diff options
Diffstat (limited to 'src/modules/mathlib/CMSIS/DSP_Lib/Source/TransformFunctions/arm_cfft_radix4_q31.c')
| -rw-r--r-- | src/modules/mathlib/CMSIS/DSP_Lib/Source/TransformFunctions/arm_cfft_radix4_q31.c | 891 |
1 files changed, 0 insertions, 891 deletions
diff --git a/src/modules/mathlib/CMSIS/DSP_Lib/Source/TransformFunctions/arm_cfft_radix4_q31.c b/src/modules/mathlib/CMSIS/DSP_Lib/Source/TransformFunctions/arm_cfft_radix4_q31.c deleted file mode 100644 index 3a5c523df..000000000 --- a/src/modules/mathlib/CMSIS/DSP_Lib/Source/TransformFunctions/arm_cfft_radix4_q31.c +++ /dev/null @@ -1,891 +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_q31.c
-*
-* Description: This file has function definition of Radix-4 FFT & IFFT function and
-* In-place bit reversal using bit reversal table
-*
-* 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
- */
-
-/**
- * @addtogroup Radix4_CFFT_CIFFT
- * @{
- */
-
-/**
- * @details
- * @brief Processing function for the Q31 CFFT/CIFFT.
- * @param[in] *S points to an instance of the Q31 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.
- *
- * \par Input and output formats:
- * \par
- * Internally input is downscaled by 2 for every stage to avoid saturations inside CFFT/CIFFT process.
- * Hence the output format is different for different FFT sizes.
- * The input and output formats for different FFT sizes and number of bits to upscale are mentioned in the tables below for CFFT and CIFFT:
- * \par
- * \image html CFFTQ31.gif "Input and Output Formats for Q31 CFFT"
- * \image html CIFFTQ31.gif "Input and Output Formats for Q31 CIFFT"
- *
- */
-
-void arm_cfft_radix4_q31(
- const arm_cfft_radix4_instance_q31 * S,
- q31_t * pSrc)
-{
- if(S->ifftFlag == 1u)
- {
- /* Complex IFFT radix-4 */
- arm_radix4_butterfly_inverse_q31(pSrc, S->fftLen, S->pTwiddle,
- S->twidCoefModifier);
- }
- else
- {
- /* Complex FFT radix-4 */
- arm_radix4_butterfly_q31(pSrc, S->fftLen, S->pTwiddle,
- S->twidCoefModifier);
- }
-
-
- if(S->bitReverseFlag == 1u)
- {
- /* Bit Reversal */
- arm_bitreversal_q31(pSrc, S->fftLen, S->bitRevFactor, S->pBitRevTable);
- }
-
-}
-
-/**
- * @} end of Radix4_CFFT_CIFFT group
- */
-
-/*
-* Radix-4 FFT algorithm used is :
-*
-* Input real and imaginary data:
-* 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
-*
-*
-* Output real and imaginary data:
-* x(4r) = xa'+ j * ya'
-* x(4r+1) = xb'+ j * yb'
-* x(4r+2) = xc'+ j * yc'
-* x(4r+3) = xd'+ j * yd'
-*
-*
-* Twiddle factors for radix-4 FFT:
-* Wn = co1 + j * (- si1)
-* W2n = co2 + j * (- si2)
-* W3n = co3 + j * (- si3)
-*
-* Butterfly implementation:
-* xa' = xa + xb + xc + xd
-* ya' = ya + yb + yc + yd
-* xb' = (xa+yb-xc-yd)* co1 + (ya-xb-yc+xd)* (si1)
-* yb' = (ya-xb-yc+xd)* co1 - (xa+yb-xc-yd)* (si1)
-* xc' = (xa-xb+xc-xd)* co2 + (ya-yb+yc-yd)* (si2)
-* yc' = (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)
-*
-*/
-
-/**
- * @brief Core function for the Q31 CFFT butterfly process.
- * @param[in, out] *pSrc points to the in-place buffer of Q31 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.
- * @return none.
