/*
 * Copyright (c) 2019 Arm Limited.
 *
 * SPDX-License-Identifier: MIT
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to
 * deal in the Software without restriction, including without limitation the
 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
 * sell copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#include "arm.hpp"
#include "kernel.hpp"

namespace winograd
{

template <>
void WeightTransform<3, 3, 4, 4, float, float, WinogradRoots::Integers>::execute(
  const int n_output_channels,
  const int n_input_channels,
  const float* const input,
  float* const output,
  const int matrix_stride,
  const int matrix_row_stride
)
{
  constexpr int inner_tile_i = 4;
  constexpr int inner_tile_j = 4;

  // Get pointers to each cell of the weight tensor
  const auto weight_col_stride = n_input_channels * n_output_channels;
  const auto weight_row_stride = 3 * weight_col_stride;
  const float *inptrs[3][3];
  for (int i = 0; i < 3; i++)
  {
    for (int j = 0; j < 3; j++)
    {
      inptrs[i][j] = input + i*weight_row_stride + j*weight_col_stride;
    }
  }

  // For each input channel
  for (int ic = 0; ic < n_input_channels; ic++)
  {
    float *outptr = output + ic * matrix_row_stride;

    // For each output channel
    int channels_remaining = n_output_channels;
#ifdef __aarch64__
    for (; channels_remaining >= 4; channels_remaining -= 4)
    {
      // Matrices used and computed in this kernel
      float32x4_t w[3][3], Ww[inner_tile_i][3], V[inner_tile_i][inner_tile_j];

      // Read weights
      for (int i = 0; i < 3; i++)
      {
        for (int j = 0; j < 3; j++)
        {
          w[i][j] = vld1q_f32(inptrs[i][j]);
          inptrs[i][j] += 4;
        }
      }

      // Compute the matrix W w
      for (int j = 0; j < 3; j++)
      {
        Ww[0][j] = w[0][j];

        // Ww[1][j] = 0.5*(w[0][j] + w[1][j] + w[2][j]);
        Ww[1][j] = vmulq_n_f32(vaddq_f32(vaddq_f32(w[0][j], w[1][j]), w[2][j]), 0.5f);

        // Ww[2][j] = 0.5*(w[0][j] - w[1][j] + w[2][j]);
        Ww[2][j] = vmulq_n_f32(vaddq_f32(vsubq_f32(w[0][j], w[1][j]), w[2][j]), 0.5f);

        Ww[3][j] = w[2][j];
      }

      // Compute V = W w WT
      for (int i = 0; i < inner_tile_i; i++)
      {
        V[i][0] = Ww[i][0];

        // V[i][1] = 0.5*(Ww[i][0] + Ww[i][1] + Ww[i][2]);
        V[i][1] = vmulq_n_f32(vaddq_f32(vaddq_f32(Ww[i][0], Ww[i][1]), Ww[i][2]), 0.5f);

        // V[i][2] = 0.5*(Ww[i][0] - Ww[i][1] + Ww[i][2]);
        V[i][2] = vmulq_n_f32(vaddq_f32(vsubq_f32(Ww[i][0], Ww[i][1]), Ww[i][2]), 0.5f);

        V[i][3] = Ww[i][2];
      }

      // Store the transformed weights
      for (int i = 0, m = 0; i < inner_tile_i; i++)
      {
        for (int j = 0; j < inner_tile_j; j++, m++)
        {
          vst1q_f32(outptr + m*matrix_stride, V[i][j]);
        }
      }
      outptr += 4;
    }
#endif  // __aarch64__
#ifdef __arm_any__
    for (; channels_remaining >= 2; channels_remaining -= 2)
    {
      // Matrices used and computed in this kernel
      float32x2_t w[3][3], Ww[inner_tile_i][3], V[inner_tile_i][inner_tile_j];

      // Read weights
      for (int i = 0; i < 3; i++)
      {
        for (int j = 0; j < 3; j++)
        {
          w[i][j] = vld1_f32(inptrs[i][j]);
          inptrs[i][j] += 2;
        }
      }

      // Compute the matrix W w
      for (int j = 0; j < 3; j++)
      {
        Ww[0][j] = w[0][j];

        // Ww[1][j] = 0.5*(w[0][j] + w[1][j] + w[2][j]);
        Ww[1][j] = vmul_n_f32(vadd_f32(vadd_f32(w[0][j], w[1][j]), w[2][j]), 0.5f);

        // Ww[2][j] = 0.5*(w[0][j] - w[1][j] + w[2][j]);
        Ww[2][j] = vmul_n_f32(vadd_f32(vsub_f32(w[0][j], w[1][j]), w[2][j]), 0.5f);

        Ww[3][j] = w[2][j];
      }

      // Compute V = W w WT
      for (int i = 0; i < inner_tile_i; i++)
      {
        V[i][0] = Ww[i][0];

        // V[i][1] = 0.5*(Ww[i][0] + Ww[i][1] + Ww[i][2]);
        V[i][1] = vmul_n_f32(vadd_f32(vadd_f32(Ww[i][0], Ww[i][1]), Ww[i][2]), 0.5f);

        // V[i][2] = 0.5*(Ww[i][0] - Ww[i][1] + Ww[i][2]);
        V[i][2] = vmul_n_f32(vadd_f32(vsub_f32(Ww[i][0], Ww[i][1]), Ww[i][2]), 0.5f);

        V[i][3] = Ww[i][2];
      }

      // Store the transformed weights
      for (int i = 0, m = 0; i < inner_tile_i; i++)
      {
        for (int j = 0; j < inner_tile_j; j++, m++)
        {
          vst1_f32(outptr + m*matrix_stride, V[i][j]);
        }
      }
      outptr += 2;
    }
#endif  // __arm_any__
    for (; channels_remaining; channels_remaining--)
    {
      // Matrices used and computed in this kernel
      float w[3][3], Ww[inner_tile_i][3], V[inner_tile_i][inner_tile_j];

      // Read weights
      for (int i = 0; i < 3; i++)
      {
        for (int j = 0; j < 3; j++)
        {
          w[i][j] = *(inptrs[i][j]++);
        }
      }

      // Compute the matrix W w
      for (int j = 0; j < 3; j++)
      {
        Ww[0][j] = w[0][j];
        Ww[1][j] = 0.5*(w[0][j] + w[1][j] + w[2][j]);
        Ww[2][j] = 0.5*(w[0][j] - w[1][j] + w[2][j]);
        Ww[3][j] = w[2][j];
      }

      // Compute V = W w WT
      for (int i = 0; i < inner_tile_i; i++)
      {
        V[i][0] = Ww[i][0];
        V[i][1] = 0.5*(Ww[i][0] + Ww[i][1] + Ww[i][2]);
        V[i][2] = 0.5*(Ww[i][0] - Ww[i][1] + Ww[i][2]);
        V[i][3] = Ww[i][2];
      }

      // Store the transformed weights
      for (int i = 0, m = 0; i < inner_tile_i; i++)
      {
        for (int j = 0; j < inner_tile_j; j++, m++)
        {
          *(outptr + m*matrix_stride) = V[i][j];
        }
      }
      outptr++;
    }
  }
}

template class WeightTransform<3, 3, 4, 4, float, float, WinogradRoots::Integers>;

}  // namespace
