/*
 *  Copyright (c) 2023 The WebM project authors. All Rights Reserved.
 *  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_dsp_rtcd.h"
#include "aom/aom_integer.h"
#include "aom_dsp/arm/mem_neon.h"
#include "aom_dsp/arm/sum_neon.h"
#include "aom_ports/mem.h"

uint32_t aom_highbd_avg_4x4_neon(const uint8_t *a, int a_stride) {
  const uint16_t *a_ptr = CONVERT_TO_SHORTPTR(a);
  uint16x4_t sum, a0, a1, a2, a3;

  load_u16_4x4(a_ptr, a_stride, &a0, &a1, &a2, &a3);

  sum = vadd_u16(a0, a1);
  sum = vadd_u16(sum, a2);
  sum = vadd_u16(sum, a3);

  return (horizontal_add_u16x4(sum) + (1 << 3)) >> 4;
}

uint32_t aom_highbd_avg_8x8_neon(const uint8_t *a, int a_stride) {
  const uint16_t *a_ptr = CONVERT_TO_SHORTPTR(a);
  uint16x8_t sum, a0, a1, a2, a3, a4, a5, a6, a7;

  load_u16_8x8(a_ptr, a_stride, &a0, &a1, &a2, &a3, &a4, &a5, &a6, &a7);

  sum = vaddq_u16(a0, a1);
  sum = vaddq_u16(sum, a2);
  sum = vaddq_u16(sum, a3);
  sum = vaddq_u16(sum, a4);
  sum = vaddq_u16(sum, a5);
  sum = vaddq_u16(sum, a6);
  sum = vaddq_u16(sum, a7);

  return (horizontal_add_u16x8(sum) + (1 << 5)) >> 6;
}

void aom_highbd_minmax_8x8_neon(const uint8_t *s8, int p, const uint8_t *d8,
                                int dp, int *min, int *max) {
  const uint16_t *a_ptr = CONVERT_TO_SHORTPTR(s8);
  const uint16_t *b_ptr = CONVERT_TO_SHORTPTR(d8);

  const uint16x8_t a0 = vld1q_u16(a_ptr + 0 * p);
  const uint16x8_t a1 = vld1q_u16(a_ptr + 1 * p);
  const uint16x8_t a2 = vld1q_u16(a_ptr + 2 * p);
  const uint16x8_t a3 = vld1q_u16(a_ptr + 3 * p);
  const uint16x8_t a4 = vld1q_u16(a_ptr + 4 * p);
  const uint16x8_t a5 = vld1q_u16(a_ptr + 5 * p);
  const uint16x8_t a6 = vld1q_u16(a_ptr + 6 * p);
  const uint16x8_t a7 = vld1q_u16(a_ptr + 7 * p);

  const uint16x8_t b0 = vld1q_u16(b_ptr + 0 * dp);
  const uint16x8_t b1 = vld1q_u16(b_ptr + 1 * dp);
  const uint16x8_t b2 = vld1q_u16(b_ptr + 2 * dp);
  const uint16x8_t b3 = vld1q_u16(b_ptr + 3 * dp);
  const uint16x8_t b4 = vld1q_u16(b_ptr + 4 * dp);
  const uint16x8_t b5 = vld1q_u16(b_ptr + 5 * dp);
  const uint16x8_t b6 = vld1q_u16(b_ptr + 6 * dp);
  const uint16x8_t b7 = vld1q_u16(b_ptr + 7 * dp);

  const uint16x8_t abs_diff0 = vabdq_u16(a0, b0);
  const uint16x8_t abs_diff1 = vabdq_u16(a1, b1);
  const uint16x8_t abs_diff2 = vabdq_u16(a2, b2);
  const uint16x8_t abs_diff3 = vabdq_u16(a3, b3);
  const uint16x8_t abs_diff4 = vabdq_u16(a4, b4);
  const uint16x8_t abs_diff5 = vabdq_u16(a5, b5);
  const uint16x8_t abs_diff6 = vabdq_u16(a6, b6);
  const uint16x8_t abs_diff7 = vabdq_u16(a7, b7);

  const uint16x8_t max01 = vmaxq_u16(abs_diff0, abs_diff1);
  const uint16x8_t max23 = vmaxq_u16(abs_diff2, abs_diff3);
  const uint16x8_t max45 = vmaxq_u16(abs_diff4, abs_diff5);
  const uint16x8_t max67 = vmaxq_u16(abs_diff6, abs_diff7);

  const uint16x8_t max0123 = vmaxq_u16(max01, max23);
  const uint16x8_t max4567 = vmaxq_u16(max45, max67);
  const uint16x8_t max07 = vmaxq_u16(max0123, max4567);

  const uint16x8_t min01 = vminq_u16(abs_diff0, abs_diff1);
  const uint16x8_t min23 = vminq_u16(abs_diff2, abs_diff3);
  const uint16x8_t min45 = vminq_u16(abs_diff4, abs_diff5);
  const uint16x8_t min67 = vminq_u16(abs_diff6, abs_diff7);

  const uint16x8_t min0123 = vminq_u16(min01, min23);
  const uint16x8_t min4567 = vminq_u16(min45, min67);
  const uint16x8_t min07 = vminq_u16(min0123, min4567);

#if defined(__aarch64__)
  *max = (int)vmaxvq_u16(max07);
  *min = (int)vminvq_u16(min07);
#else
  // Split into 64-bit vectors and execute pairwise min/max.
  uint16x4_t ab_max = vmax_u16(vget_high_u16(max07), vget_low_u16(max07));
  uint16x4_t ab_min = vmin_u16(vget_high_u16(min07), vget_low_u16(min07));

  // Enough runs of vpmax/min propagate the max/min values to every position.
  ab_max = vpmax_u16(ab_max, ab_max);
  ab_min = vpmin_u16(ab_min, ab_min);

  ab_max = vpmax_u16(ab_max, ab_max);
  ab_min = vpmin_u16(ab_min, ab_min);

  ab_max = vpmax_u16(ab_max, ab_max);
  ab_min = vpmin_u16(ab_min, ab_min);

  *min = *max = 0;  // Clear high bits
  // Store directly to avoid costly neon->gpr transfer.
  vst1_lane_u16((uint16_t *)max, ab_max, 0);
  vst1_lane_u16((uint16_t *)min, ab_min, 0);
#endif
}