/*
 * Copyright (c) 2017 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 "transforms/output.hpp"
#include "winograd_gemm.hpp"
#include "arm.hpp"

namespace winograd
{

using Transform = WinogradGEMM<4, 4, 3, 3>::OutputTransform<float>;

template <>
template <>
int Transform::ops_performed(const Tensor4DShape &shape)
{
  // NOTE: Cost in FLOPs rather than instructions or uops.
  const int tile_M = iceildiv(shape.n_rows, 4);
  const int tile_N = iceildiv(shape.n_cols, 4);
  return 170 * tile_M * tile_N * shape.n_channels;
}

// Instantiate cost methods
template int Transform::ops_performed(const Tensor4DShape&);

/* F(4x4, 3x3) constructs 4x4 output tiles from a 3x3 convolution. Since we use
 * enough tiles to cover the output space each output tile may contain up to 3
 * padded values to the right and bottom columns or rows of the tile, e.g.:
*
*      ________    ________   ________   ________
*     |       |   |      X|  |    X X|  |  X X X|
*     |       |   |      X|  |    X X|  |  X X X|
*     |       |   |      X|  |    X X|  |  X X X|
*     |_______|   |______X|  |____X_X|  |__X_X_X|
*
*      ________    ________   ________   ________
*     |       |   |      X|  |    X X|  |  X X X|
*     |       |   |      X|  |    X X|  |  X X X|
*     |       |   |      X|  |    X X|  |  X X X|
*     |X_X_X_X|   |X_X_X_X|  |X_X_X_X|  |X_X_X_X|
*
*      ________    ________   ________   ________
*     |       |   |      X|  |    X X|  |  X X X|
*     |       |   |      X|  |    X X|  |  X X X|
*     |X X X X|   |X X X X|  |X X X X|  |X X X X|
*     |X_X_X_X|   |X_X_X_X|  |X_X_X_X|  |X_X_X_X|
*
*      ________    ________   ________   ________
*     |       |   |      X|  |    X X|  |  X X X|
*     |X X X X|   |X X X X|  |X X X X|  |X X X X|
*     |X X X X|   |X X X X|  |X X X X|  |X X X X|
*     |X_X_X_X|   |X_X_X_X|  |X_X_X_X|  |X_X_X_X|
*
*
* We provide a specialised output transform for each of these instances.
*/
template <>
template <>
template <int pad_bottom, int pad_right>
void Transform::process_tile(
  const int n_channels,
  const float* const matrix_base,
  const int matrix_stride,
  float* const output,
  const int output_row_stride,
  const int output_col_stride
)
{
  constexpr int cells_i = 4 - pad_bottom;
  constexpr int cells_j = 4 - pad_right;

  // Construct a map to the output cells
  float *outptrs[cells_i][cells_j];
  for (int i = 0; i < cells_i; i++)
  {
    for (int j = 0; j < cells_j; j++)
    {
      outptrs[i][j] = output + i*output_row_stride + j*output_col_stride;
    }
  }
  const float *inptr = matrix_base;

  // For each channel of the output
  int channels_remaining = n_channels;
#ifdef __aarch64__
  for (; channels_remaining >= 4; channels_remaining -= 4)
  {
    // Matrices used and computed during this transform
    float32x4_t F[6][6], FZ[6][4], f[4][4];

    // Read a 6x6 tile in the Winograd domain
    for (int i = 0, m = 0; i < 6; i++)
    {
      for (int j = 0; j < 6; j++, m++)
      {
        F[i][j] = vld1q_f32(inptr + m*matrix_stride);
      }
    }
    inptr += 4;

    // Compute the matrix F Z
    for (int i = 0; i < 6; i++)
    {
      // FZ[i][0] =  1*F[i][0] +  1*F[i][1] +  1*F[i][2] +  1*F[i][3] +  1*F[i][4];
      FZ[i][0] = vaddq_f32(vaddq_f32(vaddq_f32(F[i][0], F[i][1]), vaddq_f32(F[i][2], F[i][3])), F[i][4]);

      // FZ[i][1] =  1*F[i][1] + -1*F[i][2] +  2*F[i][3] + -2*F[i][4];
      FZ[i][1] = vmlaq_n_f32(vsubq_f32(F[i][1], F[i][2]), vsubq_f32(F[i][3], F[i][4]), 2.0f);

      // FZ[i][2] =  1*F[i][1] +  1*F[i][2] +  4*F[i][3] +  4*F[i][4];
      FZ[i][2] = vmlaq_n_f32(vaddq_f32(F[i][1], F[i][2]), vaddq_f32(F[i][3], F[i][4]), 4.0f);

