| /* Copyright (C) 2011-2014 Free Software Foundation, Inc. |
| This file is part of the GNU C Library. |
| Contributed by Chris Metcalf <cmetcalf@tilera.com>, 2011. |
| |
| The GNU C Library is free software; you can redistribute it and/or |
| modify it under the terms of the GNU Lesser General Public |
| License as published by the Free Software Foundation; either |
| version 2.1 of the License, or (at your option) any later version. |
| |
| The GNU C Library is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| Lesser General Public License for more details. |
| |
| You should have received a copy of the GNU Lesser General Public |
| License along with the GNU C Library. If not, see |
| <http://www.gnu.org/licenses/>. */ |
| |
| #include <string.h> |
| #include <stdint.h> |
| |
| size_t |
| strlen (const char *s) |
| { |
| /* Get an aligned pointer. */ |
| const uintptr_t s_int = (uintptr_t) s; |
| const uint32_t *p = (const uint32_t *) (s_int & -4); |
| |
| /* Read the first word, but force bytes before the string to be nonzero. |
| This expression works because we know shift counts are taken mod 32. */ |
| uint32_t v = *p | ((1 << (s_int << 3)) - 1); |
| |
| uint32_t bits; |
| while ((bits = __insn_seqb (v, 0)) == 0) |
| v = *++p; |
| |
| return ((const char *) p) + (__insn_ctz (bits) >> 3) - s; |
| } |
| libc_hidden_builtin_def (strlen) |
