/*
 * Copyright (c) 2023, 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>
#include "config/aom_config.h"
#include "config/aom_dsp_rtcd.h"
#include "mem_neon.h"
#include "sum_neon.h"

static inline void obmc_sad_8x1_s16_neon(int16x8_t ref_s16, const int32_t *mask,
                                         const int32_t *wsrc, uint32x4_t *sum) {
  int32x4_t wsrc_lo = vld1q_s32(wsrc);
  int32x4_t wsrc_hi = vld1q_s32(wsrc + 4);

  int32x4_t mask_lo = vld1q_s32(mask);
  int32x4_t mask_hi = vld1q_s32(mask + 4);

  int16x8_t mask_s16 =
      vuzpq_s16(vreinterpretq_s16_s32(mask_lo), vreinterpretq_s16_s32(mask_hi))
          .val[0];

  int32x4_t pre_lo = vmull_s16(vget_low_s16(ref_s16), vget_low_s16(mask_s16));
  int32x4_t pre_hi = vmull_s16(vget_high_s16(ref_s16), vget_high_s16(mask_s16));

  uint32x4_t abs_lo = vreinterpretq_u32_s32(vabdq_s32(wsrc_lo, pre_lo));
  uint32x4_t abs_hi = vreinterpretq_u32_s32(vabdq_s32(wsrc_hi, pre_hi));

  *sum = vrsraq_n_u32(*sum, abs_lo, 12);
  *sum = vrsraq_n_u32(*sum, abs_hi, 12);
}

#if AOM_ARCH_AARCH64

// Use tbl for doing a double-width zero extension from 8->32 bits since we can
// do this in one instruction rather than two (indices out of range (255 here)
// are set to zero by tbl).
DECLARE_ALIGNED(16, static const uint8_t, obmc_variance_permute_idx[]) = {
  0,  255, 255, 255, 1,  255, 255, 255, 2,  255, 255, 255, 3,  255, 255, 255,
  4,  255, 255, 255, 5,  255, 255, 255, 6,  255, 255, 255, 7,  255, 255, 255,
  8,  255, 255, 255, 9,  255, 255, 255, 10, 255, 255, 255, 11, 255, 255, 255,
  12, 255, 255, 255, 13, 255, 255, 255, 14, 255, 255, 255, 15, 255, 255, 255
};

static inline void obmc_sad_8x1_s32_neon(uint32x4_t ref_u32_lo,
                                         uint32x4_t ref_u32_hi,
                                         const int32_t *mask,
                                         const int32_t *wsrc,
                                         uint32x4_t sum[2]) {
  int32x4_t wsrc_lo = vld1q_s32(wsrc);
  int32x4_t wsrc_hi = vld1q_s32(wsrc + 4);
  int32x4_t mask_lo = vld1q_s32(mask);
  int32x4_t mask_hi = vld1q_s32(mask + 4);

  int32x4_t pre_lo = vmulq_s32(vreinterpretq_s32_u32(ref_u32_lo), mask_lo);
  int32x4_t pre_hi = vmulq_s32(vreinterpretq_s32_u32(ref_u32_hi), mask_hi);

  uint32x4_t abs_lo = vreinterpretq_u32_s32(vabdq_s32(wsrc_lo, pre_lo));
  uint32x4_t abs_hi = vreinterpretq_u32_s32(vabdq_s32(wsrc_hi, pre_hi));

  sum[0] = vrsraq_n_u32(sum[0], abs_lo, 12);
  sum[1] = vrsraq_n_u32(sum[1], abs_hi, 12);
}

static inline unsigned int obmc_sad_large_neon(const uint8_t *ref,
                                               int ref_stride,
                                               const int32_t *wsrc,
                                               const int32_t *mask, int width,
                                               int height) {
  uint32x4_t sum[2] = { vdupq_n_u32(0), vdupq_n_u32(0) };

  // Use tbl for doing a double-width zero extension from 8->32 bits since we
  // can do this in one instruction rather than two.
  uint8x16_t pre_idx0 = vld1q_u8(&obmc_variance_permute_idx[0]);
  uint8x16_t pre_idx1 = vld1q_u8(&obmc_variance_permute_idx[16]);
  uint8x16_t pre_idx2 = vld1q_u8(&obmc_variance_permute_idx[32]);
  uint8x16_t pre_idx3 = vld1q_u8(&obmc_variance_permute_idx[48]);

  int h = height;
  do {
    int w = width;
    const uint8_t *ref_ptr = ref;
    do {
      uint8x16_t r = vld1q_u8(ref_ptr);

      uint32x4_t ref_u32_lo = vreinterpretq_u32_u8(vqtbl1q_u8(r, pre_idx0));
      uint32x4_t ref_u32_hi = vreinterpretq_u32_u8(vqtbl1q_u8(r, pre_idx1));
      obmc_sad_8x1_s32_neon(ref_u32_lo, ref_u32_hi, mask, wsrc, sum);

      ref_u32_lo = vreinterpretq_u32_u8(vqtbl1q_u8(r, pre_idx2));
      ref_u32_hi = vreinterpretq_u32_u8(vqtbl1q_u8(r, pre_idx3));
      obmc_sad_8x1_s32_neon(ref_u32_lo, ref_u32_hi, mask + 8, wsrc + 8, sum);

      ref_ptr += 16;
      wsrc += 16;
      mask += 16;
      w -= 16;
    } while (w != 0);

    ref += ref_stride;
  } while (--h != 0);

