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/* ----------------------------------------------------------------------
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* Copyright (C) 2010 ARM Limited. All rights reserved.
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*
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* $Date: 15. July 2011
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* $Revision: V1.0.10
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*
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* Project: CMSIS DSP Library
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* Title: arm_rfft_q15.c
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*
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* Description: RFFT & RIFFT Q15 process function
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*
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*
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* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
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*
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* Version 1.0.10 2011/7/15
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* Big Endian support added and Merged M0 and M3/M4 Source code.
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*
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* Version 1.0.3 2010/11/29
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* Re-organized the CMSIS folders and updated documentation.
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*
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* Version 1.0.2 2010/11/11
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* Documentation updated.
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*
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* Version 1.0.1 2010/10/05
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* Production release and review comments incorporated.
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*
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* Version 1.0.0 2010/09/20
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* Production release and review comments incorporated
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*
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* Version 0.0.7 2010/06/10
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* Misra-C changes done
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* -------------------------------------------------------------------- */
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#include "arm_math.h"
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/*--------------------------------------------------------------------
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* Internal functions prototypes
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--------------------------------------------------------------------*/
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void arm_split_rfft_q15(
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q15_t * pSrc,
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uint32_t fftLen,
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q15_t * pATable,
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q15_t * pBTable,
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q15_t * pDst,
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uint32_t modifier);
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void arm_split_rifft_q15(
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q15_t * pSrc,
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uint32_t fftLen,
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q15_t * pATable,
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q15_t * pBTable,
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q15_t * pDst,
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uint32_t modifier);
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/**
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* @addtogroup RFFT_RIFFT
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* @{
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*/
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/**
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* @brief Processing function for the Q15 RFFT/RIFFT.
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* @param[in] *S points to an instance of the Q15 RFFT/RIFFT structure.
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* @param[in] *pSrc points to the input buffer.
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* @param[out] *pDst points to the output buffer.
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* @return none.
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*
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* \par Input an output formats:
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* \par
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* Internally input is downscaled by 2 for every stage to avoid saturations inside CFFT/CIFFT process.
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* Hence the output format is different for different RFFT sizes.
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* 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:
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* \par
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* \image html RFFTQ15.gif "Input and Output Formats for Q15 RFFT"
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* \par
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* \image html RIFFTQ15.gif "Input and Output Formats for Q15 RIFFT"
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*/
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void arm_rfft_q15(
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const arm_rfft_instance_q15 * S,
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q15_t * pSrc,
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q15_t * pDst)
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{
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const arm_cfft_radix4_instance_q15 *S_CFFT = S->pCfft;
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/* Calculation of RIFFT of input */
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if(S->ifftFlagR == 1u)
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{
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/* Real IFFT core process */
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arm_split_rifft_q15(pSrc, S->fftLenBy2, S->pTwiddleAReal,
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S->pTwiddleBReal, pDst, S->twidCoefRModifier);
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/* Complex readix-4 IFFT process */
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arm_radix4_butterfly_inverse_q15(pDst, S_CFFT->fftLen,
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S_CFFT->pTwiddle,
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S_CFFT->twidCoefModifier);
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/* Bit reversal process */
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if(S->bitReverseFlagR == 1u)
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{
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arm_bitreversal_q15(pDst, S_CFFT->fftLen,
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S_CFFT->bitRevFactor, S_CFFT->pBitRevTable);
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}
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}
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else
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{
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/* Calculation of RFFT of input */
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/* Complex readix-4 FFT process */
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arm_radix4_butterfly_q15(pSrc, S_CFFT->fftLen,
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S_CFFT->pTwiddle, S_CFFT->twidCoefModifier);
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/* Bit reversal process */
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if(S->bitReverseFlagR == 1u)
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{
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arm_bitreversal_q15(pSrc, S_CFFT->fftLen,
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S_CFFT->bitRevFactor, S_CFFT->pBitRevTable);
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}
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arm_split_rfft_q15(pSrc, S->fftLenBy2, S->pTwiddleAReal,
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S->pTwiddleBReal, pDst, S->twidCoefRModifier);
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}
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}
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/**
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* @} end of RFFT_RIFFT group
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*/
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/**
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* @brief Core Real FFT process
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* @param *pSrc points to the input buffer.
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* @param fftLen length of FFT.
