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/***************************************************************************
* __________ __ ___.
* 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)
*
* 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);
long ipow(long x, long y);
/* 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 */
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