libs/ardour/sse_functions_xmm.cc

   1 /*
   2     Copyright (C) 2007 Paul sDavis
   3     Written by Sampo Savolainen
   4
   5     This program is free software; you can redistribute it and/or modify
   6     it under the terms of the GNU General Public License as published by
   7     the Free Software Foundation; either version 2 of the License, or
   8     (at your option) any later version.
   9
  10     This program is distributed in the hope that it will be useful,
  11     but WITHOUT ANY WARRANTY; without even the implied warranty of
  12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13     GNU General Public License for more details.
  14
  15     You should have received a copy of the GNU General Public License
  16     along with this program; if not, write to the Free Software
  17     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  18
  19 */
  20
  21 #include <xmmintrin.h>
  22 #include "ardour/types.h"
  23
  24 void
  25 x86_sse_find_peaks(const ARDOUR::Sample* buf, ARDOUR::pframes_t nframes, float *min, float *max)
  26 {
  27         __m128 current_max, current_min, work;
  28
  29         // Load max and min values into all four slots of the XMM registers
  30         current_min = _mm_set1_ps(*min);
  31         current_max = _mm_set1_ps(*max);
  32
  33         // Work input until "buf" reaches 16 byte alignment
  34         while ( ((intptr_t)buf) % 16 != 0 && nframes > 0) {
  35
  36                 // Load the next float into the work buffer
  37                 work = _mm_set1_ps(*buf);
  38
  39                 current_min = _mm_min_ps(current_min, work);
  40                 current_max = _mm_max_ps(current_max, work);
  41
  42                 buf++;
  43                 nframes--;
  44         }
  45
  46         // use 64 byte prefetch for quadruple quads
  47         while (nframes >= 16) {
  48 #ifdef COMPILER_MSVC
  49                                 _mm_prefetch(((char*)buf+64), 0);  // A total guess! Assumed to be eqivalent to
  50 #else                                              // the line below but waiting to be tested !!
  51                 __builtin_prefetch(buf+64,0,0);
  52 #endif
  53                 work = _mm_load_ps(buf);
  54                 current_min = _mm_min_ps(current_min, work);
  55                 current_max = _mm_max_ps(current_max, work);
  56                 buf+=4;
  57                 work = _mm_load_ps(buf);
  58                 current_min = _mm_min_ps(current_min, work);
  59                 current_max = _mm_max_ps(current_max, work);
  60                 buf+=4;
  61                 work = _mm_load_ps(buf);
  62                 current_min = _mm_min_ps(current_min, work);
  63                 current_max = _mm_max_ps(current_max, work);
  64                 buf+=4;
  65                 work = _mm_load_ps(buf);
  66                 current_min = _mm_min_ps(current_min, work);
  67                 current_max = _mm_max_ps(current_max, work);
  68                 buf+=4;
  69                 nframes-=16;
  70         }
  71
  72         // work through aligned buffers
  73         while (nframes >= 4) {
  74
  75                 work = _mm_load_ps(buf);
  76
  77                 current_min = _mm_min_ps(current_min, work);
  78                 current_max = _mm_max_ps(current_max, work);
  79
  80                 buf+=4;
  81                 nframes-=4;
  82         }
  83
  84         // work through the rest < 4 samples
  85         while ( nframes > 0) {
  86
  87                 // Load the next float into the work buffer
  88                 work = _mm_set1_ps(*buf);
  89
  90                 current_min = _mm_min_ps(current_min, work);
  91                 current_max = _mm_max_ps(current_max, work);
  92
  93                 buf++;
  94                 nframes--;
  95         }
  96
  97         // Find min & max value in current_max through shuffle tricks
  98
  99         work = current_min;
 100         work = _mm_shuffle_ps(work, work, _MM_SHUFFLE(2, 3, 0, 1));
 101         work = _mm_min_ps (work, current_min);
 102         current_min = work;
 103         work = _mm_shuffle_ps(work, work, _MM_SHUFFLE(1, 0, 3, 2));
 104         work = _mm_min_ps (work, current_min);
 105
 106         _mm_store_ss(min, work);
 107
 108         work = current_max;
 109         work = _mm_shuffle_ps(work, work, _MM_SHUFFLE(2, 3, 0, 1));
 110         work = _mm_max_ps (work, current_max);
 111         current_max = work;
 112         work = _mm_shuffle_ps(work, work, _MM_SHUFFLE(1, 0, 3, 2));
 113         work = _mm_max_ps (work, current_max);
 114
 115         _mm_store_ss(max, work);
 116 }
 117
 118
 119