version 4.5

compiler/res/prog8lib/c64/syslib.p8

@@ -204,19 +204,19 @@ romsub $FFB4 = TALK(ubyte device @ A) clobbers(A)               ; command serial
 romsub $FFB7 = READST() -> ubyte @ A                            ; read I/O status word
 romsub $FFBA = SETLFS(ubyte logical @ A, ubyte device @ X, ubyte address @ Y)   ; set logical file parameters
 romsub $FFBD = SETNAM(ubyte namelen @ A, str filename @ XY)     ; set filename parameters
-romsub $FFC0 = OPEN() clobbers(A,X,Y)                           ; (via 794 ($31A)) open a logical file
+romsub $FFC0 = OPEN() clobbers(X,Y) -> ubyte @Pc, ubyte @A      ; (via 794 ($31A)) open a logical file
 romsub $FFC3 = CLOSE(ubyte logical @ A) clobbers(A,X,Y)         ; (via 796 ($31C)) close a logical file
-romsub $FFC6 = CHKIN(ubyte logical @ X) clobbers(A,X)           ; (via 798 ($31E)) define an input channel
+romsub $FFC6 = CHKIN(ubyte logical @ X) clobbers(A,X) -> ubyte @Pc    ; (via 798 ($31E)) define an input channel
 romsub $FFC9 = CHKOUT(ubyte logical @ X) clobbers(A,X)          ; (via 800 ($320)) define an output channel
 romsub $FFCC = CLRCHN() clobbers(A,X)                           ; (via 802 ($322)) restore default devices
-romsub $FFCF = CHRIN() clobbers(Y) -> ubyte @ A                 ; (via 804 ($324)) input a character (for keyboard, read a whole line from the screen) A=byte read.
+romsub $FFCF = CHRIN() clobbers(X, Y) -> ubyte @ A   ; (via 804 ($324)) input a character (for keyboard, read a whole line from the screen) A=byte read.
 romsub $FFD2 = CHROUT(ubyte char @ A)                           ; (via 806 ($326)) output a character
 romsub $FFD5 = LOAD(ubyte verify @ A, uword address @ XY) -> ubyte @Pc, ubyte @ A, ubyte @ X, ubyte @ Y     ; (via 816 ($330)) load from device
 romsub $FFD8 = SAVE(ubyte zp_startaddr @ A, uword endaddr @ XY) -> ubyte @ Pc, ubyte @ A                    ; (via 818 ($332)) save to a device
 romsub $FFDB = SETTIM(ubyte low @ A, ubyte middle @ X, ubyte high @ Y)      ; set the software clock
 romsub $FFDE = RDTIM() -> ubyte @ A, ubyte @ X, ubyte @ Y       ; read the software clock
-romsub $FFE1 = STOP() clobbers(A,X) -> ubyte @ Pz, ubyte @ Pc   ; (via 808 ($328)) check the STOP key
-romsub $FFE4 = GETIN() clobbers(X,Y) -> ubyte @ A               ; (via 810 ($32A)) get a character
+romsub $FFE1 = STOP() clobbers(X) -> ubyte @ Pz, ubyte @ A      ; (via 808 ($328)) check the STOP key (and some others in A)
+romsub $FFE4 = GETIN() clobbers(X,Y) -> ubyte @Pc, ubyte @ A    ; (via 810 ($32A)) get a character
 romsub $FFE7 = CLALL() clobbers(A,X)                            ; (via 812 ($32C)) close all files
 romsub $FFEA = UDTIM() clobbers(A,X)                            ; update the software clock
 romsub $FFED = SCREEN() -> ubyte @ X, ubyte @ Y                 ; read number of screen rows and columns

compiler/res/prog8lib/conv.p8

@@ -249,6 +249,28 @@ output	.text  "0000", $00      ; 0-terminated output buffer (to make printing ea
 	}}
 }
 
+
+asmsub str2ubyte(str string @ AY) clobbers(Y) -> ubyte @A {
+	; -- returns the unsigned byte value of the string number argument in AY
+	;    the number may NOT be preceded by a + sign and may NOT contain spaces
+	;    (any non-digit character will terminate the number string that is parsed)
+	; TODO implement optimized custom version of this instead of simply reusing str2uword
+	%asm {{
+    	jmp  str2uword
+	}}
+}
+
+
+asmsub str2byte(str string @ AY) clobbers(Y) -> ubyte @A {
+	; -- returns the signed byte value of the string number argument in AY
+	;    the number may be preceded by a + or - sign but may NOT contain spaces
+	;    (any non-digit character will terminate the number string that is parsed)
+	; TODO implement optimized custom version of this instead of simply reusing str2word
+	%asm {{
+    	jmp  str2word
+	}}
+}
+
 asmsub str2uword(str string @ AY) -> uword @ AY {
 	; -- returns the unsigned word value of the string number argument in AY
 	;    the number may NOT be preceded by a + sign and may NOT contain spaces

compiler/res/prog8lib/cx16/floats.p8

@@ -78,10 +78,10 @@ asmsub  GIVUAYFAY  (uword value @ AY) clobbers(A,X,Y)  {
 	; ---- unsigned 16 bit word in A/Y (lo/hi) to fac1
 	%asm {{
         phx
-        sta  P8ZP_SCRATCH_REG
+        sta  P8ZP_SCRATCH_W2
         sty  P8ZP_SCRATCH_B1
         tya
-        ldy  P8ZP_SCRATCH_REG
+        ldy  P8ZP_SCRATCH_W2
         jsr  GIVAYF                 ; load it as signed... correct afterwards
         lda  P8ZP_SCRATCH_B1
 	    bpl  +
@@ -98,9 +98,9 @@ _flt65536    .byte 145,0,0,0,0       ; 65536.0
 asmsub  GIVAYFAY  (uword value @ AY) clobbers(A,X,Y)  {
 	; ---- signed 16 bit word in A/Y (lo/hi) to float in fac1
 	%asm {{
-		sta  P8ZP_SCRATCH_REG
+		sta  P8ZP_SCRATCH_W2
 		tya
-		ldy  P8ZP_SCRATCH_REG
+		ldy  P8ZP_SCRATCH_W2
 		jmp  GIVAYF		; this uses the inverse order, Y/A
 	}}
 }

compiler/res/prog8lib/cx16/syslib.p8

@@ -16,44 +16,44 @@ c64 {
 ; CLEARSCR -> use screen.clear_screen
 ; HOMECRSR -> use screen.plot
 
-romsub $FF81 = CINT()  clobbers(A,X,Y)                           ; (alias: SCINIT) initialize screen editor and video chip
-romsub $FF84 = IOINIT()  clobbers(A, X)                          ; initialize I/O devices (CIA, SID, IRQ)
-romsub $FF87 = RAMTAS()  clobbers(A,X,Y)                         ; initialize RAM, tape buffer, screen
-romsub $FF8A = RESTOR()  clobbers(A,X,Y)                         ; restore default I/O vectors
-romsub $FF8D = VECTOR(uword userptr @ XY, ubyte dir @ Pc)  clobbers(A,Y)     ; read/set I/O vector table
+romsub $FF81 = CINT() clobbers(A,X,Y)                           ; (alias: SCINIT) initialize screen editor and video chip
+romsub $FF84 = IOINIT() clobbers(A, X)                          ; initialize I/O devices (CIA, SID, IRQ)
+romsub $FF87 = RAMTAS() clobbers(A,X,Y)                         ; initialize RAM, tape buffer, screen
+romsub $FF8A = RESTOR() clobbers(A,X,Y)                         ; restore default I/O vectors
+romsub $FF8D = VECTOR(uword userptr @ XY, ubyte dir @ Pc) clobbers(A,Y)     ; read/set I/O vector table
 romsub $FF90 = SETMSG(ubyte value @ A)                          ; set Kernal message control flag
-romsub $FF93 = SECOND(ubyte address @ A)  clobbers(A)            ; (alias: LSTNSA) send secondary address after LISTEN
-romsub $FF96 = TKSA(ubyte address @ A)  clobbers(A)              ; (alias: TALKSA) send secondary address after TALK
-romsub $FF99 = MEMTOP(uword address @ XY, ubyte dir @ Pc) -> ubyte @A, uword @ XY     ; read/set top of memory  pointer, returns number of banks in A
+romsub $FF93 = SECOND(ubyte address @ A) clobbers(A)            ; (alias: LSTNSA) send secondary address after LISTEN
+romsub $FF96 = TKSA(ubyte address @ A) clobbers(A)              ; (alias: TALKSA) send secondary address after TALK
+romsub $FF99 = MEMTOP(uword address @ XY, ubyte dir @ Pc) -> uword @ XY     ; read/set top of memory  pointer
 romsub $FF9C = MEMBOT(uword address @ XY, ubyte dir @ Pc) -> uword @ XY     ; read/set bottom of memory  pointer
-romsub $FF9F = SCNKEY()  clobbers(A,X,Y)                         ; scan the keyboard
+romsub $FF9F = SCNKEY() clobbers(A,X,Y)                         ; scan the keyboard
 romsub $FFA2 = SETTMO(ubyte timeout @ A)                        ; set time-out flag for IEEE bus
 romsub $FFA5 = ACPTR() -> ubyte @ A                             ; (alias: IECIN) input byte from serial bus
 romsub $FFA8 = CIOUT(ubyte databyte @ A)                        ; (alias: IECOUT) output byte to serial bus
-romsub $FFAB = UNTLK()  clobbers(A)                              ; command serial bus device to UNTALK
-romsub $FFAE = UNLSN()  clobbers(A)                              ; command serial bus device to UNLISTEN
-romsub $FFB1 = LISTEN(ubyte device @ A)  clobbers(A)             ; command serial bus device to LISTEN
-romsub $FFB4 = TALK(ubyte device @ A)  clobbers(A)               ; command serial bus device to TALK
+romsub $FFAB = UNTLK() clobbers(A)                              ; command serial bus device to UNTALK
+romsub $FFAE = UNLSN() clobbers(A)                              ; command serial bus device to UNLISTEN
+romsub $FFB1 = LISTEN(ubyte device @ A) clobbers(A)             ; command serial bus device to LISTEN
+romsub $FFB4 = TALK(ubyte device @ A) clobbers(A)               ; command serial bus device to TALK
 romsub $FFB7 = READST() -> ubyte @ A                            ; read I/O status word
 romsub $FFBA = SETLFS(ubyte logical @ A, ubyte device @ X, ubyte address @ Y)   ; set logical file parameters
 romsub $FFBD = SETNAM(ubyte namelen @ A, str filename @ XY)     ; set filename parameters
-romsub $FFC0 = OPEN()  clobbers(A,X,Y)                           ; (via 794 ($31A)) open a logical file
-romsub $FFC3 = CLOSE(ubyte logical @ A)  clobbers(A,X,Y)         ; (via 796 ($31C)) close a logical file
-romsub $FFC6 = CHKIN(ubyte logical @ X)  clobbers(A,X)           ; (via 798 ($31E)) define an input channel
-romsub $FFC9 = CHKOUT(ubyte logical @ X)  clobbers(A,X)          ; (via 800 ($320)) define an output channel
-romsub $FFCC = CLRCHN()  clobbers(A,X)                           ; (via 802 ($322)) restore default devices
-romsub $FFCF = CHRIN()  clobbers(Y) -> ubyte @ A                 ; (via 804 ($324)) input a character (for keyboard, read a whole line from the screen) A=byte read.
+romsub $FFC0 = OPEN() clobbers(X,Y) -> ubyte @Pc, ubyte @A      ; (via 794 ($31A)) open a logical file
+romsub $FFC3 = CLOSE(ubyte logical @ A) clobbers(A,X,Y)         ; (via 796 ($31C)) close a logical file
+romsub $FFC6 = CHKIN(ubyte logical @ X) clobbers(A,X) -> ubyte @Pc    ; (via 798 ($31E)) define an input channel
+romsub $FFC9 = CHKOUT(ubyte logical @ X) clobbers(A,X)          ; (via 800 ($320)) define an output channel
+romsub $FFCC = CLRCHN() clobbers(A,X)                           ; (via 802 ($322)) restore default devices
+romsub $FFCF = CHRIN() clobbers(X, Y) -> ubyte @ A   ; (via 804 ($324)) input a character (for keyboard, read a whole line from the screen) A=byte read.
 romsub $FFD2 = CHROUT(ubyte char @ A)                           ; (via 806 ($326)) output a character
 romsub $FFD5 = LOAD(ubyte verify @ A, uword address @ XY) -> ubyte @Pc, ubyte @ A, ubyte @ X, ubyte @ Y     ; (via 816 ($330)) load from device
 romsub $FFD8 = SAVE(ubyte zp_startaddr @ A, uword endaddr @ XY) -> ubyte @ Pc, ubyte @ A                    ; (via 818 ($332)) save to a device
 romsub $FFDB = SETTIM(ubyte low @ A, ubyte middle @ X, ubyte high @ Y)      ; set the software clock
 romsub $FFDE = RDTIM() -> ubyte @ A, ubyte @ X, ubyte @ Y       ; read the software clock
-romsub $FFE1 = STOP()  clobbers(A,X) -> ubyte @ Pz, ubyte @ Pc   ; (via 808 ($328)) check the STOP key
-romsub $FFE4 = GETIN()  clobbers(X,Y) -> ubyte @ A               ; (via 810 ($32A)) get a character
-romsub $FFE7 = CLALL()  clobbers(A,X)                            ; (via 812 ($32C)) close all files
-romsub $FFEA = UDTIM()  clobbers(A,X)                            ; update the software clock
+romsub $FFE1 = STOP() clobbers(X) -> ubyte @ Pz, ubyte @ A      ; (via 808 ($328)) check the STOP key (and some others in A)
+romsub $FFE4 = GETIN() clobbers(X,Y) -> ubyte @Pc, ubyte @ A    ; (via 810 ($32A)) get a character
+romsub $FFE7 = CLALL() clobbers(A,X)                            ; (via 812 ($32C)) close all files
+romsub $FFEA = UDTIM() clobbers(A,X)                            ; update the software clock
 romsub $FFED = SCREEN() -> ubyte @ X, ubyte @ Y                 ; read number of screen rows and columns
-romsub $FFF0 = PLOT(ubyte col @ Y, ubyte row @ X, ubyte dir @ Pc) -> ubyte @ X, ubyte @ Y       ; read/set position of cursor on screen.  Use screen.plot for a 'safe' wrapper that preserves X.
+romsub $FFF0 = PLOT(ubyte col @ Y, ubyte row @ X, ubyte dir @ Pc) -> ubyte @ X, ubyte @ Y       ; read/set position of cursor on screen.  Use c64scr.plot for a 'safe' wrapper that preserves X.
 romsub $FFF3 = IOBASE() -> uword @ XY                           ; read base address of I/O devices
 
 }

compiler/res/prog8lib/math.asm

@@ -781,7 +781,7 @@ mul_byte_3	.proc
 		sta  P8ZP_SCRATCH_REG
 		asl  a
 		clc
-		adc  P8P_P8ZP_SCRATCH_REG
+		adc  P8ZP_SCRATCH_REG
 		rts
 		.pend
 

compiler/res/prog8lib/prog8_lib.asm

@@ -682,6 +682,7 @@ func_read_flags	.proc
 
 
 func_sqrt16	.proc
+		; TODO is this one faster?  http://6502org.wikidot.com/software-math-sqrt
 		lda  P8ESTACK_LO+1,x
 		sta  P8ZP_SCRATCH_W2
 		lda  P8ESTACK_HI+1,x
@@ -1976,7 +1977,7 @@ ror2_array_uw	.proc
 
 
 strcpy		.proc
-		; copy a string (0-terminated) from A/Y to (ZPWORD1)
+		; copy a string (must be 0-terminated) from A/Y to (P8ZP_SCRATCH_W1)
 		; it is assumed the target string is large enough.
 		sta  P8ZP_SCRATCH_W2
 		sty  P8ZP_SCRATCH_W2+1

compiler/res/prog8lib/prog8_lib.p8

@@ -5,5 +5,5 @@
 ; indent format: TABS, size=8
 
 prog8_lib {
-	%asminclude "library:prog8lib.asm", ""
+	%asminclude "library:prog8_lib.asm", ""
 }

compiler/res/version.txt

@@ -1 +1 @@
-4.4
+4.5

compiler/src/prog8/ast/AstToplevel.kt

@@ -6,6 +6,7 @@ import prog8.ast.expressions.IdentifierReference
 import prog8.ast.processing.AstWalker
 import prog8.ast.processing.IAstVisitor
 import prog8.ast.statements.*
+import prog8.compiler.target.c64.codegen.AsmGen
 import prog8.functions.BuiltinFunctions
 import java.nio.file.Path
 
@@ -44,11 +45,19 @@ interface IFunctionCall {
     var args: MutableList<Expression>
 }
 
+
+class AsmGenInfo {
+    var usedRegsaveA = false
+    var usedRegsaveX = false
+    var usedRegsaveY = false
+}
+
 interface INameScope {
     val name: String
     val position: Position
     val statements: MutableList<Statement>
     val parent: Node
+    val asmGenInfo: AsmGenInfo
 
     fun linkParents(parent: Node)
 
@@ -260,10 +269,14 @@ class Module(override val name: String,
 
     override lateinit var parent: Node
     lateinit var program: Program
+    override val asmGenInfo = AsmGenInfo()
     val importedBy = mutableListOf<Module>()
     val imports = mutableSetOf<Module>()
 
-    var loadAddress: Int = 0        // can be set with the %address directive
+    val loadAddress: Int by lazy {
+        val address = (statements.singleOrNull { it is Directive && it.directive == "%address" } as? Directive)?.args?.single()?.int ?: 0
+        address
+    }
 
     override fun linkParents(parent: Node) {
         this.parent = parent
@@ -290,6 +303,7 @@ class GlobalNamespace(val modules: List<Module>): Node, INameScope {
     override val position = Position("<<<global>>>", 0, 0, 0)
     override val statements = mutableListOf<Statement>()
     override var parent: Node = ParentSentinel
+    override val asmGenInfo = AsmGenInfo()
 
     override fun linkParents(parent: Node) {
         modules.forEach { it.linkParents(this) }
@@ -342,6 +356,7 @@ object BuiltinFunctionScopePlaceholder : INameScope {
     override val position = Position("<<placeholder>>", 0, 0, 0)
     override var statements = mutableListOf<Statement>()
     override var parent: Node = ParentSentinel
+    override val asmGenInfo = AsmGenInfo()
     override fun linkParents(parent: Node) {}
 }
 

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

@@ -647,7 +647,21 @@ private fun prog8Parser.VardeclContext.toAst(): VarDecl {
     )
 }
 
-internal fun escape(str: String) = str.replace("\t", "\\t").replace("\n", "\\n").replace("\r", "\\r")
+internal fun escape(str: String): String {
+    val es2 = str.replace("\t", "\\t").replace("\n", "\\n").replace("\r", "\\r")
+    val es = str.map {
+        when(it) {
+            '\t' -> "\\t"
+            '\n' -> "\\n"
+            '\r' -> "\\r"
+            '"' -> "\\\""
+            in '\u8000'..'\u80ff' -> "\\x" + (it.toInt() - 0x8000).toString(16).padStart(2, '0')
+            in '\u0000'..'\u00ff' -> it.toString()
+            else -> "\\u" + it.toInt().toString(16).padStart(4, '0')
+        }
+    }
+    return es.joinToString("")
+}
 
 internal fun unescape(str: String, position: Position): String {
     val result = mutableListOf<Char>()
@@ -661,9 +675,15 @@ internal fun unescape(str: String, position: Position): String {
                 'n' -> '\n'
                 'r' -> '\r'
                 '"' -> '"'
+                '\'' -> '\''
                 'u' -> {
                     "${iter.nextChar()}${iter.nextChar()}${iter.nextChar()}${iter.nextChar()}".toInt(16).toChar()
                 }
+                'x' -> {
+                    // special hack 0x8000..0x80ff  will be outputted verbatim without encoding
+                    val hex = ("" + iter.nextChar() + iter.nextChar()).toInt(16)
+                    (0x8000 + hex).toChar()
+                }
                 else -> throw SyntaxError("invalid escape char in string: \\$ec", position)
             })
         } else {

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

@@ -39,16 +39,20 @@ enum class DataType {
     infix fun isAssignableTo(targetTypes: Set<DataType>) = targetTypes.any { this isAssignableTo it }
 
     infix fun largerThan(other: DataType) =
-            when(this) {
-                in ByteDatatypes -> false
-                in WordDatatypes -> other in ByteDatatypes
+            when {
+                this == other -> false
+                this in ByteDatatypes -> false
+                this in WordDatatypes -> other in ByteDatatypes
+                this==STR && other==UWORD || this==UWORD && other==STR -> false
                 else -> true
             }
 
     infix fun equalsSize(other: DataType) =
-            when(this) {
-                in ByteDatatypes -> other in ByteDatatypes
-                in WordDatatypes -> other in WordDatatypes
+            when {
+                this == other -> true
+                this in ByteDatatypes -> other in ByteDatatypes
+                this in WordDatatypes -> other in WordDatatypes
+                this==STR && other==UWORD || this==UWORD && other==STR -> true
                 else -> false
             }
 

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

@@ -3,6 +3,7 @@ package prog8.ast.base
 import prog8.ast.Module
 import prog8.ast.Program
 import prog8.ast.processing.*
+import prog8.ast.statements.Directive
 import prog8.compiler.CompilationOptions
 import prog8.compiler.BeforeAsmGenerationAstChanger
 
@@ -18,8 +19,8 @@ internal fun Program.processAstBeforeAsmGeneration(errors: ErrorReporter) {
     fixer.applyModifications()
 }
 
-internal fun Program.reorderStatements() {
-    val reorder = StatementReorderer(this)
+internal fun Program.reorderStatements(errors: ErrorReporter) {
+    val reorder = StatementReorderer(this, errors)
     reorder.visit(this)
     reorder.applyModifications()
 }
@@ -56,6 +57,9 @@ internal fun Program.checkIdentifiers(errors: ErrorReporter) {
         val transforms = AstVariousTransforms(this)
         transforms.visit(this)
         transforms.applyModifications()
+        val lit2decl = LiteralsToAutoVars(this)
+        lit2decl.visit(this)
+        lit2decl.applyModifications()
     }
 
     if (modules.map { it.name }.toSet().size != modules.size) {
@@ -68,3 +72,37 @@ internal fun Program.variousCleanups() {
     process.visit(this)
     process.applyModifications()
 }
+
+internal fun Program.moveMainAndStartToFirst() {
+    // the module containing the program entrypoint is moved to the first in the sequence.
+    // the "main" block containing the entrypoint is moved to the top in there,
+    // and finally the entrypoint subroutine "start" itself is moved to the top in that block.
+
+    val directives = modules[0].statements.filterIsInstance<Directive>()
+    val start = this.entrypoint()
+    if(start!=null) {
+        val mod = start.definingModule()
+        val block = start.definingBlock()
+        if(!modules.remove(mod))
+            throw FatalAstException("module wrong")
+        modules.add(0, mod)
+        mod.remove(block)
+        var afterDirective = mod.statements.indexOfFirst { it !is Directive }
+        if(afterDirective<0)
+            mod.statements.add(block)
+        else
+            mod.statements.add(afterDirective, block)
+        block.remove(start)
+        afterDirective = block.statements.indexOfFirst { it !is Directive }
+        if(afterDirective<0)
+            block.statements.add(start)
+        else
+            block.statements.add(afterDirective, start)
+
+        // overwrite the directives in the module containing the entrypoint
+        for(directive in directives) {
+            modules[0].statements.removeAll { it is Directive && it.directive == directive.directive }
+            modules[0].statements.add(0, directive)
+        }
+    }
+}

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

@@ -872,6 +872,12 @@ class FunctionCall(override var target: IdentifierReference,
                     return InferredTypes.void()     // no return value
                 if(stmt.returntypes.size==1)
                     return InferredTypes.knownFor(stmt.returntypes[0])
+
+                // multiple return values. Can occur for asmsub routines. If there is exactly one register return value, take that.
+                val numRegisterReturns = stmt.asmReturnvaluesRegisters.count { it.registerOrPair!=null }
+                if(numRegisterReturns==1)
+                    return InferredTypes.InferredType.known(DataType.UBYTE)
+
                 return InferredTypes.unknown()     // has multiple return types... so not a single resulting datatype possible
             }
             else -> return InferredTypes.unknown()