- */
-
-void arm_radix4_butterfly_q31(
- q31_t * pSrc,
- uint32_t fftLen,
- q31_t * pCoef,
- uint32_t twidCoefModifier)
-{
- uint32_t n1, n2, ia1, ia2, ia3, i0, i1, i2, i3, j, k;
- q31_t t1, t2, r1, r2, s1, s2, co1, co2, co3, si1, si2, si3;
-
- q31_t xa, xb, xc, xd;
- q31_t ya, yb, yc, yd;
- q31_t xa_out, xb_out, xc_out, xd_out;
- q31_t ya_out, yb_out, yc_out, yd_out;
-
- q31_t *ptr1;
- q63_t xaya, xbyb, xcyc, xdyd;
- /* Total process is divided into three stages */
-
- /* process first stage, middle stages, & last stage */
-
-
- /* start of first stage process */
-
- /* 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/2u], pSrc[i0 + 3fftLen/4] */
- i1 = i0 + n2;
- i2 = i1 + n2;
- i3 = i2 + n2;
-
- /* input is in 1.31(q31) format and provide 4 guard bits for the input */
-
- /* Butterfly implementation */
- /* xa + xc */
- r1 = (pSrc[(2u * i0)] >> 4u) + (pSrc[(2u * i2)] >> 4u);
- /* xa - xc */
- r2 = (pSrc[2u * i0] >> 4u) - (pSrc[2u * i2] >> 4u);
-
- /* xb + xd */
- t1 = (pSrc[2u * i1] >> 4u) + (pSrc[2u * i3] >> 4u);
-
- /* ya + yc */
- s1 = (pSrc[(2u * i0) + 1u] >> 4u) + (pSrc[(2u * i2) + 1u] >> 4u);
- /* ya - yc */
- s2 = (pSrc[(2u * i0) + 1u] >> 4u) - (pSrc[(2u * i2) + 1u] >> 4u);
-
- /* xa' = xa + xb + xc + xd */
- pSrc[2u * i0] = (r1 + t1);
- /* (xa + xc) - (xb + xd) */
- r1 = r1 - t1;
- /* yb + yd */
- t2 = (pSrc[(2u * i1) + 1u] >> 4u) + (pSrc[(2u * i3) + 1u] >> 4u);
-
- /* 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] >> 4u) - (pSrc[(2u * i3) + 1u] >> 4u);
- /* xb - xd */
- t2 = (pSrc[2u * i1] >> 4u) - (pSrc[2u * i3] >> 4u);
-
- /* index calculation for the coefficients */
- ia2 = 2u * ia1;
- co2 = pCoef[ia2 * 2u];
- si2 = pCoef[(ia2 * 2u) + 1u];
-
- /* xc' = (xa-xb+xc-xd)co2 + (ya-yb+yc-yd)(si2) */
- pSrc[2u * i1] = (((int32_t) (((q63_t) r1 * co2) >> 32)) +
- ((int32_t) (((q63_t) s1 * si2) >> 32))) << 1u;
-
- /* yc' = (ya-yb+yc-yd)co2 - (xa-xb+xc-xd)(si2) */
- pSrc[(2u * i1) + 1u] = (((int32_t) (((q63_t) s1 * co2) >> 32)) -
- ((int32_t) (((q63_t) r1 * si2) >> 32))) << 1u;
-
- /* (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;
-
- co1 = pCoef[ia1 * 2u];
- si1 = pCoef[(ia1 * 2u) + 1u];
-
- /* xb' = (xa+yb-xc-yd)co1 + (ya-xb-yc+xd)(si1) */
- pSrc[2u * i2] = (((int32_t) (((q63_t) r1 * co1) >> 32)) +
- ((int32_t) (((q63_t) s1 * si1) >> 32))) << 1u;
-
- /* yb' = (ya-xb-yc+xd)co1 - (xa+yb-xc-yd)(si1) */
- pSrc[(2u * i2) + 1u] = (((int32_t) (((q63_t) s1 * co1) >> 32)) -
