hardware/arduino/sam/system/CMSIS/CMSIS/DSP_Lib/Source/FilteringFunctions/arm_lms_norm_init_q15.c

/*-----------------------------------------------------------------------------   
* Copyright (C) 2010 ARM Limited. All rights reserved.   
*   
* $Date:        15. July 2011  
* $Revision: 	V1.0.10  
*   
* Project: 	    CMSIS DSP Library   
* Title:        arm_lms_norm_init_q15.c   
*   
* Description:  Q15 NLMS initialization function.   
*   
* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
*  
* Version 1.0.10 2011/7/15 
*    Big Endian support added and Merged M0 and M3/M4 Source code.  
*   
* Version 1.0.3 2010/11/29  
*    Re-organized the CMSIS folders and updated documentation.   
*    
* Version 1.0.2 2010/11/11   
*    Documentation updated.    
*   
* Version 1.0.1 2010/10/05    
*    Production release and review comments incorporated.   
*   
* Version 1.0.0 2010/09/20    
*    Production release and review comments incorporated   
*   
* Version 0.0.7  2010/06/10    
*    Misra-C changes done   
* ---------------------------------------------------------------------------*/

#include "arm_math.h"
#include "arm_common_tables.h"

/**   
 * @addtogroup LMS_NORM   
 * @{   
 */

  /**   
   * @brief Initialization function for Q15 normalized LMS filter.   
   * @param[in] *S points to an instance of the Q15 normalized LMS filter structure.   
   * @param[in] numTaps  number of filter coefficients.   
   * @param[in] *pCoeffs points to coefficient buffer.   
   * @param[in] *pState points to state buffer.   
   * @param[in] mu step size that controls filter coefficient updates.   
   * @param[in] blockSize number of samples to process.   
   * @param[in] postShift bit shift applied to coefficients.   
   * @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>   
 * The initial filter coefficients serve as a starting point for the adaptive filter.   
 * <code>pState</code> points to the array of state variables and size of array is   
 * <code>numTaps+blockSize-1</code> samples, where <code>blockSize</code> is the number of input samples processed   
 * by each call to <code>arm_lms_norm_q15()</code>.   
 */

void arm_lms_norm_init_q15(
  arm_lms_norm_instance_q15 * S,
  uint16_t numTaps,
  q15_t * pCoeffs,
  q15_t * pState,
  q15_t mu,
  uint32_t blockSize,
  uint8_t postShift)
{
  /* Assign filter taps */
  S->numTaps = numTaps;

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

  /* Clear state buffer and size is always blockSize + numTaps - 1 */
  memset(pState, 0, (numTaps + (blockSize - 1u)) * sizeof(q15_t));

  /* Assign post Shift value applied to coefficients */
  S->postShift = postShift;

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

  /* Assign Step size value */
  S->mu = mu;

  /* Initialize reciprocal pointer table */
  S->recipTable = armRecipTableQ15;

  /* Initialise Energy to zero */
  S->energy = 0;

  /* Initialise x0 to zero */
  S->x0 = 0;

}

/**   
 * @} end of LMS_NORM group   
 */