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vpx_convolve8_neon_i8mm.c (36254B)


      1 /*
      2 *  Copyright (c) 2023 The WebM project authors. All Rights Reserved.
      3 *
      4 *  Use of this source code is governed by a BSD-style license
      5 *  that can be found in the LICENSE file in the root of the source
      6 *  tree. An additional intellectual property rights grant can be found
      7 *  in the file PATENTS.  All contributing project authors may
      8 *  be found in the AUTHORS file in the root of the source tree.
      9 */
     10 
     11 #include <arm_neon.h>
     12 #include <assert.h>
     13 
     14 #include "./vpx_config.h"
     15 #include "./vpx_dsp_rtcd.h"
     16 #include "vpx/vpx_integer.h"
     17 #include "vpx_dsp/arm/mem_neon.h"
     18 #include "vpx_dsp/arm/transpose_neon.h"
     19 #include "vpx_dsp/arm/vpx_convolve8_neon.h"
     20 #include "vpx_dsp/vpx_filter.h"
     21 #include "vpx_ports/mem.h"
     22 
     23 DECLARE_ALIGNED(16, static const uint8_t, dot_prod_permute_tbl[48]) = {
     24  0, 1, 2,  3,  1, 2,  3,  4,  2,  3,  4,  5,  3,  4,  5,  6,
     25  4, 5, 6,  7,  5, 6,  7,  8,  6,  7,  8,  9,  7,  8,  9,  10,
     26  8, 9, 10, 11, 9, 10, 11, 12, 10, 11, 12, 13, 11, 12, 13, 14
     27 };
     28 
     29 DECLARE_ALIGNED(16, static const uint8_t, dot_prod_merge_block_tbl[48]) = {
     30  // Shift left and insert new last column in transposed 4x4 block.
     31  1, 2, 3, 16, 5, 6, 7, 20, 9, 10, 11, 24, 13, 14, 15, 28,
     32  // Shift left and insert two new columns in transposed 4x4 block.
     33  2, 3, 16, 17, 6, 7, 20, 21, 10, 11, 24, 25, 14, 15, 28, 29,
     34  // Shift left and insert three new columns in transposed 4x4 block.
     35  3, 16, 17, 18, 7, 20, 21, 22, 11, 24, 25, 26, 15, 28, 29, 30
     36 };
     37 
     38 static INLINE int16x4_t convolve4_4_h(const uint8x16_t samples,
     39                                      const int8x8_t filters,
     40                                      const uint8x16_t permute_tbl) {
     41  // Permute samples ready for dot product.
     42  // { 0,  1,  2,  3,  1,  2,  3,  4,  2,  3,  4,  5,  3,  4,  5,  6 }
     43  uint8x16_t permuted_samples = vqtbl1q_u8(samples, permute_tbl);
     44 
     45  int32x4_t sum =
     46      vusdotq_lane_s32(vdupq_n_s32(0), permuted_samples, filters, 0);
     47 
     48  // Further narrowing and packing is performed by the caller.
     49  return vmovn_s32(sum);
     50 }
     51 
     52 static INLINE uint8x8_t convolve4_8_h(const uint8x16_t samples,
     53                                      const int8x8_t filters,
     54                                      const uint8x16x2_t permute_tbl) {
     55  // Permute samples ready for dot product.
     56  // { 0,  1,  2,  3,  1,  2,  3,  4,  2,  3,  4,  5,  3,  4,  5,  6 }
     57  // { 4,  5,  6,  7,  5,  6,  7,  8,  6,  7,  8,  9,  7,  8,  9, 10 }
     58  uint8x16_t permuted_samples[2] = { vqtbl1q_u8(samples, permute_tbl.val[0]),
     59                                     vqtbl1q_u8(samples, permute_tbl.val[1]) };
     60 
     61  // First 4 output values.
     62  int32x4_t sum0 =
     63      vusdotq_lane_s32(vdupq_n_s32(0), permuted_samples[0], filters, 0);
     64  // Second 4 output values.
     65  int32x4_t sum1 =
     66      vusdotq_lane_s32(vdupq_n_s32(0), permuted_samples[1], filters, 0);
     67 
     68  // Narrow and re-pack.
     69  int16x8_t sum = vcombine_s16(vmovn_s32(sum0), vmovn_s32(sum1));
     70  // We halved the filter values so -1 from right shift.
     71  return vqrshrun_n_s16(sum, FILTER_BITS - 1);
     72 }
     73 
     74 static INLINE int16x4_t convolve8_4_h(const uint8x16_t samples,
     75                                      const int8x8_t filters,
     76                                      const uint8x16x2_t permute_tbl) {
     77  // Permute samples ready for dot product.
     78  // { 0,  1,  2,  3,  1,  2,  3,  4,  2,  3,  4,  5,  3,  4,  5,  6 }
     79  // { 4,  5,  6,  7,  5,  6,  7,  8,  6,  7,  8,  9,  7,  8,  9, 10 }
     80  uint8x16_t permuted_samples[2] = { vqtbl1q_u8(samples, permute_tbl.val[0]),
     81                                     vqtbl1q_u8(samples, permute_tbl.val[1]) };
     82 
     83  int32x4_t sum =
     84      vusdotq_lane_s32(vdupq_n_s32(0), permuted_samples[0], filters, 0);
     85  sum = vusdotq_lane_s32(sum, permuted_samples[1], filters, 1);
     86 
     87  // Further narrowing and packing is performed by the caller.
     88  return vshrn_n_s32(sum, 1);
     89 }
     90 
     91 static INLINE uint8x8_t convolve8_8_h(const uint8x16_t samples,
     92                                      const int8x8_t filters,
     93                                      const uint8x16x3_t permute_tbl) {
     94  // Permute samples ready for dot product.
     95  // { 0,  1,  2,  3,  1,  2,  3,  4,  2,  3,  4,  5,  3,  4,  5,  6 }
     96  // { 4,  5,  6,  7,  5,  6,  7,  8,  6,  7,  8,  9,  7,  8,  9, 10 }
     97  // { 8,  9, 10, 11,  9, 10, 11, 12, 10, 11, 12, 13, 11, 12, 13, 14 }
     98  uint8x16_t permuted_samples[3] = { vqtbl1q_u8(samples, permute_tbl.val[0]),
     99                                     vqtbl1q_u8(samples, permute_tbl.val[1]),
    100                                     vqtbl1q_u8(samples, permute_tbl.val[2]) };
    101 
    102  // First 4 output values.
