rockbox/firmware/target/coldfire/strlen-coldfire.S

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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id $
*
* Copyright (C) 2007 Nils Wallménius
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
/* size_t strlen(const char *str) */
.section .text,"ax",@progbits
.align 2
.globl strlen
.type strlen, @function
strlen:
move.l 4(%sp),%a0 /* %a0 = *str */
move.l %a0,%d0 /* %d0 = start address */
1:
tst.b (%a0)+ /* test if %a0 == 0 and increment */
bne.b 1b /* if the test was false repeat */
sub.l %d0,%a0 /* how many times did we repeat? */
move.l %a0,%d0
subq.l #1,%d0 /* %d0 is 1 too large due to the last increment */
rts
.size strlen, .-strlen