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+/* ----------------------------------------------------------------------
+ * 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 It has been superceded by \ref arm_rfft_fast_init_f32 and will be removed in the future.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
+ */