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/* Copyright (c) 2010-2011, Linaro Limited
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
* Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
* Neither the name of Linaro Limited nor the names of its
contributors may be used to endorse or promote products derived
from this software without specific prior written permission.
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,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/*
Written by Dave Gilbert <david.gilbert@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.
*/
@ 2011-02-07 david.gilbert@linaro.org
@ Extracted from local git a5b438d861
.syntax unified
.arch armv7-a
.text
.thumb
@ ---------------------------------------------------------------------------
.thumb_func
.align 2
.p2align 4,,15
.global strchr
.type strchr,%function
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
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