diff options
Diffstat (limited to 'fw/hid-dials/Drivers/CMSIS/DSP/Source/TransformFunctions/arm_cfft_radix4_q15.c')
| -rw-r--r-- | fw/hid-dials/Drivers/CMSIS/DSP/Source/TransformFunctions/arm_cfft_radix4_q15.c | 1910 |
1 files changed, 0 insertions, 1910 deletions
diff --git a/fw/hid-dials/Drivers/CMSIS/DSP/Source/TransformFunctions/arm_cfft_radix4_q15.c b/fw/hid-dials/Drivers/CMSIS/DSP/Source/TransformFunctions/arm_cfft_radix4_q15.c deleted file mode 100644 index 140fa53..0000000 --- a/fw/hid-dials/Drivers/CMSIS/DSP/Source/TransformFunctions/arm_cfft_radix4_q15.c +++ /dev/null @@ -1,1910 +0,0 @@ -/* ----------------------------------------------------------------------
- * Project: CMSIS DSP Library
- * Title: arm_cfft_radix4_q15.c
- * Description: This file has function definition of Radix-4 FFT & IFFT function and
- * In-place bit reversal using bit reversal table
- *
- * $Date: 27. January 2017
- * $Revision: V.1.5.1
- *
- * Target Processor: Cortex-M cores
- * -------------------------------------------------------------------- */
-/*
- * Copyright (C) 2010-2017 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"
-
-
-void arm_radix4_butterfly_q15(
- q15_t * pSrc16,
- uint32_t fftLen,
- q15_t * pCoef16,
- uint32_t twidCoefModifier);
-
-void arm_radix4_butterfly_inverse_q15(
- q15_t * pSrc16,
- uint32_t fftLen,
- q15_t * pCoef16,
- uint32_t twidCoefModifier);
-
-void arm_bitreversal_q15(
- q15_t * pSrc,
- uint32_t fftLen,
- uint16_t bitRevFactor,
- uint16_t * pBitRevTab);
-
-/**
- * @ingroup groupTransforms
- */
-
-/**
- * @addtogroup ComplexFFT
- * @{
- */
-
-
-/**
- * @details
- * @brief Processing function for the Q15 CFFT/CIFFT.
- * @deprecated Do not use this function. It has been superseded by \ref arm_cfft_q15 and will be removed
- * @param[in] *S points to an instance of the Q15 CFFT/CIFFT structure.
- * @param[in, out] *pSrc points to the complex data buffer. 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 CFFTQ15.gif "Input and Output Formats for Q15 CFFT"
- * \image html CIFFTQ15.gif "Input and Output Formats for Q15 CIFFT"
- */
-
-void arm_cfft_radix4_q15(
- const arm_cfft_radix4_instance_q15 * S,
- q15_t * pSrc)
-{
- if (S->ifftFlag == 1U)
- {
- /* Complex IFFT radix-4 */
- arm_radix4_butterfly_inverse_q15(pSrc, S->fftLen, S->pTwiddle, S->twidCoefModifier);
- }
- else
- {
- /* Complex FFT radix-4 */
- arm_radix4_butterfly_q15(pSrc, S->fftLen, S->pTwiddle, S->twidCoefModifier);
- }
-
- if (S->bitReverseFlag == 1U)
- {
- /* Bit Reversal */
- arm_bitreversal_q15(pSrc, S->fftLen, S->bitRevFactor, S->pBitRevTable);
- }
-
-}
-
-/**
- * @} end of ComplexFFT 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)
-
-* 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)
-*
-*/
-
-/**
- * @brief Core function for the Q15 CFFT butterfly process.
- * @param[in, out] *pSrc16 points to the in-place buffer of Q15 data type.
- * @param[in] fftLen length of the FFT.
- * @param[in] *pCoef16 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_q15(
- q15_t * pSrc16,
- uint32_t fftLen,
- q15_t * pCoef16,
- uint32_t twidCoefModifier)
-{
-
-#if defined (ARM_MATH_DSP)
-
- /* Run the below code for Cortex-M4 and Cortex-M3 */
-
- q31_t R, S, T, U;
- q31_t C1, C2, C3, out1, out2;
- uint32_t n1, n2, ic, i0, j, k;
-
- q15_t *ptr1;
- q15_t *pSi0;
- q15_t *pSi1;
- q15_t *pSi2;
- q15_t *pSi3;
-
- q31_t xaya, xbyb, xcyc, xdyd;
-
- /* Total process is divided into three stages */
-
- /* process first stage, middle stages, & last stage */
-
- /* Initializations for the first stage */
- n2 = fftLen;
- n1 = n2;
-
- /* n2 = fftLen/4 */
- n2 >>= 2U;
-
- /* Index for twiddle coefficient */
- ic = 0U;
-
- /* Index for input read and output write */
- j = n2;
-
- pSi0 = pSrc16;
- pSi1 = pSi0 + 2 * n2;
- pSi2 = pSi1 + 2 * n2;
- pSi3 = pSi2 + 2 * n2;
-
- /* Input is in 1.15(q15) format */
-
- /* start of first stage process */
- do
- {
- /* Butterfly implementation */
-
- /* Reading i0, i0+fftLen/2 inputs */
- /* Read ya (real), xa(imag) input */
- T = _SIMD32_OFFSET(pSi0);
- T = __SHADD16(T, 0); // this is just a SIMD arithmetic shift right by 1
- T = __SHADD16(T, 0); // it turns out doing this twice is 2 cycles, the alternative takes 3 cycles
- //in = ((int16_t) (T & 0xFFFF)) >> 2; // alternative code that takes 3 cycles
- //T = ((T >> 2) & 0xFFFF0000) | (in & 0xFFFF);
-
- /* Read yc (real), xc(imag) input */
- S = _SIMD32_OFFSET(pSi2);
- S = __SHADD16(S, 0);
- S = __SHADD16(S, 0);
-
- /* R = packed((ya + yc), (xa + xc) ) */
- R = __QADD16(T, S);
-
- /* S = packed((ya - yc), (xa - xc) ) */
- S = __QSUB16(T, S);
-
- /* Reading i0+fftLen/4 , i0+3fftLen/4 inputs */
- /* Read yb (real), xb(imag) input */
- T = _SIMD32_OFFSET(pSi1);
- T = __SHADD16(T, 0);
- T = __SHADD16(T, 0);
-
- /* Read yd (real), xd(imag) input */
- U = _SIMD32_OFFSET(pSi3);
- U = __SHADD16(U, 0);
- U = __SHADD16(U, 0);
-
- /* T = packed((yb + yd), (xb + xd) ) */
- T = __QADD16(T, U);
-
- /* writing the butterfly processed i0 sample */
- /* xa' = xa + xb + xc + xd */
- /* ya' = ya + yb + yc + yd */
- _SIMD32_OFFSET(pSi0) = __SHADD16(R, T);
- pSi0 += 2;
-
- /* R = packed((ya + yc) - (yb + yd), (xa + xc)- (xb + xd)) */
