about summary refs log tree commit diff
path: root/sysdeps/x86_64/multiarch/strchr-avx2.S
blob: 476c20c2899ded40c1f3a9f96489bb0fa9415d0b (plain) (blame)
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
/* strchr/strchrnul optimized with AVX2.
   Copyright (C) 2017-2021 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/>.  */

#if IS_IN (libc)

# include <sysdep.h>

# ifndef STRCHR
#  define STRCHR	__strchr_avx2
# endif

# ifdef USE_AS_WCSCHR
#  define VPBROADCAST	vpbroadcastd
#  define VPCMPEQ	vpcmpeqd
#  define VPMINU	vpminud
#  define CHAR_REG	esi
# else
#  define VPBROADCAST	vpbroadcastb
#  define VPCMPEQ	vpcmpeqb
#  define VPMINU	vpminub
#  define CHAR_REG	sil
# endif

# ifndef VZEROUPPER
#  define VZEROUPPER	vzeroupper
# endif

# define VEC_SIZE 32
# define PAGE_SIZE 4096

	.section .text.avx,"ax",@progbits
ENTRY (STRCHR)
	movl	%edi, %ecx
# ifndef USE_AS_STRCHRNUL
	xorl	%edx, %edx
# endif

	/* Broadcast CHAR to YMM0.	*/
	vmovd	%esi, %xmm0
	vpxor	%xmm9, %xmm9, %xmm9
	VPBROADCAST %xmm0, %ymm0

	/* Check if we cross page boundary with one vector load.  */
	andl	$(PAGE_SIZE - 1), %ecx
	cmpl	$(PAGE_SIZE - VEC_SIZE), %ecx
	ja  L(cross_page_boundary)

	/* Check the first VEC_SIZE bytes.	Search for both CHAR and the
	   null byte.  */
	vmovdqu	(%rdi), %ymm8
	VPCMPEQ %ymm8, %ymm0, %ymm1
	VPCMPEQ %ymm8, %ymm9, %ymm2
	vpor	%ymm1, %ymm2, %ymm1
	vpmovmskb %ymm1, %eax
	testl	%eax, %eax
	jz	L(more_vecs)
	tzcntl	%eax, %eax
	/* Found CHAR or the null byte.	 */
	addq	%rdi, %rax
# ifndef USE_AS_STRCHRNUL
	cmp (%rax), %CHAR_REG
	cmovne	%rdx, %rax
# endif
	VZEROUPPER
	ret

	.p2align 4
L(more_vecs):
	/* Align data for aligned loads in the loop.  */
	andq	$-VEC_SIZE, %rdi
L(aligned_more):

	/* Check the next 4 * VEC_SIZE.	 Only one VEC_SIZE at a time
	   since data is only aligned to VEC_SIZE.	*/
	vmovdqa	VEC_SIZE(%rdi), %ymm8
	addq	$VEC_SIZE, %rdi
	VPCMPEQ %ymm8, %ymm0, %ymm1
	VPCMPEQ %ymm8, %ymm9, %ymm2
	vpor	%ymm1, %ymm2, %ymm1
	vpmovmskb %ymm1, %eax
	testl	%eax, %eax
	jnz	L(first_vec_x0)

	vmovdqa	VEC_SIZE(%rdi), %ymm8
	VPCMPEQ %ymm8, %ymm0, %ymm1
	VPCMPEQ %ymm8, %ymm9, %ymm2
	vpor	%ymm1, %ymm2, %ymm1
	vpmovmskb %ymm1, %eax
	testl	%eax, %eax
	jnz	L(first_vec_x1)

	vmovdqa	(VEC_SIZE * 2)(%rdi), %ymm8
	VPCMPEQ %ymm8, %ymm0, %ymm1
	VPCMPEQ %ymm8, %ymm9, %ymm2
	vpor	%ymm1, %ymm2, %ymm1
	vpmovmskb %ymm1, %eax
	testl	%eax, %eax
	jnz	L(first_vec_x2)

	vmovdqa	(VEC_SIZE * 3)(%rdi), %ymm8
	VPCMPEQ %ymm8, %ymm0, %ymm1
	VPCMPEQ %ymm8, %ymm9, %ymm2
	vpor	%ymm1, %ymm2, %ymm1
	vpmovmskb %ymm1, %eax
	testl	%eax, %eax
	jz	L(prep_loop_4x)

	tzcntl	%eax, %eax
	leaq	(VEC_SIZE * 3)(%rdi, %rax), %rax
# ifndef USE_AS_STRCHRNUL
	cmp (%rax), %CHAR_REG
	cmovne	%rdx, %rax
# endif
	VZEROUPPER
	ret

