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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 .text
17
18/*
19 * Prototype: void *memmove(void *dest, const void *src, size_t n);
20 *
21 * Note:
22 *
23 * If the memory regions don't overlap, we simply branch to memcpy which is
24 * normally a bit faster. Otherwise the copy is done going downwards. This
25 * is a transposition of the code from copy_template.S but with the copy
26 * occurring in the opposite direction.
27 */
28
29ENTRY(memmove)
30
31 subs ip, r0, r1
32 cmphi r2, ip
33 bls memcpy
34
35 stmfd sp!, {r0, r4, lr}
36 add r1, r1, r2
37 add r0, r0, r2
38 subs r2, r2, #4
39 blt 8f
40 ands ip, r0, #3
41 PLD( pld [r1, #-4] )
42 bne 9f
43 ands ip, r1, #3
44 bne 10f
45
461: subs r2, r2, #(28)
47 stmfd sp!, {r5 - r8}
48 blt 5f
49
50 CALGN( ands ip, r0, #31 )
51 CALGN( sbcnes r4, ip, r2 ) @ C is always set here
52 CALGN( bcs 2f )
53 CALGN( adr r4, 6f )
54 CALGN( subs r2, r2, ip ) @ C is set here
55 CALGN( rsb ip, ip, #32 )
56 CALGN( add pc, r4, ip )
57
58 PLD( pld [r1, #-4] )
592: PLD( subs r2, r2, #96 )
60 PLD( pld [r1, #-32] )
61 PLD( blt 4f )
62 PLD( pld [r1, #-64] )
63 PLD( pld [r1, #-96] )
64
653: PLD( pld [r1, #-128] )
664: ldmdb r1!, {r3, r4, r5, r6, r7, r8, ip, lr}
67 subs r2, r2, #32
68 stmdb r0!, {r3, r4, r5, r6, r7, r8, ip, lr}
69 bge 3b
70 PLD( cmn r2, #96 )
71 PLD( bge 4b )
72
735: ands ip, r2, #28
74 rsb ip, ip, #32
75 addne pc, pc, ip @ C is always clear here
76 b 7f
776: W(nop)
78 W(ldr) r3, [r1, #-4]!
79 W(ldr) r4, [r1, #-4]!
80 W(ldr) r5, [r1, #-4]!
81 W(ldr) r6, [r1, #-4]!
82 W(ldr) r7, [r1, #-4]!
83 W(ldr) r8, [r1, #-4]!
84 W(ldr) lr, [r1, #-4]!
85
86 add pc, pc, ip
87 nop
88 W(nop)
89 W(str) r3, [r0, #-4]!
90 W(str) r4, [r0, #-4]!
91 W(str) r5, [r0, #-4]!
92 W(str) r6, [r0, #-4]!
93 W(str) r7, [r0, #-4]!
94 W(str) r8, [r0, #-4]!
95 W(str) lr, [r0, #-4]!
96
97 CALGN( bcs 2b )
98
997: ldmfd sp!, {r5 - r8}
100
1018: movs r2, r2, lsl #31
102 ldrneb r3, [r1, #-1]!
103 ldrcsb r4, [r1, #-1]!
104 ldrcsb ip, [r1, #-1]
105 strneb r3, [r0, #-1]!
106 strcsb r4, [r0, #-1]!
107 strcsb ip, [r0, #-1]
108 ldmfd sp!, {r0, r4, pc}
109
1109: cmp ip, #2
111 ldrgtb r3, [r1, #-1]!
112 ldrgeb r4, [r1, #-1]!
113 ldrb lr, [r1, #-1]!
114 strgtb r3, [r0, #-1]!
115 strgeb r4, [r0, #-1]!
116 subs r2, r2, ip
117 strb lr, [r0, #-1]!
118 blt 8b
119 ands ip, r1, #3
120 beq 1b
121
12210: bic r1, r1, #3
123 cmp ip, #2
124 ldr r3, [r1, #0]
125 beq 17f
126 blt 18f
127
128
129 .macro backward_copy_shift push pull
130
131 subs r2, r2, #28
132 blt 14f
133
134 CALGN( ands ip, r0, #31 )
135 CALGN( sbcnes r4, ip, r2 ) @ C is always set here
136 CALGN( subcc r2, r2, ip )
137 CALGN( bcc 15f )
138
13911: stmfd sp!, {r5 - r9}
140
141 PLD( pld [r1, #-4] )
142 PLD( subs r2, r2, #96 )
143 PLD( pld [r1, #-32] )
144 PLD( blt 13f )
145 PLD( pld [r1, #-64] )
146 PLD( pld [r1, #-96] )
147
14812: PLD( pld [r1, #-128] )
14913: ldmdb r1!, {r7, r8, r9, ip}
150 mov lr, r3, lspush #\push
151 subs r2, r2, #32
152 ldmdb r1!, {r3, r4, r5, r6}
153 orr lr, lr, ip, lspull #\pull
154 mov ip, ip, lspush #\push
155 orr ip, ip, r9, lspull #\pull
156 mov r9, r9, lspush #\push
157 orr r9, r9, r8, lspull #\pull
158 mov r8, r8, lspush #\push
159 orr r8, r8, r7, lspull #\pull
160 mov r7, r7, lspush #\push
161 orr r7, r7, r6, lspull #\pull
162 mov r6, r6, lspush #\push
163 orr r6, r6, r5, lspull #\pull
164 mov r5, r5, lspush #\push
165 orr r5, r5, r4, lspull #\pull
166 mov r4, r4, lspush #\push
167 orr r4, r4, r3, lspull #\pull
168 stmdb r0!, {r4 - r9, ip, lr}
169 bge 12b
170 PLD( cmn r2, #96 )
171 PLD( bge 13b )
172
173 ldmfd sp!, {r5 - r9}
174
17514: ands ip, r2, #28
176 beq 16f
177
17815: mov lr, r3, lspush #\push
179 ldr r3, [r1, #-4]!
180 subs ip, ip, #4
181 orr lr, lr, r3, lspull #\pull
182 str lr, [r0, #-4]!
183 bgt 15b
184 CALGN( cmp r2, #0 )
185 CALGN( bge 11b )
186
18716: add r1, r1, #(\pull / 8)
188 b 8b
189
190 .endm
191
192
193 backward_copy_shift push=8 pull=24
194
19517: backward_copy_shift push=16 pull=16
196
19718: backward_copy_shift push=24 pull=8
198
199ENDPROC(memmove)