+++ /dev/null
-/* ----------------------------------------------------------------------
-* Copyright (C) 2010-2013 ARM Limited. All rights reserved.
-*
-* $Date: 17. January 2013
-* $Revision: V1.4.1
-*
-* Project: CMSIS DSP Library
-* Title: arm_rfft_q31.c
-*
-* Description: RFFT & RIFFT Q31 process 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"
-
-void arm_radix4_butterfly_inverse_q31(
-q31_t * pSrc,
-uint32_t fftLen,
-q31_t * pCoef,
-uint32_t twidCoefModifier);
-
-void arm_radix4_butterfly_q31(
-q31_t * pSrc,
-uint32_t fftLen,
-q31_t * pCoef,
-uint32_t twidCoefModifier);
-
-void arm_bitreversal_q31(
-q31_t * pSrc,
-uint32_t fftLen,
-uint16_t bitRevFactor,
-uint16_t * pBitRevTab);
-
-/*--------------------------------------------------------------------
-* Internal functions prototypes
---------------------------------------------------------------------*/
-
-void arm_split_rfft_q31(
- q31_t * pSrc,
- uint32_t fftLen,
- q31_t * pATable,
- q31_t * pBTable,
- q31_t * pDst,
- uint32_t modifier);
-
-void arm_split_rifft_q31(
- q31_t * pSrc,
- uint32_t fftLen,
- q31_t * pATable,
- q31_t * pBTable,
- q31_t * pDst,
- uint32_t modifier);
-
-/**
- * @addtogroup RealFFT
- * @{
- */
-
-/**
- * @brief Processing function for the Q31 RFFT/RIFFT.
- * @param[in] *S points to an instance of the Q31 RFFT/RIFFT structure.
- * @param[in] *pSrc points to the input buffer.
- * @param[out] *pDst points to the output buffer.
- * @return none.
- *
- * \par Input an output formats:
- * \par
- * Internally input is downscaled by 2 for every stage to avoid saturations inside CFFT/CIFFT process.
- * Hence the output format is different for different RFFT sizes.
- * The input and output formats for different RFFT sizes and number of bits to upscale are mentioned in the tables below for RFFT and RIFFT:
- * \par
- * \image html RFFTQ31.gif "Input and Output Formats for Q31 RFFT"
- *
- * \par
- * \image html RIFFTQ31.gif "Input and Output Formats for Q31 RIFFT"
- */
-
-void arm_rfft_q31(
- const arm_rfft_instance_q31 * S,
- q31_t * pSrc,
- q31_t * pDst)
-{
- const arm_cfft_radix4_instance_q31 *S_CFFT = S->pCfft;
-
- /* Calculation of RIFFT of input */
- if(S->ifftFlagR == 1u)
- {
- /* Real IFFT core process */
- arm_split_rifft_q31(pSrc, S->fftLenBy2, S->pTwiddleAReal,
- S->pTwiddleBReal, pDst, S->twidCoefRModifier);
-
- /* Complex readix-4 IFFT process */
- arm_radix4_butterfly_inverse_q31(pDst, S_CFFT->fftLen,
- S_CFFT->pTwiddle,
- S_CFFT->twidCoefModifier);
- /* Bit reversal process */
- if(S->bitReverseFlagR == 1u)
- {
- arm_bitreversal_q31(pDst, S_CFFT->fftLen,
- S_CFFT->bitRevFactor, S_CFFT->pBitRevTable);
- }
- }
- else
- {
- /* Calculation of RFFT of input */
-
- /* Complex readix-4 FFT process */
- arm_radix4_butterfly_q31(pSrc, S_CFFT->fftLen,
- S_CFFT->pTwiddle, S_CFFT->twidCoefModifier);
-
- /* Bit reversal process */
- if(S->bitReverseFlagR == 1u)
- {
- arm_bitreversal_q31(pSrc, S_CFFT->fftLen,
- S_CFFT->bitRevFactor, S_CFFT->pBitRevTable);
- }
-
- /* Real FFT core process */
- arm_split_rfft_q31(pSrc, S->fftLenBy2, S->pTwiddleAReal,
- S->pTwiddleBReal, pDst, S->twidCoefRModifier);
- }
-
-}
-
-
- /**
- * @} end of RealFFT group
- */
-
-/**
- * @brief Core Real FFT process
- * @param[in] *pSrc points to the input buffer.
