aboutsummaryrefslogtreecommitdiff
path: root/arch/arm/lib/memcpy.S
blob: f7fb77235cd642b734fdb17c60f0a4e1b2c9cd64 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
/* SPDX-License-Identifier: GPL-2.0 */
/*
 *  linux/arch/arm/lib/memcpy.S
 *
 *  Author:	Nicolas Pitre
 *  Created:	Sep 28, 2005
 *  Copyright:	MontaVista Software, Inc.
 */

#include <linux/linkage.h>
#include <asm/assembler.h>

#define LDR1W_SHIFT	0
#define STR1W_SHIFT	0

	.macro ldr1w ptr reg abort
	W(ldr) \reg, [\ptr], #4
	.endm

	.macro ldr4w ptr reg1 reg2 reg3 reg4 abort
	ldmia \ptr!, {\reg1, \reg2, \reg3, \reg4}
	.endm

	.macro ldr8w ptr reg1 reg2 reg3 reg4 reg5 reg6 reg7 reg8 abort
	ldmia \ptr!, {\reg1, \reg2, \reg3, \reg4, \reg5, \reg6, \reg7, \reg8}
	.endm

	.macro ldr1b ptr reg cond=al abort
	ldrb\cond\() \reg, [\ptr], #1
	.endm

	.macro str1w ptr reg abort
	W(str) \reg, [\ptr], #4
	.endm

	.macro str8w ptr reg1 reg2 reg3 reg4 reg5 reg6 reg7 reg8 abort
	stmia \ptr!, {\reg1, \reg2, \reg3, \reg4, \reg5, \reg6, \reg7, \reg8}
	.endm

	.macro str1b ptr reg cond=al abort
	strb\cond\() \reg, [\ptr], #1
	.endm

	.macro enter reg1 reg2
	stmdb sp!, {r0, \reg1, \reg2}
	.endm

	.macro exit reg1 reg2
	ldmfd sp!, {r0, \reg1, \reg2}
	.endm

	.text

/* Prototype: void *memcpy(void *dest, const void *src, size_t n); */
	.syntax unified
#if CONFIG_IS_ENABLED(SYS_THUMB_BUILD) && !defined(MEMCPY_NO_THUMB_BUILD)
	.thumb
	.thumb_func
#endif
ENTRY(memcpy)
		cmp	r0, r1
		bxeq	lr

		enter	r4, lr

		subs	r2, r2, #4
		blt	8f
		ands	ip, r0, #3
	PLD(	pld	[r1, #0]		)
		bne	9f
		ands	ip, r1, #3
		bne	10f

1:		subs	r2, r2, #(28)
		stmfd	sp!, {r5 - r8}
		blt	5f

	CALGN(	ands	ip, r0, #31		)
	CALGN(	rsb	r3, ip, #32		)
	CALGN(	sbcsne	r4, r3, r2		)  @ C is always set here
	CALGN(	bcs	2f			)
	CALGN(	adr	r4, 6f			)
	CALGN(	subs	r2, r2, r3		)  @ C gets set
	CALGN(	add	pc, r4, ip		)

	PLD(	pld	[r1, #0]		)
2:	PLD(	subs	r2, r2, #96		)
	PLD(	pld	[r1, #28]		)
	PLD(	blt	4f			)
	PLD(	pld	[r1, #60]		)
	PLD(	pld	[r1, #92]		)

3:	PLD(	pld	[r1, #124]		)
4:		ldr8w	r1, r3, r4, r5, r6, r7, r8, ip, lr, abort=20f
		subs	r2, r2, #32
		str8w	r0, r3, r4, r5, r6, r7, r8, ip, lr, abort=20f
		bge	3b
	PLD(	cmn	r2, #96			)
	PLD(	bge	4b			)

5:		ands	ip, r2, #28
		rsb	ip, ip, #32
#if LDR1W_SHIFT > 0
		lsl	ip, ip, #LDR1W_SHIFT
#endif
		addne	pc, pc, ip		@ C is always clear here
		b	7f
6:
		.rept	(1 << LDR1W_SHIFT)
		W(nop)
		.endr
		ldr1w	r1, r3, abort=20f
		ldr1w	r1, r4, abort=20f
		ldr1w	r1, r5, abort=20f
		ldr1w	r1, r6, abort=20f
		ldr1w	r1, r7, abort=20f
		ldr1w	r1, r8, abort=20f
		ldr1w	r1, lr, abort=20f

