fix possible register corruption when calling asmsubs that require Carry flag as a parameter

2024-12-24 01:29:28 +00:00 · 2023-09-24 14:03:31 +02:00 · 2023-09-24 14:03:31 +02:00 · 8d177beb78
commit 8d177beb78
parent 1da0c59182
1 changed files with 3 additions and 2 deletions
--- a/codeGenCpu6502/src/prog8/codegen/cpu6502/FunctionCallAsmGen.kt
+++ b/codeGenCpu6502/src/prog8/codegen/cpu6502/FunctionCallAsmGen.kt
@ -141,13 +141,14 @@ internal class FunctionCallAsmGen(private val program: PtProgram, private val as
                    }
                    is PtIdentifier -> {
                        val sourceName = asmgen.asmVariableName(value)
+                        // note: cannot use X register here to store A because it might be used for other arguments
                        asmgen.out("""
-                            tax
+                            pha
                            clc
                            lda  $sourceName
                            beq  +
                            sec  
-+                           txa""")
+                           pla""")
                    }
                    else -> {
                        asmgen.assignExpressionToRegister(value, RegisterOrPair.A)