blob: 8c65760ce6c23621789231705a0b1a6db6779e3c [file] [log] [blame]
/*
* Copyright (c) 2020, Arm Limited. All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
#include <asm_macros.S>
.global memset
/* -----------------------------------------------------------------------
* void memset(void *dst, int val, size_t count)
*
* Copy the value of 'val' (converted to an unsigned char) into
* each of the first 'count' characters of the object pointed to by 'dst'.
*
* Returns the value of 'dst'.
* -----------------------------------------------------------------------
*/
func memset
cbz w2, exit /* exit if 'count' = 0 */
mov x3, x0 /* keep x0 */
tst x0, #7
b.eq aligned /* 8-bytes aligned */
/* Unaligned 'dst' */
unaligned:
strb w1, [x3], #1
subs w2, w2, #1
b.eq exit /* exit if 0 */
tst x3, #7
b.ne unaligned /* continue while unaligned */
/* 8-bytes aligned */
aligned:cbz x1, x1_zero
bfi w1, w1, #8, #8 /* propagate 'val' */
bfi w1, w1, #16, #16
bfi x1, x1, #32, #32
x1_zero:ands w4, w2, #~0x3f
b.eq less_64
write_64:
.rept 4
stp x1, x1, [x3], #16 /* write 64 bytes in a loop */
.endr
subs w4, w4, #64
b.ne write_64
ands w2, w2, #0x3f
b.eq exit /* exit if 0 */
less_64:tbz w2, #5, less_32 /* < 32 bytes */
stp x1, x1, [x3], #16 /* write 32 bytes */
stp x1, x1, [x3], #16
ands w2, w2, #0x1f
b.eq exit
less_32:tbz w2, #4, less_16 /* < 16 bytes */
stp x1, x1, [x3], #16 /* write 16 bytes */
ands w2, w2, #0xf
b.eq exit
less_16:tbz w2, #3, less_8 /* < 8 bytes */
str x1, [x3], #8 /* write 8 bytes */
ands w2, w2, #7
b.eq exit
less_8: tbz w2, #2, less_4 /* < 4 bytes */
str w1, [x3], #4 /* write 4 bytes */
ands w2, w2, #3
b.eq exit
less_4: tbz w2, #1, less_2 /* < 2 bytes */
strh w1, [x3], #2 /* write 2 bytes */
tbz w2, #0, exit
less_2: strb w1, [x3] /* write 1 byte */
exit: ret
endfunc memset