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cc65/libsrc/runtime/lrsub.s

39 lines
795 B
ArmAsm

;
; Ullrich von Bassewitz, 05.08.1998
;
; CC65 runtime: long sub reversed
;
;
; EAX = EAX - TOS
;
.export tosrsub0ax, tosrsubeax
.import addysp1
.importzp sp, sreg, tmp1
tosrsub0ax:
ldy #$00
sty sreg
sty sreg+1
tosrsubeax:
ldy #0
sec
sbc (sp),y ; byte 0
sta tmp1 ; use as temp storage
txa
iny
sbc (sp),y ; byte 1
tax
iny
lda sreg
sbc (sp),y ; byte 2
sta sreg
iny
lda sreg+1
sbc (sp),y ; byte 3
sta sreg+1
lda tmp1
jmp addysp1 ; drop TOS