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/*
* Copyright 2011 Tilera Corporation. All Rights Reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation, version 2.
*
* This program 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, GOOD TITLE or
* NON INFRINGEMENT. See the GNU General Public License for
* more details.
*/
#include <linux/types.h>
#include <linux/string.h>
#include <linux/module.h>
#undef strlen
size_t strlen(const char *s)
{
/* Get an aligned pointer. */
const uintptr_t s_int = (uintptr_t) s;
const uint64_t *p = (const uint64_t *)(s_int & -8);
/* Read the first word, but force bytes before the string to be nonzero.
* This expression works because we know shift counts are taken mod 64.
*/
uint64_t v = *p | ((1ULL << (s_int << 3)) - 1);
uint64_t bits;
while ((bits = __insn_v1cmpeqi(v, 0)) == 0)
v = *++p;
return ((const char *)p) + (__insn_ctz(bits) >> 3) - s;
}
EXPORT_SYMBOL(strlen);
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