1 /* ----------------------------------------------------------------------
2 * Project: CMSIS DSP Library
3 * Title: arm_iir_lattice_init_f32.c
4 * Description: Floating-point IIR lattice filter initialization function
5 *
6 * $Date: 23 April 2021
7 * $Revision: V1.9.0
8 *
9 * Target Processor: Cortex-M and Cortex-A cores
10 * -------------------------------------------------------------------- */
11 /*
12 * Copyright (C) 2010-2021 ARM Limited or its affiliates. All rights reserved.
13 *
14 * SPDX-License-Identifier: Apache-2.0
15 *
16 * Licensed under the Apache License, Version 2.0 (the License); you may
17 * not use this file except in compliance with the License.
18 * You may obtain a copy of the License at
19 *
20 * www.apache.org/licenses/LICENSE-2.0
21 *
22 * Unless required by applicable law or agreed to in writing, software
23 * distributed under the License is distributed on an AS IS BASIS, WITHOUT
24 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
25 * See the License for the specific language governing permissions and
26 * limitations under the License.
27 */
28
29 #include "dsp/filtering_functions.h"
30
31 /**
32 @ingroup groupFilters
33 */
34
35 /**
36 @addtogroup IIR_Lattice
37 @{
38 */
39
40 /**
41 @brief Initialization function for the floating-point IIR lattice filter.
42 @param[in] S points to an instance of the floating-point IIR lattice structure
43 @param[in] numStages number of stages in the filter
44 @param[in] pkCoeffs points to reflection coefficient buffer. The array is of length numStages
45 @param[in] pvCoeffs points to ladder coefficient buffer. The array is of length numStages+1
46 @param[in] pState points to state buffer. The array is of length numStages+blockSize
47 @param[in] blockSize number of samples to process
48 */
49
arm_iir_lattice_init_f32(arm_iir_lattice_instance_f32 * S,uint16_t numStages,float32_t * pkCoeffs,float32_t * pvCoeffs,float32_t * pState,uint32_t blockSize)50 void arm_iir_lattice_init_f32(
51 arm_iir_lattice_instance_f32 * S,
52 uint16_t numStages,
53 float32_t * pkCoeffs,
54 float32_t * pvCoeffs,
55 float32_t * pState,
56 uint32_t blockSize)
57 {
58 /* Assign filter taps */
59 S->numStages = numStages;
60
61 /* Assign reflection coefficient pointer */
62 S->pkCoeffs = pkCoeffs;
63
64 /* Assign ladder coefficient pointer */
65 S->pvCoeffs = pvCoeffs;
66
67 /* Clear state buffer and size is always blockSize + numStages */
68 memset(pState, 0, (numStages + blockSize) * sizeof(float32_t));
69
70 /* Assign state pointer */
71 S->pState = pState;
72 }
73
74 /**
75 @} end of IIR_Lattice group
76 */
77