    103  int32x4_t sum0 =
    104      vusdotq_lane_s32(vdupq_n_s32(0), permuted_samples[0], filters, 0);
    105  sum0 = vusdotq_lane_s32(sum0, permuted_samples[1], filters, 1);
    106  // Second 4 output values.
    107  int32x4_t sum1 =
    108      vusdotq_lane_s32(vdupq_n_s32(0), permuted_samples[1], filters, 0);
    109  sum1 = vusdotq_lane_s32(sum1, permuted_samples[2], filters, 1);
    110 
    111  // Narrow and re-pack.
    112  int16x8_t sum = vcombine_s16(vshrn_n_s32(sum0, 1), vshrn_n_s32(sum1, 1));
    113  return vqrshrun_n_s16(sum, FILTER_BITS - 1);
    114 }
    115 
    116 static INLINE void convolve_4tap_horiz_neon_i8mm(const uint8_t *src,
    117                                                 ptrdiff_t src_stride,
    118                                                 uint8_t *dst,
    119                                                 ptrdiff_t dst_stride, int w,
    120                                                 int h, const int8x8_t filter) {
    121  if (w == 4) {
    122    const uint8x16_t permute_tbl = vld1q_u8(dot_prod_permute_tbl);
    123 
    124    do {
    125      uint8x16_t s0, s1, s2, s3;
    126      load_u8_16x4(src, src_stride, &s0, &s1, &s2, &s3);
    127 
    128      int16x4_t t0 = convolve4_4_h(s0, filter, permute_tbl);
    129      int16x4_t t1 = convolve4_4_h(s1, filter, permute_tbl);
    130      int16x4_t t2 = convolve4_4_h(s2, filter, permute_tbl);
    131      int16x4_t t3 = convolve4_4_h(s3, filter, permute_tbl);
    132      // We halved the filter values so -1 from right shift.
    133      uint8x8_t d01 = vqrshrun_n_s16(vcombine_s16(t0, t1), FILTER_BITS - 1);
    134      uint8x8_t d23 = vqrshrun_n_s16(vcombine_s16(t2, t3), FILTER_BITS - 1);
    135 
    136      store_u8(dst + 0 * dst_stride, dst_stride, d01);
    137      store_u8(dst + 2 * dst_stride, dst_stride, d23);
    138 
    139      src += 4 * src_stride;
    140      dst += 4 * dst_stride;
    141      h -= 4;
    142    } while (h != 0);
    143  } else {
    144    const uint8x16x2_t permute_tbl = vld1q_u8_x2(dot_prod_permute_tbl);
    145 
    146    do {
    147      const uint8_t *s = src;
    148      uint8_t *d = dst;
    149      int width = w;
    150 
    151      do {
    152        uint8x16_t s0, s1, s2, s3;
    153        load_u8_16x4(s, src_stride, &s0, &s1, &s2, &s3);
    154 
    155        uint8x8_t d0 = convolve4_8_h(s0, filter, permute_tbl);
    156        uint8x8_t d1 = convolve4_8_h(s1, filter, permute_tbl);
    157        uint8x8_t d2 = convolve4_8_h(s2, filter, permute_tbl);
    158        uint8x8_t d3 = convolve4_8_h(s3, filter, permute_tbl);
    159 
    160        store_u8_8x4(d, dst_stride, d0, d1, d2, d3);
    161 
    162        s += 8;
    163        d += 8;
    164        width -= 8;
    165      } while (width != 0);
    166      src += 4 * src_stride;
    167      dst += 4 * dst_stride;
    168      h -= 4;
    169    } while (h != 0);
    170  }
    171 }
    172 
    173 static INLINE void convolve_8tap_horiz_neon_i8mm(const uint8_t *src,
    174                                                 ptrdiff_t src_stride,
    175                                                 uint8_t *dst,
    176                                                 ptrdiff_t dst_stride, int w,
    177                                                 int h, const int8x8_t filter) {
    178  if (w == 4) {
    179    const uint8x16x2_t permute_tbl = vld1q_u8_x2(dot_prod_permute_tbl);
    180 
    181    do {
    182      uint8x16_t s0, s1, s2, s3;
    183      load_u8_16x4(src, src_stride, &s0, &s1, &s2, &s3);
    184 
    185      int16x4_t t0 = convolve8_4_h(s0, filter, permute_tbl);
    186      int16x4_t t1 = convolve8_4_h(s1, filter, permute_tbl);
    187      int16x4_t t2 = convolve8_4_h(s2, filter, permute_tbl);
    188      int16x4_t t3 = convolve8_4_h(s3, filter, permute_tbl);
    189      uint8x8_t d01 = vqrshrun_n_s16(vcombine_s16(t0, t1), FILTER_BITS - 1);
    190      uint8x8_t d23 = vqrshrun_n_s16(vcombine_s16(t2, t3), FILTER_BITS - 1);
    191 
    192      store_u8(dst + 0 * dst_stride, dst_stride, d01);
    193      store_u8(dst + 2 * dst_stride, dst_stride, d23);
    194 
    195      src += 4 * src_stride;
    196      dst += 4 * dst_stride;
    197      h -= 4;
    198    } while (h != 0);
    199  } else {
    200    const uint8x16x3_t permute_tbl = vld1q_u8_x3(dot_prod_permute_tbl);
    201 
    202    do {
    203      const uint8_t *s = src;
    204      uint8_t *d = dst;
    205      int width = w;
    206 
    207      do {
    208        uint8x16_t s0, s1, s2, s3;
    209        load_u8_16x4(s, src_stride, &s0, &s1, &s2, &s3);
    210 
    211        uint8x8_t d0 = convolve8_8_h(s0, filter, permute_tbl);
    212        uint8x8_t d1 = convolve8_8_h(s1, filter, permute_tbl);
    213        uint8x8_t d2 = convolve8_8_h(s2, filter, permute_tbl);
    214        uint8x8_t d3 = convolve8_8_h(s3, filter, permute_tbl);
    215 
    216        store_u8_8x4(d, dst_stride, d0, d1, d2, d3);
    217 
    218        s += 8;
    219        d += 8;
    220        width -= 8;
    221      } while (width != 0);
    222      src += 4 * src_stride;
    223      dst += 4 * dst_stride;
    224      h -= 4;
    225    } while (h != 0);
    226  }
    227 }
    228 
    229 void vpx_convolve8_horiz_neon_i8mm(const uint8_t *src, ptrdiff_t src_stride,
    230                                   uint8_t *dst, ptrdiff_t dst_stride,
    231                                   const InterpKernel *filter, int x0_q4,
    232                                   int x_step_q4, int y0_q4, int y_step_q4,
    233                                   int w, int h) {
    234  assert((intptr_t)dst % 4 == 0);
    235  assert(dst_stride % 4 == 0);
    236  assert(x_step_q4 == 16);
    237 
    238  (void)x_step_q4;
    239  (void)y0_q4;
    240  (void)y_step_q4;
    241 
    242  if (vpx_get_filter_taps(filter[x0_q4]) <= 4) {
    243    // Load 4-tap filter into first 4 elements of the vector.
