).typeOrElse(DataType.STRUCT)
-        when (targetDt) {
+        when (expr.left.inferType(program).typeOrElse(DataType.STRUCT)) {
             DataType.UBYTE -> {
                 if (amount >= 8) {
                     return NumericLiteralValue.optimalInteger(0, expr.position)

compiler/src/prog8/optimizer/Extensions.kt

@@ -10,7 +10,7 @@ internal fun Program.constantFold(errors: ErrorReporter) {
     if(errors.isEmpty()) {
         replacer.applyModifications()
 
-        val optimizer = ConstantFoldingOptimizer(this, errors)
+        val optimizer = ConstantFoldingOptimizer(this)
         optimizer.visit(this)
         while (errors.isEmpty() && optimizer.applyModifications() > 0) {
             optimizer.visit(this)

compiler/src/prog8/optimizer/FlattenAnonymousScopesAndNopRemover.kt

@@ -1,46 +0,0 @@
-package prog8.optimizer
-
-import prog8.ast.INameScope
-import prog8.ast.Node
-import prog8.ast.Program
-import prog8.ast.processing.IAstVisitor
-import prog8.ast.statements.AnonymousScope
-import prog8.ast.statements.NopStatement
-import prog8.ast.statements.Statement
-
-internal class FlattenAnonymousScopesAndNopRemover: IAstVisitor {
-    private var scopesToFlatten = mutableListOf<INameScope>()
-    private val nopStatements = mutableListOf<NopStatement>()
-
-    override fun visit(program: Program) {
-        super.visit(program)
-        for(scope in scopesToFlatten.reversed()) {
-            val namescope = scope.parent as INameScope
-            val idx = namescope.statements.indexOf(scope as Statement)
-            if(idx>=0) {
-                val nop = NopStatement.insteadOf(namescope.statements[idx])
-                nop.parent = namescope as Node
-                namescope.statements[idx] = nop
-                namescope.statements.addAll(idx, scope.statements)
-                scope.statements.forEach { it.parent = namescope }
-                visit(nop)
-            }
-        }
-
-        this.nopStatements.forEach {
-            it.definingScope().remove(it)
-        }
-    }
-
-    override fun visit(scope: AnonymousScope) {
-        if(scope.parent is INameScope) {
-            scopesToFlatten.add(scope)  // get rid of the anonymous scope
-        }
-
-        return super.visit(scope)
-    }
-
-    override fun visit(nopStatement: NopStatement) {
-        nopStatements.add(nopStatement)
-    }
-}

compiler/src/prog8/optimizer/StatementOptimizer.kt

@@ -14,12 +14,6 @@ import prog8.functions.BuiltinFunctions
 import kotlin.math.floor
 
 
-/*
-    TODO: remove unreachable code after return and exit()
-    TODO: proper inlining of tiny subroutines (at first, restrict to subs without parameters and variables in them, and build it up from there: correctly renaming/relocating all variables in them and refs to those as well)
-*/
-
-
 internal class StatementOptimizer(private val program: Program,
                                   private val errors: ErrorReporter) : AstWalker() {
 
@@ -47,7 +41,11 @@ internal class StatementOptimizer(private val program: Program,
         if(subroutine.asmAddress==null && !forceOutput) {
             if(subroutine.containsNoCodeNorVars()) {
                 errors.warn("removing empty subroutine '${subroutine.name}'", subroutine.position)
-                return listOf(IAstModification.Remove(subroutine, parent))
+                val removals = callgraph.calledBy.getValue(subroutine).map {
+                    IAstModification.Remove(it, it.parent)
+                }.toMutableList()
+                removals += IAstModification.Remove(subroutine, parent)
+                return removals
             }
         }
 
@@ -102,32 +100,34 @@ internal class StatementOptimizer(private val program: Program,
             }
             if(stringVar!=null) {
                 val vardecl = stringVar.targetVarDecl(program.namespace)!!
-                val string = vardecl.value!! as StringLiteralValue
-                val pos = functionCallStatement.position
-                if(string.value.length==1) {
-                    val firstCharEncoded = CompilationTarget.encodeString(string.value, string.altEncoding)[0]
-                    val chrout = FunctionCallStatement(
-                            IdentifierReference(listOf("c64", "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 = CompilationTarget.encodeString(string.value.take(2), string.altEncoding)
-                    val chrout1 = FunctionCallStatement(
-                            IdentifierReference(listOf("c64", "CHROUT"), pos),
-                            mutableListOf(NumericLiteralValue(DataType.UBYTE, firstTwoCharsEncoded[0].toInt(), pos)),
-                            functionCallStatement.void, pos
-                    )
-                    val chrout2 = FunctionCallStatement(
-                            IdentifierReference(listOf("c64", "CHROUT"), pos),
-                            mutableListOf(NumericLiteralValue(DataType.UBYTE, firstTwoCharsEncoded[1].toInt(), pos)),
-                            functionCallStatement.void, pos
-                    )
-                    val anonscope = AnonymousScope(mutableListOf(), pos)
-                    anonscope.statements.add(chrout1)
-                    anonscope.statements.add(chrout2)
-                    return listOf(IAstModification.ReplaceNode(functionCallStatement, anonscope, parent))
+                val string = vardecl.value as? StringLiteralValue
+                if(string!=null) {
+                    val pos = functionCallStatement.position
+                    if (string.value.length == 1) {
+                        val firstCharEncoded = CompilationTarget.encodeString(string.value, string.altEncoding)[0]
+                        val chrout = FunctionCallStatement(
+                                IdentifierReference(listOf("c64", "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 = CompilationTarget.encodeString(string.value.take(2), string.altEncoding)
+                        val chrout1 = FunctionCallStatement(
+                                IdentifierReference(listOf("c64", "CHROUT"), pos),
+                                mutableListOf(NumericLiteralValue(DataType.UBYTE, firstTwoCharsEncoded[0].toInt(), pos)),
+                                functionCallStatement.void, pos
+                        )
+                        val chrout2 = FunctionCallStatement(
+                                IdentifierReference(listOf("c64", "CHROUT"), pos),
+                                mutableListOf(NumericLiteralValue(DataType.UBYTE, firstTwoCharsEncoded[1].toInt(), pos)),
+                                functionCallStatement.void, pos
+                        )
+                        val anonscope = AnonymousScope(mutableListOf(), pos)
+                        anonscope.statements.add(chrout1)
+                        anonscope.statements.add(chrout2)
+                        return listOf(IAstModification.ReplaceNode(functionCallStatement, anonscope, parent))
+                    }
                 }
             }
         }
@@ -136,7 +136,7 @@ internal class StatementOptimizer(private val program: Program,
         val subroutine = functionCallStatement.target.targetSubroutine(program.namespace)
         if(subroutine!=null) {
             val first = subroutine.statements.asSequence().filterNot { it is VarDecl || it is Directive }.firstOrNull()
-            if(first is ReturnFromIrq || first is Return)
+            if(first is Return)
                 return listOf(IAstModification.Remove(functionCallStatement, parent))
         }
 
