/*
 *  Copyright (c) 2023 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 <arm_neon.h>
#include <assert.h>

#include "./vpx_config.h"
#include "./vpx_dsp_rtcd.h"
#include "vpx/vpx_integer.h"
#include "vpx_dsp/arm/mem_neon.h"
#include "vpx_dsp/arm/transpose_neon.h"
#include "vpx_dsp/arm/vpx_convolve8_neon.h"
#include "vpx_dsp/vpx_filter.h"
#include "vpx_ports/mem.h"

DECLARE_ALIGNED(16, static const uint8_t, dot_prod_permute_tbl[48]) = {
  0, 1, 2,  3,  1, 2,  3,  4,  2,  3,  4,  5,  3,  4,  5,  6,
  4, 5, 6,  7,  5, 6,  7,  8,  6,  7,  8,  9,  7,  8,  9,  10,
  8, 9, 10, 11, 9, 10, 11, 12, 10, 11, 12, 13, 11, 12, 13, 14
};

DECLARE_ALIGNED(16, static const uint8_t, dot_prod_tran_concat_tbl[32]) = {
  0, 8,  16, 24, 1, 9,  17, 25, 2, 10, 18, 26, 3, 11, 19, 27,
  4, 12, 20, 28, 5, 13, 21, 29, 6, 14, 22, 30, 7, 15, 23, 31
};

DECLARE_ALIGNED(16, static const uint8_t, dot_prod_merge_block_tbl[48]) = {
  /* Shift left and insert new last column in transposed 4x4 block. */
  1, 2, 3, 16, 5, 6, 7, 20, 9, 10, 11, 24, 13, 14, 15, 28,
  /* Shift left and insert two new columns in transposed 4x4 block. */
  2, 3, 16, 17, 6, 7, 20, 21, 10, 11, 24, 25, 14, 15, 28, 29,
  /* Shift left and insert three new columns in transposed 4x4 block. */
  3, 16, 17, 18, 7, 20, 21, 22, 11, 24, 25, 26, 15, 28, 29, 30
};

void vpx_convolve8_2d_horiz_neon_i8mm(const uint8_t *src, ptrdiff_t src_stride,
                                      uint8_t *dst, ptrdiff_t dst_stride,
                                      const InterpKernel *filter, int x0_q4,
                                      int x_step_q4, int y0_q4, int y_step_q4,
                                      int w, int h) {
  const int8x8_t filters = vmovn_s16(vld1q_s16(filter[x0_q4]));
  uint8x16_t s0, s1, s2, s3;

  assert((intptr_t)dst % 4 == 0);
  assert(dst_stride % 4 == 0);
  assert(x_step_q4 == 16);
  assert(h % 4 == 3);

  (void)x_step_q4;
  (void)y0_q4;
  (void)y_step_q4;

  src -= 3;

  if (w == 4) {
    const uint8x16x2_t perm_tbl = vld1q_u8_x2(dot_prod_permute_tbl);
    int16x4_t d0, d1, d2, d3;
    uint8x8_t d01, d23;

    do {
      load_u8_16x4(src, src_stride, &s0, &s1, &s2, &s3);

      d0 = convolve8_4_usdot(s0, filters, perm_tbl);
      d1 = convolve8_4_usdot(s1, filters, perm_tbl);
      d2 = convolve8_4_usdot(s2, filters, perm_tbl);
      d3 = convolve8_4_usdot(s3, filters, perm_tbl);
      d01 = vqrshrun_n_s16(vcombine_s16(d0, d1), FILTER_BITS);
      d23 = vqrshrun_n_s16(vcombine_s16(d2, d3), FILTER_BITS);

      store_u8(dst + 0 * dst_stride, dst_stride, d01);
      store_u8(dst + 2 * dst_stride, dst_stride, d23);

      src += 4 * src_stride;
      dst += 4 * dst_stride;
      h -= 4;
    } while (h > 3);