- R = __QSUB16(R, T);
-
- /* co2 & si2 are read from SIMD Coefficient pointer */
- C2 = _SIMD32_OFFSET(pCoef16 + (4U * ic));
-
-#ifndef ARM_MATH_BIG_ENDIAN
-
- /* xc' = (xa-xb+xc-xd)* co2 + (ya-yb+yc-yd)* (si2) */
- out1 = __SMUAD(C2, R) >> 16U;
- /* yc' = (ya-yb+yc-yd)* co2 - (xa-xb+xc-xd)* (si2) */
- out2 = __SMUSDX(C2, R);
-
-#else
-
- /* xc' = (ya-yb+yc-yd)* co2 - (xa-xb+xc-xd)* (si2) */
- out1 = __SMUSDX(R, C2) >> 16U;
- /* yc' = (xa-xb+xc-xd)* co2 + (ya-yb+yc-yd)* (si2) */
- out2 = __SMUAD(C2, R);
-
-#endif /* #ifndef ARM_MATH_BIG_ENDIAN */
-
- /* Reading i0+fftLen/4 */
- /* T = packed(yb, xb) */
- T = _SIMD32_OFFSET(pSi1);
- T = __SHADD16(T, 0);
- T = __SHADD16(T, 0);
-
- /* writing the butterfly processed i0 + fftLen/4 sample */
- /* writing output(xc', yc') in little endian format */
- _SIMD32_OFFSET(pSi1) =
- (q31_t) ((out2) & 0xFFFF0000) | (out1 & 0x0000FFFF);
- pSi1 += 2;
-
- /* Butterfly calculations */
- /* U = packed(yd, xd) */
- U = _SIMD32_OFFSET(pSi3);
- U = __SHADD16(U, 0);
- U = __SHADD16(U, 0);
-
- /* T = packed(yb-yd, xb-xd) */
- T = __QSUB16(T, U);
-
-#ifndef ARM_MATH_BIG_ENDIAN
-
- /* R = packed((ya-yc) + (xb- xd) , (xa-xc) - (yb-yd)) */
- R = __QASX(S, T);
- /* S = packed((ya-yc) - (xb- xd), (xa-xc) + (yb-yd)) */
- S = __QSAX(S, T);
-
-#else
-
- /* R = packed((ya-yc) + (xb- xd) , (xa-xc) - (yb-yd)) */
- R = __QSAX(S, T);
- /* S = packed((ya-yc) - (xb- xd), (xa-xc) + (yb-yd)) */
- S = __QASX(S, T);
-
-#endif /* #ifndef ARM_MATH_BIG_ENDIAN */
-
- /* co1 & si1 are read from SIMD Coefficient pointer */
- C1 = _SIMD32_OFFSET(pCoef16 + (2U * ic));
- /* Butterfly process for the i0+fftLen/2 sample */
-
-#ifndef ARM_MATH_BIG_ENDIAN
-
- /* xb' = (xa+yb-xc-yd)* co1 + (ya-xb-yc+xd)* (si1) */
- out1 = __SMUAD(C1, S) >> 16U;
- /* yb' = (ya-xb-yc+xd)* co1 - (xa+yb-xc-yd)* (si1) */
- out2 = __SMUSDX(C1, S);
-
-#else
-
- /* xb' = (ya-xb-yc+xd)* co1 - (xa+yb-xc-yd)* (si1) */
- out1 = __SMUSDX(S, C1) >> 16U;
- /* yb' = (xa+yb-xc-yd)* co1 + (ya-xb-yc+xd)* (si1) */
- out2 = __SMUAD(C1, S);
-
-#endif /* #ifndef ARM_MATH_BIG_ENDIAN */
-
- /* writing output(xb', yb') in little endian format */
- _SIMD32_OFFSET(pSi2) =
- ((out2) & 0xFFFF0000) | ((out1) & 0x0000FFFF);
- pSi2 += 2;
-
-
- /* co3 & si3 are read from SIMD Coefficient pointer */
- C3 = _SIMD32_OFFSET(pCoef16 + (6U * ic));
- /* Butterfly process for the i0+3fftLen/4 sample */
-
-#ifndef ARM_MATH_BIG_ENDIAN
-
- /* xd' = (xa-yb-xc+yd)* co3 + (ya+xb-yc-xd)* (si3) */
- out1 = __SMUAD(C3, R) >> 16U;
- /* yd' = (ya+xb-yc-xd)* co3 - (xa-yb-xc+yd)* (si3) */
- out2 = __SMUSDX(C3, R);
-
-#else
-
- /* xd' = (ya+xb-yc-xd)* co3 - (xa-yb-xc+yd)* (si3) */
- out1 = __SMUSDX(R, C3) >> 16U;
- /* yd' = (xa-yb-xc+yd)* co3 + (ya+xb-yc-xd)* (si3) */
- out2 = __SMUAD(C3, R);
-
-#endif /* #ifndef ARM_MATH_BIG_ENDIAN */
-
- /* writing output(xd', yd') in little endian format */
- _SIMD32_OFFSET(pSi3) =
- ((out2) & 0xFFFF0000) | (out1 & 0x0000FFFF);
- pSi3 += 2;
-
- /* Twiddle coefficients index modifier */
- ic = ic + twidCoefModifier;
-
- } while (--j);
- /* data is in 4.11(q11) format */
-
- /* end of first stage process */
-
-
- /* start of middle stage process */
-
- /* Twiddle coefficients index modifier */
- twidCoefModifier <<= 2U;
-
- /* Calculation of Middle stage */
- for (k = fftLen / 4U; k > 4U; k >>= 2U)
- {
- /* Initializations for the middle stage */
- n1 = n2;
- n2 >>= 2U;
- ic = 0U;
-
- for (j = 0U; j <= (n2 - 1U); j++)
- {
- /* index calculation for the coefficients */
- C1 = _SIMD32_OFFSET(pCoef16 + (2U * ic));
- C2 = _SIMD32_OFFSET(pCoef16 + (4U * ic));
- C3 = _SIMD32_OFFSET(pCoef16 + (6U * ic));
-
- /* Twiddle coefficients index modifier */
- ic = ic + twidCoefModifier;
-
- pSi0 = pSrc16 + 2 * j;
- pSi1 = pSi0 + 2 * n2;
- pSi2 = pSi1 + 2 * n2;
- pSi3 = pSi2 + 2 * n2;
-
- /* Butterfly implementation */
- for (i0 = j; i0 < fftLen; i0 += n1)
- {
- /* Reading i0, i0+fftLen/2 inputs */
- /* Read ya (real), xa(imag) input */
- T = _SIMD32_OFFSET(pSi0);
-
- /* Read yc (real), xc(imag) input */
- S = _SIMD32_OFFSET(pSi2);
-
- /* R = packed( (ya + yc), (xa + xc)) */
- R = __QADD16(T, S);
-
- /* S = packed((ya - yc), (xa - xc)) */
- S = __QSUB16(T, S);
-
- /* Reading i0+fftLen/4 , i0+3fftLen/4 inputs */
- /* Read yb (real), xb(imag) input */
- T = _SIMD32_OFFSET(pSi1);
-
- /* Read yd (real), xd(imag) input */
- U = _SIMD32_OFFSET(pSi3);
-
- /* T = packed( (yb + yd), (xb + xd)) */
- T = __QADD16(T, U);
-
- /* writing the butterfly processed i0 sample */
-
- /* xa' = xa + xb + xc + xd */
- /* ya' = ya + yb + yc + yd */
- out1 = __SHADD16(R, T);
- out1 = __SHADD16(out1, 0);
- _SIMD32_OFFSET(pSi0) = out1;
- pSi0 += 2 * n1;
-
- /* R = packed( (ya + yc) - (yb + yd), (xa + xc) - (xb + xd)) */
- R = __SHSUB16(R, T);
-
-#ifndef ARM_MATH_BIG_ENDIAN
-
- /* (ya-yb+yc-yd)* (si2) + (xa-xb+xc-xd)* co2 */
- out1 = __SMUAD(C2, R) >> 16U;
-
- /* (ya-yb+yc-yd)* co2 - (xa-xb+xc-xd)* (si2) */
- out2 = __SMUSDX(C2, R);
-
-#else
-
- /* (ya-yb+yc-yd)* co2 - (xa-xb+xc-xd)* (si2) */
- out1 = __SMUSDX(R, C2) >> 16U;
-
- /* (ya-yb+yc-yd)* (si2) + (xa-xb+xc-xd)* co2 */
- out2 = __SMUAD(C2, R);
-
-#endif /* #ifndef ARM_MATH_BIG_ENDIAN */
-
- /* Reading i0+3fftLen/4 */
