/* Copyright (c) 2010-2011, Linaro Limited
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      * Neither the name of Linaro Limited nor the names of its
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   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
   HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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   Written by Dave Gilbert <david.gilbert@linaro.org>
   Adapted to Bionic by Bernhard Rosenkraenzer <Bernhard.Rosenkranzer@linaro.org>

   A very simple strchr routine, from benchmarks on A9 it's a bit faster than
   the current version in eglibc (2.12.1-0ubuntu14 package)
   I don't think doing a word at a time version is worth it since a lot
    of strchr cases are very short anyway */

#include <machine/asm.h>

@ 2011-02-07 david.gilbert@linaro.org
@    Extracted from local git a5b438d861

	.syntax unified
	.arch armv7-a

	.text
	.thumb

@ ---------------------------------------------------------------------------

	.thumb_func
	.p2align 4,,15
ENTRY(strchr)
	@ r0 = start of string
	@ r1 = character to match
	@ returns NULL for no match, or a pointer to the match
	and	r1,r1, #255

1:
	ldrb	r2,[r0],#1
	cmp	r2,r1
	cbz	r2,10f
	bne	1b

	@ We're here if it matched
5:
	subs	r0,r0,#1
	bx	lr

10:
	@ We're here if we ran off the end
	cmp	r1, #0	@ Corner case - you're allowed to search for the nil and get a pointer to it
	beq	5b	@ A bit messy, if it's common we should branch at the start to a special loop
	mov	r0,#0
	bx	lr
END(strchr)
