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Diffstat (limited to 'apps/mathlib/CMSIS/DSP_Lib/Source/TransformFunctions/arm_cfft_radix4_f32.c')
| -rw-r--r-- | apps/mathlib/CMSIS/DSP_Lib/Source/TransformFunctions/arm_cfft_radix4_f32.c | 1236 |
1 files changed, 0 insertions, 1236 deletions
diff --git a/apps/mathlib/CMSIS/DSP_Lib/Source/TransformFunctions/arm_cfft_radix4_f32.c b/apps/mathlib/CMSIS/DSP_Lib/Source/TransformFunctions/arm_cfft_radix4_f32.c deleted file mode 100644 index d51e9830b..000000000 --- a/apps/mathlib/CMSIS/DSP_Lib/Source/TransformFunctions/arm_cfft_radix4_f32.c +++ /dev/null @@ -1,1236 +0,0 @@ -/* ----------------------------------------------------------------------
-* Copyright (C) 2010 ARM Limited. All rights reserved.
-*
-* $Date: 15. February 2012
-* $Revision: V1.1.0
-*
-* Project: CMSIS DSP Library
-* Title: arm_cfft_radix4_f32.c
-*
-* Description: Radix-4 Decimation in Frequency CFFT & CIFFT Floating point processing function
-*
-*
-* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
-*
-* Version 1.1.0 2012/02/15
-* Updated with more optimizations, bug fixes and minor API changes.
-*
-* Version 1.0.10 2011/7/15
-* Big Endian support added and Merged M0 and M3/M4 Source code.
-*
-* Version 1.0.3 2010/11/29
-* Re-organized the CMSIS folders and updated documentation.
-*
-* Version 1.0.2 2010/11/11
-* Documentation updated.
-*
-* Version 1.0.1 2010/10/05
-* Production release and review comments incorporated.
-*
-* Version 1.0.0 2010/09/20
-* Production release and review comments incorporated.
-*
-* Version 0.0.5 2010/04/26
-* incorporated review comments and updated with latest CMSIS layer
-*
-* Version 0.0.3 2010/03/10
-* Initial version
-* -------------------------------------------------------------------- */
-
-#include "arm_math.h"
-
-/**
- * @ingroup groupTransforms
- */
-
-/**
- * @defgroup Radix4_CFFT_CIFFT Radix-4 Complex FFT Functions
- *
- * \par
- * Complex Fast Fourier Transform(CFFT) and Complex Inverse Fast Fourier Transform(CIFFT) is an efficient algorithm to compute Discrete Fourier Transform(DFT) and Inverse Discrete Fourier Transform(IDFT).
- * Computational complexity of CFFT reduces drastically when compared to DFT.
- * \par
- * This set of functions implements CFFT/CIFFT
- * for Q15, Q31, and floating-point data types. The functions operates on in-place buffer which uses same buffer for input and output.
- * Complex input is stored in input buffer in an interleaved fashion.
- *
- * \par
- * The functions operate on blocks of input and output data and each call to the function processes
- * <code>2*fftLen</code> samples through the transform. <code>pSrc</code> points to In-place arrays containing <code>2*fftLen</code> values.
- * \par
- * The <code>pSrc</code> points to the array of in-place buffer of size <code>2*fftLen</code> and inputs and outputs are stored in an interleaved fashion as shown below.
- * <pre> {real[0], imag[0], real[1], imag[1],..} </pre>
- *
- * \par Lengths supported by the transform:
- * \par
- * Internally, the function utilize a radix-4 decimation in frequency(DIF) algorithm
- * and the size of the FFT supported are of the lengths [16, 64, 256, 1024].
- *
- *
- * \par Algorithm:
- *
- * <b>Complex Fast Fourier Transform:</b>
- * \par
- * Input real and imaginary data:
- * <pre>
- * x(n) = xa + j * ya
- * x(n+N/4 ) = xb + j * yb
- * x(n+N/2 ) = xc + j * yc
- * x(n+3N 4) = xd + j * yd
- * </pre>
- * where N is length of FFT
- * \par
- * Output real and imaginary data:
- * <pre>
- * X(4r) = xa'+ j * ya'
- * X(4r+1) = xb'+ j * yb'
- * X(4r+2) = xc'+ j * yc'
- * X(4r+3) = xd'+ j * yd'
- * </pre>
- * \par
- * Twiddle factors for radix-4 FFT:
- * <pre>
- * Wn = co1 + j * (- si1)
- * W2n = co2 + j * (- si2)
- * W3n = co3 + j * (- si3)
- * </pre>
- *
- * \par
- * \image html CFFT.gif "Radix-4 Decimation-in Frequency Complex Fast Fourier Transform"
- *
- * \par
- * Output from Radix-4 CFFT Results in Digit reversal order. Interchange middle two branches of every butterfly results in Bit reversed output.
- * \par
- * <b> Butterfly CFFT equations:</b>
- * <pre>
- * xa' = xa + xb + xc + xd
- * ya' = ya + yb + yc + yd
- * xc' = (xa+yb-xc-yd)* co1 + (ya-xb-yc+xd)* (si1)
- * yc' = (ya-xb-yc+xd)* co1 - (xa+yb-xc-yd)* (si1)
- * xb' = (xa-xb+xc-xd)* co2 + (ya-yb+yc-yd)* (si2)
- * yb' = (ya-yb+yc-yd)* co2 - (xa-xb+xc-xd)* (si2)
- * xd' = (xa-yb-xc+yd)* co3 + (ya+xb-yc-xd)* (si3)
- * yd' = (ya+xb-yc-xd)* co3 - (xa-yb-xc+yd)* (si3)
- * </pre>
- *
- *
- * <b>Complex Inverse Fast Fourier Transform:</b>
- * \par
- * CIFFT uses same twiddle factor table as CFFT with modifications in the design equation as shown below.
- *
- * \par
- * <b> Modified Butterfly CIFFT equations:</b>
- * <pre>
- * xa' = xa + xb + xc + xd
- * ya' = ya + yb + yc + yd
- * xc' = (xa-yb-xc+yd)* co1 - (ya+xb-yc-xd)* (si1)
- * yc' = (ya+xb-yc-xd)* co1 + (xa-yb-xc+yd)* (si1)
- * xb' = (xa-xb+xc-xd)* co2 - (ya-yb+yc-yd)* (si2)
- * yb' = (ya-yb+yc-yd)* co2 + (xa-xb+xc-xd)* (si2)
- * xd' = (xa+yb-xc-yd)* co3 - (ya-xb-yc+xd)* (si3)
- * yd' = (ya-xb-yc+xd)* co3 + (xa+yb-xc-yd)* (si3)
- * </pre>
- *
- * \par Instance Structure
- * A separate instance structure must be defined for each Instance but the twiddle factors and bit reversal tables can be reused.
