xref: /external/chromium_org/third_party/libvpx/source/libvpx/vp9/common/x86/vp9_subpixel_8t_intrin_avx2.c

/*
 *  Copyright (c) 2010 The WebM project authors. All Rights Reserved.
 *
 *  Use of this source code is governed by a BSD-style license
 *  that can be found in the LICENSE 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.
 */

#include <immintrin.h>
#include "vpx_ports/mem.h"

// filters for 16_h8 and 16_v8
DECLARE_ALIGNED(32, static const uint8_t, filt1_global_avx2[32]) = {
  0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6, 7, 7, 8,
  0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6, 7, 7, 8
};

DECLARE_ALIGNED(32, static const uint8_t, filt2_global_avx2[32]) = {
  2, 3, 3, 4, 4, 5, 5, 6, 6, 7, 7, 8, 8, 9, 9, 10,
  2, 3, 3, 4, 4, 5, 5, 6, 6, 7, 7, 8, 8, 9, 9, 10
};

DECLARE_ALIGNED(32, static const uint8_t, filt3_global_avx2[32]) = {
  4, 5, 5, 6, 6, 7, 7, 8, 8, 9, 9, 10, 10, 11, 11, 12,
  4, 5, 5, 6, 6, 7, 7, 8, 8, 9, 9, 10, 10, 11, 11, 12
};

DECLARE_ALIGNED(32, static const uint8_t, filt4_global_avx2[32]) = {
  6, 7, 7, 8, 8, 9, 9, 10, 10, 11, 11, 12, 12, 13, 13, 14,
  6, 7, 7, 8, 8, 9, 9, 10, 10, 11, 11, 12, 12, 13, 13, 14
};

#if defined(__clang__)
# if __clang_major__ < 3 || (__clang_major__ == 3 && __clang_minor__ <= 3) || \
      (defined(__APPLE__) && __clang_major__ == 5 && __clang_minor__ == 0)
#  define MM256_BROADCASTSI128_SI256(x) \
       _mm_broadcastsi128_si256((__m128i const *)&(x))
# else  // clang > 3.3, and not 5.0 on macosx.
#  define MM256_BROADCASTSI128_SI256(x) _mm256_broadcastsi128_si256(x)
# endif  // clang <= 3.3
#elif defined(__GNUC__)
# if __GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ <= 6)
#  define MM256_BROADCASTSI128_SI256(x) \
       _mm_broadcastsi128_si256((__m128i const *)&(x))
# elif __GNUC__ == 4 && __GNUC_MINOR__ == 7
#  define MM256_BROADCASTSI128_SI256(x) _mm_broadcastsi128_si256(x)
# else  // gcc > 4.7
#  define MM256_BROADCASTSI128_SI256(x) _mm256_broadcastsi128_si256(x)
# endif  // gcc <= 4.6
#else  // !(gcc || clang)
# define MM256_BROADCASTSI128_SI256(x) _mm256_broadcastsi128_si256(x)
#endif  // __clang__

void vp9_filter_block1d16_h8_avx2(unsigned char *src_ptr,
                                  unsigned int src_pixels_per_line,
                                  unsigned char *output_ptr,
                                  unsigned int  output_pitch,
                                  unsigned int  output_height,
                                  int16_t *filter) {
  __m128i filtersReg;
  __m256i addFilterReg64, filt1Reg, filt2Reg, filt3Reg, filt4Reg;
  __m256i firstFilters, secondFilters, thirdFilters, forthFilters;
  __m256i srcRegFilt32b1_1, srcRegFilt32b2_1, srcRegFilt32b2, srcRegFilt32b3;
  __m256i srcReg32b1, srcReg32b2, filtersReg32;
  unsigned int i;
  unsigned int src_stride, dst_stride;

  // create a register with 0,64,0,64,0,64,0,64,0,64,0,64,0,64,0,64
  addFilterReg64 = _mm256_set1_epi32((int)0x0400040u);
  filtersReg = _mm_loadu_si128((__m128i *)filter);
  // converting the 16 bit (short) to 8 bit (byte) and have the same data
  // in both lanes of 128 bit register.
  filtersReg =_mm_packs_epi16(filtersReg, filtersReg);
  // have the same data in both lanes of a 256 bit register
  filtersReg32 = MM256_BROADCASTSI128_SI256(filtersReg);

