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/*
* Copyright (c) 2020 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#include "modules/audio_processing/aec3/matched_filter.h"
#include <immintrin.h>
#include "rtc_base/checks.h"
namespace webrtc {
namespace aec3 {
void MatchedFilterCore_AVX2(size_t x_start_index,
float x2_sum_threshold,
float smoothing,
rtc::ArrayView<const float> x,
rtc::ArrayView<const float> y,
rtc::ArrayView<float> h,
bool* filters_updated,
float* error_sum) {
const int h_size = static_cast<int>(h.size());
const int x_size = static_cast<int>(x.size());
RTC_DCHECK_EQ(0, h_size % 8);
// Process for all samples in the sub-block.
for (size_t i = 0; i < y.size(); ++i) {
// Apply the matched filter as filter * x, and compute x * x.
RTC_DCHECK_GT(x_size, x_start_index);
const float* x_p = &x[x_start_index];
const float* h_p = &h[0];
// Initialize values for the accumulation.
__m256 s_256 = _mm256_set1_ps(0);
__m256 x2_sum_256 = _mm256_set1_ps(0);
float x2_sum = 0.f;
float s = 0;
// Compute loop chunk sizes until, and after, the wraparound of the circular
// buffer for x.
const int chunk1 =
std::min(h_size, static_cast<int>(x_size - x_start_index));
// Perform the loop in two chunks.
const int chunk2 = h_size - chunk1;
for (int limit : {chunk1, chunk2}) {
// Perform 256 bit vector operations.
const int limit_by_8 = limit >> 3;
for (int k = limit_by_8; k > 0; --k, h_p += 8, x_p += 8) {
// Load the data into 256 bit vectors.
__m256 x_k = _mm256_loadu_ps(x_p);
__m256 h_k = _mm256_loadu_ps(h_p);
// Compute and accumulate x * x and h * x.
x2_sum_256 = _mm256_fmadd_ps(x_k, x_k, x2_sum_256);
s_256 = _mm256_fmadd_ps(h_k, x_k, s_256);
}
// Perform non-vector operations for any remaining items.
for (int k = limit - limit_by_8 * 8; k > 0; --k, ++h_p, ++x_p) {
const float x_k = *x_p;
x2_sum += x_k * x_k;
s += *h_p * x_k;
}
x_p = &x[0];
}
// Sum components together.
__m128 x2_sum_128 = _mm_add_ps(_mm256_extractf128_ps(x2_sum_256, 0),
_mm256_extractf128_ps(x2_sum_256, 1));
__m128 s_128 = _mm_add_ps(_mm256_extractf128_ps(s_256, 0),
_mm256_extractf128_ps(s_256, 1));
// Combine the accumulated vector and scalar values.
float* v = reinterpret_cast<float*>(&x2_sum_128);
x2_sum += v[0] + v[1] + v[2] + v[3];
v = reinterpret_cast<float*>(&s_128);
s += v[0] + v[1] + v[2] + v[3];
// Compute the matched filter error.
float e = y[i] - s;
const bool saturation = y[i] >= 32000.f || y[i] <= -32000.f;
(*error_sum) += e * e;
// Update the matched filter estimate in an NLMS manner.
if (x2_sum > x2_sum_threshold && !saturation) {
RTC_DCHECK_LT(0.f, x2_sum);
const float alpha = smoothing * e / x2_sum;
const __m256 alpha_256 = _mm256_set1_ps(alpha);
// filter = filter + smoothing * (y - filter * x) * x / x * x.
float* h_p = &h[0];
x_p = &x[x_start_index];
// Perform the loop in two chunks.
for (int limit : {chunk1, chunk2}) {
// Perform 256 bit vector operations.
const int limit_by_8 = limit >> 3;
for (int k = limit_by_8; k > 0; --k, h_p += 8, x_p += 8) {
// Load the data into 256 bit vectors.
__m256 h_k = _mm256_loadu_ps(h_p);
__m256 x_k = _mm256_loadu_ps(x_p);
// Compute h = h + alpha * x.
h_k = _mm256_fmadd_ps(x_k, alpha_256, h_k);
// Store the result.
_mm256_storeu_ps(h_p, h_k);
}
// Perform non-vector operations for any remaining items.
for (int k = limit - limit_by_8 * 8; k > 0; --k, ++h_p, ++x_p) {
*h_p += alpha * *x_p;
}
x_p = &x[0];
}
*filters_updated = true;
}
x_start_index = x_start_index > 0 ? x_start_index - 1 : x_size - 1;
}
}
} // namespace aec3
} // namespace webrtc
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