/*
 * Copyright (c) 2018, Alliance for Open Media. All rights reserved
 *
 * This source code is subject to the terms of the BSD 2 Clause License and
 * the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
 * was not distributed with this source code in the LICENSE file, you can
 * obtain it at www.aomedia.org/license/software. If the Alliance for Open
 * Media Patent License 1.0 was not distributed with this source code in the
 * PATENTS file, you can obtain it at www.aomedia.org/license/patent.
 */

#include <arm_neon.h>
#include <assert.h>

#include "config/aom_config.h"
#include "config/av1_rtcd.h"

#include "aom_dsp/txfm_common.h"
#include "aom_dsp/arm/mem_neon.h"
#include "aom_dsp/arm/transpose_neon.h"
#include "aom_ports/mem.h"
#include "av1/common/common.h"
#include "av1/common/arm/convolve_neon.h"

#if !defined(__aarch64__)
static INLINE void compute_avg_4x1(
    uint16x4_t res0, uint16x4_t d0, const uint16_t fwd_offset,
    const uint16_t bck_offset, const int16x4_t sub_const_vec,
    const int16_t round_bits, const int use_dist_wtd_comp_avg, uint8x8_t *t0) {
  int16x4_t tmp0;
  uint16x4_t tmp_u0;
  uint32x4_t sum0;
  int32x4_t dst0;
  int16x8_t tmp4;

  if (use_dist_wtd_comp_avg) {
    const int32x4_t round_bits_vec = vdupq_n_s32((int32_t)(-round_bits));

    sum0 = vmull_n_u16(res0, fwd_offset);
    sum0 = vmlal_n_u16(sum0, d0, bck_offset);

    sum0 = vshrq_n_u32(sum0, DIST_PRECISION_BITS);

    dst0 = vsubq_s32(vreinterpretq_s32_u32(sum0), vmovl_s16(sub_const_vec));

    dst0 = vqrshlq_s32(dst0, round_bits_vec);

    tmp0 = vmovn_s32(dst0);
    tmp4 = vcombine_s16(tmp0, tmp0);

    *t0 = vqmovun_s16(tmp4);
  } else {
    const int16x4_t round_bits_vec = vdup_n_s16(-round_bits);
    tmp_u0 = vhadd_u16(res0, d0);

    tmp0 = vsub_s16(vreinterpret_s16_u16(tmp_u0), sub_const_vec);

    tmp0 = vqrshl_s16(tmp0, round_bits_vec);

    tmp4 = vcombine_s16(tmp0, vdup_n_s16(0));

    *t0 = vqmovun_s16(tmp4);
  }
}

static INLINE void compute_avg_8x1(
    uint16x8_t res0, uint16x8_t d0, const uint16_t fwd_offset,
    const uint16_t bck_offset, const int16x4_t sub_const,
    const int16_t round_bits, const int use_dist_wtd_comp_avg, uint8x8_t *t0) {
  int16x8_t f0;
  uint32x4_t sum0, sum2;
  int32x4_t dst0, dst2;

  uint16x8_t tmp_u0;

  if (use_dist_wtd_comp_avg) {
    const int32x4_t sub_const_vec = vmovl_s16(sub_const);
    const int32x4_t round_bits_vec = vdupq_n_s32(-(int32_t)round_bits);

    sum0 = vmull_n_u16(vget_low_u16(res0), fwd_offset);
    sum0 = vmlal_n_u16(sum0, vget_low_u16(d0), bck_offset);
    sum0 = vshrq_n_u32(sum0, DIST_PRECISION_BITS);

    sum2 = vmull_n_u16(vget_high_u16(res0), fwd_offset);
    sum2 = vmlal_n_u16(sum2, vget_high_u16(d0), bck_offset);
    sum2 = vshrq_n_u32(sum2, DIST_PRECISION_BITS);

    dst0 = vsubq_s32(vreinterpretq_s32_u32(sum0), sub_const_vec);
    dst2 = vsubq_s32(vreinterpretq_s32_u32(sum2), sub_const_vec);

    dst0 = vqrshlq_s32(dst0, round_bits_vec);
    dst2 = vqrshlq_s32(dst2, round_bits_vec);

    f0 = vcombine_s16(vmovn_s32(dst0), vmovn_s32(dst2));

    *t0 = vqmovun_s16(f0);

  } else {
    const int16x8_t sub_const_vec = vcombine_s16(sub_const, sub_const);
    const int16x8_t round_bits_vec = vdupq_n_s16(-round_bits);

    tmp_u0 = vhaddq_u16(res0, d0);

    f0 = vsubq_s16(vreinterpretq_s16_u16(tmp_u0), sub_const_vec);

    f0 = vqrshlq_s16(f0, round_bits_vec);

    *t0 = vqmovun_s16(f0);
  }
}
#endif  // !defined(__arch64__)

static INLINE void compute_avg_4x4(
    uint16x4_t res0, uint16x4_t res1, uint16x4_t res2, uint16x4_t res3,
    uint16x4_t d0, uint16x4_t d1, uint16x4_t d2, uint16x4_t d3,
    const uint16_t fwd_offset, const uint16_t bck_offset,
    const int16x4_t sub_const_vec, const int16_t round_bits,
    const int use_dist_wtd_comp_avg, uint8x8_t *t0, uint8x8_t *t1) {
  int16x4_t tmp0, tmp1, tmp2, tmp3;
  uint16x4_t tmp_u0, tmp_u1, tmp_u2, tmp_u3;
  uint32x4_t sum0, sum1, sum2, sum3;

  int32x4_t dst0, dst1, dst2, dst3;
  int16x8_t tmp4, tmp5;

  if (use_dist_wtd_comp_avg) {
    const int32x4_t round_bits_vec = vdupq_n_s32((int32_t)(-round_bits));
    const int32x4_t const_vec = vmovl_s16(sub_const_vec);

    sum0 = vmull_n_u16(res0, fwd_offset);
    sum0 = vmlal_n_u16(sum0, d0, bck_offset);
    sum1 = vmull_n_u16(res1, fwd_offset);
    sum1 = vmlal_n_u16(sum1, d1, bck_offset);
    sum2 = vmull_n_u16(res2, fwd_offset);
    sum2 = vmlal_n_u16(sum2, d2, bck_offset);
    sum3 = vmull_n_u16(res3, fwd_offset);
    sum3 = vmlal_n_u16(sum3, d3, bck_offset);

    sum0 = vshrq_n_u32(sum0, DIST_PRECISION_BITS);
    sum1 = vshrq_n_u32(sum1, DIST_PRECISION_BITS);
    sum2 = vshrq_n_u32(sum2, DIST_PRECISION_BITS);
    sum3 = vshrq_n_u32(sum3, DIST_PRECISION_BITS);

    dst0 = vsubq_s32(vreinterpretq_s32_u32(sum0), const_vec);
    dst1 = vsubq_s32(vreinterpretq_s32_u32(sum1), const_vec);
    dst2 = vsubq_s32(vreinterpretq_s32_u32(sum2), const_vec);
    dst3 = vsubq_s32(vreinterpretq_s32_u32(sum3), const_vec);

    dst0 = vqrshlq_s32(dst0, round_bits_vec);
    dst1 = vqrshlq_s32(dst1, round_bits_vec);
    dst2 = vqrshlq_s32(dst2, round_bits_vec);
    dst3 = vqrshlq_s32(dst3, round_bits_vec);

    tmp4 = vcombine_s16(vmovn_s32(dst0), vmovn_s32(dst1));
    tmp5 = vcombine_s16(vmovn_s32(dst2), vmovn_s32(dst3));

    *t0 = vqmovun_s16(tmp4);
    *t1 = vqmovun_s16(tmp5);
  } else {
    const int16x4_t round_bits_vec = vdup_n_s16(-round_bits);
    tmp_u0 = vhadd_u16(res0, d0);
    tmp_u1 = vhadd_u16(res1, d1);
    tmp_u2 = vhadd_u16(res2, d2);
    tmp_u3 = vhadd_u16(res3, d3);

    tmp0 = vsub_s16(vreinterpret_s16_u16(tmp_u0), sub_const_vec);
    tmp1 = vsub_s16(vreinterpret_s16_u16(tmp_u1), sub_const_vec);
    tmp2 = vsub_s16(vreinterpret_s16_u16(tmp_u2), sub_const_vec);
    tmp3 = vsub_s16(vreinterpret_s16_u16(tmp_u3), sub_const_vec);

    tmp0 = vqrshl_s16(tmp0, round_bits_vec);
    tmp1 = vqrshl_s16(tmp1, round_bits_vec);
    tmp2 = vqrshl_s16(tmp2, round_bits_vec);
    tmp3 = vqrshl_s16(tmp3, round_bits_vec);

    tmp4 = vcombine_s16(tmp0, tmp1);
    tmp5 = vcombine_s16(tmp2, tmp3);

    *t0 = vqmovun_s16(tmp4);
    *t1 = vqmovun_s16(tmp5);
  }
}

static INLINE void compute_avg_8x4(
    uint16x8_t res0, uint16x8_t res1, uint16x8_t res2, uint16x8_t res3,
    uint16x8_t d0, uint16x8_t d1, uint16x8_t d2, uint16x8_t d3,
    const uint16_t fwd_offset, const uint16_t bck_offset,
    const int16x4_t sub_const, const int16_t round_bits,
    const int use_dist_wtd_comp_avg, uint8x8_t *t0, uint8x8_t *t1,
    uint8x8_t *t2, uint8x8_t *t3) {
  int16x8_t f0, f1, f2, f3;
  uint32x4_t sum0, sum1, sum2, sum3;
  uint32x4_t sum4, sum5, sum6, sum7;
  int32x4_t dst0, dst1, dst2, dst3;
  int32x4_t dst4, dst5, dst6, dst7;
  uint16x8_t tmp_u0, tmp_u1, tmp_u2, tmp_u3;

  if (use_dist_wtd_comp_avg) {
    const int32x4_t sub_const_vec = vmovl_s16(sub_const);
    const int32x4_t round_bits_vec = vdupq_n_s32(-(int32_t)round_bits);

    sum0 = vmull_n_u16(vget_low_u16(res0), fwd_offset);
    sum0 = vmlal_n_u16(sum0, vget_low_u16(d0), bck_offset);
    sum1 = vmull_n_u16(vget_low_u16(res1), fwd_offset);
    sum1 = vmlal_n_u16(sum1, vget_low_u16(d1), bck_offset);
    sum0 = vshrq_n_u32(sum0, DIST_PRECISION_BITS);
    sum1 = vshrq_n_u32(sum1, DIST_PRECISION_BITS);

    sum2 = vmull_n_u16(vget_high_u16(res0), fwd_offset);
    sum2 = vmlal_n_u16(sum2, vget_high_u16(d0), bck_offset);
    sum3 = vmull_n_u16(vget_high_u16(res1), fwd_offset);
    sum3 = vmlal_n_u16(sum3, vget_high_u16(d1), bck_offset);
    sum2 = vshrq_n_u32(sum2, DIST_PRECISION_BITS);
    sum3 = vshrq_n_u32(sum3, DIST_PRECISION_BITS);

    sum4 = vmull_n_u16(vget_low_u16(res2), fwd_offset);
    sum4 = vmlal_n_u16(sum4, vget_low_u16(d2), bck_offset);
    sum5 = vmull_n_u16(vget_low_u16(res3), fwd_offset);
    sum5 = vmlal_n_u16(sum5, vget_low_u16(d3), bck_offset);
    sum4 = vshrq_n_u32(sum4, DIST_PRECISION_BITS);
    sum5 = vshrq_n_u32(sum5, DIST_PRECISION_BITS);

    sum6 = vmull_n_u16(vget_high_u16(res2), fwd_offset);
    sum6 = vmlal_n_u16(sum6, vget_high_u16(d2), bck_offset);
    sum7 = vmull_n_u16(vget_high_u16(res3), fwd_offset);
    sum7 = vmlal_n_u16(sum7, vget_high_u16(d3), bck_offset);
    sum6 = vshrq_n_u32(sum6, DIST_PRECISION_BITS);
    sum7 = vshrq_n_u32(sum7, DIST_PRECISION_BITS);