- ((int32_t) (((q63_t) r1 * si1) >> 32))) << 1u;
-
- /* index calculation for the coefficients */
- ia3 = 3u * ia1;
- co3 = pCoef[ia3 * 2u];
- si3 = pCoef[(ia3 * 2u) + 1u];
-
- /* xd' = (xa-yb-xc+yd)co3 + (ya+xb-yc-xd)(si3) */
- pSrc[2u * i3] = (((int32_t) (((q63_t) r2 * co3) >> 32)) +
- ((int32_t) (((q63_t) s2 * si3) >> 32))) << 1u;
-
- /* yd' = (ya+xb-yc-xd)co3 - (xa-yb-xc+yd)(si3) */
- pSrc[(2u * i3) + 1u] = (((int32_t) (((q63_t) s2 * co3) >> 32)) -
- ((int32_t) (((q63_t) r2 * si3) >> 32))) << 1u;
-
- /* Twiddle coefficients index modifier */
- ia1 = ia1 + twidCoefModifier;
-
- /* Updating input index */
- i0 = i0 + 1u;
-
- } while(--j);
-
- /* end of first stage process */
-
- /* data is in 5.27(q27) format */
-
-
- /* start of Middle stages process */
-
-
- /* each stage in middle stages provides two down scaling of the input */
-
- twidCoefModifier <<= 2u;
-
-
- for (k = fftLen / 4u; 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/2u], 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];
-
- /* xb + xd */
- t1 = pSrc[2u * i1] + pSrc[2u * i3];
-
- /* xa' = xa + xb + xc + xd */
- pSrc[2u * i0] = (r1 + t1) >> 2u;
- /* 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) >> 2u;
-
- /* (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] = (((int32_t) (((q63_t) r1 * co2) >> 32)) +
- ((int32_t) (((q63_t) s1 * si2) >> 32))) >> 1u;
-
- /* yc' = (ya-yb+yc-yd)co2 - (xa-xb+xc-xd)(si2) */
- pSrc[(2u * i1) + 1u] = (((int32_t) (((q63_t) s1 * co2) >> 32)) -
- ((int32_t) (((q63_t) r1 * si2) >> 32))) >> 1u;
-
- /* (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] = (((int32_t) (((q63_t) r1 * co1) >> 32)) +
- ((int32_t) (((q63_t) s1 * si1) >> 32))) >> 1u;
-
- /* yb' = (ya-xb-yc+xd)co1 - (xa+yb-xc-yd)(si1) */
- pSrc[(2u * i2) + 1u] = (((int32_t) (((q63_t) s1 * co1) >> 32)) -
- ((int32_t) (((q63_t) r1 * si1) >> 32))) >> 1u;
-
- /* xd' = (xa-yb-xc+yd)co3 + (ya+xb-yc-xd)(si3) */
- pSrc[2u * i3] = (((int32_t) (((q63_t) r2 * co3) >> 32)) +
- ((int32_t) (((q63_t) s2 * si3) >> 32))) >> 1u;
-
- /* yd' = (ya+xb-yc-xd)co3 - (xa-yb-xc+yd)(si3) */
- pSrc[(2u * i3) + 1u] = (((int32_t) (((q63_t) s2 * co3) >> 32)) -
- ((int32_t) (((q63_t) r2 * si3) >> 32))) >> 1u;
- }
- }
- twidCoefModifier <<= 2u;
- }
-
- /* End of Middle stages process */
-
- /* data is in 11.21(q21) format for the 1024 point as there are 3 middle stages */
- /* data is in 9.23(q23) format for the 256 point as there are 2 middle stages */
