text: /*
   * Copyright (c) 2016, 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 <smmintrin.h>  // SSE4.1
  
  #include <assert.h>
  
  #include "aom/aom_integer.h"
  #include "aom_ports/mem.h"
  #include "aom_dsp/aom_dsp_common.h"
  #include "aom_dsp/blend.h"
  
  #include "aom_dsp/x86/synonyms.h"
  #include "aom_dsp/x86/blend_sse4.h"
  #include "aom_dsp/x86/blend_mask_sse4.h"
  
  #include "config/aom_dsp_rtcd.h"
  
  //////////////////////////////////////////////////////////////////////////////
  // No sub-sampling
  //////////////////////////////////////////////////////////////////////////////
  
  static void blend_a64_mask_w4_sse4_1(uint8_t *dst, uint32_t dst_stride,
                                       const uint8_t *src0, uint32_t src0_stride,
                                       const uint8_t *src1, uint32_t src1_stride,
                                       const uint8_t *mask, uint32_t mask_stride,
                                       int w, int h) {
    (void)w;
    const __m128i v_maxval_b = _mm_set1_epi8(AOM_BLEND_A64_MAX_ALPHA);
    const __m128i _r = _mm_set1_epi16(1 << (15 - AOM_BLEND_A64_ROUND_BITS));
    do {
      const __m128i v_m0_b = xx_loadl_32(mask);
      const __m128i v_m1_b = _mm_sub_epi8(v_maxval_b, v_m0_b);
      const __m128i v_res_b = blend_4_u8(src0, src1, &v_m0_b, &v_m1_b, &_r);
      xx_storel_32(dst, v_res_b);
  
      dst += dst_stride;
      src0 += src0_stride;
      src1 += src1_stride;
      mask += mask_stride;
    } while (--h);
  }
  
  static void blend_a64_mask_w8_sse4_1(uint8_t *dst, uint32_t dst_stride,
                                       const uint8_t *src0, uint32_t src0_stride,
                                       const uint8_t *src1, uint32_t src1_stride,
                                       const uint8_t *mask, uint32_t mask_stride,
                                       int w, int h) {
    (void)w;
    const __m128i v_maxval_b = _mm_set1_epi8(AOM_BLEND_A64_MAX_ALPHA);
    const __m128i _r = _mm_set1_epi16(1 << (15 - AOM_BLEND_A64_ROUND_BITS));
    do {
      const __m128i v_m0_b = xx_loadl_64(mask);
      const __m128i v_m1_b = _mm_sub_epi8(v_maxval_b, v_m0_b);
      const __m128i v_res_b = blend_8_u8(src0, src1, &v_m0_b, &v_m1_b, &_r);
      xx_storel_64(dst, v_res_b);
  
      dst += dst_stride;
      src0 += src0_stride;
      src1 += src1_stride;
      mask += mask_stride;
    } while (--h);
  }
  
  static void blend_a64_mask_w16n_sse4_1(
      uint8_t *dst, uint32_t dst_stride, const uint8_t *src0,
      uint32_t src0_stride, const uint8_t *src1, uint32_t src1_stride,
      const uint8_t *mask, uint32_t mask_stride, int w, int h) {
    const __m128i v_maxval_b = _mm_set1_epi8(AOM_BLEND_A64_MAX_ALPHA);
    const __m128i _r = _mm_set1_epi16(1 << (15 - AOM_BLEND_A64_ROUND_BITS));
  
    do {
      int c;
      for (c = 0; c < w; c += 16) {
        const __m128i v_m0_b = xx_loadu_128(mask + c);
        const __m128i v_m1_b = _mm_sub_epi8(v_maxval_b, v_m0_b);
  
        const __m128i v_res_b =
            blend_16_u8(src0 + c, src1 + c, &v_m0_b, &v_m1_b, &_r);
  
        xx_storeu_128(dst + c, v_res_b);
      }
      dst += dst_stride;
      src0 += src0_stride;
      src1 += src1_stride;
      mask += mask_stride;
    } while (--h);
  }
  
  //////////////////////////////////////////////////////////////////////////////
  // Horizontal sub-sampling
  //////////////////////////////////////////////////////////////////////////////
  
  static void blend_a64_mask_sx_w4_sse4_1(
      uint8_t *dst, uint32_t dst_stride, const uint8_t *src0,
      uint32_t src0_stride, const uint8_t *src1, uint32_t src1_stride,
      const uint8_t *mask, uint32_t mask_stride, int w, int h) {
    (void)w;
  
    const __m128i v_shuffle_b = xx_loadu_128(g_blend_a64_mask_shuffle);
    const __m128i v_maxval_b = _mm_set1_epi8(AOM_BLEND_A64_MAX_ALPHA);
    const __m128i _r = _mm_set1_epi16(1 << (15 - AOM_BLEND_A64_ROUND_BITS));
    do {
      const __m128i v_r_b = xx_loadl_64(mask);
      const __m128i v_r0_s_b = _mm_shuffle_epi8(v_r_b, v_shuffle_b);
      const __m128i v_r_lo_b = _mm_unpacklo_epi64(v_r0_s_b, v_r0_s_b);
      const __m128i v_r_hi_b = _mm_unpackhi_epi64(v_r0_s_b, v_r0_s_b);
      const __m128i v_m0_b = _mm_avg_epu8(v_r_lo_b, v_r_hi_b);
      const __m128i v_m1_b = _mm_sub_epi8(v_maxval_b, v_m0_b);
  
      const __m128i v_res_b = blend_4_u8(src0, src1, &v_m0_b, &v_m1_b, &_r);
      xx_storel_32(dst, v_res_b);
  
      dst += dst_stride;
      src0 += src0_stride;
      src1 += src1_stride;
      mask += mask_stride;
    } while (--h);
  }
  
  static void blend_a64_mask_sx_w8_sse4_1(
      uint8_t *dst, uint32_t dst_stride, const uint8_t *src0,
      uint32_t src0_stride, const uint8_t *src1, uint32_t src1_stride,
      const uint8_t *mask, uint32_t mask_stride, int w, int h) {
    (void)w;
  
    const __m128i v_shuffle_b = xx_loadu_128(g_blend_a64_mask_shuffle);
    const __m128i v_maxval_b = _mm_set1_epi8(AOM_BLEND_A64_MAX_ALPHA);
    const __m128i _r = _mm_set1_epi16(1 << (15 - AOM_BLEND_A64_ROUND_BITS));
    do {
      const __m128i v_r_b = xx_loadu_128(mask);
      const __m128i v_r0_s_b = _mm_shuffle_epi8(v_r_b, v_shuffle_b);
      const __m128i v_r_lo_b = _mm_unpacklo_epi64(v_r0_s_b, v_r0_s_b);
      const __m128i v_r_hi_b = _mm_unpackhi_epi64(v_r0_s_b, v_r0_s_b);
      const __m128i v_m0_b = _mm_avg_epu8(v_r_lo_b, v_r_hi_b);
      const __m128i v_m1_b = _mm_sub_epi8(v_maxval_b, v_m0_b);
  
      const __m128i v_res_b = blend_8_u8(src0, src1, &v_m0_b, &v_m1_b, &_r);
  
      xx_storel_64(dst, v_res_b);
  
      dst += dst_stride;
      src0 += src0_stride;
      src1 += src1_stride;
      mask += mask_stride;
    } while (--h);
  }
  
  static void blend_a64_mask_sx_w16n_sse4_1(
      uint8_t *dst, uint32_t dst_stride, const uint8_t *src0,
      uint32_t src0_stride, const uint8_t *src1, uint32_t src1_stride,
      const uint8_t *mask, uint32_t mask_stride, int w, int h) {
    const __m128i v_shuffle_b = xx_loadu_128(g_blend_a64_mask_shuffle);
    const __m128i v_maxval_b = _mm_set1_epi8(AOM_BLEND_A64_MAX_ALPHA);
    const __m128i _r = _mm_set1_epi16(1 << (15 - AOM_BLEND_A64_ROUND_BITS));
  
    do {
      int c;
      for (c = 0; c < w; c += 16) {
        const __m128i v_r0_b = xx_loadu_128(mask + 2 * c);
        const __m128i v_r1_b = xx_loadu_128(mask + 2 * c + 16);
        const __m128i v_r0_s_b = _mm_shuffle_epi8(v_r0_b, v_shuffle_b);
        const __m128i v_r1_s_b = _mm_shuffle_epi8(v_r1_b, v_shuffle_b);
        const __m128i v_r_lo_b = _mm_unpacklo_epi64(v_r0_s_b, v_r1_s_b);
        const __m128i v_r_hi_b = _mm_unpackhi_epi64(v_r0_s_b, v_r1_s_b);
        const __m128i v_m0_b = _mm_avg_epu8(v_r_lo_b, v_r_hi_b);
        const __m128i v_m1_b = _mm_sub_epi8(v_maxval_b, v_m0_b);
  
        const __m128i v_res_b =
            blend_16_u8(src0 + c, src1 + c, &v_m0_b, &v_m1_b, &_r);
  
        xx_storeu_128(dst + c, v_res_b);
      }
      dst += dst_stride;
      src0 += src0_stride;
      src1 += src1_stride;
      mask += mask_stride;
    } while (--h);
  }
  
