Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph...
[linux-2.6-block.git] / arch / arm / lib / clear_user.S
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1/*
2 * linux/arch/arm/lib/clear_user.S
3 *
4 * Copyright (C) 1995, 1996,1997,1998 Russell King
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 */
10#include <linux/linkage.h>
11#include <asm/assembler.h>
12
13 .text
14
02fcb974 15/* Prototype: int __clear_user(void *addr, size_t sz)
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16 * Purpose : clear some user memory
17 * Params : addr - user memory address to clear
18 * : sz - number of bytes to clear
19 * Returns : number of bytes NOT cleared
20 */
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21ENTRY(__clear_user_std)
22WEAK(__clear_user)
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23 stmfd sp!, {r1, lr}
24 mov r2, #0
25 cmp r1, #4
26 blt 2f
27 ands ip, r0, #3
28 beq 1f
29 cmp ip, #2
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CM
30 strusr r2, r0, 1
31 strusr r2, r0, 1, le
32 strusr r2, r0, 1, lt
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33 rsb ip, ip, #4
34 sub r1, r1, ip @ 7 6 5 4 3 2 1
351: subs r1, r1, #8 @ -1 -2 -3 -4 -5 -6 -7
8b592783 36 strusr r2, r0, 4, pl, rept=2
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37 bpl 1b
38 adds r1, r1, #4 @ 3 2 1 0 -1 -2 -3
8b592783 39 strusr r2, r0, 4, pl
a0c6fdb9 402: tst r1, #2 @ 1x 1x 0x 0x 1x 1x 0x
8b592783 41 strusr r2, r0, 1, ne, rept=2
a0c6fdb9 42 tst r1, #1 @ x1 x0 x1 x0 x1 x0 x1
8b592783 43 it ne @ explicit IT needed for the label
9c23e5fe 44USER( strnebt r2, [r0])
a0c6fdb9 45 mov r0, #0
1b93a717 46 ldmfd sp!, {r1, pc}
93ed3970 47ENDPROC(__clear_user)
e814d826 48ENDPROC(__clear_user_std)
a0c6fdb9 49
c4a84ae3 50 .pushsection .text.fixup,"ax"
a0c6fdb9 51 .align 0
1b93a717 529001: ldmfd sp!, {r0, pc}
4260415f 53 .popsection
a0c6fdb9 54