rockbox/firmware/target/arm/memset16-arm.S
Daniel Stenberg 2acc0ac542 Updated our source code header to explicitly mention that we are GPL v2 or
later. We still need to hunt down snippets used that are not. 1324 modified
files...
http://www.rockbox.org/mail/archive/rockbox-dev-archive-2008-06/0060.shtml


git-svn-id: svn://svn.rockbox.org/rockbox/trunk@17847 a1c6a512-1295-4272-9138-f99709370657
2008-06-28 18:10:04 +00:00

82 lines
2.5 KiB
ArmAsm

/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2006 by Thom Johansen
*
* 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.
*
****************************************************************************/
#include "config.h"
.section .icode,"ax",%progbits
.align 2
/* The following code is based on code from the Linux kernel version 2.6.15.3,
* linux/arch/arm/lib/memset.S
*
* Copyright (C) 1995-2000 Russell King
*/
.global memset16
.type memset16,%function
memset16:
tst r0, #2 @ unaligned?
cmpne r2, #0
strneh r1, [r0], #2 @ store one halfword to align
subne r2, r2, #1
/*
* we know that the pointer in r0 is aligned to a word boundary.
*/
orr r1, r1, r1, lsl #16
mov r3, r1
cmp r2, #8
blt 4f
/*
* We need an extra register for this loop - save the return address and
* use the LR
*/
str lr, [sp, #-4]!
mov ip, r1
mov lr, r1
2: subs r2, r2, #32
stmgeia r0!, {r1, r3, ip, lr} @ 64 bytes at a time.
stmgeia r0!, {r1, r3, ip, lr}
stmgeia r0!, {r1, r3, ip, lr}
stmgeia r0!, {r1, r3, ip, lr}
bgt 2b
ldmeqfd sp!, {pc} @ Now <64 bytes to go.
/*
* No need to correct the count; we're only testing bits from now on
*/
tst r2, #16
stmneia r0!, {r1, r3, ip, lr}
stmneia r0!, {r1, r3, ip, lr}
tst r2, #8
stmneia r0!, {r1, r3, ip, lr}
ldr lr, [sp], #4
4: tst r2, #4
stmneia r0!, {r1, r3}
tst r2, #2
strne r1, [r0], #4
tst r2, #1
strneh r1, [r0], #2
bx lr
.end:
.size memset16,.end-memset16