/*
 * Copyright (c) 2017, 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
 * Media Patent License 1.0 was not distributed with this source code in the
 * PATENTS file, you can obtain it at www.aomedia.org/license/patent.
 */

#include <emmintrin.h>

#include "./av1_rtcd.h"
#include "av1/common/warped_motion.h"

void av1_warp_affine_sse2(const int32_t *mat, const uint8_t *ref, int width,
                          int height, int stride, uint8_t *pred, int p_col,
                          int p_row, int p_width, int p_height, int p_stride,
                          int subsampling_x, int subsampling_y,
                          ConvolveParams *conv_params, int16_t alpha,
                          int16_t beta, int16_t gamma, int16_t delta) {
  int comp_avg = conv_params->do_average;
  __m128i tmp[15];
  int i, j, k;
  const int bd = 8;

  /* Note: For this code to work, the left/right frame borders need to be
     extended by at least 13 pixels each. By the time we get here, other
     code will have set up this border, but we allow an explicit check
     for debugging purposes.
  */
  /*for (i = 0; i < height; ++i) {
    for (j = 0; j < 13; ++j) {
      assert(ref[i * stride - 13 + j] == ref[i * stride]);
      assert(ref[i * stride + width + j] == ref[i * stride + (width - 1)]);
    }
  }*/

  for (i = 0; i < p_height; i += 8) {
    for (j = 0; j < p_width; j += 8) {
      // (x, y) coordinates of the center of this block in the destination
      // image
      const int32_t dst_x = p_col + j + 4;
      const int32_t dst_y = p_row + i + 4;

      int32_t x4, y4, ix4, sx4, iy4, sy4;
      if (subsampling_x)
        x4 = (mat[2] * 4 * dst_x + mat[3] * 4 * dst_y + mat[0] * 2 +
              (mat[2] + mat[3] - (1 << WARPEDMODEL_PREC_BITS))) /
             4;
      else
        x4 = mat[2] * dst_x + mat[3] * dst_y + mat[0];

      if (subsampling_y)
        y4 = (mat[4] * 4 * dst_x + mat[5] * 4 * dst_y + mat[1] * 2 +
              (mat[4] + mat[5] - (1 << WARPEDMODEL_PREC_BITS))) /
             4;
      else
        y4 = mat[4] * dst_x + mat[5] * dst_y + mat[1];

      ix4 = x4 >> WARPEDMODEL_PREC_BITS;
      sx4 = x4 & ((1 << WARPEDMODEL_PREC_BITS) - 1);
      iy4 = y4 >> WARPEDMODEL_PREC_BITS;
      sy4 = y4 & ((1 << WARPEDMODEL_PREC_BITS) - 1);

      // Add in all the constant terms, including rounding and offset
      sx4 += alpha * (-4) + beta * (-4) + (1 << (WARPEDDIFF_PREC_BITS - 1)) +
             (WARPEDPIXEL_PREC_SHIFTS << WARPEDDIFF_PREC_BITS);
      sy4 += gamma * (-4) + delta * (-4) + (1 << (WARPEDDIFF_PREC_BITS - 1)) +
             (WARPEDPIXEL_PREC_SHIFTS << WARPEDDIFF_PREC_BITS);

      sx4 &= ~((1 << WARP_PARAM_REDUCE_BITS) - 1);
      sy4 &= ~((1 << WARP_PARAM_REDUCE_BITS) - 1);

      // Horizontal filter
      // If the block is aligned such that, after clamping, every sample
      // would be taken from the leftmost/rightmost column, then we can
      // skip the expensive horizontal filter.
      if (ix4 <= -7) {
        for (k = -7; k < AOMMIN(8, p_height - i); ++k) {
          int iy = iy4 + k;
          if (iy < 0)
            iy = 0;
          else if (iy > height - 1)
            iy = height - 1;
          tmp[k + 7] = _mm_set1_epi16(
              (1 << (bd + WARPEDPIXEL_FILTER_BITS - HORSHEAR_REDUCE_PREC_BITS -
                     1)) +
              ref[iy * stride] *
                  (1 << (WARPEDPIXEL_FILTER_BITS - HORSHEAR_REDUCE_PREC_BITS)));
        }
      } else if (ix4 >= width + 6) {
        for (k = -7; k < AOMMIN(8, p_height - i); ++k) {
          int iy = iy4 + k;
          if (iy < 0)
            iy = 0;
          else if (iy > height - 1)
            iy = height - 1;
          tmp[k + 7] = _mm_set1_epi16(
              (1 << (bd + WARPEDPIXEL_FILTER_BITS - HORSHEAR_REDUCE_PREC_BITS -
                     1)) +
              ref[iy * stride + (width - 1)] *
                  (1 << (WARPEDPIXEL_FILTER_BITS - HORSHEAR_REDUCE_PREC_BITS)));
        }
      } else {
        for (k = -7; k < AOMMIN(8, p_height - i); ++k) {
          int iy = iy4 + k;
          if (iy < 0)
            iy = 0;
          else if (iy > height - 1)
            iy = height - 1;
          int sx = sx4 + beta * (k + 4);

