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/*
* SPDX-FileCopyrightText: 2022 - 2023, Alejandro Colomar <alx@kernel.org>
* SPDX-License-Identifier: GPL-3.0-or-later
*/
#ifndef SHADOW_INCLUDE_LIB_BIT_H_
#define SHADOW_INCLUDE_LIB_BIT_H_
#include <config.h>
#include <limits.h>
#ifndef ULONG_WIDTH
#define ULONG_WIDTH (sizeof(unsigned long) * CHAR_BIT)
#endif
inline unsigned long bit_ceilul(unsigned long x);
inline unsigned long bit_ceil_wrapul(unsigned long x);
inline int leading_zerosul(unsigned long x);
/* stdc_bit_ceilul(3) */
inline unsigned long
bit_ceilul(unsigned long x)
{
return 1 + (ULONG_MAX >> leading_zerosul(x));
}
/* stdc_bit_ceilul(3), but wrap instead of having Undefined Behavior */
inline unsigned long
bit_ceil_wrapul(unsigned long x)
{
if (x == 0)
return 0;
return bit_ceilul(x);
}
/* stdc_leading_zerosul(3) */
inline int
leading_zerosul(unsigned long x)
{
return (x == 0) ? ULONG_WIDTH : __builtin_clzl(x);
}
#endif // include guard
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