| 1 | /* Optimized strncmp 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 STRNCMP __strncmp_aligned |
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| 26 | #else |
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| 27 | # define STRNCMP strncmp |
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| 28 | #endif |
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| 29 | |
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| 30 | LEAF(STRNCMP, 6) |
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| 31 | beqz a2, L(ret0) |
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| 32 | lu12i.w a5, 0x01010 |
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| 33 | andi a3, a0, 0x7 |
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| 34 | ori a5, a5, 0x101 |
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| 35 | |
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| 36 | andi a4, a1, 0x7 |
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| 37 | bstrins.d a5, a5, 63, 32 |
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| 38 | li.d t7, -1 |
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| 39 | li.d t8, 8 |
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| 40 | |
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| 41 | addi.d a2, a2, -1 |
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| 42 | slli.d a6, a5, 7 |
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| 43 | bne a3, a4, L(unaligned) |
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| 44 | bstrins.d a0, zero, 2, 0 |
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| 45 | |
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| 46 | bstrins.d a1, zero, 2, 0 |
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| 47 | ld.d t0, a0, 0 |
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| 48 | ld.d t1, a1, 0 |
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| 49 | slli.d t2, a3, 3 |
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| 50 | |
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| 51 | |
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| 52 | sub.d t5, t8, a3 |
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| 53 | srl.d t3, t7, t2 |
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| 54 | srl.d t0, t0, t2 |
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| 55 | srl.d t1, t1, t2 |
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| 56 | |
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| 57 | orn t0, t0, t3 |
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| 58 | orn t1, t1, t3 |
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| 59 | sub.d t2, t0, a5 |
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| 60 | andn t3, a6, t0 |
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| 61 | |
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| 62 | and t2, t2, t3 |
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| 63 | bne t0, t1, L(al_end) |
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| 64 | sltu t4, a2, t5 |
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| 65 | sub.d a2, a2, t5 |
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| 66 | |
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| 67 | L(al_loop): |
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| 68 | or t4, t2, t4 |
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| 69 | bnez t4, L(ret0) |
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| 70 | ldx.d t0, a0, t8 |
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| 71 | ldx.d t1, a1, t8 |
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| 72 | |
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| 73 | |
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| 74 | addi.d t8, t8, 8 |
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| 75 | sltui t4, a2, 8 |
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| 76 | addi.d a2, a2, -8 |
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| 77 | sub.d t2, t0, a5 |
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| 78 | |
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| 79 | andn t3, a6, t0 |
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| 80 | and t2, t2, t3 |
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| 81 | beq t0, t1, L(al_loop) |
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| 82 | addi.d a2, a2, 8 |
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| 83 | |
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| 84 | L(al_end): |
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| 85 | xor t3, t0, t1 |
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| 86 | or t2, t2, t3 |
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| 87 | ctz.d t2, t2 |
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| 88 | srli.d t4, t2, 3 |
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| 89 | |
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| 90 | bstrins.d t2, zero, 2, 0 |
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| 91 | srl.d t0, t0, t2 |
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| 92 | srl.d t1, t1, t2 |
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| 93 | andi t0, t0, 0xff |
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| 94 | |
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| 95 | |
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| 96 | andi t1, t1, 0xff |
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| 97 | sltu t2, a2, t4 |
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| 98 | sub.d a0, t0, t1 |
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| 99 | masknez a0, a0, t2 |
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| 100 | |
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| 101 | jr ra |
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| 102 | L(ret0): |
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| 103 | move a0, zero |
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| 104 | jr ra |
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| 105 | nop |
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| 106 | |
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| 107 | L(unaligned): |
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| 108 | slt a7, a4, a3 |
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| 109 | xor t0, a0, a1 |
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| 110 | maskeqz t0, t0, a7 |
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| 111 | xor a0, a0, t0 |
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| 112 | |
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| 113 | xor a1, a1, t0 |
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| 114 | andi a3, a0, 0x7 |
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| 115 | andi a4, a1, 0x7 |
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| 116 | bstrins.d a0, zero, 2, 0 |
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| 117 | |
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| 118 | |
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| 119 | bstrins.d a1, zero, 2, 0 |
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| 120 | ld.d t4, a0, 0 |
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| 121 | ld.d t1, a1, 0 |
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| 122 | slli.d t2, a3, 3 |
