mirror of
https://github.com/cc65/cc65.git
synced 2024-07-03 22:29:31 +00:00
42 lines
728 B
ArmAsm
42 lines
728 B
ArmAsm
|
;
|
||
|
|
; Ullrich von Bassewitz, 31.05.1998
|
||
|
|
;
|
||
|
|
; const char* strchr (const char* s, int c);
|
||
|
|
;
|
||
|
|
|
||
|
|
.export _strchr
|
||
|
|
.import popax
|
||
|
|
.importzp ptr1, tmp1
|
||
|
|
|
||
|
|
_strchr:
|
||
|
|
sta tmp1 ; Save c
|
||
|
|
jsr popax ; get s
|
||
|
|
sta ptr1
|
||
|
|
stx ptr1+1
|
||
|
|
ldy #0
|
||
|
|
|
||
|
|
scloop: lda (ptr1),y ; get next char
|
||
|
|
beq strz ; jump if end of string
|
||
|
|
cmp tmp1 ; found?
|
||
|
|
beq strf ; jump if yes
|
||
|
|
iny
|
||
|
|
bne scloop
|
||
|
|
inc ptr1+1
|
||
|
|
bne scloop ; jump always
|
||
|
|
|
||
|
|
; found, calculate pointer to c
|
||
|
|
|
||
|
|
strf: ldx ptr1+1 ; get high byte of pointer
|
||
|
|
tya ; low byte offset
|
||
|
|
clc
|
||
|
|
adc ptr1
|
||
|
|
bcc str1
|
||
|
|
inx
|
||
|
|
str1: rts
|
||
|
|
|
||
|
|
; not found, return zero
|
||
|
|
|
||
|
|
strz: tax ; return 0
|
||
|
|
rts
|
||
|
|
|