    dst0 = vsubq_s32(vreinterpretq_s32_u32(sum0), sub_const_vec);
    dst1 = vsubq_s32(vreinterpretq_s32_u32(sum1), sub_const_vec);
    dst2 = vsubq_s32(vreinterpretq_s32_u32(sum2), sub_const_vec);
    dst3 = vsubq_s32(vreinterpretq_s32_u32(sum3), sub_const_vec);
    dst4 = vsubq_s32(vreinterpretq_s32_u32(sum4), sub_const_vec);
    dst5 = vsubq_s32(vreinterpretq_s32_u32(sum5), sub_const_vec);
    dst6 = vsubq_s32(vreinterpretq_s32_u32(sum6), sub_const_vec);
    dst7 = vsubq_s32(vreinterpretq_s32_u32(sum7), sub_const_vec);

    dst0 = vqrshlq_s32(dst0, round_bits_vec);
    dst1 = vqrshlq_s32(dst1, round_bits_vec);
    dst2 = vqrshlq_s32(dst2, round_bits_vec);
    dst3 = vqrshlq_s32(dst3, round_bits_vec);
    dst4 = vqrshlq_s32(dst4, round_bits_vec);
    dst5 = vqrshlq_s32(dst5, round_bits_vec);
    dst6 = vqrshlq_s32(dst6, round_bits_vec);
    dst7 = vqrshlq_s32(dst7, round_bits_vec);

    f0 = vcombine_s16(vmovn_s32(dst0), vmovn_s32(dst2));
    f1 = vcombine_s16(vmovn_s32(dst1), vmovn_s32(dst3));
    f2 = vcombine_s16(vmovn_s32(dst4), vmovn_s32(dst6));
    f3 = vcombine_s16(vmovn_s32(dst5), vmovn_s32(dst7));

    *t0 = vqmovun_s16(f0);
    *t1 = vqmovun_s16(f1);
    *t2 = vqmovun_s16(f2);
    *t3 = vqmovun_s16(f3);

  } else {
    const int16x8_t sub_const_vec = vcombine_s16(sub_const, sub_const);
    const int16x8_t round_bits_vec = vdupq_n_s16(-round_bits);

    tmp_u0 = vhaddq_u16(res0, d0);
    tmp_u1 = vhaddq_u16(res1, d1);
    tmp_u2 = vhaddq_u16(res2, d2);
    tmp_u3 = vhaddq_u16(res3, d3);

    f0 = vsubq_s16(vreinterpretq_s16_u16(tmp_u0), sub_const_vec);
    f1 = vsubq_s16(vreinterpretq_s16_u16(tmp_u1), sub_const_vec);
    f2 = vsubq_s16(vreinterpretq_s16_u16(tmp_u2), sub_const_vec);
    f3 = vsubq_s16(vreinterpretq_s16_u16(tmp_u3), sub_const_vec);

    f0 = vqrshlq_s16(f0, round_bits_vec);
    f1 = vqrshlq_s16(f1, round_bits_vec);
    f2 = vqrshlq_s16(f2, round_bits_vec);
    f3 = vqrshlq_s16(f3, round_bits_vec);

    *t0 = vqmovun_s16(f0);
    *t1 = vqmovun_s16(f1);
    *t2 = vqmovun_s16(f2);
    *t3 = vqmovun_s16(f3);
  }
}

#if defined(__aarch64__) && defined(__ARM_FEATURE_DOTPROD)

static INLINE void dist_wtd_convolve_2d_horiz_neon(
    const uint8_t *src, int src_stride, int16_t *im_block, const int im_stride,
    const int16x8_t x_filter_s16, const int im_h, int w, const int round_0) {
  const int bd = 8;
  int16_t *dst_ptr = im_block;
  int dst_stride = im_stride;
  int width = w;
  int height = im_h;

  const int8x8_t x_filter = vmovn_s16(x_filter_s16);
  const int32_t horiz_const = (1 << (bd + FILTER_BITS - 2));
  // Dot product constants.
  const int16x8_t correct_tmp = vshlq_n_s16(x_filter_s16, 7);
  const int32x4_t correction =
      vdupq_n_s32(vaddlvq_s16(correct_tmp) + horiz_const);
  const uint8x16_t range_limit = vdupq_n_u8(128);

  if (w == 4) {
    const uint8x16x2_t permute_tbl = vld1q_u8_x2(dot_prod_permute_tbl);
    const int16x4_t shift_round_0 = vdup_n_s16(-(round_0));
    uint8x16_t s0, s1, s2, s3;
    int32x4_t t0, t1, t2, t3;
    int16x4_t d0, d1, d2, d3;

    do {
      s0 = vld1q_u8(src + 0 * src_stride);
      s1 = vld1q_u8(src + 1 * src_stride);
      s2 = vld1q_u8(src + 2 * src_stride);
      s3 = vld1q_u8(src + 3 * src_stride);

      t0 = convolve8_4_dot_s16(s0, x_filter, correction, range_limit,
                               permute_tbl);
      t1 = convolve8_4_dot_s16(s1, x_filter, correction, range_limit,
                               permute_tbl);
      t2 = convolve8_4_dot_s16(s2, x_filter, correction, range_limit,
                               permute_tbl);
      t3 = convolve8_4_dot_s16(s3, x_filter, correction, range_limit,
                               permute_tbl);

      d0 = vqrshl_s16(vmovn_s32(t0), shift_round_0);
      d1 = vqrshl_s16(vmovn_s32(t1), shift_round_0);
      d2 = vqrshl_s16(vmovn_s32(t2), shift_round_0);
      d3 = vqrshl_s16(vmovn_s32(t3), shift_round_0);

      vst1_s16((dst_ptr + 0 * dst_stride), d0);
      vst1_s16((dst_ptr + 1 * dst_stride), d1);
      vst1_s16((dst_ptr + 2 * dst_stride), d2);
      vst1_s16((dst_ptr + 3 * dst_stride), d3);

      src += 4 * src_stride;
      dst_ptr += 4 * dst_stride;
      height -= 4;
    } while (height > 0);
  } else {
    const uint8x16x3_t permute_tbl = vld1q_u8_x3(dot_prod_permute_tbl);
    const int16x8_t shift_round_0 = vdupq_n_s16(-(round_0));
    const uint8_t *s;
    int16_t *d;
    uint8x16_t s0, s1, s2, s3;
    int16x8_t d0, d1, d2, d3;

    do {
      width = w;
      s = src;
      d = dst_ptr;

      do {
        s0 = vld1q_u8(s + 0 * src_stride);
        s1 = vld1q_u8(s + 1 * src_stride);
        s2 = vld1q_u8(s + 2 * src_stride);
        s3 = vld1q_u8(s + 3 * src_stride);

        d0 = convolve8_8_dot_s16(s0, x_filter, correction, range_limit,
                                 permute_tbl, shift_round_0);
        d1 = convolve8_8_dot_s16(s1, x_filter, correction, range_limit,
                                 permute_tbl, shift_round_0);
        d2 = convolve8_8_dot_s16(s2, x_filter, correction, range_limit,
                                 permute_tbl, shift_round_0);
        d3 = convolve8_8_dot_s16(s3, x_filter, correction, range_limit,
                                 permute_tbl, shift_round_0);

        vst1q_s16(d + 0 * dst_stride, d0);
        vst1q_s16(d + 1 * dst_stride, d1);
        vst1q_s16(d + 2 * dst_stride, d2);
        vst1q_s16(d + 3 * dst_stride, d3);

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

      src += 4 * src_stride;
      dst_ptr += 4 * dst_stride;
      height -= 4;
    } while (height > 0);
  }
}

#else  // !(defined(__aarch64__) && defined(__ARM_FEATURE_DOTPROD))

static INLINE void dist_wtd_convolve_2d_horiz_neon(
    const uint8_t *src, int src_stride, int16_t *im_block, const int im_stride,
    const int16x8_t x_filter, const int im_h, int w, const int round_0) {
  const int bd = 8;
  const uint8_t *s;
  int16_t *dst_ptr;
  int dst_stride;
  int width, height;

  dst_ptr = im_block;
  dst_stride = im_stride;
  height = im_h;
  width = w;

  if (w == 4) {
    int16x4_t s0, s1, s2, s3, s4, s5, s6, s7, d0;
    int16x8_t tt0;
    uint8x8_t t0;

    const int16x4_t horiz_const = vdup_n_s16((1 << (bd + FILTER_BITS - 2)));
    const int16x4_t shift_round_0 = vdup_n_s16(-(round_0));

#if defined(__aarch64__)
    int16x4_t s8, s9, s10, d1, d2, d3;
    int16x8_t tt1, tt2, tt3;
    uint8x8_t t1, t2, t3;
#endif
    do {
      s = src;
      __builtin_prefetch(s + 0 * src_stride);
#if defined(__aarch64__)
      __builtin_prefetch(s + 1 * src_stride);
      __builtin_prefetch(s + 2 * src_stride);
      __builtin_prefetch(s + 3 * src_stride);

      load_u8_8x4(s, src_stride, &t0, &t1, &t2, &t3);
      transpose_u8_8x4(&t0, &t1, &t2, &t3);
      tt0 = vreinterpretq_s16_u16(vmovl_u8(t0));
      tt1 = vreinterpretq_s16_u16(vmovl_u8(t1));
      tt2 = vreinterpretq_s16_u16(vmovl_u8(t2));
      tt3 = vreinterpretq_s16_u16(vmovl_u8(t3));
      s0 = vget_low_s16(tt0);
      s1 = vget_low_s16(tt1);
      s2 = vget_low_s16(tt2);
      s3 = vget_low_s16(tt3);
      s4 = vget_high_s16(tt0);
      s5 = vget_high_s16(tt1);
      s6 = vget_high_s16(tt2);
      __builtin_prefetch(dst_ptr + 0 * dst_stride);
      __builtin_prefetch(dst_ptr + 1 * dst_stride);
      __builtin_prefetch(dst_ptr + 2 * dst_stride);
      __builtin_prefetch(dst_ptr + 3 * dst_stride);
      s += 7;

      load_u8_8x4(s, src_stride, &t0, &t1, &t2, &t3);
      transpose_u8_8x4(&t0, &t1, &t2, &t3);
      tt0 = vreinterpretq_s16_u16(vmovl_u8(t0));
      tt1 = vreinterpretq_s16_u16(vmovl_u8(t1));
      tt2 = vreinterpretq_s16_u16(vmovl_u8(t2));
      tt3 = vreinterpretq_s16_u16(vmovl_u8(t3));
      s7 = vget_low_s16(tt0);
      s8 = vget_low_s16(tt1);
      s9 = vget_low_s16(tt2);
      s10 = vget_low_s16(tt3);

      d0 = convolve8_4x4_s16(s0, s1, s2, s3, s4, s5, s6, s7, x_filter,
                             horiz_const, shift_round_0);
      d1 = convolve8_4x4_s16(s1, s2, s3, s4, s5, s6, s7, s8, x_filter,
                             horiz_const, shift_round_0);
      d2 = convolve8_4x4_s16(s2, s3, s4, s5, s6, s7, s8, s9, x_filter,
                             horiz_const, shift_round_0);
      d3 = convolve8_4x4_s16(s3, s4, s5, s6, s7, s8, s9, s10, x_filter,
                             horiz_const, shift_round_0);

      transpose_s16_4x4d(&d0, &d1, &d2, &d3);

      vst1_s16((dst_ptr + 0 * dst_stride), d0);
      vst1_s16((dst_ptr + 1 * dst_stride), d1);
      vst1_s16((dst_ptr + 2 * dst_stride), d2);
      vst1_s16((dst_ptr + 3 * dst_stride), d3);

      src += 4 * src_stride;
      dst_ptr += 4 * dst_stride;
      height -= 4;
#else
      t0 = vld1_u8(s);                            // a0 a1 a2 a3 a4 a5 a6 a7
      tt0 = vreinterpretq_s16_u16(vmovl_u8(t0));  // a0 a1 a2 a3 a4 a5 a6 a7
      s0 = vget_low_s16(tt0);                     // a0 a1 a2 a3
      s4 = vget_high_s16(tt0);                    // a4 a5 a6 a7
      __builtin_prefetch(dst_ptr);
      s += 8;
      t0 = vld1_u8(s);  // a8 a9 a10 a11

