287 lines
7.9 KiB
C
287 lines
7.9 KiB
C
/* ----------------------------------------------------------------------
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* Project: CMSIS DSP Library
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* Title: arm_biquad_cascade_stereo_df2T_f32.c
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* Description: Processing function for floating-point transposed direct form II Biquad cascade filter. 2 channels
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*
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* $Date: 18. March 2019
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* $Revision: V1.6.0
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*
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* Target Processor: Cortex-M cores
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* -------------------------------------------------------------------- */
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/*
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* Copyright (C) 2010-2019 ARM Limited or its affiliates. All rights reserved.
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*
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* SPDX-License-Identifier: Apache-2.0
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*
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* Licensed under the Apache License, Version 2.0 (the License); you may
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* not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an AS IS BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "arm_math.h"
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/**
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@ingroup groupFilters
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*/
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/**
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@addtogroup BiquadCascadeDF2T
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@{
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*/
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/**
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@brief Processing function for the floating-point transposed direct form II Biquad cascade filter.
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@param[in] S points to an instance of the filter data structure
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@param[in] pSrc points to the block of input data
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@param[out] pDst points to the block of output data
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@param[in] blockSize number of samples to process
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@return none
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*/
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LOW_OPTIMIZATION_ENTER
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void arm_biquad_cascade_stereo_df2T_f32(
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const arm_biquad_cascade_stereo_df2T_instance_f32 * S,
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const float32_t * pSrc,
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float32_t * pDst,
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uint32_t blockSize)
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{
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const float32_t *pIn = pSrc; /* Source pointer */
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float32_t *pOut = pDst; /* Destination pointer */
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float32_t *pState = S->pState; /* State pointer */
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const float32_t *pCoeffs = S->pCoeffs; /* Coefficient pointer */
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float32_t acc1a, acc1b; /* Accumulator */
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float32_t b0, b1, b2, a1, a2; /* Filter coefficients */
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float32_t Xn1a, Xn1b; /* Temporary input */
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float32_t d1a, d2a, d1b, d2b; /* State variables */
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uint32_t sample, stage = S->numStages; /* Loop counters */
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do
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{
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/* Reading the coefficients */
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b0 = pCoeffs[0];
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b1 = pCoeffs[1];
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b2 = pCoeffs[2];
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a1 = pCoeffs[3];
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a2 = pCoeffs[4];
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/* Reading the state values */
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d1a = pState[0];
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d2a = pState[1];
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d1b = pState[2];
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d2b = pState[3];
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pCoeffs += 5U;
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#if defined (ARM_MATH_LOOPUNROLL)
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/* Loop unrolling: Compute 8 outputs at a time */
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sample = blockSize >> 3U;
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while (sample > 0U) {
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/* y[n] = b0 * x[n] + d1 */
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/* d1 = b1 * x[n] + a1 * y[n] + d2 */
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/* d2 = b2 * x[n] + a2 * y[n] */
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/* 1 */
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Xn1a = *pIn++; /* Channel a */
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Xn1b = *pIn++; /* Channel b */
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acc1a = (b0 * Xn1a) + d1a;
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acc1b = (b0 * Xn1b) + d1b;
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*pOut++ = acc1a;
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*pOut++ = acc1b;
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d1a = ((b1 * Xn1a) + (a1 * acc1a)) + d2a;
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d1b = ((b1 * Xn1b) + (a1 * acc1b)) + d2b;
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d2a = (b2 * Xn1a) + (a2 * acc1a);
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d2b = (b2 * Xn1b) + (a2 * acc1b);
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/* 2 */
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Xn1a = *pIn++; /* Channel a */
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Xn1b = *pIn++; /* Channel b */
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acc1a = (b0 * Xn1a) + d1a;
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acc1b = (b0 * Xn1b) + d1b;
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*pOut++ = acc1a;
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*pOut++ = acc1b;
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d1a = ((b1 * Xn1a) + (a1 * acc1a)) + d2a;
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d1b = ((b1 * Xn1b) + (a1 * acc1b)) + d2b;
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d2a = (b2 * Xn1a) + (a2 * acc1a);
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d2b = (b2 * Xn1b) + (a2 * acc1b);
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/* 3 */
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Xn1a = *pIn++; /* Channel a */
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Xn1b = *pIn++; /* Channel b */
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acc1a = (b0 * Xn1a) + d1a;
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acc1b = (b0 * Xn1b) + d1b;
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*pOut++ = acc1a;
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*pOut++ = acc1b;
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d1a = ((b1 * Xn1a) + (a1 * acc1a)) + d2a;
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d1b = ((b1 * Xn1b) + (a1 * acc1b)) + d2b;
