text: /*-----------------------------------------------------------------------------    
  * 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_f32.c    
  *    
  * Description:  Floating-point FIR Decimator 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
  * are met:
  *   - Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  *   - Redistributions in binary form must reproduce the above copyright
  *     notice, this list of conditions and the following disclaimer in
  *     the documentation and/or other materials provided with the 
  *     distribution.
  *   - 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
  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 
  * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
  * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  * POSSIBILITY OF SUCH DAMAGE.  
  
   Modifications 2017  Mostafa Saleh       (Ported to RISC-V PULPino) 
  * ---------------------------------------------------------------------------*/
  
  #include <riscv_dsp/riscv_math.h>
  
  /**    
   * @ingroup groupFilters    
   */
  
  /**    
   * @addtogroup FIR_decimate    
   * @{    
   */
  
  /**    
   * @brief  Initialization function for the floating-point FIR decimator.    
   * @param[in,out] *S points to an instance of the floating-point FIR decimator structure.    
   * @param[in] numTaps  number of coefficients in the filter.    
   * @param[in] M  decimation factor.    
   * @param[in] *pCoeffs points to the filter coefficients.    
   * @param[in] *pState points to the state buffer.    
   * @param[in] blockSize number of input samples to process per call.    
   * @return    The function returns RISCV_MATH_SUCCESS if initialization was successful or RISCV_MATH_LENGTH_ERROR if    
   * <code>blockSize</code> is not a multiple of <code>M</code>.    
   *    
   * <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>    
   * \par    
   * <code>pState</code> points to the array of state variables.    
   * <code>pState</code> is of length <code>numTaps+blockSize-1</code> words where <code>blockSize</code> is the number of input samples passed to <code>riscv_fir_decimate_f32()</code>.    
   * <code>M</code> is the decimation factor.    
   */
  
  riscv_status riscv_fir_decimate_init_f32(
    riscv_fir_decimate_instance_f32 * S,
    uint16_t numTaps,
    uint8_t M,
    float32_t * pCoeffs,
    float32_t * pState,
    uint32_t blockSize)
  {
    riscv_status status;
  
    /* The size of the input block must be a multiple of the decimation factor */
    if((blockSize % M) != 0u)
    {
      /* Set status as RISCV_MATH_LENGTH_ERROR */
      status = RISCV_MATH_LENGTH_ERROR;
    }
    else
    {
      /* 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(float32_t));
  
      /* Assign state pointer */
      S->pState = pState;
  
      /* Assign Decimation Factor */
      S->M = M;
  
      status = RISCV_MATH_SUCCESS;
    }
  
    return (status);
  
  }
  
  /**    
   * @} end of FIR_decimate group    
   */
  