diff options
Diffstat (limited to 'Drivers/CMSIS/DSP/Source/TransformFunctions/arm_rfft_q15.c')
| -rw-r--r-- | Drivers/CMSIS/DSP/Source/TransformFunctions/arm_rfft_q15.c | 380 |
1 files changed, 380 insertions, 0 deletions
diff --git a/Drivers/CMSIS/DSP/Source/TransformFunctions/arm_rfft_q15.c b/Drivers/CMSIS/DSP/Source/TransformFunctions/arm_rfft_q15.c new file mode 100644 index 0000000..29d12b7 --- /dev/null +++ b/Drivers/CMSIS/DSP/Source/TransformFunctions/arm_rfft_q15.c @@ -0,0 +1,380 @@ +/* ----------------------------------------------------------------------
+ * Project: CMSIS DSP Library
+ * Title: arm_rfft_q15.c
+ * Description: RFFT & RIFFT Q15 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_q15(
+ q15_t * pSrc,
+ uint32_t fftLen,
+ const q15_t * pATable,
+ const q15_t * pBTable,
+ q15_t * pDst,
+ uint32_t modifier);
+
+void arm_split_rifft_q15(
+ q15_t * pSrc,
+ uint32_t fftLen,
+ const q15_t * pATable,
+ const q15_t * pBTable,
+ q15_t * pDst,
+ uint32_t modifier);
+
+/**
+ @addtogroup RealFFT
+ @{
+ */
+
+/**
+ @brief Processing function for the Q15 RFFT/RIFFT.
+ @param[in] S points to an instance of the Q15 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 RFFTQ15.gif "Input and Output Formats for Q15 RFFT"
+ @par
+ \image html RIFFTQ15.gif "Input and Output Formats for Q15 RIFFT"
+ */
+
+void arm_rfft_q15(
+ const arm_rfft_instance_q15 * S,
+ q15_t * pSrc,
+ q15_t * pDst)
+{
+ const arm_cfft_instance_q15 *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_q15 (pSrc, L2, S->pTwiddleAReal, S->pTwiddleBReal, pDst, S->twidCoefRModifier);
+
+ /* Complex IFFT process */
+ arm_cfft_q15 (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_q15 (S_CFFT, pSrc, S->ifftFlagR, S->bitReverseFlagR);
+
+ /* Real FFT core process */
+ arm_split_rfft_q15 (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
+
+ @par
+ The function implements a Real FFT
+ */
+
+void arm_split_rfft_q15(
+ q15_t * pSrc,
+ uint32_t fftLen,
+ const q15_t * pATable,
+ const q15_t * pBTable,
+ q15_t * pDst,
+ uint32_t modifier)
+{
+ uint32_t i; /* Loop Counter */
+ q31_t outR, outI; /* Temporary variables for output */
+ const q15_t *pCoefA, *pCoefB; /* Temporary pointers for twiddle factors */
+ q15_t *pSrc1, *pSrc2;
+#if defined (ARM_MATH_DSP)
+ q15_t *pD1, *pD2;
+#endif
+
+ /* Init coefficient pointers */
+ pCoefA = &pATable[modifier * 2];
+ pCoefB = &pBTable[modifier * 2];
+
+ pSrc1 = &pSrc[2];
+ pSrc2 = &pSrc[(2U * fftLen) - 2U];
+
+#if defined (ARM_MATH_DSP)
+
+ i = 1U;
+ pD1 = pDst + 2;
+ pD2 = pDst + (4U * fftLen) - 2;
+
+ for (i = fftLen - 1; i > 0; i--)
