/*
 * Copyright (c) 2016, 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 <arm_neon.h>

void aom_idct4x4_16_add_neon(int16_t *input, uint8_t *dest, int dest_stride) {
  uint8x8_t d26u8, d27u8;
  uint32x2_t d26u32, d27u32;
  uint16x8_t q8u16, q9u16;
  int16x4_t d16s16, d17s16, d18s16, d19s16, d20s16, d21s16;
  int16x4_t d22s16, d23s16, d24s16, d26s16, d27s16, d28s16, d29s16;
  int16x8_t q8s16, q9s16, q13s16, q14s16;
  int32x4_t q1s32, q13s32, q14s32, q15s32;
  int16x4x2_t d0x2s16, d1x2s16;
  int32x4x2_t q0x2s32;
  uint8_t *d;
  int16_t cospi_8_64 = 15137;
  int16_t cospi_16_64 = 11585;
  int16_t cospi_24_64 = 6270;

  d26u32 = d27u32 = vdup_n_u32(0);

  q8s16 = vld1q_s16(input);
  q9s16 = vld1q_s16(input + 8);

  d16s16 = vget_low_s16(q8s16);
  d17s16 = vget_high_s16(q8s16);
  d18s16 = vget_low_s16(q9s16);
  d19s16 = vget_high_s16(q9s16);

  d0x2s16 = vtrn_s16(d16s16, d17s16);
  d1x2s16 = vtrn_s16(d18s16, d19s16);
  q8s16 = vcombine_s16(d0x2s16.val[0], d0x2s16.val[1]);
  q9s16 = vcombine_s16(d1x2s16.val[0], d1x2s16.val[1]);

  d20s16 = vdup_n_s16(cospi_8_64);
  d21s16 = vdup_n_s16(cospi_16_64);

  q0x2s32 =
      vtrnq_s32(vreinterpretq_s32_s16(q8s16), vreinterpretq_s32_s16(q9s16));
  d16s16 = vget_low_s16(vreinterpretq_s16_s32(q0x2s32.val[0]));
  d17s16 = vget_high_s16(vreinterpretq_s16_s32(q0x2s32.val[0]));
  d18s16 = vget_low_s16(vreinterpretq_s16_s32(q0x2s32.val[1]));
  d19s16 = vget_high_s16(vreinterpretq_s16_s32(q0x2s32.val[1]));

  d22s16 = vdup_n_s16(cospi_24_64);

  // stage 1
  d23s16 = vadd_s16(d16s16, d18s16);
  d24s16 = vsub_s16(d16s16, d18s16);

  q15s32 = vmull_s16(d17s16, d22s16);
  q1s32 = vmull_s16(d17s16, d20s16);
  q13s32 = vmull_s16(d23s16, d21s16);
  q14s32 = vmull_s16(d24s16, d21s16);

  q15s32 = vmlsl_s16(q15s32, d19s16, d20s16);
  q1s32 = vmlal_s16(q1s32, d19s16, d22s16);

  d26s16 = vqrshrn_n_s32(q13s32, 14);
  d27s16 = vqrshrn_n_s32(q14s32, 14);
  d29s16 = vqrshrn_n_s32(q15s32, 14);
  d28s16 = vqrshrn_n_s32(q1s32, 14);
  q13s16 = vcombine_s16(d26s16, d27s16);
  q14s16 = vcombine_s16(d28s16, d29s16);

  // stage 2
  q8s16 = vaddq_s16(q13s16, q14s16);
  q9s16 = vsubq_s16(q13s16, q14s16);

  d16s16 = vget_low_s16(q8s16);
  d17s16 = vget_high_s16(q8s16);
  d18s16 = vget_high_s16(q9s16);  // vswp d18 d19
  d19s16 = vget_low_s16(q9s16);

  d0x2s16 = vtrn_s16(d16s16, d17s16);
  d1x2s16 = vtrn_s16(d18s16, d19s16);
  q8s16 = vcombine_s16(d0x2s16.val[0], d0x2s16.val[1]);
  q9s16 = vcombine_s16(d1x2s16.val[0], d1x2s16.val[1]);

  q0x2s32 =
      vtrnq_s32(vreinterpretq_s32_s16(q8s16), vreinterpretq_s32_s16(q9s16));
  d16s16 = vget_low_s16(vreinterpretq_s16_s32(q0x2s32.val[0]));
  d17s16 = vget_high_s16(vreinterpretq_s16_s32(q0x2s32.val[0]));
  d18s16 = vget_low_s16(vreinterpretq_s16_s32(q0x2s32.val[1]));
  d19s16 = vget_high_s16(vreinterpretq_s16_s32(q0x2s32.val[1]));

  // do the transform on columns
  // stage 1
  d23s16 = vadd_s16(d16s16, d18s16);
  d24s16 = vsub_s16(d16s16, d18s16);

  q15s32 = vmull_s16(d17s16, d22s16);
  q1s32 = vmull_s16(d17s16, d20s16);
  q13s32 = vmull_s16(d23s16, d21s16);
  q14s32 = vmull_s16(d24s16, d21s16);

  q15s32 = vmlsl_s16(q15s32, d19s16, d20s16);
  q1s32 = vmlal_s16(q1s32, d19s16, d22s16);

  d26s16 = vqrshrn_n_s32(q13s32, 14);
  d27s16 = vqrshrn_n_s32(q14s32, 14);
  d29s16 = vqrshrn_n_s32(q15s32, 14);
  d28s16 = vqrshrn_n_s32(q1s32, 14);
  q13s16 = vcombine_s16(d26s16, d27s16);
  q14s16 = vcombine_s16(d28s16, d29s16);

  // stage 2
  q8s16 = vaddq_s16(q13s16, q14s16);
  q9s16 = vsubq_s16(q13s16, q14s16);

  q8s16 = vrshrq_n_s16(q8s16, 4);
  q9s16 = vrshrq_n_s16(q9s16, 4);

  d = dest;
  d26u32 = vld1_lane_u32((const uint32_t *)d, d26u32, 0);
  d += dest_stride;
  d26u32 = vld1_lane_u32((const uint32_t *)d, d26u32, 1);
  d += dest_stride;
  d27u32 = vld1_lane_u32((const uint32_t *)d, d27u32, 1);
  d += dest_stride;
  d27u32 = vld1_lane_u32((const uint32_t *)d, d27u32, 0);

  q8u16 = vaddw_u8(vreinterpretq_u16_s16(q8s16), vreinterpret_u8_u32(d26u32));
  q9u16 = vaddw_u8(vreinterpretq_u16_s16(q9s16), vreinterpret_u8_u32(d27u32));

  d26u8 = vqmovun_s16(vreinterpretq_s16_u16(q8u16));
  d27u8 = vqmovun_s16(vreinterpretq_s16_u16(q9u16));

  d = dest;
  vst1_lane_u32((uint32_t *)d, vreinterpret_u32_u8(d26u8), 0);
  d += dest_stride;
  vst1_lane_u32((uint32_t *)d, vreinterpret_u32_u8(d26u8), 1);
  d += dest_stride;
  vst1_lane_u32((uint32_t *)d, vreinterpret_u32_u8(d27u8), 1);
  d += dest_stride;
  vst1_lane_u32((uint32_t *)d, vreinterpret_u32_u8(d27u8), 0);
  return;
}