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
|
/* Compare two strings for differences.
For SPARC v7.
Copyright (C) 1996-2019 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Jakub Jelinek <jj@ultra.linux.cz>.
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>
/* Normally, this uses ((xword - 0x01010101) & 0x80808080) test
to find out if any byte in xword could be zero. This is fast, but
also gives false alarm for any byte in range 0x81-0xff. It does
not matter for correctness, as if this test tells us there could
be some zero byte, we check it byte by byte, but if bytes with
high bits set are common in the strings, then this will give poor
performance. You can #define EIGHTBIT_NOT_RARE and the algorithm
will use one tick slower, but more precise test
((xword - 0x01010101) & (~xword) & 0x80808080),
which does not give any false alarms (but if some bits are set,
one cannot assume from it which bytes are zero and which are not).
It is yet to be measured, what is the correct default for glibc
in these days for an average user.
*/
.text
.align 4
ENTRY(strcmp)
andcc %o0, 3, %g0
be 13f
sethi %hi(0x80808080), %g1
ldub [%o0], %o4
add %o0, 1, %o0
ldub [%o1], %o5
cmp %o4, 0
add %o1, 1, %o1
be 2f
subcc %o4, %o5, %o4
bne 2f
andcc %o0, 3, %g0
be 4f
or %g1, %lo(0x80808080), %o3
ldub [%o0], %o4
add %o0, 1, %o0
ldub [%o1], %o5
cmp %o4, 0
add %o1, 1, %o1
be 2f
subcc %o4, %o5, %o4
bne 2f
andcc %o0, 3, %g0
be 5f
sethi %hi(0x01010101), %g1
ldub [%o0], %o4
add %o0, 1, %o0
ldub [%o1], %o5
cmp %o4, 0
add %o1, 1, %o1
be 2f
subcc %o4, %o5, %o4
bne 2f
andcc %o1, 3, %g2
bne 12f
or %g1, %lo(0x01010101), %o2
b 1f
ld [%o0], %o4
2: retl
mov %o4, %o0
13: or %g1, %lo(0x80808080), %o3
4: sethi %hi(0x01010101), %g1
5: andcc %o1, 3, %g2
bne 12f
or %g1, %lo(0x01010101), %o2
0: ld [%o0], %o4
1: ld [%o1], %o5
sub %o4, %o2, %g1
add %o0, 4, %o0
cmp %o4, %o5
#ifdef EIGHTBIT_NOT_RARE
andn %g1, %o4, %g1
#endif
bne 11f
andcc %g1, %o3, %g0
be 0b
add %o1, 4, %o1
srl %o4, 24, %g4
andcc %g4, 0xff, %g0
be 2f
srl %o4, 16, %g4
andcc %g4, 0xff, %g0
be 2f
srl %o4, 8, %g4
andcc %g4, 0xff, %g0
be 2f
andcc %o4, 0xff, %g0
bne,a 1b
ld [%o0], %o4
2: retl
clr %o0
11: srl %o4, 24, %g4
srl %o5, 24, %g5
andcc %g4, 0xff, %g0
be 3f
subcc %g4, %g5, %g4
bne 3f
srl %o5, 16, %g5
srl %o4, 16, %g4
andcc %g4, 0xff, %g0
be 3f
subcc %g4, %g5, %g4
bne 3f
srl %o5, 8, %g5
srl %o4, 8, %g4
andcc %g4, 0xff, %g0
be 3f
subcc %g4, %g5, %g4
bne 3f
subcc %o4, %o5, %o4
retl
mov %o4, %o0
3: retl
mov %g4, %o0
12: save %sp, -64, %sp
ld [%i0], %i4
sll %g2, 3, %g3
andn %i1, 3, %i1
mov 32, %l1
ld [%i1], %l2
mov -1, %g6
add %i1, 4, %i1
sub %l1, %g3, %l1
sll %g6, %g3, %g6
1: sll %l2, %g3, %g5
and %i4, %g6, %l3
sub %i4, %i2, %g1
#ifdef EIGHTBIT_NOT_RARE
andn %g1, %i4, %g1
#endif
andcc %g1, %i3, %g1
bne 3f
cmp %g5, %l3
bne 2f
add %i0, 4, %i0
ld [%i1], %l2
add %i1, 4, %i1
srl %l2, %l1, %l4
or %l4, %g5, %l4
cmp %l4, %i4
be,a 1b
ld [%i0], %i4
restore %l4, %g0, %o3
retl
sub %o4, %o3, %o0
2: sll %l2, %g3, %i2
srl %i4, %g3, %i3
srl %i2, %g3, %i2
restore
retl
sub %o3, %o2, %o0
3: srl %i4, 24, %g4
srl %g5, 24, %l6
andcc %g4, 0xff, %g0
be 4f
subcc %g4, %l6, %g4
bne 4f
cmp %g2, 3
be 6f
srl %i4, 16, %g4
srl %g5, 16, %l6
andcc %g4, 0xff, %g0
be 4f
subcc %g4, %l6, %g4
bne 4f
cmp %g2, 2
be 5f
srl %i4, 8, %g4
srl %g5, 8, %l6
andcc %g4, 0xff, %g0
be 4f
subcc %g4, %l6, %g4
bne 4f
add %i0, 4, %i0
ld [%i1], %l2
add %i1, 4, %i1
srl %l2, 24, %g5
andcc %i4, 0xff, %g4
be 4f
subcc %g4, %g5, %g4
be,a 1b
ld [%i0], %i4
4: jmpl %i7 + 8, %g0
restore %g4, %g0, %o0
5: ld [%i1], %l2
add %i1, 4, %i1
add %i0, 4, %i0
srl %l2, 24, %l6
andcc %g4, 0xff, %g4
be 4b
subcc %g4, %l6, %g4
bne 4b
srl %l2, 16, %l6
andcc %i4, 0xff, %g4
and %l6, 0xff, %l6
be 4b
subcc %g4, %l6, %g4
be,a 1b
ld [%i0], %i4
jmpl %i7 + 8, %g0
restore %g4, %g0, %o0
6: ld [%i1], %l2
add %i1, 4, %i1
add %i0, 4, %i0
srl %l2, 24, %l6
andcc %g4, 0xff, %g4
be 4b
subcc %g4, %l6, %g4
bne 4b
srl %l2, 16, %l6
srl %i4, 8, %g4
and %l6, 0xff, %l6
andcc %g4, 0xff, %g4
be 4b
subcc %g4, %l6, %g4
bne 4b
srl %l2, 8, %l6
andcc %i4, 0xff, %g4
and %l6, 0xff, %l6
be 4b
subcc %g4, %l6, %g4
be,a 1b
ld [%i0], %i4
jmpl %i7 + 8, %g0
restore %g4, %g0, %o0
END(strcmp)
libc_hidden_builtin_def (strcmp)
|
