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/*
* Copyright (c) 2014 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 "common_audio/fir_filter_sse.h"
#include <stdint.h>
#include <string.h>
#include <xmmintrin.h>
#include "rtc_base/checks.h"
#include "rtc_base/memory/aligned_malloc.h"
namespace webrtc {
FIRFilterSSE2::~FIRFilterSSE2() {}
FIRFilterSSE2::FIRFilterSSE2(const float* coefficients,
size_t coefficients_length,
size_t max_input_length)
: // Closest higher multiple of four.
coefficients_length_((coefficients_length + 3) & ~0x03),
state_length_(coefficients_length_ - 1),
coefficients_(static_cast<float*>(
AlignedMalloc(sizeof(float) * coefficients_length_, 16))),
state_(static_cast<float*>(
AlignedMalloc(sizeof(float) * (max_input_length + state_length_),
16))) {
// Add zeros at the end of the coefficients.
size_t padding = coefficients_length_ - coefficients_length;
memset(coefficients_.get(), 0, padding * sizeof(coefficients_[0]));
// The coefficients are reversed to compensate for the order in which the
// input samples are acquired (most recent last).
for (size_t i = 0; i < coefficients_length; ++i) {
coefficients_[i + padding] = coefficients[coefficients_length - i - 1];
}
memset(state_.get(), 0,
(max_input_length + state_length_) * sizeof(state_[0]));
}
void FIRFilterSSE2::Filter(const float* in, size_t length, float* out) {
RTC_DCHECK_GT(length, 0);
memcpy(&state_[state_length_], in, length * sizeof(*in));
// Convolves the input signal `in` with the filter kernel `coefficients_`
// taking into account the previous state.
for (size_t i = 0; i < length; ++i) {
float* in_ptr = &state_[i];
float* coef_ptr = coefficients_.get();
__m128 m_sum = _mm_setzero_ps();
__m128 m_in;
// Depending on if the pointer is aligned with 16 bytes or not it is loaded
// differently.
if (reinterpret_cast<uintptr_t>(in_ptr) & 0x0F) {
for (size_t j = 0; j < coefficients_length_; j += 4) {
m_in = _mm_loadu_ps(in_ptr + j);
m_sum = _mm_add_ps(m_sum, _mm_mul_ps(m_in, _mm_load_ps(coef_ptr + j)));
}
} else {
for (size_t j = 0; j < coefficients_length_; j += 4) {
m_in = _mm_load_ps(in_ptr + j);
m_sum = _mm_add_ps(m_sum, _mm_mul_ps(m_in, _mm_load_ps(coef_ptr + j)));
}
}
m_sum = _mm_add_ps(_mm_movehl_ps(m_sum, m_sum), m_sum);
_mm_store_ss(out + i, _mm_add_ss(m_sum, _mm_shuffle_ps(m_sum, m_sum, 1)));
}
// Update current state.
memmove(state_.get(), &state_[length], state_length_ * sizeof(state_[0]));
}
} // namespace webrtc
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