- * There are separate instance structure declarations for each of the 3 supported data types.
- *
- * \par Initialization Functions
- * There is also an associated initialization function for each data type.
- * The initialization function performs the following operations:
- * - Sets the values of the internal structure fields.
- * - Initializes twiddle factor table and bit reversal table pointers
- * \par
- * Use of the initialization function is optional.
- * However, if the initialization function is used, then the instance structure cannot be placed into a const data section.
- * To place an instance structure into a const data section, the instance structure must be manually initialized.
- * Manually initialize the instance structure as follows:
- * <pre>
- *arm_cfft_radix4_instance_f32 S = {fftLen, ifftFlag, bitReverseFlag, pTwiddle, pBitRevTable, twidCoefModifier, bitRevFactor, onebyfftLen};
- *arm_cfft_radix4_instance_q31 S = {fftLen, ifftFlag, bitReverseFlag, pTwiddle, pBitRevTable, twidCoefModifier, bitRevFactor};
- *arm_cfft_radix4_instance_q15 S = {fftLen, ifftFlag, bitReverseFlag, pTwiddle, pBitRevTable, twidCoefModifier, bitRevFactor};
- * </pre>
- * \par
- * where <code>fftLen</code> length of CFFT/CIFFT; <code>ifftFlag</code> Flag for selection of CFFT or CIFFT(Set ifftFlag to calculate CIFFT otherwise calculates CFFT);
- * <code>bitReverseFlag</code> Flag for selection of output order(Set bitReverseFlag to output in normal order otherwise output in bit reversed order);
- * <code>pTwiddle</code>points to array of twiddle coefficients; <code>pBitRevTable</code> points to the array of bit reversal table.
- * <code>twidCoefModifier</code> modifier for twiddle factor table which supports all FFT lengths with same table;
- * <code>pBitRevTable</code> modifier for bit reversal table which supports all FFT lengths with same table.
- * <code>onebyfftLen</code> value of 1/fftLen to calculate CIFFT;
- *
- * \par Fixed-Point Behavior
- * Care must be taken when using the fixed-point versions of the CFFT/CIFFT function.
- * Refer to the function specific documentation below for usage guidelines.
- */
-
-
-/**
- * @addtogroup Radix4_CFFT_CIFFT
- * @{
- */
-
-/**
- * @details
- * @brief Processing function for the floating-point Radix-4 CFFT/CIFFT.
- * @param[in] *S points to an instance of the floating-point Radix-4 CFFT/CIFFT structure.
- * @param[in, out] *pSrc points to the complex data buffer of size <code>2*fftLen</code>. Processing occurs in-place.
- * @return none.
- */
-
-void arm_cfft_radix4_f32(
- const arm_cfft_radix4_instance_f32 * S,
- float32_t * pSrc)
-{
-
- if(S->ifftFlag == 1u)
- {
- /* Complex IFFT radix-4 */
- arm_radix4_butterfly_inverse_f32(pSrc, S->fftLen, S->pTwiddle,
- S->twidCoefModifier, S->onebyfftLen);
- }
- else
- {
- /* Complex FFT radix-4 */
- arm_radix4_butterfly_f32(pSrc, S->fftLen, S->pTwiddle,
- S->twidCoefModifier);
- }
-
- if(S->bitReverseFlag == 1u)
- {
- /* Bit Reversal */
- arm_bitreversal_f32(pSrc, S->fftLen, S->bitRevFactor, S->pBitRevTable);
- }
-
-}
-
-
-/**
- * @} end of Radix4_CFFT_CIFFT group
- */
-
-
-/* ----------------------------------------------------------------------
-** Internal helper function used by the FFTs
-** ------------------------------------------------------------------- */
-
-/*
- * @brief Core function for the floating-point CFFT butterfly process.
- * @param[in, out] *pSrc points to the in-place buffer of floating-point data type.
- * @param[in] fftLen length of the FFT.
- * @param[in] *pCoef points to the twiddle coefficient buffer.
- * @param[in] twidCoefModifier twiddle coefficient modifier that supports different size FFTs with the same twiddle factor table.
- * @return none.
- */
-
-void arm_radix4_butterfly_f32(
- float32_t * pSrc,
- uint16_t fftLen,
- float32_t * pCoef,
- uint16_t twidCoefModifier)
-{
-
- float32_t co1, co2, co3, si1, si2, si3;
- uint32_t ia1, ia2, ia3;
- uint32_t i0, i1, i2, i3;
