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xf.libdd93d52023-05-12 07:10:14 -07001/* Determine the length of a string. For Intel 80x86, x>=3.
2 Copyright (C) 1991-2016 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4 Contributed by Torbjorn Granlund (tege@sics.se).
5
6 The GNU C Library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Lesser General Public
8 License as published by the Free Software Foundation; either
9 version 2.1 of the License, or (at your option) any later version.
10
11 The GNU C Library is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
15
16 You should have received a copy of the GNU Lesser General Public
17 License along with the GNU C Library; if not, see
18 <http://www.gnu.org/licenses/>. */
19
20#include <string.h>
21
22size_t
23strlen (const char *str)
24{
25 int cnt;
26
27 asm("cld\n" /* Search forward. */
28 /* Some old versions of gas need `repne' instead of `repnz'. */
29 "repnz\n" /* Look for a zero byte. */
30 "scasb" /* %0, %1, %3 */ :
31 "=c" (cnt) : "D" (str), "0" (-1), "a" (0));
32
33 return -2 - cnt;
34}
35libc_hidden_builtin_def (strlen)