version 4.5

compiler/res/prog8lib/c64/floats.asm

@@ -355,19 +355,19 @@ mul_f		.proc
 		.pend
 
 neg_f		.proc
-		; -- push -flt back on stack
-		jsr  pop_float_fac1
-		stx  P8ZP_SCRATCH_REG
-		jsr  NEGOP
-		jmp  push_fac1_as_result
+		; -- toggle the sign bit on the stack
+		lda  P8ESTACK_HI+3,x
+		eor  #$80
+		sta  P8ESTACK_HI+3,x
+		rts
 		.pend
 
 abs_f		.proc
-		; -- push abs(float) on stack (as float)
-		jsr  pop_float_fac1
-		stx  P8ZP_SCRATCH_REG
-		jsr  ABS
-		jmp  push_fac1_as_result
+		; -- strip the sign bit on the stack
+		lda  P8ESTACK_HI+3,x
+		and  #$7f
+		sta  P8ESTACK_HI+3,x
+		rts
 		.pend
 
 equal_f		.proc

compiler/res/prog8lib/c64/floats.p8

@@ -207,8 +207,8 @@ sub  print_f  (float value) {
 		jsr  c64.CHROUT
 		iny
 		bne  -
-		ldx  floats_store_reg
-+		rts
++		ldx  floats_store_reg
+		rts
 	}}
 }
 

compiler/res/prog8lib/c64/graphics.p8

@@ -33,8 +33,8 @@ graphics {
         }
         word @zp d = 0
         ubyte positive_ix = true
-        word @zp dx = x2 - x1 as word
-        word @zp dy = y2 as word - y1 as word
+        word @zp dx = x2-x1
+        word @zp dy = y2-y1
         if dx < 0 {
             dx = -dx
             positive_ix = false

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
@@ -251,8 +251,7 @@ asmsub  init_system()  {
         sta  c64.COLOR
         lda  #0
         sta  c64.BGCOL0
-        tax
-        tay
+        jsr  disable_runstop_and_charsetswitch
         clc
         clv
         cli
@@ -270,6 +269,16 @@ asmsub  reset_system()  {
     }}
 }
 
+asmsub  disable_runstop_and_charsetswitch() {
+    %asm {{
+        lda  #$80
+        sta  657    ; disable charset switching
+        lda  #239
+        sta  808    ; disable run/stop key
+        rts
+    }}
+}
+
 asmsub  set_irqvec_excl() clobbers(A)  {
 	%asm {{
 		sei

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
 
 }
@@ -169,20 +169,18 @@ cx16 {
 ; ---- Commander X-16 additions on top of C64 kernal routines ----
 ; spelling of the names is taken from the Commander X-16 rom sources
 
-; TODO specify the correct clobbers for alle these functions, for simplicity all 3 regs are marked clobbered atm
-
 ; supported C128 additions
-romsub $ff4a = close_all()  clobbers(A,X,Y)
-romsub $ff59 = lkupla()  clobbers(A,X,Y)
-romsub $ff5c = lkupsa()  clobbers(A,X,Y)
+romsub $ff4a = close_all(ubyte device @A)  clobbers(A,X,Y)
+romsub $ff59 = lkupla(ubyte la @A)  clobbers(A,X,Y)
+romsub $ff5c = lkupsa(ubyte sa @Y)  clobbers(A,X,Y)
 romsub $ff5f = screen_set_mode(ubyte mode @A)  clobbers(A, X, Y) -> ubyte @Pc
 romsub $ff62 = screen_set_charset(ubyte charset @A, uword charsetptr @XY)  clobbers(A,X,Y)      ; incompatible with C128  dlchr()
-romsub $ff65 = pfkey()  clobbers(A,X,Y)
-romsub $ff6e = jsrfar()  clobbers(A,X,Y)
-romsub $ff74 = fetch()  clobbers(A,X,Y)
-romsub $ff77 = stash()  clobbers(A,X,Y)
-romsub $ff7a = cmpare()  clobbers(A,X,Y)
-romsub $ff7d = primm()  clobbers(A,X,Y)
+; not yet supported: romsub $ff65 = pfkey()  clobbers(A,X,Y)
+romsub $ff6e = jsrfar()
+romsub $ff74 = fetch(ubyte bank @X, ubyte index @Y)  clobbers(X) -> ubyte @A
+romsub $ff77 = stash(ubyte data @A, ubyte bank @X, ubyte index @Y)  clobbers(X)
+romsub $ff7a = cmpare(ubyte data @A, ubyte bank @X, ubyte index @Y)  clobbers(X)
+romsub $ff7d = primm()
 
 ; X16 additions
 romsub $ff44 = macptr()  clobbers(A,X,Y)
@@ -193,7 +191,9 @@ romsub $ff71 = mouse_scan()  clobbers(A, X, Y)
 romsub $ff53 = joystick_scan()  clobbers(A, X, Y)
 romsub $ff56 = joystick_get(ubyte joynr @A) -> ubyte @A, ubyte @X, ubyte @Y
 romsub $ff4d = clock_set_date_time()  clobbers(A, X, Y)      ; args: r0, r1, r2, r3L
-romsub $ff50 = clock_get_date_time()  clobbers(A)            ; outout args: r0, r1, r2, r3L
+romsub $ff50 = clock_get_date_time()  clobbers(A, X, Y)      ; outout args: r0, r1, r2, r3L
+
+; TODO specify the correct clobbers for alle these functions below, we now assume all 3 regs are clobbered
 
 ; high level graphics & fonts
 romsub $ff20 = GRAPH_init()  clobbers(A,X,Y)           ; uses vectors=r0

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 @@
-4.3
+4.5

compiler/src/prog8/ast/AstToSourceCode.kt

@@ -53,12 +53,14 @@ class AstToSourceCode(val output: (text: String) -> Unit, val program: Program):
     }
 
     override fun visit(expr: BinaryExpression) {
+        output("(")
         expr.left.accept(this)
         if(expr.operator.any { it.isLetter() })
             output(" ${expr.operator} ")
         else
             output(expr.operator)
         expr.right.accept(this)
+        output(")")
     }
 
     override fun visit(directive: Directive) {
@@ -85,7 +87,7 @@ class AstToSourceCode(val output: (text: String) -> Unit, val program: Program):
             DataType.ARRAY_W -> "word["
             DataType.ARRAY_F -> "float["
             DataType.STRUCT -> ""       // the name of the struct is enough
-            else -> "?????2"
+            else -> "?????"
         }
     }
 
@@ -113,7 +115,10 @@ class AstToSourceCode(val output: (text: String) -> Unit, val program: Program):
             VarDeclType.CONST -> output("const ")
             VarDeclType.MEMORY -> output("&")
         }
-        output(decl.struct?.name ?: "")
+
+        if(decl.datatype==DataType.STRUCT && decl.struct!=null)
+            output(decl.struct!!.name)
+
         output(datatypeString(decl.datatype))
         if(decl.arraysize!=null) {
             decl.arraysize!!.index.accept(this)
@@ -338,7 +343,7 @@ class AstToSourceCode(val output: (text: String) -> Unit, val program: Program):
         output("do ")
         untilLoop.body.accept(this)
         output(" until ")
-        untilLoop.untilCondition.accept(this)
+        untilLoop.condition.accept(this)
     }
 
     override fun visit(returnStmt: Return) {

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)
 
@@ -137,7 +146,15 @@ interface INameScope {
             }
             return null
         } else {
-            // unqualified name, find the scope the localContext is in, look in that first
+            // unqualified name
+            // special case: the do....until statement can also look INSIDE the anonymous scope
+            if(localContext.parent.parent is UntilLoop) {
+                val symbolFromInnerScope = (localContext.parent.parent as UntilLoop).body.getLabelOrVariable(scopedName[0])
+                if(symbolFromInnerScope!=null)
+                    return symbolFromInnerScope
+            }
+
+            // find the scope the localContext is in, look in that first
             var statementScope = localContext
             while(statementScope !is ParentSentinel) {
                 val localScope = statementScope.definingScope()
@@ -232,7 +249,7 @@ class Program(val name: String, val modules: MutableList<Module>): Node {
 
     override fun linkParents(parent: Node) {
         modules.forEach {
-            it.linkParents(this)
+            it.linkParents(namespace)
         }
     }
 
@@ -252,10 +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
@@ -282,6 +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) }
@@ -312,6 +334,14 @@ class GlobalNamespace(val modules: List<Module>): Node, INameScope {
                 }
             }
         }
+
+        // special case: the do....until statement can also look INSIDE the anonymous scope
+        if(localContext.parent.parent is UntilLoop) {
+            val symbolFromInnerScope = (localContext.parent.parent as UntilLoop).body.lookup(scopedName, localContext)
+            if(symbolFromInnerScope!=null)
+                return symbolFromInnerScope
+        }
+
         // lookup something from the module.
         return when (val stmt = localContext.definingModule().lookup(scopedName, localContext)) {
             is Label, is VarDecl, is Block, is Subroutine, is StructDecl -> stmt
@@ -326,6 +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

@@ -17,13 +17,13 @@ import kotlin.math.abs
 
 val associativeOperators = setOf("+", "*", "&", "|", "^", "or", "and", "xor", "==", "!=")
 val comparisonOperators = setOf("==", "!=", "<", ">", "<=", ">=")
-
+val augmentAssignmentOperators = setOf("+", "-", "/", "*", "**", "&", "|", "^", "<<", ">>")
 
 sealed class Expression: Node {
     abstract fun constValue(program: Program): NumericLiteralValue?
     abstract fun accept(visitor: IAstVisitor)
     abstract fun accept(visitor: AstWalker, parent: Node)
-    abstract fun referencesIdentifiers(vararg name: String): Boolean
+    abstract fun referencesIdentifier(vararg scopedName: String): Boolean
     abstract fun inferType(program: Program): InferredTypes.InferredType
 
     infix fun isSameAs(assigntarget: AssignTarget) = assigntarget.isSameAs(this)
@@ -85,7 +85,7 @@ class PrefixExpression(val operator: String, var expression: Expression, overrid
     override fun accept(visitor: IAstVisitor) = visitor.visit(this)
     override fun accept(visitor: AstWalker, parent: Node)= visitor.visit(this, parent)
 
-    override fun referencesIdentifiers(vararg name: String) = expression.referencesIdentifiers(*name)
+    override fun referencesIdentifier(vararg scopedName: String) = expression.referencesIdentifier(*scopedName)
     override fun inferType(program: Program): InferredTypes.InferredType {
         val inferred = expression.inferType(program)
         return when(operator) {
@@ -142,7 +142,7 @@ class BinaryExpression(var left: Expression, var operator: String, var right: Ex
     override fun accept(visitor: IAstVisitor) = visitor.visit(this)
     override fun accept(visitor: AstWalker, parent: Node)= visitor.visit(this, parent)
 
-    override fun referencesIdentifiers(vararg name: String) = left.referencesIdentifiers(*name) || right.referencesIdentifiers(*name)
+    override fun referencesIdentifier(vararg scopedName: String) = left.referencesIdentifier(*scopedName) || right.referencesIdentifier(*scopedName)
     override fun inferType(program: Program): InferredTypes.InferredType {
         val leftDt = left.inferType(program)
         val rightDt = right.inferType(program)
@@ -255,7 +255,7 @@ class ArrayIndexedExpression(var identifier: IdentifierReference,
     override fun accept(visitor: IAstVisitor) = visitor.visit(this)
     override fun accept(visitor: AstWalker, parent: Node)= visitor.visit(this, parent)
 
-    override fun referencesIdentifiers(vararg name: String) = identifier.referencesIdentifiers(*name)
+    override fun referencesIdentifier(vararg scopedName: String) = identifier.referencesIdentifier(*scopedName)
 
     override fun inferType(program: Program): InferredTypes.InferredType {
         val target = identifier.targetStatement(program.namespace)
@@ -291,7 +291,7 @@ class TypecastExpression(var expression: Expression, var type: DataType, val imp
     override fun accept(visitor: IAstVisitor) = visitor.visit(this)
     override fun accept(visitor: AstWalker, parent: Node)= visitor.visit(this, parent)
 
-    override fun referencesIdentifiers(vararg name: String) = expression.referencesIdentifiers(*name)
+    override fun referencesIdentifier(vararg scopedName: String) = expression.referencesIdentifier(*scopedName)
     override fun inferType(program: Program): InferredTypes.InferredType = InferredTypes.knownFor(type)
     override fun constValue(program: Program): NumericLiteralValue? {
         val cv = expression.constValue(program) ?: return null
@@ -322,7 +322,7 @@ data class AddressOf(var identifier: IdentifierReference, override val position:
     }
 
     override fun constValue(program: Program): NumericLiteralValue? = null
-    override fun referencesIdentifiers(vararg name: String) = false
+    override fun referencesIdentifier(vararg scopedName: String) = false
     override fun inferType(program: Program): InferredTypes.InferredType = InferredTypes.knownFor(DataType.UWORD)
     override fun accept(visitor: IAstVisitor) = visitor.visit(this)
     override fun accept(visitor: AstWalker, parent: Node)= visitor.visit(this, parent)
@@ -345,7 +345,7 @@ class DirectMemoryRead(var addressExpression: Expression, override val position:
     override fun accept(visitor: IAstVisitor) = visitor.visit(this)
     override fun accept(visitor: AstWalker, parent: Node)= visitor.visit(this, parent)
 
-    override fun referencesIdentifiers(vararg name: String) = false
+    override fun referencesIdentifier(vararg scopedName: String) = false
     override fun inferType(program: Program): InferredTypes.InferredType = InferredTypes.knownFor(DataType.UBYTE)
     override fun constValue(program: Program): NumericLiteralValue? = null
 
@@ -398,7 +398,7 @@ class NumericLiteralValue(val type: DataType,    // only numerical types allowed
         throw FatalAstException("can't replace here")
     }
 
-    override fun referencesIdentifiers(vararg name: String) = false
+    override fun referencesIdentifier(vararg scopedName: String) = false
     override fun constValue(program: Program) = this
 
     override fun accept(visitor: IAstVisitor) = visitor.visit(this)
@@ -498,7 +498,7 @@ class StringLiteralValue(val value: String,
         throw FatalAstException("can't replace here")
     }
 
-    override fun referencesIdentifiers(vararg name: String) = false
+    override fun referencesIdentifier(vararg scopedName: String) = false
     override fun constValue(program: Program): NumericLiteralValue? = null
     override fun accept(visitor: IAstVisitor) = visitor.visit(this)
     override fun accept(visitor: AstWalker, parent: Node)= visitor.visit(this, parent)
@@ -533,7 +533,7 @@ class ArrayLiteralValue(val type: InferredTypes.InferredType,     // inferred be
         replacement.parent = this
     }
 
-    override fun referencesIdentifiers(vararg name: String) = value.any { it.referencesIdentifiers(*name) }
+    override fun referencesIdentifier(vararg scopedName: String) = value.any { it.referencesIdentifier(*scopedName) }
     override fun constValue(program: Program): NumericLiteralValue? = null
     override fun accept(visitor: IAstVisitor) = visitor.visit(this)
     override fun accept(visitor: AstWalker, parent: Node)= visitor.visit(this, parent)
@@ -569,10 +569,17 @@ class ArrayLiteralValue(val type: InferredTypes.InferredType,     // inferred be
         val dts = datatypesInArray.map { it.typeOrElse(DataType.STRUCT) }
         return when {
             DataType.FLOAT in dts -> InferredTypes.InferredType.known(DataType.ARRAY_F)
+            DataType.STR in dts -> InferredTypes.InferredType.known(DataType.ARRAY_UW)
             DataType.WORD in dts -> InferredTypes.InferredType.known(DataType.ARRAY_W)
             DataType.UWORD in dts -> InferredTypes.InferredType.known(DataType.ARRAY_UW)
             DataType.BYTE in dts -> InferredTypes.InferredType.known(DataType.ARRAY_B)
             DataType.UBYTE in dts -> InferredTypes.InferredType.known(DataType.ARRAY_UB)
+            DataType.ARRAY_UW in dts ||
+                DataType.ARRAY_W in dts ||
+                DataType.ARRAY_UB in dts ||
+                DataType.ARRAY_B in dts ||
+                DataType.ARRAY_F in dts ||
+                DataType.STRUCT in dts -> InferredTypes.InferredType.known(DataType.ARRAY_UW)
             else -> InferredTypes.InferredType.unknown()
         }
     }
@@ -631,7 +638,7 @@ class RangeExpr(var from: Expression,
     override fun accept(visitor: IAstVisitor) = visitor.visit(this)
     override fun accept(visitor: AstWalker, parent: Node)= visitor.visit(this, parent)
 
-    override fun referencesIdentifiers(vararg name: String): Boolean  = from.referencesIdentifiers(*name) || to.referencesIdentifiers(*name)
+    override fun referencesIdentifier(vararg scopedName: String): Boolean  = from.referencesIdentifier(*scopedName) || to.referencesIdentifier(*scopedName)
     override fun inferType(program: Program): InferredTypes.InferredType {
         val fromDt=from.inferType(program)
         val toDt=to.inferType(program)
@@ -744,8 +751,8 @@ data class IdentifierReference(val nameInSource: List<String>, override val posi
     override fun accept(visitor: IAstVisitor) = visitor.visit(this)
     override fun accept(visitor: AstWalker, parent: Node)= visitor.visit(this, parent)
 
-    override fun referencesIdentifiers(vararg name: String): Boolean =
-            nameInSource.size==name.size && nameInSource.toTypedArray().contentEquals(name)
+    override fun referencesIdentifier(vararg scopedName: String): Boolean =
+            nameInSource.size==scopedName.size && nameInSource.toTypedArray().contentEquals(scopedName)
 
     override fun inferType(program: Program): InferredTypes.InferredType {
         return when (val targetStmt = targetStatement(program.namespace)) {
@@ -767,6 +774,18 @@ data class IdentifierReference(val nameInSource: List<String>, override val posi
             else -> throw FatalAstException("requires a reference value")
         }
     }
+
+    fun firstStructVarName(namespace: INameScope): String? {
+        // take the name of the first struct member of the structvariable instead
+        // if it's just a regular variable, return null.
+        val struct = memberOfStruct(namespace) ?: return null
+        val decl = targetVarDecl(namespace)!!
+        val firstStructMember = struct.nameOfFirstMember()
+        // find the flattened var that belongs to this first struct member
+        val firstVarName = listOf(decl.name, firstStructMember)
+        val firstVar = definingScope().lookup(firstVarName, this) as VarDecl
+        return firstVar.name
+    }
 }
 
 class FunctionCall(override var target: IdentifierReference,
@@ -833,7 +852,7 @@ class FunctionCall(override var target: IdentifierReference,
     override fun accept(visitor: IAstVisitor) = visitor.visit(this)
     override fun accept(visitor: AstWalker, parent: Node)= visitor.visit(this, parent)
 
-    override fun referencesIdentifiers(vararg name: String): Boolean = target.referencesIdentifiers(*name) || args.any{it.referencesIdentifiers(*name)}
+    override fun referencesIdentifier(vararg scopedName: String): Boolean = target.referencesIdentifier(*scopedName) || args.any{it.referencesIdentifier(*scopedName)}
 
     override fun inferType(program: Program): InferredTypes.InferredType {
         val constVal = constValue(program ,false)
@@ -853,6 +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

