1 /* ----------------------------------------------------------------------
2 * Project: CMSIS DSP Library
3 * Title: arm_cfft_radix4_init_q15.c
4 * Description: Radix-4 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 /**
44 @brief Initialization function for the Q15 CFFT/CIFFT.
45 @deprecated Do not use this function. It has been superseded by \ref arm_cfft_q15 and will be removed in the future.
46 @param[in,out] S points to an instance of the Q15 CFFT/CIFFT structure
47 @param[in] fftLen length of the FFT
48 @param[in] ifftFlag flag that selects transform direction
49 - value = 0: forward transform
50 - value = 1: inverse transform
51 @param[in] bitReverseFlag flag that enables / disables bit reversal of output
52 - value = 0: disables bit reversal of output
53 - value = 1: enables bit reversal of output
54 @return execution status
55 - \ref ARM_MATH_SUCCESS : Operation successful
56 - \ref ARM_MATH_ARGUMENT_ERROR : <code>fftLen</code> is not a supported length
57
58 @par Details
59 The parameter <code>ifftFlag</code> controls whether a forward or inverse transform is computed.
60 Set(=1) ifftFlag for calculation of CIFFT otherwise CFFT is calculated
61 @par
62 The parameter <code>bitReverseFlag</code> controls whether output is in normal order or bit reversed order.
63 Set(=1) bitReverseFlag for output to be in normal order otherwise output is in bit reversed order.
64 @par
65 The parameter <code>fftLen</code> Specifies length of CFFT/CIFFT process. Supported FFT Lengths are 16, 64, 256, 1024.
66 @par
67 This Function also initializes Twiddle factor table pointer and Bit reversal table pointer.
68 */
69
arm_cfft_radix4_init_q15(arm_cfft_radix4_instance_q15 * S,uint16_t fftLen,uint8_t ifftFlag,uint8_t bitReverseFlag)70 arm_status arm_cfft_radix4_init_q15(
71 arm_cfft_radix4_instance_q15 * S,
72 uint16_t fftLen,
73 uint8_t ifftFlag,
74 uint8_t bitReverseFlag)
75 {
76 /* Initialise the default arm status */
77 arm_status status = ARM_MATH_ARGUMENT_ERROR;
78
79 #if !defined(ARM_DSP_CONFIG_TABLES) || defined(ARM_FFT_ALLOW_TABLES)
80
81 #if !defined(ARM_DSP_CONFIG_TABLES) || defined(ARM_ALL_FFT_TABLES) || defined(ARM_TABLE_TWIDDLECOEF_Q15_4096)
82
83 /* Initialise the default arm status */
84 status = ARM_MATH_SUCCESS;
85 /* Initialise the FFT length */
86 S->fftLen = fftLen;
87 /* Initialise the Twiddle coefficient pointer */
88 S->pTwiddle = (q15_t *) twiddleCoef_4096_q15;
89 /* Initialise the Flag for selection of CFFT or CIFFT */
90 S->ifftFlag = ifftFlag;
91 /* Initialise the Flag for calculation Bit reversal or not */
92 S->bitReverseFlag = bitReverseFlag;
93
94 #if !defined(ARM_DSP_CONFIG_TABLES) || defined(ARM_ALL_FFT_TABLES) || defined(ARM_TABLE_BITREV_1024)
95
96 /* Initializations of structure parameters depending on the FFT length */
97 switch (S->fftLen)
98 {
99 case 4096U:
100 /* Initializations of structure parameters for 4096 point FFT */
101
102 /* Initialise the twiddle coef modifier value */
103 S->twidCoefModifier = 1U;
104 /* Initialise the bit reversal table modifier */
105 S->bitRevFactor = 1U;
106 /* Initialise the bit reversal table pointer */
107 S->pBitRevTable = (uint16_t *) armBitRevTable;
108
109 break;
110
111 case 1024U:
112 /* Initializations of structure parameters for 1024 point FFT */
113 S->twidCoefModifier = 4U;
114 S->bitRevFactor = 4U;
115 S->pBitRevTable = (uint16_t *) & armBitRevTable[3];
116
117 break;
118
119 case 256U:
120 /* Initializations of structure parameters for 256 point FFT */
121 S->twidCoefModifier = 16U;
122 S->bitRevFactor = 16U;
123 S->pBitRevTable = (uint16_t *) & armBitRevTable[15];
124
125 break;
126
127 case 64U:
128 /* Initializations of structure parameters for 64 point FFT */
129 S->twidCoefModifier = 64U;
130 S->bitRevFactor = 64U;
131 S->pBitRevTable = (uint16_t *) & armBitRevTable[63];
132
133 break;
134
135 case 16U:
136 /* Initializations of structure parameters for 16 point FFT */
137 S->twidCoefModifier = 256U;
138 S->bitRevFactor = 256U;
139 S->pBitRevTable = (uint16_t *) & armBitRevTable[255];
140
141 break;
142
143 default:
144 /* Reporting argument error if fftSize is not valid value */
145 status = ARM_MATH_ARGUMENT_ERROR;
146 break;
147 }
148
149 #endif
150 #endif
151 #endif
152 return (status);
153 }
154
155 /**
156 @} end of ComplexFFT group
157 */
158
