431 lines
14 KiB
C
431 lines
14 KiB
C
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/* ----------------------------------------------------------------------
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* Project: CMSIS DSP Library
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* Title: arm_rfft_q31.c
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* Description: FFT & RIFFT Q31 process function
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*
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* $Date: 23 April 2021
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* $Revision: V1.9.0
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*
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* Target Processor: Cortex-M and Cortex-A cores
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* -------------------------------------------------------------------- */
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/*
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* Copyright (C) 2010-2021 ARM Limited or its affiliates. All rights reserved.
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*
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* SPDX-License-Identifier: Apache-2.0
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*
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* Licensed under the Apache License, Version 2.0 (the License); you may
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* not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an AS IS BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "dsp/transform_functions.h"
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/* ----------------------------------------------------------------------
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* Internal functions prototypes
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* -------------------------------------------------------------------- */
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void arm_split_rfft_q31(
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q31_t * pSrc,
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uint32_t fftLen,
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const q31_t * pATable,
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const q31_t * pBTable,
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q31_t * pDst,
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uint32_t modifier);
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void arm_split_rifft_q31(
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q31_t * pSrc,
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uint32_t fftLen,
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const q31_t * pATable,
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const q31_t * pBTable,
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q31_t * pDst,
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uint32_t modifier);
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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 Processing function for the Q31 RFFT/RIFFT.
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@param[in] S points to an instance of the Q31 RFFT/RIFFT structure
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@param[in] pSrc points to input buffer (Source buffer is modified by this function)
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@param[out] pDst points to output buffer
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@return none
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@par Input an output formats
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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 RFFTQ31.gif "Input and Output Formats for Q31 RFFT"
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@par
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\image html RIFFTQ31.gif "Input and Output Formats for Q31 RIFFT"
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@par
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If the input buffer is of length N, the output buffer must have length 2*N.
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The input buffer is modified by this function.
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@par
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For the RIFFT, the source buffer must at least have length
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fftLenReal + 2.
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The last two elements must be equal to what would be generated
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by the RFFT:
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(pSrc[0] - pSrc[1]) >> 1 and 0
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*/
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void arm_rfft_q31(
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const arm_rfft_instance_q31 * S,
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q31_t * pSrc,
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q31_t * pDst)
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{
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#if defined(ARM_MATH_MVEI) && !defined(ARM_MATH_AUTOVECTORIZE)
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const arm_cfft_instance_q31 *S_CFFT = &(S->cfftInst);
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#else
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const arm_cfft_instance_q31 *S_CFFT = S->pCfft;
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#endif