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

@@ -346,17 +346,15 @@ internal class AstChecker(private val program: Program,
     }
 
     override fun visit(assignment: Assignment) {
-        // assigning from a functioncall COULD return multiple values (from an asm subroutine)
         if(assignment.value is FunctionCall) {
             val stmt = (assignment.value as FunctionCall).target.targetStatement(program.namespace)
-            if (stmt is Subroutine && stmt.isAsmSubroutine) {
-                if(stmt.returntypes.size>1)
-                    errors.err("It's not possible to store the multiple results of this asmsub call; you should use a small block of custom inline assembly for this.", assignment.value.position)
-                else {
-                    val idt = assignment.target.inferType(program, assignment)
-                    if(!idt.isKnown || stmt.returntypes.single()!=idt.typeOrElse(DataType.BYTE)) {
-                         errors.err("return type mismatch", assignment.value.position)
-                    }
+            if (stmt is Subroutine) {
+                val idt = assignment.target.inferType(program, assignment)
+                if(!idt.isKnown) {
+                     errors.err("return type mismatch", assignment.value.position)
+                }
+                if(stmt.returntypes.size <= 1 && stmt.returntypes.single()!=idt.typeOrElse(DataType.BYTE)) {
+                    errors.err("return type mismatch", assignment.value.position)
                 }
             }
         }
@@ -386,7 +384,8 @@ internal class AstChecker(private val program: Program,
         }
 
         val targetDt = assignment.target.inferType(program, assignment)
-        if(assignment.value.inferType(program) != targetDt) {
+        val valueDt = assignment.value.inferType(program)
+        if(valueDt.isKnown && valueDt != targetDt) {
             if(targetDt.typeOrElse(DataType.STRUCT) in IterableDatatypes)
                 errors.err("cannot assign value to string or array", assignment.value.position)
             else
@@ -446,12 +445,8 @@ internal class AstChecker(private val program: Program,
                     checkValueTypeAndRange(targetDatatype.typeOrElse(DataType.BYTE), constVal)
                 } else {
                     val sourceDatatype = assignment.value.inferType(program)
-                    if (!sourceDatatype.isKnown) {
-                        if (assignment.value is FunctionCall) {
-                            val targetStmt = (assignment.value as FunctionCall).target.targetStatement(program.namespace)
-                            if (targetStmt != null)
-                                errors.err("function call doesn't return a suitable value to use in assignment", assignment.value.position)
-                        } else
+                    if (sourceDatatype.isUnknown) {
+                        if (assignment.value !is FunctionCall)
                             errors.err("assignment value is invalid or has no proper datatype", assignment.value.position)
                     } else {
                         checkAssignmentCompatible(targetDatatype.typeOrElse(DataType.BYTE), assignTarget,
@@ -632,6 +627,14 @@ internal class AstChecker(private val program: Program,
             }
         }
 
+        // string assignment is not supported in a vard
+        if(decl.datatype==DataType.STR) {
+            if(decl.value==null)
+                err("string var must be initialized with a string literal")
+            else if (decl.type==VarDeclType.VAR && decl.value !is StringLiteralValue)
+                err("string var can only be initialized with a string literal")
+        }
+
         super.visit(decl)
     }
 
@@ -753,8 +756,13 @@ internal class AstChecker(private val program: Program,
             return e is StringLiteralValue
         }
 
-        if(!array.value.all { it is NumericLiteralValue || it is AddressOf || isPassByReferenceElement(it) })
-            errors.err("array literal contains invalid types", array.position)
+        if(array.parent is VarDecl) {
+            if (!array.value.all { it is NumericLiteralValue || it is AddressOf || isPassByReferenceElement(it) })
+                errors.err("array literal for variable initialization contains invalid types", array.position)
+        } else if(array.parent is ForLoop) {
+            if (!array.value.all { it.constValue(program) != null })
+                errors.err("array literal for iteration must contain constants. Try using a separate array variable instead?", array.position)
+        }
 
         super.visit(array)
     }
@@ -783,6 +791,8 @@ internal class AstChecker(private val program: Program,
     }
 
     override fun visit(expr: BinaryExpression) {
+        super.visit(expr)
+
         val leftIDt = expr.left.inferType(program)
         val rightIDt = expr.right.inferType(program)
         if(!leftIDt.isKnown || !rightIDt.isKnown)
@@ -822,13 +832,12 @@ internal class AstChecker(private val program: Program,
             }
         }
 
-        if(leftDt !in NumericDatatypes)
-            errors.err("left operand is not numeric", expr.left.position)
-        if(rightDt!in NumericDatatypes)
-            errors.err("right operand is not numeric", expr.right.position)
+        if(leftDt !in NumericDatatypes && leftDt != DataType.STR)
+            errors.err("left operand is not numeric or str", expr.left.position)
+        if(rightDt!in NumericDatatypes && rightDt != DataType.STR)
+            errors.err("right operand is not numeric or str", expr.right.position)
         if(leftDt!=rightDt)
             errors.err("left and right operands aren't the same type", expr.left.position)
-        super.visit(expr)
     }
 
     override fun visit(typecast: TypecastExpression) {
@@ -888,7 +897,29 @@ internal class AstChecker(private val program: Program,
 
         val error = VerifyFunctionArgTypes.checkTypes(functionCall, functionCall.definingScope(), program)
         if(error!=null)
-            errors.err(error, functionCall.args.first().position)
+            errors.err(error, functionCall.position)
+
+        // check the functions that return multiple returnvalues.
+        val stmt = functionCall.target.targetStatement(program.namespace)
+        if (stmt is Subroutine) {
+            if (stmt.returntypes.size > 1) {
+                // Currently, it's only possible to handle ONE (or zero) return values from a subroutine.
+                // asmsub routines can have multiple return values, for instance in 2 different registers.
+                // It's not (yet) possible to handle these multiple return values because assignments
+                // are only to a single unique target at the same time.
+                //   EXCEPTION:
+                // if the asmsub returns multiple values and one of them is via a status register bit,
+                // it *is* possible to handle them by just actually assigning the register value and
+                // dealing with the status bit as just being that, the status bit after the call.
+                val (returnRegisters, returnStatusflags) = stmt.asmReturnvaluesRegisters.partition { rr -> rr.registerOrPair != null }
+                if (returnRegisters.isEmpty() || returnRegisters.size == 1) {
+                    if (returnStatusflags.any())
+                        errors.warn("this asmsub also has one or more return 'values' in one of the status flags", functionCall.position)
+                } else {
+                    errors.err("It's not possible to store the multiple result values of this asmsub call; you should use a small block of custom inline assembly for this.", functionCall.position)
+                }
+            }
+        }
 
         super.visit(functionCall)
     }

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

@@ -143,8 +143,8 @@ internal class AstIdentifiersChecker(private val program: Program, private val e
     }
 
     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)
+        if (string.value.length > 255)
+            errors.err("string literal length max is 255", string.position)
 
         super.visit(string)
     }

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

@@ -47,78 +47,59 @@ internal class AstVariousTransforms(private val program: Program) : AstWalker()
         return noModifications
     }
 
-    override fun before(expr: BinaryExpression, parent: Node): Iterable<IAstModification> {
-        when {
-            expr.left is StringLiteralValue ->
-                return listOf(IAstModification.ReplaceNode(
-                        expr,
-                        processBinaryExprWithString(expr.left as StringLiteralValue, expr.right, expr),
-                        parent
-                ))
-            expr.right is StringLiteralValue ->
-                return listOf(IAstModification.ReplaceNode(
-                        expr,
-                        processBinaryExprWithString(expr.right as StringLiteralValue, expr.left, expr),
-                        parent
-                ))
+    override fun after(expr: BinaryExpression, parent: Node): Iterable<IAstModification> {
+        val leftStr = expr.left as? StringLiteralValue
+        val rightStr = expr.right as? StringLiteralValue
+        if(expr.operator == "+") {
+            val concatenatedString = concatString(expr)
+            if(concatenatedString!=null)
+                return listOf(IAstModification.ReplaceNode(expr, concatenatedString, parent))
         }
-
-        return noModifications
-    }
-
-    override fun after(string: StringLiteralValue, parent: Node): Iterable<IAstModification> {
-        if(string.parent !is VarDecl) {
-            // replace the literal string by a identifier reference to a new local vardecl
-            val vardecl = VarDecl.createAuto(string)
-            val identifier = IdentifierReference(listOf(vardecl.name), vardecl.position)
-            return listOf(
-                    IAstModification.ReplaceNode(string, identifier, parent),
-                    IAstModification.InsertFirst(vardecl, string.definingScope() as Node)
-            )
-        }
-        return noModifications
-    }
-
-    override fun after(array: ArrayLiteralValue, parent: Node): Iterable<IAstModification> {
-        val vardecl = array.parent as? VarDecl
-        if(vardecl!=null) {
-            // adjust the datatype of the array (to an educated guess)
-            val arrayDt = array.type
-            if(!arrayDt.istype(vardecl.datatype)) {
-                val cast = array.cast(vardecl.datatype)
-                if (cast != null && cast!=array)
-                    return listOf(IAstModification.ReplaceNode(vardecl.value!!, cast, vardecl))
+        else if(expr.operator == "*") {
+            if (leftStr!=null) {
+                val amount = expr.right.constValue(program)
+                if(amount!=null) {
+                    val string = leftStr.value.repeat(amount.number.toInt())
+                    val strval = StringLiteralValue(string, leftStr.altEncoding, expr.position)
+                    return listOf(IAstModification.ReplaceNode(expr, strval, parent))
+                }
             }
-        } else {
-            val arrayDt = array.guessDatatype(program)
-            if(arrayDt.isKnown) {
-                // this array literal is part of an expression, turn it into an identifier reference
-                val litval2 = array.cast(arrayDt.typeOrElse(DataType.STRUCT))
-                if(litval2!=null && litval2!=array) {
-                    val vardecl2 = VarDecl.createAuto(litval2)
-                    val identifier = IdentifierReference(listOf(vardecl2.name), vardecl2.position)
-                    return listOf(
-                            IAstModification.ReplaceNode(array, identifier, parent),
-                            IAstModification.InsertFirst(vardecl2, array.definingScope() as Node)
-                    )
+            else if (rightStr!=null) {
+                val amount = expr.right.constValue(program)
+                if(amount!=null) {
+                    val string = rightStr.value.repeat(amount.number.toInt())
+                    val strval = StringLiteralValue(string, rightStr.altEncoding, expr.position)
+                    return listOf(IAstModification.ReplaceNode(expr, strval, parent))
                 }
             }
         }
+
         return noModifications
     }
 
-    private fun processBinaryExprWithString(string: StringLiteralValue, operand: Expression, expr: BinaryExpression): Expression {
-        val constvalue = operand.constValue(program)
-        if(constvalue!=null) {
-            if (expr.operator == "*") {
-                // repeat a string a number of times
-                return StringLiteralValue(string.value.repeat(constvalue.number.toInt()), string.altEncoding, expr.position)
+    private fun concatString(expr: BinaryExpression): StringLiteralValue? {
+        val rightStrval = expr.right as? StringLiteralValue
+        val leftStrval = expr.left as? StringLiteralValue
+        return when {
+            expr.operator!="+" -> null
+            expr.left is BinaryExpression && rightStrval!=null -> {
+                val subStrVal = concatString(expr.left as BinaryExpression)
+                if(subStrVal==null)
+                    null
+                else
+                    StringLiteralValue("${subStrVal.value}${rightStrval.value}", subStrVal.altEncoding, rightStrval.position)
             }
+            expr.right is BinaryExpression && leftStrval!=null -> {
+                val subStrVal = concatString(expr.right as BinaryExpression)
+                if(subStrVal==null)
+                    null
+                else
+                    StringLiteralValue("${leftStrval.value}${subStrVal.value}", subStrVal.altEncoding, leftStrval.position)
+            }
+            leftStrval!=null && rightStrval!=null -> {
+                StringLiteralValue("${leftStrval.value}${rightStrval.value}", leftStrval.altEncoding, leftStrval.position)
+            }
+            else -> null
         }
-        if(expr.operator == "+" && operand is StringLiteralValue) {
-            // concatenate two strings
-            return StringLiteralValue("${string.value}${operand.value}", string.altEncoding, expr.position)
-        }
-        return expr
     }
 }

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

@@ -0,0 +1,53 @@
+package prog8.ast.processing
+
+import prog8.ast.Node
+import prog8.ast.Program
+import prog8.ast.base.*
+import prog8.ast.expressions.*
+import prog8.ast.statements.*
+
+
+internal class LiteralsToAutoVars(private val program: Program) : AstWalker() {
+    private val noModifications = emptyList<IAstModification>()
+
+    override fun after(string: StringLiteralValue, parent: Node): Iterable<IAstModification> {
+        if(string.parent !is VarDecl) {
+            // replace the literal string by a identifier reference to a new local vardecl
+            val vardecl = VarDecl.createAuto(string)
+            val identifier = IdentifierReference(listOf(vardecl.name), vardecl.position)
+            return listOf(
+                    IAstModification.ReplaceNode(string, identifier, parent),
+                    IAstModification.InsertFirst(vardecl, string.definingScope() as Node)
+            )
+        }
+        return noModifications
+    }
+
+    override fun after(array: ArrayLiteralValue, parent: Node): Iterable<IAstModification> {
+        val vardecl = array.parent as? VarDecl
+        if(vardecl!=null) {
+            // adjust the datatype of the array (to an educated guess)
+            val arrayDt = array.type
+            if(!arrayDt.istype(vardecl.datatype)) {
+                val cast = array.cast(vardecl.datatype)
+                if (cast != null && cast !== array)
+                    return listOf(IAstModification.ReplaceNode(vardecl.value!!, cast, vardecl))
+            }
+        } else {
+            val arrayDt = array.guessDatatype(program)
+            if(arrayDt.isKnown) {
+                // this array literal is part of an expression, turn it into an identifier reference
+                val litval2 = array.cast(arrayDt.typeOrElse(DataType.STRUCT))
+                if(litval2!=null) {
+                    val vardecl2 = VarDecl.createAuto(litval2)
+                    val identifier = IdentifierReference(listOf(vardecl2.name), vardecl2.position)
+                    return listOf(
+                            IAstModification.ReplaceNode(array, identifier, parent),
+                            IAstModification.InsertFirst(vardecl2, array.definingScope() as Node)
+                    )
+                }
+            }
+        }
+        return noModifications
+    }
+}

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

@@ -6,7 +6,7 @@ import prog8.ast.expressions.*
 import prog8.ast.statements.*
 
 
-internal class StatementReorderer(val program: Program) : AstWalker() {
+internal class StatementReorderer(val program: Program, val errors: ErrorReporter) : AstWalker() {
     // Reorders the statements in a way the compiler needs.
     // - 'main' block must be the very first statement UNLESS it has an address set.
     // - library blocks are put last.
@@ -84,20 +84,31 @@ internal class StatementReorderer(val program: Program) : AstWalker() {
     override fun before(assignment: Assignment, parent: Node): Iterable<IAstModification> {
         val valueType = assignment.value.inferType(program)
         val targetType = assignment.target.inferType(program, assignment)
+        var assignments = emptyList<Assignment>()
+
         if(targetType.istype(DataType.STRUCT) && (valueType.istype(DataType.STRUCT) || valueType.typeOrElse(DataType.STRUCT) in ArrayDatatypes )) {
-            val assignments = if (assignment.value is ArrayLiteralValue) {
-                flattenStructAssignmentFromStructLiteral(assignment, program)    //  'structvar = [ ..... ] '
+            assignments = if (assignment.value is ArrayLiteralValue) {
+                flattenStructAssignmentFromStructLiteral(assignment)    //  'structvar = [ ..... ] '
             } else {
-                flattenStructAssignmentFromIdentifier(assignment, program)    //   'structvar1 = structvar2'
+                flattenStructAssignmentFromIdentifier(assignment)    //   'structvar1 = structvar2'
             }
-            if(assignments.isNotEmpty()) {
-                val modifications = mutableListOf<IAstModification>()
-                assignments.reversed().mapTo(modifications) { IAstModification.InsertAfter(assignment, it, parent) }
-                modifications.add(IAstModification.Remove(assignment, parent))
-                return modifications
+        }
+
+        if(targetType.typeOrElse(DataType.STRUCT) in ArrayDatatypes && valueType.typeOrElse(DataType.STRUCT) in ArrayDatatypes ) {
+            assignments = if (assignment.value is ArrayLiteralValue) {
+                flattenArrayAssignmentFromArrayLiteral(assignment)    //  'arrayvar = [ ..... ] '
+            } else {
+                flattenArrayAssignmentFromIdentifier(assignment)    //   'arrayvar1 = arrayvar2'
             }
         }
 
+        if(assignments.isNotEmpty()) {
+            val modifications = mutableListOf<IAstModification>()
+            assignments.reversed().mapTo(modifications) { IAstModification.InsertAfter(assignment, it, parent) }
+            modifications.add(IAstModification.Remove(assignment, parent))
+            return modifications
+        }
+
         return noModifications
     }
 
@@ -150,15 +161,69 @@ internal class StatementReorderer(val program: Program) : AstWalker() {
         return noModifications
     }
 
-    private fun flattenStructAssignmentFromStructLiteral(structAssignment: Assignment, program: Program): List<Assignment> {
+    private fun flattenArrayAssignmentFromArrayLiteral(assign: Assignment): List<Assignment> {
+        // TODO use a pointer loop instead of individual assignments
+
+        val identifier = assign.target.identifier!!
+        val targetVar = identifier.targetVarDecl(program.namespace)!!
+
+        val alv = assign.value as? ArrayLiteralValue
+        if(targetVar.arraysize==null) {
+            errors.err("array has no defined size", identifier.position)
+            return emptyList()
+        }
+
+        if(alv==null || alv.value.size != targetVar.arraysize!!.constIndex()) {
+            errors.err("element count mismatch", assign.position)
+            return emptyList()
+        }
+
+        return alv.value.withIndex().map { (index, value)->
+            val idx = ArrayIndexedExpression(identifier, ArrayIndex(NumericLiteralValue(DataType.UBYTE, index, assign.position), assign.position), assign.position)
+            Assignment(AssignTarget(null, idx, null, assign.position), value, value.position)
+        }
+    }
+
+    private fun flattenArrayAssignmentFromIdentifier(assign: Assignment): List<Assignment> {
+        // TODO use a pointer loop instead of individual assignments
+
+        val identifier = assign.target.identifier!!
+        val targetVar = identifier.targetVarDecl(program.namespace)!!
+
+        val sourceIdent = assign.value as IdentifierReference
+        val sourceVar = sourceIdent.targetVarDecl(program.namespace)!!
+        if(!sourceVar.isArray) {
+            errors.err("value must be an array",  sourceIdent.position)
+            return emptyList()
+        }
+        if(targetVar.arraysize==null) {
+            errors.err("array has no defined size", identifier.position)
+            return emptyList()
+        }
+
+        val alv = sourceVar.value as? ArrayLiteralValue
+        if(alv==null || alv.value.size != targetVar.arraysize!!.constIndex()) {
+            errors.err("element count mismatch", assign.position)
+            return emptyList()
+        }
+
+        return alv.value.withIndex().map { (index, value)->
+            val idx = ArrayIndexedExpression(identifier, ArrayIndex(NumericLiteralValue(DataType.UBYTE, index, assign.position), assign.position), assign.position)
+            Assignment(AssignTarget(null, idx, null, assign.position), value, value.position)
+        }
+    }
+
+    private fun flattenStructAssignmentFromStructLiteral(structAssignment: Assignment): 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? ArrayLiteralValue
-        if(slv==null || slv.value.size != struct.numberOfElements)
-            throw FatalAstException("element count mismatch")
+        if(slv==null || slv.value.size != struct.numberOfElements) {
+            errors.err("element count mismatch", structAssignment.position)
+            return emptyList()
+        }
 
         return struct.statements.zip(slv.value).map { (targetDecl, sourceValue) ->
             targetDecl as VarDecl
@@ -171,7 +236,8 @@ internal class StatementReorderer(val program: Program) : AstWalker() {
         }
     }
 
-    private fun flattenStructAssignmentFromIdentifier(structAssignment: Assignment, program: Program): List<Assignment> {
+    private fun flattenStructAssignmentFromIdentifier(structAssignment: Assignment): List<Assignment> {
+        // TODO use memcopy beyond a certain number of elements
         val identifier = structAssignment.target.identifier!!
         val identifierName = identifier.nameInSource.single()
         val targetVar = identifier.targetVarDecl(program.namespace)!!

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

@@ -124,10 +124,12 @@ class TypecastsAdder(val program: Program, val errors: ErrorReporter) : AstWalke
                                         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.
-                                modifications += IAstModification.ReplaceNode(
-                                        call.args[arg.second.index],
-                                        AddressOf(arg.second.value as IdentifierReference, arg.second.value.position),
-                                        call as Node)
+                                if(arg.second.value is IdentifierReference) {
+                                    modifications += IAstModification.ReplaceNode(
+                                            call.args[arg.second.index],
+                                            AddressOf(arg.second.value as IdentifierReference, arg.second.value.position),
+                                            call as Node)
+                                }
                             } else if(arg.second.value is NumericLiteralValue) {
                                 val cast = (arg.second.value as NumericLiteralValue).cast(requiredType)
                                 if(cast.isValid)

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

@@ -4,10 +4,9 @@ import prog8.ast.IFunctionCall
 import prog8.ast.INameScope
 import prog8.ast.Program
 import prog8.ast.base.DataType
+import prog8.ast.expressions.Expression
 import prog8.ast.expressions.FunctionCall
-import prog8.ast.statements.BuiltinFunctionStatementPlaceholder
-import prog8.ast.statements.FunctionCallStatement
-import prog8.ast.statements.Subroutine
+import prog8.ast.statements.*
 import prog8.compiler.CompilerException
 import prog8.functions.BuiltinFunctions
 
@@ -43,7 +42,6 @@ class VerifyFunctionArgTypes(val program: Program) : IAstVisitor {
             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 }
@@ -53,6 +51,16 @@ class VerifyFunctionArgTypes(val program: Program) : IAstVisitor {
                     val expected = paramtypes[mismatch].toString()
                     return "argument ${mismatch + 1} type mismatch, was: $actual expected: $expected"
                 }
+                if(target.isAsmSubroutine) {
+                    if(target.asmReturnvaluesRegisters.size>1) {
+                        // multiple return values will NOT work inside an expression.
+                        // they MIGHT work in a regular assignment or just a function call statement.
+                        val parent = if(call is Statement) call.parent else if(call is Expression) call.parent else null
+                        if(call !is FunctionCallStatement && parent !is Assignment && parent !is VarDecl) {
+                            return "can't use subroutine call that returns multiple return values here (try moving it into a separate assignment)"
+                        }
+                    }
+                }
             }
             else if (target is BuiltinFunctionStatementPlaceholder) {
                 val func = BuiltinFunctions.getValue(target.name)

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

@@ -57,6 +57,7 @@ class Block(override val name: String,
             val isInLibrary: Boolean,
             override val position: Position) : Statement(), INameScope {
     override lateinit var parent: Node
+    override val asmGenInfo = AsmGenInfo()
 
     override fun linkParents(parent: Node) {
         this.parent = parent
@@ -234,7 +235,8 @@ open class VarDecl(val type: VarDeclType,
     }
 
     override fun replaceChildNode(node: Node, replacement: Node) {
-        require(replacement is Expression && node===value)
+        // TODO the check that node===value is too strict sometimes, but leaving it out allows for bugs to creep through ... :( Perhaps check when adding the replace if there is already a replace on the same node?
+        require(replacement is Expression)
         value = replacement
         replacement.parent = this
     }
@@ -416,7 +418,7 @@ data class AssignTarget(var identifier: IdentifierReference?,
         }
     }
 