      // a8 a9 a10 a11
      s7 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t0)));

      s1 = vext_s16(s0, s4, 1);  // a1 a2 a3 a4
      s2 = vext_s16(s0, s4, 2);  // a2 a3 a4 a5
      s3 = vext_s16(s0, s4, 3);  // a3 a4 a5 a6
      s5 = vext_s16(s4, s7, 1);  // a5 a6 a7 a8
      s6 = vext_s16(s4, s7, 2);  // a6 a7 a8 a9
      s7 = vext_s16(s4, s7, 3);  // a7 a8 a9 a10

      d0 = convolve8_4x4_s16(s0, s1, s2, s3, s4, s5, s6, s7, x_filter,
                             horiz_const, shift_round_0);

      vst1_s16(dst_ptr, d0);

      src += src_stride;
      dst_ptr += dst_stride;
      height -= 1;
#endif
    } while (height > 0);
  } else {
    int16_t *d_tmp;
    int16x8_t s0, s1, s2, s3, s4, s5, s6, s7;
    int16x8_t res0;
    uint8x8_t t0;

    const int16x8_t horiz_const = vdupq_n_s16((1 << (bd + FILTER_BITS - 2)));
    const int16x8_t shift_round_0 = vdupq_n_s16(-(round_0));
    do {
#if defined(__aarch64__)
      uint8x8_t t1, t2, t3, t4, t5, t6, t7;
      int16x8_t s8, s9, s10, s11, s12, s13, s14;
      int16x8_t res1, res2, res3, res4, res5, res6, res7;
      __builtin_prefetch(src + 0 * src_stride);
      __builtin_prefetch(src + 1 * src_stride);
      __builtin_prefetch(src + 2 * src_stride);
      __builtin_prefetch(src + 3 * src_stride);
      __builtin_prefetch(src + 4 * src_stride);
      __builtin_prefetch(src + 5 * src_stride);
      __builtin_prefetch(src + 6 * src_stride);
      __builtin_prefetch(src + 7 * src_stride);
      load_u8_8x8(src, src_stride, &t0, &t1, &t2, &t3, &t4, &t5, &t6, &t7);
      transpose_u8_8x8(&t0, &t1, &t2, &t3, &t4, &t5, &t6, &t7);
      s0 = vreinterpretq_s16_u16(vmovl_u8(t0));
      s1 = vreinterpretq_s16_u16(vmovl_u8(t1));
      s2 = vreinterpretq_s16_u16(vmovl_u8(t2));
      s3 = vreinterpretq_s16_u16(vmovl_u8(t3));
      s4 = vreinterpretq_s16_u16(vmovl_u8(t4));
      s5 = vreinterpretq_s16_u16(vmovl_u8(t5));
      s6 = vreinterpretq_s16_u16(vmovl_u8(t6));

      width = w;
      s = src + 7;
      d_tmp = dst_ptr;
      __builtin_prefetch(dst_ptr + 0 * dst_stride);
      __builtin_prefetch(dst_ptr + 1 * dst_stride);
      __builtin_prefetch(dst_ptr + 2 * dst_stride);
      __builtin_prefetch(dst_ptr + 3 * dst_stride);
      __builtin_prefetch(dst_ptr + 4 * dst_stride);
      __builtin_prefetch(dst_ptr + 5 * dst_stride);
      __builtin_prefetch(dst_ptr + 6 * dst_stride);
      __builtin_prefetch(dst_ptr + 7 * dst_stride);

      do {
        load_u8_8x8(s, src_stride, &t0, &t1, &t2, &t3, &t4, &t5, &t6, &t7);
        transpose_u8_8x8(&t0, &t1, &t2, &t3, &t4, &t5, &t6, &t7);
        s7 = vreinterpretq_s16_u16(vmovl_u8(t0));
        s8 = vreinterpretq_s16_u16(vmovl_u8(t1));
        s9 = vreinterpretq_s16_u16(vmovl_u8(t2));
        s10 = vreinterpretq_s16_u16(vmovl_u8(t3));
        s11 = vreinterpretq_s16_u16(vmovl_u8(t4));
        s12 = vreinterpretq_s16_u16(vmovl_u8(t5));
        s13 = vreinterpretq_s16_u16(vmovl_u8(t6));
        s14 = vreinterpretq_s16_u16(vmovl_u8(t7));

        res0 = convolve8_8x8_s16(s0, s1, s2, s3, s4, s5, s6, s7, x_filter,
                                 horiz_const, shift_round_0);
        res1 = convolve8_8x8_s16(s1, s2, s3, s4, s5, s6, s7, s8, x_filter,
                                 horiz_const, shift_round_0);
        res2 = convolve8_8x8_s16(s2, s3, s4, s5, s6, s7, s8, s9, x_filter,
                                 horiz_const, shift_round_0);
        res3 = convolve8_8x8_s16(s3, s4, s5, s6, s7, s8, s9, s10, x_filter,
                                 horiz_const, shift_round_0);
        res4 = convolve8_8x8_s16(s4, s5, s6, s7, s8, s9, s10, s11, x_filter,
                                 horiz_const, shift_round_0);
        res5 = convolve8_8x8_s16(s5, s6, s7, s8, s9, s10, s11, s12, x_filter,
                                 horiz_const, shift_round_0);
        res6 = convolve8_8x8_s16(s6, s7, s8, s9, s10, s11, s12, s13, x_filter,
                                 horiz_const, shift_round_0);
        res7 = convolve8_8x8_s16(s7, s8, s9, s10, s11, s12, s13, s14, x_filter,
                                 horiz_const, shift_round_0);

        transpose_s16_8x8(&res0, &res1, &res2, &res3, &res4, &res5, &res6,
                          &res7);

        store_s16_8x8(d_tmp, dst_stride, res0, res1, res2, res3, res4, res5,
                      res6, res7);
        s0 = s8;
        s1 = s9;
        s2 = s10;
        s3 = s11;
        s4 = s12;
        s5 = s13;
        s6 = s14;
        s += 8;
        d_tmp += 8;
        width -= 8;
      } while (width > 0);
      src += 8 * src_stride;
      dst_ptr += 8 * dst_stride;
      height -= 8;
#else
      int16x8_t temp_0;
      t0 = vld1_u8(src);
      s0 = vreinterpretq_s16_u16(vmovl_u8(t0));  // a0 a1 a2 a3 a4 a5 a6 a7

      width = w;
      s = src + 8;
      d_tmp = dst_ptr;
      __builtin_prefetch(dst_ptr);

      do {
        t0 = vld1_u8(s);  // a8 a9 a10 a11 a12 a13 a14 a15
        s7 = vreinterpretq_s16_u16(vmovl_u8(t0));
        temp_0 = s0;
        s0 = s7;

        s1 = vextq_s16(temp_0, s7, 1);  // a1 a2 a3 a4 a5 a6 a7 a8
        s2 = vextq_s16(temp_0, s7, 2);  // a2 a3 a4 a5 a6 a7 a8 a9
        s3 = vextq_s16(temp_0, s7, 3);  // a3 a4 a5 a6 a7 a8 a9 a10
        s4 = vextq_s16(temp_0, s7, 4);  // a4 a5 a6 a7 a8 a9 a10 a11
        s5 = vextq_s16(temp_0, s7, 5);  // a5 a6 a7 a8 a9 a10 a11 a12
        s6 = vextq_s16(temp_0, s7, 6);  // a6 a7 a8 a9 a10 a11 a12 a13
        s7 = vextq_s16(temp_0, s7, 7);  // a7 a8 a9 a10 a11 a12 a13 a14

        res0 = convolve8_8x8_s16(temp_0, s1, s2, s3, s4, s5, s6, s7, x_filter,
                                 horiz_const, shift_round_0);
        vst1q_s16(d_tmp, res0);

        s += 8;
        d_tmp += 8;
        width -= 8;
      } while (width > 0);
      src += src_stride;
      dst_ptr += dst_stride;
      height -= 1;
#endif
    } while (height > 0);
  }
}

#endif  // defined(__aarch64__) && defined(__ARM_FEATURE_DOTPROD)

static INLINE void dist_wtd_convolve_2d_vert_neon(
    int16_t *im_block, const int im_stride, uint8_t *dst8, int dst8_stride,
    ConvolveParams *conv_params, const int16x8_t y_filter, int h, int w) {
  uint8_t *dst_u8_ptr, *d_u8;
  CONV_BUF_TYPE *dst_ptr, *dst;
  int16_t *src_ptr, *s;
  uint16_t *d;

  const int bd = 8;
  int height;
  int dst_stride = conv_params->dst_stride;
  const int offset_bits = bd + 2 * FILTER_BITS - conv_params->round_0;
  const int16_t sub_const = (1 << (offset_bits - conv_params->round_1)) +
                            (1 << (offset_bits - conv_params->round_1 - 1));

  const int16_t round_bits =
      2 * FILTER_BITS - conv_params->round_0 - conv_params->round_1;
  const int offset = bd + 2 * FILTER_BITS - conv_params->round_0;
  const int32x4_t round_shift_vec = vdupq_n_s32(-(conv_params->round_1));
  const int32x4_t offset_const = vdupq_n_s32(1 << offset);
  const int16x4_t sub_const_vec = vdup_n_s16(sub_const);
  const uint16_t fwd_offset = conv_params->fwd_offset;
  const uint16_t bck_offset = conv_params->bck_offset;
  const int do_average = conv_params->do_average;
  const int use_dist_wtd_comp_avg = conv_params->use_dist_wtd_comp_avg;

  int16x4_t s0, s1, s2, s3, s4, s5, s6, s7;
  uint16x4_t res4, d0;
  uint8x8_t t0;

#if defined(__aarch64__)
  int16x4_t s8, s9, s10;
  uint16x4_t res5, res6, res7, d1, d2, d3;
  uint8x8_t t1;
#endif

  dst = conv_params->dst;
  src_ptr = im_block;
  dst_u8_ptr = dst8;
  dst_ptr = dst;
  height = h;

  do {
    d = dst_ptr;
    d_u8 = dst_u8_ptr;
    s = src_ptr;
    height = h;

    __builtin_prefetch(s + 0 * im_stride);
    __builtin_prefetch(s + 1 * im_stride);
    __builtin_prefetch(s + 2 * im_stride);
    __builtin_prefetch(s + 3 * im_stride);
    __builtin_prefetch(s + 4 * im_stride);
    __builtin_prefetch(s + 5 * im_stride);
    __builtin_prefetch(s + 6 * im_stride);
    __builtin_prefetch(s + 7 * im_stride);

    load_s16_4x8(s, im_stride, &s0, &s1, &s2, &s3, &s4, &s5, &s6, &s7);
    s += (7 * im_stride);

    do {
#if defined(__aarch64__)
      load_s16_4x4(s, im_stride, &s7, &s8, &s9, &s10);
      s += (im_stride << 2);

      __builtin_prefetch(d + 0 * dst_stride);
      __builtin_prefetch(d + 1 * dst_stride);
      __builtin_prefetch(d + 2 * dst_stride);
      __builtin_prefetch(d + 3 * dst_stride);