  // duplicate only the first 16 bits (first and second byte)
  // across 256 bit register
  firstFilters = _mm256_shuffle_epi8(filtersReg32,
                 _mm256_set1_epi16(0x100u));
  // duplicate only the second 16 bits (third and forth byte)
  // across 256 bit register
  secondFilters = _mm256_shuffle_epi8(filtersReg32,
                  _mm256_set1_epi16(0x302u));
  // duplicate only the third 16 bits (fifth and sixth byte)
  // across 256 bit register
  thirdFilters = _mm256_shuffle_epi8(filtersReg32,
                 _mm256_set1_epi16(0x504u));
  // duplicate only the forth 16 bits (seventh and eighth byte)
  // across 256 bit register
  forthFilters = _mm256_shuffle_epi8(filtersReg32,
                 _mm256_set1_epi16(0x706u));

  filt1Reg = _mm256_load_si256((__m256i const *)filt1_global_avx2);
  filt2Reg = _mm256_load_si256((__m256i const *)filt2_global_avx2);
  filt3Reg = _mm256_load_si256((__m256i const *)filt3_global_avx2);
  filt4Reg = _mm256_load_si256((__m256i const *)filt4_global_avx2);

  // multiple the size of the source and destination stride by two
  src_stride = src_pixels_per_line << 1;
  dst_stride = output_pitch << 1;
  for (i = output_height; i > 1; i-=2) {
    // load the 2 strides of source
    srcReg32b1 = _mm256_castsi128_si256(
                 _mm_loadu_si128((__m128i *)(src_ptr-3)));
    srcReg32b1 = _mm256_inserti128_si256(srcReg32b1,
                 _mm_loadu_si128((__m128i *)
                 (src_ptr+src_pixels_per_line-3)), 1);

    // filter the source buffer
    srcRegFilt32b1_1= _mm256_shuffle_epi8(srcReg32b1, filt1Reg);
    srcRegFilt32b2= _mm256_shuffle_epi8(srcReg32b1, filt4Reg);

    // multiply 2 adjacent elements with the filter and add the result
    srcRegFilt32b1_1 = _mm256_maddubs_epi16(srcRegFilt32b1_1, firstFilters);
    srcRegFilt32b2 = _mm256_maddubs_epi16(srcRegFilt32b2, forthFilters);

    // add and saturate the results together
    srcRegFilt32b1_1 = _mm256_adds_epi16(srcRegFilt32b1_1, srcRegFilt32b2);

    // filter the source buffer
    srcRegFilt32b3= _mm256_shuffle_epi8(srcReg32b1, filt2Reg);
    srcRegFilt32b2= _mm256_shuffle_epi8(srcReg32b1, filt3Reg);

    // multiply 2 adjacent elements with the filter and add the result
    srcRegFilt32b3 = _mm256_maddubs_epi16(srcRegFilt32b3, secondFilters);
    srcRegFilt32b2 = _mm256_maddubs_epi16(srcRegFilt32b2, thirdFilters);

    // add and saturate the results together
    srcRegFilt32b1_1 = _mm256_adds_epi16(srcRegFilt32b1_1,
                       _mm256_min_epi16(srcRegFilt32b3, srcRegFilt32b2));

    // reading 2 strides of the next 16 bytes
    // (part of it was being read by earlier read)
    srcReg32b2 = _mm256_castsi128_si256(
                 _mm_loadu_si128((__m128i *)(src_ptr+5)));
    srcReg32b2 = _mm256_inserti128_si256(srcReg32b2,
                 _mm_loadu_si128((__m128i *)
                 (src_ptr+src_pixels_per_line+5)), 1);

    // add and saturate the results together
    srcRegFilt32b1_1 = _mm256_adds_epi16(srcRegFilt32b1_1,
                       _mm256_max_epi16(srcRegFilt32b3, srcRegFilt32b2));

    // filter the source buffer
    srcRegFilt32b2_1 = _mm256_shuffle_epi8(srcReg32b2, filt1Reg);
    srcRegFilt32b2 = _mm256_shuffle_epi8(srcReg32b2, filt4Reg);

