linux/arch/arm64/lib/memset.S
Catalin Marinas 4a8992271c arm64: klib: Optimised memory functions
This patch introduces AArch64-specific memory functions (memcpy,
memmove, memchr, memset). These functions are not optimised for any CPU
implementation but can be used as a starting point once hardware is
available.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2013-03-21 17:39:29 +00:00

54 lines
1.2 KiB
ArmAsm

/*
* Copyright (C) 2013 ARM Ltd.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <linux/linkage.h>
#include <asm/assembler.h>
/*
* Fill in the buffer with character c (alignment handled by the hardware)
*
* Parameters:
* x0 - buf
* x1 - c
* x2 - n
* Returns:
* x0 - buf
*/
ENTRY(memset)
mov x4, x0
and w1, w1, #0xff
orr w1, w1, w1, lsl #8
orr w1, w1, w1, lsl #16
orr x1, x1, x1, lsl #32
subs x2, x2, #8
b.mi 2f
1: str x1, [x4], #8
subs x2, x2, #8
b.pl 1b
2: adds x2, x2, #4
b.mi 3f
sub x2, x2, #4
str w1, [x4], #4
3: adds x2, x2, #2
b.mi 4f
sub x2, x2, #2
strh w1, [x4], #2
4: adds x2, x2, #1
b.mi 5f
strb w1, [x4]
5: ret
ENDPROC(memset)