  //////////////////////////////////////////////////////////////////////////////
  // Vertical sub-sampling
  //////////////////////////////////////////////////////////////////////////////
  
  static void blend_a64_mask_sy_w4_sse4_1(
      uint8_t *dst, uint32_t dst_stride, const uint8_t *src0,
      uint32_t src0_stride, const uint8_t *src1, uint32_t src1_stride,
      const uint8_t *mask, uint32_t mask_stride, int w, int h) {
    (void)w;
  
    const __m128i v_maxval_b = _mm_set1_epi8(AOM_BLEND_A64_MAX_ALPHA);
    const __m128i _r = _mm_set1_epi16(1 << (15 - AOM_BLEND_A64_ROUND_BITS));
  
    do {
      const __m128i v_ra_b = xx_loadl_32(mask);
      const __m128i v_rb_b = xx_loadl_32(mask + mask_stride);
      const __m128i v_m0_b = _mm_avg_epu8(v_ra_b, v_rb_b);
      const __m128i v_m1_b = _mm_sub_epi8(v_maxval_b, v_m0_b);
  
      const __m128i v_res_b = blend_4_u8(src0, src1, &v_m0_b, &v_m1_b, &_r);
  
      xx_storel_32(dst, v_res_b);
  
      dst += dst_stride;
      src0 += src0_stride;
      src1 += src1_stride;
      mask += 2 * mask_stride;
    } while (--h);
  }
  
  static void blend_a64_mask_sy_w8_sse4_1(
      uint8_t *dst, uint32_t dst_stride, const uint8_t *src0,
      uint32_t src0_stride, const uint8_t *src1, uint32_t src1_stride,
      const uint8_t *mask, uint32_t mask_stride, int w, int h) {
    (void)w;
  
    const __m128i v_maxval_b = _mm_set1_epi8(AOM_BLEND_A64_MAX_ALPHA);
    const __m128i _r = _mm_set1_epi16(1 << (15 - AOM_BLEND_A64_ROUND_BITS));
    do {
      const __m128i v_ra_b = xx_loadl_64(mask);
      const __m128i v_rb_b = xx_loadl_64(mask + mask_stride);
      const __m128i v_m0_b = _mm_avg_epu8(v_ra_b, v_rb_b);
      const __m128i v_m1_b = _mm_sub_epi8(v_maxval_b, v_m0_b);
      const __m128i v_res_b = blend_8_u8(src0, src1, &v_m0_b, &v_m1_b, &_r);
  
      xx_storel_64(dst, v_res_b);
  
      dst += dst_stride;
      src0 += src0_stride;
      src1 += src1_stride;
      mask += 2 * mask_stride;
    } while (--h);
  }
  
  static void blend_a64_mask_sy_w16n_sse4_1(
      uint8_t *dst, uint32_t dst_stride, const uint8_t *src0,
      uint32_t src0_stride, const uint8_t *src1, uint32_t src1_stride,
      const uint8_t *mask, uint32_t mask_stride, int w, int h) {
    const __m128i v_maxval_b = _mm_set1_epi8(AOM_BLEND_A64_MAX_ALPHA);
    const __m128i _r = _mm_set1_epi16(1 << (15 - AOM_BLEND_A64_ROUND_BITS));
    do {
      int c;
      for (c = 0; c < w; c += 16) {
        const __m128i v_ra_b = xx_loadu_128(mask + c);
        const __m128i v_rb_b = xx_loadu_128(mask + c + mask_stride);
        const __m128i v_m0_b = _mm_avg_epu8(v_ra_b, v_rb_b);
        const __m128i v_m1_b = _mm_sub_epi8(v_maxval_b, v_m0_b);
  
        const __m128i v_res_b =
            blend_16_u8(src0 + c, src1 + c, &v_m0_b, &v_m1_b, &_r);
  
        xx_storeu_128(dst + c, v_res_b);
      }
      dst += dst_stride;
      src0 += src0_stride;
      src1 += src1_stride;
      mask += 2 * mask_stride;
    } while (--h);
  }
  
  //////////////////////////////////////////////////////////////////////////////
  // Horizontal and Vertical sub-sampling
  //////////////////////////////////////////////////////////////////////////////
  
  static void blend_a64_mask_sx_sy_w4_sse4_1(
      uint8_t *dst, uint32_t dst_stride, const uint8_t *src0,
      uint32_t src0_stride, const uint8_t *src1, uint32_t src1_stride,
      const uint8_t *mask, uint32_t mask_stride, int w, int h) {
    const __m128i v_shuffle_b = xx_loadu_128(g_blend_a64_mask_shuffle);
    const __m128i v_maxval_b = _mm_set1_epi8(AOM_BLEND_A64_MAX_ALPHA);
    const __m128i _r = _mm_set1_epi16(1 << (15 - AOM_BLEND_A64_ROUND_BITS));
    (void)w;
  
    do {
      const __m128i v_ra_b = xx_loadl_64(mask);
      const __m128i v_rb_b = xx_loadl_64(mask + mask_stride);
      const __m128i v_rvs_b = _mm_add_epi8(v_ra_b, v_rb_b);
      const __m128i v_r_s_b = _mm_shuffle_epi8(v_rvs_b, v_shuffle_b);
      const __m128i v_r0_s_w = _mm_cvtepu8_epi16(v_r_s_b);
      const __m128i v_r1_s_w = _mm_cvtepu8_epi16(_mm_srli_si128(v_r_s_b, 8));
      const __m128i v_rs_w = _mm_add_epi16(v_r0_s_w, v_r1_s_w);
      const __m128i v_m0_w = xx_roundn_epu16(v_rs_w, 2);
      const __m128i v_m0_b = _mm_packus_epi16(v_m0_w, v_m0_w);
      const __m128i v_m1_b = _mm_sub_epi8(v_maxval_b, v_m0_b);
  
      const __m128i v_res_b = blend_4_u8(src0, src1, &v_m0_b, &v_m1_b, &_r);
  
      xx_storel_32(dst, v_res_b);
  
      dst += dst_stride;
      src0 += src0_stride;
      src1 += src1_stride;
      mask += 2 * mask_stride;
    } while (--h);
  }
  
  static void blend_a64_mask_sx_sy_w8_sse4_1(
      uint8_t *dst, uint32_t dst_stride, const uint8_t *src0,
      uint32_t src0_stride, const uint8_t *src1, uint32_t src1_stride,
      const uint8_t *mask, uint32_t mask_stride, int w, int h) {
    const __m128i v_shuffle_b = xx_loadu_128(g_blend_a64_mask_shuffle);
    const __m128i v_maxval_b = _mm_set1_epi8(AOM_BLEND_A64_MAX_ALPHA);
    const __m128i _r = _mm_set1_epi16(1 << (15 - AOM_BLEND_A64_ROUND_BITS));
    (void)w;
  
    do {
      const __m128i v_ra_b = xx_loadu_128(mask);
      const __m128i v_rb_b = xx_loadu_128(mask + mask_stride);
  
      const __m128i v_rvs_b = _mm_add_epi8(v_ra_b, v_rb_b);
      const __m128i v_r_s_b = _mm_shuffle_epi8(v_rvs_b, v_shuffle_b);
      const __m128i v_r0_s_w = _mm_cvtepu8_epi16(v_r_s_b);
      const __m128i v_r1_s_w = _mm_cvtepu8_epi16(_mm_srli_si128(v_r_s_b, 8));
      const __m128i v_rs_w = _mm_add_epi16(v_r0_s_w, v_r1_s_w);
      const __m128i v_m0_w = xx_roundn_epu16(v_rs_w, 2);
      const __m128i v_m0_b = _mm_packus_epi16(v_m0_w, v_m0_w);
      const __m128i v_m1_b = _mm_sub_epi8(v_maxval_b, v_m0_b);
  
      const __m128i v_res_b = blend_8_u8(src0, src1, &v_m0_b, &v_m1_b, &_r);
  
      xx_storel_64(dst, v_res_b);
  
      dst += dst_stride;
      src0 += src0_stride;
      src1 += src1_stride;
      mask += 2 * mask_stride;
    } while (--h);
  }
  
  static void blend_a64_mask_sx_sy_w16n_sse4_1(
      uint8_t *dst, uint32_t dst_stride, const uint8_t *src0,
      uint32_t src0_stride, const uint8_t *src1, uint32_t src1_stride,
      const uint8_t *mask, uint32_t mask_stride, int w, int h) {
    const __m128i v_zmask_b = _mm_set_epi8(0, 0xff, 0, 0xff, 0, 0xff, 0, 0xff, 0,
                                           0xff, 0, 0xff, 0, 0xff, 0, 0xff);
    const __m128i v_maxval_b = _mm_set1_epi8(AOM_BLEND_A64_MAX_ALPHA);
    const __m128i _r = _mm_set1_epi16(1 << (15 - AOM_BLEND_A64_ROUND_BITS));
    do {
      int c;
      for (c = 0; c < w; c += 16) {
        const __m128i v_ral_b = xx_loadu_128(mask + 2 * c);
        const __m128i v_rah_b = xx_loadu_128(mask + 2 * c + 16);
        const __m128i v_rbl_b = xx_loadu_128(mask + mask_stride + 2 * c);
        const __m128i v_rbh_b = xx_loadu_128(mask + mask_stride + 2 * c + 16);
        const __m128i v_rvsl_b = _mm_add_epi8(v_ral_b, v_rbl_b);
        const __m128i v_rvsh_b = _mm_add_epi8(v_rah_b, v_rbh_b);
        const __m128i v_rvsal_w = _mm_and_si128(v_rvsl_b, v_zmask_b);
        const __m128i v_rvsah_w = _mm_and_si128(v_rvsh_b, v_zmask_b);
        const __m128i v_rvsbl_w =
            _mm_and_si128(_mm_srli_si128(v_rvsl_b, 1), v_zmask_b);
        const __m128i v_rvsbh_w =
            _mm_and_si128(_mm_srli_si128(v_rvsh_b, 1), v_zmask_b);
        const __m128i v_rsl_w = _mm_add_epi16(v_rvsal_w, v_rvsbl_w);
        const __m128i v_rsh_w = _mm_add_epi16(v_rvsah_w, v_rvsbh_w);
  
        const __m128i v_m0l_w = xx_roundn_epu16(v_rsl_w, 2);
        const __m128i v_m0h_w = xx_roundn_epu16(v_rsh_w, 2);
        const __m128i v_m0_b = _mm_packus_epi16(v_m0l_w, v_m0h_w);
        const __m128i v_m1_b = _mm_sub_epi8(v_maxval_b, v_m0_b);
  
        const __m128i v_res_b =
            blend_16_u8(src0 + c, src1 + c, &v_m0_b, &v_m1_b, &_r);
  
        xx_storeu_128(dst + c, v_res_b);
      }
      dst += dst_stride;
      src0 += src0_stride;
      src1 += src1_stride;
      mask += 2 * mask_stride;
    } while (--h);
  }
  
  //////////////////////////////////////////////////////////////////////////////
  // Dispatch
  //////////////////////////////////////////////////////////////////////////////
  
  void aom_blend_a64_mask_sse4_1(uint8_t *dst, uint32_t dst_stride,
                                 const uint8_t *src0, uint32_t src0_stride,
                                 const uint8_t *src1, uint32_t src1_stride,
                                 const uint8_t *mask, uint32_t mask_stride, int w,
                                 int h, int subx, int suby) {
    typedef void (*blend_fn)(
        uint8_t * dst, uint32_t dst_stride, const uint8_t *src0,
        uint32_t src0_stride, const uint8_t *src1, uint32_t src1_stride,
        const uint8_t *mask, uint32_t mask_stride, int w, int h);
  