    // multiply 2 adjacent elements with the filter and add the result
    srcRegFilt32b2_1 = _mm256_maddubs_epi16(srcRegFilt32b2_1, firstFilters);
    srcRegFilt32b2 = _mm256_maddubs_epi16(srcRegFilt32b2, forthFilters);

    // add and saturate the results together
    srcRegFilt32b2_1 = _mm256_adds_epi16(srcRegFilt32b2_1, srcRegFilt32b2);

    // filter the source buffer
    srcRegFilt32b3= _mm256_shuffle_epi8(srcReg32b2, filt2Reg);
    srcRegFilt32b2= _mm256_shuffle_epi8(srcReg32b2, filt3Reg);

    // multiply 2 adjacent elements with the filter and add the result
    srcRegFilt32b3 = _mm256_maddubs_epi16(srcRegFilt32b3, secondFilters);
    srcRegFilt32b2 = _mm256_maddubs_epi16(srcRegFilt32b2, thirdFilters);

    // add and saturate the results together
    srcRegFilt32b2_1 = _mm256_adds_epi16(srcRegFilt32b2_1,
                       _mm256_min_epi16(srcRegFilt32b3, srcRegFilt32b2));
    srcRegFilt32b2_1 = _mm256_adds_epi16(srcRegFilt32b2_1,
                       _mm256_max_epi16(srcRegFilt32b3, srcRegFilt32b2));


    srcRegFilt32b1_1 = _mm256_adds_epi16(srcRegFilt32b1_1, addFilterReg64);

    srcRegFilt32b2_1 = _mm256_adds_epi16(srcRegFilt32b2_1, addFilterReg64);

    // shift by 7 bit each 16 bit
    srcRegFilt32b1_1 = _mm256_srai_epi16(srcRegFilt32b1_1, 7);
    srcRegFilt32b2_1 = _mm256_srai_epi16(srcRegFilt32b2_1, 7);

    // shrink to 8 bit each 16 bits, the first lane contain the first
    // convolve result and the second lane contain the second convolve
    // result
    srcRegFilt32b1_1 = _mm256_packus_epi16(srcRegFilt32b1_1,
                                           srcRegFilt32b2_1);

    src_ptr+=src_stride;

    // save 16 bytes
    _mm_store_si128((__m128i*)output_ptr,
    _mm256_castsi256_si128(srcRegFilt32b1_1));

    // save the next 16 bits
    _mm_store_si128((__m128i*)(output_ptr+output_pitch),
    _mm256_extractf128_si256(srcRegFilt32b1_1, 1));
    output_ptr+=dst_stride;
  }

  // if the number of strides is odd.
  // process only 16 bytes
  if (i > 0) {
    __m128i srcReg1, srcReg2, srcRegFilt1_1, srcRegFilt2_1;
    __m128i srcRegFilt2, srcRegFilt3;

    srcReg1 = _mm_loadu_si128((__m128i *)(src_ptr-3));

    // filter the source buffer
    srcRegFilt1_1 = _mm_shuffle_epi8(srcReg1,
                    _mm256_castsi256_si128(filt1Reg));
    srcRegFilt2 = _mm_shuffle_epi8(srcReg1,
                  _mm256_castsi256_si128(filt4Reg));

    // multiply 2 adjacent elements with the filter and add the result
    srcRegFilt1_1 = _mm_maddubs_epi16(srcRegFilt1_1,
                    _mm256_castsi256_si128(firstFilters));
    srcRegFilt2 = _mm_maddubs_epi16(srcRegFilt2,
                  _mm256_castsi256_si128(forthFilters));

    // add and saturate the results together
    srcRegFilt1_1 = _mm_adds_epi16(srcRegFilt1_1, srcRegFilt2);

    // filter the source buffer
    srcRegFilt3= _mm_shuffle_epi8(srcReg1,
                 _mm256_castsi256_si128(filt2Reg));
    srcRegFilt2= _mm_shuffle_epi8(srcReg1,
                 _mm256_castsi256_si128(filt3Reg));