      __builtin_prefetch(d_u8 + 4 * dst8_stride);
      __builtin_prefetch(d_u8 + 5 * dst8_stride);
      __builtin_prefetch(d_u8 + 6 * dst8_stride);
      __builtin_prefetch(d_u8 + 7 * dst8_stride);

      d0 = convolve8_4x4_s32(s0, s1, s2, s3, s4, s5, s6, s7, y_filter,
                             round_shift_vec, offset_const);
      d1 = convolve8_4x4_s32(s1, s2, s3, s4, s5, s6, s7, s8, y_filter,
                             round_shift_vec, offset_const);
      d2 = convolve8_4x4_s32(s2, s3, s4, s5, s6, s7, s8, s9, y_filter,
                             round_shift_vec, offset_const);
      d3 = convolve8_4x4_s32(s3, s4, s5, s6, s7, s8, s9, s10, y_filter,
                             round_shift_vec, offset_const);

      if (do_average) {
        load_u16_4x4(d, dst_stride, &res4, &res5, &res6, &res7);
        d += (dst_stride << 2);

        compute_avg_4x4(res4, res5, res6, res7, d0, d1, d2, d3, fwd_offset,
                        bck_offset, sub_const_vec, round_bits,
                        use_dist_wtd_comp_avg, &t0, &t1);

        vst1_lane_u32((uint32_t *)d_u8, vreinterpret_u32_u8(t0), 0);
        d_u8 += dst8_stride;
        vst1_lane_u32((uint32_t *)d_u8, vreinterpret_u32_u8(t0), 1);
        d_u8 += dst8_stride;
        vst1_lane_u32((uint32_t *)d_u8, vreinterpret_u32_u8(t1), 0);
        d_u8 += dst8_stride;
        vst1_lane_u32((uint32_t *)d_u8, vreinterpret_u32_u8(t1), 1);
        d_u8 += dst8_stride;

      } else {
        store_u16_4x4(d, dst_stride, d0, d1, d2, d3);
        d += (dst_stride << 2);
      }
      s0 = s4;
      s1 = s5;
      s2 = s6;
      s3 = s7;
      s4 = s8;
      s5 = s9;
      s6 = s10;
      height -= 4;
#else
      s7 = vld1_s16(s);
      s += (im_stride);

      __builtin_prefetch(d + 0 * dst_stride);
      __builtin_prefetch(d_u8 + 0 * dst8_stride);

      d0 = convolve8_4x4_s32(s0, s1, s2, s3, s4, s5, s6, s7, y_filter,
                             round_shift_vec, offset_const);

      if (do_average) {
        res4 = vld1_u16(d);
        d += (dst_stride);

        compute_avg_4x1(res4, d0, fwd_offset, bck_offset, sub_const_vec,
                        round_bits, use_dist_wtd_comp_avg, &t0);

        vst1_lane_u32((uint32_t *)d_u8, vreinterpret_u32_u8(t0), 0);
        d_u8 += dst8_stride;

      } else {
        vst1_u16(d, d0);
        d += (dst_stride);
      }
      s0 = s1;
      s1 = s2;
      s2 = s3;
      s3 = s4;
      s4 = s5;
      s5 = s6;
      s6 = s7;
      height--;
#endif
    } while (height > 0);
    src_ptr += 4;
    dst_ptr += 4;
    dst_u8_ptr += 4;
    w -= 4;
  } while (w > 0);
}

void av1_dist_wtd_convolve_2d_neon(const uint8_t *src, int src_stride,
                                   uint8_t *dst8, int dst8_stride, int w, int h,
                                   const InterpFilterParams *filter_params_x,
                                   const InterpFilterParams *filter_params_y,
                                   const int subpel_x_qn, const int subpel_y_qn,
                                   ConvolveParams *conv_params) {
  assert(!(w % 4));
  assert(!(h % 4));

  DECLARE_ALIGNED(16, int16_t,
                  im_block[(MAX_SB_SIZE + HORIZ_EXTRA_ROWS) * MAX_SB_SIZE]);

  const int im_h = h + filter_params_y->taps - 1;
  const int im_stride = MAX_SB_SIZE;
  const int vert_offset = filter_params_y->taps / 2 - 1;
  const int horiz_offset = filter_params_x->taps / 2 - 1;
  const int round_0 = conv_params->round_0 - 1;
  const uint8_t *src_ptr = src - vert_offset * src_stride - horiz_offset;
  const int16_t *x_filter_ptr = av1_get_interp_filter_subpel_kernel(
      filter_params_x, subpel_x_qn & SUBPEL_MASK);
  const int16_t *y_filter_ptr = av1_get_interp_filter_subpel_kernel(
      filter_params_y, subpel_y_qn & SUBPEL_MASK);

  // Filter values are even, so downshift by 1 to reduce intermediate precision
  // requirements.
  const int16x8_t x_filter = vshrq_n_s16(vld1q_s16(x_filter_ptr), 1);
  const int16x8_t y_filter = vld1q_s16(y_filter_ptr);

  dist_wtd_convolve_2d_horiz_neon(src_ptr, src_stride, im_block, im_stride,
                                  x_filter, im_h, w, round_0);

  dist_wtd_convolve_2d_vert_neon(im_block, im_stride, dst8, dst8_stride,
                                 conv_params, y_filter, h, w);
}

void av1_dist_wtd_convolve_2d_copy_neon(const uint8_t *src, int src_stride,
                                        uint8_t *dst8, int dst8_stride, int w,
                                        int h, ConvolveParams *conv_params) {
  uint8x8_t res0_8, res1_8, res2_8, res3_8, tmp_shift0, tmp_shift1, tmp_shift2,
      tmp_shift3;
  uint16x8_t res_q0, res_q1, res_q2, res_q3, tmp_q0, tmp_q1, tmp_q2, tmp_q3;
  uint16x4_t tmp4, tmp5, tmp6, tmp7, res4, res5, res6, res7;
  const uint8_t *src1, *src2;
  uint8_t *dst8_1;
  CONV_BUF_TYPE *dst = conv_params->dst, *dst_1, *dst_2;
  const int dst_stride = conv_params->dst_stride;
  int x, y;
  const int16_t bits =
      FILTER_BITS * 2 - conv_params->round_1 - conv_params->round_0;
  const int bd = 8;
  const int offset_bits = bd + 2 * FILTER_BITS - conv_params->round_0;
  const int round_offset = (1 << (offset_bits - conv_params->round_1)) +
                           (1 << (offset_bits - conv_params->round_1 - 1));
  const int16x4_t sub_const_vec = vdup_n_s16((int16_t)round_offset);
  const uint16x8_t dup_round_offset16x8 = vdupq_n_u16((uint16_t)round_offset);
  const int16x4_t dup_bits16x4 = vdup_n_s16(bits);
  const int16x8_t dup_bits16x8 = vdupq_n_s16(bits);

  if (!(w & 0x07)) {
    for (y = 0; y < (h >> 2); ++y) {
      src1 = src;
      dst8_1 = dst8;
      dst_1 = dst;
      for (x = 0; x < (w >> 3); ++x) {
        src2 = src1;
        load_u8_8x4(src2, src_stride, &res0_8, &res1_8, &res2_8, &res3_8);

        res_q0 = vaddq_u16(vshlq_u16(vmovl_u8(res0_8), dup_bits16x8),
                           dup_round_offset16x8);
        res_q1 = vaddq_u16(vshlq_u16(vmovl_u8(res1_8), dup_bits16x8),
                           dup_round_offset16x8);
        res_q2 = vaddq_u16(vshlq_u16(vmovl_u8(res2_8), dup_bits16x8),
                           dup_round_offset16x8);
        res_q3 = vaddq_u16(vshlq_u16(vmovl_u8(res3_8), dup_bits16x8),
                           dup_round_offset16x8);

        if (conv_params->do_average) {
          dst_2 = dst_1;
          load_u16_8x4(dst_2, dst_stride, &tmp_q0, &tmp_q1, &tmp_q2, &tmp_q3);

          compute_avg_8x4(tmp_q0, tmp_q1, tmp_q2, tmp_q3, res_q0, res_q1,
                          res_q2, res_q3, conv_params->fwd_offset,
                          conv_params->bck_offset, sub_const_vec, bits,
                          conv_params->use_dist_wtd_comp_avg, &tmp_shift0,
                          &tmp_shift1, &tmp_shift2, &tmp_shift3);

          vst1_u8(dst8_1 + (0 * dst8_stride), tmp_shift0);
          vst1_u8(dst8_1 + (1 * dst8_stride), tmp_shift1);
          vst1_u8(dst8_1 + (2 * dst8_stride), tmp_shift2);
          vst1_u8(dst8_1 + (3 * dst8_stride), tmp_shift3);

        } else {
          vst1q_u16(dst_1 + (0 * dst_stride), res_q0);
          vst1q_u16(dst_1 + (1 * dst_stride), res_q1);
          vst1q_u16(dst_1 + (2 * dst_stride), res_q2);
          vst1q_u16(dst_1 + (3 * dst_stride), res_q3);
        }
        src1 = src1 + 8;
        dst_1 = dst_1 + 8;
        dst8_1 = dst8_1 + 8;
      }
      src += src_stride * 4;
      dst8 += dst8_stride * 4;
      dst += dst_stride * 4;
    }
  } else if (!(w & 0x03)) {
    for (y = 0; y < (h >> 2); ++y) {
      src1 = src;
      dst8_1 = dst8;
      dst_1 = dst;

      load_u8_8x4(src1, src_stride, &res0_8, &res1_8, &res2_8, &res3_8);

      res4 = vadd_u16(vshl_u16(vget_low_u16(vmovl_u8(res0_8)), dup_bits16x4),
                      vreinterpret_u16_s16(sub_const_vec));
      res5 = vadd_u16(vshl_u16(vget_low_u16(vmovl_u8(res1_8)), dup_bits16x4),
                      vreinterpret_u16_s16(sub_const_vec));
      res6 = vadd_u16(vshl_u16(vget_low_u16(vmovl_u8(res2_8)), dup_bits16x4),
                      vreinterpret_u16_s16(sub_const_vec));
      res7 = vadd_u16(vshl_u16(vget_low_u16(vmovl_u8(res3_8)), dup_bits16x4),
                      vreinterpret_u16_s16(sub_const_vec));
      if (conv_params->do_average) {
        load_u16_4x4(dst_1, dst_stride, &tmp4, &tmp5, &tmp6, &tmp7);

        compute_avg_4x4(tmp4, tmp5, tmp6, tmp7, res4, res5, res6, res7,
                        conv_params->fwd_offset, conv_params->bck_offset,
                        sub_const_vec, bits, conv_params->use_dist_wtd_comp_avg,
                        &tmp_shift0, &tmp_shift1);

        vst1_lane_u32((uint32_t *)(dst8_1), vreinterpret_u32_u8(tmp_shift0), 0);
        dst8_1 += dst8_stride;
        vst1_lane_u32((uint32_t *)(dst8_1), vreinterpret_u32_u8(tmp_shift0), 1);
        dst8_1 += dst8_stride;
        vst1_lane_u32((uint32_t *)(dst8_1), vreinterpret_u32_u8(tmp_shift1), 0);
        dst8_1 += dst8_stride;
        vst1_lane_u32((uint32_t *)(dst8_1), vreinterpret_u32_u8(tmp_shift1), 1);

      } else {
        vst1_u16(dst_1, res4);
        dst_1 += dst_stride;
        vst1_u16(dst_1, res5);
        dst_1 += dst_stride;
        vst1_u16(dst_1, res6);
        dst_1 += dst_stride;
        vst1_u16(dst_1, res7);
      }
      src += src_stride * 4;
      dst += dst_stride * 4;
      dst8 += dst8_stride * 4;
    }
  }
}

#if defined(__aarch64__) && defined(__ARM_FEATURE_DOTPROD)

void av1_dist_wtd_convolve_x_neon(const uint8_t *src, int src_stride,
                                  uint8_t *dst8, int dst8_stride, int w, int h,
                                  const InterpFilterParams *filter_params_x,
                                  const int subpel_x_qn,
                                  ConvolveParams *conv_params) {
  assert(!(w % 4));
  assert(!(h % 4));

  const int horiz_offset = filter_params_x->taps / 2 - 1;
  const int bits = FILTER_BITS - conv_params->round_1;
  const int bd = 8;
  const int offset_bits = bd + 2 * FILTER_BITS - conv_params->round_0;
  const int round_offset = (1 << (offset_bits - conv_params->round_1)) +
                           (1 << (offset_bits - conv_params->round_1 - 1));
  const int round_bits =
      2 * FILTER_BITS - conv_params->round_0 - conv_params->round_1;
  const uint16_t fwd_offset = conv_params->fwd_offset;
  const uint16_t bck_offset = conv_params->bck_offset;
  const int use_dist_wtd_comp_avg = conv_params->use_dist_wtd_comp_avg;
  const int16x4_t round_offset64 = vdup_n_s16(round_offset);
  const int16x8_t round_offset128 = vdupq_n_s16(round_offset);
  const int16x8_t shift_round_0 = vdupq_n_s16(-conv_params->round_0 + 1);
  const int16x8_t horiz_const = vdupq_n_s16(bits);

