54 строки
1.3 KiB
ArmAsm
54 строки
1.3 KiB
ArmAsm
/*
|
|
* linux/arch/arm/lib/clear_user.S
|
|
*
|
|
* Copyright (C) 1995, 1996,1997,1998 Russell King
|
|
*
|
|
* 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.
|
|
*/
|
|
#include <linux/linkage.h>
|
|
#include <asm/assembler.h>
|
|
|
|
.text
|
|
|
|
/* Prototype: int __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
|
|
*/
|
|
ENTRY(__clear_user)
|
|
stmfd sp!, {r1, lr}
|
|
mov r2, #0
|
|
cmp r1, #4
|
|
blt 2f
|
|
ands ip, r0, #3
|
|
beq 1f
|
|
cmp ip, #2
|
|
USER( strbt r2, [r0], #1)
|
|
USER( strlebt r2, [r0], #1)
|
|
USER( strltbt r2, [r0], #1)
|
|
rsb ip, ip, #4
|
|
sub r1, r1, ip @ 7 6 5 4 3 2 1
|
|
1: subs r1, r1, #8 @ -1 -2 -3 -4 -5 -6 -7
|
|
USER( strplt r2, [r0], #4)
|
|
USER( strplt r2, [r0], #4)
|
|
bpl 1b
|
|
adds r1, r1, #4 @ 3 2 1 0 -1 -2 -3
|
|
USER( strplt r2, [r0], #4)
|
|
2: tst r1, #2 @ 1x 1x 0x 0x 1x 1x 0x
|
|
USER( strnebt r2, [r0], #1)
|
|
USER( strnebt r2, [r0], #1)
|
|
tst r1, #1 @ x1 x0 x1 x0 x1 x0 x1
|
|
USER( strnebt r2, [r0])
|
|
mov r0, #0
|
|
ldmfd sp!, {r1, pc}
|
|
ENDPROC(__clear_user)
|
|
|
|
.section .fixup,"ax"
|
|
.align 0
|
|
9001: ldmfd sp!, {r0, pc}
|
|
.previous
|
|
|