/* intel_init.c - SSE2 optimized filter functions * * Copyright (c) 2016 Google, Inc. * * Last changed in libpng 1.6.22 [(PENDING RELEASE)] * * 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. 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 */