    244    // All 4-tap and bilinear filter values are even, so halve them to reduce
    245    // intermediate precision requirements.
    246    const int16x4_t x_filter = vld1_s16(filter[x0_q4] + 2);
    247    const int8x8_t x_filter_4tap =
    248        vshrn_n_s16(vcombine_s16(x_filter, vdup_n_s16(0)), 1);
    249 
    250    convolve_4tap_horiz_neon_i8mm(src - 1, src_stride, dst, dst_stride, w, h,
    251                                  x_filter_4tap);
    252 
    253  } else {
    254    const int8x8_t x_filter_8tap = vmovn_s16(vld1q_s16(filter[x0_q4]));
    255 
    256    convolve_8tap_horiz_neon_i8mm(src - 3, src_stride, dst, dst_stride, w, h,
    257                                  x_filter_8tap);
    258  }
    259 }
    260 
    261 void vpx_convolve8_avg_horiz_neon_i8mm(const uint8_t *src, ptrdiff_t src_stride,
    262                                       uint8_t *dst, ptrdiff_t dst_stride,
    263                                       const InterpKernel *filter, int x0_q4,
    264                                       int x_step_q4, int y0_q4, int y_step_q4,
    265                                       int w, int h) {
    266  const int8x8_t filters = vmovn_s16(vld1q_s16(filter[x0_q4]));
    267 
    268  assert((intptr_t)dst % 4 == 0);
    269  assert(dst_stride % 4 == 0);
    270  assert(x_step_q4 == 16);
    271 
    272  (void)x_step_q4;
    273  (void)y0_q4;
    274  (void)y_step_q4;
    275 
    276  src -= 3;
    277 
    278  if (w == 4) {
    279    const uint8x16x2_t permute_tbl = vld1q_u8_x2(dot_prod_permute_tbl);
    280 
    281    do {
    282      uint8x16_t s0, s1, s2, s3;
    283      load_u8_16x4(src, src_stride, &s0, &s1, &s2, &s3);
    284 
    285      int16x4_t t0 = convolve8_4_h(s0, filters, permute_tbl);
    286      int16x4_t t1 = convolve8_4_h(s1, filters, permute_tbl);
    287      int16x4_t t2 = convolve8_4_h(s2, filters, permute_tbl);
    288      int16x4_t t3 = convolve8_4_h(s3, filters, permute_tbl);
    289      uint8x8_t d01 = vqrshrun_n_s16(vcombine_s16(t0, t1), FILTER_BITS - 1);
    290      uint8x8_t d23 = vqrshrun_n_s16(vcombine_s16(t2, t3), FILTER_BITS - 1);
    291 
    292      uint8x8_t dd01 = load_u8(dst + 0 * dst_stride, dst_stride);
    293      uint8x8_t dd23 = load_u8(dst + 2 * dst_stride, dst_stride);
    294 
    295      d01 = vrhadd_u8(d01, dd01);
    296      d23 = vrhadd_u8(d23, dd23);
    297 
    298      store_u8(dst + 0 * dst_stride, dst_stride, d01);
    299      store_u8(dst + 2 * dst_stride, dst_stride, d23);
    300 
    301      src += 4 * src_stride;
    302      dst += 4 * dst_stride;
    303      h -= 4;
    304    } while (h != 0);
    305  } else {
    306    const uint8x16x3_t permute_tbl = vld1q_u8_x3(dot_prod_permute_tbl);
    307 
    308    do {
    309      const uint8_t *s = src;
    310      uint8_t *d = dst;
    311      int width = w;
    312 
    313      do {
    314        uint8x16_t s0, s1, s2, s3;
    315        load_u8_16x4(s, src_stride, &s0, &s1, &s2, &s3);
    316 
    317        uint8x8_t d0 = convolve8_8_h(s0, filters, permute_tbl);
    318        uint8x8_t d1 = convolve8_8_h(s1, filters, permute_tbl);
    319        uint8x8_t d2 = convolve8_8_h(s2, filters, permute_tbl);
    320        uint8x8_t d3 = convolve8_8_h(s3, filters, permute_tbl);
    321 
    322        uint8x8_t dd0, dd1, dd2, dd3;
    323        load_u8_8x4(d, dst_stride, &dd0, &dd1, &dd2, &dd3);
    324 
    325        d0 = vrhadd_u8(d0, dd0);
    326        d1 = vrhadd_u8(d1, dd1);
    327        d2 = vrhadd_u8(d2, dd2);
    328        d3 = vrhadd_u8(d3, dd3);
    329 
    330        store_u8_8x4(d, dst_stride, d0, d1, d2, d3);
    331 
    332        s += 8;
    333        d += 8;
    334        width -= 8;
    335      } while (width != 0);
    336      src += 4 * src_stride;
    337      dst += 4 * dst_stride;
    338      h -= 4;
    339    } while (h != 0);
    340  }
    341 }
    342 
    343 static INLINE int16x4_t convolve8_4_v(const uint8x16_t samples_lo,
    344                                      const uint8x16_t samples_hi,
    345                                      const int8x8_t filters) {
    346  // Sample permutation is performed by the caller.
    347  int32x4_t sum = vusdotq_lane_s32(vdupq_n_s32(0), samples_lo, filters, 0);
    348  sum = vusdotq_lane_s32(sum, samples_hi, filters, 1);
    349 
    350  // Further narrowing and packing is performed by the caller.
    351  return vshrn_n_s32(sum, 1);
    352 }
    353 
    354 static INLINE uint8x8_t convolve8_8_v(const uint8x16_t samples0_lo,
    355                                      const uint8x16_t samples0_hi,
    356                                      const uint8x16_t samples1_lo,
    357                                      const uint8x16_t samples1_hi,
    358                                      const int8x8_t filters) {
    359  // Sample permutation is performed by the caller.
    360 
    361  // First 4 output values.
    362  int32x4_t sum0 = vusdotq_lane_s32(vdupq_n_s32(0), samples0_lo, filters, 0);
    363  sum0 = vusdotq_lane_s32(sum0, samples0_hi, filters, 1);
    364  // Second 4 output values.