@@ -334,8 +334,8 @@ internal class AstChecker(private val program: Program,
     }
 
     override fun visit(untilLoop: UntilLoop) {
-        if(untilLoop.untilCondition.inferType(program).typeOrElse(DataType.STRUCT) !in IntegerDatatypes)
-            errors.err("condition value should be an integer type", untilLoop.untilCondition.position)
+        if(untilLoop.condition.inferType(program).typeOrElse(DataType.STRUCT) !in IntegerDatatypes)
+            errors.err("condition value should be an integer type", untilLoop.condition.position)
         super.visit(untilLoop)
     }
 
@@ -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)
                 }
             }
         }
@@ -376,6 +374,9 @@ internal class AstChecker(private val program: Program,
                         if (sourceVar?.struct != null) {
                             if (sourceVar.struct !== targetVar.struct)
                                 errors.err("assignment of different struct types", assignment.position)
+                        } else if(sourceVar?.isArray==true) {
+                            if((sourceVar.value as ArrayLiteralValue).value.size != targetVar.struct?.numberOfElements)
+                                errors.err("number of elements doesn't match struct definition", sourceVar.position)
                         }
                     }
                 }
@@ -383,7 +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
@@ -443,12 +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,
@@ -476,7 +474,7 @@ internal class AstChecker(private val program: Program,
         fun err(msg: String, position: Position?=null) = errors.err(msg, position ?: decl.position)
 
         // the initializer value can't refer to the variable itself (recursive definition)
-        if(decl.value?.referencesIdentifiers(decl.name) == true || decl.arraysize?.index?.referencesIdentifiers(decl.name) == true)
+        if(decl.value?.referencesIdentifier(decl.name) == true || decl.arraysize?.index?.referencesIdentifier(decl.name) == true)
             err("recursive var declaration")
 
         // CONST can only occur on simple types (byte, word, float)
@@ -629,6 +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)
     }
 
@@ -709,7 +715,7 @@ internal class AstChecker(private val program: Program,
                     err("this directive may only occur in a block or at module level")
                 if(directive.args.isEmpty())
                     err("missing option directive argument(s)")
-                else if(directive.args.map{it.name in setOf("enable_floats", "force_output")}.any { !it })
+                else if(directive.args.map{it.name in setOf("enable_floats", "force_output", "no_sysinit")}.any { !it })
                     err("invalid option directive argument(s)")
             }
             "%target" -> {
@@ -742,9 +748,20 @@ internal class AstChecker(private val program: Program,
             checkValueTypeAndRangeArray(array.type.typeOrElse(DataType.STRUCT), null, arrayspec, array)
         }
 
-        if(!array.value.all { it is NumericLiteralValue || it is AddressOf || it is StringLiteralValue }) {
-            // TODO for now, array literals have to consist of all compile time constant values...
-            errors.err("array literal doesn't consist of only compile time constant values", array.position)
+        fun isPassByReferenceElement(e: Expression): Boolean {
+            if(e is IdentifierReference) {
+                val decl = e.targetVarDecl(program.namespace)!!
+                return decl.datatype in PassByReferenceDatatypes
+            }
+            return e is StringLiteralValue
+        }
+
+        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)
@@ -774,6 +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)
@@ -813,13 +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) {
@@ -879,7 +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/AstWalker.kt

@@ -82,6 +82,7 @@ interface IAstModification {
 
     class SwapOperands(val expr: BinaryExpression): IAstModification {
         override fun perform() {
+            require(expr.operator in associativeOperators)
             val tmp = expr.left
             expr.left = expr.right
             expr.right = tmp
@@ -228,6 +229,7 @@ abstract class AstWalker {
         track(before(decl, parent), decl, parent)
         decl.value?.accept(this, decl)
         decl.arraysize?.accept(this, decl)
+        decl.struct?.accept(this, decl)
         track(after(decl, parent), decl, parent)
     }
 
@@ -348,7 +350,7 @@ abstract class AstWalker {
 
     fun visit(untilLoop: UntilLoop, parent: Node) {
         track(before(untilLoop, parent), untilLoop, parent)
-        untilLoop.untilCondition.accept(this, untilLoop)
+        untilLoop.condition.accept(this, untilLoop)
         untilLoop.body.accept(this, untilLoop)
         track(after(untilLoop, parent), untilLoop, parent)
     }

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

@@ -33,6 +33,7 @@ interface IAstVisitor {
     fun visit(decl: VarDecl) {
         decl.value?.accept(this)
         decl.arraysize?.accept(this)
+        decl.struct?.accept(this)
     }
 
     fun visit(subroutine: Subroutine) {
@@ -115,7 +116,7 @@ interface IAstVisitor {
     }
 
     fun visit(untilLoop: UntilLoop) {
-        untilLoop.untilCondition.accept(this)
+        untilLoop.condition.accept(this)
         untilLoop.body.accept(this)
     }
 

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)
-        if(valueType.istype(DataType.STRUCT) && targetType.istype(DataType.STRUCT)) {
-            val assignments = if (assignment.value is ArrayLiteralValue) {
-                flattenStructAssignmentFromStructLiteral(assignment, program)    //  'structvar = [ ..... ] '
+        var assignments = emptyList<Assignment>()
+
+        if(targetType.istype(DataType.STRUCT) && (valueType.istype(DataType.STRUCT) || valueType.typeOrElse(DataType.STRUCT) in ArrayDatatypes )) {
+            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)!!
@@ -179,26 +245,47 @@ internal class StatementReorderer(val program: Program) : AstWalker() {
         when (structAssignment.value) {
             is IdentifierReference -> {
                 val sourceVar = (structAssignment.value as IdentifierReference).targetVarDecl(program.namespace)!!
-                if (sourceVar.struct == null)
-                    throw FatalAstException("can only assign arrays or structs to structs")
-                // struct memberwise copy
-                val sourceStruct = sourceVar.struct!!
-                if(sourceStruct!==targetVar.struct) {
-                    // structs are not the same in assignment
-                    return listOf()     // error will be printed elsewhere
-                }
-                return struct.statements.zip(sourceStruct.statements).map { member ->
-                    val targetDecl = member.first as VarDecl
-                    val sourceDecl = member.second as VarDecl
-                    if(targetDecl.name != sourceDecl.name)
-                        throw FatalAstException("struct member mismatch")
-                    val mangled = mangledStructMemberName(identifierName, targetDecl.name)
-                    val idref = IdentifierReference(listOf(mangled), structAssignment.position)
-                    val sourcemangled = mangledStructMemberName(sourceVar.name, sourceDecl.name)
-                    val sourceIdref = IdentifierReference(listOf(sourcemangled), structAssignment.position)
-                    val assign = Assignment(AssignTarget(idref, null, null, structAssignment.position), sourceIdref, member.second.position)
-                    assign.linkParents(structAssignment)
-                    assign
+                when {
+                    sourceVar.struct!=null -> {
+                        // struct memberwise copy
+                        val sourceStruct = sourceVar.struct!!
+                        if(sourceStruct!==targetVar.struct) {
+                            // structs are not the same in assignment
+                            return listOf()     // error will be printed elsewhere
+                        }
+                        if(struct.statements.size!=sourceStruct.statements.size)
+                            return listOf()     // error will be printed elsewhere
+                        return struct.statements.zip(sourceStruct.statements).map { member ->
+                            val targetDecl = member.first as VarDecl
+                            val sourceDecl = member.second as VarDecl
+                            if(targetDecl.name != sourceDecl.name)
+                                throw FatalAstException("struct member mismatch")
+                            val mangled = mangledStructMemberName(identifierName, targetDecl.name)
+                            val idref = IdentifierReference(listOf(mangled), structAssignment.position)
+                            val sourcemangled = mangledStructMemberName(sourceVar.name, sourceDecl.name)
+                            val sourceIdref = IdentifierReference(listOf(sourcemangled), structAssignment.position)
+                            val assign = Assignment(AssignTarget(idref, null, null, structAssignment.position), sourceIdref, member.second.position)
+                            assign.linkParents(structAssignment)
+                            assign
+                        }
+                    }
+                    sourceVar.isArray -> {
+                        val array = (sourceVar.value as ArrayLiteralValue).value
+                        if(struct.statements.size!=array.size)
+                            return listOf()     // error will be printed elsewhere
+                        return struct.statements.zip(array).map {
+                            val decl = it.first as VarDecl
+                            val mangled = mangledStructMemberName(identifierName, decl.name)
+                            val targetName = IdentifierReference(listOf(mangled), structAssignment.position)
+                            val target = AssignTarget(targetName, null, null, structAssignment.position)
+                            val assign = Assignment(target, it.second, structAssignment.position)
+                            assign.linkParents(structAssignment)
+                            assign
+                        }
+                    }
+                    else -> {
+                        throw FatalAstException("can only assign arrays or structs to structs")
+                    }
                 }
             }
             is ArrayLiteralValue -> {

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
 
@@ -26,20 +25,42 @@ class VerifyFunctionArgTypes(val program: Program) : IAstVisitor {
     }
 
     companion object {
+
+        private fun argTypeCompatible(argDt: DataType, paramDt: DataType): Boolean {
+            if(argDt==paramDt)
+                return true
+
+            // there are some exceptions that are considered compatible, such as STR <> UWORD
+            if(argDt==DataType.STR && paramDt==DataType.UWORD ||
+                    argDt==DataType.UWORD && paramDt==DataType.STR)
+                return true
+
+            return false
+        }
+
         fun checkTypes(call: IFunctionCall, scope: INameScope, program: Program): String? {
             val argtypes = call.args.map { it.inferType(program).typeOrElse(DataType.STRUCT) }
             val target = call.target.targetStatement(scope)
             if (target is Subroutine) {
-                // asmsub types are not checked specifically at this time
                 if(call.args.size != target.parameters.size)
                     return "invalid number of arguments"
                 val paramtypes = target.parameters.map { it.type }
-                val mismatch = argtypes.zip(paramtypes).indexOfFirst { it.first != it.second}
+                val mismatch = argtypes.zip(paramtypes).indexOfFirst { !argTypeCompatible(it.first, it.second) }
                 if(mismatch>=0) {
                     val actual = argtypes[mismatch].toString()
                     val expected = paramtypes[mismatch].toString()
                     return "argument ${mismatch + 1} type mismatch, was: $actual expected: $expected"
                 }
+                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)
@@ -47,7 +68,8 @@ class VerifyFunctionArgTypes(val program: Program) : IAstVisitor {
                     return "invalid number of arguments"
                 val paramtypes = func.parameters.map { it.possibleDatatypes }
                 for (x in argtypes.zip(paramtypes).withIndex()) {
-                    if (x.value.first !in x.value.second) {
+                    val anyCompatible = x.value.second.any { argTypeCompatible(x.value.first, it) }
+                    if (!anyCompatible) {
                         val actual = x.value.first.toString()
                         val expected = x.value.second.toString()
                         return "argument ${x.index + 1} type mismatch, was: $actual expected: $expected"

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

@@ -5,6 +5,7 @@ import prog8.ast.base.*
 import prog8.ast.expressions.*
 import prog8.ast.processing.AstWalker
 import prog8.ast.processing.IAstVisitor
+import prog8.compiler.target.CompilationTarget
 
 
 sealed class Statement : Node {
@@ -56,6 +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
@@ -214,8 +216,9 @@ open class VarDecl(val type: VarDeclType,
                 DataType.UWORD -> DataType.ARRAY_UW
                 DataType.WORD -> DataType.ARRAY_W
                 DataType.FLOAT -> DataType.ARRAY_F
+                DataType.STR -> DataType.ARRAY_UW       // use memory address of the string instead
                 else -> {
-                    datatypeErrors.add(SyntaxError("array can only contain bytes/words/floats", position))
+                    datatypeErrors.add(SyntaxError("array can only contain bytes/words/floats/strings(ptrs)", position))
                     DataType.ARRAY_UB
                 }
             }
@@ -232,7 +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
     }
@@ -301,6 +305,8 @@ class ArrayIndex(var index: Expression, override val position: Position) : Node
     }
 
     fun constIndex() = (index as? NumericLiteralValue)?.number?.toInt()
+
+    infix fun isSameAs(other: ArrayIndex) = index.isSameAs(other.index)
 }
 
 open class Assignment(var target: AssignTarget, var value: Expression, override val position: Position) : Statement() {
@@ -391,8 +397,8 @@ data class AssignTarget(var identifier: IdentifierReference?,
 
     override fun replaceChildNode(node: Node, replacement: Node) {
         when {
-            node===identifier -> identifier = replacement as IdentifierReference
-            node===arrayindexed -> arrayindexed = replacement as ArrayIndexedExpression
+            node === identifier -> identifier = replacement as IdentifierReference
+            node === arrayindexed -> arrayindexed = replacement as ArrayIndexedExpression
             else -> throw FatalAstException("invalid replace")
         }
         replacement.parent = this
@@ -412,17 +418,17 @@ data class AssignTarget(var identifier: IdentifierReference?,
         }
     }
 
-    fun inferType(program: Program, stmt: Statement): InferredTypes.InferredType {
-        if(identifier!=null) {
+    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)
         }
 
-        if(arrayindexed!=null) {
+        if (arrayindexed != null) {
             return arrayindexed!!.inferType(program)
         }
 
-        if(memoryAddress!=null)
+        if (memoryAddress != null)
             return InferredTypes.knownFor(DataType.UBYTE)
 
         return InferredTypes.unknown()
@@ -430,69 +436,93 @@ data class AssignTarget(var identifier: IdentifierReference?,
 
     fun toExpression(): Expression {
         return when {
-            identifier!=null -> identifier!!
-            arrayindexed!=null -> arrayindexed!!
-            memoryAddress!=null -> DirectMemoryRead(memoryAddress.addressExpression, memoryAddress.position)
+            identifier != null -> identifier!!
+            arrayindexed != null -> arrayindexed!!
+            memoryAddress != null -> DirectMemoryRead(memoryAddress.addressExpression, memoryAddress.position)
             else -> throw FatalAstException("invalid assignmenttarget $this")
         }
     }
 
     infix fun isSameAs(value: Expression): Boolean {
         return when {
-            this.memoryAddress!=null -> {
+            memoryAddress != null -> {
                 // if the target is a memory write, and the value is a memory read, they're the same if the address matches
-                if(value is DirectMemoryRead)
+                if (value is DirectMemoryRead)
                     this.memoryAddress.addressExpression isSameAs value.addressExpression
                 else
                     false
             }
-            this.identifier!=null -> value is IdentifierReference && value.nameInSource==identifier!!.nameInSource
-            this.arrayindexed!=null -> value is ArrayIndexedExpression &&
-                    value.identifier.nameInSource==arrayindexed!!.identifier.nameInSource &&
-                    value.arrayspec.constIndex()!=null &&
-                    arrayindexed!!.arrayspec.constIndex()!=null &&
-                    value.arrayspec.constIndex()==arrayindexed!!.arrayspec.constIndex()
+            identifier != null -> value is IdentifierReference && value.nameInSource == identifier!!.nameInSource
+            arrayindexed != null -> {
+                if(value is ArrayIndexedExpression && value.identifier.nameInSource == arrayindexed!!.identifier.nameInSource)
+                    arrayindexed!!.arrayspec isSameAs value.arrayspec
+                else
+                    false
+            }
             else -> false
         }
     }
 
     fun isSameAs(other: AssignTarget, program: Program): Boolean {
-        if(this===other)
+        if (this === other)
             return true
-        if(this.identifier!=null && other.identifier!=null)
-            return this.identifier!!.nameInSource==other.identifier!!.nameInSource
-        if(this.memoryAddress!=null && other.memoryAddress!=null) {
+        if (this.identifier != null && other.identifier != null)
+            return this.identifier!!.nameInSource == other.identifier!!.nameInSource
+        if (this.memoryAddress != null && other.memoryAddress != null) {
             val addr1 = this.memoryAddress.addressExpression.constValue(program)
             val addr2 = other.memoryAddress.addressExpression.constValue(program)
-            return addr1!=null && addr2!=null && addr1==addr2
+            return addr1 != null && addr2 != null && addr1 == addr2
         }
-        if(this.arrayindexed!=null && other.arrayindexed!=null) {
-            if(this.arrayindexed!!.identifier.nameInSource == other.arrayindexed!!.identifier.nameInSource) {
+        if (this.arrayindexed != null && other.arrayindexed != null) {
+            if (this.arrayindexed!!.identifier.nameInSource == other.arrayindexed!!.identifier.nameInSource) {
                 val x1 = this.arrayindexed!!.arrayspec.index.constValue(program)
                 val x2 = other.arrayindexed!!.arrayspec.index.constValue(program)
-                return x1!=null && x2!=null && x1==x2
+                return x1 != null && x2 != null && x1 == x2
             }
         }
         return false
     }
 
-    fun isNotMemory(namespace: INameScope): Boolean {
-        if(this.memoryAddress!=null)
-            return false
-        if(this.arrayindexed!=null) {
-            val targetStmt = this.arrayindexed!!.identifier.targetVarDecl(namespace)
-            if(targetStmt!=null)
-                return targetStmt.type!= VarDeclType.MEMORY
+    fun isInRegularRAM(namespace: INameScope): Boolean {
+        when {
+            this.memoryAddress != null -> {
+                return when (this.memoryAddress.addressExpression) {
+                    is NumericLiteralValue -> {
+                        CompilationTarget.instance.machine.isRegularRAMaddress((this.memoryAddress.addressExpression as NumericLiteralValue).number.toInt())
+                    }
+                    is IdentifierReference -> {
+                        val decl = (this.memoryAddress.addressExpression as IdentifierReference).targetVarDecl(namespace)
+                        if ((decl?.type == VarDeclType.VAR || decl?.type == VarDeclType.CONST) && decl.value is NumericLiteralValue)
+                            CompilationTarget.instance.machine.isRegularRAMaddress((decl.value as NumericLiteralValue).number.toInt())
+                        else
+                            false
+                    }
+                    else -> false
+                }
+            }
+            this.arrayindexed != null -> {
+                val targetStmt = this.arrayindexed!!.identifier.targetVarDecl(namespace)
+                return if (targetStmt?.type == VarDeclType.MEMORY) {
+                    val addr = targetStmt.value as? NumericLiteralValue
+                    if (addr != null)
+                        CompilationTarget.instance.machine.isRegularRAMaddress(addr.number.toInt())
+                    else
+                        false
+                } else true
+            }
+            this.identifier != null -> {
+                val decl = this.identifier!!.targetVarDecl(namespace)!!
+                return if (decl.type == VarDeclType.MEMORY && decl.value is NumericLiteralValue)
+                    CompilationTarget.instance.machine.isRegularRAMaddress((decl.value as NumericLiteralValue).number.toInt())
+                else
+                    true
+            }
+            else -> return true
         }
-        if(this.identifier!=null) {
-            val targetStmt = this.identifier!!.targetVarDecl(namespace)
-            if(targetStmt!=null)
-                return targetStmt.type!= VarDeclType.MEMORY
-        }
-        return false
     }
 }
 
+
 class PostIncrDecr(var target: AssignTarget, val operator: String, override val position: Position) : Statement() {
     override lateinit var parent: Node
 