      // FZ[i][3] =  1*F[i][1] + -1*F[i][2] +  8*F[i][3] + -8*F[i][4] +  1*F[i][5];
      FZ[i][3] = vaddq_f32(vmlaq_n_f32(vsubq_f32(F[i][1], F[i][2]), vsubq_f32(F[i][3], F[i][4]), 8.0f), F[i][5]);
    }

    // Compute the output tile f = ZT F Z
    for (int j = 0; j < 4; j++)
    {
      // f[0][j] =  1*FZ[0][j] +  1*FZ[1][j] +  1*FZ[2][j] +  1*FZ[3][j] +  1*FZ[4][j];
      f[0][j] = vaddq_f32(vaddq_f32(vaddq_f32(FZ[0][j], FZ[1][j]), vaddq_f32(FZ[2][j], FZ[3][j])), FZ[4][j]);

      // f[1][j] =  1*FZ[1][j] + -1*FZ[2][j] +  2*FZ[3][j] + -2*FZ[4][j];
      f[1][j] = vmlaq_n_f32(vsubq_f32(FZ[1][j], FZ[2][j]), vsubq_f32(FZ[3][j], FZ[4][j]), 2.0f);

      // f[2][j] =  1*FZ[1][j] +  1*FZ[2][j] +  4*FZ[3][j] +  4*FZ[4][j];
      f[2][j] = vmlaq_n_f32(vaddq_f32(FZ[1][j], FZ[2][j]), vaddq_f32(FZ[3][j], FZ[4][j]), 4.0f);

      // f[3][j] =  1*FZ[1][j] + -1*FZ[2][j] +  8*FZ[3][j] + -8*FZ[4][j] +  1*FZ[5][j];
      f[3][j] = vaddq_f32(vmlaq_n_f32(vsubq_f32(FZ[1][j], FZ[2][j]), vsubq_f32(FZ[3][j], FZ[4][j]), 8.0f), FZ[5][j]);
    }

    // Write out the output tile
    for (int i = 0; i < cells_i; i++)
    {
      for (int j = 0; j < cells_j; j++)
      {
        vst1q_f32(outptrs[i][j], f[i][j]);
        outptrs[i][j] += 4;
      }
    }
  }
#endif  // __aarch64__
#ifdef __arm_any__
  for (; channels_remaining >= 2; channels_remaining -= 2)
  {
    // Matrices used and computed during this transform
    float32x2_t F[6][6], FZ[6][4], f[4][4];

    // Read a 6x6 tile in the Winograd domain
    for (int i = 0, m = 0; i < 6; i++)
    {
      for (int j = 0; j < 6; j++, m++)
      {
        F[i][j] = vld1_f32(inptr + m*matrix_stride);
      }
    }
    inptr += 2;

    // Compute the matrix F Z
    for (int i = 0; i < 6; i++)
    {
      // FZ[i][0] =  1*F[i][0] +  1*F[i][1] +  1*F[i][2] +  1*F[i][3] +  1*F[i][4];
      FZ[i][0] = vadd_f32(vadd_f32(vadd_f32(F[i][0], F[i][1]), vadd_f32(F[i][2], F[i][3])), F[i][4]);

      // FZ[i][1] =  1*F[i][1] + -1*F[i][2] +  2*F[i][3] + -2*F[i][4];
      FZ[i][1] = vmla_n_f32(vsub_f32(F[i][1], F[i][2]), vsub_f32(F[i][3], F[i][4]), 2.0f);

      // FZ[i][2] =  1*F[i][1] +  1*F[i][2] +  4*F[i][3] +  4*F[i][4];
      FZ[i][2] = vmla_n_f32(vadd_f32(F[i][1], F[i][2]), vadd_f32(F[i][3], F[i][4]), 4.0f);

      // FZ[i][3] =  1*F[i][1] + -1*F[i][2] +  8*F[i][3] + -8*F[i][4] +  1*F[i][5];
      FZ[i][3] = vadd_f32(vmla_n_f32(vsub_f32(F[i][1], F[i][2]), vsub_f32(F[i][3], F[i][4]), 8.0f), F[i][5]);
    }

    // Compute the output tile f = ZT F Z
    for (int j = 0; j < 4; j++)
    {
      // f[0][j] =  1*FZ[0][j] +  1*FZ[1][j] +  1*FZ[2][j] +  1*FZ[3][j] +  1*FZ[4][j];
      f[0][j] = vadd_f32(vadd_f32(vadd_f32(FZ[0][j], FZ[1][j]), vadd_f32(FZ[2][j], FZ[3][j])), FZ[4][j]);