@@ -192,11 +192,11 @@ internal class StatementOptimizer(private val program: Program,
 
     override fun after(forLoop: ForLoop, parent: Node): Iterable<IAstModification> {
         if(forLoop.body.containsNoCodeNorVars()) {
-            // remove empty for loop
+            errors.warn("removing empty for loop", forLoop.position)
             return listOf(IAstModification.Remove(forLoop, parent))
         } else if(forLoop.body.statements.size==1) {
             val loopvar = forLoop.body.statements[0] as? VarDecl
-            if(loopvar!=null && loopvar.name==forLoop.loopVar?.nameInSource?.singleOrNull()) {
+            if(loopvar!=null && loopvar.name==forLoop.loopVar.nameInSource.singleOrNull()) {
                 // remove empty for loop (only loopvar decl in it)
                 return listOf(IAstModification.Remove(forLoop, parent))
             }
@@ -208,7 +208,7 @@ internal class StatementOptimizer(private val program: Program,
                 // for loop over a (constant) range of just a single value-- optimize the loop away
                 // loopvar/reg = range value , follow by block
                 val scope = AnonymousScope(mutableListOf(), forLoop.position)
-                scope.statements.add(Assignment(AssignTarget(forLoop.loopRegister, forLoop.loopVar, null, null, forLoop.position), null, range.from, forLoop.position))
+                scope.statements.add(Assignment(AssignTarget(forLoop.loopVar, null, null, forLoop.position), range.from, forLoop.position))
                 scope.statements.addAll(forLoop.body.statements)
                 return listOf(IAstModification.ReplaceNode(forLoop, scope, parent))
             }
@@ -223,7 +223,7 @@ internal class StatementOptimizer(private val program: Program,
                     val character = CompilationTarget.encodeString(sv.value, sv.altEncoding)[0]
                     val byte = NumericLiteralValue(DataType.UBYTE, character, iterable.position)
                     val scope = AnonymousScope(mutableListOf(), forLoop.position)
-                    scope.statements.add(Assignment(AssignTarget(forLoop.loopRegister, forLoop.loopVar, null, null, forLoop.position), null, byte, forLoop.position))
+                    scope.statements.add(Assignment(AssignTarget(forLoop.loopVar, null, null, forLoop.position), byte, forLoop.position))
                     scope.statements.addAll(forLoop.body.statements)
                     return listOf(IAstModification.ReplaceNode(forLoop, scope, parent))
                 }
@@ -236,7 +236,7 @@ internal class StatementOptimizer(private val program: Program,
                     if(av!=null) {
                         val scope = AnonymousScope(mutableListOf(), forLoop.position)
                         scope.statements.add(Assignment(
-                                AssignTarget(forLoop.loopRegister, forLoop.loopVar, null, null, forLoop.position), null, NumericLiteralValue.optimalInteger(av.toInt(), iterable.position),
+                                AssignTarget(forLoop.loopVar, null, null, forLoop.position), NumericLiteralValue.optimalInteger(av.toInt(), iterable.position),
                                 forLoop.position))
                         scope.statements.addAll(forLoop.body.statements)
                         return listOf(IAstModification.ReplaceNode(forLoop, scope, parent))
@@ -248,18 +248,18 @@ internal class StatementOptimizer(private val program: Program,
         return noModifications
     }
 
-    override fun before(repeatLoop: RepeatLoop, parent: Node): Iterable<IAstModification> {
-        val constvalue = repeatLoop.untilCondition.constValue(program)
+    override fun before(untilLoop: UntilLoop, parent: Node): Iterable<IAstModification> {
+        val constvalue = untilLoop.untilCondition.constValue(program)
         if(constvalue!=null) {
             if(constvalue.asBooleanValue) {
-                // always true -> keep only the statement block (if there are no continue and break statements)
-                errors.warn("condition is always true", repeatLoop.untilCondition.position)
-                if(!hasContinueOrBreak(repeatLoop.body))
-                    return listOf(IAstModification.ReplaceNode(repeatLoop, repeatLoop.body, parent))
+                // always true -> keep only the statement block (if there are no break statements)
+                errors.warn("condition is always true", untilLoop.untilCondition.position)
+                if(!hasBreak(untilLoop.body))
+                    return listOf(IAstModification.ReplaceNode(untilLoop, untilLoop.body, parent))
             } else {
                 // always false
-                val forever = ForeverLoop(repeatLoop.body, repeatLoop.position)
-                return listOf(IAstModification.ReplaceNode(repeatLoop, forever, parent))
+                val forever = RepeatLoop(null, untilLoop.body, untilLoop.position)
+                return listOf(IAstModification.ReplaceNode(untilLoop, forever, parent))
             }
         }
         return noModifications
@@ -270,7 +270,7 @@ internal class StatementOptimizer(private val program: Program,
         if(constvalue!=null) {
             return if(constvalue.asBooleanValue) {
                 // always true
-                val forever = ForeverLoop(whileLoop.body, whileLoop.position)
+                val forever = RepeatLoop(null, whileLoop.body, whileLoop.position)
                 listOf(IAstModification.ReplaceNode(whileLoop, forever, parent))
             } else {
                 // always false -> remove the while statement altogether
@@ -281,6 +281,26 @@ internal class StatementOptimizer(private val program: Program,
         return noModifications
     }
 
+    override fun after(repeatLoop: RepeatLoop, parent: Node): Iterable<IAstModification> {
+        val iter = repeatLoop.iterations
+        if(iter!=null) {
+            if(repeatLoop.body.containsNoCodeNorVars()) {
+                errors.warn("empty loop removed", repeatLoop.position)
+                return listOf(IAstModification.Remove(repeatLoop, parent))
+            }
+            val iterations = iter.constValue(program)?.number?.toInt()
+            if (iterations == 0) {
+                errors.warn("iterations is always 0, removed loop", iter.position)
+                return listOf(IAstModification.Remove(repeatLoop, parent))
+            }
+            if (iterations == 1) {
+                errors.warn("iterations is always 1", iter.position)
+                return listOf(IAstModification.ReplaceNode(repeatLoop, repeatLoop.body, parent))
+            }
+        }
+        return noModifications
+    }
+
     override fun after(whenStatement: WhenStatement, parent: Node): Iterable<IAstModification> {
         // remove empty choices
         class ChoiceRemover(val choice: WhenChoice) : IAstModification {
@@ -303,21 +323,74 @@ internal class StatementOptimizer(private val program: Program,
         return noModifications
     }
 
-    override fun after(assignment: Assignment, parent: Node): Iterable<IAstModification> {
-        if(assignment.aug_op!=null)
-            throw FatalAstException("augmented assignments should have been converted to normal assignments before this optimizer: $assignment")
+    override fun before(assignment: Assignment, parent: Node): Iterable<IAstModification> {
 
-        // remove assignments to self
+        val binExpr = assignment.value as? BinaryExpression
+        if(binExpr!=null) {
+            if(binExpr.left isSameAs assignment.target) {
+                val rExpr = binExpr.right as? BinaryExpression
+                if(rExpr!=null) {
+                    val op1 = binExpr.operator
+                    val op2 = rExpr.operator
+
+                    if(rExpr.left is NumericLiteralValue && op2 in setOf("+", "*", "&", "|")) {
+                        // associative operator, make sure the constant numeric value is second (right)
+                        return listOf(IAstModification.SwapOperands(rExpr))
+                    }
+
+                    val rNum = (rExpr.right as? NumericLiteralValue)?.number
+                    if(rNum!=null) {
+                        if (op1 == "+" || op1 == "-") {
+                            if (op2 == "+") {
+                                // A = A +/- B + N
+                                val expr2 = BinaryExpression(binExpr.left, binExpr.operator, rExpr.left, binExpr.position)
+                                val addConstant = Assignment(
+                                        assignment.target,
+                                        BinaryExpression(binExpr.left, "+", rExpr.right, rExpr.position),
+                                        assignment.position
+                                )
+                                return listOf(
+                                        IAstModification.ReplaceNode(binExpr, expr2, binExpr.parent),
+                                        IAstModification.InsertAfter(assignment, addConstant, parent))
+                            } else if (op2 == "-") {
+                                // A = A +/- B - N
+                                val expr2 = BinaryExpression(binExpr.left, binExpr.operator, rExpr.left, binExpr.position)
+                                val subConstant = Assignment(
+                                        assignment.target,
+                                        BinaryExpression(binExpr.left, "-", rExpr.right, rExpr.position),
+                                        assignment.position
+                                )
+                                return listOf(
+                                        IAstModification.ReplaceNode(binExpr, expr2, binExpr.parent),
+                                        IAstModification.InsertAfter(assignment, subConstant, parent))
+                            }
+                        }
+                    }
+                }
+            }
+
+            if(binExpr.operator in associativeOperators && binExpr.right isSameAs assignment.target) {
+                // associative operator, swap the operands so that the assignment target is first (left)
+                // unless the other operand is the same in which case we don't swap (endless loop!)
+                if (!(binExpr.left isSameAs binExpr.right))
+                    return listOf(IAstModification.SwapOperands(binExpr))
+            }
+
+        }
+
+        return noModifications
+    }
+
+    override fun after(assignment: Assignment, parent: Node): Iterable<IAstModification> {
         if(assignment.target isSameAs assignment.value) {
-            if(assignment.target.isNotMemory(program.namespace))
-                return listOf(IAstModification.Remove(assignment, parent))
+            // remove assignment to self
+            return listOf(IAstModification.Remove(assignment, parent))
         }
 
         val targetIDt = assignment.target.inferType(program, assignment)
         if(!targetIDt.isKnown)
             throw FatalAstException("can't infer type of assignment target")
 