- /* Read yb (real), xb(imag) input */
- T = _SIMD32_OFFSET(pSi1);
-
- /* writing the butterfly processed i0 + fftLen/4 sample */
- /* xc' = (xa-xb+xc-xd)* co2 + (ya-yb+yc-yd)* (si2) */
- /* yc' = (ya-yb+yc-yd)* co2 - (xa-xb+xc-xd)* (si2) */
- _SIMD32_OFFSET(pSi1) =
- ((out2) & 0xFFFF0000) | (out1 & 0x0000FFFF);
- pSi1 += 2 * n1;
-
- /* Butterfly calculations */
-
- /* Read yd (real), xd(imag) input */
- U = _SIMD32_OFFSET(pSi3);
-
- /* T = packed(yb-yd, xb-xd) */
- T = __QSUB16(T, U);
-
-#ifndef ARM_MATH_BIG_ENDIAN
-
- /* R = packed((ya-yc) + (xb- xd) , (xa-xc) - (yb-yd)) */
- R = __SHASX(S, T);
-
- /* S = packed((ya-yc) - (xb- xd), (xa-xc) + (yb-yd)) */
- S = __SHSAX(S, T);
-
-
- /* Butterfly process for the i0+fftLen/2 sample */
- out1 = __SMUAD(C1, S) >> 16U;
- out2 = __SMUSDX(C1, S);
-
-#else
-
- /* R = packed((ya-yc) + (xb- xd) , (xa-xc) - (yb-yd)) */
- R = __SHSAX(S, T);
-
- /* S = packed((ya-yc) - (xb- xd), (xa-xc) + (yb-yd)) */
- S = __SHASX(S, T);
-
-
- /* Butterfly process for the i0+fftLen/2 sample */
- out1 = __SMUSDX(S, C1) >> 16U;
- out2 = __SMUAD(C1, S);
-
-#endif /* #ifndef ARM_MATH_BIG_ENDIAN */
-
- /* xb' = (xa+yb-xc-yd)* co1 + (ya-xb-yc+xd)* (si1) */
- /* yb' = (ya-xb-yc+xd)* co1 - (xa+yb-xc-yd)* (si1) */
- _SIMD32_OFFSET(pSi2) =
- ((out2) & 0xFFFF0000) | (out1 & 0x0000FFFF);
- pSi2 += 2 * n1;
-
- /* Butterfly process for the i0+3fftLen/4 sample */
-
-#ifndef ARM_MATH_BIG_ENDIAN
-
- out1 = __SMUAD(C3, R) >> 16U;
- out2 = __SMUSDX(C3, R);
-
-#else
-
- out1 = __SMUSDX(R, C3) >> 16U;
- out2 = __SMUAD(C3, R);
-
-#endif /* #ifndef ARM_MATH_BIG_ENDIAN */
-
- /* xd' = (xa-yb-xc+yd)* co3 + (ya+xb-yc-xd)* (si3) */
- /* yd' = (ya+xb-yc-xd)* co3 - (xa-yb-xc+yd)* (si3) */
- _SIMD32_OFFSET(pSi3) =
- ((out2) & 0xFFFF0000) | (out1 & 0x0000FFFF);
- pSi3 += 2 * n1;
- }
- }
- /* Twiddle coefficients index modifier */
- twidCoefModifier <<= 2U;
- }
- /* end of middle stage process */
-
-
- /* data is in 10.6(q6) format for the 1024 point */
- /* data is in 8.8(q8) format for the 256 point */
- /* data is in 6.10(q10) format for the 64 point */
- /* data is in 4.12(q12) format for the 16 point */
-
- /* Initializations for the last stage */
- j = fftLen >> 2;
-
- ptr1 = &pSrc16[0];
-
- /* start of last stage process */
-
- /* Butterfly implementation */
- do
- {
- /* Read xa (real), ya(imag) input */
- xaya = *__SIMD32(ptr1)++;
-
- /* Read xb (real), yb(imag) input */
- xbyb = *__SIMD32(ptr1)++;
-
- /* Read xc (real), yc(imag) input */
- xcyc = *__SIMD32(ptr1)++;
-
- /* Read xd (real), yd(imag) input */
- xdyd = *__SIMD32(ptr1)++;
-
- /* R = packed((ya + yc), (xa + xc)) */
- R = __QADD16(xaya, xcyc);
-
- /* T = packed((yb + yd), (xb + xd)) */
- T = __QADD16(xbyb, xdyd);
-
- /* pointer updation for writing */
- ptr1 = ptr1 - 8U;
-
-
- /* xa' = xa + xb + xc + xd */
- /* ya' = ya + yb + yc + yd */
- *__SIMD32(ptr1)++ = __SHADD16(R, T);
-
- /* T = packed((yb + yd), (xb + xd)) */
- T = __QADD16(xbyb, xdyd);
-
- /* xc' = (xa-xb+xc-xd) */
- /* yc' = (ya-yb+yc-yd) */
- *__SIMD32(ptr1)++ = __SHSUB16(R, T);
-
- /* S = packed((ya - yc), (xa - xc)) */
- S = __QSUB16(xaya, xcyc);
-
- /* Read yd (real), xd(imag) input */
- /* T = packed( (yb - yd), (xb - xd)) */
- U = __QSUB16(xbyb, xdyd);
-
-#ifndef ARM_MATH_BIG_ENDIAN
-
- /* xb' = (xa+yb-xc-yd) */
- /* yb' = (ya-xb-yc+xd) */
- *__SIMD32(ptr1)++ = __SHSAX(S, U);
-
-
- /* xd' = (xa-yb-xc+yd) */
- /* yd' = (ya+xb-yc-xd) */
- *__SIMD32(ptr1)++ = __SHASX(S, U);
-
-#else
-
- /* xb' = (xa+yb-xc-yd) */
- /* yb' = (ya-xb-yc+xd) */
- *__SIMD32(ptr1)++ = __SHASX(S, U);
-
-
- /* xd' = (xa-yb-xc+yd) */
- /* yd' = (ya+xb-yc-xd) */
- *__SIMD32(ptr1)++ = __SHSAX(S, U);
-
-#endif /* #ifndef ARM_MATH_BIG_ENDIAN */
-
- } while (--j);
-
- /* end of last stage process */
-
- /* output is in 11.5(q5) format for the 1024 point */
- /* output is in 9.7(q7) format for the 256 point */
- /* output is in 7.9(q9) format for the 64 point */
- /* output is in 5.11(q11) format for the 16 point */
-
-
-#else
-
- /* Run the below code for Cortex-M0 */
-
- q15_t R0, R1, S0, S1, T0, T1, U0, U1;
- q15_t Co1, Si1, Co2, Si2, Co3, Si3, out1, out2;
- uint32_t n1, n2, ic, i0, i1, i2, i3, j, k;
-
- /* Total process is divided into three stages */
-
- /* process first stage, middle stages, & last stage */
-
- /* Initializations for the first stage */
- n2 = fftLen;
- n1 = n2;
-
- /* n2 = fftLen/4 */
- n2 >>= 2U;
-
- /* Index for twiddle coefficient */
- ic = 0U;
-
- /* Index for input read and output write */
- i0 = 0U;
- j = n2;
-
- /* Input is in 1.15(q15) format */
-
- /* start of first stage process */
- do
- {
- /* Butterfly implementation */
-
- /* index calculation for the input as, */
- /* pSrc16[i0 + 0], pSrc16[i0 + fftLen/4], pSrc16[i0 + fftLen/2], pSrc16[i0 + 3fftLen/4] */
- i1 = i0 + n2;
- i2 = i1 + n2;
- i3 = i2 + n2;
-
- /* Reading i0, i0+fftLen/2 inputs */
-
- /* input is down scale by 4 to avoid overflow */
- /* Read ya (real), xa(imag) input */
- T0 = pSrc16[i0 * 2U] >> 2U;
- T1 = pSrc16[(i0 * 2U) + 1U] >> 2U;
-
- /* input is down scale by 4 to avoid overflow */
- /* Read yc (real), xc(imag) input */
- S0 = pSrc16[i2 * 2U] >> 2U;
- S1 = pSrc16[(i2 * 2U) + 1U] >> 2U;
