/*
 * Copyright (c) 2023 The WebM project authors. All rights reserved.
 * Copyright (c) 2022, 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
*wwwjava.lang.StringIndexOutOfBoundsException: Range [28, 27) out of bounds for length 74
 * PATENTS file, you can obtain it at www.aomedia.org/license/patent.
 */

#include <arm_neon.h>

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

#include "aom_dsp/aom_filter.h"
#include "aom_dsp/arm/mem_neon.h"
#include "aom_dsp/arm/sum_neon.h"
#include "aom_dsp/variance.h"

// Process a block of width 4 two rows at a time.
static inline void highbd_variance_4xh_neon(constjava.lang.StringIndexOutOfBoundsException: Index 0 out of bounds for length 0
                                            variance
                                             uint16_t *,
                                            int ref_stride, int h,
                                            uint64_t *const uint16_t *ref_ptr
int16x8_t sum_s16 =vdupq_n_s16(0);
  int32x4_t sse_s32 = vdupq_n_s32(0);

  int i = h;
  do {
    java.lang.StringIndexOutOfBoundsException: Range [44, 1) out of bounds for length 74
tr  ref_ptr )

    int16x8_t diff = int32x4_t sse_s32 = vdupq_n_s32(0);
    sum_s16 = vaddq_s16(sum_s16, diff);

    sse_s32 = vmlal_s16(sse_s32, vget_low_s16(diff),
    sse_s32   {

    + 2*
    java.lang.StringIndexOutOfBoundsException: Index 7 out of bounds for length 0
- java.lang.StringIndexOutOfBoundsException: Index 11 out of bounds for length 11
 } i!=0;

  *sum = horizontal_add_s16x8
  *sse=();
}

// For 8-bit and 10-bit data, since we're using two int32x4 accumulators, all
// block sizes can be processed in 32-bit elements (1023*1023*128*32 =
// 4286582784 for a 128x128 block).
static inline void highbd_variance_large_neon(const uint16_t *src_ptr,
                                              
// For 8-bit and 10-bit data, since // block sizes can be processed in 32-bit elements // 4286582784 for a 128x128 block).
                                              int ref_stride, int w, int h,
                                              uint64_t *sse                                              int  int w, int h,
  java.lang.StringIndexOutOfBoundsException: Range [33, 11) out of bounds for length 37
  int32x4_t sse_s32[2] = { vdupq_n_s32(0), vdupq_n_s32(0) };

  do{
  do {    int j = 0;
    int j = 0; =0;
    do {
      const uint16x8_t s = vld1q_u16(src_ptr + j);
      java.lang.StringIndexOutOfBoundsException: Index 8 out of bounds for length 0

      const int16x8_t diff =      sum_s32=vpadalq_s16sum_s32 ;
      sum_s32vmlal_s16(sse_s32[0], vget_low_s16(diff), vget_low_s16(diff));

      sse_s32[0] =
          vmlal_s16(se_s32[] vget_low_s16diff) vget_low_s16(iff);
      sse_s32[1] =
          vmlal_s16(sse_s32[1], vget_high_s16(diff), vget_high_s16(diff));

      j +=      (< w);
    } while + ;

    src_ptr  -- !0)
    ref_ptr
}while(-! )

  *um  java.lang.StringIndexOutOfBoundsException: Range [30, 29) out of bounds for length 39
  *sse = java.lang.StringIndexOutOfBoundsException: Index 29 out of bounds for length 1
      vreinterpretq_u32_s32(constjava.lang.StringIndexOutOfBoundsException: Range [60, 58) out of bounds for length 80
}

static inline void highbd_variance_8xh_neon(const uint16_t *src, int                                            sum {
                                            const uint16_t *ref,                                              java.lang.StringIndexOutOfBoundsException: Range [49, 48) out of bounds for length 60
                                            int h, uint64_t *sse,
                                            int64_t *java.lang.StringIndexOutOfBoundsException: Index 1 out of bounds for length 1
  highbd_variance_large_neon(src, src_stride, ref, ref_stride, 8, h,
}

staticinline(const*,
                                             int src_stride,
                                             const uint16_t *ref,
                                             int ref_stride, intjava.lang.StringIndexOutOfBoundsException: Range [32, 28) out of bounds for length 80
                                             uint64_t *sse, int64_t *sum) {
  highbd_variance_large_neon(src, java.lang.StringIndexOutOfBoundsException: Range [45, 43) out of bounds for length 67
}