-    fun inferType(program: Program, stmt: Statement): InferredTypes.InferredType {
+    fun inferType(program: Program, stmt: Statement): InferredTypes.InferredType {  // TODO why does this have the extra 'stmt' scope parameter???
         if (identifier != null) {
             val symbol = program.namespace.lookup(identifier!!.nameInSource, stmt) ?: return InferredTypes.unknown()
             if (symbol is VarDecl) return InferredTypes.knownFor(symbol.datatype)
@@ -609,6 +611,7 @@ class AnonymousScope(override var statements: MutableList<Statement>,
                      override val position: Position) : INameScope, Statement() {
     override val name: String
     override lateinit var parent: Node
+    override val asmGenInfo = AsmGenInfo()
 
     companion object {
         private var sequenceNumber = 1
@@ -662,6 +665,7 @@ class Subroutine(override val name: String,
                  override val position: Position) : Statement(), INameScope {
 
     override lateinit var parent: Node
+    override val asmGenInfo = AsmGenInfo()
     val scopedname: String by lazy { makeScopedName(name) }
 
     override fun linkParents(parent: Node) {
@@ -939,6 +943,7 @@ class StructDecl(override val name: String,
                  override val position: Position): Statement(), INameScope {
 
     override lateinit var parent: Node
+    override val asmGenInfo = AsmGenInfo()
 
     override fun linkParents(parent: Node) {
         this.parent = parent

compiler/src/prog8/compiler/BeforeAsmGenerationAstChanger.kt

@@ -161,11 +161,13 @@ internal class BeforeAsmGenerationAstChanger(val program: Program, val errors: E
 
         if(sourceDt in PassByReferenceDatatypes) {
             if(typecast.type==DataType.UWORD) {
-                return listOf(IAstModification.ReplaceNode(
-                        typecast,
-                        AddressOf(typecast.expression as IdentifierReference, typecast.position),
-                        parent
-                ))
+                if(typecast.expression is IdentifierReference) {
+                    return listOf(IAstModification.ReplaceNode(
+                            typecast,
+                            AddressOf(typecast.expression as IdentifierReference, typecast.position),
+                            parent
+                    ))
+                }
             } else {
                 errors.err("cannot cast pass-by-reference value to type ${typecast.type} (only to UWORD)", typecast.position)
             }

compiler/src/prog8/compiler/Main.kt

@@ -107,9 +107,9 @@ private fun parseImports(filepath: Path, errors: ErrorReporter): Triple<Program,
     // depending on the machine and compiler options we may have to include some libraries
     CompilationTarget.instance.machine.importLibs(compilerOptions, importer, programAst)
 
-    // always import prog8lib and math
+    // always import prog8_lib and math
     importer.importLibraryModule(programAst, "math")
-    importer.importLibraryModule(programAst, "prog8lib")
+    importer.importLibraryModule(programAst, "prog8_lib")
     errors.handle()
     return Triple(programAst, compilerOptions, importedFiles)
 }
@@ -120,8 +120,6 @@ private fun determineCompilationOptions(program: Program): CompilationOptions {
             as? Directive)?.args?.single()?.name?.toUpperCase()
     val launcherType = (mainModule.statements.singleOrNull { it is Directive && it.directive == "%launcher" }
             as? Directive)?.args?.single()?.name?.toUpperCase()
-    mainModule.loadAddress = (mainModule.statements.singleOrNull { it is Directive && it.directive == "%address" }
-            as? Directive)?.args?.single()?.int ?: 0
     val zpoption: String? = (mainModule.statements.singleOrNull { it is Directive && it.directive == "%zeropage" }
             as? Directive)?.args?.single()?.name?.toUpperCase()
     val allOptions = program.modules.flatMap { it.statements }.filter { it is Directive && it.directive == "%option" }.flatMap { (it as Directive).args }.toSet()
@@ -173,7 +171,8 @@ private fun processAst(programAst: Program, errors: ErrorReporter, compilerOptio
     errors.handle()
     programAst.constantFold(errors)
     errors.handle()
-    programAst.reorderStatements()
+    programAst.reorderStatements(errors)
+    errors.handle()
     programAst.addTypecasts(errors)
     errors.handle()
     programAst.variousCleanups()
@@ -189,10 +188,11 @@ private fun optimizeAst(programAst: Program, errors: ErrorReporter) {
     while (true) {
         // keep optimizing expressions and statements until no more steps remain
         val optsDone1 = programAst.simplifyExpressions()
-        val optsDone2 = programAst.optimizeStatements(errors)
+        val optsDone2 = programAst.splitBinaryExpressions()
+        val optsDone3 = programAst.optimizeStatements(errors)
         programAst.constantFold(errors) // because simplified statements and expressions can result in more constants that can be folded away
         errors.handle()
-        if (optsDone1 + optsDone2 == 0)
+        if (optsDone1 + optsDone2 + optsDone3 == 0)
             break
     }
 
@@ -211,6 +211,7 @@ private fun postprocessAst(programAst: Program, errors: ErrorReporter, compilerO
     programAst.checkRecursion(errors)         // check if there are recursive subroutine calls
     errors.handle()
     programAst.verifyFunctionArgTypes()
+    programAst.moveMainAndStartToFirst()
 }
 
 private fun writeAssembly(programAst: Program, errors: ErrorReporter, outputDir: Path,

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

@@ -1054,11 +1054,16 @@ object Petscii {
         val lookup = if(lowercase) encodingPetsciiLowercase else encodingPetsciiUppercase
         return text.map {
             val petscii = lookup[it]
-            petscii?.toShort() ?: if(it=='\u0000')
-                0.toShort()
-            else {
-                val case = if (lowercase) "lower" else "upper"
-                throw CharConversionException("no ${case}case Petscii character for '$it' (${it.toShort()})")
+            petscii?.toShort() ?: when (it) {
+                '\u0000' -> 0.toShort()
+                in '\u8000'..'\u80ff' -> {
+                    // special case: take the lower 8 bit hex value directly
+                    (it.toInt() - 0x8000).toShort()
+                }
+                else -> {
+                    val case = if (lowercase) "lower" else "upper"
+                    throw CharConversionException("no ${case}case Petscii character for '$it' (${it.toShort()})")
+                }
             }
         }
     }
@@ -1072,11 +1077,16 @@ object Petscii {
         val lookup = if(lowercase) encodingScreencodeLowercase else encodingScreencodeUppercase
         return text.map{
             val screencode = lookup[it]
-            screencode?.toShort() ?: if(it=='\u0000')
-                0.toShort()
-            else {
-                val case = if (lowercase) "lower" else "upper"
-                throw CharConversionException("no ${case}Screencode character for '$it' (${it.toShort()})")
+            screencode?.toShort() ?: when (it) {
+                '\u0000' -> 0.toShort()
+                in '\u8000'..'\u80ff' -> {
+                    // special case: take the lower 8 bit hex value directly
+                    (it.toInt() - 0x8000).toShort()
+                }
+                else -> {
+                    val case = if (lowercase) "lower" else "upper"
+                    throw CharConversionException("no ${case}Screencode character for '$it' (${it.toShort()})")
+                }
             }
         }
     }

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

@@ -194,11 +194,10 @@ internal class AsmGen(private val program: Program,
     }
 
     private fun assignInitialValueToVar(decl: VarDecl, variableName: List<String>) {
-        val variable = IdentifierReference(variableName, decl.position)
-        variable.linkParents(decl.parent)
+        val asmName = asmVariableName(variableName)
         val asgn = AsmAssignment(
-                AsmAssignSource.fromAstSource(decl.value!!, program),
-                AsmAssignTarget(TargetStorageKind.VARIABLE, program, this, decl.datatype, variable = variable),
+                AsmAssignSource.fromAstSource(decl.value!!, program, this),
+                AsmAssignTarget(TargetStorageKind.VARIABLE, program, this, decl.datatype, decl.definingSubroutine(), variableAsmName = asmName),
                 false, decl.position)
         assignmentAsmGen.translateNormalAssignment(asgn)
     }
@@ -496,8 +495,14 @@ internal class AsmGen(private val program: Program,
         }
     }
 
+    internal fun asmSymbolName(name: String) = fixNameSymbols(name)
+    internal fun asmVariableName(name: String) = fixNameSymbols(name)
+    internal fun asmSymbolName(name: Iterable<String>) = fixNameSymbols(name.joinToString("."))
+    internal fun asmVariableName(name: Iterable<String>) = fixNameSymbols(name.joinToString("."))
+
+
     internal fun loadByteFromPointerIntoA(pointervar: IdentifierReference): Pair<Boolean, String> {
-        // returns if the pointer is already on the ZP itself or not (in which case SCRATCH_W1 is used as intermediary)
+        // returns if the pointer is already on the ZP itself or not (in the latter case SCRATCH_W1 is used as intermediary)
         val sourceName = asmVariableName(pointervar)
         val vardecl = pointervar.targetVarDecl(program.namespace)!!
         val scopedName = vardecl.makeScopedName(vardecl.name)
@@ -538,35 +543,72 @@ internal class AsmGen(private val program: Program,
         }
     }
 
-    internal fun fixNameSymbols(name: String) = name.replace("<", "prog8_").replace(">", "")     // take care of the autogenerated invalid (anon) label names
+    private  fun fixNameSymbols(name: String) = name.replace("<", "prog8_").replace(">", "")     // take care of the autogenerated invalid (anon) label names
 
+    private val saveRegisterLabels = Stack<String>()
 
-    private val saveRegisterLabels = Stack<String>();
-
-    internal fun saveRegister(register: CpuRegister) {
-        when(register) {
-            CpuRegister.A -> out("  pha")
-            CpuRegister.X -> {
-                if (CompilationTarget.instance.machine.cpu == CpuType.CPU65c02) out("  phx")
-                else out("  stx  _prog8_regsave${register.name}")
+    internal fun saveRegister(register: CpuRegister, dontUseStack: Boolean, scope: Subroutine?) {
+        if(dontUseStack) {
+            when (register) {
+                CpuRegister.A -> {
+                    out("  sta  _prog8_regsaveA")
+                    if (scope != null)
+                        scope.asmGenInfo.usedRegsaveA = true
+                }
+                CpuRegister.X -> {
+                    out("  stx  _prog8_regsaveX")
+                    if (scope != null)
+                        scope.asmGenInfo.usedRegsaveX = true
+                }
+                CpuRegister.Y -> {
+                    out("  sty  _prog8_regsaveY")
+                    if (scope != null)
+                        scope.asmGenInfo.usedRegsaveY = true
+                }
             }
-            CpuRegister.Y -> {
-                if (CompilationTarget.instance.machine.cpu == CpuType.CPU65c02) out("  phy")
-                else out("  sty  _prog8_regsave${register.name}")
+
+        } else {
+            when (register) {
+                CpuRegister.A -> out("  pha")
+                CpuRegister.X -> {
+                    if (CompilationTarget.instance.machine.cpu == CpuType.CPU65c02) out("  phx")
+                    else {
+                        out("  stx  _prog8_regsaveX")
+                        if (scope != null)
+                            scope.asmGenInfo.usedRegsaveX = true
+                    }
+                }
+                CpuRegister.Y -> {
+                    if (CompilationTarget.instance.machine.cpu == CpuType.CPU65c02) out("  phy")
+                    else {
+                        out("  sty  _prog8_regsaveY")
+                        if (scope != null)
+                            scope.asmGenInfo.usedRegsaveY = true
+                    }
+                }
             }
         }
     }
 
-    internal fun restoreRegister(register: CpuRegister) {
-        when(register) {
-            CpuRegister.A -> out("  pla")
-            CpuRegister.X -> {
-                if (CompilationTarget.instance.machine.cpu == CpuType.CPU65c02) out("  plx")
-                else out("  ldx  _prog8_regsave${register.name}")
+    internal fun restoreRegister(register: CpuRegister, dontUseStack: Boolean) {
+        if(dontUseStack) {
+            when (register) {
+                CpuRegister.A -> out("  sta  _prog8_regsaveA")
+                CpuRegister.X -> out("  ldx  _prog8_regsaveX")
+                CpuRegister.Y -> out("  ldy  _prog8_regsaveY")
             }
-            CpuRegister.Y -> {
-                if (CompilationTarget.instance.machine.cpu == CpuType.CPU65c02) out("  ply")
-                else out("  ldy  _prog8_regsave${register.name}")
+
+        } else {
+            when (register) {
+                CpuRegister.A -> out("  pla")
+                CpuRegister.X -> {
+                    if (CompilationTarget.instance.machine.cpu == CpuType.CPU65c02) out("  plx")
+                    else out("  ldx  _prog8_regsaveX")
+                }
+                CpuRegister.Y -> {
+                    if (CompilationTarget.instance.machine.cpu == CpuType.CPU65c02) out("  ply")
+                    else out("  ldy  _prog8_regsaveY")
+                }
             }
         }
     }
@@ -588,9 +630,10 @@ internal class AsmGen(private val program: Program,
                 if (builtinFunc != null) {
                     builtinFunctionsAsmGen.translateFunctioncallStatement(stmt, builtinFunc)
                 } else {
-                    functioncallAsmGen.translateFunctionCall(stmt)
-                    // discard any results from the stack:
                     val sub = stmt.target.targetSubroutine(program.namespace)!!
+                    val preserveStatusRegisterAfterCall = sub.asmReturnvaluesRegisters.any {it.statusflag!=null}
+                    functioncallAsmGen.translateFunctionCall(stmt, preserveStatusRegisterAfterCall)
+                    // discard any results from the stack:
                     val returns = sub.returntypes.zip(sub.asmReturnvaluesRegisters)
                     for ((t, reg) in returns) {
                         if (reg.stack) {
@@ -598,6 +641,8 @@ internal class AsmGen(private val program: Program,
                             else if (t == DataType.FLOAT) out("  inx |  inx |  inx")
                         }
                     }
+                    if(preserveStatusRegisterAfterCall)
+                        out("  plp\t; restore status flags from call")
                 }
             }
             is Assignment -> assignmentAsmGen.translate(stmt)
@@ -752,6 +797,7 @@ internal class AsmGen(private val program: Program,
                             CpuRegister.Y -> out("  tay")
                         }
                     }
+                    else -> throw AssemblyError("weird dt")
                 }
             }
         }
@@ -763,8 +809,8 @@ internal class AsmGen(private val program: Program,
     internal fun translateFunctioncallExpression(functionCall: FunctionCall, signature: FSignature) =
             builtinFunctionsAsmGen.translateFunctioncallExpression(functionCall, signature)
 
-    internal fun translateFunctionCall(functionCall: FunctionCall) =
-            functioncallAsmGen.translateFunctionCall(functionCall)
+    internal fun translateFunctionCall(functionCall: FunctionCall, preserveStatusRegisterAfterCall: Boolean) =
+            functioncallAsmGen.translateFunctionCall(functionCall, preserveStatusRegisterAfterCall)
 
     internal fun translateNormalAssignment(assign: AsmAssignment) =
             assignmentAsmGen.translateNormalAssignment(assign)
@@ -806,10 +852,13 @@ internal class AsmGen(private val program: Program,
             out("; statements")
             sub.statements.forEach{ translate(it) }
             out("; variables")
-            out("""
-                ; register saves
-_prog8_regsaveX     .byte  0                
-_prog8_regsaveY     .byte  0""")        // TODO only generate these bytes if they're actually used by saveRegister()
+            out("; register saves")
+            if(sub.asmGenInfo.usedRegsaveA)
+                out("_prog8_regsaveA     .byte  0")
+            if(sub.asmGenInfo.usedRegsaveX)
+                out("_prog8_regsaveX     .byte  0")
+            if(sub.asmGenInfo.usedRegsaveY)
+                out("_prog8_regsaveY     .byte  0")
             vardecls2asm(sub.statements)
             out("  .pend\n")
         }
@@ -937,7 +986,11 @@ _prog8_regsaveY     .byte  0""")        // TODO only generate these bytes if the
         // note: A/Y must have been loaded with the number of iterations already!
         val counterVar = makeLabel("repeatcounter")
         out("""
-                sta  $counterVar
+                bne  +
+                cpy  #0
+                bne  +
+                beq  $endLabel
++               sta  $counterVar
                 sty  $counterVar+1
 $repeatLabel    lda  $counterVar
                 bne  +
@@ -966,6 +1019,7 @@ $counterVar    .word  0""")
         // note: A must have been loaded with the number of iterations already!
         val counterVar = makeLabel("repeatcounter")
         out("""
+            beq  $endLabel
             sta  $counterVar
 $repeatLabel""")
         translate(body)
@@ -1169,4 +1223,40 @@ $counterVar    .byte  0""")
         val assembly = asm.assembly.trimEnd().trimStart('\n')
         assemblyLines.add(assembly)
     }
+
+    internal fun signExtendStackLsb(valueDt: DataType) {
+        // sign extend signed byte on stack to signed word
+        when(valueDt) {
+            DataType.UBYTE -> {
+                out("  lda  #0 |  sta  P8ESTACK_HI+1,x")
+            }
+            DataType.BYTE -> {
+                out("""
+                    lda  P8ESTACK_LO+1,x
+                    ora  #$7f
+                    bmi  +
+                    lda  #0
++                   sta  P8ESTACK_HI+1,x""")
+            }
+            else -> throw AssemblyError("need byte type")
+        }
+    }
+
+    internal fun signExtendVariableLsb(asmvar: String, valueDt: DataType) {
+        // sign extend signed byte in a word variable
+        when(valueDt) {
+            DataType.UBYTE -> {
+                out("  lda  #0 |  sta  $asmvar+1")
+            }
+            DataType.BYTE -> {
+                out("""
+                    lda  $asmvar+1
+                    ora  #$7f
+                    bmi  +
+                    lda  #0
++                   sta  $asmvar+1""")
+            }
+            else -> throw AssemblyError("need byte type")
+        }
+    }
 }

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

@@ -390,12 +390,22 @@ internal class BuiltinFunctionsAsmGen(private val program: Program, private val
 
     private fun funcStrlen(fcall: IFunctionCall) {
         val name = asmgen.asmVariableName(fcall.args[0] as IdentifierReference)
-        asmgen.out("""
-            lda  #<$name
-            ldy  #>$name
-            jsr  prog8_lib.strlen
-            sta  P8ESTACK_LO,x
-            dex""")
+        val type = fcall.args[0].inferType(program)
+        when {
+            type.istype(DataType.STR) -> asmgen.out("""
+                lda  #<$name
+                ldy  #>$name
+                jsr  prog8_lib.strlen
+                sta  P8ESTACK_LO,x
+                dex""")
+            type.istype(DataType.UWORD) -> asmgen.out("""
+                lda  $name
+                ldy  $name+1
+                jsr  prog8_lib.strlen
+                sta  P8ESTACK_LO,x
+                dex""")
+            else -> throw AssemblyError("strlen requires str or uword arg")
+        }
     }
 
     private fun funcSwap(fcall: IFunctionCall) {
@@ -488,9 +498,9 @@ internal class BuiltinFunctionsAsmGen(private val program: Program, private val
         // all other types of swap() calls are done via the evaluation stack
         fun targetFromExpr(expr: Expression, datatype: DataType): AsmAssignTarget {
             return when (expr) {
-                is IdentifierReference -> AsmAssignTarget(TargetStorageKind.VARIABLE, program, asmgen, datatype, variable=expr)
-                is ArrayIndexedExpression -> AsmAssignTarget(TargetStorageKind.ARRAY, program, asmgen, datatype, array = expr)
-                is DirectMemoryRead -> AsmAssignTarget(TargetStorageKind.MEMORY, program, asmgen, datatype, memory = DirectMemoryWrite(expr.addressExpression, expr.position))
+                is IdentifierReference -> AsmAssignTarget(TargetStorageKind.VARIABLE, program, asmgen, datatype, expr.definingSubroutine(), variableAsmName = asmgen.asmVariableName(expr))
+                is ArrayIndexedExpression -> AsmAssignTarget(TargetStorageKind.ARRAY, program, asmgen, datatype, expr.definingSubroutine(), array = expr)
+                is DirectMemoryRead -> AsmAssignTarget(TargetStorageKind.MEMORY, program, asmgen, datatype, expr.definingSubroutine(), memory = DirectMemoryWrite(expr.addressExpression, expr.position))
                 else -> throw AssemblyError("invalid expression object $expr")
             }
         }
@@ -499,12 +509,12 @@ internal class BuiltinFunctionsAsmGen(private val program: Program, private val
         asmgen.translateExpression(second)
         val datatype = first.inferType(program).typeOrElse(DataType.STRUCT)
         val assignFirst = AsmAssignment(
-                AsmAssignSource(SourceStorageKind.STACK, program, datatype),
+                AsmAssignSource(SourceStorageKind.STACK, program, asmgen, datatype),
                 targetFromExpr(first, datatype),
                 false, first.position
         )
         val assignSecond = AsmAssignment(
-                AsmAssignSource(SourceStorageKind.STACK, program, datatype),
+                AsmAssignSource(SourceStorageKind.STACK, program, asmgen, datatype),
                 targetFromExpr(second, datatype),
                 false, second.position
         )

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

@@ -22,7 +22,7 @@ internal class ExpressionsAsmGen(private val program: Program, private val asmge
             is DirectMemoryRead -> translateDirectMemReadExpression(expression, true)
             is NumericLiteralValue -> translateExpression(expression)
             is IdentifierReference -> translateExpression(expression)
-            is FunctionCall -> translateExpression(expression)
+            is FunctionCall -> translateFunctionCallResultOntoStack(expression)
             is ArrayLiteralValue, is StringLiteralValue -> throw AssemblyError("no asm gen for string/array literal value assignment - should have been replaced by a variable")
             is RangeExpr -> throw AssemblyError("range expression should have been changed into array values")
         }
@@ -942,14 +942,15 @@ internal class ExpressionsAsmGen(private val program: Program, private val asmge
         asmgen.out("  jsr  floats.notequal_f |  inx |  lda  P8ESTACK_LO,x |  beq  $jumpIfFalseLabel")
     }
 
-    private fun translateExpression(expression: FunctionCall) {
+    private fun translateFunctionCallResultOntoStack(expression: FunctionCall) {
         val functionName = expression.target.nameInSource.last()
         val builtinFunc = BuiltinFunctions[functionName]
         if (builtinFunc != null) {
             asmgen.translateFunctioncallExpression(expression, builtinFunc)
         } else {
             val sub = expression.target.targetSubroutine(program.namespace)!!
-            asmgen.translateFunctionCall(expression)
+            val preserveStatusRegisterAfterCall = sub.asmReturnvaluesRegisters.any {it.statusflag!=null}
+            asmgen.translateFunctionCall(expression, preserveStatusRegisterAfterCall)
             val returns = sub.returntypes.zip(sub.asmReturnvaluesRegisters)
             for ((_, reg) in returns) {
                 if (!reg.stack) {
@@ -992,11 +993,11 @@ internal class ExpressionsAsmGen(private val program: Program, private val asmge
         }
     }
 
-    private fun translateExpression(expr: TypecastExpression) {
-        translateExpression(expr.expression)
-        when(expr.expression.inferType(program).typeOrElse(DataType.STRUCT)) {
+    private fun translateExpression(typecast: TypecastExpression) {
+        translateExpression(typecast.expression)
+        when(typecast.expression.inferType(program).typeOrElse(DataType.STRUCT)) {
             DataType.UBYTE -> {
-                when(expr.type) {
+                when(typecast.type) {
                     DataType.UBYTE, DataType.BYTE -> {}
                     DataType.UWORD, DataType.WORD -> {
                         if(CompilationTarget.instance.machine.cpu==CpuType.CPU65c02)
@@ -1010,24 +1011,16 @@ internal class ExpressionsAsmGen(private val program: Program, private val asmge
                 }
             }
             DataType.BYTE -> {
-                when(expr.type) {
+                when(typecast.type) {
                     DataType.UBYTE, DataType.BYTE -> {}
-                    DataType.UWORD, DataType.WORD -> {
-                        // sign extend
-                        asmgen.out("""
-                            lda  P8ESTACK_LO+1,x
-                            ora  #$7f
-                            bmi  +
-                            lda  #0
-+                           sta  P8ESTACK_HI+1,x""")
-                    }
+                    DataType.UWORD, DataType.WORD -> asmgen.signExtendStackLsb(DataType.BYTE)
                     DataType.FLOAT -> asmgen.out(" jsr  floats.stack_b2float")
                     in PassByReferenceDatatypes -> throw AssemblyError("cannot cast to a pass-by-reference datatype")
                     else -> throw AssemblyError("weird type")
                 }
             }
             DataType.UWORD -> {
-                when(expr.type) {
+                when(typecast.type) {
                     DataType.BYTE, DataType.UBYTE -> {}
                     DataType.WORD, DataType.UWORD -> {}
                     DataType.FLOAT -> asmgen.out(" jsr  floats.stack_uw2float")
@@ -1036,7 +1029,7 @@ internal class ExpressionsAsmGen(private val program: Program, private val asmge
                 }
             }
             DataType.WORD -> {
-                when(expr.type) {
+                when(typecast.type) {
                     DataType.BYTE, DataType.UBYTE -> {}
                     DataType.WORD, DataType.UWORD -> {}
                     DataType.FLOAT -> asmgen.out(" jsr  floats.stack_w2float")
@@ -1045,7 +1038,7 @@ internal class ExpressionsAsmGen(private val program: Program, private val asmge
                 }
             }
             DataType.FLOAT -> {
-                when(expr.type) {
+                when(typecast.type) {
                     DataType.UBYTE -> asmgen.out(" jsr  floats.stack_float2uw")
                     DataType.BYTE -> asmgen.out(" jsr  floats.stack_float2w")
                     DataType.UWORD -> asmgen.out(" jsr  floats.stack_float2uw")
@@ -1055,6 +1048,10 @@ internal class ExpressionsAsmGen(private val program: Program, private val asmge
                     else -> throw AssemblyError("weird type")
                 }
             }
+            DataType.STR -> {
+                if (typecast.type != DataType.UWORD && typecast.type == DataType.STR)
+                    throw AssemblyError("cannot typecast a string into another incompatitble type")
+            }
             in PassByReferenceDatatypes -> throw AssemblyError("cannot cast pass-by-reference value into another type")
             else -> throw AssemblyError("weird type")
         }