    /* Process final three rows (h % 4 == 3). See vpx_convolve_neon.c for
     * further details on possible values of block height. */
    load_u8_16x3(src, src_stride, &s0, &s1, &s2);

    d0 = convolve8_4_usdot(s0, filters, perm_tbl);
    d1 = convolve8_4_usdot(s1, filters, perm_tbl);
    d2 = convolve8_4_usdot(s2, filters, perm_tbl);
    d01 = vqrshrun_n_s16(vcombine_s16(d0, d1), FILTER_BITS);
    d23 = vqrshrun_n_s16(vcombine_s16(d2, vdup_n_s16(0)), FILTER_BITS);

    store_u8(dst + 0 * dst_stride, dst_stride, d01);
    store_u8_4x1(dst + 2 * dst_stride, d23);
  } else {
    const uint8x16x3_t perm_tbl = vld1q_u8_x3(dot_prod_permute_tbl);
    const uint8_t *s;
    uint8_t *d;
    int width;
    uint8x8_t d0, d1, d2, d3;

    do {
      width = w;
      s = src;
      d = dst;
      do {
        load_u8_16x4(s, src_stride, &s0, &s1, &s2, &s3);

        d0 = convolve8_8_usdot(s0, filters, perm_tbl);
        d1 = convolve8_8_usdot(s1, filters, perm_tbl);
        d2 = convolve8_8_usdot(s2, filters, perm_tbl);
        d3 = convolve8_8_usdot(s3, filters, perm_tbl);

        store_u8_8x4(d, dst_stride, d0, d1, d2, d3);

        s += 8;
        d += 8;
        width -= 8;
      } while (width > 0);
      src += 4 * src_stride;
      dst += 4 * dst_stride;
      h -= 4;
    } while (h > 3);

    /* Process final three rows (h % 4 == 3). See vpx_convolve_neon.c for
     * further details on possible values of block height. */
    width = w;
    s = src;
    d = dst;
    do {
      load_u8_16x3(s, src_stride, &s0, &s1, &s2);

      d0 = convolve8_8_usdot(s0, filters, perm_tbl);
      d1 = convolve8_8_usdot(s1, filters, perm_tbl);
      d2 = convolve8_8_usdot(s2, filters, perm_tbl);

      store_u8_8x3(d, dst_stride, d0, d1, d2);

      s += 8;
      d += 8;
      width -= 8;
    } while (width > 0);
  }
}

void vpx_convolve8_horiz_neon_i8mm(const uint8_t *src, ptrdiff_t src_stride,
                                   uint8_t *dst, ptrdiff_t dst_stride,
                                   const InterpKernel *filter, int x0_q4,
                                   int x_step_q4, int y0_q4, int y_step_q4,
                                   int w, int h) {
  const int8x8_t filters = vmovn_s16(vld1q_s16(filter[x0_q4]));
  uint8x16_t s0, s1, s2, s3;

  assert((intptr_t)dst % 4 == 0);
  assert(dst_stride % 4 == 0);
  assert(x_step_q4 == 16);

  (void)x_step_q4;
  (void)y0_q4;
  (void)y_step_q4;

  src -= 3;

  if (w == 4) {
    const uint8x16x2_t perm_tbl = vld1q_u8_x2(dot_prod_permute_tbl);
    do {
      int16x4_t t0, t1, t2, t3;
      uint8x8_t d01, d23;

      load_u8_16x4(src, src_stride, &s0, &s1, &s2, &s3);

      t0 = convolve8_4_usdot(s0, filters, perm_tbl);
      t1 = convolve8_4_usdot(s1, filters, perm_tbl);
      t2 = convolve8_4_usdot(s2, filters, perm_tbl);
      t3 = convolve8_4_usdot(s3, filters, perm_tbl);
      d01 = vqrshrun_n_s16(vcombine_s16(t0, t1), FILTER_BITS);
      d23 = vqrshrun_n_s16(vcombine_s16(t2, t3), FILTER_BITS);

      store_u8(dst + 0 * dst_stride, dst_stride, d01);
      store_u8(dst + 2 * dst_stride, dst_stride, d23);

