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Diffstat (limited to 'Drivers/CMSIS/DSP/Source/TransformFunctions/arm_rfft_q31.c')
-rw-r--r--Drivers/CMSIS/DSP/Source/TransformFunctions/arm_rfft_q31.c292
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diff --git a/Drivers/CMSIS/DSP/Source/TransformFunctions/arm_rfft_q31.c b/Drivers/CMSIS/DSP/Source/TransformFunctions/arm_rfft_q31.c
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+/* ----------------------------------------------------------------------
+ * Project: CMSIS DSP Library
+ * Title: arm_rfft_q31.c
+ * Description: FFT & RIFFT Q31 process function
+ *
+ * $Date: 18. March 2019
+ * $Revision: V1.6.0
+ *
+ * Target Processor: Cortex-M cores
+ * -------------------------------------------------------------------- */
+/*
+ * Copyright (C) 2010-2019 ARM Limited or its affiliates. All rights reserved.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Licensed under the Apache License, Version 2.0 (the License); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an AS IS BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "arm_math.h"
+
+/* ----------------------------------------------------------------------
+ * Internal functions prototypes
+ * -------------------------------------------------------------------- */
+
+void arm_split_rfft_q31(
+ q31_t * pSrc,
+ uint32_t fftLen,
+ const q31_t * pATable,
+ const q31_t * pBTable,
+ q31_t * pDst,
+ uint32_t modifier);
+
+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);
+
+/**
+ @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 input buffer
+ @param[out] pDst points to output buffer
+ @return none
+
+ @par Input an output formats
+ 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_instance_q31 *S_CFFT = S->pCfft;
+ uint32_t L2 = S->fftLenReal >> 1U;
+ uint32_t i;
+
+ /* Calculation of RIFFT of input */
+ if (S->ifftFlagR == 1U)
+ {
+ /* Real IFFT core process */
+ arm_split_rifft_q31 (pSrc, L2, S->pTwiddleAReal, S->pTwiddleBReal, pDst, S->twidCoefRModifier);
+
+ /* Complex IFFT process */
+ arm_cfft_q31 (S_CFFT, pDst, S->ifftFlagR, S->bitReverseFlagR);
+
+ for(i = 0; i < S->fftLenReal; i++)
+ {
+ pDst[i] = pDst[i] << 1U;
+ }
+ }
+ else
+ {
+ /* Calculation of RFFT of input */
+
+ /* Complex FFT process */
+ arm_cfft_q31 (S_CFFT, pSrc, S->ifftFlagR, S->bitReverseFlagR);
+
+ /* Real FFT core process */
+ arm_split_rfft_q31 (pSrc, L2, S->pTwiddleAReal, S->pTwiddleBReal, pDst, S->twidCoefRModifier);
+ }
+
+}
+
+/**
+ @} end of RealFFT group
+ */
+
+/**
+ @brief Core Real FFT process
+ @param[in] pSrc points to input buffer
+ @param[in] fftLen length of FFT
+ @param[in] pATable points to twiddle Coef A buffer
+ @param[in] pBTable points to twiddle Coef B buffer
+ @param[out] pDst points to 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,
+ const q31_t * pATable,
+ const q31_t * pBTable,
+ q31_t * pDst,
+ uint32_t modifier)
+{
+ uint32_t i; /* Loop Counter */
+ 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 *pOut1 = &pDst[2], *pOut2 = &pDst[4 * fftLen - 1];
+ q31_t *pIn1 = &pSrc[2], *pIn2 = &pSrc[2 * fftLen - 1];
+
+ /* Init coefficient pointers */
+ pCoefA = &pATable[modifier * 2];
+ pCoefB = &pBTable[modifier * 2];
+
+ 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] */
+ mult_32x32_keep32_R (outR, *pIn1, CoefA1);
+
+ /* outI = pIn[2 * i] * pATable[2 * i + 1] */
+ mult_32x32_keep32_R (outI, *pIn1++, CoefA2);
+
+ /* - pSrc[2 * i + 1] * pATable[2 * i + 1] */
+ multSub_32x32_keep32_R (outR, *pIn1, CoefA2);
+
+ /* (pIn[2 * i + 1] * pATable[2 * i] */
+ multAcc_32x32_keep32_R (outI, *pIn1++, CoefA1);
+
+ /* pSrc[2 * n - 2 * i] * pBTable[2 * i] */
+ multSub_32x32_keep32_R (outR, *pIn2, CoefA2);
+ CoefB1 = *pCoefB;
+
+ /* pIn[2 * n - 2 * i] * pBTable[2 * i + 1] */
+ multSub_32x32_keep32_R (outI, *pIn2--, CoefB1);
+
+ /* pSrc[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] */
+ multSub_32x32_keep32_R (outI, *pIn2--, CoefA2);
+
+ /* write output */
+ *pOut1++ = outR;
+ *pOut1++ = outI;
+
+ /* write complex conjugate output */
+ *pOut2-- = -outI;
+ *pOut2-- = outR;
+
+ /* update coefficient pointer */
+ pCoefB = pCoefB + (2 * modifier);
+ pCoefA = pCoefA + (2 * modifier - 1);
+
+ /* Decrement loop count */
+ i--;
+ }
+
+ pDst[2 * fftLen] = (pSrc[0] - pSrc[1]) >> 1U;
+ pDst[2 * fftLen + 1] = 0;
+
+ pDst[0] = (pSrc[0] + pSrc[1]) >> 1U;
+ pDst[1] = 0;
+}
+
+
+/**
+ @brief Core Real IFFT process
+ @param[in] pSrc points to input buffer
+ @param[in] fftLen length of FFT
+ @param[in] pATable points to twiddle Coef A buffer
+ @param[in] pBTable points to twiddle Coef B buffer
+ @param[out] pDst points to 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,
+ 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--;
+ }
+
+}
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