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

@@ -610,8 +610,8 @@ $endLabel""")
     }
 
     private fun assignLoopvar(stmt: ForLoop, range: RangeExpr) {
-        val target = AsmAssignTarget(TargetStorageKind.VARIABLE, program, asmgen, stmt.loopVarDt(program).typeOrElse(DataType.STRUCT), variable=stmt.loopVar)
-        val src = AsmAssignSource.fromAstSource(range.from, program).adjustDataTypeToTarget(target)
+        val target = AsmAssignTarget(TargetStorageKind.VARIABLE, program, asmgen, stmt.loopVarDt(program).typeOrElse(DataType.STRUCT), stmt.definingSubroutine(), variableAsmName=asmgen.asmVariableName(stmt.loopVar))
+        val src = AsmAssignSource.fromAstSource(range.from, program, asmgen).adjustSignedUnsigned(target)
         val assign = AsmAssignment(src, target, false, range.position)
         asmgen.translateNormalAssignment(assign)
     }

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

@@ -1,6 +1,7 @@
 package prog8.compiler.target.c64.codegen
 
 import prog8.ast.IFunctionCall
+import prog8.ast.Node
 import prog8.ast.Program
 import prog8.ast.base.*
 import prog8.ast.expressions.*
@@ -13,13 +14,13 @@ import prog8.compiler.target.c64.codegen.assignment.*
 
 internal class FunctionCallAsmGen(private val program: Program, private val asmgen: AsmGen) {
 
-    internal fun translateFunctionCall(stmt: IFunctionCall) {
+    internal fun translateFunctionCall(stmt: IFunctionCall, preserveStatusRegisterAfterCall: Boolean) {
         // 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 = CpuRegister.X in sub.asmClobbers || sub.regXasResult() || sub.regXasParam()
         if(saveX)
-            asmgen.saveRegister(CpuRegister.X)
+            asmgen.saveRegister(CpuRegister.X, preserveStatusRegisterAfterCall, (stmt as Node).definingSubroutine())
 
         val subName = asmgen.asmSymbolName(stmt.target)
         if(stmt.args.isNotEmpty()) {
@@ -57,8 +58,14 @@ internal class FunctionCallAsmGen(private val program: Program, private val asmg
         }
         asmgen.out("  jsr  $subName")
 
+        if(preserveStatusRegisterAfterCall) {
+            asmgen.out("  php\t; save status flags from call")
+            // note: the containing statement (such as the FunctionCallStatement or the Assignment or the Expression)
+            //       must take care of popping this value again at the end!
+        }
+
         if(saveX)
-            asmgen.restoreRegister(CpuRegister.X)
+            asmgen.restoreRegister(CpuRegister.X, preserveStatusRegisterAfterCall)
     }
 
     private fun registerArgsViaStackEvaluation(stmt: IFunctionCall, sub: Subroutine) {
@@ -148,11 +155,9 @@ internal class FunctionCallAsmGen(private val program: Program, private val asmg
         if(!isArgumentTypeCompatible(valueDt, parameter.value.type))
             throw AssemblyError("argument type incompatible")
 
-        val scopedParamVar = (sub.scopedname+"."+parameter.value.name).split(".")
-        val identifier = IdentifierReference(scopedParamVar, sub.position)
-        identifier.linkParents(value.parent)
-        val tgt = AsmAssignTarget(TargetStorageKind.VARIABLE, program, asmgen, parameter.value.type, variable = identifier)
-        val source = AsmAssignSource.fromAstSource(value, program).adjustDataTypeToTarget(tgt)
+        val varName = asmgen.asmVariableName(sub.scopedname+"."+parameter.value.name)
+        val tgt = AsmAssignTarget(TargetStorageKind.VARIABLE, program, asmgen, parameter.value.type, sub, variableAsmName = varName)
+        val source = AsmAssignSource.fromAstSource(value, program, asmgen).adjustSignedUnsigned(tgt)
         val asgn = AsmAssignment(source, tgt, false, Position.DUMMY)
         asmgen.translateNormalAssignment(asgn)
     }
@@ -170,13 +175,22 @@ internal class FunctionCallAsmGen(private val program: Program, private val asmg
         val statusflag = paramRegister.statusflag
         val register = paramRegister.registerOrPair
         val stack = paramRegister.stack
+        val requiredDt = parameter.value.type
+        if(requiredDt!=valueDt) {
+            if(valueDt largerThan requiredDt)
+                throw AssemblyError("can only convert byte values to word param types")
+        }
         when {
             stack -> {
                 // push arg onto the stack
                 // note: argument order is reversed (first argument will be deepest on the stack)
                 asmgen.translateExpression(value)
+                if(requiredDt!=valueDt)
+                    asmgen.signExtendStackLsb(valueDt)
             }
             statusflag!=null -> {
+                if(requiredDt!=valueDt)
+                    throw AssemblyError("for statusflag, byte value is required")
                 if (statusflag == Statusflag.Pc) {
                     // this param needs to be set last, right before the jsr
                     // for now, this is already enforced on the subroutine definition by the Ast Checker
@@ -216,15 +230,30 @@ internal class FunctionCallAsmGen(private val program: Program, private val asmg
             }
             else -> {
                 // via register or register pair
-                val target = AsmAssignTarget.fromRegisters(register!!, program, asmgen)
-                val src = if(valueDt in PassByReferenceDatatypes) {
-                    val addr = AddressOf(value as IdentifierReference, Position.DUMMY)
-                    AsmAssignSource.fromAstSource(addr, program).adjustDataTypeToTarget(target)
-                } else {
-                    AsmAssignSource.fromAstSource(value, program).adjustDataTypeToTarget(target)
+                val target = AsmAssignTarget.fromRegisters(register!!, sub, program, asmgen)
+                if(requiredDt largerThan valueDt) {
+                    // we need to sign extend the source, do this via temporary word variable
+                    val scratchVar = asmgen.asmVariableName("P8ZP_SCRATCH_W1")
+                    val scratchTarget = AsmAssignTarget(TargetStorageKind.VARIABLE, program, asmgen, DataType.UBYTE, sub, scratchVar)
+                    val source = AsmAssignSource.fromAstSource(value, program, asmgen)
+                    asmgen.translateNormalAssignment(AsmAssignment(source, scratchTarget, false, value.position))
+                    asmgen.signExtendVariableLsb(scratchVar, valueDt)
+                    val src = AsmAssignSource(SourceStorageKind.VARIABLE, program, asmgen, DataType.UWORD, scratchVar)
+                    asmgen.translateNormalAssignment(AsmAssignment(src, target, false, Position.DUMMY))
+                }
+                else {
+                    val src = if(valueDt in PassByReferenceDatatypes) {
+                        if(value is IdentifierReference) {
+                            val addr = AddressOf(value, Position.DUMMY)
+                            AsmAssignSource.fromAstSource(addr, program, asmgen).adjustSignedUnsigned(target)
+                        } else {
+                            AsmAssignSource.fromAstSource(value, program, asmgen).adjustSignedUnsigned(target)
+                        }
+                    } else {
+                        AsmAssignSource.fromAstSource(value, program, asmgen).adjustSignedUnsigned(target)
+                    }
+                    asmgen.translateNormalAssignment(AsmAssignment(src, target, false, Position.DUMMY))
                 }
-
-                asmgen.translateNormalAssignment(AsmAssignment(src, target, false, Position.DUMMY))
             }
         }
     }

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

@@ -15,6 +15,7 @@ internal class PostIncrDecrAsmGen(private val program: Program, private val asmg
         val targetIdent = stmt.target.identifier
         val targetMemory = stmt.target.memoryAddress
         val targetArrayIdx = stmt.target.arrayindexed
+        val scope = stmt.definingSubroutine()
         when {
             targetIdent!=null -> {
                 val what = asmgen.asmVariableName(targetIdent)
@@ -97,7 +98,7 @@ internal class PostIncrDecrAsmGen(private val program: Program, private val asmg
                     }
                     else -> {
                         asmgen.loadScaledArrayIndexIntoRegister(targetArrayIdx, elementDt, CpuRegister.A)
-                        asmgen.saveRegister(CpuRegister.X)
+                        asmgen.saveRegister(CpuRegister.X, false, scope)
                         asmgen.out("  tax")
                         when(elementDt) {
                             in ByteDatatypes -> {
@@ -125,7 +126,7 @@ internal class PostIncrDecrAsmGen(private val program: Program, private val asmg
                             }
                             else -> throw AssemblyError("weird array elt dt")
                         }
-                        asmgen.restoreRegister(CpuRegister.X)
+                        asmgen.restoreRegister(CpuRegister.X, false)
                     }
                 }
             }

compiler/src/prog8/compiler/target/c64/codegen/assignment/AsmAssignment.kt

@@ -1,11 +1,13 @@
 package prog8.compiler.target.c64.codegen.assignment
 
+import prog8.ast.INameScope
 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.DirectMemoryWrite
+import prog8.ast.statements.Subroutine
 import prog8.compiler.AssemblyError
 import prog8.compiler.target.c64.codegen.AsmGen
 
@@ -29,10 +31,11 @@ internal enum class SourceStorageKind {
 }
 
 internal class AsmAssignTarget(val kind: TargetStorageKind,
-                               program: Program,
-                               asmgen: AsmGen,
+                               private val program: Program,
+                               private val asmgen: AsmGen,
                                val datatype: DataType,
-                               val variable: IdentifierReference? = null,
+                               val scope: Subroutine?,
+                               private val variableAsmName: String? = null,
                                val array: ArrayIndexedExpression? = null,
                                val memory: DirectMemoryWrite? = null,
                                val register: RegisterOrPair? = null,
@@ -41,19 +44,15 @@ internal class AsmAssignTarget(val kind: TargetStorageKind,
 {
     val constMemoryAddress by lazy { memory?.addressExpression?.constValue(program)?.number?.toInt() ?: 0}
     val constArrayIndexValue by lazy { array?.arrayspec?.constIndex() }
-    val vardecl by lazy { variable!!.targetVarDecl(program.namespace)!! }
-    val asmVarname by lazy {
-        if(variable!=null)
-            asmgen.asmVariableName(variable)
+    val asmVarname: String
+        get() = if(array==null)
+            variableAsmName!!
         else
-            asmgen.asmVariableName(array!!.identifier)
-    }
+            asmgen.asmVariableName(array.identifier)
 
     lateinit var origAssign: AsmAssignment
 
     init {
-        if(variable!=null && vardecl.type == VarDeclType.CONST)
-            throw AssemblyError("can't assign to a constant")
         if(register!=null && datatype !in IntegerDatatypes)
             throw AssemblyError("register must be integer type")
     }
@@ -62,29 +61,30 @@ internal class AsmAssignTarget(val kind: TargetStorageKind,
         fun fromAstAssignment(assign: Assignment, program: Program, asmgen: AsmGen): AsmAssignTarget = with(assign.target) {
             val dt = inferType(program, assign).typeOrElse(DataType.STRUCT)
             when {
-                identifier != null -> AsmAssignTarget(TargetStorageKind.VARIABLE, program, asmgen, dt, variable=identifier, origAstTarget =  this)
-                arrayindexed != null -> AsmAssignTarget(TargetStorageKind.ARRAY, program, asmgen, dt, array = arrayindexed, origAstTarget =  this)
-                memoryAddress != null -> AsmAssignTarget(TargetStorageKind.MEMORY, program, asmgen, dt, memory =  memoryAddress, origAstTarget =  this)
+                identifier != null -> AsmAssignTarget(TargetStorageKind.VARIABLE, program, asmgen, dt, assign.definingSubroutine(), variableAsmName = asmgen.asmVariableName(identifier!!), origAstTarget =  this)
+                arrayindexed != null -> AsmAssignTarget(TargetStorageKind.ARRAY, program, asmgen, dt, assign.definingSubroutine(), array = arrayindexed, origAstTarget =  this)
+                memoryAddress != null -> AsmAssignTarget(TargetStorageKind.MEMORY, program, asmgen, dt, assign.definingSubroutine(), memory =  memoryAddress, origAstTarget =  this)
                 else -> throw AssemblyError("weird target")
             }
         }
 
-        fun fromRegisters(registers: RegisterOrPair, program: Program, asmgen: AsmGen): AsmAssignTarget =
+        fun fromRegisters(registers: RegisterOrPair, scope: Subroutine?, program: Program, asmgen: AsmGen): AsmAssignTarget =
                 when(registers) {
                     RegisterOrPair.A,
                     RegisterOrPair.X,
-                    RegisterOrPair.Y -> AsmAssignTarget(TargetStorageKind.REGISTER, program, asmgen, DataType.UBYTE, register = registers)
+                    RegisterOrPair.Y -> AsmAssignTarget(TargetStorageKind.REGISTER, program, asmgen, DataType.UBYTE, scope, register = registers)
                     RegisterOrPair.AX,
                     RegisterOrPair.AY,
-                    RegisterOrPair.XY -> AsmAssignTarget(TargetStorageKind.REGISTER, program, asmgen, DataType.UWORD, register = registers)
+                    RegisterOrPair.XY -> AsmAssignTarget(TargetStorageKind.REGISTER, program, asmgen, DataType.UWORD, scope, register = registers)
                 }
     }
 }
 
 internal class AsmAssignSource(val kind: SourceStorageKind,
                                private val program: Program,
+                               private val asmgen: AsmGen,
                                val datatype: DataType,
-                               val variable: IdentifierReference? = null,
+                               private val variableAsmName: String? = null,
                                val array: ArrayIndexedExpression? = null,
                                val memory: DirectMemoryRead? = null,
                                val register: CpuRegister? = null,
@@ -94,51 +94,70 @@ internal class AsmAssignSource(val kind: SourceStorageKind,
 {
     val constMemoryAddress by lazy { memory?.addressExpression?.constValue(program)?.number?.toInt() ?: 0}
     val constArrayIndexValue by lazy { array?.arrayspec?.constIndex() }
-    val vardecl by lazy { variable?.targetVarDecl(program.namespace)!! }
+
+    val asmVarname: String
+        get() = if(array==null)
+            variableAsmName!!
+        else
+            asmgen.asmVariableName(array.identifier)
 
     companion object {
-        fun fromAstSource(value: Expression, program: Program): AsmAssignSource {
+        fun fromAstSource(value: Expression, program: Program, asmgen: AsmGen): AsmAssignSource {
             val cv = value.constValue(program)
             if(cv!=null)
-                return AsmAssignSource(SourceStorageKind.LITERALNUMBER, program, cv.type, number = cv)
+                return AsmAssignSource(SourceStorageKind.LITERALNUMBER, program, asmgen, cv.type, number = cv)
 
             return when(value) {
-                is NumericLiteralValue -> AsmAssignSource(SourceStorageKind.LITERALNUMBER, program, value.type, number = cv)
+                is NumericLiteralValue -> AsmAssignSource(SourceStorageKind.LITERALNUMBER, program, asmgen, value.type, number = cv)
                 is StringLiteralValue -> throw AssemblyError("string literal value should not occur anymore for asm generation")
                 is ArrayLiteralValue -> throw AssemblyError("array literal value should not occur anymore for asm generation")
                 is IdentifierReference -> {
                     val dt = value.inferType(program).typeOrElse(DataType.STRUCT)
-                    AsmAssignSource(SourceStorageKind.VARIABLE, program, dt, variable = value)
+                    AsmAssignSource(SourceStorageKind.VARIABLE, program, asmgen, dt, variableAsmName = asmgen.asmVariableName(value))
                 }
                 is DirectMemoryRead -> {
-                    AsmAssignSource(SourceStorageKind.MEMORY, program, DataType.UBYTE, memory = value)
+                    AsmAssignSource(SourceStorageKind.MEMORY, program, asmgen, DataType.UBYTE, memory = value)
                 }
                 is ArrayIndexedExpression -> {
                     val dt = value.inferType(program).typeOrElse(DataType.STRUCT)
-                    AsmAssignSource(SourceStorageKind.ARRAY, program, dt, array = value)
+                    AsmAssignSource(SourceStorageKind.ARRAY, program, asmgen, dt, array = value)
                 }
                 else -> {
+                    if(value is FunctionCall) {
+                        // functioncall.
+                        val asmSub = value.target.targetStatement(program.namespace)
+                        if(asmSub is Subroutine && asmSub.isAsmSubroutine) {
+                            when (asmSub.asmReturnvaluesRegisters.count { rr -> rr.registerOrPair!=null }) {
+                                0 -> throw AssemblyError("can't translate zero return values in assignment")
+                                1 -> {
+                                    // assignment generation itself must make sure the status register is correct after the subroutine call, if status register is involved!
+                                    val reg = asmSub.asmReturnvaluesRegisters.single { rr->rr.registerOrPair!=null }.registerOrPair!!
+                                    val dt = when(reg) {
+                                        RegisterOrPair.A,
+                                        RegisterOrPair.X,
+                                        RegisterOrPair.Y -> DataType.UBYTE
+                                        RegisterOrPair.AX,
+                                        RegisterOrPair.AY,
+                                        RegisterOrPair.XY -> DataType.UWORD
+                                    }
+                                    return AsmAssignSource(SourceStorageKind.EXPRESSION, program, asmgen, dt, expression = value)
+                                }
+                                else -> throw AssemblyError("can't translate multiple return values in assignment")
+                            }
+                        }
+                    }
+
                     val dt = value.inferType(program).typeOrElse(DataType.STRUCT)
-                    AsmAssignSource(SourceStorageKind.EXPRESSION, program, dt, expression = value)
+                    return AsmAssignSource(SourceStorageKind.EXPRESSION, program, asmgen, dt, expression = value)
                 }
             }
         }
     }
 
-    fun getAstValue(): Expression = when(kind) {
-        SourceStorageKind.LITERALNUMBER -> number!!
-        SourceStorageKind.VARIABLE -> variable!!
-        SourceStorageKind.ARRAY -> array!!
-        SourceStorageKind.MEMORY -> memory!!
-        SourceStorageKind.EXPRESSION -> expression!!
-        SourceStorageKind.REGISTER -> throw AssemblyError("cannot get a register source as Ast node")
-        SourceStorageKind.STACK -> throw AssemblyError("cannot get a stack source as Ast node")
-    }
-
     fun withAdjustedDt(newType: DataType) =
-            AsmAssignSource(kind, program, newType, variable, array, memory, register, number, expression)
+            AsmAssignSource(kind, program, asmgen, newType, variableAsmName, array, memory, register, number, expression)
 
-    fun adjustDataTypeToTarget(target: AsmAssignTarget): AsmAssignSource {
+    fun adjustSignedUnsigned(target: AsmAssignTarget): AsmAssignSource {
         // allow some signed/unsigned relaxations
         if(target.datatype!=datatype) {
             if(target.datatype in ByteDatatypes && datatype in ByteDatatypes) {
@@ -160,6 +179,9 @@ internal class AsmAssignment(val source: AsmAssignSource,
 
     init {
         if(target.register !in setOf(RegisterOrPair.XY, RegisterOrPair.AX, RegisterOrPair.AY))
-            require(source.datatype.memorySize() == target.datatype.memorySize()) { "source and target datatype must be same storage class" }
+            require(source.datatype != DataType.STRUCT) { "must not be placeholder datatype" }
+            require(source.datatype.memorySize() <= target.datatype.memorySize()) {
+                "source storage size must be less or equal to target datatype storage size"
+            }
     }
 }

compiler/src/prog8/compiler/target/c64/codegen/assignment/AssignmentAsmGen.kt

@@ -18,7 +18,7 @@ internal class AssignmentAsmGen(private val program: Program, private val asmgen
 
     fun translate(assignment: Assignment) {
         val target = AsmAssignTarget.fromAstAssignment(assignment, program, asmgen)
-        val source = AsmAssignSource.fromAstSource(assignment.value, program).adjustDataTypeToTarget(target)
+        val source = AsmAssignSource.fromAstSource(assignment.value, program, asmgen).adjustSignedUnsigned(target)
 
         val assign = AsmAssignment(source, target, assignment.isAugmentable, assignment.position)
         target.origAssign = assign
@@ -34,7 +34,7 @@ internal class AssignmentAsmGen(private val program: Program, private val asmgen
             SourceStorageKind.LITERALNUMBER -> {
                 // simple case: assign a constant number
                 val num = assign.source.number!!.number
-                when (assign.source.datatype) {
+                when (assign.target.datatype) {
                     DataType.UBYTE, DataType.BYTE -> assignConstantByte(assign.target, num.toShort())
                     DataType.UWORD, DataType.WORD -> assignConstantWord(assign.target, num.toInt())
                     DataType.FLOAT -> assignConstantFloat(assign.target, num.toDouble())
@@ -43,12 +43,16 @@ internal class AssignmentAsmGen(private val program: Program, private val asmgen
             }
             SourceStorageKind.VARIABLE -> {
                 // simple case: assign from another variable
-                val variable = assign.source.variable!!
-                when (assign.source.datatype) {
+                val variable = assign.source.asmVarname!!
+                when (assign.target.datatype) {
                     DataType.UBYTE, DataType.BYTE -> assignVariableByte(assign.target, variable)
                     DataType.UWORD, DataType.WORD -> assignVariableWord(assign.target, variable)
                     DataType.FLOAT -> assignVariableFloat(assign.target, variable)
-                    in PassByReferenceDatatypes -> assignAddressOf(assign.target, variable)
+                    DataType.STR -> assignVariableString(assign.target, variable)
+                    in PassByReferenceDatatypes -> {
+                        // TODO what about when the name is a struct? name.firstStructVarName(program.namespace)
+                        assignAddressOf(assign.target, variable)
+                    }
                     else -> throw AssemblyError("unsupported assignment target type ${assign.target.datatype}")
                 }
             }
@@ -116,29 +120,45 @@ internal class AssignmentAsmGen(private val program: Program, private val asmgen
             SourceStorageKind.EXPRESSION -> {
                 val value = assign.source.expression!!
                 when(value) {
-                    is AddressOf -> assignAddressOf(assign.target, value.identifier)
+                    is AddressOf -> {
+                        val sourceName = value.identifier.firstStructVarName(program.namespace) ?: asmgen.asmVariableName(value.identifier)
+                        assignAddressOf(assign.target, sourceName)
+                    }
                     is NumericLiteralValue -> throw AssemblyError("source kind should have been literalnumber")
                     is IdentifierReference -> throw AssemblyError("source kind should have been variable")
                     is ArrayIndexedExpression -> throw AssemblyError("source kind should have been array")
                     is DirectMemoryRead -> throw AssemblyError("source kind should have been memory")
                     is TypecastExpression -> assignTypeCastedValue(assign.target, value.type, value.expression, assign)
-//                    is FunctionCall -> {
-//                        if (assign.target.kind == TargetStorageKind.STACK) {
-//                            asmgen.translateExpression(value)
-//                            assignStackValue(assign.target)
-//                        } else {
-//                            val functionName = value.target.nameInSource.last()
-//                            val builtinFunc = BuiltinFunctions[functionName]
-//                            if (builtinFunc != null) {
-//                                println("!!!!BUILTIN-FUNCCALL target=${assign.target.kind} $value") // TODO optimize certain functions?
-//                            }
-//                            asmgen.translateExpression(value)
-//                            assignStackValue(assign.target)
-//                        }
-//                    }
+                    is FunctionCall -> {
+                        if(value.target.targetSubroutine(program.namespace)?.isAsmSubroutine==true) {
+                            // handle asmsub functioncalls specifically, without shoving stuff on the estack
+                            val sub = value.target.targetSubroutine(program.namespace)!!
+                            val preserveStatusRegisterAfterCall = sub.asmReturnvaluesRegisters.any { it.statusflag != null }
+                            asmgen.translateFunctionCall(value, preserveStatusRegisterAfterCall)
+                            when((sub.asmReturnvaluesRegisters.single { it.registerOrPair!=null }).registerOrPair) {
+                                RegisterOrPair.A -> assignRegisterByte(assign.target, CpuRegister.A)
+                                RegisterOrPair.X -> assignRegisterByte(assign.target, CpuRegister.X)
+                                RegisterOrPair.Y -> assignRegisterByte(assign.target, CpuRegister.Y)
+                                RegisterOrPair.AX -> assignRegisterpairWord(assign.target, RegisterOrPair.AX)
+                                RegisterOrPair.AY -> assignRegisterpairWord(assign.target, RegisterOrPair.AY)
+                                RegisterOrPair.XY -> assignRegisterpairWord(assign.target, RegisterOrPair.XY)
+                                else -> throw AssemblyError("should be just one register byte result value")
+                            }
+                            if(preserveStatusRegisterAfterCall)
+                                asmgen.out("  plp\t; restore status flags from call")
+                        } else {
+                            // regular subroutine, return values are (for now) always done via the stack...  TODO optimize this
+                            asmgen.translateExpression(value)
+                            if(assign.target.datatype in WordDatatypes && assign.source.datatype in ByteDatatypes)
+                                asmgen.signExtendStackLsb(assign.source.datatype)
+                            assignStackValue(assign.target)
+                        }
+                    }
                     else -> {
                         // everything else just evaluate via the stack.
                         asmgen.translateExpression(value)
+                        if(assign.target.datatype in WordDatatypes && assign.source.datatype in ByteDatatypes)
+                            asmgen.signExtendStackLsb(assign.source.datatype)
                         assignStackValue(assign.target)
                     }
                 }
@@ -156,9 +176,13 @@ internal class AssignmentAsmGen(private val program: Program, private val asmgen
         val valueDt = value.inferType(program).typeOrElse(DataType.STRUCT)
         when(value) {
             is IdentifierReference -> {
-                if (valueDt == DataType.UBYTE || valueDt == DataType.BYTE) {
-                    if(targetDt in WordDatatypes) {
-                        assignVariableByteIntoWord(target, value, valueDt)
+                if(targetDt in WordDatatypes) {
+                    if(valueDt==DataType.UBYTE) {
+                        assignVariableUByteIntoWord(target, value)
+                        return
+                    }
+                    if(valueDt==DataType.BYTE) {
+                        assignVariableByteIntoWord(target, value)
                         return
                     }
                 }
@@ -221,6 +245,18 @@ internal class AssignmentAsmGen(private val program: Program, private val asmgen
                             jsr  floats.pop_float
                         """)
                     }
+                    DataType.STR -> {
+                        asmgen.out("""
+                            lda  #<${target.asmVarname}
+                            sta  P8ZP_SCRATCH_W1
+                            lda  #>${target.asmVarname}
+                            sta  P8ZP_SCRATCH_W1+1
+                            inx
+                            lda  P8ESTACK_HI,x
+                            tay
+                            lda  P8ESTACK_LO,x
+                            jsr  prog8_lib.strcpy""")
+                    }
                     else -> throw AssemblyError("weird target variable type ${target.datatype}")
                 }
             }
@@ -319,9 +355,7 @@ internal class AssignmentAsmGen(private val program: Program, private val asmgen
         }
     }
 
