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
|
/* strcmp with unaligned loads
Copyright (C) 2013-2015 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
<http://www.gnu.org/licenses/>. */
#include "sysdep.h"
.text
ENTRY (strcmp)
movl %edi, %eax
xorl %edx, %edx
pxor %xmm7, %xmm7
orl %esi, %eax
andl $4095, %eax
cmpl $4032, %eax
jg L(cross_page)
movdqu (%rdi), %xmm1
movdqu (%rsi), %xmm0
pcmpeqb %xmm1, %xmm0
pminub %xmm1, %xmm0
pxor %xmm1, %xmm1
pcmpeqb %xmm1, %xmm0
pmovmskb %xmm0, %eax
testq %rax, %rax
je L(next_48_bytes)
L(return):
bsfq %rax, %rdx
movzbl (%rdi, %rdx), %eax
movzbl (%rsi, %rdx), %edx
subl %edx, %eax
ret
.p2align 4
L(next_48_bytes):
movdqu 16(%rdi), %xmm6
movdqu 16(%rsi), %xmm3
movdqu 32(%rdi), %xmm5
pcmpeqb %xmm6, %xmm3
movdqu 32(%rsi), %xmm2
pminub %xmm6, %xmm3
pcmpeqb %xmm1, %xmm3
movdqu 48(%rdi), %xmm4
pcmpeqb %xmm5, %xmm2
pmovmskb %xmm3, %edx
movdqu 48(%rsi), %xmm0
pminub %xmm5, %xmm2
pcmpeqb %xmm1, %xmm2
pcmpeqb %xmm4, %xmm0
pmovmskb %xmm2, %eax
salq $16, %rdx
pminub %xmm4, %xmm0
pcmpeqb %xmm1, %xmm0
salq $32, %rax
orq %rdx, %rax
pmovmskb %xmm0, %ecx
movq %rcx, %rdx
salq $48, %rdx
orq %rdx, %rax
jne L(return)
L(main_loop_header):
leaq 64(%rdi), %rdx
movl $4096, %ecx
pxor %xmm9, %xmm9
andq $-64, %rdx
subq %rdi, %rdx
leaq (%rdi, %rdx), %rax
addq %rsi, %rdx
movq %rdx, %rsi
andl $4095, %esi
subq %rsi, %rcx
shrq $6, %rcx
movq %rcx, %rsi
jmp L(loop_start)
.p2align 4
L(loop):
addq $64, %rax
addq $64, %rdx
L(loop_start):
testq %rsi, %rsi
leaq -1(%rsi), %rsi
je L(loop_cross_page)
L(back_to_loop):
movdqu (%rdx), %xmm0
movdqu 16(%rdx), %xmm1
movdqa (%rax), %xmm2
movdqa 16(%rax), %xmm3
pcmpeqb %xmm2, %xmm0
movdqu 32(%rdx), %xmm5
pcmpeqb %xmm3, %xmm1
pminub %xmm2, %xmm0
movdqu 48(%rdx), %xmm6
pminub %xmm3, %xmm1
movdqa 32(%rax), %xmm2
pminub %xmm1, %xmm0
movdqa 48(%rax), %xmm3
pcmpeqb %xmm2, %xmm5
pcmpeqb %xmm3, %xmm6
pminub %xmm2, %xmm5
pminub %xmm3, %xmm6
pminub %xmm5, %xmm0
pminub %xmm6, %xmm0
pcmpeqb %xmm7, %xmm0
pmovmskb %xmm0, %ecx
testl %ecx, %ecx
je L(loop)
pcmpeqb %xmm7, %xmm5
movdqu (%rdx), %xmm0
pcmpeqb %xmm7, %xmm1
movdqa (%rax), %xmm2
pcmpeqb %xmm2, %xmm0
pminub %xmm2, %xmm0
pcmpeqb %xmm7, %xmm6
pcmpeqb %xmm7, %xmm0
pmovmskb %xmm1, %ecx
pmovmskb %xmm5, %r8d
pmovmskb %xmm0, %edi
salq $16, %rcx
salq $32, %r8
pmovmskb %xmm6, %esi
orq %r8, %rcx
orq %rdi, %rcx
salq $48, %rsi
orq %rsi, %rcx
bsfq %rcx, %rcx
movzbl (%rax, %rcx), %eax
movzbl (%rdx, %rcx), %edx
subl %edx, %eax
ret
.p2align 4
L(loop_cross_page):
xor %r10, %r10
movq %rdx, %r9
and $63, %r9
subq %r9, %r10
movdqa (%rdx, %r10), %xmm0
movdqa 16(%rdx, %r10), %xmm1
movdqu (%rax, %r10), %xmm2
movdqu 16(%rax, %r10), %xmm3
pcmpeqb %xmm2, %xmm0
movdqa 32(%rdx, %r10), %xmm5
pcmpeqb %xmm3, %xmm1
pminub %xmm2, %xmm0
movdqa 48(%rdx, %r10), %xmm6
pminub %xmm3, %xmm1
movdqu 32(%rax, %r10), %xmm2
movdqu 48(%rax, %r10), %xmm3
pcmpeqb %xmm2, %xmm5
pcmpeqb %xmm3, %xmm6
pminub %xmm2, %xmm5
pminub %xmm3, %xmm6
pcmpeqb %xmm7, %xmm0
pcmpeqb %xmm7, %xmm1
pcmpeqb %xmm7, %xmm5
pcmpeqb %xmm7, %xmm6
pmovmskb %xmm1, %ecx
pmovmskb %xmm5, %r8d
pmovmskb %xmm0, %edi
salq $16, %rcx
salq $32, %r8
pmovmskb %xmm6, %esi
orq %r8, %rdi
orq %rcx, %rdi
salq $48, %rsi
orq %rsi, %rdi
movq %r9, %rcx
movq $63, %rsi
shrq %cl, %rdi
test %rdi, %rdi
je L(back_to_loop)
bsfq %rdi, %rcx
movzbl (%rax, %rcx), %eax
movzbl (%rdx, %rcx), %edx
subl %edx, %eax
ret
.p2align 4
L(cross_page_loop):
cmpb %cl, %al
jne L(different)
addq $1, %rdx
cmpq $64, %rdx
je L(main_loop_header)
L(cross_page):
movzbl (%rdi, %rdx), %eax
movzbl (%rsi, %rdx), %ecx
testb %al, %al
jne L(cross_page_loop)
xorl %eax, %eax
L(different):
subl %ecx, %eax
ret
END (strcmp)
libc_hidden_builtin_def (strcmp)
|