-
- /* R0 = (ya + yc) */
- R0 = __SSAT(T0 + S0, 16U);
- /* R1 = (xa + xc) */
- R1 = __SSAT(T1 + S1, 16U);
-
- /* S0 = (ya - yc) */
- S0 = __SSAT(T0 - S0, 16);
- /* S1 = (xa - xc) */
- S1 = __SSAT(T1 - S1, 16);
-
- /* Reading i0+fftLen/4 , i0+3fftLen/4 inputs */
- /* input is down scale by 4 to avoid overflow */
- /* Read yb (real), xb(imag) input */
- T0 = pSrc16[i1 * 2U] >> 2U;
- T1 = pSrc16[(i1 * 2U) + 1U] >> 2U;
-
- /* input is down scale by 4 to avoid overflow */
- /* Read yd (real), xd(imag) input */
- U0 = pSrc16[i3 * 2U] >> 2U;
- U1 = pSrc16[(i3 * 2U) + 1] >> 2U;
-
- /* T0 = (yb + yd) */
- T0 = __SSAT(T0 + U0, 16U);
- /* T1 = (xb + xd) */
- T1 = __SSAT(T1 + U1, 16U);
-
- /* writing the butterfly processed i0 sample */
- /* ya' = ya + yb + yc + yd */
- /* xa' = xa + xb + xc + xd */
- pSrc16[i0 * 2U] = (R0 >> 1U) + (T0 >> 1U);
- pSrc16[(i0 * 2U) + 1U] = (R1 >> 1U) + (T1 >> 1U);
-
- /* R0 = (ya + yc) - (yb + yd) */
- /* R1 = (xa + xc) - (xb + xd) */
- R0 = __SSAT(R0 - T0, 16U);
- R1 = __SSAT(R1 - T1, 16U);
-
- /* co2 & si2 are read from Coefficient pointer */
- Co2 = pCoef16[2U * ic * 2U];
- Si2 = pCoef16[(2U * ic * 2U) + 1];
-
- /* xc' = (xa-xb+xc-xd)* co2 + (ya-yb+yc-yd)* (si2) */
- out1 = (q15_t) ((Co2 * R0 + Si2 * R1) >> 16U);
- /* yc' = (ya-yb+yc-yd)* co2 - (xa-xb+xc-xd)* (si2) */
- out2 = (q15_t) ((-Si2 * R0 + Co2 * R1) >> 16U);
-
- /* Reading i0+fftLen/4 */
- /* input is down scale by 4 to avoid overflow */
- /* T0 = yb, T1 = xb */
- T0 = pSrc16[i1 * 2U] >> 2;
- T1 = pSrc16[(i1 * 2U) + 1] >> 2;
-
- /* writing the butterfly processed i0 + fftLen/4 sample */
- /* writing output(xc', yc') in little endian format */
- pSrc16[i1 * 2U] = out1;
- pSrc16[(i1 * 2U) + 1] = out2;
-
- /* Butterfly calculations */
- /* input is down scale by 4 to avoid overflow */
- /* U0 = yd, U1 = xd */
- U0 = pSrc16[i3 * 2U] >> 2;
- U1 = pSrc16[(i3 * 2U) + 1] >> 2;
- /* T0 = yb-yd */
- T0 = __SSAT(T0 - U0, 16);
- /* T1 = xb-xd */
- T1 = __SSAT(T1 - U1, 16);
-
- /* R1 = (ya-yc) + (xb- xd), R0 = (xa-xc) - (yb-yd)) */
- R0 = (q15_t) __SSAT((q31_t) (S0 - T1), 16);
- R1 = (q15_t) __SSAT((q31_t) (S1 + T0), 16);
-
- /* S1 = (ya-yc) - (xb- xd), S0 = (xa-xc) + (yb-yd)) */
- S0 = (q15_t) __SSAT(((q31_t) S0 + T1), 16U);
- S1 = (q15_t) __SSAT(((q31_t) S1 - T0), 16U);
-
- /* co1 & si1 are read from Coefficient pointer */
- Co1 = pCoef16[ic * 2U];
- Si1 = pCoef16[(ic * 2U) + 1];
- /* Butterfly process for the i0+fftLen/2 sample */
- /* xb' = (xa+yb-xc-yd)* co1 + (ya-xb-yc+xd)* (si1) */
- out1 = (q15_t) ((Si1 * S1 + Co1 * S0) >> 16);
- /* yb' = (ya-xb-yc+xd)* co1 - (xa+yb-xc-yd)* (si1) */
- out2 = (q15_t) ((-Si1 * S0 + Co1 * S1) >> 16);
-
- /* writing output(xb', yb') in little endian format */
- pSrc16[i2 * 2U] = out1;
- pSrc16[(i2 * 2U) + 1] = out2;
-
- /* Co3 & si3 are read from Coefficient pointer */
- Co3 = pCoef16[3U * (ic * 2U)];
- Si3 = pCoef16[(3U * (ic * 2U)) + 1];
- /* Butterfly process for the i0+3fftLen/4 sample */
- /* xd' = (xa-yb-xc+yd)* Co3 + (ya+xb-yc-xd)* (si3) */
- out1 = (q15_t) ((Si3 * R1 + Co3 * R0) >> 16U);
- /* yd' = (ya+xb-yc-xd)* Co3 - (xa-yb-xc+yd)* (si3) */
- out2 = (q15_t) ((-Si3 * R0 + Co3 * R1) >> 16U);
- /* writing output(xd', yd') in little endian format */
- pSrc16[i3 * 2U] = out1;
- pSrc16[(i3 * 2U) + 1] = out2;
-
- /* Twiddle coefficients index modifier */
- ic = ic + twidCoefModifier;
-
- /* Updating input index */
- i0 = i0 + 1U;
-
- } while (--j);
- /* data is in 4.11(q11) format */
-
- /* end of first stage process */
-
-
- /* start of middle stage process */
-
- /* Twiddle coefficients index modifier */
- twidCoefModifier <<= 2U;
-
- /* Calculation of Middle stage */
- for (k = fftLen / 4U; k > 4U; k >>= 2U)
- {
- /* Initializations for the middle stage */
- n1 = n2;
- n2 >>= 2U;
- ic = 0U;
-
- for (j = 0U; j <= (n2 - 1U); j++)
- {
- /* index calculation for the coefficients */
- Co1 = pCoef16[ic * 2U];
- Si1 = pCoef16[(ic * 2U) + 1U];
- Co2 = pCoef16[2U * (ic * 2U)];
- Si2 = pCoef16[(2U * (ic * 2U)) + 1U];
- Co3 = pCoef16[3U * (ic * 2U)];
- Si3 = pCoef16[(3U * (ic * 2U)) + 1U];
-
- /* Twiddle coefficients index modifier */
- ic = ic + twidCoefModifier;
-
- /* Butterfly implementation */
- for (i0 = j; i0 < fftLen; i0 += n1)
- {
- /* index calculation for the input as, */
- /* pSrc16[i0 + 0], pSrc16[i0 + fftLen/4], pSrc16[i0 + fftLen/2], pSrc16[i0 + 3fftLen/4] */
- i1 = i0 + n2;
- i2 = i1 + n2;
- i3 = i2 + n2;
-
- /* Reading i0, i0+fftLen/2 inputs */
- /* Read ya (real), xa(imag) input */
- T0 = pSrc16[i0 * 2U];
- T1 = pSrc16[(i0 * 2U) + 1U];
-
- /* Read yc (real), xc(imag) input */
- S0 = pSrc16[i2 * 2U];
- S1 = pSrc16[(i2 * 2U) + 1U];
-
- /* R0 = (ya + yc), R1 = (xa + xc) */
- R0 = __SSAT(T0 + S0, 16);
- R1 = __SSAT(T1 + S1, 16);
-
- /* S0 = (ya - yc), S1 =(xa - xc) */
- S0 = __SSAT(T0 - S0, 16);
- S1 = __SSAT(T1 - S1, 16);
-
- /* Reading i0+fftLen/4 , i0+3fftLen/4 inputs */
- /* Read yb (real), xb(imag) input */
- T0 = pSrc16[i1 * 2U];
- T1 = pSrc16[(i1 * 2U) + 1U];
-
- /* Read yd (real), xd(imag) input */
- U0 = pSrc16[i3 * 2U];
- U1 = pSrc16[(i3 * 2U) + 1U];
-
-
- /* T0 = (yb + yd), T1 = (xb + xd) */
- T0 = __SSAT(T0 + U0, 16);
- T1 = __SSAT(T1 + U1, 16);
