| /* |
| * 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_neon.h" |
| |
| #include <arm_neon.h> |
| #include <string.h> |
| |
| #include "rtc_base/checks.h" |
| #include "rtc_base/memory/aligned_malloc.h" |
| |
| namespace webrtc { |
| |
| FIRFilterNEON::~FIRFilterNEON() {} |
| |
| FIRFilterNEON::FIRFilterNEON(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.f, 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.f, |
| (max_input_length + state_length_) * sizeof(state_[0])); |
| } |
| |
| void FIRFilterNEON::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(); |
| |
| float32x4_t m_sum = vmovq_n_f32(0); |
| float32x4_t m_in; |
| |
| for (size_t j = 0; j < coefficients_length_; j += 4) { |
| m_in = vld1q_f32(in_ptr + j); |
| m_sum = vmlaq_f32(m_sum, m_in, vld1q_f32(coef_ptr + j)); |
| } |
| |
| float32x2_t m_half = vadd_f32(vget_high_f32(m_sum), vget_low_f32(m_sum)); |
| out[i] = vget_lane_f32(vpadd_f32(m_half, m_half), 0); |
| } |
| |
| // Update current state. |
| memmove(state_.get(), &state_[length], state_length_ * sizeof(state_[0])); |
| } |
| |
| } // namespace webrtc |