Line data    Source code

       1             : 
       2             : /* intel_init.c - SSE2 optimized filter functions
       3             :  *
       4             :  * Copyright (c) 2016-2017 Glenn Randers-Pehrson
       5             :  * Written by Mike Klein and Matt Sarett, Google, Inc.
       6             :  * Derived from arm/arm_init.c
       7             :  *
       8             :  * Last changed in libpng 1.6.29 [March 16, 2017]
       9             :  *
      10             :  * This code is released under the libpng license.
      11             :  * For conditions of distribution and use, see the disclaimer
      12             :  * and license in png.h
      13             :  */
      14             : 
      15             : #include "../pngpriv.h"
      16             : 
      17             : #ifdef PNG_READ_SUPPORTED
      18             : #if PNG_INTEL_SSE_IMPLEMENTATION > 0
      19             : 
      20             : void
      21           8 : png_init_filter_functions_sse2(png_structp pp, unsigned int bpp)
      22             : {
      23             :    /* The techniques used to implement each of these filters in SSE operate on
      24             :     * one pixel at a time.
      25             :     * So they generally speed up 3bpp images about 3x, 4bpp images about 4x.
      26             :     * They can scale up to 6 and 8 bpp images and down to 2 bpp images,
      27             :     * but they'd not likely have any benefit for 1bpp images.
      28             :     * Most of these can be implemented using only MMX and 64-bit registers,
      29             :     * but they end up a bit slower than using the equally-ubiquitous SSE2.
      30             :    */
      31             :    png_debug(1, "in png_init_filter_functions_sse2");
      32           8 :    if (bpp == 3)
      33             :    {
      34           0 :       pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub3_sse2;
      35           0 :       pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg3_sse2;
      36           0 :       pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =
      37             :          png_read_filter_row_paeth3_sse2;
      38             :    }
      39           8 :    else if (bpp == 4)
      40             :    {
      41           7 :       pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub4_sse2;
      42           7 :       pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg4_sse2;
      43           7 :       pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =
      44             :           png_read_filter_row_paeth4_sse2;
      45             :    }
      46             : 
      47             :    /* No need optimize PNG_FILTER_VALUE_UP.  The compiler should
      48             :     * autovectorize.
      49             :     */
      50           8 : }
      51             : 
      52             : #endif /* PNG_INTEL_SSE_IMPLEMENTATION > 0 */
      53             : #endif /* PNG_READ_SUPPORTED */