    365  int32x4_t sum1 = vusdotq_lane_s32(vdupq_n_s32(0), samples1_lo, filters, 0);
    366  sum1 = vusdotq_lane_s32(sum1, samples1_hi, filters, 1);
    367 
    368  // Narrow and re-pack.
    369  int16x8_t sum = vcombine_s16(vshrn_n_s32(sum0, 1), vshrn_n_s32(sum1, 1));
    370  return vqrshrun_n_s16(sum, FILTER_BITS - 1);
    371 }
    372 
    373 static INLINE void convolve_8tap_vert_neon_i8mm(const uint8_t *src,
    374                                                ptrdiff_t src_stride,
    375                                                uint8_t *dst,
    376                                                ptrdiff_t dst_stride, int w,
    377                                                int h, const int8x8_t filter) {
    378  const uint8x16x3_t merge_block_tbl = vld1q_u8_x3(dot_prod_merge_block_tbl);
    379  if (w == 4) {
    380    uint8x8_t s0, s1, s2, s3, s4, s5, s6;
    381    load_u8_8x7(src, src_stride, &s0, &s1, &s2, &s3, &s4, &s5, &s6);
    382    src += 7 * src_stride;
    383 
    384    // This operation combines a conventional transpose and the sample permute
    385    // (see horizontal case) required before computing the dot product.
    386    uint8x16_t s0123, s1234, s2345, s3456;
    387    transpose_concat_u8_4x4(s0, s1, s2, s3, &s0123);
    388    transpose_concat_u8_4x4(s1, s2, s3, s4, &s1234);
    389    transpose_concat_u8_4x4(s2, s3, s4, s5, &s2345);
    390    transpose_concat_u8_4x4(s3, s4, s5, s6, &s3456);
    391 
    392    do {
    393      uint8x8_t s7, s8, s9, s10;
    394      load_u8_8x4(src, src_stride, &s7, &s8, &s9, &s10);
    395 
    396      uint8x16_t s78910;
    397      transpose_concat_u8_4x4(s7, s8, s9, s10, &s78910);
    398 
    399      // Merge new data into block from previous iteration.
    400      uint8x16x2_t samples_LUT = { { s3456, s78910 } };
    401      uint8x16_t s4567 = vqtbl2q_u8(samples_LUT, merge_block_tbl.val[0]);
    402      uint8x16_t s5678 = vqtbl2q_u8(samples_LUT, merge_block_tbl.val[1]);
    403      uint8x16_t s6789 = vqtbl2q_u8(samples_LUT, merge_block_tbl.val[2]);
    404 
    405      int16x4_t d0 = convolve8_4_v(s0123, s4567, filter);
    406      int16x4_t d1 = convolve8_4_v(s1234, s5678, filter);
    407      int16x4_t d2 = convolve8_4_v(s2345, s6789, filter);
    408      int16x4_t d3 = convolve8_4_v(s3456, s78910, filter);
    409      uint8x8_t d01 = vqrshrun_n_s16(vcombine_s16(d0, d1), FILTER_BITS - 1);
    410      uint8x8_t d23 = vqrshrun_n_s16(vcombine_s16(d2, d3), FILTER_BITS - 1);
    411 
    412      store_u8(dst + 0 * dst_stride, dst_stride, d01);
    413      store_u8(dst + 2 * dst_stride, dst_stride, d23);
    414 
    415      // Prepare block for next iteration - re-using as much as possible.
    416      // Shuffle everything up four rows.
    417      s0123 = s4567;
    418      s1234 = s5678;
    419      s2345 = s6789;
    420      s3456 = s78910;
    421 
    422      src += 4 * src_stride;
    423      dst += 4 * dst_stride;
    424      h -= 4;
    425    } while (h != 0);
    426  } else {
    427    do {
    428      const uint8_t *s = src;
    429      uint8_t *d = dst;
    430      int height = h;
    431 
    432      uint8x8_t s0, s1, s2, s3, s4, s5, s6;
    433      load_u8_8x7(s, src_stride, &s0, &s1, &s2, &s3, &s4, &s5, &s6);
    434      s += 7 * src_stride;
    435 
    436      // This operation combines a conventional transpose and the sample permute
    437      // (see horizontal case) required before computing the dot product.
    438      uint8x16_t s0123_lo, s0123_hi, s1234_lo, s1234_hi, s2345_lo, s2345_hi,
    439          s3456_lo, s3456_hi;
    440      transpose_concat_u8_8x4(s0, s1, s2, s3, &s0123_lo, &s0123_hi);
    441      transpose_concat_u8_8x4(s1, s2, s3, s4, &s1234_lo, &s1234_hi);
    442      transpose_concat_u8_8x4(s2, s3, s4, s5, &s2345_lo, &s2345_hi);
    443      transpose_concat_u8_8x4(s3, s4, s5, s6, &s3456_lo, &s3456_hi);
    444 
    445      do {
    446        uint8x8_t s7, s8, s9, s10;
    447        load_u8_8x4(s, src_stride, &s7, &s8, &s9, &s10);
    448 
    449        uint8x16_t s78910_lo, s78910_hi;
    450        transpose_concat_u8_8x4(s7, s8, s9, s10, &s78910_lo, &s78910_hi);
    451 
    452        // Merge new data into block from previous iteration.
    453        uint8x16x2_t samples_LUT = { { s3456_lo, s78910_lo } };
    454        uint8x16_t s4567_lo = vqtbl2q_u8(samples_LUT, merge_block_tbl.val[0]);
    455        uint8x16_t s5678_lo = vqtbl2q_u8(samples_LUT, merge_block_tbl.val[1]);
    456        uint8x16_t s6789_lo = vqtbl2q_u8(samples_LUT, merge_block_tbl.val[2]);
    457 
    458        samples_LUT.val[0] = s3456_hi;
    459        samples_LUT.val[1] = s78910_hi;
    460        uint8x16_t s4567_hi = vqtbl2q_u8(samples_LUT, merge_block_tbl.val[0]);
    461        uint8x16_t s5678_hi = vqtbl2q_u8(samples_LUT, merge_block_tbl.val[1]);
    462        uint8x16_t s6789_hi = vqtbl2q_u8(samples_LUT, merge_block_tbl.val[2]);
    463 
    464        uint8x8_t d0 =
    465            convolve8_8_v(s0123_lo, s4567_lo, s0123_hi, s4567_hi, filter);
    466        uint8x8_t d1 =
    467            convolve8_8_v(s1234_lo, s5678_lo, s1234_hi, s5678_hi, filter);
    468        uint8x8_t d2 =
    469            convolve8_8_v(s2345_lo, s6789_lo, s2345_hi, s6789_hi, filter);
    470        uint8x8_t d3 =
    471            convolve8_8_v(s3456_lo, s78910_lo, s3456_hi, s78910_hi, filter);
    472 
    473        store_u8_8x4(d, dst_stride, d0, d1, d2, d3);
    474 
    475        // Prepare block for next iteration - re-using as much as possible.
