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cc65/libsrc/common/strpbrk.s

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;
; Ullrich von Bassewitz, 11.06.1998
;
; char* strpbrk (const char* s1, const char* s2);
;
.export _strpbrk
.import popax, return0
.importzp ptr1, ptr2, tmp1, tmp2, tmp3
_strpbrk:
jsr popax ; get s2
sta ptr2
stx ptr2+1
jsr popax ; get s1
sta ptr1
stx ptr1+1
ldy #$00
L1: lda (ptr1),y ; get next char from s1
beq L9 ; jump if done
sta tmp2 ; save char
iny
bne L2
inc ptr1+1
L2: sty tmp3 ; save index into s1
ldy #0 ; get index into s2
L3: lda (ptr2),y ;
beq L4 ; jump if done
cmp tmp2
beq L6
iny
bne L3
; The character was not found in s2. Increment the counter and start over
L4: ldy tmp3 ; reload index
inx
bne L1
inc tmp1
bne L1
; A character was found. Calculate a pointer to this char in s1 and return it.
L6: ldx ptr1+1
lda tmp3 ; get y offset
clc
adc ptr1
bcc L7
inx
L7: rts
; None of the characters in s2 was found - return NULL
L9: jmp return0