#if LDR1W_SHIFT < STR1W_SHIFT
		lsl	ip, ip, #STR1W_SHIFT - LDR1W_SHIFT
#elif LDR1W_SHIFT > STR1W_SHIFT
		lsr	ip, ip, #LDR1W_SHIFT - STR1W_SHIFT
#endif
		add	pc, pc, ip
		nop
		.rept	(1 << STR1W_SHIFT)
		W(nop)
		.endr
		str1w	r0, r3, abort=20f
		str1w	r0, r4, abort=20f
		str1w	r0, r5, abort=20f
		str1w	r0, r6, abort=20f
		str1w	r0, r7, abort=20f
		str1w	r0, r8, abort=20f
		str1w	r0, lr, abort=20f

	CALGN(	bcs	2b			)

7:		ldmfd	sp!, {r5 - r8}

8:		movs	r2, r2, lsl #31
		ldr1b	r1, r3, ne, abort=21f
		ldr1b	r1, r4, cs, abort=21f
		ldr1b	r1, ip, cs, abort=21f
		str1b	r0, r3, ne, abort=21f
		str1b	r0, r4, cs, abort=21f
		str1b	r0, ip, cs, abort=21f

		exit	r4, lr
		bx	lr

9:		rsb	ip, ip, #4
		cmp	ip, #2
		ldr1b	r1, r3, gt, abort=21f
		ldr1b	r1, r4, ge, abort=21f
		ldr1b	r1, lr, abort=21f
		str1b	r0, r3, gt, abort=21f
		str1b	r0, r4, ge, abort=21f
		subs	r2, r2, ip
		str1b	r0, lr, abort=21f
		blt	8b
		ands	ip, r1, #3
		beq	1b

10:		bic	r1, r1, #3
		cmp	ip, #2
		ldr1w	r1, lr, abort=21f
		beq	17f
		bgt	18f


		.macro	forward_copy_shift pull push

		subs	r2, r2, #28
		blt	14f

	CALGN(	ands	ip, r0, #31		)
	CALGN(	rsb	ip, ip, #32		)
	CALGN(	sbcsne	r4, ip, r2		)  @ C is always set here
	CALGN(	subcc	r2, r2, ip		)
	CALGN(	bcc	15f			)

11:		stmfd	sp!, {r5 - r9}

	PLD(	pld	[r1, #0]		)
	PLD(	subs	r2, r2, #96		)
	PLD(	pld	[r1, #28]		)
	PLD(	blt	13f			)
	PLD(	pld	[r1, #60]		)
	PLD(	pld	[r1, #92]		)

12:	PLD(	pld	[r1, #124]		)
13:		ldr4w	r1, r4, r5, r6, r7, abort=19f
		mov	r3, lr, lspull #\pull
		subs	r2, r2, #32
		ldr4w	r1, r8, r9, ip, lr, abort=19f
		orr	r3, r3, r4, lspush #\push
		mov	r4, r4, lspull #\pull
		orr	r4, r4, r5, lspush #\push
		mov	r5, r5, lspull #\pull
		orr	r5, r5, r6, lspush #\push
		mov	r6, r6, lspull #\pull
		orr	r6, r6, r7, lspush #\push
		mov	r7, r7, lspull #\pull
		orr	r7, r7, r8, lspush #\push
		mov	r8, r8, lspull #\pull
		orr	r8, r8, r9, lspush #\push
		mov	r9, r9, lspull #\pull
		orr	r9, r9, ip, lspush #\push
		mov	ip, ip, lspull #\pull
		orr	ip, ip, lr, lspush #\push
		str8w	r0, r3, r4, r5, r6, r7, r8, r9, ip, , abort=19f
		bge	12b
	PLD(	cmn	r2, #96			)
	PLD(	bge	13b			)

		ldmfd	sp!, {r5 - r9}

14:		ands	ip, r2, #28
		beq	16f

15:		mov	r3, lr, lspull #\pull
		ldr1w	r1, lr, abort=21f
		subs	ip, ip, #4
		orr	r3, r3, lr, lspush #\push
		str1w	r0, r3, abort=21f
		bgt	15b
	CALGN(	cmp	r2, #0			)
	CALGN(	bge	11b			)

16:		sub	r1, r1, #(\push / 8)
		b	8b

		.endm


		forward_copy_shift	pull=8	push=24

17:		forward_copy_shift	pull=16	push=16

18:		forward_copy_shift	pull=24	push=8


/*
 * Abort preamble and completion macros.
 * If a fixup handler is required then those macros must surround it.
 * It is assumed that the fixup code will handle the private part of
 * the exit macro.
 */

	.macro	copy_abort_preamble
19:	ldmfd	sp!, {r5 - r9}
	b	21f
20:	ldmfd	sp!, {r5 - r8}
21:
	.endm

	.macro	copy_abort_end
	ldmfd	sp!, {r4, lr}
	bx	lr
	.endm

ENDPROC(memcpy)