    476        // Shuffle everything up four rows.
    477        s0123_lo = s4567_lo;
    478        s0123_hi = s4567_hi;
    479        s1234_lo = s5678_lo;
    480        s1234_hi = s5678_hi;
    481        s2345_lo = s6789_lo;
    482        s2345_hi = s6789_hi;
    483        s3456_lo = s78910_lo;
    484        s3456_hi = s78910_hi;
    485 
    486        s += 4 * src_stride;
    487        d += 4 * dst_stride;
    488        height -= 4;
    489      } while (height != 0);
    490      src += 8;
    491      dst += 8;
    492      w -= 8;
    493    } while (w != 0);
    494  }
    495 }
    496 
    497 void vpx_convolve8_vert_neon_i8mm(const uint8_t *src, ptrdiff_t src_stride,
    498                                  uint8_t *dst, ptrdiff_t dst_stride,
    499                                  const InterpKernel *filter, int x0_q4,
    500                                  int x_step_q4, int y0_q4, int y_step_q4,
    501                                  int w, int h) {
    502  assert((intptr_t)dst % 4 == 0);
    503  assert(dst_stride % 4 == 0);
    504  assert(y_step_q4 == 16);
    505 
    506  (void)x0_q4;
    507  (void)x_step_q4;
    508  (void)y_step_q4;
    509 
    510  if (vpx_get_filter_taps(filter[y0_q4]) <= 4) {
    511    const int16x8_t y_filter = vld1q_s16(filter[y0_q4]);
    512 
    513    convolve_4tap_vert_neon(src - src_stride, src_stride, dst, dst_stride, w, h,
    514                            y_filter);
    515  } else {
    516    const int8x8_t y_filter = vmovn_s16(vld1q_s16(filter[y0_q4]));
    517 
    518    convolve_8tap_vert_neon_i8mm(src - 3 * src_stride, src_stride, dst,
    519                                 dst_stride, w, h, y_filter);
    520  }
    521 }
    522 
    523 void vpx_convolve8_avg_vert_neon_i8mm(const uint8_t *src, ptrdiff_t src_stride,
    524                                      uint8_t *dst, ptrdiff_t dst_stride,
    525                                      const InterpKernel *filter, int x0_q4,
    526                                      int x_step_q4, int y0_q4, int y_step_q4,
    527                                      int w, int h) {
    528  const int8x8_t filters = vmovn_s16(vld1q_s16(filter[y0_q4]));
    529  const uint8x16x3_t merge_block_tbl = vld1q_u8_x3(dot_prod_merge_block_tbl);
    530 
    531  assert((intptr_t)dst % 4 == 0);
    532  assert(dst_stride % 4 == 0);
    533  assert(y_step_q4 == 16);
    534 
    535  (void)x0_q4;
    536  (void)x_step_q4;
    537  (void)y_step_q4;
    538 
    539  src -= 3 * src_stride;
    540 
    541  if (w == 4) {
    542    uint8x8_t s0, s1, s2, s3, s4, s5, s6;
    543    load_u8_8x7(src, src_stride, &s0, &s1, &s2, &s3, &s4, &s5, &s6);
    544    src += 7 * src_stride;
    545 
    546    // This operation combines a conventional transpose and the sample permute
    547    // (see horizontal case) required before computing the dot product.
    548    uint8x16_t s0123, s1234, s2345, s3456;
    549    transpose_concat_u8_4x4(s0, s1, s2, s3, &s0123);
    550    transpose_concat_u8_4x4(s1, s2, s3, s4, &s1234);
    551    transpose_concat_u8_4x4(s2, s3, s4, s5, &s2345);
    552    transpose_concat_u8_4x4(s3, s4, s5, s6, &s3456);
    553 
    554    do {
    555      uint8x8_t s7, s8, s9, s10;
    556      load_u8_8x4(src, src_stride, &s7, &s8, &s9, &s10);
    557 
    558      uint8x16_t s78910;
    559      transpose_concat_u8_4x4(s7, s8, s9, s10, &s78910);
    560 
    561      // Merge new data into block from previous iteration.
    562      uint8x16x2_t samples_LUT = { { s3456, s78910 } };
    563      uint8x16_t s4567 = vqtbl2q_u8(samples_LUT, merge_block_tbl.val[0]);
    564      uint8x16_t s5678 = vqtbl2q_u8(samples_LUT, merge_block_tbl.val[1]);
    565      uint8x16_t s6789 = vqtbl2q_u8(samples_LUT, merge_block_tbl.val[2]);
    566 
    567      int16x4_t d0 = convolve8_4_v(s0123, s4567, filters);
    568      int16x4_t d1 = convolve8_4_v(s1234, s5678, filters);
    569      int16x4_t d2 = convolve8_4_v(s2345, s6789, filters);
    570      int16x4_t d3 = convolve8_4_v(s3456, s78910, filters);
    571      uint8x8_t d01 = vqrshrun_n_s16(vcombine_s16(d0, d1), FILTER_BITS - 1);
    572      uint8x8_t d23 = vqrshrun_n_s16(vcombine_s16(d2, d3), FILTER_BITS - 1);
    573 
    574      uint8x8_t dd01 = load_u8(dst + 0 * dst_stride, dst_stride);
    575      uint8x8_t dd23 = load_u8(dst + 2 * dst_stride, dst_stride);
    576 
    577      d01 = vrhadd_u8(d01, dd01);
    578      d23 = vrhadd_u8(d23, dd23);
    579 
    580      store_u8(dst + 0 * dst_stride, dst_stride, d01);
    581      store_u8(dst + 2 * dst_stride, dst_stride, d23);
    582 
    583      // Prepare block for next iteration - re-using as much as possible.
    584      // Shuffle everything up four rows.
