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1da177e4 LT |
1 | /* |
2 | * linux/arch/arm26/lib/memset.S | |
3 | * | |
4 | * Copyright (C) 1995-2000 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 | * ASM optimised string functions | |
11 | */ | |
12 | #include <linux/linkage.h> | |
13 | #include <asm/assembler.h> | |
14 | ||
15 | .text | |
16 | .align 5 | |
17 | .word 0 | |
18 | ||
19 | 1: subs r2, r2, #4 @ 1 do we have enough | |
20 | blt 5f @ 1 bytes to align with? | |
21 | cmp r3, #2 @ 1 | |
22 | strltb r1, [r0], #1 @ 1 | |
23 | strleb r1, [r0], #1 @ 1 | |
24 | strb r1, [r0], #1 @ 1 | |
25 | add r2, r2, r3 @ 1 (r2 = r2 - (4 - r3)) | |
26 | /* | |
27 | * The pointer is now aligned and the length is adjusted. Try doing the | |
28 | * memzero again. | |
29 | */ | |
30 | ||
31 | ENTRY(memset) | |
32 | ands r3, r0, #3 @ 1 unaligned? | |
33 | bne 1b @ 1 | |
34 | /* | |
35 | * we know that the pointer in r0 is aligned to a word boundary. | |
36 | */ | |
37 | orr r1, r1, r1, lsl #8 | |
38 | orr r1, r1, r1, lsl #16 | |
39 | mov r3, r1 | |
40 | cmp r2, #16 | |
41 | blt 4f | |
42 | /* | |
43 | * We need an extra register for this loop - save the return address and | |
44 | * use the LR | |
45 | */ | |
46 | str lr, [sp, #-4]! | |
47 | mov ip, r1 | |
48 | mov lr, r1 | |
49 | ||
50 | 2: subs r2, r2, #64 | |
51 | stmgeia r0!, {r1, r3, ip, lr} @ 64 bytes at a time. | |
52 | stmgeia r0!, {r1, r3, ip, lr} | |
53 | stmgeia r0!, {r1, r3, ip, lr} | |
54 | stmgeia r0!, {r1, r3, ip, lr} | |
55 | bgt 2b | |
56 | LOADREGS(eqfd, sp!, {pc}) @ Now <64 bytes to go. | |
57 | /* | |
58 | * No need to correct the count; we're only testing bits from now on | |
59 | */ | |
60 | tst r2, #32 | |
61 | stmneia r0!, {r1, r3, ip, lr} | |
62 | stmneia r0!, {r1, r3, ip, lr} | |
63 | tst r2, #16 | |
64 | stmneia r0!, {r1, r3, ip, lr} | |
65 | ldr lr, [sp], #4 | |
66 | ||
67 | 4: tst r2, #8 | |
68 | stmneia r0!, {r1, r3} | |
69 | tst r2, #4 | |
70 | strne r1, [r0], #4 | |
71 | /* | |
72 | * When we get here, we've got less than 4 bytes to zero. We | |
73 | * may have an unaligned pointer as well. | |
74 | */ | |
75 | 5: tst r2, #2 | |
76 | strneb r1, [r0], #1 | |
77 | strneb r1, [r0], #1 | |
78 | tst r2, #1 | |
79 | strneb r1, [r0], #1 | |
80 | RETINSTR(mov,pc,lr) |