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a0c6fdb9 NP |
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 | ||
15 | /* Prototype: int __arch_clear_user(void *addr, size_t sz) | |
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 | */ | |
21 | ENTRY(__arch_clear_user) | |
22 | stmfd sp!, {r1, lr} | |
23 | mov r2, #0 | |
24 | cmp r1, #4 | |
25 | blt 2f | |
26 | ands ip, r0, #3 | |
27 | beq 1f | |
28 | cmp ip, #2 | |
29 | USER( strbt r2, [r0], #1) | |
30 | USER( strlebt r2, [r0], #1) | |
31 | USER( strltbt r2, [r0], #1) | |
32 | rsb ip, ip, #4 | |
33 | sub r1, r1, ip @ 7 6 5 4 3 2 1 | |
34 | 1: subs r1, r1, #8 @ -1 -2 -3 -4 -5 -6 -7 | |
35 | USER( strplt r2, [r0], #4) | |
36 | USER( strplt r2, [r0], #4) | |
37 | bpl 1b | |
38 | adds r1, r1, #4 @ 3 2 1 0 -1 -2 -3 | |
39 | USER( strplt r2, [r0], #4) | |
40 | 2: tst r1, #2 @ 1x 1x 0x 0x 1x 1x 0x | |
41 | USER( strnebt r2, [r0], #1) | |
42 | USER( strnebt r2, [r0], #1) | |
43 | tst r1, #1 @ x1 x0 x1 x0 x1 x0 x1 | |
44 | USER( strnebt r2, [r0], #1) | |
45 | mov r0, #0 | |
46 | LOADREGS(fd,sp!, {r1, pc}) | |
47 | ||
48 | .section .fixup,"ax" | |
49 | .align 0 | |
50 | 9001: LOADREGS(fd,sp!, {r0, pc}) | |
51 | .previous | |
52 |