1 /* ----------------------------------------------------------------------
2 * Project: CMSIS DSP Library
3 * Title: arm_cfft_radix2_init_q15.c
4 * Description: Radix-2 Decimation in Frequency Q15 FFT & IFFT 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 /**
38 @addtogroup ComplexFFT
39 @{
40 */
41
42 /**
43 @brief Initialization function for the Q15 CFFT/CIFFT.
44 @deprecated Do not use this function. It has been superseded by \ref arm_cfft_q15 and will be removed
45 @param[in,out] S points to an instance of the Q15 CFFT/CIFFT structure.
46 @param[in] fftLen length of the FFT.
47 @param[in] ifftFlag flag that selects transform direction
48 - value = 0: forward transform
49 - value = 1: inverse transform
50 @param[in] bitReverseFlag flag that enables / disables bit reversal of output
51 - value = 0: disables bit reversal of output
52 - value = 1: enables bit reversal of output
53 @return execution status
54 - \ref ARM_MATH_SUCCESS : Operation successful
55 - \ref ARM_MATH_ARGUMENT_ERROR : <code>fftLen</code> is not a supported length
56
57 @par Details
58 The parameter <code>ifftFlag</code> controls whether a forward or inverse transform is computed.
59 Set(=1) ifftFlag for calculation of CIFFT otherwise CFFT is calculated
60 @par
61 The parameter <code>bitReverseFlag</code> controls whether output is in normal order or bit reversed order.
62 Set(=1) bitReverseFlag for output to be in normal order otherwise output is in bit reversed order.
63 @par
64 The parameter <code>fftLen</code> Specifies length of CFFT/CIFFT process. Supported FFT Lengths are 16, 64, 256, 1024.
65 @par
66 This Function also initializes Twiddle factor table pointer and Bit reversal table pointer.
67 */
68
arm_cfft_radix2_init_q15(arm_cfft_radix2_instance_q15 * S,uint16_t fftLen,uint8_t ifftFlag,uint8_t bitReverseFlag)69 arm_status arm_cfft_radix2_init_q15(
70 arm_cfft_radix2_instance_q15 * S,
71 uint16_t fftLen,
72 uint8_t ifftFlag,
73 uint8_t bitReverseFlag)
74 {
75 /* Initialise the default arm status */
76 arm_status status = ARM_MATH_ARGUMENT_ERROR;
77
78 #if !defined(ARM_DSP_CONFIG_TABLES) || defined(ARM_FFT_ALLOW_TABLES)
79
80 #if !defined(ARM_DSP_CONFIG_TABLES) || defined(ARM_ALL_FFT_TABLES) || defined(ARM_TABLE_TWIDDLECOEF_Q15_4096)
81
82 /* Initialise the default arm status */
83 status = ARM_MATH_SUCCESS;
84
85 /* Initialise the FFT length */
86 S->fftLen = fftLen;
87
88 /* Initialise the Twiddle coefficient pointer */
89 S->pTwiddle = (q15_t *) twiddleCoef_4096_q15;
90 /* Initialise the Flag for selection of CFFT or CIFFT */
91 S->ifftFlag = ifftFlag;
92 /* Initialise the Flag for calculation Bit reversal or not */
93 S->bitReverseFlag = bitReverseFlag;
94
95 #if !defined(ARM_DSP_CONFIG_TABLES) || defined(ARM_ALL_FFT_TABLES) || defined(ARM_TABLE_BITREV_1024)
96
97 /* Initializations of structure parameters depending on the FFT length */
98 switch (S->fftLen)
99 {
100 case 4096U:
101 /* Initializations of structure parameters for 4096 point FFT */
102
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
110 break;
111
112 case 2048U:
113 /* Initializations of structure parameters for 2048 point FFT */
114
115 /* Initialise the twiddle coef modifier value */
116 S->twidCoefModifier = 2U;
117 /* Initialise the bit reversal table modifier */
118 S->bitRevFactor = 2U;
119 /* Initialise the bit reversal table pointer */
120 S->pBitRevTable = (uint16_t *) & armBitRevTable[1];
121
122 break;
123
124 case 1024U:
125 /* Initializations of structure parameters for 1024 point FFT */
126 S->twidCoefModifier = 4U;
127 S->bitRevFactor = 4U;
128 S->pBitRevTable = (uint16_t *) & armBitRevTable[3];
129
130 break;
131
132 case 512U:
133 /* Initializations of structure parameters for 512 point FFT */
134 S->twidCoefModifier = 8U;
135 S->bitRevFactor = 8U;
136 S->pBitRevTable = (uint16_t *) & armBitRevTable[7];
137
138 break;
139
140 case 256U:
141 /* Initializations of structure parameters for 256 point FFT */
142 S->twidCoefModifier = 16U;
143 S->bitRevFactor = 16U;
144 S->pBitRevTable = (uint16_t *) & armBitRevTable[15];
145
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
154 break;
155
156 case 64U:
157 /* Initializations of structure parameters for 64 point FFT */
158 S->twidCoefModifier = 64U;
159 S->bitRevFactor = 64U;
160 S->pBitRevTable = (uint16_t *) & armBitRevTable[63];
161
162 break;
163
164 case 32U:
165 /* Initializations of structure parameters for 32 point FFT */
166 S->twidCoefModifier = 128U;
167 S->bitRevFactor = 128U;
168 S->pBitRevTable = (uint16_t *) & armBitRevTable[127];
169
170 break;
171
172 case 16U:
173 /* Initializations of structure parameters for 16 point FFT */
174 S->twidCoefModifier = 256U;
175 S->bitRevFactor = 256U;
176 S->pBitRevTable = (uint16_t *) & armBitRevTable[255];
177
178 break;
179
180 default:
181 /* Reporting argument error if fftSize is not valid value */
182 status = ARM_MATH_ARGUMENT_ERROR;
183 break;
184 }
185
186 #endif
187 #endif
188 #endif
189 return (status);
190 }
191
192 /**
193 @} end of ComplexFFT group
194 */
195
