77 lines
2.6 KiB
C++
77 lines
2.6 KiB
C++
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/*
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* Copyright (c) 2014 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#if defined(__arm__) || defined(_M_ARM) || defined(__aarch64__)
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#include "common_audio/fir_filter_neon.h"
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#include <arm_neon.h>
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#include <string.h>
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#include "rtc_base/checks.h"
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#include "rtc_base/memory/aligned_malloc.h"
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namespace webrtc {
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FIRFilterNEON::~FIRFilterNEON() {}
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FIRFilterNEON::FIRFilterNEON(const float* coefficients,
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size_t coefficients_length,
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size_t max_input_length)
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: // Closest higher multiple of four.
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coefficients_length_((coefficients_length + 3) & ~0x03),
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state_length_(coefficients_length_ - 1),
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coefficients_(static_cast<float*>(
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AlignedMalloc(sizeof(float) * coefficients_length_, 16))),
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state_(static_cast<float*>(
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AlignedMalloc(sizeof(float) * (max_input_length + state_length_),
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16))) {
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// Add zeros at the end of the coefficients.
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size_t padding = coefficients_length_ - coefficients_length;
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memset(coefficients_.get(), 0.f, padding * sizeof(coefficients_[0]));
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// The coefficients are reversed to compensate for the order in which the
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// input samples are acquired (most recent last).
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for (size_t i = 0; i < coefficients_length; ++i) {
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coefficients_[i + padding] = coefficients[coefficients_length - i - 1];
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}
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memset(state_.get(), 0.f,
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(max_input_length + state_length_) * sizeof(state_[0]));
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}
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void FIRFilterNEON::Filter(const float* in, size_t length, float* out) {
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RTC_DCHECK_GT(length, 0);
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memcpy(&state_[state_length_], in, length * sizeof(*in));
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// Convolves the input signal |in| with the filter kernel |coefficients_|
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// taking into account the previous state.
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for (size_t i = 0; i < length; ++i) {
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float* in_ptr = &state_[i];
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float* coef_ptr = coefficients_.get();
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float32x4_t m_sum = vmovq_n_f32(0);
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float32x4_t m_in;
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for (size_t j = 0; j < coefficients_length_; j += 4) {
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m_in = vld1q_f32(in_ptr + j);
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m_sum = vmlaq_f32(m_sum, m_in, vld1q_f32(coef_ptr + j));
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}
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float32x2_t m_half = vadd_f32(vget_high_f32(m_sum), vget_low_f32(m_sum));
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out[i] = vget_lane_f32(vpadd_f32(m_half, m_half), 0);
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}
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// Update current state.
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memmove(state_.get(), &state_[length], state_length_ * sizeof(state_[0]));
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}
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} // namespace webrtc
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#endif
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