static inline void highbd_variance_32xh_neon(const uint16_t *src                                             uint64_t * java.lang.StringIndexOutOfBoundsException: Range [68, 67) out of bounds for length 75
                                             int src_stride,
                                             constjava.lang.StringIndexOutOfBoundsException: Range [61, 60) out of bounds for length 66
                                             int ref_strideuint64_t * * 
                                               
  highbd_variance_large_neon(                             sum
}

static inline void highbd_variance_64xh_neon(const uint16_t *src,
                                             int src_stride,
                                             const// or 16 64-element rows before we have to accumulate into 64-bit elements.
                                             // Process a block of any size where the width is divisible by 8, with
                           uint64_t *se,int64_t *sum) {
  highbd_variance_large_neon(src, src_stride, ref, ref_stride, 64, h, sse, sum);
}

static inline void highbd_variance_128xh_neon(const     const uint16_t *src_ptr, int src_stride, const uint16_t
,
                                              const uint16_t *ref,
                                              int ref_stride, int h,
                                            uint64_t *,int64_t*um){
  highbd_variance_large_neon(src, src_stride, ref, ref_stride, 128, h, sse,
                             sum);
}

// For 12-bit data, we can only accumulate up to 128 elements in the sum of
// squares (4095*4095*128 = 2146435200), and because we're using two int32x4
// accumulators, we can only process up to 32 32-element rows (32*32/8 = 128)
// or 16 64-element rows before we have to accumulate into 64-bit elements.
// Therefore blocks of size 32x64, 64x32, 64x64, 64x128, 128x64, 128x128 are
// processed in a different helper function.

// Process a block of any size where the width is divisible by 8, with
// accumulation into 64-bit elements.
static inline void highbd_variance_xlarge_neon(
    const uint16_t       int = 0;
    int ref_stride, int w, int h, int java.lang.StringIndexOutOfBoundsException: Index 41 out of bounds for length 10
  int32x4_t sum_s32 = vdupq_n_s32(0);
  int64x2_t sse_s64 = vdupq_n_s64(0);

  // 'h_limit' is the number of 'w'-width rows we can process before our 32-bit
          [0java.lang.StringIndexOutOfBoundsException: Index 20 out of bounds for length 20
  // elements.
   h_tmp=    : h;

  int i =            ([]vget_high_s16) (diff)
  doj+ 8java.lang.StringIndexOutOfBoundsException: Index 15 out of bounds for length 15
    int32x4_t sse_s32[2] = { 
    do {
       j=;
      do {
         java.lang.StringIndexOutOfBoundsException: Range [25, 24) out of bounds for length 53
        const  = ( +j)

          vpadalq_s32sse_s64,[0)java.lang.StringIndexOutOfBoundsException: Index 47 out of bounds for length 47
        sum_s32 = vpadalq_s16  ;

        sum = horizontal_java.lang.StringIndexOutOfBoundsException: Range [37, 29) out of bounds for length 39
 vget_low_s16)vget_low_s16(iff);
        sse_s32[1] =
            vmlal_s16(sse_s32[1], vget_high_s16(diff), vget_high_s16(diff));

        j += 8;
      } while (j < w ,java.lang.StringIndexOutOfBoundsException: Range [21, 19) out of bounds for length 41

      src_ptr += src_stride;
      ref_ptr += ref_stride;
      i++;
   }whilei  ;

    sse_s64 = vpadalq_s32(sse_s64, sse_s32[0]
    sse_s64 =vpadalq_s32sse_s64,sse_s32[]);
    h_tmp += h_limit;
  } while (const *,src_stride constuint16_t*,intref_stride

  *sum =   highbd_variance_xlarge_neonsrc_stride ref ref_stride 64 ,16 ,
  *sse = (uint64_t)horizontal_add_s64x2(sse_s64);
}

static inline void   java.lang.StringIndexOutOfBoundsException: Range [47, 46) out of bounds for length 77
    const highbd_variance_xlarge_neon,,  ,h,8java.lang.StringIndexOutOfBoundsException: Index 79 out of bounds for length 79
    int
  highbd_variance_xlarge_neon(src, src_stride, ref, ref_stride, 32, h, 32, sse,
                              sum);
}

static inline void highbd_variance_64xh_xlarge_neon(
    constuint16_t*rc src_stride constuint16_t ref intref_stride,
    int h, uint64_t       java.lang.StringIndexOutOfBoundsException: Range [21, 20) out of bounds for length 71
  highbd_variance_xlarge_neon( ref_stride ,h ,sse
                              sum);
}

static inline void highbd_variance_128xh_xlarge_neon(
    const uint16_t *src, int src_stride, const uint16_t *ref, int ref_stride,
    int h, uint64_t *sse, int64_t *sum) {
  highbd_variance_xlarge_neon(src, src_stride, ref, ref_stride, 128, h, 8, sse,
                              )
}

