arm_fir_decimate_init_q31.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_decimate_init_q31.c    
*    
* Description:  Initialization function for Q31 FIR Decimation filter.    
*    
* 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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*
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#include "arm_math.h"

arm_status arm_fir_decimate_init_q31(
  arm_fir_decimate_instance_q31 * S,
  uint16_t numTaps,
  uint8_t M,
  q31_t * pCoeffs,
  q31_t * pState,
  uint32_t blockSize)
{
  arm_status status;

  /* The size of the input block must be a multiple of the decimation factor */
  if((blockSize % M) != 0u)
  {
    /* Set status as ARM_MATH_LENGTH_ERROR */
    status = ARM_MATH_LENGTH_ERROR;
  }
  else
  {
    /* Assign filter taps */
    S->numTaps = numTaps;

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

    /* Clear the state buffer.  The size is always (blockSize + numTaps - 1) */
    memset(pState, 0, (numTaps + (blockSize - 1)) * sizeof(q31_t));

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

    /* Assign Decimation factor */
    S->M = M;

    status = ARM_MATH_SUCCESS;
  }

  return (status);

}