-
         // optimize binary expressions a bit
         val targetDt = targetIDt.typeOrElse(DataType.STRUCT)
         val bexpr=assignment.value as? BinaryExpression
@@ -333,8 +406,8 @@ internal class StatementOptimizer(private val program: Program,
                         if (cv == 0.0) {
                             return listOf(IAstModification.Remove(assignment, parent))
                         } else if (targetDt in IntegerDatatypes && floor(cv) == cv) {
-                            if ((vardeclDt == VarDeclType.MEMORY && cv in 1.0..3.0) || (vardeclDt != VarDeclType.MEMORY && cv in 1.0..8.0)) {
-                                // replace by several INCs (a bit less when dealing with memory targets)
+                            if (vardeclDt != VarDeclType.MEMORY && cv 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(cv.toInt()) {
                                     incs.statements.add(PostIncrDecr(assignment.target, "++", assignment.position))
@@ -347,8 +420,8 @@ internal class StatementOptimizer(private val program: Program,
                         if (cv == 0.0) {
                             return listOf(IAstModification.Remove(assignment, parent))
                         } else if (targetDt in IntegerDatatypes && floor(cv) == cv) {
-                            if ((vardeclDt == VarDeclType.MEMORY && cv in 1.0..3.0) || (vardeclDt != VarDeclType.MEMORY && cv in 1.0..8.0)) {
-                                // replace by several DECs (a bit less when dealing with memory targets)
+                            if (vardeclDt != VarDeclType.MEMORY && cv 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(cv.toInt()) {
                                     decs.statements.add(PostIncrDecr(assignment.target, "--", assignment.position))
@@ -420,7 +493,7 @@ internal class StatementOptimizer(private val program: Program,
         return linesToRemove
     }
 
-    private fun hasContinueOrBreak(scope: INameScope): Boolean {
+    private fun hasBreak(scope: INameScope): Boolean {
 
         class Searcher: IAstVisitor
         {
@@ -429,10 +502,6 @@ internal class StatementOptimizer(private val program: Program,
             override fun visit(breakStmt: Break) {
                 count++
             }
-
-            override fun visit(contStmt: Continue) {
-                count++
-            }
         }
 
         val s=Searcher()

compiler/src/prog8/optimizer/UnusedCodeRemover.kt

@@ -1,13 +1,14 @@
 package prog8.optimizer
 
+import prog8.ast.INameScope
 import prog8.ast.Node
 import prog8.ast.Program
+import prog8.ast.base.ErrorReporter
 import prog8.ast.processing.AstWalker
 import prog8.ast.processing.IAstModification
-import prog8.ast.statements.Block
+import prog8.ast.statements.*
 
-
-internal class UnusedCodeRemover: AstWalker() {
+internal class UnusedCodeRemover(private val errors: ErrorReporter): AstWalker() {
 
     override fun before(program: Program, parent: Node): Iterable<IAstModification> {
         val callgraph = CallGraph(program)
@@ -17,8 +18,9 @@ internal class UnusedCodeRemover: AstWalker() {
         val entrypoint = program.entrypoint()
         program.modules.forEach {
             callgraph.forAllSubroutines(it) { sub ->
-                if (sub !== entrypoint && !sub.keepAlways && (sub.calledBy.isEmpty() || (sub.containsNoCodeNorVars() && !sub.isAsmSubroutine)))
+                if (sub !== entrypoint && !sub.isAsmSubroutine && (callgraph.calledBy[sub].isNullOrEmpty() || sub.containsNoCodeNorVars())) {
                     removals.add(IAstModification.Remove(sub, sub.definingScope() as Node))
+                }
             }
         }
 
@@ -35,4 +37,33 @@ internal class UnusedCodeRemover: AstWalker() {
 
         return removals
     }
+
+
+    override fun before(breakStmt: Break, parent: Node): Iterable<IAstModification> {
+        reportUnreachable(breakStmt, parent as INameScope)
+        return emptyList()
+    }
+
+    override fun before(jump: Jump, parent: Node): Iterable<IAstModification> {
+        reportUnreachable(jump, parent as INameScope)
+        return emptyList()
+    }
+
+    override fun before(returnStmt: Return, parent: Node): Iterable<IAstModification> {
+        reportUnreachable(returnStmt, parent as INameScope)
+        return emptyList()
+    }
+
+    override fun before(functionCallStatement: FunctionCallStatement, parent: Node): Iterable<IAstModification> {
+        if(functionCallStatement.target.nameInSource.last() == "exit")
+            reportUnreachable(functionCallStatement, parent as INameScope)
+        return emptyList()
+    }
+
+    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 -> {}
+            else -> errors.warn("unreachable code", next.position)
+        }
+    }
 }

compiler/src/prog8/parser/ModuleParsing.kt

@@ -34,7 +34,7 @@ internal class CustomLexer(val modulePath: Path, input: CharStream?) : prog8Lexe
 internal fun moduleName(fileName: Path) = fileName.toString().substringBeforeLast('.')
 
 
-internal class ModuleImporter(private val errors: ErrorReporter) {
+internal class ModuleImporter() {
 
     internal fun importModule(program: Program, filePath: Path): Module {
         print("importing '${moduleName(filePath.fileName)}'")

docs/source/index.rst

@@ -55,7 +55,7 @@ This code calculates prime numbers using the Sieve of Eratosthenes algorithm::
 
             c64scr.print("prime numbers up to 255:\n\n")
             ubyte amount=0
-            while true {
+            repeat {
                 ubyte prime = find_next_prime()
                 if prime==0
                     break
@@ -139,8 +139,8 @@ Design principles and features
 - 'One statement per line' code, resulting in clear readable programs.
 - Modular programming and scoping via modules, code blocks, and subroutines.
 - Provide high level programming constructs but at the same time stay close to the metal;
-  still able to directly use memory addresses, CPU registers and ROM subroutines,
-  and inline assembly to have full control when every cycle or byte matters
+  still able to directly use memory addresses and ROM subroutines,
+  and inline assembly to have full control when every register, cycle or byte matters
 - Arbitrary number of subroutine parameters
 - Complex nested expressions are possible
 - Nested subroutines can access variables from outer scopes to avoids the overhead to pass everything via parameters

docs/source/programming.rst

@@ -50,7 +50,7 @@ Code
     There are different kinds of instructions ('statements' is a better name) such as:
 
     - value assignment
-    - looping  (for, while, repeat, unconditional jumps)
+    - looping  (for, while, do-until, repeat, unconditional jumps)
     - conditional execution (if - then - else, when, and conditional jumps)
     - subroutine calls
     - label definition
@@ -137,7 +137,7 @@ Scopes are created using either of these two statements:
 
 .. important::
     Unlike most other programming languages, a new scope is *not* created inside
-    for, while and repeat statements, the if statement, and the branching conditionals.
+    for, while, repeat, and do-until statements, the if statement, and the branching conditionals.
     These all share the same scope from the subroutine they're defined in.
     You can define variables in these blocks, but these will be treated as if they
     were defined in the subroutine instead.
@@ -204,13 +204,6 @@ Example::
     byte  @zp  zeropageCounter = 42
 
 
-Variables that represent CPU hardware registers
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-
-The following variables are reserved
-and map directly (read/write) to a CPU hardware register: ``A``, ``X``, ``Y``.
-
-
 Integers
 ^^^^^^^^
 
@@ -264,6 +257,16 @@ Note that the various keywords for the data type and variable type (``byte``, ``
 can't be used as *identifiers* elsewhere. You can't make a variable, block or subroutine with the name ``byte``
 for instance.
 
