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 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 if (bpp == 3) 33 { 34 pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub3_sse2; 35 pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg3_sse2; 36 pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = 37 png_read_filter_row_paeth3_sse2; 38 } 39 else if (bpp == 4) 40 { 41 pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub4_sse2; 42 pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg4_sse2; 43 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 } 51 52 #endif /* PNG_INTEL_SSE_IMPLEMENTATION > 0 */ 53 #endif /* PNG_READ_SUPPORTED */ 54