  // Horizontal filter.
  const int16_t *x_filter_ptr = av1_get_interp_filter_subpel_kernel(
      filter_params_x, subpel_x_qn & SUBPEL_MASK);
  // Filter values are even, so downshift by 1 to reduce intermediate precision
  // requirements.
  const int8x8_t x_filter = vshrn_n_s16(vld1q_s16(x_filter_ptr), 1);
  // Dot-product constants.
  const uint8x16_t range_limit = vdupq_n_u8(128);
  const int32_t correction_s32 = vaddlvq_s16(vshll_n_s8(x_filter, 7));
  const int32x4_t correction = vdupq_n_s32(correction_s32);

  const uint8_t *src_ptr = src - horiz_offset;
  CONV_BUF_TYPE *dst = conv_params->dst;
  CONV_BUF_TYPE *dst_ptr = dst;
  uint8_t *dst_u8_ptr = dst8;
  int dst_stride = conv_params->dst_stride;
  int width = w;
  int height = h;

  if (w == 4) {
    const uint8x16x2_t permute_tbl = vld1q_u8_x2(dot_prod_permute_tbl);

    do {
      uint8x16_t s0, s1, s2, s3;
      int32x4_t d0, d1, d2, d3;
      int16x8_t d01, d23;
      uint16x4_t dd0, dd1, dd2, dd3;
      uint8x8_t d01_u8, d23_u8;

      s0 = vld1q_u8(src_ptr + 0 * src_stride);
      s1 = vld1q_u8(src_ptr + 1 * src_stride);
      s2 = vld1q_u8(src_ptr + 2 * src_stride);
      s3 = vld1q_u8(src_ptr + 3 * src_stride);

      d0 = convolve8_4_dot_s16(s0, x_filter, correction, range_limit,
                               permute_tbl);
      d1 = convolve8_4_dot_s16(s1, x_filter, correction, range_limit,
                               permute_tbl);
      d2 = convolve8_4_dot_s16(s2, x_filter, correction, range_limit,
                               permute_tbl);
      d3 = convolve8_4_dot_s16(s3, x_filter, correction, range_limit,
                               permute_tbl);

      d01 = vcombine_s16(vmovn_s32(d0), vmovn_s32(d1));
      d23 = vcombine_s16(vmovn_s32(d2), vmovn_s32(d3));

      d01 = vqrshlq_s16(d01, shift_round_0);
      d23 = vqrshlq_s16(d23, shift_round_0);

      d01 = vrshlq_s16(d01, horiz_const);
      d23 = vrshlq_s16(d23, horiz_const);

      d01 = vaddq_s16(d01, round_offset128);
      d23 = vaddq_s16(d23, round_offset128);

      if (conv_params->do_average) {
        dd0 = vld1_u16(dst_ptr);
        dst_ptr += dst_stride;
        dd1 = vld1_u16(dst_ptr);
        dst_ptr += dst_stride;
        dd2 = vld1_u16(dst_ptr);
        dst_ptr += dst_stride;
        dd3 = vld1_u16(dst_ptr);
        dst_ptr += dst_stride;

        compute_avg_4x4(dd0, dd1, dd2, dd3,
                        vreinterpret_u16_s16(vget_low_s16(d01)),
                        vreinterpret_u16_s16(vget_high_s16(d01)),
                        vreinterpret_u16_s16(vget_low_s16(d23)),
                        vreinterpret_u16_s16(vget_high_s16(d23)), fwd_offset,
                        bck_offset, round_offset64, round_bits,
                        use_dist_wtd_comp_avg, &d01_u8, &d23_u8);

        vst1_lane_u32((uint32_t *)dst_u8_ptr, vreinterpret_u32_u8(d01_u8), 0);
        dst_u8_ptr += dst8_stride;
        vst1_lane_u32((uint32_t *)dst_u8_ptr, vreinterpret_u32_u8(d01_u8), 1);
        dst_u8_ptr += dst8_stride;
        vst1_lane_u32((uint32_t *)dst_u8_ptr, vreinterpret_u32_u8(d23_u8), 0);
        dst_u8_ptr += dst8_stride;
        vst1_lane_u32((uint32_t *)dst_u8_ptr, vreinterpret_u32_u8(d23_u8), 1);
        dst_u8_ptr += dst8_stride;
      } else {
        vst1q_lane_u64((uint64_t *)dst_ptr, vreinterpretq_u64_s16(d01), 0);
        dst_ptr += dst_stride;
        vst1q_lane_u64((uint64_t *)dst_ptr, vreinterpretq_u64_s16(d01), 1);
        dst_ptr += dst_stride;
        vst1q_lane_u64((uint64_t *)dst_ptr, vreinterpretq_u64_s16(d23), 0);
        dst_ptr += dst_stride;
        vst1q_lane_u64((uint64_t *)dst_ptr, vreinterpretq_u64_s16(d23), 1);
        dst_ptr += dst_stride;
      }

      src_ptr += 4 * src_stride;
      height -= 4;
    } while (height > 0);
  } else {
    const uint8x16x3_t permute_tbl = vld1q_u8_x3(dot_prod_permute_tbl);

    do {
      const uint8_t *s = src_ptr;
      CONV_BUF_TYPE *d = dst_ptr;
      uint8_t *d_u8 = dst_u8_ptr;
      width = w;

      do {
        uint8x16_t s0, s1, s2, s3;
        int16x8_t d0, d1, d2, d3;
        uint16x8_t dd0, dd1, dd2, dd3;
        uint8x8_t d0_u8, d1_u8, d2_u8, d3_u8;

        s0 = vld1q_u8(s + 0 * src_stride);
        s1 = vld1q_u8(s + 1 * src_stride);
        s2 = vld1q_u8(s + 2 * src_stride);
        s3 = vld1q_u8(s + 3 * src_stride);

        d0 = convolve8_8_dot_s16(s0, x_filter, correction, range_limit,
                                 permute_tbl, shift_round_0);
        d1 = convolve8_8_dot_s16(s1, x_filter, correction, range_limit,
                                 permute_tbl, shift_round_0);
        d2 = convolve8_8_dot_s16(s2, x_filter, correction, range_limit,
                                 permute_tbl, shift_round_0);
        d3 = convolve8_8_dot_s16(s3, x_filter, correction, range_limit,
                                 permute_tbl, shift_round_0);

        d0 = vrshlq_s16(d0, horiz_const);
        d1 = vrshlq_s16(d1, horiz_const);
        d2 = vrshlq_s16(d2, horiz_const);
        d3 = vrshlq_s16(d3, horiz_const);

        d0 = vaddq_s16(d0, round_offset128);
        d1 = vaddq_s16(d1, round_offset128);
        d2 = vaddq_s16(d2, round_offset128);
        d3 = vaddq_s16(d3, round_offset128);

        if (conv_params->do_average) {
          load_u16_8x4(d, dst_stride, &dd0, &dd1, &dd2, &dd3);

          compute_avg_8x4(dd0, dd1, dd2, dd3, vreinterpretq_u16_s16(d0),
                          vreinterpretq_u16_s16(d1), vreinterpretq_u16_s16(d2),
                          vreinterpretq_u16_s16(d3), fwd_offset, bck_offset,
                          round_offset64, round_bits, use_dist_wtd_comp_avg,
                          &d0_u8, &d1_u8, &d2_u8, &d3_u8);

          store_u8_8x4(d_u8, dst8_stride, d0_u8, d1_u8, d2_u8, d3_u8);
        } else {
          store_u16_8x4(d, dst_stride, vreinterpretq_u16_s16(d0),
                        vreinterpretq_u16_s16(d1), vreinterpretq_u16_s16(d2),
                        vreinterpretq_u16_s16(d3));
        }

        s += 8;
        d += 8;
        d_u8 += 8;
        width -= 8;
      } while (width > 0);

      src_ptr += 4 * src_stride;
      dst_ptr += 4 * dst_stride;
      dst_u8_ptr += 4 * dst8_stride;
      height -= 4;
    } while (height > 0);
  }
}

#else  // !(defined(__aarch64__) && defined(__ARM_FEATURE_DOTPROD))

void av1_dist_wtd_convolve_x_neon(const uint8_t *src, int src_stride,
                                  uint8_t *dst8, int dst8_stride, int w, int h,
                                  const InterpFilterParams *filter_params_x,
                                  const int subpel_x_qn,
                                  ConvolveParams *conv_params) {
  assert(!(w % 4));
  assert(!(h % 4));

  CONV_BUF_TYPE *dst = conv_params->dst;
  int dst_stride = conv_params->dst_stride;
  const int horiz_offset = filter_params_x->taps / 2 - 1;
  const int bits = FILTER_BITS - conv_params->round_1;
  const int bd = 8;
  const int offset_bits = bd + 2 * FILTER_BITS - conv_params->round_0;
  const int round_offset = (1 << (offset_bits - conv_params->round_1)) +
                           (1 << (offset_bits - conv_params->round_1 - 1));
  const int round_bits =
      2 * FILTER_BITS - conv_params->round_0 - conv_params->round_1;
  const uint16_t fwd_offset = conv_params->fwd_offset;
  const uint16_t bck_offset = conv_params->bck_offset;
  const int use_dist_wtd_comp_avg = conv_params->use_dist_wtd_comp_avg;

  // horizontal filter
  const int16_t *x_filter_ptr = av1_get_interp_filter_subpel_kernel(
      filter_params_x, subpel_x_qn & SUBPEL_MASK);

  const uint8_t *src_ptr = src - horiz_offset;

  // Filter values are even, so downshift by 1 to reduce intermediate precision
  // requirements.
  const int16x8_t x_filter = vshrq_n_s16(vld1q_s16(x_filter_ptr), 1);

  const uint8_t *s;
  uint8_t *d_u8;
  uint8_t *dst_u8_ptr;
  CONV_BUF_TYPE *d, *dst_ptr;
  int width, height;
  uint8x8_t t0;
#if defined(__aarch64__)
  uint8x8_t t1, t2, t3, t4, t5, t6, t7;
#endif
  s = src_ptr;
  dst_ptr = dst;
  dst_u8_ptr = dst8;
  width = w;
  height = h;

  if ((w == 4) || (h == 4)) {
    int16x4_t s0, s1, s2, s3, s4, s5, s6, s7, d0;
    int16x8_t tt0;
    uint16x4_t res4;
#if defined(__aarch64__)
    int16x4_t s8, s9, s10, d1, d2, d3;
    int16x8_t tt1, tt2, tt3;
    uint16x4_t res5, res6, res7;
    uint32x2_t tu0 = vdup_n_u32(0), tu1 = vdup_n_u32(0);
    int16x8_t u0, u1;
#else
    int16x4_t temp_0;
#endif
    const int16x4_t zero = vdup_n_s16(0);
    const int16x4_t round_offset_vec = vdup_n_s16(round_offset);
    const int16x4_t shift_round_0 = vdup_n_s16(-conv_params->round_0 + 1);
    const int16x4_t horiz_const = vdup_n_s16(bits);
    do {
      s = src_ptr;
      d = dst_ptr;
      d_u8 = dst_u8_ptr;
      width = w;
      __builtin_prefetch(s + 0 * src_stride);
#if defined(__aarch64__)
      __builtin_prefetch(s + 1 * src_stride);
      __builtin_prefetch(s + 2 * src_stride);
      __builtin_prefetch(s + 3 * src_stride);