  return horizontal_add_u32x4(vaddq_u32(sum[0], sum[1]));
}

#else  // !AOM_ARCH_AARCH64

static inline unsigned int obmc_sad_large_neon(const uint8_t *ref,
                                               int ref_stride,
                                               const int32_t *wsrc,
                                               const int32_t *mask, int width,
                                               int height) {
  uint32x4_t sum = vdupq_n_u32(0);

  int h = height;
  do {
    int w = width;
    const uint8_t *ref_ptr = ref;
    do {
      uint8x16_t r = vld1q_u8(ref_ptr);

      int16x8_t ref_s16 = vreinterpretq_s16_u16(vmovl_u8(vget_low_u8(r)));
      obmc_sad_8x1_s16_neon(ref_s16, mask, wsrc, &sum);

      ref_s16 = vreinterpretq_s16_u16(vmovl_u8(vget_high_u8(r)));
      obmc_sad_8x1_s16_neon(ref_s16, mask + 8, wsrc + 8, &sum);

      ref_ptr += 16;
      wsrc += 16;
      mask += 16;
      w -= 16;
    } while (w != 0);

    ref += ref_stride;
  } while (--h != 0);

  return horizontal_add_u32x4(sum);
}

#endif  // AOM_ARCH_AARCH64

static inline unsigned int obmc_sad_128xh_neon(const uint8_t *ref,
                                               int ref_stride,
                                               const int32_t *wsrc,
                                               const int32_t *mask, int h) {
  return obmc_sad_large_neon(ref, ref_stride, wsrc, mask, 128, h);
}

static inline unsigned int obmc_sad_64xh_neon(const uint8_t *ref,
                                              int ref_stride,
                                              const int32_t *wsrc,
                                              const int32_t *mask, int h) {
  return obmc_sad_large_neon(ref, ref_stride, wsrc, mask, 64, h);
}

static inline unsigned int obmc_sad_32xh_neon(const uint8_t *ref,
                                              int ref_stride,
                                              const int32_t *wsrc,
                                              const int32_t *mask, int h) {
  return obmc_sad_large_neon(ref, ref_stride, wsrc, mask, 32, h);
}

static inline unsigned int obmc_sad_16xh_neon(const uint8_t *ref,
                                              int ref_stride,
                                              const int32_t *wsrc,
                                              const int32_t *mask, int h) {
  return obmc_sad_large_neon(ref, ref_stride, wsrc, mask, 16, h);
}

static inline unsigned int obmc_sad_8xh_neon(const uint8_t *ref, int ref_stride,
                                             const int32_t *wsrc,
                                             const int32_t *mask, int height) {
  uint32x4_t sum = vdupq_n_u32(0);

  int h = height;
  do {
    uint8x8_t r = vld1_u8(ref);

    int16x8_t ref_s16 = vreinterpretq_s16_u16(vmovl_u8(r));
    obmc_sad_8x1_s16_neon(ref_s16, mask, wsrc, &sum);

    ref += ref_stride;
    wsrc += 8;
    mask += 8;
  } while (--h != 0);

  return horizontal_add_u32x4(sum);
}

static inline unsigned int obmc_sad_4xh_neon(const uint8_t *ref, int ref_stride,
                                             const int32_t *wsrc,
                                             const int32_t *mask, int height) {
  uint32x4_t sum = vdupq_n_u32(0);

  int h = height / 2;
  do {
    uint8x8_t r = load_unaligned_u8(ref, ref_stride);

    int16x8_t ref_s16 = vreinterpretq_s16_u16(vmovl_u8(r));
    obmc_sad_8x1_s16_neon(ref_s16, mask, wsrc, &sum);

    ref += 2 * ref_stride;
    wsrc += 8;
    mask += 8;
  } while (--h != 0);

  return horizontal_add_u32x4(sum);
}

#define OBMC_SAD_WXH_NEON(w, h)                                   \
  unsigned int aom_obmc_sad##w##x##h##_neon(                      \
      const uint8_t *ref, int ref_stride, const int32_t *wsrc,    \
      const int32_t *mask) {                                      \
    return obmc_sad_##w##xh_neon(ref, ref_stride, wsrc, mask, h); \
  }

OBMC_SAD_WXH_NEON(4, 4)
OBMC_SAD_WXH_NEON(4, 8)
OBMC_SAD_WXH_NEON(4, 16)

OBMC_SAD_WXH_NEON(8, 4)
OBMC_SAD_WXH_NEON(8, 8)
OBMC_SAD_WXH_NEON(8, 16)
OBMC_SAD_WXH_NEON(8, 32)

OBMC_SAD_WXH_NEON(16, 4)
OBMC_SAD_WXH_NEON(16, 8)
OBMC_SAD_WXH_NEON(16, 16)
OBMC_SAD_WXH_NEON(16, 32)
OBMC_SAD_WXH_NEON(16, 64)

OBMC_SAD_WXH_NEON(32, 8)
OBMC_SAD_WXH_NEON(32, 16)
OBMC_SAD_WXH_NEON(32, 32)
OBMC_SAD_WXH_NEON(32, 64)

OBMC_SAD_WXH_NEON(64, 16)
OBMC_SAD_WXH_NEON(64, 32)
OBMC_SAD_WXH_NEON(64, 64)
OBMC_SAD_WXH_NEON(64, 128)

OBMC_SAD_WXH_NEON(128, 64)
OBMC_SAD_WXH_NEON(128, 128)