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04067002 | 1 | /* Optimized strcmp implementation for PowerPC64. |
b168057a | 2 | Copyright (C) 2003-2015 Free Software Foundation, Inc. |
04067002 UD |
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 | |
59ba27a6 PE |
16 | License along with the GNU C Library; if not, see |
17 | <http://www.gnu.org/licenses/>. */ | |
04067002 UD |
18 | |
19 | #include <sysdep.h> | |
04067002 UD |
20 | |
21 | /* See strlen.s for comments on how the end-of-string testing works. */ | |
22 | ||
23 | /* int [r3] strncmp (const char *s1 [r3], const char *s2 [r4], size_t size [r5]) */ | |
24 | ||
2d67d91a | 25 | EALIGN (strncmp, 4, 0) |
04067002 UD |
26 | CALL_MCOUNT 3 |
27 | ||
8a7413f9 | 28 | #define rTMP2 r0 |
04067002 UD |
29 | #define rRTN r3 |
30 | #define rSTR1 r3 /* first string arg */ | |
31 | #define rSTR2 r4 /* second string arg */ | |
32 | #define rN r5 /* max string length */ | |
04067002 UD |
33 | #define rWORD1 r6 /* current word in s1 */ |
34 | #define rWORD2 r7 /* current word in s2 */ | |
35 | #define rWORD3 r10 | |
36 | #define rWORD4 r11 | |
37 | #define rFEFE r8 /* constant 0xfefefefefefefeff (-0x0101010101010101) */ | |
38 | #define r7F7F r9 /* constant 0x7f7f7f7f7f7f7f7f */ | |
39 | #define rNEG r10 /* ~(word in s1 | 0x7f7f7f7f7f7f7f7f) */ | |
40 | #define rBITDIF r11 /* bits that differ in s1 & s2 words */ | |
8a7413f9 | 41 | #define rTMP r12 |
04067002 UD |
42 | |
43 | dcbt 0,rSTR1 | |
44 | or rTMP, rSTR2, rSTR1 | |
45 | lis r7F7F, 0x7f7f | |
46 | dcbt 0,rSTR2 | |
47 | clrldi. rTMP, rTMP, 61 | |
48 | cmpldi cr1, rN, 0 | |
49 | lis rFEFE, -0x101 | |
50 | bne L(unaligned) | |
2ccdea26 | 51 | /* We are doubleword aligned so set up for two loops. first a double word |
04067002 UD |
52 | loop, then fall into the byte loop if any residual. */ |
53 | srdi. rTMP, rN, 3 | |
54 | clrldi rN, rN, 61 | |
55 | addi rFEFE, rFEFE, -0x101 | |
56 | addi r7F7F, r7F7F, 0x7f7f | |
7a41d99a | 57 | cmpldi cr1, rN, 0 |
04067002 UD |
58 | beq L(unaligned) |
59 | ||
60 | mtctr rTMP /* Power4 wants mtctr 1st in dispatch group. */ | |
61 | ld rWORD1, 0(rSTR1) | |
62 | ld rWORD2, 0(rSTR2) | |
63 | sldi rTMP, rFEFE, 32 | |
64 | insrdi r7F7F, r7F7F, 32, 0 | |
65 | add rFEFE, rFEFE, rTMP | |
66 | b L(g1) | |
67 | ||
7a41d99a | 68 | L(g0): |
04067002 UD |
69 | ldu rWORD1, 8(rSTR1) |
70 | bne- cr1, L(different) | |
71 | ldu rWORD2, 8(rSTR2) | |
72 | L(g1): add rTMP, rFEFE, rWORD1 | |