    585      s0123 = s4567;
    586      s1234 = s5678;
    587      s2345 = s6789;
    588      s3456 = s78910;
    589 
    590      src += 4 * src_stride;
    591      dst += 4 * dst_stride;
    592      h -= 4;
    593    } while (h != 0);
    594  } else {
    595    do {
    596      const uint8_t *s = src;
    597      uint8_t *d = dst;
    598      int height = h;
    599 
    600      uint8x8_t s0, s1, s2, s3, s4, s5, s6;
    601      load_u8_8x7(s, src_stride, &s0, &s1, &s2, &s3, &s4, &s5, &s6);
    602      s += 7 * src_stride;
    603 
    604      // This operation combines a conventional transpose and the sample permute
    605      // (see horizontal case) required before computing the dot product.
    606      uint8x16_t s0123_lo, s0123_hi, s1234_lo, s1234_hi, s2345_lo, s2345_hi,
    607          s3456_lo, s3456_hi;
    608      transpose_concat_u8_8x4(s0, s1, s2, s3, &s0123_lo, &s0123_hi);
    609      transpose_concat_u8_8x4(s1, s2, s3, s4, &s1234_lo, &s1234_hi);
    610      transpose_concat_u8_8x4(s2, s3, s4, s5, &s2345_lo, &s2345_hi);
    611      transpose_concat_u8_8x4(s3, s4, s5, s6, &s3456_lo, &s3456_hi);
    612 
    613      do {
    614        uint8x8_t s7, s8, s9, s10;
    615        load_u8_8x4(s, src_stride, &s7, &s8, &s9, &s10);
    616 
    617        uint8x16_t s78910_lo, s78910_hi;
    618        transpose_concat_u8_8x4(s7, s8, s9, s10, &s78910_lo, &s78910_hi);
    619 
    620        // Merge new data into block from previous iteration.
    621        uint8x16x2_t samples_LUT = { { s3456_lo, s78910_lo } };
    622        uint8x16_t s4567_lo = vqtbl2q_u8(samples_LUT, merge_block_tbl.val[0]);
    623        uint8x16_t s5678_lo = vqtbl2q_u8(samples_LUT, merge_block_tbl.val[1]);
    624        uint8x16_t s6789_lo = vqtbl2q_u8(samples_LUT, merge_block_tbl.val[2]);
    625 
    626        samples_LUT.val[0] = s3456_hi;
    627        samples_LUT.val[1] = s78910_hi;
    628        uint8x16_t s4567_hi = vqtbl2q_u8(samples_LUT, merge_block_tbl.val[0]);
    629        uint8x16_t s5678_hi = vqtbl2q_u8(samples_LUT, merge_block_tbl.val[1]);
    630        uint8x16_t s6789_hi = vqtbl2q_u8(samples_LUT, merge_block_tbl.val[2]);
    631 
    632        uint8x8_t d0 =
    633            convolve8_8_v(s0123_lo, s4567_lo, s0123_hi, s4567_hi, filters);
    634        uint8x8_t d1 =
    635            convolve8_8_v(s1234_lo, s5678_lo, s1234_hi, s5678_hi, filters);
    636        uint8x8_t d2 =
    637            convolve8_8_v(s2345_lo, s6789_lo, s2345_hi, s6789_hi, filters);
    638        uint8x8_t d3 =
    639            convolve8_8_v(s3456_lo, s78910_lo, s3456_hi, s78910_hi, filters);
    640 
    641        uint8x8_t dd0, dd1, dd2, dd3;
    642        load_u8_8x4(d, dst_stride, &dd0, &dd1, &dd2, &dd3);
    643 
    644        d0 = vrhadd_u8(d0, dd0);
    645        d1 = vrhadd_u8(d1, dd1);
    646        d2 = vrhadd_u8(d2, dd2);
    647        d3 = vrhadd_u8(d3, dd3);
    648 
    649        store_u8_8x4(d, dst_stride, d0, d1, d2, d3);
    650 
    651        /* Prepare block for next iteration - re-using as much as possible. */
    652        /* Shuffle everything up four rows. */
    653        s0123_lo = s4567_lo;
    654        s0123_hi = s4567_hi;
    655        s1234_lo = s5678_lo;
    656        s1234_hi = s5678_hi;
    657        s2345_lo = s6789_lo;
    658        s2345_hi = s6789_hi;
    659        s3456_lo = s78910_lo;
    660        s3456_hi = s78910_hi;
    661 
    662        s += 4 * src_stride;
    663        d += 4 * dst_stride;
    664        height -= 4;
    665      } while (height != 0);
    666      src += 8;
    667      dst += 8;
    668      w -= 8;
    669    } while (w != 0);
    670  }
    671 }
    672 
    673 static INLINE void convolve_4tap_2d_neon_i8mm(const uint8_t *src,
    674                                              ptrdiff_t src_stride,
    675                                              uint8_t *dst,
    676                                              ptrdiff_t dst_stride, int w,
    677                                              int h, const int8x8_t x_filter,
    678                                              const uint8x8_t y_filter) {
    679  // Neon does not have lane-referencing multiply or multiply-accumulate
    680  // instructions that operate on vectors of 8-bit elements. This means we have
    681  // to duplicate filter taps into a whole vector and use standard multiply /
    682  // multiply-accumulate instructions.
    683  const uint8x8_t y_filter_taps[4] = { vdup_lane_u8(y_filter, 2),
    684                                       vdup_lane_u8(y_filter, 3),
    685                                       vdup_lane_u8(y_filter, 4),
    686                                       vdup_lane_u8(y_filter, 5) };
    687 
    688  if (w == 4) {
    689    const uint8x16_t permute_tbl = vld1q_u8(dot_prod_permute_tbl);
    690 
    691    uint8x16_t h_s0, h_s1, h_s2;
    692    load_u8_16x3(src, src_stride, &h_s0, &h_s1, &h_s2);
    693 
    694    int16x4_t t0 = convolve4_4_h(h_s0, x_filter, permute_tbl);
    695    int16x4_t t1 = convolve4_4_h(h_s1, x_filter, permute_tbl);
    696    int16x4_t t2 = convolve4_4_h(h_s2, x_filter, permute_tbl);
    697    // We halved the filter values so -1 from right shift.
    698    uint8x8_t v_s01 = vqrshrun_n_s16(vcombine_s16(t0, t1), FILTER_BITS - 1);
    699    uint8x8_t v_s12 = vqrshrun_n_s16(vcombine_s16(t1, t2), FILTER_BITS - 1);
    700 
    701    src += 3 * src_stride;
    702 
    703    do {
    704      uint8x16_t h_s3, h_s4, h_s5, h_s6;
    705      load_u8_16x4(src, src_stride, &h_s3, &h_s4, &h_s5, &h_s6);
    706 
    707      int16x4_t t3 = convolve4_4_h(h_s3, x_filter, permute_tbl);
    708      int16x4_t t4 = convolve4_4_h(h_s4, x_filter, permute_tbl);
    709      int16x4_t t5 = convolve4_4_h(h_s5, x_filter, permute_tbl);
    710      int16x4_t t6 = convolve4_4_h(h_s6, x_filter, permute_tbl);
    711      // We halved the filter values so -1 from right shift.
