firmware/asm/beep.c

   1 /***************************************************************************
   2  *             __________               __   ___.
   3  *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
   4  *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
   5  *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
   6  *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
   7  *                     \/            \/     \/    \/            \/
   8  * $Id$
   9  *
  10  * Copyright (c) 2011 Michael Sevakis
  11  *
  12  * This program is free software; you can redistribute it and/or
  13  * modify it under the terms of the GNU General Public License
  14  * as published by the Free Software Foundation; either version 2
  15  * of the License, or (at your option) any later version.
  16  *
  17  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  18  * KIND, either express or implied.
  19  *
  20  ****************************************************************************/
  21 #if defined(CPU_ARM)
  22 #include "arm/beep.c"
  23 #elif defined (CPU_COLDFIRE)
  24 #include "m68k/beep.c"
  25 #else /* Generic */
  26
  27 /* Actually output samples into beep_buf */
  28 static FORCE_INLINE void beep_generate(int16_t *out, int count,
  29                                        uint32_t *phase, uint32_t step,
  30                                        int16_t amplitude)
  31 {
  32     uint32_t ph = *phase;
  33
  34     do
  35     {
  36         int16_t amp = amplitude;
  37
  38         if (ph > UINT32_MAX / 2)
  39             amp = -amp;
  40
  41         *out++ = amp;
  42         *out++ = amp;
  43
  44         ph += step;
  45     }
  46     while (--count > 0);
  47
  48     *phase = ph;
  49 }
  50
  51 #define BEEP_GENERIC
  52 #endif /* CPU_* */