You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
54 lines
861 B
ArmAsm
54 lines
861 B
ArmAsm
;
|
|
; Ullrich von Bassewitz, 07.04.2000
|
|
;
|
|
; CC65 runtime: += operator
|
|
;
|
|
; On entry, the low byte of the address of the variable to increment is
|
|
; in ptr1, the high byte is in Y, and the increment is in eax.
|
|
;
|
|
|
|
.export laddeq1, laddeqa, laddeq
|
|
.importzp sreg, ptr1, tmp1
|
|
|
|
|
|
laddeq1:
|
|
lda #$01
|
|
|
|
laddeqa:
|
|
ldx #$00
|
|
stx sreg
|
|
stx sreg+1
|
|
|
|
laddeq: sty ptr1+1 ; Store high byte of address
|
|
ldy #$00 ; Address low byte
|
|
clc
|
|
|
|
adc (ptr1),y
|
|
sta (ptr1),y
|
|
pha ; Save byte 0 of result for later
|
|
|
|
iny ; Address byte 1
|
|
txa
|
|
adc (ptr1),y ; Load byte 1
|
|
sta (ptr1),y
|
|
tax
|
|
|
|
iny ; Address byte 2
|
|
lda sreg
|
|
adc (ptr1),y
|
|
sta (ptr1),y
|
|
sta sreg
|
|
|
|
iny ; Address byte 3
|
|
lda sreg+1
|
|
adc (ptr1),y
|
|
sta (ptr1),y
|
|
sta sreg+1
|
|
|
|
pla ; Retrieve byte 0 of result
|
|
|
|
rts ; Done
|
|
|
|
|
|
|