cf19ba5599
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@22832 a1c6a512-1295-4272-9138-f99709370657
69 lines
2.5 KiB
C
69 lines
2.5 KiB
C
/***************************************************************************
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* __________ __ ___.
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* Open \______ \ ____ ____ | | _\_ |__ _______ ___
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* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
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* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
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* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
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* \/ \/ \/ \/ \/
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* $Id$
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*
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* Copyright (C) 2006 Jens Arnold
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*
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* Fixed point library for plugins
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
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* KIND, either express or implied.
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*
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****************************************************************************/
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/** APPS - FIXED POINT MATH ROUTINES - USAGE
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*
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* - x and y arguments are fixed point integers
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* - fracbits is the number of fractional bits in the argument(s)
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* - functions return long fixed point integers with the specified number
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* of fractional bits unless otherwise specified
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*
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* Multiply two fixed point numbers:
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* fp_mul(x, y, fracbits)
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*
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* Divide two fixed point numbers:
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* fp_div(x, y, fracbits)
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*
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* Calculate decibel equivalent of a gain factor:
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* fp_decibels(factor, fracbits)
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* where fracbits is in the range 12 to 22 (higher is better),
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* and factor is a positive fixed point integer.
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*
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* Calculate factor equivalent of a decibel value:
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* fp_factor(decibels, fracbits)
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* where fracbits is in the range 12 to 22 (lower is better),
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* and decibels is a fixed point integer.
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*/
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#ifndef _FIXEDPOINT_H_APPS
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#define _FIXEDPOINT_H_APPS
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#define fp_mul(x, y, z) (long)((((long long)(x)) * ((long long)(y))) >> (z))
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#define fp_div(x, y, z) (long)((((long long)(x)) << (z)) / ((long long)(y)))
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/** TAKEN FROM ORIGINAL fixedpoint.h */
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long fp_sincos(unsigned long phase, long *cos);
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/** MODIFIED FROM replaygain.c */
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#define FP_INF (0x7fffffff)
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#define FP_NEGINF -(0x7fffffff)
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/* fracbits in range 12 - 22 work well. Higher is better for
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* calculating dB, lower is better for calculating factor.
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*/
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/* long fp_decibels(unsigned long factor, unsigned int fracbits); */
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long fp_factor(long decibels, unsigned int fracbits);
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#endif
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