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git.proxmox.com Git - mirror_ubuntu-eoan-kernel.git/blob - include/media/dvb_math.h
2 * dvb-math provides some complex fixed-point math
3 * operations shared between the dvb related stuff
5 * Copyright (C) 2006 Christoph Pfister (christophpfister@gmail.com)
7 * This library is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU Lesser General Public License as
9 * published by the Free Software Foundation; either version 2.1 of
10 * the License, or (at your option) any later version.
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU Lesser General Public License for more details.
21 #include <linux/types.h>
24 * intlog2 - computes log2 of a value; the result is shifted left by 24 bits
26 * @value: The value (must be != 0)
28 * to use rational values you can use the following method:
30 * intlog2(value) = intlog2(value * 2^x) - x * 2^24
32 * Some usecase examples:
34 * intlog2(8) will give 3 << 24 = 3 * 2^24
36 * intlog2(9) will give 3 << 24 + ... = 3.16... * 2^24
38 * intlog2(1.5) = intlog2(3) - 2^24 = 0.584... * 2^24
41 * return: log2(value) * 2^24
43 extern unsigned int intlog2(u32 value
);
46 * intlog10 - computes log10 of a value; the result is shifted left by 24 bits
48 * @value: The value (must be != 0)
50 * to use rational values you can use the following method:
52 * intlog10(value) = intlog10(value * 10^x) - x * 2^24
56 * intlog10(1000) will give 3 << 24 = 3 * 2^24
58 * due to the implementation intlog10(1000) might be not exactly 3 * 2^24
60 * look at intlog2 for similar examples
62 * return: log10(value) * 2^24
64 extern unsigned int intlog10(u32 value
);