Commit | Line | Data |
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77c93b2f G |
1 | /* |
2 | * linux/arch/unicore32/lib/clear_user.S | |
3 | * | |
4 | * Code specific to PKUnity SoC and UniCore ISA | |
5 | * | |
6 | * Copyright (C) 2001-2010 GUAN Xue-tao | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or modify | |
9 | * it under the terms of the GNU General Public License version 2 as | |
10 | * published by the Free Software Foundation. | |
11 | */ | |
12 | #include <linux/linkage.h> | |
13 | #include <asm/assembler.h> | |
14 | ||
15 | .text | |
16 | ||
17 | /* Prototype: int __clear_user(void *addr, size_t sz) | |
18 | * Purpose : clear some user memory | |
19 | * Params : addr - user memory address to clear | |
20 | * : sz - number of bytes to clear | |
21 | * Returns : number of bytes NOT cleared | |
22 | */ | |
23 | WEAK(__clear_user) | |
24 | stm.w (lr), [sp-] | |
25 | stm.w (r1), [sp-] | |
26 | mov r2, #0 | |
27 | csub.a r1, #4 | |
28 | bsl 2f | |
29 | and.a ip, r0, #3 | |
30 | beq 1f | |
31 | csub.a ip, #2 | |
32 | strusr r2, r0, 1 | |
33 | strusr r2, r0, 1, el | |
34 | strusr r2, r0, 1, sl | |
35 | rsub ip, ip, #4 | |
36 | sub r1, r1, ip @ 7 6 5 4 3 2 1 | |
37 | 1: sub.a r1, r1, #8 @ -1 -2 -3 -4 -5 -6 -7 | |
38 | strusr r2, r0, 4, ns, rept=2 | |
39 | bns 1b | |
40 | add.a r1, r1, #4 @ 3 2 1 0 -1 -2 -3 | |
41 | strusr r2, r0, 4, ns | |
42 | 2: cand.a r1, #2 @ 1x 1x 0x 0x 1x 1x 0x | |
43 | strusr r2, r0, 1, ne, rept=2 | |
44 | cand.a r1, #1 @ x1 x0 x1 x0 x1 x0 x1 | |
45 | beq 3f | |
46 | USER( stb.u r2, [r0]) | |
47 | 3: mov r0, #0 | |
48 | ldm.w (r1), [sp]+ | |
49 | ldm.w (pc), [sp]+ | |
50 | ENDPROC(__clear_user) | |
51 | ||
52 | .pushsection .fixup,"ax" | |
53 | .align 0 | |
54 | 9001: ldm.w (r0), [sp]+ | |
55 | ldm.w (pc), [sp]+ | |
56 | .popsection | |
57 |