- uint32_t n1, n2, j, k;
-
-#ifndef ARM_MATH_CM0
-
- /* Run the below code for Cortex-M4 and Cortex-M3 */
-
- float32_t xaIn, yaIn, xbIn, ybIn, xcIn, ycIn, xdIn, ydIn;
- float32_t Xaplusc, Xbplusd, Yaplusc, Ybplusd, Xaminusc, Xbminusd, Yaminusc,
- Ybminusd;
- float32_t Xb12C_out, Yb12C_out, Xc12C_out, Yc12C_out, Xd12C_out, Yd12C_out;
- float32_t Xb12_out, Yb12_out, Xc12_out, Yc12_out, Xd12_out, Yd12_out;
- float32_t *ptr1;
-
- /* Initializations for the first stage */
- n2 = fftLen;
- n1 = n2;
-
- /* n2 = fftLen/4 */
- n2 >>= 2u;
- i0 = 0u;
- ia1 = 0u;
-
- j = n2;
-
- /* Calculation of first stage */
- do
- {
- /* index calculation for the input as, */
- /* pSrc[i0 + 0], pSrc[i0 + fftLen/4], pSrc[i0 + fftLen/2], pSrc[i0 + 3fftLen/4] */
- i1 = i0 + n2;
- i2 = i1 + n2;
- i3 = i2 + n2;
-
- xaIn = pSrc[(2u * i0)];
- yaIn = pSrc[(2u * i0) + 1u];
-
- xcIn = pSrc[(2u * i2)];
- ycIn = pSrc[(2u * i2) + 1u];
-
- xbIn = pSrc[(2u * i1)];
- ybIn = pSrc[(2u * i1) + 1u];
-
- xdIn = pSrc[(2u * i3)];
- ydIn = pSrc[(2u * i3) + 1u];
-
- /* xa + xc */
- Xaplusc = xaIn + xcIn;
- /* xb + xd */
- Xbplusd = xbIn + xdIn;
- /* ya + yc */
- Yaplusc = yaIn + ycIn;
- /* yb + yd */
- Ybplusd = ybIn + ydIn;
-
- /* index calculation for the coefficients */
- ia2 = ia1 + ia1;
- co2 = pCoef[ia2 * 2u];
- si2 = pCoef[(ia2 * 2u) + 1u];
-
- /* xa - xc */
- Xaminusc = xaIn - xcIn;
- /* xb - xd */
- Xbminusd = xbIn - xdIn;
- /* ya - yc */
- Yaminusc = yaIn - ycIn;
- /* yb + yd */
- Ybminusd = ybIn - ydIn;
-
- /* xa' = xa + xb + xc + xd */
- pSrc[(2u * i0)] = Xaplusc + Xbplusd;
- /* ya' = ya + yb + yc + yd */
- pSrc[(2u * i0) + 1u] = Yaplusc + Ybplusd;
-
- /* (xa - xc) + (yb - yd) */
- Xb12C_out = (Xaminusc + Ybminusd);
- /* (ya - yc) + (xb - xd) */
- Yb12C_out = (Yaminusc - Xbminusd);
- /* (xa + xc) - (xb + xd) */
- Xc12C_out = (Xaplusc - Xbplusd);
- /* (ya + yc) - (yb + yd) */
- Yc12C_out = (Yaplusc - Ybplusd);
- /* (xa - xc) - (yb - yd) */
- Xd12C_out = (Xaminusc - Ybminusd);
- /* (ya - yc) + (xb - xd) */
- Yd12C_out = (Xbminusd + Yaminusc);
-
- co1 = pCoef[ia1 * 2u];
- si1 = pCoef[(ia1 * 2u) + 1u];
-
- /* index calculation for the coefficients */
- ia3 = ia2 + ia1;
- co3 = pCoef[ia3 * 2u];
- si3 = pCoef[(ia3 * 2u) + 1u];
-
- Xb12_out = Xb12C_out * co1;
- Yb12_out = Yb12C_out * co1;
- Xc12_out = Xc12C_out * co2;
- Yc12_out = Yc12C_out * co2;
- Xd12_out = Xd12C_out * co3;
- Yd12_out = Yd12C_out * co3;
-
- /* xb' = (xa+yb-xc-yd)co1 + (ya-xb-yc+xd)(si1) */
- Xb12_out += Yb12C_out * si1;
- /* yb' = (ya-xb-yc+xd)co1 - (xa+yb-xc-yd)(si1) */
- Yb12_out -= Xb12C_out * si1;
- /* xc' = (xa-xb+xc-xd)co2 + (ya-yb+yc-yd)(si2) */
- Xc12_out += Yc12C_out * si2;
- /* yc' = (ya-yb+yc-yd)co2 - (xa-xb+xc-xd)(si2) */
- Yc12_out -= Xc12C_out * si2;
- /* xd' = (xa-yb-xc+yd)co3 + (ya+xb-yc-xd)(si3) */
- Xd12_out += Yd12C_out * si3;
- /* yd' = (ya+xb-yc-xd)co3 - (xa-yb-xc+yd)(si3) */
- Yd12_out -= Xd12C_out * si3;
-
-
- /* xc' = (xa-xb+xc-xd)co2 + (ya-yb+yc-yd)(si2) */
- pSrc[2u * i1] = Xc12_out;
-
- /* yc' = (ya-yb+yc-yd)co2 - (xa-xb+xc-xd)(si2) */
- pSrc[(2u * i1) + 1u] = Yc12_out;
-
- /* xb' = (xa+yb-xc-yd)co1 + (ya-xb-yc+xd)(si1) */
- pSrc[2u * i2] = Xb12_out;
-
- /* yb' = (ya-xb-yc+xd)co1 - (xa+yb-xc-yd)(si1) */
- pSrc[(2u * i2) + 1u] = Yb12_out;
-
- /* xd' = (xa-yb-xc+yd)co3 + (ya+xb-yc-xd)(si3) */
- pSrc[2u * i3] = Xd12_out;
-
- /* yd' = (ya+xb-yc-xd)co3 - (xa-yb-xc+yd)(si3) */
- pSrc[(2u * i3) + 1u] = Yd12_out;
-
- /* Twiddle coefficients index modifier */
- ia1 = ia1 + twidCoefModifier;
-
- /* Updating input index */
- i0 = i0 + 1u;
-
- }
- while(--j);
-
- twidCoefModifier <<= 2u;
-
- /* Calculation of second stage to excluding last stage */
- for (k = fftLen / 4; k > 4u; k >>= 2u)
- {
- /* Initializations for the first stage */
- n1 = n2;
- n2 >>= 2u;
- ia1 = 0u;
-
- /* Calculation of first stage */
- for (j = 0u; j <= (n2 - 1u); j++)
- {
- /* index calculation for the coefficients */
- ia2 = ia1 + ia1;
- ia3 = ia2 + ia1;
- co1 = pCoef[ia1 * 2u];