-    private fun assignAddressOf(target: AsmAssignTarget, name: IdentifierReference) {
-        val sourceName = name.firstStructVarName(program.namespace) ?: asmgen.fixNameSymbols(name.nameInSource.joinToString("."))
-
+    private fun assignAddressOf(target: AsmAssignTarget, sourceName: String) {
         when(target.kind) {
             TargetStorageKind.VARIABLE -> {
                 asmgen.out("""
@@ -346,19 +380,54 @@ internal class AssignmentAsmGen(private val program: Program, private val asmgen
                 }
             }
             TargetStorageKind.STACK -> {
-                val srcname = asmgen.asmVariableName(name)
                 asmgen.out("""
-                    lda  #<$srcname
+                    lda  #<$sourceName
                     sta  P8ESTACK_LO,x
-                    lda  #>$srcname
+                    lda  #>$sourceName
                     sta  P8ESTACK_HI,x
                     dex""")
             }
         }
     }
 
-    private fun assignVariableWord(target: AsmAssignTarget, variable: IdentifierReference) {
-        val sourceName = asmgen.asmVariableName(variable)
+    private fun assignVariableString(target: AsmAssignTarget, sourceName: String) {
+        when(target.kind) {
+            TargetStorageKind.VARIABLE -> {
+                when(target.datatype) {
+                    DataType.UWORD -> {
+                        asmgen.out("""
+                            lda #<$sourceName
+                            sta ${target.asmVarname}
+                            lda #>$sourceName
+                            sta ${target.asmVarname}+1
+                        """)
+                    }
+                    DataType.STR, DataType.ARRAY_UB, DataType.ARRAY_B -> {
+                        asmgen.out("""
+                            lda  #<${target.asmVarname}
+                            sta  P8ZP_SCRATCH_W1
+                            lda  #>${target.asmVarname}
+                            sta  P8ZP_SCRATCH_W1+1
+                            lda  #<$sourceName
+                            ldy  #>$sourceName
+                            jsr  prog8_lib.strcpy""")
+                    }
+                    else -> throw AssemblyError("assign string to incompatible variable type")
+                }
+            }
+            TargetStorageKind.STACK -> {
+                asmgen.out("""
+                    lda  #<$sourceName
+                    sta  P8ESTACK_LO,x
+                    lda  #>$sourceName+1
+                    sta  P8ESTACK_HI,x
+                    dex""")
+            }
+            else -> throw AssemblyError("string-assign to weird target")
+        }
+    }
+
+    private fun assignVariableWord(target: AsmAssignTarget, sourceName: String) {
         when(target.kind) {
             TargetStorageKind.VARIABLE -> {
                 asmgen.out("""
@@ -461,8 +530,7 @@ internal class AssignmentAsmGen(private val program: Program, private val asmgen
         }
     }
 
-    private fun assignVariableFloat(target: AsmAssignTarget, variable: IdentifierReference) {
-        val sourceName = asmgen.asmVariableName(variable)
+    private fun assignVariableFloat(target: AsmAssignTarget, sourceName: String) {
         when(target.kind) {
             TargetStorageKind.VARIABLE -> {
                 asmgen.out("""
@@ -496,8 +564,7 @@ internal class AssignmentAsmGen(private val program: Program, private val asmgen
         }
     }
 
-    private fun assignVariableByte(target: AsmAssignTarget, variable: IdentifierReference) {
-        val sourceName = asmgen.asmVariableName(variable)
+    private fun assignVariableByte(target: AsmAssignTarget, sourceName: String) {
         when(target.kind) {
             TargetStorageKind.VARIABLE -> {
                 asmgen.out("""
@@ -546,10 +613,68 @@ internal class AssignmentAsmGen(private val program: Program, private val asmgen
         }
     }
 
-    private fun assignVariableByteIntoWord(wordtarget: AsmAssignTarget, bytevar: IdentifierReference, valueDt: DataType) {
-        if(valueDt == DataType.BYTE)
-            TODO("sign extend byte to word")
+    private fun assignVariableByteIntoWord(wordtarget: AsmAssignTarget, bytevar: IdentifierReference) {
+        val sourceName = asmgen.asmVariableName(bytevar)
+        when (wordtarget.kind) {
+            TargetStorageKind.VARIABLE -> {
+                asmgen.out("""
+                    lda  $sourceName
+                    sta  ${wordtarget.asmVarname}
+                    ora  #$7f
+                    bmi  +
+                    lda  #0
++                   sta  ${wordtarget.asmVarname}+1
+                    """)
+            }
+            TargetStorageKind.ARRAY -> {
+                // TODO optimize slow stack evaluation for this case, see assignVariableUByteIntoWord
+                println("warning: slow stack evaluation used for sign-extend byte typecast at ${bytevar.position}")
+                asmgen.translateExpression(wordtarget.origAssign.source.expression!!)
+                assignStackValue(wordtarget)
+            }
+            TargetStorageKind.REGISTER -> {
+                when(wordtarget.register!!) {
+                    RegisterOrPair.AX -> asmgen.out("""
+                        lda  $sourceName
+                        pha
+                        ora  #$7f
+                        bmi  +
+                        ldx  #0
++                       tax
+                        pla""")
+                    RegisterOrPair.AY -> asmgen.out("""
+                        lda  $sourceName
+                        pha
+                        ora  #$7f
+                        bmi  +
+                        ldy  #0
++                       tay
+                        pla""")
+                    RegisterOrPair.XY -> asmgen.out("""
+                        lda  $sourceName
+                        tax 
+                        ora  #$7f
+                        bmi  +
+                        ldy  #0
++                       tay""")
+                    else -> throw AssemblyError("only reg pairs are words")
+                }
+            }
+            TargetStorageKind.STACK -> {
+                asmgen.out("""
+                    lda  $sourceName
+                    sta  P8ESTACK_LO,x
+                    ora  #$7f
+                    bmi  +                    
+                    lda  #0
++                   sta  P8ESTACK_HI,x
+                    dex""")
+            }
+            else -> throw AssemblyError("target type isn't word")
+        }
+    }
 
+    private fun assignVariableUByteIntoWord(wordtarget: AsmAssignTarget, bytevar: IdentifierReference) {
         val sourceName = asmgen.asmVariableName(bytevar)
         when(wordtarget.kind) {
             TargetStorageKind.VARIABLE -> {
@@ -589,13 +714,13 @@ internal class AssignmentAsmGen(private val program: Program, private val asmgen
             }
             TargetStorageKind.STACK -> {
                 asmgen.out("""
-                    lda  #$sourceName
+                    lda  $sourceName
                     sta  P8ESTACK_LO,x
                     lda  #0
                     sta  P8ESTACK_HI,x
                     dex""")
             }
-            else -> throw AssemblyError("other types aren't word")
+            else -> throw AssemblyError("target type isn't word")
         }
     }
 
@@ -628,9 +753,9 @@ internal class AssignmentAsmGen(private val program: Program, private val asmgen
                         asmgen.out(" ldy  ${asmgen.asmVariableName(index)} |  sta  ${target.asmVarname},y")
                     }
                     else -> {
-                        asmgen.saveRegister(register)
+                        asmgen.saveRegister(register, false, target.scope)
                         asmgen.translateExpression(index)
-                        asmgen.restoreRegister(register)
+                        asmgen.restoreRegister(register, false)
                         when (register) {
                             CpuRegister.A -> asmgen.out("  sta  P8ZP_SCRATCH_B1")
                             CpuRegister.X -> asmgen.out("  stx  P8ZP_SCRATCH_B1")
@@ -684,6 +809,54 @@ internal class AssignmentAsmGen(private val program: Program, private val asmgen
         }
     }
 
+    private fun assignRegisterpairWord(target: AsmAssignTarget, regs: RegisterOrPair) {
+        require(target.datatype in WordDatatypes)
+        when(target.kind) {
+            TargetStorageKind.VARIABLE -> {
+                when(regs) {
+                    RegisterOrPair.AX -> asmgen.out("  sta  ${target.asmVarname} |  stx  ${target.asmVarname}+1")
+                    RegisterOrPair.AY -> asmgen.out("  sta  ${target.asmVarname} |  sty  ${target.asmVarname}+1")
+                    RegisterOrPair.XY -> asmgen.out("  stx  ${target.asmVarname} |  sty  ${target.asmVarname}+1")
+                    else -> throw AssemblyError("expected reg pair")
+                }
+            }
+            TargetStorageKind.ARRAY -> {
+                TODO("store register pair $regs into word-array ${target.array}")
+            }
+            TargetStorageKind.REGISTER -> {
+                when(regs) {
+                    RegisterOrPair.AX -> when(target.register!!) {
+                        RegisterOrPair.AY -> { asmgen.out("  stx  P8ZP_SCRATCH_REG |  ldy  P8ZP_SCRATCH_REG") }
+                        RegisterOrPair.AX -> { }
+                        RegisterOrPair.XY -> { asmgen.out("  stx  P8ZP_SCRATCH_REG |  ldy  P8ZP_SCRATCH_REG |  tax") }
+                        else -> throw AssemblyError("expected reg pair")
+                    }
+                    RegisterOrPair.AY -> when(target.register!!) {
+                        RegisterOrPair.AY -> { }
+                        RegisterOrPair.AX -> { asmgen.out("  sty  P8ZP_SCRATCH_REG |  ldx  P8ZP_SCRATCH_REG") }
+                        RegisterOrPair.XY -> { asmgen.out("  tax") }
+                        else -> throw AssemblyError("expected reg pair")
+                    }
+                    RegisterOrPair.XY -> when(target.register!!) {
+                        RegisterOrPair.AY -> { asmgen.out("  txa") }
+                        RegisterOrPair.AX -> { asmgen.out("  txa |  sty  P8ZP_SCRATCH_REG |  ldx  P8ZP_SCRATCH_REG") }
+                        RegisterOrPair.XY -> { }
+                        else -> throw AssemblyError("expected reg pair")
+                    }
+                    else -> throw AssemblyError("expected reg pair")
+                }
+            }
+            TargetStorageKind.STACK -> {
+                when(regs) {
+                    RegisterOrPair.AY -> asmgen.out(" sta  P8ESTACK_LO,x |  sty  P8ESTACK_HI,x |  dex")
+                    RegisterOrPair.AX, RegisterOrPair.XY -> throw AssemblyError("can't use X here")
+                    else -> throw AssemblyError("expected reg pair")
+                }
+            }
+            TargetStorageKind.MEMORY -> throw AssemblyError("can't store word into memory byte")
+        }
+    }
+
     private fun assignConstantWord(target: AsmAssignTarget, word: Int) {
         when(target.kind) {
             TargetStorageKind.VARIABLE -> {
@@ -1079,9 +1252,9 @@ internal class AssignmentAsmGen(private val program: Program, private val asmgen
                 asmgen.storeByteIntoPointer(addressExpr, null)
             }
             else -> {
-                asmgen.saveRegister(register)
+                asmgen.saveRegister(register, false, memoryAddress.definingSubroutine())
                 asmgen.translateExpression(addressExpr)
-                asmgen.restoreRegister(CpuRegister.A)
+                asmgen.restoreRegister(CpuRegister.A, false)
                 asmgen.out("""
                     inx
                     ldy  P8ESTACK_LO,x

compiler/src/prog8/compiler/target/c64/codegen/assignment/AugmentableAssignmentAsmGen.kt

@@ -1,8 +1,10 @@
 package prog8.compiler.target.c64.codegen.assignment
 
+import prog8.ast.INameScope
 import prog8.ast.Program
 import prog8.ast.base.*
 import prog8.ast.expressions.*
+import prog8.ast.statements.Subroutine
 import prog8.compiler.AssemblyError
 import prog8.compiler.target.CompilationTarget
 import prog8.compiler.target.CpuType
@@ -137,13 +139,13 @@ internal class AugmentableAssignmentAsmGen(private val program: Program,
                     }
                     DataType.FLOAT -> {
                         when {
-                            valueLv != null -> inplaceModification_float_litval_to_variable(target.asmVarname, operator, valueLv.toDouble())
-                            ident != null -> inplaceModification_float_variable_to_variable(target.asmVarname, operator, ident)
+                            valueLv != null -> inplaceModification_float_litval_to_variable(target.asmVarname, operator, valueLv.toDouble(), target.scope)
+                            ident != null -> inplaceModification_float_variable_to_variable(target.asmVarname, operator, ident, target.scope)
                             value is TypecastExpression -> {
                                 if (tryRemoveRedundantCast(value, target, operator)) return
-                                inplaceModification_float_value_to_variable(target.asmVarname, operator, value)
+                                inplaceModification_float_value_to_variable(target.asmVarname, operator, value, target.scope)
                             }
-                            else -> inplaceModification_float_value_to_variable(target.asmVarname, operator, value)
+                            else -> inplaceModification_float_value_to_variable(target.asmVarname, operator, value, target.scope)
                         }
                     }
                     else -> throw AssemblyError("weird type to do in-place modification on ${target.datatype}")
@@ -222,123 +224,92 @@ internal class AugmentableAssignmentAsmGen(private val program: Program,
     private fun inplaceModification_byte_value_to_memory(pointervar: IdentifierReference, operator: String, value: Expression) {
         println("warning: slow stack evaluation used (3):  @(${pointervar.nameInSource.last()}) $operator= ${value::class.simpleName} at ${value.position}") // TODO
         asmgen.translateExpression(value)
+        val (ptrOnZp, sourceName) = asmgen.loadByteFromPointerIntoA(pointervar)
         when (operator) {
             // note: ** (power) operator requires floats.
-            "+" -> {
-                val (ptrOnZp, sourceName) = asmgen.loadByteFromPointerIntoA(pointervar)
-                asmgen.out(" clc |  adc  P8ESTACK_LO+1,x")
-                if(ptrOnZp)
-                    asmgen.out("  sta  ($sourceName),y")
-                else
-                    asmgen.out("  sta  (P8ZP_SCRATCH_W1),y")
+            "+" -> asmgen.out(" clc |  adc  P8ESTACK_LO+1,x")
+            "-" -> asmgen.out(" sec |  sbc  P8ESTACK_LO+1,x")
+            "*" -> asmgen.out("  pha |  lda  P8ESTACK_LO+1,x |  tay |  pla |  jsr  math.multiply_bytes |  ldy  #0")
+            "/" -> asmgen.out("  pha |  lda  P8ESTACK_LO+1,x |  tay |  pla |  jsr  math.divmod_ub_asm |  tya |  ldy  #0")
+            "%" -> asmgen.out("  pha |  lda  P8ESTACK_LO+1,x |  tay |  pla |  jsr  math.divmod_ub_asm |  ldy  #0")
+            "<<" -> {
+                asmgen.out("""
+                    pha
+                    lda  P8ESTACK_LO+1,x
+                    bne  +
+                    pla
+                    rts
++                   tay
+                    pla 
+-                   asl  a
+                    dey
+                    bne  -
++""")
             }
-            "-" -> {
-                val (ptrOnZp, sourceName) = asmgen.loadByteFromPointerIntoA(pointervar)
-                asmgen.out(" sec |  sbc  P8ESTACK_LO+1,x")
-                if(ptrOnZp)
-                    asmgen.out("  sta  ($sourceName),y")
-                else
-                    asmgen.out("  sta  (P8ZP_SCRATCH_W1),y")
-            }
-            "*" -> {
-                TODO("mul mem byte")// asmgen.out("  jsr  prog8_lib.mul_byte")
-            }
-            "/" -> TODO("div mem byte")// asmgen.out(if(types==DataType.UBYTE) "  jsr  prog8_lib.idiv_ub" else "  jsr  prog8_lib.idiv_b")
-            "%" -> {
-                TODO("mem byte remainder")
-//                if(types==DataType.BYTE)
-//                    throw AssemblyError("remainder of signed integers is not properly defined/implemented, use unsigned instead")
-//                asmgen.out("  jsr prog8_lib.remainder_ub")
-            }
-            "<<" -> TODO("mem ubyte asl")
-            ">>" -> TODO("mem ubyte lsr")
-            "&" -> {
-                val (ptrOnZp, sourceName) = asmgen.loadByteFromPointerIntoA(pointervar)
-                asmgen.out(" and  P8ESTACK_LO+1,x")
-                if(ptrOnZp)
-                    asmgen.out("  sta  ($sourceName),y")
-                else
-                    asmgen.out("  sta  (P8ZP_SCRATCH_W1),y")
-            }
-            "^" -> {
-                val (ptrOnZp, sourceName) = asmgen.loadByteFromPointerIntoA(pointervar)
-                asmgen.out(" eor  P8ESTACK_LO+1,x")
-                if(ptrOnZp)
-                    asmgen.out("  sta  ($sourceName),y")
-                else
-                    asmgen.out("  sta  (P8ZP_SCRATCH_W1),y")
-            }
-            "|" -> {
-                val (ptrOnZp, sourceName) = asmgen.loadByteFromPointerIntoA(pointervar)
-                asmgen.out(" ora  P8ESTACK_LO+1,x")
-                if(ptrOnZp)
-                    asmgen.out("  sta  ($sourceName),y")
-                else
-                    asmgen.out("  sta  (P8ZP_SCRATCH_W1),y")
+            ">>" -> {
+                asmgen.out("""
+                    pha
+                    lda  P8ESTACK_LO+1,x
+                    bne  +
+                    pla
+                    rts
++                   tay
+                    pla 
+-                   lsr  a
+                    dey
+                    bne  -
++""")
             }
+            "&" -> asmgen.out(" and  P8ESTACK_LO+1,x")
+            "^" -> asmgen.out(" eor  P8ESTACK_LO+1,x")
+            "|" -> asmgen.out(" ora  P8ESTACK_LO+1,x")
             else -> throw AssemblyError("invalid operator for in-place modification $operator")
         }
+        if(ptrOnZp)
+            asmgen.out("  sta  ($sourceName),y")
+        else
+            asmgen.out("  sta  (P8ZP_SCRATCH_W1),y")
         asmgen.out(" inx")
     }
 
     private fun inplaceModification_byte_variable_to_memory(pointervar: IdentifierReference, operator: String, value: IdentifierReference) {
         val otherName = asmgen.asmVariableName(value)
+        val (ptrOnZp, sourceName) = asmgen.loadByteFromPointerIntoA(pointervar)
+
         when (operator) {
             // note: ** (power) operator requires floats.
-            "+" -> {
-                val (ptrOnZp, sourceName) = asmgen.loadByteFromPointerIntoA(pointervar)
-                asmgen.out(" clc |  adc  $otherName")
-                if(ptrOnZp)
-                    asmgen.out("  sta  ($sourceName),y")
-                else
-                    asmgen.out("  sta  (P8ZP_SCRATCH_W1),y")
+            "+" -> asmgen.out(" clc |  adc  $otherName")
+            "-" -> asmgen.out(" sec |  sbc  $otherName")
+            "*" -> asmgen.out("  ldy  $otherName |  jsr  math.multiply_bytes |  ldy  #0")
+            "/" -> asmgen.out("  ldy  $otherName |  jsr  math.divmod_ub_asm |  tya |  ldy  #0")
+            "%" -> asmgen.out("  ldy  $otherName |  jsr  math.divmod_ub_asm |  ldy  #0")
+            "<<" -> {
+                asmgen.out("""
+                        ldy  $otherName
+                        beq  + 
+-                       asl  a
+                        dey
+                        bne  -
++""")
             }
-            "-" -> {
-                val (ptrOnZp, sourceName) = asmgen.loadByteFromPointerIntoA(pointervar)
-                asmgen.out(" sec |  sbc  $otherName")
-                if(ptrOnZp)
-                    asmgen.out("  sta  ($sourceName),y")
-                else
-                    asmgen.out("  sta  (P8ZP_SCRATCH_W1),y")
-            }
-            "*" -> {
-                TODO("mem mul")// asmgen.out("  jsr  prog8_lib.mul_byte")
-            }
-            "/" -> TODO("mem div")// asmgen.out(if(types==DataType.UBYTE) "  jsr  prog8_lib.idiv_ub" else "  jsr  prog8_lib.idiv_b")
-            "%" -> {
-                TODO("mem byte remainder")
-//                if(types==DataType.BYTE)
-//                    throw AssemblyError("remainder of signed integers is not properly defined/implemented, use unsigned instead")
-//                asmgen.out("  jsr prog8_lib.remainder_ub")
-            }
-            "<<" -> TODO("mem ubyte asl")
-            ">>" -> TODO("mem ubyte lsr")
-            "&" -> {
-                val (ptrOnZp, sourceName) = asmgen.loadByteFromPointerIntoA(pointervar)
-                asmgen.out(" and  $otherName")
-                if(ptrOnZp)
-                    asmgen.out("  sta  ($sourceName),y")
-                else
-                    asmgen.out("  sta  (P8ZP_SCRATCH_W1),y")
-            }
-            "^" -> {
-                val (ptrOnZp, sourceName) = asmgen.loadByteFromPointerIntoA(pointervar)
-                asmgen.out(" eor  $otherName")
-                if(ptrOnZp)
-                    asmgen.out("  sta  ($sourceName),y")
-                else
-                    asmgen.out("  sta  (P8ZP_SCRATCH_W1),y")
-            }
-            "|" -> {
-                val (ptrOnZp, sourceName) = asmgen.loadByteFromPointerIntoA(pointervar)
-                asmgen.out(" ora  $otherName")
-                if(ptrOnZp)
-                    asmgen.out("  sta  ($sourceName),y")
-                else
-                    asmgen.out("  sta  (P8ZP_SCRATCH_W1),y")
+            ">>" -> {
+                asmgen.out("""
+                        ldy  $otherName
+                        beq  + 
+-                       lsr  a
+                        dey
+                        bne  -
++""")
             }
+            "&" -> asmgen.out(" and  $otherName")
+            "^" -> asmgen.out(" eor  $otherName")
+            "|" -> asmgen.out(" ora  $otherName")
             else -> throw AssemblyError("invalid operator for in-place modification $operator")
         }
+        if(ptrOnZp)
+            asmgen.out("  sta  ($sourceName),y")
+        else
+            asmgen.out("  sta  (P8ZP_SCRATCH_W1),y")
     }
 
