| 1 | /* Optimized version of the standard strncmp() function. |
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| 2 | This file is part of the GNU C Library. |
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| 3 | Copyright (C) 2000-2022 Free Software Foundation, Inc. |
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| 4 | |
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| 5 | The GNU C Library is free software; you can redistribute it and/or |
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| 6 | modify it under the terms of the GNU Lesser General Public |
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| 7 | License as published by the Free Software Foundation; either |
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| 8 | version 2.1 of the License, or (at your option) any later version. |
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| 9 | |
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| 10 | The GNU C Library is distributed in the hope that it will be useful, |
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| 11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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| 13 | Lesser General Public License for more details. |
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| 14 | |
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| 15 | You should have received a copy of the GNU Lesser General Public |
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| 16 | License along with the GNU C Library; if not, see |
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| 17 | <https://www.gnu.org/licenses/>. */ |
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| 18 | |
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| 19 | /* Return: the result of the comparison |
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| 20 | |
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| 21 | Inputs: |
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| 22 | in0: s1 |
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| 23 | in1: s2 |
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| 24 | in2: n |
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| 25 | |
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| 26 | Unlike memcmp(), this function is optimized for mismatches within the |
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| 27 | first few characters. */ |
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| 28 | |
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| 29 | #include <sysdep.h> |
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| 30 | #undef ret |
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| 31 | |
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| 32 | #define s1 in0 |
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| 33 | #define s2 in1 |
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| 34 | #define n in2 |
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| 35 | |
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| 36 | #define val1 r15 |
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| 37 | #define val2 r16 |
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| 38 | |
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| 39 | |
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| 40 | ENTRY(strncmp) |
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| 41 | alloc r2 = ar.pfs, 3, 0, 0, 0 |
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| 42 | mov ret0 = r0 |
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| 43 | cmp.eq p6, p0 = r0, r0 // set p6 |
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| 44 | cmp.eq p7, p0 = n, r0 // return immediately if n == 0 |
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| 45 | (p7) br.cond.spnt .restore_and_exit ;; |
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| 46 | .loop: |
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| 47 | ld1 val1 = [s1], 1 |
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| 48 | ld1 val2 = [s2], 1 |
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| 49 | adds n = -1, n // n-- |
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| 50 | ;; |
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| 51 | cmp.ne.and p6, p0 = val1, r0 |
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| 52 | cmp.ne.and p6, p0 = val2, r0 |
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| 53 | cmp.ne.and p6, p0 = n, r0 |
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| 54 | cmp.eq.and p6, p0 = val1, val2 |
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| 55 | (p6) br.cond.sptk .loop |
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| 56 | sub ret0 = val1, val2 |
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| 57 | .restore_and_exit: |
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| 58 | br.ret.sptk.many b0 |
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| 59 | END(strncmp) |
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| 60 | libc_hidden_builtin_def (strncmp) |
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| 61 | |
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