    // multiply 2 adjacent elements with the filter and add the result
    srcRegFilt3 = _mm_maddubs_epi16(srcRegFilt3,
                  _mm256_castsi256_si128(secondFilters));
    srcRegFilt2 = _mm_maddubs_epi16(srcRegFilt2,
                  _mm256_castsi256_si128(thirdFilters));

    // add and saturate the results together
    srcRegFilt1_1 = _mm_adds_epi16(srcRegFilt1_1,
                    _mm_min_epi16(srcRegFilt3, srcRegFilt2));

    // reading the next 16 bytes
    // (part of it was being read by earlier read)
    srcReg2 = _mm_loadu_si128((__m128i *)(src_ptr+5));

    // add and saturate the results together
    srcRegFilt1_1 = _mm_adds_epi16(srcRegFilt1_1,
                    _mm_max_epi16(srcRegFilt3, srcRegFilt2));

    // filter the source buffer
    srcRegFilt2_1 = _mm_shuffle_epi8(srcReg2,
                    _mm256_castsi256_si128(filt1Reg));
    srcRegFilt2 = _mm_shuffle_epi8(srcReg2,
                  _mm256_castsi256_si128(filt4Reg));

    // multiply 2 adjacent elements with the filter and add the result
    srcRegFilt2_1 = _mm_maddubs_epi16(srcRegFilt2_1,
                    _mm256_castsi256_si128(firstFilters));
    srcRegFilt2 = _mm_maddubs_epi16(srcRegFilt2,
                  _mm256_castsi256_si128(forthFilters));

    // add and saturate the results together
    srcRegFilt2_1 = _mm_adds_epi16(srcRegFilt2_1, srcRegFilt2);

    // filter the source buffer
    srcRegFilt3 = _mm_shuffle_epi8(srcReg2,
                  _mm256_castsi256_si128(filt2Reg));
    srcRegFilt2 = _mm_shuffle_epi8(srcReg2,
                  _mm256_castsi256_si128(filt3Reg));

    // multiply 2 adjacent elements with the filter and add the result
    srcRegFilt3 = _mm_maddubs_epi16(srcRegFilt3,
                  _mm256_castsi256_si128(secondFilters));
    srcRegFilt2 = _mm_maddubs_epi16(srcRegFilt2,
                  _mm256_castsi256_si128(thirdFilters));

    // add and saturate the results together
    srcRegFilt2_1 = _mm_adds_epi16(srcRegFilt2_1,
                    _mm_min_epi16(srcRegFilt3, srcRegFilt2));
    srcRegFilt2_1 = _mm_adds_epi16(srcRegFilt2_1,
                    _mm_max_epi16(srcRegFilt3, srcRegFilt2));


    srcRegFilt1_1 = _mm_adds_epi16(srcRegFilt1_1,
                    _mm256_castsi256_si128(addFilterReg64));

    srcRegFilt2_1 = _mm_adds_epi16(srcRegFilt2_1,
                    _mm256_castsi256_si128(addFilterReg64));

    // shift by 7 bit each 16 bit
    srcRegFilt1_1 = _mm_srai_epi16(srcRegFilt1_1, 7);
    srcRegFilt2_1 = _mm_srai_epi16(srcRegFilt2_1, 7);

    // shrink to 8 bit each 16 bits, the first lane contain the first
    // convolve result and the second lane contain the second convolve
    // result
    srcRegFilt1_1 = _mm_packus_epi16(srcRegFilt1_1, srcRegFilt2_1);

    // save 16 bytes
    _mm_store_si128((__m128i*)output_ptr, srcRegFilt1_1);
  }
}

void vp9_filter_block1d16_v8_avx2(unsigned char *src_ptr,
                                  unsigned int src_pitch,
                                  unsigned char *output_ptr,
                                  unsigned int out_pitch,
                                  unsigned int output_height,
                                  int16_t *filter) {
  __m128i filtersReg;
  __m256i addFilterReg64;
  __m256i srcReg32b1, srcReg32b2, srcReg32b3, srcReg32b4, srcReg32b5;
  __m256i srcReg32b6, srcReg32b7, srcReg32b8, srcReg32b9, srcReg32b10;
  __m256i srcReg32b11, srcReg32b12, filtersReg32;
  __m256i firstFilters, secondFilters, thirdFilters, forthFilters;
  unsigned int i;
  unsigned int src_stride, dst_stride;