    // Dimensions are: width_index X subx X suby
    static const blend_fn blend[3][2][2] = {
      { // w % 16 == 0
        { blend_a64_mask_w16n_sse4_1, blend_a64_mask_sy_w16n_sse4_1 },
        { blend_a64_mask_sx_w16n_sse4_1, blend_a64_mask_sx_sy_w16n_sse4_1 } },
      { // w == 4
        { blend_a64_mask_w4_sse4_1, blend_a64_mask_sy_w4_sse4_1 },
        { blend_a64_mask_sx_w4_sse4_1, blend_a64_mask_sx_sy_w4_sse4_1 } },
      { // w == 8
        { blend_a64_mask_w8_sse4_1, blend_a64_mask_sy_w8_sse4_1 },
        { blend_a64_mask_sx_w8_sse4_1, blend_a64_mask_sx_sy_w8_sse4_1 } }
    };
  
    assert(IMPLIES(src0 == dst, src0_stride == dst_stride));
    assert(IMPLIES(src1 == dst, src1_stride == dst_stride));
  
    assert(h >= 1);
    assert(w >= 1);
    assert(IS_POWER_OF_TWO(h));
    assert(IS_POWER_OF_TWO(w));
  
    if (UNLIKELY((h | w) & 3)) {  // if (w <= 2 || h <= 2)
      aom_blend_a64_mask_c(dst, dst_stride, src0, src0_stride, src1, src1_stride,
                           mask, mask_stride, w, h, subx, suby);
    } else {
      blend[(w >> 2) & 3][subx != 0][suby != 0](dst, dst_stride, src0,
                                                src0_stride, src1, src1_stride,
                                                mask, mask_stride, w, h);
    }
  }
  
  //////////////////////////////////////////////////////////////////////////////
  // No sub-sampling
  //////////////////////////////////////////////////////////////////////////////
  
  static INLINE void blend_a64_mask_bn_w4_sse4_1(
      uint16_t *dst, uint32_t dst_stride, const uint16_t *src0,
      uint32_t src0_stride, const uint16_t *src1, uint32_t src1_stride,
      const uint8_t *mask, uint32_t mask_stride, int h, blend_unit_fn blend) {
    const __m128i v_maxval_w = _mm_set1_epi16(AOM_BLEND_A64_MAX_ALPHA);
  
    do {
      const __m128i v_m0_b = xx_loadl_32(mask);
      const __m128i v_m0_w = _mm_cvtepu8_epi16(v_m0_b);
      const __m128i v_m1_w = _mm_sub_epi16(v_maxval_w, v_m0_w);
  
      const __m128i v_res_w = blend(src0, src1, v_m0_w, v_m1_w);
  
      xx_storel_64(dst, v_res_w);
  
      dst += dst_stride;
      src0 += src0_stride;
      src1 += src1_stride;
      mask += mask_stride;
    } while (--h);
  }
  
  static void blend_a64_mask_b10_w4_sse4_1(
      uint16_t *dst, uint32_t dst_stride, const uint16_t *src0,
      uint32_t src0_stride, const uint16_t *src1, uint32_t src1_stride,
      const uint8_t *mask, uint32_t mask_stride, int w, int h) {
    (void)w;
    blend_a64_mask_bn_w4_sse4_1(dst, dst_stride, src0, src0_stride, src1,
                                src1_stride, mask, mask_stride, h, blend_4_b10);
  }
  
  static void blend_a64_mask_b12_w4_sse4_1(
      uint16_t *dst, uint32_t dst_stride, const uint16_t *src0,
      uint32_t src0_stride, const uint16_t *src1, uint32_t src1_stride,
      const uint8_t *mask, uint32_t mask_stride, int w, int h) {
    (void)w;
    blend_a64_mask_bn_w4_sse4_1(dst, dst_stride, src0, src0_stride, src1,
                                src1_stride, mask, mask_stride, h, blend_4_b12);
  }
  
  static INLINE void blend_a64_mask_bn_w8n_sse4_1(
      uint16_t *dst, uint32_t dst_stride, const uint16_t *src0,
      uint32_t src0_stride, const uint16_t *src1, uint32_t src1_stride,
      const uint8_t *mask, uint32_t mask_stride, int w, int h,
      blend_unit_fn blend) {
    const __m128i v_maxval_w = _mm_set1_epi16(AOM_BLEND_A64_MAX_ALPHA);
  
    do {
      int c;
      for (c = 0; c < w; c += 8) {
        const __m128i v_m0_b = xx_loadl_64(mask + c);
        const __m128i v_m0_w = _mm_cvtepu8_epi16(v_m0_b);
        const __m128i v_m1_w = _mm_sub_epi16(v_maxval_w, v_m0_w);
  
        const __m128i v_res_w = blend(src0 + c, src1 + c, v_m0_w, v_m1_w);
  
        xx_storeu_128(dst + c, v_res_w);
      }
      dst += dst_stride;
      src0 += src0_stride;
      src1 += src1_stride;
      mask += mask_stride;
    } while (--h);
  }
  
  static void blend_a64_mask_b10_w8n_sse4_1(
      uint16_t *dst, uint32_t dst_stride, const uint16_t *src0,
      uint32_t src0_stride, const uint16_t *src1, uint32_t src1_stride,
      const uint8_t *mask, uint32_t mask_stride, int w, int h) {
    blend_a64_mask_bn_w8n_sse4_1(dst, dst_stride, src0, src0_stride, src1,
                                 src1_stride, mask, mask_stride, w, h,
                                 blend_8_b10);
  }
  
  static void blend_a64_mask_b12_w8n_sse4_1(
      uint16_t *dst, uint32_t dst_stride, const uint16_t *src0,
      uint32_t src0_stride, const uint16_t *src1, uint32_t src1_stride,
      const uint8_t *mask, uint32_t mask_stride, int w, int h) {
    blend_a64_mask_bn_w8n_sse4_1(dst, dst_stride, src0, src0_stride, src1,
                                 src1_stride, mask, mask_stride, w, h,
                                 blend_8_b12);
  }
  
  //////////////////////////////////////////////////////////////////////////////
  // Horizontal sub-sampling
  //////////////////////////////////////////////////////////////////////////////
  
  static INLINE void blend_a64_mask_bn_sx_w4_sse4_1(
      uint16_t *dst, uint32_t dst_stride, const uint16_t *src0,
      uint32_t src0_stride, const uint16_t *src1, uint32_t src1_stride,
      const uint8_t *mask, uint32_t mask_stride, int h, blend_unit_fn blend) {
    const __m128i v_zmask_b = _mm_set_epi8(0, 0xff, 0, 0xff, 0, 0xff, 0, 0xff, 0,
                                           0xff, 0, 0xff, 0, 0xff, 0, 0xff);
    const __m128i v_maxval_w = _mm_set1_epi16(AOM_BLEND_A64_MAX_ALPHA);
  
    do {
      const __m128i v_r_b = xx_loadl_64(mask);
      const __m128i v_a_b = _mm_avg_epu8(v_r_b, _mm_srli_si128(v_r_b, 1));
  
      const __m128i v_m0_w = _mm_and_si128(v_a_b, v_zmask_b);
      const __m128i v_m1_w = _mm_sub_epi16(v_maxval_w, v_m0_w);
  
      const __m128i v_res_w = blend(src0, src1, v_m0_w, v_m1_w);
  
      xx_storel_64(dst, v_res_w);
  
      dst += dst_stride;
      src0 += src0_stride;
      src1 += src1_stride;
      mask += mask_stride;
    } while (--h);
  }
  
  static void blend_a64_mask_b10_sx_w4_sse4_1(
      uint16_t *dst, uint32_t dst_stride, const uint16_t *src0,
      uint32_t src0_stride, const uint16_t *src1, uint32_t src1_stride,
      const uint8_t *mask, uint32_t mask_stride, int w, int h) {
    (void)w;
    blend_a64_mask_bn_sx_w4_sse4_1(dst, dst_stride, src0, src0_stride, src1,
                                   src1_stride, mask, mask_stride, h,
                                   blend_4_b10);
  }
  
  static void blend_a64_mask_b12_sx_w4_sse4_1(
      uint16_t *dst, uint32_t dst_stride, const uint16_t *src0,
      uint32_t src0_stride, const uint16_t *src1, uint32_t src1_stride,
      const uint8_t *mask, uint32_t mask_stride, int w, int h) {
    (void)w;
    blend_a64_mask_bn_sx_w4_sse4_1(dst, dst_stride, src0, src0_stride, src1,
                                   src1_stride, mask, mask_stride, h,
                                   blend_4_b12);
  }
  
  static INLINE void blend_a64_mask_bn_sx_w8n_sse4_1(
      uint16_t *dst, uint32_t dst_stride, const uint16_t *src0,
      uint32_t src0_stride, const uint16_t *src1, uint32_t src1_stride,
      const uint8_t *mask, uint32_t mask_stride, int w, int h,
      blend_unit_fn blend) {
    const __m128i v_zmask_b = _mm_set_epi8(0, 0xff, 0, 0xff, 0, 0xff, 0, 0xff, 0,
                                           0xff, 0, 0xff, 0, 0xff, 0, 0xff);
    const __m128i v_maxval_w = _mm_set1_epi16(AOM_BLEND_A64_MAX_ALPHA);
  
    do {
      int c;
      for (c = 0; c < w; c += 8) {
        const __m128i v_r_b = xx_loadu_128(mask + 2 * c);
        const __m128i v_a_b = _mm_avg_epu8(v_r_b, _mm_srli_si128(v_r_b, 1));
  
        const __m128i v_m0_w = _mm_and_si128(v_a_b, v_zmask_b);
        const __m128i v_m1_w = _mm_sub_epi16(v_maxval_w, v_m0_w);
  
        const __m128i v_res_w = blend(src0 + c, src1 + c, v_m0_w, v_m1_w);
  
        xx_storeu_128(dst + c, v_res_w);
      }
      dst += dst_stride;
      src0 += src0_stride;
      src1 += src1_stride;
      mask += mask_stride;
    } while (--h);
  }
  
  static void blend_a64_mask_b10_sx_w8n_sse4_1(
      uint16_t *dst, uint32_t dst_stride, const uint16_t *src0,
      uint32_t src0_stride, const uint16_t *src1, uint32_t src1_stride,
      const uint8_t *mask, uint32_t mask_stride, int w, int h) {
    blend_a64_mask_bn_sx_w8n_sse4_1(dst, dst_stride, src0, src0_stride, src1,
                                    src1_stride, mask, mask_stride, w, h,
                                    blend_8_b10);
  }
  
  static void blend_a64_mask_b12_sx_w8n_sse4_1(
      uint16_t *dst, uint32_t dst_stride, const uint16_t *src0,
      uint32_t src0_stride, const uint16_t *src1, uint32_t src1_stride,
      const uint8_t *mask, uint32_t mask_stride, int w, int h) {
    blend_a64_mask_bn_sx_w8n_sse4_1(dst, dst_stride, src0, src0_stride, src1,
                                    src1_stride, mask, mask_stride, w, h,
                                    blend_8_b12);
  }
  
