xref: /freebsd/lib/libc/arm/string/strlen.S (revision 1d386b48a555f61cb7325543adbbb5c3f3407a66)
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:
8dc9e655cSOlivier Houchard * 1. Redistributions of source code must retain the above copyright
9dc9e655cSOlivier Houchard *    notice, this list of conditions and the following disclaimer.
103507a157SOlivier Houchard * 2. Redistributions in binary form must reproduce the above copyright
113507a157SOlivier Houchard *    notice, this list of conditions and the following disclaimer in the
123507a157SOlivier Houchard *    documentation and/or other materials provided with the distribution.
133507a157SOlivier Houchard *
143507a157SOlivier Houchard * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
153507a157SOlivier Houchard * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
163507a157SOlivier Houchard * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
173507a157SOlivier Houchard * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
183507a157SOlivier Houchard * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
193507a157SOlivier Houchard * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
203507a157SOlivier Houchard * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
213507a157SOlivier Houchard * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
223507a157SOlivier Houchard * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
233507a157SOlivier Houchard * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
243507a157SOlivier Houchard * SUCH DAMAGE.
253507a157SOlivier Houchard */
263507a157SOlivier Houchard
273507a157SOlivier Houchard#include <machine/asm.h>
28a215cdfdSAndrew Turner.syntax	unified
29a215cdfdSAndrew Turner
303507a157SOlivier HouchardENTRY(strlen)
313507a157SOlivier Houchard	mov	r1, #0
323507a157SOlivier Houchard	/* Check that the pointer is aligned on 32 bits. */
333507a157SOlivier Houchard	ands	r3, r0, #3
343507a157SOlivier Houchard	beq	.Loop
353507a157SOlivier Houchard	sub	r0, r0, r3
363507a157SOlivier Houchard	ldr	r2, [r0]
373507a157SOlivier Houchard	add	r0, r0, #4
383507a157SOlivier Houchard	cmp	r3, #2
393507a157SOlivier Houchard	blt	.Ldo_3
403507a157SOlivier Houchard	bgt	.Ldo_1
413507a157SOlivier Houchard	/* So that the N bit is set. */
423507a157SOlivier Houchard	cmp	r3, #0
433507a157SOlivier Houchard	b	.Ldo_2
443507a157SOlivier Houchard
453507a157SOlivier Houchard.Loop:
463507a157SOlivier Houchard	ldr	r2, [r0]
473507a157SOlivier Houchard	add	r0, r0, #4
483507a157SOlivier Houchard	ands	r3, r2, #0x000000ff
496c5bc49cSAndrew Turner	it	ne
503507a157SOlivier Houchard	addne	r1, r1, #1
513507a157SOlivier Houchard.Ldo_3:
526c5bc49cSAndrew Turner	itt	ne
53a215cdfdSAndrew Turner	andsne    r3, r2, #0x0000ff00
543507a157SOlivier Houchard	addne     r1, r1, #1
553507a157SOlivier Houchard.Ldo_2:
566c5bc49cSAndrew Turner	itt	ne
57a215cdfdSAndrew Turner	andsne    r3, r2, #0x00ff0000
583507a157SOlivier Houchard	addne	r1, r1, #1
593507a157SOlivier Houchard.Ldo_1:
606c5bc49cSAndrew Turner	ittt	ne
61a215cdfdSAndrew Turner	andsne	r3, r2, #0xff000000
623507a157SOlivier Houchard	addne	r1, r1, #1
633507a157SOlivier Houchard	bne	.Loop
643507a157SOlivier Houchard.Lexit:
653507a157SOlivier Houchard	mov	r0, r1
663507a157SOlivier Houchard	RET
67f2e71517SIan LeporeEND(strlen)
68*96cdb0abSKonstantin Belousov
69*96cdb0abSKonstantin Belousov	.section .note.GNU-stack,"",%progbits
70