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 */