| 1 | /* Determine the length of a string. For Intel 80x86, x>=3. |
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| 2 | Copyright (C) 1991-2022 Free Software Foundation, Inc. |
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| 3 | This file is part of the GNU C Library. |
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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 | #include <string.h> |
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| 20 | |
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| 21 | size_t |
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| 22 | strlen (const char *str) |
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| 23 | { |
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| 24 | int cnt; |
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| 25 | |
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| 26 | asm("cld\n" /* Search forward. */ |
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| 27 | /* Some old versions of gas need `repne' instead of `repnz'. */ |
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| 28 | "repnz\n" /* Look for a zero byte. */ |
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| 29 | "scasb" /* %0, %1, %3 */ : |
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| 30 | "=c" (cnt) : "D" (str), "0" (-1), "a" (0)); |
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| 31 | |
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| 32 | return -2 - cnt; |
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| 33 | } |
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| 34 | libc_hidden_builtin_def (strlen) |
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| 35 | |
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