| /*----------------------------------------------------------------------------- |
| * 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_f32.c |
| * |
| * Description: Floating-point 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 floating-point FIR interpolator. |
| * @param[in,out] *S points to an instance of the floating-point 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_f32()</code>. |
| */ |
| |
| arm_status arm_fir_interpolate_init_f32( |
| arm_fir_interpolate_instance_f32 * S, |
| uint8_t L, |
| uint16_t numTaps, |
| float32_t * pCoeffs, |
| float32_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 state array is always phaseLength + blockSize - 1 */ |
| memset(pState, 0, |
| (blockSize + |
| ((uint32_t) S->phaseLength - 1u)) * sizeof(float32_t)); |
| |
| /* Assign state pointer */ |
| S->pState = pState; |
| |
| status = ARM_MATH_SUCCESS; |
| } |
| |
| return (status); |
| |
| } |
| |
| /** |
| * @} end of FIR_Interpolate group |
| */ |
