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a72cc2b2 | 1 | /* Optimized strncmp implementation for PowerPC476. |
b168057a | 2 | Copyright (C) 2010-2015 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 PE |
16 | License along with the GNU C Library. If not, see |
17 | <http://www.gnu.org/licenses/>. */ | |
a72cc2b2 LM |
18 | |
19 | #include <sysdep.h> | |
a72cc2b2 LM |
20 | |
21 | /* strncmp | |
22 | ||
23 | Register Use | |
24 | r0:temp return equality | |
25 | r3:source1 address, return equality | |
26 | r4:source2 address | |
27 | r5:byte count | |
28 | ||
29 | Implementation description | |
30 | Touch in 3 lines of D-cache. | |
31 | If source1 or source2 is unaligned copy 0-3 bytes to make source1 aligned | |
32 | Check 2 words from src1 and src2. If unequal jump to end and | |
33 | return src1 > src2 or src1 < src2. | |
34 | If null check bytes before null and then jump to end and | |
35 | return src1 > src2, src1 < src2 or src1 = src2. | |
36 | If count = zero check bytes before zero counter and then jump to end and | |
37 | return src1 > src2, src1 < src2 or src1 = src2. | |
38 | If src1 = src2 and no null, repeat. */ | |
39 | ||
b5510883 | 40 | EALIGN (strncmp,5,0) |
a72cc2b2 LM |
41 | neg r7,r3 |
42 | clrlwi r7,r7,20 | |
43 | neg r8,r4 | |
44 | clrlwi r8,r8,20 | |
45 | srwi. r7,r7,3 | |
46 | beq L(prebyte_count_loop) | |
47 | srwi. r8,r8,3 | |
48 | beq L(prebyte_count_loop) | |
49 | cmplw r7,r8 | |
50 | mtctr r7 | |
51 | ble L(preword2_count_loop) | |
52 | mtctr r8 | |
53 | ||
54 | L(preword2_count_loop): | |
55 | srwi. r6,r5,3 | |
56 | beq L(prebyte_count_loop) | |
57 | mfctr r7 | |
58 | cmplw r6,r7 | |
59 | bgt L(set_count_loop) | |
60 | mtctr r6 | |
61 | clrlwi r5,r5,29 | |
62 | ||
63 | L(word2_count_loop): | |
64 | lwz r10,0(r3) | |
65 | lwz r6,4(r3) | |
66 | addi r3,r3,0x08 | |
67 | lwz r8,0(r4) | |
68 | lwz r9,4(r4) | |
69 | addi r4,r4,0x08 | |
70 | dlmzb. r12,r10,r6 | |
71 | bne L(end_check) | |
72 | cmplw r10,r8 | |
73 | bne L(st1) | |
74 | cmplw r6,r9 | |
75 | bne L(st1) | |
76 | bdnz L(word2_count_loop) | |
77 | ||
78 | L(prebyte_count_loop): | |
79 | addi r5,r5,1 | |
80 | mtctr r5 | |
81 | bdz L(end_strncmp) | |
82 | ||
83 | L(byte_count_loop): | |
84 | lbz r6,0(r3) | |
85 | addi r3,r3,1 | |
86 | lbz r7,0(r4) | |
87 | addi r4,r4,1 | |
88 | cmplw r6,r7 | |
89 | bne L(st1) | |
90 | cmpwi r6,0 | |
91 | beq L(end_strncmp) | |
92 | bdnz L(byte_count_loop) | |
93 | b L(end_strncmp) | |
94 | ||
95 | L(set_count_loop): | |
96 | slwi r7,r7,3 | |
97 | subf r5,r7,r5 | |
98 | b L(word2_count_loop) | |
99 | ||
100 | L(end_check): | |
101 | subfic r12,r12,4 | |
102 | blt L(end_check2) | |
103 | rlwinm r12,r12,3,0,31 | |
104 | srw r10,r10,r12 | |
105 | srw r8,r8,r12 | |
106 | cmplw r10,r8 | |
107 | bne L(st1) | |
108 | b L(end_strncmp) | |
109 | ||
110 | L(end_check2): | |
111 | addi r12,r12,4 | |
112 | cmplw r10,r8 | |
113 | rlwinm r12,r12,3,0,31 | |
114 | bne L(st1) | |
115 | srw r6,r6,r12 | |
116 | srw r9,r9,r12 | |
117 | cmplw r6,r9 | |
118 | bne L(st1) | |
119 | ||
120 | L(end_strncmp): | |
121 | addi r3,r0,0 | |
122 | blr | |
123 | ||
124 | L(st1): | |
125 | mfcr r3 | |
126 | blr | |
b5510883 | 127 | END (strncmp) |
a72cc2b2 | 128 | libc_hidden_builtin_def (strncmp) |