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
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
|
/* Placeholder function, not used by any processor at the moment.
Copyright (C) 2022-2023 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/>. */
/* UNUSED. Exists purely as reference implementation. */
#include <isa-level.h>
#if ISA_SHOULD_BUILD (4)
# include <sysdep.h>
# ifdef USE_AS_WCSCHR
# define CHAR_REG esi
# define CHAR_SIZE 4
# define VPBROADCAST vpbroadcastd
# define VPCMP vpcmpd
# define VPCMPNE vpcmpneqd
# define VPMINU vpminud
# define VPTEST vptestmd
# define VPTESTN vptestnmd
# else
# define CHAR_REG sil
# define CHAR_SIZE 1
# define VPBROADCAST vpbroadcastb
# define VPCMP vpcmpb
# define VPCMPNE vpcmpneqb
# define VPMINU vpminub
# define VPTEST vptestmb
# define VPTESTN vptestnmb
# endif
# define PAGE_SIZE 4096
# define CHAR_PER_VEC (VEC_SIZE / CHAR_SIZE)
# define VEC_MATCH_MASK ((1 << CHAR_PER_VEC) - 1)
.section SECTION(.text), "ax", @progbits
/* Aligning entry point to 64 byte, provides better performance for
one vector length string. */
ENTRY_P2ALIGN (STRCHR, 6)
/* Broadcast CHAR to VMM(0). */
VPBROADCAST %esi, %VMM(0)
movl %edi, %eax
sall $20,%eax
cmpl $((PAGE_SIZE - VEC_SIZE) << 20), %eax
ja L(page_cross)
VMOVU (%rdi), %VMM(1)
VPCMPNE %VMM(1), %VMM(0), %k1
VPTEST %VMM(1), %VMM(1), %k0{%k1}
KMOV %k0, %VRAX
/* Compare [w]char for null, mask bit will be set for match. */
# ifdef USE_AS_WCSCHR
sub $VEC_MATCH_MASK, %VRAX
# else
inc %VRAX
# endif
jz L(align_more)
bsf %VRAX, %VRAX
# ifdef USE_AS_WCSCHR
leaq (%rdi, %rax, CHAR_SIZE), %rax
# else
add %rdi, %rax
# endif
# ifndef USE_AS_STRCHRNUL
cmp (%rax), %CHAR_REG
jne L(zero)
ret
L(zero):
xorl %eax, %eax
# endif
ret
L(ret_vec_x3):
subq $-VEC_SIZE, %rdi
L(ret_vec_x2):
subq $-VEC_SIZE, %rdi
L(ret_vec_x1):
bsf %VRAX, %VRAX
# ifdef USE_AS_WCSCHR
leaq (%rdi, %rax, CHAR_SIZE), %rax
# else
add %rdi, %rax
# endif
# ifndef USE_AS_STRCHRNUL
cmp (%rax), %CHAR_REG
jne L(zero)
# endif
ret
L(page_cross):
mov %rdi, %rax
movl %edi, %ecx
# ifdef USE_AS_WCSCHR
/* Calculate number of compare result bits to be skipped for
wide string alignment adjustment. */
andl $(VEC_SIZE - 1), %ecx
sarl $2, %ecx
# endif
/* ecx contains number of w[char] to be skipped as a result
of address alignment. */
andq $-VEC_SIZE, %rax
VMOVA (%rax), %VMM(1)
VPCMPNE %VMM(1), %VMM(0), %k1
VPTEST %VMM(1), %VMM(1), %k0{%k1}
KMOV %k0, %VRAX
# ifdef USE_AS_WCSCHR
sub $VEC_MATCH_MASK, %VRAX
# else
inc %VRAX
# endif
/* Ignore number of character for alignment adjustment. */
shr %cl, %VRAX
jz L(align_more)
bsf %VRAX, %VRAX
# ifdef USE_AS_WCSCHR
leaq (%rdi, %rax, CHAR_SIZE), %rax
# else
addq %rdi, %rax
