apps/codecs/lib/fixedpoint.h

   1 /***************************************************************************
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   8  * $Id: fixedpoint.h -1   $
   9  *
  10  * Copyright (C) 2006 Jens Arnold
  11  *
  12  * Fixed point library for plugins
  13  *
  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.
  18  *
  19  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  20  * KIND, either express or implied.
  21  *
  22  ****************************************************************************/
  23
  24  /** CODECS - FIXED POINT MATH ROUTINES - USAGE
  25  *
  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
  30  *
  31  *  Calculate sin and cos of an angle:
  32  *      fp_sincos(phase, *cos)
  33  *          where phase is a 32 bit unsigned integer with 0 representing 0
  34  *          and 0xFFFFFFFF representing 2*pi, and *cos is the address to
  35  *          a long signed integer.  Value returned is a long signed integer
  36  *          from LONG_MIN to LONG_MAX, representing -1 to 1 respectively.
  37  *          That is, value is a fixed point integer with 31 fractional bits.
  38  *
  39  *  Take square root of a fixed point number:
  40  *      fp_sqrt(x, fracbits)
  41  *
  42  */
  43 #ifndef _FIXEDPOINT_H_CODECS
  44 #define _FIXEDPOINT_H_CODECS
  45
  46 long fp_sincos(unsigned long phase, long *cos);
  47 long fp_sqrt(long a, unsigned int fracbits);
  48
  49 #endif