- /* data is in 7.25(q25) format for the 64 point as there are 1 middle stage */
- /* data is in 5.27(q27) format for the 16 point as there are no middle stages */
-
-
- /* start of Last stage process */
- /* Initializations for the last stage */
- j = fftLen >> 2;
- ptr1 = &pSrc[0];
-
- /* Calculations of last stage */
- do
- {
-
-#ifndef ARM_MATH_BIG_ENDIAN
-
- /* Read xa (real), ya(imag) input */
- xaya = *__SIMD64(ptr1)++;
- xa = (q31_t) xaya;
- ya = (q31_t) (xaya >> 32);
-
- /* Read xb (real), yb(imag) input */
- xbyb = *__SIMD64(ptr1)++;
- xb = (q31_t) xbyb;
- yb = (q31_t) (xbyb >> 32);
-
- /* Read xc (real), yc(imag) input */
- xcyc = *__SIMD64(ptr1)++;
- xc = (q31_t) xcyc;
- yc = (q31_t) (xcyc >> 32);
-
- /* Read xc (real), yc(imag) input */
- xdyd = *__SIMD64(ptr1)++;
- xd = (q31_t) xdyd;
- yd = (q31_t) (xdyd >> 32);
-
-#else
-
- /* Read xa (real), ya(imag) input */
- xaya = *__SIMD64(ptr1)++;
- ya = (q31_t) xaya;
- xa = (q31_t) (xaya >> 32);
-
- /* Read xb (real), yb(imag) input */
- xbyb = *__SIMD64(ptr1)++;
- yb = (q31_t) xbyb;
- xb = (q31_t) (xbyb >> 32);
-
- /* Read xc (real), yc(imag) input */
- xcyc = *__SIMD64(ptr1)++;
- yc = (q31_t) xcyc;
- xc = (q31_t) (xcyc >> 32);
-
- /* Read xc (real), yc(imag) input */
- xdyd = *__SIMD64(ptr1)++;
- yd = (q31_t) xdyd;
- xd = (q31_t) (xdyd >> 32);
-
-
-#endif
-
- /* xa' = xa + xb + xc + xd */
- xa_out = xa + xb + xc + xd;
-
- /* ya' = ya + yb + yc + yd */
- ya_out = ya + yb + yc + yd;
-
- /* pointer updation for writing */
- ptr1 = ptr1 - 8u;
-
- /* writing xa' and ya' */
- *ptr1++ = xa_out;
- *ptr1++ = ya_out;
-
- xc_out = (xa - xb + xc - xd);
- yc_out = (ya - yb + yc - yd);
-
- /* writing xc' and yc' */
- *ptr1++ = xc_out;
- *ptr1++ = yc_out;
-
- xb_out = (xa + yb - xc - yd);
- yb_out = (ya - xb - yc + xd);
-
- /* writing xb' and yb' */
- *ptr1++ = xb_out;
- *ptr1++ = yb_out;
-
- xd_out = (xa - yb - xc + yd);
- yd_out = (ya + xb - yc - xd);
-
- /* writing xd' and yd' */
- *ptr1++ = xd_out;
- *ptr1++ = yd_out;
-
-
- } while(--j);
-
- /* output is in 11.21(q21) format for the 1024 point */
- /* output is in 9.23(q23) format for the 256 point */
- /* output is in 7.25(q25) format for the 64 point */
- /* output is in 5.27(q27) format for the 16 point */
-
- /* End of last stage process */
-
-}
-
-
-/**
- * @brief Core function for the Q31 CIFFT butterfly process.
- * @param[in, out] *pSrc points to the in-place buffer of Q31 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.
- * @return none.
