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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_interpolate_init_q31.c
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*
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* Description: Q31 FIR interpolator 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_Interpolate
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* @{
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*/
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/**
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* @brief Initialization function for the Q31 FIR interpolator.
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* @param[in,out] *S points to an instance of the Q31 FIR interpolator structure.
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* @param[in] L upsample factor.
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* @param[in] numTaps number of filter coefficients in the filter.
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* @param[in] *pCoeffs points to the filter coefficient buffer.
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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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* the filter length <code>numTaps</code> is not a multiple of the interpolation factor <code>L</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[numTaps-2], ..., b[1], b[0]}
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* </pre>
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* The length of the filter <code>numTaps</code> must be a multiple of the interpolation factor <code>L</code>.
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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/L)+blockSize-1</code> words
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* where <code>blockSize</code> is the number of input samples processed by each call to <code>arm_fir_interpolate_q31()</code>.
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*/
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arm_status arm_fir_interpolate_init_q31(
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arm_fir_interpolate_instance_q31 * S,
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uint8_t L,
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uint16_t numTaps,
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q31_t * pCoeffs,
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q31_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 filter length must be a multiple of the interpolation factor */
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if((numTaps % L) != 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 coefficient pointer */
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S->pCoeffs = pCoeffs;
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/* Assign Interpolation factor */
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S->L = L;
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/* Assign polyPhaseLength */
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S->phaseLength = numTaps / L;
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/* Clear state buffer and size of buffer is always phaseLength + blockSize - 1 */
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memset(pState, 0,
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(blockSize + ((uint32_t) S->phaseLength - 1u)) * sizeof(q31_t));
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/* Assign state pointer */
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S->pState = pState;
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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_Interpolate group
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*/
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