Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * linux/arch/arm/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 | |
59f0cb0f | 28 | * memset again. |
1da177e4 LT |
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 | |
f91a8dcc NP |
42 | |
43 | #if ! CALGN(1)+0 | |
44 | ||
1da177e4 LT |
45 | /* |
46 | * We need an extra register for this loop - save the return address and | |
47 | * use the LR | |
48 | */ | |
49 | str lr, [sp, #-4]! | |
50 | mov ip, r1 | |
51 | mov lr, r1 | |
52 | ||
53 | 2: subs r2, r2, #64 | |
54 | stmgeia r0!, {r1, r3, ip, lr} @ 64 bytes at a time. | |
55 | stmgeia r0!, {r1, r3, ip, lr} | |
56 | stmgeia r0!, {r1, r3, ip, lr} | |
57 | stmgeia r0!, {r1, r3, ip, lr} | |
58 | bgt 2b | |
1b93a717 | 59 | ldmeqfd sp!, {pc} @ Now <64 bytes to go. |
1da177e4 LT |
60 | /* |
61 | * No need to correct the count; we're only testing bits from now on | |
62 | */ | |
63 | tst r2, #32 | |
64 | stmneia r0!, {r1, r3, ip, lr} | |
65 | stmneia r0!, {r1, r3, ip, lr} | |
66 | tst r2, #16 | |
67 | stmneia r0!, {r1, r3, ip, lr} | |
68 | ldr lr, [sp], #4 | |
69 | ||
f91a8dcc NP |
70 | #else |
71 | ||
72 | /* | |
73 | * This version aligns the destination pointer in order to write | |
74 | * whole cache lines at once. | |
75 | */ | |
76 | ||
77 | stmfd sp!, {r4-r7, lr} | |
78 | mov r4, r1 | |
79 | mov r5, r1 | |
80 | mov r6, r1 | |
81 | mov r7, r1 | |
82 | mov ip, r1 | |
83 | mov lr, r1 | |
84 | ||
85 | cmp r2, #96 | |
86 | tstgt r0, #31 | |
87 | ble 3f | |
88 | ||
89 | and ip, r0, #31 | |
90 | rsb ip, ip, #32 | |
91 | sub r2, r2, ip | |
92 | movs ip, ip, lsl #(32 - 4) | |
93 | stmcsia r0!, {r4, r5, r6, r7} | |
94 | stmmiia r0!, {r4, r5} | |
95 | tst ip, #(1 << 30) | |
96 | mov ip, r1 | |
97 | strne r1, [r0], #4 | |
98 | ||
99 | 3: subs r2, r2, #64 | |
100 | stmgeia r0!, {r1, r3-r7, ip, lr} | |
101 | stmgeia r0!, {r1, r3-r7, ip, lr} | |
102 | bgt 3b | |
103 | ldmeqfd sp!, {r4-r7, pc} | |
104 | ||
105 | tst r2, #32 | |
106 | stmneia r0!, {r1, r3-r7, ip, lr} | |
107 | tst r2, #16 | |
108 | stmneia r0!, {r4-r7} | |
109 | ldmfd sp!, {r4-r7, lr} | |
110 | ||
111 | #endif | |
112 | ||
1da177e4 LT |
113 | 4: tst r2, #8 |
114 | stmneia r0!, {r1, r3} | |
115 | tst r2, #4 | |
116 | strne r1, [r0], #4 | |
117 | /* | |
118 | * When we get here, we've got less than 4 bytes to zero. We | |
119 | * may have an unaligned pointer as well. | |
120 | */ | |
121 | 5: tst r2, #2 | |
122 | strneb r1, [r0], #1 | |
123 | strneb r1, [r0], #1 | |
124 | tst r2, #1 | |
125 | strneb r1, [r0], #1 | |
7999d8d7 | 126 | mov pc, lr |
93ed3970 | 127 | ENDPROC(memset) |