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/* ----------------------------------------------------------------------
* Project: CMSIS DSP Library
* Title: arm_iir_lattice_init_q15.c
* Description: Q15 IIR lattice filter initialization function
*
* $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 IIR_Lattice
@{
*/
/**
@brief Initialization function for the Q15 IIR lattice filter.
@param[in] S points to an instance of the Q15 IIR lattice structure
@param[in] numStages number of stages in the filter
@param[in] pkCoeffs points to reflection coefficient buffer. The array is of length numStages
@param[in] pvCoeffs points to ladder coefficient buffer. The array is of length numStages+1
@param[in] pState points to state buffer. The array is of length numStages+blockSize
@param[in] blockSize number of samples to process
@return none
*/
void arm_iir_lattice_init_q15(
arm_iir_lattice_instance_q15 * S,
uint16_t numStages,
q15_t * pkCoeffs,
q15_t * pvCoeffs,
q15_t * pState,
uint32_t blockSize)
{
/* Assign filter taps */
S->numStages = numStages;
/* Assign reflection coefficient pointer */
S->pkCoeffs = pkCoeffs;
/* Assign ladder coefficient pointer */
S->pvCoeffs = pvCoeffs;
/* Clear state buffer and size is always blockSize + numStages */
memset(pState, 0, (numStages + blockSize) * sizeof(q15_t));
/* Assign state pointer */
S->pState = pState;
}
/**
@} end of IIR_Lattice group
*/
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