+**Arrays at a specific memory location:**
+Using the memory-mapped syntax it is possible to define an array to be located at a specific memory location.
+For instance to reference the first 5 rows of the Commodore 64's screen matrix as an array, you can define::
+
+    &ubyte[5*40]  top5screenrows = $0400
+
+This way you can set the second character on the second row from the top like this::
+
+    top5screenrows[41] = '!'
+
 
 Strings
 ^^^^^^^
@@ -393,21 +396,21 @@ expected when the program is restarted.
 Loops
 -----
 
-The *for*-loop is used to let a variable (or register) iterate over a range of values. Iteration is done in steps of 1, but you can change this.
+The *for*-loop is used to let a variable iterate over a range of values. Iteration is done in steps of 1, but you can change this.
 The loop variable must be declared as byte or word earlier so you can reuse it for multiple occasions.
 Iterating with a floating point variable is not supported. If you want to loop over a floating-point array, use a loop with an integer index variable instead.
 
 The *while*-loop is used to repeat a piece of code while a certain condition is still true.
-The *repeat--until* loop is used to repeat a piece of code until a certain condition is true.
-
-The *forever*-loop is used to simply run a piece of code in a loop, forever. You can still
-break out of this loop if desired. A "while true" or "until false" loop is equivalent to
-a forever-loop.
+The *do--until* loop is used to repeat a piece of code until a certain condition is true.
+The *repeat* loop is used as a short notation of a for loop where the loop variable doesn't matter and you're only interested in the number of iterations.
+(without iteration count specified it simply loops forever).
 
 You can also create loops by using the ``goto`` statement, but this should usually be avoided.
 
+Breaking out of a loop prematurely is possible with the ``break`` statement.
+
 .. attention::
-    The value of the loop variable or register after executing the loop *is undefined*. Don't use it immediately
+    The value of the loop variable after executing the loop *is undefined*. Don't use it immediately
     after the loop without first assigning a new value to it!
     (this is an optimization issue to avoid having to deal with mostly useless post-loop logic to adjust the loop variable's value)
 
@@ -421,15 +424,15 @@ if statements
 Conditional execution means that the flow of execution changes based on certiain conditions,
 rather than having fixed gotos or subroutine calls::
 
-	if A>4 goto overflow
+	if aa>4 goto overflow
 
-	if X==3  Y = 4
-	if X==3  Y = 4 else  A = 2
+	if xx==3  yy = 4
+	if xx==3  yy = 4 else  aa = 2
 
-	if X==5 {
-		Y = 99
+	if xx==5 {
+		yy = 99
 	} else {
-		A = 3
+		aa = 3
 	}
 
 
@@ -493,16 +496,16 @@ Assignments
 -----------
 
 Assignment statements assign a single value to a target variable or memory location.
-Augmented assignments (such as ``A += X``) are also available, but these are just shorthands
-for normal assignments (``A = A + X``).
+Augmented assignments (such as ``aa += xx``) are also available, but these are just shorthands
+for normal assignments (``aa = aa + xx``).
 
-Only register variables and variables of type byte, word and float can be assigned a new value.
+Only variables of type byte, word and float can be assigned a new value.
 It's not possible to set a new value to string or array variables etc, because they get allocated
-a fixed amount of memory which will not change.
+a fixed amount of memory which will not change.  (You *can* change the value of elements in a string or array though).
 
 .. attention::
     **Data type conversion (in assignments):**
-    When assigning a value with a 'smaller' datatype to a register or variable with a 'larger' datatype,
+    When assigning a value with a 'smaller' datatype to variable with a 'larger' datatype,
     the value will be automatically converted to the target datatype:  byte --> word --> float.
     So assigning a byte to a word variable, or a word to a floating point variable, is fine.
     The reverse is *not* true: it is *not* possible to assign a value of a 'larger' datatype to
@@ -518,7 +521,7 @@ as the memory mapped address $d021.
 If you want to access a memory location directly (by using the address itself), without defining
 a memory mapped location, you can do so by enclosing the address in ``@(...)``::
 
-    A = @($d020)      ; set the A register to the current c64 screen border color ("peek(53280)")
+    color = @($d020)  ; set the variable 'color' to the current c64 screen border color ("peek(53280)")
     @($d020) = 0      ; set the c64 screen border to black ("poke 53280,0")
     @(vic+$20) = 6    ; you can also use expressions to 'calculate' the address
 
@@ -721,11 +724,17 @@ reverse(array)
 
 len(x)
     Number of values in the array value x, or the number of characters in a string (excluding the size or 0-byte).
-    Note: this can be different from the number of *bytes* in memory if the datatype isn't a byte.
+    Note: this can be different from the number of *bytes* in memory if the datatype isn't a byte. See sizeof().
     Note: lengths of strings and arrays are determined at compile-time! If your program modifies the actual
     length of the string during execution, the value of len(string) may no longer be correct!
     (use strlen function if you want to dynamically determine the length)
 
+sizeof(name)
+    Number of bytes that the object 'name' occupies in memory. This is a constant determined by the data type of
+    the object. For instance, for a variable of type uword, the sizeof is 2.
+    For an 10 element array of floats, it is 50 (on the C-64, where a float is 5 bytes).
+    Note: usually you will be interested in the number of elements in an array, use len() for that.
+
 strlen(str)
     Number of bytes in the string. This value is determined during runtime and counts upto
     the first terminating 0 byte in the string, regardless of the size of the string during compilation time.

docs/source/syntaxreference.rst

@@ -24,7 +24,7 @@ Everything after a semicolon ``;`` is a comment and is ignored.
 If the whole line is just a comment, it will be copied into the resulting assembly source code.
 This makes it easier to understand and relate the generated code. Examples::
 
-	A = 42    ; set the initial value to 42
+	counter = 42    ; set the initial value to 42
 	; next is the code that...
 
 
@@ -306,6 +306,7 @@ should be allocated by the compiler. Instead, the (mandatory) value assigned to
 should be the *memory address* where the value is located::
 
 	&byte BORDERCOLOR = $d020
+    &ubyte[5*40]  top5screenrows = $0400        ; works for array as well
 
 
 Direct access to memory locations
@@ -313,7 +314,7 @@ Direct access to memory locations
 Instead of defining a memory mapped name for a specific memory location, you can also
 directly access the memory. Enclose a numeric expression or literal with ``@(...)`` to do that::
 
-    A = @($d020)      ; set the A register to the current c64 screen border color ("peek(53280)")
+    color = @($d020)  ; set the variable 'color' to the current c64 screen border color ("peek(53280)")
     @($d020) = 0      ; set the c64 screen border to black ("poke 53280,0")
     @(vic+$20) = 6    ; a dynamic expression to 'calculate' the address
 
@@ -333,8 +334,6 @@ Reserved names
 
 The following names are reserved, they have a special meaning::
 
-	A     X    Y              ; 6502 hardware registers
-	Pc    Pz   Pn  Pv         ; 6502 status register flags
 	true  false              ; boolean values 1 and 0
 
 
@@ -406,10 +405,10 @@ assignment: ``=``
     Note that an assignment sometimes is not possible or supported.
 
