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;
; Ullrich von Bassewitz, 07.04.2000
; Christian Krueger, 12-Mar-2017, added 65SC02 optimization
;
; 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
.macpack cpu
laddeq1:
lda #$01
laddeqa:
ldx #$00
stx sreg
stx sreg+1
laddeq: sty ptr1+1 ; Store high byte of address
clc
.if (.cpu .bitand ::CPU_ISET_65SC02)
adc (ptr1)
sta (ptr1)
ldy #$01 ; Address byte 1
.else
ldy #$00 ; Address low byte
adc (ptr1),y
sta (ptr1),y
iny ; Address byte 1
.endif
pha ; Save byte 0 of result for later
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
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