text: #include "edge-impulse-sdk/dsp/config.hpp"
  #if EIDSP_LOAD_CMSIS_DSP_SOURCES
  /* ----------------------------------------------------------------------
   * Project:      CMSIS DSP Library
   * Title:        arm_rfft_init_f32.c
   * Description:  RFFT & RIFFT Floating point initialisation function
   *
   * $Date:        18. March 2019
   * $Revision:    V1.6.0
   *
   * Target Processor: Cortex-M cores
   * -------------------------------------------------------------------- */
  /*
   * Copyright (C) 2010-2019 ARM Limited or its affiliates. All rights reserved.
   *
   * SPDX-License-Identifier: Apache-2.0
   *
   * Licensed under the Apache License, Version 2.0 (the License); you may
   * not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   * www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an AS IS BASIS, WITHOUT
   * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  #include "edge-impulse-sdk/CMSIS/DSP/Include/dsp/transform_functions.h"
  #include "edge-impulse-sdk/CMSIS/DSP/Include/arm_common_tables.h"
  
  
  /**
    @addtogroup RealFFT
    @{
   */
  
  /**
    @brief         Initialization function for the floating-point RFFT/RIFFT.
    @deprecated    Do not use this function. It has been superceded by \ref arm_rfft_fast_init_f32 and will be removed in the future.
    @param[in,out] S             points to an instance of the floating-point RFFT/RIFFT structure
    @param[in,out] S_CFFT        points to an instance of the floating-point CFFT/CIFFT structure
    @param[in]     fftLenReal     length of the FFT.
    @param[in]     ifftFlagR      flag that selects transform direction
                     - value = 0: forward transform
                     - value = 1: inverse transform
    @param[in]     bitReverseFlag flag that enables / disables bit reversal of output
                     - value = 0: disables bit reversal of output
                     - value = 1: enables bit reversal of output
    @return        execution status
                     - \ref ARM_MATH_SUCCESS        : Operation successful
                     - \ref ARM_MATH_ARGUMENT_ERROR : <code>fftLenReal</code> is not a supported length
  
    @par Description
                     The parameter <code>fftLenReal</code>specifies length of RFFT/RIFFT Process.
                     Supported FFT Lengths are 128, 512, 2048.
    @par
                     The parameter <code>ifftFlagR</code> controls whether a forward or inverse transform is computed.
                     Set(=1) ifftFlagR to calculate RIFFT, otherwise RFFT is calculated.
    @par
                     The parameter <code>bitReverseFlag</code> controls whether output is in normal order or bit reversed order.
                     Set(=1) bitReverseFlag for output to be in normal order otherwise output is in bit reversed order.
    @par
                     This function also initializes Twiddle factor table.
   */
  
  arm_status arm_rfft_init_f32(
    arm_rfft_instance_f32 * S,
    arm_cfft_radix4_instance_f32 * S_CFFT,
    uint32_t fftLenReal,
    uint32_t ifftFlagR,
    uint32_t bitReverseFlag)
  {
     /*  Initialise the default arm status */
    arm_status status = ARM_MATH_ARGUMENT_ERROR;
  
  #if !defined(ARM_DSP_CONFIG_TABLES) || defined(ARM_FFT_ALLOW_TABLES)
  
  #if !defined(ARM_DSP_CONFIG_TABLES) || defined(ARM_ALL_FFT_TABLES) || defined(ARM_TABLE_REALCOEF_F32)
  
    /*  Initialise the default arm status */
    status = ARM_MATH_SUCCESS;
  
    /*  Initialize the Real FFT length */
    S->fftLenReal = (uint16_t) fftLenReal;
  
    /*  Initialize the Complex FFT length */
    S->fftLenBy2 = (uint16_t) fftLenReal / 2U;
  
    /*  Initialize the Twiddle coefficientA pointer */
    S->pTwiddleAReal = (float32_t *) realCoefA;
  
    /*  Initialize the Twiddle coefficientB pointer */
    S->pTwiddleBReal = (float32_t *) realCoefB;
  
    /*  Initialize the Flag for selection of RFFT or RIFFT */
    S->ifftFlagR = (uint8_t) ifftFlagR;
  
    /*  Initialize the Flag for calculation Bit reversal or not */
    S->bitReverseFlagR = (uint8_t) bitReverseFlag;
  
    /*  Initializations of structure parameters depending on the FFT length */
    switch (S->fftLenReal)
    {
      /* Init table modifier value */
    case 8192U:
      S->twidCoefRModifier = 1U;
      break;
    case 2048U:
      S->twidCoefRModifier = 4U;
      break;
    case 512U:
      S->twidCoefRModifier = 16U;
      break;
    case 128U:
      S->twidCoefRModifier = 64U;
      break;
    default:
      /*  Reporting argument error if rfftSize is not valid value */
      status = ARM_MATH_ARGUMENT_ERROR;
      break;
    }
  
    /* Init Complex FFT Instance */
    S->pCfft = S_CFFT;
  
    if (S->ifftFlagR)
    {
      /* Initializes the CIFFT Module for fftLenreal/2 length */
      arm_cfft_radix4_init_f32(S->pCfft, S->fftLenBy2, 1U, 0U);
    }
    else
    {
      /* Initializes the CFFT Module for fftLenreal/2 length */
      arm_cfft_radix4_init_f32(S->pCfft, S->fftLenBy2, 0U, 0U);
    }
  
  #endif
  #endif
    /* return the status of RFFT Init function */
    return (status);
  
  }
  
  /**
    @} end of RealFFT group
   */
  
  #endif // EIDSP_LOAD_CMSIS_DSP_SOURCES
  