73 | nor rNEG, r7F7F, rWORD1 | |
74 | bdz L(tail) | |
75 | and. rTMP, rTMP, rNEG | |
76 | cmpd cr1, rWORD1, rWORD2 | |
77 | beq+ L(g0) | |
7a41d99a | 78 | |
04067002 UD |
79 | /* OK. We've hit the end of the string. We need to be careful that |
80 | we don't compare two strings as different because of gunk beyond | |
81 | the end of the strings... */ | |
7a41d99a | 82 | |
8a7413f9 AM |
83 | #ifdef __LITTLE_ENDIAN__ |
84 | L(endstring): | |
85 | addi rTMP2, rTMP, -1 | |
86 | beq cr1, L(equal) | |
87 | andc rTMP2, rTMP2, rTMP | |
88 | rldimi rTMP2, rTMP2, 1, 0 | |
89 | and rWORD2, rWORD2, rTMP2 /* Mask off gunk. */ | |
90 | and rWORD1, rWORD1, rTMP2 | |
91 | cmpd cr1, rWORD1, rWORD2 | |
92 | beq cr1, L(equal) | |
93 | xor rBITDIF, rWORD1, rWORD2 /* rBITDIF has bits that differ. */ | |
94 | neg rNEG, rBITDIF | |
95 | and rNEG, rNEG, rBITDIF /* rNEG has LS bit that differs. */ | |
96 | cntlzd rNEG, rNEG /* bitcount of the bit. */ | |
97 | andi. rNEG, rNEG, 56 /* bitcount to LS byte that differs. */ | |
98 | sld rWORD1, rWORD1, rNEG /* shift left to clear MS bytes. */ | |
99 | sld rWORD2, rWORD2, rNEG | |
100 | xor. rBITDIF, rWORD1, rWORD2 | |
101 | sub rRTN, rWORD1, rWORD2 | |
102 | blt- L(highbit) | |
103 | sradi rRTN, rRTN, 63 /* must return an int. */ | |
104 | ori rRTN, rRTN, 1 | |
105 | blr | |
106 | L(equal): | |
107 | li rRTN, 0 | |
108 | blr | |
109 | ||
110 | L(different): | |
111 | ld rWORD1, -8(rSTR1) | |
112 | xor rBITDIF, rWORD1, rWORD2 /* rBITDIF has bits that differ. */ | |
113 | neg rNEG, rBITDIF | |
114 | and rNEG, rNEG, rBITDIF /* rNEG has LS bit that differs. */ | |
115 | cntlzd rNEG, rNEG /* bitcount of the bit. */ | |
116 | andi. rNEG, rNEG, 56 /* bitcount to LS byte that differs. */ | |
117 | sld rWORD1, rWORD1, rNEG /* shift left to clear MS bytes. */ | |
118 | sld rWORD2, rWORD2, rNEG | |
119 | xor. rBITDIF, rWORD1, rWORD2 | |
120 | sub rRTN, rWORD1, rWORD2 | |
121 | blt- L(highbit) | |
122 | sradi rRTN, rRTN, 63 | |
123 | ori rRTN, rRTN, 1 | |
124 | blr | |
125 | L(highbit): | |
126 | sradi rRTN, rWORD2, 63 | |
127 | ori rRTN, rRTN, 1 | |
128 | blr | |
129 | ||
130 | #else | |
04067002 UD |
131 | L(endstring): |
132 | and rTMP, r7F7F, rWORD1 | |
133 | beq cr1, L(equal) | |
134 | add rTMP, rTMP, r7F7F | |
135 | xor. rBITDIF, rWORD1, rWORD2 | |
04067002 UD |
136 | andc rNEG, rNEG, rTMP |
137 | blt- L(highbit) | |
138 | cntlzd rBITDIF, rBITDIF | |
139 | cntlzd rNEG, rNEG | |
140 | addi rNEG, rNEG, 7 | |