+ {
+ /*
+ 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])
+ */
+
+
+#ifndef ARM_MATH_BIG_ENDIAN
+ /* pSrc[2 * i] * pATable[2 * i] - pSrc[2 * i + 1] * pATable[2 * i + 1] */
+ outR = __SMUSD(read_q15x2 (pSrc1), read_q15x2((q15_t *) pCoefA));
+#else
+ /* -(pSrc[2 * i + 1] * pATable[2 * i + 1] - pSrc[2 * i] * pATable[2 * i]) */
+ outR = -(__SMUSD(read_q15x2 (pSrc1), read_q15x2((q15_t *) pCoefA)));
+#endif /* #ifndef ARM_MATH_BIG_ENDIAN */
+
+ /* pSrc[2 * n - 2 * i] * pBTable[2 * i] + pSrc[2 * n - 2 * i + 1] * pBTable[2 * i + 1]) */
+ outR = __SMLAD(read_q15x2 (pSrc2), read_q15x2((q15_t *) pCoefB), outR) >> 16U;
+
+ /* pIn[2 * n - 2 * i] * pBTable[2 * i + 1] - pIn[2 * n - 2 * i + 1] * pBTable[2 * i] */
+#ifndef ARM_MATH_BIG_ENDIAN
+ outI = __SMUSDX(read_q15x2_da (&pSrc2), read_q15x2((q15_t *) pCoefB));
+#else
+ outI = __SMUSDX(read_q15x2 ((q15_t *) pCoefB), read_q15x2_da (&pSrc2));
+#endif /* #ifndef ARM_MATH_BIG_ENDIAN */
+
+ /* (pIn[2 * i + 1] * pATable[2 * i] + pIn[2 * i] * pATable[2 * i + 1] */
+ outI = __SMLADX(read_q15x2_ia (&pSrc1), read_q15x2 ((q15_t *) pCoefA), outI);
+
+ /* write output */
+ *pD1++ = (q15_t) outR;
+ *pD1++ = outI >> 16U;
+
+ /* write complex conjugate output */
+ pD2[0] = (q15_t) outR;
+ pD2[1] = -(outI >> 16U);
+ pD2 -= 2;
+
+ /* update coefficient pointer */
+ pCoefB = pCoefB + (2U * modifier);
+ pCoefA = pCoefA + (2U * modifier);
+ }
+
+ pDst[2U * fftLen] = (pSrc[0] - pSrc[1]) >> 1U;
+ pDst[2U * fftLen + 1U] = 0;
+
+ pDst[0] = (pSrc[0] + pSrc[1]) >> 1U;
+ pDst[1] = 0;
+
+#else
+
+ i = 1U;
+
+ while (i < fftLen)
+ {
+ /*
+ 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]);
+ */
+
+ outR = *pSrc1 * *pCoefA;
+ outR = outR - (*(pSrc1 + 1) * *(pCoefA + 1));
+ outR = outR + (*pSrc2 * *pCoefB);
+ outR = (outR + (*(pSrc2 + 1) * *(pCoefB + 1))) >> 16;
+
+ /*
+ 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 = *pSrc2 * *(pCoefB + 1);
+ outI = outI - (*(pSrc2 + 1) * *pCoefB);
+ outI = outI + (*(pSrc1 + 1) * *pCoefA);
+ outI = outI + (*pSrc1 * *(pCoefA + 1));
+
+ /* update input pointers */
+ pSrc1 += 2U;
+ pSrc2 -= 2U;
+
+ /* write output */
+ pDst[2U * i] = (q15_t) outR;
+ pDst[2U * i + 1U] = outI >> 16U;
+
+ /* write complex conjugate output */
+ pDst[(4U * fftLen) - (2U * i)] = (q15_t) outR;
+ pDst[((4U * fftLen) - (2U * i)) + 1U] = -(outI >> 16U);
+
+ /* update coefficient pointer */
+ pCoefB = pCoefB + (2U * modifier);
+ pCoefA = pCoefA + (2U * modifier);
+
+ i++;
+ }
+
+ pDst[2U * fftLen] = (pSrc[0] - pSrc[1]) >> 1;
+ pDst[2U * fftLen + 1U] = 0;
+
+ pDst[0] = (pSrc[0] + pSrc[1]) >> 1;
+ pDst[1] = 0;
+
