xref: /linux/arch/arm64/lib/memchr.S (revision 4a8992271c843cb5bcd3321bf6a02eb251280b1d)
1*4a899227SCatalin Marinas/*
2*4a899227SCatalin Marinas * Based on arch/arm/lib/memchr.S
3*4a899227SCatalin Marinas *
4*4a899227SCatalin Marinas * Copyright (C) 1995-2000 Russell King
5*4a899227SCatalin Marinas * Copyright (C) 2013 ARM Ltd.
6*4a899227SCatalin Marinas *
7*4a899227SCatalin Marinas * This program is free software; you can redistribute it and/or modify
8*4a899227SCatalin Marinas * it under the terms of the GNU General Public License version 2 as
9*4a899227SCatalin Marinas * published by the Free Software Foundation.
10*4a899227SCatalin Marinas *
11*4a899227SCatalin Marinas * This program is distributed in the hope that it will be useful,
12*4a899227SCatalin Marinas * but WITHOUT ANY WARRANTY; without even the implied warranty of
13*4a899227SCatalin Marinas * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14*4a899227SCatalin Marinas * GNU General Public License for more details.
15*4a899227SCatalin Marinas *
16*4a899227SCatalin Marinas * You should have received a copy of the GNU General Public License
17*4a899227SCatalin Marinas * along with this program.  If not, see <http://www.gnu.org/licenses/>.
18*4a899227SCatalin Marinas */
19*4a899227SCatalin Marinas
20*4a899227SCatalin Marinas#include <linux/linkage.h>
21*4a899227SCatalin Marinas#include <asm/assembler.h>
22*4a899227SCatalin Marinas
23*4a899227SCatalin Marinas/*
24*4a899227SCatalin Marinas * Find a character in an area of memory.
25*4a899227SCatalin Marinas *
26*4a899227SCatalin Marinas * Parameters:
27*4a899227SCatalin Marinas *	x0 - buf
28*4a899227SCatalin Marinas *	x1 - c
29*4a899227SCatalin Marinas *	x2 - n
30*4a899227SCatalin Marinas * Returns:
31*4a899227SCatalin Marinas *	x0 - address of first occurrence of 'c' or 0
32*4a899227SCatalin Marinas */
33*4a899227SCatalin MarinasENTRY(memchr)
34*4a899227SCatalin Marinas	and	w1, w1, #0xff
35*4a899227SCatalin Marinas1:	subs	x2, x2, #1
36*4a899227SCatalin Marinas	b.mi	2f
37*4a899227SCatalin Marinas	ldrb	w3, [x0], #1
38*4a899227SCatalin Marinas	cmp	w3, w1
39*4a899227SCatalin Marinas	b.ne	1b
40*4a899227SCatalin Marinas	sub	x0, x0, #1
41*4a899227SCatalin Marinas	ret
42*4a899227SCatalin Marinas2:	mov	x0, #0
43*4a899227SCatalin Marinas	ret
44*4a899227SCatalin MarinasENDPROC(memchr)
45