| /* ---------------------------------------------------------------------- |
| * Project: CMSIS DSP Library |
| * Title: arm_rfft_init_q31.c |
| * Description: RFFT & RIFFT Q31 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" |
| #include "arm_const_structs.h" |
| |
| |
| |
| /** |
| @addtogroup RealFFT |
| @{ |
| */ |
| |
| /** |
| @brief Initialization function for the Q31 RFFT/RIFFT. |
| @param[in,out] S points to an instance of the Q31 RFFT/RIFFT 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 Details |
| The parameter <code>fftLenReal</code> specifies length of RFFT/RIFFT Process. |
| Supported FFT Lengths are 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192. |
| @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_q31( |
| arm_rfft_instance_q31 * S, |
| 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 Twiddle coefficientA pointer */ |
| S->pTwiddleAReal = (q31_t *) realCoefAQ31; |
| |
| /* Initialize the Twiddle coefficientB pointer */ |
| S->pTwiddleBReal = (q31_t *) realCoefBQ31; |
| |
| /* 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; |
| |
| /* Initialization of coef modifier depending on the FFT length */ |
| switch (S->fftLenReal) |
| { |
| #if !defined(ARM_DSP_CONFIG_TABLES) || defined(ARM_ALL_FFT_TABLES) || (defined(ARM_TABLE_TWIDDLECOEF_Q31_4096) && defined(ARM_TABLE_BITREVIDX_FXT_4096)) |
| case 8192U: |
| S->twidCoefRModifier = 1U; |
| S->pCfft = &arm_cfft_sR_q31_len4096; |
| break; |
| #endif |
| #if !defined(ARM_DSP_CONFIG_TABLES) || defined(ARM_ALL_FFT_TABLES) || (defined(ARM_TABLE_TWIDDLECOEF_Q31_2048) && defined(ARM_TABLE_BITREVIDX_FXT_2048)) |
| case 4096U: |
| S->twidCoefRModifier = 2U; |
| S->pCfft = &arm_cfft_sR_q31_len2048; |
| break; |
| #endif |
| #if !defined(ARM_DSP_CONFIG_TABLES) || defined(ARM_ALL_FFT_TABLES) || (defined(ARM_TABLE_TWIDDLECOEF_Q31_1024) && defined(ARM_TABLE_BITREVIDX_FXT_1024)) |
| case 2048U: |
| S->twidCoefRModifier = 4U; |
| S->pCfft = &arm_cfft_sR_q31_len1024; |
| break; |
| #endif |
| #if !defined(ARM_DSP_CONFIG_TABLES) || defined(ARM_ALL_FFT_TABLES) || (defined(ARM_TABLE_TWIDDLECOEF_Q31_512) && defined(ARM_TABLE_BITREVIDX_FXT_512)) |
| case 1024U: |
| S->twidCoefRModifier = 8U; |
| S->pCfft = &arm_cfft_sR_q31_len512; |
| break; |
| #endif |
| #if !defined(ARM_DSP_CONFIG_TABLES) || defined(ARM_ALL_FFT_TABLES) || (defined(ARM_TABLE_TWIDDLECOEF_Q31_256) && defined(ARM_TABLE_BITREVIDX_FXT_256)) |
| case 512U: |
| S->twidCoefRModifier = 16U; |
| S->pCfft = &arm_cfft_sR_q31_len256; |
| break; |
| #endif |
| #if !defined(ARM_DSP_CONFIG_TABLES) || defined(ARM_ALL_FFT_TABLES) || (defined(ARM_TABLE_TWIDDLECOEF_Q31_128) && defined(ARM_TABLE_BITREVIDX_FXT_128)) |
| case 256U: |
| S->twidCoefRModifier = 32U; |
| S->pCfft = &arm_cfft_sR_q31_len128; |
| break; |
| #endif |
| #if !defined(ARM_DSP_CONFIG_TABLES) || defined(ARM_ALL_FFT_TABLES) || (defined(ARM_TABLE_TWIDDLECOEF_Q31_64) && defined(ARM_TABLE_BITREVIDX_FXT_64)) |
| case 128U: |
| S->twidCoefRModifier = 64U; |
| S->pCfft = &arm_cfft_sR_q31_len64; |
| break; |
| #endif |
| #if !defined(ARM_DSP_CONFIG_TABLES) || defined(ARM_ALL_FFT_TABLES) || (defined(ARM_TABLE_TWIDDLECOEF_Q31_32) && defined(ARM_TABLE_BITREVIDX_FXT_32)) |
| case 64U: |
| S->twidCoefRModifier = 128U; |
| S->pCfft = &arm_cfft_sR_q31_len32; |
| break; |
| #endif |
| #if !defined(ARM_DSP_CONFIG_TABLES) || defined(ARM_ALL_FFT_TABLES) || (defined(ARM_TABLE_TWIDDLECOEF_Q31_16) && defined(ARM_TABLE_BITREVIDX_FXT_16)) |
| case 32U: |
| S->twidCoefRModifier = 256U; |
| S->pCfft = &arm_cfft_sR_q31_len16; |
| break; |
| #endif |
| default: |
| /* Reporting argument error if rfftSize is not valid value */ |
| status = ARM_MATH_ARGUMENT_ERROR; |
| break; |
| } |
| |
| /* return the status of RFFT Init function */ |
| return (status); |
| } |
| |
| /** |
| @} end of RealFFT group |
| */ |