strlen.S revision 150875 
1/*-
2 * Copyright (c) 2005 Olivier Houchard
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright             *    notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 *    notice, this list of conditions and the following disclaimer in the
11 *    documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
14 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
17 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
23 * SUCH DAMAGE.
24 */
25
26#include <machine/asm.h>
27__FBSDID("$FreeBSD: head/lib/libc/arm/string/strlen.S 150875 2005-10-03 14:21:49Z cognet $");
28
29ENTRY(strlen)
30	mov	r1, #0
31	/* Check that the pointer is aligned on 32 bits. */
32	ands	r3, r0, #3
33	beq	.Loop
34	sub	r0, r0, r3
35	ldr	r2, [r0]
36	add	r0, r0, #4
37	cmp	r3, #2
38	blt	.Ldo_3
39	bgt	.Ldo_1
40	/* So that the N bit is set. */
41	cmp	r3, #0
42	b	.Ldo_2
43
44.Loop:
45	ldr	r2, [r0]
46	add	r0, r0, #4
47#ifndef __ARMEB__
48	ands	r3, r2, #0x000000ff
49#else
50	ands	r3, r2, #0xff000000
51#endif
52	addne	r1, r1, #1
53.Ldo_3:
54#ifndef __ARMEB__
55	andnes    r3, r2, #0x0000ff00
56#else
57  	andnes    r3, r2, #0x00ff0000
58#endif
59	addne     r1, r1, #1
60.Ldo_2:
61#ifndef __ARMEB__
62	andnes    r3, r2, #0x00ff0000
63#else
64	andnes    r3, r2, #0x0000ff00
65#endif
66	addne	r1, r1, #1
67.Ldo_1:
68#ifndef __ARMEB__
69	andnes	r3, r2, #0xff000000
70#else
71	andnes	r3, r2, #0x000000ff
72#endif
73	addne	r1, r1, #1
74	bne	.Loop
75.Lexit:
76	mov	r0, r1
77	RET
78