tor-browser

The Tor Browser
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yuv_convert_mmx.cpp (1550B)


      1 // Copyright (c) 2010 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #include <mmintrin.h>
      6 #include "yuv_row.h"
      7 
      8 namespace mozilla {
      9 namespace gfx {
     10 
     11 // FilterRows combines two rows of the image using linear interpolation.
     12 // MMX version does 8 pixels at a time.
     13 void FilterRows_MMX(uint8_t* ybuf, const uint8_t* y0_ptr, const uint8_t* y1_ptr,
     14                    int source_width, int source_y_fraction) {
     15  __m64 zero = _mm_setzero_si64();
     16  __m64 y1_fraction = _mm_set1_pi16(source_y_fraction);
     17  __m64 y0_fraction = _mm_set1_pi16(256 - source_y_fraction);
     18 
     19  const __m64* y0_ptr64 = reinterpret_cast<const __m64*>(y0_ptr);
     20  const __m64* y1_ptr64 = reinterpret_cast<const __m64*>(y1_ptr);
     21  __m64* dest64 = reinterpret_cast<__m64*>(ybuf);
     22  __m64* end64 = reinterpret_cast<__m64*>(ybuf + source_width);
     23 
     24  do {
     25    __m64 y0 = *y0_ptr64++;
     26    __m64 y1 = *y1_ptr64++;
     27    __m64 y2 = _mm_unpackhi_pi8(y0, zero);
     28    __m64 y3 = _mm_unpackhi_pi8(y1, zero);
     29    y0 = _mm_unpacklo_pi8(y0, zero);
     30    y1 = _mm_unpacklo_pi8(y1, zero);
     31    y0 = _mm_mullo_pi16(y0, y0_fraction);
     32    y1 = _mm_mullo_pi16(y1, y1_fraction);
     33    y2 = _mm_mullo_pi16(y2, y0_fraction);
     34    y3 = _mm_mullo_pi16(y3, y1_fraction);
     35    y0 = _mm_add_pi16(y0, y1);
     36    y2 = _mm_add_pi16(y2, y3);
     37    y0 = _mm_srli_pi16(y0, 8);
     38    y2 = _mm_srli_pi16(y2, 8);
     39    y0 = _mm_packs_pu16(y0, y2);
     40    *dest64++ = y0;
     41  } while (dest64 < end64);
     42 }
     43 
     44 } // namespace gfx
     45 } // namespace mozilla