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/* ----------------------------------------------------------------------
* Project: CMSIS DSP Library
* Title: arm_fir_init_q31.c
* Description: Q31 FIR 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 FIR
@{
*/
/**
@brief Initialization function for the Q31 FIR filter.
@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 processed
@return none
@par Details
<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>
<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,
const q31_t * pCoeffs,
q31_t * pState,
uint32_t blockSize)
{
/* Assign filter taps */
S->numTaps = numTaps;
/* Assign coefficient pointer */
S->pCoeffs = pCoeffs;
/* Clear state buffer. The size is always (blockSize + numTaps - 1) */
memset(pState, 0, (numTaps + (blockSize - 1U)) * sizeof(q31_t));
/* Assign state pointer */
S->pState = pState;
}
/**
@} end of FIR group
*/
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