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/* ----------------------------------------------------------------------
* Copyright (C) 2010-2014 ARM Limited. All rights reserved.
*
* $Date: 31. July 2014
* $Revision: V1.4.4
*
* Project: CMSIS DSP Library
* Title: arm_cfft_init_f32.c
*
* Description: Split Radix Decimation in Frequency CFFT Floating point processing function
*
* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* - Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* - Neither the name of ARM LIMITED nor the names of its contributors
* may be used to endorse or promote products derived from this
* software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
* -------------------------------------------------------------------- */
#include "arm_math.h"
#include "arm_common_tables.h"
/**
* @ingroup groupTransforms
*/
/**
* @addtogroup RealFFT
* @{
*/
/**
* @brief Initialization function for the floating-point real FFT.
* @param[in,out] *S points to an arm_rfft_fast_instance_f32 structure.
* @param[in] fftLen length of the Real Sequence.
* @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.
*
* \par Description:
* \par
* The parameter <code>ifftFlag</code> controls whether a forward or inverse transform is computed.
* Set(=1) ifftFlag for calculation of CIFFT 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
* The parameter <code>fftLen</code> Specifies length of RFFT/CIFFT process. Supported FFT Lengths are 16, 32, 64, 128, 256, 512, 1024, 2048, 4096.
* \par
* This Function also initializes Twiddle factor table pointer and Bit reversal table pointer.
*/
arm_status arm_rfft_fast_init_f32(
arm_rfft_fast_instance_f32 * S,
uint16_t fftLen)
{
arm_cfft_instance_f32 * Sint;
/* Initialise the default arm status */
arm_status status = ARM_MATH_SUCCESS;
/* Initialise the FFT length */
Sint = &(S->Sint);
Sint->fftLen = fftLen/2;
S->fftLenRFFT = fftLen;
/* Initializations of structure parameters depending on the FFT length */
switch (Sint->fftLen)
{
case 2048u:
/* Initializations of structure parameters for 2048 point FFT */
/* Initialise the bit reversal table length */
Sint->bitRevLength = ARMBITREVINDEXTABLE2048_TABLE_LENGTH;
/* Initialise the bit reversal table pointer */
Sint->pBitRevTable = (uint16_t *)armBitRevIndexTable2048;
/* Initialise the Twiddle coefficient pointers */
Sint->pTwiddle = (float32_t *) twiddleCoef_2048;
S->pTwiddleRFFT = (float32_t *) twiddleCoef_rfft_4096;
break;
case 1024u:
Sint->bitRevLength = ARMBITREVINDEXTABLE1024_TABLE_LENGTH;
Sint->pBitRevTable = (uint16_t *)armBitRevIndexTable1024;
Sint->pTwiddle = (float32_t *) twiddleCoef_1024;
S->pTwiddleRFFT = (float32_t *) twiddleCoef_rfft_2048;
break;
case 512u:
Sint->bitRevLength = ARMBITREVINDEXTABLE_512_TABLE_LENGTH;
Sint->pBitRevTable = (uint16_t *)armBitRevIndexTable512;
Sint->pTwiddle = (float32_t *) twiddleCoef_512;
S->pTwiddleRFFT = (float32_t *) twiddleCoef_rfft_1024;
break;
case 256u:
Sint->bitRevLength = ARMBITREVINDEXTABLE_256_TABLE_LENGTH;
Sint->pBitRevTable = (uint16_t *)armBitRevIndexTable256;
Sint->pTwiddle = (float32_t *) twiddleCoef_256;
S->pTwiddleRFFT = (float32_t *) twiddleCoef_rfft_512;
break;
case 128u:
Sint->bitRevLength = ARMBITREVINDEXTABLE_128_TABLE_LENGTH;
Sint->pBitRevTable = (uint16_t *)armBitRevIndexTable128;
Sint->pTwiddle = (float32_t *) twiddleCoef_128;
S->pTwiddleRFFT = (float32_t *) twiddleCoef_rfft_256;
break;
case 64u:
Sint->bitRevLength = ARMBITREVINDEXTABLE__64_TABLE_LENGTH;
Sint->pBitRevTable = (uint16_t *)armBitRevIndexTable64;
Sint->pTwiddle = (float32_t *) twiddleCoef_64;
S->pTwiddleRFFT = (float32_t *) twiddleCoef_rfft_128;
break;
case 32u:
Sint->bitRevLength = ARMBITREVINDEXTABLE__32_TABLE_LENGTH;
Sint->pBitRevTable = (uint16_t *)armBitRevIndexTable32;
Sint->pTwiddle = (float32_t *) twiddleCoef_32;
S->pTwiddleRFFT = (float32_t *) twiddleCoef_rfft_64;
break;
case 16u:
Sint->bitRevLength = ARMBITREVINDEXTABLE__16_TABLE_LENGTH;
Sint->pBitRevTable = (uint16_t *)armBitRevIndexTable16;
Sint->pTwiddle = (float32_t *) twiddleCoef_16;
S->pTwiddleRFFT = (float32_t *) twiddleCoef_rfft_32;
break;
default:
/* Reporting argument error if fftSize is not valid value */
status = ARM_MATH_ARGUMENT_ERROR;
break;
}
return (status);
}
/**
* @} end of RealFFT group
*/
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