xref: /freebsd/lib/libc/arm/string/strlen.S (revision 3507a1571359e36fafd825c6a5e7574e50a58702)
13507a157SOlivier Houchard/*-
23507a157SOlivier Houchard * Copyright (c) 2005 Olivier Houchard
33507a157SOlivier Houchard * All rights reserved.
43507a157SOlivier Houchard *
53507a157SOlivier Houchard * Redistribution and use in source and binary forms, with or without
63507a157SOlivier Houchard * modification, are permitted provided that the following conditions
73507a157SOlivier Houchard * are met:
83507a157SOlivier Houchard * 1. Redistributions of source code must retain the above copyright             *    notice, this list of conditions and the following disclaimer.
93507a157SOlivier Houchard * 2. Redistributions in binary form must reproduce the above copyright
103507a157SOlivier Houchard *    notice, this list of conditions and the following disclaimer in the
113507a157SOlivier Houchard *    documentation and/or other materials provided with the distribution.
123507a157SOlivier Houchard *
133507a157SOlivier Houchard * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
143507a157SOlivier Houchard * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
153507a157SOlivier Houchard * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
163507a157SOlivier Houchard * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
173507a157SOlivier Houchard * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
183507a157SOlivier Houchard * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
193507a157SOlivier Houchard * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
203507a157SOlivier Houchard * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
213507a157SOlivier Houchard * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
223507a157SOlivier Houchard * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
233507a157SOlivier Houchard * SUCH DAMAGE.
243507a157SOlivier Houchard */
253507a157SOlivier Houchard
263507a157SOlivier Houchard#include <machine/asm.h>
273507a157SOlivier Houchard__FBSDID("$FreeBSD$");
283507a157SOlivier Houchard
293507a157SOlivier HouchardENTRY(strlen)
303507a157SOlivier Houchard	mov	r1, #0
313507a157SOlivier Houchard	/* Check that the pointer is aligned on 32 bits. */
323507a157SOlivier Houchard	ands	r3, r0, #3
333507a157SOlivier Houchard	beq	.Loop
343507a157SOlivier Houchard	sub	r0, r0, r3
353507a157SOlivier Houchard	ldr	r2, [r0]
363507a157SOlivier Houchard	add	r0, r0, #4
373507a157SOlivier Houchard	cmp	r3, #2
383507a157SOlivier Houchard	blt	.Ldo_3
393507a157SOlivier Houchard	bgt	.Ldo_1
403507a157SOlivier Houchard	/* So that the N bit is set. */
413507a157SOlivier Houchard	cmp	r3, #0
423507a157SOlivier Houchard	b	.Ldo_2
433507a157SOlivier Houchard
443507a157SOlivier Houchard.Loop:
453507a157SOlivier Houchard	ldr	r2, [r0]
463507a157SOlivier Houchard	add	r0, r0, #4
473507a157SOlivier Houchard#ifndef __ARMEB__
483507a157SOlivier Houchard	ands	r3, r2, #0x000000ff
493507a157SOlivier Houchard#else
503507a157SOlivier Houchard	ands	r3, r2, #0xff000000
513507a157SOlivier Houchard#endif
523507a157SOlivier Houchard	addne	r1, r1, #1
533507a157SOlivier Houchard.Ldo_3:
543507a157SOlivier Houchard#ifndef __ARMEB__
553507a157SOlivier Houchard	andnes    r3, r2, #0x0000ff00
563507a157SOlivier Houchard#else
573507a157SOlivier Houchard  	andnes    r3, r2, #0x00ff0000
583507a157SOlivier Houchard#endif
593507a157SOlivier Houchard	addne     r1, r1, #1
603507a157SOlivier Houchard.Ldo_2:
613507a157SOlivier Houchard#ifndef __ARMEB__
623507a157SOlivier Houchard	andnes    r3, r2, #0x00ff0000
633507a157SOlivier Houchard#else
643507a157SOlivier Houchard	andnes    r3, r2, #0x0000ff00
653507a157SOlivier Houchard#endif
663507a157SOlivier Houchard	addne	r1, r1, #1
673507a157SOlivier Houchard.Ldo_1:
683507a157SOlivier Houchard#ifndef __ARMEB__
693507a157SOlivier Houchard	andnes	r3, r2, #0xff000000
703507a157SOlivier Houchard#else
713507a157SOlivier Houchard	andnes	r3, r2, #0x000000ff
723507a157SOlivier Houchard#endif
733507a157SOlivier Houchard	addne	r1, r1, #1
743507a157SOlivier Houchard	bne	.Loop
753507a157SOlivier Houchard.Lexit:
763507a157SOlivier Houchard	mov	r0, r1
773507a157SOlivier Houchard	RET
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