- si1 = pCoef[(ia1 * 2u) + 1u];
- co2 = pCoef[ia2 * 2u];
- si2 = pCoef[(ia2 * 2u) + 1u];
- co3 = pCoef[ia3 * 2u];
- si3 = pCoef[(ia3 * 2u) + 1u];
-
- /* Twiddle coefficients index modifier */
- ia1 = ia1 + twidCoefModifier;
-
- for (i0 = j; i0 < fftLen; i0 += n1)
- {
- /* index calculation for the input as, */
- /* pSrc[i0 + 0], pSrc[i0 + fftLen/4], pSrc[i0 + fftLen/2], pSrc[i0 + 3fftLen/4] */
- i1 = i0 + n2;
- i2 = i1 + n2;
- i3 = i2 + n2;
-
- xaIn = pSrc[(2u * i0)];
- yaIn = pSrc[(2u * i0) + 1u];
-
- xbIn = pSrc[(2u * i1)];
- ybIn = pSrc[(2u * i1) + 1u];
-
- xcIn = pSrc[(2u * i2)];
- ycIn = pSrc[(2u * i2) + 1u];
-
- xdIn = pSrc[(2u * i3)];
- ydIn = pSrc[(2u * i3) + 1u];
-
- /* xa - xc */
- Xaminusc = xaIn - xcIn;
- /* (xb - xd) */
- Xbminusd = xbIn - xdIn;
- /* ya - yc */
- Yaminusc = yaIn - ycIn;
- /* (yb - yd) */
- Ybminusd = ybIn - ydIn;
-
- /* xa + xc */
- Xaplusc = xaIn + xcIn;
- /* xb + xd */
- Xbplusd = xbIn + xdIn;
- /* ya + yc */
- Yaplusc = yaIn + ycIn;
- /* yb + yd */
- Ybplusd = ybIn + ydIn;
-
- /* (xa - xc) + (yb - yd) */
- Xb12C_out = (Xaminusc + Ybminusd);
- /* (ya - yc) - (xb - xd) */
- Yb12C_out = (Yaminusc - Xbminusd);
- /* xa + xc -(xb + xd) */
- Xc12C_out = (Xaplusc - Xbplusd);
- /* (ya + yc) - (yb + yd) */
- Yc12C_out = (Yaplusc - Ybplusd);
- /* (xa - xc) - (yb - yd) */
- Xd12C_out = (Xaminusc - Ybminusd);
- /* (ya - yc) + (xb - xd) */
- Yd12C_out = (Xbminusd + Yaminusc);
-
- pSrc[(2u * i0)] = Xaplusc + Xbplusd;
- pSrc[(2u * i0) + 1u] = Yaplusc + Ybplusd;
-
- Xb12_out = Xb12C_out * co1;
- Yb12_out = Yb12C_out * co1;
- Xc12_out = Xc12C_out * co2;
- Yc12_out = Yc12C_out * co2;
- Xd12_out = Xd12C_out * co3;
- Yd12_out = Yd12C_out * co3;
-
- /* xb' = (xa+yb-xc-yd)co1 + (ya-xb-yc+xd)(si1) */
- Xb12_out += Yb12C_out * si1;
- /* yb' = (ya-xb-yc+xd)co1 - (xa+yb-xc-yd)(si1) */
- Yb12_out -= Xb12C_out * si1;
- /* xc' = (xa-xb+xc-xd)co2 + (ya-yb+yc-yd)(si2) */
- Xc12_out += Yc12C_out * si2;
- /* yc' = (ya-yb+yc-yd)co2 - (xa-xb+xc-xd)(si2) */
- Yc12_out -= Xc12C_out * si2;
- /* xd' = (xa-yb-xc+yd)co3 + (ya+xb-yc-xd)(si3) */
- Xd12_out += Yd12C_out * si3;
- /* yd' = (ya+xb-yc-xd)co3 - (xa-yb-xc+yd)(si3) */
- Yd12_out -= Xd12C_out * si3;
-
- /* xc' = (xa-xb+xc-xd)co2 + (ya-yb+yc-yd)(si2) */
- pSrc[2u * i1] = Xc12_out;
-
- /* yc' = (ya-yb+yc-yd)co2 - (xa-xb+xc-xd)(si2) */
- pSrc[(2u * i1) + 1u] = Yc12_out;
-
- /* xb' = (xa+yb-xc-yd)co1 + (ya-xb-yc+xd)(si1) */
- pSrc[2u * i2] = Xb12_out;
-
- /* yb' = (ya-xb-yc+xd)co1 - (xa+yb-xc-yd)(si1) */
- pSrc[(2u * i2) + 1u] = Yb12_out;
-
- /* xd' = (xa-yb-xc+yd)co3 + (ya+xb-yc-xd)(si3) */
- pSrc[2u * i3] = Xd12_out;
-
- /* yd' = (ya+xb-yc-xd)co3 - (xa-yb-xc+yd)(si3) */
- pSrc[(2u * i3) + 1u] = Yd12_out;
-
- }
- }
- twidCoefModifier <<= 2u;
- }
-
- j = fftLen >> 2;
- ptr1 = &pSrc[0];
-
- /* Calculations of last stage */
- do
- {
-
- xaIn = ptr1[0];
- xcIn = ptr1[4];
- yaIn = ptr1[1];
- ycIn = ptr1[5];
-
- /* xa + xc */
- Xaplusc = xaIn + xcIn;
-
- xbIn = ptr1[2];
-
- /* xa - xc */
- Xaminusc = xaIn - xcIn;
-
- xdIn = ptr1[6];
-
- /* ya + yc */
- Yaplusc = yaIn + ycIn;
-
- ybIn = ptr1[3];
-
- /* ya - yc */
- Yaminusc = yaIn - ycIn;
-
- ydIn = ptr1[7];
-
- /* xb + xd */
- Xbplusd = xbIn + xdIn;
-
- /* yb + yd */
- Ybplusd = ybIn + ydIn;
-
- /* xa' = xa + xb + xc + xd */
- ptr1[0] = (Xaplusc + Xbplusd);
-
- /* (xb-xd) */
- Xbminusd = xbIn - xdIn;
-
- /* ya' = ya + yb + yc + yd */
- ptr1[1] = (Yaplusc + Ybplusd);
-
- /* (yb-yd) */
- Ybminusd = ybIn - ydIn;
-
- /* xc' = (xa-xb+xc-xd) */
- ptr1[2] = (Xaplusc - Xbplusd);
- /* yc' = (ya-yb+yc-yd) */
- ptr1[3] = (Yaplusc - Ybplusd);
- /* xb' = (xa+yb-xc-yd) */
- ptr1[4] = (Xaminusc + Ybminusd);
- /* yb' = (ya-xb-yc+xd) */
- ptr1[5] = (Yaminusc - Xbminusd);
- /* xd' = (xa-yb-xc+yd)) */
- ptr1[6] = (Xaminusc - Ybminusd);
- /* yd' = (ya+xb-yc-xd) */
- ptr1[7] = (Xbminusd + Yaminusc);
-
- /* increment pointer by 8 */
- ptr1 = ptr1 + 8u;
-
- } while(--j);
-
-#else
-
- float32_t t1, t2, r1, r2, s1, s2;
-
