text: 
  /* intel_init.c - SSE2 optimized filter functions
   *
   * Copyright (c) 2016-2017 Glenn Randers-Pehrson
   * Written by Mike Klein and Matt Sarett, Google, Inc.
   * Derived from arm/arm_init.c
   *
   * Last changed in libpng 1.6.29 [March 16, 2017]
   *
   * This code is released under the libpng license.
   * For conditions of distribution and use, see the disclaimer
   * and license in png.h
   */
  
  #include "../pngpriv.h"
  
  #ifdef PNG_READ_SUPPORTED
  #if PNG_INTEL_SSE_IMPLEMENTATION > 0
  
  void
  png_init_filter_functions_sse2(png_structp pp, unsigned int bpp)
  {
     /* The techniques used to implement each of these filters in SSE operate on
      * one pixel at a time.
      * So they generally speed up 3bpp images about 3x, 4bpp images about 4x.
      * They can scale up to 6 and 8 bpp images and down to 2 bpp images,
      * but they'd not likely have any benefit for 1bpp images.
      * Most of these can be implemented using only MMX and 64-bit registers,
      * but they end up a bit slower than using the equally-ubiquitous SSE2.
     */
     png_debug(1, "in png_init_filter_functions_sse2");
     if (bpp == 3)
     {
        pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub3_sse2;
        pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg3_sse2;
        pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =
           png_read_filter_row_paeth3_sse2;
     }
     else if (bpp == 4)
     {
        pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub4_sse2;
        pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg4_sse2;
        pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =
            png_read_filter_row_paeth4_sse2;
     }
  
     /* No need optimize PNG_FILTER_VALUE_UP.  The compiler should
      * autovectorize.
      */
  }
  
  #endif /* PNG_INTEL_SSE_IMPLEMENTATION > 0 */
  #endif /* PNG_READ_SUPPORTED */
  