          // Load source pixels
          const __m128i zero = _mm_setzero_si128();
          const __m128i src =
              _mm_loadu_si128((__m128i *)(ref + iy * stride + ix4 - 7));

          // Filter even-index pixels
          const __m128i tmp_0 = _mm_loadu_si128(
              (__m128i *)(warped_filter +
                          ((sx + 0 * alpha) >> WARPEDDIFF_PREC_BITS)));
          const __m128i tmp_2 = _mm_loadu_si128(
              (__m128i *)(warped_filter +
                          ((sx + 2 * alpha) >> WARPEDDIFF_PREC_BITS)));
          const __m128i tmp_4 = _mm_loadu_si128(
              (__m128i *)(warped_filter +
                          ((sx + 4 * alpha) >> WARPEDDIFF_PREC_BITS)));
          const __m128i tmp_6 = _mm_loadu_si128(
              (__m128i *)(warped_filter +
                          ((sx + 6 * alpha) >> WARPEDDIFF_PREC_BITS)));

          // coeffs 0 1 0 1 2 3 2 3 for pixels 0, 2
          const __m128i tmp_8 = _mm_unpacklo_epi32(tmp_0, tmp_2);
          // coeffs 0 1 0 1 2 3 2 3 for pixels 4, 6
          const __m128i tmp_10 = _mm_unpacklo_epi32(tmp_4, tmp_6);
          // coeffs 4 5 4 5 6 7 6 7 for pixels 0, 2
          const __m128i tmp_12 = _mm_unpackhi_epi32(tmp_0, tmp_2);
          // coeffs 4 5 4 5 6 7 6 7 for pixels 4, 6
          const __m128i tmp_14 = _mm_unpackhi_epi32(tmp_4, tmp_6);

          // coeffs 0 1 0 1 0 1 0 1 for pixels 0, 2, 4, 6
          const __m128i coeff_0 = _mm_unpacklo_epi64(tmp_8, tmp_10);
          // coeffs 2 3 2 3 2 3 2 3 for pixels 0, 2, 4, 6
          const __m128i coeff_2 = _mm_unpackhi_epi64(tmp_8, tmp_10);
          // coeffs 4 5 4 5 4 5 4 5 for pixels 0, 2, 4, 6
          const __m128i coeff_4 = _mm_unpacklo_epi64(tmp_12, tmp_14);
          // coeffs 6 7 6 7 6 7 6 7 for pixels 0, 2, 4, 6
          const __m128i coeff_6 = _mm_unpackhi_epi64(tmp_12, tmp_14);

          const __m128i round_const =
              _mm_set1_epi32((1 << (bd + WARPEDPIXEL_FILTER_BITS - 1)) +
                             ((1 << HORSHEAR_REDUCE_PREC_BITS) >> 1));

          // Calculate filtered results
          const __m128i src_0 = _mm_unpacklo_epi8(src, zero);
          const __m128i res_0 = _mm_madd_epi16(src_0, coeff_0);
          const __m128i src_2 = _mm_unpacklo_epi8(_mm_srli_si128(src, 2), zero);
          const __m128i res_2 = _mm_madd_epi16(src_2, coeff_2);
          const __m128i src_4 = _mm_unpacklo_epi8(_mm_srli_si128(src, 4), zero);
          const __m128i res_4 = _mm_madd_epi16(src_4, coeff_4);
          const __m128i src_6 = _mm_unpacklo_epi8(_mm_srli_si128(src, 6), zero);
          const __m128i res_6 = _mm_madd_epi16(src_6, coeff_6);

          __m128i res_even = _mm_add_epi32(_mm_add_epi32(res_0, res_4),
                                           _mm_add_epi32(res_2, res_6));
          res_even = _mm_srai_epi32(_mm_add_epi32(res_even, round_const),
                                    HORSHEAR_REDUCE_PREC_BITS);

