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// SPDX-License-Identifier: GPL-2.0
// Copyright (C) 2005-2017 Andes Technology Corporation
#include <linux/linkage.h>
#include <asm/assembler.h>
#include <asm/errno.h>
/* Prototype: int __arch_clear_user(void *addr, size_t sz)
* Purpose : clear some user memory
* Params : addr - user memory address to clear
* : sz - number of bytes to clear
* Returns : number of bytes NOT cleared
*/
.text
.align 5
ENTRY(__arch_clear_user)
add $r5, $r0, $r1
beqz $r1, clear_exit
xor $p1, $p1, $p1 ! Use $p1=0 to clear mem
srli $p0, $r1, #2 ! $p0 = number of word to clear
andi $r1, $r1, #3 ! Bytes less than a word to copy
beqz $p0, byte_clear ! Only less than a word to clear
word_clear:
USER( smw.bim,$p1, [$r0], $p1) ! Clear the word
addi $p0, $p0, #-1 ! Decrease word count
bnez $p0, word_clear ! Continue looping to clear all words
beqz $r1, clear_exit ! No left bytes to copy
byte_clear:
USER( sbi.bi, $p1, [$r0], #1) ! Clear the byte
addi $r1, $r1, #-1 ! Decrease byte count
bnez $r1, byte_clear ! Continue looping to clear all left bytes
clear_exit:
move $r0, $r1 ! Set return value
ret
.section .fixup,"ax"
.align 0
9001:
sub $r0, $r5, $r0 ! Bytes left to copy
ret
.previous
ENDPROC(__arch_clear_user)
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