mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-28 20:02:17 +00:00
![Andy Shevchenko](/assets/img/avatar_default.png)
Replace license boilerplate in udftime.c with SPDX identifier for LGPL-2.1-or-later. Acked-by: Mauro Carvalho Chehab <mchehab@kernel.org> Link: https://lore.kernel.org/r/20230619172019.21457-4-andriy.shevchenko@linux.intel.com Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://lore.kernel.org/r/20230703135211.87416-4-andriy.shevchenko@linux.intel.com Signed-off-by: Mark Brown <broonie@kernel.org>
56 lines
1.3 KiB
C
56 lines
1.3 KiB
C
/* 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
|