 augmented assignment: ``+=``  ``-=``  ``*=``  ``/=``  ``**=``  ``&=``  ``|=``  ``^=``  ``<<=``  ``>>=``
-	Syntactic sugar; ``A += X`` is equivalent to ``A = A + X``
+	This is syntactic sugar; ``aa += xx`` is equivalent to ``aa = aa + xx``
 
 postfix increment and decrement: ``++``  ``--``
-	Syntactic sugar; ``A++`` is equivalent to ``A = A + 1``, and ``A--`` is equivalent to ``A = A - 1``.
+	Syntactic sugar; ``aa++`` is equivalent to ``aa = aa + 1``, and ``aa--`` is equivalent to ``aa = aa - 1``.
 	Because these operations are so common, we have these short forms.
 
 comparison: ``!=``  ``<``  ``>``  ``<=``  ``>=``
@@ -427,9 +426,9 @@ range creation:  ``to``
 
 		0 to 7		; range of values 0, 1, 2, 3, 4, 5, 6, 7  (constant)
 
-		A = 5
-		X = 10
-		A to X		; range of 5, 6, 7, 8, 9, 10
+		aa = 5
+		aa = 10
+	    aa to xx		; range of 5, 6, 7, 8, 9, 10
 
 		byte[] array = 10 to 13   ; sets the array to [1, 2, 3, 4]
 
@@ -551,7 +550,7 @@ Loops
 for loop
 ^^^^^^^^
 
-The loop variable must be a register or a byte/word variable,
+The loop variable must be a byte or word variable,
 and must be defined first in the local scope of the for loop.
 The expression that you loop over can be anything that supports iteration (such as ranges like ``0 to 100``,
 array variables and strings) *except* floating-point arrays (because a floating-point loop variable is not supported).
@@ -561,7 +560,6 @@ You can use a single statement, or a statement block like in the example below::
 	for <loopvar>  in  <expression>  [ step <amount> ]   {
 		; do something...
 		break		; break out of the loop
-		continue	; immediately enter next iteration
 	}
 
 For example, this is a for loop using a byte variable ``i``, defined before, to loop over a certain range of numbers::
@@ -594,35 +592,35 @@ You can use a single statement, or a statement block like in the example below::
 	while  <condition>  {
 		; do something...
 		break		; break out of the loop
-		continue	; immediately enter next iteration
 	}
 
 
-repeat-until loop
-^^^^^^^^^^^^^^^^^
+do-until loop
+^^^^^^^^^^^^^
 
 Until the given condition is true (1), repeat the given statement(s).
 You can use a single statement, or a statement block like in the example below::
 
-	repeat  {
+	do  {
 		; do something...
 		break		; break out of the loop
-		continue	; immediately enter next iteration
 	} until  <condition>
 
 
-forever loop
-^^^^^^^^^^^^
+repeat loop
+^^^^^^^^^^^
 
-Simply run the code in a loop, forever. It's the same as a while true or until false loop,
-or just a jump back to a previous label. You can still break out of this loop as well, if you want::
+When you're only interested in repeating something a given number of times.
+It's a short hand for a for loop without an explicit loop variable::
 
-    forever {
-        ; .. do stuff
-        if something
-            break        ; you can exit the loop if you want
+    repeat 15 {
+        ; do something...
+        break		; you can break out of the loop
     }
 
+If you omit the iteration count, it simply loops forever.
+You can still ``break`` out of such a loop if you want though.
+
 
 Conditional Execution and Jumps
 -------------------------------
@@ -702,3 +700,4 @@ case you have to use { } to enclose them::
         }
         else -> c64scr.print("don't know")
     }
+

docs/source/targetsystem.rst

@@ -113,22 +113,14 @@ CPU
 Directly Usable Registers
 -------------------------
 
-The following 6502 CPU hardware registers are directly usable in program code (and are reserved symbols):
+The hardware CPU registers are not directly accessible from regular Prog8 code.
+If you need to mess with them, you'll have to use inline assembly.
+Be extra wary of the ``X`` register because it is used as an evaluation stack pointer and
+changing its value you will destroy the evaluation stack and likely crash the program.
 
-- ``A``, ``X``, ``Y``  the three main cpu registers (8 bits)
-- the status register (P) carry flag and interrupt disable flag can be written via a couple of special
-  builtin functions (``set_carry()``, ``clear_carry()``, ``set_irqd()``,  ``clear_irqd()``),
-  and read via the ``read_flags()`` function.
-
-However, you must assume that the 3 hardware registers ``A``, ``X`` and ``Y``
-are volatile. Their values cannot be depended upon, the compiler will use them as required.
-Even simple assignments may require modification of one or more of the registers (for instance, when using arrays).
-
-Even more important, the ``X`` register is used as an evaluation stack pointer.
-If you mess with it, you will destroy the evaluation stack and likely crash your program.
-In some cases the compiler will warn you about this, but you should really avoid to use
-this register. It's possible to store/restore the register's value (using special built in functions)
-for the cases you really really need to use it directly.
+The status register (P) carry flag and interrupt disable flag can be written via a couple of special
+builtin functions (``set_carry()``, ``clear_carry()``, ``set_irqd()``,  ``clear_irqd()``),
+and read via the ``read_flags()`` function.
 
 
 Subroutine Calling Conventions
@@ -173,3 +165,4 @@ as a subroutine ``irq`` in the module ``irq`` so like this::
             ; ... irq handling here ...
         }
     }
+

docs/source/todo.rst

@@ -2,10 +2,11 @@
 TODO
 ====
 
-- finalize (most) of the still missing "new" assignment asm code generation
-- aliases for imported symbols for example perhaps '%alias print = c64scr.print'
-- option to load library files from a directory instead of the embedded ones (easier library development/debugging)
-- investigate support for 8bitguy's Commander X16 platform https://murray2.com/forums/commander-x16.9/  and https://github.com/commanderx16/x16-docs
+- optimize assignment codegeneration
+- get rid of all TODO's ;-)
+- option to load the built-in library files from a directory instead of the embedded ones (for easier library development/debugging)
+- aliases for imported symbols for example perhaps '%alias print = c64scr.print' ?
+- investigate support for 8bitguy's Commander X16 platform https://www.commanderx16.com  and https://github.com/commanderx16/x16-docs
 - see if we can group some errors together for instance the (now single) errors about unidentified symbols
 
 
@@ -17,13 +18,13 @@ Add more compiler optimizations to the existing ones.
 - more targeted optimizations for assigment asm code, such as the following:
 - subroutine calling convention? like: 1 byte arg -> pass in A, 2 bytes -> pass in A+Y, return value likewise.
 - remove unreachable code after an exit(), return or goto
-- working subroutine inlining (start with trivial routines, grow to taking care of vars and identifier refs to them)
 - add a compiler option to not include variable initialization code (useful if the program is expected to run only once, such as a game)
   the program will then rely solely on the values as they are in memory at the time of program startup.
 - Also some library routines and code patterns could perhaps be optimized further
 - can the parameter passing to subroutines be optimized to avoid copying?
 - more optimizations on the language AST level
 - more optimizations on the final assembly source level
+- note: abandoned subroutine inlining because of problems referencing non-local stuff. Can't move everything around.
 
