| 1 | /* Optimized strcmp implementation using basic LoongArch instructions. |
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| 2 | Copyright (C) 2023-2024 Free Software Foundation, Inc. |
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| 3 | |
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| 4 | This file is part of the GNU C Library. |
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| 5 | |
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| 6 | The GNU C Library is free software; you can redistribute it and/or |
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| 7 | modify it under the terms of the GNU Lesser General Public |
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| 8 | License as published by the Free Software Foundation; either |
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| 9 | version 2.1 of the License, or (at your option) any later version. |
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| 10 | |
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| 11 | The GNU C Library is distributed in the hope that it will be useful, |
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| 12 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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| 14 | Lesser General Public License for more details. |
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| 15 | |
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| 16 | You should have received a copy of the GNU Lesser General Public |
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| 17 | License along with the GNU C Library. If not, see |
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| 18 | <https://www.gnu.org/licenses/>. */ |
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| 19 | |
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| 20 | #include <sysdep.h> |
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| 21 | #include <sys/regdef.h> |
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| 22 | #include <sys/asm.h> |
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| 23 | |
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| 24 | #if IS_IN (libc) |
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| 25 | # define STRCMP_NAME __strcmp_aligned |
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| 26 | #else |
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| 27 | # define STRCMP_NAME strcmp |
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| 28 | #endif |
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| 29 | |
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| 30 | LEAF(STRCMP_NAME, 6) |
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| 31 | lu12i.w a4, 0x01010 |
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| 32 | andi a2, a0, 0x7 |
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| 33 | ori a4, a4, 0x101 |
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| 34 | andi a3, a1, 0x7 |
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| 35 | |
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| 36 | bstrins.d a4, a4, 63, 32 |
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| 37 | li.d t7, -1 |
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| 38 | li.d t8, 8 |
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| 39 | slli.d a5, a4, 7 |
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| 40 | |
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| 41 | bne a2, a3, L(unaligned) |
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| 42 | bstrins.d a0, zero, 2, 0 |
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| 43 | bstrins.d a1, zero, 2, 0 |
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| 44 | ld.d t0, a0, 0 |
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| 45 | |
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| 46 | ld.d t1, a1, 0 |
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| 47 | slli.d t3, a2, 3 |
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| 48 | sll.d t2, t7, t3 |
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| 49 | orn t0, t0, t2 |
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| 50 | |
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| 51 | |
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| 52 | orn t1, t1, t2 |
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| 53 | sub.d t2, t0, a4 |
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| 54 | andn t3, a5, t0 |
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| 55 | and t2, t2, t3 |
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| 56 | |
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| 57 | bne t0, t1, L(al_end) |
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| 58 | L(al_loop): |
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| 59 | bnez t2, L(ret0) |
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| 60 | ldx.d t0, a0, t8 |
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| 61 | ldx.d t1, a1, t8 |
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| 62 | |
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| 63 | addi.d t8, t8, 8 |
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| 64 | sub.d t2, t0, a4 |
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| 65 | andn t3, a5, t0 |
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| 66 | and t2, t2, t3 |
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| 67 | |
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| 68 | beq t0, t1, L(al_loop) |
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| 69 | L(al_end): |
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| 70 | xor t3, t0, t1 |
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| 71 | or t2, t2, t3 |
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| 72 | ctz.d t3, t2 |
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| 73 | |
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| 74 | |
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| 75 | bstrins.d t3, zero, 2, 0 |
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| 76 | srl.d t0, t0, t3 |
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| 77 | srl.d t1, t1, t3 |
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| 78 | andi t0, t0, 0xff |
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| 79 | |
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| 80 | andi t1, t1, 0xff |
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| 81 | sub.d a0, t0, t1 |
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| 82 | jr ra |
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| 83 | nop |
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| 84 | |
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| 85 | L(ret0): |
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| 86 | move a0, zero |
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| 87 | jr ra |
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| 88 | nop |