  // create a register with 0,64,0,64,0,64,0,64,0,64,0,64,0,64,0,64
  addFilterReg64 = _mm256_set1_epi32((int)0x0400040u);
  filtersReg = _mm_loadu_si128((__m128i *)filter);
  // converting the 16 bit (short) to  8 bit (byte) and have the
  // same data in both lanes of 128 bit register.
  filtersReg =_mm_packs_epi16(filtersReg, filtersReg);
  // have the same data in both lanes of a 256 bit register
  filtersReg32 = MM256_BROADCASTSI128_SI256(filtersReg);

  // duplicate only the first 16 bits (first and second byte)
  // across 256 bit register
  firstFilters = _mm256_shuffle_epi8(filtersReg32,
                 _mm256_set1_epi16(0x100u));
  // duplicate only the second 16 bits (third and forth byte)
  // across 256 bit register
  secondFilters = _mm256_shuffle_epi8(filtersReg32,
                  _mm256_set1_epi16(0x302u));
  // duplicate only the third 16 bits (fifth and sixth byte)
  // across 256 bit register
  thirdFilters = _mm256_shuffle_epi8(filtersReg32,
                 _mm256_set1_epi16(0x504u));
  // duplicate only the forth 16 bits (seventh and eighth byte)
  // across 256 bit register
  forthFilters = _mm256_shuffle_epi8(filtersReg32,
                 _mm256_set1_epi16(0x706u));

  // multiple the size of the source and destination stride by two
  src_stride = src_pitch << 1;
  dst_stride = out_pitch << 1;

  // load 16 bytes 7 times in stride of src_pitch
  srcReg32b1 = _mm256_castsi128_si256(
               _mm_loadu_si128((__m128i *)(src_ptr)));
  srcReg32b2 = _mm256_castsi128_si256(
               _mm_loadu_si128((__m128i *)(src_ptr+src_pitch)));
  srcReg32b3 = _mm256_castsi128_si256(
               _mm_loadu_si128((__m128i *)(src_ptr+src_pitch*2)));
  srcReg32b4 = _mm256_castsi128_si256(
               _mm_loadu_si128((__m128i *)(src_ptr+src_pitch*3)));
  srcReg32b5 = _mm256_castsi128_si256(
               _mm_loadu_si128((__m128i *)(src_ptr+src_pitch*4)));
  srcReg32b6 = _mm256_castsi128_si256(
               _mm_loadu_si128((__m128i *)(src_ptr+src_pitch*5)));
  srcReg32b7 = _mm256_castsi128_si256(
               _mm_loadu_si128((__m128i *)(src_ptr+src_pitch*6)));

  // have each consecutive loads on the same 256 register
  srcReg32b1 = _mm256_inserti128_si256(srcReg32b1,
               _mm256_castsi256_si128(srcReg32b2), 1);
  srcReg32b2 = _mm256_inserti128_si256(srcReg32b2,
               _mm256_castsi256_si128(srcReg32b3), 1);
  srcReg32b3 = _mm256_inserti128_si256(srcReg32b3,
               _mm256_castsi256_si128(srcReg32b4), 1);
  srcReg32b4 = _mm256_inserti128_si256(srcReg32b4,
               _mm256_castsi256_si128(srcReg32b5), 1);
  srcReg32b5 = _mm256_inserti128_si256(srcReg32b5,
               _mm256_castsi256_si128(srcReg32b6), 1);
  srcReg32b6 = _mm256_inserti128_si256(srcReg32b6,
               _mm256_castsi256_si128(srcReg32b7), 1);

  // merge every two consecutive registers except the last one
  srcReg32b10 = _mm256_unpacklo_epi8(srcReg32b1, srcReg32b2);
  srcReg32b1 = _mm256_unpackhi_epi8(srcReg32b1, srcReg32b2);

  // save
  srcReg32b11 = _mm256_unpacklo_epi8(srcReg32b3, srcReg32b4);

  // save
  srcReg32b3 = _mm256_unpackhi_epi8(srcReg32b3, srcReg32b4);

  // save
  srcReg32b2 = _mm256_unpacklo_epi8(srcReg32b5, srcReg32b6);