 
 Eval stack redesign? (lot of work)

examples/arithmetic/aggregates.p8

@@ -104,17 +104,6 @@ main {
         ub = all(farr)
         if ub==0 c64scr.print("error all10\n")
 
-        check_eval_stack()
-
         c64scr.print("\nyou should see no errors printed above (only at first run).")
     }
-
-    sub check_eval_stack() {
-        if X!=255 {
-            c64scr.print("x=")
-            c64scr.print_ub(X)
-            c64scr.print(" error!\n")
-        }
-    }
-
 }

examples/arithmetic/bitshift.p8

@@ -1,11 +1,12 @@
 %import c64utils
-;%import c64flt
-;%option enable_floats
 %zeropage dontuse
 
+
 main {
 
     sub start() {
+        ubyte A
+
         c64scr.print("ubyte shift left\n")
         A = shiftlb0()
         c64scr.print_ubbin(A, true)

examples/arithmetic/div.p8

@@ -24,8 +24,6 @@ main {
 
         div_float(0,1,0)
         div_float(999.9,111.0,9.008108108108107)
-
-        check_eval_stack()
     }
 
     sub div_ubyte(ubyte a1, ubyte a2, ubyte c) {
@@ -103,12 +101,4 @@ main {
         c64flt.print_f(r)
         c64.CHROUT('\n')
     }
-
-    sub check_eval_stack() {
-        if X!=255 {
-            c64scr.print("x=")
-            c64scr.print_ub(X)
-            c64scr.print(" error!\n")
-        }
-    }
 }

examples/arithmetic/minus.p8

@@ -32,8 +32,6 @@ main {
         minus_float(0,0,0)
         minus_float(2.5,1.5,1.0)
         minus_float(-1.5,3.5,-5.0)
-
-        check_eval_stack()
     }
 
     sub minus_ubyte(ubyte a1, ubyte a2, ubyte c) {
@@ -111,13 +109,4 @@ main {
         c64flt.print_f(r)
         c64.CHROUT('\n')
     }
-
-    sub check_eval_stack() {
-        if X!=255 {
-            c64scr.print("x=")
-            c64scr.print_ub(X)
-            c64scr.print(" error!\n")
-        }
-    }
-
 }

examples/arithmetic/mult.p8

@@ -26,8 +26,6 @@ main {
         mul_float(0,0,0)
         mul_float(2.5,10,25)
         mul_float(-1.5,10,-15)
-
-        check_eval_stack()
     }
 
     sub mul_ubyte(ubyte a1, ubyte a2, ubyte c) {
@@ -105,12 +103,4 @@ main {
         c64flt.print_f(r)
         c64.CHROUT('\n')
     }
-
-    sub check_eval_stack() {
-        if X!=255 {
-            c64scr.print("x=")
-            c64scr.print_ub(X)
-            c64scr.print(" error!\n")
-        }
-    }
 }

examples/arithmetic/plus.p8

@@ -30,8 +30,6 @@ main {
         plus_float(1.5,2.5,4.0)
         plus_float(-1.5,3.5,2.0)
         plus_float(-1.1,3.3,2.2)
-
-        check_eval_stack()
     }
 
     sub plus_ubyte(ubyte a1, ubyte a2, ubyte c) {
@@ -109,13 +107,4 @@ main {
         c64flt.print_f(r)
         c64.CHROUT('\n')
     }
-
-    sub check_eval_stack() {
-        if X!=255 {
-            c64scr.print("x=")
-            c64scr.print_ub(X)
-            c64scr.print(" error!\n")
-        }
-    }
-
 }

examples/arithmetic/postincrdecr.p8

@@ -9,6 +9,7 @@ main {
 
         c64scr.plot(0,24)
 
+        ubyte Y
         ubyte ub=200
         byte bb=-100
         uword uw = 2000
@@ -76,8 +77,6 @@ main {
         check_b(barr[1], -100)
         check_uw(uwarr[1], 2000)
         check_w(warr[1], -1000)
-
-        check_eval_stack()
     }
 
     sub check_ub(ubyte value, ubyte expected) {
@@ -139,13 +138,4 @@ main {
         c64flt.print_f(expected)
         c64.CHROUT('\n')
     }
-
-
-    sub check_eval_stack() {
-        if X!=255 {
-            c64scr.print("x=")
-            c64scr.print_ub(X)
-            c64scr.print(" error!\n")
-        }
-    }
 }

examples/arithmetic/remainder.p8

@@ -15,8 +15,6 @@ main {
         remainder_uword(40000,511,142)
         remainder_uword(40000,500,0)
         remainder_uword(43211,12,11)
-
-        check_eval_stack()
     }
 
     sub remainder_ubyte(ubyte a1, ubyte a2, ubyte c) {
@@ -48,12 +46,4 @@ main {
         c64scr.print_uw(r)
         c64.CHROUT('\n')
     }
-
-    sub check_eval_stack() {
-        if X!=255 {
-            c64scr.print("x=")
-            c64scr.print_ub(X)
-            c64scr.print(" error!\n")
-        }
-    }
 }

examples/balloonflight.p8

@@ -21,7 +21,7 @@ main {
         ubyte active_height = 24
         ubyte upwards = true
 
-        forever {
+        repeat {
             ubyte mountain = 223        ; slope upwards
             if active_height < target_height {
                 active_height++

examples/bdmusic.p8

@@ -16,7 +16,7 @@ sub start() {
     void c64.CHRIN()
     c64.CLEARSCR()
 
-    forever {
+    repeat {
         uword note
         for note in notes {
             ubyte note1 = lsb(note)
@@ -37,10 +37,9 @@ sub start() {
 }
 
 sub delay() {
-    ubyte d
-    for d in 0 to 12 {
-        while c64.RASTER!=0 {
-            ; tempo delay synced to screen refresh
+    repeat 8 {
+        ubyte jiffy = c64.TIME_LO
+        while c64.TIME_LO==jiffy {
         }
     }
 }

examples/c64graphics.p8

@@ -39,7 +39,7 @@ graphics {
 
         if dx >= dy {
             if positive_ix {
-                forever {
+                repeat {
                     plot(y1)
                     if plotx==x2
                         return
@@ -51,7 +51,7 @@ graphics {
                     }
                 }
             } else {
-                forever {
+                repeat {
                     plot(y1)
                     if plotx==x2
                         return
@@ -66,7 +66,7 @@ graphics {
         }
         else {
             if positive_ix {
-                forever {
+                repeat {
                     plot(y1)
                     if y1 == y2
                         return
@@ -78,7 +78,7 @@ graphics {
                     }
                 }
             } else {
-                forever {
+                repeat {
                     plot(y1)
                     if y1 == y2
                         return

examples/comparison_ifs_byte.p8

@@ -105,16 +105,5 @@ main {
             c64scr.print("ok: 22 >= 22\n")
         else
             c64scr.print("error in 22>=22!\n")
-
-        check_eval_stack()
-    }
-
-
-    sub check_eval_stack() {
-        if X!=255 {
-            c64scr.print("x=")
-            c64scr.print_ub(X)
-            c64scr.print(" error!\n")
-        }
     }
 }

examples/comparison_ifs_float.p8

@@ -105,16 +105,5 @@ main {
             c64scr.print("ok: -22.2 >= -22.2\n")
         else
             c64scr.print("error in -22.2>=-22.2!\n")
-
-        check_eval_stack()
     }
-
-    sub check_eval_stack() {
-        if X!=255 {
-            c64scr.print("x=")
-            c64scr.print_ub(X)
-            c64scr.print(" error!\n")
-        }
-    }
-
 }

examples/comparison_ifs_ubyte.p8

@@ -105,16 +105,5 @@ main {
             c64scr.print("ok: 22 >= 22\n")
         else
             c64scr.print("error in 22>=22!\n")
-
-        check_eval_stack()
     }
-
-    sub check_eval_stack() {
-        if X!=255 {
-            c64scr.print("x=")
-            c64scr.print_ub(X)
-            c64scr.print(" error!\n")
-        }
-    }
-
 }

examples/comparison_ifs_uword.p8

@@ -105,16 +105,5 @@ main {
             c64scr.print("ok: 322 >= 322\n")
         else
             c64scr.print("error in 322>=322!\n")
-
-        check_eval_stack()
     }
-
-    sub check_eval_stack() {
-        if X!=255 {
-            c64scr.print("x=")
-            c64scr.print_ub(X)
-            c64scr.print(" error!\n")
-        }
-    }
-
 }

examples/comparison_ifs_word.p8

@@ -137,16 +137,5 @@ main {
             c64scr.print("ok: 1000 >= 1000\n")
         else
             c64scr.print("error in 1000>=1000!\n")
-
-        check_eval_stack()
     }
-
-    sub check_eval_stack() {
-        if X!=255 {
-            c64scr.print("x=")
-            c64scr.print_ub(X)
-            c64scr.print(" error!\n")
-        }
-    }
-
 }

examples/comparisons_byte.p8

@@ -52,7 +52,6 @@ main {
         c64scr.print("v1=20, v2=-111\n")
         compare()
 