  //////////////////////////////////////////////////////////////////////////////
  // Vertical sub-sampling
  //////////////////////////////////////////////////////////////////////////////
  
  static INLINE void blend_a64_mask_bn_sy_w4_sse4_1(
      uint16_t *dst, uint32_t dst_stride, const uint16_t *src0,
      uint32_t src0_stride, const uint16_t *src1, uint32_t src1_stride,
      const uint8_t *mask, uint32_t mask_stride, int h, blend_unit_fn blend) {
    const __m128i v_maxval_w = _mm_set1_epi16(AOM_BLEND_A64_MAX_ALPHA);
  
    do {
      const __m128i v_ra_b = xx_loadl_32(mask);
      const __m128i v_rb_b = xx_loadl_32(mask + mask_stride);
      const __m128i v_a_b = _mm_avg_epu8(v_ra_b, v_rb_b);
  
      const __m128i v_m0_w = _mm_cvtepu8_epi16(v_a_b);
      const __m128i v_m1_w = _mm_sub_epi16(v_maxval_w, v_m0_w);
  
      const __m128i v_res_w = blend(src0, src1, v_m0_w, v_m1_w);
  
      xx_storel_64(dst, v_res_w);
  
      dst += dst_stride;
      src0 += src0_stride;
      src1 += src1_stride;
      mask += 2 * mask_stride;
    } while (--h);
  }
  
  static void blend_a64_mask_b10_sy_w4_sse4_1(
      uint16_t *dst, uint32_t dst_stride, const uint16_t *src0,
      uint32_t src0_stride, const uint16_t *src1, uint32_t src1_stride,
      const uint8_t *mask, uint32_t mask_stride, int w, int h) {
    (void)w;
    blend_a64_mask_bn_sy_w4_sse4_1(dst, dst_stride, src0, src0_stride, src1,
                                   src1_stride, mask, mask_stride, h,
                                   blend_4_b10);
  }
  
  static void blend_a64_mask_b12_sy_w4_sse4_1(
      uint16_t *dst, uint32_t dst_stride, const uint16_t *src0,
      uint32_t src0_stride, const uint16_t *src1, uint32_t src1_stride,
      const uint8_t *mask, uint32_t mask_stride, int w, int h) {
    (void)w;
    blend_a64_mask_bn_sy_w4_sse4_1(dst, dst_stride, src0, src0_stride, src1,
                                   src1_stride, mask, mask_stride, h,
                                   blend_4_b12);
  }
  
  static INLINE void blend_a64_mask_bn_sy_w8n_sse4_1(
      uint16_t *dst, uint32_t dst_stride, const uint16_t *src0,
      uint32_t src0_stride, const uint16_t *src1, uint32_t src1_stride,
      const uint8_t *mask, uint32_t mask_stride, int w, int h,
      blend_unit_fn blend) {
    const __m128i v_maxval_w = _mm_set1_epi16(AOM_BLEND_A64_MAX_ALPHA);
  
    do {
      int c;
      for (c = 0; c < w; c += 8) {
        const __m128i v_ra_b = xx_loadl_64(mask + c);
        const __m128i v_rb_b = xx_loadl_64(mask + c + mask_stride);
        const __m128i v_a_b = _mm_avg_epu8(v_ra_b, v_rb_b);
  
        const __m128i v_m0_w = _mm_cvtepu8_epi16(v_a_b);
        const __m128i v_m1_w = _mm_sub_epi16(v_maxval_w, v_m0_w);
  
        const __m128i v_res_w = blend(src0 + c, src1 + c, v_m0_w, v_m1_w);
  
        xx_storeu_128(dst + c, v_res_w);
      }
      dst += dst_stride;
      src0 += src0_stride;
      src1 += src1_stride;
      mask += 2 * mask_stride;
    } while (--h);
  }
  
  static void blend_a64_mask_b10_sy_w8n_sse4_1(
      uint16_t *dst, uint32_t dst_stride, const uint16_t *src0,
      uint32_t src0_stride, const uint16_t *src1, uint32_t src1_stride,
      const uint8_t *mask, uint32_t mask_stride, int w, int h) {
    blend_a64_mask_bn_sy_w8n_sse4_1(dst, dst_stride, src0, src0_stride, src1,
                                    src1_stride, mask, mask_stride, w, h,
                                    blend_8_b10);
  }
  
  static void blend_a64_mask_b12_sy_w8n_sse4_1(
      uint16_t *dst, uint32_t dst_stride, const uint16_t *src0,
      uint32_t src0_stride, const uint16_t *src1, uint32_t src1_stride,
      const uint8_t *mask, uint32_t mask_stride, int w, int h) {
    blend_a64_mask_bn_sy_w8n_sse4_1(dst, dst_stride, src0, src0_stride, src1,
                                    src1_stride, mask, mask_stride, w, h,
                                    blend_8_b12);
  }
  
  //////////////////////////////////////////////////////////////////////////////
  // Horizontal and Vertical sub-sampling
  //////////////////////////////////////////////////////////////////////////////
  
  static INLINE void blend_a64_mask_bn_sx_sy_w4_sse4_1(
      uint16_t *dst, uint32_t dst_stride, const uint16_t *src0,
      uint32_t src0_stride, const uint16_t *src1, uint32_t src1_stride,
      const uint8_t *mask, uint32_t mask_stride, int h, blend_unit_fn blend) {
    const __m128i v_zmask_b = _mm_set_epi8(0, 0xff, 0, 0xff, 0, 0xff, 0, 0xff, 0,
                                           0xff, 0, 0xff, 0, 0xff, 0, 0xff);
    const __m128i v_maxval_w = _mm_set1_epi16(AOM_BLEND_A64_MAX_ALPHA);
  
    do {
      const __m128i v_ra_b = xx_loadl_64(mask);
      const __m128i v_rb_b = xx_loadl_64(mask + mask_stride);
      const __m128i v_rvs_b = _mm_add_epi8(v_ra_b, v_rb_b);
      const __m128i v_rvsa_w = _mm_and_si128(v_rvs_b, v_zmask_b);
      const __m128i v_rvsb_w =
          _mm_and_si128(_mm_srli_si128(v_rvs_b, 1), v_zmask_b);
      const __m128i v_rs_w = _mm_add_epi16(v_rvsa_w, v_rvsb_w);
  
      const __m128i v_m0_w = xx_roundn_epu16(v_rs_w, 2);
      const __m128i v_m1_w = _mm_sub_epi16(v_maxval_w, v_m0_w);
  
      const __m128i v_res_w = blend(src0, src1, v_m0_w, v_m1_w);
  
      xx_storel_64(dst, v_res_w);
  
      dst += dst_stride;
      src0 += src0_stride;
      src1 += src1_stride;
      mask += 2 * mask_stride;
    } while (--h);
  }
  
  static void blend_a64_mask_b10_sx_sy_w4_sse4_1(
      uint16_t *dst, uint32_t dst_stride, const uint16_t *src0,
      uint32_t src0_stride, const uint16_t *src1, uint32_t src1_stride,
      const uint8_t *mask, uint32_t mask_stride, int w, int h) {
    (void)w;
    blend_a64_mask_bn_sx_sy_w4_sse4_1(dst, dst_stride, src0, src0_stride, src1,
                                      src1_stride, mask, mask_stride, h,
                                      blend_4_b10);
  }
  
  static void blend_a64_mask_b12_sx_sy_w4_sse4_1(
      uint16_t *dst, uint32_t dst_stride, const uint16_t *src0,
      uint32_t src0_stride, const uint16_t *src1, uint32_t src1_stride,
      const uint8_t *mask, uint32_t mask_stride, int w, int h) {
    (void)w;
    blend_a64_mask_bn_sx_sy_w4_sse4_1(dst, dst_stride, src0, src0_stride, src1,
                                      src1_stride, mask, mask_stride, h,
                                      blend_4_b12);
  }
  
  static INLINE void blend_a64_mask_bn_sx_sy_w8n_sse4_1(
      uint16_t *dst, uint32_t dst_stride, const uint16_t *src0,
      uint32_t src0_stride, const uint16_t *src1, uint32_t src1_stride,
      const uint8_t *mask, uint32_t mask_stride, int w, int h,
      blend_unit_fn blend) {
    const __m128i v_zmask_b = _mm_set_epi8(0, 0xff, 0, 0xff, 0, 0xff, 0, 0xff, 0,
                                           0xff, 0, 0xff, 0, 0xff, 0, 0xff);
    const __m128i v_maxval_w = _mm_set1_epi16(AOM_BLEND_A64_MAX_ALPHA);
  
    do {
      int c;
      for (c = 0; c < w; c += 8) {
        const __m128i v_ra_b = xx_loadu_128(mask + 2 * c);
        const __m128i v_rb_b = xx_loadu_128(mask + 2 * c + mask_stride);
        const __m128i v_rvs_b = _mm_add_epi8(v_ra_b, v_rb_b);
        const __m128i v_rvsa_w = _mm_and_si128(v_rvs_b, v_zmask_b);
        const __m128i v_rvsb_w =
            _mm_and_si128(_mm_srli_si128(v_rvs_b, 1), v_zmask_b);
        const __m128i v_rs_w = _mm_add_epi16(v_rvsa_w, v_rvsb_w);
  
        const __m128i v_m0_w = xx_roundn_epu16(v_rs_w, 2);
        const __m128i v_m1_w = _mm_sub_epi16(v_maxval_w, v_m0_w);
  
        const __m128i v_res_w = blend(src0 + c, src1 + c, v_m0_w, v_m1_w);
  
        xx_storeu_128(dst + c, v_res_w);
      }
      dst += dst_stride;
      src0 += src0_stride;
      src1 += src1_stride;
      mask += 2 * mask_stride;
    } while (--h);
  }
  
  static void blend_a64_mask_b10_sx_sy_w8n_sse4_1(
      uint16_t *dst, uint32_t dst_stride, const uint16_t *src0,
      uint32_t src0_stride, const uint16_t *src1, uint32_t src1_stride,
      const uint8_t *mask, uint32_t mask_stride, int w, int h) {
    blend_a64_mask_bn_sx_sy_w8n_sse4_1(dst, dst_stride, src0, src0_stride, src1,
                                       src1_stride, mask, mask_stride, w, h,
                                       blend_8_b10);
  }
  
  static void blend_a64_mask_b12_sx_sy_w8n_sse4_1(
      uint16_t *dst, uint32_t dst_stride, const uint16_t *src0,
      uint32_t src0_stride, const uint16_t *src1, uint32_t src1_stride,
      const uint8_t *mask, uint32_t mask_stride, int w, int h) {
    blend_a64_mask_bn_sx_sy_w8n_sse4_1(dst, dst_stride, src0, src0_stride, src1,
                                       src1_stride, mask, mask_stride, w, h,
                                       blend_8_b12);
  }
  