      src += 4 * src_stride;
      dst += 4 * dst_stride;
      h -= 4;
    } while (h != 0);
  } else {
    const uint8x16x3_t perm_tbl = vld1q_u8_x3(dot_prod_permute_tbl);
    const uint8_t *s;
    uint8_t *d;
    int width;
    uint8x8_t d0, d1, d2, d3;

    do {
      width = w;
      s = src;
      d = dst;
      do {
        load_u8_16x4(s, src_stride, &s0, &s1, &s2, &s3);

        d0 = convolve8_8_usdot(s0, filters, perm_tbl);
        d1 = convolve8_8_usdot(s1, filters, perm_tbl);
        d2 = convolve8_8_usdot(s2, filters, perm_tbl);
        d3 = convolve8_8_usdot(s3, filters, perm_tbl);

        store_u8_8x4(d, dst_stride, d0, d1, d2, d3);

        s += 8;
        d += 8;
        width -= 8;
      } while (width != 0);
      src += 4 * src_stride;
      dst += 4 * dst_stride;
      h -= 4;
    } while (h != 0);
  }
}

void vpx_convolve8_avg_horiz_neon_i8mm(const uint8_t *src, ptrdiff_t src_stride,
                                       uint8_t *dst, ptrdiff_t dst_stride,
                                       const InterpKernel *filter, int x0_q4,
                                       int x_step_q4, int y0_q4, int y_step_q4,
                                       int w, int h) {
  const int8x8_t filters = vmovn_s16(vld1q_s16(filter[x0_q4]));
  uint8x16_t s0, s1, s2, s3;

  assert((intptr_t)dst % 4 == 0);
  assert(dst_stride % 4 == 0);
  assert(x_step_q4 == 16);

  (void)x_step_q4;
  (void)y0_q4;
  (void)y_step_q4;

  src -= 3;

  if (w == 4) {
    const uint8x16x2_t perm_tbl = vld1q_u8_x2(dot_prod_permute_tbl);
    do {
      int16x4_t t0, t1, t2, t3;
      uint8x8_t d01, d23, dd01, dd23;

      load_u8_16x4(src, src_stride, &s0, &s1, &s2, &s3);

      t0 = convolve8_4_usdot(s0, filters, perm_tbl);
      t1 = convolve8_4_usdot(s1, filters, perm_tbl);
      t2 = convolve8_4_usdot(s2, filters, perm_tbl);
      t3 = convolve8_4_usdot(s3, filters, perm_tbl);
      d01 = vqrshrun_n_s16(vcombine_s16(t0, t1), FILTER_BITS);
      d23 = vqrshrun_n_s16(vcombine_s16(t2, t3), FILTER_BITS);

      dd01 = load_u8(dst + 0 * dst_stride, dst_stride);
      dd23 = load_u8(dst + 2 * dst_stride, dst_stride);

      d01 = vrhadd_u8(d01, dd01);
      d23 = vrhadd_u8(d23, dd23);

      store_u8(dst + 0 * dst_stride, dst_stride, d01);
      store_u8(dst + 2 * dst_stride, dst_stride, d23);

      src += 4 * src_stride;
      dst += 4 * dst_stride;
      h -= 4;
    } while (h != 0);
  } else {
    const uint8x16x3_t perm_tbl = vld1q_u8_x3(dot_prod_permute_tbl);
    const uint8_t *s;
    uint8_t *d;
    int width;
    uint8x8_t d0, d1, d2, d3, dd0, dd1, dd2, dd3;

    do {
      width = w;
      s = src;
      d = dst;
      do {
        load_u8_16x4(s, src_stride, &s0, &s1, &s2, &s3);

        d0 = convolve8_8_usdot(s0, filters, perm_tbl);
        d1 = convolve8_8_usdot(s1, filters, perm_tbl);
        d2 = convolve8_8_usdot(s2, filters, perm_tbl);
        d3 = convolve8_8_usdot(s3, filters, perm_tbl);

        load_u8_8x4(d, dst_stride, &dd0, &dd1, &dd2, &dd3);

        d0 = vrhadd_u8(d0, dd0);
        d1 = vrhadd_u8(d1, dd1);
        d2 = vrhadd_u8(d2, dd2);
        d3 = vrhadd_u8(d3, dd3);

