DSP_Lib/Source/FilteringFunctions/arm_iir_lattice_init_q15.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_iir_lattice_init_q15.c    
*    
* Description:  Q15 IIR lattice 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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*   - Redistributions in binary form must reproduce the above copyright
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*   - 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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* ---------------------------------------------------------------------------*/

#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 per call.    
   * @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    
 */