     private fun inplaceModification_byte_litval_to_memory(pointervar: IdentifierReference, operator: String, value: Int) {
@@ -361,26 +332,35 @@ internal class AugmentableAssignmentAsmGen(private val program: Program,
                     asmgen.out("  sta  (P8ZP_SCRATCH_W1),y")
             }
             "*" -> {
-                if(value in asmgen.optimizedByteMultiplications) {
-                    TODO("optimized mem mul ubyte litval $value")
-                } else {
-                    TODO("mem mul ubyte litval $value")
-                    // asmgen.out("  jsr  prog8_lib.mul_byte")
-                }
+                val (ptrOnZp, sourceName) = asmgen.loadByteFromPointerIntoA(pointervar)
+                if(value in asmgen.optimizedByteMultiplications)
+                    asmgen.out("  jsr  math.mul_byte_${value}")
+                else
+                    asmgen.out("  ldy  #$value |  jsr  math.multiply_bytes |  ldy  #0")
+                if(ptrOnZp)
+                    asmgen.out("  sta  ($sourceName),y")
+                else
+                    asmgen.out("  sta  (P8ZP_SCRATCH_W1),y")
             }
             "/" -> {
+                val (ptrOnZp, sourceName) = asmgen.loadByteFromPointerIntoA(pointervar)
                 if(value==0)
                     throw AssemblyError("division by zero")
-                TODO("mem div byte litval")
-                // asmgen.out(if(types==DataType.UBYTE) "  jsr  prog8_lib.idiv_ub" else "  jsr  prog8_lib.idiv_b")
+                asmgen.out("  ldy  #$value |  jsr  math.divmod_ub_asm |  tya |  ldy  #0")
+                if(ptrOnZp)
+                    asmgen.out("  sta  ($sourceName),y")
+                else
+                    asmgen.out("  sta  (P8ZP_SCRATCH_W1),y")
             }
             "%" -> {
+                val (ptrOnZp, sourceName) = asmgen.loadByteFromPointerIntoA(pointervar)
                 if(value==0)
                     throw AssemblyError("division by zero")
-                TODO("mem byte remainder litval")
-//                if(types==DataType.BYTE)
-//                    throw AssemblyError("remainder of signed integers is not properly defined/implemented, use unsigned instead")
-//                asmgen.out("  jsr prog8_lib.remainder_ub")
+                asmgen.out("  ldy  #$value |  jsr  math.divmod_ub_asm |  ldy  #0")
+                if(ptrOnZp)
+                    asmgen.out("  sta  ($sourceName),y")
+                else
+                    asmgen.out("  sta  (P8ZP_SCRATCH_W1),y")
             }
             "<<" -> {
                 if (value > 0) {
@@ -439,19 +419,17 @@ internal class AugmentableAssignmentAsmGen(private val program: Program,
             // note: ** (power) operator requires floats.
             "+" -> asmgen.out(" lda  $name |  clc |  adc  P8ESTACK_LO+1,x |  sta  $name")
             "-" -> asmgen.out(" lda  $name |  sec |  sbc  P8ESTACK_LO+1,x |  sta  $name")
-            "*" -> {
-                TODO("var mul byte expr")
-                // check optimizedByteMultiplications
-                // asmgen.out("  jsr  prog8_lib.mul_byte")
-            }
+            "*" -> asmgen.out("  lda  P8ESTACK_LO+1,x |  ldy  $name |  jsr  math.multiply_bytes |  sta  $name")
             "/" -> {
-                TODO("var div byte expr")// asmgen.out(if(types==DataType.UBYTE) "  jsr  prog8_lib.idiv_ub" else "  jsr  prog8_lib.idiv_b")
+                if(dt==DataType.UBYTE)
+                    asmgen.out("  lda  P8ESTACK_LO+1,x |  tay |  lda  $name |  jsr  math.divmod_ub_asm |  sty  $name")
+                else
+                    asmgen.out("  lda  P8ESTACK_LO+1,x |  tay |  lda  $name |  jsr  math.divmod_b_asm |  sty  $name")
             }
             "%" -> {
-                TODO("var byte remainder expr")
-//                if(types==DataType.BYTE)
-//                    throw AssemblyError("remainder of signed integers is not properly defined/implemented, use unsigned instead")
-//                asmgen.out("  jsr prog8_lib.remainder_ub")
+                if(dt==DataType.BYTE)
+                    throw AssemblyError("remainder of signed integers is not properly defined/implemented, use unsigned instead")
+                asmgen.out("  lda  P8ESTACK_LO+1,x |  tay |  lda  $name |  jsr  math.divmod_ub_asm |  sta  $name")
             }
             "<<" -> {
                 asmgen.translateExpression(value)
@@ -571,33 +549,16 @@ internal class AugmentableAssignmentAsmGen(private val program: Program,
             "+" -> asmgen.out(" lda  $name |  clc |  adc  #$value |  sta  $name")
             "-" -> asmgen.out(" lda  $name |  sec |  sbc  #$value |  sta  $name")
             "*" -> {
-                if(dt == DataType.UBYTE) {
-                    if(value in asmgen.optimizedByteMultiplications) {
-                        asmgen.out("  lda  $name |  jsr  math.mul_byte_$value |  sta  $name")
-                    } else {
-                        TODO("var mul ubyte litval $value")
-                        // asmgen.out("  jsr  prog8_lib.mul_byte")
-                    }
-                } else {
-                    if(value.absoluteValue in asmgen.optimizedByteMultiplications) {
-                        asmgen.out("  lda  $name |  jsr  math.mul_byte_$value |  sta  $name")
-                    } else {
-                        TODO("var mul sbyte litval $value")
-                        // asmgen.out("  jsr  prog8_lib.mul_byte")
-                    }
-                }
+                if(value in asmgen.optimizedByteMultiplications)
+                    asmgen.out("  lda  $name |  jsr  math.mul_byte_$value |  sta  $name")
+                else
+                    asmgen.out("  lda  $name |  ldy  #$value |  jsr  math.multiply_bytes |  sta  $name")
             }
             "/" -> {
-                if (dt == DataType.UBYTE) {
-                    asmgen.out("""
-                        lda  $name
-                        ldy  #$value
-                        jsr  math.divmod_ub_asm
-                        sty  $name                                              
-                    """)
-                } else {
-                    TODO("var BYTE div  litval")
-                }
+                if (dt == DataType.UBYTE)
+                    asmgen.out("  lda  $name |  ldy  #$value |  jsr  math.divmod_ub_asm |  sty  $name")
+                else
+                    asmgen.out("  lda  $name |  ldy  #$value |  jsr  math.divmod_b_asm |  sty  $name")
             }
             "%" -> {
                 if(dt==DataType.BYTE)
@@ -644,7 +605,7 @@ internal class AugmentableAssignmentAsmGen(private val program: Program,
                     sec
                     sbc  P8ZP_SCRATCH_B1
                     sta  $name""")
-                // TODO: more operators
+                // TODO: tuned code for more operators
             }
             else -> {
                 inplaceModification_byte_value_to_variable(name, dt, operator, memread);
@@ -675,7 +636,7 @@ internal class AugmentableAssignmentAsmGen(private val program: Program,
                     bcc  +
                     dec  $name+1
 +""")
-                // TODO: more operators
+                // TODO: tuned code for more operators
             }
             else -> {
                 inplaceModification_word_value_to_variable(name, dt, operator, memread);
@@ -1072,6 +1033,68 @@ internal class AugmentableAssignmentAsmGen(private val program: Program,
         asmgen.translateExpression(value)
         val valueDt = value.inferType(program).typeOrElse(DataType.STRUCT)
 
+        fun multiplyWord() {
+            asmgen.out("""
+                lda  P8ESTACK_LO+1,x
+                ldy  P8ESTACK_HI+1,x
+                sta  P8ZP_SCRATCH_W1
+                sty  P8ZP_SCRATCH_W1+1
+                lda  $name
+                ldy  $name+1
+                jsr  math.multiply_words
+                lda  math.multiply_words.result
+                sta  $name
+                lda  math.multiply_words.result+1
+                sta  $name+1
+            """)
+        }
+
+        fun divideWord() {
+            if (dt == DataType.WORD) {
+                asmgen.out("""
+                    lda  $name
+                    ldy  $name+1
+                    sta  P8ZP_SCRATCH_W1
+                    sty  P8ZP_SCRATCH_W1+1
+                    lda  P8ESTACK_LO+1,x
+                    ldy  P8ESTACK_HI+1,x
+                    jsr  math.divmod_w_asm
+                    sta  $name
+                    sty  $name+1
+                """)
+            } else {
+                asmgen.out("""
+                    lda  $name
+                    ldy  $name+1
+                    sta  P8ZP_SCRATCH_W1
+                    sty  P8ZP_SCRATCH_W1+1
+                    lda  P8ESTACK_LO+1,x
+                    ldy  P8ESTACK_HI+1,x
+                    jsr  math.divmod_uw_asm
+                    sta  $name
+                    sty  $name+1
+                """)
+            }
+        }
+
+        fun remainderWord() {
+            if(dt==DataType.WORD)
+                throw AssemblyError("remainder of signed integers is not properly defined/implemented, use unsigned instead")
+            asmgen.out("""
+                lda  $name
+                ldy  $name+1
+                sta  P8ZP_SCRATCH_W1
+                sty  P8ZP_SCRATCH_W1+1
+                lda  P8ESTACK_LO+1,x
+                ldy  P8ESTACK_HI+1,x
+                jsr  math.divmod_uw_asm
+                lda  P8ZP_SCRATCH_W2
+                sta  $name
+                lda  P8ZP_SCRATCH_W2+1
+                sta  $name+1
+            """)
+        }
+
         when(valueDt) {
             in ByteDatatypes -> {
                 // the other variable is a BYTE type so optimize for that
@@ -1125,9 +1148,21 @@ internal class AugmentableAssignmentAsmGen(private val program: Program,
                                 sbc  P8ZP_SCRATCH_B1
                                 sta  $name+1""")
                     }
-                    "*" -> TODO("mul (u)word (u)byte")
-                    "/" -> TODO("div (u)word (u)byte")
-                    "%" -> TODO("(u)word remainder (u)byte")
+                    "*" -> {
+                        // stack contains (u) byte value, sign extend that and proceed with regular 16 bit operation
+                        asmgen.signExtendStackLsb(valueDt)
+                        multiplyWord()
+                    }
+                    "/" -> {
+                        // stack contains (u) byte value, sign extend that and proceed with regular 16 bit operation
+                        asmgen.signExtendStackLsb(valueDt)
+                        divideWord()
+                    }
+                    "%" -> {
+                        // stack contains (u) byte value, sign extend that and proceed with regular 16 bit operation
+                        asmgen.signExtendStackLsb(valueDt)
+                        remainderWord()
+                    }
                     "<<" -> {
                         asmgen.translateExpression(value)
                         asmgen.out("""
@@ -1166,9 +1201,9 @@ internal class AugmentableAssignmentAsmGen(private val program: Program,
 +""")
                         }
                     }
-                    "&" -> TODO("bitand (u)word (u)byte")
-                    "^" -> TODO("bitxor (u)word (u)byte")
-                    "|" -> TODO("bitor (u)word (u)byte")
+                    "&" -> TODO("bitand (u)word (u)byte on stack")
+                    "^" -> TODO("bitxor (u)word (u)byte on stack")
+                    "|" -> TODO("bitor (u)word (u)byte on stack")
                     else -> throw AssemblyError("invalid operator for in-place modification $operator")
                 }
             }
@@ -1178,65 +1213,9 @@ internal class AugmentableAssignmentAsmGen(private val program: Program,
                     // note: ** (power) operator requires floats.
                     "+" -> asmgen.out(" lda  $name |  clc |  adc  P8ESTACK_LO+1,x |  sta  $name |  lda  $name+1 |  adc  P8ESTACK_HI+1,x |  sta  $name+1")
                     "-" -> asmgen.out(" lda  $name |  sec |  sbc  P8ESTACK_LO+1,x |  sta  $name |  lda  $name+1 |  sbc  P8ESTACK_HI+1,x |  sta  $name+1")
-                    "*" -> {
-                        asmgen.out("""
-                            lda  P8ESTACK_LO+1,x
-                            ldy  P8ESTACK_HI+1,x
-                            sta  P8ZP_SCRATCH_W1
-                            sty  P8ZP_SCRATCH_W1+1
-                            lda  $name
-                            ldy  $name+1
-                            jsr  math.multiply_words
-                            lda  math.multiply_words.result
-                            sta  $name
-                            lda  math.multiply_words.result+1
-                            sta  $name+1
-                        """)
-                    }
-                    "/" -> {
-                        if (dt == DataType.WORD) {
-                            asmgen.out("""
-                                lda  $name
-                                ldy  $name+1
-                                sta  P8ZP_SCRATCH_W1
-                                sty  P8ZP_SCRATCH_W1+1
-                                lda  P8ESTACK_LO+1,x
-                                ldy  P8ESTACK_HI+1,x
-                                jsr  math.divmod_w_asm
-                                sta  $name
-                                sty  $name+1
-                            """)
-                        } else {
-                            asmgen.out("""
-                                lda  $name
-                                ldy  $name+1
-                                sta  P8ZP_SCRATCH_W1
-                                sty  P8ZP_SCRATCH_W1+1
-                                lda  P8ESTACK_LO+1,x
-                                ldy  P8ESTACK_HI+1,x
-                                jsr  math.divmod_uw_asm
-                                sta  $name
-                                sty  $name+1
-                            """)
-                        }
-                    }
-                    "%" -> {
-                        if(dt==DataType.WORD)
-                            throw AssemblyError("remainder of signed integers is not properly defined/implemented, use unsigned instead")
-                        asmgen.out("""
-                            lda  $name
-                            ldy  $name+1
-                            sta  P8ZP_SCRATCH_W1
-                            sty  P8ZP_SCRATCH_W1+1
-                            lda  P8ESTACK_LO+1,x
-                            ldy  P8ESTACK_HI+1,x
-                            jsr  math.divmod_uw_asm
-                            lda  P8ZP_SCRATCH_W2
-                            sta  $name
-                            lda  P8ZP_SCRATCH_W2+1
-                            sta  $name+1
-                        """)
-                    }
+                    "*" -> multiplyWord()
+                    "/" -> divideWord()
+                    "%" -> remainderWord()
                     "<<", ">>" -> throw AssemblyError("shift by a word value not supported, max is a byte")
                     "&" -> asmgen.out(" lda  $name |  and  P8ESTACK_LO+1,x |  sta  $name | lda  $name+1 |  and  P8ESTACK_HI+1,x  |  sta  $name+1")
                     "^" -> asmgen.out(" lda  $name |  eor  P8ESTACK_LO+1,x |  sta  $name | lda  $name+1 |  eor  P8ESTACK_HI+1,x  |  sta  $name+1")
@@ -1252,13 +1231,13 @@ internal class AugmentableAssignmentAsmGen(private val program: Program,
         asmgen.out(" inx")
     }
 
-    private fun inplaceModification_float_value_to_variable(name: String, operator: String, value: Expression) {
+    private fun inplaceModification_float_value_to_variable(name: String, operator: String, value: Expression, scope: Subroutine?) {
         // this should be the last resort for code generation for this,
         // because the value is evaluated onto the eval stack (=slow).
         println("warning: slow stack evaluation used (2):  $name $operator= ${value::class.simpleName} at ${value.position}") // TODO
         asmgen.translateExpression(value)
         asmgen.out("  jsr  floats.pop_float_fac1")
-        asmgen.saveRegister(CpuRegister.X)
+        asmgen.saveRegister(CpuRegister.X, false, scope)
         when (operator) {
             "**" -> {
                 asmgen.out("""
@@ -1303,16 +1282,16 @@ internal class AugmentableAssignmentAsmGen(private val program: Program,
             ldy  #>$name
             jsr  floats.MOVMF
         """)
-        asmgen.restoreRegister(CpuRegister.X)
+        asmgen.restoreRegister(CpuRegister.X, false)
     }
 
-    private fun inplaceModification_float_variable_to_variable(name: String, operator: String, ident: IdentifierReference) {
+    private fun inplaceModification_float_variable_to_variable(name: String, operator: String, ident: IdentifierReference, scope: Subroutine?) {
         val valueDt = ident.targetVarDecl(program.namespace)!!.datatype
         if(valueDt != DataType.FLOAT)
             throw AssemblyError("float variable expected")
 
         val otherName = asmgen.asmVariableName(ident)
-        asmgen.saveRegister(CpuRegister.X)
+        asmgen.saveRegister(CpuRegister.X, false, scope)
         when (operator) {
             "**" -> {
                 asmgen.out("""
@@ -1372,12 +1351,12 @@ internal class AugmentableAssignmentAsmGen(private val program: Program,
             ldy  #>$name
             jsr  floats.MOVMF
         """)
-        asmgen.restoreRegister(CpuRegister.X)
+        asmgen.restoreRegister(CpuRegister.X, false)
     }
 
-    private fun inplaceModification_float_litval_to_variable(name: String, operator: String, value: Double) {
+    private fun inplaceModification_float_litval_to_variable(name: String, operator: String, value: Double, scope: Subroutine?) {
         val constValueName = asmgen.getFloatAsmConst(value)
-        asmgen.saveRegister(CpuRegister.X)
+        asmgen.saveRegister(CpuRegister.X, false, scope)
         when (operator) {
             "**" -> {
                 asmgen.out("""
@@ -1444,7 +1423,7 @@ internal class AugmentableAssignmentAsmGen(private val program: Program,
             ldy  #>$name
             jsr  floats.MOVMF
         """)
-        asmgen.restoreRegister(CpuRegister.X)
+        asmgen.restoreRegister(CpuRegister.X, false)
     }
 
     private fun inplaceCast(target: AsmAssignTarget, cast: TypecastExpression, position: Position) {

compiler/src/prog8/functions/BuiltinFunctions.kt

@@ -285,9 +285,9 @@ private fun builtinStrlen(args: List<Expression>, position: Position, program: P
         return NumericLiteralValue.optimalInteger(argument.value.length, argument.position)
     val vardecl = (argument as IdentifierReference).targetVarDecl(program.namespace)
     if(vardecl!=null) {
-        if(vardecl.datatype!=DataType.STR)
+        if(vardecl.datatype!=DataType.STR && vardecl.datatype!=DataType.UWORD)
             throw SyntaxError("strlen must have string argument", position)
-        if(vardecl.autogeneratedDontRemove) {
+        if(vardecl.autogeneratedDontRemove && vardecl.value!=null) {
             return NumericLiteralValue.optimalInteger((vardecl.value as StringLiteralValue).value.length, argument.position)
         }
     }

compiler/src/prog8/optimizer/BinExprSplitter.kt

@@ -0,0 +1,89 @@
+package prog8.optimizer
+
+import prog8.ast.INameScope
+import prog8.ast.Node
+import prog8.ast.Program
+import prog8.ast.expressions.*
+import prog8.ast.processing.AstWalker
+import prog8.ast.processing.IAstModification
+import prog8.ast.statements.AssignTarget
+import prog8.ast.statements.Assignment
+
+
+internal class BinExprSplitter(private val program: Program) : AstWalker() {
+    private val noModifications = emptyList<IAstModification>()
+
+//    override fun after(decl: VarDecl, parent: Node): Iterable<IAstModification> {
+// TODO somehow if we do this, the resulting code for some programs (cube3d.p8) gets hundreds of bytes larger...:
+//        if(decl.type==VarDeclType.VAR ) {
+//            val binExpr = decl.value as? BinaryExpression
+//            if (binExpr != null && binExpr.operator in augmentAssignmentOperators) {
+//                // split into a vardecl with just the left expression, and an aug. assignment with the right expression.
+//                val augExpr = BinaryExpression(IdentifierReference(listOf(decl.name), decl.position), binExpr.operator, binExpr.right, binExpr.position)
+//                val target = AssignTarget(IdentifierReference(listOf(decl.name), decl.position), null, null, decl.position)
+//                val assign = Assignment(target, augExpr, binExpr.position)
+//                println("SPLIT VARDECL $decl")
+//                return listOf(
+//                        IAstModification.SetExpression({ decl.value = it }, binExpr.left, decl),
+//                        IAstModification.InsertAfter(decl, assign, parent)
+//                )
+//            }
+//        }
+//        return noModifications
+//    }
+
+    override fun after(assignment: Assignment, parent: Node): Iterable<IAstModification> {
+
+        val binExpr = assignment.value as? BinaryExpression
+        if (binExpr != null) {
+/*
+
+reduce the complexity of a (binary) expression that has to be evaluated on the eval stack,
+by attempting to splitting it up into individual simple steps:
+
+
+X =      BinExpr                                   X   =   LeftExpr
+        <operator>                                   followed by
+          /   \              IF 'X' not used       X   =   BinExpr
+         /     \               IN LEFTEXPR ==>             <operator>
+        /       \                                           /   \
+    LeftExpr.  RightExpr.                                  /     \
+      /  \       /  \                                     X     RightExpr.
+    ..  ..      ..  ..
+
+ */
+            if(binExpr.operator in augmentAssignmentOperators && isSimpleTarget(assignment.target, program.namespace)) {
+                if (!assignment.isAugmentable) {
+                    val firstAssign = Assignment(assignment.target, binExpr.left, binExpr.left.position)
+                    val targetExpr = assignment.target.toExpression()
+                    val augExpr = BinaryExpression(targetExpr, binExpr.operator, binExpr.right, binExpr.right.position)
+                    return listOf(
+                            IAstModification.InsertBefore(assignment, firstAssign, parent),
+                            IAstModification.ReplaceNode(assignment.value, augExpr, assignment))
+                }
+            }
+
+            // TODO further unraveling of binary expression trees into flat statements.
+            // however this should probably be done in a more generic way to also service
+            // the expressiontrees that are not used in an assignment statement...
+        }
+
+        return noModifications
+    }
+
+    private fun isSimpleTarget(target: AssignTarget, namespace: INameScope): Boolean {
+        return when {
+            target.identifier!=null -> target.isInRegularRAM(namespace)
+            target.memoryAddress!=null -> target.isInRegularRAM(namespace)
+            target.arrayindexed!=null -> {
+                val index = target.arrayindexed!!.arrayspec.index
+                if(index is NumericLiteralValue)
+                    target.isInRegularRAM(namespace)
+                else
+                    false
+            }
+            else -> false
+        }
+    }
+
+}

compiler/src/prog8/optimizer/ExpressionSimplifier.kt

@@ -1,15 +1,11 @@
 package prog8.optimizer
 
-import prog8.ast.INameScope
 import prog8.ast.Node
 import prog8.ast.Program
 import prog8.ast.base.*
 import prog8.ast.expressions.*
 import prog8.ast.processing.AstWalker
 import prog8.ast.processing.IAstModification
-import prog8.ast.statements.AssignTarget
-import prog8.ast.statements.Assignment
-import prog8.ast.statements.VarDecl
 import kotlin.math.abs
 import kotlin.math.log2
 import kotlin.math.pow
@@ -279,80 +275,6 @@ internal class ExpressionSimplifier(private val program: Program) : AstWalker()
         return noModifications
     }
 
-
-//    override fun after(decl: VarDecl, parent: Node): Iterable<IAstModification> {
-// TODO somehow if we do this, the resulting code for some programs (cube3d.p8) gets hundreds of bytes larger...:
-//        if(decl.type==VarDeclType.VAR ) {
-//            val binExpr = decl.value as? BinaryExpression
-//            if (binExpr != null && binExpr.operator in augmentAssignmentOperators) {
-//                // split into a vardecl with just the left expression, and an aug. assignment with the right expression.
-//                val augExpr = BinaryExpression(IdentifierReference(listOf(decl.name), decl.position), binExpr.operator, binExpr.right, binExpr.position)
-//                val target = AssignTarget(IdentifierReference(listOf(decl.name), decl.position), null, null, decl.position)
-//                val assign = Assignment(target, augExpr, binExpr.position)
-//                println("SPLIT VARDECL $decl")
-//                return listOf(
-//                        IAstModification.SetExpression({ decl.value = it }, binExpr.left, decl),
-//                        IAstModification.InsertAfter(decl, assign, parent)
-//                )
-//            }
-//        }
-//        return noModifications
-//    }
-
-    override fun after(assignment: Assignment, parent: Node): Iterable<IAstModification> {
-
-        val binExpr = assignment.value as? BinaryExpression
-        if (binExpr != null) {
-/*
-
-reduce the complexity of a (binary) expression that has to be evaluated on the eval stack,
-by attempting to splitting it up into individual simple steps:
-
-
-X =      BinExpr                                   X   =   LeftExpr
-        <operator>                                   followed by
-          /   \              IF 'X' not used       X   =   BinExpr
-         /     \               IN LEFTEXPR ==>             <operator>
-        /       \                                           /   \
-    LeftExpr.  RightExpr.                                  /     \
-      /  \       /  \                                     X     RightExpr.
-    ..  ..      ..  ..
-
- */
-            if(binExpr.operator in augmentAssignmentOperators && isSimpleTarget(assignment.target, program.namespace)) {
-                if (!assignment.isAugmentable) {
-                    val firstAssign = Assignment(assignment.target, binExpr.left, binExpr.left.position)
-                    val targetExpr = assignment.target.toExpression()
-                    val augExpr = BinaryExpression(targetExpr, binExpr.operator, binExpr.right, binExpr.right.position)
-                    return listOf(
-                            IAstModification.InsertBefore(assignment, firstAssign, parent),
-                            IAstModification.ReplaceNode(assignment.value, augExpr, assignment))
-                }
-            }
-
-            // TODO further unraveling of binary expression trees into flat statements.
-            // however this should probably be done in a more generic way to also service
-            // the expressiontrees that are not used in an assignment statement...
-        }
-
-        return noModifications
-    }
-
-    private fun isSimpleTarget(target: AssignTarget, namespace: INameScope): Boolean {
-        return when {
-            target.identifier!=null -> target.isInRegularRAM(namespace)
-            target.memoryAddress!=null -> target.isInRegularRAM(namespace)
-            target.arrayindexed!=null -> {
-                val index = target.arrayindexed!!.arrayspec.index
-                if(index is NumericLiteralValue)
-                    target.isInRegularRAM(namespace)
-                else
-                    false
-            }
-            else -> false
-        }
-    }
-
     override fun after(functionCall: FunctionCall, parent: Node): Iterable<IAstModification> {
         if(functionCall.target.nameInSource == listOf("lsb")) {
             val arg = functionCall.args[0]

compiler/src/prog8/optimizer/Extensions.kt

@@ -53,3 +53,9 @@ internal fun Program.simplifyExpressions() : Int {
     opti.visit(this)
     return opti.applyModifications()
 }
+
+internal fun Program.splitBinaryExpressions() : Int {
+    val opti = BinExprSplitter(this)
+    opti.visit(this)
+    return opti.applyModifications()
+}

docs/source/index.rst

@@ -96,6 +96,12 @@ when compiled an ran on a C-64 you get this:
     :align: center
     :alt: result when run on C-64
 
+when the exact same program is compiled for the Commander X16 target, and run on the emulator, you get this:
+
+.. image:: _static/primes_cx16.png
+    :align: center
+    :alt: result when run on CX16 emulator
+
 
 
 Design principles and features

docs/source/programming.rst

@@ -260,6 +260,11 @@ 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.
 
