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
|
/* Vector optimized 32/64 bit S/390 version of memrchr.
Copyright (C) 2015-2019 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 <ifunc-memrchr.h>
#if HAVE_MEMRCHR_Z13
# include "sysdep.h"
# include "asm-syntax.h"
.text
/* void *memrchr (const void *s, int c, size_t n)
Scans memory for character c backwards
and returns pointer to first c.
Register usage:
-r0=tmp
-r1=tmp
-r2=s
-r3=c
-r4=n
-r5=s in loop
-v16=part of s
-v17=index of found c
-v18=c replicated
-v20=permute pattern
*/
ENTRY(MEMRCHR_Z13)
.machine "z13"
.machinemode "zarch_nohighgprs"
# if !defined __s390x__
llgfr %r4,%r4
# endif /* !defined __s390x__ */
clgije %r4,0,.Lnot_found
vlvgb %v18,%r3,0 /* Generate vector which elements are all c.
If c > 255, c will be truncated. */
vrepb %v18,%v18,0
llcr %r3,%r3 /* char c_char = (char) c. */
/* check byte n - 1. */
llc %r0,-1(%r4,%r2)
slgfi %r4,1
clrje %r0,%r3,.Lfound_end
jh .Lnot_found /* Return NULL if n is now 0. */
larl %r1,.Lpermute_mask /* Load permute mask. */
vl %v20,0(%r1)
/* check byte n - 2. */
llc %r0,-1(%r4,%r2)
slgfi %r4,1
clrje %r0,%r3,.Lfound_end
jh .Lnot_found /* Return NULL if n is now 0. */
clgijhe %r4,64,.Lloop64 /* If n >= 64 -> loop64. */
.Llt64:
/* Process n < 64 bytes. */
clgijl %r4,16,.Llt16 /* Jump away if n < 16. */
aghi %r4,-16
vl %v16,0(%r4,%r2)
vfeebs %v17,%v16,%v18
jno .Lfound0
clgijl %r4,16,.Llt16
aghi %r4,-16
vl %v16,0(%r4,%r2)
vfeebs %v17,%v16,%v18
jno .Lfound0
clgijl %r4,16,.Llt16
aghi %r4,-16
vl %v16,0(%r4,%r2)
vfeebs %v17,%v16,%v18
jno .Lfound0
.Llt16:
clgfi %r4,0 /* if remaining bytes == 0, return NULL. */
locghie %r2,0
ber %r14
aghi %r4,-1 /* vll needs highest index. */
vll %v16,%r4,0(%r2) /* Load remaining bytes. */
/* Right-shift of v16 to mask bytes after highest index. */
lhi %r0,15
slr %r0,%r4 /* Compute byte count for vector shift right. */
sll %r0,3 /* Convert to bit count. */
vlvgb %v17,%r0,7
vsrlb %v16,%v16,%v17 /* Vector shift right by byte by number of bytes
specified in bits 1-4 of byte 7 in v17. */
j .Lfound_permute
.Lfound48:
aghi %r4,16
.Lfound32:
aghi %r4,16
.Lfound16:
aghi %r4,16
.Lfound0:
la %r2,0(%r4,%r2) /* Set pointer to start of v16. */
lghi %r4,15 /* Set highest index in v16 to last index. */
.Lfound_permute:
/* Search for a c in v16 in reversed byte order. v16 contains %r4 + 1
bytes. If v16 was not fully loaded, the bytes are already
right shifted, so that the bytes in v16 can simply be reversed. */
vperm %v16,%v16,%v16,%v20 /* Permute v16 to reversed order. */
vfeeb %v16,%v16,%v18 /* Find c in reversed v16. */
vlgvb %r1,%v16,7 /* Index of c or 16 if not found. */
/* Return NULL if there is no c in loaded bytes. */
clrjh %r1,%r4,.Lnot_found
slgr %r4,%r1
.Lfound_end:
la %r2,0(%r4,%r2) /* Return pointer to c. */
br %r14
.Lnot_found:
lghi %r2,0
br %r14
.Lpermute_mask:
.byte 0x0F,0x0E,0x0D,0x0C,0x0B,0x0A,0x09,0x08
.byte 0x07,0x06,0x05,0x04,0x03,0x02,0x01,0x00
.Lloop64:
aghi %r4,-64
vl %v16,48(%r4,%r2) /* Load 16bytes of memory area. */
vfeebs %v17,%v16,%v18 /* Find c. */
jno .Lfound48 /* Jump away if c was found. */
vl %v16,32(%r4,%r2)
vfeebs %v17,%v16,%v18
jno .Lfound32
vl %v16,16(%r4,%r2)
vfeebs %v17,%v16,%v18
jno .Lfound16
vl %v16,0(%r4,%r2)
vfeebs %v17,%v16,%v18
jno .Lfound0
clgijhe %r4,64,.Lloop64 /* If n >= 64 -> loop64. */
j .Llt64
END(MEMRCHR_Z13)
# if ! HAVE_MEMRCHR_IFUNC
strong_alias (MEMRCHR_Z13, __memrchr)
weak_alias (__memrchr, memrchr)
# endif
#endif /* HAVE_MEMRCHR_Z13 */
|
