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
|
/* Optimized strcmp implementation for PowerPC.
Copyright (C) 1997-2022 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 <sysdep.h>
/* See strlen.s for comments on how the end-of-string testing works. */
/* int [r3] strcmp (const char *s1 [r3], const char *s2 [r4]) */
EALIGN (strcmp, 4, 0)
#define rTMP2 r0
#define rRTN r3
#define rSTR1 r3 /* first string arg */
#define rSTR2 r4 /* second string arg */
#define rWORD1 r5 /* current word in s1 */
#define rWORD2 r6 /* current word in s2 */
#define rFEFE r7 /* constant 0xfefefeff (-0x01010101) */
#define r7F7F r8 /* constant 0x7f7f7f7f */
#define rNEG r9 /* ~(word in s1 | 0x7f7f7f7f) */
#define rBITDIF r10 /* bits that differ in s1 & s2 words */
#define rTMP r11
or rTMP, rSTR2, rSTR1
clrlwi. rTMP, rTMP, 30
lis rFEFE, -0x101
bne L(unaligned)
lwz rWORD1, 0(rSTR1)
lwz rWORD2, 0(rSTR2)
lis r7F7F, 0x7f7f
addi rFEFE, rFEFE, -0x101
addi r7F7F, r7F7F, 0x7f7f
b L(g1)
L(g0): lwzu rWORD1, 4(rSTR1)
bne cr1, L(different)
lwzu rWORD2, 4(rSTR2)
L(g1): add rTMP, rFEFE, rWORD1
nor rNEG, r7F7F, rWORD1
and. rTMP, rTMP, rNEG
cmpw cr1, rWORD1, rWORD2
beq+ L(g0)
/* OK. We've hit the end of the string. We need to be careful that
we don't compare two strings as different because of gunk beyond
the end of the strings... */
#ifdef __LITTLE_ENDIAN__
L(endstring):
addi rTMP2, rTMP, -1
andc rTMP2, rTMP2, rTMP
rlwimi rTMP2, rTMP2, 1, 0, 30
and rWORD2, rWORD2, rTMP2 /* Mask off gunk. */
and rWORD1, rWORD1, rTMP2
rlwinm rTMP2, rWORD2, 8, 0xffffffff /* Byte reverse word. */
rlwinm rTMP, rWORD1, 8, 0xffffffff
rlwimi rTMP2, rWORD2, 24, 0, 7
rlwimi rTMP, rWORD1, 24, 0, 7
rlwimi rTMP2, rWORD2, 24, 16, 23
rlwimi rTMP, rWORD1, 24, 16, 23
xor. rBITDIF, rTMP, rTMP2
sub rRTN, rTMP, rTMP2
bgelr+
ori rRTN, rTMP2, 1
blr
L(different):
lwz rWORD1, -4(rSTR1)
rlwinm rTMP2, rWORD2, 8, 0xffffffff /* Byte reverse word. */
rlwinm rTMP, rWORD1, 8, 0xffffffff
rlwimi rTMP2, rWORD2, 24, 0, 7
rlwimi rTMP, rWORD1, 24, 0, 7
rlwimi rTMP2, rWORD2, 24, 16, 23
rlwimi rTMP, rWORD1, 24, 16, 23
xor. rBITDIF, rTMP, rTMP2
sub rRTN, rTMP, rTMP2
bgelr+
ori rRTN, rTMP2, 1
blr
#else
L(endstring):
and rTMP, r7F7F, rWORD1
beq cr1, L(equal)
add rTMP, rTMP, r7F7F
xor. rBITDIF, rWORD1, rWORD2
andc rNEG, rNEG, rTMP
blt- L(highbit)
cntlzw rBITDIF, rBITDIF
cntlzw rNEG, rNEG
addi rNEG, rNEG, 7
cmpw cr1, rNEG, rBITDIF
sub rRTN, rWORD1, rWORD2
bgelr+ cr1
L(equal):
li rRTN, 0
blr
L(different):
lwz rWORD1, -4(rSTR1)
xor. rBITDIF, rWORD1, rWORD2
sub rRTN, rWORD1, rWORD2
bgelr+
L(highbit):
ori rRTN, rWORD2, 1
blr
#endif
/* Oh well. In this case, we just do a byte-by-byte comparison. */
.align 4
L(unaligned):
lbz rWORD1, 0(rSTR1)
lbz rWORD2, 0(rSTR2)
b L(u1)
L(u0): lbzu rWORD1, 1(rSTR1)
bne- L(u4)
lbzu rWORD2, 1(rSTR2)
L(u1): cmpwi cr1, rWORD1, 0
beq- cr1, L(u3)
cmpw rWORD1, rWORD2
bne- L(u3)
lbzu rWORD1, 1(rSTR1)
lbzu rWORD2, 1(rSTR2)
cmpwi cr1, rWORD1, 0
cmpw rWORD1, rWORD2
bne+ cr1, L(u0)
L(u3): sub rRTN, rWORD1, rWORD2
blr
L(u4): lbz rWORD1, -1(rSTR1)
sub rRTN, rWORD1, rWORD2
blr
END (strcmp)
libc_hidden_builtin_def (strcmp)
|
