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; replacement for atoi() that doesn't use cc65's bloated ctype.
; also, doesn't handle signed results (not needed).
.export _a2uint
.import _isnum
.importzp ptr1, sreg
result = sreg
temp16 = sreg+2
_a2uint:
sta ptr1
stx ptr1+1
lda #0
sta result
sta result+1
tay
@chrloop:
lda (ptr1),y ; get next character
jsr _isnum ; is is a digit?
beq @done ; Z set = non-digit
; multiply result by 10
; {
lda result
asl
sta temp16
lda result+1
rol
sta temp16+1 ; temp16 now result * 2
ldx #3
@x8loop:
asl result
rol result+1
dex
bne @x8loop
; result now result * 8
clc
lda result
adc temp16
sta result
lda result+1
adc temp16+1
sta result+1 ; result now original result * 10
; }
lda (ptr1),y ; get character again
iny ; point to next char
and #$0f ; de-ASCIIfy
clc
adc result
sta result
bcc @chrloop
inc result+1
bne @chrloop
@done:
lda result
ldx result+1
rts
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