        store_u8_8x4(d, dst_stride, d0, d1, d2, d3);

        s += 8;
        d += 8;
        width -= 8;
      } while (width != 0);
      src += 4 * src_stride;
      dst += 4 * dst_stride;
      h -= 4;
    } while (h != 0);
  }
}

static INLINE void transpose_concat_4x4(uint8x8_t a0, uint8x8_t a1,
                                        uint8x8_t a2, uint8x8_t a3,
                                        uint8x16_t *b,
                                        const uint8x16_t permute_tbl) {
  /* Transpose 8-bit elements and concatenate result rows as follows:
   * a0: 00, 01, 02, 03, XX, XX, XX, XX
   * a1: 10, 11, 12, 13, XX, XX, XX, XX
   * a2: 20, 21, 22, 23, XX, XX, XX, XX
   * a3: 30, 31, 32, 33, XX, XX, XX, XX
   *
   * b: 00, 10, 20, 30, 01, 11, 21, 31, 02, 12, 22, 32, 03, 13, 23, 33
   *
   * The 'permute_tbl' is always 'dot_prod_tran_concat_tbl' above. Passing it
   * as an argument is preferable to loading it directly from memory as this
   * inline helper is called many times from the same parent function.
   */

  uint8x16x2_t samples = { { vcombine_u8(a0, a1), vcombine_u8(a2, a3) } };
  *b = vqtbl2q_u8(samples, permute_tbl);
}

static INLINE void transpose_concat_8x4(uint8x8_t a0, uint8x8_t a1,
                                        uint8x8_t a2, uint8x8_t a3,
                                        uint8x16_t *b0, uint8x16_t *b1,
                                        const uint8x16x2_t permute_tbl) {
  /* Transpose 8-bit elements and concatenate result rows as follows:
   * a0: 00, 01, 02, 03, 04, 05, 06, 07
   * a1: 10, 11, 12, 13, 14, 15, 16, 17
   * a2: 20, 21, 22, 23, 24, 25, 26, 27
   * a3: 30, 31, 32, 33, 34, 35, 36, 37
   *
   * b0: 00, 10, 20, 30, 01, 11, 21, 31, 02, 12, 22, 32, 03, 13, 23, 33
   * b1: 04, 14, 24, 34, 05, 15, 25, 35, 06, 16, 26, 36, 07, 17, 27, 37
   *
   * The 'permute_tbl' is always 'dot_prod_tran_concat_tbl' above. Passing it
   * as an argument is preferable to loading it directly from memory as this
   * inline helper is called many times from the same parent function.
   */

  uint8x16x2_t samples = { { vcombine_u8(a0, a1), vcombine_u8(a2, a3) } };
  *b0 = vqtbl2q_u8(samples, permute_tbl.val[0]);
  *b1 = vqtbl2q_u8(samples, permute_tbl.val[1]);
}

void vpx_convolve8_vert_neon_i8mm(const uint8_t *src, ptrdiff_t src_stride,
                                  uint8_t *dst, ptrdiff_t dst_stride,
                                  const InterpKernel *filter, int x0_q4,
                                  int x_step_q4, int y0_q4, int y_step_q4,
                                  int w, int h) {
  const int8x8_t filters = vmovn_s16(vld1q_s16(filter[y0_q4]));
  const uint8x16x3_t merge_block_tbl = vld1q_u8_x3(dot_prod_merge_block_tbl);
  uint8x8_t s0, s1, s2, s3, s4, s5, s6, s7, s8, s9, s10;
  uint8x16x2_t samples_LUT;

  assert((intptr_t)dst % 4 == 0);
  assert(dst_stride % 4 == 0);
  assert(y_step_q4 == 16);