-
- /* writing the butterfly processed i0 sample */
-
- /* xa' = xa + xb + xc + xd */
- /* ya' = ya + yb + yc + yd */
- out1 = ((R0 >> 1U) + (T0 >> 1U)) >> 1U;
- out2 = ((R1 >> 1U) + (T1 >> 1U)) >> 1U;
-
- pSrc16[i0 * 2U] = out1;
- pSrc16[(2U * i0) + 1U] = out2;
-
- /* R0 = (ya + yc) - (yb + yd), R1 = (xa + xc) - (xb + xd) */
- R0 = (R0 >> 1U) - (T0 >> 1U);
- R1 = (R1 >> 1U) - (T1 >> 1U);
-
- /* (ya-yb+yc-yd)* (si2) + (xa-xb+xc-xd)* co2 */
- out1 = (q15_t) ((Co2 * R0 + Si2 * R1) >> 16U);
-
- /* (ya-yb+yc-yd)* co2 - (xa-xb+xc-xd)* (si2) */
- out2 = (q15_t) ((-Si2 * R0 + Co2 * R1) >> 16U);
-
- /* Reading i0+3fftLen/4 */
- /* Read yb (real), xb(imag) input */
- T0 = pSrc16[i1 * 2U];
- T1 = pSrc16[(i1 * 2U) + 1U];
-
- /* writing the butterfly processed i0 + fftLen/4 sample */
- /* xc' = (xa-xb+xc-xd)* co2 + (ya-yb+yc-yd)* (si2) */
- /* yc' = (ya-yb+yc-yd)* co2 - (xa-xb+xc-xd)* (si2) */
- pSrc16[i1 * 2U] = out1;
- pSrc16[(i1 * 2U) + 1U] = out2;
-
- /* Butterfly calculations */
-
- /* Read yd (real), xd(imag) input */
- U0 = pSrc16[i3 * 2U];
- U1 = pSrc16[(i3 * 2U) + 1U];
-
- /* T0 = yb-yd, T1 = xb-xd */
- T0 = __SSAT(T0 - U0, 16);
- T1 = __SSAT(T1 - U1, 16);
-
- /* R0 = (ya-yc) + (xb- xd), R1 = (xa-xc) - (yb-yd)) */
- R0 = (S0 >> 1U) - (T1 >> 1U);
- R1 = (S1 >> 1U) + (T0 >> 1U);
-
- /* S0 = (ya-yc) - (xb- xd), S1 = (xa-xc) + (yb-yd)) */
- S0 = (S0 >> 1U) + (T1 >> 1U);
- S1 = (S1 >> 1U) - (T0 >> 1U);
-
- /* Butterfly process for the i0+fftLen/2 sample */
- out1 = (q15_t) ((Co1 * S0 + Si1 * S1) >> 16U);
-
- out2 = (q15_t) ((-Si1 * S0 + Co1 * S1) >> 16U);
-
- /* xb' = (xa+yb-xc-yd)* co1 + (ya-xb-yc+xd)* (si1) */
- /* yb' = (ya-xb-yc+xd)* co1 - (xa+yb-xc-yd)* (si1) */
- pSrc16[i2 * 2U] = out1;
- pSrc16[(i2 * 2U) + 1U] = out2;
-
- /* Butterfly process for the i0+3fftLen/4 sample */
- out1 = (q15_t) ((Si3 * R1 + Co3 * R0) >> 16U);
-
- out2 = (q15_t) ((-Si3 * R0 + Co3 * R1) >> 16U);
- /* xd' = (xa-yb-xc+yd)* Co3 + (ya+xb-yc-xd)* (si3) */
- /* yd' = (ya+xb-yc-xd)* Co3 - (xa-yb-xc+yd)* (si3) */
- pSrc16[i3 * 2U] = out1;
- pSrc16[(i3 * 2U) + 1U] = out2;
- }
- }
- /* Twiddle coefficients index modifier */
- twidCoefModifier <<= 2U;
- }
- /* end of middle stage process */
-
-
- /* data is in 10.6(q6) format for the 1024 point */
- /* data is in 8.8(q8) format for the 256 point */
- /* data is in 6.10(q10) format for the 64 point */
- /* data is in 4.12(q12) format for the 16 point */
-
- /* Initializations for the last stage */
- n1 = n2;
- n2 >>= 2U;
-
- /* start of last stage process */
-
- /* Butterfly implementation */
- for (i0 = 0U; i0 <= (fftLen - n1); i0 += n1)
- {
- /* index calculation for the input as, */
- /* pSrc16[i0 + 0], pSrc16[i0 + fftLen/4], pSrc16[i0 + fftLen/2], pSrc16[i0 + 3fftLen/4] */
- i1 = i0 + n2;
- i2 = i1 + n2;
- i3 = i2 + n2;
-
- /* Reading i0, i0+fftLen/2 inputs */
- /* Read ya (real), xa(imag) input */
- T0 = pSrc16[i0 * 2U];
- T1 = pSrc16[(i0 * 2U) + 1U];
-
- /* Read yc (real), xc(imag) input */
- S0 = pSrc16[i2 * 2U];
- S1 = pSrc16[(i2 * 2U) + 1U];
-
- /* R0 = (ya + yc), R1 = (xa + xc) */
- R0 = __SSAT(T0 + S0, 16U);
- R1 = __SSAT(T1 + S1, 16U);
-
- /* S0 = (ya - yc), S1 = (xa - xc) */
- S0 = __SSAT(T0 - S0, 16U);
- S1 = __SSAT(T1 - S1, 16U);
-
- /* Reading i0+fftLen/4 , i0+3fftLen/4 inputs */
- /* Read yb (real), xb(imag) input */
- T0 = pSrc16[i1 * 2U];
- T1 = pSrc16[(i1 * 2U) + 1U];
- /* Read yd (real), xd(imag) input */
- U0 = pSrc16[i3 * 2U];
- U1 = pSrc16[(i3 * 2U) + 1U];
-
- /* T0 = (yb + yd), T1 = (xb + xd)) */
- T0 = __SSAT(T0 + U0, 16U);
- T1 = __SSAT(T1 + U1, 16U);
-
- /* writing the butterfly processed i0 sample */
- /* xa' = xa + xb + xc + xd */
- /* ya' = ya + yb + yc + yd */
- pSrc16[i0 * 2U] = (R0 >> 1U) + (T0 >> 1U);
- pSrc16[(i0 * 2U) + 1U] = (R1 >> 1U) + (T1 >> 1U);
-
- /* R0 = (ya + yc) - (yb + yd), R1 = (xa + xc) - (xb + xd) */
- R0 = (R0 >> 1U) - (T0 >> 1U);
- R1 = (R1 >> 1U) - (T1 >> 1U);
- /* Read yb (real), xb(imag) input */
- T0 = pSrc16[i1 * 2U];
- T1 = pSrc16[(i1 * 2U) + 1U];
-
- /* writing the butterfly processed i0 + fftLen/4 sample */
- /* xc' = (xa-xb+xc-xd) */
- /* yc' = (ya-yb+yc-yd) */
- pSrc16[i1 * 2U] = R0;
- pSrc16[(i1 * 2U) + 1U] = R1;
-
- /* Read yd (real), xd(imag) input */
- U0 = pSrc16[i3 * 2U];
- U1 = pSrc16[(i3 * 2U) + 1U];
- /* T0 = (yb - yd), T1 = (xb - xd) */
- T0 = __SSAT(T0 - U0, 16U);
- T1 = __SSAT(T1 - U1, 16U);
-
- /* writing the butterfly processed i0 + fftLen/2 sample */
- /* xb' = (xa+yb-xc-yd) */
- /* yb' = (ya-xb-yc+xd) */
- pSrc16[i2 * 2U] = (S0 >> 1U) + (T1 >> 1U);
- pSrc16[(i2 * 2U) + 1U] = (S1 >> 1U) - (T0 >> 1U);
-
- /* writing the butterfly processed i0 + 3fftLen/4 sample */
- /* xd' = (xa-yb-xc+yd) */
- /* yd' = (ya+xb-yc-xd) */
- pSrc16[i3 * 2U] = (S0 >> 1U) - (T1 >> 1U);
- pSrc16[(i3 * 2U) + 1U] = (S1 >> 1U) + (T0 >> 1U);
-
- }
-
- /* end of last stage process */
-
- /* output is in 11.5(q5) format for the 1024 point */
- /* output is in 9.7(q7) format for the 256 point */
- /* output is in 7.9(q9) format for the 64 point */
- /* output is in 5.11(q11) format for the 16 point */
-
-#endif /* #if defined (ARM_MATH_DSP) */
-
-}
-
-
-/**
- * @brief Core function for the Q15 CIFFT butterfly process.
