aboutsummaryrefslogtreecommitdiff
path: root/sysdeps/powerpc/powerpc64/strcpy.S
blob: 793325d7bef0f5b5653fb266260bcc6a2fb8d58a (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
/* Optimized strcpy implementation for PowerPC64.
   Copyright (C) 1997-2013 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
   <http://www.gnu.org/licenses/>.  */

#include <sysdep.h>

/* See strlen.s for comments on how the end-of-string testing works.  */

/* char * [r3] strcpy (char *dest [r3], const char *src [r4])  */

#ifdef USE_AS_STPCPY
# define FUNC_NAME __stpcpy
#else
# define FUNC_NAME strcpy
#endif

EALIGN (FUNC_NAME, 4, 0)
	CALL_MCOUNT 2

#define rTMP	r0
#ifdef USE_AS_STPCPY
#define rRTN    r3      /* pointer to previous word/doubleword in dest */
#else
#define rRTN    r12     /* pointer to previous word/doubleword in dest */
#endif
#define rSRC	r4	/* pointer to previous word/doubleword in src */
#define rWORD	r6	/* current word from src */
#define rFEFE	r7	/* constant 0xfefefeff | 0xfefefefefefefeff */
#define r7F7F	r8	/* constant 0x7f7f7f7f | 0x7f7f7f7f7f7f7f7f */
#define rNEG	r9	/* ~(word in s1 | r7F7F) */
#define rALT	r10	/* alternate word from src */

#ifndef USE_AS_STPCPY
/* Save the dst pointer to use as return value.  */
	mr      rRTN, r3
#endif
	or	rTMP, rSRC, rRTN
	clrldi.	rTMP, rTMP, 61
	bne	L(check_word_alignment)

/* For doubleword aligned memory, operate using doubleword load and stores.  */
	addi	rRTN, rRTN, -8

	lis	rFEFE, -0x101
	lis	r7F7F, 0x7f7f
	ld	rWORD, 0(rSRC)
	addi	rFEFE, rFEFE, -0x101
	addi	r7F7F, r7F7F, 0x7f7f
	sldi	rTMP, rFEFE, 32
	insrdi	r7F7F, r7F7F, 32, 0
	add	rFEFE, rFEFE, rTMP
	b	L(g2)

L(g0):	ldu	rALT, 8(rSRC)
	stdu	rWORD, 8(rRTN)
	add	rTMP, rFEFE, rALT
	nor	rNEG, r7F7F, rALT
	and.	rTMP, rTMP, rNEG
	bne-	L(g1)
	ldu	rWORD, 8(rSRC)
	stdu	rALT, 8(rRTN)
L(g2):	add	rTMP, rFEFE, rWORD
	nor	rNEG, r7F7F, rWORD
	and.	rTMP, rTMP, rNEG
	beq+	L(g0)

	mr	rALT, rWORD
/* We've hit the end of the string.  Do the rest byte-by-byte.  */
L(g1):
#ifdef __LITTLE_ENDIAN__
	extrdi.	rTMP, rALT, 8, 56
	stbu	rALT, 8(rRTN)
	beqlr-
	extrdi.	rTMP, rALT, 8, 48
	stbu	rTMP, 1(rRTN)
	beqlr-
	extrdi.	rTMP, rALT, 8, 40
	stbu	rTMP, 1(rRTN)
	beqlr-
	extrdi.	rTMP, rALT, 8, 32
	stbu	rTMP, 1(rRTN)
	beqlr-
	extrdi.	rTMP, rALT, 8, 24
	stbu	rTMP, 1(rRTN)
	beqlr-
	extrdi.	rTMP, rALT, 8, 16
	stbu	rTMP, 1(rRTN)
	beqlr-
	extrdi.	rTMP, rALT, 8, 8
	stbu	rTMP, 1(rRTN)
	beqlr-
	extrdi	rTMP, rALT, 8, 0
	stbu	rTMP, 1(rRTN)
#else
	extrdi.	rTMP, rALT, 8, 0
	stbu	rTMP, 8(rRTN)
	beqlr-
	extrdi.	rTMP, rALT, 8, 8
	stbu	rTMP, 1(rRTN)
	beqlr-
	extrdi.	rTMP, rALT, 8, 16
	stbu	rTMP, 1(rRTN)
	beqlr-
	extrdi.	rTMP, rALT, 8, 24
	stbu	rTMP, 1(rRTN)
	beqlr-
	extrdi.	rTMP, rALT, 8, 32
	stbu	rTMP, 1(rRTN)
	beqlr
	extrdi.	rTMP, rALT, 8, 40
	stbu	rTMP, 1(rRTN)
	beqlr-
	extrdi.	rTMP, rALT, 8, 48
	stbu	rTMP, 1(rRTN)
	beqlr-
	stbu	rALT, 1(rRTN)
#endif
	blr