- /* Run the below code for Cortex-M0 */
-
- /* Initializations for the fft calculation */
- n2 = fftLen;
- n1 = n2;
- for (k = fftLen; k > 1u; k >>= 2u)
- {
- /* Initializations for the fft calculation */
- n1 = n2;
- n2 >>= 2u;
- ia1 = 0u;
-
- /* FFT Calculation */
- for (j = 0u; j <= (n2 - 1u); j++)
- {
- /* index calculation for the coefficients */
- ia2 = ia1 + ia1;
- ia3 = ia2 + ia1;
- co1 = pCoef[ia1 * 2u];
- si1 = pCoef[(ia1 * 2u) + 1u];
- co2 = pCoef[ia2 * 2u];
- si2 = pCoef[(ia2 * 2u) + 1u];
- co3 = pCoef[ia3 * 2u];
- si3 = pCoef[(ia3 * 2u) + 1u];
-
- /* Twiddle coefficients index modifier */
- ia1 = ia1 + twidCoefModifier;
-
- for (i0 = j; i0 < fftLen; i0 += n1)
- {
- /* index calculation for the input as, */
- /* pSrc[i0 + 0], pSrc[i0 + fftLen/4], pSrc[i0 + fftLen/2], pSrc[i0 + 3fftLen/4] */
- i1 = i0 + n2;
- i2 = i1 + n2;
- i3 = i2 + n2;
-
- /* xa + xc */
- r1 = pSrc[(2u * i0)] + pSrc[(2u * i2)];
-
- /* xa - xc */
- r2 = pSrc[(2u * i0)] - pSrc[(2u * i2)];
-
- /* ya + yc */
- s1 = pSrc[(2u * i0) + 1u] + pSrc[(2u * i2) + 1u];
-
- /* ya - yc */
- s2 = pSrc[(2u * i0) + 1u] - pSrc[(2u * i2) + 1u];
-
- /* xb + xd */
- t1 = pSrc[2u * i1] + pSrc[2u * i3];
-
- /* xa' = xa + xb + xc + xd */
- pSrc[2u * i0] = r1 + t1;
-
- /* xa + xc -(xb + xd) */
- r1 = r1 - t1;
-
- /* yb + yd */
- t2 = pSrc[(2u * i1) + 1u] + pSrc[(2u * i3) + 1u];
-
- /* ya' = ya + yb + yc + yd */
- pSrc[(2u * i0) + 1u] = s1 + t2;
-
- /* (ya + yc) - (yb + yd) */
- s1 = s1 - t2;
-
- /* (yb - yd) */
- t1 = pSrc[(2u * i1) + 1u] - pSrc[(2u * i3) + 1u];
-
- /* (xb - xd) */
- t2 = pSrc[2u * i1] - pSrc[2u * i3];
-
- /* xc' = (xa-xb+xc-xd)co2 + (ya-yb+yc-yd)(si2) */
- pSrc[2u * i1] = (r1 * co2) + (s1 * si2);
-
- /* yc' = (ya-yb+yc-yd)co2 - (xa-xb+xc-xd)(si2) */
- pSrc[(2u * i1) + 1u] = (s1 * co2) - (r1 * si2);
-
- /* (xa - xc) + (yb - yd) */
- r1 = r2 + t1;
-
- /* (xa - xc) - (yb - yd) */
- r2 = r2 - t1;
-
- /* (ya - yc) - (xb - xd) */
- s1 = s2 - t2;
-
- /* (ya - yc) + (xb - xd) */
- s2 = s2 + t2;
-
- /* xb' = (xa+yb-xc-yd)co1 + (ya-xb-yc+xd)(si1) */
- pSrc[2u * i2] = (r1 * co1) + (s1 * si1);
-
- /* yb' = (ya-xb-yc+xd)co1 - (xa+yb-xc-yd)(si1) */
- pSrc[(2u * i2) + 1u] = (s1 * co1) - (r1 * si1);
-
- /* xd' = (xa-yb-xc+yd)co3 + (ya+xb-yc-xd)(si3) */
- pSrc[2u * i3] = (r2 * co3) + (s2 * si3);
-
- /* yd' = (ya+xb-yc-xd)co3 - (xa-yb-xc+yd)(si3) */
- pSrc[(2u * i3) + 1u] = (s2 * co3) - (r2 * si3);
- }
- }
- twidCoefModifier <<= 2u;
- }
-
-#endif /* #ifndef ARM_MATH_CM0 */
-
-}
-
-/*
- * @brief Core function for the floating-point CIFFT butterfly process.
- * @param[in, out] *pSrc points to the in-place buffer of floating-point data type.
- * @param[in] fftLen length of the FFT.
- * @param[in] *pCoef points to twiddle coefficient buffer.
- * @param[in] twidCoefModifier twiddle coefficient modifier that supports different size FFTs with the same twiddle factor table.
- * @param[in] onebyfftLen value of 1/fftLen.
- * @return none.
- */
-
-void arm_radix4_butterfly_inverse_f32(
- float32_t * pSrc,
- uint16_t fftLen,
- float32_t * pCoef,
- uint16_t twidCoefModifier,
- float32_t onebyfftLen)
-{
- float32_t co1, co2, co3, si1, si2, si3;
- uint32_t ia1, ia2, ia3;
- uint32_t i0, i1, i2, i3;
- uint32_t n1, n2, j, k;
-
-#ifndef ARM_MATH_CM0
-
- float32_t xaIn, yaIn, xbIn, ybIn, xcIn, ycIn, xdIn, ydIn;
- float32_t Xaplusc, Xbplusd, Yaplusc, Ybplusd, Xaminusc, Xbminusd, Yaminusc,
- Ybminusd;
- float32_t Xb12C_out, Yb12C_out, Xc12C_out, Yc12C_out, Xd12C_out, Yd12C_out;
- float32_t Xb12_out, Yb12_out, Xc12_out, Yc12_out, Xd12_out, Yd12_out;
- float32_t *ptr1;
-
-
- /* Initializations for the first stage */
- n2 = fftLen;
- n1 = n2;
-
- /* n2 = fftLen/4 */
- n2 >>= 2u;
- i0 = 0u;
- ia1 = 0u;
-
- j = n2;
-
- /* Calculation of first stage */
- do
- {
- /* index calculation for the input as, */
- /* pSrc[i0 + 0], pSrc[i0 + fftLen/4], pSrc[i0 + fftLen/2], pSrc[i0 + 3fftLen/4] */
- i1 = i0 + n2;
- i2 = i1 + n2;
- i3 = i2 + n2;
-
- /* Butterfly implementation */
