46 lines
1.5 KiB
C
46 lines
1.5 KiB
C
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/* intel_init.c - SSE2 optimized filter functions
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*
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* Copyright (c) 2016 Google, Inc.
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*
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* This code is released under the libpng license.
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* For conditions of distribution and use, see the disclaimer
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* and license in png.h
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*/
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#include "../pngpriv.h"
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#ifdef PNG_READ_SUPPORTED
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#if PNG_INTEL_SSE_OPT > 0
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void
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png_init_filter_functions_sse2(png_structp pp, unsigned int bpp)
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{
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// The techniques used to implement each of these filters in SSE operate on
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// one pixel at a time.
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// So they generally speed up 3bpp images about 3x, 4bpp images about 4x.
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// They can scale up to 6 and 8 bpp images and down to 2 bpp images,
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// but they'd not likely have any benefit for 1bpp images.
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// Most of these can be implemented using only MMX and 64-bit registers,
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// but they end up a bit slower than using the equally-ubiquitous SSE2.
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if (bpp == 3)
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{
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pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub3_sse2;
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pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg3_sse2;
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pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =
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png_read_filter_row_paeth3_sse2;
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}
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else if (bpp == 4)
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{
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pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub4_sse2;
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pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg4_sse2;
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pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =
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png_read_filter_row_paeth4_sse2;
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}
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// No need optimize PNG_FILTER_VALUE_UP. The compiler should autovectorize.
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}
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#endif /* PNG_INTEL_SSE_OPT > 0 */
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#endif /* PNG_READ_SUPPORTED */
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