firmware/export/dsp-util.h

   1 /***************************************************************************
   2  *             __________               __   ___.
   3  *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
   4  *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
   5  *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
   6  *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
   7  *                     \/            \/     \/    \/            \/
   8  * $Id$
   9  *
  10  * Copyright (C) 2011 by 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 #ifndef DSP_HELPER_H
  22 #define DSP_HELPER_H
  23
  24 /** Clip sample to signed 16 bit range **/
  25
  26 #ifdef CPU_ARM
  27 #if ARM_ARCH >= 6
  28 static FORCE_INLINE int32_t clip_sample_16(int32_t sample)
  29 {
  30     int32_t out;
  31         asm ("ssat %0, #16, %1"
  32         : "=r" (out) : "r"(sample));
  33     return out;
  34 }
  35 #define CLIP_SAMPLE_16_DEFINED
  36 #endif /* ARM_ARCH */
  37 #endif /* CPU_ARM */
  38
  39 #ifndef CLIP_SAMPLE_16_DEFINED
  40 /* Generic implementation */
  41 static FORCE_INLINE int32_t clip_sample_16(int32_t sample)
  42 {
  43     if ((int16_t)sample != sample)
  44         sample = 0x7fff ^ (sample >> 31);
  45     return sample;
  46 }
  47 #endif /* CLIP_SAMPLE_16_DEFINED */
  48
  49 #undef CLIP_SAMPLE_16_DEFINED
  50
  51 #endif /* DSP_HELPER_H */