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av1_k_means_neon.c (4140B)


      1 /*
      2 * Copyright (c) 2023, Alliance for Open Media. All rights reserved.
      3 *
      4 * This source code is subject to the terms of the BSD 2 Clause License and
      5 * the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
      6 * was not distributed with this source code in the LICENSE file, you can
      7 * obtain it at www.aomedia.org/license/software. If the Alliance for Open
      8 * Media Patent License 1.0 was not distributed with this source code in the
      9 * PATENTS file, you can obtain it at www.aomedia.org/license/patent.
     10 */
     11 
     12 #include <arm_neon.h>
     13 
     14 #include "aom_dsp/arm/sum_neon.h"
     15 #include "config/aom_config.h"
     16 #include "config/av1_rtcd.h"
     17 
     18 static int32x4_t k_means_multiply_add_neon(const int16x8_t a) {
     19  const int32x4_t l = vmull_s16(vget_low_s16(a), vget_low_s16(a));
     20  const int32x4_t h = vmull_s16(vget_high_s16(a), vget_high_s16(a));
     21 #if AOM_ARCH_AARCH64
     22  return vpaddq_s32(l, h);
     23 #else
     24  const int32x2_t dl = vpadd_s32(vget_low_s32(l), vget_high_s32(l));
     25  const int32x2_t dh = vpadd_s32(vget_low_s32(h), vget_high_s32(h));
     26  return vcombine_s32(dl, dh);
     27 #endif
     28 }
     29 
     30 void av1_calc_indices_dim1_neon(const int16_t *data, const int16_t *centroids,
     31                                uint8_t *indices, int64_t *total_dist, int n,
     32                                int k) {
     33  int64x2_t sum = vdupq_n_s64(0);
     34  int16x8_t cents[PALETTE_MAX_SIZE];
     35  for (int j = 0; j < k; ++j) {
     36    cents[j] = vdupq_n_s16(centroids[j]);
     37  }
     38 
     39  for (int i = 0; i < n; i += 8) {
     40    const int16x8_t in = vld1q_s16(data);
     41    uint16x8_t ind = vdupq_n_u16(0);
     42    // Compute the distance to the first centroid.
     43    int16x8_t dist_min = vabdq_s16(in, cents[0]);
     44 
     45    for (int j = 1; j < k; ++j) {
     46      // Compute the distance to the centroid.
     47      const int16x8_t dist = vabdq_s16(in, cents[j]);
     48      // Compare to the minimal one.
     49      const uint16x8_t cmp = vcgtq_s16(dist_min, dist);
     50      dist_min = vminq_s16(dist_min, dist);
     51      const uint16x8_t ind1 = vdupq_n_u16(j);
     52      ind = vbslq_u16(cmp, ind1, ind);
     53    }
     54    if (total_dist) {
     55      // Square, convert to 32 bit and add together.
     56      const int32x4_t l =
     57          vmull_s16(vget_low_s16(dist_min), vget_low_s16(dist_min));
     58      const int32x4_t sum32_tmp =
     59          vmlal_s16(l, vget_high_s16(dist_min), vget_high_s16(dist_min));
     60      // Pairwise sum, convert to 64 bit and add to sum.
     61      sum = vpadalq_s32(sum, sum32_tmp);
     62    }
     63    vst1_u8(indices, vmovn_u16(ind));
     64    indices += 8;
     65    data += 8;
     66  }
     67  if (total_dist) {
     68    *total_dist = horizontal_add_s64x2(sum);
     69  }
     70 }
     71 
     72 void av1_calc_indices_dim2_neon(const int16_t *data, const int16_t *centroids,
     73                                uint8_t *indices, int64_t *total_dist, int n,
     74                                int k) {
     75  int64x2_t sum = vdupq_n_s64(0);
     76  uint32x4_t ind[2];
     77  int16x8_t cents[PALETTE_MAX_SIZE];
     78  for (int j = 0; j < k; ++j) {
     79    const int16_t cx = centroids[2 * j], cy = centroids[2 * j + 1];
     80    const int16_t cxcy[8] = { cx, cy, cx, cy, cx, cy, cx, cy };
     81    cents[j] = vld1q_s16(cxcy);
     82  }
     83 
     84  for (int i = 0; i < n; i += 8) {
     85    for (int l = 0; l < 2; ++l) {
     86      const int16x8_t in = vld1q_s16(data);
     87      ind[l] = vdupq_n_u32(0);
     88      // Compute the distance to the first centroid.
     89      int16x8_t d1 = vsubq_s16(in, cents[0]);
     90      int32x4_t dist_min = k_means_multiply_add_neon(d1);
     91 
     92      for (int j = 1; j < k; ++j) {
     93        // Compute the distance to the centroid.
     94        d1 = vsubq_s16(in, cents[j]);
     95        const int32x4_t dist = k_means_multiply_add_neon(d1);
     96        // Compare to the minimal one.
     97        const uint32x4_t cmp = vcgtq_s32(dist_min, dist);
     98        dist_min = vminq_s32(dist_min, dist);
     99        const uint32x4_t ind1 = vdupq_n_u32(j);
    100        ind[l] = vbslq_u32(cmp, ind1, ind[l]);
    101      }
    102      if (total_dist) {
    103        // Pairwise sum, convert to 64 bit and add to sum.
    104        sum = vpadalq_s32(sum, dist_min);
    105      }
    106      data += 8;
    107    }
    108    // Cast to 8 bit and store.
    109    vst1_u8(indices,
    110            vmovn_u16(vcombine_u16(vmovn_u32(ind[0]), vmovn_u32(ind[1]))));
    111    indices += 8;
    112  }
    113  if (total_dist) {
    114    *total_dist = horizontal_add_s64x2(sum);
    115  }
    116 }