      load_u8_8x4(s, src_stride, &t0, &t1, &t2, &t3);
      transpose_u8_8x4(&t0, &t1, &t2, &t3);
      tt0 = vreinterpretq_s16_u16(vmovl_u8(t0));
      tt1 = vreinterpretq_s16_u16(vmovl_u8(t1));
      tt2 = vreinterpretq_s16_u16(vmovl_u8(t2));
      tt3 = vreinterpretq_s16_u16(vmovl_u8(t3));
      s0 = vget_low_s16(tt0);
      s1 = vget_low_s16(tt1);
      s2 = vget_low_s16(tt2);
      s3 = vget_low_s16(tt3);
      s4 = vget_high_s16(tt0);
      s5 = vget_high_s16(tt1);
      s6 = vget_high_s16(tt2);
      __builtin_prefetch(d + 0 * dst_stride);
      __builtin_prefetch(d + 1 * dst_stride);
      __builtin_prefetch(d + 2 * dst_stride);
      __builtin_prefetch(d + 3 * dst_stride);
      s += 7;
      do {
        load_unaligned_u8_4x4(s, src_stride, &tu0, &tu1);
        t0 = vreinterpret_u8_u32(tu0);
        t1 = vreinterpret_u8_u32(tu1);

        transpose_u8_4x4(&t0, &t1);
        u0 = vreinterpretq_s16_u16(vmovl_u8(t0));
        u1 = vreinterpretq_s16_u16(vmovl_u8(t1));

        s7 = vget_low_s16(u0);
        s8 = vget_low_s16(u1);
        s9 = vget_high_s16(u0);
        s10 = vget_high_s16(u1);

        d0 = convolve8_4x4_s16(s0, s1, s2, s3, s4, s5, s6, s7, x_filter, zero,
                               shift_round_0);
        d0 = vrshl_s16(d0, horiz_const);
        d0 = vadd_s16(d0, round_offset_vec);
        d1 = convolve8_4x4_s16(s1, s2, s3, s4, s5, s6, s7, s8, x_filter, zero,
                               shift_round_0);
        d1 = vrshl_s16(d1, horiz_const);
        d1 = vadd_s16(d1, round_offset_vec);
        d2 = convolve8_4x4_s16(s2, s3, s4, s5, s6, s7, s8, s9, x_filter, zero,
                               shift_round_0);
        d2 = vrshl_s16(d2, horiz_const);
        d2 = vadd_s16(d2, round_offset_vec);
        d3 = convolve8_4x4_s16(s3, s4, s5, s6, s7, s8, s9, s10, x_filter, zero,
                               shift_round_0);
        d3 = vrshl_s16(d3, horiz_const);
        d3 = vadd_s16(d3, round_offset_vec);

        transpose_s16_4x4d(&d0, &d1, &d2, &d3);

        if (conv_params->do_average) {
          __builtin_prefetch(d + 0 * dst_stride);
          __builtin_prefetch(d + 1 * dst_stride);
          __builtin_prefetch(d + 2 * dst_stride);
          __builtin_prefetch(d + 3 * dst_stride);

          __builtin_prefetch(d_u8 + 0 * dst8_stride);
          __builtin_prefetch(d_u8 + 1 * dst8_stride);
          __builtin_prefetch(d_u8 + 2 * dst8_stride);
          __builtin_prefetch(d_u8 + 3 * dst8_stride);

          load_u16_4x4(d, dst_stride, &res4, &res5, &res6, &res7);

          compute_avg_4x4(res4, res5, res6, res7, vreinterpret_u16_s16(d0),
                          vreinterpret_u16_s16(d1), vreinterpret_u16_s16(d2),
                          vreinterpret_u16_s16(d3), fwd_offset, bck_offset,
                          round_offset_vec, round_bits, use_dist_wtd_comp_avg,
                          &t0, &t1);

          vst1_lane_u32((uint32_t *)d_u8, vreinterpret_u32_u8(t0),
                        0);  // 00 01 02 03
          vst1_lane_u32((uint32_t *)(d_u8 + dst8_stride),
                        vreinterpret_u32_u8(t0),
                        1);  // 10 11 12 13
          vst1_lane_u32((uint32_t *)(d_u8 + 2 * dst8_stride),
                        vreinterpret_u32_u8(t1),
                        0);  // 20 21 22 23
          vst1_lane_u32((uint32_t *)(d_u8 + 3 * dst8_stride),
                        vreinterpret_u32_u8(t1),
                        1);  // 30 31 32 33
        } else {
          store_u16_4x4(d, dst_stride, vreinterpret_u16_s16(d0),
                        vreinterpret_u16_s16(d1), vreinterpret_u16_s16(d2),
                        vreinterpret_u16_s16(d3));
        }

        s0 = s4;
        s1 = s5;
        s2 = s6;
        s3 = s7;
        s4 = s8;
        s5 = s9;
        s6 = s10;

        s += 4;
        width -= 4;
        d += 4;
        d_u8 += 4;
      } while (width > 0);
      src_ptr += (src_stride << 2);
      dst_ptr += (dst_stride << 2);
      dst_u8_ptr += (dst8_stride << 2);
      height -= 4;
#else
      t0 = vld1_u8(s);                            // a0 a1 a2 a3 a4 a5 a6 a7
      tt0 = vreinterpretq_s16_u16(vmovl_u8(t0));  // a0 a1 a2 a3 a4 a5 a6 a7
      s0 = vget_low_s16(tt0);                     // a0 a1 a2 a3
      s4 = vget_high_s16(tt0);                    // a4 a5 a6 a7
      __builtin_prefetch(d);

      s += 8;
      do {
        t0 = vld1_u8(s);  // a8 a9 a10 a11

        // a8 a9 a10 a11
        s7 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t0)));
        temp_0 = s7;
        s1 = vext_s16(s0, s4, 1);  // a1 a2 a3 a4
        s2 = vext_s16(s0, s4, 2);  // a2 a3 a4 a5
        s3 = vext_s16(s0, s4, 3);  // a3 a4 a5 a6
        s5 = vext_s16(s4, s7, 1);  // a5 a6 a7 a8
        s6 = vext_s16(s4, s7, 2);  // a6 a7 a8 a9
        s7 = vext_s16(s4, s7, 3);  // a7 a8 a9 a10

        d0 = convolve8_4x4_s16(s0, s1, s2, s3, s4, s5, s6, s7, x_filter, zero,
                               shift_round_0);
        d0 = vrshl_s16(d0, horiz_const);
        d0 = vadd_s16(d0, round_offset_vec);
        s0 = s4;
        s4 = temp_0;
        if (conv_params->do_average) {
          __builtin_prefetch(d);
          __builtin_prefetch(d_u8);

          res4 = vld1_u16(d);

          compute_avg_4x1(res4, vreinterpret_u16_s16(d0), fwd_offset,
                          bck_offset, round_offset_vec, round_bits,
                          use_dist_wtd_comp_avg, &t0);

          vst1_lane_u32((uint32_t *)d_u8, vreinterpret_u32_u8(t0),
                        0);  // 00 01 02 03
        } else {
          vst1_u16(d, vreinterpret_u16_s16(d0));
        }

        s += 4;
        width -= 4;
        d += 4;
        d_u8 += 4;
      } while (width > 0);
      src_ptr += (src_stride);
      dst_ptr += (dst_stride);
      dst_u8_ptr += (dst8_stride);
      height--;
#endif
    } while (height > 0);
  } else {
    CONV_BUF_TYPE *d_tmp;
    uint8_t *d_u8_tmp;
    int16x8_t s0, s1, s2, s3, s4, s5, s6, s7;
    int16x8_t res0;
    uint16x8_t res8;
    const int16x8_t round_offset128 = vdupq_n_s16(round_offset);
    const int16x4_t round_offset64 = vdup_n_s16(round_offset);
    const int16x8_t shift_round_0 = vdupq_n_s16(-conv_params->round_0 + 1);
    const int16x8_t horiz_const = vdupq_n_s16(bits);
    const int16x8_t zero = vdupq_n_s16(0);

    d = dst_ptr = dst;
    d_u8 = dst_u8_ptr = dst8;
    do {
#if defined(__aarch64__)
      int16x8_t s11, s12, s13, s14;
      int16x8_t s8, s9, s10;
      int16x8_t res1, res2, res3, res4, res5, res6, res7;
      uint16x8_t res9, res10, res11;
      __builtin_prefetch(src_ptr + 0 * src_stride);
      __builtin_prefetch(src_ptr + 1 * src_stride);
      __builtin_prefetch(src_ptr + 2 * src_stride);
      __builtin_prefetch(src_ptr + 3 * src_stride);
      __builtin_prefetch(src_ptr + 4 * src_stride);
      __builtin_prefetch(src_ptr + 5 * src_stride);
      __builtin_prefetch(src_ptr + 6 * src_stride);
      __builtin_prefetch(src_ptr + 7 * src_stride);
      load_u8_8x8(src_ptr, src_stride, &t0, &t1, &t2, &t3, &t4, &t5, &t6, &t7);
      transpose_u8_8x8(&t0, &t1, &t2, &t3, &t4, &t5, &t6, &t7);
      s0 = vreinterpretq_s16_u16(vmovl_u8(t0));
      s1 = vreinterpretq_s16_u16(vmovl_u8(t1));
      s2 = vreinterpretq_s16_u16(vmovl_u8(t2));
      s3 = vreinterpretq_s16_u16(vmovl_u8(t3));
      s4 = vreinterpretq_s16_u16(vmovl_u8(t4));
      s5 = vreinterpretq_s16_u16(vmovl_u8(t5));
      s6 = vreinterpretq_s16_u16(vmovl_u8(t6));

      width = w;
      s = src_ptr + 7;
      d = dst_ptr;
      d_u8_tmp = dst_u8_ptr;

      __builtin_prefetch(dst_ptr + 0 * dst_stride);
      __builtin_prefetch(dst_ptr + 1 * dst_stride);
      __builtin_prefetch(dst_ptr + 2 * dst_stride);
      __builtin_prefetch(dst_ptr + 3 * dst_stride);
      __builtin_prefetch(dst_ptr + 4 * dst_stride);
      __builtin_prefetch(dst_ptr + 5 * dst_stride);
      __builtin_prefetch(dst_ptr + 6 * dst_stride);
      __builtin_prefetch(dst_ptr + 7 * dst_stride);

      do {
        d_u8 = d_u8_tmp;
        d_tmp = d;

        load_u8_8x8(s, src_stride, &t0, &t1, &t2, &t3, &t4, &t5, &t6, &t7);
        transpose_u8_8x8(&t0, &t1, &t2, &t3, &t4, &t5, &t6, &t7);
        s7 = vreinterpretq_s16_u16(vmovl_u8(t0));
        s8 = vreinterpretq_s16_u16(vmovl_u8(t1));
        s9 = vreinterpretq_s16_u16(vmovl_u8(t2));
        s10 = vreinterpretq_s16_u16(vmovl_u8(t3));
        s11 = vreinterpretq_s16_u16(vmovl_u8(t4));
        s12 = vreinterpretq_s16_u16(vmovl_u8(t5));
        s13 = vreinterpretq_s16_u16(vmovl_u8(t6));
        s14 = vreinterpretq_s16_u16(vmovl_u8(t7));

        res0 = convolve8_8x8_s16(s0, s1, s2, s3, s4, s5, s6, s7, x_filter, zero,
                                 shift_round_0);

        res0 = vrshlq_s16(res0, horiz_const);
        res0 = vaddq_s16(res0, round_offset128);

