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/* ----------------------------------------------------------------------
* Project: CMSIS DSP Library
* Title: arm_fir_init_q31.c
* Description: Q31 FIR filter initialization function.
*
* $Date: 27. January 2017
* $Revision: V.1.5.1
*
* Target Processor: Cortex-M cores
* -------------------------------------------------------------------- */
/*
* Copyright (C) 2010-2017 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 FIR
* @{
*/
/**
* @details
*
* @param[in,out] *S points to an instance of the Q31 FIR filter structure.
* @param[in] numTaps Number of filter coefficients in the filter.
* @param[in] *pCoeffs points to the filter coefficients buffer.
* @param[in] *pState points to the state buffer.
* @param[in] blockSize number of samples that are processed per call.
* @return none.
*
* <b>Description:</b>
* \par
* <code>pCoeffs</code> points to the array of filter coefficients stored in time reversed order:
* <pre>
* {b[numTaps-1], b[numTaps-2], b[N-2], ..., b[1], b[0]}
* </pre>
* \par
* <code>pState</code> points to the array of state variables.
* <code>pState</code> is of length <code>numTaps+blockSize-1</code> samples, where <code>blockSize</code> is the number of input samples processed by each call to <code>arm_fir_q31()</code>.
*/
void arm_fir_init_q31(
arm_fir_instance_q31 * S,
uint16_t numTaps,
q31_t * pCoeffs,
q31_t * pState,
uint32_t blockSize)
{
/* Assign filter taps */
S->numTaps = numTaps;
/* Assign coefficient pointer */
S->pCoeffs = pCoeffs;
/* Clear state buffer and state array size is (blockSize + numTaps - 1) */
memset(pState, 0, (blockSize + ((uint32_t) numTaps - 1U)) * sizeof(q31_t));
/* Assign state pointer */
S->pState = pState;
}
/**
* @} end of FIR group
*/
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