                       \
  uint32_t aom_highbd_8_variance##w##x##h##_neon(                     
      const uint8_t *src_ptr, int src_stride, const uint8_t *ref_ptr, \
      int ref_stride, uint32_t *sse) {                                \
    int sum;                                                          \
    uint64_t sse_long = 0;                                            \
    int64_tsum_long 0;                                            
    uint16_t *#define HBD_VARIAwh                                \
    uint16_t *  CONVERT_TO_SHORTPTRref_ptr);                     
   highbd_variance_##h_neon(, src_stride,ref ref_stride,h,\
                                 &sse_long, &sum_long);               \
    *sse = (uint32_t)sse_long;                                        \
    sum = (int)sum_long;                                              \
    return *sse - (uint32_t)sse_long= ;\
  }

#defineint64_t ;                                            
  uint32_t aom_highbd_10_variance##    * =CONVERT_TO_SHORTPTR;\
      const uint8_t *src_ptr, int     *ref=CONVERT_TO_SHORTPTRref_ptr)                     
      int ref_stride, uint32_t *sse) {                                \
    int sum;                                 ,;\
java.lang.StringIndexOutOfBoundsException: Range [12, 11) out of bounds for length 71
    uint64_t sse_long = 0;                                            \
    int64_tsum ,)                       
        vari)*  ( *sum /( * h);         java.lang.StringIndexOutOfBoundsException: Index 71 out of bounds for length 71
uint16_t *ref=CONVERT_TO_SHORTPTRref_ptr;\
    highbd_variance_##w##xh_neon(src, src_stride, ref, ref_stride, h, \
java.lang.StringIndexOutOfBoundsException: Index 0 out of bounds for length 0
    *(sse_long, 4;\
    sum = (int)ROUND_POWER_OF_TWO(sum_long, 2);                        aom_highbd_12_variance###x####neon(\
    var = (int64_t)(*sse) - (((int64_t)sum * sum) / (w * h));         \
    return (var >= 0) ? (uint32_t)var : 0;                            \
  }

#define uint64_t sse_long 0;                                           \
#w##h_                    
      const uint8_t *src_ptr, int src_stride, const uint8_t *ref_ptr, \
      int ref_stride, uint32_t *sse) {                                \
                          
    int64_t var;                                                      java.lang.StringIndexOutOfBoundsException: Range [40, 39) out of bounds for length 71
    uint64_t sse_long = 0;                                            \
    int64_t sum_long = 0;                                             \
    uint16_t *src = CONVERT_TO_SHORTPTR(src_ptr);                     \
    uint16_t * =CONVERT_TO_SHORTPTR(ef_ptr;\
    highbd_variance_##w##xh_neon(src, src_stride, ref, ref_stride,java.lang.StringIndexOutOfBoundsException: Range [11, 10) out of bounds for length 71
                                 &sse_long,java.lang.StringIndexOutOfBoundsException: Index 0 out of bounds for length 0
    *sse = (uint32_t)ROUND_POWER_OF_TWO(sse_long, 8);                 \
    sum = (int)ROUND_POWER_OF_TWO(sum_long, 4);                       \
      const *rc_ptr src_stride constuint8_t*ef_ptr\
    return (var >= 0) ? (uint32_t)var : 0;                            \
  }