- * @param[in, out] *pSrc16 points to the in-place buffer of Q15 data type.
- * @param[in] fftLen length of the FFT.
- * @param[in] *pCoef16 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_q15(
- q15_t * pSrc16,
- uint32_t fftLen,
- q15_t * pCoef16,
- uint32_t twidCoefModifier)
-{
-
-#if defined (ARM_MATH_DSP)
-
- /* Run the below code for Cortex-M4 and Cortex-M3 */
-
- q31_t R, S, T, U;
- q31_t C1, C2, C3, out1, out2;
- uint32_t n1, n2, ic, i0, j, k;
-
- q15_t *ptr1;
- q15_t *pSi0;
- q15_t *pSi1;
- q15_t *pSi2;
- q15_t *pSi3;
-
- q31_t xaya, xbyb, xcyc, xdyd;
-
- /* Total process is divided into three stages */
-
- /* process first stage, middle stages, & last stage */
-
- /* Initializations for the first stage */
- n2 = fftLen;
- n1 = n2;
-
- /* n2 = fftLen/4 */
- n2 >>= 2U;
-
- /* Index for twiddle coefficient */
- ic = 0U;
-
- /* Index for input read and output write */
- j = n2;
-
- pSi0 = pSrc16;
- pSi1 = pSi0 + 2 * n2;
- pSi2 = pSi1 + 2 * n2;
- pSi3 = pSi2 + 2 * n2;
-
- /* Input is in 1.15(q15) format */
-
- /* start of first stage process */
- do
- {
- /* Butterfly implementation */
-
- /* Reading i0, i0+fftLen/2 inputs */
- /* Read ya (real), xa(imag) input */
- T = _SIMD32_OFFSET(pSi0);
- T = __SHADD16(T, 0);
- T = __SHADD16(T, 0);
-
- /* Read yc (real), xc(imag) input */
- S = _SIMD32_OFFSET(pSi2);
- S = __SHADD16(S, 0);
- S = __SHADD16(S, 0);
-
- /* R = packed((ya + yc), (xa + xc) ) */
- R = __QADD16(T, S);
-
- /* S = packed((ya - yc), (xa - xc) ) */
- S = __QSUB16(T, S);
-
- /* Reading i0+fftLen/4 , i0+3fftLen/4 inputs */
- /* Read yb (real), xb(imag) input */
- T = _SIMD32_OFFSET(pSi1);
- T = __SHADD16(T, 0);
- T = __SHADD16(T, 0);
-
- /* Read yd (real), xd(imag) input */
- U = _SIMD32_OFFSET(pSi3);
- U = __SHADD16(U, 0);
- U = __SHADD16(U, 0);
-
- /* T = packed((yb + yd), (xb + xd) ) */
- T = __QADD16(T, U);
-
- /* writing the butterfly processed i0 sample */
- /* xa' = xa + xb + xc + xd */
- /* ya' = ya + yb + yc + yd */
- _SIMD32_OFFSET(pSi0) = __SHADD16(R, T);
- pSi0 += 2;
-
- /* R = packed((ya + yc) - (yb + yd), (xa + xc)- (xb + xd)) */
- R = __QSUB16(R, T);
-
- /* co2 & si2 are read from SIMD Coefficient pointer */
- C2 = _SIMD32_OFFSET(pCoef16 + (4U * ic));
-
-#ifndef ARM_MATH_BIG_ENDIAN
-
- /* xc' = (xa-xb+xc-xd)* co2 + (ya-yb+yc-yd)* (si2) */
- out1 = __SMUSD(C2, R) >> 16U;
- /* yc' = (ya-yb+yc-yd)* co2 - (xa-xb+xc-xd)* (si2) */
- out2 = __SMUADX(C2, R);
-
-#else
-
- /* xc' = (ya-yb+yc-yd)* co2 - (xa-xb+xc-xd)* (si2) */
- out1 = __SMUADX(C2, R) >> 16U;
- /* yc' = (xa-xb+xc-xd)* co2 + (ya-yb+yc-yd)* (si2) */
- out2 = __SMUSD(__QSUB16(0, C2), R);
-
-#endif /* #ifndef ARM_MATH_BIG_ENDIAN */
-
- /* Reading i0+fftLen/4 */
- /* T = packed(yb, xb) */
- T = _SIMD32_OFFSET(pSi1);
- T = __SHADD16(T, 0);
- T = __SHADD16(T, 0);
-
- /* writing the butterfly processed i0 + fftLen/4 sample */
- /* writing output(xc', yc') in little endian format */
- _SIMD32_OFFSET(pSi1) =
- (q31_t) ((out2) & 0xFFFF0000) | (out1 & 0x0000FFFF);
- pSi1 += 2;
-
- /* Butterfly calculations */
- /* U = packed(yd, xd) */
- U = _SIMD32_OFFSET(pSi3);
- U = __SHADD16(U, 0);
- U = __SHADD16(U, 0);
-
- /* T = packed(yb-yd, xb-xd) */
- T = __QSUB16(T, U);
-
-#ifndef ARM_MATH_BIG_ENDIAN
-
- /* R = packed((ya-yc) + (xb- xd) , (xa-xc) - (yb-yd)) */
- R = __QSAX(S, T);
- /* S = packed((ya-yc) + (xb- xd), (xa-xc) - (yb-yd)) */
- S = __QASX(S, T);
-
-#else
-
- /* R = packed((ya-yc) + (xb- xd) , (xa-xc) - (yb-yd)) */
- R = __QASX(S, T);
- /* S = packed((ya-yc) - (xb- xd), (xa-xc) + (yb-yd)) */
- S = __QSAX(S, T);
-
-#endif /* #ifndef ARM_MATH_BIG_ENDIAN */
-
- /* co1 & si1 are read from SIMD Coefficient pointer */
- C1 = _SIMD32_OFFSET(pCoef16 + (2U * ic));
- /* Butterfly process for the i0+fftLen/2 sample */
-
-#ifndef ARM_MATH_BIG_ENDIAN
-
- /* xb' = (xa+yb-xc-yd)* co1 + (ya-xb-yc+xd)* (si1) */
- out1 = __SMUSD(C1, S) >> 16U;
- /* yb' = (ya-xb-yc+xd)* co1 - (xa+yb-xc-yd)* (si1) */
- out2 = __SMUADX(C1, S);
-
-#else
-
- /* xb' = (ya-xb-yc+xd)* co1 - (xa+yb-xc-yd)* (si1) */
- out1 = __SMUADX(C1, S) >> 16U;
- /* yb' = (xa+yb-xc-yd)* co1 + (ya-xb-yc+xd)* (si1) */
- out2 = __SMUSD(__QSUB16(0, C1), S);
-
-#endif /* #ifndef ARM_MATH_BIG_ENDIAN */
-
- /* writing output(xb', yb') in little endian format */
- _SIMD32_OFFSET(pSi2) =
- ((out2) & 0xFFFF0000) | ((out1) & 0x0000FFFF);
- pSi2 += 2;
-
-
- /* co3 & si3 are read from SIMD Coefficient pointer */
- C3 = _SIMD32_OFFSET(pCoef16 + (6U * ic));
- /* Butterfly process for the i0+3fftLen/4 sample */
-
-#ifndef ARM_MATH_BIG_ENDIAN
-
- /* xd' = (xa-yb-xc+yd)* co3 + (ya+xb-yc-xd)* (si3) */
- out1 = __SMUSD(C3, R) >> 16U;
- /* yd' = (ya+xb-yc-xd)* co3 - (xa-yb-xc+yd)* (si3) */
- out2 = __SMUADX(C3, R);
-
-#else
-
- /* xd' = (ya+xb-yc-xd)* co3 - (xa-yb-xc+yd)* (si3) */
- out1 = __SMUADX(C3, R) >> 16U;
- /* yd' = (xa-yb-xc+yd)* co3 + (ya+xb-yc-xd)* (si3) */
- out2 = __SMUSD(__QSUB16(0, C3), R);
-
-#endif /* #ifndef ARM_MATH_BIG_ENDIAN */
-
