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sum_squares_neon.c (18419B)


      1 /*
      2 * Copyright (c) 2020, Alliance for Open Media. All rights reserved.
      3 *
      4 * This source code is subject to the terms of the BSD 2 Clause License and
      5 * the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
      6 * was not distributed with this source code in the LICENSE file, you can
      7 * obtain it at www.aomedia.org/license/software. If the Alliance for Open
      8 * Media Patent License 1.0 was not distributed with this source code in the
      9 * PATENTS file, you can obtain it at www.aomedia.org/license/patent.
     10 */
     11 
     12 #include <arm_neon.h>
     13 #include <assert.h>
     14 
     15 #include "aom_dsp/arm/mem_neon.h"
     16 #include "aom_dsp/arm/sum_neon.h"
     17 #include "config/aom_config.h"
     18 #include "config/aom_dsp_rtcd.h"
     19 
     20 static inline uint64_t aom_sum_squares_2d_i16_4x4_neon(const int16_t *src,
     21                                                       int stride) {
     22  int16x4_t s0 = vld1_s16(src + 0 * stride);
     23  int16x4_t s1 = vld1_s16(src + 1 * stride);
     24  int16x4_t s2 = vld1_s16(src + 2 * stride);
     25  int16x4_t s3 = vld1_s16(src + 3 * stride);
     26 
     27  int32x4_t sum_squares = vmull_s16(s0, s0);
     28  sum_squares = vmlal_s16(sum_squares, s1, s1);
     29  sum_squares = vmlal_s16(sum_squares, s2, s2);
     30  sum_squares = vmlal_s16(sum_squares, s3, s3);
     31 
     32  return horizontal_long_add_u32x4(vreinterpretq_u32_s32(sum_squares));
     33 }
     34 
     35 static inline uint64_t aom_sum_squares_2d_i16_4xn_neon(const int16_t *src,
     36                                                       int stride, int height) {
     37  int32x4_t sum_squares[2] = { vdupq_n_s32(0), vdupq_n_s32(0) };
     38 
     39  int h = height;
     40  do {
     41    int16x4_t s0 = vld1_s16(src + 0 * stride);
     42    int16x4_t s1 = vld1_s16(src + 1 * stride);
     43    int16x4_t s2 = vld1_s16(src + 2 * stride);
     44    int16x4_t s3 = vld1_s16(src + 3 * stride);
     45 
     46    sum_squares[0] = vmlal_s16(sum_squares[0], s0, s0);
     47    sum_squares[0] = vmlal_s16(sum_squares[0], s1, s1);
     48    sum_squares[1] = vmlal_s16(sum_squares[1], s2, s2);
     49    sum_squares[1] = vmlal_s16(sum_squares[1], s3, s3);
     50 
     51    src += 4 * stride;
     52    h -= 4;
     53  } while (h != 0);
     54 
     55  return horizontal_long_add_u32x4(
     56      vreinterpretq_u32_s32(vaddq_s32(sum_squares[0], sum_squares[1])));
     57 }
     58 
     59 static inline uint64_t aom_sum_squares_2d_i16_nxn_neon(const int16_t *src,
     60                                                       int stride, int width,
     61                                                       int height) {
     62  uint64x2_t sum_squares = vdupq_n_u64(0);
     63 
     64  int h = height;
     65  do {
     66    int32x4_t ss_row[2] = { vdupq_n_s32(0), vdupq_n_s32(0) };
     67    int w = 0;
     68    do {
     69      const int16_t *s = src + w;
     70      int16x8_t s0 = vld1q_s16(s + 0 * stride);
     71      int16x8_t s1 = vld1q_s16(s + 1 * stride);
     72      int16x8_t s2 = vld1q_s16(s + 2 * stride);
