/* ----------------------------------------------------------------------
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* Copyright (C) 2010-2014 ARM Limited. All rights reserved.
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*
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* $Date: 19. March 2015
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* $Revision: V.1.4.5
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*
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* Project: CMSIS DSP Library
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* Title: arm_cfft_init_f32.c
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*
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* Description: Split Radix Decimation in Frequency CFFT Floating point processing function
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*
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* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* - Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* - Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* - Neither the name of ARM LIMITED nor the names of its contributors
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* may be used to endorse or promote products derived from this
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* software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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* -------------------------------------------------------------------- */
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#include "arm_math.h"
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#include "arm_common_tables.h"
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/**
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* @ingroup groupTransforms
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*/
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/**
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* @addtogroup RealFFT
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* @{
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*/
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/**
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* @brief Initialization function for the floating-point real FFT.
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* @param[in,out] *S points to an arm_rfft_fast_instance_f32 structure.
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* @param[in] fftLen length of the Real Sequence.
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* @return The function returns ARM_MATH_SUCCESS if initialization is successful or ARM_MATH_ARGUMENT_ERROR if <code>fftLen</code> is not a supported value.
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*
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* \par Description:
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* \par
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* The parameter <code>fftLen</code> Specifies length of RFFT/CIFFT process. Supported FFT Lengths are 32, 64, 128, 256, 512, 1024, 2048, 4096.
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* \par
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* This Function also initializes Twiddle factor table pointer and Bit reversal table pointer.
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*/
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arm_status arm_rfft_fast_init_f32(
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arm_rfft_fast_instance_f32 * S,
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uint16_t fftLen)
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{
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arm_cfft_instance_f32 * Sint;
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/* Initialise the default arm status */
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arm_status status = ARM_MATH_SUCCESS;
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/* Initialise the FFT length */
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Sint = &(S->Sint);
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Sint->fftLen = fftLen/2;
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S->fftLenRFFT = fftLen;
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/* Initializations of structure parameters depending on the FFT length */
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switch (Sint->fftLen)
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{
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case 2048u:
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/* Initializations of structure parameters for 2048 point FFT */
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/* Initialise the bit reversal table length */
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Sint->bitRevLength = ARMBITREVINDEXTABLE2048_TABLE_LENGTH;
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/* Initialise the bit reversal table pointer */
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Sint->pBitRevTable = (uint16_t *)armBitRevIndexTable2048;
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/* Initialise the Twiddle coefficient pointers */
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Sint->pTwiddle = (float32_t *) twiddleCoef_2048;
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S->pTwiddleRFFT = (float32_t *) twiddleCoef_rfft_4096;
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break;
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case 1024u:
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Sint->bitRevLength = ARMBITREVINDEXTABLE1024_TABLE_LENGTH;
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Sint->pBitRevTable = (uint16_t *)armBitRevIndexTable1024;
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Sint->pTwiddle = (float32_t *) twiddleCoef_1024;
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S->pTwiddleRFFT = (float32_t *) twiddleCoef_rfft_2048;
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break;
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case 512u:
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Sint->bitRevLength = ARMBITREVINDEXTABLE_512_TABLE_LENGTH;
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Sint->pBitRevTable = (uint16_t *)armBitRevIndexTable512;
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Sint->pTwiddle = (float32_t *) twiddleCoef_512;
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S->pTwiddleRFFT = (float32_t *) twiddleCoef_rfft_1024;
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break;
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case 256u:
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Sint->bitRevLength = ARMBITREVINDEXTABLE_256_TABLE_LENGTH;
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Sint->pBitRevTable = (uint16_t *)armBitRevIndexTable256;
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Sint->pTwiddle = (float32_t *) twiddleCoef_256;
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S->pTwiddleRFFT = (float32_t *) twiddleCoef_rfft_512;
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break;
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case 128u:
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Sint->bitRevLength = ARMBITREVINDEXTABLE_128_TABLE_LENGTH;
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Sint->pBitRevTable = (uint16_t *)armBitRevIndexTable128;
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Sint->pTwiddle = (float32_t *) twiddleCoef_128;
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S->pTwiddleRFFT = (float32_t *) twiddleCoef_rfft_256;
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break;
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case 64u:
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Sint->bitRevLength = ARMBITREVINDEXTABLE__64_TABLE_LENGTH;
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Sint->pBitRevTable = (uint16_t *)armBitRevIndexTable64;
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Sint->pTwiddle = (float32_t *) twiddleCoef_64;
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S->pTwiddleRFFT = (float32_t *) twiddleCoef_rfft_128;
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break;
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case 32u:
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Sint->bitRevLength = ARMBITREVINDEXTABLE__32_TABLE_LENGTH;
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Sint->pBitRevTable = (uint16_t *)armBitRevIndexTable32;
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Sint->pTwiddle = (float32_t *) twiddleCoef_32;
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S->pTwiddleRFFT = (float32_t *) twiddleCoef_rfft_64;
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break;
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case 16u:
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Sint->bitRevLength = ARMBITREVINDEXTABLE__16_TABLE_LENGTH;
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Sint->pBitRevTable = (uint16_t *)armBitRevIndexTable16;
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Sint->pTwiddle = (float32_t *) twiddleCoef_16;
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S->pTwiddleRFFT = (float32_t *) twiddleCoef_rfft_32;
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break;
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default:
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/* Reporting argument error if fftSize is not valid value */
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status = ARM_MATH_ARGUMENT_ERROR;
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break;
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}
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return (status);
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}
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/**
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* @} end of RealFFT group
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*/
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