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/*-----------------------------------------------------------------------------
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* Copyright (C) 2010 ARM Limited. All rights reserved.
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*
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* $Date: 15. July 2011
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* $Revision: V1.0.10
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*
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* Project: CMSIS DSP Library
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* Title: arm_fir_decimate_init_f32.c
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*
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* Description: Floating-point FIR Decimator initialization function.
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*
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* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
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*
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* Version 1.0.10 2011/7/15
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* Big Endian support added and Merged M0 and M3/M4 Source code.
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*
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* Version 1.0.3 2010/11/29
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* Re-organized the CMSIS folders and updated documentation.
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*
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* Version 1.0.2 2010/11/11
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* Documentation updated.
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*
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* Version 1.0.1 2010/10/05
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* Production release and review comments incorporated.
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*
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* Version 1.0.0 2010/09/20
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* Production release and review comments incorporated
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*
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* Version 0.0.7 2010/06/10
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* Misra-C changes done
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* ---------------------------------------------------------------------------*/
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#include "arm_math.h"
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/**
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* @ingroup groupFilters
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*/
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/**
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* @addtogroup FIR_decimate
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* @{
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*/
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/**
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* @brief Initialization function for the floating-point FIR decimator.
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* @param[in,out] *S points to an instance of the floating-point FIR decimator structure.
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* @param[in] numTaps number of coefficients in the filter.
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* @param[in] M decimation factor.
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* @param[in] *pCoeffs points to the filter coefficients.
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* @param[in] *pState points to the state buffer.
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* @param[in] blockSize number of input samples to process per call.
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* @return The function returns ARM_MATH_SUCCESS if initialization was successful or ARM_MATH_LENGTH_ERROR if
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* <code>blockSize</code> is not a multiple of <code>M</code>.
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*
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* <b>Description:</b>
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* \par
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* <code>pCoeffs</code> points to the array of filter coefficients stored in time reversed order:
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* <pre>
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* {b[numTaps-1], b[numTaps-2], b[N-2], ..., b[1], b[0]}
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* </pre>
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* \par
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* <code>pState</code> points to the array of state variables.
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* <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>arm_fir_decimate_f32()</code>.
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* <code>M</code> is the decimation factor.
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*/
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arm_status arm_fir_decimate_init_f32(
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arm_fir_decimate_instance_f32 * S,
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uint16_t numTaps,
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uint8_t M,
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float32_t * pCoeffs,
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float32_t * pState,
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uint32_t blockSize)
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{
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arm_status status;
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/* The size of the input block must be a multiple of the decimation factor */
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if((blockSize % M) != 0u)
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{
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/* Set status as ARM_MATH_LENGTH_ERROR */
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status = ARM_MATH_LENGTH_ERROR;
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}
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else
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{
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/* Assign filter taps */
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S->numTaps = numTaps;
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/* Assign coefficient pointer */
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S->pCoeffs = pCoeffs;
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/* Clear state buffer and size is always (blockSize + numTaps - 1) */
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memset(pState, 0, (numTaps + (blockSize - 1u)) * sizeof(float32_t));
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/* Assign state pointer */
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S->pState = pState;
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/* Assign Decimation Factor */
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S->M = M;
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status = ARM_MATH_SUCCESS;
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}
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return (status);
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}
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/**
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* @} end of FIR_decimate group
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*/
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