1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3 * linux/arch/arm/lib/memmove.S
4 *
5 * Author: Nicolas Pitre
6 * Created: Sep 28, 2005
7 * Copyright: (C) MontaVista Software Inc.
8 */
9
10 #include <linux/linkage.h>
11 #include <asm/assembler.h>
12 #include <asm/unwind.h>
13
14 .text
15
16 /*
17 * Prototype: void *memmove(void *dest, const void *src, size_t n);
18 *
19 * Note:
20 *
21 * If the memory regions don't overlap, we simply branch to memcpy which is
22 * normally a bit faster. Otherwise the copy is done going downwards. This
23 * is a transposition of the code from copy_template.S but with the copy
24 * occurring in the opposite direction.
25 */
26
27 ENTRY(__memmove)
28 WEAK(memmove)
29 UNWIND( .fnstart )
30
31 subs ip, r0, r1
32 cmphi r2, ip
33 bls __memcpy
34 UNWIND( .fnend )
35
36 UNWIND( .fnstart )
37 UNWIND( .save {r0, r4, fpreg, lr} )
38 stmfd sp!, {r0, r4, UNWIND(fpreg,) lr}
39 UNWIND( .setfp fpreg, sp )
40 UNWIND( mov fpreg, sp )
41 add r1, r1, r2
42 add r0, r0, r2
43 subs r2, r2, #4
44 blt 8f
45 ands ip, r0, #3
46 PLD( pld [r1, #-4] )
47 bne 9f
48 ands ip, r1, #3
49 bne 10f
50
51 1: subs r2, r2, #(28)
52 stmfd sp!, {r5, r6, r8, r9}
53 blt 5f
54
55 CALGN( ands ip, r0, #31 )
56 CALGN( sbcsne r4, ip, r2 ) @ C is always set here
57 CALGN( bcs 2f )
58 CALGN( adr r4, 6f )
59 CALGN( subs r2, r2, ip ) @ C is set here
60 CALGN( rsb ip, ip, #32 )
61 CALGN( add pc, r4, ip )
62
63 PLD( pld [r1, #-4] )
64 2: PLD( subs r2, r2, #96 )
65 PLD( pld [r1, #-32] )
66 PLD( blt 4f )
67 PLD( pld [r1, #-64] )
68 PLD( pld [r1, #-96] )
69
70 3: PLD( pld [r1, #-128] )
71 4: ldmdb r1!, {r3, r4, r5, r6, r8, r9, ip, lr}
72 subs r2, r2, #32
73 stmdb r0!, {r3, r4, r5, r6, r8, r9, ip, lr}
74 bge 3b
75 PLD( cmn r2, #96 )
76 PLD( bge 4b )
77
78 5: ands ip, r2, #28
79 rsb ip, ip, #32
80 addne pc, pc, ip @ C is always clear here
81 b 7f
82 6: W(nop)
83 W(ldr) r3, [r1, #-4]!
84 W(ldr) r4, [r1, #-4]!
85 W(ldr) r5, [r1, #-4]!
86 W(ldr) r6, [r1, #-4]!
87 W(ldr) r8, [r1, #-4]!
88 W(ldr) r9, [r1, #-4]!
89 W(ldr) lr, [r1, #-4]!
90
91 add pc, pc, ip
92 nop
93 W(nop)
94 W(str) r3, [r0, #-4]!
95 W(str) r4, [r0, #-4]!
96 W(str) r5, [r0, #-4]!
97 W(str) r6, [r0, #-4]!
98 W(str) r8, [r0, #-4]!
99 W(str) r9, [r0, #-4]!
100 W(str) lr, [r0, #-4]!
101
102 CALGN( bcs 2b )
103
104 7: ldmfd sp!, {r5, r6, r8, r9}
105
106 8: movs r2, r2, lsl #31
107 ldrbne r3, [r1, #-1]!
108 ldrbcs r4, [r1, #-1]!
109 ldrbcs ip, [r1, #-1]
110 strbne r3, [r0, #-1]!
111 strbcs r4, [r0, #-1]!
112 strbcs ip, [r0, #-1]
113 ldmfd sp!, {r0, r4, UNWIND(fpreg,) pc}
114
115 9: cmp ip, #2
116 ldrbgt r3, [r1, #-1]!
117 ldrbge r4, [r1, #-1]!
118 ldrb lr, [r1, #-1]!
119 strbgt r3, [r0, #-1]!
120 strbge r4, [r0, #-1]!
121 subs r2, r2, ip
122 strb lr, [r0, #-1]!
123 blt 8b
124 ands ip, r1, #3
125 beq 1b
126
127 10: bic r1, r1, #3
128 cmp ip, #2
129 ldr r3, [r1, #0]
130 beq 17f
131 blt 18f
132
133
134 .macro backward_copy_shift push pull
135
136 subs r2, r2, #28
137 blt 14f
138
139 CALGN( ands ip, r0, #31 )
140 CALGN( sbcsne r4, ip, r2 ) @ C is always set here
141 CALGN( subcc r2, r2, ip )
142 CALGN( bcc 15f )
143
144 11: stmfd sp!, {r5, r6, r8 - r10}
145
146 PLD( pld [r1, #-4] )
147 PLD( subs r2, r2, #96 )
148 PLD( pld [r1, #-32] )
149 PLD( blt 13f )
150 PLD( pld [r1, #-64] )
151 PLD( pld [r1, #-96] )
152
153 12: PLD( pld [r1, #-128] )
154 13: ldmdb r1!, {r8, r9, r10, ip}
155 mov lr, r3, lspush #\push
156 subs r2, r2, #32
157 ldmdb r1!, {r3, r4, r5, r6}
158 orr lr, lr, ip, lspull #\pull
159 mov ip, ip, lspush #\push
160 orr ip, ip, r10, lspull #\pull
161 mov r10, r10, lspush #\push
162 orr r10, r10, r9, lspull #\pull
163 mov r9, r9, lspush #\push
164 orr r9, r9, r8, lspull #\pull
165 mov r8, r8, lspush #\push
166 orr r8, r8, r6, lspull #\pull
167 mov r6, r6, lspush #\push
168 orr r6, r6, r5, lspull #\pull
169 mov r5, r5, lspush #\push
170 orr r5, r5, r4, lspull #\pull
171 mov r4, r4, lspush #\push
172 orr r4, r4, r3, lspull #\pull
173 stmdb r0!, {r4 - r6, r8 - r10, ip, lr}
174 bge 12b
175 PLD( cmn r2, #96 )
176 PLD( bge 13b )
177
178 ldmfd sp!, {r5, r6, r8 - r10}
179
180 14: ands ip, r2, #28
181 beq 16f
182
183 15: mov lr, r3, lspush #\push
184 ldr r3, [r1, #-4]!
185 subs ip, ip, #4
186 orr lr, lr, r3, lspull #\pull
187 str lr, [r0, #-4]!
188 bgt 15b
189 CALGN( cmp r2, #0 )
190 CALGN( bge 11b )
191
192 16: add r1, r1, #(\pull / 8)
193 b 8b
194
195 .endm
196
197
198 backward_copy_shift push=8 pull=24
199
200 17: backward_copy_shift push=16 pull=16
201
202 18: backward_copy_shift push=24 pull=8
203
204 UNWIND( .fnend )
205 ENDPROC(memmove)
206 ENDPROC(__memmove)
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