cc65/libsrc/common/strpbrk.s

54 lines
1.5 KiB
ArmAsm

;
; 1998-06-11, Ullrich von Bassewitz
; 2018-05-29, Greg King
;
; char* __fastcall__ strpbrk (const char* str, const char* set);
;
.export _strpbrk
.import popax
.importzp ptr1, ptr2, tmp2, tmp3
_strpbrk:
sta ptr2 ; store set
stx ptr2+1
jsr popax
stx ptr1+1 ; store str's high byte
ldx #<$0000
stx ptr1
tay ; use str's low byte as index
L1: lda (ptr1),y ; get next char from str
beq L9 ; jump if done
sta tmp2 ; save char
sty tmp3 ; save index into str
ldy #$00
L3: lda (ptr2),y ; look at each char in set
beq L4 ; jump if done
cmp tmp2
beq L6 ; break out of loops if something found
iny
bne L3
; The character was not found in set. Increment the counter; and start over.
L4: ldy tmp3 ; reload index
iny
bne L1
inc ptr1+1
bne L1 ; branch always
; A character was found. Return its str pointer.
L6: ldx ptr1+1
lda tmp3 ; get .Y offset
rts
; None of the characters in set was found -- return NULL.
L9: ;ldx #>$0000 ; (set by prolog)
;lda #<$0000 ; (set by '\0' at end of str)
rts