arm_fir_interpolate_init_q15.c

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/*-----------------------------------------------------------------------------    
* 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_interpolate_init_q15.c    
*    
* Description:  Q15 FIR interpolator 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
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*     distribution.
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*     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
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* ---------------------------------------------------------------------------*/

#include "arm_math.h"

arm_status arm_fir_interpolate_init_q15(
  arm_fir_interpolate_instance_q15 * S,
  uint8_t L,
  uint16_t numTaps,
  q15_t * pCoeffs,
  q15_t * pState,
  uint32_t blockSize)
{
  arm_status status;

  /* The filter length must be a multiple of the interpolation factor */
  if((numTaps % L) != 0u)
  {
    /* Set status as ARM_MATH_LENGTH_ERROR */
    status = ARM_MATH_LENGTH_ERROR;
  }
  else
  {

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

    /* Assign Interpolation factor */
    S->L = L;

    /* Assign polyPhaseLength */
    S->phaseLength = numTaps / L;

    /* Clear state buffer and size of buffer is always phaseLength + blockSize - 1 */
    memset(pState, 0,
           (blockSize + ((uint32_t) S->phaseLength - 1u)) * sizeof(q15_t));

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

    status = ARM_MATH_SUCCESS;
  }

  return (status);

}