1  /* ----------------------------------------------------------------------
  2   * Project:      CMSIS DSP Library
  3   * Title:        arm_rfft_init_f32.c
  4   * Description:  RFFT & RIFFT Floating point initialisation 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  /**
 34    @addtogroup RealFFT
 35    @{
 36   */
 37  
 38  /**
 39    @brief         Initialization function for the floating-point RFFT/RIFFT.
 40    @deprecated    Do not use this function. It has been superceded by \ref arm_rfft_fast_init_f32 and will be removed in the future.
 41    @param[in,out] S             points to an instance of the floating-point RFFT/RIFFT structure
 42    @param[in,out] S_CFFT        points to an instance of the floating-point CFFT/CIFFT structure
 43    @param[in]     fftLenReal     length of the FFT.
 44    @param[in]     ifftFlagR      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>fftLenReal</code> is not a supported length
 53  
 54    @par Description
 55                     The parameter <code>fftLenReal</code>specifies length of RFFT/RIFFT Process.
 56                     Supported FFT Lengths are 128, 512, 2048.
 57    @par
 58                     The parameter <code>ifftFlagR</code> controls whether a forward or inverse transform is computed.
 59                     Set(=1) ifftFlagR to calculate RIFFT, otherwise RFFT is calculated.
 60    @par
 61                     The parameter <code>bitReverseFlag</code> controls whether output is in normal order or bit reversed order.
 62                     Set(=1) bitReverseFlag for output to be in normal order otherwise output is in bit reversed order.
 63    @par
 64                     This function also initializes Twiddle factor table.
 65   */
 66  
 67  arm_status arm_rfft_init_f32(
 68    arm_rfft_instance_f32 * S,
 69    arm_cfft_radix4_instance_f32 * S_CFFT,
 70    uint32_t fftLenReal,
 71    uint32_t ifftFlagR,
 72    uint32_t bitReverseFlag)
 73  {
 74     /*  Initialise the default arm status */
 75    arm_status status = ARM_MATH_ARGUMENT_ERROR;
 76  
 77  #if !defined(ARM_DSP_CONFIG_TABLES) || defined(ARM_FFT_ALLOW_TABLES)
 78  
 79  #if !defined(ARM_DSP_CONFIG_TABLES) || defined(ARM_ALL_FFT_TABLES) || defined(ARM_TABLE_REALCOEF_F32)
 80  
 81    /*  Initialise the default arm status */
 82    status = ARM_MATH_SUCCESS;
 83  
 84    /*  Initialize the Real FFT length */
 85    S->fftLenReal = (uint16_t) fftLenReal;
 86  
 87    /*  Initialize the Complex FFT length */
 88    S->fftLenBy2 = (uint16_t) fftLenReal / 2U;
 89  
 90    /*  Initialize the Twiddle coefficientA pointer */
 91    S->pTwiddleAReal = (float32_t *) realCoefA;
 92  
 93    /*  Initialize the Twiddle coefficientB pointer */
 94    S->pTwiddleBReal = (float32_t *) realCoefB;
 95  
 96    /*  Initialize the Flag for selection of RFFT or RIFFT */
 97    S->ifftFlagR = (uint8_t) ifftFlagR;
 98  
 99    /*  Initialize the Flag for calculation Bit reversal or not */
100    S->bitReverseFlagR = (uint8_t) bitReverseFlag;
101  
102    /*  Initializations of structure parameters depending on the FFT length */
103    switch (S->fftLenReal)
104    {
105      /* Init table modifier value */
106    case 8192U:
107      S->twidCoefRModifier = 1U;
108      break;
109    case 2048U:
110      S->twidCoefRModifier = 4U;
111      break;
112    case 512U:
113      S->twidCoefRModifier = 16U;
114      break;
115    case 128U:
116      S->twidCoefRModifier = 64U;
117      break;
118    default:
119      /*  Reporting argument error if rfftSize is not valid value */
120      status = ARM_MATH_ARGUMENT_ERROR;
121      break;
122    }
123  
124    /* Init Complex FFT Instance */
125    S->pCfft = S_CFFT;
126  
127    if (S->ifftFlagR)
128    {
129      /* Initializes the CIFFT Module for fftLenreal/2 length */
130      arm_cfft_radix4_init_f32(S->pCfft, S->fftLenBy2, 1U, 0U);
131    }
132    else
133    {
134      /* Initializes the CFFT Module for fftLenreal/2 length */
135      arm_cfft_radix4_init_f32(S->pCfft, S->fftLenBy2, 0U, 0U);
136    }
137  
138  #endif
139  #endif
140    /* return the status of RFFT Init function */
141    return (status);
142  
143  }
144  
145  /**
146    @} end of RealFFT group
147   */