  //////////////////////////////////////////////////////////////////////////////
  // Dispatch
  //////////////////////////////////////////////////////////////////////////////
  
  void aom_highbd_blend_a64_mask_sse4_1(uint8_t *dst_8, uint32_t dst_stride,
                                        const uint8_t *src0_8,
                                        uint32_t src0_stride,
                                        const uint8_t *src1_8,
                                        uint32_t src1_stride, const uint8_t *mask,
                                        uint32_t mask_stride, int w, int h,
                                        int subx, int suby, int bd) {
    typedef void (*blend_fn)(
        uint16_t * dst, uint32_t dst_stride, const uint16_t *src0,
        uint32_t src0_stride, const uint16_t *src1, uint32_t src1_stride,
        const uint8_t *mask, uint32_t mask_stride, int w, int h);
  
    // Dimensions are: bd_index X width_index X subx X suby
    static const blend_fn blend[2][2][2][2] = {
      {   // bd == 8 or 10
        { // w % 8 == 0
          { blend_a64_mask_b10_w8n_sse4_1, blend_a64_mask_b10_sy_w8n_sse4_1 },
          { blend_a64_mask_b10_sx_w8n_sse4_1,
            blend_a64_mask_b10_sx_sy_w8n_sse4_1 } },
        { // w == 4
          { blend_a64_mask_b10_w4_sse4_1, blend_a64_mask_b10_sy_w4_sse4_1 },
          { blend_a64_mask_b10_sx_w4_sse4_1,
            blend_a64_mask_b10_sx_sy_w4_sse4_1 } } },
      {   // bd == 12
        { // w % 8 == 0
          { blend_a64_mask_b12_w8n_sse4_1, blend_a64_mask_b12_sy_w8n_sse4_1 },
          { blend_a64_mask_b12_sx_w8n_sse4_1,
            blend_a64_mask_b12_sx_sy_w8n_sse4_1 } },
        { // w == 4
          { blend_a64_mask_b12_w4_sse4_1, blend_a64_mask_b12_sy_w4_sse4_1 },
          { blend_a64_mask_b12_sx_w4_sse4_1,
            blend_a64_mask_b12_sx_sy_w4_sse4_1 } } }
    };
  
    assert(IMPLIES(src0_8 == dst_8, src0_stride == dst_stride));
    assert(IMPLIES(src1_8 == dst_8, src1_stride == dst_stride));
  
    assert(h >= 1);
    assert(w >= 1);
    assert(IS_POWER_OF_TWO(h));
    assert(IS_POWER_OF_TWO(w));
  
    assert(bd == 8 || bd == 10 || bd == 12);
    if (UNLIKELY((h | w) & 3)) {  // if (w <= 2 || h <= 2)
      aom_highbd_blend_a64_mask_c(dst_8, dst_stride, src0_8, src0_stride, src1_8,
                                  src1_stride, mask, mask_stride, w, h, subx,
                                  suby, bd);
    } else {
      uint16_t *const dst = CONVERT_TO_SHORTPTR(dst_8);
      const uint16_t *const src0 = CONVERT_TO_SHORTPTR(src0_8);
      const uint16_t *const src1 = CONVERT_TO_SHORTPTR(src1_8);
  
      blend[bd == 12][(w >> 2) & 1][subx != 0][suby != 0](
          dst, dst_stride, src0, src0_stride, src1, src1_stride, mask,
          mask_stride, w, h);
    }
  }
  
  static INLINE void blend_a64_d16_mask_w16_sse41(
      uint8_t *dst, const CONV_BUF_TYPE *src0, const CONV_BUF_TYPE *src1,
      const __m128i *m0, const __m128i *m1, const __m128i *v_round_offset,
      const __m128i *v_maxval, int shift) {
    const __m128i max_minus_m0 = _mm_sub_epi16(*v_maxval, *m0);
    const __m128i max_minus_m1 = _mm_sub_epi16(*v_maxval, *m1);
    const __m128i s0_0 = xx_loadu_128(src0);
    const __m128i s0_1 = xx_loadu_128(src0 + 8);
    const __m128i s1_0 = xx_loadu_128(src1);
    const __m128i s1_1 = xx_loadu_128(src1 + 8);
    __m128i res0_lo = _mm_madd_epi16(_mm_unpacklo_epi16(s0_0, s1_0),
                                     _mm_unpacklo_epi16(*m0, max_minus_m0));
    __m128i res0_hi = _mm_madd_epi16(_mm_unpackhi_epi16(s0_0, s1_0),
                                     _mm_unpackhi_epi16(*m0, max_minus_m0));
    __m128i res1_lo = _mm_madd_epi16(_mm_unpacklo_epi16(s0_1, s1_1),
                                     _mm_unpacklo_epi16(*m1, max_minus_m1));
    __m128i res1_hi = _mm_madd_epi16(_mm_unpackhi_epi16(s0_1, s1_1),
                                     _mm_unpackhi_epi16(*m1, max_minus_m1));
    res0_lo = _mm_srai_epi32(_mm_sub_epi32(res0_lo, *v_round_offset), shift);
    res0_hi = _mm_srai_epi32(_mm_sub_epi32(res0_hi, *v_round_offset), shift);
    res1_lo = _mm_srai_epi32(_mm_sub_epi32(res1_lo, *v_round_offset), shift);
    res1_hi = _mm_srai_epi32(_mm_sub_epi32(res1_hi, *v_round_offset), shift);
    const __m128i res0 = _mm_packs_epi32(res0_lo, res0_hi);
    const __m128i res1 = _mm_packs_epi32(res1_lo, res1_hi);
    const __m128i res = _mm_packus_epi16(res0, res1);
  
    _mm_storeu_si128((__m128i *)(dst), res);
  }
  
  static INLINE void lowbd_blend_a64_d16_mask_subw0_subh0_w16_sse4_1(
      uint8_t *dst, uint32_t dst_stride, const CONV_BUF_TYPE *src0,
      uint32_t src0_stride, const CONV_BUF_TYPE *src1, uint32_t src1_stride,
      const uint8_t *mask, uint32_t mask_stride, int h, int w,
      const __m128i *round_offset, int shift) {
    const __m128i v_maxval = _mm_set1_epi16(AOM_BLEND_A64_MAX_ALPHA);
    for (int i = 0; i < h; ++i) {
      for (int j = 0; j < w; j += 16) {
        const __m128i m = xx_loadu_128(mask + j);
        const __m128i m0 = _mm_cvtepu8_epi16(m);
        const __m128i m1 = _mm_cvtepu8_epi16(_mm_srli_si128(m, 8));
  
        blend_a64_d16_mask_w16_sse41(dst + j, src0 + j, src1 + j, &m0, &m1,
                                     round_offset, &v_maxval, shift);
      }
      mask += mask_stride;
      dst += dst_stride;
      src0 += src0_stride;
      src1 += src1_stride;
    }
  }
  
  static INLINE void lowbd_blend_a64_d16_mask_subw1_subh1_w16_sse4_1(
      uint8_t *dst, uint32_t dst_stride, const CONV_BUF_TYPE *src0,
      uint32_t src0_stride, const CONV_BUF_TYPE *src1, uint32_t src1_stride,
      const uint8_t *mask, uint32_t mask_stride, int h, int w,
      const __m128i *round_offset, int shift) {
    const __m128i v_maxval = _mm_set1_epi16(AOM_BLEND_A64_MAX_ALPHA);
    const __m128i one_b = _mm_set1_epi8(1);
    const __m128i two_w = _mm_set1_epi16(2);
    for (int i = 0; i < h; ++i) {
      for (int j = 0; j < w; j += 16) {
        const __m128i m_i00 = xx_loadu_128(mask + 2 * j);
        const __m128i m_i01 = xx_loadu_128(mask + 2 * j + 16);
        const __m128i m_i10 = xx_loadu_128(mask + mask_stride + 2 * j);
        const __m128i m_i11 = xx_loadu_128(mask + mask_stride + 2 * j + 16);
  
        const __m128i m0_ac = _mm_adds_epu8(m_i00, m_i10);
        const __m128i m1_ac = _mm_adds_epu8(m_i01, m_i11);
        const __m128i m0_acbd = _mm_maddubs_epi16(m0_ac, one_b);
        const __m128i m1_acbd = _mm_maddubs_epi16(m1_ac, one_b);
        const __m128i m0 = _mm_srli_epi16(_mm_add_epi16(m0_acbd, two_w), 2);
        const __m128i m1 = _mm_srli_epi16(_mm_add_epi16(m1_acbd, two_w), 2);
  
        blend_a64_d16_mask_w16_sse41(dst + j, src0 + j, src1 + j, &m0, &m1,
                                     round_offset, &v_maxval, shift);
      }
      mask += mask_stride << 1;
      dst += dst_stride;
      src0 += src0_stride;
      src1 += src1_stride;
    }
  }
  
  static INLINE void lowbd_blend_a64_d16_mask_subw1_subh0_w16_sse4_1(
      uint8_t *dst, uint32_t dst_stride, const CONV_BUF_TYPE *src0,
      uint32_t src0_stride, const CONV_BUF_TYPE *src1, uint32_t src1_stride,
      const uint8_t *mask, uint32_t mask_stride, int h, int w,
      const __m128i *round_offset, int shift) {
    const __m128i v_maxval = _mm_set1_epi16(AOM_BLEND_A64_MAX_ALPHA);
    const __m128i one_b = _mm_set1_epi8(1);
    const __m128i zeros = _mm_setzero_si128();
    for (int i = 0; i < h; ++i) {
      for (int j = 0; j < w; j += 16) {
        const __m128i m_i00 = xx_loadu_128(mask + 2 * j);
        const __m128i m_i01 = xx_loadu_128(mask + 2 * j + 16);
        const __m128i m0_ac = _mm_maddubs_epi16(m_i00, one_b);
        const __m128i m1_ac = _mm_maddubs_epi16(m_i01, one_b);
        const __m128i m0 = _mm_avg_epu16(m0_ac, zeros);
        const __m128i m1 = _mm_avg_epu16(m1_ac, zeros);
  
        blend_a64_d16_mask_w16_sse41(dst + j, src0 + j, src1 + j, &m0, &m1,
                                     round_offset, &v_maxval, shift);
      }
      mask += mask_stride;
      dst += dst_stride;
      src0 += src0_stride;
      src1 += src1_stride;
    }
  }
  
