firmware/asm/pcm-mixer.c

   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
  22 #if defined(CPU_ARM)
  23   #include "arm/pcm-mixer.c"
  24 #elif defined(CPU_COLDFIRE)
  25   #include "m68k/pcm-mixer.c"
  26 #else
  27
  28 #include "dsp-util.h" /* for clip_sample_16 */
  29 /* Mix channels' samples and apply gain factors */
  30 static FORCE_INLINE void mix_samples(int16_t *out,
  31                                      const int16_t *src0,
  32                                      int32_t src0_amp,
  33                                      const int16_t *src1,
  34                                      int32_t src1_amp,
  35                                      size_t size)
  36 {
  37     if (src0_amp == MIX_AMP_UNITY && src1_amp == MIX_AMP_UNITY)
  38     {
  39         /* Both are unity amplitude */
  40         do
  41         {
  42             int32_t l = *src0++ + *src1++;
  43             int32_t h = *src0++ + *src1++;
  44             *out++ = clip_sample_16(l);
  45             *out++ = clip_sample_16(h);
  46         }
  47         while ((size -= 2*sizeof(int16_t)) > 0);
  48     }
  49     else if (src0_amp != MIX_AMP_UNITY && src1_amp != MIX_AMP_UNITY)
  50     {
  51         /* Neither are unity amplitude */
  52         do
  53         {
  54             int32_t l = (*src0++ * src0_amp >> 16) + (*src1++ * src1_amp >> 16);
  55             int32_t h = (*src0++ * src0_amp >> 16) + (*src1++ * src1_amp >> 16);
  56             *out++ = clip_sample_16(l);
  57             *out++ = clip_sample_16(h);
  58         }
  59         while ((size -= 2*sizeof(int16_t)) > 0);
  60     }
  61     else
  62     {
  63         /* One is unity amplitude */
  64         if (src0_amp != MIX_AMP_UNITY)
  65         {
  66             /* Keep unity in src0, amp0 */
  67             const int16_t *src_tmp = src0;
  68             src0 = src1;
  69             src1 = src_tmp;
  70             src1_amp = src0_amp;
  71             src0_amp = MIX_AMP_UNITY;
  72         }
  73
  74         do
  75         {
  76             int32_t l = *src0++ + (*src1++ * src1_amp >> 16);
  77             int32_t h = *src0++ + (*src1++ * src1_amp >> 16);
  78             *out++ = clip_sample_16(l);
  79             *out++ = clip_sample_16(h);
  80         }
  81         while ((size -= 2*sizeof(int16_t)) > 0);
  82     }
  83 }
  84
  85 /* Write channel's samples and apply gain factor */
  86 static FORCE_INLINE void write_samples(int16_t *out,
  87                                        const int16_t *src,
  88                                        int32_t amp,
  89                                        size_t size)
  90 {
  91     if (LIKELY(amp == MIX_AMP_UNITY))
  92     {
  93         /* Channel is unity amplitude */
  94         memcpy(out, src, size);
  95     }
  96     else
  97     {
  98         /* Channel needs amplitude cut */
  99         do
 100         {
 101             int32_t l = *src++ * amp >> 16;
 102             int32_t h = *src++ * amp >> 16;
 103             *out++ = l;
 104             *out++ = h;
 105         }
 106         while ((size -= 2*sizeof(int16_t)) > 0);
 107     }
 108 }
 109
 110
 111 #endif /* CPU_* */
 112
 113 #ifndef mixer_buffer_callback_exit
 114 #define mixer_buffer_callback_exit() do{}while(0)
 115 #endif