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Diffstat (limited to 'arch/arm/lib/memmove.S')
-rw-r--r-- | arch/arm/lib/memmove.S | 206 |
1 files changed, 206 insertions, 0 deletions
diff --git a/arch/arm/lib/memmove.S b/arch/arm/lib/memmove.S new file mode 100644 index 000000000000..ef7fddc14ac9 --- /dev/null +++ b/arch/arm/lib/memmove.S | |||
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1 | /* | ||
2 | * linux/arch/arm/lib/memmove.S | ||
3 | * | ||
4 | * Author: Nicolas Pitre | ||
5 | * Created: Sep 28, 2005 | ||
6 | * Copyright: (C) MontaVista Software Inc. | ||
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 | |||
13 | #include <linux/linkage.h> | ||
14 | #include <asm/assembler.h> | ||
15 | |||
16 | /* | ||
17 | * This can be used to enable code to cacheline align the source pointer. | ||
18 | * Experiments on tested architectures (StrongARM and XScale) didn't show | ||
19 | * this a worthwhile thing to do. That might be different in the future. | ||
20 | */ | ||
21 | //#define CALGN(code...) code | ||
22 | #define CALGN(code...) | ||
23 | |||
24 | .text | ||
25 | |||
26 | /* | ||
27 | * Prototype: void *memmove(void *dest, const void *src, size_t n); | ||
28 | * | ||
29 | * Note: | ||
30 | * | ||
31 | * If the memory regions don't overlap, we simply branch to memcpy which is | ||
32 | * normally a bit faster. Otherwise the copy is done going downwards. This | ||
33 | * is a transposition of the code from copy_template.S but with the copy | ||
34 | * occurring in the opposite direction. | ||
35 | */ | ||
36 | |||
37 | ENTRY(memmove) | ||
38 | |||
39 | subs ip, r0, r1 | ||
40 | cmphi r2, ip | ||
41 | bls memcpy | ||
42 | |||
43 | stmfd sp!, {r0, r4, lr} | ||
44 | add r1, r1, r2 | ||
45 | add r0, r0, r2 | ||
46 | subs r2, r2, #4 | ||
47 | blt 8f | ||
48 | ands ip, r0, #3 | ||
49 | PLD( pld [r1, #-4] ) | ||
50 | bne 9f | ||
51 | ands ip, r1, #3 | ||
52 | bne 10f | ||
53 | |||
54 | 1: subs r2, r2, #(28) | ||
55 | stmfd sp!, {r5 - r8} | ||
56 | blt 5f | ||
57 | |||
58 | CALGN( ands ip, r1, #31 ) | ||
59 | CALGN( sbcnes r4, ip, r2 ) @ C is always set here | ||
60 | CALGN( bcs 2f ) | ||
61 | CALGN( adr r4, 6f ) | ||
62 | CALGN( subs r2, r2, ip ) @ C is set here | ||
63 | CALGN( add pc, r4, ip ) | ||
64 | |||
65 | PLD( pld [r1, #-4] ) | ||
66 | 2: PLD( subs r2, r2, #96 ) | ||
67 | PLD( pld [r1, #-32] ) | ||
68 | PLD( blt 4f ) | ||
69 | PLD( pld [r1, #-64] ) | ||
70 | PLD( pld [r1, #-96] ) | ||
71 | |||
72 | 3: PLD( pld [r1, #-128] ) | ||
73 | 4: ldmdb r1!, {r3, r4, r5, r6, r7, r8, ip, lr} | ||
74 | subs r2, r2, #32 | ||
75 | stmdb r0!, {r3, r4, r5, r6, r7, r8, ip, lr} | ||
76 | bge 3b | ||
77 | PLD( cmn r2, #96 ) | ||
78 | PLD( bge 4b ) | ||
79 | |||
80 | 5: ands ip, r2, #28 | ||
81 | rsb ip, ip, #32 | ||
82 | addne pc, pc, ip @ C is always clear here | ||
83 | b 7f | ||
84 | 6: nop | ||
85 | ldr r3, [r1, #-4]! | ||
86 | ldr r4, [r1, #-4]! | ||
87 | ldr r5, [r1, #-4]! | ||
88 | ldr r6, [r1, #-4]! | ||
89 | ldr r7, [r1, #-4]! | ||
90 | ldr r8, [r1, #-4]! | ||
91 | ldr lr, [r1, #-4]! | ||
92 | |||
93 | add pc, pc, ip | ||
94 | nop | ||
