blob 6670e597fb18c1eea2fd805b6de20b100f8d69cf
1 /***************************************************************************
2 * __________ __ ___.
3 * Open \______ \ ____ ____ | | _\_ |__ _______ ___
4 * Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
5 * Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
6 * Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
7 * \/ \/ \/ \/ \/
8 * \$Id\$
10 * Copyright (C) 2006 Jens Arnold
12 * Fixed point library for plugins
14 * This program is free software; you can redistribute it and/or
15 * modify it under the terms of the GNU General Public License
16 * as published by the Free Software Foundation; either version 2
17 * of the License, or (at your option) any later version.
19 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
20 * KIND, either express or implied.
22 ****************************************************************************/
24 /** APPS - FIXED POINT MATH ROUTINES - USAGE
26 * - x and y arguments are fixed point integers
27 * - fracbits is the number of fractional bits in the argument(s)
28 * - functions return long fixed point integers with the specified number
29 * of fractional bits unless otherwise specified
31 * Multiply two fixed point numbers:
32 * fp_mul(x, y, fracbits)
34 * Divide two fixed point numbers:
35 * fp_div(x, y, fracbits)
37 * Calculate decibel equivalent of a gain factor:
38 * fp_decibels(factor, fracbits)
39 * where fracbits is in the range 12 to 22 (higher is better),
40 * and factor is a positive fixed point integer.
42 * Calculate factor equivalent of a decibel value:
43 * fp_factor(decibels, fracbits)
44 * where fracbits is in the range 12 to 22 (lower is better),
45 * and decibels is a fixed point integer.
48 #ifndef _FIXEDPOINT_H_APPS
49 #define _FIXEDPOINT_H_APPS
51 #define fp_mul(x, y, z) (long)((((long long)(x)) * ((long long)(y))) >> (z))
52 #define fp_div(x, y, z) (long)((((long long)(x)) << (z)) / ((long long)(y)))
55 /** TAKEN FROM ORIGINAL fixedpoint.h */
56 long fp_sincos(unsigned long phase, long *cos);
59 /** MODIFIED FROM replaygain.c */
60 #define FP_INF (0x7fffffff)
61 #define FP_NEGINF -(0x7fffffff)
63 /* fracbits in range 12 - 22 work well. Higher is better for
64 * calculating dB, lower is better for calculating factor.
66 /* long fp_decibels(unsigned long factor, unsigned int fracbits); */
67 long fp_factor(long decibels, unsigned int fracbits);
69 #endif