workbench/libs/png/intel/intel_init.c

   1
   2 /* intel_init.c - SSE2 optimized filter functions
   3  *
   4  * Copyright (c) 2018 Cosmin Truta
   5  * Copyright (c) 2016-2017 Glenn Randers-Pehrson
   6  * Written by Mike Klein and Matt Sarett, Google, Inc.
   7  * Derived from arm/arm_init.c
   8  *
   9  * This code is released under the libpng license.
  10  * For conditions of distribution and use, see the disclaimer
  11  * and license in png.h
  12  */
  13
  14 #include "../pngpriv.h"
  15
  16 #ifdef PNG_READ_SUPPORTED
  17 #if PNG_INTEL_SSE_IMPLEMENTATION > 0
  18
  19 void
  20 png_init_filter_functions_sse2(png_structp pp, unsigned int bpp)
  21 {
  22    /* The techniques used to implement each of these filters in SSE operate on
  23     * one pixel at a time.
  24     * So they generally speed up 3bpp images about 3x, 4bpp images about 4x.
  25     * They can scale up to 6 and 8 bpp images and down to 2 bpp images,
  26     * but they'd not likely have any benefit for 1bpp images.
  27     * Most of these can be implemented using only MMX and 64-bit registers,
  28     * but they end up a bit slower than using the equally-ubiquitous SSE2.
  29    */
  30    png_debug(1, "in png_init_filter_functions_sse2");
  31    if (bpp == 3)
  32    {
  33       pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub3_sse2;
  34       pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg3_sse2;
  35       pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =
  36          png_read_filter_row_paeth3_sse2;
  37    }
  38    else if (bpp == 4)
  39    {
  40       pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub4_sse2;
  41       pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg4_sse2;
  42       pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =
  43           png_read_filter_row_paeth4_sse2;
  44    }
  45
  46    /* No need optimize PNG_FILTER_VALUE_UP.  The compiler should
  47     * autovectorize.
  48     */
  49 }
  50
  51 #endif /* PNG_INTEL_SSE_IMPLEMENTATION > 0 */
  52 #endif /* PNG_READ_SUPPORTED */