  (void)x0_q4;
  (void)x_step_q4;
  (void)y_step_q4;

  src -= 3 * src_stride;

  if (w == 4) {
    const uint8x16_t tran_concat_tbl = vld1q_u8(dot_prod_tran_concat_tbl);
    uint8x16_t s0123, s1234, s2345, s3456, s4567, s5678, s6789, s78910;
    int16x4_t d0, d1, d2, d3;
    uint8x8_t d01, d23;

    load_u8_8x7(src, src_stride, &s0, &s1, &s2, &s3, &s4, &s5, &s6);
    src += 7 * src_stride;

    s7 = vdup_n_u8(0);
    s8 = vdup_n_u8(0);
    s9 = vdup_n_u8(0);

    /* This operation combines a conventional transpose and the sample permute
     * (see horizontal case) required before computing the dot product.
     */
    transpose_concat_4x4(s0, s1, s2, s3, &s0123, tran_concat_tbl);
    transpose_concat_4x4(s1, s2, s3, s4, &s1234, tran_concat_tbl);
    transpose_concat_4x4(s2, s3, s4, s5, &s2345, tran_concat_tbl);
    transpose_concat_4x4(s3, s4, s5, s6, &s3456, tran_concat_tbl);
    transpose_concat_4x4(s4, s5, s6, s7, &s4567, tran_concat_tbl);
    transpose_concat_4x4(s5, s6, s7, s8, &s5678, tran_concat_tbl);
    transpose_concat_4x4(s6, s7, s8, s9, &s6789, tran_concat_tbl);

    do {
      load_u8_8x4(src, src_stride, &s7, &s8, &s9, &s10);

      transpose_concat_4x4(s7, s8, s9, s10, &s78910, tran_concat_tbl);

      /* Merge new data into block from previous iteration. */
      samples_LUT.val[0] = s3456;
      samples_LUT.val[1] = s78910;
      s4567 = vqtbl2q_u8(samples_LUT, merge_block_tbl.val[0]);
      s5678 = vqtbl2q_u8(samples_LUT, merge_block_tbl.val[1]);
      s6789 = vqtbl2q_u8(samples_LUT, merge_block_tbl.val[2]);

      d0 = convolve8_4_usdot_partial(s0123, s4567, filters);
      d1 = convolve8_4_usdot_partial(s1234, s5678, filters);
      d2 = convolve8_4_usdot_partial(s2345, s6789, filters);
      d3 = convolve8_4_usdot_partial(s3456, s78910, filters);
      d01 = vqrshrun_n_s16(vcombine_s16(d0, d1), FILTER_BITS);
      d23 = vqrshrun_n_s16(vcombine_s16(d2, d3), FILTER_BITS);

      store_u8(dst + 0 * dst_stride, dst_stride, d01);
      store_u8(dst + 2 * dst_stride, dst_stride, d23);

      /* Prepare block for next iteration - re-using as much as possible. */
      /* Shuffle everything up four rows. */
      s0123 = s4567;
      s1234 = s5678;
      s2345 = s6789;
      s3456 = s78910;

      src += 4 * src_stride;
      dst += 4 * dst_stride;
      h -= 4;
    } while (h != 0);
  } else {
    const uint8x16x2_t tran_concat_tbl = vld1q_u8_x2(dot_prod_tran_concat_tbl);
    uint8x16_t s0123_lo, s0123_hi, s1234_lo, s1234_hi, s2345_lo, s2345_hi,
        s3456_lo, s3456_hi, s4567_lo, s4567_hi, s5678_lo, s5678_hi, s6789_lo,
        s6789_hi, s78910_lo, s78910_hi;
    uint8x8_t d0, d1, d2, d3;
    const uint8_t *s;
    uint8_t *d;
    int height;

    do {
      height = h;
      s = src;
      d = dst;

      load_u8_8x7(s, src_stride, &s0, &s1, &s2, &s3, &s4, &s5, &s6);
      s += 7 * src_stride;

      s7 = vdup_n_u8(0);
      s8 = vdup_n_u8(0);
      s9 = vdup_n_u8(0);