     73      int16x8_t s3 = vld1q_s16(s + 3 * stride);
     74 
     75      ss_row[0] = vmlal_s16(ss_row[0], vget_low_s16(s0), vget_low_s16(s0));
     76      ss_row[0] = vmlal_s16(ss_row[0], vget_low_s16(s1), vget_low_s16(s1));
     77      ss_row[0] = vmlal_s16(ss_row[0], vget_low_s16(s2), vget_low_s16(s2));
     78      ss_row[0] = vmlal_s16(ss_row[0], vget_low_s16(s3), vget_low_s16(s3));
     79      ss_row[1] = vmlal_s16(ss_row[1], vget_high_s16(s0), vget_high_s16(s0));
     80      ss_row[1] = vmlal_s16(ss_row[1], vget_high_s16(s1), vget_high_s16(s1));
     81      ss_row[1] = vmlal_s16(ss_row[1], vget_high_s16(s2), vget_high_s16(s2));
     82      ss_row[1] = vmlal_s16(ss_row[1], vget_high_s16(s3), vget_high_s16(s3));
     83      w += 8;
     84    } while (w < width);
     85 
     86    sum_squares = vpadalq_u32(
     87        sum_squares, vreinterpretq_u32_s32(vaddq_s32(ss_row[0], ss_row[1])));
     88 
     89    src += 4 * stride;
     90    h -= 4;
     91  } while (h != 0);
     92 
     93  return horizontal_add_u64x2(sum_squares);
     94 }
     95 
     96 uint64_t aom_sum_squares_2d_i16_neon(const int16_t *src, int stride, int width,
     97                                     int height) {
     98  // 4 elements per row only requires half an SIMD register, so this
     99  // must be a special case, but also note that over 75% of all calls
    100  // are with size == 4, so it is also the common case.
    101  if (LIKELY(width == 4 && height == 4)) {
    102    return aom_sum_squares_2d_i16_4x4_neon(src, stride);
    103  } else if (LIKELY(width == 4 && (height & 3) == 0)) {
    104    return aom_sum_squares_2d_i16_4xn_neon(src, stride, height);
    105  } else if (LIKELY((width & 7) == 0 && (height & 3) == 0)) {
    106    // Generic case
    107    return aom_sum_squares_2d_i16_nxn_neon(src, stride, width, height);
    108  } else {
    109    return aom_sum_squares_2d_i16_c(src, stride, width, height);
    110  }
    111 }
    112 
    113 static inline uint64_t aom_sum_sse_2d_i16_4x4_neon(const int16_t *src,
    114                                                   int stride, int *sum) {
    115  int16x4_t s0 = vld1_s16(src + 0 * stride);
    116  int16x4_t s1 = vld1_s16(src + 1 * stride);
    117  int16x4_t s2 = vld1_s16(src + 2 * stride);
    118  int16x4_t s3 = vld1_s16(src + 3 * stride);
    119 
    120  int32x4_t sse = vmull_s16(s0, s0);
    121  sse = vmlal_s16(sse, s1, s1);
    122  sse = vmlal_s16(sse, s2, s2);
    123  sse = vmlal_s16(sse, s3, s3);
    124 
    125  int32x4_t sum_01 = vaddl_s16(s0, s1);
    126  int32x4_t sum_23 = vaddl_s16(s2, s3);
    127  *sum += horizontal_add_s32x4(vaddq_s32(sum_01, sum_23));
    128 
    129  return horizontal_long_add_u32x4(vreinterpretq_u32_s32(sse));
    130 }
    131 
    132 static inline uint64_t aom_sum_sse_2d_i16_4xn_neon(const int16_t *src,
    133                                                   int stride, int height,
    134                                                   int *sum) {
    135  int32x4_t sse[2] = { vdupq_n_s32(0), vdupq_n_s32(0) };
    136  int32x2_t sum_acc[2] = { vdup_n_s32(0), vdup_n_s32(0) };
    137 
    138  int h = height;
    139  do {
    140    int16x4_t s0 = vld1_s16(src + 0 * stride);
    141    int16x4_t s1 = vld1_s16(src + 1 * stride);
