1 /* ----------------------------------------------------------------------
2 * Project: CMSIS DSP Library
3 * Title: arm_cfft_radix2_init_q31.c
4 * Description: Radix-2 Decimation in Frequency Fixed-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 @ingroup groupTransforms
34 */
35
36 /**
37 @addtogroup ComplexFFT
38 @{
39 */
40
41 /**
42 @brief Initialization function for the Q31 CFFT/CIFFT.
43 @deprecated Do not use this function. It has been superseded by \ref arm_cfft_q31 and will be removed in the future.
44 @param[in,out] S points to an instance of the Q31 CFFT/CIFFT structure
45 @param[in] fftLen length of the FFT
46 @param[in] ifftFlag flag that selects transform direction
47 - value = 0: forward transform
48 - value = 1: inverse transform
49 @param[in] bitReverseFlag flag that enables / disables bit reversal of output
50 - value = 0: disables bit reversal of output
51 - value = 1: enables bit reversal of output
52 @return execution status
53 - \ref ARM_MATH_SUCCESS : Operation successful
54 - \ref ARM_MATH_ARGUMENT_ERROR : <code>fftLen</code> is not a supported length
55
56 @par Details
57 The parameter <code>ifftFlag</code> controls whether a forward or inverse transform is computed.
58 Set(=1) ifftFlag for calculation of CIFFT otherwise CFFT is calculated
59 @par
60 The parameter <code>bitReverseFlag</code> controls whether output is in normal order or bit reversed order.
61 Set(=1) bitReverseFlag for output to be in normal order otherwise output is in bit reversed order.
62 @par
63 The parameter <code>fftLen</code> Specifies length of CFFT/CIFFT process. Supported FFT Lengths are 16, 64, 256, 1024.
64 @par
65 This Function also initializes Twiddle factor table pointer and Bit reversal table pointer.
66 */
67
arm_cfft_radix2_init_q31(arm_cfft_radix2_instance_q31 * S,uint16_t fftLen,uint8_t ifftFlag,uint8_t bitReverseFlag)68 arm_status arm_cfft_radix2_init_q31(
69 arm_cfft_radix2_instance_q31 * S,
70 uint16_t fftLen,
71 uint8_t ifftFlag,
72 uint8_t bitReverseFlag)
73 {
74 /* Initialise the default arm status */
75 arm_status status = ARM_MATH_ARGUMENT_ERROR;
76
77 #if !defined(ARM_DSP_CONFIG_TABLES) || defined(ARM_FFT_ALLOW_TABLES)
78
79 #if !defined(ARM_DSP_CONFIG_TABLES) || defined(ARM_ALL_FFT_TABLES) || defined(ARM_TABLE_TWIDDLECOEF_Q31_4096)
80
81 /* Initialise the default arm status */
82 status = ARM_MATH_SUCCESS;
83
84 /* Initialise the FFT length */
85 S->fftLen = fftLen;
86
87 /* Initialise the Twiddle coefficient pointer */
88 S->pTwiddle = (q31_t *) twiddleCoef_4096_q31;
89
90 /* Initialise the Flag for selection of CFFT or CIFFT */
91 S->ifftFlag = ifftFlag;
92
93 /* Initialise the Flag for calculation Bit reversal or not */
94 S->bitReverseFlag = bitReverseFlag;
95
96 #if !defined(ARM_DSP_CONFIG_TABLES) || defined(ARM_ALL_FFT_TABLES) || defined(ARM_TABLE_BITREV_1024)
97
98 /* Initializations of Instance structure depending on the FFT length */
99 switch (S->fftLen)
100 {
101 /* Initializations of structure parameters for 4096 point FFT */
102 case 4096U:
103 /* Initialise the twiddle coef modifier value */
104 S->twidCoefModifier = 1U;
105 /* Initialise the bit reversal table modifier */
106 S->bitRevFactor = 1U;
107 /* Initialise the bit reversal table pointer */
108 S->pBitRevTable = (uint16_t *) armBitRevTable;
109 break;
110
111 /* Initializations of structure parameters for 2048 point FFT */
112 case 2048U:
113 /* Initialise the twiddle coef modifier value */
114 S->twidCoefModifier = 2U;
115 /* Initialise the bit reversal table modifier */
116 S->bitRevFactor = 2U;
117 /* Initialise the bit reversal table pointer */
118 S->pBitRevTable = (uint16_t *) & armBitRevTable[1];
119 break;
120
121 /* Initializations of structure parameters for 1024 point FFT */
122 case 1024U:
123 /* Initialise the twiddle coef modifier value */
124 S->twidCoefModifier = 4U;
125 /* Initialise the bit reversal table modifier */
126 S->bitRevFactor = 4U;
127 /* Initialise the bit reversal table pointer */
128 S->pBitRevTable = (uint16_t *) & armBitRevTable[3];
129 break;
130
131 /* Initializations of structure parameters for 512 point FFT */
132 case 512U:
133 /* Initialise the twiddle coef modifier value */
134 S->twidCoefModifier = 8U;
135 /* Initialise the bit reversal table modifier */
136 S->bitRevFactor = 8U;
137 /* Initialise the bit reversal table pointer */
138 S->pBitRevTable = (uint16_t *) & armBitRevTable[7];
139 break;
140
141 case 256U:
142 /* Initializations of structure parameters for 256 point FFT */
143 S->twidCoefModifier = 16U;
144 S->bitRevFactor = 16U;
145 S->pBitRevTable = (uint16_t *) & armBitRevTable[15];
146 break;
147
148 case 128U:
149 /* Initializations of structure parameters for 128 point FFT */
150 S->twidCoefModifier = 32U;
151 S->bitRevFactor = 32U;
152 S->pBitRevTable = (uint16_t *) & armBitRevTable[31];
153 break;
154
155 case 64U:
156 /* Initializations of structure parameters for 64 point FFT */
157 S->twidCoefModifier = 64U;
158 S->bitRevFactor = 64U;
159 S->pBitRevTable = (uint16_t *) & armBitRevTable[63];
160 break;
161
162 case 32U:
163 /* Initializations of structure parameters for 32 point FFT */
164 S->twidCoefModifier = 128U;
165 S->bitRevFactor = 128U;
166 S->pBitRevTable = (uint16_t *) & armBitRevTable[127];
167 break;
168
169 case 16U:
170 /* Initializations of structure parameters for 16 point FFT */
171 S->twidCoefModifier = 256U;
172 S->bitRevFactor = 256U;
173 S->pBitRevTable = (uint16_t *) & armBitRevTable[255];
174 break;
175
176
177 default:
178 /* Reporting argument error if fftSize is not valid value */
179 status = ARM_MATH_ARGUMENT_ERROR;
180 break;
181 }
182
183 #endif
184 #endif
185 #endif
186 return (status);
187 }
188
189 /**
190 @} end of ComplexFFT group
191 */
192