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37 lines
464 B
ArmAsm

;
; Ullrich von Bassewitz, 08.10.1998
;
; CC65 runtime: -= operator for longs on the stack
;
.export lsubeq0sp, lsubeqysp
.importzp sp, sreg
lsubeq0sp:
ldy #0
lsubeqysp:
sec
eor #$FF
adc (sp),y
sta (sp),y
pha ; Save low byte
iny
txa
eor #$FF
adc (sp),y
sta (sp),y
tax
iny
lda (sp),y
sbc sreg
sta (sp),y
sta sreg
iny
lda (sp),y
sbc sreg+1
sta (sp),y
sta sreg+1
pla
rts