# endif
# ifndef USE_AS_STRCHRNUL
cmp (%rax), %CHAR_REG
jne L(zero)
# endif
ret
L(align_more):
/* Align rax to VEC_SIZE. */
andq $-VEC_SIZE, %rdi
/* Loop unroll 4 times for 4 vector loop. */
VMOVA VEC_SIZE(%rdi), %VMM(1)
VPCMPNE %VMM(1), %VMM(0), %k1
VPTEST %VMM(1), %VMM(1), %k0{%k1}
/* Increment rdi by vector size for further comparison and
return. */
subq $-VEC_SIZE, %rdi
KMOV %k0, %VRAX
# ifdef USE_AS_WCSCHR
sub $VEC_MATCH_MASK, %VRAX
# else
inc %VRAX
# endif
jnz L(ret_vec_x1)
VMOVA VEC_SIZE(%rdi), %VMM(1)
VPCMPNE %VMM(1), %VMM(0), %k1
VPTEST %VMM(1), %VMM(1), %k0{%k1}
KMOV %k0, %VRAX
# ifdef USE_AS_WCSCHR
sub $VEC_MATCH_MASK, %VRAX
# else
inc %VRAX
# endif
jnz L(ret_vec_x2)
VMOVA (VEC_SIZE * 2)(%rdi), %VMM(1)
VPCMPNE %VMM(1), %VMM(0), %k1
VPTEST %VMM(1), %VMM(1), %k0{%k1}
KMOV %k0, %VRAX
# ifdef USE_AS_WCSCHR
sub $VEC_MATCH_MASK, %VRAX
# else
inc %VRAX
# endif
jnz L(ret_vec_x3)
VMOVA (VEC_SIZE * 3)(%rdi), %VMM(1)
VPCMPNE %VMM(1), %VMM(0), %k1
VPTEST %VMM(1), %VMM(1), %k0{%k1}
KMOV %k0, %VRDX
# ifdef USE_AS_WCSCHR
sub $VEC_MATCH_MASK, %VRDX
# else
inc %VRDX
# endif
jnz L(ret_vec_x4)
/* Align address to VEC_SIZE * 4 for loop. */
andq $-(VEC_SIZE * 4), %rdi
L(loop):
/* VPMINU and VPCMP combination provide better performance as
compared to alternative combinations. */
VMOVA (VEC_SIZE * 4)(%rdi), %VMM(1)
VMOVA (VEC_SIZE * 5)(%rdi), %VMM(2)
VMOVA (VEC_SIZE * 6)(%rdi), %VMM(3)
VMOVA (VEC_SIZE * 7)(%rdi), %VMM(4)
VPCMPNE %VMM(1), %VMM(0), %k1
VPCMPNE %VMM(2), %VMM(0), %k2
VPMINU %VMM(2), %VMM(1), %VMM(2)
VPCMPNE %VMM(3), %VMM(0), %k3{%k1}
VPCMPNE %VMM(4), %VMM(0), %k4{%k2}
VPMINU %VMM(4), %VMM(3), %VMM(4)
VPMINU %VMM(2), %VMM(4), %VMM(4){%k3}{z}
VPTEST %VMM(4), %VMM(4), %k5{%k4}
KMOV %k5, %VRDX
subq $-(VEC_SIZE * 4), %rdi
# ifdef USE_AS_WCSCHR
sub $VEC_MATCH_MASK, %VRDX
# else
inc %VRDX
# endif
jz L(loop)
VPTEST %VMM(1), %VMM(1), %k0{%k1}
KMOV %k0, %VRAX
# ifdef USE_AS_WCSCHR
sub $VEC_MATCH_MASK, %VRAX
# else
inc %VRAX
# endif
jnz L(ret_vec_x1)
VPTEST %VMM(2), %VMM(2), %k0{%k2}
KMOV %k0, %VRAX
/* At this point, if k1 is non zero, null char must be in the
second vector. */
# ifdef USE_AS_WCSCHR
sub $VEC_MATCH_MASK, %VRAX
# else
inc %VRAX
# endif
jnz L(ret_vec_x2)
VPTEST %VMM(3), %VMM(3), %k0{%k3}
KMOV %k0, %VRAX
# ifdef USE_AS_WCSCHR
sub $VEC_MATCH_MASK, %VRAX
# else
inc %VRAX
# endif
jnz L(ret_vec_x3)
/* At this point null [w]char must be in the fourth vector so no
need to check. */
L(ret_vec_x4):
bsf %VRDX, %VRDX
leaq (VEC_SIZE * 3)(%rdi, %rdx, CHAR_SIZE), %rax
# ifndef USE_AS_STRCHRNUL
cmp (%rax), %CHAR_REG
jne L(zero_2)
# endif
ret
# ifndef USE_AS_STRCHRNUL
L(zero_2):
xor %eax, %eax
ret
# endif
END (STRCHR)
#endif
|