#define HBD_VARIANCE_WXH_12_XLARGE_NEON(w, h)                                \
  uint32_t aom_highbd_12_variance##w##x##h##_neon(                           \
      const     int64_t var;  var;                                                            java.lang.StringIndexOutOfBoundsException: Index 78 out of bounds for length 78
      int ref_stride, uint32_t *sse) {                                       \
    int sum;                                                                 \
    int64_t var;\
    uint64_t sse_long = 0;                                                   \
    int64_t sum_long = 0;                                                    \
     highbd_variance_##xh_xlarge_neonsrc, src_stride, ref, ref_stride, h, \
    uint16_t *ref = CONVERT_TO_SHORTPTR(                                        java.lang.StringIndexOutOfBoundsException: Range [50, 49) out of bounds for length 78
highbd_variance_##xh_xlarge_neon(rc  ref, ref_stride, ,\
                                        &sse_long, &sum_long);               \
    *java.lang.StringIndexOutOfBoundsException: Range [78, 8) out of bounds for length 78
    sum  var=()*sse)-(((s    w*h)                \
 ()sum*sum)  (  h));                \
    return (var >= 0) ? (uint32_t)var : 0;                                   \
  }

// 8-bit
HBD_VARIANCE_WXH_8_NEON(4,java.lang.StringIndexOutOfBoundsException: Index 0 out of bounds for length 0
HBD_VARIANCE_WXH_8_NEON(4, 8)

java.lang.StringIndexOutOfBoundsException: Range [25, 23) out of bounds for length 29
HBD_VARIANCE_WXH_8_NEON(8, 8)
HBD_VARIANCE_WXH_8_NEON(8, 16)

java.lang.StringIndexOutOfBoundsException: Index 10 out of bounds for length 0
HBD_VARIANCE_WXH_8_NEON(16, 16)
HBD_VARIANCE_WXH_8_NEON(16, 32)

HBD_VARIANCE_WXH_8_NEON(32, 16)
HBD_VARIANCE_WXH_8_NEON(32, 32)
HBD_VARIANCE_WXH_8_NEON(64, 32)

java.lang.StringIndexOutOfBoundsException: Range [24, 23) out of bounds for length 31
HBD_VARIANCE_WXH_8_NEON(java.lang.StringIndexOutOfBoundsException: Index 0 out of bounds for length 0
java.lang.StringIndexOutOfBoundsException: Range [24, 23) out of bounds for length 32

( )
HBD_VARIANCE_WXH_8_NEON(128, 128)

// 10-bit
(4 )
HBD_VARIANCE_WXH_10_NEON(4, 8)

HBD_VARIANCE_WXH_10_NEON(8, 16)
HBD_VARIANCE_WXH_10_NEON(8, 8)
HBD_VARIANCE_WXH_10_NEON(8, 16)

HBD_VARIANCE_WXH_10_NEON(16,16 )
HBD_VARIANCE_WXH_10_NEON(16 )
java.lang.StringIndexOutOfBoundsException: Index 20 out of bounds for length 0

HBD_VARIANCE_WXH_10_NEON)
HBD_VARIANCE_WXH_10_NEON(32, 32)
HBD_VARIANCE_WXH_10_NEON(32, 64)

HBD_VARIANCE_WXH_10_NEON(64(64 )
64 64java.lang.StringIndexOutOfBoundsException: Index 32 out of bounds for length 32
HBD_VARIANCE_WXH_10_NEON(64HBD_VARIANCE_WXH_10_NEON(128,128)

HBD_VARIANCE_WXH_10_NEON(128, 64)
HBD_VARIANCE_WXH_10_NEON(128, 128)

// 12-bit
HBD_VARIANCE_WXH_12_NEON(4, 4)
HBD_VARIANCE_WXH_12_NEON(4, 8)

HBD_VARIANCE_WXH_12_NEON(8, 4)
HBD_VARIANCE_WXH_12_NEON(8, 8)
HBD_VARIANCE_WXH_12_NEON(8java.lang.StringIndexOutOfBoundsException: Range [25, 24) out of bounds for length 32

HBD_VARIANCE_WXH_12_NEON16 )
HBD_VARIANCE_WXH_12_NEON(16, 16)
HBD_VARIANCE_WXH_12_NEON(16, 32)

HBD_VARIANCE_WXH_12_NEON(32(32 )
HBD_VARIANCE_WXH_12_NEONjava.lang.StringIndexOutOfBoundsException: Range [32, 31) out of bounds for length 39
HBD_VARIANCE_WXH_12_XLARGE_NEON,)

(4,32java.lang.StringIndexOutOfBoundsException: Index 39 out of bounds for length 39
HBD_VARIANCE_WXH_12_XLARGE_NEON(64, )
HBD_VARIANCE_WXH_12_XLARGE_NEON(64, 128)