- xaIn = pSrc[(2u * i0)];
- yaIn = pSrc[(2u * i0) + 1u];
-
- xcIn = pSrc[(2u * i2)];
- ycIn = pSrc[(2u * i2) + 1u];
-
- xbIn = pSrc[(2u * i1)];
- ybIn = pSrc[(2u * i1) + 1u];
-
- xdIn = pSrc[(2u * i3)];
- ydIn = pSrc[(2u * i3) + 1u];
-
- /* xa + xc */
- Xaplusc = xaIn + xcIn;
- /* xb + xd */
- Xbplusd = xbIn + xdIn;
- /* ya + yc */
- Yaplusc = yaIn + ycIn;
- /* yb + yd */
- Ybplusd = ybIn + ydIn;
-
- /* index calculation for the coefficients */
- ia2 = ia1 + ia1;
- co2 = pCoef[ia2 * 2u];
- si2 = pCoef[(ia2 * 2u) + 1u];
-
- /* xa - xc */
- Xaminusc = xaIn - xcIn;
- /* xb - xd */
- Xbminusd = xbIn - xdIn;
- /* ya - yc */
- Yaminusc = yaIn - ycIn;
- /* yb - yd */
- Ybminusd = ybIn - ydIn;
-
- /* xa' = xa + xb + xc + xd */
- pSrc[(2u * i0)] = Xaplusc + Xbplusd;
-
- /* ya' = ya + yb + yc + yd */
- pSrc[(2u * i0) + 1u] = Yaplusc + Ybplusd;
-
- /* (xa - xc) - (yb - yd) */
- Xb12C_out = (Xaminusc - Ybminusd);
- /* (ya - yc) + (xb - xd) */
- Yb12C_out = (Yaminusc + Xbminusd);
- /* (xa + xc) - (xb + xd) */
- Xc12C_out = (Xaplusc - Xbplusd);
- /* (ya + yc) - (yb + yd) */
- Yc12C_out = (Yaplusc - Ybplusd);
- /* (xa - xc) + (yb - yd) */
- Xd12C_out = (Xaminusc + Ybminusd);
- /* (ya - yc) - (xb - xd) */
- Yd12C_out = (Yaminusc - Xbminusd);
-
- co1 = pCoef[ia1 * 2u];
- si1 = pCoef[(ia1 * 2u) + 1u];
-
- /* index calculation for the coefficients */
- ia3 = ia2 + ia1;
- co3 = pCoef[ia3 * 2u];
- si3 = pCoef[(ia3 * 2u) + 1u];
-
- Xb12_out = Xb12C_out * co1;
- Yb12_out = Yb12C_out * co1;
- Xc12_out = Xc12C_out * co2;
- Yc12_out = Yc12C_out * co2;
- Xd12_out = Xd12C_out * co3;
- Yd12_out = Yd12C_out * co3;
-
- /* xb' = (xa+yb-xc-yd)co1 - (ya-xb-yc+xd)(si1) */
- Xb12_out -= Yb12C_out * si1;
- /* yb' = (ya-xb-yc+xd)co1 + (xa+yb-xc-yd)(si1) */
- Yb12_out += Xb12C_out * si1;
- /* xc' = (xa-xb+xc-xd)co2 - (ya-yb+yc-yd)(si2) */
- Xc12_out -= Yc12C_out * si2;
- /* yc' = (ya-yb+yc-yd)co2 + (xa-xb+xc-xd)(si2) */
- Yc12_out += Xc12C_out * si2;
- /* xd' = (xa-yb-xc+yd)co3 - (ya+xb-yc-xd)(si3) */
- Xd12_out -= Yd12C_out * si3;
- /* yd' = (ya+xb-yc-xd)co3 + (xa-yb-xc+yd)(si3) */
- Yd12_out += Xd12C_out * si3;
-
- /* xc' = (xa-xb+xc-xd)co2 - (ya-yb+yc-yd)(si2) */
- pSrc[2u * i1] = Xc12_out;
-
- /* yc' = (ya-yb+yc-yd)co2 + (xa-xb+xc-xd)(si2) */
- pSrc[(2u * i1) + 1u] = Yc12_out;
-
- /* xb' = (xa+yb-xc-yd)co1 - (ya-xb-yc+xd)(si1) */
- pSrc[2u * i2] = Xb12_out;
-
- /* yb' = (ya-xb-yc+xd)co1 + (xa+yb-xc-yd)(si1) */
- pSrc[(2u * i2) + 1u] = Yb12_out;
-
- /* xd' = (xa-yb-xc+yd)co3 - (ya+xb-yc-xd)(si3) */
- pSrc[2u * i3] = Xd12_out;
-
- /* yd' = (ya+xb-yc-xd)co3 + (xa-yb-xc+yd)(si3) */
- pSrc[(2u * i3) + 1u] = Yd12_out;
-
- /* Twiddle coefficients index modifier */
- ia1 = ia1 + twidCoefModifier;
-
- /* Updating input index */
- i0 = i0 + 1u;
-
- } while(--j);
-
- twidCoefModifier <<= 2u;
-
- /* Calculation of second stage to excluding last stage */
- for (k = fftLen / 4; k > 4u; k >>= 2u)
- {
- /* Initializations for the first stage */
- n1 = n2;
- n2 >>= 2u;
- ia1 = 0u;
-
- /* Calculation of first stage */
- for (j = 0u; j <= (n2 - 1u); j++)
- {
- /* index calculation for the coefficients */
- ia2 = ia1 + ia1;
- ia3 = ia2 + ia1;
- co1 = pCoef[ia1 * 2u];
- si1 = pCoef[(ia1 * 2u) + 1u];
- co2 = pCoef[ia2 * 2u];
- si2 = pCoef[(ia2 * 2u) + 1u];
- co3 = pCoef[ia3 * 2u];
- si3 = pCoef[(ia3 * 2u) + 1u];
-
- /* Twiddle coefficients index modifier */
- ia1 = ia1 + twidCoefModifier;
-
- for (i0 = j; i0 < fftLen; i0 += n1)
- {
- /* index calculation for the input as, */
- /* pSrc[i0 + 0], pSrc[i0 + fftLen/4], pSrc[i0 + fftLen/2], pSrc[i0 + 3fftLen/4] */
- i1 = i0 + n2;
- i2 = i1 + n2;
- i3 = i2 + n2;
-
- xaIn = pSrc[(2u * i0)];
- yaIn = pSrc[(2u * i0) + 1u];
-
- xbIn = pSrc[(2u * i1)];
- ybIn = pSrc[(2u * i1) + 1u];
-
- xcIn = pSrc[(2u * i2)];
- ycIn = pSrc[(2u * i2) + 1u];
-
- xdIn = pSrc[(2u * i3)];
- ydIn = pSrc[(2u * i3) + 1u];
-
- /* xa - xc */
- Xaminusc = xaIn - xcIn;
- /* (xb - xd) */
- Xbminusd = xbIn - xdIn;
- /* ya - yc */
