| /* ---------------------------------------------------------------------- |
| * 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 "arm_math.h" |
| #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 It has been superceded by \ref arm_rfft_fast_init_f32 and will be removed in the future.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_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); |
| } |
| |
| /* return the status of RFFT Init function */ |
| return (status); |
| |
| } |
| |
| /** |
| @} end of RealFFT group |
| */ |