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* @param *pATable points to the A twiddle Coef buffer.
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* @param *pBTable points to the B twiddle Coef buffer.
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* @param *pDst points to the output buffer.
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* @param modifier twiddle coefficient modifier that supports different size FFTs with the same twiddle factor table.
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* @return none.
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* The function implements a Real FFT
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*/
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void arm_split_rfft_q15(
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q15_t * pSrc,
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uint32_t fftLen,
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q15_t * pATable,
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q15_t * pBTable,
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q15_t * pDst,
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uint32_t modifier)
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{
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uint32_t i; /* Loop Counter */
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q31_t outR, outI; /* Temporary variables for output */
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q15_t *pCoefA, *pCoefB; /* Temporary pointers for twiddle factors */
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q15_t *pSrc1, *pSrc2;
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pSrc[2u * fftLen] = pSrc[0];
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pSrc[(2u * fftLen) + 1u] = pSrc[1];
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pCoefA = &pATable[modifier * 2u];
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pCoefB = &pBTable[modifier * 2u];
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pSrc1 = &pSrc[2];
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pSrc2 = &pSrc[(2u * fftLen) - 2u];
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#ifndef ARM_MATH_CM0
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/* Run the below code for Cortex-M4 and Cortex-M3 */
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i = 1u;
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while(i < fftLen)
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{
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/*
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outR = (pSrc[2 * i] * pATable[2 * i] - pSrc[2 * i + 1] * pATable[2 * i + 1]
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+ pSrc[2 * n - 2 * i] * pBTable[2 * i] +
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pSrc[2 * n - 2 * i + 1] * pBTable[2 * i + 1]);
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*/
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/* outI = (pIn[2 * i + 1] * pATable[2 * i] + pIn[2 * i] * pATable[2 * i + 1] +
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pIn[2 * n - 2 * i] * pBTable[2 * i + 1] -
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pIn[2 * n - 2 * i + 1] * pBTable[2 * i]); */
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#ifndef ARM_MATH_BIG_ENDIAN
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/* pSrc[2 * i] * pATable[2 * i] - pSrc[2 * i + 1] * pATable[2 * i + 1] */
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outR = __SMUSD(*__SIMD32(pSrc1), *__SIMD32(pCoefA));
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#else
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/* -(pSrc[2 * i + 1] * pATable[2 * i + 1] - pSrc[2 * i] * pATable[2 * i]) */
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outR = -(__SMUSD(*__SIMD32(pSrc1), *__SIMD32(pCoefA)));
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#endif /* #ifndef ARM_MATH_BIG_ENDIAN */
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/* pSrc[2 * n - 2 * i] * pBTable[2 * i] +
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pSrc[2 * n - 2 * i + 1] * pBTable[2 * i + 1]) */
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outR = __SMLAD(*__SIMD32(pSrc2), *__SIMD32(pCoefB), outR) >> 15u;
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/* pIn[2 * n - 2 * i] * pBTable[2 * i + 1] -
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pIn[2 * n - 2 * i + 1] * pBTable[2 * i] */
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#ifndef ARM_MATH_BIG_ENDIAN
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outI = __SMUSDX(*__SIMD32(pSrc2)--, *__SIMD32(pCoefB));
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#else
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outI = __SMUSDX(*__SIMD32(pCoefB), *__SIMD32(pSrc2)--);
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#endif /* #ifndef ARM_MATH_BIG_ENDIAN */
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/* (pIn[2 * i + 1] * pATable[2 * i] + pIn[2 * i] * pATable[2 * i + 1] */
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outI = __SMLADX(*__SIMD32(pSrc1)++, *__SIMD32(pCoefA), outI);
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/* write output */
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pDst[2u * i] = (q15_t) outR;
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pDst[(2u * i) + 1u] = outI >> 15u;
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/* write complex conjugate output */
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pDst[(4u * fftLen) - (2u * i)] = (q15_t) outR;
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pDst[((4u * fftLen) - (2u * i)) + 1u] = -(outI >> 15u);