@@ -581,6 +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
@@ -634,6 +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) {
@@ -815,19 +847,19 @@ class RepeatLoop(var iterations: Expression?, var body: AnonymousScope, override
 }
 
 class UntilLoop(var body: AnonymousScope,
-                var untilCondition: Expression,
+                var condition: Expression,
                 override val position: Position) : Statement() {
     override lateinit var parent: Node
 
     override fun linkParents(parent: Node) {
         this.parent = parent
-        untilCondition.linkParents(this)
+        condition.linkParents(this)
         body.linkParents(this)
     }
 
     override fun replaceChildNode(node: Node, replacement: Node) {
         when {
-            node===untilCondition -> untilCondition = replacement as Expression
+            node===condition -> condition = replacement as Expression
             node===body -> body = replacement as AnonymousScope
             else -> throw FatalAstException("invalid replace")
         }
@@ -911,6 +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

@@ -17,8 +17,13 @@ internal class BeforeAsmGenerationAstChanger(val program: Program, val errors: E
     override fun after(decl: VarDecl, parent: Node): Iterable<IAstModification> {
         subroutineVariables.add(Pair(decl.name, decl))
         if (decl.value == null && !decl.autogeneratedDontRemove && decl.type == VarDeclType.VAR && decl.datatype in NumericDatatypes) {
-            // a numeric vardecl without an initial value is initialized with zero.
-            decl.value = decl.zeroElementValue()
+            // a numeric vardecl without an initial value is initialized with zero,
+            // unless there's already an assignment below, that initializes the value
+            val nextAssign = decl.definingScope().nextSibling(decl) as? Assignment
+            if(nextAssign!=null && nextAssign.target.isSameAs(IdentifierReference(listOf(decl.name), Position.DUMMY)))
+                decl.value = null
+            else
+                decl.value = decl.zeroElementValue()
         }
         return noModifications
     }
@@ -26,16 +31,31 @@ internal class BeforeAsmGenerationAstChanger(val program: Program, val errors: E
     override fun after(assignment: Assignment, parent: Node): Iterable<IAstModification> {
         // Try to replace A = B <operator> Something  by A= B, A = A <operator> Something
         // this triggers the more efficent augmented assignment code generation more often.
+        // But it can only be done if the target variable IS NOT OCCURRING AS AN OPERAND ITSELF.
         if(!assignment.isAugmentable
                 && assignment.target.identifier != null
-                && assignment.target.isNotMemory(program.namespace)) {
+                && assignment.target.isInRegularRAM(program.namespace)) {
             val binExpr = assignment.value as? BinaryExpression
-            if(binExpr!=null && binExpr.operator !in comparisonOperators) {
-                if(binExpr.left !is BinaryExpression) {
-                    val assignLeft = Assignment(assignment.target, binExpr.left, assignment.position)
-                    return listOf(
-                            IAstModification.InsertBefore(assignment, assignLeft, parent),
-                            IAstModification.ReplaceNode(binExpr.left, assignment.target.toExpression(), binExpr))
+            if (binExpr != null && binExpr.operator !in comparisonOperators) {
+                if (binExpr.left !is BinaryExpression) {
+                    if (binExpr.right.referencesIdentifier(*assignment.target.identifier!!.nameInSource.toTypedArray())) {
+                        // the right part of the expression contains the target variable itself.
+                        // we can't 'split' it trivially because the variable will be changed halfway through.
+                        if(binExpr.operator in associativeOperators) {
+                            // A = <something-without-A>  <associativeoperator>  <otherthing-with-A>
+                            // use the other part of the expression to split.
+                            val assignRight = Assignment(assignment.target, binExpr.right, assignment.position)
+                            return listOf(
+                                    IAstModification.InsertBefore(assignment, assignRight, parent),
+                                    IAstModification.ReplaceNode(binExpr.right, binExpr.left, binExpr),
+                                    IAstModification.ReplaceNode(binExpr.left, assignment.target.toExpression(), binExpr))
+                        }
+                    } else {
+                        val assignLeft = Assignment(assignment.target, binExpr.left, assignment.position)
+                        return listOf(
+                                IAstModification.InsertBefore(assignment, assignLeft, parent),
+                                IAstModification.ReplaceNode(binExpr.left, assignment.target.toExpression(), binExpr))
+                    }
                 }
             }
         }
@@ -106,7 +126,6 @@ internal class BeforeAsmGenerationAstChanger(val program: Program, val errors: E
                 && outerScope !is Block) {
             mods += IAstModification.InsertAfter(outerStatements[subroutineStmtIdx - 1], returnStmt, outerScope as Node)
         }
-
         return mods
     }
 
@@ -142,11 +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)
             }
@@ -154,4 +175,34 @@ internal class BeforeAsmGenerationAstChanger(val program: Program, val errors: E
 
         return noModifications
     }
+
+    override fun after(ifStatement: IfStatement, parent: Node): Iterable<IAstModification> {
+        val binExpr = ifStatement.condition as? BinaryExpression
+        if(binExpr==null || binExpr.operator !in comparisonOperators) {
+            // if x  ->  if x!=0,    if x+5  ->  if x+5 != 0
+            val booleanExpr = BinaryExpression(ifStatement.condition, "!=", NumericLiteralValue.optimalInteger(0, ifStatement.condition.position), ifStatement.condition.position)
+            return listOf(IAstModification.ReplaceNode(ifStatement.condition, booleanExpr, ifStatement))
+        }
+        return noModifications
+    }
+
+    override fun after(untilLoop: UntilLoop, parent: Node): Iterable<IAstModification> {
+        val binExpr = untilLoop.condition as? BinaryExpression
+        if(binExpr==null || binExpr.operator !in comparisonOperators) {
+            // until x  ->  until x!=0,    until x+5  ->  until x+5 != 0
+            val booleanExpr = BinaryExpression(untilLoop.condition, "!=", NumericLiteralValue.optimalInteger(0, untilLoop.condition.position), untilLoop.condition.position)
+            return listOf(IAstModification.ReplaceNode(untilLoop.condition, booleanExpr, untilLoop))
+        }
+        return noModifications
+    }
+
+    override fun after(whileLoop: WhileLoop, parent: Node): Iterable<IAstModification> {
+        val binExpr = whileLoop.condition as? BinaryExpression
+        if(binExpr==null || binExpr.operator !in comparisonOperators) {
+            // while x  ->  while x!=0,    while x+5  ->  while x+5 != 0
+            val booleanExpr = BinaryExpression(whileLoop.condition, "!=", NumericLiteralValue.optimalInteger(0, whileLoop.condition.position), whileLoop.condition.position)
+            return listOf(IAstModification.ReplaceNode(whileLoop.condition, booleanExpr, whileLoop))
+        }
+        return noModifications
+    }
 }

compiler/src/prog8/compiler/Compiler.kt

@@ -27,7 +27,8 @@ data class CompilationOptions(val output: OutputType,
                               val launcher: LauncherType,
                               val zeropage: ZeropageType,
                               val zpReserved: List<IntRange>,
-                              val floats: Boolean)
+                              val floats: Boolean,
+                              val noSysInit: Boolean)
 
 
 class CompilerException(message: String?) : Exception(message)

compiler/src/prog8/compiler/Main.kt

@@ -7,6 +7,7 @@ import prog8.ast.statements.Directive
 import prog8.compiler.target.C64Target
 import prog8.compiler.target.CompilationTarget
 import prog8.compiler.target.Cx16Target
+import prog8.optimizer.*
 import prog8.optimizer.UnusedCodeRemover
 import prog8.optimizer.constantFold
 import prog8.optimizer.optimizeStatements
@@ -106,9 +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)
 }
@@ -119,12 +120,11 @@ 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()
     val floatsEnabled = allOptions.any { it.name == "enable_floats" }
+    val noSysInit = allOptions.any { it.name == "no_sysinit" }
     var zpType: ZeropageType =
             if (zpoption == null)
                 if(floatsEnabled) ZeropageType.FLOATSAFE else ZeropageType.KERNALSAFE
@@ -160,7 +160,7 @@ private fun determineCompilationOptions(program: Program): CompilationOptions {
     return CompilationOptions(
             if (outputType == null) OutputType.PRG else OutputType.valueOf(outputType),
             if (launcherType == null) LauncherType.BASIC else LauncherType.valueOf(launcherType),
-            zpType, zpReserved, floatsEnabled
+            zpType, zpReserved, floatsEnabled, noSysInit
     )
 }
 
@@ -171,7 +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()
@@ -187,14 +188,15 @@ 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)
-        programAst.constantFold(errors) // because simplified statements and expressions could give rise to more constants that can be folded away
+        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
     }
 
-    val remover = UnusedCodeRemover(errors)
+    val remover = UnusedCodeRemover(programAst, errors)
     remover.visit(programAst)
     remover.applyModifications()
     errors.handle()
@@ -209,6 +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/Zeropage.kt

@@ -70,12 +70,4 @@ abstract class Zeropage(protected val options: CompilationOptions) {
 
     private fun loneByte(address: Int) = address in free && address-1 !in free && address+1 !in free
     private fun sequentialFree(address: Int, size: Int) = free.containsAll((address until address+size).toList())
-
-    enum class ExitProgramStrategy {
-        CLEAN_EXIT,
-        SYSTEM_RESET
-    }
-
-    abstract val exitProgramStrategy: ExitProgramStrategy
-
 }

compiler/src/prog8/compiler/target/CompilationTarget.kt

@@ -17,8 +17,6 @@ internal interface CompilationTarget {
     fun encodeString(str: String, altEncoding: Boolean): List<Short>
     fun decodeString(bytes: List<Short>, altEncoding: Boolean): String
     fun asmGenerator(program: Program, errors: ErrorReporter, zp: Zeropage, options: CompilationOptions, path: Path): IAssemblyGenerator
-    val initProcName: String?
-    val resetProcName: String?
 
     companion object {
         lateinit var instance: CompilationTarget
@@ -35,8 +33,6 @@ internal object C64Target: CompilationTarget {
             if(altEncoding) Petscii.decodeScreencode(bytes, true) else Petscii.decodePetscii(bytes, true)
     override fun asmGenerator(program: Program, errors: ErrorReporter, zp: Zeropage, options: CompilationOptions, path: Path) =
             AsmGen(program, errors, zp, options, path)
-    override val initProcName = "c64.init_system"
-    override val resetProcName = "c64.reset_system"
 }
 
 internal object Cx16Target: CompilationTarget {
@@ -48,6 +44,4 @@ internal object Cx16Target: CompilationTarget {
             if(altEncoding) Petscii.decodeScreencode(bytes, true) else Petscii.decodePetscii(bytes, true)
     override fun asmGenerator(program: Program, errors: ErrorReporter, zp: Zeropage, options: CompilationOptions, path: Path) =
             AsmGen(program, errors, zp, options, path)
-    override val initProcName = "cx16.init_system"
-    override val resetProcName = "cx16.reset_system"
 }

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

@@ -35,4 +35,5 @@ internal interface IMachineDefinition {
     fun getFloatRomConst(number: Double): String?
     fun importLibs(compilerOptions: CompilationOptions, importer: ModuleImporter, program: Program)
     fun launchEmulator(programName: String)
+    fun isRegularRAMaddress(address: Int): Boolean
 }

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

@@ -37,7 +37,8 @@ internal object C64MachineDefinition: IMachineDefinition {
         val mflpt5 = Mflpt5.fromNumber(number)
         val floatbytes = shortArrayOf(mflpt5.b0, mflpt5.b1, mflpt5.b2, mflpt5.b3, mflpt5.b4)
         when {
-            floatbytes.contentEquals(shortArrayOf(0x00, 0x00, 0x00, 0x00, 0x00)) -> return "floats.ZERO"        // not a ROM const
+            floatbytes.contentEquals(shortArrayOf(0x00, 0x00, 0x00, 0x00, 0x00)) -> return "floats.FL_ZERO_const"        // not a ROM const
+            floatbytes.contentEquals(shortArrayOf(0x81, 0x00, 0x00, 0x00, 0x00)) -> return "floats.FL_ONE_const"        // not a ROM const
             floatbytes.contentEquals(shortArrayOf(0x82, 0x49, 0x0f, 0xda, 0xa1)) -> return "floats.FL_PIVAL"
             floatbytes.contentEquals(shortArrayOf(0x90, 0x80, 0x00, 0x00, 0x00)) -> return "floats.FL_N32768"
             floatbytes.contentEquals(shortArrayOf(0x81, 0x00, 0x00, 0x00, 0x00)) -> return "floats.FL_FONE"
@@ -88,6 +89,8 @@ internal object C64MachineDefinition: IMachineDefinition {
         }
     }
 
+    override fun isRegularRAMaddress(address: Int): Boolean = address<0xa000 || address in 0xc000..0xcfff
+
     override fun initializeZeropage(compilerOptions: CompilationOptions) {
         zeropage = C64Zeropage(compilerOptions)
     }
@@ -112,12 +115,6 @@ internal object C64MachineDefinition: IMachineDefinition {
         override val SCRATCH_W2 = 0xfd      // temp storage 2 for a word  $fb+$fc
 
 
-        override val exitProgramStrategy: ExitProgramStrategy = when (options.zeropage) {
-            ZeropageType.BASICSAFE, ZeropageType.DONTUSE -> ExitProgramStrategy.CLEAN_EXIT
-            ZeropageType.FLOATSAFE, ZeropageType.KERNALSAFE, ZeropageType.FULL -> ExitProgramStrategy.SYSTEM_RESET
-        }
-
-
         init {
             if (options.floats && options.zeropage !in setOf(ZeropageType.FLOATSAFE, ZeropageType.BASICSAFE, ZeropageType.DONTUSE ))
                 throw CompilerException("when floats are enabled, zero page type should be 'floatsafe' or 'basicsafe' or 'dontuse'")

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

@@ -47,10 +47,10 @@ internal class AsmGen(private val program: Program,
     private val forloopsAsmGen = ForLoopsAsmGen(program, this)
     private val postincrdecrAsmGen = PostIncrDecrAsmGen(program, this)
     private val functioncallAsmGen = FunctionCallAsmGen(program, this)
-    private val assignmentAsmGen = AssignmentAsmGen(program, this)
     private val expressionsAsmGen = ExpressionsAsmGen(program, this)
+    private val assignmentAsmGen = AssignmentAsmGen(program, this, expressionsAsmGen)
     internal val loopEndLabels = ArrayDeque<String>()
-    internal val blockLevelVarInits = mutableMapOf<Block, MutableSet<VarDecl>>()
+    private val blockLevelVarInits = mutableMapOf<Block, MutableSet<VarDecl>>()
 
     override fun compileToAssembly(optimize: Boolean): IAssemblyProgram {
         assemblyLines.clear()
@@ -81,6 +81,7 @@ internal class AsmGen(private val program: Program,
         return AssemblyProgram(program.name, outputDir)
     }
 
+
     private fun header() {
         val ourName = this.javaClass.name
         val cpu = when(CompilationTarget.instance.machine.cpu) {
@@ -120,18 +121,14 @@ internal class AsmGen(private val program: Program,
                 out("  .null  $9e, format(' %d ', _prog8_entrypoint), $3a, $8f, ' prog8 by idj'")
                 out("+\t.word  0")
                 out("_prog8_entrypoint\t; assembly code starts here\n")
-                out("  tsx")
-                out("  stx  prog8_lib.orig_stackpointer")
-                if(!CompilationTarget.instance.initProcName.isNullOrEmpty())
-                    out("  jsr  ${CompilationTarget.instance.initProcName}")
+                if(!options.noSysInit)
+                    out("  jsr  ${CompilationTarget.instance.name}.init_system")
             }
             options.output == OutputType.PRG -> {
                 out("; ---- program without basic sys call ----")
                 out("* = ${program.actualLoadAddress.toHex()}\n")
-                out("  tsx")
-                out("  stx  prog8_lib.orig_stackpointer")
-                if(!CompilationTarget.instance.initProcName.isNullOrEmpty())
-                    out("  jsr  ${CompilationTarget.instance.initProcName}")
+                if(!options.noSysInit)
+                    out("  jsr  ${CompilationTarget.instance.name}.init_system")
             }
             options.output == OutputType.RAW -> {
                 out("; ---- raw assembler program ----")
@@ -139,33 +136,16 @@ internal class AsmGen(private val program: Program,
             }
         }
 
-        if (zeropage.exitProgramStrategy != Zeropage.ExitProgramStrategy.CLEAN_EXIT) {
-            // disable shift-commodore charset switching and run/stop key
-            out("  lda  #$80")
-            out("  lda  #$80")
-            out("  sta  657\t; disable charset switching")
-            out("  lda  #239")
-            out("  sta  808\t; disable run/stop key")
+        if(options.zeropage !in setOf(ZeropageType.BASICSAFE, ZeropageType.DONTUSE)) {
+            out("""
+                ; zeropage is clobbered so we need to reset the machine at exit
+                lda  #>${CompilationTarget.instance.name}.reset_system
+                pha
+                lda  #<${CompilationTarget.instance.name}.reset_system
+                pha""")
         }
 
