fix clobbering of A when restoring X or Y from stack

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

@@ -584,16 +584,16 @@ internal class AsmGen(private val program: Program,
                 CpuRegister.A -> out("  pla")
                 CpuRegister.X -> {
                     if (CompilationTarget.instance.machine.cpu == CpuType.CPU65c02) out("  plx")
-                    else out("  pla |  tax")
+                    else out("  sta  P8ZP_SCRATCH_REG |  pla |  tax |  lda  P8ZP_SCRATCH_REG")
                 }
                 CpuRegister.Y -> {
                     if (CompilationTarget.instance.machine.cpu == CpuType.CPU65c02) out("  ply")
-                    else out("  pla |  tay")
+                    else out("  sta  P8ZP_SCRATCH_REG |  pla |  tay |  lda  P8ZP_SCRATCH_REG")
                 }
             }
         } else {
             when (register) {
-                CpuRegister.A -> out("  sta  _prog8_regsaveA")
+                CpuRegister.A -> out("  lda  _prog8_regsaveA")
                 CpuRegister.X -> out("  ldx  _prog8_regsaveX")
                 CpuRegister.Y -> out("  ldy  _prog8_regsaveY")
             }

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

@@ -25,8 +25,9 @@ internal class FunctionCallAsmGen(private val program: Program, private val asmg
         // 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 = sub.shouldSaveX()
+        val regSaveOnStack = sub.asmAddress==null       // rom-routines don't require registers to be saved on stack, normal subroutines do because they can contain nested calls
         if(saveX)
-            asmgen.saveRegister(CpuRegister.X, (stmt as Node).definingSubroutine()!!, true)
+            asmgen.saveRegister(CpuRegister.X, (stmt as Node).definingSubroutine()!!, regSaveOnStack)
 
         val subName = asmgen.asmSymbolName(stmt.target)
         if(stmt.args.isNotEmpty()) {
@@ -64,7 +65,7 @@ internal class FunctionCallAsmGen(private val program: Program, private val asmg
         }
         asmgen.out("  jsr  $subName")
         if(saveX)
-            asmgen.restoreRegister(CpuRegister.X, true)
+            asmgen.restoreRegister(CpuRegister.X, regSaveOnStack)
     }
 
     private fun registerArgsViaStackEvaluation(stmt: IFunctionCall, sub: Subroutine) {

examples/cx16/imageviewer/imageviewer.p8

@@ -8,6 +8,8 @@
 %import bmp_module
 ;; %import ci_module
 
+; TODO WHY is this 400 bytes larger than a few hours ago?
+
 main {
     sub start() {
         ; trick to check if we're running on sdcard or host system shared folder

examples/tehtriz.p8

@@ -7,8 +7,6 @@
 ;   staged speed increase
 ;   some simple sound effects
 
-; TODO BROKEN: DOESN'T REGISTER KEYSTROKES ANYMORE (CAN'T START GAME)
-
 
 %target c64
 %import syslib

examples/test.p8

@@ -71,9 +71,13 @@ _y  .byte 0
 
     sub start () {
 
-                while c64.CHRIN() {
+        txt.print("status 8: ")
-                    ; read the rest of the entry until the end
+        uword ss = diskio.status(8)
-                }
+        txt.print(ss)
+        txt.print("\nstatus 9: ")
+        ss = diskio.status(9)
+        txt.print(ss)
+        txt.chrout('\n')
 
 ;        cx16.r0 = 65535
 ;        set_8_pixels_opaque_OLD(111,222,33)

examples/textelite.p8

@@ -10,9 +10,6 @@
 
 ; Note: this program is compatible with C64 and CX16.
 
-; TODO BROKEN IN VICE WHEN LOADING WITHOUT DISK: PRINTS WEIRD CHARACTERS FOR IO-ERROR
-
-
 main {
 
     const ubyte numforLave = 7      ;  Lave is 7th generated planet in galaxy one

examples/turtle-gfx.p8

@@ -4,6 +4,8 @@
 %import test_stack
 %zeropage floatsafe
 
+; TODO WHY is this a couple of 100 bytes larger than a few hours ago?
+
 main {
 
     sub start() {