projects / linux-2.6-block.git / blame
| Commit | Line | Data |
|---|---|---|
| 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 | ||
| 02fcb974 | 15 | /* Prototype: int __clear_user(void *addr, size_t sz) |
| a0c6fdb9 NP |
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 | */ | |
| a1f98849 NP |
21 | ENTRY(__clear_user_std) |
| 22 | WEAK(__clear_user) | |
| a0c6fdb9 NP |
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 | |
| 8b592783 CM |
30 | strusr r2, r0, 1 |
| 31 | strusr r2, r0, 1, le | |
| 32 | strusr r2, r0, 1, lt | |
| a0c6fdb9 NP |
33 | rsb ip, ip, #4 |
| 34 | sub r1, r1, ip @ 7 6 5 4 3 2 1 | |
| 35 | 1: subs r1, r1, #8 @ -1 -2 -3 -4 -5 -6 -7 | |
| 8b592783 | 36 | strusr r2, r0, 4, pl, rept=2 |
| a0c6fdb9 NP |
37 | bpl 1b |
| 38 | adds r1, r1, #4 @ 3 2 1 0 -1 -2 -3 | |
| 8b592783 | 39 | strusr r2, r0, 4, pl |
| a0c6fdb9 | 40 | 2: 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 | 44 | USER( strnebt r2, [r0]) |
| a0c6fdb9 | 45 | mov r0, #0 |
| 1b93a717 | 46 | ldmfd sp!, {r1, pc} |
| 93ed3970 | 47 | ENDPROC(__clear_user) |
| e814d826 | 48 | ENDPROC(__clear_user_std) |
| a0c6fdb9 | 49 | |
| c4a84ae3 | 50 | .pushsection .text.fixup,"ax" |
| a0c6fdb9 | 51 | .align 0 |
| 1b93a717 | 52 | 9001: ldmfd sp!, {r0, pc} |
| 4260415f | 53 | .popsection |
| a0c6fdb9 | 54 |