- * @param[in] fftLen length of FFT.
- * @param[in] *pATable points to the twiddle Coef A buffer.
- * @param[in] *pBTable points to the twiddle Coef B buffer.
- * @param[out] *pDst points to the output buffer.
- * @param[in] modifier twiddle coefficient modifier that supports different size FFTs with the same twiddle factor table.
- * @return none.
- */
-
-void arm_split_rfft_q31(
- q31_t * pSrc,
- uint32_t fftLen,
- q31_t * pATable,
- q31_t * pBTable,
- q31_t * pDst,
- uint32_t modifier)
-{
- uint32_t i; /* Loop Counter */
- q31_t outR, outI; /* Temporary variables for output */
- q31_t *pCoefA, *pCoefB; /* Temporary pointers for twiddle factors */
- q31_t CoefA1, CoefA2, CoefB1; /* Temporary variables for twiddle coefficients */
- q31_t *pOut1 = &pDst[2], *pOut2 = &pDst[(4u * fftLen) - 1u];
- q31_t *pIn1 = &pSrc[2], *pIn2 = &pSrc[(2u * fftLen) - 1u];
-
- /* Init coefficient pointers */
- pCoefA = &pATable[modifier * 2u];
- pCoefB = &pBTable[modifier * 2u];
-
- i = fftLen - 1u;
-
- while(i > 0u)
- {
- /*
- outR = (pSrc[2 * i] * pATable[2 * i] - pSrc[2 * i + 1] * pATable[2 * i + 1]
- + pSrc[2 * n - 2 * i] * pBTable[2 * i] +
- pSrc[2 * n - 2 * i + 1] * pBTable[2 * i + 1]);
- */
-
- /* outI = (pIn[2 * i + 1] * pATable[2 * i] + pIn[2 * i] * pATable[2 * i + 1] +
- pIn[2 * n - 2 * i] * pBTable[2 * i + 1] -
- pIn[2 * n - 2 * i + 1] * pBTable[2 * i]); */
-
- CoefA1 = *pCoefA++;
- CoefA2 = *pCoefA;
-
- /* outR = (pSrc[2 * i] * pATable[2 * i] */
- outR = ((int32_t) (((q63_t) * pIn1 * CoefA1) >> 32));
-
- /* outI = pIn[2 * i] * pATable[2 * i + 1] */
- outI = ((int32_t) (((q63_t) * pIn1++ * CoefA2) >> 32));
-
- /* - pSrc[2 * i + 1] * pATable[2 * i + 1] */
- outR =
- (q31_t) ((((q63_t) outR << 32) + ((q63_t) * pIn1 * (-CoefA2))) >> 32);
-
- /* (pIn[2 * i + 1] * pATable[2 * i] */
- outI =
- (q31_t) ((((q63_t) outI << 32) + ((q63_t) * pIn1++ * (CoefA1))) >> 32);
-
- /* pSrc[2 * n - 2 * i] * pBTable[2 * i] */
- outR =
- (q31_t) ((((q63_t) outR << 32) + ((q63_t) * pIn2 * (-CoefA2))) >> 32);
- CoefB1 = *pCoefB;
-
- /* pIn[2 * n - 2 * i] * pBTable[2 * i + 1] */
- outI =
- (q31_t) ((((q63_t) outI << 32) + ((q63_t) * pIn2-- * (-CoefB1))) >> 32);
-
- /* pSrc[2 * n - 2 * i + 1] * pBTable[2 * i + 1] */
- outR =
- (q31_t) ((((q63_t) outR << 32) + ((q63_t) * pIn2 * (CoefB1))) >> 32);
-
- /* pIn[2 * n - 2 * i + 1] * pBTable[2 * i] */
- outI =
- (q31_t) ((((q63_t) outI << 32) + ((q63_t) * pIn2-- * (-CoefA2))) >> 32);
-
- /* write output */
- *pOut1++ = (outR << 1u);
- *pOut1++ = (outI << 1u);
-
- /* write complex conjugate output */
- *pOut2-- = -(outI << 1u);
- *pOut2-- = (outR << 1u);
-
- /* update coefficient pointer */
- pCoefB = pCoefB + (modifier * 2u);
- pCoefA = pCoefA + ((modifier * 2u) - 1u);
-
- i--;
-
- }
-
- pDst[2u * fftLen] = pSrc[0] - pSrc[1];
- pDst[(2u * fftLen) + 1u] = 0;
-
- pDst[0] = pSrc[0] + pSrc[1];
- pDst[1] = 0;
-
-}
-
-
-/**
- * @brief Core Real IFFT process
- * @param[in] *pSrc points to the input buffer.
