1 /* ----------------------------------------------------------------------
2  * Project:      CMSIS DSP Library
3  * Title:        arm_cfft_radix2_init_f16.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_f16.h"
30 #include "arm_common_tables.h"
31 #include "arm_common_tables_f16.h"
32 
33 
34 /**
35   @addtogroup ComplexFFTDeprecated
36   @{
37  */
38 
39 /**
40   @brief         Initialization function for the floating-point CFFT/CIFFT.
41   @deprecated    Do not use this function. It has been superseded by \ref arm_cfft_f16 and will be removed in the future.
42   @param[in,out] S              points to an instance of the floating-point CFFT/CIFFT structure
43   @param[in]     fftLen         length of the FFT
44   @param[in]     ifftFlag       flag that selects transform direction
45                    - value = 0: forward transform
46                    - value = 1: inverse transform
47   @param[in]     bitReverseFlag flag that enables / disables bit reversal of output
48                    - value = 0: disables bit reversal of output
49                    - value = 1: enables bit reversal of output
50   @return        execution status
51                    - \ref ARM_MATH_SUCCESS        : Operation successful
52                    - \ref ARM_MATH_ARGUMENT_ERROR : <code>fftLen</code> is not a supported length
53 
54   @par           Details
55                    The parameter <code>ifftFlag</code> controls whether a forward or inverse transform is computed.
56                    Set(=1) ifftFlag for calculation of CIFFT otherwise  CFFT is calculated
57   @par
58                    The parameter <code>bitReverseFlag</code> controls whether output is in normal order or bit reversed order.
59                    Set(=1) bitReverseFlag for output to be in normal order otherwise output is in bit reversed order.
60   @par
61                    The parameter <code>fftLen</code> Specifies length of CFFT/CIFFT process. Supported FFT Lengths are 16, 64, 256, 1024.
62   @par
63                    This Function also initializes Twiddle factor table pointer and Bit reversal table pointer.
64 */
65 
66 #if defined(ARM_FLOAT16_SUPPORTED)
67 
arm_cfft_radix2_init_f16(arm_cfft_radix2_instance_f16 * S,uint16_t fftLen,uint8_t ifftFlag,uint8_t bitReverseFlag)68 arm_status arm_cfft_radix2_init_f16(
69   arm_cfft_radix2_instance_f16 * 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 
78   /*  Initialise the default arm status */
79   status = ARM_MATH_SUCCESS;
80 
81   /*  Initialise the FFT length */
82   S->fftLen = fftLen;
83 
84   /*  Initialise the Twiddle coefficient pointer */
85   S->pTwiddle = (float16_t *) twiddleCoefF16_4096;
86 
87   /*  Initialise the Flag for selection of CFFT or CIFFT */
88   S->ifftFlag = ifftFlag;
89 
90   /*  Initialise the Flag for calculation Bit reversal or not */
91   S->bitReverseFlag = bitReverseFlag;
92 
93 
94   /*  Initializations of structure parameters depending on the FFT length */
95   switch (S->fftLen)
96   {
97 
98   case 4096U:
99     /*  Initializations of structure parameters for 4096 point FFT */
100 
101     /*  Initialise the twiddle coef modifier value */
102     S->twidCoefModifier = 1U;
103     /*  Initialise the bit reversal table modifier */
104     S->bitRevFactor = 1U;
105     /*  Initialise the bit reversal table pointer */
106     S->pBitRevTable = (uint16_t *) armBitRevTable;
107     /*  Initialise the 1/fftLen Value */
108     S->onebyfftLen = 0.000244140625;
109     break;
110 
111   case 2048U:
112     /*  Initializations of structure parameters for 2048 point FFT */
113 
114     /*  Initialise the twiddle coef modifier value */
115     S->twidCoefModifier = 2U;
116     /*  Initialise the bit reversal table modifier */
117     S->bitRevFactor = 2U;
118     /*  Initialise the bit reversal table pointer */
119     S->pBitRevTable = (uint16_t *) & armBitRevTable[1];
120     /*  Initialise the 1/fftLen Value */
121     S->onebyfftLen = 0.00048828125;
122     break;
123 
124   case 1024U:
125     /*  Initializations of structure parameters for 1024 point FFT */
126 
127     /*  Initialise the twiddle coef modifier value */
128     S->twidCoefModifier = 4U;
129     /*  Initialise the bit reversal table modifier */
130     S->bitRevFactor = 4U;
131     /*  Initialise the bit reversal table pointer */
132     S->pBitRevTable = (uint16_t *) & armBitRevTable[3];
133     /*  Initialise the 1/fftLen Value */
134     S->onebyfftLen = 0.0009765625f;
135     break;
136 
137   case 512U:
138     /*  Initializations of structure parameters for 512 point FFT */
139 
140     /*  Initialise the twiddle coef modifier value */
141     S->twidCoefModifier = 8U;
142     /*  Initialise the bit reversal table modifier */
143     S->bitRevFactor = 8U;
144     /*  Initialise the bit reversal table pointer */
145     S->pBitRevTable = (uint16_t *) & armBitRevTable[7];
146     /*  Initialise the 1/fftLen Value */
147     S->onebyfftLen = 0.001953125;
148     break;
149 
150   case 256U:
151     /*  Initializations of structure parameters for 256 point FFT */
152     S->twidCoefModifier = 16U;
153     S->bitRevFactor = 16U;
154     S->pBitRevTable = (uint16_t *) & armBitRevTable[15];
155     S->onebyfftLen = 0.00390625f;
156     break;
157 
158   case 128U:
159     /*  Initializations of structure parameters for 128 point FFT */
160     S->twidCoefModifier = 32U;
161     S->bitRevFactor = 32U;
162     S->pBitRevTable = (uint16_t *) & armBitRevTable[31];
163     S->onebyfftLen = 0.0078125;
164     break;
165 
166   case 64U:
167     /*  Initializations of structure parameters for 64 point FFT */
168     S->twidCoefModifier = 64U;
169     S->bitRevFactor = 64U;
170     S->pBitRevTable = (uint16_t *) & armBitRevTable[63];
171     S->onebyfftLen = 0.015625f;
172     break;
173 
174   case 32U:
175     /*  Initializations of structure parameters for 64 point FFT */
176     S->twidCoefModifier = 128U;
177     S->bitRevFactor = 128U;
178     S->pBitRevTable = (uint16_t *) & armBitRevTable[127];
179     S->onebyfftLen = 0.03125;
180     break;
181 
182   case 16U:
183     /*  Initializations of structure parameters for 16 point FFT */
184     S->twidCoefModifier = 256U;
185     S->bitRevFactor = 256U;
186     S->pBitRevTable = (uint16_t *) & armBitRevTable[255];
187     S->onebyfftLen = 0.0625f;
188     break;
189 
190 
191   default:
192     /*  Reporting argument error if fftSize is not valid value */
193     status = ARM_MATH_ARGUMENT_ERROR;
194     break;
195   }
196 
197 
198   return (status);
199 }
200 
201 #endif /* #if defined(ARM_FLOAT16_SUPPORTED) */
202 /**
203   @} end of ComplexFFTDeprecated group
204  */
205