DSP_Lib/Source/FilteringFunctions/arm_fir_sparse_init_q31.c

/* ----------------------------------------------------------------------    
* Copyright (C) 2010-2014 ARM Limited. All rights reserved.    
*    
* $Date:        19. March 2015
* $Revision: 	V.1.4.5
*    
* Project: 	    CMSIS DSP Library    
* Title:        arm_fir_sparse_init_q31.c    
*    
* Description:	Q31 sparse FIR filter initialization function.   
*    
* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
*  
* Redistribution and use in source and binary forms, with or without 
* modification, are permitted provided that the following conditions
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*     notice, this list of conditions and the following disclaimer.
*   - Redistributions in binary form must reproduce the above copyright
*     notice, this list of conditions and the following disclaimer in
*     the documentation and/or other materials provided with the 
*     distribution.
*   - Neither the name of ARM LIMITED nor the names of its contributors
*     may be used to endorse or promote products derived from this
*     software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* ---------------------------------------------------------------------------*/

#include "arm_math.h"

/**    
 * @ingroup groupFilters    
 */

/**    
 * @addtogroup FIR_Sparse    
 * @{    
 */

/**   
 * @brief  Initialization function for the Q31 sparse FIR filter.   
 * @param[in,out] *S         points to an instance of the Q31 sparse FIR structure.   
 * @param[in]     numTaps    number of nonzero coefficients in the filter.   
 * @param[in]     *pCoeffs   points to the array of filter coefficients.   
 * @param[in]     *pState    points to the state buffer.   
 * @param[in]     *pTapDelay points to the array of offset times.   
 * @param[in]     maxDelay   maximum offset time supported.   
 * @param[in]     blockSize  number of samples that will be processed per block.   
 * @return none   
 *    
 * <b>Description:</b>    
 * \par    
 * <code>pCoeffs</code> holds the filter coefficients and has length <code>numTaps</code>.    
 * <code>pState</code> holds the filter's state variables and must be of length    
 * <code>maxDelay + blockSize</code>, where <code>maxDelay</code>    
 * is the maximum number of delay line values.    
 * <code>blockSize</code> is the number of words processed by <code>arm_fir_sparse_q31()</code> function.    
 */

void arm_fir_sparse_init_q31(
  arm_fir_sparse_instance_q31 * S,
  uint16_t numTaps,
  q31_t * pCoeffs,
  q31_t * pState,
  int32_t * pTapDelay,
  uint16_t maxDelay,
  uint32_t blockSize)
{
  /* Assign filter taps */
  S->numTaps = numTaps;

  /* Assign coefficient pointer */
  S->pCoeffs = pCoeffs;

  /* Assign TapDelay pointer */
  S->pTapDelay = pTapDelay;

  /* Assign MaxDelay */
  S->maxDelay = maxDelay;

  /* reset the stateIndex to 0 */
  S->stateIndex = 0u;

  /* Clear state buffer and size is always maxDelay + blockSize */
  memset(pState, 0, (maxDelay + blockSize) * sizeof(q31_t));

  /* Assign state pointer */
  S->pState = pState;

}

/**    
 * @} end of FIR_Sparse group    
 */