  static INLINE void lowbd_blend_a64_d16_mask_subw0_subh1_w16_sse4_1(
      uint8_t *dst, uint32_t dst_stride, const CONV_BUF_TYPE *src0,
      uint32_t src0_stride, const CONV_BUF_TYPE *src1, uint32_t src1_stride,
      const uint8_t *mask, uint32_t mask_stride, int h, int w,
      const __m128i *round_offset, int shift) {
    const __m128i v_maxval = _mm_set1_epi16(AOM_BLEND_A64_MAX_ALPHA);
    const __m128i zeros = _mm_setzero_si128();
    for (int i = 0; i < h; ++i) {
      for (int j = 0; j < w; j += 16) {
        const __m128i m_i00 = xx_loadu_128(mask + j);
        const __m128i m_i10 = xx_loadu_128(mask + mask_stride + j);
  
        const __m128i m_ac = _mm_avg_epu8(_mm_adds_epu8(m_i00, m_i10), zeros);
        const __m128i m0 = _mm_cvtepu8_epi16(m_ac);
        const __m128i m1 = _mm_cvtepu8_epi16(_mm_srli_si128(m_ac, 8));
  
        blend_a64_d16_mask_w16_sse41(dst + j, src0 + j, src1 + j, &m0, &m1,
                                     round_offset, &v_maxval, shift);
      }
      mask += mask_stride << 1;
      dst += dst_stride;
      src0 += src0_stride;
      src1 += src1_stride;
    }
  }
  
  void aom_lowbd_blend_a64_d16_mask_sse4_1(
      uint8_t *dst, uint32_t dst_stride, const CONV_BUF_TYPE *src0,
      uint32_t src0_stride, const CONV_BUF_TYPE *src1, uint32_t src1_stride,
      const uint8_t *mask, uint32_t mask_stride, int w, int h, int subw, int subh,
      ConvolveParams *conv_params) {
    const int bd = 8;
    const int round_bits =
        2 * FILTER_BITS - conv_params->round_0 - conv_params->round_1;
  
    const int round_offset =
        ((1 << (round_bits + bd)) + (1 << (round_bits + bd - 1)) -
         (1 << (round_bits - 1)))
        << AOM_BLEND_A64_ROUND_BITS;
  
    const int shift = round_bits + AOM_BLEND_A64_ROUND_BITS;
    assert(IMPLIES((void *)src0 == dst, src0_stride == dst_stride));
    assert(IMPLIES((void *)src1 == dst, src1_stride == dst_stride));
  
    assert(h >= 4);
    assert(w >= 4);
    assert(IS_POWER_OF_TWO(h));
    assert(IS_POWER_OF_TWO(w));
  
    const __m128i v_round_offset = _mm_set1_epi32(round_offset);
  
    if (subw == 0 && subh == 0) {
      switch (w) {
        case 4:
          aom_lowbd_blend_a64_d16_mask_subw0_subh0_w4_sse4_1(
              dst, dst_stride, src0, src0_stride, src1, src1_stride, mask,
              mask_stride, h, &v_round_offset, shift);
          break;
        case 8:
          aom_lowbd_blend_a64_d16_mask_subw0_subh0_w8_sse4_1(
              dst, dst_stride, src0, src0_stride, src1, src1_stride, mask,
              mask_stride, h, &v_round_offset, shift);
          break;
        default:
          lowbd_blend_a64_d16_mask_subw0_subh0_w16_sse4_1(
              dst, dst_stride, src0, src0_stride, src1, src1_stride, mask,
              mask_stride, h, w, &v_round_offset, shift);
          break;
      }
  
    } else if (subw == 1 && subh == 1) {
      switch (w) {
        case 4:
          aom_lowbd_blend_a64_d16_mask_subw1_subh1_w4_sse4_1(
              dst, dst_stride, src0, src0_stride, src1, src1_stride, mask,
              mask_stride, h, &v_round_offset, shift);
          break;
        case 8:
          aom_lowbd_blend_a64_d16_mask_subw1_subh1_w8_sse4_1(
              dst, dst_stride, src0, src0_stride, src1, src1_stride, mask,
              mask_stride, h, &v_round_offset, shift);
          break;
        default:
          lowbd_blend_a64_d16_mask_subw1_subh1_w16_sse4_1(
              dst, dst_stride, src0, src0_stride, src1, src1_stride, mask,
              mask_stride, h, w, &v_round_offset, shift);
          break;
      }
    } else if (subw == 1 && subh == 0) {
      switch (w) {
        case 4:
          aom_lowbd_blend_a64_d16_mask_subw1_subh0_w4_sse4_1(
              dst, dst_stride, src0, src0_stride, src1, src1_stride, mask,
              mask_stride, h, &v_round_offset, shift);
          break;
        case 8:
          aom_lowbd_blend_a64_d16_mask_subw1_subh0_w8_sse4_1(
              dst, dst_stride, src0, src0_stride, src1, src1_stride, mask,
              mask_stride, h, &v_round_offset, shift);
          break;
        default:
          lowbd_blend_a64_d16_mask_subw1_subh0_w16_sse4_1(
              dst, dst_stride, src0, src0_stride, src1, src1_stride, mask,
              mask_stride, h, w, &v_round_offset, shift);
          break;
      }
    } else {
      switch (w) {
        case 4:
          aom_lowbd_blend_a64_d16_mask_subw0_subh1_w4_sse4_1(
              dst, dst_stride, src0, src0_stride, src1, src1_stride, mask,
              mask_stride, h, &v_round_offset, shift);
          break;
        case 8:
          aom_lowbd_blend_a64_d16_mask_subw0_subh1_w8_sse4_1(
              dst, dst_stride, src0, src0_stride, src1, src1_stride, mask,
              mask_stride, h, &v_round_offset, shift);
          break;
        default:
          lowbd_blend_a64_d16_mask_subw0_subh1_w16_sse4_1(
              dst, dst_stride, src0, src0_stride, src1, src1_stride, mask,
              mask_stride, h, w, &v_round_offset, shift);
          break;
      }
    }
  }
  
  //////////////////////////////////////////////////////////////////////////////
  // aom_highbd_blend_a64_d16_mask_sse4_1()
  //////////////////////////////////////////////////////////////////////////////
  
  static INLINE void highbd_blend_a64_d16_mask_w4_sse4_1(
      uint16_t *dst, int dst_stride, const CONV_BUF_TYPE *src0, int src0_stride,
      const CONV_BUF_TYPE *src1, int src1_stride, const __m128i *mask0a,
      const __m128i *mask0b, const __m128i *round_offset, int shift,
      const __m128i *clip_low, const __m128i *clip_high,
      const __m128i *mask_max) {
    // Load 4 pixels from each of 4 rows from each source
    const __m128i s0a =
        _mm_set_epi64x(*(uint64_t *)src0, *(uint64_t *)(src0 + src0_stride));
    const __m128i s0b = _mm_set_epi64x(*(uint64_t *)(src0 + 2 * src0_stride),
                                       *(uint64_t *)(src0 + 3 * src0_stride));
    const __m128i s1a =
        _mm_set_epi64x(*(uint64_t *)(src1), *(uint64_t *)(src1 + src1_stride));
    const __m128i s1b = _mm_set_epi64x(*(uint64_t *)(src1 + 2 * src1_stride),
                                       *(uint64_t *)(src1 + 3 * src1_stride));
  
    // Generate the inverse masks
    const __m128i mask1a = _mm_sub_epi16(*mask_max, *mask0a);
    const __m128i mask1b = _mm_sub_epi16(*mask_max, *mask0b);
  
    // Multiply each mask by the respective source
    const __m128i mul0a_highs = _mm_mulhi_epu16(*mask0a, s0a);
    const __m128i mul0a_lows = _mm_mullo_epi16(*mask0a, s0a);
    const __m128i mul0ah = _mm_unpackhi_epi16(mul0a_lows, mul0a_highs);
    const __m128i mul0al = _mm_unpacklo_epi16(mul0a_lows, mul0a_highs);
    const __m128i mul1a_highs = _mm_mulhi_epu16(mask1a, s1a);
    const __m128i mul1a_lows = _mm_mullo_epi16(mask1a, s1a);
    const __m128i mul1ah = _mm_unpackhi_epi16(mul1a_lows, mul1a_highs);
    const __m128i mul1al = _mm_unpacklo_epi16(mul1a_lows, mul1a_highs);
  
    const __m128i mul0b_highs = _mm_mulhi_epu16(*mask0b, s0b);
    const __m128i mul0b_lows = _mm_mullo_epi16(*mask0b, s0b);
    const __m128i mul0bh = _mm_unpackhi_epi16(mul0b_lows, mul0b_highs);
    const __m128i mul0bl = _mm_unpacklo_epi16(mul0b_lows, mul0b_highs);
    const __m128i mul1b_highs = _mm_mulhi_epu16(mask1b, s1b);
    const __m128i mul1b_lows = _mm_mullo_epi16(mask1b, s1b);
    const __m128i mul1bh = _mm_unpackhi_epi16(mul1b_lows, mul1b_highs);
    const __m128i mul1bl = _mm_unpacklo_epi16(mul1b_lows, mul1b_highs);
  
    const __m128i sumah = _mm_add_epi32(mul0ah, mul1ah);
    const __m128i sumal = _mm_add_epi32(mul0al, mul1al);
    const __m128i sumbh = _mm_add_epi32(mul0bh, mul1bh);
    const __m128i sumbl = _mm_add_epi32(mul0bl, mul1bl);
  
    const __m128i roundah =
        _mm_srai_epi32(_mm_sub_epi32(sumah, *round_offset), shift);
    const __m128i roundbh =
        _mm_srai_epi32(_mm_sub_epi32(sumbh, *round_offset), shift);
    const __m128i roundal =
        _mm_srai_epi32(_mm_sub_epi32(sumal, *round_offset), shift);
    const __m128i roundbl =
        _mm_srai_epi32(_mm_sub_epi32(sumbl, *round_offset), shift);
  
    const __m128i packa = _mm_packs_epi32(roundal, roundah);
    const __m128i packb = _mm_packs_epi32(roundbl, roundbh);
  
    const __m128i clipa =
        _mm_min_epi16(_mm_max_epi16(packa, *clip_low), *clip_high);
    const __m128i clipb =
        _mm_min_epi16(_mm_max_epi16(packb, *clip_low), *clip_high);
  
    xx_storel_64(dst, _mm_srli_si128(clipa, 8));
    xx_storel_64(dst + dst_stride, clipa);
    xx_storel_64(dst + 2 * dst_stride, _mm_srli_si128(clipb, 8));
    xx_storel_64(dst + 3 * dst_stride, clipb);
  }
  