95 | nop | ||
96 | str r3, [r0, #-4]! | ||
97 | str r4, [r0, #-4]! | ||
98 | str r5, [r0, #-4]! | ||
99 | str r6, [r0, #-4]! | ||
100 | str r7, [r0, #-4]! | ||
101 | str r8, [r0, #-4]! | ||
102 | str lr, [r0, #-4]! | ||
103 | |||
104 | CALGN( bcs 2b ) | ||
105 | |||
106 | 7: ldmfd sp!, {r5 - r8} | ||
107 | |||
108 | 8: movs r2, r2, lsl #31 | ||
109 | ldrneb r3, [r1, #-1]! | ||
110 | ldrcsb r4, [r1, #-1]! | ||
111 | ldrcsb ip, [r1, #-1] | ||
112 | strneb r3, [r0, #-1]! | ||
113 | strcsb r4, [r0, #-1]! | ||
114 | strcsb ip, [r0, #-1] | ||
115 | ldmfd sp!, {r0, r4, pc} | ||
116 | |||
117 | 9: cmp ip, #2 | ||
118 | ldrgtb r3, [r1, #-1]! | ||
119 | ldrgeb r4, [r1, #-1]! | ||
120 | ldrb lr, [r1, #-1]! | ||
121 | strgtb r3, [r0, #-1]! | ||
122 | strgeb r4, [r0, #-1]! | ||
123 | subs r2, r2, ip | ||
124 | strb lr, [r0, #-1]! | ||
125 | blt 8b | ||
126 | ands ip, r1, #3 | ||
127 | beq 1b | ||
128 | |||
129 | 10: bic r1, r1, #3 | ||
130 | cmp ip, #2 | ||
131 | ldr r3, [r1, #0] | ||
132 | beq 17f | ||
133 | blt 18f | ||
134 | |||
135 | |||
136 | .macro backward_copy_shift push pull | ||
137 | |||
138 | subs r2, r2, #28 | ||
139 | blt 14f | ||
140 | |||
141 | CALGN( ands ip, r1, #31 ) | ||
142 | CALGN( rsb ip, ip, #32 ) | ||
143 | CALGN( sbcnes r4, ip, r2 ) @ C is always set here | ||
144 | CALGN( subcc r2, r2, ip ) | ||
145 | CALGN( bcc 15f ) | ||
146 | |||
147 | 11: stmfd sp!, {r5 - r9} | ||
148 | |||
149 | PLD( pld [r1, #-4] ) | ||
150 | PLD( subs r2, r2, #96 ) | ||
151 | PLD( pld [r1, #-32] ) | ||
152 | PLD( blt 13f ) | ||
153 | PLD( pld [r1, #-64] ) | ||
154 | PLD( pld [r1, #-96] ) | ||
155 | |||
156 | 12: PLD( pld [r1, #-128] ) | ||
157 | 13: ldmdb r1!, {r7, r8, r9, ip} | ||
158 | mov lr, r3, push #\push | ||
159 | subs r2, r2, #32 | ||
160 | ldmdb r1!, {r3, r4, r5, r6} | ||
161 | orr lr, lr, ip, pull #\pull | ||
162 | mov ip, ip, push #\push | ||
163 | orr ip, ip, r9, pull #\pull | ||
164 | mov r9, r9, push #\push | ||
165 | orr r9, r9, r8, pull #\pull | ||
166 | mov r8, r8, push #\push | ||
167 | orr r8, r8, r7, pull #\pull | ||
168 | mov r7, r7, push #\push | ||
169 | orr r7, r7, r6, pull #\pull | ||
170 | mov r6, r6, push #\push | ||
171 | orr r6, r6, r5, pull #\pull | ||
172 | mov r5, r5, push #\push | ||
173 | orr r5, r5, r4, pull #\pull | ||
174 | mov r4, r4, push #\push | ||
175 | orr r4, r4, r3, pull #\pull | ||
176 | stmdb r0!, {r4 - r9, ip, lr} | ||
177 | bge 12b | ||
178 | PLD( cmn r2, #96 ) | ||
179 | PLD( bge 13b ) | ||
180 | |||
181 | ldmfd sp!, {r5 - r9} | ||
182 | |||
183 | 14: ands ip, r2, #28 | ||
184 | beq 16f | ||
185 | |||
186 | 15: mov lr, r3, push #\push | ||
187 | ldr r3, [r1, #-4]! | ||
188 | subs ip, ip, #4 | ||
189 | orr lr, lr, r3, pull #\pull | ||
190 | str lr, [r0, #-4]! | ||
191 | bgt 15b | ||
192 | CALGN( cmp r2, #0 ) | ||
193 | CALGN( bge 11b ) | ||
194 | |||
195 | 16: add r1, r1, #(\pull / 8) | ||
196 | b 8b | ||
197 | |||
198 | .endm | ||
199 | |||
200 | |||
201 | backward_copy_shift push=8 pull=24 | ||
202 | |||
203 | 17: backward_copy_shift push=16 pull=16 | ||
204 | |||
205 | 18: backward_copy_shift push=24 pull=8 | ||
206 | |||