arm_fir_decimate_init_q15.c

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/* ----------------------------------------------------------------------      
* Copyright (C) 2011 ARM Limited. All rights reserved. 
*      
* $Date:        15. December 2011   
* $Revision:    V2.0.0  
*      
* Project:      Cortex-R DSP Library 
* Title:        arm_fir_decimate_init_q15.c      
*      
* Description:  Initialization function for the Q15 FIR Decimator.      
*      
* Target Processor:          Cortex-R4/R5
*
* Version 1.0.0 2011/03/08
*     Alpha release.
*
* Version 1.0.1 2011/09/30
*     Beta release.
*
* Version 2.0.0 2011/12/15
*     Final release. 
* 
* ------------------------------------------------------------------- */     
#include "arm_math.h"     
     
arm_status arm_fir_decimate_init_q15(     
  arm_fir_decimate_instance_q15 * S,     
  uint16_t numTaps,     
  uint8_t M,     
  q15_t * pCoeffs,     
  q15_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 of buffer is always (blockSize + numTaps - 1) */     
    memset(pState, 0, (numTaps + (blockSize - 1u)) * sizeof(q15_t));     
     
    /* Assign state pointer */     
    S->pState = pState;     
     
    /* Assign Decimation factor */     
    S->M = M;     
     
    status = ARM_MATH_SUCCESS;     
  }     
     
  return (status);     
     
}