1 /* ----------------------------------------------------------------------
2 * Project: CMSIS DSP Library
3 * Title: arm_cfft_radix4_init_q31.c
4 * Description: Radix-4 Decimation in Frequency Q31 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 @addtogroup ComplexFFTDeprecated
34 @{
35 */
36
37 /**
38
39 @brief Initialization function for the Q31 CFFT/CIFFT.
40 @deprecated Do not use this function. It has been superseded by \ref arm_cfft_q31 and will be removed in the future.
41 @param[in,out] S points to an instance of the Q31 CFFT/CIFFT structure.
42 @param[in] fftLen length of the FFT.
43 @param[in] ifftFlag flag that selects transform direction
44 - value = 0: forward transform
45 - value = 1: inverse transform
46 @param[in] bitReverseFlag flag that enables / disables bit reversal of output
47 - value = 0: disables bit reversal of output
48 - value = 1: enables bit reversal of output
49 @return execution status
50 - \ref ARM_MATH_SUCCESS : Operation successful
51 - \ref ARM_MATH_ARGUMENT_ERROR : <code>fftLen</code> is not a supported length
52
53 @par Details
54 The parameter <code>ifftFlag</code> controls whether a forward or inverse transform is computed.
55 Set(=1) ifftFlag for calculation of CIFFT otherwise CFFT is calculated
56 @par
57 The parameter <code>bitReverseFlag</code> controls whether output is in normal order or bit reversed order.
58 Set(=1) bitReverseFlag for output to be in normal order otherwise output is in bit reversed order.
59 @par
60 The parameter <code>fftLen</code> Specifies length of CFFT/CIFFT process. Supported FFT Lengths are 16, 64, 256, 1024.
61 @par
62 This Function also initializes Twiddle factor table pointer and Bit reversal table pointer.
63 */
64
arm_cfft_radix4_init_q31(arm_cfft_radix4_instance_q31 * S,uint16_t fftLen,uint8_t ifftFlag,uint8_t bitReverseFlag)65 arm_status arm_cfft_radix4_init_q31(
66 arm_cfft_radix4_instance_q31 * S,
67 uint16_t fftLen,
68 uint8_t ifftFlag,
69 uint8_t bitReverseFlag)
70 {
71
72 /* Initialise the default arm status */
73 arm_status status = ARM_MATH_ARGUMENT_ERROR;
74
75 /* Initialise the default arm status */
76 status = ARM_MATH_SUCCESS;
77 /* Initialise the FFT length */
78 S->fftLen = fftLen;
79 /* Initialise the Twiddle coefficient pointer */
80 S->pTwiddle = (q31_t *) twiddleCoef_4096_q31;
81 /* Initialise the Flag for selection of CFFT or CIFFT */
82 S->ifftFlag = ifftFlag;
83 /* Initialise the Flag for calculation Bit reversal or not */
84 S->bitReverseFlag = bitReverseFlag;
85
86 /* Initializations of Instance structure depending on the FFT length */
87 switch (S->fftLen)
88 {
89 /* Initializations of structure parameters for 4096 point FFT */
90 case 4096U:
91 /* Initialise the twiddle coef modifier value */
92 S->twidCoefModifier = 1U;
93 /* Initialise the bit reversal table modifier */
94 S->bitRevFactor = 1U;
95 /* Initialise the bit reversal table pointer */
96 S->pBitRevTable = (uint16_t *) armBitRevTable;
97 break;
98
99 /* Initializations of structure parameters for 1024 point FFT */
100 case 1024U:
101 /* Initialise the twiddle coef modifier value */
102 S->twidCoefModifier = 4U;
103 /* Initialise the bit reversal table modifier */
104 S->bitRevFactor = 4U;
105 /* Initialise the bit reversal table pointer */
106 S->pBitRevTable = (uint16_t *) & armBitRevTable[3];
107 break;
108
109 case 256U:
110 /* Initializations of structure parameters for 256 point FFT */
111 S->twidCoefModifier = 16U;
112 S->bitRevFactor = 16U;
113 S->pBitRevTable = (uint16_t *) & armBitRevTable[15];
114 break;
115
116 case 64U:
117 /* Initializations of structure parameters for 64 point FFT */
118 S->twidCoefModifier = 64U;
119 S->bitRevFactor = 64U;
120 S->pBitRevTable = (uint16_t *) & armBitRevTable[63];
121 break;
122
123 case 16U:
124 /* Initializations of structure parameters for 16 point FFT */
125 S->twidCoefModifier = 256U;
126 S->bitRevFactor = 256U;
127 S->pBitRevTable = (uint16_t *) & armBitRevTable[255];
128 break;
129
130 default:
131 /* Reporting argument error if fftSize is not valid value */
132 status = ARM_MATH_ARGUMENT_ERROR;
133 break;
134 }
135
136 return (status);
137 }
138
139 /**
140 @} end of ComplexFFTDeprecated group
141 */
142
