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
|
/* Compare two strings for differences.
For SPARC v9.
Copyright (C) 2011-2014 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by David S. Miller <davem@davemloft.net>
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>
#include <asm/asi.h>
#ifndef XCC
.register %g2, #scratch
.register %g3, #scratch
.register %g6, #scratch
#endif
#define rSTR1 %o0
#define rSTR2 %o1
#define r0101 %o2 /* 0x0101010101010101 */
#define r8080 %o3 /* 0x8080808080808080 */
#define rSTRXOR %o4
#define rWORD1 %o5
#define rTMP1 %g1
#define rTMP2 %g2
#define rWORD2 %g3
#define rSLL %g4
#define rSRL %g5
#define rBARREL %g6
/* There are two cases, either the two pointers are aligned
* identically or they are not. If they have the same
* alignment we can use the normal full speed loop. Otherwise
* we have to use the barrel-shifter version.
*/
.text
.align 32
ENTRY(strcmp)
or rSTR2, rSTR1, rTMP1
sethi %hi(0x80808080), r8080
andcc rTMP1, 0x7, %g0
bne,pn %icc, .Lmaybe_barrel_shift
or r8080, %lo(0x80808080), r8080
ldx [rSTR1], rWORD1
sub rSTR2, rSTR1, rSTR2
sllx r8080, 32, rTMP1
ldx [rSTR1 + rSTR2], rWORD2
or r8080, rTMP1, r8080
ba,pt %xcc, .Laligned_loop_entry
srlx r8080, 7, r0101
.align 32
.Laligned_loop_entry:
.Laligned_loop:
add rSTR1, 8, rSTR1
sub rWORD1, r0101, rTMP2
xorcc rWORD1, rWORD2, rSTRXOR
bne,pn %xcc, .Lcommon_endstring
andn r8080, rWORD1, rTMP1
ldxa [rSTR1] ASI_PNF, rWORD1
andcc rTMP1, rTMP2, %g0
be,a,pt %xcc, .Laligned_loop
ldxa [rSTR1 + rSTR2] ASI_PNF, rWORD2
.Lcommon_equal:
retl
mov 0, %o0
/* All loops terminate here once they find an unequal word.
* If a zero byte appears in the word before the first unequal
* byte, we must report zero. Otherwise we report '1' or '-1'
* depending upon whether the first mis-matching byte is larger
* in the first string or the second, respectively.
*
* First we compute a 64-bit mask value that has "0x01" in
* each byte where a zero exists in rWORD1. rSTRXOR holds the
* value (rWORD1 ^ rWORD2). Therefore, if considered as an
* unsigned quantity, our "0x01" mask value is "greater than"
* rSTRXOR then a zero terminating byte comes first and
* therefore we report '0'.
*
* The formula for this mask is:
*
* mask_tmp1 = ~rWORD1 & 0x8080808080808080;
* mask_tmp2 = ((rWORD1 & 0x7f7f7f7f7f7f7f7f) +
* 0x7f7f7f7f7f7f7f7f);
*
* mask = ((mask_tmp1 & ~mask_tmp2) >> 7);
*/
.Lcommon_endstring:
andn rWORD1, r8080, rTMP2
or r8080, 1, %o1
mov 1, %o0
sub rTMP2, %o1, rTMP2
cmp rWORD1, rWORD2
andn rTMP1, rTMP2, rTMP1
movleu %xcc, -1, %o0
srlx rTMP1, 7, rTMP1
/* In order not to be influenced by bytes after the zero byte, we
* have to retain only the highest bit in the mask for the comparison
* with rSTRXOR to work properly.
*/
mov 0, rTMP2
andcc rTMP1, 0x0100, %g0
movne %xcc, 8, rTMP2
sllx rTMP1, 63 - 16, %o1
movrlz %o1, 16, rTMP2
sllx rTMP1, 63 - 24, %o1
movrlz %o1, 24, rTMP2
sllx rTMP1, 63 - 32, %o1
movrlz %o1, 32, rTMP2
sllx rTMP1, 63 - 40, %o1
movrlz %o1, 40, rTMP2
sllx rTMP1, 63 - 48, %o1
movrlz %o1, 48, rTMP2
sllx rTMP1, 63 - 56, %o1
movrlz %o1, 56, rTMP2
srlx rTMP1, rTMP2, rTMP1
sllx rTMP1, rTMP2, rTMP1
cmp rTMP1, rSTRXOR
retl
movgu %xcc, 0, %o0
.Lmaybe_barrel_shift:
sub rSTR2, rSTR1, rSTR2
sllx r8080, 32, rTMP1
or r8080, rTMP1, r8080
and rSTR1, 0x7, rTMP2
srlx r8080, 7, r0101
andn rSTR1, 0x7, rSTR1
ldxa [rSTR1] ASI_PNF, rWORD1
andcc rSTR2, 0x7, rSLL
sll rTMP2, 3, rSTRXOR
bne,pn %icc, .Lneed_barrel_shift
mov -1, rTMP1
ldxa [rSTR1 + rSTR2] ASI_PNF, rBARREL
srlx rTMP1, rSTRXOR, rTMP2
orn rWORD1, rTMP2, rWORD1
ba,pt %xcc, .Laligned_loop_entry
orn rBARREL, rTMP2, rWORD2
.Lneed_barrel_shift:
sllx rSLL, 3, rSLL
andn rSTR2, 0x7, rSTR2
ldxa [rSTR1 + rSTR2] ASI_PNF, rBARREL
mov 64, rTMP2
sub rTMP2, rSLL, rSRL
srlx rTMP1, rSTRXOR, rTMP1
add rSTR2, 8, rSTR2
orn rWORD1, rTMP1, rWORD1
sllx rBARREL, rSLL, rWORD2
ldxa [rSTR1 + rSTR2] ASI_PNF, rBARREL
add rSTR1, 8, rSTR1
sub rWORD1, r0101, rTMP2
srlx rBARREL, rSRL, rSTRXOR
or rWORD2, rSTRXOR, rWORD2
orn rWORD2, rTMP1, rWORD2
ba,pt %xcc, .Lbarrel_shift_loop_entry
andn r8080, rWORD1, rTMP1
.Lbarrel_shift_loop:
sllx rBARREL, rSLL, rWORD2
ldxa [rSTR1 + rSTR2] ASI_PNF, rBARREL
add rSTR1, 8, rSTR1
sub rWORD1, r0101, rTMP2
srlx rBARREL, rSRL, rSTRXOR
andn r8080, rWORD1, rTMP1
or rWORD2, rSTRXOR, rWORD2
.Lbarrel_shift_loop_entry:
xorcc rWORD1, rWORD2, rSTRXOR
bne,pn %xcc, .Lcommon_endstring
andcc rTMP1, rTMP2, %g0
be,a,pt %xcc, .Lbarrel_shift_loop
ldxa [rSTR1] ASI_PNF, rWORD1
retl
mov 0, %o0
END(strcmp)
libc_hidden_builtin_def (strcmp)
|