        res1 = convolve8_8x8_s16(s1, s2, s3, s4, s5, s6, s7, s8, x_filter, zero,
                                 shift_round_0);
        res1 = vrshlq_s16(res1, horiz_const);
        res1 = vaddq_s16(res1, round_offset128);
        res2 = convolve8_8x8_s16(s2, s3, s4, s5, s6, s7, s8, s9, x_filter, zero,
                                 shift_round_0);
        res2 = vrshlq_s16(res2, horiz_const);
        res2 = vaddq_s16(res2, round_offset128);
        res3 = convolve8_8x8_s16(s3, s4, s5, s6, s7, s8, s9, s10, x_filter,
                                 zero, shift_round_0);
        res3 = vrshlq_s16(res3, horiz_const);
        res3 = vaddq_s16(res3, round_offset128);
        res4 = convolve8_8x8_s16(s4, s5, s6, s7, s8, s9, s10, s11, x_filter,
                                 zero, shift_round_0);
        res4 = vrshlq_s16(res4, horiz_const);
        res4 = vaddq_s16(res4, round_offset128);
        res5 = convolve8_8x8_s16(s5, s6, s7, s8, s9, s10, s11, s12, x_filter,
                                 zero, shift_round_0);
        res5 = vrshlq_s16(res5, horiz_const);
        res5 = vaddq_s16(res5, round_offset128);
        res6 = convolve8_8x8_s16(s6, s7, s8, s9, s10, s11, s12, s13, x_filter,
                                 zero, shift_round_0);
        res6 = vrshlq_s16(res6, horiz_const);
        res6 = vaddq_s16(res6, round_offset128);
        res7 = convolve8_8x8_s16(s7, s8, s9, s10, s11, s12, s13, s14, x_filter,
                                 zero, shift_round_0);
        res7 = vrshlq_s16(res7, horiz_const);
        res7 = vaddq_s16(res7, round_offset128);

        transpose_s16_8x8(&res0, &res1, &res2, &res3, &res4, &res5, &res6,
                          &res7);

        if (conv_params->do_average) {
          load_u16_8x4(d_tmp, dst_stride, &res8, &res9, &res10, &res11);
          d_tmp += (dst_stride << 2);

          compute_avg_8x4(res8, res9, res10, res11, vreinterpretq_u16_s16(res0),
                          vreinterpretq_u16_s16(res1),
                          vreinterpretq_u16_s16(res2),
                          vreinterpretq_u16_s16(res3), fwd_offset, bck_offset,
                          round_offset64, round_bits, use_dist_wtd_comp_avg,
                          &t0, &t1, &t2, &t3);

          store_u8_8x4(d_u8, dst8_stride, t0, t1, t2, t3);
          d_u8 += (dst8_stride << 2);

          load_u16_8x4(d_tmp, dst_stride, &res8, &res9, &res10, &res11);
          d_tmp += (dst_stride << 2);

          compute_avg_8x4(res8, res9, res10, res11, vreinterpretq_u16_s16(res4),
                          vreinterpretq_u16_s16(res5),
                          vreinterpretq_u16_s16(res6),
                          vreinterpretq_u16_s16(res7), fwd_offset, bck_offset,
                          round_offset64, round_bits, use_dist_wtd_comp_avg,
                          &t0, &t1, &t2, &t3);

          store_u8_8x4(d_u8, dst8_stride, t0, t1, t2, t3);
          d_u8 += (dst8_stride << 2);
        } else {
          store_u16_8x8(
              d_tmp, dst_stride, vreinterpretq_u16_s16(res0),
              vreinterpretq_u16_s16(res1), vreinterpretq_u16_s16(res2),
              vreinterpretq_u16_s16(res3), vreinterpretq_u16_s16(res4),
              vreinterpretq_u16_s16(res5), vreinterpretq_u16_s16(res6),
              vreinterpretq_u16_s16(res7));
          d_tmp += (dst_stride << 3);
        }

        s0 = s8;
        s1 = s9;
        s2 = s10;
        s3 = s11;
        s4 = s12;
        s5 = s13;
        s6 = s14;
        s += 8;
        d += 8;
        width -= 8;
        d_u8_tmp += 8;
      } while (width > 0);
      src_ptr += 8 * src_stride;
      dst_ptr += 8 * dst_stride;
      dst_u8_ptr += 8 * dst8_stride;
      height -= 8;
#else
      int16x8_t temp_0;
      __builtin_prefetch(src_ptr);
      t0 = vld1_u8(src_ptr);
      s0 = vreinterpretq_s16_u16(vmovl_u8(t0));  // a0 a1 a2 a3 a4 a5 a6 a7

      width = w;
      s = src_ptr + 8;
      d = dst_ptr;
      d_u8_tmp = dst_u8_ptr;

      __builtin_prefetch(dst_ptr);

      do {
        d_u8 = d_u8_tmp;
        d_tmp = d;

        t0 = vld1_u8(s);  // a8 a9 a10 a11 a12 a13 a14 a15
        s7 = vreinterpretq_s16_u16(vmovl_u8(t0));
        temp_0 = s0;
        s0 = s7;

        s1 = vextq_s16(temp_0, s7, 1);  // a1 a2 a3 a4 a5 a6 a7 a8
        s2 = vextq_s16(temp_0, s7, 2);  // a2 a3 a4 a5 a6 a7 a8 a9
        s3 = vextq_s16(temp_0, s7, 3);  // a3 a4 a5 a6 a7 a8 a9 a10
        s4 = vextq_s16(temp_0, s7, 4);  // a4 a5 a6 a7 a8 a9 a10 a11
        s5 = vextq_s16(temp_0, s7, 5);  // a5 a6 a7 a8 a9 a10 a11 a12
        s6 = vextq_s16(temp_0, s7, 6);  // a6 a7 a8 a9 a10 a11 a12 a13
        s7 = vextq_s16(temp_0, s7, 7);  // a7 a8 a9 a10 a11 a12 a13 a14

        res0 = convolve8_8x8_s16(temp_0, s1, s2, s3, s4, s5, s6, s7, x_filter,
                                 zero, shift_round_0);

        res0 = vrshlq_s16(res0, horiz_const);
        res0 = vaddq_s16(res0, round_offset128);

        if (conv_params->do_average) {
          res8 = vld1q_u16(d_tmp);
          d_tmp += (dst_stride);

          compute_avg_8x1(res8, vreinterpretq_u16_s16(res0), fwd_offset,
                          bck_offset, round_offset64, round_bits,
                          use_dist_wtd_comp_avg, &t0);

          vst1_u8(d_u8, t0);
          d_u8 += (dst8_stride);
        } else {
          vst1q_u16(d_tmp, vreinterpretq_u16_s16(res0));
          d_tmp += (dst_stride);
        }

        s += 8;
        d += 8;
        width -= 8;
        d_u8_tmp += 8;
      } while (width > 0);
      src_ptr += src_stride;
      dst_ptr += dst_stride;
      dst_u8_ptr += dst8_stride;
      height--;
#endif
    } while (height > 0);
  }
}

#endif  // defined(__aarch64__) && defined(__ARM_FEATURE_DOTPROD)

void av1_dist_wtd_convolve_y_neon(const uint8_t *src, int src_stride,
                                  uint8_t *dst8, int dst8_stride, int w, int h,
                                  const InterpFilterParams *filter_params_y,
                                  const int subpel_y_qn,
                                  ConvolveParams *conv_params) {
  assert(!(w % 4));
  assert(!(h % 4));

  CONV_BUF_TYPE *dst = conv_params->dst;
  const int dst_stride = conv_params->dst_stride;
  const int vert_offset = filter_params_y->taps / 2 - 1;
  const int bits = FILTER_BITS - conv_params->round_0;
  const int bd = 8;
  const int offset_bits = bd + 2 * FILTER_BITS - conv_params->round_0;
  const int round_offset = (1 << (offset_bits - conv_params->round_1)) +
                           (1 << (offset_bits - conv_params->round_1 - 1));
  const int round_bits =
      2 * FILTER_BITS - conv_params->round_0 - conv_params->round_1;
  const uint16_t fwd_offset = conv_params->fwd_offset;
  const uint16_t bck_offset = conv_params->bck_offset;
  const int use_dist_wtd_comp_avg = conv_params->use_dist_wtd_comp_avg;
  const int shift_value = (conv_params->round_1 - 1 - bits);

  // vertical filter
  const int16_t *y_filter_ptr = av1_get_interp_filter_subpel_kernel(
      filter_params_y, subpel_y_qn & SUBPEL_MASK);

  const uint8_t *src_ptr = src - (vert_offset * src_stride);

  // Filter values are even, so downshift by 1 to reduce intermediate precision
  // requirements.
  const int16x8_t y_filter = vshrq_n_s16(vld1q_s16(y_filter_ptr), 1);

  const uint8_t *s;
  uint8_t *d_u8;
  uint8_t *dst_u8_ptr;
  CONV_BUF_TYPE *d, *dst_ptr;
  int width, height;

  s = src_ptr;
  dst_ptr = dst;
  dst_u8_ptr = dst8;
  width = w;
  height = h;

  // used to get rid of multiplication = (vertical filter output sum) *
  // (1<<bits).
  assert((conv_params->round_1 - 2) >= bits);

  if ((w == 4) || (h == 4)) {
    int16x4_t s0, s1, s2, s3, s4, s5, s6, s7, d0;
    uint16x4_t res4;
    uint32x2_t tu0 = vdup_n_u32(0), tu1 = vdup_n_u32(0), tu2 = vdup_n_u32(0),
               tu3 = vdup_n_u32(0);
    int16x8_t u0, u1, u2, u3;
    uint8x8_t t0;

#if defined(__aarch64__)
    int16x4_t s8, s9, s10, d1, d2, d3;
    uint16x4_t res5, res6, res7;
    uint8x8_t t1;
#endif
    const int16x4_t round_offset64 = vdup_n_s16(round_offset);
    const int16x4_t shift_vec = vdup_n_s16(-shift_value);
    const int16x4_t zero = vdup_n_s16(0);

    do {
      s = src_ptr;
      d = dst_ptr;
      d_u8 = dst_u8_ptr;
      height = h;
      __builtin_prefetch(s + 0 * src_stride);
      __builtin_prefetch(s + 1 * src_stride);
      __builtin_prefetch(s + 2 * src_stride);
      __builtin_prefetch(s + 3 * src_stride);

      load_unaligned_u8_4x8(s, src_stride, &tu0, &tu1, &tu2, &tu3);

      u0 = vreinterpretq_s16_u16(vmovl_u8(vreinterpret_u8_u32(tu0)));
      u1 = vreinterpretq_s16_u16(vmovl_u8(vreinterpret_u8_u32(tu1)));
      u2 = vreinterpretq_s16_u16(vmovl_u8(vreinterpret_u8_u32(tu2)));
      u3 = vreinterpretq_s16_u16(vmovl_u8(vreinterpret_u8_u32(tu3)));

      s0 = vget_low_s16(u0);
      s1 = vget_high_s16(u0);
      s2 = vget_low_s16(u1);
      s3 = vget_high_s16(u1);
      s4 = vget_low_s16(u2);
      s5 = vget_high_s16(u2);
      s6 = vget_low_s16(u3);

      __builtin_prefetch(d + 0 * dst_stride);
      __builtin_prefetch(d + 1 * dst_stride);
      __builtin_prefetch(d + 2 * dst_stride);
      __builtin_prefetch(d + 3 * dst_stride);

      s += (7 * src_stride);
      do {
#if defined(__aarch64__)
        load_unaligned_u8_4x4(s, src_stride, &tu0, &tu1);

        u0 = vreinterpretq_s16_u16(vmovl_u8(vreinterpret_u8_u32(tu0)));
        u1 = vreinterpretq_s16_u16(vmovl_u8(vreinterpret_u8_u32(tu1)));

        s7 = vget_low_s16(u0);
        s8 = vget_high_s16(u0);
        s9 = vget_low_s16(u1);
        s10 = vget_high_s16(u1);

        d0 = convolve8_4x4_s16(s0, s1, s2, s3, s4, s5, s6, s7, y_filter, zero,
                               shift_vec);
        d0 = vadd_s16(d0, round_offset64);
        d1 = convolve8_4x4_s16(s1, s2, s3, s4, s5, s6, s7, s8, y_filter, zero,
                               shift_vec);
        d1 = vadd_s16(d1, round_offset64);
        d2 = convolve8_4x4_s16(s2, s3, s4, s5, s6, s7, s8, s9, y_filter, zero,
                               shift_vec);
        d2 = vadd_s16(d2, round_offset64);
        d3 = convolve8_4x4_s16(s3, s4, s5, s6, s7, s8, s9, s10, y_filter, zero,
                               shift_vec);
        d3 = vadd_s16(d3, round_offset64);

        if (conv_params->do_average) {
          __builtin_prefetch(d + 0 * dst_stride);
          __builtin_prefetch(d + 1 * dst_stride);
          __builtin_prefetch(d + 2 * dst_stride);
          __builtin_prefetch(d + 3 * dst_stride);