- */
-
-
-/*
-* Radix-4 IFFT algorithm used is :
-*
-* CIFFT uses same twiddle coefficients as CFFT Function
-* x[k] = x[n] + (j)k * x[n + fftLen/4] + (-1)k * x[n+fftLen/2] + (-j)k * x[n+3*fftLen/4]
-*
-*
-* IFFT is implemented with following changes in equations from FFT
-*
-* Input real and imaginary data:
-* 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
-*
-*
-* Output real and imaginary data:
-* x(4r) = xa'+ j * ya'
-* x(4r+1) = xb'+ j * yb'
-* x(4r+2) = xc'+ j * yc'
-* x(4r+3) = xd'+ j * yd'
-*
-*
-* Twiddle factors for radix-4 IFFT:
-* Wn = co1 + j * (si1)
-* W2n = co2 + j * (si2)
-* W3n = co3 + j * (si3)
-
-* The real and imaginary output values for the radix-4 butterfly are
-* xa' = xa + xb + xc + xd
-* ya' = ya + yb + yc + yd
-* xb' = (xa-yb-xc+yd)* co1 - (ya+xb-yc-xd)* (si1)
-* yb' = (ya+xb-yc-xd)* co1 + (xa-yb-xc+yd)* (si1)
-* xc' = (xa-xb+xc-xd)* co2 - (ya-yb+yc-yd)* (si2)
-* yc' = (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)
-*
-*/
-
-void arm_radix4_butterfly_inverse_q31(
- q31_t * pSrc,
- uint32_t fftLen,
- q31_t * pCoef,
- uint32_t twidCoefModifier)
-{
- uint32_t n1, n2, ia1, ia2, ia3, i0, i1, i2, i3, j, k;
- q31_t t1, t2, r1, r2, s1, s2, co1, co2, co3, si1, si2, si3;
- q31_t xa, xb, xc, xd;
- q31_t ya, yb, yc, yd;
- q31_t xa_out, xb_out, xc_out, xd_out;
- q31_t ya_out, yb_out, yc_out, yd_out;
-
- q31_t *ptr1;
- q63_t xaya, xbyb, xcyc, xdyd;
-
- /* input is be 1.31(q31) format for all FFT sizes */
- /* Total process is divided into three stages */
- /* process first stage, middle stages, & last stage */
-
- /* Start of first stage process */
-
- /* Initializations for the first stage */
- n2 = fftLen;
- n1 = n2;
- /* n2 = fftLen/4 */
- n2 >>= 2u;
- i0 = 0u;
- ia1 = 0u;
-
- j = n2;
-
- do
- {
-
- /* input is in 1.31(q31) format and provide 4 guard bits for the input */
-
- /* index calculation for the input as, */
- /* pSrc[i0 + 0], pSrc[i0 + fftLen/4], pSrc[i0 + fftLen/2u], pSrc[i0 + 3fftLen/4] */
- i1 = i0 + n2;
- i2 = i1 + n2;
- i3 = i2 + n2;
-
- /* Butterfly implementation */
- /* xa + xc */
- r1 = (pSrc[2u * i0] >> 4u) + (pSrc[2u * i2] >> 4u);
- /* xa - xc */
- r2 = (pSrc[2u * i0] >> 4u) - (pSrc[2u * i2] >> 4u);
-
- /* xb + xd */
- t1 = (pSrc[2u * i1] >> 4u) + (pSrc[2u * i3] >> 4u);
-
- /* ya + yc */
- s1 = (pSrc[(2u * i0) + 1u] >> 4u) + (pSrc[(2u * i2) + 1u] >> 4u);
- /* ya - yc */
- s2 = (pSrc[(2u * i0) + 1u] >> 4u) - (pSrc[(2u * i2) + 1u] >> 4u);
-
- /* xa' = xa + xb + xc + xd */
- pSrc[2u * i0] = (r1 + t1);
- /* (xa + xc) - (xb + xd) */
- r1 = r1 - t1;
- /* yb + yd */
- t2 = (pSrc[(2u * i1) + 1u] >> 4u) + (pSrc[(2u * i3) + 1u] >> 4u);
- /* 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] >> 4u) - (pSrc[(2u * i3) + 1u] >> 4u);
- /* xb - xd */
- t2 = (pSrc[2u * i1] >> 4u) - (pSrc[2u * i3] >> 4u);
-
- /* index calculation for the coefficients */
- ia2 = 2u * ia1;
