/*************************************************************************** * __________ __ ___. * Open \______ \ ____ ____ | | _\_ |__ _______ ___ * Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ / * Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < < * Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \ * \/ \/ \/ \/ \/ * \$Id\$ * * Copyright (C) 2006 Jens Arnold * * Fixed point library for plugins * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version 2 * of the License, or (at your option) any later version. * * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY * KIND, either express or implied. * ****************************************************************************/ /** FIXED POINT MATH ROUTINES - USAGE * * - x and y arguments are fixed point integers * - fracbits is the number of fractional bits in the argument(s) * - functions return long fixed point integers with the specified number * of fractional bits unless otherwise specified * * Multiply two fixed point numbers: * fp_mul(x, y, fracbits) * * Divide two fixed point numbers: * fp_div(x, y, fracbits) * * Calculate sin and cos of an angle: * fp_sincos(phase, *cos) * where phase is a 32 bit unsigned integer with 0 representing 0 * and 0xFFFFFFFF representing 2*pi, and *cos is the address to * a long signed integer. Value returned is a long signed integer * from -0x80000000 to 0x7fffffff, representing -1 to 1 respectively. * That is, value is a fixed point integer with 31 fractional bits. * * Take square root of a fixed point number: * fp_sqrt(x, fracbits) * * Take the square root of an integer: * isqrt(x) * * Calculate sin or cos of an angle (very fast, from a table): * fp14_sin(angle) * fp14_cos(angle) * where angle is a non-fixed point integer in degrees. Value * returned is a fixed point integer with 14 fractional bits. * * Calculate the exponential of a fixed point integer * fp16_exp(x) * where x and the value returned are fixed point integers * with 16 fractional bits. * * Calculate the natural log of a positive fixed point integer * fp16_log(x) * where x and the value returned are fixed point integers * with 16 fractional bits. * * Calculate decibel equivalent of a gain factor: * fp_decibels(factor, fracbits) * where fracbits is in the range 12 to 22 (higher is better), * and factor is a positive fixed point integer. * * Calculate factor equivalent of a decibel value: * fp_factor(decibels, fracbits) * where fracbits is in the range 12 to 22 (lower is better), * and decibels is a fixed point integer. */ #ifndef FIXEDPOINT_H #define FIXEDPOINT_H #define fp_mul(x, y, z) (long)((((long long)(x)) * ((long long)(y))) >> (z)) #define fp_div(x, y, z) (long)((((long long)(x)) << (z)) / ((long long)(y))) long fp_sincos(unsigned long phase, long *cos); long fp_sqrt(long a, unsigned int fracbits); long fp14_cos(int val); long fp14_sin(int val); long fp16_log(int x); long fp16_exp(int x); unsigned long isqrt(unsigned long x); /* fast unsigned multiplication (16x16bit->32bit or 32x32bit->32bit, * whichever is faster for the architecture) */ #ifdef CPU_ARM #define FMULU(a, b) ((uint32_t) (((uint32_t) (a)) * ((uint32_t) (b)))) #else /* SH1, coldfire */ #define FMULU(a, b) ((uint32_t) (((uint16_t) (a)) * ((uint16_t) (b)))) #endif /** MODIFIED FROM replaygain.c */ #define FP_INF (0x7fffffff) #define FP_NEGINF -(0x7fffffff) /** FIXED POINT EXP10 * Return 10^x as FP integer. Argument is FP integer. */ long fp_exp10(long x, unsigned int fracbits); /** FIXED POINT LOG10 * Return log10(x) as FP integer. Argument is FP integer. */ long fp_log10(long n, unsigned int fracbits); /* fracbits in range 12 - 22 work well. Higher is better for * calculating dB, lower is better for calculating factor. */ /** CONVERT FACTOR TO DECIBELS */ long fp_decibels(unsigned long factor, unsigned int fracbits); /** CONVERT DECIBELS TO FACTOR */ long fp_factor(long decibels, unsigned int fracbits); #endif /* FIXEDPOINT_H */