third_party/libwebp/dsp/lossless_enc_sse41.c

// Copyright 2015 Google Inc. All Rights Reserved.
//
// Use of this source code is governed by a BSD-style license
// that can be found in the COPYING file in the root of the source
// tree. An additional intellectual property rights grant can be found
// in the file PATENTS. All contributing project authors may
// be found in the AUTHORS file in the root of the source tree.
// -----------------------------------------------------------------------------
//
// SSE4.1 variant of methods for lossless encoder
//
// Author: Skal (pascal.massimino@gmail.com)

#include "./dsp.h"

#if defined(WEBP_USE_SSE41)
#include <assert.h>
#include <smmintrin.h>
#include "./lossless.h"

//------------------------------------------------------------------------------
// Subtract-Green Transform

static void SubtractGreenFromBlueAndRed(uint32_t* argb_data, int num_pixels) {
  int i;
  const __m128i kCstShuffle = _mm_set_epi8(-1, 13, -1, 13, -1, 9, -1, 9,
                                           -1,  5, -1,  5, -1, 1, -1, 1);
  for (i = 0; i + 4 <= num_pixels; i += 4) {
    const __m128i in = _mm_loadu_si128((__m128i*)&argb_data[i]);
    const __m128i in_0g0g = _mm_shuffle_epi8(in, kCstShuffle);
    const __m128i out = _mm_sub_epi8(in, in_0g0g);
    _mm_storeu_si128((__m128i*)&argb_data[i], out);
  }
  // fallthrough and finish off with plain-C
  VP8LSubtractGreenFromBlueAndRed_C(argb_data + i, num_pixels - i);
}

//------------------------------------------------------------------------------
// Entry point

extern void VP8LEncDspInitSSE41(void);

WEBP_TSAN_IGNORE_FUNCTION void VP8LEncDspInitSSE41(void) {
  VP8LSubtractGreenFromBlueAndRed = SubtractGreenFromBlueAndRed;
}

#else  // !WEBP_USE_SSE41

WEBP_DSP_INIT_STUB(VP8LEncDspInitSSE41)

#endif  // WEBP_USE_SSE41