-        out("  ldx  #\$ff\t; init estack pointer")
-
-        out("  ; initialize the variables in each block that has globals")
-        program.allBlocks().forEach {
-            if(it.statements.filterIsInstance<VarDecl>().any { vd->vd.value!=null && vd.type==VarDeclType.VAR && vd.datatype in NumericDatatypes})
-                out("  jsr  ${it.name}.prog8_init_vars")
-        }
-
-        out("  clc")
-        when (zeropage.exitProgramStrategy) {
-            Zeropage.ExitProgramStrategy.CLEAN_EXIT -> {
-                out("  jmp  main.start\t; jump to program entrypoint")
-            }
-            Zeropage.ExitProgramStrategy.SYSTEM_RESET -> {
-                out("  jsr  main.start\t; call program entrypoint")
-                out("  jmp  ${CompilationTarget.instance.resetProcName}")
-            }
-        }
+        out("  jmp  main.start  ; start program / force start proc to be included")
     }
 
     private fun footer() {
@@ -214,11 +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)
     }
@@ -426,10 +405,17 @@ internal class AsmGen(private val program: Program,
                     "$"+number.toString(16).padStart(2, '0')
                 }
             DataType.ARRAY_UW -> array.map {
-                if(it is NumericLiteralValue) {
-                    "$" + it.number.toInt().toString(16).padStart(4, '0')
-                } else {
-                    (it as AddressOf).identifier.nameInSource.joinToString(".")
+                when (it) {
+                    is NumericLiteralValue -> {
+                        "$" + it.number.toInt().toString(16).padStart(4, '0')
+                    }
+                    is AddressOf -> {
+                        it.identifier.firstStructVarName(program.namespace) ?: asmSymbolName(it.identifier)
+                    }
+                    is IdentifierReference -> {
+                        it.firstStructVarName(program.namespace) ?: asmSymbolName(it)
+                    }
+                    else -> throw AssemblyError("weird array elt dt")
                 }
             }
             else -> throw AssemblyError("invalid arraysize type")
@@ -509,8 +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)
@@ -551,55 +543,71 @@ 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 {
-                    val save = makeLabel("saveX")
-                    saveRegisterLabels.push(save)
-                    out("""
-            stx  $save
-            jmp  +
-$save       .byte 0
-+""")
+    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 {
-                    val save = makeLabel("saveY")
-                    out("""
-            sty  $save
-            jmp  +
-$save       .byte 0
-+""")
+
+        } 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 {
-                    val save = saveRegisterLabels.pop()
-                    out("  ldx  $save")
-                }
+    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 {
-                    val save = saveRegisterLabels.pop()
-                    out("  ldy  $save")
+
+        } 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")
                 }
             }
         }
@@ -619,19 +627,22 @@ $save       .byte 0
             is FunctionCallStatement -> {
                 val functionName = stmt.target.nameInSource.last()
                 val builtinFunc = BuiltinFunctions[functionName]
-                if(builtinFunc!=null) {
+                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) {
+                    for ((t, reg) in returns) {
+                        if (reg.stack) {
                             if (t in IntegerDatatypes || t in PassByReferenceDatatypes) out("  inx")
                             else if (t == DataType.FLOAT) out("  inx |  inx |  inx")
                         }
                     }
+                    if(preserveStatusRegisterAfterCall)
+                        out("  plp\t; restore status flags from call")
                 }
             }
             is Assignment -> assignmentAsmGen.translate(stmt)
@@ -752,10 +763,41 @@ $save       .byte 0
             }
             else {
                 expressionsAsmGen.translateExpression(index)
-                when(register) {
-                    CpuRegister.A -> out("  inx |  lda  P8ESTACK_LO,x")
-                    CpuRegister.X -> out("  inx |  lda  P8ESTACK_LO,x |  tax")
-                    CpuRegister.Y -> out("  inx |  ldy  P8ESTACK_LO,x")
+                when(elementDt) {
+                    in ByteDatatypes -> {
+                        when (register) {
+                            CpuRegister.A -> out("  inx |  lda  P8ESTACK_LO,x")
+                            CpuRegister.X -> out("  inx |  lda  P8ESTACK_LO,x |  tax")
+                            CpuRegister.Y -> out("  inx |  ldy  P8ESTACK_LO,x")
+                        }
+                    }
+                    in WordDatatypes -> {
+                        out("""
+                            inx
+                            lda  P8ESTACK_LO,x
+                            asl  a""")
+                        when (register) {
+                            CpuRegister.A -> {}
+                            CpuRegister.X -> out("  tax")
+                            CpuRegister.Y -> out("  tay")
+                        }
+                    }
+                    DataType.FLOAT -> {
+                        require(DataType.FLOAT.memorySize()==5)
+                        out("""
+                            inx
+                            lda  P8ESTACK_LO,x
+                            asl  a
+                            asl  a
+                            clc
+                            adc  P8ESTACK_LO,x""")
+                        when (register) {
+                            CpuRegister.A -> {}
+                            CpuRegister.X -> out("  tax")
+                            CpuRegister.Y -> out("  tay")
+                        }
+                    }
+                    else -> throw AssemblyError("weird dt")
                 }
             }
         }
@@ -767,8 +809,8 @@ $save       .byte 0
     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)
@@ -790,9 +832,33 @@ $save       .byte 0
             out("${sub.name}\t.proc")
             zeropagevars2asm(sub.statements)
             memdefs2asm(sub.statements)
+
+            // the main.start subroutine is the program's entrypoint and should perform some initialization logic
+            if(sub.name=="start" && sub.definingBlock().name=="main") {
+                out("; program startup initialization")
+                out("  cld")
+                program.allBlocks().forEach {
+                    if(it.statements.filterIsInstance<VarDecl>().any { vd->vd.value!=null && vd.type==VarDeclType.VAR && vd.datatype in NumericDatatypes})
+                        out("  jsr  ${it.name}.prog8_init_vars")
+                }
+                out("""
+                    tsx
+                    stx  prog8_lib.orig_stackpointer    ; required for func_exit                    
+                    ldx  #255       ; init estack ptr
+                    clv
+                    clc""")
+            }
+
             out("; statements")
             sub.statements.forEach{ translate(it) }
             out("; variables")
+            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")
         }
@@ -824,47 +890,32 @@ $save       .byte 0
             }
 
     private fun translate(stmt: IfStatement) {
-        when {
-            stmt.elsepart.containsNoCodeNorVars() -> {
-                // empty else
-                expressionsAsmGen.translateExpression(stmt.condition)
-                translateTestStack(stmt.condition.inferType(program).typeOrElse(DataType.STRUCT))
-                val endLabel = makeLabel("if_end")
-                out("  beq  $endLabel")
-                translate(stmt.truepart)
-                out(endLabel)
-            }
-            stmt.truepart.containsNoCodeNorVars() -> {
-                // empty true part
-                expressionsAsmGen.translateExpression(stmt.condition)
-                translateTestStack(stmt.condition.inferType(program).typeOrElse(DataType.STRUCT))
-                val endLabel = makeLabel("if_end")
-                out("  bne  $endLabel")
-                translate(stmt.elsepart)
-                out(endLabel)
-            }
-            else -> {
-                expressionsAsmGen.translateExpression(stmt.condition)
-                translateTestStack(stmt.condition.inferType(program).typeOrElse(DataType.STRUCT))
-                val elseLabel = makeLabel("if_else")
-                val endLabel = makeLabel("if_end")
-                out("  beq  $elseLabel")
-                translate(stmt.truepart)
-                out("  jmp  $endLabel")
-                out(elseLabel)
-                translate(stmt.elsepart)
-                out(endLabel)
-            }
+        checkBooleanExpression(stmt.condition)  // we require the condition to be of the form  'x <comparison> <value>'
+        val booleanCondition = stmt.condition as BinaryExpression
+
+        if (stmt.elsepart.containsNoCodeNorVars()) {
+            // empty else
+            val endLabel = makeLabel("if_end")
+            expressionsAsmGen.translateComparisonExpressionWithJumpIfFalse(booleanCondition, endLabel)
+            translate(stmt.truepart)
+            out(endLabel)
+        }
+        else {
+            // both true and else parts
+            val elseLabel = makeLabel("if_else")
+            val endLabel = makeLabel("if_end")
+            expressionsAsmGen.translateComparisonExpressionWithJumpIfFalse(booleanCondition, elseLabel)
+            translate(stmt.truepart)
+            out("  jmp  $endLabel")
+            out(elseLabel)
+            translate(stmt.elsepart)
+            out(endLabel)
         }
     }
 
-    private fun translateTestStack(dataType: DataType) {
-        when(dataType) {
-            in ByteDatatypes -> out("  inx |  lda  P8ESTACK_LO,x")
-            in WordDatatypes -> out("  inx |  lda  P8ESTACK_LO,x |  ora  P8ESTACK_HI,x")
-            DataType.FLOAT -> throw AssemblyError("conditional value should be an integer (boolean)")
-            else -> throw AssemblyError("non-numerical dt")
-        }
+    private fun checkBooleanExpression(condition: Expression) {
+        if(condition !is BinaryExpression || condition.operator !in comparisonOperators)
+            throw AssemblyError("expected boolean expression $condition")
     }
 
     private fun translate(stmt: RepeatLoop) {
@@ -935,7 +986,11 @@ $save       .byte 0
         // 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  +
@@ -964,6 +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)
@@ -983,25 +1039,13 @@ $counterVar    .byte  0""")
     }
 
     private fun translate(stmt: WhileLoop) {
+        checkBooleanExpression(stmt.condition)  // we require the condition to be of the form  'x <comparison> <value>'
+        val booleanCondition = stmt.condition as BinaryExpression
         val whileLabel = makeLabel("while")
         val endLabel = makeLabel("whileend")
         loopEndLabels.push(endLabel)
         out(whileLabel)
-        expressionsAsmGen.translateExpression(stmt.condition)
-        val conditionDt = stmt.condition.inferType(program)
-        if(!conditionDt.isKnown)
-            throw AssemblyError("unknown condition dt")
-        if(conditionDt.typeOrElse(DataType.BYTE) in ByteDatatypes) {
-            out("  inx |  lda  P8ESTACK_LO,x  |  beq  $endLabel")
-        } else {
-            out("""
-                inx
-                lda  P8ESTACK_LO,x
-                bne  +
-                lda  P8ESTACK_HI,x
-                beq  $endLabel
-+  """)
-        }
+        expressionsAsmGen.translateComparisonExpressionWithJumpIfFalse(booleanCondition, endLabel)
         translate(stmt.body)
         out("  jmp  $whileLabel")
         out(endLabel)
@@ -1009,26 +1053,14 @@ $counterVar    .byte  0""")
     }
 
     private fun translate(stmt: UntilLoop) {
+        checkBooleanExpression(stmt.condition)  // we require the condition to be of the form  'x <comparison> <value>'
+        val booleanCondition = stmt.condition as BinaryExpression
         val repeatLabel = makeLabel("repeat")
         val endLabel = makeLabel("repeatend")
         loopEndLabels.push(endLabel)
         out(repeatLabel)
         translate(stmt.body)
-        expressionsAsmGen.translateExpression(stmt.untilCondition)
-        val conditionDt = stmt.untilCondition.inferType(program)
-        if(!conditionDt.isKnown)
-            throw AssemblyError("unknown condition dt")
-        if(conditionDt.typeOrElse(DataType.BYTE) in ByteDatatypes) {
-            out("  inx |  lda  P8ESTACK_LO,x  |  beq  $repeatLabel")
-        } else {
-            out("""
-                inx
-                lda  P8ESTACK_LO,x
-                bne  +
-                lda  P8ESTACK_HI,x
-                beq  $repeatLabel
-+ """)
-        }
+        expressionsAsmGen.translateComparisonExpressionWithJumpIfFalse(booleanCondition, repeatLabel)
         out(endLabel)
         loopEndLabels.pop()
     }
@@ -1068,6 +1100,7 @@ $counterVar    .byte  0""")
                 }
             }
         }
+        out("  jmp  $endLabel")
         for(choiceBlock in choiceBlocks) {
             out(choiceBlock.first)
             translate(choiceBlock.second)
@@ -1190,4 +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/AsmOptimizer.kt

@@ -179,6 +179,7 @@ private fun optimizeSameAssignments(linesByFourteen: List<List<IndexedValue<Stri
 }
 
 private fun optimizeStoreLoadSame(linesByFour: List<List<IndexedValue<String>>>): List<Modification> {
+    // TODO not sure if this is correct in all situations....:
     // sta X + lda X,  sty X + ldy X,   stx X + ldx X  -> the second instruction can be eliminated
     val mods = mutableListOf<Modification>()
     for (pair in linesByFour) {

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/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

@@ -8,16 +8,17 @@ import prog8.compiler.AssemblyError
 import prog8.compiler.target.CompilationTarget
 import prog8.compiler.target.CpuType
 import prog8.compiler.target.c64.codegen.AsmGen
+import prog8.compiler.target.c64.codegen.ExpressionsAsmGen
 import prog8.compiler.toHex
 
 
-internal class AssignmentAsmGen(private val program: Program, private val asmgen: AsmGen) {
+internal class AssignmentAsmGen(private val program: Program, private val asmgen: AsmGen, private val exprAsmgen: ExpressionsAsmGen) {
 
-    private val augmentableAsmGen = AugmentableAssignmentAsmGen(program, this, asmgen)
+    private val augmentableAsmGen = AugmentableAssignmentAsmGen(program, this, exprAsmgen, 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
@@ -33,7 +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())
@@ -42,12 +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 ${assign.target.datatype}")
                 }
             }
@@ -115,29 +120,45 @@ internal class AssignmentAsmGen(private val program: Program, private val asmgen
             SourceStorageKind.EXPRESSION -> {
                 val value = assign.source.expression!!
                 when(value) {
-                    is AddressOf -> assignAddressOf(assign.target, value.identifier)
+                    is AddressOf -> {
+                        val sourceName = value.identifier.firstStructVarName(program.namespace) ?: asmgen.asmVariableName(value.identifier)
+                        assignAddressOf(assign.target, sourceName)
+                    }
                     is NumericLiteralValue -> throw AssemblyError("source kind should have been literalnumber")
                     is IdentifierReference -> throw AssemblyError("source kind should have been variable")
                     is ArrayIndexedExpression -> throw AssemblyError("source kind should have been array")
                     is DirectMemoryRead -> throw AssemblyError("source kind should have been memory")
                     is TypecastExpression -> assignTypeCastedValue(assign.target, value.type, value.expression, assign)
-//                    is FunctionCall -> {
-//                        if (assign.target.kind == TargetStorageKind.STACK) {
-//                            asmgen.translateExpression(value)
-//                            assignStackValue(assign.target)
-//                        } else {
-//                            val functionName = value.target.nameInSource.last()
-//                            val builtinFunc = BuiltinFunctions[functionName]
-//                            if (builtinFunc != null) {
-//                                println("!!!!BUILTIN-FUNCCALL target=${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)
                     }
                 }
@@ -155,9 +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
                     }
                 }
@@ -220,6 +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}")
                 }
             }
@@ -318,20 +355,7 @@ internal class AssignmentAsmGen(private val program: Program, private val asmgen
         }
     }
 
-    private fun assignAddressOf(target: AsmAssignTarget, name: IdentifierReference) {
-        val struct = name.memberOfStruct(program.namespace)
-        val sourceName = if (struct != null) {
-            // take the address of the first struct member instead
-            val decl = name.targetVarDecl(program.namespace)!!
-            val firstStructMember = struct.nameOfFirstMember()
-            // find the flattened var that belongs to this first struct member
-            val firstVarName = listOf(decl.name, firstStructMember)
-            val firstVar = name.definingScope().lookup(firstVarName, name) as VarDecl
-            firstVar.name
-        } else {
-            asmgen.fixNameSymbols(name.nameInSource.joinToString("."))
-        }
-
+    private fun assignAddressOf(target: AsmAssignTarget, sourceName: String) {
         when(target.kind) {
             TargetStorageKind.VARIABLE -> {
                 asmgen.out("""
@@ -356,19 +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("""
@@ -471,8 +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("""
@@ -506,8 +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("""
@@ -556,10 +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 -> {
@@ -599,13 +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")
         }
     }
 
@@ -638,9 +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")
@@ -694,6 +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 -> {
@@ -1089,9 +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

@@ -1,17 +1,21 @@
 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
 import prog8.compiler.target.c64.codegen.AsmGen
+import prog8.compiler.target.c64.codegen.ExpressionsAsmGen
 import prog8.compiler.toHex
 import kotlin.math.absoluteValue
 
 internal class AugmentableAssignmentAsmGen(private val program: Program,
                                            private val assignmentAsmGen: AssignmentAsmGen,
+                                           private val exprAsmGen: ExpressionsAsmGen,
                                            private val asmgen: AsmGen) {
     fun translate(assign: AsmAssignment) {
         require(assign.isAugmentable)
@@ -104,6 +108,7 @@ internal class AugmentableAssignmentAsmGen(private val program: Program,
     private fun inplaceModification(target: AsmAssignTarget, operator: String, value: Expression) {
         val valueLv = (value as? NumericLiteralValue)?.number
         val ident = value as? IdentifierReference
+        val memread = value as? DirectMemoryRead
 
         when(target.kind) {
             TargetStorageKind.VARIABLE -> {
@@ -112,7 +117,7 @@ internal class AugmentableAssignmentAsmGen(private val program: Program,
                         when {
                             valueLv != null -> inplaceModification_byte_litval_to_variable(target.asmVarname, target.datatype, operator, valueLv.toInt())
                             ident != null -> inplaceModification_byte_variable_to_variable(target.asmVarname, target.datatype, operator, ident)
-                            // TODO more specialized code for types such as memory read etc.
+                            memread != null -> inplaceModification_byte_memread_to_variable(target.asmVarname, target.datatype, operator, memread)
                             value is TypecastExpression -> {
                                 if (tryRemoveRedundantCast(value, target, operator)) return
                                 inplaceModification_byte_value_to_variable(target.asmVarname, target.datatype, operator, value)
@@ -124,18 +129,7 @@ internal class AugmentableAssignmentAsmGen(private val program: Program,
                         when {
                             valueLv != null -> inplaceModification_word_litval_to_variable(target.asmVarname, target.datatype, operator, valueLv.toInt())
                             ident != null -> inplaceModification_word_variable_to_variable(target.asmVarname, target.datatype, operator, ident)
-                            // TODO more specialized code for types such as memory read etc.
-//                            value is DirectMemoryRead -> {
-//                                println("warning: slow stack evaluation used (8):  $name $operator= ${value::class.simpleName} at ${value.position}")
-//                                // assignmentAsmGen.translateOtherAssignment(origAssign)
-//                                asmgen.translateExpression(value.addressExpression)
-//                                asmgen.out("""
-//                                    jsr  prog8_lib.read_byte_from_address_on_stack
-//                                    sta  ...
-//                                    inx
-//                                    """)
-//                                inplaceModification_word_value_to_variable(name, operator, )
-//                            }
+                            memread != null -> inplaceModification_word_memread_to_variable(target.asmVarname, target.datatype, operator, memread)
                             value is TypecastExpression -> {
                                 if (tryRemoveRedundantCast(value, target, operator)) return
                                 inplaceModification_word_value_to_variable(target.asmVarname, target.datatype, operator, value)
@@ -145,14 +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)
-                            // TODO more specialized code for types such as memory read etc.
+                            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 ${target.datatype}")
@@ -196,7 +189,7 @@ internal class AugmentableAssignmentAsmGen(private val program: Program,
                         when {
                             valueLv != null -> inplaceModification_byte_litval_to_variable(zp.SCRATCH_B1.toHex(), DataType.UBYTE, operator, valueLv.toInt())
                             ident != null -> inplaceModification_byte_variable_to_variable(zp.SCRATCH_B1.toHex(), DataType.UBYTE, operator, ident)
-                            // TODO more specialized code for types such as memory read etc.
+                            memread != null -> inplaceModification_byte_memread_to_variable(zp.SCRATCH_B1.toHex(), DataType.UBYTE, operator, memread)
                             value is TypecastExpression -> {
                                 if (tryRemoveRedundantCast(value, target, operator)) return
                                 inplaceModification_byte_value_to_variable(zp.SCRATCH_B1.toHex(), DataType.UBYTE, operator, value)
@@ -231,123 +224,92 @@ internal class AugmentableAssignmentAsmGen(private val program: Program,
     private fun inplaceModification_byte_value_to_memory(pointervar: IdentifierReference, operator: String, value: Expression) {
         println("warning: slow stack evaluation used (3):  @(${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) {
@@ -370,26 +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) {
@@ -448,19 +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)
@@ -580,33 +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)
@@ -636,20 +588,77 @@ internal class AugmentableAssignmentAsmGen(private val program: Program,
         }
     }
 
