apps/plugins/lib/fixedpoint.h

   1 /***************************************************************************
   2  *             __________               __   ___.
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   8  * $Id$
   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 /** PLUGINS - 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  *  Calculate sin or cos of an angle (very fast, from a table):
  43  *      fp14_sin(angle)
  44  *      fp14_cos(angle)
  45  *          where angle is a non-fixed point integer in degrees.  Value
  46  *          returned is a fixed point integer with 14 fractional bits.
  47  *
  48  *  Calculate the natural log of a positive fixed point integer
  49  *      fp16_log(x)
  50  *          where x and the value returned are fixed point integers
  51  *          with 16 fractional bits.
  52  */
  53
  54 #ifndef _FIXEDPOINT_H_PLUGINS
  55 #define _FIXEDPOINT_H_PLUGINS
  56
  57 long fp_sincos(unsigned long phase, long *cos);
  58 long fp_sqrt(long a, unsigned int fracbits);
  59 long fp14_cos(int val);
  60 long fp14_sin(int val);
  61 long fp16_log(int x);
  62
  63 /* fast unsigned multiplication (16x16bit->32bit or 32x32bit->32bit,
  64  * whichever is faster for the architecture) */
  65 #ifdef CPU_ARM
  66 #define FMULU(a, b) ((uint32_t) (((uint32_t) (a)) * ((uint32_t) (b))))
  67 #else /* SH1, coldfire */
  68 #define FMULU(a, b) ((uint32_t) (((uint16_t) (a)) * ((uint16_t) (b))))
  69 #endif
  70
  71 #endif