    142    int16x4_t s2 = vld1_s16(src + 2 * stride);
    143    int16x4_t s3 = vld1_s16(src + 3 * stride);
    144 
    145    sse[0] = vmlal_s16(sse[0], s0, s0);
    146    sse[0] = vmlal_s16(sse[0], s1, s1);
    147    sse[1] = vmlal_s16(sse[1], s2, s2);
    148    sse[1] = vmlal_s16(sse[1], s3, s3);
    149 
    150    sum_acc[0] = vpadal_s16(sum_acc[0], s0);
    151    sum_acc[0] = vpadal_s16(sum_acc[0], s1);
    152    sum_acc[1] = vpadal_s16(sum_acc[1], s2);
    153    sum_acc[1] = vpadal_s16(sum_acc[1], s3);
    154 
    155    src += 4 * stride;
    156    h -= 4;
    157  } while (h != 0);
    158 
    159  *sum += horizontal_add_s32x4(vcombine_s32(sum_acc[0], sum_acc[1]));
    160  return horizontal_long_add_u32x4(
    161      vreinterpretq_u32_s32(vaddq_s32(sse[0], sse[1])));
    162 }
    163 
    164 static inline uint64_t aom_sum_sse_2d_i16_nxn_neon(const int16_t *src,
    165                                                   int stride, int width,
    166                                                   int height, int *sum) {
    167  uint64x2_t sse = vdupq_n_u64(0);
    168  int32x4_t sum_acc = vdupq_n_s32(0);
    169 
    170  int h = height;
    171  do {
    172    int32x4_t sse_row[2] = { vdupq_n_s32(0), vdupq_n_s32(0) };
    173    int w = 0;
    174    do {
    175      const int16_t *s = src + w;
    176      int16x8_t s0 = vld1q_s16(s + 0 * stride);
    177      int16x8_t s1 = vld1q_s16(s + 1 * stride);
    178      int16x8_t s2 = vld1q_s16(s + 2 * stride);
    179      int16x8_t s3 = vld1q_s16(s + 3 * stride);
    180 
    181      sse_row[0] = vmlal_s16(sse_row[0], vget_low_s16(s0), vget_low_s16(s0));
    182      sse_row[0] = vmlal_s16(sse_row[0], vget_low_s16(s1), vget_low_s16(s1));
    183      sse_row[0] = vmlal_s16(sse_row[0], vget_low_s16(s2), vget_low_s16(s2));
    184      sse_row[0] = vmlal_s16(sse_row[0], vget_low_s16(s3), vget_low_s16(s3));
    185      sse_row[1] = vmlal_s16(sse_row[1], vget_high_s16(s0), vget_high_s16(s0));
    186      sse_row[1] = vmlal_s16(sse_row[1], vget_high_s16(s1), vget_high_s16(s1));
    187      sse_row[1] = vmlal_s16(sse_row[1], vget_high_s16(s2), vget_high_s16(s2));
    188      sse_row[1] = vmlal_s16(sse_row[1], vget_high_s16(s3), vget_high_s16(s3));
    189 
    190      sum_acc = vpadalq_s16(sum_acc, s0);
    191      sum_acc = vpadalq_s16(sum_acc, s1);
    192      sum_acc = vpadalq_s16(sum_acc, s2);
    193      sum_acc = vpadalq_s16(sum_acc, s3);
    194 
    195      w += 8;
    196    } while (w < width);
    197 
    198    sse = vpadalq_u32(sse,
    199                      vreinterpretq_u32_s32(vaddq_s32(sse_row[0], sse_row[1])));
    200 
    201    src += 4 * stride;
    202    h -= 4;
    203  } while (h != 0);
    204 
    205  *sum += horizontal_add_s32x4(sum_acc);
    206  return horizontal_add_u64x2(sse);
    207 }
    208 
    209 uint64_t aom_sum_sse_2d_i16_neon(const int16_t *src, int stride, int width,
    210                                 int height, int *sum) {
    211  uint64_t sse;
    212 
    213  if (LIKELY(width == 4 && height == 4)) {
    214    sse = aom_sum_sse_2d_i16_4x4_neon(src, stride, sum);
    215  } else if (LIKELY(width == 4 && (height & 3) == 0)) {
    216    // width = 4, height is a multiple of 4.
