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