1 /* ----------------------------------------------------------------------
2 * Project: CMSIS DSP Library
3 * Title: arm_cfft_radix4_init_f16.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_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 It has been superceded by \ref arm_cfft_f16 and will be removed in the future.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_radix4_init_f16(arm_cfft_radix4_instance_f16 * S,uint16_t fftLen,uint8_t ifftFlag,uint8_t bitReverseFlag)68 ARM_DSP_ATTRIBUTE arm_status arm_cfft_radix4_init_f16(
69 arm_cfft_radix4_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 /* Initialise the default arm status */
78 status = ARM_MATH_SUCCESS;
79
80 /* Initialise the FFT length */
81 S->fftLen = fftLen;
82
83 /* Initialise the Twiddle coefficient pointer */
84 S->pTwiddle = (float16_t *) twiddleCoefF16;
85
86 /* Initialise the Flag for selection of CFFT or CIFFT */
87 S->ifftFlag = ifftFlag;
88
89 /* Initialise the Flag for calculation Bit reversal or not */
90 S->bitReverseFlag = bitReverseFlag;
91
92 /* Initializations of structure parameters depending on the FFT length */
93 switch (S->fftLen)
94 {
95
96 case 4096U:
97 /* Initializations of structure parameters for 4096 point FFT */
98
99 /* Initialise the twiddle coef modifier value */
100 S->twidCoefModifier = 1U;
101 /* Initialise the bit reversal table modifier */
102 S->bitRevFactor = 1U;
103 /* Initialise the bit reversal table pointer */
104 S->pBitRevTable = (uint16_t *) armBitRevTable;
105 /* Initialise the 1/fftLen Value */
106 S->onebyfftLen = 0.000244140625;
107 break;
108
109 case 1024U:
110 /* Initializations of structure parameters for 1024 point FFT */
111
112 /* Initialise the twiddle coef modifier value */
113 S->twidCoefModifier = 4U;
114 /* Initialise the bit reversal table modifier */
115 S->bitRevFactor = 4U;
116 /* Initialise the bit reversal table pointer */
117 S->pBitRevTable = (uint16_t *) & armBitRevTable[3];
118 /* Initialise the 1/fftLen Value */
119 S->onebyfftLen = 0.0009765625f;
120 break;
121
122
123 case 256U:
124 /* Initializations of structure parameters for 256 point FFT */
125 S->twidCoefModifier = 16U;
126 S->bitRevFactor = 16U;
127 S->pBitRevTable = (uint16_t *) & armBitRevTable[15];
128 S->onebyfftLen = 0.00390625f;
129 break;
130
131 case 64U:
132 /* Initializations of structure parameters for 64 point FFT */
133 S->twidCoefModifier = 64U;
134 S->bitRevFactor = 64U;
135 S->pBitRevTable = (uint16_t *) & armBitRevTable[63];
136 S->onebyfftLen = 0.015625f;
137 break;
138
139 case 16U:
140 /* Initializations of structure parameters for 16 point FFT */
141 S->twidCoefModifier = 256U;
142 S->bitRevFactor = 256U;
143 S->pBitRevTable = (uint16_t *) & armBitRevTable[255];
144 S->onebyfftLen = 0.0625f;
145 break;
146
147
148 default:
149 /* Reporting argument error if fftSize is not valid value */
150 status = ARM_MATH_ARGUMENT_ERROR;
151 break;
152 }
153
154 return (status);
155 }
156 #endif /* #if defined(ARM_FLOAT16_SUPPORTED) */
157 /**
158 @} end of ComplexFFTDeprecated group
159 */
160
