cc65/libsrc/rp6502/xreg.s

38 lines
577 B
ArmAsm

;
; 2023, Rumbledethumps
;
; CC65 will promote variadic char arguments to int. It will not demote longs.
; int __cdecl__ xreg(char device, char channel, unsigned char address, ...);
.export _xreg
.importzp sp
.import addysp, _ria_call_int_errno
.include "rp6502.inc"
.code
.proc _xreg
; save variadic size in X
tya
tax
@copy: ; copy stack
dey
lda (sp),y
sta RIA_XSTACK
tya
bne @copy
; recover variadic size and move sp
txa
tay
jsr addysp
; run RIA operation
lda #RIA_OP_XREG
jmp _ria_call_int_errno
.endproc