aboutsummaryrefslogtreecommitdiff
path: root/sysdeps/sh/memcpy.S
blob: 7a877d6ea8a9eb1d97de2382d4f51ca528af5a84 (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
/* Copyright (C) 1999-2024 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <https://www.gnu.org/licenses/>.  */

#include <sysdep.h>

/* void *memcpy(void *dst, const void *src, size_t n);
    No overlap between the memory of DST and of SRC are assumed.  */

ENTRY(memcpy)
	mov	r4,r3		/* Save destination.  */

	/* If less than 11 bytes, just do a byte copy.  */
	mov	#11,r0
	cmp/gt	r6,r0
	bt	L_byteloop_init

	/* Check if we need to word-align source.  */
	mov	r5,r0
	tst	#1,r0
	bt	L_wordalign

	mov.b	@r0+,r1		/* Copy one byte.  */
	add	#-1,r6
	mov.b	r1,@r4
	add	#1,r4

	.balignw 4,0x0009
L_wordalign:
	/* Check if we need to longword-align source.  */
	tst	#2,r0
	bt	L_copy

	mov.w	@r0+,r1		/* Copy one word.  */
	add	#-2,r6
#ifdef __BIG_ENDIAN__
	add	#1,r4
	mov.b	r1,@r4
	shlr8	r1
	mov.b	r1,@-r4
	add	#2,r4
#else
	mov.b	r1,@r4
	add	#1,r4
	shlr8	r1
	mov.b	r1,@r4
	add	#1,r4
#endif
L_copy:
	mov	r0,r5

	/* Calculate the correct routine to handle the destination
	   alignment and simultaneously calculate the loop counts for
	   both the 2 word copy loop and byte copy loop.  */
	mova	L_jumptable,r0
	mov	r0,r1
	mov	r4,r0
	mov	r6,r7
	and	#3,r0
	shlr2	r7
	shll	r0
	shlr	r7
	mov.w	@(r0,r1),r2
	mov	#7,r0
	braf	r2
	and	r0,r6
L_base:

	.balign	4
L_jumptable:
	.word	L_copydest0 - L_base
	.word	L_copydest1_or_3 - L_base
	.word	L_copydest2 - L_base
	.word	L_copydest1_or_3 - L_base

	.balign	4
	/* Copy routine for (dest mod 4) == 1 or == 3.  */
L_copydest1_or_3:
	add	#-1,r4
	.balignw 4,0x0009
L_copydest1_or_3_loop:
	mov.l	@r5+,r0		/* Read first longword.  */
	dt	r7
	mov.l	@r5+,r1		/* Read second longword.  */
#ifdef __BIG_ENDIAN__
	/* Write first longword as byte, word, byte.  */
	mov.b	r0,@(4,r4)
	shlr8	r0
	mov.w	r0,@(2,r4)
	shlr16	r0
	mov.b	r0,@(1,r4)
	mov	r1,r0
	/* Write second longword as byte, word, byte.  */
	mov.b	r0,@(8,r4)
	shlr8	r0
	mov.w	r0,@(6,r4)
	shlr16	r0
	mov.b	r0,@(5,r4)
#else
	/* Write first longword as byte, word, byte.  */
	mov.b	r0,@(1,r4)
	shlr8	r0
	mov.w	r0,@(2,r4)
	shlr16	r0
	mov.b	r0,@(4,r4)
	mov	r1,r0
	/* Write second longword as byte, word, byte.  */
	mov.b	r0,@(5,r4)
	shlr8	r0
	mov.w	r0,@(6,r4)
	shlr16	r0
	mov.b	r0,@(8,r4)
#endif
	bf/s	L_copydest1_or_3_loop
	add	#8,r4

	bra	L_byteloop_init
	add	#1,r4

	.balign 4
	/* Copy routine for (dest mod 4) == 2.  */
L_copydest2:
L_copydest2_loop:
	mov.l	@r5+,r0
	dt	r7
	mov.l	@r5+,r1
#ifdef __BIG_ENDIAN__
	mov.w	r0,@(2,r4)
	shlr16	r0
	mov.w	r0,@r4
	mov	r1,r0
	mov.w	r0,@(6,r4)
	shlr16	r0
	mov.w	r0,@(4,r4)
#else
	mov.w	r0,@r4
	shlr16	r0
	mov.w	r0,@(2,r4)
	mov	r1,r0
	mov.w	r0,@(4,r4)
	shlr16	r0
	mov.w	r0,@(6,r4)
#endif
	bf/s	L_copydest2_loop
	add	#8,r4

	bra	L_byteloop_init
	nop

	.balign 4
	/* Copy routine for (dest mod 4) == 0.  */
L_copydest0:
	add	#-8,r4
	.balignw 4,0x0009
L_copydest0_loop:
	mov.l	@r5+,r0
	dt	r7
	mov.l	@r5+,r1
	add	#8,r4
	mov.l	r0,@r4
	bf/s	L_copydest0_loop
	mov.l	r1,@(4,r4)

	add	#8,r4		/* Fall through.  */

L_byteloop_init:
	tst	r6,r6
	bt	L_exit

	.balignw 4,0x0009
	/* Copy remaining bytes.  */
L_byteloop:
	mov.b	@r5+,r0
	dt	r6
	mov.b	r0,@r4
	bf/s	L_byteloop
	add	#1,r4

L_exit:
	rts
	mov	r3,r0		/* Return destination.  */
END(memcpy)
libc_hidden_builtin_def (memcpy)