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/* SPDX-License-Identifier: LGPL-2.1-or-later */
/*
* Provides fixed-point logarithm operations.
*
* Copyright (C) 2006 Christoph Pfister (christophpfister@gmail.com)
*/
#ifndef __LINUX_INT_LOG_H
#define __LINUX_INT_LOG_H
#include <linux/types.h>
/**
* intlog2 - computes log2 of a value; the result is shifted left by 24 bits
*
* @value: The value (must be != 0)
*
* to use rational values you can use the following method:
*
* intlog2(value) = intlog2(value * 2^x) - x * 2^24
*
* Some usecase examples:
*
* intlog2(8) will give 3 << 24 = 3 * 2^24
*
* intlog2(9) will give 3 << 24 + ... = 3.16... * 2^24
*
* intlog2(1.5) = intlog2(3) - 2^24 = 0.584... * 2^24
*
*
* return: log2(value) * 2^24
*/
extern unsigned int intlog2(u32 value);
/**
* intlog10 - computes log10 of a value; the result is shifted left by 24 bits
*
* @value: The value (must be != 0)
*
* to use rational values you can use the following method:
*
* intlog10(value) = intlog10(value * 10^x) - x * 2^24
*
* An usecase example:
*
* intlog10(1000) will give 3 << 24 = 3 * 2^24
*
* due to the implementation intlog10(1000) might be not exactly 3 * 2^24
*
* look at intlog2 for similar examples
*
* return: log10(value) * 2^24
*/
extern unsigned int intlog10(u32 value);
#endif
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