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/* Copyright (C) 2011 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)
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