+    private fun inplaceModification_byte_memread_to_variable(name: String, dt: DataType, operator: String, memread: DirectMemoryRead) {
+        when(operator) {
+            "+" -> {
+                exprAsmGen.translateDirectMemReadExpression(memread, false)
+                asmgen.out("""
+                    clc
+                    adc  $name
+                    sta  $name""")
+            }
+            "-" -> {
+                exprAsmGen.translateDirectMemReadExpression(memread, false)
+                asmgen.out("""
+                    sta  P8ZP_SCRATCH_B1
+                    lda  $name
+                    sec
+                    sbc  P8ZP_SCRATCH_B1
+                    sta  $name""")
+                // TODO: tuned code for more operators
+            }
+            else -> {
+                inplaceModification_byte_value_to_variable(name, dt, operator, memread);
+            }
+        }
+    }
+
+    private fun inplaceModification_word_memread_to_variable(name: String, dt: DataType, operator: String, memread: DirectMemoryRead) {
+        when(operator) {
+            "+" -> {
+                exprAsmGen.translateDirectMemReadExpression(memread, false)
+                asmgen.out("""
+                    clc
+                    adc  $name
+                    sta  $name
+                    bcc  +
+                    inc  $name+1
++""")
+            }
+            "-" -> {
+                exprAsmGen.translateDirectMemReadExpression(memread, false)
+                asmgen.out("""
+                    sta  P8ZP_SCRATCH_B1
+                    lda  $name
+                    sec
+                    sbc  P8ZP_SCRATCH_B1
+                    sta  $name
+                    bcc  +
+                    dec  $name+1
++""")
+                // TODO: tuned code for more operators
+            }
+            else -> {
+                inplaceModification_word_value_to_variable(name, dt, operator, memread);
+            }
+        }
+    }
+
     private fun inplaceModification_word_litval_to_variable(name: String, dt: DataType, operator: String, value: Int) {
         when (operator) {
             // note: ** (power) operator requires floats.
             // TODO use these + and - optimizations in the expressionAsmGenerator as well.
             "+" -> {
                 when {
-                    value<0x0100 -> asmgen.out("""
+                    value==0 -> {}
+                    value in 1..0xff -> asmgen.out("""
                         lda  $name
                         clc
                         adc  #$value
                         sta  $name
                         bcc  +
                         inc  $name+1
-+                           """)
++""")
                     value==0x0100 -> asmgen.out(" inc  $name+1")
                     value==0x0200 -> asmgen.out(" inc  $name+1 |  inc  $name+1")
                     value==0x0300 -> asmgen.out(" inc  $name+1 |  inc  $name+1 |  inc  $name+1")
@@ -666,14 +675,15 @@ internal class AugmentableAssignmentAsmGen(private val program: Program,
             }
             "-" -> {
                 when {
-                    value<0x0100 -> asmgen.out("""
+                    value==0 -> {}
+                    value in 1..0xff -> asmgen.out("""
                         lda  $name
                         sec
                         sbc  #$value
                         sta  $name
                         bcs  +
                         dec  $name+1
-+                           """)
++""")
                     value==0x0100 -> asmgen.out(" dec  $name+1")
                     value==0x0200 -> asmgen.out(" dec  $name+1 |  dec  $name+1")
                     value==0x0300 -> asmgen.out(" dec  $name+1 |  dec  $name+1 |  dec  $name+1")
@@ -840,22 +850,54 @@ internal class AugmentableAssignmentAsmGen(private val program: Program,
                 // the other variable is a BYTE type so optimize for that
                 when (operator) {
                     // note: ** (power) operator requires floats.
-                    "+" -> asmgen.out("""
-                        lda  $name
-                        clc
-                        adc  $otherName
-                        sta  $name
-                        bcc  +
-                        inc  $name+1
-+                           """)
-                    "-" -> asmgen.out("""
-                        lda  $name
-                        sec
-                        sbc  $otherName
-                        sta  $name
-                        bcs  +
-                        dec  $name+1
-+                           """)
+                    "+" -> {
+                        if(valueDt==DataType.UBYTE)
+                            asmgen.out("""
+                                lda  $name
+                                clc
+                                adc  $otherName
+                                sta  $name
+                                bcc  +
+                                inc  $name+1
++""")
+                        else
+                            asmgen.out("""
+                                ldy  #0
+                                lda  $otherName
+                                bpl  +
+                                dey     ; sign extend
++                               clc
+                                adc  $name
+                                sta  $name
+                                tya
+                                adc  $name+1
+                                sta  $name+1""")
+                    }
+                    "-" -> {
+                        if(valueDt==DataType.UBYTE)
+                            asmgen.out("""
+                                lda  $name
+                                sec
+                                sbc  $otherName
+                                sta  $name
+                                bcs  +
+                                dec  $name+1
++""")
+                        else
+                            asmgen.out("""
+                                ldy  #0
+                                lda  $otherName
+                                bpl  +
+                                dey     ; sign extend
++                               sty  P8ZP_SCRATCH_B1
+                                lda  $name
+                                sec
+                                sbc  $otherName
+                                sta  $name
+                                lda  $name+1
+                                sbc  P8ZP_SCRATCH_B1
+                                sta  $name+1""")
+                    }
                     "*" -> {
                         asmgen.out("""
                             lda  $otherName
@@ -870,8 +912,8 @@ internal class AugmentableAssignmentAsmGen(private val program: Program,
                             lda  math.multiply_words.result+1
                             sta  $name+1""")
                     }
-                    "/" -> TODO("div wordvar/bytevar")
-                    "%" -> TODO("word remainder bytevar")
+                    "/" -> TODO("div (u)wordvar/bytevar")
+                    "%" -> TODO("(u)word remainder bytevar")
                     "<<" -> {
                         asmgen.out("""
                         ldy  $otherName
@@ -899,9 +941,9 @@ internal class AugmentableAssignmentAsmGen(private val program: Program,
                             bne  -""")
                         }
                     }
-                    "&" -> TODO("bitand wordvar bytevar")
-                    "^" -> TODO("bitxor wordvar bytevar")
-                    "|" -> TODO("bitor wordvar bytevar")
+                    "&" -> TODO("bitand (u)wordvar bytevar")
+                    "^" -> TODO("bitxor (u)wordvar bytevar")
+                    "|" -> TODO("bitor (u)wordvar bytevar")
                     else -> throw AssemblyError("invalid operator for in-place modification $operator")
                 }
             }
@@ -991,30 +1033,136 @@ 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   TODO does this even occur?
+                // the other variable is a BYTE type so optimize for that
                 when (operator) {
                     // note: ** (power) operator requires floats.
-                    "+" -> asmgen.out("""
-                        lda  $name
-                        clc
-                        adc  P8ESTACK_LO+1,x
-                        sta  $name
-                        bcc  +
-                        inc  $name+1
-+                           """)
-                    "-" -> asmgen.out("""
-                        lda  $name
-                        sec
-                        sbc  P8ESTACK_LO+1,x
-                        sta  $name
-                        bcs  +
-                        dec  $name+1
-+                           """)
-                    "*" -> TODO("mul word byte")
-                    "/" -> TODO("div word byte")
-                    "%" -> TODO("word remainder byte")
+                    "+" -> {
+                        if(valueDt==DataType.UBYTE)
+                            asmgen.out("""
+                                lda  $name
+                                clc
+                                adc  P8ESTACK_LO+1,x
+                                sta  $name
+                                bcc  +
+                                inc  $name+1
++""")
+                        else
+                            asmgen.out("""
+                                ldy  #0
+                                lda  P8ESTACK_LO+1,x
+                                bpl  +
+                                dey         ; sign extend
++                               clc
+                                adc  $name
+                                sta  $name
+                                tya
+                                adc  $name+1
+                                sta  $name+1""")
+                    }
+                    "-" -> {
+                        if(valueDt==DataType.UBYTE)
+                            asmgen.out("""
+                                lda  $name
+                                sec
+                                sbc  P8ESTACK_LO+1,x
+                                sta  $name
+                                bcc  +
+                                dec  $name+1
++""")
+                        else
+                            asmgen.out("""
+                                ldy  #0
+                                lda  P8ESTACK_LO+1,x
+                                bpl  +
+                                dey         ; sign extend
++                               sty  P8ZP_SCRATCH_B1
+                                lda  $name
+                                sec
+                                sbc  P8ESTACK_LO+1,x
+                                sta  $name
+                                lda  $name+1
+                                sbc  P8ZP_SCRATCH_B1
+                                sta  $name+1""")
+                    }
+                    "*" -> {
+                        // 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("""
@@ -1053,9 +1201,9 @@ internal class AugmentableAssignmentAsmGen(private val program: Program,
 +""")
                         }
                     }
-                    "&" -> TODO("bitand word byte")
-                    "^" -> TODO("bitxor word byte")
-                    "|" -> TODO("bitor word 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")
                 }
             }
@@ -1065,65 +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")
@@ -1139,13 +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 ${value.position}") // TODO
         asmgen.translateExpression(value)
         asmgen.out("  jsr  floats.pop_float_fac1")
-        asmgen.saveRegister(CpuRegister.X)
+        asmgen.saveRegister(CpuRegister.X, false, scope)
         when (operator) {
             "**" -> {
                 asmgen.out("""
@@ -1190,16 +1282,16 @@ internal class AugmentableAssignmentAsmGen(private val program: Program,
             ldy  #>$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("""
@@ -1259,12 +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("""
@@ -1331,7 +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) {
@@ -1567,17 +1659,12 @@ internal class AugmentableAssignmentAsmGen(private val program: Program,
             DataType.FLOAT -> {
                 when(target.kind) {
                     TargetStorageKind.VARIABLE -> {
-                        asmgen.saveRegister(CpuRegister.X)
+                        // simply flip the sign bit in the float
                         asmgen.out("""
-                            lda  #<${target.asmVarname}
-                            ldy  #>${target.asmVarname}
-                            jsr  floats.MOVFM
-                            jsr  floats.NEGOP
-                            ldx  #<${target.asmVarname}
-                            ldy  #>${target.asmVarname}
-                            jsr  floats.MOVMF
+                            lda  ${target.asmVarname}+1
+                            eor  #$80
+                            sta  ${target.asmVarname}+1
                         """)
-                        asmgen.restoreRegister(CpuRegister.X)
                     }
                     TargetStorageKind.ARRAY -> TODO("in-place negate float array")
                     TargetStorageKind.STACK -> TODO("stack float negate")

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

@@ -52,6 +52,8 @@ internal object CX16MachineDefinition: IMachineDefinition {
         }
     }
 
+    override fun isRegularRAMaddress(address: Int): Boolean = address < 0x9f00 || address in 0xa000..0xbfff
+
     override fun initializeZeropage(compilerOptions: CompilationOptions) {
         zeropage = CX16Zeropage(compilerOptions)
     }
@@ -78,13 +80,6 @@ internal object CX16MachineDefinition: IMachineDefinition {
         override val SCRATCH_W2 = 0x7e      // temp storage 2 for a word  $7e+$7f
 
 
-        override val exitProgramStrategy: ExitProgramStrategy = when (options.zeropage) {
-            ZeropageType.BASICSAFE, ZeropageType.DONTUSE -> ExitProgramStrategy.CLEAN_EXIT
-            ZeropageType.KERNALSAFE, ZeropageType.FULL -> ExitProgramStrategy.SYSTEM_RESET
-            else -> ExitProgramStrategy.SYSTEM_RESET
-        }
-
-
         init {
             if (options.floats && options.zeropage !in setOf(ZeropageType.BASICSAFE, ZeropageType.DONTUSE ))
                 throw CompilerException("when floats are enabled, zero page type should be 'basicsafe' or 'dontuse'")

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/ConstantIdentifierReplacer.kt

@@ -58,7 +58,7 @@ internal class ConstantIdentifierReplacer(private val program: Program, private
     override fun before(decl: VarDecl, parent: Node): Iterable<IAstModification> {
         // the initializer value can't refer to the variable itself (recursive definition)
         // TODO: use call graph for this?
-        if(decl.value?.referencesIdentifiers(decl.name) == true || decl.arraysize?.index?.referencesIdentifiers(decl.name) == true) {
+        if(decl.value?.referencesIdentifier(decl.name) == true || decl.arraysize?.index?.referencesIdentifier(decl.name) == true) {
             errors.err("recursive var declaration", decl.position)
             return noModifications
         }

compiler/src/prog8/optimizer/ExpressionSimplifier.kt

@@ -175,28 +175,6 @@ internal class ExpressionSimplifier(private val program: Program) : AstWalker()
                 // unsigned >= 0 --> true
                 return listOf(IAstModification.ReplaceNode(expr, NumericLiteralValue.fromBoolean(true, expr.position), parent))
             }
-            when(leftDt) {
-                DataType.BYTE -> {
-                    // signed >=0   --> signed ^ $80
-                    return listOf(IAstModification.ReplaceNode(
-                            expr,
-                            BinaryExpression(expr.left, "^", NumericLiteralValue.optimalInteger(0x80, expr.position), expr.position),
-                            parent
-                    ))
-                }
-                DataType.WORD -> {
-                    // signedw >=0   --> msb(signedw) ^ $80
-                    return listOf(IAstModification.ReplaceNode(
-                            expr,
-                            BinaryExpression(FunctionCall(IdentifierReference(listOf("msb"), expr.position),
-                                    mutableListOf(expr.left),
-                                    expr.position
-                            ), "^", NumericLiteralValue.optimalInteger(0x80, expr.position), expr.position),
-                            parent
-                    ))
-                }
-                else -> {}
-            }
         }
 
         if(expr.operator == "<" && rightVal?.number == 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()
+}

compiler/src/prog8/optimizer/StatementOptimizer.kt

@@ -49,11 +49,6 @@ internal class StatementOptimizer(private val program: Program,
             }
         }
 
-        val linesToRemove = deduplicateAssignments(subroutine.statements)
-        if(linesToRemove.isNotEmpty()) {
-            linesToRemove.reversed().forEach{subroutine.statements.removeAt(it)}
-        }
-
         if(subroutine !in callgraph.usedSymbols && !forceOutput) {
             errors.warn("removing unused subroutine '${subroutine.name}'", subroutine.position)
             return listOf(IAstModification.Remove(subroutine, parent))
@@ -62,11 +57,6 @@ internal class StatementOptimizer(private val program: Program,
         return noModifications
     }
 
-    override fun after(scope: AnonymousScope, parent: Node): Iterable<IAstModification> {
-        val linesToRemove = deduplicateAssignments(scope.statements)
-        return linesToRemove.reversed().map { IAstModification.Remove(scope.statements[it], scope) }
-    }
-
     override fun after(decl: VarDecl, parent: Node): Iterable<IAstModification> {
         val forceOutput = "force_output" in decl.definingBlock().options()
         if(decl !in callgraph.usedSymbols && !forceOutput) {
@@ -249,11 +239,11 @@ internal class StatementOptimizer(private val program: Program,
     }
 
     override fun before(untilLoop: UntilLoop, parent: Node): Iterable<IAstModification> {
-        val constvalue = untilLoop.untilCondition.constValue(program)
+        val constvalue = untilLoop.condition.constValue(program)
         if(constvalue!=null) {
             if(constvalue.asBooleanValue) {
                 // always true -> keep only the statement block (if there are no break statements)
-                errors.warn("condition is always true", untilLoop.untilCondition.position)
+                errors.warn("condition is always true", untilLoop.condition.position)
                 if(!hasBreak(untilLoop.body))
                     return listOf(IAstModification.ReplaceNode(untilLoop, untilLoop.body, parent))
             } else {
@@ -395,21 +385,21 @@ internal class StatementOptimizer(private val program: Program,
         val targetDt = targetIDt.typeOrElse(DataType.STRUCT)
         val bexpr=assignment.value as? BinaryExpression
         if(bexpr!=null) {
-            val cv = bexpr.right.constValue(program)?.number?.toDouble()
-            if (cv != null && assignment.target isSameAs bexpr.left) {
+            val rightCv = bexpr.right.constValue(program)?.number?.toDouble()
+            if (rightCv != null && assignment.target isSameAs bexpr.left) {
                 // assignments of the form:  X = X <operator> <expr>
                 // remove assignments that have no effect (such as X=X+0)
                 // optimize/rewrite some other expressions
                 val vardeclDt = (assignment.target.identifier?.targetVarDecl(program.namespace))?.type
                 when (bexpr.operator) {
                     "+" -> {
-                        if (cv == 0.0) {
+                        if (rightCv == 0.0) {
                             return listOf(IAstModification.Remove(assignment, parent))
-                        } else if (targetDt in IntegerDatatypes && floor(cv) == cv) {
-                            if (vardeclDt != VarDeclType.MEMORY && cv in 1.0..4.0) {
+                        } else if (targetDt in IntegerDatatypes && floor(rightCv) == rightCv) {
+                            if (vardeclDt != VarDeclType.MEMORY && rightCv in 1.0..4.0) {
                                 // replace by several INCs if it's not a memory address (inc on a memory mapped register doesn't work very well)
                                 val incs = AnonymousScope(mutableListOf(), assignment.position)
-                                repeat(cv.toInt()) {
+                                repeat(rightCv.toInt()) {
                                     incs.statements.add(PostIncrDecr(assignment.target, "++", assignment.position))
                                 }
                                 return listOf(IAstModification.ReplaceNode(assignment, incs, parent))
@@ -417,62 +407,38 @@ internal class StatementOptimizer(private val program: Program,
                         }
                     }
                     "-" -> {
-                        if (cv == 0.0) {
+                        if (rightCv == 0.0) {
                             return listOf(IAstModification.Remove(assignment, parent))
-                        } else if (targetDt in IntegerDatatypes && floor(cv) == cv) {
-                            if (vardeclDt != VarDeclType.MEMORY && cv in 1.0..4.0) {
+                        } else if (targetDt in IntegerDatatypes && floor(rightCv) == rightCv) {
+                            if (vardeclDt != VarDeclType.MEMORY && rightCv in 1.0..4.0) {
                                 // replace by several DECs if it's not a memory address (dec on a memory mapped register doesn't work very well)
                                 val decs = AnonymousScope(mutableListOf(), assignment.position)
-                                repeat(cv.toInt()) {
+                                repeat(rightCv.toInt()) {
                                     decs.statements.add(PostIncrDecr(assignment.target, "--", assignment.position))
                                 }
                                 return listOf(IAstModification.ReplaceNode(assignment, decs, parent))
                             }
                         }
                     }
-                    "*" -> if (cv == 1.0) return listOf(IAstModification.Remove(assignment, parent))
-                    "/" -> if (cv == 1.0) return listOf(IAstModification.Remove(assignment, parent))
-                    "**" -> if (cv == 1.0) return listOf(IAstModification.Remove(assignment, parent))
-                    "|" -> if (cv == 0.0) return listOf(IAstModification.Remove(assignment, parent))
-                    "^" -> if (cv == 0.0) return listOf(IAstModification.Remove(assignment, parent))
+                    "*" -> if (rightCv == 1.0) return listOf(IAstModification.Remove(assignment, parent))
+                    "/" -> if (rightCv == 1.0) return listOf(IAstModification.Remove(assignment, parent))
+                    "**" -> if (rightCv == 1.0) return listOf(IAstModification.Remove(assignment, parent))
+                    "|" -> if (rightCv == 0.0) return listOf(IAstModification.Remove(assignment, parent))
+                    "^" -> if (rightCv == 0.0) return listOf(IAstModification.Remove(assignment, parent))
                     "<<" -> {
-                        if (cv == 0.0)
+                        if (rightCv == 0.0)
                             return listOf(IAstModification.Remove(assignment, parent))
                     }
                     ">>" -> {
-                        if (cv == 0.0)
+                        if (rightCv == 0.0)
                             return listOf(IAstModification.Remove(assignment, parent))
                     }
                 }
 
