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/* SPDX-License-Identifier: MIT */
/*
* Helper functions for manipulation & testing of integer values
* like zero or sign-extensions.
*
* Copyright (C) 2017 Luc Van Oostenryck
*
*/
#ifndef BITS_H
#define BITS_H
static inline unsigned long long sign_bit(unsigned size)
{
return 1ULL << (size - 1);
}
static inline unsigned long long sign_mask(unsigned size)
{
unsigned long long sbit = sign_bit(size);
return sbit - 1;
}
static inline unsigned long long bits_mask(unsigned size)
{
unsigned long long sbit = sign_bit(size);
return sbit | (sbit - 1);
}
static inline long long zero_extend(long long val, unsigned size)
{
return val & bits_mask(size);
}
static inline long long sign_extend(long long val, unsigned size)
{
if (val & sign_bit(size))
val |= ~sign_mask(size);
return val;
}
///
// sign extend @val but only if exactly representable
static inline long long sign_extend_safe(long long val, unsigned size)
{
unsigned long long mask = bits_mask(size);
if (!(val & ~mask))
val = sign_extend(val, size);
return val;
}
static inline long long bits_extend(long long val, unsigned size, int is_signed)
{
val = zero_extend(val, size);
if (is_signed)
val = sign_extend(val, size);
return val;
}
static inline int is_power_of_2(long long val)
{
return val && !(val & (val - 1));
}
///
// log base 2 of an exact power-of-2
static inline int log2_exact(unsigned long long val)
{
return 8 * sizeof(val) - __builtin_clzl(val) - 1;
}
#endif
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