xref: /openbmc/linux/arch/arm64/lib/strchr.S (revision 588b48ca)
1/*
2 * Based on arch/arm/lib/strchr.S
3 *
4 * Copyright (C) 1995-2000 Russell King
5 * Copyright (C) 2013 ARM Ltd.
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
18 */
19
20#include <linux/linkage.h>
21#include <asm/assembler.h>
22
23/*
24 * Find the first occurrence of a character in a string.
25 *
26 * Parameters:
27 *	x0 - str
28 *	x1 - c
29 * Returns:
30 *	x0 - address of first occurrence of 'c' or 0
31 */
32ENTRY(strchr)
33	and	w1, w1, #0xff
341:	ldrb	w2, [x0], #1
35	cmp	w2, w1
36	ccmp	w2, wzr, #4, ne
37	b.ne	1b
38	sub	x0, x0, #1
39	cmp	w2, w1
40	csel	x0, x0, xzr, eq
41	ret
42ENDPROC(strchr)
43