      // f[1][j] =  1*FZ[1][j] + -1*FZ[2][j] +  2*FZ[3][j] + -2*FZ[4][j];
      f[1][j] = vmla_n_f32(vsub_f32(FZ[1][j], FZ[2][j]), vsub_f32(FZ[3][j], FZ[4][j]), 2.0f);

      // f[2][j] =  1*FZ[1][j] +  1*FZ[2][j] +  4*FZ[3][j] +  4*FZ[4][j];
      f[2][j] = vmla_n_f32(vadd_f32(FZ[1][j], FZ[2][j]), vadd_f32(FZ[3][j], FZ[4][j]), 4.0f);

      // f[3][j] =  1*FZ[1][j] + -1*FZ[2][j] +  8*FZ[3][j] + -8*FZ[4][j] +  1*FZ[5][j];
      f[3][j] = vadd_f32(vmla_n_f32(vsub_f32(FZ[1][j], FZ[2][j]), vsub_f32(FZ[3][j], FZ[4][j]), 8.0f), FZ[5][j]);
    }

    // Write out the output tile
    for (int i = 0; i < cells_i; i++)
    {
      for (int j = 0; j < cells_j; j++)
      {
        vst1_f32(outptrs[i][j], f[i][j]);
        outptrs[i][j] += 2;
      }
    }
  }
#endif
  for (; channels_remaining; channels_remaining--)
  {
    // Matrices used and computed during this transform
    float F[6][6], FZ[6][4], f[4][4];

    // Read a 6x6 tile in the Winograd domain
    for (int i = 0, m = 0; i < 6; i++)
    {
      for (int j = 0; j < 6; j++, m++)
      {
        F[i][j] = *(inptr + m*matrix_stride);
      }
    }
    inptr++;

    // Compute the matrix F Z
    for (int i = 0; i < 6; i++)
    {
      FZ[i][0] =  1*F[i][0] +  1*F[i][1] +  1*F[i][2] +  1*F[i][3] +  1*F[i][4];
      FZ[i][1] =  1*F[i][1] + -1*F[i][2] +  2*F[i][3] + -2*F[i][4];
      FZ[i][2] =  1*F[i][1] +  1*F[i][2] +  4*F[i][3] +  4*F[i][4];
      FZ[i][3] =  1*F[i][1] + -1*F[i][2] +  8*F[i][3] + -8*F[i][4] +  1*F[i][5];
    }

    // Compute the output tile f = ZT F Z
    for (int j = 0; j < 4; j++)
    {
      f[0][j] =  1*FZ[0][j] +  1*FZ[1][j] +  1*FZ[2][j] +  1*FZ[3][j] +  1*FZ[4][j];
      f[1][j] =  1*FZ[1][j] + -1*FZ[2][j] +  2*FZ[3][j] + -2*FZ[4][j];
      f[2][j] =  1*FZ[1][j] +  1*FZ[2][j] +  4*FZ[3][j] +  4*FZ[4][j];
      f[3][j] =  1*FZ[1][j] + -1*FZ[2][j] +  8*FZ[3][j] + -8*FZ[4][j] +  1*FZ[5][j];
    }

    // Write out the output tile
    for (int i = 0; i < cells_i; i++)
    {
      for (int j = 0; j < cells_j; j++)
      {
        *(outptrs[i][j]++) = f[i][j];
      }
    }
  }
}

template <>
template <>
const Transform::TileFn Transform::tile_fns[max_pad_bottom][max_pad_right] =
{
  {
    Transform::template process_tile<0, 0>,
    Transform::template process_tile<0, 1>,
    Transform::template process_tile<0, 2>,
    Transform::template process_tile<0, 3>,
  },
  {
    Transform::template process_tile<1, 0>,
    Transform::template process_tile<1, 1>,
    Transform::template process_tile<1, 2>,
    Transform::template process_tile<1, 3>,
  },
  {
    Transform::template process_tile<2, 0>,
    Transform::template process_tile<2, 1>,
    Transform::template process_tile<2, 2>,
    Transform::template process_tile<2, 3>,
  },
  {
    Transform::template process_tile<3, 0>,
    Transform::template process_tile<3, 1>,
    Transform::template process_tile<3, 2>,
    Transform::template process_tile<3, 3>,
  }
};

template struct WinogradGEMM<4, 4, 3, 3>::OutputTransform<float>;
}  // namespace winograd