mirror of
https://github.com/cc65/cc65.git
synced 2024-12-23 04:30:10 +00:00
42 lines
1.1 KiB
ArmAsm
42 lines
1.1 KiB
ArmAsm
;
|
|
; Ullrich von Bassewitz, 31.05.1998
|
|
; Christian Krueger: 2013-Aug-01, optimization
|
|
;
|
|
; char* strrchr (const char* s, int c);
|
|
;
|
|
|
|
.export _strrchr
|
|
.import popax
|
|
.importzp ptr1, tmp1, tmp2
|
|
|
|
_strrchr:
|
|
sta tmp1 ; Save c
|
|
jsr popax ; get s
|
|
tay ; low byte to y
|
|
stx ptr1+1
|
|
ldx #0 ; default function result is NULL, X is high byte...
|
|
stx tmp2 ; tmp2 is low-byte
|
|
stx ptr1 ; low-byte of source string is in Y, so clear real one...
|
|
|
|
testChar:
|
|
lda (ptr1),y ; get char
|
|
beq finished ; jump if end of string
|
|
cmp tmp1 ; found?
|
|
bne nextChar ; jump if no
|
|
|
|
charFound:
|
|
sty tmp2 ; y has low byte of location, save it
|
|
ldx ptr1+1 ; x holds high-byte of result
|
|
|
|
nextChar:
|
|
iny
|
|
bne testChar
|
|
inc ptr1+1
|
|
bne testChar ; here like bra...
|
|
|
|
; return the pointer to the last occurrence
|
|
|
|
finished:
|
|
lda tmp2 ; high byte in X is already correct...
|
|
rts
|