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/*
strstr.S
Search string contained in a string
Contributors:
Created by Jochen Pernsteiner <jochen.pernsteiner@stud.fh-regensburg.de>
THIS SOFTWARE IS NOT COPYRIGHTED
This source code is offered for use in the public domain. You may
use, modify or distribute it freely.
This code is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY. ALL WARRANTIES, EXPRESS OR IMPLIED ARE HEREBY
DISCLAIMED. This includes but is not limited to warranties of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
*/
#include "macros.inc"
#define s1_hi r25
#define s1_lo r24
#define s2_hi r23
#define s2_lo r22
#define tmp r21
#define ret_hi r25
#define ret_lo r24
;char *strstr(const char *s1, const char *s2)
.text
.global _U(strstr)
.type _U(strstr), @function
_U(strstr):
LOAD_X(s1_lo, s1_hi)
LOAD_Z(s2_lo, s2_hi)
ld tmp, Z+
tst tmp
breq .strstr_ret
clr ret_lo
clr ret_hi
.strstr_loop:
ld __tmp_reg__, X+
tst __tmp_reg__
breq .strstr_ret0
cp __tmp_reg__, tmp
brne .strstr_loop
adiw ret_lo, 1
ld tmp, Z+
tst tmp
brne .strstr_loop
sub XL, ret_lo
sbc XH, ret_hi
mov ret_lo, XL
mov ret_hi, XH
ret
.strstr_ret0:
clr ret_lo
clr ret_hi
.strstr_ret:
ret
.strstr_end:
.size _U(strstr), .strstr_end - _U(strstr)
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