+#endif /* #if defined (ARM_MATH_DSP) */
+}
+
+
+/**
+ @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
+
+ @par
+ The function implements a Real IFFT
+ */
+
+void arm_split_rifft_q15(
+ q15_t * pSrc,
+ uint32_t fftLen,
+ const q15_t * pATable,
+ const q15_t * pBTable,
+ q15_t * pDst,
+ uint32_t modifier)
+{
+ uint32_t i; /* Loop Counter */
+ q31_t outR, outI; /* Temporary variables for output */
+ const q15_t *pCoefA, *pCoefB; /* Temporary pointers for twiddle factors */
+ q15_t *pSrc1, *pSrc2;
+ q15_t *pDst1 = &pDst[0];
+
+ pCoefA = &pATable[0];
+ pCoefB = &pBTable[0];
+
+ pSrc1 = &pSrc[0];
+ pSrc2 = &pSrc[2 * fftLen];
+
+ 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]);
+
+ 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]);
+ */
+
+#if defined (ARM_MATH_DSP)
+
+#ifndef ARM_MATH_BIG_ENDIAN
+ /* pIn[2 * n - 2 * i] * pBTable[2 * i] - pIn[2 * n - 2 * i + 1] * pBTable[2 * i + 1]) */
+ outR = __SMUSD(read_q15x2(pSrc2), read_q15x2((q15_t *) pCoefB));
+#else
+ /* -(-pIn[2 * n - 2 * i] * pBTable[2 * i] + pIn[2 * n - 2 * i + 1] * pBTable[2 * i + 1])) */
+ outR = -(__SMUSD(read_q15x2(pSrc2), read_q15x2((q15_t *) pCoefB)));
+#endif /* #ifndef ARM_MATH_BIG_ENDIAN */
+
+ /* pIn[2 * i] * pATable[2 * i] + pIn[2 * i + 1] * pATable[2 * i + 1] + pIn[2 * n - 2 * i] * pBTable[2 * i] */
+ outR = __SMLAD(read_q15x2(pSrc1), read_q15x2 ((q15_t *) pCoefA), outR) >> 16U;
+
+ /* -pIn[2 * n - 2 * i] * pBTable[2 * i + 1] + pIn[2 * n - 2 * i + 1] * pBTable[2 * i] */
+ outI = __SMUADX(read_q15x2_da (&pSrc2), read_q15x2((q15_t *) pCoefB));
+
+ /* pIn[2 * i + 1] * pATable[2 * i] - pIn[2 * i] * pATable[2 * i + 1] */
+#ifndef ARM_MATH_BIG_ENDIAN
+ outI = __SMLSDX(read_q15x2 ((q15_t *) pCoefA), read_q15x2_ia (&pSrc1), -outI);
+#else
+ outI = __SMLSDX(read_q15x2_ia (&pSrc1), read_q15x2 ((q15_t *) pCoefA), -outI);
+#endif /* #ifndef ARM_MATH_BIG_ENDIAN */
+
+ /* write output */
+#ifndef ARM_MATH_BIG_ENDIAN
+ write_q15x2_ia (&pDst1, __PKHBT(outR, (outI >> 16U), 16));
+#else
+ write_q15x2_ia (&pDst1, __PKHBT((outI >> 16U), outR, 16));
+#endif /* #ifndef ARM_MATH_BIG_ENDIAN */
+
+
+#else /* #if defined (ARM_MATH_DSP) */
+
+ outR = *pSrc2 * *pCoefB;
+ outR = outR - (*(pSrc2 + 1) * *(pCoefB + 1));
+ outR = outR + (*pSrc1 * *pCoefA);
+ outR = (outR + (*(pSrc1 + 1) * *(pCoefA + 1))) >> 16;
+
+ 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 >> 16);
+
+#endif /* #if defined (ARM_MATH_DSP) */
+
+ /* update coefficient pointer */
+ pCoefB = pCoefB + (2 * modifier);
+ pCoefA = pCoefA + (2 * modifier);
+
+ i--;
+ }
+
+}
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