             }
         }
-        return noModifications
-    }
 
-    private fun deduplicateAssignments(statements: List<Statement>): MutableList<Int> {
-        // removes 'duplicate' assignments that assign the isSameAs target
-        val linesToRemove = mutableListOf<Int>()
-        var previousAssignmentLine: Int? = null
-        for (i in statements.indices) {
-            val stmt = statements[i] as? Assignment
-            if (stmt != null && stmt.value is NumericLiteralValue) {
-                if (previousAssignmentLine == null) {
-                    previousAssignmentLine = i
-                    continue
-                } else {
-                    val prev = statements[previousAssignmentLine] as Assignment
-                    if (prev.target.isSameAs(stmt.target, program)) {
-                        // get rid of the previous assignment, if the target is not MEMORY
-                        if (prev.target.isNotMemory(program.namespace))
-                            linesToRemove.add(previousAssignmentLine)
-                    }
-                    previousAssignmentLine = i
-                }
-            } else
-                previousAssignmentLine = null
-        }
-        return linesToRemove
+        return noModifications
     }
 
     private fun hasBreak(scope: INameScope): Boolean {

compiler/src/prog8/optimizer/UnusedCodeRemover.kt

@@ -8,7 +8,8 @@ import prog8.ast.processing.AstWalker
 import prog8.ast.processing.IAstModification
 import prog8.ast.statements.*
 
-internal class UnusedCodeRemover(private val errors: ErrorReporter): AstWalker() {
+
+internal class UnusedCodeRemover(private val program: Program, private val errors: ErrorReporter): AstWalker() {
 
     override fun before(program: Program, parent: Node): Iterable<IAstModification> {
         val callgraph = CallGraph(program)
@@ -66,4 +67,35 @@ internal class UnusedCodeRemover(private val errors: ErrorReporter): AstWalker()
             else -> errors.warn("unreachable code", next.position)
         }
     }
+
+    override fun after(scope: AnonymousScope, parent: Node): Iterable<IAstModification> {
+        val removeDoubleAssignments = deduplicateAssignments(scope.statements)
+        return removeDoubleAssignments.map { IAstModification.Remove(it, scope) }
+    }
+
+    override fun after(block: Block, parent: Node): Iterable<IAstModification> {
+        val removeDoubleAssignments = deduplicateAssignments(block.statements)
+        return removeDoubleAssignments.map { IAstModification.Remove(it, block) }
+    }
+
+    override fun after(subroutine: Subroutine, parent: Node): Iterable<IAstModification> {
+        val removeDoubleAssignments = deduplicateAssignments(subroutine.statements)
+        return removeDoubleAssignments.map { IAstModification.Remove(it, subroutine) }
+    }
+
+    private fun deduplicateAssignments(statements: List<Statement>): List<Assignment> {
+        // removes 'duplicate' assignments that assign the same target directly after another
+        val linesToRemove = mutableListOf<Assignment>()
+
+        for (stmtPairs in statements.windowed(2, step = 1)) {
+            val assign1 = stmtPairs[0] as? Assignment
+            val assign2 = stmtPairs[1] as? Assignment
+            if (assign1 != null && assign2 != null && !assign2.isAugmentable) {
+                if (assign1.target.isSameAs(assign2.target, program) && assign1.target.isInRegularRAM(program.namespace))
+                    linesToRemove.add(assign1)
+            }
+        }
+
+        return linesToRemove
+    }
 }

compiler/src/prog8/parser/ModuleParsing.kt

@@ -131,13 +131,14 @@ internal class ModuleImporter {
         if(existing!=null)
             return null
 
-        val resource = tryGetEmbeddedResource("$moduleName.p8")
+        val rsc = tryGetEmbeddedResource("$moduleName.p8")
         val importedModule =
-                if(resource!=null) {
+                if(rsc!=null) {
                     // load the module from the embedded resource
+                    val (resource, resourcePath) = rsc
                     resource.use {
                         println("importing '$moduleName' (library)")
-                        importModule(program, CharStreams.fromStream(it), Paths.get("@embedded@/$moduleName"), true)
+                        importModule(program, CharStreams.fromStream(it), Paths.get("@embedded@/$resourcePath"), true)
                     }
                 } else {
                     val modulePath = discoverImportedModuleFile(moduleName, source, import.position)
@@ -148,11 +149,18 @@ internal class ModuleImporter {
         return importedModule
     }
 
-    private fun tryGetEmbeddedResource(name: String): InputStream? {
+    private fun tryGetEmbeddedResource(name: String): Pair<InputStream, String>? {
         val target = CompilationTarget.instance.name
-        val targetSpecific = object{}.javaClass.getResourceAsStream("/prog8lib/$target/$name")
-        if(targetSpecific!=null)
-            return targetSpecific
-        return object{}.javaClass.getResourceAsStream("/prog8lib/$name")
+        val targetSpecificPath = "/prog8lib/$target/$name"
+        val targetSpecificResource = object{}.javaClass.getResourceAsStream(targetSpecificPath)
+        if(targetSpecificResource!=null)
+            return Pair(targetSpecificResource, targetSpecificPath)
+
+        val generalPath = "/prog8lib/$name"
+        val generalResource = object{}.javaClass.getResourceAsStream(generalPath)
+        if(generalResource!=null)
+            return Pair(generalResource, generalPath)
+
+        return null
     }
 }

compiler/test/UnitTests.kt

@@ -5,18 +5,21 @@ import org.hamcrest.Matchers.closeTo
 import org.hamcrest.Matchers.equalTo
 import org.junit.jupiter.api.Test
 import org.junit.jupiter.api.TestInstance
-import prog8.ast.base.DataType
-import prog8.ast.base.ErrorReporter
-import prog8.ast.base.Position
-import prog8.ast.expressions.NumericLiteralValue
-import prog8.ast.expressions.StringLiteralValue
+import prog8.ast.Module
+import prog8.ast.Program
+import prog8.ast.base.*
+import prog8.ast.expressions.*
+import prog8.ast.statements.*
 import prog8.compiler.*
+import prog8.compiler.target.C64Target
+import prog8.compiler.target.CompilationTarget
 import prog8.compiler.target.c64.C64MachineDefinition.C64Zeropage
 import prog8.compiler.target.c64.C64MachineDefinition.FLOAT_MAX_NEGATIVE
 import prog8.compiler.target.c64.C64MachineDefinition.FLOAT_MAX_POSITIVE
 import prog8.compiler.target.c64.C64MachineDefinition.Mflpt5
 import prog8.compiler.target.c64.Petscii
 import java.io.CharConversionException
+import java.nio.file.Path
 import kotlin.test.*
 
 @TestInstance(TestInstance.Lifecycle.PER_CLASS)
@@ -129,7 +132,7 @@ class TestC64Zeropage {
 
     @Test
     fun testNames() {
-        val zp = C64Zeropage(CompilationOptions(OutputType.RAW, LauncherType.NONE, ZeropageType.BASICSAFE, emptyList(), false))
+        val zp = C64Zeropage(CompilationOptions(OutputType.RAW, LauncherType.NONE, ZeropageType.BASICSAFE, emptyList(), false, false))
 
         zp.allocate("", DataType.UBYTE, null, errors)
         zp.allocate("", DataType.UBYTE, null, errors)
@@ -142,37 +145,37 @@ class TestC64Zeropage {
 
     @Test
     fun testZpFloatEnable() {
-        val zp = C64Zeropage(CompilationOptions(OutputType.RAW, LauncherType.NONE, ZeropageType.FULL, emptyList(), false))
+        val zp = C64Zeropage(CompilationOptions(OutputType.RAW, LauncherType.NONE, ZeropageType.FULL, emptyList(), false, false))
         assertFailsWith<CompilerException> {
             zp.allocate("", DataType.FLOAT, null, errors)
         }
-        val zp2 = C64Zeropage(CompilationOptions(OutputType.RAW, LauncherType.NONE, ZeropageType.DONTUSE, emptyList(), true))
+        val zp2 = C64Zeropage(CompilationOptions(OutputType.RAW, LauncherType.NONE, ZeropageType.DONTUSE, emptyList(), true, false))
         assertFailsWith<CompilerException> {
             zp2.allocate("", DataType.FLOAT, null, errors)
         }
-        val zp3 = C64Zeropage(CompilationOptions(OutputType.RAW, LauncherType.NONE, ZeropageType.FLOATSAFE, emptyList(), true))
+        val zp3 = C64Zeropage(CompilationOptions(OutputType.RAW, LauncherType.NONE, ZeropageType.FLOATSAFE, emptyList(), true, false))
         zp3.allocate("", DataType.FLOAT, null, errors)
     }
 
     @Test
     fun testZpModesWithFloats() {
-        C64Zeropage(CompilationOptions(OutputType.RAW, LauncherType.NONE, ZeropageType.FULL, emptyList(), false))
-        C64Zeropage(CompilationOptions(OutputType.RAW, LauncherType.NONE, ZeropageType.KERNALSAFE, emptyList(), false))
-        C64Zeropage(CompilationOptions(OutputType.RAW, LauncherType.NONE, ZeropageType.BASICSAFE, emptyList(), false))
-        C64Zeropage(CompilationOptions(OutputType.RAW, LauncherType.NONE, ZeropageType.FLOATSAFE, emptyList(), false))
-        C64Zeropage(CompilationOptions(OutputType.RAW, LauncherType.NONE, ZeropageType.BASICSAFE, emptyList(), true))
-        C64Zeropage(CompilationOptions(OutputType.RAW, LauncherType.NONE, ZeropageType.FLOATSAFE, emptyList(), true))
+        C64Zeropage(CompilationOptions(OutputType.RAW, LauncherType.NONE, ZeropageType.FULL, emptyList(), false, false))
+        C64Zeropage(CompilationOptions(OutputType.RAW, LauncherType.NONE, ZeropageType.KERNALSAFE, emptyList(), false, false))
+        C64Zeropage(CompilationOptions(OutputType.RAW, LauncherType.NONE, ZeropageType.BASICSAFE, emptyList(), false, false))
+        C64Zeropage(CompilationOptions(OutputType.RAW, LauncherType.NONE, ZeropageType.FLOATSAFE, emptyList(), false, false))
+        C64Zeropage(CompilationOptions(OutputType.RAW, LauncherType.NONE, ZeropageType.BASICSAFE, emptyList(), true, false))
+        C64Zeropage(CompilationOptions(OutputType.RAW, LauncherType.NONE, ZeropageType.FLOATSAFE, emptyList(), true, false))
         assertFailsWith<CompilerException> {
-            C64Zeropage(CompilationOptions(OutputType.RAW, LauncherType.NONE, ZeropageType.FULL, emptyList(), true))
+            C64Zeropage(CompilationOptions(OutputType.RAW, LauncherType.NONE, ZeropageType.FULL, emptyList(), true, false))
         }
         assertFailsWith<CompilerException> {
-            C64Zeropage(CompilationOptions(OutputType.RAW, LauncherType.NONE, ZeropageType.KERNALSAFE, emptyList(), true))
+            C64Zeropage(CompilationOptions(OutputType.RAW, LauncherType.NONE, ZeropageType.KERNALSAFE, emptyList(), true, false))
         }
     }
 
     @Test
     fun testZpDontuse() {
-        val zp = C64Zeropage(CompilationOptions(OutputType.RAW, LauncherType.NONE, ZeropageType.DONTUSE, emptyList(), false))
+        val zp = C64Zeropage(CompilationOptions(OutputType.RAW, LauncherType.NONE, ZeropageType.DONTUSE, emptyList(), false, false))
         println(zp.free)
         assertEquals(0, zp.available())
         assertFailsWith<CompilerException> {
@@ -182,19 +185,19 @@ class TestC64Zeropage {
 
     @Test
     fun testFreeSpaces() {
-        val zp1 = C64Zeropage(CompilationOptions(OutputType.RAW, LauncherType.NONE, ZeropageType.BASICSAFE, emptyList(), true))
+        val zp1 = C64Zeropage(CompilationOptions(OutputType.RAW, LauncherType.NONE, ZeropageType.BASICSAFE, emptyList(), true, false))
         assertEquals(16, zp1.available())
-        val zp2 = C64Zeropage(CompilationOptions(OutputType.RAW, LauncherType.NONE, ZeropageType.FLOATSAFE, emptyList(), false))
+        val zp2 = C64Zeropage(CompilationOptions(OutputType.RAW, LauncherType.NONE, ZeropageType.FLOATSAFE, emptyList(), false, false))
         assertEquals(89, zp2.available())
-        val zp3 = C64Zeropage(CompilationOptions(OutputType.RAW, LauncherType.NONE, ZeropageType.KERNALSAFE, emptyList(), false))
+        val zp3 = C64Zeropage(CompilationOptions(OutputType.RAW, LauncherType.NONE, ZeropageType.KERNALSAFE, emptyList(), false, false))
         assertEquals(125, zp3.available())
-        val zp4 = C64Zeropage(CompilationOptions(OutputType.RAW, LauncherType.NONE, ZeropageType.FULL, emptyList(), false))
+        val zp4 = C64Zeropage(CompilationOptions(OutputType.RAW, LauncherType.NONE, ZeropageType.FULL, emptyList(), false, false))
         assertEquals(238, zp4.available())
     }
 
     @Test
     fun testReservedSpace() {
-        val zp1 = C64Zeropage(CompilationOptions(OutputType.RAW, LauncherType.NONE, ZeropageType.FULL, emptyList(), false))
+        val zp1 = C64Zeropage(CompilationOptions(OutputType.RAW, LauncherType.NONE, ZeropageType.FULL, emptyList(), false, false))
         assertEquals(238, zp1.available())
         assertTrue(50 in zp1.free)
         assertTrue(100 in zp1.free)
@@ -203,7 +206,7 @@ class TestC64Zeropage {
         assertTrue(200 in zp1.free)
         assertTrue(255 in zp1.free)
         assertTrue(199 in zp1.free)
-        val zp2 = C64Zeropage(CompilationOptions(OutputType.RAW, LauncherType.NONE, ZeropageType.FULL, listOf(50 .. 100, 200..255), false))
+        val zp2 = C64Zeropage(CompilationOptions(OutputType.RAW, LauncherType.NONE, ZeropageType.FULL, listOf(50 .. 100, 200..255), false, false))
         assertEquals(139, zp2.available())
         assertFalse(50 in zp2.free)
         assertFalse(100 in zp2.free)
@@ -216,7 +219,7 @@ class TestC64Zeropage {
 
     @Test
     fun testBasicsafeAllocation() {
-        val zp = C64Zeropage(CompilationOptions(OutputType.RAW, LauncherType.NONE, ZeropageType.BASICSAFE, emptyList(), true))
+        val zp = C64Zeropage(CompilationOptions(OutputType.RAW, LauncherType.NONE, ZeropageType.BASICSAFE, emptyList(), true, false))
         assertEquals(16, zp.available())
 
         assertFailsWith<ZeropageDepletedError> {
@@ -239,7 +242,7 @@ class TestC64Zeropage {
 
     @Test
     fun testFullAllocation() {
-        val zp = C64Zeropage(CompilationOptions(OutputType.RAW, LauncherType.NONE, ZeropageType.FULL, emptyList(), false))
+        val zp = C64Zeropage(CompilationOptions(OutputType.RAW, LauncherType.NONE, ZeropageType.FULL, emptyList(), false, false))
         assertEquals(238, zp.available())
         val loc = zp.allocate("", DataType.UWORD, null, errors)
         assertTrue(loc > 3)
@@ -269,7 +272,7 @@ class TestC64Zeropage {
 