	.p2align 4
L(first_vec_x0):
	tzcntl	%eax, %eax
	/* Found CHAR or the null byte.	 */
	addq	%rdi, %rax
# ifndef USE_AS_STRCHRNUL
	cmp (%rax), %CHAR_REG
	cmovne	%rdx, %rax
# endif
	VZEROUPPER
	ret

	.p2align 4
L(first_vec_x1):
	tzcntl	%eax, %eax
	leaq	VEC_SIZE(%rdi, %rax), %rax
# ifndef USE_AS_STRCHRNUL
	cmp (%rax), %CHAR_REG
	cmovne	%rdx, %rax
# endif
	VZEROUPPER
	ret

	.p2align 4
L(first_vec_x2):
	tzcntl	%eax, %eax
	/* Found CHAR or the null byte.	 */
	leaq	(VEC_SIZE * 2)(%rdi, %rax), %rax
# ifndef USE_AS_STRCHRNUL
	cmp (%rax), %CHAR_REG
	cmovne	%rdx, %rax
# endif
	VZEROUPPER
	ret

L(prep_loop_4x):
	/* Align data to 4 * VEC_SIZE.	*/
	andq	$-(VEC_SIZE * 4), %rdi

	.p2align 4
L(loop_4x_vec):
	/* Compare 4 * VEC at a time forward.  */
	vmovdqa	(VEC_SIZE * 4)(%rdi), %ymm5
	vmovdqa	(VEC_SIZE * 5)(%rdi), %ymm6
	vmovdqa	(VEC_SIZE * 6)(%rdi), %ymm7
	vmovdqa	(VEC_SIZE * 7)(%rdi), %ymm8

	/* Leaves only CHARS matching esi as 0.	 */
	vpxor	%ymm5, %ymm0, %ymm1
	vpxor	%ymm6, %ymm0, %ymm2
	vpxor	%ymm7, %ymm0, %ymm3
	vpxor	%ymm8, %ymm0, %ymm4

	VPMINU	%ymm1, %ymm5, %ymm1
	VPMINU	%ymm2, %ymm6, %ymm2
	VPMINU	%ymm3, %ymm7, %ymm3
	VPMINU	%ymm4, %ymm8, %ymm4

	VPMINU	%ymm1, %ymm2, %ymm5
	VPMINU	%ymm3, %ymm4, %ymm6

	VPMINU	%ymm5, %ymm6, %ymm5

	VPCMPEQ %ymm5, %ymm9, %ymm5
	vpmovmskb %ymm5, %eax

	addq	$(VEC_SIZE * 4), %rdi
	testl	%eax, %eax
	jz  L(loop_4x_vec)

	VPCMPEQ %ymm1, %ymm9, %ymm1
	vpmovmskb %ymm1, %eax
	testl	%eax, %eax
	jnz	L(first_vec_x0)

	VPCMPEQ %ymm2, %ymm9, %ymm2
	vpmovmskb %ymm2, %eax
	testl	%eax, %eax
	jnz	L(first_vec_x1)

	VPCMPEQ %ymm3, %ymm9, %ymm3
	VPCMPEQ %ymm4, %ymm9, %ymm4
	vpmovmskb %ymm3, %ecx
	vpmovmskb %ymm4, %eax
	salq	$32, %rax
	orq %rcx, %rax
	tzcntq  %rax, %rax
	leaq	(VEC_SIZE * 2)(%rdi, %rax), %rax
# ifndef USE_AS_STRCHRNUL
	cmp (%rax), %CHAR_REG
	cmovne	%rdx, %rax
# endif
	VZEROUPPER
	ret

	/* Cold case for crossing page with first load.	 */
	.p2align 4
L(cross_page_boundary):
	andq	$-VEC_SIZE, %rdi
	andl	$(VEC_SIZE - 1), %ecx

	vmovdqa	(%rdi), %ymm8
	VPCMPEQ %ymm8, %ymm0, %ymm1
	VPCMPEQ %ymm8, %ymm9, %ymm2
	vpor	%ymm1, %ymm2, %ymm1
	vpmovmskb %ymm1, %eax
	/* Remove the leading bits.	 */
	sarxl	%ecx, %eax, %eax
	testl	%eax, %eax
	jz	L(aligned_more)
	tzcntl	%eax, %eax
	addq	%rcx, %rdi
	addq	%rdi, %rax
# ifndef USE_AS_STRCHRNUL
	cmp (%rax), %CHAR_REG
	cmovne	%rdx, %rax
# endif
	VZEROUPPER
	ret

END (STRCHR)
# endif