- Yaminusc = yaIn - ycIn;
- /* (yb - yd) */
- Ybminusd = ybIn - ydIn;
-
- /* xa + xc */
- Xaplusc = xaIn + xcIn;
- /* xb + xd */
- Xbplusd = xbIn + xdIn;
- /* ya + yc */
- Yaplusc = yaIn + ycIn;
- /* yb + yd */
- Ybplusd = ybIn + ydIn;
-
- /* (xa - xc) - (yb - yd) */
- Xb12C_out = (Xaminusc - Ybminusd);
- /* (ya - yc) + (xb - xd) */
- Yb12C_out = (Yaminusc + Xbminusd);
- /* xa + xc -(xb + xd) */
- Xc12C_out = (Xaplusc - Xbplusd);
- /* (ya + yc) - (yb + yd) */
- Yc12C_out = (Yaplusc - Ybplusd);
- /* (xa - xc) + (yb - yd) */
- Xd12C_out = (Xaminusc + Ybminusd);
- /* (ya - yc) - (xb - xd) */
- Yd12C_out = (Yaminusc - Xbminusd);
-
- pSrc[(2u * i0)] = Xaplusc + Xbplusd;
- pSrc[(2u * i0) + 1u] = Yaplusc + Ybplusd;
-
- Xb12_out = Xb12C_out * co1;
- Yb12_out = Yb12C_out * co1;
- Xc12_out = Xc12C_out * co2;
- Yc12_out = Yc12C_out * co2;
- Xd12_out = Xd12C_out * co3;
- Yd12_out = Yd12C_out * co3;
-
- /* xb' = (xa+yb-xc-yd)co1 - (ya-xb-yc+xd)(si1) */
- Xb12_out -= Yb12C_out * si1;
- /* yb' = (ya-xb-yc+xd)co1 + (xa+yb-xc-yd)(si1) */
- Yb12_out += Xb12C_out * si1;
- /* xc' = (xa-xb+xc-xd)co2 - (ya-yb+yc-yd)(si2) */
- Xc12_out -= Yc12C_out * si2;
- /* yc' = (ya-yb+yc-yd)co2 + (xa-xb+xc-xd)(si2) */
- Yc12_out += Xc12C_out * si2;
- /* xd' = (xa-yb-xc+yd)co3 - (ya+xb-yc-xd)(si3) */
- Xd12_out -= Yd12C_out * si3;
- /* yd' = (ya+xb-yc-xd)co3 + (xa-yb-xc+yd)(si3) */
- Yd12_out += Xd12C_out * si3;
-
- /* xc' = (xa-xb+xc-xd)co2 - (ya-yb+yc-yd)(si2) */
- pSrc[2u * i1] = Xc12_out;
-
- /* yc' = (ya-yb+yc-yd)co2 + (xa-xb+xc-xd)(si2) */
- pSrc[(2u * i1) + 1u] = Yc12_out;
-
- /* xb' = (xa+yb-xc-yd)co1 - (ya-xb-yc+xd)(si1) */
- pSrc[2u * i2] = Xb12_out;
-
- /* yb' = (ya-xb-yc+xd)co1 + (xa+yb-xc-yd)(si1) */
- pSrc[(2u * i2) + 1u] = Yb12_out;
-
- /* xd' = (xa-yb-xc+yd)co3 - (ya+xb-yc-xd)(si3) */
- pSrc[2u * i3] = Xd12_out;
-
- /* yd' = (ya+xb-yc-xd)co3 + (xa-yb-xc+yd)(si3) */
- pSrc[(2u * i3) + 1u] = Yd12_out;
-
- }
- }
- twidCoefModifier <<= 2u;
- }
- /* Initializations of last stage */
-
- j = fftLen >> 2;
- ptr1 = &pSrc[0];
-
- /* Calculations of last stage */
- do
- {
-
- xaIn = ptr1[0];
- xcIn = ptr1[4];
- yaIn = ptr1[1];
- ycIn = ptr1[5];
-
- /* Butterfly implementation */
- /* xa + xc */
- Xaplusc = xaIn + xcIn;
-
- xbIn = ptr1[2];
-
- /* xa - xc */
- Xaminusc = xaIn - xcIn;
-
- xdIn = ptr1[6];
-
- /* ya + yc */
- Yaplusc = yaIn + ycIn;
-
- ybIn = ptr1[3];
-
- /* ya - yc */
- Yaminusc = yaIn - ycIn;
-
- ydIn = ptr1[7];
-
- /* xc + xd */
- Xbplusd = xbIn + xdIn;
-
- /* yb + yd */
- Ybplusd = ybIn + ydIn;
-
- /* xa' = xa + xb + xc + xd */
- ptr1[0] = (Xaplusc + Xbplusd) * onebyfftLen;
-
- /* (xb-xd) */
- Xbminusd = xbIn - xdIn;
-
- /* ya' = ya + yb + yc + yd */
- ptr1[1] = (Yaplusc + Ybplusd) * onebyfftLen;
-
- /* (yb-yd) */
- Ybminusd = ybIn - ydIn;
-
- /* xc' = (xa-xb+xc-xd) * onebyfftLen */
- ptr1[2] = (Xaplusc - Xbplusd) * onebyfftLen;
-
- /* yc' = (ya-yb+yc-yd) * onebyfftLen */
- ptr1[3] = (Yaplusc - Ybplusd) * onebyfftLen;
-
- /* xb' = (xa-yb-xc+yd) * onebyfftLen */
- ptr1[4] = (Xaminusc - Ybminusd) * onebyfftLen;
-
- /* yb' = (ya+xb-yc-xd) * onebyfftLen */
- ptr1[5] = (Yaminusc + Xbminusd) * onebyfftLen;
-
- /* xd' = (xa-yb-xc+yd) * onebyfftLen */
- ptr1[6] = (Xaminusc + Ybminusd) * onebyfftLen;
-
- /* yd' = (ya-xb-yc+xd) * onebyfftLen */
- ptr1[7] = (Yaminusc - Xbminusd) * onebyfftLen;
-
- /* increment source pointer by 8 for next calculations */
- ptr1 = ptr1 + 8u;
-
- } while(--j);
-
-#else
-
- float32_t t1, t2, r1, r2, s1, s2;
-
- /* Run the below code for Cortex-M0 */
-
- /* Initializations for the first stage */
- n2 = fftLen;
- n1 = n2;
-
- /* Calculation of first stage */
- for (k = fftLen; k > 4u; k >>= 2u)
- {
- /* Initializations for the first stage */
- n1 = n2;
- n2 >>= 2u;
- ia1 = 0u;
-
- /* Calculation of first stage */
- for (j = 0u; j <= (n2 - 1u); j++)
- {
- /* index calculation for the coefficients */
- ia2 = ia1 + ia1;
- ia3 = ia2 + ia1;
- co1 = pCoef[ia1 * 2u];
- si1 = pCoef[(ia1 * 2u) + 1u];