+It's possible to assign a new array to another array, this will overwrite all elements in the original
+array with those in the value array. The number and types of elements have to match.
+For large arrays this is a slow operation because every element is copied over. It should probably be avoided.
+
+
 **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::
@@ -287,7 +292,7 @@ This @-prefix can also be used for character byte values.
 You can concatenate two string literals using '+' (not very useful though) or repeat
 a string literal a given number of times using '*'. You can also assign a new string
 value to another string. No bounds check is done so be sure the destination string is
-large enough to contain the new value::
+large enough to contain the new value (it is overwritten in memory)::
 
     str string1 = "first part" + "second part"
     str string2 = "hello!" * 10
@@ -296,7 +301,13 @@ large enough to contain the new value::
     string1 = "new value"
 
 
-.. info::
+There are several 'escape sequences' to help you put special characters into strings, such
+as newlines, quote characters themselves, and so on. The ones used most often are
+``\\``, ``\"``, ``\n``, ``\r``.  For a detailed description of all of them and what they mean,
+read the syntax reference on strings.
+
+
+.. note::
     Strings and uwords (=memory address) can often be interchanged.
     An array of strings is actually an array of uwords where every element is the memory
     address of the string. You can pass a memory address to assembly functions

docs/source/syntaxreference.rst

@@ -78,7 +78,7 @@ Directives
     - style ``full`` -- claim the whole ZP for variables for the program, overwriting everything,
       except the few addresses mentioned above that are used by the system's IRQ routine.
       Even though the default IRQ routine is still active, it is impossible to use most BASIC and KERNAL ROM routines.
-      This includes many floating point operations and several utility routines that do I/O, such as ``print_string``.
+      This includes many floating point operations and several utility routines that do I/O, such as ``print``.
       This option makes programs smaller and faster because even more variables can
       be stored in the ZP (which allows for more efficient assembly code).
       It's not possible to return cleanly to BASIC when the program exits. The only choice is
@@ -402,6 +402,24 @@ Struct variables can be assigned a struct literal value (also in their declarati
     Color rgb = [255, 100, 0]          ; note that the value is an array
 
 
+String
+^^^^^^
+
+``"hello"``   is a string translated into the default character encoding (PETSCII)
+
+``@"hello"``  is a string translated into the alternate character encoding (Screencodes/pokes)
+
+There are several escape sequences available to put special characters into your string value:
+
+- ``\\`` - the backslash itself, has to be escaped because it is the escape symbol by itself
+- ``\n`` - newline character (move cursor down and to beginning of next line)
+- ``\r`` - carriage return character (more or less the same as newline if printing to the screen)
+- ``\"`` - quote character (otherwise it would terminate the string)
+- ``\'`` - apostrophe character (has to be escaped in character literals, is okay inside a string)
+- ``\uHHHH`` - a unicode codepoint \u0000 - \uffff (16-bit hexadecimal)
+- ``\xHH`` - 8-bit hex value that will be copied verbatim *without encoding*
+
+
 Operators
 ---------
 
@@ -486,6 +504,8 @@ takes no parameters.  If the subroutine returns a value, usually you assign it t
 If you're not interested in the return value, prefix the function call with the ``void`` keyword.
 Otherwise the compiler will warn you about discarding the result of the call.
 
+Multiple return values
+^^^^^^^^^^^^^^^^^^^^^^
 Normal subroutines can only return zero or one return values.
 However, the special ``asmsub`` routines (implemented in assembly code) or ``romsub`` routines
 (referencing a routine in kernel ROM) can return more than one return value.
@@ -493,9 +513,16 @@ For example a status in the carry bit and a number in A, or a 16-bit value in A/
 It is not possible to process the results of a call to these kind of routines
 directly from the language, because only single value assignments are possible.
 You can still call the subroutine and not store the results.
-But if you want to do something with the values it returns, you'll have to write
-a small block of custom inline assembly that does the call and stores the values
-appropriately. Don't forget to save/restore the registers if required.
+
+**There is an exception:** if there's just one return value in a register, and one or more others that are returned
+as bits in the status register (such as the Carry bit), the compiler allows you to call the subroutine.
+It will then store the result value in a variable if required, and *keep the status register untouched
+after the call* so you can use a conditional branch statement for that.
+Note that this makes no sense inside an expression, so the compiler will still give an error for that.
+
+If there really are multiple return values (other than a combined 16 bit return value in 2 registers),
+you'll have to write a small block of custom inline assembly that does the call and stores the values
+appropriately. Don't forget to save/restore any registers that are modified.
 
 
 Subroutine definitions

docs/source/todo.rst

@@ -3,7 +3,6 @@ TODO
 ====
 
 - get rid of all other TODO's in the code ;-)
-- make it possible for array literals to not only contain compile time constants?
 - implement @stack for asmsub parameters
 - make it possible to use cpu opcodes such as 'nop' as variable names by prefixing all asm vars with something such as '_'
 - option to load the built-in library files from a directory instead of the embedded ones (for easier library development/debugging)
@@ -19,7 +18,7 @@ Add more compiler optimizations to the existing ones.
 
 - further optimize assignment codegeneration, such as the following:
 - binexpr splitting (beware self-referencing expressions and asm code ballooning though)
-- subroutine calling convention? like: 1 byte arg -> pass in A, 2 bytes -> pass in A+Y, return value likewise.
+- subroutine calling convention? like: 1 byte arg -> pass in A, 2 bytes -> pass in A+Y, return value likewise.  Especially for built-in functions!
 - can such parameter passing to subroutines be optimized to avoid copying?
 - more optimizations on the language AST level
 - more optimizations on the final assembly source level

examples/cx16/simplegraphics.p8

@@ -3,12 +3,14 @@
 %target cx16
 %zeropage basicsafe
 
+
 main {
 
     sub start() {
 
         void cx16.screen_set_mode($80)
         cx16.r0=0
+        void cx16.screen_set_mode(0)
 
         cx16.FB_init()
         cx16.GRAPH_init()

examples/diskdir-sys50000.p8

@@ -10,38 +10,6 @@
 ; You load it with  LOAD "diskdir-sys50000",8,1
 ; and then call it with SYS 50000.
 
-main {
-    sub start() {
-        txt.print("directory of disk drive #8:\n\n")
-        diskdir(8)
-    }
+; The only difference with diskdir.p8 is the directives that make this load at 50000.
 
-    sub diskdir(ubyte drivenumber) {
-        c64.SETNAM(1, "$")
-        c64.SETLFS(1, drivenumber, 0)
-        c64.OPEN()          ; open 1,8,0,"$"
-        c64.CHKIN(1)        ; use #1 as input channel
-
-        repeat 4 {
-            void c64.CHRIN()     ; skip the 4 prologue bytes
-        }
-
-        ; while not key pressed / EOF encountered, read data.
-        while not (@($c6) | c64.STATUS) {
-            txt.print_uw(mkword(c64.CHRIN(), c64.CHRIN()))
-            txt.chrout(' ')
-            ubyte @zp char
-            do {
-                char = c64.CHRIN()
-                txt.chrout(char)
-            } until char==0
-            txt.chrout('\n')
-            repeat 2 {
-                void c64.CHRIN()     ; skip 2 bytes
-            }
-        }
-
-        c64.CLOSE(1)
-        c64.CLRCHN()        ; restore default i/o devices
-    }
-}
+%import diskdir

examples/diskdir.p8

@@ -1,10 +1,10 @@
-%target c64
 %import textio
 %import syslib
 %option no_sysinit
 %zeropage basicsafe
 
 ; This example shows the directory contents of disk drive 8.
+; Note: this program is compatible with C64 and CX16.
 
 main {
     sub start() {
@@ -15,15 +15,20 @@ main {
     sub diskdir(ubyte drivenumber) {
         c64.SETNAM(1, "$")
         c64.SETLFS(1, drivenumber, 0)
-        c64.OPEN()          ; open 1,8,0,"$"
-        c64.CHKIN(1)        ; use #1 as input channel
+        void c64.OPEN()          ; open 1,8,0,"$"
+        if_cs
+            goto io_error
+        void c64.CHKIN(1)        ; use #1 as input channel
+        if_cs
+            goto io_error
 
         repeat 4 {
             void c64.CHRIN()     ; skip the 4 prologue bytes
         }
 
         ; while not key pressed / EOF encountered, read data.
-        while not (@($c6) | c64.STATUS) {
+        ubyte status = c64.READST()
+        while not status {
             txt.print_uw(mkword(c64.CHRIN(), c64.CHRIN()))
             txt.chrout(' ')
             ubyte @zp char
@@ -32,12 +37,23 @@ main {
                 txt.chrout(char)
             } until char==0
             txt.chrout('\n')
-            repeat 2 {
-                void c64.CHRIN()     ; skip 2 bytes
-            }
+            void c64.CHRIN()     ; skip 2 bytes
+            void c64.CHRIN()
+            status = c64.READST()
+            void c64.STOP()
+            if_nz
+                break
         }
 
-        c64.CLOSE(1)
+io_error:
+        status = c64.READST()
         c64.CLRCHN()        ; restore default i/o devices
+        c64.CLOSE(1)
+
+        if status and status != 64 {            ; 64=end of file
+            txt.print("\ni/o error, status: ")
+            txt.print_ub(status)
+            txt.chrout('\n')
+        }
     }
 }

examples/mandelbrot-gfx.p8

@@ -9,14 +9,14 @@
 ; Note: this program is compatible with C64 and CX16.
 
 main {
-    const ubyte width = 255
+    const uword width = 320
     const ubyte height = 200
     const ubyte max_iter = 16
 
     sub start()  {
         graphics.enable_bitmap_mode()
 
-        ubyte pixelx
+        uword pixelx
         ubyte pixely
 
         for pixely in 0 to height-1 {

examples/numbergame.p8

@@ -30,7 +30,7 @@ main {
                 txt.print("es")
             txt.print(" left.\nWhat is your next guess? ")
             void txt.input_chars(input)
-            ubyte guess = lsb(conv.str2uword(input))
+            ubyte guess = conv.str2ubyte(input)
 
             if guess==secretnumber {
                 ending(true)

examples/tehtriz.p8

@@ -249,8 +249,10 @@ waitkey:
         txt.print("────────────────────────")
         c64.CHROUT('K')
 
-        while c64.GETIN()!=133 {
+        ubyte key = 0
+        while key!=133 {
             ; endless loop until user presses F1 to restart the game
+            key = c64.GETIN()
         }
     }
 

examples/test.p8

@@ -6,37 +6,8 @@
 
 main {
 
-    struct Color {
-        ubyte red
-        ubyte green
-        ubyte blue
-    }
-
-    Color c1 = [11,22,33]
-    Color c2 = [11,22,33]
-    Color c3 = [11,22,33]
-    uword[] colors = [ c1, c2, c3]
-
-
     sub start() {
 
-        txt.print_ub(c1.red)
-        txt.chrout('\n')
-        txt.print_ub(c1.green)
-        txt.chrout('\n')
-        txt.print_ub(c1.blue)
-        txt.chrout('\n')
-        txt.chrout('\n')
-
-        c1 = [99,88,77]
-
-        txt.print_ub(c1.red)
-        txt.chrout('\n')
-        txt.print_ub(c1.green)
-        txt.chrout('\n')
-        txt.print_ub(c1.blue)
-        txt.chrout('\n')
-        testX()
     }
 
     asmsub testX() {
@@ -53,5 +24,7 @@ main {
 _saveX   .byte 0
         }}
     }
-
 }
+
+
+

