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/*
* Copyright (c) 2014 Richard Braun.
*
* 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, either version 2 of the License, or
* (at your option) any later version.
*
* 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. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*
* Integer base 2 logarithm operations.
*/
#ifndef _KERN_LOG2_H
#define _KERN_LOG2_H
#include <kern/assert.h>
#ifdef __LP64__
#define LONG_BIT 64
#else /* __LP64__ */
#define LONG_BIT 32
#endif /* __LP64__ */
static inline unsigned int
ilog2(unsigned long x)
{
assert(x != 0);
return LONG_BIT - __builtin_clzl(x) - 1;
}
static inline unsigned int
iorder2(unsigned long size)
{
assert(size != 0);
if (size == 1)
return 0;
return ilog2(size - 1) + 1;
}
#endif /* _KERN_LOG2_H */
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