/* -----------------------------------------------------------------------------
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the Software are granted under this license.

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     this list of conditions and the following disclaimer.

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     software without specific prior written permission.

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------------------------------------------------------------------------------------------- */

/** \file     sum_neon.h
    \brief    Helper functions for adding across vectors
*/

#pragma once

#include "CommonDef.h"

#if defined( TARGET_SIMD_ARM )

#include <arm_neon.h>

namespace vvenc
{

static inline int horizontal_add_s32x4( const int32x4_t a )
{
#if REAL_TARGET_AARCH64
  return vaddvq_s32( a );
#else
  const int64x2_t b = vpaddlq_s32( a );
  const int32x2_t c = vadd_s32( vreinterpret_s32_s64( vget_low_s64( b ) ), vreinterpret_s32_s64( vget_high_s64( b ) ) );
  return vget_lane_s32( c, 0 );
#endif
}

static inline int horizontal_add_long_s16x8( const int16x8_t a )
{
#if REAL_TARGET_AARCH64
  return vaddlvq_s16( a );
#else
  return horizontal_add_s32x4( vpaddlq_s16( a ) );
#endif
}

static inline int32x4_t horizontal_add_4d_s32x4( const int32x4_t v0, const int32x4_t v1, const int32x4_t v2,
                                                 const int32x4_t v3 )
{
#if REAL_TARGET_AARCH64
  int32x4_t v01 = vpaddq_s32( v0, v1 );
  int32x4_t v23 = vpaddq_s32( v2, v3 );
  return vpaddq_s32( v01, v23 );
#else
  int32x4_t res = vdupq_n_s32( 0 );
  res           = vsetq_lane_s32( horizontal_add_s32x4( v0 ), res, 0 );
  res           = vsetq_lane_s32( horizontal_add_s32x4( v1 ), res, 1 );
  res           = vsetq_lane_s32( horizontal_add_s32x4( v2 ), res, 2 );
  res           = vsetq_lane_s32( horizontal_add_s32x4( v3 ), res, 3 );
  return res;
#endif
}

static inline int32x4_t horizontal_add_long_4d_s16x8( const int16x8_t v0, const int16x8_t v1, const int16x8_t v2,
                                                      const int16x8_t v3 )
{
  return horizontal_add_4d_s32x4( vpaddlq_s16( v0 ), vpaddlq_s16( v1 ), vpaddlq_s16( v2 ), vpaddlq_s16( v3 ) );
}

static inline int16x8_t pairwise_add_s16x8( const int16x8_t a, const int16x8_t b )
{
#if REAL_TARGET_AARCH64
  return vpaddq_s16( a, b );
#else
  int16x4_t lo = vpadd_s16( vget_low_s16( a ), vget_low_s16( b ) );
  int16x4_t hi = vpadd_s16( vget_high_s16( a ), vget_high_s16( b ) );
  return vcombine_s16( lo, hi );
#endif
}

static inline int32x4_t pairwise_add_s32x4( const int32x4_t a, const int32x4_t b )
{
#if REAL_TARGET_AARCH64
  return vpaddq_s32( a, b );
#else
  int32x2_t lo = vpadd_s32( vget_low_s32( a ), vget_low_s32( b ) );
  int32x2_t hi = vpadd_s32( vget_high_s32( a ), vget_high_s32( b ) );
  return vcombine_s32( lo, hi );
#endif
}

}  // namespace vvenc

#endif