      /* This operation combines a conventional transpose and the sample permute
       * (see horizontal case) required before computing the dot product.
       */
      transpose_concat_8x4(s0, s1, s2, s3, &s0123_lo, &s0123_hi,
                           tran_concat_tbl);
      transpose_concat_8x4(s1, s2, s3, s4, &s1234_lo, &s1234_hi,
                           tran_concat_tbl);
      transpose_concat_8x4(s2, s3, s4, s5, &s2345_lo, &s2345_hi,
                           tran_concat_tbl);
      transpose_concat_8x4(s3, s4, s5, s6, &s3456_lo, &s3456_hi,
                           tran_concat_tbl);
      transpose_concat_8x4(s4, s5, s6, s7, &s4567_lo, &s4567_hi,
                           tran_concat_tbl);
      transpose_concat_8x4(s5, s6, s7, s8, &s5678_lo, &s5678_hi,
                           tran_concat_tbl);
      transpose_concat_8x4(s6, s7, s8, s9, &s6789_lo, &s6789_hi,
                           tran_concat_tbl);

      do {
        load_u8_8x4(s, src_stride, &s7, &s8, &s9, &s10);

        transpose_concat_8x4(s7, s8, s9, s10, &s78910_lo, &s78910_hi,
                             tran_concat_tbl);

        /* Merge new data into block from previous iteration. */
        samples_LUT.val[0] = s3456_lo;
        samples_LUT.val[1] = s78910_lo;
        s4567_lo = vqtbl2q_u8(samples_LUT, merge_block_tbl.val[0]);
        s5678_lo = vqtbl2q_u8(samples_LUT, merge_block_tbl.val[1]);
        s6789_lo = vqtbl2q_u8(samples_LUT, merge_block_tbl.val[2]);

        samples_LUT.val[0] = s3456_hi;
        samples_LUT.val[1] = s78910_hi;
        s4567_hi = vqtbl2q_u8(samples_LUT, merge_block_tbl.val[0]);
        s5678_hi = vqtbl2q_u8(samples_LUT, merge_block_tbl.val[1]);
        s6789_hi = vqtbl2q_u8(samples_LUT, merge_block_tbl.val[2]);

        d0 = convolve8_8_usdot_partial(s0123_lo, s4567_lo, s0123_hi, s4567_hi,
                                       filters);
        d1 = convolve8_8_usdot_partial(s1234_lo, s5678_lo, s1234_hi, s5678_hi,
                                       filters);
        d2 = convolve8_8_usdot_partial(s2345_lo, s6789_lo, s2345_hi, s6789_hi,
                                       filters);
        d3 = convolve8_8_usdot_partial(s3456_lo, s78910_lo, s3456_hi, s78910_hi,
                                       filters);

        store_u8_8x4(d, dst_stride, d0, d1, d2, d3);

        /* Prepare block for next iteration - re-using as much as possible. */
        /* Shuffle everything up four rows. */
        s0123_lo = s4567_lo;
        s0123_hi = s4567_hi;
        s1234_lo = s5678_lo;
        s1234_hi = s5678_hi;
        s2345_lo = s6789_lo;
        s2345_hi = s6789_hi;
        s3456_lo = s78910_lo;
        s3456_hi = s78910_hi;

        s += 4 * src_stride;
        d += 4 * dst_stride;
        height -= 4;
      } while (height != 0);
      src += 8;
      dst += 8;
      w -= 8;
    } while (w != 0);
  }
}

void vpx_convolve8_avg_vert_neon_i8mm(const uint8_t *src, ptrdiff_t src_stride,
                                      uint8_t *dst, ptrdiff_t dst_stride,
                                      const InterpKernel *filter, int x0_q4,
                                      int x_step_q4, int y0_q4, int y_step_q4,
                                      int w, int h) {
  const int8x8_t filters = vmovn_s16(vld1q_s16(filter[y0_q4]));
  const uint8x16x3_t merge_block_tbl = vld1q_u8_x3(dot_prod_merge_block_tbl);
  uint8x8_t s0, s1, s2, s3, s4, s5, s6, s7, s8, s9, s10;
  uint8x16x2_t samples_LUT;

  assert((intptr_t)dst % 4 == 0);
  assert(dst_stride % 4 == 0);
  assert(y_step_q4 == 16);