- /* writing output(xd', yd') in little endian format */
- _SIMD32_OFFSET(pSi3) =
- ((out2) & 0xFFFF0000) | (out1 & 0x0000FFFF);
- pSi3 += 2;
-
- /* Twiddle coefficients index modifier */
- ic = ic + twidCoefModifier;
-
- } while (--j);
- /* data is in 4.11(q11) format */
-
- /* end of first stage process */
-
-
- /* start of middle stage process */
-
- /* Twiddle coefficients index modifier */
- twidCoefModifier <<= 2U;
-
- /* Calculation of Middle stage */
- for (k = fftLen / 4U; k > 4U; k >>= 2U)
- {
- /* Initializations for the middle stage */
- n1 = n2;
- n2 >>= 2U;
- ic = 0U;
-
- for (j = 0U; j <= (n2 - 1U); j++)
- {
- /* index calculation for the coefficients */
- C1 = _SIMD32_OFFSET(pCoef16 + (2U * ic));
- C2 = _SIMD32_OFFSET(pCoef16 + (4U * ic));
- C3 = _SIMD32_OFFSET(pCoef16 + (6U * ic));
-
- /* Twiddle coefficients index modifier */
- ic = ic + twidCoefModifier;
-
- pSi0 = pSrc16 + 2 * j;
- pSi1 = pSi0 + 2 * n2;
- pSi2 = pSi1 + 2 * n2;
- pSi3 = pSi2 + 2 * n2;
-
- /* Butterfly implementation */
- for (i0 = j; i0 < fftLen; i0 += n1)
- {
- /* Reading i0, i0+fftLen/2 inputs */
- /* Read ya (real), xa(imag) input */
- T = _SIMD32_OFFSET(pSi0);
-
- /* Read yc (real), xc(imag) input */
- S = _SIMD32_OFFSET(pSi2);
-
- /* R = packed( (ya + yc), (xa + xc)) */
- R = __QADD16(T, S);
-
- /* S = packed((ya - yc), (xa - xc)) */
- S = __QSUB16(T, S);
-
- /* Reading i0+fftLen/4 , i0+3fftLen/4 inputs */
- /* Read yb (real), xb(imag) input */
- T = _SIMD32_OFFSET(pSi1);
-
- /* Read yd (real), xd(imag) input */
- U = _SIMD32_OFFSET(pSi3);
-
- /* T = packed( (yb + yd), (xb + xd)) */
- T = __QADD16(T, U);
-
- /* writing the butterfly processed i0 sample */
-
- /* xa' = xa + xb + xc + xd */
- /* ya' = ya + yb + yc + yd */
- out1 = __SHADD16(R, T);
- out1 = __SHADD16(out1, 0);
- _SIMD32_OFFSET(pSi0) = out1;
- pSi0 += 2 * n1;
-
- /* R = packed( (ya + yc) - (yb + yd), (xa + xc) - (xb + xd)) */
- R = __SHSUB16(R, T);
-
-#ifndef ARM_MATH_BIG_ENDIAN
-
- /* (ya-yb+yc-yd)* (si2) + (xa-xb+xc-xd)* co2 */
- out1 = __SMUSD(C2, R) >> 16U;
-
- /* (ya-yb+yc-yd)* co2 - (xa-xb+xc-xd)* (si2) */
- out2 = __SMUADX(C2, R);
-
-#else
-
- /* (ya-yb+yc-yd)* co2 - (xa-xb+xc-xd)* (si2) */
- out1 = __SMUADX(R, C2) >> 16U;
-
- /* (ya-yb+yc-yd)* (si2) + (xa-xb+xc-xd)* co2 */
- out2 = __SMUSD(__QSUB16(0, C2), R);
-
-#endif /* #ifndef ARM_MATH_BIG_ENDIAN */
-
- /* Reading i0+3fftLen/4 */
- /* Read yb (real), xb(imag) input */
- T = _SIMD32_OFFSET(pSi1);
-
- /* writing the butterfly processed i0 + fftLen/4 sample */
- /* xc' = (xa-xb+xc-xd)* co2 + (ya-yb+yc-yd)* (si2) */
- /* yc' = (ya-yb+yc-yd)* co2 - (xa-xb+xc-xd)* (si2) */
- _SIMD32_OFFSET(pSi1) =
- ((out2) & 0xFFFF0000) | (out1 & 0x0000FFFF);
- pSi1 += 2 * n1;
-
- /* Butterfly calculations */
-
- /* Read yd (real), xd(imag) input */
- U = _SIMD32_OFFSET(pSi3);
-
- /* T = packed(yb-yd, xb-xd) */
- T = __QSUB16(T, U);
-
-#ifndef ARM_MATH_BIG_ENDIAN
-
- /* R = packed((ya-yc) + (xb- xd) , (xa-xc) - (yb-yd)) */
- R = __SHSAX(S, T);
-
- /* S = packed((ya-yc) - (xb- xd), (xa-xc) + (yb-yd)) */
- S = __SHASX(S, T);
-
-
- /* Butterfly process for the i0+fftLen/2 sample */
- out1 = __SMUSD(C1, S) >> 16U;
- out2 = __SMUADX(C1, S);
-
-#else
-
- /* R = packed((ya-yc) + (xb- xd) , (xa-xc) - (yb-yd)) */
- R = __SHASX(S, T);
-
- /* S = packed((ya-yc) - (xb- xd), (xa-xc) + (yb-yd)) */
- S = __SHSAX(S, T);
-
-
- /* Butterfly process for the i0+fftLen/2 sample */
- out1 = __SMUADX(S, C1) >> 16U;
- out2 = __SMUSD(__QSUB16(0, C1), S);
-
-#endif /* #ifndef ARM_MATH_BIG_ENDIAN */
-
- /* xb' = (xa+yb-xc-yd)* co1 + (ya-xb-yc+xd)* (si1) */
- /* yb' = (ya-xb-yc+xd)* co1 - (xa+yb-xc-yd)* (si1) */
- _SIMD32_OFFSET(pSi2) =
- ((out2) & 0xFFFF0000) | (out1 & 0x0000FFFF);
- pSi2 += 2 * n1;
-
- /* Butterfly process for the i0+3fftLen/4 sample */
-
-#ifndef ARM_MATH_BIG_ENDIAN
-
- out1 = __SMUSD(C3, R) >> 16U;
- out2 = __SMUADX(C3, R);
-
-#else
-
- out1 = __SMUADX(C3, R) >> 16U;
- out2 = __SMUSD(__QSUB16(0, C3), R);
-
-#endif /* #ifndef ARM_MATH_BIG_ENDIAN */
-
- /* xd' = (xa-yb-xc+yd)* co3 + (ya+xb-yc-xd)* (si3) */
- /* yd' = (ya+xb-yc-xd)* co3 - (xa-yb-xc+yd)* (si3) */
- _SIMD32_OFFSET(pSi3) =
- ((out2) & 0xFFFF0000) | (out1 & 0x0000FFFF);
- pSi3 += 2 * n1;
- }
- }
- /* Twiddle coefficients index modifier */
- twidCoefModifier <<= 2U;
- }
- /* end of middle stage process */
-
- /* data is in 10.6(q6) format for the 1024 point */
- /* data is in 8.8(q8) format for the 256 point */
- /* data is in 6.10(q10) format for the 64 point */
- /* data is in 4.12(q12) format for the 16 point */
-
- /* Initializations for the last stage */
- j = fftLen >> 2;
-
- ptr1 = &pSrc16[0];
-
- /* start of last stage process */
-
- /* Butterfly implementation */
- do
- {
- /* Read xa (real), ya(imag) input */
- xaya = *__SIMD32(ptr1)++;
-
- /* Read xb (real), yb(imag) input */
- xbyb = *__SIMD32(ptr1)++;
-
- /* Read xc (real), yc(imag) input */
- xcyc = *__SIMD32(ptr1)++;
-
- /* Read xd (real), yd(imag) input */
