c64/c128 targets: perform cleanup at program exit such as re-enabling run-stop key and character set switching.

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

@@ -127,9 +127,27 @@ internal class ProgramAndVarsGen(
             "cx16" -> {
                 if(options.floats)
                     asmgen.out("  lda  #4 |  sta  $01")    // to use floats, make sure Basic rom is banked in
-                asmgen.out("  jsr  main.start |  lda  #4 |  sta  $01 |  rts")
+                asmgen.out("  jsr  main.start |  lda  #4 |  sta  $01")
+                if(!options.noSysInit)
+                    asmgen.out("  jmp  ${compTarget.name}.cleanup_at_exit")
+                else
+                    asmgen.out("  rts")
+            }
+            "c64" -> {
+                asmgen.out("  jsr  main.start |  lda  #31 |  sta  $01")
+                if(!options.noSysInit)
+                    asmgen.out("  jmp  ${compTarget.name}.cleanup_at_exit")
+                else
+                    asmgen.out("  rts")
+            }
+            "c128" -> {
+                asmgen.out("  jsr  main.start")
+                // TODO c128: how to bank basic+kernal back in?
+                if(!options.noSysInit)
+                    asmgen.out("  jmp  ${compTarget.name}.cleanup_at_exit")
+                else
+                    asmgen.out("  rts")
             }
-            "c64" -> asmgen.out("  jsr  main.start |  lda  #31 |  sta  $01 |  rts")
             else -> asmgen.jmp("main.start")
         }
     }

compiler/res/prog8lib/c128/syslib.p8

@@ -274,6 +274,16 @@ asmsub  disable_runstop_and_charsetswitch() clobbers(A) {
     }}
 }
 
+asmsub  enable_runstop_and_charsetswitch() clobbers(A) {
+    %asm {{
+        lda  #0
+        sta  247    ; enable charset switching
+        lda  #110
+        sta  808    ; enable run/stop key
+        rts
+    }}
+}
+
 asmsub  set_irq(uword handler @AY, ubyte useKernal @Pc) clobbers(A)  {
 	%asm {{
 	        sta  _modified+1
@@ -481,6 +491,13 @@ asmsub  init_system_phase2()  {
     }}
 }
 
+asmsub  cleanup_at_exit() {
+    ; executed when the main subroutine does rts
+    %asm {{
+        jmp  c64.enable_runstop_and_charsetswitch
+    }}
+}
+
 asmsub  disable_basic() clobbers(A) {
     %asm {{
         lda $0a04   ; disable BASIC shadow registers
@@ -681,7 +698,10 @@ _longcopy
     inline asmsub exit(ubyte returnvalue @A) {
         ; -- immediately exit the program with a return code in the A register
         %asm {{
+            ;lda  #14
+            ;sta  $01        ; bank the kernal in       TODO c128 how to do this?
             jsr  c64.CLRCHN		; reset i/o channels
+            jsr  c64.enable_runstop_and_charsetswitch
             ldx  prog8_lib.orig_stackpointer
             txs
             rts		; return to original caller

compiler/res/prog8lib/c64/syslib.p8

@@ -300,6 +300,13 @@ asmsub  init_system_phase2()  {
     }}
 }
 
+asmsub  cleanup_at_exit() {
+    ; executed when the main subroutine does rts
+    %asm {{
+        jmp  c64.enable_runstop_and_charsetswitch
+    }}
+}
+
 asmsub  disable_runstop_and_charsetswitch() clobbers(A) {
     %asm {{
         lda  #$80
@@ -310,6 +317,16 @@ asmsub  disable_runstop_and_charsetswitch() clobbers(A) {
     }}
 }
 
+asmsub  enable_runstop_and_charsetswitch() clobbers(A) {
+    %asm {{
+        lda  #0
+        sta  657    ; enable charset switching
+        lda  #237
+        sta  808    ; enable run/stop key
+        rts
+    }}
+}
+
 asmsub  set_irq(uword handler @AY, ubyte useKernal @Pc) clobbers(A)  {
 	%asm {{
 	        sta  _modified+1
@@ -646,7 +663,10 @@ _longcopy
     inline asmsub exit(ubyte returnvalue @A) {
         ; -- immediately exit the program with a return code in the A register
         %asm {{
+            lda  #31
+            sta  $01        ; bank the kernal in
             jsr  c64.CLRCHN		; reset i/o channels
+            jsr  c64.enable_runstop_and_charsetswitch
             ldx  prog8_lib.orig_stackpointer
             txs
             rts		; return to original caller

compiler/res/prog8lib/cx16/syslib.p8

@@ -641,6 +641,14 @@ asmsub  init_system_phase2()  {
     }}
 }
 
+asmsub  cleanup_at_exit() {
+    ; executed when the main subroutine does rts
+    ; just an rts here, nothing special to clean up on cx16
+    %asm {{
+        rts
+    }}
+}
+
 asmsub  set_irq(uword handler @AY, ubyte useKernal @Pc) clobbers(A)  {
 	%asm {{
 	        sta  _modified+1

docs/source/todo.rst

@@ -3,7 +3,6 @@ TODO
 
 For next release
 ^^^^^^^^^^^^^^^^
-- c64 target: after exit, switching charset case is still disabled. Don't disable this by default in startup?
 - vm: check array type in PtAssignTarget
 - vm: animals example game breaks after adding first new animal...
 - vm: add more instructions operating directly on memory instead of only registers? (translate assignment self-assigns)

examples/tehtriz.p8

@@ -32,7 +32,6 @@ main {
 
 
     sub start() {
-        c64.disable_runstop_and_charsetswitch()
         ;@(650) = 128        ; set all keys to repeat
         sound.init()
         newGame()

examples/test.p8

@@ -31,7 +31,9 @@ main {
 
         txt.print(name)
         txt.nl()
-        name=other
+        uword otherptr = &other + 2
+        name = otherptr
+
         txt.print(name)
         txt.nl()
         txt.nl()