remoting/host/differ_block_sse2.cc

// Copyright (c) 2011 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#if defined(_MSC_VER)
#include <intrin.h>
#else
#include <mmintrin.h>
#include <emmintrin.h>
#endif

#include "remoting/host/differ_block.h"
#include "remoting/host/differ_block_internal.h"

namespace remoting {

extern int BlockDifference_SSE2_W16(const uint8* image1, const uint8* image2,
                                    int stride) {
  __m128i acc = _mm_setzero_si128();
  __m128i v0;
  __m128i v1;
  __m128i sad;
  for (int y = 0; y < kBlockSize; ++y) {
    const __m128i* i1 = reinterpret_cast<const __m128i*>(image1);
    const __m128i* i2 = reinterpret_cast<const __m128i*>(image2);
    v0 = _mm_loadu_si128(i1);
    v1 = _mm_loadu_si128(i2);
    sad = _mm_sad_epu8(v0, v1);
    acc = _mm_adds_epu16(acc, sad);
    v0 = _mm_loadu_si128(i1 + 1);
    v1 = _mm_loadu_si128(i2 + 1);
    sad = _mm_sad_epu8(v0, v1);
    acc = _mm_adds_epu16(acc, sad);
    v0 = _mm_loadu_si128(i1 + 2);
    v1 = _mm_loadu_si128(i2 + 2);
    sad = _mm_sad_epu8(v0, v1);
    acc = _mm_adds_epu16(acc, sad);
    v0 = _mm_loadu_si128(i1 + 3);
    v1 = _mm_loadu_si128(i2 + 3);
    sad = _mm_sad_epu8(v0, v1);
    acc = _mm_adds_epu16(acc, sad);

    // This essential means sad = acc >> 64. We only care about the lower 16
    // bits.
    sad = _mm_shuffle_epi32(acc, 0xEE);
    sad = _mm_adds_epu16(sad, acc);
    int diff = _mm_cvtsi128_si32(sad);
    if (diff)
      return 1;
    image1 += stride;
    image2 += stride;
  }
  return 0;
}

extern int BlockDifference_SSE2_W32(const uint8* image1, const uint8* image2,
                                    int stride) {
  __m128i acc = _mm_setzero_si128();
  __m128i v0;
  __m128i v1;
  __m128i sad;
  for (int y = 0; y < kBlockSize; ++y) {
    const __m128i* i1 = reinterpret_cast<const __m128i*>(image1);
    const __m128i* i2 = reinterpret_cast<const __m128i*>(image2);
    v0 = _mm_loadu_si128(i1);
    v1 = _mm_loadu_si128(i2);
    sad = _mm_sad_epu8(v0, v1);
    acc = _mm_adds_epu16(acc, sad);
    v0 = _mm_loadu_si128(i1 + 1);
    v1 = _mm_loadu_si128(i2 + 1);
    sad = _mm_sad_epu8(v0, v1);
    acc = _mm_adds_epu16(acc, sad);
    v0 = _mm_loadu_si128(i1 + 2);
    v1 = _mm_loadu_si128(i2 + 2);
    sad = _mm_sad_epu8(v0, v1);
    acc = _mm_adds_epu16(acc, sad);
    v0 = _mm_loadu_si128(i1 + 3);
    v1 = _mm_loadu_si128(i2 + 3);
    sad = _mm_sad_epu8(v0, v1);
    acc = _mm_adds_epu16(acc, sad);
    v0 = _mm_loadu_si128(i1 + 4);
    v1 = _mm_loadu_si128(i2 + 4);
    sad = _mm_sad_epu8(v0, v1);
    acc = _mm_adds_epu16(acc, sad);
    v0 = _mm_loadu_si128(i1 + 5);
    v1 = _mm_loadu_si128(i2 + 5);
    sad = _mm_sad_epu8(v0, v1);
    acc = _mm_adds_epu16(acc, sad);
    v0 = _mm_loadu_si128(i1 + 6);
    v1 = _mm_loadu_si128(i2 + 6);
    sad = _mm_sad_epu8(v0, v1);
    acc = _mm_adds_epu16(acc, sad);
    v0 = _mm_loadu_si128(i1 + 7);
    v1 = _mm_loadu_si128(i2 + 7);
    sad = _mm_sad_epu8(v0, v1);
    acc = _mm_adds_epu16(acc, sad);

    // This essential means sad = acc >> 64. We only care about the lower 16
    // bits.
    sad = _mm_shuffle_epi32(acc, 0xEE);
    sad = _mm_adds_epu16(sad, acc);
    int diff = _mm_cvtsi128_si32(sad);
    if (diff)
      return 1;
    image1 += stride;
    image2 += stride;
  }
  return 0;
}

}  // namespace remoting