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a72cc2b2 | 1 | /* Optimized strcmp implementation for PowerPC476. |
d614a753 | 2 | Copyright (C) 2010-2020 Free Software Foundation, Inc. |
a72cc2b2 LM |
3 | This file is part of the GNU C Library. |
4 | ||
5 | The GNU C Library is free software; you can redistribute it and/or | |
6 | modify it under the terms of the GNU Lesser General Public | |
7 | License as published by the Free Software Foundation; either | |
8 | version 2.1 of the License, or (at your option) any later version. | |
9 | ||
10 | The GNU C Library is distributed in the hope that it will be useful, | |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
13 | Lesser General Public License for more details. | |
14 | ||
15 | You should have received a copy of the GNU Lesser General Public | |
ab84e3ff | 16 | License along with the GNU C Library. If not, see |
5a82c748 | 17 | <https://www.gnu.org/licenses/>. */ |
a72cc2b2 LM |
18 | |
19 | #include <sysdep.h> | |
a72cc2b2 LM |
20 | |
21 | /* strcmp | |
22 | ||
23 | Register Use | |
24 | r0:temp return equality | |
25 | r3:source1 address, return equality | |
26 | r4:source2 address | |
27 | ||
28 | Implementation description | |
29 | Check 2 words from src1 and src2. If unequal jump to end and | |
30 | return src1 > src2 or src1 < src2. | |
31 | If null check bytes before null and then jump to end and | |
32 | return src1 > src2, src1 < src2 or src1 = src2. | |
33 | If src1 = src2 and no null, repeat. */ | |
34 | ||
b5510883 | 35 | EALIGN (strcmp,5,0) |
a72cc2b2 LM |
36 | neg r7,r3 |
37 | clrlwi r7,r7,20 | |
38 | neg r8,r4 | |
39 | clrlwi r8,r8,20 | |
40 | srwi. r7,r7,5 | |
41 | beq L(byte_loop) | |
42 | srwi. r8,r8,5 | |
43 | beq L(byte_loop) | |
44 | cmplw r7,r8 | |
45 | mtctr r7 | |
46 | ble L(big_loop) | |
47 | mtctr r8 | |
48 | ||
49 | L(big_loop): | |
50 | lwz r5,0(r3) | |
51 | lwz r6,4(r3) | |
52 | lwz r8,0(r4) | |
53 | lwz r9,4(r4) | |
54 | dlmzb. r12,r5,r6 | |
55 | bne L(end_check) | |
56 | cmplw r5,r8 | |
57 | bne L(st1) | |
58 | cmplw r6,r9 | |
59 | bne L(st1) | |
60 | lwz r5,8(r3) | |
61 | lwz r6,12(r3) | |
62 | lwz r8,8(r4) | |
63 | lwz r9,12(r4) | |
64 | dlmzb. r12,r5,r6 | |
65 | bne L(end_check) | |
66 | cmplw r5,r8 | |
67 | bne L(st1) | |
68 | cmplw r6,r9 | |
69 | bne L(st1) | |
70 | lwz r5,16(r3) | |
71 | lwz r6,20(r3) | |
72 | lwz r8,16(r4) | |
73 | lwz r9,20(r4) | |
74 | dlmzb. r12,r5,r6 | |
75 | bne L(end_check) | |
76 | cmplw r5,r8 | |
77 | bne L(st1) | |
78 | cmplw r6,r9 | |
79 | bne L(st1) | |
80 | lwz r5,24(r3) | |
81 | lwz r6,28(r3) | |
82 | addi r3,r3,0x20 | |
83 | lwz r8,24(r4) | |
84 | lwz r9,28(r4) | |
85 | addi r4,r4,0x20 | |
86 | dlmzb. r12,r5,r6 | |
87 | bne L(end_check) | |
88 | cmplw r5,r8 | |
89 | bne L(st1) | |
90 | cmplw r6,r9 | |
91 | bne L(st1) | |
92 | bdnz L(big_loop) | |
93 | b L(byte_loop) | |
94 | ||
95 | L(end_check): | |
96 | subfic r12,r12,4 | |
97 | blt L(end_check2) | |
98 | rlwinm r12,r12,3,0,31 | |
99 | srw r5,r5,r12 | |
100 | srw r8,r8,r12 | |
101 | cmplw r5,r8 | |
102 | bne L(st1) | |
103 | b L(end_strcmp) | |
104 | ||
105 | L(end_check2): | |
106 | addi r12,r12,4 | |
107 | cmplw r5,r8 | |
108 | rlwinm r12,r12,3,0,31 | |
109 | bne L(st1) | |
110 | srw r6,r6,r12 | |
111 | srw r9,r9,r12 | |
112 | cmplw r6,r9 | |
113 | bne L(st1) | |
114 | ||
115 | L(end_strcmp): | |
116 | addi r3,r0,0 | |
117 | blr | |
118 | ||
119 | L(st1): | |
120 | mfcr r3 | |
121 | blr | |
122 | ||
123 | L(byte_loop): | |
124 | lbz r5,0(r3) | |
125 | addi r3,r3,1 | |
126 | lbz r6,0(r4) | |
127 | addi r4,r4,1 | |
128 | cmplw r5,r6 | |
129 | bne L(st1) | |
130 | cmpwi r5,0 | |
131 | beq L(end_strcmp) | |
132 | b L(byte_loop) | |
b5510883 | 133 | END (strcmp) |
a72cc2b2 | 134 | libc_hidden_builtin_def (strcmp) |