- * @param[in] fftLen length of FFT.
- * @param[in] *pATable points to the twiddle Coef A buffer.
- * @param[in] *pBTable points to the twiddle Coef B buffer.
- * @param[out] *pDst points to the output buffer.
- * @param[in] modifier twiddle coefficient modifier that supports different size FFTs with the same twiddle factor table.
- * @return none.
- */
-
-void arm_split_rifft_q31(
- q31_t * pSrc,
- uint32_t fftLen,
- q31_t * pATable,
- q31_t * pBTable,
- q31_t * pDst,
- uint32_t modifier)
-{
- q31_t outR, outI; /* Temporary variables for output */
- q31_t *pCoefA, *pCoefB; /* Temporary pointers for twiddle factors */
- q31_t CoefA1, CoefA2, CoefB1; /* Temporary variables for twiddle coefficients */
- q31_t *pIn1 = &pSrc[0], *pIn2 = &pSrc[(2u * fftLen) + 1u];
-
- pCoefA = &pATable[0];
- pCoefB = &pBTable[0];
-
- while(fftLen > 0u)
- {
- /*
- outR = (pIn[2 * i] * pATable[2 * i] + pIn[2 * i + 1] * pATable[2 * i + 1] +
- pIn[2 * n - 2 * i] * pBTable[2 * i] -
- pIn[2 * n - 2 * i + 1] * pBTable[2 * i + 1]);
-
- outI = (pIn[2 * i + 1] * pATable[2 * i] - pIn[2 * i] * pATable[2 * i + 1] -
- pIn[2 * n - 2 * i] * pBTable[2 * i + 1] -
- pIn[2 * n - 2 * i + 1] * pBTable[2 * i]);
-
- */
- CoefA1 = *pCoefA++;
- CoefA2 = *pCoefA;
-
- /* outR = (pIn[2 * i] * pATable[2 * i] */
- outR = ((int32_t) (((q63_t) * pIn1 * CoefA1) >> 32));
-
- /* - pIn[2 * i] * pATable[2 * i + 1] */
- outI = -((int32_t) (((q63_t) * pIn1++ * CoefA2) >> 32));
-
- /* pIn[2 * i + 1] * pATable[2 * i + 1] */
- outR =
- (q31_t) ((((q63_t) outR << 32) + ((q63_t) * pIn1 * (CoefA2))) >> 32);
-
- /* pIn[2 * i + 1] * pATable[2 * i] */
- outI =
- (q31_t) ((((q63_t) outI << 32) + ((q63_t) * pIn1++ * (CoefA1))) >> 32);
-
- /* pIn[2 * n - 2 * i] * pBTable[2 * i] */
- outR =
- (q31_t) ((((q63_t) outR << 32) + ((q63_t) * pIn2 * (CoefA2))) >> 32);
-
- CoefB1 = *pCoefB;
-
- /* pIn[2 * n - 2 * i] * pBTable[2 * i + 1] */
- outI =
- (q31_t) ((((q63_t) outI << 32) - ((q63_t) * pIn2-- * (CoefB1))) >> 32);
-
- /* pIn[2 * n - 2 * i + 1] * pBTable[2 * i + 1] */
- outR =
- (q31_t) ((((q63_t) outR << 32) + ((q63_t) * pIn2 * (CoefB1))) >> 32);
-
- /* pIn[2 * n - 2 * i + 1] * pBTable[2 * i] */
- outI =
- (q31_t) ((((q63_t) outI << 32) + ((q63_t) * pIn2-- * (CoefA2))) >> 32);
-
- /* write output */
- *pDst++ = (outR << 1u);
- *pDst++ = (outI << 1u);
-
- /* update coefficient pointer */
- pCoefB = pCoefB + (modifier * 2u);
- pCoefA = pCoefA + ((modifier * 2u) - 1u);
-
- /* Decrement loop count */
- fftLen--;
-
- }
-
-
-}
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