  (void)x0_q4;
  (void)x_step_q4;
  (void)y_step_q4;

  src -= 3 * src_stride;

  if (w == 4) {
    const uint8x16_t tran_concat_tbl = vld1q_u8(dot_prod_tran_concat_tbl);
    uint8x16_t s0123, s1234, s2345, s3456, s4567, s5678, s6789, s78910;
    int16x4_t d0, d1, d2, d3;
    uint8x8_t d01, d23, dd01, dd23;

    load_u8_8x7(src, src_stride, &s0, &s1, &s2, &s3, &s4, &s5, &s6);
    src += 7 * src_stride;

    s7 = vdup_n_u8(0);
    s8 = vdup_n_u8(0);
    s9 = vdup_n_u8(0);

    /* This operation combines a conventional transpose and the sample permute
     * (see horizontal case) required before computing the dot product.
     */
    transpose_concat_4x4(s0, s1, s2, s3, &s0123, tran_concat_tbl);
    transpose_concat_4x4(s1, s2, s3, s4, &s1234, tran_concat_tbl);
    transpose_concat_4x4(s2, s3, s4, s5, &s2345, tran_concat_tbl);
    transpose_concat_4x4(s3, s4, s5, s6, &s3456, tran_concat_tbl);
    transpose_concat_4x4(s4, s5, s6, s7, &s4567, tran_concat_tbl);
    transpose_concat_4x4(s5, s6, s7, s8, &s5678, tran_concat_tbl);
    transpose_concat_4x4(s6, s7, s8, s9, &s6789, tran_concat_tbl);

    do {
      load_u8_8x4(src, src_stride, &s7, &s8, &s9, &s10);

      transpose_concat_4x4(s7, s8, s9, s10, &s78910, tran_concat_tbl);

      /* Merge new data into block from previous iteration. */
      samples_LUT.val[0] = s3456;
      samples_LUT.val[1] = s78910;
      s4567 = vqtbl2q_u8(samples_LUT, merge_block_tbl.val[0]);
      s5678 = vqtbl2q_u8(samples_LUT, merge_block_tbl.val[1]);
      s6789 = vqtbl2q_u8(samples_LUT, merge_block_tbl.val[2]);

      d0 = convolve8_4_usdot_partial(s0123, s4567, filters);
      d1 = convolve8_4_usdot_partial(s1234, s5678, filters);
      d2 = convolve8_4_usdot_partial(s2345, s6789, filters);
      d3 = convolve8_4_usdot_partial(s3456, s78910, filters);
      d01 = vqrshrun_n_s16(vcombine_s16(d0, d1), FILTER_BITS);
      d23 = vqrshrun_n_s16(vcombine_s16(d2, d3), FILTER_BITS);

      dd01 = load_u8(dst + 0 * dst_stride, dst_stride);
      dd23 = load_u8(dst + 2 * dst_stride, dst_stride);

      d01 = vrhadd_u8(d01, dd01);
      d23 = vrhadd_u8(d23, dd23);

      store_u8(dst + 0 * dst_stride, dst_stride, d01);
      store_u8(dst + 2 * dst_stride, dst_stride, d23);

      /* Prepare block for next iteration - re-using as much as possible. */
      /* Shuffle everything up four rows. */
      s0123 = s4567;
      s1234 = s5678;
      s2345 = s6789;
      s3456 = s78910;

      src += 4 * src_stride;
      dst += 4 * dst_stride;
      h -= 4;
    } while (h != 0);
  } else {
    const uint8x16x2_t tran_concat_tbl = vld1q_u8_x2(dot_prod_tran_concat_tbl);
    uint8x16_t s0123_lo, s0123_hi, s1234_lo, s1234_hi, s2345_lo, s2345_hi,
        s3456_lo, s3456_hi, s4567_lo, s4567_hi, s5678_lo, s5678_hi, s6789_lo,
        s6789_hi, s78910_lo, s78910_hi;
    uint8x8_t d0, d1, d2, d3, dd0, dd1, dd2, dd3;
    const uint8_t *s;
    uint8_t *d;
    int height;

    do {
      height = h;
      s = src;
      d = dst;

      load_u8_8x7(s, src_stride, &s0, &s1, &s2, &s3, &s4, &s5, &s6);
      s += 7 * src_stride;

      s7 = vdup_n_u8(0);
      s8 = vdup_n_u8(0);
      s9 = vdup_n_u8(0);

