xref: /openbmc/linux/arch/arm/lib/memmove.S (revision 384740dc) 
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:		nop
78		ldr	r3, [r1, #-4]!
79		ldr	r4, [r1, #-4]!
80		ldr	r5, [r1, #-4]!
81		ldr	r6, [r1, #-4]!
82		ldr	r7, [r1, #-4]!
83		ldr	r8, [r1, #-4]!
84		ldr	lr, [r1, #-4]!
85
86		add	pc, pc, ip
87		nop
88		nop
89		str	r3, [r0, #-4]!
90		str	r4, [r0, #-4]!
91		str	r5, [r0, #-4]!
92		str	r6, [r0, #-4]!
93		str	r7, [r0, #-4]!
94		str	r8, [r0, #-4]!
95		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, push #\push
151		subs    r2, r2, #32
152		ldmdb   r1!, {r3, r4, r5, r6}
153		orr     lr, lr, ip, pull #\pull
154		mov     ip, ip, push #\push
155		orr     ip, ip, r9, pull #\pull
156		mov     r9, r9, push #\push
157		orr     r9, r9, r8, pull #\pull
158		mov     r8, r8, push #\push
159		orr     r8, r8, r7, pull #\pull
160		mov     r7, r7, push #\push
161		orr     r7, r7, r6, pull #\pull
162		mov     r6, r6, push #\push
163		orr     r6, r6, r5, pull #\pull
164		mov     r5, r5, push #\push
165		orr     r5, r5, r4, pull #\pull
166		mov     r4, r4, push #\push
167		orr     r4, r4, r3, pull #\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, push #\push
179		ldr	r3, [r1, #-4]!
180		subs	ip, ip, #4
181		orr	lr, lr, r3, pull #\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
199