intel_init.c (1792B)
1 /* intel_init.c - SSE2 optimized filter functions 2 * 3 * Copyright (c) 2018 Cosmin Truta 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 * This code is released under the libpng license. 9 * For conditions of distribution and use, see the disclaimer 10 * and license in png.h 11 */ 12 13 #include "../pngpriv.h" 14 15 #ifdef PNG_READ_SUPPORTED 16 #if PNG_INTEL_SSE_IMPLEMENTATION > 0 17 18 void 19 png_init_filter_functions_sse2(png_structp pp, unsigned int bpp) 20 { 21 /* The techniques used to implement each of these filters in SSE operate on 22 * one pixel at a time. 23 * So they generally speed up 3bpp images about 3x, 4bpp images about 4x. 24 * They can scale up to 6 and 8 bpp images and down to 2 bpp images, 25 * but they'd not likely have any benefit for 1bpp images. 26 * Most of these can be implemented using only MMX and 64-bit registers, 27 * but they end up a bit slower than using the equally-ubiquitous SSE2. 28 */ 29 png_debug(1, "in png_init_filter_functions_sse2"); 30 if (bpp == 3) 31 { 32 pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub3_sse2; 33 pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg3_sse2; 34 pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = 35 png_read_filter_row_paeth3_sse2; 36 } 37 else if (bpp == 4) 38 { 39 pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub4_sse2; 40 pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg4_sse2; 41 pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = 42 png_read_filter_row_paeth4_sse2; 43 } 44 45 /* No need optimize PNG_FILTER_VALUE_UP. The compiler should 46 * autovectorize. 47 */ 48 } 49 50 #endif /* PNG_INTEL_SSE_IMPLEMENTATION > 0 */ 51 #endif /* PNG_READ_SUPPORTED */