    217    sse = aom_sum_sse_2d_i16_4xn_neon(src, stride, height, sum);
    218  } else if (LIKELY((width & 7) == 0 && (height & 3) == 0)) {
    219    // Generic case - width is multiple of 8, height is multiple of 4.
    220    sse = aom_sum_sse_2d_i16_nxn_neon(src, stride, width, height, sum);
    221  } else {
    222    sse = aom_sum_sse_2d_i16_c(src, stride, width, height, sum);
    223  }
    224 
    225  return sse;
    226 }
    227 
    228 static inline uint64_t aom_sum_squares_i16_4xn_neon(const int16_t *src,
    229                                                    uint32_t n) {
    230  uint64x2_t sum_u64 = vdupq_n_u64(0);
    231 
    232  int i = n;
    233  do {
    234    uint32x4_t sum;
    235    int16x4_t s0 = vld1_s16(src);
    236 
    237    sum = vreinterpretq_u32_s32(vmull_s16(s0, s0));
    238 
    239    sum_u64 = vpadalq_u32(sum_u64, sum);
    240 
    241    src += 4;
    242    i -= 4;
    243  } while (i >= 4);
    244 
    245  if (i > 0) {
    246    return horizontal_add_u64x2(sum_u64) + aom_sum_squares_i16_c(src, i);
    247  }
    248  return horizontal_add_u64x2(sum_u64);
    249 }
    250 
    251 static inline uint64_t aom_sum_squares_i16_8xn_neon(const int16_t *src,
    252                                                    uint32_t n) {
    253  uint64x2_t sum_u64[2] = { vdupq_n_u64(0), vdupq_n_u64(0) };
    254 
    255  int i = n;
    256  do {
    257    uint32x4_t sum[2];
    258    int16x8_t s0 = vld1q_s16(src);
    259 
    260    sum[0] =
    261        vreinterpretq_u32_s32(vmull_s16(vget_low_s16(s0), vget_low_s16(s0)));
    262    sum[1] =
    263        vreinterpretq_u32_s32(vmull_s16(vget_high_s16(s0), vget_high_s16(s0)));
    264 
    265    sum_u64[0] = vpadalq_u32(sum_u64[0], sum[0]);
    266    sum_u64[1] = vpadalq_u32(sum_u64[1], sum[1]);
    267 
    268    src += 8;
    269    i -= 8;
    270  } while (i >= 8);
    271 
    272  if (i > 0) {
    273    return horizontal_add_u64x2(vaddq_u64(sum_u64[0], sum_u64[1])) +
    274           aom_sum_squares_i16_c(src, i);
    275  }
    276  return horizontal_add_u64x2(vaddq_u64(sum_u64[0], sum_u64[1]));
    277 }
    278 
    279 uint64_t aom_sum_squares_i16_neon(const int16_t *src, uint32_t n) {
    280  // This function seems to be called only for values of N >= 64. See
    281  // av1/encoder/compound_type.c.
    282  if (LIKELY(n >= 8)) {
    283    return aom_sum_squares_i16_8xn_neon(src, n);
    284  }
    285  if (n >= 4) {
    286    return aom_sum_squares_i16_4xn_neon(src, n);
    287  }
    288  return aom_sum_squares_i16_c(src, n);
    289 }
    290 
    291 static inline uint64_t aom_var_2d_u8_4xh_neon(uint8_t *src, int src_stride,
    292                                              int width, int height) {
    293  uint64_t sum = 0;
    294  uint64_t sse = 0;
    295  uint32x2_t sum_u32 = vdup_n_u32(0);
    296  uint32x4_t sse_u32 = vdupq_n_u32(0);
    297 
    298  // 255*256 = 65280, so we can accumulate up to 256 8-bit elements in a 16-bit
    299  // element before we need to accumulate to 32-bit elements. Since we're
    300  // accumulating in uint16x4_t vectors, this means we can accumulate up to 4
    301  // rows of 256 elements. Therefore the limit can be computed as: h_limit = (4
    302  // * 256) / width.