-        check_eval_stack()
         return
 
         sub compare() {
@@ -91,13 +90,4 @@ main {
     }
 
     }
-
-    sub check_eval_stack() {
-        if X!=255 {
-            c64scr.print("x=")
-            c64scr.print_ub(X)
-            c64scr.print(" error!\n")
-        }
-    }
-
 }

examples/comparisons_float.p8

@@ -68,7 +68,6 @@ main {
         c64scr.print("v1 = v2 = 0\n")
         compare()
 
-        check_eval_stack()
         return
 
         sub compare() {
@@ -108,11 +107,4 @@ main {
 
     }
 
-    sub check_eval_stack() {
-        if X!=255 {
-            c64scr.print("x=")
-            c64scr.print_ub(X)
-            c64scr.print(" error!\n")
-        }
-    }
 }

examples/comparisons_ubyte.p8

@@ -52,7 +52,6 @@ main {
         c64scr.print("v1=220, v2=10\n")
         compare()
 
-        check_eval_stack()
         return
 
         sub compare() {
@@ -92,12 +91,4 @@ main {
 
     }
 
-    sub check_eval_stack() {
-        if X!=255 {
-            c64scr.print("x=")
-            c64scr.print_ub(X)
-            c64scr.print(" error!\n")
-        }
-    }
-
 }

examples/comparisons_uword.p8

@@ -82,7 +82,6 @@ main {
         c64scr.print("v1 = v2 = aa\n")
         compare()
 
-        check_eval_stack()
         return
 
         sub compare() {
@@ -121,13 +120,4 @@ main {
     }
 
     }
-
-    sub check_eval_stack() {
-        if X!=255 {
-            c64scr.print("x=")
-            c64scr.print_ub(X)
-            c64scr.print(" error!\n")
-        }
-    }
-
 }

examples/comparisons_word.p8

@@ -118,7 +118,6 @@ main {
         c64scr.print("v1 = v2 = aa\n")
         compare()
 
-        check_eval_stack()
         return
 
         sub compare() {
@@ -157,13 +156,4 @@ main {
     }
 
     }
-
-    sub check_eval_stack() {
-        if X!=255 {
-            c64scr.print("x=")
-            c64scr.print_ub(X)
-            c64scr.print(" error!\n")
-        }
-    }
-
 }

examples/cube3d-float.p8

@@ -19,7 +19,7 @@ main {
 
     sub start()  {
         float time=0.0
-        forever {
+        repeat {
             rotate_vertices(time)
             c64scr.clear_screenchars(32)
             draw_edges()

examples/cube3d-sprites.p8

@@ -1,6 +1,7 @@
 %import c64lib
 %import c64utils
 
+
 spritedata $2000 {
     ; this memory block contains the sprite data
     ; it must start on an address aligned to 64 bytes.
@@ -81,7 +82,7 @@ main {
         uword anglex
         uword angley
         uword anglez
-        forever {
+        repeat {
             c64.TIME_LO=0
             rotate_vertices(msb(anglex), msb(angley), msb(anglez))
             position_sprites()

examples/cube3d.p8

@@ -21,7 +21,7 @@ main {
         uword anglex
         uword angley
         uword anglez
-        forever {
+        repeat {
             rotate_vertices(msb(anglex), msb(angley), msb(anglez))
             c64scr.clear_screenchars(32)
             draw_edges()

examples/fibonacci.p8

@@ -6,7 +6,8 @@
 main {
     sub start() {
         c64scr.print("fibonacci sequence\n")
-        for A in 0 to 20 {
+
+        repeat 21 {
             c64scr.print_uw(fib_next())
             c64.CHROUT('\n')
         }

examples/hello.p8

@@ -42,17 +42,5 @@ main {
         c64.CHROUT('\n')
 
         c64scr.print("bye!\n")
-
-        check_eval_stack()
     }
-
-
-    sub check_eval_stack() {
-        if X!=255 {
-            c64scr.print("stack x=")
-            c64scr.print_ub(X)
-            c64scr.print(" error!\n")
-        }
-    }
-
 }

examples/line-circle-gfx.p8

@@ -7,7 +7,7 @@ main {
         graphics.enable_bitmap_mode()
         draw_lines()
         draw_circles()
-        forever {
+        repeat {
         }
     }
 

examples/line-circle-txt.p8

@@ -77,7 +77,7 @@ main {
             ubyte y = y1
 
             if dx >= dy {
-                forever {
+                repeat {
                     c64scr.setcc(x, y, 42, 5)
                     if x==x2
                         return
@@ -89,7 +89,7 @@ main {
                     }
                 }
             } else {
-                forever {
+                repeat {
                     c64scr.setcc(x, y, 42, 5)
                     if y == y2
                         return

examples/mandelbrot-gfx.p8

@@ -0,0 +1,51 @@
+%import c64lib
+%import c64flt
+%import c64graphics
+%zeropage floatsafe
+
+; Draw a mandelbrot in graphics mode (the image will be 256 x 200 pixels).
+; NOTE: this will take an eternity to draw on a real c64.
+; even in Vice in warp mode (700% speed on my machine) it's slow, but you can see progress
+
+main {
+    const ubyte width = 255
+    const ubyte height = 200
+    const ubyte max_iter = 16
+
+    sub start()  {
+        graphics.enable_bitmap_mode()
+
+        ubyte pixelx
+        ubyte pixely
+
+        for pixely in 0 to height-1 {
+            float yy = (pixely as float)/0.4/height - 1.0
+
+            for pixelx in 0 to width-1 {
+                float xx = (pixelx as float)/0.3/width - 2.2
+
+                float xsquared = 0.0
+                float ysquared = 0.0
+                float x = 0.0
+                float y = 0.0
+                ubyte iter = 0
+
+                while iter<max_iter and xsquared+ysquared<4.0 {
+                    y = x*y*2.0 + yy
+                    x = xsquared - ysquared + xx
+                    xsquared = x*x
+                    ysquared = y*y
+                    iter++
+                }
+
+                if iter & 1 {
+                    graphics.plotx = pixelx
+                    graphics.plot(pixely)
+                }
+            }
+        }
+
+        repeat {
+        }
+    }
+}

examples/mandelbrot.p8

@@ -30,7 +30,7 @@ main {
                 float y = 0.0
                 ubyte iter = 0
 
-                while (iter<max_iter and xsquared+ysquared<4.0) {
+                while iter<max_iter and xsquared+ysquared<4.0 {
                     y = x*y*2.0 + yy
                     x = xsquared - ysquared + xx
                     xsquared = x*x
@@ -48,15 +48,5 @@ main {
         c64scr.print("finished in ")
         c64flt.print_f(duration)
         c64scr.print(" seconds!\n")
-        check_eval_stack()
     }
-
-    sub check_eval_stack() {
-        if X!=255 {
-            c64scr.print("stack x=")
-            c64scr.print_ub(X)
-            c64scr.print(" error!\n")
-        }
-    }
-
 }

examples/numbergame.p8

@@ -57,18 +57,6 @@ main {
             c64scr.print("Thanks for playing, ")
             c64scr.print(name)
             c64scr.print(".\n")
-
-            check_eval_stack()
         }
     }
-
-
-    sub check_eval_stack() {
-        if X!=255 {
-            c64scr.print("stack x=")
-            c64scr.print_ub(X)
-            c64scr.print(" error!\n")
-        }
-    }
-
 }

