| /* ---------------------------------------------------------------------- |
| * Project: CMSIS DSP Library |
| * Title: arm_fir_init_q7.c |
| * Description: Q7 FIR filter initialization function |
| * |
| * $Date: 27. January 2017 |
| * $Revision: V.1.5.1 |
| * |
| * Target Processor: Cortex-M cores |
| * -------------------------------------------------------------------- */ |
| /* |
| * Copyright (C) 2010-2017 ARM Limited or its affiliates. All rights reserved. |
| * |
| * SPDX-License-Identifier: Apache-2.0 |
| * |
| * Licensed under the Apache License, Version 2.0 (the License); you may |
| * not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an AS IS BASIS, WITHOUT |
| * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| #include "arm_math.h" |
| |
| /** |
| * @ingroup groupFilters |
| */ |
| |
| /** |
| * @addtogroup FIR |
| * @{ |
| */ |
| /** |
| * @param[in,out] *S points to an instance of the Q7 FIR filter structure. |
| * @param[in] numTaps Number of filter coefficients in the filter. |
| * @param[in] *pCoeffs points to the filter coefficients buffer. |
| * @param[in] *pState points to the state buffer. |
| * @param[in] blockSize number of samples that are processed per call. |
| * @return none |
| * |
| * <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[N-2], ..., b[1], b[0]} |
| * </pre> |
| * \par |
| * <code>pState</code> points to the array of state variables. |
| * <code>pState</code> is of length <code>numTaps+blockSize-1</code> samples, where <code>blockSize</code> is the number of input samples processed by each call to <code>arm_fir_q7()</code>. |
| */ |
| |
| void arm_fir_init_q7( |
| arm_fir_instance_q7 * S, |
| uint16_t numTaps, |
| q7_t * pCoeffs, |
| q7_t * pState, |
| uint32_t blockSize) |
| { |
| |
| /* Assign filter taps */ |
| S->numTaps = numTaps; |
| |
| /* Assign coefficient pointer */ |
| S->pCoeffs = pCoeffs; |
| |
| /* Clear the state buffer. The size is always (blockSize + numTaps - 1) */ |
| memset(pState, 0, (numTaps + (blockSize - 1U)) * sizeof(q7_t)); |
| |
| /* Assign state pointer */ |
| S->pState = pState; |
| |
| } |
| |
| /** |
| * @} end of FIR group |
| */ |