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/***************************************************************************
* __________ __ ___.
* 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 found in Linux kernel version 2.6.15.3
* linux/arch/arm/lib/memset.S
*
* Copyright (C) 1995-2000 Russell King
*/
/* This code will align a pointer for memset, if needed */
1: cmp r2, #4 @ 1 do we have enough
blt 5f @ 1 bytes to align with?
cmp r3, #2 @ 1
strgtb r1, [r0, #-1]! @ 1
strgeb r1, [r0, #-1]! @ 1
strb r1, [r0, #-1]! @ 1
sub r2, r2, r3 @ 1 r2 = r2 - r3
b 2f
.global memset
.type memset,%function
memset:
add r0, r0, r2 @ we'll write backwards in memory
ands r3, r0, #3 @ 1 unaligned?
bne 1b @ 1
2:
/*
* we know that the pointer in r0 is aligned to a word boundary.
*/
orr r1, r1, r1, lsl #8
orr r1, r1, r1, lsl #16
mov r3, r1
cmp r2, #16
blt 5f
/*
* 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
3: subs r2, r2, #64
stmgedb r0!, {r1, r3, ip, lr} @ 64 bytes at a time.
stmgedb r0!, {r1, r3, ip, lr}
stmgedb r0!, {r1, r3, ip, lr}
stmgedb r0!, {r1, r3, ip, lr}
bgt 3b
ldrpc cond=eq @ Now <64 bytes to go.
/*
* No need to correct the count; we're only testing bits from now on
*/
tst r2, #32
stmnedb r0!, {r1, r3, ip, lr}
stmnedb r0!, {r1, r3, ip, lr}
tst r2, #16
stmnedb r0!, {r1, r3, ip, lr}
ldr lr, [sp], #4
5: tst r2, #8
stmnedb r0!, {r1, r3}
tst r2, #4
strne r1, [r0, #-4]!
/*
* When we get here, we've got less than 4 bytes to zero. We
* may have an unaligned pointer as well.
*/
6: tst r2, #2
strneb r1, [r0, #-1]!
strneb r1, [r0, #-1]!
tst r2, #1
strneb r1, [r0, #-1]!
bx lr
.end:
.size memset,.end-memset
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