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/* update coefficient pointer */
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pCoefB = pCoefB + (2u * modifier);
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pCoefA = pCoefA + (2u * modifier);
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i++;
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}
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pDst[2u * fftLen] = pSrc[0] - pSrc[1];
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pDst[(2u * fftLen) + 1u] = 0;
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pDst[0] = pSrc[0] + pSrc[1];
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pDst[1] = 0;
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#else
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/* Run the below code for Cortex-M0 */
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i = 1u;
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while(i < fftLen)
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{
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/*
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outR = (pSrc[2 * i] * pATable[2 * i] - pSrc[2 * i + 1] * pATable[2 * i + 1]
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+ pSrc[2 * n - 2 * i] * pBTable[2 * i] +
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pSrc[2 * n - 2 * i + 1] * pBTable[2 * i + 1]);
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*/
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outR = *pSrc1 * *pCoefA;
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outR = outR - (*(pSrc1 + 1) * *(pCoefA + 1));
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outR = outR + (*pSrc2 * *pCoefB);
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outR = (outR + (*(pSrc2 + 1) * *(pCoefB + 1))) >> 15;
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/* outI = (pIn[2 * i + 1] * pATable[2 * i] + pIn[2 * i] * pATable[2 * i + 1] +
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pIn[2 * n - 2 * i] * pBTable[2 * i + 1] -
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pIn[2 * n - 2 * i + 1] * pBTable[2 * i]);
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*/
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outI = *pSrc2 * *(pCoefB + 1);
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outI = outI - (*(pSrc2 + 1) * *pCoefB);
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outI = outI + (*(pSrc1 + 1) * *pCoefA);
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outI = outI + (*pSrc1 * *(pCoefA + 1));
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/* update input pointers */
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pSrc1 += 2u;
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pSrc2 -= 2u;
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/* write output */
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pDst[2u * i] = (q15_t) outR;
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pDst[(2u * i) + 1u] = outI >> 15u;
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/* write complex conjugate output */
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pDst[(4u * fftLen) - (2u * i)] = (q15_t) outR;
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pDst[((4u * fftLen) - (2u * i)) + 1u] = -(outI >> 15u);
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/* update coefficient pointer */
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pCoefB = pCoefB + (2u * modifier);
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pCoefA = pCoefA + (2u * modifier);
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i++;
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}
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pDst[2u * fftLen] = pSrc[0] - pSrc[1];
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pDst[(2u * fftLen) + 1u] = 0;
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pDst[0] = pSrc[0] + pSrc[1];
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pDst[1] = 0;
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#endif /* #ifndef ARM_MATH_CM0 */
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}
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/**
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* @brief Core Real IFFT process
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* @param[in] *pSrc points to the input buffer.
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* @param[in] fftLen length of FFT.
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* @param[in] *pATable points to the twiddle Coef A buffer.
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* @param[in] *pBTable points to the twiddle Coef B buffer.
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* @param[out] *pDst points to the output buffer.
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* @param[in] modifier twiddle coefficient modifier that supports different size FFTs with the same twiddle factor table.
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* @return none.
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* The function implements a Real IFFT
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*/
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void arm_split_rifft_q15(
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q15_t * pSrc,
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uint32_t fftLen,
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q15_t * pATable,
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q15_t * pBTable,
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q15_t * pDst,
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uint32_t modifier)
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{