    712      uint8x8_t v_s34 = vqrshrun_n_s16(vcombine_s16(t3, t4), FILTER_BITS - 1);
    713      uint8x8_t v_s56 = vqrshrun_n_s16(vcombine_s16(t5, t6), FILTER_BITS - 1);
    714      uint8x8_t v_s23 = vext_u8(v_s12, v_s34, 4);
    715      uint8x8_t v_s45 = vext_u8(v_s34, v_s56, 4);
    716 
    717      uint8x8_t d01 = convolve4_8(v_s01, v_s12, v_s23, v_s34, y_filter_taps);
    718      uint8x8_t d23 = convolve4_8(v_s23, v_s34, v_s45, v_s56, y_filter_taps);
    719 
    720      store_unaligned_u8(dst + 0 * dst_stride, dst_stride, d01);
    721      store_unaligned_u8(dst + 2 * dst_stride, dst_stride, d23);
    722 
    723      v_s01 = v_s45;
    724      v_s12 = v_s56;
    725      src += 4 * src_stride;
    726      dst += 4 * dst_stride;
    727      h -= 4;
    728    } while (h != 0);
    729  } else {
    730    const uint8x16x2_t permute_tbl = vld1q_u8_x2(dot_prod_permute_tbl);
    731 
    732    do {
    733      const uint8_t *s = src;
    734      uint8_t *d = dst;
    735      int height = h;
    736 
    737      uint8x16_t h_s0, h_s1, h_s2;
    738      load_u8_16x3(s, src_stride, &h_s0, &h_s1, &h_s2);
    739 
    740      uint8x8_t v_s0 = convolve4_8_h(h_s0, x_filter, permute_tbl);
    741      uint8x8_t v_s1 = convolve4_8_h(h_s1, x_filter, permute_tbl);
    742      uint8x8_t v_s2 = convolve4_8_h(h_s2, x_filter, permute_tbl);
    743 
    744      s += 3 * src_stride;
    745 
    746      do {
    747        uint8x16_t h_s3, h_s4, h_s5, h_s6;
    748        load_u8_16x4(s, src_stride, &h_s3, &h_s4, &h_s5, &h_s6);
    749 
    750        uint8x8_t v_s3 = convolve4_8_h(h_s3, x_filter, permute_tbl);
    751        uint8x8_t v_s4 = convolve4_8_h(h_s4, x_filter, permute_tbl);
    752        uint8x8_t v_s5 = convolve4_8_h(h_s5, x_filter, permute_tbl);
    753        uint8x8_t v_s6 = convolve4_8_h(h_s6, x_filter, permute_tbl);
    754 
    755        uint8x8_t d0 = convolve4_8(v_s0, v_s1, v_s2, v_s3, y_filter_taps);
    756        uint8x8_t d1 = convolve4_8(v_s1, v_s2, v_s3, v_s4, y_filter_taps);
    757        uint8x8_t d2 = convolve4_8(v_s2, v_s3, v_s4, v_s5, y_filter_taps);
    758        uint8x8_t d3 = convolve4_8(v_s3, v_s4, v_s5, v_s6, y_filter_taps);
    759 
    760        store_u8_8x4(d, dst_stride, d0, d1, d2, d3);
    761 
    762        v_s0 = v_s4;
    763        v_s1 = v_s5;
    764        v_s2 = v_s6;
    765        s += 4 * src_stride;
    766        d += 4 * dst_stride;
    767        height -= 4;
    768      } while (height != 0);
    769      src += 8;
    770      dst += 8;
    771      w -= 8;
    772    } while (w != 0);
    773  }
    774 }
    775 
    776 static INLINE void convolve_8tap_2d_horiz_neon_i8mm(
    777    const uint8_t *src, ptrdiff_t src_stride, uint8_t *dst,
    778    ptrdiff_t dst_stride, int w, int h, const int8x8_t filter) {
    779  if (w == 4) {
    780    const uint8x16x2_t permute_tbl = vld1q_u8_x2(dot_prod_permute_tbl);
    781 
    782    do {
    783      uint8x16_t s0, s1, s2, s3;
    784      load_u8_16x4(src, src_stride, &s0, &s1, &s2, &s3);
    785 
    786      int16x4_t d0 = convolve8_4_h(s0, filter, permute_tbl);
    787      int16x4_t d1 = convolve8_4_h(s1, filter, permute_tbl);
    788      int16x4_t d2 = convolve8_4_h(s2, filter, permute_tbl);
    789      int16x4_t d3 = convolve8_4_h(s3, filter, permute_tbl);
    790      uint8x8_t d01 = vqrshrun_n_s16(vcombine_s16(d0, d1), FILTER_BITS - 1);
    791      uint8x8_t d23 = vqrshrun_n_s16(vcombine_s16(d2, d3), FILTER_BITS - 1);
    792 
    793      store_u8(dst + 0 * dst_stride, dst_stride, d01);
    794      store_u8(dst + 2 * dst_stride, dst_stride, d23);
    795 
    796      src += 4 * src_stride;
    797      dst += 4 * dst_stride;
    798      h -= 4;
    799    } while (h > 3);
    800 
    801    // Process final three rows (h % 4 == 3). See vpx_convolve_neon_i8mm()
    802    // below for further details on possible values of block height.