          __builtin_prefetch(d_u8 + 0 * dst8_stride);
          __builtin_prefetch(d_u8 + 1 * dst8_stride);
          __builtin_prefetch(d_u8 + 2 * dst8_stride);
          __builtin_prefetch(d_u8 + 3 * dst8_stride);

          load_u16_4x4(d, dst_stride, &res4, &res5, &res6, &res7);
          d += (dst_stride << 2);

          compute_avg_4x4(res4, res5, res6, res7, vreinterpret_u16_s16(d0),
                          vreinterpret_u16_s16(d1), vreinterpret_u16_s16(d2),
                          vreinterpret_u16_s16(d3), fwd_offset, bck_offset,
                          round_offset64, round_bits, use_dist_wtd_comp_avg,
                          &t0, &t1);

          vst1_lane_u32((uint32_t *)d_u8, vreinterpret_u32_u8(t0), 0);
          d_u8 += dst8_stride;
          vst1_lane_u32((uint32_t *)d_u8, vreinterpret_u32_u8(t0), 1);
          d_u8 += dst8_stride;
          vst1_lane_u32((uint32_t *)d_u8, vreinterpret_u32_u8(t1), 0);
          d_u8 += dst8_stride;
          vst1_lane_u32((uint32_t *)d_u8, vreinterpret_u32_u8(t1), 1);
          d_u8 += dst8_stride;
        } else {
          store_u16_4x4(d, dst_stride, vreinterpret_u16_s16(d0),
                        vreinterpret_u16_s16(d1), vreinterpret_u16_s16(d2),
                        vreinterpret_u16_s16(d3));
          d += (dst_stride << 2);
        }

        s0 = s4;
        s1 = s5;
        s2 = s6;
        s3 = s7;
        s4 = s8;
        s5 = s9;
        s6 = s10;

        s += (src_stride << 2);
        height -= 4;
#else
        load_unaligned_u8_4x1(s, src_stride, &tu0);
        u0 = vreinterpretq_s16_u16(vmovl_u8(vreinterpret_u8_u32(tu0)));
        s7 = vget_low_s16(u0);

        d0 = convolve8_4x4_s16(s0, s1, s2, s3, s4, s5, s6, s7, y_filter, zero,
                               shift_vec);

        d0 = vadd_s16(d0, round_offset64);

        if (conv_params->do_average) {
          __builtin_prefetch(d);

          res4 = vld1_u16(d);
          d += (dst_stride);

          compute_avg_4x1(res4, vreinterpret_u16_s16(d0), fwd_offset,
                          bck_offset, round_offset64, round_bits,
                          use_dist_wtd_comp_avg, &t0);

          vst1_lane_u32((uint32_t *)d_u8, vreinterpret_u32_u8(t0), 0);
          d_u8 += dst8_stride;
        } else {
          vst1_u16(d, vreinterpret_u16_s16(d0));
          d += (dst_stride);
        }

        s0 = s1;
        s1 = s2;
        s2 = s3;
        s3 = s4;
        s4 = s5;
        s5 = s6;
        s6 = s7;

        s += (src_stride);
        height--;
#endif
      } while (height > 0);
      src_ptr += 4;
      dst_ptr += 4;
      dst_u8_ptr += 4;
      width -= 4;
    } while (width > 0);
  } else {
    CONV_BUF_TYPE *d_tmp;
    int16x8_t s0, s1, s2, s3, s4, s5, s6, s7;
    int16x8_t res0;
    uint16x8_t res8;
    uint8x8_t t0, t1, t2, t3, t4, t5, t6, t7;
    const int16x8_t round_offset128 = vdupq_n_s16(round_offset);
    const int16x8_t shift_vec = vdupq_n_s16(-shift_value);
    const int16x4_t round_offset64 = vdup_n_s16(round_offset);
    const int16x8_t zero = vdupq_n_s16(0);
#if defined(__aarch64__)
    int16x8_t s8, s9, s10, s11, s12, s13, s14;
    int16x8_t res1, res2, res3, res4, res5, res6, res7;
    uint16x8_t res10, res11, res9;
#endif
    dst_ptr = dst;
    dst_u8_ptr = dst8;
    do {
      __builtin_prefetch(src_ptr + 0 * src_stride);
      __builtin_prefetch(src_ptr + 1 * src_stride);
      __builtin_prefetch(src_ptr + 2 * src_stride);
      __builtin_prefetch(src_ptr + 3 * src_stride);
      __builtin_prefetch(src_ptr + 4 * src_stride);
      __builtin_prefetch(src_ptr + 5 * src_stride);
      __builtin_prefetch(src_ptr + 6 * src_stride);
      __builtin_prefetch(src_ptr + 7 * src_stride);
      load_u8_8x8(src_ptr, src_stride, &t0, &t1, &t2, &t3, &t4, &t5, &t6, &t7);

      s0 = vreinterpretq_s16_u16(vmovl_u8(t0));
      s1 = vreinterpretq_s16_u16(vmovl_u8(t1));
      s2 = vreinterpretq_s16_u16(vmovl_u8(t2));
      s3 = vreinterpretq_s16_u16(vmovl_u8(t3));
      s4 = vreinterpretq_s16_u16(vmovl_u8(t4));
      s5 = vreinterpretq_s16_u16(vmovl_u8(t5));
      s6 = vreinterpretq_s16_u16(vmovl_u8(t6));

      height = h;
      s = src_ptr + (7 * src_stride);
      d_tmp = dst_ptr;
      d_u8 = dst_u8_ptr;

      do {
#if defined(__aarch64__)
        load_u8_8x8(s, src_stride, &t0, &t1, &t2, &t3, &t4, &t5, &t6, &t7);

        s7 = vreinterpretq_s16_u16(vmovl_u8(t0));
        s8 = vreinterpretq_s16_u16(vmovl_u8(t1));
        s9 = vreinterpretq_s16_u16(vmovl_u8(t2));
        s10 = vreinterpretq_s16_u16(vmovl_u8(t3));
        s11 = vreinterpretq_s16_u16(vmovl_u8(t4));
        s12 = vreinterpretq_s16_u16(vmovl_u8(t5));
        s13 = vreinterpretq_s16_u16(vmovl_u8(t6));
        s14 = vreinterpretq_s16_u16(vmovl_u8(t7));

        __builtin_prefetch(dst_ptr + 0 * dst_stride);
        __builtin_prefetch(dst_ptr + 1 * dst_stride);
        __builtin_prefetch(dst_ptr + 2 * dst_stride);
        __builtin_prefetch(dst_ptr + 3 * dst_stride);

        res0 = convolve8_8x8_s16(s0, s1, s2, s3, s4, s5, s6, s7, y_filter, zero,
                                 shift_vec);
        res0 = vaddq_s16(res0, round_offset128);
        res1 = convolve8_8x8_s16(s1, s2, s3, s4, s5, s6, s7, s8, y_filter, zero,
                                 shift_vec);
        res1 = vaddq_s16(res1, round_offset128);
        res2 = convolve8_8x8_s16(s2, s3, s4, s5, s6, s7, s8, s9, y_filter, zero,
                                 shift_vec);
        res2 = vaddq_s16(res2, round_offset128);
        res3 = convolve8_8x8_s16(s3, s4, s5, s6, s7, s8, s9, s10, y_filter,
                                 zero, shift_vec);
        res3 = vaddq_s16(res3, round_offset128);
        res4 = convolve8_8x8_s16(s4, s5, s6, s7, s8, s9, s10, s11, y_filter,
                                 zero, shift_vec);
        res4 = vaddq_s16(res4, round_offset128);
        res5 = convolve8_8x8_s16(s5, s6, s7, s8, s9, s10, s11, s12, y_filter,
                                 zero, shift_vec);
        res5 = vaddq_s16(res5, round_offset128);
        res6 = convolve8_8x8_s16(s6, s7, s8, s9, s10, s11, s12, s13, y_filter,
                                 zero, shift_vec);
        res6 = vaddq_s16(res6, round_offset128);
        res7 = convolve8_8x8_s16(s7, s8, s9, s10, s11, s12, s13, s14, y_filter,
                                 zero, shift_vec);
        res7 = vaddq_s16(res7, round_offset128);

        if (conv_params->do_average) {
          __builtin_prefetch(d_tmp + 0 * dst8_stride);
          __builtin_prefetch(d_tmp + 1 * dst8_stride);
          __builtin_prefetch(d_tmp + 2 * dst8_stride);
          __builtin_prefetch(d_tmp + 3 * dst8_stride);

          load_u16_8x4(d_tmp, dst_stride, &res8, &res9, &res10, &res11);
          d_tmp += (dst_stride << 2);

          compute_avg_8x4(res8, res9, res10, res11, vreinterpretq_u16_s16(res0),
                          vreinterpretq_u16_s16(res1),
                          vreinterpretq_u16_s16(res2),
                          vreinterpretq_u16_s16(res3), fwd_offset, bck_offset,
                          round_offset64, round_bits, use_dist_wtd_comp_avg,
                          &t0, &t1, &t2, &t3);

          store_u8_8x4(d_u8, dst8_stride, t0, t1, t2, t3);
          d_u8 += (dst8_stride << 2);

          load_u16_8x4(d_tmp, dst_stride, &res8, &res9, &res10, &res11);
          d_tmp += (dst_stride << 2);

          compute_avg_8x4(res8, res9, res10, res11, vreinterpretq_u16_s16(res4),
                          vreinterpretq_u16_s16(res5),
                          vreinterpretq_u16_s16(res6),
                          vreinterpretq_u16_s16(res7), fwd_offset, bck_offset,
                          round_offset64, round_bits, use_dist_wtd_comp_avg,
                          &t0, &t1, &t2, &t3);

          store_u8_8x4(d_u8, dst8_stride, t0, t1, t2, t3);
          d_u8 += (dst8_stride << 2);
        } else {
          store_u16_8x8(
              d_tmp, dst_stride, vreinterpretq_u16_s16(res0),
              vreinterpretq_u16_s16(res1), vreinterpretq_u16_s16(res2),
              vreinterpretq_u16_s16(res3), vreinterpretq_u16_s16(res4),
              vreinterpretq_u16_s16(res5), vreinterpretq_u16_s16(res6),
              vreinterpretq_u16_s16(res7));
          d_tmp += (dst_stride << 3);
        }

        s0 = s8;
        s1 = s9;
        s2 = s10;
        s3 = s11;
        s4 = s12;
        s5 = s13;
        s6 = s14;
        s += (8 * src_stride);
        height -= 8;
#else
        s7 = vreinterpretq_s16_u16(vmovl_u8(vld1_u8(s)));

        __builtin_prefetch(dst_ptr);

        res0 = convolve8_8x8_s16(s0, s1, s2, s3, s4, s5, s6, s7, y_filter, zero,
                                 shift_vec);
        res0 = vaddq_s16(res0, round_offset128);

        s0 = s1;
        s1 = s2;
        s2 = s3;
        s3 = s4;
        s4 = s5;
        s5 = s6;
        s6 = s7;

        if (conv_params->do_average) {
          __builtin_prefetch(d_tmp);

          res8 = vld1q_u16(d_tmp);
          d_tmp += (dst_stride);

          compute_avg_8x1(res8, vreinterpretq_u16_s16(res0), fwd_offset,
                          bck_offset, round_offset64, round_bits,
                          use_dist_wtd_comp_avg, &t0);

          vst1_u8(d_u8, t0);
          d_u8 += (dst8_stride);
        } else {
          vst1q_u16(d_tmp, vreinterpretq_u16_s16(res0));
          d_tmp += dst_stride;
        }

        s += (src_stride);
        height--;
#endif
      } while (height > 0);
      src_ptr += 8;
      dst_ptr += 8;
      dst_u8_ptr += 8;
      width -= 8;
    } while (width > 0);
  }
}