1 /* ----------------------------------------------------------------------
2 * Copyright (C) 2010-2013 ARM Limited. All rights reserved.
4 * $Date: 17. January 2013
7 * Project: CMSIS DSP Library
8 * Title: arm_cfft_radix4_init_f32.c
10 * Description: Radix-4 Decimation in Frequency Floating-point CFFT & CIFFT Initialization function
12 * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
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15 * modification, are permitted provided that the following conditions
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20 * notice, this list of conditions and the following disclaimer in
21 * the documentation and/or other materials provided with the
23 * - Neither the name of ARM LIMITED nor the names of its contributors
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25 * software without specific prior written permission.
27 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
28 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
29 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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39 * -------------------------------------------------------------------- */
43 #include "arm_common_tables.h"
46 * @ingroup groupTransforms
50 * @addtogroup ComplexFFT
55 * @brief Initialization function for the floating-point CFFT/CIFFT.
56 * @deprecated Do not use this function. It has been superceded by \ref arm_cfft_f32 and will be removed
58 * @param[in,out] *S points to an instance of the floating-point CFFT/CIFFT structure.
59 * @param[in] fftLen length of the FFT.
60 * @param[in] ifftFlag flag that selects forward (ifftFlag=0) or inverse (ifftFlag=1) transform.
61 * @param[in] bitReverseFlag flag that enables (bitReverseFlag=1) or disables (bitReverseFlag=0) bit reversal of output.
62 * @return The function returns ARM_MATH_SUCCESS if initialization is successful or ARM_MATH_ARGUMENT_ERROR if <code>fftLen</code> is not a supported value.
66 * The parameter <code>ifftFlag</code> controls whether a forward or inverse transform is computed.
67 * Set(=1) ifftFlag for calculation of CIFFT otherwise CFFT is calculated
69 * The parameter <code>bitReverseFlag</code> controls whether output is in normal order or bit reversed order.
70 * Set(=1) bitReverseFlag for output to be in normal order otherwise output is in bit reversed order.
72 * The parameter <code>fftLen</code> Specifies length of CFFT/CIFFT process. Supported FFT Lengths are 16, 64, 256, 1024.
74 * This Function also initializes Twiddle factor table pointer and Bit reversal table pointer.
77 arm_status
arm_cfft_radix4_init_f32(
78 arm_cfft_radix4_instance_f32
* S
,
81 uint8_t bitReverseFlag
)
83 /* Initialise the default arm status */
84 arm_status status
= ARM_MATH_SUCCESS
;
86 /* Initialise the FFT length */
89 /* Initialise the Twiddle coefficient pointer */
90 S
->pTwiddle
= (float32_t
*) twiddleCoef
;
92 /* Initialise the Flag for selection of CFFT or CIFFT */
93 S
->ifftFlag
= ifftFlag
;
95 /* Initialise the Flag for calculation Bit reversal or not */
96 S
->bitReverseFlag
= bitReverseFlag
;
98 /* Initializations of structure parameters depending on the FFT length */
103 /* Initializations of structure parameters for 4096 point FFT */
105 /* Initialise the twiddle coef modifier value */
106 S
->twidCoefModifier
= 1u;
107 /* Initialise the bit reversal table modifier */
108 S
->bitRevFactor
= 1u;
109 /* Initialise the bit reversal table pointer */
110 S
->pBitRevTable
= (uint16_t *) armBitRevTable
;
111 /* Initialise the 1/fftLen Value */
112 S
->onebyfftLen
= 0.000244140625;
116 /* Initializations of structure parameters for 1024 point FFT */
118 /* Initialise the twiddle coef modifier value */
119 S
->twidCoefModifier
= 4u;
120 /* Initialise the bit reversal table modifier */
121 S
->bitRevFactor
= 4u;
122 /* Initialise the bit reversal table pointer */
123 S
->pBitRevTable
= (uint16_t *) & armBitRevTable
[3];
124 /* Initialise the 1/fftLen Value */
125 S
->onebyfftLen
= 0.0009765625f
;
130 /* Initializations of structure parameters for 256 point FFT */
131 S
->twidCoefModifier
= 16u;
132 S
->bitRevFactor
= 16u;
133 S
->pBitRevTable
= (uint16_t *) & armBitRevTable
[15];
134 S
->onebyfftLen
= 0.00390625f
;
138 /* Initializations of structure parameters for 64 point FFT */
139 S
->twidCoefModifier
= 64u;
140 S
->bitRevFactor
= 64u;
141 S
->pBitRevTable
= (uint16_t *) & armBitRevTable
[63];
142 S
->onebyfftLen
= 0.015625f
;
146 /* Initializations of structure parameters for 16 point FFT */
147 S
->twidCoefModifier
= 256u;
148 S
->bitRevFactor
= 256u;
149 S
->pBitRevTable
= (uint16_t *) & armBitRevTable
[255];
150 S
->onebyfftLen
= 0.0625f
;
155 /* Reporting argument error if fftSize is not valid value */
156 status
= ARM_MATH_ARGUMENT_ERROR
;
164 * @} end of ComplexFFT group