L(check_word_alignment):
	clrldi. rTMP, rTMP, 62
	bne     L(unaligned)

/* For word aligned memory, operate using word load and stores.  */
	addi	rRTN, rRTN, -4

	lis	rFEFE, -0x101
	lis	r7F7F, 0x7f7f
	lwz	rWORD, 0(rSRC)
	addi	rFEFE, rFEFE, -0x101
	addi	r7F7F, r7F7F, 0x7f7f
	b	L(g5)

L(g3):	lwzu	rALT, 4(rSRC)
	stwu	rWORD, 4(rRTN)
	add	rTMP, rFEFE, rALT
	nor	rNEG, r7F7F, rALT
	and.	rTMP, rTMP, rNEG
	bne-	L(g4)
	lwzu	rWORD, 4(rSRC)
	stwu	rALT, 4(rRTN)
L(g5):	add	rTMP, rFEFE, rWORD
	nor	rNEG, r7F7F, rWORD
	and.	rTMP, rTMP, rNEG
	beq+	L(g3)

	mr	rALT, rWORD
/* We've hit the end of the string.  Do the rest byte-by-byte.  */
L(g4):
#ifdef __LITTLE_ENDIAN__
	rlwinm.	rTMP, rALT, 0, 24, 31
	stbu	rALT, 4(rRTN)
	beqlr-
	rlwinm.	rTMP, rALT, 24, 24, 31
	stbu	rTMP, 1(rRTN)
	beqlr-
	rlwinm.	rTMP, rALT, 16, 24, 31
	stbu	rTMP, 1(rRTN)
	beqlr-
	rlwinm	rTMP, rALT, 8, 24, 31
	stbu	rTMP, 1(rRTN)
#else
	rlwinm.	rTMP, rALT, 8, 24, 31
	stbu	rTMP, 4(rRTN)
	beqlr-
	rlwinm.	rTMP, rALT, 16, 24, 31
	stbu	rTMP, 1(rRTN)
	beqlr-
	rlwinm.	rTMP, rALT, 24, 24, 31
	stbu	rTMP, 1(rRTN)
	beqlr-
	stbu	rALT, 1(rRTN)
#endif
	blr

/* Oh well.  In this case, we just do a byte-by-byte copy.  */
	.align 4
	nop
L(unaligned):
	lbz	rWORD, 0(rSRC)
	addi	rRTN, rRTN, -1
	cmpwi	rWORD, 0
	beq-	L(u2)

L(u0):	lbzu	rALT, 1(rSRC)
	stbu	rWORD, 1(rRTN)
	cmpwi	rALT, 0
	beq-	L(u1)
	nop		/* Let 601 load start of loop.  */
	lbzu	rWORD, 1(rSRC)
	stbu	rALT, 1(rRTN)
	cmpwi	rWORD, 0
	bne+	L(u0)
L(u2):	stbu	rWORD, 1(rRTN)
	blr
L(u1):	stbu	rALT, 1(rRTN)
	blr
END (FUNC_NAME)

#ifndef USE_AS_STPCPY
libc_hidden_builtin_def (strcpy)
#endif