    303  int h_limit = (4 * 256) / width;
    304  int h_tmp = height > h_limit ? h_limit : height;
    305 
    306  int h = 0;
    307  do {
    308    uint16x4_t sum_u16 = vdup_n_u16(0);
    309    do {
    310      uint8_t *src_ptr = src;
    311      int w = width;
    312      do {
    313        uint8x8_t s0 = load_unaligned_u8(src_ptr, src_stride);
    314 
    315        sum_u16 = vpadal_u8(sum_u16, s0);
    316 
    317        uint16x8_t sse_u16 = vmull_u8(s0, s0);
    318 
    319        sse_u32 = vpadalq_u16(sse_u32, sse_u16);
    320 
    321        src_ptr += 8;
    322        w -= 8;
    323      } while (w >= 8);
    324 
    325      // Process remaining columns in the row using C.
    326      while (w > 0) {
    327        int idx = width - w;
    328        const uint8_t v = src[idx];
    329        sum += v;
    330        sse += v * v;
    331        w--;
    332      }
    333 
    334      src += 2 * src_stride;
    335      h += 2;
    336    } while (h < h_tmp && h < height);
    337 
    338    sum_u32 = vpadal_u16(sum_u32, sum_u16);
    339    h_tmp += h_limit;
    340  } while (h < height);
    341 
    342  sum += horizontal_long_add_u32x2(sum_u32);
    343  sse += horizontal_long_add_u32x4(sse_u32);
    344 
    345  return sse - sum * sum / (width * height);
    346 }
    347 
    348 static inline uint64_t aom_var_2d_u8_8xh_neon(uint8_t *src, int src_stride,
    349                                              int width, int height) {
    350  uint64_t sum = 0;
    351  uint64_t sse = 0;
    352  uint32x2_t sum_u32 = vdup_n_u32(0);
    353  uint32x4_t sse_u32 = vdupq_n_u32(0);
    354 
    355  // 255*256 = 65280, so we can accumulate up to 256 8-bit elements in a 16-bit
    356  // element before we need to accumulate to 32-bit elements. Since we're
    357  // accumulating in uint16x4_t vectors, this means we can accumulate up to 4
    358  // rows of 256 elements. Therefore the limit can be computed as: h_limit = (4
    359  // * 256) / width.
    360  int h_limit = (4 * 256) / width;
    361  int h_tmp = height > h_limit ? h_limit : height;
    362 
    363  int h = 0;
    364  do {
    365    uint16x4_t sum_u16 = vdup_n_u16(0);
    366    do {
    367      uint8_t *src_ptr = src;
    368      int w = width;
    369      do {
    370        uint8x8_t s0 = vld1_u8(src_ptr);
    371 
    372        sum_u16 = vpadal_u8(sum_u16, s0);
    373 
    374        uint16x8_t sse_u16 = vmull_u8(s0, s0);
    375 
    376        sse_u32 = vpadalq_u16(sse_u32, sse_u16);
    377 
    378        src_ptr += 8;
    379        w -= 8;
    380      } while (w >= 8);
    381 
    382      // Process remaining columns in the row using C.