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uint32_t L2 = S->fftLenReal >> 1U;
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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_q31 (pSrc, L2, S->pTwiddleAReal, S->pTwiddleBReal, pDst, S->twidCoefRModifier);
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/* Complex IFFT process */
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arm_cfft_q31 (S_CFFT, pDst, S->ifftFlagR, S->bitReverseFlagR);
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arm_shift_q31(pDst, 1, pDst, S->fftLenReal);
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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 FFT process */
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arm_cfft_q31 (S_CFFT, pSrc, S->ifftFlagR, S->bitReverseFlagR);
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/* Real FFT core process */
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arm_split_rfft_q31 (pSrc, L2, S->pTwiddleAReal, S->pTwiddleBReal, pDst, S->twidCoefRModifier);
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}
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}
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/**
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@} end of RealFFT group
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*/
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/**
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@brief Core Real FFT process
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@param[in] pSrc points to input buffer
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@param[in] fftLen length of FFT
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@param[in] pATable points to twiddle Coef A buffer
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@param[in] pBTable points to twiddle Coef B buffer
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@param[out] pDst points to 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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*/
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#if defined(ARM_MATH_MVEI) && !defined(ARM_MATH_AUTOVECTORIZE)
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#include "arm_helium_utils.h"
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#include "arm_vec_fft.h"
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#if defined(__CMSIS_GCC_H)
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#define MVE_CMPLX_MULT_FX_AxB_S32(A,B) vqdmladhxq_s32(vqdmlsdhq_s32((__typeof(A))vuninitializedq_s32(), A, B), A, B)
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#define MVE_CMPLX_MULT_FX_AxConjB_S32(A,B) vqdmladhq_s32(vqdmlsdhxq_s32((__typeof(A))vuninitializedq_s32(), A, B), A, B)
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#endif
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void arm_split_rfft_q31(
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q31_t *pSrc,
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uint32_t fftLen,
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const q31_t *pATable,
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const q31_t *pBTable,
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q31_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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const q31_t *pCoefA, *pCoefB; /* Temporary pointers for twiddle factors */
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q31_t *pOut1 = &pDst[2];
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q31_t *pIn1 = &pSrc[2];
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uint32x4_t offset = { 2, 3, 0, 1 };
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uint32x4_t offsetCoef = { 0, 1, modifier * 2, modifier * 2 + 1 };
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offset = offset + (2 * fftLen - 4);
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/* Init coefficient pointers */
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pCoefA = &pATable[modifier * 2];
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pCoefB = &pBTable[modifier * 2];
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const q31_t *pCoefAb, *pCoefBb;
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pCoefAb = pCoefA;
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pCoefBb = pCoefB;
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pIn1 = &pSrc[2];
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i = fftLen - 1U;
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i = i / 2 + 1;
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while (i > 0U) {
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q31x4_t in1 = vld1q_s32(pIn1);
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q31x4_t in2 = vldrwq_gather_shifted_offset_s32(pSrc, offset);
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q31x4_t coefA = vldrwq_gather_shifted_offset_s32(pCoefAb, offsetCoef);
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q31x4_t coefB = vldrwq_gather_shifted_offset_s32(pCoefBb, offsetCoef);
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#if defined(__CMSIS_GCC_H)
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q31x4_t out = vhaddq_s32(MVE_CMPLX_MULT_FX_AxB_S32(in1, coefA),MVE_CMPLX_MULT_FX_AxConjB_S32(coefB, in2));
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#else
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q31x4_t out = vhaddq_s32(MVE_CMPLX_MULT_FX_AxB(in1, coefA, q31x4_t),
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MVE_CMPLX_MULT_FX_AxConjB(coefB, in2, q31x4_t));
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#endif