  static INLINE void highbd_blend_a64_d16_mask_subw0_subh0_w4_sse4_1(
      uint16_t *dst, uint32_t dst_stride, const CONV_BUF_TYPE *src0,
      uint32_t src0_stride, const CONV_BUF_TYPE *src1, uint32_t src1_stride,
      const uint8_t *mask, uint32_t mask_stride, int h,
      const __m128i *round_offset, int shift, const __m128i *clip_low,
      const __m128i *clip_high, const __m128i *mask_max) {
    do {
      const __m128i mask0a8 = _mm_set_epi32(0, 0, *(uint32_t *)mask,
                                            *(uint32_t *)(mask + mask_stride));
      const __m128i mask0b8 =
          _mm_set_epi32(0, 0, *(uint32_t *)(mask + 2 * mask_stride),
                        *(uint32_t *)(mask + 3 * mask_stride));
      const __m128i mask0a = _mm_cvtepu8_epi16(mask0a8);
      const __m128i mask0b = _mm_cvtepu8_epi16(mask0b8);
  
      highbd_blend_a64_d16_mask_w4_sse4_1(
          dst, dst_stride, src0, src0_stride, src1, src1_stride, &mask0a, &mask0b,
          round_offset, shift, clip_low, clip_high, mask_max);
  
      dst += dst_stride * 4;
      src0 += src0_stride * 4;
      src1 += src1_stride * 4;
      mask += mask_stride * 4;
    } while (h -= 4);
  }
  
  static INLINE void highbd_blend_a64_d16_mask_subw1_subh1_w4_sse4_1(
      uint16_t *dst, uint32_t dst_stride, const CONV_BUF_TYPE *src0,
      uint32_t src0_stride, const CONV_BUF_TYPE *src1, uint32_t src1_stride,
      const uint8_t *mask, uint32_t mask_stride, int h,
      const __m128i *round_offset, int shift, const __m128i *clip_low,
      const __m128i *clip_high, const __m128i *mask_max) {
    const __m128i one_b = _mm_set1_epi8(1);
    const __m128i two_w = _mm_set1_epi16(2);
    do {
      // Load 8 pixels from each of 8 rows of mask,
      // (saturating) add together rows then use madd to add adjacent pixels
      // Finally, divide each value by 4 (with rounding)
      const __m128i m02 = _mm_set_epi64x(*(uint64_t *)(mask),
                                         *(uint64_t *)(mask + 2 * mask_stride));
      const __m128i m13 = _mm_set_epi64x(*(uint64_t *)(mask + mask_stride),
                                         *(uint64_t *)(mask + 3 * mask_stride));
      const __m128i m0123 = _mm_maddubs_epi16(_mm_adds_epu8(m02, m13), one_b);
      const __m128i mask_0a = _mm_srli_epi16(_mm_add_epi16(m0123, two_w), 2);
      const __m128i m46 = _mm_set_epi64x(*(uint64_t *)(mask + 4 * mask_stride),
                                         *(uint64_t *)(mask + 6 * mask_stride));
      const __m128i m57 = _mm_set_epi64x(*(uint64_t *)(mask + 5 * mask_stride),
                                         *(uint64_t *)(mask + 7 * mask_stride));
      const __m128i m4567 = _mm_maddubs_epi16(_mm_adds_epu8(m46, m57), one_b);
      const __m128i mask_0b = _mm_srli_epi16(_mm_add_epi16(m4567, two_w), 2);
  
      highbd_blend_a64_d16_mask_w4_sse4_1(
          dst, dst_stride, src0, src0_stride, src1, src1_stride, &mask_0a,
          &mask_0b, round_offset, shift, clip_low, clip_high, mask_max);
  
      dst += dst_stride * 4;
      src0 += src0_stride * 4;
      src1 += src1_stride * 4;
      mask += mask_stride * 8;
    } while (h -= 4);
  }
  
  static INLINE void highbd_blend_a64_d16_mask_w8_sse4_1(
      uint16_t *dst, int dst_stride, const CONV_BUF_TYPE *src0, int src0_stride,
      const CONV_BUF_TYPE *src1, int src1_stride, const __m128i *mask0a,
      const __m128i *mask0b, const __m128i *round_offset, int shift,
      const __m128i *clip_low, const __m128i *clip_high,
      const __m128i *max_mask) {
    // Load 8x pixels from each of 2 rows from each source
    const __m128i s0a = xx_loadu_128(src0);
    const __m128i s0b = xx_loadu_128(src0 + src0_stride);
    const __m128i s1a = xx_loadu_128(src1);
    const __m128i s1b = xx_loadu_128(src1 + src1_stride);
  
    // Generate inverse masks
    const __m128i mask1a = _mm_sub_epi16(*max_mask, *mask0a);
    const __m128i mask1b = _mm_sub_epi16(*max_mask, *mask0b);
  
    // Multiply sources by respective masks
    const __m128i mul0a_highs = _mm_mulhi_epu16(*mask0a, s0a);
    const __m128i mul0a_lows = _mm_mullo_epi16(*mask0a, s0a);
    const __m128i mul0ah = _mm_unpackhi_epi16(mul0a_lows, mul0a_highs);
    const __m128i mul0al = _mm_unpacklo_epi16(mul0a_lows, mul0a_highs);
  
    const __m128i mul1a_highs = _mm_mulhi_epu16(mask1a, s1a);
    const __m128i mul1a_lows = _mm_mullo_epi16(mask1a, s1a);
    const __m128i mul1ah = _mm_unpackhi_epi16(mul1a_lows, mul1a_highs);
    const __m128i mul1al = _mm_unpacklo_epi16(mul1a_lows, mul1a_highs);
  
    const __m128i sumah = _mm_add_epi32(mul0ah, mul1ah);
    const __m128i sumal = _mm_add_epi32(mul0al, mul1al);
  
    const __m128i mul0b_highs = _mm_mulhi_epu16(*mask0b, s0b);
    const __m128i mul0b_lows = _mm_mullo_epi16(*mask0b, s0b);
    const __m128i mul0bh = _mm_unpackhi_epi16(mul0b_lows, mul0b_highs);
    const __m128i mul0bl = _mm_unpacklo_epi16(mul0b_lows, mul0b_highs);
  
    const __m128i mul1b_highs = _mm_mulhi_epu16(mask1b, s1b);
    const __m128i mul1b_lows = _mm_mullo_epi16(mask1b, s1b);
    const __m128i mul1bh = _mm_unpackhi_epi16(mul1b_lows, mul1b_highs);
    const __m128i mul1bl = _mm_unpacklo_epi16(mul1b_lows, mul1b_highs);
  
    const __m128i sumbh = _mm_add_epi32(mul0bh, mul1bh);
    const __m128i sumbl = _mm_add_epi32(mul0bl, mul1bl);
  
    const __m128i roundah =
        _mm_srai_epi32(_mm_sub_epi32(sumah, *round_offset), shift);
    const __m128i roundal =
        _mm_srai_epi32(_mm_sub_epi32(sumal, *round_offset), shift);
    const __m128i roundbh =
        _mm_srai_epi32(_mm_sub_epi32(sumbh, *round_offset), shift);
    const __m128i roundbl =
        _mm_srai_epi32(_mm_sub_epi32(sumbl, *round_offset), shift);
  
    const __m128i packa = _mm_packs_epi32(roundal, roundah);
    const __m128i clipa =
        _mm_min_epi16(_mm_max_epi16(packa, *clip_low), *clip_high);
    const __m128i packb = _mm_packs_epi32(roundbl, roundbh);
    const __m128i clipb =
        _mm_min_epi16(_mm_max_epi16(packb, *clip_low), *clip_high);
  
    xx_storeu_128(dst, clipa);
    xx_storeu_128(dst + dst_stride, clipb);
  }
  
  static INLINE void highbd_blend_a64_d16_mask_subw0_subh0_w8_sse4_1(
      uint16_t *dst, uint32_t dst_stride, const CONV_BUF_TYPE *src0,
      uint32_t src0_stride, const CONV_BUF_TYPE *src1, uint32_t src1_stride,
      const uint8_t *mask, uint32_t mask_stride, int h,
      const __m128i *round_offset, int shift, const __m128i *clip_low,
      const __m128i *clip_high, const __m128i *max_mask) {
    do {
      const __m128i mask0a = _mm_cvtepu8_epi16(xx_loadl_64(mask));
      const __m128i mask0b = _mm_cvtepu8_epi16(xx_loadl_64(mask + mask_stride));
      highbd_blend_a64_d16_mask_w8_sse4_1(
          dst, dst_stride, src0, src0_stride, src1, src1_stride, &mask0a, &mask0b,
          round_offset, shift, clip_low, clip_high, max_mask);
  
      dst += dst_stride * 2;
      src0 += src0_stride * 2;
      src1 += src1_stride * 2;
      mask += mask_stride * 2;
    } while (h -= 2);
  }
  
  static INLINE void highbd_blend_a64_d16_mask_subw1_subh1_w8_sse4_1(
      uint16_t *dst, uint32_t dst_stride, const CONV_BUF_TYPE *src0,
      uint32_t src0_stride, const CONV_BUF_TYPE *src1, uint32_t src1_stride,
      const uint8_t *mask, uint32_t mask_stride, int h,
      const __m128i *round_offset, int shift, const __m128i *clip_low,
      const __m128i *clip_high, const __m128i *max_mask) {
    const __m128i one_b = _mm_set1_epi8(1);
    const __m128i two_w = _mm_set1_epi16(2);
    do {
      const __m128i mask_thisrowa = xx_loadu_128(mask);
      const __m128i mask_nextrowa = xx_loadu_128(mask + mask_stride);
      const __m128i mask_thisrowb = xx_loadu_128(mask + 2 * mask_stride);
      const __m128i mask_nextrowb = xx_loadu_128(mask + 3 * mask_stride);
      const __m128i mask_bothrowsa = _mm_adds_epu8(mask_thisrowa, mask_nextrowa);
      const __m128i mask_bothrowsb = _mm_adds_epu8(mask_thisrowb, mask_nextrowb);
      const __m128i mask_16a = _mm_maddubs_epi16(mask_bothrowsa, one_b);
      const __m128i mask_16b = _mm_maddubs_epi16(mask_bothrowsb, one_b);
      const __m128i mask_sa = _mm_srli_epi16(_mm_add_epi16(mask_16a, two_w), 2);
      const __m128i mask_sb = _mm_srli_epi16(_mm_add_epi16(mask_16b, two_w), 2);
  
      highbd_blend_a64_d16_mask_w8_sse4_1(
          dst, dst_stride, src0, src0_stride, src1, src1_stride, &mask_sa,
          &mask_sb, round_offset, shift, clip_low, clip_high, max_mask);
  
      dst += dst_stride * 2;
      src0 += src0_stride * 2;
      src1 += src1_stride * 2;
      mask += mask_stride * 4;
    } while (h -= 2);
  }
  
  static INLINE void highbd_blend_a64_d16_mask_w16_sse4_1(
      uint16_t *dst, const CONV_BUF_TYPE *src0, const CONV_BUF_TYPE *src1,
      const __m128i *round_offset, int shift, const __m128i *mask0l,
      const __m128i *mask0h, const __m128i *clip_low, const __m128i *clip_high,
      const __m128i *mask_max) {
    // Load 16x u16 pixels for this row from each src
    const __m128i s0l = xx_loadu_128(src0);
    const __m128i s0h = xx_loadu_128(src0 + 8);
    const __m128i s1l = xx_loadu_128(src1);
    const __m128i s1h = xx_loadu_128(src1 + 8);
  
