arm_fir_interpolate_init_q31.c
113 lines
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CLexer
r71 | /*----------------------------------------------------------------------------- | |||
* Copyright (C) 2010 ARM Limited. All rights reserved. | ||||
* | ||||
* $Date: 15. July 2011 | ||||
* $Revision: V1.0.10 | ||||
* | ||||
* Project: CMSIS DSP Library | ||||
* Title: arm_fir_interpolate_init_q31.c | ||||
* | ||||
* Description: Q31 FIR interpolator initialization function | ||||
* | ||||
* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0 | ||||
* | ||||
* Version 1.0.10 2011/7/15 | ||||
* Big Endian support added and Merged M0 and M3/M4 Source code. | ||||
* | ||||
* Version 1.0.3 2010/11/29 | ||||
* Re-organized the CMSIS folders and updated documentation. | ||||
* | ||||
* Version 1.0.2 2010/11/11 | ||||
* Documentation updated. | ||||
* | ||||
* Version 1.0.1 2010/10/05 | ||||
* Production release and review comments incorporated. | ||||
* | ||||
* Version 1.0.0 2010/09/20 | ||||
* Production release and review comments incorporated | ||||
* | ||||
* Version 0.0.7 2010/06/10 | ||||
* Misra-C changes done | ||||
* ---------------------------------------------------------------------------*/ | ||||
#include "arm_math.h" | ||||
/** | ||||
* @ingroup groupFilters | ||||
*/ | ||||
/** | ||||
* @addtogroup FIR_Interpolate | ||||
* @{ | ||||
*/ | ||||
/** | ||||
* @brief Initialization function for the Q31 FIR interpolator. | ||||
* @param[in,out] *S points to an instance of the Q31 FIR interpolator structure. | ||||
* @param[in] L upsample factor. | ||||
* @param[in] numTaps number of filter coefficients in the filter. | ||||
* @param[in] *pCoeffs points to the filter coefficient buffer. | ||||
* @param[in] *pState points to the state buffer. | ||||
* @param[in] blockSize number of input samples to process per call. | ||||
* @return The function returns ARM_MATH_SUCCESS if initialization was successful or ARM_MATH_LENGTH_ERROR if | ||||
* the filter length <code>numTaps</code> is not a multiple of the interpolation factor <code>L</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[numTaps-2], ..., b[1], b[0]} | ||||
* </pre> | ||||
* The length of the filter <code>numTaps</code> must be a multiple of the interpolation factor <code>L</code>. | ||||
* \par | ||||
* <code>pState</code> points to the array of state variables. | ||||
* <code>pState</code> is of length <code>(numTaps/L)+blockSize-1</code> words | ||||
* where <code>blockSize</code> is the number of input samples processed by each call to <code>arm_fir_interpolate_q31()</code>. | ||||
*/ | ||||
arm_status arm_fir_interpolate_init_q31( | ||||
arm_fir_interpolate_instance_q31 * S, | ||||
uint8_t L, | ||||
uint16_t numTaps, | ||||
q31_t * pCoeffs, | ||||
q31_t * pState, | ||||
uint32_t blockSize) | ||||
{ | ||||
arm_status status; | ||||
/* The filter length must be a multiple of the interpolation factor */ | ||||
if((numTaps % L) != 0u) | ||||
{ | ||||
/* Set status as ARM_MATH_LENGTH_ERROR */ | ||||
status = ARM_MATH_LENGTH_ERROR; | ||||
} | ||||
else | ||||
{ | ||||
/* Assign coefficient pointer */ | ||||
S->pCoeffs = pCoeffs; | ||||
/* Assign Interpolation factor */ | ||||
S->L = L; | ||||
/* Assign polyPhaseLength */ | ||||
S->phaseLength = numTaps / L; | ||||
/* Clear state buffer and size of buffer is always phaseLength + blockSize - 1 */ | ||||
memset(pState, 0, | ||||
(blockSize + ((uint32_t) S->phaseLength - 1u)) * sizeof(q31_t)); | ||||
/* Assign state pointer */ | ||||
S->pState = pState; | ||||
status = ARM_MATH_SUCCESS; | ||||
} | ||||
return (status); | ||||
} | ||||
/** | ||||
* @} end of FIR_Interpolate group | ||||
*/ | ||||