- co2 = pCoef[ia2 * 2u];
- si2 = pCoef[(ia2 * 2u) + 1u];
-
- /* xc' = (xa-xb+xc-xd)co2 - (ya-yb+yc-yd)(si2) */
- pSrc[2u * i1] = (((int32_t) (((q63_t) r1 * co2) >> 32)) -
- ((int32_t) (((q63_t) s1 * si2) >> 32))) << 1u;
-
- /* yc' = (ya-yb+yc-yd)co2 + (xa-xb+xc-xd)(si2) */
- pSrc[2u * i1 + 1u] = (((int32_t) (((q63_t) s1 * co2) >> 32)) +
- ((int32_t) (((q63_t) r1 * si2) >> 32))) << 1u;
-
- /* (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;
-
- co1 = pCoef[ia1 * 2u];
- si1 = pCoef[(ia1 * 2u) + 1u];
-
- /* xb' = (xa+yb-xc-yd)co1 - (ya-xb-yc+xd)(si1) */
- pSrc[2u * i2] = (((int32_t) (((q63_t) r1 * co1) >> 32)) -
- ((int32_t) (((q63_t) s1 * si1) >> 32))) << 1u;
-
- /* yb' = (ya-xb-yc+xd)co1 + (xa+yb-xc-yd)(si1) */
- pSrc[(2u * i2) + 1u] = (((int32_t) (((q63_t) s1 * co1) >> 32)) +
- ((int32_t) (((q63_t) r1 * si1) >> 32))) << 1u;
-
- /* index calculation for the coefficients */
- ia3 = 3u * ia1;
- co3 = pCoef[ia3 * 2u];
- si3 = pCoef[(ia3 * 2u) + 1u];
-
- /* xd' = (xa-yb-xc+yd)co3 - (ya+xb-yc-xd)(si3) */
- pSrc[2u * i3] = (((int32_t) (((q63_t) r2 * co3) >> 32)) -
- ((int32_t) (((q63_t) s2 * si3) >> 32))) << 1u;
-
- /* yd' = (ya+xb-yc-xd)co3 + (xa-yb-xc+yd)(si3) */
- pSrc[(2u * i3) + 1u] = (((int32_t) (((q63_t) s2 * co3) >> 32)) +
- ((int32_t) (((q63_t) r2 * si3) >> 32))) << 1u;
-
- /* Twiddle coefficients index modifier */
- ia1 = ia1 + twidCoefModifier;
-
- /* Updating input index */
- i0 = i0 + 1u;
-
- } while(--j);
-
- /* data is in 5.27(q27) format */
- /* each stage provides two down scaling of the input */
-
-
- /* Start of Middle stages process */
-
- twidCoefModifier <<= 2u;
-
- /* Calculation of second stage to excluding last stage */
- for (k = fftLen / 4u; k > 4u; k >>= 2u)
- {
- /* Initializations for the first stage */
- n1 = n2;
- n2 >>= 2u;
- ia1 = 0u;
-
- for (j = 0; 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/2u], 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];
-
- /* xb + xd */
- t1 = pSrc[2u * i1] + pSrc[2u * i3];
-
- /* xa' = xa + xb + xc + xd */
- pSrc[2u * i0] = (r1 + t1) >> 2u;
- /* 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) >> 2u;
-
- /* (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] = (((int32_t) (((q63_t) r1 * co2) >> 32u)) -
- ((int32_t) (((q63_t) s1 * si2) >> 32u))) >> 1u;
-
- /* yc' = (ya-yb+yc-yd)co2 + (xa-xb+xc-xd)(si2) */
- pSrc[(2u * i1) + 1u] =
- (((int32_t) (((q63_t) s1 * co2) >> 32u)) +
- ((int32_t) (((q63_t) r1 * si2) >> 32u))) >> 1u;
-
- /* (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] = (((int32_t) (((q63_t) r1 * co1) >> 32)) -
- ((int32_t) (((q63_t) s1 * si1) >> 32))) >> 1u;
-
- /* yb' = (ya-xb-yc+xd)co1 + (xa+yb-xc-yd)(si1) */
- pSrc[(2u * i2) + 1u] = (((int32_t) (((q63_t) s1 * co1) >> 32)) +
- ((int32_t) (((q63_t) r1 * si1) >> 32))) >> 1u;
-
- /* xd' = (xa-yb-xc+yd)co3 - (ya+xb-yc-xd)(si3) */
