1 /* ----------------------------------------------------------------------
2  * Project:      CMSIS DSP Library
3  * Title:        arm_cfft_radix2_init_f32.c
4  * Description:  Radix-2 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   @addtogroup ComplexFFTDeprecated
34   @{
35  */
36 
37 /**
38   @brief         Initialization function for the floating-point CFFT/CIFFT.
39   @deprecated    Do not use this function. It has been superseded by \ref arm_cfft_f32 and will be removed in the future.
40   @param[in,out] S              points to an instance of the floating-point CFFT/CIFFT structure
41   @param[in]     fftLen         length of the FFT
42   @param[in]     ifftFlag       flag that selects transform direction
43                    - value = 0: forward transform
44                    - value = 1: inverse transform
45   @param[in]     bitReverseFlag flag that enables / disables bit reversal of output
46                    - value = 0: disables bit reversal of output
47                    - value = 1: enables bit reversal of output
48   @return        execution status
49                    - \ref ARM_MATH_SUCCESS        : Operation successful
50                    - \ref ARM_MATH_ARGUMENT_ERROR : <code>fftLen</code> is not a supported length
51 
52   @par           Details
53                    The parameter <code>ifftFlag</code> controls whether a forward or inverse transform is computed.
54                    Set(=1) ifftFlag for calculation of CIFFT otherwise  CFFT is calculated
55   @par
56                    The parameter <code>bitReverseFlag</code> controls whether output is in normal order or bit reversed order.
57                    Set(=1) bitReverseFlag for output to be in normal order otherwise output is in bit reversed order.
58   @par
59                    The parameter <code>fftLen</code> Specifies length of CFFT/CIFFT process. Supported FFT Lengths are 16, 64, 256, 1024.
60   @par
61                    This Function also initializes Twiddle factor table pointer and Bit reversal table pointer.
62 */
63 
arm_cfft_radix2_init_f32(arm_cfft_radix2_instance_f32 * S,uint16_t fftLen,uint8_t ifftFlag,uint8_t bitReverseFlag)64 arm_status arm_cfft_radix2_init_f32(
65   arm_cfft_radix2_instance_f32 * S,
66   uint16_t fftLen,
67   uint8_t ifftFlag,
68   uint8_t bitReverseFlag)
69 {
70    /*  Initialise the default arm status */
71   arm_status status = ARM_MATH_ARGUMENT_ERROR;
72 
73   /*  Initialise the default arm status */
74   status = ARM_MATH_SUCCESS;
75 
76   /*  Initialise the FFT length */
77   S->fftLen = fftLen;
78 
79   /*  Initialise the Twiddle coefficient pointer */
80   S->pTwiddle = (float32_t *) twiddleCoef;
81 
82   /*  Initialise the Flag for selection of CFFT or CIFFT */
83   S->ifftFlag = ifftFlag;
84 
85   /*  Initialise the Flag for calculation Bit reversal or not */
86   S->bitReverseFlag = bitReverseFlag;
87 
88   /*  Initializations of structure parameters depending on the FFT length */
89   switch (S->fftLen)
90   {
91 
92   case 4096U:
93     /*  Initializations of structure parameters for 4096 point FFT */
94 
95     /*  Initialise the twiddle coef modifier value */
96     S->twidCoefModifier = 1U;
97     /*  Initialise the bit reversal table modifier */
98     S->bitRevFactor = 1U;
99     /*  Initialise the bit reversal table pointer */
100     S->pBitRevTable = (uint16_t *) armBitRevTable;
101     /*  Initialise the 1/fftLen Value */
102     S->onebyfftLen = 0.000244140625;
103     break;
104 
105   case 2048U:
106     /*  Initializations of structure parameters for 2048 point FFT */
107 
108     /*  Initialise the twiddle coef modifier value */
109     S->twidCoefModifier = 2U;
110     /*  Initialise the bit reversal table modifier */
111     S->bitRevFactor = 2U;
112     /*  Initialise the bit reversal table pointer */
113     S->pBitRevTable = (uint16_t *) & armBitRevTable[1];
114     /*  Initialise the 1/fftLen Value */
115     S->onebyfftLen = 0.00048828125;
116     break;
117 
118   case 1024U:
119     /*  Initializations of structure parameters for 1024 point FFT */
120 
121     /*  Initialise the twiddle coef modifier value */
122     S->twidCoefModifier = 4U;
123     /*  Initialise the bit reversal table modifier */
124     S->bitRevFactor = 4U;
125     /*  Initialise the bit reversal table pointer */
126     S->pBitRevTable = (uint16_t *) & armBitRevTable[3];
127     /*  Initialise the 1/fftLen Value */
128     S->onebyfftLen = 0.0009765625f;
129     break;
130 
131   case 512U:
132     /*  Initializations of structure parameters for 512 point FFT */
133 
134     /*  Initialise the twiddle coef modifier value */
135     S->twidCoefModifier = 8U;
136     /*  Initialise the bit reversal table modifier */
137     S->bitRevFactor = 8U;
138     /*  Initialise the bit reversal table pointer */
139     S->pBitRevTable = (uint16_t *) & armBitRevTable[7];
140     /*  Initialise the 1/fftLen Value */
141     S->onebyfftLen = 0.001953125;
142     break;
143 
144   case 256U:
145     /*  Initializations of structure parameters for 256 point FFT */
146     S->twidCoefModifier = 16U;
147     S->bitRevFactor = 16U;
148     S->pBitRevTable = (uint16_t *) & armBitRevTable[15];
149     S->onebyfftLen = 0.00390625f;
150     break;
151 
152   case 128U:
153     /*  Initializations of structure parameters for 128 point FFT */
154     S->twidCoefModifier = 32U;
155     S->bitRevFactor = 32U;
156     S->pBitRevTable = (uint16_t *) & armBitRevTable[31];
157     S->onebyfftLen = 0.0078125;
158     break;
159 
160   case 64U:
161     /*  Initializations of structure parameters for 64 point FFT */
162     S->twidCoefModifier = 64U;
163     S->bitRevFactor = 64U;
164     S->pBitRevTable = (uint16_t *) & armBitRevTable[63];
165     S->onebyfftLen = 0.015625f;
166     break;
167 
168   case 32U:
169     /*  Initializations of structure parameters for 64 point FFT */
170     S->twidCoefModifier = 128U;
171     S->bitRevFactor = 128U;
172     S->pBitRevTable = (uint16_t *) & armBitRevTable[127];
173     S->onebyfftLen = 0.03125;
174     break;
175 
176   case 16U:
177     /*  Initializations of structure parameters for 16 point FFT */
178     S->twidCoefModifier = 256U;
179     S->bitRevFactor = 256U;
180     S->pBitRevTable = (uint16_t *) & armBitRevTable[255];
181     S->onebyfftLen = 0.0625f;
182     break;
183 
184 
185   default:
186     /*  Reporting argument error if fftSize is not valid value */
187     status = ARM_MATH_ARGUMENT_ERROR;
188     break;
189   }
190 
191   return (status);
192 }
193 
194 /**
195   @} end of ComplexFFTDeprecated group
196  */
197