gfx/2d/SwizzleSSSE3.cpp

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include "Swizzle.h"
   8
   9 #include <emmintrin.h>
  10 #include <tmmintrin.h>
  11
  12 namespace mozilla::gfx {
  13
  14 template <bool aSwapRB>
  15 void UnpackRowRGB24(const uint8_t* aSrc, uint8_t* aDst, int32_t aLength);
  16
  17 template <bool aSwapRB>
  18 void UnpackRowRGB24_SSSE3(const uint8_t* aSrc, uint8_t* aDst, int32_t aLength) {
  19   // Because this implementation will read an additional 4 bytes of data that
  20   // is ignored and masked over, we cannot use the accelerated version for the
  21   // last 1-5 pixels (3-15 bytes remaining) to guarantee we don't access memory
  22   // outside the buffer (we read in 16 byte chunks).
  23   if (aLength < 6) {
  24     UnpackRowRGB24<aSwapRB>(aSrc, aDst, aLength);
  25     return;
  26   }
  27
  28   // Because we are expanding, we can only process the data back to front in
  29   // case we are performing this in place.
  30   int32_t alignedRow = (aLength - 2) & ~3;
  31   int32_t remainder = aLength - alignedRow;
  32
  33   const uint8_t* src = aSrc + alignedRow * 3;
  34   uint8_t* dst = aDst + alignedRow * 4;
  35
  36   // Handle 2-5 remaining pixels.
  37   UnpackRowRGB24<aSwapRB>(src, dst, remainder);
  38
  39   __m128i mask;
  40   if (aSwapRB) {
  41     mask = _mm_set_epi8(15, 9, 10, 11, 14, 6, 7, 8, 13, 3, 4, 5, 12, 0, 1, 2);
  42   } else {
  43     mask = _mm_set_epi8(15, 11, 10, 9, 14, 8, 7, 6, 13, 5, 4, 3, 12, 2, 1, 0);
  44   }
  45
  46   __m128i alpha = _mm_set1_epi32(0xFF000000);
  47
  48   // Process all 4-pixel chunks as one vector.
  49   src -= 4 * 3;
  50   dst -= 4 * 4;
  51   while (src >= aSrc) {
  52     __m128i px = _mm_loadu_si128(reinterpret_cast<const __m128i*>(src));
  53     px = _mm_shuffle_epi8(px, mask);
  54     px = _mm_or_si128(px, alpha);
  55     _mm_storeu_si128(reinterpret_cast<__m128i*>(dst), px);
  56     src -= 4 * 3;
  57     dst -= 4 * 4;
  58   }
  59 }
  60
  61 // Force instantiation of swizzle variants here.
  62 template void UnpackRowRGB24_SSSE3<false>(const uint8_t*, uint8_t*, int32_t);
  63 template void UnpackRowRGB24_SSSE3<true>(const uint8_t*, uint8_t*, int32_t);
  64
  65 }  // namespace mozilla::gfx