- pSrc[(2u * i3)] = (((int32_t) (((q63_t) r2 * co3) >> 32)) -
- ((int32_t) (((q63_t) s2 * si3) >> 32))) >> 1u;
-
- /* yd' = (ya+xb-yc-xd)co3 + (xa-yb-xc+yd)(si3) */
- pSrc[(2u * i3) + 1u] = (((int32_t) (((q63_t) s2 * co3) >> 32)) +
- ((int32_t) (((q63_t) r2 * si3) >> 32))) >> 1u;
- }
- }
- twidCoefModifier <<= 2u;
- }
-
- /* End of Middle stages process */
-
- /* data is in 11.21(q21) format for the 1024 point as there are 3 middle stages */
- /* data is in 9.23(q23) format for the 256 point as there are 2 middle stages */
- /* data is in 7.25(q25) format for the 64 point as there are 1 middle stage */
- /* data is in 5.27(q27) format for the 16 point as there are no middle stages */
-
-
- /* Start of last stage process */
-
-
- /* Initializations for the last stage */
- j = fftLen >> 2;
- ptr1 = &pSrc[0];
-
- /* Calculations of last stage */
- do
- {
-#ifndef ARM_MATH_BIG_ENDIAN
- /* Read xa (real), ya(imag) input */
- xaya = *__SIMD64(ptr1)++;
- xa = (q31_t) xaya;
- ya = (q31_t) (xaya >> 32);
-
- /* Read xb (real), yb(imag) input */
- xbyb = *__SIMD64(ptr1)++;
- xb = (q31_t) xbyb;
- yb = (q31_t) (xbyb >> 32);
-
- /* Read xc (real), yc(imag) input */
- xcyc = *__SIMD64(ptr1)++;
- xc = (q31_t) xcyc;
- yc = (q31_t) (xcyc >> 32);
-
- /* Read xc (real), yc(imag) input */
- xdyd = *__SIMD64(ptr1)++;
- xd = (q31_t) xdyd;
- yd = (q31_t) (xdyd >> 32);
-
-#else
-
- /* Read xa (real), ya(imag) input */
- xaya = *__SIMD64(ptr1)++;
- ya = (q31_t) xaya;
- xa = (q31_t) (xaya >> 32);
-
- /* Read xb (real), yb(imag) input */
- xbyb = *__SIMD64(ptr1)++;
- yb = (q31_t) xbyb;
- xb = (q31_t) (xbyb >> 32);
-
- /* Read xc (real), yc(imag) input */
- xcyc = *__SIMD64(ptr1)++;
- yc = (q31_t) xcyc;
- xc = (q31_t) (xcyc >> 32);
-
- /* Read xc (real), yc(imag) input */
- xdyd = *__SIMD64(ptr1)++;
- yd = (q31_t) xdyd;
- xd = (q31_t) (xdyd >> 32);
-
-
-#endif
-
- /* xa' = xa + xb + xc + xd */
- xa_out = xa + xb + xc + xd;
-
- /* ya' = ya + yb + yc + yd */
- ya_out = ya + yb + yc + yd;
-
- /* pointer updation for writing */
- ptr1 = ptr1 - 8u;
-
- /* writing xa' and ya' */
- *ptr1++ = xa_out;
- *ptr1++ = ya_out;
-
- xc_out = (xa - xb + xc - xd);
- yc_out = (ya - yb + yc - yd);
-
- /* writing xc' and yc' */
- *ptr1++ = xc_out;
- *ptr1++ = yc_out;
-
- xb_out = (xa - yb - xc + yd);
- yb_out = (ya + xb - yc - xd);
-
- /* writing xb' and yb' */
- *ptr1++ = xb_out;
- *ptr1++ = yb_out;
-
- xd_out = (xa + yb - xc - yd);
- yd_out = (ya - xb - yc + xd);
-
- /* writing xd' and yd' */
- *ptr1++ = xd_out;
- *ptr1++ = yd_out;
-
-
- } while(--j);
-
- /* output is in 11.21(q21) format for the 1024 point */
- /* output is in 9.23(q23) format for the 256 point */
- /* output is in 7.25(q25) format for the 64 point */
- /* output is in 5.27(q27) format for the 16 point */
-
- /* End of last stage process */
-}
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