141 | cmpd cr1, rNEG, rBITDIF | |
142 | sub rRTN, rWORD1, rWORD2 | |
143 | blt- cr1, L(equal) | |
8a7413f9 | 144 | sradi rRTN, rRTN, 63 /* must return an int. */ |
04067002 UD |
145 | ori rRTN, rRTN, 1 |
146 | blr | |
147 | L(equal): | |
148 | li rRTN, 0 | |
149 | blr | |
150 | ||
151 | L(different): | |
8a7413f9 | 152 | ld rWORD1, -8(rSTR1) |
04067002 UD |
153 | xor. rBITDIF, rWORD1, rWORD2 |
154 | sub rRTN, rWORD1, rWORD2 | |
155 | blt- L(highbit) | |
156 | sradi rRTN, rRTN, 63 | |
157 | ori rRTN, rRTN, 1 | |
158 | blr | |
159 | L(highbit): | |
8a7413f9 AM |
160 | sradi rRTN, rWORD2, 63 |
161 | ori rRTN, rRTN, 1 | |
04067002 | 162 | blr |
8a7413f9 | 163 | #endif |
04067002 UD |
164 | |
165 | /* Oh well. In this case, we just do a byte-by-byte comparison. */ | |
166 | .align 4 | |
167 | L(tail): | |
168 | and. rTMP, rTMP, rNEG | |
169 | cmpd cr1, rWORD1, rWORD2 | |
170 | bne- L(endstring) | |
171 | addi rSTR1, rSTR1, 8 | |
172 | bne- cr1, L(different) | |
173 | addi rSTR2, rSTR2, 8 | |
174 | cmpldi cr1, rN, 0 | |
175 | L(unaligned): | |
176 | mtctr rN /* Power4 wants mtctr 1st in dispatch group */ | |
177 | ble cr1, L(ux) | |
178 | L(uz): | |
179 | lbz rWORD1, 0(rSTR1) | |
180 | lbz rWORD2, 0(rSTR2) | |
181 | .align 4 | |
182 | L(u1): | |
183 | cmpdi cr1, rWORD1, 0 | |
184 | bdz L(u4) | |
185 | cmpd rWORD1, rWORD2 | |
186 | beq- cr1, L(u4) | |
4420675c | 187 | bne- L(u4) |
04067002 UD |
188 | lbzu rWORD3, 1(rSTR1) |
189 | lbzu rWORD4, 1(rSTR2) | |
04067002 UD |
190 | cmpdi cr1, rWORD3, 0 |
191 | bdz L(u3) | |
192 | cmpd rWORD3, rWORD4 | |
193 | beq- cr1, L(u3) | |
4420675c | 194 | bne- L(u3) |
04067002 UD |
195 | lbzu rWORD1, 1(rSTR1) |
196 | lbzu rWORD2, 1(rSTR2) | |
04067002 UD |
197 | cmpdi cr1, rWORD1, 0 |
198 | bdz L(u4) | |
199 | cmpd rWORD1, rWORD2 | |
200 | beq- cr1, L(u4) | |
4420675c | 201 | bne- L(u4) |
04067002 UD |
202 | lbzu rWORD3, 1(rSTR1) |
203 | lbzu rWORD4, 1(rSTR2) | |
04067002 UD |
204 | cmpdi cr1, rWORD3, 0 |
205 | bdz L(u3) | |
206 | cmpd rWORD3, rWORD4 | |
207 | beq- cr1, L(u3) | |
4420675c | 208 | bne- L(u3) |
04067002 UD |
209 | lbzu rWORD1, 1(rSTR1) |
210 | lbzu rWORD2, 1(rSTR2) | |
4420675c | 211 | b L(u1) |
04067002 UD |
212 | |
213 | L(u3): sub rRTN, rWORD3, rWORD4 | |
7a41d99a | 214 | blr |
04067002 UD |
215 | L(u4): sub rRTN, rWORD1, rWORD2 |
216 | blr | |
217 | L(ux): | |
218 | li rRTN, 0 | |
219 | blr | |
2d67d91a | 220 | END (strncmp) |
04067002 | 221 | libc_hidden_builtin_def (strncmp) |