CMSIS DSP library
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cmsis_dsp/FilteringFunctions/arm_fir_interpolate_init_q15.c
- Committer:
- mbed_official
- Date:
- 2013-11-08
- Revision:
- 3:7a284390b0ce
- Parent:
- 2:da51fb522205
- Child:
- 5:3762170b6d4d
File content as of revision 3:7a284390b0ce:
/*----------------------------------------------------------------------------- * Copyright (C) 2010-2013 ARM Limited. All rights reserved. * * $Date: 17. January 2013 * $Revision: V1.4.1 * * Project: CMSIS DSP Library * Title: arm_fir_interpolate_init_q15.c * * Description: Q15 FIR interpolator 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. * ---------------------------------------------------------------------------*/ #include "arm_math.h" /** * @ingroup groupFilters */ /** * @addtogroup FIR_Interpolate * @{ */ /** * @brief Initialization function for the Q15 FIR interpolator. * @param[in,out] *S points to an instance of the Q15 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_q15()</code>. */ arm_status arm_fir_interpolate_init_q15( arm_fir_interpolate_instance_q15 * S, uint8_t L, uint16_t numTaps, q15_t * pCoeffs, q15_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(q15_t)); /* Assign state pointer */ S->pState = pState; status = ARM_MATH_SUCCESS; } return (status); } /** * @} end of FIR_Interpolate group */