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| 89 | nop |
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| 90 | |
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| 91 | L(unaligned): |
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| 92 | slt a6, a3, a2 |
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| 93 | xor t0, a0, a1 |
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| 94 | maskeqz t0, t0, a6 |
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| 95 | xor a0, a0, t0 |
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| 96 | |
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| 97 | |
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| 98 | xor a1, a1, t0 |
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| 99 | andi a2, a0, 0x7 |
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| 100 | andi a3, a1, 0x7 |
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| 101 | bstrins.d a0, zero, 2, 0 |
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| 102 | |
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| 103 | bstrins.d a1, zero, 2, 0 |
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| 104 | ld.d t4, a0, 0 |
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| 105 | ld.d t1, a1, 0 |
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| 106 | slli.d a2, a2, 3 |
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| 107 | |
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| 108 | slli.d a3, a3, 3 |
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| 109 | srl.d t0, t4, a2 |
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| 110 | srl.d t1, t1, a3 |
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| 111 | srl.d t5, t7, a3 |
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| 112 | |
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| 113 | orn t0, t0, t5 |
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| 114 | orn t1, t1, t5 |
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| 115 | bne t0, t1, L(not_equal) |
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| 116 | sll.d t5, t7, a2 |
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| 117 | |
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| 118 | |
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| 119 | sub.d a3, a2, a3 |
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| 120 | orn t4, t4, t5 |
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| 121 | sub.d a2, zero, a3 |
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| 122 | sub.d t2, t4, a4 |
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| 123 | |
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| 124 | andn t3, a5, t4 |
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| 125 | and t2, t2, t3 |
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| 126 | bnez t2, L(find_zero) |
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| 127 | L(un_loop): |
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| 128 | srl.d t5, t4, a3 |
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| 129 | |
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| 130 | ldx.d t4, a0, t8 |
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| 131 | ldx.d t1, a1, t8 |
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| 132 | addi.d t8, t8, 8 |
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| 133 | sll.d t0, t4, a2 |
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| 134 | |
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| 135 | or t0, t0, t5 |
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| 136 | bne t0, t1, L(not_equal) |
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| 137 | sub.d t2, t4, a4 |
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| 138 | andn t3, a5, t4 |
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| 139 | |
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| 140 | |
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| 141 | and t2, t2, t3 |
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| 142 | beqz t2, L(un_loop) |
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| 143 | L(find_zero): |
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| 144 | sub.d t2, t0, a4 |
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| 145 | andn t3, a5, t0 |
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| 146 | |
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| 147 | and t2, t2, t3 |
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| 148 | bnez t2, L(ret0) |
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| 149 | ldx.d t1, a1, t8 |
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| 150 | srl.d t0, t4, a3 |
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| 151 | |
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| 152 | L(not_equal): |
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| 153 | sub.d t2, t0, a4 |
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| 154 | andn t3, a5, t0 |
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| 155 | and t2, t2, t3 |
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| 156 | xor t3, t0, t1 |
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| 157 | |
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| 158 | or t2, t2, t3 |
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| 159 | L(un_end): |
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| 160 | ctz.d t3, t2 |
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| 161 | bstrins.d t3, zero, 2, 0 |
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| 162 | srl.d t0, t0, t3 |
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| 163 | |
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| 164 | |
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| 165 | srl.d t1, t1, t3 |
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| 166 | andi t0, t0, 0xff |
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| 167 | andi t1, t1, 0xff |
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| 168 | sub.d t2, t0, t1 |
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| 169 | |
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| 170 | |
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| 171 | sub.d t3, t1, t0 |
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| 172 | masknez t0, t2, a6 |
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| 173 | maskeqz t1, t3, a6 |
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| 174 | or a0, t0, t1 |
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| 175 | |
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| 176 | jr ra |
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| 177 | END(STRCMP_NAME) |
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| 178 | |
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| 179 | libc_hidden_builtin_def (STRCMP_NAME) |
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| 180 | |
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