     @Test
     fun testEfficientAllocation() {
-        val zp = C64Zeropage(CompilationOptions(OutputType.RAW, LauncherType.NONE, ZeropageType.BASICSAFE, emptyList(),  true))
+        val zp = C64Zeropage(CompilationOptions(OutputType.RAW, LauncherType.NONE, ZeropageType.BASICSAFE, emptyList(),  true, false))
         assertEquals(16, zp.available())
         assertEquals(0x04, zp.allocate("", DataType.WORD, null, errors))
         assertEquals(0x06, zp.allocate("", DataType.UBYTE, null, errors))
@@ -379,3 +382,169 @@ class TestPetscii {
         assertFalse(abc!=abc)
     }
 }
+
+
+class TestMemory {
+    @Test
+    fun testInValidRamC64_memory_addresses() {
+        CompilationTarget.instance = C64Target
+
+        var memexpr = NumericLiteralValue.optimalInteger(0x0000, Position.DUMMY)
+        var target = AssignTarget(null, null, DirectMemoryWrite(memexpr, Position.DUMMY), Position.DUMMY)
+        var scope = AnonymousScope(mutableListOf(), Position.DUMMY)
+        assertTrue(target.isInRegularRAM(scope))
+
+        memexpr = NumericLiteralValue.optimalInteger(0x1000, Position.DUMMY)
+        target = AssignTarget(null, null, DirectMemoryWrite(memexpr, Position.DUMMY), Position.DUMMY)
+        scope = AnonymousScope(mutableListOf(), Position.DUMMY)
+        assertTrue(target.isInRegularRAM(scope))
+
+        memexpr = NumericLiteralValue.optimalInteger(0x9fff, Position.DUMMY)
+        target = AssignTarget(null, null, DirectMemoryWrite(memexpr, Position.DUMMY), Position.DUMMY)
+        scope = AnonymousScope(mutableListOf(), Position.DUMMY)
+        assertTrue(target.isInRegularRAM(scope))
+
+        memexpr = NumericLiteralValue.optimalInteger(0xc000, Position.DUMMY)
+        target = AssignTarget(null, null, DirectMemoryWrite(memexpr, Position.DUMMY), Position.DUMMY)
+        scope = AnonymousScope(mutableListOf(), Position.DUMMY)
+        assertTrue(target.isInRegularRAM(scope))
+
+        memexpr = NumericLiteralValue.optimalInteger(0xcfff, Position.DUMMY)
+        target = AssignTarget(null, null, DirectMemoryWrite(memexpr, Position.DUMMY), Position.DUMMY)
+        scope = AnonymousScope(mutableListOf(), Position.DUMMY)
+        assertTrue(target.isInRegularRAM(scope))
+    }
+
+    @Test
+    fun testNotInValidRamC64_memory_addresses() {
+        CompilationTarget.instance = C64Target
+
+        var memexpr = NumericLiteralValue.optimalInteger(0xa000, Position.DUMMY)
+        var target = AssignTarget(null, null, DirectMemoryWrite(memexpr, Position.DUMMY), Position.DUMMY)
+        var scope = AnonymousScope(mutableListOf(), Position.DUMMY)
+        assertFalse(target.isInRegularRAM(scope))
+
+        memexpr = NumericLiteralValue.optimalInteger(0xafff, Position.DUMMY)
+        target = AssignTarget(null, null, DirectMemoryWrite(memexpr, Position.DUMMY), Position.DUMMY)
+        scope = AnonymousScope(mutableListOf(), Position.DUMMY)
+        assertFalse(target.isInRegularRAM(scope))
+
+        memexpr = NumericLiteralValue.optimalInteger(0xd000, Position.DUMMY)
+        target = AssignTarget(null, null, DirectMemoryWrite(memexpr, Position.DUMMY), Position.DUMMY)
+        scope = AnonymousScope(mutableListOf(), Position.DUMMY)
+        assertFalse(target.isInRegularRAM(scope))
+
+        memexpr = NumericLiteralValue.optimalInteger(0xffff, Position.DUMMY)
+        target = AssignTarget(null, null, DirectMemoryWrite(memexpr, Position.DUMMY), Position.DUMMY)
+        scope = AnonymousScope(mutableListOf(), Position.DUMMY)
+        assertFalse(target.isInRegularRAM(scope))
+    }
+
+    @Test
+    fun testInValidRamC64_memory_identifiers() {
+        CompilationTarget.instance = C64Target
+        var target = createTestProgramForMemoryRefViaVar(0x1000, VarDeclType.VAR)
+        assertTrue(target.isInRegularRAM(target.definingScope()))
+        target = createTestProgramForMemoryRefViaVar(0xd020, VarDeclType.VAR)
+        assertFalse(target.isInRegularRAM(target.definingScope()))
+        target = createTestProgramForMemoryRefViaVar(0x1000, VarDeclType.CONST)
+        assertTrue(target.isInRegularRAM(target.definingScope()))
+        target = createTestProgramForMemoryRefViaVar(0xd020, VarDeclType.CONST)
+        assertFalse(target.isInRegularRAM(target.definingScope()))
+        target = createTestProgramForMemoryRefViaVar(0x1000, VarDeclType.MEMORY)
+        assertFalse(target.isInRegularRAM(target.definingScope()))
+    }
+
+    @Test
+    private fun createTestProgramForMemoryRefViaVar(address: Int, vartype: VarDeclType): AssignTarget {
+        val decl = VarDecl(vartype, DataType.BYTE, ZeropageWish.DONTCARE, null, "address", null, NumericLiteralValue.optimalInteger(address, Position.DUMMY), false, false, Position.DUMMY)
+        val memexpr = IdentifierReference(listOf("address"), Position.DUMMY)
+        val target = AssignTarget(null, null, DirectMemoryWrite(memexpr, Position.DUMMY), Position.DUMMY)
+        val assignment = Assignment(target, NumericLiteralValue.optimalInteger(0, Position.DUMMY), Position.DUMMY)
+        val subroutine = Subroutine("test", emptyList(), emptyList(), emptyList(), emptyList(), emptySet(), null, false, mutableListOf(decl, assignment), Position.DUMMY)
+        subroutine.linkParents(ParentSentinel)
+        return target
+    }
+
+    @Test
+    fun testInValidRamC64_memory_expression() {
+        CompilationTarget.instance = C64Target
+        val memexpr = PrefixExpression("+", NumericLiteralValue.optimalInteger(0x1000, Position.DUMMY), Position.DUMMY)
+        val target = AssignTarget(null, null, DirectMemoryWrite(memexpr, Position.DUMMY), Position.DUMMY)
+        val scope = AnonymousScope(mutableListOf(), Position.DUMMY)
+        assertFalse(target.isInRegularRAM(scope))
+    }
+
+    @Test
+    fun testInValidRamC64_variable() {
+        CompilationTarget.instance = C64Target
+        val decl = VarDecl(VarDeclType.VAR, DataType.BYTE, ZeropageWish.DONTCARE, null, "address", null, null, false, false, Position.DUMMY)
+        val target = AssignTarget(IdentifierReference(listOf("address"), Position.DUMMY), null, null, Position.DUMMY)
+        val assignment = Assignment(target, NumericLiteralValue.optimalInteger(0, Position.DUMMY), Position.DUMMY)
+        val subroutine = Subroutine("test", emptyList(), emptyList(), emptyList(), emptyList(), emptySet(), null, false, mutableListOf(decl, assignment), Position.DUMMY)
+        subroutine.linkParents(ParentSentinel)
+        assertTrue(target.isInRegularRAM(target.definingScope()))
+    }
+
+    @Test
+    fun testInValidRamC64_memmap_variable() {
+        CompilationTarget.instance = C64Target
+        val address = 0x1000
+        val decl = VarDecl(VarDeclType.MEMORY, DataType.UBYTE, ZeropageWish.DONTCARE, null, "address", null, NumericLiteralValue.optimalInteger(address, Position.DUMMY), false, false, Position.DUMMY)
+        val target = AssignTarget(IdentifierReference(listOf("address"), Position.DUMMY), null, null, Position.DUMMY)
+        val assignment = Assignment(target, NumericLiteralValue.optimalInteger(0, Position.DUMMY), Position.DUMMY)
+        val subroutine = Subroutine("test", emptyList(), emptyList(), emptyList(), emptyList(), emptySet(), null, false, mutableListOf(decl, assignment), Position.DUMMY)
+        subroutine.linkParents(ParentSentinel)
+        assertTrue(target.isInRegularRAM(target.definingScope()))
+    }
+
+    @Test
+    fun testNotInValidRamC64_memmap_variable() {
+        CompilationTarget.instance = C64Target
+        val address = 0xd020
+        val decl = VarDecl(VarDeclType.MEMORY, DataType.UBYTE, ZeropageWish.DONTCARE, null, "address", null, NumericLiteralValue.optimalInteger(address, Position.DUMMY), false, false, Position.DUMMY)
+        val target = AssignTarget(IdentifierReference(listOf("address"), Position.DUMMY), null, null, Position.DUMMY)
+        val assignment = Assignment(target, NumericLiteralValue.optimalInteger(0, Position.DUMMY), Position.DUMMY)
+        val subroutine = Subroutine("test", emptyList(), emptyList(), emptyList(), emptyList(), emptySet(), null, false, mutableListOf(decl, assignment), Position.DUMMY)
+        subroutine.linkParents(ParentSentinel)
+        assertFalse(target.isInRegularRAM(target.definingScope()))
+    }
+
+    @Test
+    fun testInValidRamC64_array() {
+        CompilationTarget.instance = C64Target
+        val decl = VarDecl(VarDeclType.VAR, DataType.ARRAY_UB, ZeropageWish.DONTCARE, null, "address", null, null, false, false, Position.DUMMY)
+        val arrayindexed = ArrayIndexedExpression(IdentifierReference(listOf("address"), Position.DUMMY), ArrayIndex(NumericLiteralValue.optimalInteger(1, Position.DUMMY), Position.DUMMY), Position.DUMMY)
+        val target = AssignTarget(null, arrayindexed, null, Position.DUMMY)
+        val assignment = Assignment(target, NumericLiteralValue.optimalInteger(0, Position.DUMMY), Position.DUMMY)
+        val subroutine = Subroutine("test", emptyList(), emptyList(), emptyList(), emptyList(), emptySet(), null, false, mutableListOf(decl, assignment), Position.DUMMY)
+        subroutine.linkParents(ParentSentinel)
+        assertTrue(target.isInRegularRAM(target.definingScope()))
+    }
+
+    @Test
+    fun testInValidRamC64_array_memmapped() {
+        CompilationTarget.instance = C64Target
+        val address = 0x1000
+        val decl = VarDecl(VarDeclType.MEMORY, DataType.ARRAY_UB, ZeropageWish.DONTCARE, null, "address", null, NumericLiteralValue.optimalInteger(address, Position.DUMMY), false, false, Position.DUMMY)
+        val arrayindexed = ArrayIndexedExpression(IdentifierReference(listOf("address"), Position.DUMMY), ArrayIndex(NumericLiteralValue.optimalInteger(1, Position.DUMMY), Position.DUMMY), Position.DUMMY)
+        val target = AssignTarget(null, arrayindexed, null, Position.DUMMY)
+        val assignment = Assignment(target, NumericLiteralValue.optimalInteger(0, Position.DUMMY), Position.DUMMY)
+        val subroutine = Subroutine("test", emptyList(), emptyList(), emptyList(), emptyList(), emptySet(), null, false, mutableListOf(decl, assignment), Position.DUMMY)
+        subroutine.linkParents(ParentSentinel)
+        assertTrue(target.isInRegularRAM(target.definingScope()))
+    }
+
+    @Test
+    fun testNotValidRamC64_array_memmapped() {
+        CompilationTarget.instance = C64Target
+        val address = 0xe000
+        val decl = VarDecl(VarDeclType.MEMORY, DataType.ARRAY_UB, ZeropageWish.DONTCARE, null, "address", null, NumericLiteralValue.optimalInteger(address, Position.DUMMY), false, false, Position.DUMMY)
+        val arrayindexed = ArrayIndexedExpression(IdentifierReference(listOf("address"), Position.DUMMY), ArrayIndex(NumericLiteralValue.optimalInteger(1, Position.DUMMY), Position.DUMMY), Position.DUMMY)
+        val target = AssignTarget(null, arrayindexed, null, Position.DUMMY)
+        val assignment = Assignment(target, NumericLiteralValue.optimalInteger(0, Position.DUMMY), Position.DUMMY)
+        val subroutine = Subroutine("test", emptyList(), emptyList(), emptyList(), emptyList(), emptySet(), null, false, mutableListOf(decl, assignment), Position.DUMMY)
+        subroutine.linkParents(ParentSentinel)
+        assertFalse(target.isInRegularRAM(target.definingScope()))
+    }
+}

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

@@ -236,12 +236,15 @@ The largest 5-byte MFLPT float that can be stored is: **1.7014118345e+38**   (ne
 
 Arrays
 ^^^^^^
-Array types are also supported. They can be made of bytes, words or floats::
+Array types are also supported. They can be made of bytes, words or floats, strings, and other arrays
+(although the usefulness of the latter is very limited for now)::
 
     byte[10]  array                   ; array of 10 bytes, initially set to 0
     byte[]  array = [1, 2, 3, 4]      ; initialize the array, size taken from value
     byte[99] array = 255              ; initialize array with 99 times 255 [255, 255, 255, 255, ...]
     byte[] array = 100 to 199         ; initialize array with [100, 101, ..., 198, 199]
+    str[] names = ["ally", "pete"]    ; array of string pointers/addresses (equivalent to uword)
+    uword[] others = [names, array]   ; array of pointers/addresses to other arrays
 
     value = array[3]            ; the fourth value in the array (index is 0-based)
     char = string[4]            ; the fifth character (=byte) in the string
@@ -257,6 +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::
@@ -284,7 +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
@@ -293,6 +301,18 @@ large enough to contain the new value::
     string1 = "new value"
 
 
+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
+    that require a string as an argument.
+
 .. caution::
     It's probably best to avoid changing strings after they've been created. This
     includes changing certain letters by index, or by assigning a new value, or by
@@ -327,7 +347,7 @@ and then create a variable with it::
         ubyte blue
     }
 
-    Color rgb = {255,122,0}     ; note the curly braces here instead of brackets
+    Color rgb = [255,122,0]     ; note that struct initializer value is same as an array
     Color another               ; the init value is optional, like arrays
 
     another = rgb           ; assign all of the values of rgb to another
@@ -718,7 +738,7 @@ sort(array)
     floating point values.
 
 reverse(array)
-    Reverse the values in the array (in-place). Supports all data types including floats.
+    Reverse the values in the array (in-place).
     Can be used after sort() to sort an array in descending order.
 
 len(x)

docs/source/syntaxreference.rst

@@ -67,7 +67,8 @@ Directives
     - style ``kernalsafe`` -- use the part of the ZP that is 'free' or only used by BASIC routines,
       and don't change anything else.  This allows full use of KERNAL ROM routines (but not BASIC routines),
       including default IRQs during normal system operation.
-      When the program exits, a system reset is performed (because BASIC will be in a corrupt state).
+      It's not possible to return cleanly to BASIC when the program exits. The only choice is
+      to perform a system reset. (A ``system_reset`` subroutine is available in the syslib to help you do this)
     - style ``floatsafe`` -- like the previous one but also reserves the addresses that
       are required to perform floating point operations (from the BASIC kernel). No clean exit is possible.
     - style ``basicsafe`` -- the most restricted mode; only use the handful 'free' addresses in the ZP, and don't
@@ -77,10 +78,11 @@ 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``.
-      As with ``kernalsafe``, it is not possible to cleanly exit the program, other than to reset the machine.
+      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
+      to perform a system reset. (A ``system_reset`` subroutine is available in the syslib to help you do this)
     - style ``dontuse`` -- don't use *any* location in the zeropage.
 
     Also read :ref:`zeropage`.
@@ -117,33 +119,38 @@ Directives
 
 	Level: module, block.
 	Sets special compiler options.
-	For a module option, only the ``enable_floats`` option is recognised, which will tell the compiler
-	to deal with floating point numbers (by using various subroutines from the Commodore-64 kernal).
-	Otherwise, floating point support is not enabled.
-	When used in a block with the ``force_output`` option, it will force the block to be outputted
-	in the final program. Can be useful to make sure some
-	data is generated that would otherwise be discarded because it's not referenced (such as sprite data).
+
+    - For a module option, there is ``enable_floats``, which will tell the compiler
+      to deal with floating point numbers (by using various subroutines from the Commodore-64 kernal).
+      Otherwise, floating point support is not enabled.
+    - There's also ``no_sysinit`` which cause the resulting program to *not* include
+      the system re-initialization logic of clearing the screen, resetting I/O config etc. You'll have to
+      take care of that yourself. The program will just start running from whatever state the machine is in when the
+      program was launched.
+    - When used in a block with the ``force_output`` option, it will force the block to be outputted
+      in the final program. Can be useful to make sure some
+      data is generated that would otherwise be discarded because it's not referenced (such as sprite data).
 
 
 .. data:: %asmbinary "<filename>" [, <offset>[, <length>]]
 
-	Level: block.
-        This directive can only be used inside a block.
-        The assembler will include the file as binary bytes at this point, prog8 will not process this at all.
-        The optional offset and length can be used to select a particular piece of the file.
-        The file is located relative to the current working directory!
+    Level: block.
+    This directive can only be used inside a block.
+    The assembler will include the file as binary bytes at this point, prog8 will not process this at all.
+    The optional offset and length can be used to select a particular piece of the file.
+    The file is located relative to the current working directory!
 
 .. data:: %asminclude "<filename>", "scopelabel"
 
-	Level: block.
-        This directive can only be used inside a block.
-        The assembler will include the file as raw assembly source text at this point,
-        prog8 will not process this at all, with one exception: the labels.
-        The scopelabel argument will be used as a prefix to access the labels from the included source code,
-        otherwise you would risk symbol redefinitions or duplications.
-        If you know what you are doing you can leave it as an empty string to not have a scope prefix.
-        The compiler first looks for the file relative to the same directory as the module containing this statement is in,
-        if the file can't be found there it is searched relative to the current directory.
+    Level: block.
+    This directive can only be used inside a block.
+    The assembler will include the file as raw assembly source text at this point,
+    prog8 will not process this at all, with one exception: the labels.
+    The scopelabel argument will be used as a prefix to access the labels from the included source code,
+    otherwise you would risk symbol redefinitions or duplications.
+    If you know what you are doing you can leave it as an empty string to not have a scope prefix.
+    The compiler first looks for the file relative to the same directory as the module containing this statement is in,
+    if the file can't be found there it is searched relative to the current directory.
 
 .. data:: %breakpoint
 
@@ -274,6 +281,7 @@ type identifier  type                     storage size       example var declara
 ``word[]``       signed word array        depends on value   ``word[] myvar = [1, 2, 3, 4]``
 ``uword[]``      unsigned word array      depends on value   ``uword[] myvar = [1, 2, 3, 4]``
 ``float[]``      floating-point array     depends on value   ``float[] myvar = [1.1, 2.2, 3.3, 4.4]``
+``str[]``        array with string ptrs   2*x bytes + strs   ``str[] names = ["ally", "pete"]``
 ``str``          string (petscii)         varies             ``str myvar = "hello."``
                                                              implicitly terminated by a 0-byte
 ===============  =======================  =================  =========================================
@@ -391,7 +399,25 @@ After defining a struct you can use the name of the struct as a data type to dec
 
 Struct variables can be assigned a struct literal value (also in their declaration as initial value)::
 
-    Color rgb = {255, 100, 0}          ; curly braces instead of brackets
+    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
@@ -478,6 +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.
@@ -485,9 +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

@@ -3,31 +3,23 @@ TODO
 ====
 
 - get rid of all other TODO's in the code ;-)
-- move the 	ldx  #$ff | clc | cld  from the startup logic into the start() function as first instructions
-- add an %option that omits the 'system-init' code at the start. Useful to create separate standalone routines that shouldn't re-init the whole machine every time they're called
-- line-circle-gfx examples are now a few hundred bytes larger than before. Why is that, can it be fixed?
-- until condition should be able to refer to variables defined IN the do-until block itself.
-- add support? example? for processing arguments to a sys call : sys 999, 1, 2, "aaa"
-- make it possible for array literals to not only contain compile time constants
-- further optimize assignment codegeneration
 - 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)
 - see if we can group some errors together for instance the (now single) errors about unidentified symbols
 - use VIC banking to move up the graphics bitmap memory location. Don't move it under the ROM though as that would require IRQ disabling and memory bank swapping for every bitmap manipulation
-- add some primitives/support/examples for using custom char sets, copying the default charset.
+- add some primitives/subroutines/examples for using custom char sets, copying the default charset.
+- recursive subroutines? via %option recursive, allocate all params and local vars on estack, don't allow nested subroutines, can begin by first not allowing any local variables just fixing the parameters
 
 More optimizations
 ^^^^^^^^^^^^^^^^^^
 
 Add more compiler optimizations to the existing ones.
 
