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
|
/* Determine the length of a string. For SPARC v9.
Copyright (C) 1998, 1999 Free Software Foundation, Inc.
Contributed by Jan Vondrak <jvon4518@ss1000.ms.mff.cuni.cz> and
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 Library General Public License as
published by the Free Software Foundation; either version 2 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If not,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#include <sysdep.h>
#include <asm/asi.h>
/* Normally, this uses
((xword - 0x0101010101010101) & 0x8080808080808080) 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 - 0x0101010101010101) & (~xword) & 0x8080808080808080),
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 32
ENTRY(strlen)
sethi %hi(0x01010101), %g1 /* IEU0 Group */
ldub [%o0], %o3 /* Load */
or %g1, %lo(0x01010101), %g1 /* IEU0 Group */
mov %o0, %o1 /* IEU1 */
sllx %g1, 32, %g2 /* IEU0 Group */
andcc %o0, 7, %g0 /* IEU1 */
or %g1, %g2, %g1 /* IEU0 Group */
brz,pn %o3, 13f /* CTI+IEU1 */
sllx %g1, 7, %g2 /* IEU0 Group */
bne,a,pn %icc, 15f /* CTI */
add %o0, 1, %o0 /* IEU1 */
/* %g1 = 0x0101010101010101 *
* %g2 = 0x8080808080808080 *
* %o0 = string pointer *
* %o1 = start of string */
1: ldx [%o0], %o3 /* Load Group */
add %o0, 8, %o0 /* IEU1 */
2: sub %o3, %g1, %o2 /* IEU0 Group */
#ifdef EIGHTBIT_NOT_RARE
andn %o2, %o3, %g7 /* IEU0 Group */
ldxa [%o0] ASI_PNF, %o3 /* Load */
andcc %g7, %g2, %g0 /* IEU1 Group */
#else
ldxa [%o0] ASI_PNF, %o3 /* Load */
andcc %o2, %g2, %g0 /* IEU1 Group */
#endif
be,pt %xcc, 2b /* CTI */
add %o0, 8, %o0 /* IEU0 */
addcc %o2, %g1, %g3 /* IEU1 Group */
#ifdef EIGHTBIT_NOT_RARE
srlx %g7, 32, %g7 /* IEU0 */
3: andcc %g7, %g2, %g0 /* IEU1 Group */
#else
srlx %o2, 32, %o2 /* IEU0 */
3: andcc %o2, %g2, %g0 /* IEU1 Group */
#endif
be,pn %xcc, 4f /* CTI */
srlx %g3, 56, %o2 /* IEU0 */
andcc %o2, 0xff, %g0 /* IEU1 Group */
be,pn %icc, 12f /* CTI */
srlx %g3, 48, %o2 /* IEU0 */
andcc %o2, 0xff, %g0 /* IEU1 Group */
be,pn %icc, 11f /* CTI */
srlx %g3, 40, %o2 /* IEU0 */
andcc %o2, 0xff, %g0 /* IEU1 Group */
be,pn %icc, 10f /* CTI */
srlx %g3, 32, %o2 /* IEU0 */
andcc %o2, 0xff, %g0 /* IEU1 Group */
be,pn %icc, 9f /* CTI */
4: srlx %g3, 24, %o2 /* IEU0 */
andcc %o2, 0xff, %g0 /* IEU1 Group */
be,pn %icc, 8f /* CTI */
srlx %g3, 16, %o2 /* IEU0 */
andcc %o2, 0xff, %g0 /* IEU1 Group */
be,pn %icc, 7f /* CTI */
srlx %g3, 8, %o2 /* IEU0 */
andcc %o2, 0xff, %g0 /* IEU1 Group */
be,pn %icc, 6f /* CTI */
sub %o3, %g1, %o2 /* IEU0 */
andcc %g3, 0xff, %g0 /* IEU1 Group */
be,pn %icc, 5f /* CTI */
ldxa [%o0] ASI_PNF, %o3 /* Load */
andcc %o2, %g2, %g0 /* IEU1 Group */
be,pt %xcc, 2b /* CTI */
add %o0, 8, %o0 /* IEU0 */
addcc %o2, %g1, %g3 /* IEU1 Group */
ba,pt %xcc, 3b /* CTI */
srlx %o2, 32, %o2 /* IEU0 */
5: add %o0, -9, %o0 /* IEU0 Group */
retl /* CTI+IEU1 Group */
sub %o0, %o1, %o0 /* IEU0 */
6: add %o0, -10, %o0 /* IEU0 Group */
retl /* CTI+IEU1 Group */
sub %o0, %o1, %o0 /* IEU0 */
7: add %o0, -11, %o0 /* IEU0 Group */
retl /* CTI+IEU1 Group */
sub %o0, %o1, %o0 /* IEU0 */
8: add %o0, -12, %o0 /* IEU0 Group */
retl /* CTI+IEU1 Group */
sub %o0, %o1, %o0 /* IEU0 */
9: add %o0, -13, %o0 /* IEU0 Group */
retl /* CTI+IEU1 Group */
sub %o0, %o1, %o0 /* IEU0 */
10: add %o0, -14, %o0 /* IEU0 Group */
retl /* CTI+IEU1 Group */
sub %o0, %o1, %o0 /* IEU0 */
11: add %o0, -15, %o0 /* IEU0 Group */
retl /* CTI+IEU1 Group */
sub %o0, %o1, %o0 /* IEU0 */
12: add %o0, -16, %o0 /* IEU0 Group */
retl /* CTI+IEU1 Group */
sub %o0, %o1, %o0 /* IEU0 */
13: retl /* CTI+IEU1 Group */
mov 0, %o0 /* IEU0 */
nop
15: ldub [%o0], %o3 /* Load Group */
16: andcc %o0, 7, %g0 /* IEU1 */
be,pn %icc, 1b /* CTI */
nop /* IEU0 Group */
add %o0, 1, %o0 /* IEU1 */
andcc %o3, 0xff, %g0 /* IEU1 Group */
bne,a,pt %icc, 16b /* CTI */
lduba [%o0] ASI_PNF, %o3 /* Load */
add %o0, -1, %o0 /* IEU0 Group */
retl /* CTI+IEU1 Group */
sub %o0, %o1, %o0 /* IEU0 */
END(strlen)
|