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vst1q(pOut1, out);
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pOut1 += 4;
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offsetCoef += modifier * 4;
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offset -= 4;
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pIn1 += 4;
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i -= 1;
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}
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pDst[2 * fftLen] = (pSrc[0] - pSrc[1]) >> 1U;
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pDst[2 * fftLen + 1] = 0;
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pDst[0] = (pSrc[0] + pSrc[1]) >> 1U;
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pDst[1] = 0;
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}
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#else
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void arm_split_rfft_q31(
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q31_t * pSrc,
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uint32_t fftLen,
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const q31_t * pATable,
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const q31_t * pBTable,
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q31_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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const q31_t *pCoefA, *pCoefB; /* Temporary pointers for twiddle factors */
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q31_t CoefA1, CoefA2, CoefB1; /* Temporary variables for twiddle coefficients */
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q31_t *pOut1 = &pDst[2], *pOut2 = &pDst[4 * fftLen - 1];
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q31_t *pIn1 = &pSrc[2], *pIn2 = &pSrc[2 * fftLen - 1];
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/* Init coefficient pointers */
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pCoefA = &pATable[modifier * 2];
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pCoefB = &pBTable[modifier * 2];
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i = fftLen - 1U;
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while (i > 0U)
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{
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/*
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outR = ( pSrc[2 * i] * pATable[2 * i]
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- 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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outI = ( pIn[2 * i + 1] * pATable[2 * i]
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+ 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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CoefA1 = *pCoefA++;
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CoefA2 = *pCoefA;
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/* outR = (pSrc[2 * i] * pATable[2 * i] */
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mult_32x32_keep32_R (outR, *pIn1, CoefA1);
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/* outI = pIn[2 * i] * pATable[2 * i + 1] */
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mult_32x32_keep32_R (outI, *pIn1++, CoefA2);
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/* - pSrc[2 * i + 1] * pATable[2 * i + 1] */
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multSub_32x32_keep32_R (outR, *pIn1, CoefA2);
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/* (pIn[2 * i + 1] * pATable[2 * i] */
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multAcc_32x32_keep32_R (outI, *pIn1++, CoefA1);
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/* pSrc[2 * n - 2 * i] * pBTable[2 * i] */
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multSub_32x32_keep32_R (outR, *pIn2, CoefA2);
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CoefB1 = *pCoefB;
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/* pIn[2 * n - 2 * i] * pBTable[2 * i + 1] */
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multSub_32x32_keep32_R (outI, *pIn2--, CoefB1);
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/* pSrc[2 * n - 2 * i + 1] * pBTable[2 * i + 1] */
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multAcc_32x32_keep32_R (outR, *pIn2, CoefB1);
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/* pIn[2 * n - 2 * i + 1] * pBTable[2 * i] */
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multSub_32x32_keep32_R (outI, *pIn2--, CoefA2);
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/* write output */
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*pOut1++ = outR;
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*pOut1++ = outI;
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/* write complex conjugate output */
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*pOut2-- = -outI;
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*pOut2-- = outR;
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/* update coefficient pointer */
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pCoefB = pCoefB + (2 * modifier);
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pCoefA = pCoefA + (2 * modifier - 1);
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/* Decrement loop count */
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i--;
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}
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pDst[2 * fftLen] = (pSrc[0] - pSrc[1]) >> 1U;
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pDst[2 * fftLen + 1] = 0;