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d2a = (b2 * Xn1a) + (a2 * acc1a);
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d2b = (b2 * Xn1b) + (a2 * acc1b);
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/* 4 */
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Xn1a = *pIn++; /* Channel a */
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Xn1b = *pIn++; /* Channel b */
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acc1a = (b0 * Xn1a) + d1a;
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acc1b = (b0 * Xn1b) + d1b;
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*pOut++ = acc1a;
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*pOut++ = acc1b;
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d1a = ((b1 * Xn1a) + (a1 * acc1a)) + d2a;
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d1b = ((b1 * Xn1b) + (a1 * acc1b)) + d2b;
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d2a = (b2 * Xn1a) + (a2 * acc1a);
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d2b = (b2 * Xn1b) + (a2 * acc1b);
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/* 5 */
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Xn1a = *pIn++; /* Channel a */
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Xn1b = *pIn++; /* Channel b */
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acc1a = (b0 * Xn1a) + d1a;
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acc1b = (b0 * Xn1b) + d1b;
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*pOut++ = acc1a;
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*pOut++ = acc1b;
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d1a = ((b1 * Xn1a) + (a1 * acc1a)) + d2a;
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d1b = ((b1 * Xn1b) + (a1 * acc1b)) + d2b;
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d2a = (b2 * Xn1a) + (a2 * acc1a);
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d2b = (b2 * Xn1b) + (a2 * acc1b);
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/* 6 */
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Xn1a = *pIn++; /* Channel a */
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Xn1b = *pIn++; /* Channel b */
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acc1a = (b0 * Xn1a) + d1a;
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acc1b = (b0 * Xn1b) + d1b;
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*pOut++ = acc1a;
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*pOut++ = acc1b;
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d1a = ((b1 * Xn1a) + (a1 * acc1a)) + d2a;
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d1b = ((b1 * Xn1b) + (a1 * acc1b)) + d2b;
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d2a = (b2 * Xn1a) + (a2 * acc1a);
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d2b = (b2 * Xn1b) + (a2 * acc1b);
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/* 7 */
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Xn1a = *pIn++; /* Channel a */
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Xn1b = *pIn++; /* Channel b */
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acc1a = (b0 * Xn1a) + d1a;
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acc1b = (b0 * Xn1b) + d1b;
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*pOut++ = acc1a;
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*pOut++ = acc1b;
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d1a = ((b1 * Xn1a) + (a1 * acc1a)) + d2a;
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d1b = ((b1 * Xn1b) + (a1 * acc1b)) + d2b;
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d2a = (b2 * Xn1a) + (a2 * acc1a);
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d2b = (b2 * Xn1b) + (a2 * acc1b);
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/* 8 */
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Xn1a = *pIn++; /* Channel a */
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Xn1b = *pIn++; /* Channel b */
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acc1a = (b0 * Xn1a) + d1a;
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acc1b = (b0 * Xn1b) + d1b;
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*pOut++ = acc1a;
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*pOut++ = acc1b;
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d1a = ((b1 * Xn1a) + (a1 * acc1a)) + d2a;
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d1b = ((b1 * Xn1b) + (a1 * acc1b)) + d2b;
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d2a = (b2 * Xn1a) + (a2 * acc1a);
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d2b = (b2 * Xn1b) + (a2 * acc1b);
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/* decrement loop counter */
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sample--;
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}
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/* Loop unrolling: Compute remaining outputs */
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sample = blockSize & 0x7U;
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#else
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/* Initialize blkCnt with number of samples */
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sample = blockSize;
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#endif /* #if defined (ARM_MATH_LOOPUNROLL) */
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while (sample > 0U) {
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/* Read the input */
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Xn1a = *pIn++; /* Channel a */
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Xn1b = *pIn++; /* Channel b */
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/* y[n] = b0 * x[n] + d1 */
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acc1a = (b0 * Xn1a) + d1a;
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acc1b = (b0 * Xn1b) + d1b;
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/* Store the result in the accumulator in the destination buffer. */
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*pOut++ = acc1a;
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*pOut++ = acc1b;
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/* Every time after the output is computed state should be updated. */
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/* d1 = b1 * x[n] + a1 * y[n] + d2 */
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d1a = ((b1 * Xn1a) + (a1 * acc1a)) + d2a;
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d1b = ((b1 * Xn1b) + (a1 * acc1b)) + d2b;
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/* d2 = b2 * x[n] + a2 * y[n] */
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d2a = (b2 * Xn1a) + (a2 * acc1a);
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d2b = (b2 * Xn1b) + (a2 * acc1b);
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/* decrement loop counter */
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sample--;
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}
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/* Store the updated state variables back into the state array */
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pState[0] = d1a;
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pState[1] = d2a;
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pState[2] = d1b;
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pState[3] = d2b;
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pState += 4U;
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/* The current stage input is given as the output to the next stage */
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pIn = pDst;
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/* Reset the output working pointer */
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pOut = pDst;
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/* decrement the loop counter */
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stage--;
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} while (stage > 0U);
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}
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LOW_OPTIMIZATION_EXIT
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/**
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@} end of BiquadCascadeDF2T group
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*/
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