    803    uint8x16_t s0, s1, s2;
    804    load_u8_16x3(src, src_stride, &s0, &s1, &s2);
    805 
    806    int16x4_t d0 = convolve8_4_h(s0, filter, permute_tbl);
    807    int16x4_t d1 = convolve8_4_h(s1, filter, permute_tbl);
    808    int16x4_t d2 = convolve8_4_h(s2, filter, permute_tbl);
    809    uint8x8_t d01 = vqrshrun_n_s16(vcombine_s16(d0, d1), FILTER_BITS - 1);
    810    uint8x8_t d23 =
    811        vqrshrun_n_s16(vcombine_s16(d2, vdup_n_s16(0)), FILTER_BITS - 1);
    812 
    813    store_u8(dst + 0 * dst_stride, dst_stride, d01);
    814    store_u8_4x1(dst + 2 * dst_stride, d23);
    815  } else {
    816    const uint8x16x3_t permute_tbl = vld1q_u8_x3(dot_prod_permute_tbl);
    817 
    818    do {
    819      const uint8_t *s = src;
    820      uint8_t *d = dst;
    821      int width = w;
    822 
    823      do {
    824        uint8x16_t s0, s1, s2, s3;
    825        load_u8_16x4(s, src_stride, &s0, &s1, &s2, &s3);
    826 
    827        uint8x8_t d0 = convolve8_8_h(s0, filter, permute_tbl);
    828        uint8x8_t d1 = convolve8_8_h(s1, filter, permute_tbl);
    829        uint8x8_t d2 = convolve8_8_h(s2, filter, permute_tbl);
    830        uint8x8_t d3 = convolve8_8_h(s3, filter, permute_tbl);
    831 
    832        store_u8_8x4(d, dst_stride, d0, d1, d2, d3);
    833 
    834        s += 8;
    835        d += 8;
    836        width -= 8;
    837      } while (width > 0);
    838      src += 4 * src_stride;
    839      dst += 4 * dst_stride;
    840      h -= 4;
    841    } while (h > 3);
    842 
    843    // Process final three rows (h % 4 == 3). See vpx_convolve_neon_i8mm()
    844    // below for further details on possible values of block height.
    845    const uint8_t *s = src;
    846    uint8_t *d = dst;
    847    int width = w;
    848 
    849    do {
    850      uint8x16_t s0, s1, s2;
    851      load_u8_16x3(s, src_stride, &s0, &s1, &s2);
    852 
    853      uint8x8_t d0 = convolve8_8_h(s0, filter, permute_tbl);
    854      uint8x8_t d1 = convolve8_8_h(s1, filter, permute_tbl);
    855      uint8x8_t d2 = convolve8_8_h(s2, filter, permute_tbl);
    856 
    857      store_u8_8x3(d, dst_stride, d0, d1, d2);
    858 
    859      s += 8;
    860      d += 8;
    861      width -= 8;
    862    } while (width > 0);
    863  }
    864 }
    865 
    866 void vpx_convolve8_neon_i8mm(const uint8_t *src, ptrdiff_t src_stride,
    867                             uint8_t *dst, ptrdiff_t dst_stride,
    868                             const InterpKernel *filter, int x0_q4,
    869                             int x_step_q4, int y0_q4, int y_step_q4, int w,
    870                             int h) {
    871  assert(x_step_q4 == 16);
    872  assert(y_step_q4 == 16);
    873 
    874  (void)x_step_q4;
    875  (void)y_step_q4;
    876 
    877  const int x_filter_taps = vpx_get_filter_taps(filter[x0_q4]) <= 4 ? 4 : 8;
    878  const int y_filter_taps = vpx_get_filter_taps(filter[y0_q4]) <= 4 ? 4 : 8;
    879  // Account for needing filter_taps / 2 - 1 lines prior and filter_taps / 2
    880  // lines post both horizontally and vertically.
    881  const ptrdiff_t horiz_offset = x_filter_taps / 2 - 1;
    882  const ptrdiff_t vert_offset = (y_filter_taps / 2 - 1) * src_stride;
    883 
    884  if (x_filter_taps == 4 && y_filter_taps == 4) {
    885    const int16x4_t x_filter = vld1_s16(filter[x0_q4] + 2);
    886    const int16x8_t y_filter = vld1q_s16(filter[y0_q4]);
    887 
    888    // 4-tap and bilinear filter values are even, so halve them to reduce
    889    // intermediate precision requirements.
    890    const int8x8_t x_filter_4tap =
    891        vshrn_n_s16(vcombine_s16(x_filter, vdup_n_s16(0)), 1);
    892    const uint8x8_t y_filter_4tap =
    893        vshrn_n_u16(vreinterpretq_u16_s16(vabsq_s16(y_filter)), 1);
    894 
    895    convolve_4tap_2d_neon_i8mm(src - horiz_offset - vert_offset, src_stride,
    896                               dst, dst_stride, w, h, x_filter_4tap,
    897                               y_filter_4tap);
    898    return;
    899  }
    900 
    901  // Given our constraints: w <= 64, h <= 64, taps <= 8 we can reduce the
    902  // maximum buffer size to 64 * (64 + 7).
    903  DECLARE_ALIGNED(32, uint8_t, im_block[64 * 71]);
    904  const int im_stride = 64;
    905  const int im_height = h + SUBPEL_TAPS - 1;
    906 
    907  const int8x8_t x_filter_8tap = vmovn_s16(vld1q_s16(filter[x0_q4]));
    908  const int8x8_t y_filter_8tap = vmovn_s16(vld1q_s16(filter[y0_q4]));
    909 
    910  convolve_8tap_2d_horiz_neon_i8mm(src - horiz_offset - vert_offset, src_stride,
    911                                   im_block, im_stride, w, im_height,
    912                                   x_filter_8tap);
    913 
    914  convolve_8tap_vert_neon_i8mm(im_block, im_stride, dst, dst_stride, w, h,
    915                               y_filter_8tap);
    916 }
    917 
    918 void vpx_convolve8_avg_neon_i8mm(const uint8_t *src, ptrdiff_t src_stride,
    919                                 uint8_t *dst, ptrdiff_t dst_stride,
    920                                 const InterpKernel *filter, int x0_q4,
    921                                 int x_step_q4, int y0_q4, int y_step_q4, int w,
    922                                 int h) {
    923  DECLARE_ALIGNED(32, uint8_t, im_block[64 * 71]);
    924  const int im_stride = 64;
    925 
    926  // Averaging convolution always uses an 8-tap filter.
    927  // Account for the vertical phase needing 3 lines prior and 4 lines post.
    928  const int im_height = h + SUBPEL_TAPS - 1;
    929  const ptrdiff_t offset = SUBPEL_TAPS / 2 - 1;
    930 
    931  assert(y_step_q4 == 16);
    932  assert(x_step_q4 == 16);
    933 
    934  const int8x8_t x_filter_8tap = vmovn_s16(vld1q_s16(filter[x0_q4]));
    935 
    936  convolve_8tap_2d_horiz_neon_i8mm(src - offset - offset * src_stride,
    937                                   src_stride, im_block, im_stride, w,
    938                                   im_height, x_filter_8tap);
    939 
    940  vpx_convolve8_avg_vert_neon_i8mm(im_block + offset * im_stride, im_stride,
    941                                   dst, dst_stride, filter, x0_q4, x_step_q4,
    942                                   y0_q4, y_step_q4, w, h);
    943 }