1 /* ----------------------------------------------------------------------
2 * Project: CMSIS DSP Library
3 * Title: arm_cfft_radix4_init_f32.c
4 * Description: Radix-4 Decimation in Frequency Floating-point CFFT & CIFFT 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/transform_functions.h"
30 #include "arm_common_tables.h"
31
32
33 /**
34 @addtogroup ComplexFFTDeprecated
35 @{
36 */
37
38 /**
39 @brief Initialization function for the floating-point CFFT/CIFFT.
40 @deprecated Do not use this function. It has been superceded by \ref arm_cfft_f32 and will be removed in the future.
41 @param[in,out] S points to an instance of the floating-point CFFT/CIFFT structure
42 @param[in] fftLen length of the FFT
43 @param[in] ifftFlag flag that selects transform direction
44 - value = 0: forward transform
45 - value = 1: inverse transform
46 @param[in] bitReverseFlag flag that enables / disables bit reversal of output
47 - value = 0: disables bit reversal of output
48 - value = 1: enables bit reversal of output
49 @return execution status
50 - \ref ARM_MATH_SUCCESS : Operation successful
51 - \ref ARM_MATH_ARGUMENT_ERROR : <code>fftLen</code> is not a supported length
52
53 @par Details
54 The parameter <code>ifftFlag</code> controls whether a forward or inverse transform is computed.
55 Set(=1) ifftFlag for calculation of CIFFT otherwise CFFT is calculated
56 @par
57 The parameter <code>bitReverseFlag</code> controls whether output is in normal order or bit reversed order.
58 Set(=1) bitReverseFlag for output to be in normal order otherwise output is in bit reversed order.
59 @par
60 The parameter <code>fftLen</code> Specifies length of CFFT/CIFFT process. Supported FFT Lengths are 16, 64, 256, 1024.
61 @par
62 This Function also initializes Twiddle factor table pointer and Bit reversal table pointer.
63 */
64
arm_cfft_radix4_init_f32(arm_cfft_radix4_instance_f32 * S,uint16_t fftLen,uint8_t ifftFlag,uint8_t bitReverseFlag)65 arm_status arm_cfft_radix4_init_f32(
66 arm_cfft_radix4_instance_f32 * S,
67 uint16_t fftLen,
68 uint8_t ifftFlag,
69 uint8_t bitReverseFlag)
70 {
71 /* Initialise the default arm status */
72 arm_status status = ARM_MATH_ARGUMENT_ERROR;
73
74 /* Initialise the default arm status */
75 status = ARM_MATH_SUCCESS;
76
77 /* Initialise the FFT length */
78 S->fftLen = fftLen;
79
80 /* Initialise the Twiddle coefficient pointer */
81 S->pTwiddle = (float32_t *) twiddleCoef;
82
83 /* Initialise the Flag for selection of CFFT or CIFFT */
84 S->ifftFlag = ifftFlag;
85
86 /* Initialise the Flag for calculation Bit reversal or not */
87 S->bitReverseFlag = bitReverseFlag;
88
89 /* Initializations of structure parameters depending on the FFT length */
90 switch (S->fftLen)
91 {
92
93 case 4096U:
94 /* Initializations of structure parameters for 4096 point FFT */
95
96 /* Initialise the twiddle coef modifier value */
97 S->twidCoefModifier = 1U;
98 /* Initialise the bit reversal table modifier */
99 S->bitRevFactor = 1U;
100 /* Initialise the bit reversal table pointer */
101 S->pBitRevTable = (uint16_t *) armBitRevTable;
102 /* Initialise the 1/fftLen Value */
103 S->onebyfftLen = 0.000244140625;
104 break;
105
106 case 1024U:
107 /* Initializations of structure parameters for 1024 point FFT */
108
109 /* Initialise the twiddle coef modifier value */
110 S->twidCoefModifier = 4U;
111 /* Initialise the bit reversal table modifier */
112 S->bitRevFactor = 4U;
113 /* Initialise the bit reversal table pointer */
114 S->pBitRevTable = (uint16_t *) & armBitRevTable[3];
115 /* Initialise the 1/fftLen Value */
116 S->onebyfftLen = 0.0009765625f;
117 break;
118
119
120 case 256U:
121 /* Initializations of structure parameters for 256 point FFT */
122 S->twidCoefModifier = 16U;
123 S->bitRevFactor = 16U;
124 S->pBitRevTable = (uint16_t *) & armBitRevTable[15];
125 S->onebyfftLen = 0.00390625f;
126 break;
127
128 case 64U:
129 /* Initializations of structure parameters for 64 point FFT */
130 S->twidCoefModifier = 64U;
131 S->bitRevFactor = 64U;
132 S->pBitRevTable = (uint16_t *) & armBitRevTable[63];
133 S->onebyfftLen = 0.015625f;
134 break;
135
136 case 16U:
137 /* Initializations of structure parameters for 16 point FFT */
138 S->twidCoefModifier = 256U;
139 S->bitRevFactor = 256U;
140 S->pBitRevTable = (uint16_t *) & armBitRevTable[255];
141 S->onebyfftLen = 0.0625f;
142 break;
143
144
145 default:
146 /* Reporting argument error if fftSize is not valid value */
147 status = ARM_MATH_ARGUMENT_ERROR;
148 break;
149 }
150
151
152 return (status);
153 }
154
155 /**
156 @} end of ComplexFFTDeprecated group
157 */
158