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pDst[0] = (pSrc[0] + pSrc[1]) >> 1U;
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pDst[1] = 0;
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}
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#endif /* defined(ARM_MATH_MVEI) */
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/**
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@brief Core Real IFFT process
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@param[in] pSrc points to input buffer
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@param[in] fftLen length of FFT
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@param[in] pATable points to twiddle Coef A buffer
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@param[in] pBTable points to twiddle Coef B buffer
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@param[out] pDst points to 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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*/
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#if defined(ARM_MATH_MVEI) && !defined(ARM_MATH_AUTOVECTORIZE)
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void arm_split_rifft_q31(
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q31_t * pSrc,
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uint32_t fftLen,
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const q31_t * pATable,
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const q31_t * pBTable,
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q31_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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const q31_t *pCoefA, *pCoefB; /* Temporary pointers for twiddle factors */
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q31_t *pIn1;
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uint32x4_t offset = { 2, 3, 0, 1 };
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uint32x4_t offsetCoef = { 0, 1, modifier * 2, modifier * 2 + 1 };
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int32x4_t conj = { 1, -1, 1, -1 };
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offset = offset + (2 * fftLen - 2);
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/* Init coefficient pointers */
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pCoefA = &pATable[0];
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pCoefB = &pBTable[0];
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const q31_t *pCoefAb, *pCoefBb;
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pCoefAb = pCoefA;
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pCoefBb = pCoefB;
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pIn1 = &pSrc[0];
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i = fftLen;
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i = i >> 1;
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while (i > 0U) {
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q31x4_t in1 = vld1q_s32(pIn1);
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q31x4_t in2 = vldrwq_gather_shifted_offset_s32(pSrc, offset);
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q31x4_t coefA = vldrwq_gather_shifted_offset_s32(pCoefAb, offsetCoef);
|
||
|
|
q31x4_t coefB = vldrwq_gather_shifted_offset_s32(pCoefBb, offsetCoef);
|
||
|
|
|
||
|
|
/* can we avoid the conjugate here ? */
|
||
|
|
#if defined(__CMSIS_GCC_H)
|
||
|
|
q31x4_t out = vhaddq_s32(MVE_CMPLX_MULT_FX_AxConjB_S32(in1, coefA),
|
||
|
|
vmulq_s32(conj, MVE_CMPLX_MULT_FX_AxB_S32(in2, coefB)));
|
||
|
|
#else
|
||
|
|
q31x4_t out = vhaddq_s32(MVE_CMPLX_MULT_FX_AxConjB(in1, coefA, q31x4_t),
|
||
|
|
vmulq_s32(conj, MVE_CMPLX_MULT_FX_AxB(in2, coefB, q31x4_t)));
|
||
|
|
#endif
|
||
|
|
vst1q_s32(pDst, out);
|
||
|
|
pDst += 4;
|
||
|
|
|
||
|
|
offsetCoef += modifier * 4;
|
||
|
|
offset -= 4;
|
||
|
|
|
||
|
|
pIn1 += 4;
|
||
|
|
i -= 1;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
#else
|
||
|
|
void arm_split_rifft_q31(
|
||
|
|
q31_t * pSrc,
|
||
|
|
uint32_t fftLen,
|
||
|
|
const q31_t * pATable,
|
||
|
|
const q31_t * pBTable,
|
||
|
|
q31_t * pDst,
|
||
|
|
uint32_t modifier)
|
||
|
|
{
|
||
|
|
q31_t outR, outI; /* Temporary variables for output */
|
||
|
|
const 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[2 * fftLen + 1];
|
||
|
|
|
||
|
|
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] */
|
||
|
|
mult_32x32_keep32_R (outR, *pIn1, CoefA1);
|
||
|
|
|
||
|
|
/* - pIn[2 * i] * pATable[2 * i + 1] */
|
||
|
|
mult_32x32_keep32_R (outI, *pIn1++, -CoefA2);
|
||
|
|
|
||
|
|
/* pIn[2 * i + 1] * pATable[2 * i + 1] */
|
||
|
|
multAcc_32x32_keep32_R (outR, *pIn1, CoefA2);
|
||
|
|
|
||
|
|
/* pIn[2 * i + 1] * pATable[2 * i] */
|
||
|
|
multAcc_32x32_keep32_R (outI, *pIn1++, CoefA1);
|
||
|
|
|
||
|
|
/* pIn[2 * n - 2 * i] * pBTable[2 * i] */
|
||
|
|
multAcc_32x32_keep32_R (outR, *pIn2, CoefA2);
|
||
|
|
CoefB1 = *pCoefB;
|
||
|
|
|
||
|
|
/* pIn[2 * n - 2 * i] * pBTable[2 * i + 1] */
|
||
|
|
multSub_32x32_keep32_R (outI, *pIn2--, CoefB1);
|
||
|
|
|
||
|
|
/* pIn[2 * n - 2 * i + 1] * pBTable[2 * i + 1] */
|
||
|
|
multAcc_32x32_keep32_R (outR, *pIn2, CoefB1);
|
||
|
|
|
||
|
|
/* pIn[2 * n - 2 * i + 1] * pBTable[2 * i] */
|
||
|
|
multAcc_32x32_keep32_R (outI, *pIn2--, CoefA2);
|
||
|
|
|
||
|
|
/* write output */
|
||
|
|
*pDst++ = outR;
|
||
|
|
*pDst++ = outI;
|
||
|
|
|
||
|
|
/* update coefficient pointer */
|
||
|
|
pCoefB = pCoefB + (modifier * 2);
|
||
|
|
pCoefA = pCoefA + (modifier * 2 - 1);
|
||
|
|
|
||
|
|
/* Decrement loop count */
|
||
|
|
fftLen--;
|
||
|
|
}
|
||
|
|
|
||
|
|
}
|
||
|
|
|
||
|
|
#endif /* defined(ARM_MATH_MVEI) */
|