    383      while (w > 0) {
    384        int idx = width - w;
    385        const uint8_t v = src[idx];
    386        sum += v;
    387        sse += v * v;
    388        w--;
    389      }
    390 
    391      src += src_stride;
    392      ++h;
    393    } while (h < h_tmp && h < height);
    394 
    395    sum_u32 = vpadal_u16(sum_u32, sum_u16);
    396    h_tmp += h_limit;
    397  } while (h < height);
    398 
    399  sum += horizontal_long_add_u32x2(sum_u32);
    400  sse += horizontal_long_add_u32x4(sse_u32);
    401 
    402  return sse - sum * sum / (width * height);
    403 }
    404 
    405 static inline uint64_t aom_var_2d_u8_16xh_neon(uint8_t *src, int src_stride,
    406                                               int width, int height) {
    407  uint64_t sum = 0;
    408  uint64_t sse = 0;
    409  uint32x4_t sum_u32 = vdupq_n_u32(0);
    410  uint32x4_t sse_u32[2] = { vdupq_n_u32(0), vdupq_n_u32(0) };
    411 
    412  // 255*256 = 65280, so we can accumulate up to 256 8-bit elements in a 16-bit
    413  // element before we need to accumulate to 32-bit elements. Since we're
    414  // accumulating in uint16x8_t vectors, this means we can accumulate up to 8
    415  // rows of 256 elements. Therefore the limit can be computed as: h_limit = (8
    416  // * 256) / width.
    417  int h_limit = (8 * 256) / width;
    418  int h_tmp = height > h_limit ? h_limit : height;
    419 
    420  int h = 0;
    421  do {
    422    uint16x8_t sum_u16 = vdupq_n_u16(0);
    423    do {
    424      int w = width;
    425      uint8_t *src_ptr = src;
    426      do {
    427        uint8x16_t s0 = vld1q_u8(src_ptr);
    428 
    429        sum_u16 = vpadalq_u8(sum_u16, s0);
    430 
    431        uint16x8_t sse_u16_lo = vmull_u8(vget_low_u8(s0), vget_low_u8(s0));
    432        uint16x8_t sse_u16_hi = vmull_u8(vget_high_u8(s0), vget_high_u8(s0));
    433 
    434        sse_u32[0] = vpadalq_u16(sse_u32[0], sse_u16_lo);
    435        sse_u32[1] = vpadalq_u16(sse_u32[1], sse_u16_hi);
    436 
    437        src_ptr += 16;
    438        w -= 16;
    439      } while (w >= 16);
    440 
    441      // Process remaining columns in the row using C.
    442      while (w > 0) {
    443        int idx = width - w;
    444        const uint8_t v = src[idx];
    445        sum += v;
    446        sse += v * v;
    447        w--;
    448      }
    449 
    450      src += src_stride;
    451      ++h;
    452    } while (h < h_tmp && h < height);
    453 
    454    sum_u32 = vpadalq_u16(sum_u32, sum_u16);
    455    h_tmp += h_limit;
    456  } while (h < height);
    457 
    458  sum += horizontal_long_add_u32x4(sum_u32);
    459  sse += horizontal_long_add_u32x4(vaddq_u32(sse_u32[0], sse_u32[1]));
    460 
    461  return sse - sum * sum / (width * height);
    462 }
    463 
    464 uint64_t aom_var_2d_u8_neon(uint8_t *src, int src_stride, int width,
    465                            int height) {
    466  if (width >= 16) {
    467    return aom_var_2d_u8_16xh_neon(src, src_stride, width, height);
    468  }
    469  if (width >= 8) {
    470    return aom_var_2d_u8_8xh_neon(src, src_stride, width, height);
    471  }
    472  if (width >= 4 && height % 2 == 0) {
    473    return aom_var_2d_u8_4xh_neon(src, src_stride, width, height);
    474  }
    475  return aom_var_2d_u8_c(src, src_stride, width, height);
    476 }
    477 
    478 #if CONFIG_AV1_HIGHBITDEPTH
    479 static inline uint64_t aom_var_2d_u16_4xh_neon(uint8_t *src, int src_stride,
    480                                               int width, int height) {
    481  uint16_t *src_u16 = CONVERT_TO_SHORTPTR(src);
    482  uint64_t sum = 0;
    483  uint64_t sse = 0;
    484  uint32x2_t sum_u32 = vdup_n_u32(0);
    485  uint64x2_t sse_u64 = vdupq_n_u64(0);
    486 
    487  int h = height;
    488  do {
    489    int w = width;
    490    uint16_t *src_ptr = src_u16;
    491    do {
    492      uint16x4_t s0 = vld1_u16(src_ptr);
    493 
    494      sum_u32 = vpadal_u16(sum_u32, s0);
    495 
    496      uint32x4_t sse_u32 = vmull_u16(s0, s0);
    497 
    498      sse_u64 = vpadalq_u32(sse_u64, sse_u32);
    499 
    500      src_ptr += 4;
    501      w -= 4;
    502    } while (w >= 4);
    503 
    504    // Process remaining columns in the row using C.