  // save
  srcReg32b5 = _mm256_unpackhi_epi8(srcReg32b5, srcReg32b6);


  for (i = output_height; i > 1; i-=2) {
     // load the last 2 loads of 16 bytes and have every two
     // consecutive loads in the same 256 bit register
     srcReg32b8 = _mm256_castsi128_si256(
     _mm_loadu_si128((__m128i *)(src_ptr+src_pitch*7)));
     srcReg32b7 = _mm256_inserti128_si256(srcReg32b7,
     _mm256_castsi256_si128(srcReg32b8), 1);
     srcReg32b9 = _mm256_castsi128_si256(
     _mm_loadu_si128((__m128i *)(src_ptr+src_pitch*8)));
     srcReg32b8 = _mm256_inserti128_si256(srcReg32b8,
     _mm256_castsi256_si128(srcReg32b9), 1);

     // merge every two consecutive registers
     // save
     srcReg32b4 = _mm256_unpacklo_epi8(srcReg32b7, srcReg32b8);
     srcReg32b7 = _mm256_unpackhi_epi8(srcReg32b7, srcReg32b8);

     // multiply 2 adjacent elements with the filter and add the result
     srcReg32b10 = _mm256_maddubs_epi16(srcReg32b10, firstFilters);
     srcReg32b6 = _mm256_maddubs_epi16(srcReg32b4, forthFilters);

     // add and saturate the results together
     srcReg32b10 = _mm256_adds_epi16(srcReg32b10, srcReg32b6);

     // multiply 2 adjacent elements with the filter and add the result
     srcReg32b8 = _mm256_maddubs_epi16(srcReg32b11, secondFilters);
     srcReg32b12 = _mm256_maddubs_epi16(srcReg32b2, thirdFilters);

     // add and saturate the results together
     srcReg32b10 = _mm256_adds_epi16(srcReg32b10,
                   _mm256_min_epi16(srcReg32b8, srcReg32b12));
     srcReg32b10 = _mm256_adds_epi16(srcReg32b10,
                   _mm256_max_epi16(srcReg32b8, srcReg32b12));

     // multiply 2 adjacent elements with the filter and add the result
     srcReg32b1 = _mm256_maddubs_epi16(srcReg32b1, firstFilters);
     srcReg32b6 = _mm256_maddubs_epi16(srcReg32b7, forthFilters);

     srcReg32b1 = _mm256_adds_epi16(srcReg32b1, srcReg32b6);

     // multiply 2 adjacent elements with the filter and add the result
     srcReg32b8 = _mm256_maddubs_epi16(srcReg32b3, secondFilters);
     srcReg32b12 = _mm256_maddubs_epi16(srcReg32b5, thirdFilters);

     // add and saturate the results together
     srcReg32b1 = _mm256_adds_epi16(srcReg32b1,
                  _mm256_min_epi16(srcReg32b8, srcReg32b12));
     srcReg32b1 = _mm256_adds_epi16(srcReg32b1,
                  _mm256_max_epi16(srcReg32b8, srcReg32b12));

     srcReg32b10 = _mm256_adds_epi16(srcReg32b10, addFilterReg64);
     srcReg32b1 = _mm256_adds_epi16(srcReg32b1, addFilterReg64);

     // shift by 7 bit each 16 bit
     srcReg32b10 = _mm256_srai_epi16(srcReg32b10, 7);
     srcReg32b1 = _mm256_srai_epi16(srcReg32b1, 7);

     // shrink to 8 bit each 16 bits, the first lane contain the first
     // convolve result and the second lane contain the second convolve
     // result
     srcReg32b1 = _mm256_packus_epi16(srcReg32b10, srcReg32b1);

     src_ptr+=src_stride;

     // save 16 bytes
     _mm_store_si128((__m128i*)output_ptr,
     _mm256_castsi256_si128(srcReg32b1));

     // save the next 16 bits
     _mm_store_si128((__m128i*)(output_ptr+out_pitch),
     _mm256_extractf128_si256(srcReg32b1, 1));

     output_ptr+=dst_stride;