          // Filter odd-index pixels
          const __m128i tmp_1 = _mm_loadu_si128(
              (__m128i *)(warped_filter +
                          ((sx + 1 * alpha) >> WARPEDDIFF_PREC_BITS)));
          const __m128i tmp_3 = _mm_loadu_si128(
              (__m128i *)(warped_filter +
                          ((sx + 3 * alpha) >> WARPEDDIFF_PREC_BITS)));
          const __m128i tmp_5 = _mm_loadu_si128(
              (__m128i *)(warped_filter +
                          ((sx + 5 * alpha) >> WARPEDDIFF_PREC_BITS)));
          const __m128i tmp_7 = _mm_loadu_si128(
              (__m128i *)(warped_filter +
                          ((sx + 7 * alpha) >> WARPEDDIFF_PREC_BITS)));

          const __m128i tmp_9 = _mm_unpacklo_epi32(tmp_1, tmp_3);
          const __m128i tmp_11 = _mm_unpacklo_epi32(tmp_5, tmp_7);
          const __m128i tmp_13 = _mm_unpackhi_epi32(tmp_1, tmp_3);
          const __m128i tmp_15 = _mm_unpackhi_epi32(tmp_5, tmp_7);

          const __m128i coeff_1 = _mm_unpacklo_epi64(tmp_9, tmp_11);
          const __m128i coeff_3 = _mm_unpackhi_epi64(tmp_9, tmp_11);
          const __m128i coeff_5 = _mm_unpacklo_epi64(tmp_13, tmp_15);
          const __m128i coeff_7 = _mm_unpackhi_epi64(tmp_13, tmp_15);

          const __m128i src_1 = _mm_unpacklo_epi8(_mm_srli_si128(src, 1), zero);
          const __m128i res_1 = _mm_madd_epi16(src_1, coeff_1);
          const __m128i src_3 = _mm_unpacklo_epi8(_mm_srli_si128(src, 3), zero);
          const __m128i res_3 = _mm_madd_epi16(src_3, coeff_3);
          const __m128i src_5 = _mm_unpacklo_epi8(_mm_srli_si128(src, 5), zero);
          const __m128i res_5 = _mm_madd_epi16(src_5, coeff_5);
          const __m128i src_7 = _mm_unpacklo_epi8(_mm_srli_si128(src, 7), zero);
          const __m128i res_7 = _mm_madd_epi16(src_7, coeff_7);

          __m128i res_odd = _mm_add_epi32(_mm_add_epi32(res_1, res_5),
                                          _mm_add_epi32(res_3, res_7));
          res_odd = _mm_srai_epi32(_mm_add_epi32(res_odd, round_const),
                                   HORSHEAR_REDUCE_PREC_BITS);

          // Combine results into one register.
          // We store the columns in the order 0, 2, 4, 6, 1, 3, 5, 7
          // as this order helps with the vertical filter.
          tmp[k + 7] = _mm_packs_epi32(res_even, res_odd);
        }
      }

      // Vertical filter
      for (k = -4; k < AOMMIN(4, p_height - i - 4); ++k) {
        int sy = sy4 + delta * (k + 4);

        // Load from tmp and rearrange pairs of consecutive rows into the
        // column order 0 0 2 2 4 4 6 6; 1 1 3 3 5 5 7 7
        const __m128i *src = tmp + (k + 4);
        const __m128i src_0 = _mm_unpacklo_epi16(src[0], src[1]);
        const __m128i src_2 = _mm_unpacklo_epi16(src[2], src[3]);
        const __m128i src_4 = _mm_unpacklo_epi16(src[4], src[5]);
        const __m128i src_6 = _mm_unpacklo_epi16(src[6], src[7]);

        // Filter even-index pixels
        const __m128i tmp_0 = _mm_loadu_si128(
            (__m128i *)(warped_filter +
                        ((sy + 0 * gamma) >> WARPEDDIFF_PREC_BITS)));
        const __m128i tmp_2 = _mm_loadu_si128(
            (__m128i *)(warped_filter +
                        ((sy + 2 * gamma) >> WARPEDDIFF_PREC_BITS)));
        const __m128i tmp_4 = _mm_loadu_si128(
            (__m128i *)(warped_filter +
                        ((sy + 4 * gamma) >> WARPEDDIFF_PREC_BITS)));
        const __m128i tmp_6 = _mm_loadu_si128(
            (__m128i *)(warped_filter +
                        ((sy + 6 * gamma) >> WARPEDDIFF_PREC_BITS)));

        const __m128i tmp_8 = _mm_unpacklo_epi32(tmp_0, tmp_2);
        const __m128i tmp_10 = _mm_unpacklo_epi32(tmp_4, tmp_6);
        const __m128i tmp_12 = _mm_unpackhi_epi32(tmp_0, tmp_2);
        const __m128i tmp_14 = _mm_unpackhi_epi32(tmp_4, tmp_6);

        const __m128i coeff_0 = _mm_unpacklo_epi64(tmp_8, tmp_10);
        const __m128i coeff_2 = _mm_unpackhi_epi64(tmp_8, tmp_10);
        const __m128i coeff_4 = _mm_unpacklo_epi64(tmp_12, tmp_14);
        const __m128i coeff_6 = _mm_unpackhi_epi64(tmp_12, tmp_14);

        const __m128i res_0 = _mm_madd_epi16(src_0, coeff_0);
        const __m128i res_2 = _mm_madd_epi16(src_2, coeff_2);
        const __m128i res_4 = _mm_madd_epi16(src_4, coeff_4);
        const __m128i res_6 = _mm_madd_epi16(src_6, coeff_6);

        const __m128i res_even = _mm_add_epi32(_mm_add_epi32(res_0, res_2),
                                               _mm_add_epi32(res_4, res_6));