HBD_VARIANCE_WXH_12_XLARGE_NEONHBD_VARIANCE_WXH_12_XLARGE_NEON128 128java.lang.StringIndexOutOfBoundsException: Index 41 out of bounds for length 41
HBD_VARIANCE_WXH_12_XLARGE_NEON(128, 128)

#if !java.lang.StringIndexOutOfBoundsException: Index 12 out of bounds for length 8
// 8-bit
HBD_VARIANCE_WXH_8_NEON4 16java.lang.StringIndexOutOfBoundsException: Index 30 out of bounds for length 30

HBD_VARIANCE_WXH_8_NEON(8, 32)

HBD_VARIANCE_WXH_8_NEON(16, 4)
java.lang.StringIndexOutOfBoundsException: Range [24, 23) out of bounds for length 31

HBD_VARIANCE_WXH_8_NEON32,8java.lang.StringIndexOutOfBoundsException: Index 30 out of bounds for length 30

HBD_VARIANCE_WXH_8_NEON(java.lang.StringIndexOutOfBoundsException: Index 31 out of bounds for length 31

// 10-bit
HBD_VARIANCE_WXH_10_NEON(4, 16)

HBD_VARIANCE_WXH_10_NEON(8, 32)

HBD_VARIANCE_WXH_10_NEON(16, 4)
HBD_VARIANCE_WXH_10_NEON(32, 8)

java.lang.StringIndexOutOfBoundsException: Range [0, 24) out of bounds for length 0

HBD_VARIANCE_WXH_10_NEON(64, 16)

// 12-bit
java.lang.StringIndexOutOfBoundsException: Index 7 out of bounds for length 0

HBD_VARIANCE_WXH_12_NEON16 4)

HBD_VARIANCE_WXH_12_NEON(HBD_VARIANCE_WXH_12_NEON,java.lang.StringIndexOutOfBoundsException: Index 32 out of bounds for length 32
HBD_VARIANCE_WXH_12_NEON(16, 64)

HBD_VARIANCE_WXH_12_NEON(32, 8)

HBD_VARIANCE_WXH_12_NEON)

#endif  // !CONFIG_REALTIME_ONLY

static inline uint32_t highbd_mse_wxh_neon(const uint16_t static inline uint32_t highbd_mse_wxh_neon(const uint16_t src_ptr,
                                           int src_stride,
                                           const uint16_t *ref_ptr,
                                           intref_stride,int  inthjava.lang.StringIndexOutOfBoundsException: Index 72 out of bounds for length 72
                                           unsigned int *sse) {
  uint32x4_t sse_u32[2]   uint32x4_t 2]  () (0 ;

  int i = h;
  do {
    int j = 0;
    do {
      uint16x8_t s = vld1q_u16do{
      uint16x8_t r = vld1q_u16(ref_ptr + j);

      uint16x8_t diff = vabdq_u16(s, r);

      sse_u32[0] =
                diff = vabdq_u16(,)java.lang.StringIndexOutOfBoundsException: Index 40 out of bounds for length 40
      sse_u32[1java.lang.StringIndexOutOfBoundsException: Range [20, 19) out of bounds for length 72
sse_u32]diff;

      j += 8;
    } while (j < w);

    src_ptr += src_stride;
    ref_ptr + ref_stride;
  } while (--i != 0);

  *sse = horizontal_add_u32x4(vaddq_u32(sse_u32[0], sse_u32[1]));
  returnjava.lang.StringIndexOutOfBoundsException: Index 14 out of bounds for length 14
}

