1 2 /* intel_init.c - SSE2 optimized filter functions 3 * 4 * Copyright (c) 2016 Google, Inc. 5 * Written by Mike Klein and Matt Sarett 6 * Derived from arm/arm_init.c, which was 7 * Copyright (c) 2014,2016 Glenn Randers-Pehrson 8 * 9 * Last changed in libpng 1.6.22 [May 26, 2016] 10 * 11 * This code is released under the libpng license. 12 * For conditions of distribution and use, see the disclaimer 13 * and license in png.h 14 */ 15 16 #include "../../pngpriv.h" 17 18 #ifdef PNG_READ_SUPPORTED 19 #if PNG_INTEL_SSE_IMPLEMENTATION > 0 20 21 void 22 png_init_filter_functions_sse2(png_structp pp, unsigned int bpp) 23 { 24 /* The techniques used to implement each of these filters in SSE operate on 25 * one pixel at a time. 26 * So they generally speed up 3bpp images about 3x, 4bpp images about 4x. 27 * They can scale up to 6 and 8 bpp images and down to 2 bpp images, 28 * but they'd not likely have any benefit for 1bpp images. 29 * Most of these can be implemented using only MMX and 64-bit registers, 30 * but they end up a bit slower than using the equally-ubiquitous SSE2. 31 */ 32 png_debug(1, "in png_init_filter_functions_sse2"); 33 if (bpp == 3) 34 { 35 pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub3_sse2; 36 pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg3_sse2; 37 pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = 38 png_read_filter_row_paeth3_sse2; 39 } 40 else if (bpp == 4) 41 { 42 pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub4_sse2; 43 pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg4_sse2; 44 pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = 45 png_read_filter_row_paeth4_sse2; 46 } 47 48 /* No need optimize PNG_FILTER_VALUE_UP. The compiler should 49 * autovectorize. 50 */ 51 } 52 53 #endif /* PNG_INTEL_SSE_IMPLEMENTATION > 0 */ 54 #endif /* PNG_READ_SUPPORTED */ 55
