| /* |

| * dvb-math provides some complex fixed-point math |

| * operations shared between the dvb related stuff |

| * |

| * Copyright (C) 2006 Christoph Pfister (christophpfister@gmail.com) |

| * |

| * This library is free software; you can redistribute it and/or modify |

| * it under the terms of the GNU Lesser General Public License as |

| * published by the Free Software Foundation; either version 2.1 of |

| * the License, or (at your option) any later version. |

| * |

| * This program is distributed in the hope that it will be useful, |

| * but WITHOUT ANY WARRANTY; without even the implied warranty of |

| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |

| * GNU Lesser General Public License for more details. |

| * |

| * You should have received a copy of the GNU Lesser General Public |

| * License along with this library; if not, write to the Free Software |

| * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |

| */ |

| |

| #ifndef __DVB_MATH_H |

| #define __DVB_MATH_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 |