examples/testarrays.p8

@@ -18,7 +18,6 @@ main {
 
         &str  ms1 = $c000
 
-
         byte[4] barray
         ubyte[4] ubarray
         word[4] warray

examples/textelite.p8

@@ -0,0 +1,941 @@
+%import textio
+%import conv
+%option no_sysinit
+%zeropage basicsafe
+
+; Prog8 adaptation of the Text-Elite galaxy system trading simulation engine.
+; Original C-version obtained from: http://www.elitehomepage.org/text/index.htm
+
+; Note: this program is compatible with C64 and CX16.
+
+
+; TODO save/load game function
+
+main {
+
+    const ubyte numforLave = 7      ;  Lave is 7th generated planet in galaxy one
+    const ubyte numforZaonce = 129
+    const ubyte numforDiso = 147
+    const ubyte numforRiedquat = 46
+
+    sub start() {
+        txt.lowercase()
+        txt.print("\u000c\n --- TextElite v1.0 ---\n")
+
+        galaxy.init(1)
+        galaxy.travel_to(numforLave)
+        market.init(0)  ;  Lave's market is seeded with 0
+        ship.init()
+        planet.display(false)
+
+        repeat {
+            str input = "????????"
+            txt.print("\nCash: ")
+            util.print_10s(ship.cash)
+            txt.print("\nCommand (?=help): ")
+            ubyte num_chars = txt.input_chars(input)
+            txt.chrout('\n')
+            if num_chars {
+                when input[0] {
+                    '?' -> {
+                        txt.print("\nCommands are:\n"+
+                            "buy   jump      info    cash   >=save\n"+
+                            "sell  teleport  market  hold   <=load\n"+
+                            "fuel  galhyp    local          quit\n")
+                    }
+                    'q' -> break
+                    'b' -> trader.do_buy()
+                    's' -> trader.do_sell()
+                    'f' -> trader.do_fuel()
+                    'j' -> trader.do_jump()
+                    't' -> trader.do_teleport()
+                    'g' -> trader.do_next_galaxy()
+                    'i' -> trader.do_info()
+                    'm' -> trader.do_show_market()
+                    'l' -> trader.do_local()
+                    'c' -> trader.do_cash()
+                    'h' -> trader.do_hold()
+                    '<' -> trader.do_load()
+                    '>' -> trader.do_save()
+                }
+            }
+        }
+    }
+}
+
+trader {
+    str input = "??????????"
+    ubyte num_chars
+
+    sub do_load() {
+        txt.print("\nTODO LOAD\n")
+    }
+
+    sub do_save() {
+        txt.print("\nTODO SAVE\n")
+    }
+
+    sub do_jump() {
+        txt.print("\nJump to what system? ")
+        jump_to_system()
+    }
+
+    sub do_teleport() {
+        txt.print("\nCheat! Teleport to what system? ")
+        ubyte fuel = ship.fuel
+        ship.fuel = 255
+        jump_to_system()
+        ship.fuel = fuel
+    }
+
+    sub jump_to_system() {
+        void txt.input_chars(input)
+        ubyte current_planet = planet.number
+        ubyte x = planet.x
+        ubyte y = planet.y
+        if galaxy.search_closest_planet(input) {
+            ubyte distance = planet.distance(x, y)
+            if distance <= ship.fuel {
+                galaxy.init_market_for_planet()
+                ship.fuel -= distance
+                txt.print("\n\nHyperspace jump! Arrived at:\n")
+                planet.display(true)
+                return
+            }
+            txt.print("Insufficient fuel\n")
+        } else {
+            txt.print(" Not found!\n")
+        }
+        galaxy.travel_to(current_planet)
+    }
+
+    sub do_buy() {
+        txt.print("\nBuy what commodity? ")
+        str commodity = "???????????????"
+        void txt.input_chars(commodity)
+        ubyte ci = market.match(commodity)
+        if ci & 128 {
+            txt.print("Unknown\n")
+        } else {
+            txt.print("\nHow much? ")
+            void txt.input_chars(input)
+            ubyte amount = conv.str2ubyte(input)
+            if market.current_quantity[ci] < amount {
+                txt.print(" Insufficient supply!\n")
+            } else {
+                uword price = market.current_price[ci] * amount
+                txt.print(" Total price: ")
+                util.print_10s(price)
+                if price > ship.cash {
+                    txt.print(" Not enough cash!\n")
+                } else {
+                    ship.cash -= price
+                    ship.cargohold[ci] += amount
+                    market.current_quantity[ci] -= amount
+                }
+            }
+        }
+    }
+
+    sub do_sell() {
+        txt.print("\nSell what commodity? ")
+        str commodity = "???????????????"
+        void txt.input_chars(commodity)
+        ubyte ci = market.match(commodity)
+        if ci & 128 {
+            txt.print("Unknown\n")
+        } else {
+            txt.print("\nHow much? ")
+            void txt.input_chars(input)
+            ubyte amount = conv.str2ubyte(input)
+            if ship.cargohold[ci] < amount {
+                txt.print(" Insufficient supply!\n")
+            } else {
+                uword price = market.current_price[ci] * amount
+                txt.print(" Total price: ")
+                util.print_10s(price)
+                ship.cash += price
+                ship.cargohold[ci] -= amount
+                market.current_quantity[ci] += amount
+            }
+        }
+    }
+
+    sub do_fuel() {
+        txt.print("\nBuy fuel. Amount? ")
+        void txt.input_chars(input)
+        ubyte buy_fuel = 10*conv.str2ubyte(input)
+        ubyte max_fuel = ship.Max_fuel - ship.fuel
+        if buy_fuel > max_fuel
+            buy_fuel = max_fuel
+        uword price = buy_fuel as uword * ship.Fuel_cost
+        if price > ship.cash {
+            txt.print("Not enough cash!\n")
+        } else {
+            ship.cash -= price
+            ship.fuel += buy_fuel
+        }
+    }
+
+    sub do_cash() {
+        txt.print("\nCheat! Set cash amount: ")
+        void txt.input_chars(input)
+        ship.cash = conv.str2uword(input)
+    }
+
+    sub do_hold() {
+        txt.print("\nCheat! Set cargohold size: ")
+        void txt.input_chars(input)
+        ship.Max_cargo = conv.str2ubyte(input)
+    }
+
+    sub do_next_galaxy() {
+        galaxy.nextgalaxy()
+        galaxy.travel_to(planet.number)
+        planet.display(false)
+    }
+
+    sub do_info() {
+        txt.print("\nSystem name (empty=current): ")
+        num_chars = txt.input_chars(input)
+        if num_chars {
+            ubyte current_planet = planet.number
+            if galaxy.search_closest_planet(input) {
+                planet.display(false)
+            } else {
+                txt.print(" Not found!")
+            }
+            galaxy.travel_to(current_planet)
+        } else {
+            planet.display(false)
+        }
+    }
+
+    sub do_local() {
+        galaxy.local_area()
+    }
+
+    sub do_show_market() {
+        market.display()
+        txt.print("\nFuel: ")
+        util.print_10s(ship.fuel)
+        txt.print("   Cargohold space: ")
+        txt.print_ub(ship.cargo_free())
+        txt.print("t\n")
+    }
+}
+
+ship {
+    const ubyte Max_fuel = 70
+    const ubyte Fuel_cost = 2
+    ubyte Max_cargo = 20
+
+    ubyte fuel = Max_fuel
+    uword cash = 1000               ; actually has to be 4 bytes for the ultra rich....
+    ubyte[17] cargohold = 0
+
+    sub init() {
+        memset(cargohold, len(cargohold), 0)
+    }
+
+    sub cargo_free() -> ubyte {
+        ubyte ci
+        ubyte total = 0
+        for ci in 0 to len(cargohold)-1 {
+            if market.units[ci]==0      ; tonnes only
+                total += cargohold[ci]
+        }
+        return Max_cargo - total
+    }
+}
+
+market {
+    ubyte[17] baseprices = [$13, $14, $41, $28, $53, $C4, $EB, $9A, $75, $4E, $7C, $B0, $20, $61, $AB, $2D, $35]
+    byte[17] gradients = [-$02, -$01, -$03, -$05, -$05, $08, $1D, $0E, $06, $01, $0d, -$09, -$01, -$01, -$02, -$01, $0F]
+    ubyte[17] basequants = [$06, $0A, $02, $E2, $FB, $36, $08, $38, $28, $11, $1D, $DC, $35, $42, $37, $FA, $C0]
+    ubyte[17] maskbytes = [$01, $03, $07, $1F, $0F, $03, $78, $03, $07, $1F, $07, $3F, $03, $07, $1F, $0F, $07]
+    ubyte[17] units = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 2, 0]
+    str[17] names = ["Food", "Textiles", "Radioactives", "Slaves", "Liquor/Wines", "Luxuries", "Narcotics", "Computers",
+                     "Machinery", "Alloys", "Firearms", "Furs", "Minerals", "Gold", "Platinum", "Gem-Stones", "Alien Items"]
+    str[3] unitnames = ["t", "kg", "g"]
+
+    ubyte[17] current_quantity = 0
+    uword[17] current_price = 0
+
+    sub init(ubyte fluct) {
+        ; Prices and availabilities are influenced by the planet's economy type
+        ; (0-7) and a random "fluctuation" byte that was kept within the saved
+        ; commander position to keep the market prices constant over gamesaves.
+        ; Availabilities must be saved with the game since the player alters them
+        ; by buying (and selling(?))
+        ;
+        ; Almost all operations are one byte only and overflow "errors" are
+        ; extremely frequent and exploited.
+        ;
+        ; Trade Item prices are held internally in a single byte=true value/4.
+        ; The decimal point in prices is introduced only when printing them.
+        ; Internally, all prices are integers.
+        ; The player's cash is held in four bytes.
+        ubyte ci
+        for ci in 0 to len(names)-1 {
+            word product
+            byte changing
+            product = planet.economy as word * gradients[ci]
+            changing = fluct & maskbytes[ci]  as byte
+            ubyte q = (basequants[ci] as word + changing - product) as ubyte
+            if q & $80
+                q = 0  ; clip to positive 8-bit
+            current_quantity[ci] = q & $3f
+            q = (baseprices[ci] + changing + product) as ubyte
+            current_price[ci] = q * $0004
+        }
+        current_quantity[16] = 0        ; force nonavailability of Alien Items
+    }
+
+    sub display() {
+        ubyte ci
+        txt.chrout('\n')
+        planet.print_name_uppercase()
+        txt.print(" trade market:\n    COMMODITY / PRICE / AVAIL / IN HOLD\n")
+        for ci in 0 to len(names)-1 {
+            util.print_right(13, names[ci])
+            txt.print("   ")
+            util.print_10s(current_price[ci])
+            txt.print("  ")
+            txt.print_ub(current_quantity[ci])
+            txt.print(unitnames[units[ci]])
+            txt.print("   ")
+            txt.print_ub(ship.cargohold[ci])
+            txt.chrout('\n')
+        }
+    }
+
+    sub match(uword nameptr) -> ubyte {
+        ubyte ci
+        for ci in 0 to len(names)-1 {
+            if util.prefix_matches(nameptr, names[ci])
+                return ci
+        }
+        return 255
+    }
+}
+
+galaxy {
+    const uword GALSIZE = 256
+    const uword base0 = $5A4A       ; seeds for the first galaxy
+    const uword base1 = $0248
+    const uword base2 = $B753
+
+    str pn_pairs = "..lexegezacebisousesarmaindirea.eratenberalavetiedorquanteisrion"
+
+    ubyte number
+
+    uword[3] seed
+
+    sub init(ubyte galaxynum) {
+        number = 1
+        planet.number = 255
+        seed = [base0, base1, base2]
+        repeat galaxynum-1 {
+            nextgalaxy()
+        }
+    }
+
+    sub nextgalaxy() {
+        seed = [twist(seed[0]), twist(seed[1]), twist(seed[2])]
+        number++
+        if number==9
+            number = 1
+    }
+
+    sub travel_to(ubyte system) {
+        init(number)
+        generate_next_planet()   ; always at least planet 0  (separate to avoid repeat ubyte overflow)
+        repeat system {
+            generate_next_planet()
+        }
+        planet.name = make_current_planet_name()
+        init_market_for_planet()
+    }
+
+    sub init_market_for_planet() {
+        market.init(lsb(seed[0])+msb(seed[2]))
+    }
+
+    sub search_closest_planet(uword nameptr) -> ubyte {
+        ubyte x = planet.x
+        ubyte y = planet.y
+        ubyte current_planet_num = planet.number
+
+        init(number)
+        ubyte found = false
+        ubyte current_closest_pi
+        ubyte current_distance = 127
+        ubyte pi
+        for pi in 0 to 255 {
+            generate_next_planet()
+            planet.name = make_current_planet_name()
+            if util.prefix_matches(nameptr, planet.name) {
+                ubyte distance = planet.distance(x, y)
+                if distance < current_distance {
+                    current_distance = distance
+                    current_closest_pi = pi
+                    found = true
+                }
+            }
+        }
+
+        if found
+            travel_to(current_closest_pi)
+        else
+            travel_to(current_planet_num)
+
+        return found
+    }
+
+    sub local_area() {
+        ubyte current_planet = planet.number
+        ubyte px = planet.x
+        ubyte py = planet.y
+        ubyte pn = 0
+
+        init(number)
+        txt.print("\nGalaxy #")
+        txt.print_ub(number)
+        txt.print(" - systems in vicinity:\n")
+        do {
+            generate_next_planet()
+            ubyte distance = planet.distance(px, py)
+            if distance <= ship.Max_fuel {
+                if distance <= ship.fuel
+                    txt.chrout('*')
+                else
+                    txt.chrout('-')
+                txt.chrout(' ')
+                planet.name = make_current_planet_name()
+                planet.display(true)
+                txt.print(" (")
+                util.print_10s(distance)
+                txt.print(" LY)\n")
+            }
+            pn++
+        } until pn==0
+
+        travel_to(current_planet)
+    }
+
+    ubyte pn_pair1
+    ubyte pn_pair2
+    ubyte pn_pair3
+    ubyte pn_pair4
+    ubyte longname
+
+    sub generate_next_planet() {
+        determine_planet_properties()
+        longname = lsb(seed[0]) & 64
+
+        ; Always four iterations of random number
+        pn_pair1 = (msb(seed[2]) & 31) * 2
+        tweakseed()
+        pn_pair2 = (msb(seed[2]) & 31) * 2
+        tweakseed()
+        pn_pair3 = (msb(seed[2]) & 31) * 2
+        tweakseed()
+        pn_pair4 = (msb(seed[2]) & 31) * 2
+        tweakseed()
+    }
+
+    sub make_current_planet_name() -> str {
+        ubyte ni = 0
+        str name = "         "    ; max 8
+        if pn_pairs[pn_pair1] != '.' {
+            name[ni] = pn_pairs[pn_pair1]
+            ni++
+        }
+        if pn_pairs[pn_pair1+1] != '.' {
+            name[ni] = pn_pairs[pn_pair1+1]
+            ni++
+        }
+        if pn_pairs[pn_pair2] != '.' {
+            name[ni] = pn_pairs[pn_pair2]
+            ni++
+        }
+        if pn_pairs[pn_pair2+1] != '.' {
+            name[ni] = pn_pairs[pn_pair2+1]
+            ni++
+        }
+        if pn_pairs[pn_pair3] != '.' {
+            name[ni] = pn_pairs[pn_pair3]
+            ni++
+        }
+        if pn_pairs[pn_pair3+1] != '.' {
+            name[ni] = pn_pairs[pn_pair3+1]
+            ni++
+        }
+
+        if longname {
+            if pn_pairs[pn_pair4] != '.' {
+                name[ni] = pn_pairs[pn_pair4]
+                ni++
+            }
+            if pn_pairs[pn_pair4+1] != '.' {
+                name[ni] = pn_pairs[pn_pair4+1]
+                ni++
+            }
+        }
+
+        name[ni] = 0
+        return name
+    }
+
+    sub determine_planet_properties() {
+        ; create the planet's characteristics
+        planet.number++
+        planet.x = msb(seed[1])
+        planet.y = msb(seed[0])
+        planet.govtype = lsb(seed[1]) >> 3 & 7  ; bits 3,4 &5 of w1
+        planet.economy = msb(seed[0]) & 7  ; bits 8,9 &A of w0
+        if planet.govtype <= 1
+            planet.economy = (planet.economy | 2)
+        planet.techlevel = (msb(seed[1]) & 3) + (planet.economy ^ 7)
+        planet.techlevel += planet.govtype >> 1
+        if planet.govtype & 1
+            planet.techlevel++
+        planet.population = 4 * planet.techlevel + planet.economy
+        planet.population += planet.govtype + 1
+        planet.productivity = ((planet.economy ^ 7) + 3) * (planet.govtype + 4)
+        planet.productivity *= planet.population * 8
+        ubyte seed2_msb = msb(seed[2])
+        planet.radius = mkword((seed2_msb & 15) + 11, planet.x)
+        planet.species_is_alien = lsb(seed[2]) & 128       ; bit 7 of w2_lo
+        if planet.species_is_alien {
+            planet.species_size = (seed2_msb >> 2) & 7      ; bits 2-4 of w2_hi
+            planet.species_color = seed2_msb >> 5           ; bits 5-7 of w2_hi
+            planet.species_look = (seed2_msb ^ msb(seed[1])) & 7   ;bits 0-2 of (w0_hi EOR w1_hi)
+            planet.species_kind = (planet.species_look + (seed2_msb & 3)) & 7      ;Add bits 0-1 of w2_hi to A from previous step, and take bits 0-2 of the result
+        }
+
+        planet.goatsoup_seed = [lsb(seed[1]), msb(seed[1]), lsb(seed[2]), seed2_msb]
+    }
+
+    sub tweakseed() {
+        uword temp = seed[0] + seed[1] + seed[2]
+        seed[0] = seed[1]
+        seed[1] = seed[2]
+        seed[2] = temp
+    }
+
+    sub twist(uword x) -> uword {
+        ubyte xh = msb(x)
+        ubyte xl = lsb(x)
+        rol(xh)
+        rol(xl)
+        return mkword(xh, xl)
+    }
+
+    sub debug_seed() {
+        txt.print("\ngalaxy #")
+        txt.print_ub(number)
+        txt.print("\ngalaxy seed0=")
+        txt.print_uwhex(galaxy.seed[0], true)
+        txt.print("\ngalaxy seed1=")
+        txt.print_uwhex(galaxy.seed[1], true)
+        txt.print("\ngalaxy seed2=")
+        txt.print_uwhex(galaxy.seed[2], true)
+        txt.chrout('\n')
+    }
+}
+
+planet {
+    %option force_output
+
+    str[] species_sizes = ["Large", "Fierce", "Small"]
+    str[] species_colors = ["Green", "Red", "Yellow", "Blue", "Black", "Harmless"]
+    str[] species_looks = ["Slimy", "Bug-Eyed", "Horned", "Bony", "Fat", "Furry"]
+    str[] species_kinds = ["Rodents", "Frogs", "Lizards", "Lobsters", "Birds", "Humanoids", "Felines", "Insects"]
+    str[] govnames = ["Anarchy", "Feudal", "Multi-gov", "Dictatorship", "Communist", "Confederacy", "Democracy", "Corporate State"]
+    str[] econnames = ["Rich Industrial", "Average Industrial", "Poor Industrial", "Mainly Industrial",
+                       "Mainly Agricultural", "Rich Agricultural", "Average Agricultural", "Poor Agricultural"]
+
+    str[] words81 = ["fabled", "notable", "well known", "famous", "noted"]
+    str[] words82 = ["very", "mildly", "most", "reasonably", ""]
+    str[] words83 = ["ancient", "\x95", "great", "vast", "pink"]
+    str[] words84 = ["\x9E \x9D plantations", "mountains", "\x9C", "\x94 forests", "oceans"]
+    str[] words85 = ["shyness", "silliness", "mating traditions", "loathing of \x86", "love for \x86"]
+    str[] words86 = ["food blenders", "tourists", "poetry", "discos", "\x8E"]
+    str[] words87 = ["talking tree", "crab", "bat", "lobst", "\xB2"]
+    str[] words88 = ["beset", "plagued", "ravaged", "cursed", "scourged"]
+    str[] words89 = ["\x96 civil war", "\x9B \x98 \x99s", "a \x9B disease", "\x96 earthquakes", "\x96 solar activity"]
+    str[] words8A = ["its \x83 \x84", "the \xB1 \x98 \x99", "its inhabitants' \x9A \x85", "\xA1", "its \x8D \x8E"]
+    str[] words8B = ["juice", "brandy", "water", "brew", "gargle blasters"]
+    str[] words8C = ["\xB2", "\xB1 \x99", "\xB1 \xB2", "\xB1 \x9B", "\x9B \xB2"]
+    str[] words8D = ["fabulous", "exotic", "hoopy", "unusual", "exciting"]
+    str[] words8E = ["cuisine", "night life", "casinos", "sit coms", " \xA1 "]
+    str[] words8F = ["\xB0", "The planet \xB0", "The world \xB0", "This planet", "This world"]
+    str[] words90 = ["n unremarkable", " boring", " dull", " tedious", " revolting"]
+    str[] words91 = ["planet", "world", "place", "little planet", "dump"]
+    str[] words92 = ["wasp", "moth", "grub", "ant", "\xB2"]
+    str[] words93 = ["poet", "arts graduate", "yak", "snail", "slug"]
+    str[] words94 = ["tropical", "dense", "rain", "impenetrable", "exuberant"]
+    str[] words95 = ["funny", "wierd", "unusual", "strange", "peculiar"]
+    str[] words96 = ["frequent", "occasional", "unpredictable", "dreadful", "deadly"]
+    str[] words97 = ["\x82 \x81 for \x8A", "\x82 \x81 for \x8A and \x8A", "\x88 by \x89", "\x82 \x81 for \x8A but \x88 by \x89", "a\x90 \x91"]
+    str[] words98 = ["\x9B", "mountain", "edible", "tree", "spotted"]
+    str[] words99 = ["\x9F", "\xA0", "\x87oid", "\x93", "\x92"]
+    str[] words9A = ["ancient", "exceptional", "eccentric", "ingrained", "\x95"]
+    str[] words9B = ["killer", "deadly", "evil", "lethal", "vicious"]
+    str[] words9C = ["parking meters", "dust clouds", "ice bergs", "rock formations", "volcanoes"]
+    str[] words9D = ["plant", "tulip", "banana", "corn", "\xB2weed"]
+    str[] words9E = ["\xB2", "\xB1 \xB2", "\xB1 \x9B", "inhabitant", "\xB1 \xB2"]
+    str[] words9F = ["shrew", "beast", "bison", "snake", "wolf"]
+    str[] wordsA0 = ["leopard", "cat", "monkey", "goat", "fish"]
+    str[] wordsA1 = ["\x8C \x8B", "\xB1 \x9F \xA2", "its \x8D \xA0 \xA2", "\xA3 \xA4", "\x8C \x8B"]
+    str[] wordsA2 = ["meat", "cutlet", "steak", "burgers", "soup"]
+    str[] wordsA3 = ["ice", "mud", "Zero-G", "vacuum", "\xB1 ultra"]
+    str[] wordsA4 = ["hockey", "cricket", "karate", "polo", "tennis"]
+
+    uword[] wordlists = [
+        words81, words82, words83, words84, words85, words86, words87, words88,
+        words89, words8A, words8B, words8C, words8D, words8E, words8F, words90,
+        words91, words92, words93, words94, words95, words96, words97, words98,
+        words99, words9A, words9B, words9C, words9D, words9E, words9F, wordsA0,
+        wordsA1, wordsA2, wordsA3, wordsA4]
+
+    str pairs0 = "abouseitiletstonlonuthnoallexegezacebisousesarmaindirea.eratenbe"
+
+    ubyte[4] goatsoup_rnd = [0, 0, 0, 0]
+    ubyte[4] goatsoup_seed = [0, 0, 0, 0]
+
+    str name = "        "       ; 8 max
+    ubyte number                ; starts at 0 in new galaxy, then increases by 1 for each generated planet
+    ubyte x
+    ubyte y
+    ubyte economy
+    ubyte govtype
+    ubyte techlevel
+    ubyte population
+    uword productivity
+    uword radius
+    ubyte species_is_alien      ; otherwise "Human Colonials"
+    ubyte species_size
+    ubyte species_color
+    ubyte species_look
+    ubyte species_kind
+
+    sub set_seed(uword s1, uword s2) {
+        goatsoup_seed[0] = lsb(s1)
+        goatsoup_seed[1] = msb(s1)
+        goatsoup_seed[2] = lsb(s2)
+        goatsoup_seed[3] = msb(s2)
+        reset_rnd()
+    }
+
+    sub reset_rnd() {
+        goatsoup_rnd[0] = goatsoup_seed[0]
+        goatsoup_rnd[1] = goatsoup_seed[1]
+        goatsoup_rnd[2] = goatsoup_seed[2]
+        goatsoup_rnd[3] = goatsoup_seed[3]
+    }
+
+    sub random_name() -> str {
+        ubyte ii
+        str name = "        "       ; 8 chars max
+        ubyte nx = 0
+        for ii in 0 to goatsoup_rnd_number() & 3 {
+            ubyte x = goatsoup_rnd_number() & $3e
+            if pairs0[x] != '.' {
+                name[nx] = pairs0[x]
+                nx++
+            }
+            if pairs0[x+1] != '.' {
+                name[nx] = pairs0[x+1]
+                nx++
+            }
+        }
+        name[nx] = 0
+        name[0] |= 32       ; uppercase first letter
+        return name
+    }
+
+    sub goatsoup_rnd_number() -> ubyte {
+        ubyte x = goatsoup_rnd[0] * 2
+        uword a = x as uword + goatsoup_rnd[2]
+        if goatsoup_rnd[0] > 127
+            a ++
+        goatsoup_rnd[0] = lsb(a)
+        goatsoup_rnd[2] = x
+        x = goatsoup_rnd[1]
+        ubyte ac = x + goatsoup_rnd[3] + msb(a)
+        goatsoup_rnd[1] = ac
+        goatsoup_rnd[3] = x
+        return ac
+    }
+
+    sub distance(ubyte px, ubyte py) -> ubyte {
+        uword ax
+        uword ay
+        if px>x
+            ax=px-x
+        else
+            ax=x-px
+        if py>y
+            ay=py-y
+        else
+            ay=y-py
+        ay /= 2
+        ubyte d = sqrt16(ax*ax + ay*ay)
+        if d>63
+            return 255
+        return d*4
+    }
+
+    sub soup() -> str {
+        str planet_result = " " * 160
+        uword[6] source_stack
+        ubyte stack_ptr = 0
+        str start_source = "\x8F is \x97."
+        uword source_ptr = &start_source
+        uword result_ptr = &planet_result
+
+        reset_rnd()
+        recursive_soup()
+        return planet_result
+
+        sub recursive_soup() {
+            repeat {
+                ubyte c = @(source_ptr)
+                source_ptr++
+                if c == $00 {
+                    @(result_ptr) = 0
+                    return
+                }
+                else if c <= $80 {
+                    @(result_ptr) = c
+                    result_ptr++
+                }
+                else {
+                    if c <= $a4 {
+                        ubyte rnr = goatsoup_rnd_number()
+                        ubyte wordNr = (rnr >= $33) + (rnr >= $66) + (rnr >= $99) + (rnr >= $CC)
+                        source_stack[stack_ptr] = source_ptr
+                        stack_ptr++
+                        source_ptr = getword(c, wordNr)
+                        ; TODO recursive call... should give error message... but hey since it's not doing that here now, lets exploit it
+                        recursive_soup()         ; RECURSIVE CALL
+                        stack_ptr--
+                        source_ptr = source_stack[stack_ptr]
+                    } else {
+                        if c == $b0 {
+                            @(result_ptr) = name[0] | 32
+                            result_ptr++
+                            concat_string(&name + 1)
+                        }
+                        else if c == $b1 {
+                            @(result_ptr) = name[0] | 32
+                            result_ptr++
+                            ubyte ni
+                            for ni in 1 to len(name) {
+                                ubyte cc = name[ni]
+                                if cc=='e' or cc=='o' or cc==0
+                                    break
+                                else {
+                                    @(result_ptr) = cc
+                                    result_ptr++
+                                }
+                            }
+                            @(result_ptr) = 'i'
+                            result_ptr++
+                            @(result_ptr) = 'a'
+                            result_ptr++
+                            @(result_ptr) = 'n'
+                            result_ptr++
+                        }
+                        else if c == $b2 {
+                            concat_string(random_name())
+                        }
+                        else {
+                            @(result_ptr) = c
+                            result_ptr++
+                        }
+                    }
+                }
+            }
+        }
+
+        sub concat_string(uword str_ptr) {
+            repeat {
+                ubyte c = @(str_ptr)
+                if c==0
+                    break
+                else {
+                    @(result_ptr) = c
+                    str_ptr++
+                    result_ptr++
+                }
+            }
+        }
+    }
+
+    sub display(ubyte compressed) {
+        if compressed {
+            print_name_uppercase()
+            txt.print(" TL:")
+            txt.print_ub(techlevel+1)
+            txt.chrout(' ')
+            txt.print(econnames[economy])
+            txt.chrout(' ')
+            txt.print(govnames[govtype])
+        } else {
+            txt.print("\n\nSystem: ")
+            print_name_uppercase()
+            txt.print("\nPosition: ")
+            txt.print_ub(x)
+            txt.chrout('\'')
+            txt.print_ub(y)
+            txt.chrout(' ')
+            txt.chrout('#')
+            txt.print_ub(number)
+            txt.print("\nEconomy: ")
+            txt.print(econnames[economy])
+            txt.print("\nGovernment: ")
+            txt.print(govnames[govtype])
+            txt.print("\nTech Level: ")
+            txt.print_ub(techlevel+1)
+            txt.print("\nTurnover: ")
+            txt.print_uw(productivity)
+            txt.print("\nRadius: ")
+            txt.print_uw(radius)
+            txt.print("\nPopulation: ")
+            txt.print_ub(population >> 3)
+            txt.print(" Billion\nSpecies: ")
+            if species_is_alien {
+                if species_size < len(species_sizes) {
+                    txt.print(species_sizes[species_size])
+                    txt.chrout(' ')
+                }
+                if species_color < len(species_colors) {
+                    txt.print(species_colors[species_color])
+                    txt.chrout(' ')
+                }
+                if species_look < len(species_looks) {
+                    txt.print(species_looks[species_look])
+                    txt.chrout(' ')
+                }
+                if species_kind < len(species_kinds) {
+                    txt.print(species_kinds[species_kind])
+                }
+            } else {
+                txt.print("Human Colonials")
+            }
+            txt.chrout('\n')
+            txt.print(soup())
+            txt.chrout('\n')
+        }
+    }
+
+    sub print_name_uppercase() {
+        ubyte c
+        for c in name
+            txt.chrout(c | 32)
+    }
+
+    asmsub getword(ubyte list @A, ubyte wordidx @Y) -> uword @AY {
+        %asm {{
+            sty  P8ZP_SCRATCH_REG
+            sec
+            sbc  #$81
+            asl  a
+            tay
+            lda  wordlists,y
+            sta  P8ZP_SCRATCH_W1
+            lda  wordlists+1,y
+            sta  P8ZP_SCRATCH_W1+1
+            lda  P8ZP_SCRATCH_REG
+            asl  a
+            tay
+            lda  (P8ZP_SCRATCH_W1),y
+            pha
+            iny
+            lda  (P8ZP_SCRATCH_W1),y
+            tay
+            pla
+            rts
+        }}
+    }
+}
+
+util {
+    sub prefix_matches(uword prefixptr, uword stringptr) -> ubyte {
+        ubyte ix=0
+        repeat {
+            ubyte pc = @(prefixptr)
+            ubyte sc = @(stringptr)
+            if pc == 0
+                return true
+            ; to lowercase for case insensitive compare:
+            pc &= 127
+            sc &= 127
+            if pc != sc
+                return false
+            prefixptr++
+            stringptr++
+        }
+        return false
+    }
+
+    sub print_right(ubyte width, uword string) {
+        repeat width - strlen(string) {
+            txt.chrout(' ')
+        }
+        txt.print(string)
+    }
+
+    asmsub print_10s(uword value @AY) clobbers(A, X, Y) {
+        %asm {{
+		    jsr  conv.uword2decimal
+		    lda  conv.uword2decimal.decTenThousands
+		    ldy  #0     ; have we started printing?
+		    cmp  #'0'
+		    beq  +
+		    jsr  c64.CHROUT
+		    iny
++           lda  conv.uword2decimal.decThousands
+		    cmp  #'0'
+            bne  +
+            cpy  #0
+            beq  ++
++           jsr  c64.CHROUT
+            iny
++           lda  conv.uword2decimal.decHundreds
+		    cmp  #'0'
+		    bne  +
+		    cpy  #0
+            beq  ++
++           jsr  c64.CHROUT
+            iny
++           lda  conv.uword2decimal.decTens
+            jsr  c64.CHROUT
+            lda  #'.'
+            jsr  c64.CHROUT
+            lda  conv.uword2decimal.decOnes
+            jsr  c64.CHROUT
+            rts
+        }}
+    }
+
+    asmsub testX() {
+        %asm {{
+            stx  _saveX
+            lda  #13
+            jsr  txt.chrout
+            lda  _saveX
+            jsr  txt.print_ub
+            lda  #13
+            jsr  txt.chrout
+            ldx  _saveX
+            rts
+_saveX      .byte 0
+        }}
+    }
+
+}

parser/antlr/prog8.g4

@@ -172,10 +172,10 @@ expression :
 	| left = expression EOL? bop = ('+' | '-' ) EOL? right = expression
 	| left = expression EOL? bop = ('<<' | '>>' ) EOL? right = expression
 	| left = expression EOL? bop = ('<' | '>' | '<=' | '>=') EOL? right = expression
-	| left = expression EOL? bop = ('==' | '!=') EOL? right = expression
 	| left = expression EOL? bop = '&' EOL? right = expression
 	| left = expression EOL? bop = '^' EOL? right = expression
 	| left = expression EOL? bop = '|' EOL? right = expression
+	| left = expression EOL? bop = ('==' | '!=') EOL? right = expression
 	| rangefrom = expression rto = ('to'|'downto') rangeto = expression ('step' rangestep = expression)?	// can't create separate rule due to mutual left-recursion
 	| left = expression EOL? bop = 'and' EOL? right = expression
 	| left = expression EOL? bop = 'or' EOL? right = expression