examples/plasma.p8

@@ -0,0 +1,101 @@
+%import c64lib
+
+
+;/*****************************************************************************\
+;** plasma test program for cc65.                                             **
+;**                                                                           **
+;** (w)2001 by groepaz/hitmen                                                 **
+;**                                                                           **
+;** Cleanup and porting by Ullrich von Bassewitz.                             **
+;** Converted to prog8 by Irmen de Jong                                       **
+;**                                                                           **
+;\*****************************************************************************/
+
+main {
+    const uword SCREEN1 = $E000
+    const uword SCREEN2 = $E400
+    const uword CHARSET = $E800
+
+    const ubyte PAGE1 = ((SCREEN1 >> 6) & $F0) | ((CHARSET >> 10) & $0E)
+    const ubyte PAGE2 = ((SCREEN2 >> 6) & $F0) | ((CHARSET >> 10) & $0E)
+
+    sub start() {
+        c64.COLOR = 1
+        c64scr.print("creating charset...\n")
+        makechar()
+
+        ubyte block = c64.CIA2PRA
+        ; ubyte v = c64.VMCSB
+        c64.CIA2PRA = (block & $FC) | (lsb(SCREEN1 >> 14) ^ $03)
+
+        repeat {
+            doplasma(SCREEN1)
+            c64.VMCSB = PAGE1
+            doplasma(SCREEN2)
+            c64.VMCSB = PAGE2
+        }
+
+        ; restore screen (if you want)
+        ;c64.VMCSB = v
+        ;c64.CIA2PRA = block
+        ;c64scr.print("done!\n")
+    }
+
+    ; several variables outside of doplasma to make them retain their value
+    ubyte c1A
+    ubyte c1B
+    ubyte c2A
+    ubyte c2B
+
+    sub doplasma(uword screen) {
+        ubyte[40] xbuf
+        ubyte[25] ybuf
+        ubyte c1a = c1A
+        ubyte c1b = c1B
+        ubyte c2a = c2A
+        ubyte c2b = c2B
+        ubyte @zp x
+        ubyte @zp y
+
+        for y in 0 to 24 {
+            ybuf[y] = sin8u(c1a) + sin8u(c1b)
+            c1a += 4
+            c1b += 9
+        }
+        c1A += 3
+        c1B -= 5
+        for x in 0 to 39 {
+            xbuf[x] = sin8u(c2a) + sin8u(c2b)
+            c2a += 3
+            c2b += 7
+        }
+        c2A += 2
+        c2B -= 3
+        for y in 0 to 24 {
+            for x in 0 to 39 {
+                @(screen) = xbuf[x] + ybuf[y]
+                screen++
+            }
+        }
+    }
+
+    sub makechar() {
+        ubyte[8] bittab = [ $01, $02, $04, $08, $10, $20, $40, $80 ]
+        ubyte c
+        for c in 0 to 255 {
+            ubyte @zp s = sin8u(c)
+            ubyte i
+            for i in 0 to 7 {
+                ubyte b=0
+                ubyte @zp ii
+                for ii in 0 to 7 {
+                    ; use 16 bit rng for a bit more randomness instead of the 8-bit rng
+                    if lsb(rndw()) > s {
+                        b |= bittab[ii]
+                    }
+                }
+                @(CHARSET + i + c*8.w) = b
+            }
+        }
+    }
+}

examples/primes.p8

@@ -12,7 +12,7 @@ main {
         ; calculate primes
         c64scr.print("prime numbers up to 255:\n\n")
         ubyte amount=0
-        forever {
+        repeat {
             ubyte prime = find_next_prime()
             if prime==0
                 break
@@ -24,8 +24,6 @@ main {
         c64scr.print("number of primes (expected 54): ")
         c64scr.print_ub(amount)
         c64.CHROUT('\n')
-
-        check_eval_stack()
     }
 
 
@@ -48,14 +46,4 @@ main {
         }
         return candidate_prime
     }
-
-
-
-    sub check_eval_stack() {
-        if X!=255 {
-            c64scr.print("stack x=")
-            c64scr.print_ub(X)
-            c64scr.print(" error!\n")
-        }
-    }
 }

examples/rasterbars.p8

@@ -7,7 +7,7 @@ main {
         c64.SCROLY &= %11101111             ; blank the screen
         c64utils.set_rasterirq_excl(40)     ; register exclusive raster irq handler
 
-        forever {
+        repeat {
             ; enjoy the moving bars :)
         }
 

examples/romfloats.p8

@@ -52,17 +52,5 @@ main {
 
         c64flt.print_f(0.0)
         c64.CHROUT('\n')
-
-        check_eval_stack()
     }
-
-
-    sub check_eval_stack() {
-        if X!=255 {
-            c64scr.print("stack x=")
-            c64scr.print_ub(X)
-            c64scr.print(" error!\n")
-        }
-    }
-
 }

examples/screencodes.p8

@@ -34,17 +34,5 @@ main {
         c64scr.print("\nscreencode z=")
         c64scr.print_ub(c2)
         c64scr.print("\n")
-
-        check_eval_stack()
-    }
-
-
-
-    sub check_eval_stack() {
-        if X!=255 {
-            c64scr.print("stack x=")
-            c64scr.print_ub(X)
-            c64scr.print(" error!\n")
-        }
     }
 }

examples/sorting.p8

@@ -30,7 +30,6 @@ main {
         c64scr.print("reversed\n")
         print_arrays()
 
-        check_eval_stack()
         return
 
 
@@ -65,14 +64,4 @@ main {
             c64.CHROUT('\n')
         }
     }
-
-
-    sub check_eval_stack() {
-        if X!=255 {
-            c64scr.print("stack x=")
-            c64scr.print_ub(X)
-            c64scr.print(" error!\n")
-        }
-    }
-
 }

examples/structs.p8

@@ -11,7 +11,7 @@ main {
 
     sub start() {
 
-        Color purple = {255, 0, 255}
+        Color purple = [255, 0, 255]
 
         Color other
 
@@ -27,17 +27,5 @@ main {
         c64.CHROUT(',')
         c64scr.print_ub(other.blue)
         c64.CHROUT('\n')
-
-        check_eval_stack()
     }
-
-
-    sub check_eval_stack() {
-        if X!=255 {
-            c64scr.print("stack x=")
-            c64scr.print_ub(X)
-            c64scr.print(" error!\n")
-        }
-    }
-
 }

examples/swirl-float.p8

@@ -11,11 +11,9 @@ main {
         float t
         ubyte color
 
-        forever {
-            float x = sin(t)
-            float y = cos(t*1.1356)
-            ubyte xx=(x * width/2.2) + width/2.0 as ubyte
-            ubyte yy=(y * height/2.2) + height/2.0 as ubyte
+        repeat {
+            ubyte xx=(sin(t) * width/2.2) + width/2.0 as ubyte
+            ubyte yy=(cos(t*1.1356) * height/2.2) + height/2.0 as ubyte
             c64scr.setcc(xx, yy, 81, color)
             t  += 0.08
             color++

examples/swirl.p8

@@ -15,7 +15,7 @@ main {
 
         Ball ball
 
-        forever {
+        repeat {
             ubyte x = msb(sin8u(msb(ball.anglex)) as uword * width)
             ubyte y = msb(cos8u(msb(ball.angley)) as uword * height)
             c64scr.setcc(x, y, 81, ball.color)

examples/tehtriz.p8

@@ -7,6 +7,7 @@
 ;   staged speed increase
 ;   some simple sound effects
 
+
 main {
 
     const ubyte boardOffsetX = 14
@@ -38,8 +39,6 @@ newgame:
         spawnNextBlock()
 
 waitkey:
-        check_eval_stack()
-
         if c64.TIME_LO>=(60-4*speedlevel) {
             c64.TIME_LO = 0
 
@@ -107,6 +106,7 @@ waitkey:
                 break
             }
         }
+
         if dropypos>ypos {
             ypos = dropypos
             sound.blockdrop()
@@ -389,16 +389,6 @@ waitkey:
                 c64scr.setcc((i&3)+x, (i/4)+y, character, c)
         }
     }
-
-
-    sub check_eval_stack() {
-        if X!=255 {
-            c64scr.print("stack x=")
-            c64scr.print_ub(X)
-            c64scr.print(" error!\n")
-        }
-    }
-
 }