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// SPDX-License-Identifier: GPL-2.0
// Copyright (C) 2005-2017 Andes Technology Corporation
#include <linux/linkage.h>
.text
ENTRY(memset)
move $r5, $r0 ! Return value
beqz $r2, end_memset ! Exit when len = 0
srli $p1, $r2, 2 ! $p1 is how many words to copy
andi $r2, $r2, 3 ! How many bytes are less than a word
beqz $p1, byte_set ! When n is less than a word
! set $r1 from ??????ab to abababab
andi $r1, $r1, #0x00ff ! $r1 = 000000ab
slli $p0, $r1, #8 ! $p0 = 0000ab00
or $r1, $r1, $p0 ! $r1 = 0000abab
slli $p0, $r1, #16 ! $p0 = abab0000
or $r1, $r1, $p0 ! $r1 = abababab
word_set:
addi $p1, $p1, #-1 ! How many words left to copy
smw.bim $r1, [$r0], $r1 ! Copy the word to det
bnez $p1, word_set ! Still words to set, continue looping
beqz $r2, end_memset ! No left byte to set
byte_set: ! Less than 4 bytes left to set
addi $r2, $r2, #-1 ! Decrease len by 1
sbi.bi $r1, [$r0], #1 ! Set data of the next byte to $r1
bnez $r2, byte_set ! Still bytes left to set
end_memset:
move $r0, $r5
ret
ENDPROC(memset)
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