     // save part of the registers for next strides
     srcReg32b10 = srcReg32b11;
     srcReg32b1 = srcReg32b3;
     srcReg32b11 = srcReg32b2;
     srcReg32b3 = srcReg32b5;
     srcReg32b2 = srcReg32b4;
     srcReg32b5 = srcReg32b7;
     srcReg32b7 = srcReg32b9;
  }
  if (i > 0) {
    __m128i srcRegFilt1, srcRegFilt3, srcRegFilt4, srcRegFilt5;
    __m128i srcRegFilt6, srcRegFilt7, srcRegFilt8;
    // load the last 16 bytes
    srcRegFilt8 = _mm_loadu_si128((__m128i *)(src_ptr+src_pitch*7));

    // merge the last 2 results together
    srcRegFilt4 = _mm_unpacklo_epi8(
                  _mm256_castsi256_si128(srcReg32b7), srcRegFilt8);
    srcRegFilt7 = _mm_unpackhi_epi8(
                  _mm256_castsi256_si128(srcReg32b7), srcRegFilt8);

    // multiply 2 adjacent elements with the filter and add the result
    srcRegFilt1 = _mm_maddubs_epi16(_mm256_castsi256_si128(srcReg32b10),
                  _mm256_castsi256_si128(firstFilters));
    srcRegFilt4 = _mm_maddubs_epi16(srcRegFilt4,
                  _mm256_castsi256_si128(forthFilters));
    srcRegFilt3 = _mm_maddubs_epi16(_mm256_castsi256_si128(srcReg32b1),
                  _mm256_castsi256_si128(firstFilters));
    srcRegFilt7 = _mm_maddubs_epi16(srcRegFilt7,
                  _mm256_castsi256_si128(forthFilters));

    // add and saturate the results together
    srcRegFilt1 = _mm_adds_epi16(srcRegFilt1, srcRegFilt4);
    srcRegFilt3 = _mm_adds_epi16(srcRegFilt3, srcRegFilt7);


    // multiply 2 adjacent elements with the filter and add the result
    srcRegFilt4 = _mm_maddubs_epi16(_mm256_castsi256_si128(srcReg32b11),
                  _mm256_castsi256_si128(secondFilters));
    srcRegFilt5 = _mm_maddubs_epi16(_mm256_castsi256_si128(srcReg32b3),
                  _mm256_castsi256_si128(secondFilters));

    // multiply 2 adjacent elements with the filter and add the result
    srcRegFilt6 = _mm_maddubs_epi16(_mm256_castsi256_si128(srcReg32b2),
                  _mm256_castsi256_si128(thirdFilters));
    srcRegFilt7 = _mm_maddubs_epi16(_mm256_castsi256_si128(srcReg32b5),
                  _mm256_castsi256_si128(thirdFilters));

    // add and saturate the results together
    srcRegFilt1 = _mm_adds_epi16(srcRegFilt1,
                  _mm_min_epi16(srcRegFilt4, srcRegFilt6));
    srcRegFilt3 = _mm_adds_epi16(srcRegFilt3,
                  _mm_min_epi16(srcRegFilt5, srcRegFilt7));

    // add and saturate the results together
    srcRegFilt1 = _mm_adds_epi16(srcRegFilt1,
                  _mm_max_epi16(srcRegFilt4, srcRegFilt6));
    srcRegFilt3 = _mm_adds_epi16(srcRegFilt3,
                  _mm_max_epi16(srcRegFilt5, srcRegFilt7));


    srcRegFilt1 = _mm_adds_epi16(srcRegFilt1,
                  _mm256_castsi256_si128(addFilterReg64));
    srcRegFilt3 = _mm_adds_epi16(srcRegFilt3,
                  _mm256_castsi256_si128(addFilterReg64));

    // shift by 7 bit each 16 bit
    srcRegFilt1 = _mm_srai_epi16(srcRegFilt1, 7);
    srcRegFilt3 = _mm_srai_epi16(srcRegFilt3, 7);

    // shrink to 8 bit each 16 bits, the first lane contain the first
    // convolve result and the second lane contain the second convolve
    // result
    srcRegFilt1 = _mm_packus_epi16(srcRegFilt1, srcRegFilt3);

    // save 16 bytes
    _mm_store_si128((__m128i*)output_ptr, srcRegFilt1);
  }
}