    505    while (w > 0) {
    506      int idx = width - w;
    507      const uint16_t v = src_u16[idx];
    508      sum += v;
    509      sse += v * v;
    510      w--;
    511    }
    512 
    513    src_u16 += src_stride;
    514  } while (--h != 0);
    515 
    516  sum += horizontal_long_add_u32x2(sum_u32);
    517  sse += horizontal_add_u64x2(sse_u64);
    518 
    519  return sse - sum * sum / (width * height);
    520 }
    521 
    522 static inline uint64_t aom_var_2d_u16_8xh_neon(uint8_t *src, int src_stride,
    523                                               int width, int height) {
    524  uint16_t *src_u16 = CONVERT_TO_SHORTPTR(src);
    525  uint64_t sum = 0;
    526  uint64_t sse = 0;
    527  uint32x4_t sum_u32 = vdupq_n_u32(0);
    528  uint64x2_t sse_u64[2] = { vdupq_n_u64(0), vdupq_n_u64(0) };
    529 
    530  int h = height;
    531  do {
    532    int w = width;
    533    uint16_t *src_ptr = src_u16;
    534    do {
    535      uint16x8_t s0 = vld1q_u16(src_ptr);
    536 
    537      sum_u32 = vpadalq_u16(sum_u32, s0);
    538 
    539      uint32x4_t sse_u32_lo = vmull_u16(vget_low_u16(s0), vget_low_u16(s0));
    540      uint32x4_t sse_u32_hi = vmull_u16(vget_high_u16(s0), vget_high_u16(s0));
    541 
    542      sse_u64[0] = vpadalq_u32(sse_u64[0], sse_u32_lo);
    543      sse_u64[1] = vpadalq_u32(sse_u64[1], sse_u32_hi);
    544 
    545      src_ptr += 8;
    546      w -= 8;
    547    } while (w >= 8);
    548 
    549    // Process remaining columns in the row using C.
    550    while (w > 0) {
    551      int idx = width - w;
    552      const uint16_t v = src_u16[idx];
    553      sum += v;
    554      sse += v * v;
    555      w--;
    556    }
    557 
    558    src_u16 += src_stride;
    559  } while (--h != 0);
    560 
    561  sum += horizontal_long_add_u32x4(sum_u32);
    562  sse += horizontal_add_u64x2(vaddq_u64(sse_u64[0], sse_u64[1]));
    563 
    564  return sse - sum * sum / (width * height);
    565 }
    566 
    567 uint64_t aom_var_2d_u16_neon(uint8_t *src, int src_stride, int width,
    568                             int height) {
    569  if (width >= 8) {
    570    return aom_var_2d_u16_8xh_neon(src, src_stride, width, height);
    571  }
    572  if (width >= 4) {
    573    return aom_var_2d_u16_4xh_neon(src, src_stride, width, height);
    574  }
    575  return aom_var_2d_u16_c(src, src_stride, width, height);
    576 }
    577 #endif  // CONFIG_AV1_HIGHBITDEPTH