-- more targeted optimizations for assigment asm code, such as the following:
-- subroutine calling convention? like: 1 byte arg -> pass in A, 2 bytes -> pass in A+Y, return value likewise.
+- 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.  Especially for built-in functions!
 - can such parameter passing to subroutines be optimized to avoid copying?
-- add a compiler option to not include variable initialization code (useful if the program is expected to run only once, such as a game)
-  the program will then rely solely on the values as they are in memory at the time of program startup.
-- Also some library routines and code patterns could perhaps be optimized further
 - more optimizations on the language AST level
 - more optimizations on the final assembly source level
 - note: subroutine inlining is abandoned because of problems referencing non-local stuff. Can't move everything around.

examples/arithmetic/wordbyte.p8

@@ -0,0 +1,315 @@
+%import textio
+%import syslib
+%zeropage basicsafe
+
+
+main {
+    sub start() {
+        repeat 25 {
+            txt.chrout('\n')
+        }
+
+        ubyte ub
+        byte bb
+        uword uwsum
+        word wsum
+
+        uwsum = 50000
+        ub=50
+        uwsum += ub
+        ub=250
+        uwsum += ub
+
+        if uwsum==50300
+            txt.print("1 ok\n")
+        else {
+            txt.print("1 fail:")
+            txt.print_uw(uwsum)
+            txt.chrout('\n')
+        }
+
+        wsum  = -30000
+        bb = 100
+        wsum += bb
+        bb = -50
+        wsum += bb
+
+        if wsum==-29950
+            txt.print("2 ok\n")
+        else {
+            txt.print("2 fail:")
+            txt.print_w(wsum)
+            txt.chrout('\n')
+        }
+
+        uwsum = 50000
+        ub=50
+        uwsum -= ub
+        ub=250
+        uwsum -= ub
+
+        if uwsum==49700
+            txt.print("3 ok\n")
+        else {
+            txt.print("3 fail:")
+            txt.print_uw(uwsum)
+            txt.chrout('\n')
+        }
+        wsum  = -30000
+        bb = 100
+        wsum -= bb
+        bb = -50
+        wsum -= bb
+
+        if wsum==-30050
+            txt.print("4 ok\n")
+        else
+            txt.print("4 fail\n")
+
+
+
+        uwsum = 50000
+        bb=50
+        uwsum += bb as uword
+        bb=-100
+        uwsum += bb as uword
+
+        if uwsum==49950
+            txt.print("5 ok\n")
+        else
+            txt.print("5 fail\n")
+
+        uwsum = 50000
+        bb=50
+        uwsum -= bb as uword
+        bb=100
+        uwsum -= bb as uword
+
+        if uwsum==49850
+            txt.print("6 ok\n")
+        else {
+            txt.print("6 fail:")
+            txt.print_uw(uwsum)
+            txt.chrout('\n')
+        }
+
+        wsum  = -30000
+        ub = 50
+        wsum += ub
+        ub = 250
+        wsum += ub
+
+        if wsum==-29700
+            txt.print("7 ok\n")
+        else {
+            txt.print("7 fail:")
+            txt.print_w(wsum)
+            txt.chrout('\n')
+        }
+
+        wsum  = -30000
+        ub = 50
+        wsum -= ub
+        ub = 250
+        wsum -= ub
+
+        if wsum==-30300
+            txt.print("8 ok\n")
+        else {
+            txt.print("8 fail:")
+            txt.print_w(wsum)
+            txt.chrout('\n')
+        }
+
+        txt.chrout('\n')
+
+
+
+        uwsum = 50000
+        ub=0
+        uwsum += (50+ub)
+        uwsum += (250+ub)
+
+        if uwsum==50300
+            txt.print("1b ok\n")
+        else {
+            txt.print("1b fail:")
+            txt.print_uw(uwsum)
+            txt.chrout('\n')
+        }
+
+        bb = 0
+        wsum  = -30000
+        wsum += (100+bb)
+        wsum += (-50+bb)
+
+        if wsum==-29950
+            txt.print("2b ok\n")
+        else {
+            txt.print("2b fail:")
+            txt.print_w(wsum)
+            txt.chrout('\n')
+        }
+
+        uwsum = 50000
+        uwsum -= (50+ub)
+        uwsum -= (250+ub)
+
+        if uwsum==49700
+            txt.print("3b ok\n")
+        else {
+            txt.print("3b fail:")
+            txt.print_uw(uwsum)
+            txt.chrout('\n')
+        }
+        wsum  = -30000
+        wsum -= (100+bb)
+        wsum -= (-50+bb)
+
+        if wsum==-30050
+            txt.print("4b ok\n")
+        else
+            txt.print("4b fail\n")
+
+
+        uwsum = 50000
+        uwsum += (50+bb) as uword
+        uwsum += (-100+bb) as uword
+
+        if uwsum==49950
+            txt.print("5b ok\n")
+        else
+            txt.print("5b fail\n")
+
+        uwsum = 50000
+        uwsum -= (50+bb) as uword
+        uwsum -= (100+bb) as uword
+
+        if uwsum==49850
+            txt.print("6b ok\n")
+        else {
+            txt.print("6b fail:")
+            txt.print_uw(uwsum)
+            txt.chrout('\n')
+        }
+
+        wsum  = -30000
+        wsum += (50+ub)
+        wsum += (250+ub)
+
+        if wsum==-29700
+            txt.print("7b ok\n")
+        else {
+            txt.print("7b fail:")
+            txt.print_w(wsum)
+            txt.chrout('\n')
+        }
+
+        wsum  = -30000
+        wsum -= (50+ub)
+        wsum -= (250+ub)
+
+        if wsum==-30300
+            txt.print("8b ok\n")
+        else {
+            txt.print("8b fail:")
+            txt.print_w(wsum)
+            txt.chrout('\n')
+        }
+
+        txt.chrout('\n')
+
+
+
+        uwsum = 50000
+        uwsum += 50
+        uwsum += 250
+
+        if uwsum==50300
+            txt.print("1c ok\n")
+        else {
+            txt.print("1c fail:")
+            txt.print_uw(uwsum)
+            txt.chrout('\n')
+        }
+
+        wsum  = -30000
+        wsum += 100
+        wsum += -50
+
+        if wsum==-29950
+            txt.print("2c ok\n")
+        else {
+            txt.print("2c fail:")
+            txt.print_w(wsum)
+            txt.chrout('\n')
+        }
+
+        uwsum = 50000
+        uwsum -= 50
+        uwsum -= 250
+
+        if uwsum==49700
+            txt.print("3c ok\n")
+        else {
+            txt.print("3c fail:")
+            txt.print_uw(uwsum)
+            txt.chrout('\n')
+        }
+        wsum  = -30000
+        wsum -= 100
+        wsum -= -50
+
+        if wsum==-30050
+            txt.print("4c ok\n")
+        else
+            txt.print("4c fail\n")
+
+
+        uwsum = 50000
+        uwsum += 50 as uword
+        uwsum += -100 as uword
+
+        if uwsum==49950
+            txt.print("5c ok\n")
+        else
+            txt.print("5c fail\n")
+
+        uwsum = 50000
+        uwsum -= 50 as uword
+        uwsum -= 100 as uword
+
+        if uwsum==49850
+            txt.print("6c ok\n")
+        else {
+            txt.print("6c fail:")
+            txt.print_uw(uwsum)
+            txt.chrout('\n')
+        }
+
+        wsum  = -30000
+        wsum += 50
+        wsum += 250
+
+        if wsum==-29700
+            txt.print("7c ok\n")
+        else {
+            txt.print("7c fail:")
+            txt.print_w(wsum)
+            txt.chrout('\n')
+        }
+
+        wsum  = -30000
+        wsum -= 50
+        wsum -= 250
+
+        if wsum==-30300
+            txt.print("8c ok\n")
+        else {
+            txt.print("8c fail:")
+            txt.print_w(wsum)
+            txt.chrout('\n')
+        }
+    }
+
+}

examples/balloonflight.p8

@@ -45,7 +45,9 @@ main {
 
             perform_scroll = false
             txt.scroll_left(true)
-            if c64.RASTER & 1
+
+            ; float the balloon
+            if rnd() & %10000
                 c64.SPXY[1] ++
             else
                 c64.SPXY[1] --

examples/cmp/comparisons_byte.p8

@@ -1,95 +0,0 @@
-%import textio
-%zeropage basicsafe
-
-; Note: this program is compatible with C64 and CX16.
-
-main {
-
-    sub start()  {
-
-        byte v1
-        byte v2
-        ubyte cr
-
-        txt.print("signed byte ")
-
-        cr=v1==v2
-        cr=v1==v2
-        cr=v1==v2
-        cr=v1!=v2
-        cr=v1!=v2
-        cr=v1!=v2
-        cr=v1<v2
-        cr=v1<v2
-        cr=v1<v2
-        cr=v1<v2
-        cr=v1>v2
-        cr=v1>v2
-        cr=v1>v2
-        cr=v1>v2
-        cr=v1>v2
-        cr=v1<=v2
-        cr=v1<=v2
-        cr=v1<=v2
-        cr=v1<=v2
-        cr=v1>=v2
-        cr=v1>=v2
-        cr=v1>=v2
-        cr=v1>=v2
-        cr=v1>=v2
-
-        ; comparisons:
-        v1=-20
-        v2=125
-        txt.print("v1=-20, v2=125\n")
-        compare()
-
-        v1=80
-        v2=80
-        txt.print("v1 = v2 = 80\n")
-        compare()
-
-        v1=20
-        v2=-111
-        txt.print("v1=20, v2=-111\n")
-        compare()
-
-        return
-
-        sub compare() {
-        txt.print("  ==  !=  <   >   <=  >=\n")
-
-        if v1==v2
-            txt.print("  Q ")
-        else
-            txt.print("  . ")
-        if v1!=v2
-            txt.print("  Q ")
-        else
-            txt.print("  . ")
-
-        if v1<v2
-            txt.print("  Q ")
-        else
-            txt.print("  . ")
-
-        if v1>v2
-            txt.print("  Q ")
-        else
-            txt.print("  . ")
-
-        if v1<=v2
-            txt.print("  Q ")
-        else
-            txt.print("  . ")
-
-        if v1>=v2
-            txt.print("  Q ")
-        else
-            txt.print("  . ")
-        c64.CHROUT('\n')
-
-    }
-
-    }
-}

examples/cmp/comparisons_float.p8

@@ -1,112 +0,0 @@
-%import textio
-%import floats
-%zeropage basicsafe
-
-; Note: this program is compatible with C64 and CX16.
-
-main {
-
-    sub start()  {
-
-        float v1
-        float v2
-        ubyte cr
-
-        txt.print("floating point ")
-
-        cr=v1==v2
-        cr=v1==v2
-        cr=v1==v2
-        cr=v1!=v2
-        cr=v1!=v2
-        cr=v1!=v2
-        cr=v1<v2
-        cr=v1<v2
-        cr=v1<v2
-        cr=v1<v2
-        cr=v1>v2
-        cr=v1>v2
-        cr=v1>v2
-        cr=v1>v2
-        cr=v1>v2
-        cr=v1<=v2
-        cr=v1<=v2
-        cr=v1<=v2
-        cr=v1<=v2
-        cr=v1>=v2
-        cr=v1>=v2
-        cr=v1>=v2
-        cr=v1>=v2
-        cr=v1>=v2
-
-        ; comparisons:
-        v1=20
-        v2=666.66
-        txt.print("v1=20, v2=666.66\n")
-        compare()
-
-        v1=-20
-        v2=666.66
-        txt.print("v1=-20, v2=666.66\n")
-        compare()
-
-        v1=666.66
-        v2=555.55
-        txt.print("v1=666.66, v2=555.55\n")
-        compare()
-
-        v1=3.1415
-        v2=-3.1415
-        txt.print("v1 = 3.1415, v2 = -3.1415\n")
-        compare()
-
-        v1=3.1415
-        v2=3.1415
-        txt.print("v1 = v2 = 3.1415\n")
-        compare()
-
-        v1=0
-        v2=0
-        txt.print("v1 = v2 = 0\n")
-        compare()
-
-        return
-
-        sub compare() {
-        txt.print("  ==  !=  <   >   <=  >=\n")
-
-        if v1==v2
-            txt.print("  Q ")
-        else
-            txt.print("  . ")
-        if v1!=v2
-            txt.print("  Q ")
-        else
-            txt.print("  . ")
-
-        if v1<v2
-            txt.print("  Q ")
-        else
-            txt.print("  . ")
-
-        if v1>v2
-            txt.print("  Q ")
-        else
-            txt.print("  . ")
-
-        if v1<=v2
-            txt.print("  Q ")
-        else
-            txt.print("  . ")
-
-        if v1>=v2
-            txt.print("  Q ")
-        else
-            txt.print("  . ")
-        c64.CHROUT('\n')
-
-    }
-
-    }
-
-}

examples/cmp/comparisons_ubyte.p8

@@ -1,96 +0,0 @@
-%import textio
-%zeropage basicsafe
-
-; Note: this program is compatible with C64 and CX16.
-
-main {
-
-    sub start()  {
-
-        ubyte v1
-        ubyte v2
-        ubyte cr
-
-        txt.print("unsigned byte ")
-
-        cr=v1==v2
-        cr=v1==v2
-        cr=v1==v2
-        cr=v1!=v2
-        cr=v1!=v2
-        cr=v1!=v2
-        cr=v1<v2
-        cr=v1<v2
-        cr=v1<v2
-        cr=v1<v2
-        cr=v1>v2
-        cr=v1>v2
-        cr=v1>v2
-        cr=v1>v2
-        cr=v1>v2
-        cr=v1<=v2
-        cr=v1<=v2
-        cr=v1<=v2
-        cr=v1<=v2
-        cr=v1>=v2
-        cr=v1>=v2
-        cr=v1>=v2
-        cr=v1>=v2
-        cr=v1>=v2
-
-        ; comparisons:
-        v1=20
-        v2=199
-        txt.print("v1=20, v2=199\n")
-        compare()
-
-        v1=80
-        v2=80
-        txt.print("v1 = v2 = 80\n")
-        compare()
-
-        v1=220
-        v2=10
-        txt.print("v1=220, v2=10\n")
-        compare()
-
-        return
-
-        sub compare() {
-        txt.print("  ==  !=  <   >   <=  >=\n")
-
-        if v1==v2
-            txt.print("  Q ")
-        else
-            txt.print("  . ")
-        if v1!=v2
-            txt.print("  Q ")
-        else
-            txt.print("  . ")
-
-        if v1<v2
-            txt.print("  Q ")
-        else
-            txt.print("  . ")
-
-        if v1>v2
-            txt.print("  Q ")
-        else
-            txt.print("  . ")
-
-        if v1<=v2
-            txt.print("  Q ")
-        else
-            txt.print("  . ")
-
-        if v1>=v2
-            txt.print("  Q ")
-        else
-            txt.print("  . ")
-        c64.CHROUT('\n')
-
-    }
-
-    }
-
-}

examples/cmp/comparisons_uword.p8

@@ -1,125 +0,0 @@
-%import textio
-%zeropage basicsafe
-
-; Note: this program is compatible with C64 and CX16.
-
-main {
-
-    sub start()  {
-
-        uword v1
-        uword v2
-        ubyte cr
-
-        txt.print("unsigned word ")
-
-        cr=v1==v2
-        cr=v1==v2
-        cr=v1==v2
-        cr=v1!=v2
-        cr=v1!=v2
-        cr=v1!=v2
-        cr=v1<v2
-        cr=v1<v2
-        cr=v1<v2
-        cr=v1<v2
-        cr=v1>v2
-        cr=v1>v2
-        cr=v1>v2
-        cr=v1>v2
-        cr=v1>v2
-        cr=v1<=v2
-        cr=v1<=v2
-        cr=v1<=v2
-        cr=v1<=v2
-        cr=v1>=v2
-        cr=v1>=v2
-        cr=v1>=v2
-        cr=v1>=v2
-        cr=v1>=v2
-
-        ; comparisons:
-        v1=20
-        v2=$00aa
-        txt.print("v1=20, v2=$00aa\n")
-        compare()
-
-        v1=20
-        v2=$ea00
-        txt.print("v1=20, v2=$ea00\n")
-        compare()
-
-        v1=$c400
-        v2=$22
-        txt.print("v1=$c400, v2=$22\n")
-        compare()
-
-        v1=$c400
-        v2=$2a00
-        txt.print("v1=$c400, v2=$2a00\n")
-        compare()
-
-        v1=$c433
-        v2=$2a00
-        txt.print("v1=$c433, v2=$2a00\n")
-        compare()
-
-        v1=$c433
-        v2=$2aff
-        txt.print("v1=$c433, v2=$2aff\n")
-        compare()
-
-        v1=$aabb
-        v2=$aabb
-        txt.print("v1 = v2 = aabb\n")
-        compare()
-
-        v1=$aa00
-        v2=$aa00
-        txt.print("v1 = v2 = aa00\n")
-        compare()
-
-        v1=$aa
-        v2=$aa
-        txt.print("v1 = v2 = aa\n")
-        compare()
-
-        return
-
-        sub compare() {
-        txt.print("  ==  !=  <   >   <=  >=\n")
-
-        if v1==v2
-            txt.print("  Q ")
-        else
-            txt.print("  . ")
-        if v1!=v2
-            txt.print("  Q ")
-        else
-            txt.print("  . ")
-
-        if v1<v2
-            txt.print("  Q ")
-        else
-            txt.print("  . ")
-
-        if v1>v2
-            txt.print("  Q ")
-        else
-            txt.print("  . ")
-
-        if v1<=v2
-            txt.print("  Q ")
-        else
-            txt.print("  . ")
-
-        if v1>=v2
-            txt.print("  Q ")
-        else
-            txt.print("  . ")
-        c64.CHROUT('\n')
-
-    }
-
-    }
-}

examples/cmp/comparisons_word.p8

@@ -1,161 +0,0 @@
-%import textio
-%zeropage basicsafe
-
-; Note: this program is compatible with C64 and CX16.
-
-main {
-
-    sub start()  {
-
-        word v1
-        word v2
-        ubyte cr
-
-        txt.print("signed word ")
-
-        cr=v1==v2
-        cr=v1==v2
-        cr=v1==v2
-        cr=v1!=v2
-        cr=v1!=v2
-        cr=v1!=v2
-        cr=v1<v2
-        cr=v1<v2
-        cr=v1<v2
-        cr=v1<v2
-        cr=v1>v2
-        cr=v1>v2
-        cr=v1>v2
-        cr=v1>v2
-        cr=v1>v2
-        cr=v1<=v2
-        cr=v1<=v2
-        cr=v1<=v2
-        cr=v1<=v2
-        cr=v1>=v2
-        cr=v1>=v2
-        cr=v1>=v2
-        cr=v1>=v2
-        cr=v1>=v2
-
-        ; comparisons:
-        v1=20
-        v2=$00aa
-        txt.print("v1=20, v2=$00aa\n")
-        compare()
-
-        v1=20
-        v2=$7a00
-        txt.print("v1=20, v2=$7a00\n")
-        compare()
-
-        v1=$7400
-        v2=$22
-        txt.print("v1=$7400, v2=$22\n")
-        compare()
-
-        v1=$7400
-        v2=$2a00
-        txt.print("v1=$7400, v2=$2a00\n")
-        compare()
-
-        v1=$7433
-        v2=$2a00
-        txt.print("v1=$7433, v2=$2a00\n")
-        compare()
-
-        v1=$7433
-        v2=$2aff
-        txt.print("v1=$7433, v2=$2aff\n")
-        compare()
-
-        ;  with negative numbers:
-        v1=-512
-        v2=$00aa
-        txt.print("v1=-512, v2=$00aa\n")
-        compare()
-
-        v1=-512
-        v2=$7a00
-        txt.print("v1=-512, v2=$7a00\n")
-        compare()
-
-        v1=$7400
-        v2=-512
-        txt.print("v1=$7400, v2=-512\n")
-        compare()
-
-        v1=-20000
-        v2=-1000
-        txt.print("v1=-20000, v2=-1000\n")
-        compare()
-
-        v1=-1000
-        v2=-20000
-        txt.print("v1=-1000, v2=-20000\n")
-        compare()
-
-        v1=-1
-        v2=32767
-        txt.print("v1=-1, v2=32767\n")
-        compare()
-
-        v1=32767
-        v2=-1
-        txt.print("v1=32767, v2=-1\n")
-        compare()
-
-        v1=$7abb
-        v2=$7abb
-        txt.print("v1 = v2 = 7abb\n")
-        compare()
-
-        v1=$7a00
-        v2=$7a00
-        txt.print("v1 = v2 = 7a00\n")
-        compare()
-
-        v1=$aa
-        v2=$aa
-        txt.print("v1 = v2 = aa\n")
-        compare()
-
-        return
-
-        sub compare() {
-        txt.print("  ==  !=  <   >   <=  >=\n")
-
-        if v1==v2
-            txt.print("  Q ")
-        else
-            txt.print("  . ")
-        if v1!=v2
-            txt.print("  Q ")
-        else
-            txt.print("  . ")
-
-        if v1<v2
-            txt.print("  Q ")
-        else
-            txt.print("  . ")
-
-        if v1>v2
-            txt.print("  Q ")
-        else
-            txt.print("  . ")
-
-        if v1<=v2
-            txt.print("  Q ")
-        else
-            txt.print("  . ")
-
-        if v1>=v2
-            txt.print("  Q ")
-        else
-            txt.print("  . ")
-        c64.CHROUT('\n')
-
-    }
-
-    }
-}

examples/cube3d-sprites.p8

@@ -2,7 +2,6 @@
 %import syslib
 %import textio
 
-
 spritedata $2000 {
     ; this memory block contains the sprite data
     ; it must start on an address aligned to 64 bytes.

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

@@ -2,6 +2,7 @@
 %import textio
 %import syslib
 %zeropage basicsafe
+%option no_sysinit
 %launcher none
 %address 50000
 
@@ -9,38 +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