- co2 = pCoef[ia2 * 2u];
- si2 = pCoef[(ia2 * 2u) + 1u];
- co3 = pCoef[ia3 * 2u];
- si3 = pCoef[(ia3 * 2u) + 1u];
-
- /* Twiddle coefficients index modifier */
- ia1 = ia1 + twidCoefModifier;
-
- for (i0 = j; i0 < fftLen; i0 += n1)
- {
- /* index calculation for the input as, */
- /* pSrc[i0 + 0], pSrc[i0 + fftLen/4], pSrc[i0 + fftLen/2], pSrc[i0 + 3fftLen/4] */
- i1 = i0 + n2;
- i2 = i1 + n2;
- i3 = i2 + n2;
-
- /* xa + xc */
- r1 = pSrc[(2u * i0)] + pSrc[(2u * i2)];
-
- /* xa - xc */
- r2 = pSrc[(2u * i0)] - pSrc[(2u * i2)];
-
- /* ya + yc */
- s1 = pSrc[(2u * i0) + 1u] + pSrc[(2u * i2) + 1u];
-
- /* ya - yc */
- s2 = pSrc[(2u * i0) + 1u] - pSrc[(2u * i2) + 1u];
-
- /* xb + xd */
- t1 = pSrc[2u * i1] + pSrc[2u * i3];
-
- /* xa' = xa + xb + xc + xd */
- pSrc[2u * i0] = r1 + t1;
-
- /* xa + xc -(xb + xd) */
- r1 = r1 - t1;
-
- /* yb + yd */
- t2 = pSrc[(2u * i1) + 1u] + pSrc[(2u * i3) + 1u];
-
- /* ya' = ya + yb + yc + yd */
- pSrc[(2u * i0) + 1u] = s1 + t2;
-
- /* (ya + yc) - (yb + yd) */
- s1 = s1 - t2;
-
- /* (yb - yd) */
- t1 = pSrc[(2u * i1) + 1u] - pSrc[(2u * i3) + 1u];
-
- /* (xb - xd) */
- t2 = pSrc[2u * i1] - pSrc[2u * i3];
-
- /* xc' = (xa-xb+xc-xd)co2 - (ya-yb+yc-yd)(si2) */
- pSrc[2u * i1] = (r1 * co2) - (s1 * si2);
-
- /* yc' = (ya-yb+yc-yd)co2 + (xa-xb+xc-xd)(si2) */
- pSrc[(2u * i1) + 1u] = (s1 * co2) + (r1 * si2);
-
- /* (xa - xc) - (yb - yd) */
- r1 = r2 - t1;
-
- /* (xa - xc) + (yb - yd) */
- r2 = r2 + t1;
-
- /* (ya - yc) + (xb - xd) */
- s1 = s2 + t2;
-
- /* (ya - yc) - (xb - xd) */
- s2 = s2 - t2;
-
- /* xb' = (xa+yb-xc-yd)co1 - (ya-xb-yc+xd)(si1) */
- pSrc[2u * i2] = (r1 * co1) - (s1 * si1);
-
- /* yb' = (ya-xb-yc+xd)co1 + (xa+yb-xc-yd)(si1) */
- pSrc[(2u * i2) + 1u] = (s1 * co1) + (r1 * si1);
-
- /* xd' = (xa-yb-xc+yd)co3 - (ya+xb-yc-xd)(si3) */
- pSrc[2u * i3] = (r2 * co3) - (s2 * si3);
-
- /* yd' = (ya+xb-yc-xd)co3 + (xa-yb-xc+yd)(si3) */
- pSrc[(2u * i3) + 1u] = (s2 * co3) + (r2 * si3);
- }
- }
- twidCoefModifier <<= 2u;
- }
- /* Initializations of last stage */
- n1 = n2;
- n2 >>= 2u;
-
- /* Calculations of last stage */
- for (i0 = 0u; i0 <= (fftLen - n1); i0 += n1)
- {
- /* index calculation for the input as, */
- /* pSrc[i0 + 0], pSrc[i0 + fftLen/4], pSrc[i0 + fftLen/2], pSrc[i0 + 3fftLen/4] */
- i1 = i0 + n2;
- i2 = i1 + n2;
- i3 = i2 + n2;
-
- /* Butterfly implementation */
- /* xa + xc */
- r1 = pSrc[2u * i0] + pSrc[2u * i2];
-
- /* xa - xc */
- r2 = pSrc[2u * i0] - pSrc[2u * i2];
-
- /* ya + yc */
- s1 = pSrc[(2u * i0) + 1u] + pSrc[(2u * i2) + 1u];
-
- /* ya - yc */
- s2 = pSrc[(2u * i0) + 1u] - pSrc[(2u * i2) + 1u];
-
- /* xc + xd */
- t1 = pSrc[2u * i1] + pSrc[2u * i3];
-
- /* xa' = xa + xb + xc + xd */
- pSrc[2u * i0] = (r1 + t1) * onebyfftLen;
-
- /* (xa + xb) - (xc + xd) */
- r1 = r1 - t1;
-
- /* yb + yd */
- t2 = pSrc[(2u * i1) + 1u] + pSrc[(2u * i3) + 1u];
-
- /* ya' = ya + yb + yc + yd */
- pSrc[(2u * i0) + 1u] = (s1 + t2) * onebyfftLen;
-
- /* (ya + yc) - (yb + yd) */
- s1 = s1 - t2;
-
- /* (yb-yd) */
- t1 = pSrc[(2u * i1) + 1u] - pSrc[(2u * i3) + 1u];
-
- /* (xb-xd) */
- t2 = pSrc[2u * i1] - pSrc[2u * i3];
-
- /* xc' = (xa-xb+xc-xd)co2 - (ya-yb+yc-yd)(si2) */
- pSrc[2u * i1] = r1 * onebyfftLen;
-
- /* yc' = (ya-yb+yc-yd)co2 + (xa-xb+xc-xd)(si2) */
- pSrc[(2u * i1) + 1u] = s1 * onebyfftLen;
-
-
- /* (xa - xc) - (yb-yd) */
- r1 = r2 - t1;
-
- /* (xa - xc) + (yb-yd) */
- r2 = r2 + t1;
-
- /* (ya - yc) + (xb-xd) */
- s1 = s2 + t2;
-
- /* (ya - yc) - (xb-xd) */
- s2 = s2 - t2;
-
- /* xb' = (xa+yb-xc-yd)co1 - (ya-xb-yc+xd)(si1) */
- pSrc[2u * i2] = r1 * onebyfftLen;
-
- /* yb' = (ya-xb-yc+xd)co1 + (xa+yb-xc-yd)(si1) */
- pSrc[(2u * i2) + 1u] = s1 * onebyfftLen;
-
- /* xd' = (xa-yb-xc+yd)co3 - (ya+xb-yc-xd)(si3) */
- pSrc[2u * i3] = r2 * onebyfftLen;
-
- /* yd' = (ya+xb-yc-xd)co3 + (xa-yb-xc+yd)(si3) */
- pSrc[(2u * i3) + 1u] = s2 * onebyfftLen;
- }
-
-#endif /* #ifndef ARM_MATH_CM0 */
-
-}
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