      /* This operation combines a conventional transpose and the sample permute
       * (see horizontal case) required before computing the dot product.
       */
      transpose_concat_8x4(s0, s1, s2, s3, &s0123_lo, &s0123_hi,
                           tran_concat_tbl);
      transpose_concat_8x4(s1, s2, s3, s4, &s1234_lo, &s1234_hi,
                           tran_concat_tbl);
      transpose_concat_8x4(s2, s3, s4, s5, &s2345_lo, &s2345_hi,
                           tran_concat_tbl);
      transpose_concat_8x4(s3, s4, s5, s6, &s3456_lo, &s3456_hi,
                           tran_concat_tbl);
      transpose_concat_8x4(s4, s5, s6, s7, &s4567_lo, &s4567_hi,
                           tran_concat_tbl);
      transpose_concat_8x4(s5, s6, s7, s8, &s5678_lo, &s5678_hi,
                           tran_concat_tbl);
      transpose_concat_8x4(s6, s7, s8, s9, &s6789_lo, &s6789_hi,
                           tran_concat_tbl);

      do {
        load_u8_8x4(s, src_stride, &s7, &s8, &s9, &s10);

        transpose_concat_8x4(s7, s8, s9, s10, &s78910_lo, &s78910_hi,
                             tran_concat_tbl);

        /* Merge new data into block from previous iteration. */
        samples_LUT.val[0] = s3456_lo;
        samples_LUT.val[1] = s78910_lo;
        s4567_lo = vqtbl2q_u8(samples_LUT, merge_block_tbl.val[0]);
        s5678_lo = vqtbl2q_u8(samples_LUT, merge_block_tbl.val[1]);
        s6789_lo = vqtbl2q_u8(samples_LUT, merge_block_tbl.val[2]);

        samples_LUT.val[0] = s3456_hi;
        samples_LUT.val[1] = s78910_hi;
        s4567_hi = vqtbl2q_u8(samples_LUT, merge_block_tbl.val[0]);
        s5678_hi = vqtbl2q_u8(samples_LUT, merge_block_tbl.val[1]);
        s6789_hi = vqtbl2q_u8(samples_LUT, merge_block_tbl.val[2]);

        d0 = convolve8_8_usdot_partial(s0123_lo, s4567_lo, s0123_hi, s4567_hi,
                                       filters);
        d1 = convolve8_8_usdot_partial(s1234_lo, s5678_lo, s1234_hi, s5678_hi,
                                       filters);
        d2 = convolve8_8_usdot_partial(s2345_lo, s6789_lo, s2345_hi, s6789_hi,
                                       filters);
        d3 = convolve8_8_usdot_partial(s3456_lo, s78910_lo, s3456_hi, s78910_hi,
                                       filters);

        load_u8_8x4(d, dst_stride, &dd0, &dd1, &dd2, &dd3);

        d0 = vrhadd_u8(d0, dd0);
        d1 = vrhadd_u8(d1, dd1);
        d2 = vrhadd_u8(d2, dd2);
        d3 = vrhadd_u8(d3, dd3);

        store_u8_8x4(d, dst_stride, d0, d1, d2, d3);

        /* Prepare block for next iteration - re-using as much as possible. */
        /* Shuffle everything up four rows. */
        s0123_lo = s4567_lo;
        s0123_hi = s4567_hi;
        s1234_lo = s5678_lo;
        s1234_hi = s5678_hi;
        s2345_lo = s6789_lo;
        s2345_hi = s6789_hi;
        s3456_lo = s78910_lo;
        s3456_hi = s78910_hi;

        s += 4 * src_stride;
        d += 4 * dst_stride;
        height -= 4;
      } while (height != 0);
      src += 8;
      dst += 8;
      w -= 8;
    } while (w != 0);
  }
}