    // Calculate inverse masks
    const __m128i mask1h = _mm_sub_epi16(*mask_max, *mask0h);
    const __m128i mask1l = _mm_sub_epi16(*mask_max, *mask0l);
  
    const __m128i mul0_highs = _mm_mulhi_epu16(*mask0h, s0h);
    const __m128i mul0_lows = _mm_mullo_epi16(*mask0h, s0h);
    const __m128i mul0h = _mm_unpackhi_epi16(mul0_lows, mul0_highs);
    const __m128i mul0l = _mm_unpacklo_epi16(mul0_lows, mul0_highs);
  
    const __m128i mul1_highs = _mm_mulhi_epu16(mask1h, s1h);
    const __m128i mul1_lows = _mm_mullo_epi16(mask1h, s1h);
    const __m128i mul1h = _mm_unpackhi_epi16(mul1_lows, mul1_highs);
    const __m128i mul1l = _mm_unpacklo_epi16(mul1_lows, mul1_highs);
  
    const __m128i mulhh = _mm_add_epi32(mul0h, mul1h);
    const __m128i mulhl = _mm_add_epi32(mul0l, mul1l);
  
    const __m128i mul2_highs = _mm_mulhi_epu16(*mask0l, s0l);
    const __m128i mul2_lows = _mm_mullo_epi16(*mask0l, s0l);
    const __m128i mul2h = _mm_unpackhi_epi16(mul2_lows, mul2_highs);
    const __m128i mul2l = _mm_unpacklo_epi16(mul2_lows, mul2_highs);
  
    const __m128i mul3_highs = _mm_mulhi_epu16(mask1l, s1l);
    const __m128i mul3_lows = _mm_mullo_epi16(mask1l, s1l);
    const __m128i mul3h = _mm_unpackhi_epi16(mul3_lows, mul3_highs);
    const __m128i mul3l = _mm_unpacklo_epi16(mul3_lows, mul3_highs);
  
    const __m128i mullh = _mm_add_epi32(mul2h, mul3h);
    const __m128i mulll = _mm_add_epi32(mul2l, mul3l);
  
    const __m128i reshh =
        _mm_srai_epi32(_mm_sub_epi32(mulhh, *round_offset), shift);
    const __m128i reshl =
        _mm_srai_epi32(_mm_sub_epi32(mulhl, *round_offset), shift);
    const __m128i reslh =
        _mm_srai_epi32(_mm_sub_epi32(mullh, *round_offset), shift);
    const __m128i resll =
        _mm_srai_epi32(_mm_sub_epi32(mulll, *round_offset), shift);
  
    // Signed saturating pack from i32 to i16:
    const __m128i packh = _mm_packs_epi32(reshl, reshh);
    const __m128i packl = _mm_packs_epi32(resll, reslh);
  
    // Clip the values to the valid range
    const __m128i cliph =
        _mm_min_epi16(_mm_max_epi16(packh, *clip_low), *clip_high);
    const __m128i clipl =
        _mm_min_epi16(_mm_max_epi16(packl, *clip_low), *clip_high);
  
    // Store 16 pixels
    xx_storeu_128(dst, clipl);
    xx_storeu_128(dst + 8, cliph);
  }
  
  static INLINE void highbd_blend_a64_d16_mask_subw0_subh0_w16_sse4_1(
      uint16_t *dst, uint32_t dst_stride, const CONV_BUF_TYPE *src0,
      uint32_t src0_stride, const CONV_BUF_TYPE *src1, uint32_t src1_stride,
      const uint8_t *mask, uint32_t mask_stride, int h, int w,
      const __m128i *round_offset, int shift, const __m128i *clip_low,
      const __m128i *clip_high, const __m128i *mask_max) {
    for (int i = 0; i < h; i++) {
      for (int j = 0; j < w; j += 16) {
        // Load 16x u8 alpha-mask values and pad to u16
        const __m128i masks_u8 = xx_loadu_128(mask + j);
        const __m128i mask0l = _mm_cvtepu8_epi16(masks_u8);
        const __m128i mask0h = _mm_cvtepu8_epi16(_mm_srli_si128(masks_u8, 8));
  
        highbd_blend_a64_d16_mask_w16_sse4_1(
            dst + j, src0 + j, src1 + j, round_offset, shift, &mask0l, &mask0h,
            clip_low, clip_high, mask_max);
      }
      dst += dst_stride;
      src0 += src0_stride;
      src1 += src1_stride;
      mask += mask_stride;
    }
  }
  
  static INLINE void highbd_blend_a64_d16_mask_subw1_subh1_w16_sse4_1(
      uint16_t *dst, uint32_t dst_stride, const CONV_BUF_TYPE *src0,
      uint32_t src0_stride, const CONV_BUF_TYPE *src1, uint32_t src1_stride,
      const uint8_t *mask, uint32_t mask_stride, int h, int w,
      const __m128i *round_offset, int shift, const __m128i *clip_low,
      const __m128i *clip_high, const __m128i *mask_max) {
    const __m128i one_b = _mm_set1_epi8(1);
    const __m128i two_w = _mm_set1_epi16(2);
    for (int i = 0; i < h; i++) {
      for (int j = 0; j < w; j += 16) {
        const __m128i m_i00 = xx_loadu_128(mask + 2 * j);
        const __m128i m_i01 = xx_loadu_128(mask + 2 * j + 16);
        const __m128i m_i10 = xx_loadu_128(mask + mask_stride + 2 * j);
        const __m128i m_i11 = xx_loadu_128(mask + mask_stride + 2 * j + 16);
  
        const __m128i m0_ac = _mm_adds_epu8(m_i00, m_i10);
        const __m128i m1_ac = _mm_adds_epu8(m_i01, m_i11);
        const __m128i m0_acbd = _mm_maddubs_epi16(m0_ac, one_b);
        const __m128i m1_acbd = _mm_maddubs_epi16(m1_ac, one_b);
        const __m128i mask_l = _mm_srli_epi16(_mm_add_epi16(m0_acbd, two_w), 2);
        const __m128i mask_h = _mm_srli_epi16(_mm_add_epi16(m1_acbd, two_w), 2);
  
        highbd_blend_a64_d16_mask_w16_sse4_1(
            dst + j, src0 + j, src1 + j, round_offset, shift, &mask_l, &mask_h,
            clip_low, clip_high, mask_max);
      }
      dst += dst_stride;
      src0 += src0_stride;
      src1 += src1_stride;
      mask += mask_stride * 2;
    }
  }
  
  void aom_highbd_blend_a64_d16_mask_sse4_1(
      uint8_t *dst8, uint32_t dst_stride, const CONV_BUF_TYPE *src0,
      uint32_t src0_stride, const CONV_BUF_TYPE *src1, uint32_t src1_stride,
      const uint8_t *mask, uint32_t mask_stride, int w, int h, int subw, int subh,
      ConvolveParams *conv_params, const int bd) {
    uint16_t *dst = CONVERT_TO_SHORTPTR(dst8);
    const int round_bits =
        2 * FILTER_BITS - conv_params->round_0 - conv_params->round_1;
    const int32_t round_offset =
        ((1 << (round_bits + bd)) + (1 << (round_bits + bd - 1)) -
         (1 << (round_bits - 1)))
        << AOM_BLEND_A64_ROUND_BITS;
    const __m128i v_round_offset = _mm_set1_epi32(round_offset);
    const int shift = round_bits + AOM_BLEND_A64_ROUND_BITS;
  
    const __m128i clip_low = _mm_set1_epi16(0);
    const __m128i clip_high = _mm_set1_epi16((1 << bd) - 1);
    const __m128i mask_max = _mm_set1_epi16(AOM_BLEND_A64_MAX_ALPHA);
  
    assert(IMPLIES((void *)src0 == dst, src0_stride == dst_stride));
    assert(IMPLIES((void *)src1 == dst, src1_stride == dst_stride));
  
    assert(h >= 4);
    assert(w >= 4);
    assert(IS_POWER_OF_TWO(h));
    assert(IS_POWER_OF_TWO(w));
  
    if (subw == 0 && subh == 0) {
      switch (w) {
        case 4:
          highbd_blend_a64_d16_mask_subw0_subh0_w4_sse4_1(
              dst, dst_stride, src0, src0_stride, src1, src1_stride, mask,
              mask_stride, h, &v_round_offset, shift, &clip_low, &clip_high,
              &mask_max);
          break;
        case 8:
          highbd_blend_a64_d16_mask_subw0_subh0_w8_sse4_1(
              dst, dst_stride, src0, src0_stride, src1, src1_stride, mask,
              mask_stride, h, &v_round_offset, shift, &clip_low, &clip_high,
              &mask_max);
          break;
        default:  // >=16
          highbd_blend_a64_d16_mask_subw0_subh0_w16_sse4_1(
              dst, dst_stride, src0, src0_stride, src1, src1_stride, mask,
              mask_stride, h, w, &v_round_offset, shift, &clip_low, &clip_high,
              &mask_max);
          break;
      }
  
    } else if (subw == 1 && subh == 1) {
      switch (w) {
        case 4:
          highbd_blend_a64_d16_mask_subw1_subh1_w4_sse4_1(
              dst, dst_stride, src0, src0_stride, src1, src1_stride, mask,
              mask_stride, h, &v_round_offset, shift, &clip_low, &clip_high,
              &mask_max);
          break;
        case 8:
          highbd_blend_a64_d16_mask_subw1_subh1_w8_sse4_1(
              dst, dst_stride, src0, src0_stride, src1, src1_stride, mask,
              mask_stride, h, &v_round_offset, shift, &clip_low, &clip_high,
              &mask_max);
          break;
        default:  // >=16
          highbd_blend_a64_d16_mask_subw1_subh1_w16_sse4_1(
              dst, dst_stride, src0, src0_stride, src1, src1_stride, mask,
              mask_stride, h, w, &v_round_offset, shift, &clip_low, &clip_high,
              &mask_max);
          break;
      }
    } else {
      // Sub-sampling in only one axis doesn't seem to happen very much, so fall
      // back to the vanilla C implementation instead of having all the optimised
      // code for these.
      aom_highbd_blend_a64_d16_mask_c(dst8, dst_stride, src0, src0_stride, src1,
                                      src1_stride, mask, mask_stride, w, h, subw,
                                      subh, conv_params, bd);
    }
  }
  