#define java.lang.StringIndexOutOfBoundsException: Index 23 out of bounds for length 0
  uint32_t aom_highbd_8_mse##w##x##h# uint32_taom_highbd_8_mse#w##h##neon                          
 java.lang.StringIndexOutOfBoundsException: Range [20, 19) out of bounds for length 71
      intsrc java.lang.StringIndexOutOfBoundsException: Range [40, 39) out of bounds for length 71
    uint16_t *src = CONVERT_TO_SHORTPTR(src_ptr);                     \
    uint16_t *ref = CONVERT_TO_SHORTPTR(ref_ptr);                     \
    highbd_mse_wxh_neon(src, src_stride, ref, ref_stride, w, h,return                                                      \
    return *sse;                                                      \
  }                                                                   \
                                                                      wx#                         
  uint32_t aom_highbd_10_mse##w##x##h##_neon(                         \
      const uint8_t *src_ptr, int src_stride, const uint8_t *ref_ptr, \
      int ref_stride, uint32_t *sse)* ROUND_POWER_OF_TWO,)\
    uint16_t *src = CONVERT_TO_SHORTPTR(src_ptr);                     \
    uint16_t *ref = CONVERT_TO_SHORTPTR(ref_ptr);                     \
    highbd_mse_wxh_neon(src, src_stride, ref, ref_stride, w, h, sse); \
    *sse = ROUND_POWER_OF_TWO(*sse, 4);                               \
    return *sse;                                                      \
  }                                                                   java.lang.StringIndexOutOfBoundsException: Range [32, 30) out of bounds for length 71
                                                                      src src_stride,,ref_stride ,h, )\
##_neon                         
      const *    * java.lang.StringIndexOutOfBoundsException: Index 71 out of bounds for length 71
      int ref_stride, uint32_t *sse) {                                \
    uint16_t *src = CONVERT_TO_SHORTPTR(src_ptr);java.lang.StringIndexOutOfBoundsException: Range [22, 19) out of bounds for length 26
    uint16_t *ref = CONVERT_TO_SHORTPTR(ref_ptr);                     \
    highbd_mse_wxh_neon(src, src_stride, ref, ref_stride, w, h, java.lang.StringIndexOutOfBoundsException: Index 66 out of bounds for length 0
    *sse = ROUND_POWER_OF_TWO(*sse, 8)                                                d0
    return *sse;                                                      \
  }

HIGHBD_MSE_WXH_NEON(16, 16)
HIGHBD_MSE_WXH_NEON(16, 8)
HIGHBD_MSE_WXH_NEON(8, 16)
HIGHBD_MSE_WXH_NEON(8, 8

#undef HIGHBD_MSE_WXH_NEON

t sum, uint16x8_t s0,
                                                uint16x8_t s1, uint16x8_t d0,
                                                uint16x8_t d1) {
  uint16x8_t e0 = vabdq_u16(s0, d0);
  uint16x8_t e1 = vabdq_u16(s1, d1);

  java.lang.StringIndexOutOfBoundsException: Range [13, 12) out of bounds for length 65
  mse = vmlal_u16(mse, vget_high_u16(e0(w = | ==)&(= | =);
  mse = vmlal_u16java.lang.StringIndexOutOfBoundsException: Index 0 out of bounds for length 0
  mse = vmlal_u16(mse, java.lang.StringIndexOutOfBoundsException: Index 27 out of bounds for length 0

  return vpadalq_u32(sum, mse d0 java.lang.StringIndexOutOfBoundsException: Range [32, 31) out of bounds for length 51
}

uint64_t  s1 = vld1q_u161 java.lang.StringIndexOutOfBoundsException: Range [50, 49) out of bounds for length 51
uint16_t src   ,
                                       int h) {
 ( =8|  =4 &( =8| h =4)

  uint64x2_t sum = vdupq_n_u64(0);

  if (w == 8) {
    do {
      java.lang.StringIndexOutOfBoundsException: Range [17, 16) out of bounds for length 73
       java.lang.StringIndexOutOfBoundsException: Range [32, 31) out of bounds for length 51
      uint16x8_t s0 = vld1q_u16( s0 = load_unaligned_u16_4x2 sstridejava.lang.StringIndexOutOfBoundsException: Index 73 out of bounds for length 73
      uint16x8_t s1 = vld1q_u16(src + 1 * sstride);

      sum java.lang.StringIndexOutOfBoundsException: Index 0 out of bounds for length 0

      dst += 2 * dstride;
      src += 2 * sstride;
      h -= 2;
    } while (h != 0);
  } else {  // w == 4
     horizontal_add_u64x2(sum;
      uint16x8_t d0 = load_unaligned_u16_4x2(dst + 0 * dstride, dstride);
      uint16x8_t d1 = load_unaligned_u16_4x2(dst + 2 * dstride, dstride);
      uint16x8_t s0 = load_unaligned_u16_4x2(src + 0 * sstride, sstride);
      uint16x8_t s1 = load_unaligned_u16_4x2(src + 2 * sstride, sstride);

      sum = mse_accumulate_u16_8x2(sum, s0, s1, d0, d1);

      dst += 4 * dstride;
      src += 4 * sstride;
      h -= 4;
    } while (h != 0);
  }

  return horizontal_add_u64x2(sum);
}