        // Filter odd-index pixels
        const __m128i src_1 = _mm_unpackhi_epi16(src[0], src[1]);
        const __m128i src_3 = _mm_unpackhi_epi16(src[2], src[3]);
        const __m128i src_5 = _mm_unpackhi_epi16(src[4], src[5]);
        const __m128i src_7 = _mm_unpackhi_epi16(src[6], src[7]);

        const __m128i tmp_1 = _mm_loadu_si128(
            (__m128i *)(warped_filter +
                        ((sy + 1 * gamma) >> WARPEDDIFF_PREC_BITS)));
        const __m128i tmp_3 = _mm_loadu_si128(
            (__m128i *)(warped_filter +
                        ((sy + 3 * gamma) >> WARPEDDIFF_PREC_BITS)));
        const __m128i tmp_5 = _mm_loadu_si128(
            (__m128i *)(warped_filter +
                        ((sy + 5 * gamma) >> WARPEDDIFF_PREC_BITS)));
        const __m128i tmp_7 = _mm_loadu_si128(
            (__m128i *)(warped_filter +
                        ((sy + 7 * gamma) >> WARPEDDIFF_PREC_BITS)));

        const __m128i tmp_9 = _mm_unpacklo_epi32(tmp_1, tmp_3);
        const __m128i tmp_11 = _mm_unpacklo_epi32(tmp_5, tmp_7);
        const __m128i tmp_13 = _mm_unpackhi_epi32(tmp_1, tmp_3);
        const __m128i tmp_15 = _mm_unpackhi_epi32(tmp_5, tmp_7);

        const __m128i coeff_1 = _mm_unpacklo_epi64(tmp_9, tmp_11);
        const __m128i coeff_3 = _mm_unpackhi_epi64(tmp_9, tmp_11);
        const __m128i coeff_5 = _mm_unpacklo_epi64(tmp_13, tmp_15);
        const __m128i coeff_7 = _mm_unpackhi_epi64(tmp_13, tmp_15);

        const __m128i res_1 = _mm_madd_epi16(src_1, coeff_1);
        const __m128i res_3 = _mm_madd_epi16(src_3, coeff_3);
        const __m128i res_5 = _mm_madd_epi16(src_5, coeff_5);
        const __m128i res_7 = _mm_madd_epi16(src_7, coeff_7);

        const __m128i res_odd = _mm_add_epi32(_mm_add_epi32(res_1, res_3),
                                              _mm_add_epi32(res_5, res_7));

        // Rearrange pixels back into the order 0 ... 7
        const __m128i res_lo = _mm_unpacklo_epi32(res_even, res_odd);
        const __m128i res_hi = _mm_unpackhi_epi32(res_even, res_odd);

        // Round and pack into 8 bits
        const __m128i round_const =
            _mm_set1_epi32(-(1 << (bd + VERSHEAR_REDUCE_PREC_BITS - 1)) +
                           ((1 << VERSHEAR_REDUCE_PREC_BITS) >> 1));

        const __m128i res_lo_round = _mm_srai_epi32(
            _mm_add_epi32(res_lo, round_const), VERSHEAR_REDUCE_PREC_BITS);
        const __m128i res_hi_round = _mm_srai_epi32(
            _mm_add_epi32(res_hi, round_const), VERSHEAR_REDUCE_PREC_BITS);

        const __m128i res_16bit = _mm_packs_epi32(res_lo_round, res_hi_round);
        __m128i res_8bit = _mm_packus_epi16(res_16bit, res_16bit);

        // Store, blending with 'pred' if needed
        __m128i *const p = (__m128i *)&pred[(i + k + 4) * p_stride + j];

        // Note: If we're outputting a 4x4 block, we need to be very careful
        // to only output 4 pixels at this point, to avoid encode/decode
        // mismatches when encoding with multiple threads.
        if (p_width == 4) {
          if (comp_avg) {
            const __m128i orig = _mm_cvtsi32_si128(*(uint32_t *)p);
            res_8bit = _mm_avg_epu8(res_8bit, orig);
          }
          *(uint32_t *)p = _mm_cvtsi128_si32(res_8bit);
        } else {
          if (comp_avg) res_8bit = _mm_avg_epu8(res_8bit, _mm_loadl_epi64(p));
          _mm_storel_epi64(p, res_8bit);
        }
      }
    }
  }
}