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| 123 | |
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| 124 | slli.d t3, a4, 3 |
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| 125 | srl.d t5, t7, t3 |
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| 126 | srl.d t0, t4, t2 |
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| 127 | srl.d t1, t1, t3 |
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| 128 | |
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| 129 | orn t0, t0, t5 |
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| 130 | orn t1, t1, t5 |
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| 131 | bne t0, t1, L(not_equal) |
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| 132 | sub.d t6, t8, a4 |
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| 133 | |
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| 134 | sub.d a4, t2, t3 |
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| 135 | sll.d t2, t7, t2 |
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| 136 | sub.d t5, t8, a3 |
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| 137 | orn t4, t4, t2 |
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| 138 | |
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| 139 | |
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| 140 | sub.d t2, t4, a5 |
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| 141 | andn t3, a6, t4 |
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| 142 | sltu t7, a2, t5 |
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| 143 | and t2, t2, t3 |
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| 144 | |
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| 145 | sub.d a3, zero, a4 |
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| 146 | or t2, t2, t7 |
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| 147 | bnez t2, L(un_end) |
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| 148 | sub.d t7, t5, t6 |
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| 149 | |
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| 150 | sub.d a2, a2, t5 |
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| 151 | sub.d t6, t8, t7 |
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| 152 | L(un_loop): |
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| 153 | srl.d t5, t4, a4 |
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| 154 | ldx.d t4, a0, t8 |
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| 155 | |
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| 156 | ldx.d t1, a1, t8 |
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| 157 | addi.d t8, t8, 8 |
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| 158 | sll.d t0, t4, a3 |
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| 159 | or t0, t0, t5 |
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| 160 | |
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| 161 | |
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| 162 | bne t0, t1, L(loop_not_equal) |
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| 163 | sub.d t2, t4, a5 |
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| 164 | andn t3, a6, t4 |
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| 165 | sltui t5, a2, 8 |
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| 166 | |
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| 167 | and t2, t2, t3 |
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| 168 | addi.d a2, a2, -8 |
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| 169 | or t3, t2, t5 |
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| 170 | beqz t3, L(un_loop) |
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| 171 | |
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| 172 | addi.d a2, a2, 8 |
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| 173 | L(un_end): |
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| 174 | sub.d t2, t0, a5 |
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| 175 | andn t3, a6, t0 |
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| 176 | sltu t5, a2, t6 |
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| 177 | |
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| 178 | and t2, t2, t3 |
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| 179 | or t2, t2, t5 |
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| 180 | bnez t2, L(ret0) |
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| 181 | ldx.d t1, a1, t8 |
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| 182 | |
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| 183 | |
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| 184 | srl.d t0, t4, a4 |
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| 185 | sub.d a2, a2, t6 |
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| 186 | L(not_equal): |
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| 187 | sub.d t2, t0, a5 |
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| 188 | andn t3, a6, t0 |
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| 189 | |
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| 190 | xor t4, t0, t1 |
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| 191 | and t2, t2, t3 |
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| 192 | or t2, t2, t4 |
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| 193 | ctz.d t2, t2 |
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| 194 | |
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| 195 | bstrins.d t2, zero, 2, 0 |
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| 196 | srli.d t4, t2, 3 |
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| 197 | srl.d t0, t0, t2 |
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| 198 | srl.d t1, t1, t2 |
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| 199 | |
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| 200 | andi t0, t0, 0xff |
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| 201 | andi t1, t1, 0xff |
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| 202 | sub.d t2, t0, t1 |
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| 203 | sub.d t3, t1, t0 |
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| 204 | |
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| 205 | |
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| 206 | masknez t0, t2, a7 |
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| 207 | maskeqz t1, t3, a7 |
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| 208 | sltu t2, a2, t4 |
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| 209 | or a0, t0, t1 |
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| 210 | |
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| 211 | masknez a0, a0, t2 |
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| 212 | jr ra |
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| 213 | L(loop_not_equal): |
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| 214 | add.d a2, a2, t7 |
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| 215 | b L(not_equal) |
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| 216 | END(STRNCMP) |
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| 217 | |
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| 218 | libc_hidden_builtin_def (STRNCMP) |
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| 219 | |
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