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uint32_t i; /* Loop Counter */
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q31_t outR, outI; /* Temporary variables for output */
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q15_t *pCoefA, *pCoefB; /* Temporary pointers for twiddle factors */
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q15_t *pSrc1, *pSrc2;
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q15_t *pDst1 = &pDst[0];
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pCoefA = &pATable[0];
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pCoefB = &pBTable[0];
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pSrc1 = &pSrc[0];
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pSrc2 = &pSrc[2u * fftLen];
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#ifndef ARM_MATH_CM0
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/* Run the below code for Cortex-M4 and Cortex-M3 */
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i = fftLen;
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while(i > 0u)
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{
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/*
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outR = (pIn[2 * i] * pATable[2 * i] + pIn[2 * i + 1] * pATable[2 * i + 1] +
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pIn[2 * n - 2 * i] * pBTable[2 * i] -
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pIn[2 * n - 2 * i + 1] * pBTable[2 * i + 1]);
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outI = (pIn[2 * i + 1] * pATable[2 * i] - pIn[2 * i] * pATable[2 * i + 1] -
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pIn[2 * n - 2 * i] * pBTable[2 * i + 1] -
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pIn[2 * n - 2 * i + 1] * pBTable[2 * i]);
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*/
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#ifndef ARM_MATH_BIG_ENDIAN
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/* pIn[2 * n - 2 * i] * pBTable[2 * i] -
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pIn[2 * n - 2 * i + 1] * pBTable[2 * i + 1]) */
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outR = __SMUSD(*__SIMD32(pSrc2), *__SIMD32(pCoefB));
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#else
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/* -(-pIn[2 * n - 2 * i] * pBTable[2 * i] +
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pIn[2 * n - 2 * i + 1] * pBTable[2 * i + 1])) */
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outR = -(__SMUSD(*__SIMD32(pSrc2), *__SIMD32(pCoefB)));
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#endif /* #ifndef ARM_MATH_BIG_ENDIAN */
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/* pIn[2 * i] * pATable[2 * i] + pIn[2 * i + 1] * pATable[2 * i + 1] +
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pIn[2 * n - 2 * i] * pBTable[2 * i] */
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outR = __SMLAD(*__SIMD32(pSrc1), *__SIMD32(pCoefA), outR) >> 15u;
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/*
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-pIn[2 * n - 2 * i] * pBTable[2 * i + 1] +
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pIn[2 * n - 2 * i + 1] * pBTable[2 * i] */
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outI = __SMUADX(*__SIMD32(pSrc2)--, *__SIMD32(pCoefB));
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/* pIn[2 * i + 1] * pATable[2 * i] - pIn[2 * i] * pATable[2 * i + 1] */
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#ifndef ARM_MATH_BIG_ENDIAN
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outI = __SMLSDX(*__SIMD32(pCoefA), *__SIMD32(pSrc1)++, -outI);
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#else
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outI = __SMLSDX(*__SIMD32(pSrc1)++, *__SIMD32(pCoefA), -outI);
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#endif /* #ifndef ARM_MATH_BIG_ENDIAN */
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/* write output */
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#ifndef ARM_MATH_BIG_ENDIAN
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*__SIMD32(pDst1)++ = __PKHBT(outR, (outI >> 15u), 16);
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#else
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*__SIMD32(pDst1)++ = __PKHBT((outI >> 15u), outR, 16);
|
|
|
|
|
|
#endif /* #ifndef ARM_MATH_BIG_ENDIAN */
|
|
|
|
|
|
/* update coefficient pointer */
|
|
|
pCoefB = pCoefB + (2u * modifier);
|
|
|
pCoefA = pCoefA + (2u * modifier);
|
|
|
|
|
|
i--;
|
|
|
|
|
|
}
|
|
|
|
|
|
|
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|
#else
|
|
|
|
|
|
/* Run the below code for Cortex-M0 */
|
|
|
|
|
|
i = fftLen;
|
|
|
|
|
|
while(i > 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]);
|
|
|
*/
|
|
|
|
|
|
outR = *pSrc2 * *pCoefB;
|
|
|
outR = outR - (*(pSrc2 + 1) * *(pCoefB + 1));
|
|
|
outR = outR + (*pSrc1 * *pCoefA);
|
|
|
outR = (outR + (*(pSrc1 + 1) * *(pCoefA + 1))) >> 15;
|
|
|
|
|
|
/*
|
|
|
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]);
|
|
|
*/
|
|
|
|
|
|
outI = *(pSrc1 + 1) * *pCoefA;
|
|
|
outI = outI - (*pSrc1 * *(pCoefA + 1));
|
|
|
outI = outI - (*pSrc2 * *(pCoefB + 1));
|
|
|
outI = outI - (*(pSrc2 + 1) * *(pCoefB));
|
|
|
|
|
|
/* update input pointers */
|
|
|
pSrc1 += 2u;
|
|
|
pSrc2 -= 2u;
|
|
|
|
|
|
/* write output */
|
|
|
*pDst1++ = (q15_t) outR;
|
|
|
*pDst1++ = (q15_t) (outI >> 15);
|
|
|
|
|
|
/* update coefficient pointer */
|
|
|
pCoefB = pCoefB + (2u * modifier);
|
|
|
pCoefA = pCoefA + (2u * modifier);
|
|
|
|
|
|
i--;
|
|
|
|
|
|
}
|
|
|
|
|
|
#endif /* #ifndef ARM_MATH_CM0 */
|
|
|
|
|
|
}
|
|
|
|