- xdyd = *__SIMD32(ptr1)++;
-
- /* R = packed((ya + yc), (xa + xc)) */
- R = __QADD16(xaya, xcyc);
-
- /* T = packed((yb + yd), (xb + xd)) */
- T = __QADD16(xbyb, xdyd);
-
- /* pointer updation for writing */
- ptr1 = ptr1 - 8U;
-
-
- /* xa' = xa + xb + xc + xd */
- /* ya' = ya + yb + yc + yd */
- *__SIMD32(ptr1)++ = __SHADD16(R, T);
-
- /* T = packed((yb + yd), (xb + xd)) */
- T = __QADD16(xbyb, xdyd);
-
- /* xc' = (xa-xb+xc-xd) */
- /* yc' = (ya-yb+yc-yd) */
- *__SIMD32(ptr1)++ = __SHSUB16(R, T);
-
- /* S = packed((ya - yc), (xa - xc)) */
- S = __QSUB16(xaya, xcyc);
-
- /* Read yd (real), xd(imag) input */
- /* T = packed( (yb - yd), (xb - xd)) */
- U = __QSUB16(xbyb, xdyd);
-
-#ifndef ARM_MATH_BIG_ENDIAN
-
- /* xb' = (xa+yb-xc-yd) */
- /* yb' = (ya-xb-yc+xd) */
- *__SIMD32(ptr1)++ = __SHASX(S, U);
-
-
- /* xd' = (xa-yb-xc+yd) */
- /* yd' = (ya+xb-yc-xd) */
- *__SIMD32(ptr1)++ = __SHSAX(S, U);
-
-#else
-
- /* xb' = (xa+yb-xc-yd) */
- /* yb' = (ya-xb-yc+xd) */
- *__SIMD32(ptr1)++ = __SHSAX(S, U);
-
-
- /* xd' = (xa-yb-xc+yd) */
- /* yd' = (ya+xb-yc-xd) */
- *__SIMD32(ptr1)++ = __SHASX(S, U);
-
-
-#endif /* #ifndef ARM_MATH_BIG_ENDIAN */
-
- } while (--j);
-
- /* end of last stage process */
-
- /* output is in 11.5(q5) format for the 1024 point */
- /* output is in 9.7(q7) format for the 256 point */
- /* output is in 7.9(q9) format for the 64 point */
- /* output is in 5.11(q11) format for the 16 point */
-
-
-#else
-
- /* Run the below code for Cortex-M0 */
-
- q15_t R0, R1, S0, S1, T0, T1, U0, U1;
- q15_t Co1, Si1, Co2, Si2, Co3, Si3, out1, out2;
- uint32_t n1, n2, ic, i0, i1, i2, i3, j, k;
-
- /* Total process is divided into three stages */
-
- /* process first stage, middle stages, & last stage */
-
- /* Initializations for the first stage */
- n2 = fftLen;
- n1 = n2;
-
- /* n2 = fftLen/4 */
- n2 >>= 2U;
-
- /* Index for twiddle coefficient */
- ic = 0U;
-
- /* Index for input read and output write */
- i0 = 0U;
-
- j = n2;
-
- /* Input is in 1.15(q15) format */
-
- /* Start of first stage process */
- do
- {
- /* Butterfly implementation */
-
- /* index calculation for the input as, */
- /* pSrc16[i0 + 0], pSrc16[i0 + fftLen/4], pSrc16[i0 + fftLen/2], pSrc16[i0 + 3fftLen/4] */
- i1 = i0 + n2;
- i2 = i1 + n2;
- i3 = i2 + n2;
-
- /* Reading i0, i0+fftLen/2 inputs */
- /* input is down scale by 4 to avoid overflow */
- /* Read ya (real), xa(imag) input */
- T0 = pSrc16[i0 * 2U] >> 2U;
- T1 = pSrc16[(i0 * 2U) + 1U] >> 2U;
- /* input is down scale by 4 to avoid overflow */
- /* Read yc (real), xc(imag) input */
- S0 = pSrc16[i2 * 2U] >> 2U;
- S1 = pSrc16[(i2 * 2U) + 1U] >> 2U;
-
- /* R0 = (ya + yc), R1 = (xa + xc) */
- R0 = __SSAT(T0 + S0, 16U);
- R1 = __SSAT(T1 + S1, 16U);
- /* S0 = (ya - yc), S1 = (xa - xc) */
- S0 = __SSAT(T0 - S0, 16U);
- S1 = __SSAT(T1 - S1, 16U);
-
- /* Reading i0+fftLen/4 , i0+3fftLen/4 inputs */
- /* input is down scale by 4 to avoid overflow */
- /* Read yb (real), xb(imag) input */
- T0 = pSrc16[i1 * 2U] >> 2U;
- T1 = pSrc16[(i1 * 2U) + 1U] >> 2U;
- /* Read yd (real), xd(imag) input */
- /* input is down scale by 4 to avoid overflow */
- U0 = pSrc16[i3 * 2U] >> 2U;
- U1 = pSrc16[(i3 * 2U) + 1U] >> 2U;
-
- /* T0 = (yb + yd), T1 = (xb + xd) */
- T0 = __SSAT(T0 + U0, 16U);
- T1 = __SSAT(T1 + U1, 16U);
-
- /* writing the butterfly processed i0 sample */
- /* xa' = xa + xb + xc + xd */
- /* ya' = ya + yb + yc + yd */
- pSrc16[i0 * 2U] = (R0 >> 1U) + (T0 >> 1U);
- pSrc16[(i0 * 2U) + 1U] = (R1 >> 1U) + (T1 >> 1U);
-
- /* R0 = (ya + yc) - (yb + yd), R1 = (xa + xc)- (xb + xd) */
- R0 = __SSAT(R0 - T0, 16U);
- R1 = __SSAT(R1 - T1, 16U);
- /* co2 & si2 are read from Coefficient pointer */
- Co2 = pCoef16[2U * ic * 2U];
- Si2 = pCoef16[(2U * ic * 2U) + 1U];
- /* xc' = (xa-xb+xc-xd)* co2 - (ya-yb+yc-yd)* (si2) */
- out1 = (q15_t) ((Co2 * R0 - Si2 * R1) >> 16U);
- /* yc' = (ya-yb+yc-yd)* co2 + (xa-xb+xc-xd)* (si2) */
- out2 = (q15_t) ((Si2 * R0 + Co2 * R1) >> 16U);
-
- /* Reading i0+fftLen/4 */
- /* input is down scale by 4 to avoid overflow */
- /* T0 = yb, T1 = xb */
- T0 = pSrc16[i1 * 2U] >> 2U;
- T1 = pSrc16[(i1 * 2U) + 1U] >> 2U;
-
- /* writing the butterfly processed i0 + fftLen/4 sample */
- /* writing output(xc', yc') in little endian format */
- pSrc16[i1 * 2U] = out1;
- pSrc16[(i1 * 2U) + 1U] = out2;
-
- /* Butterfly calculations */
- /* input is down scale by 4 to avoid overflow */
- /* U0 = yd, U1 = xd) */
- U0 = pSrc16[i3 * 2U] >> 2U;
- U1 = pSrc16[(i3 * 2U) + 1U] >> 2U;
-
- /* T0 = yb-yd, T1 = xb-xd) */
- T0 = __SSAT(T0 - U0, 16U);
- T1 = __SSAT(T1 - U1, 16U);
- /* R0 = (ya-yc) - (xb- xd) , R1 = (xa-xc) + (yb-yd) */
- R0 = (q15_t) __SSAT((q31_t) (S0 + T1), 16);
- R1 = (q15_t) __SSAT((q31_t) (S1 - T0), 16);
- /* S = (ya-yc) + (xb- xd), S1 = (xa-xc) - (yb-yd) */
- S0 = (q15_t) __SSAT((q31_t) (S0 - T1), 16);
- S1 = (q15_t) __SSAT((q31_t) (S1 + T0), 16);
-
- /* co1 & si1 are read from Coefficient pointer */
- Co1 = pCoef16[ic * 2U];
- Si1 = pCoef16[(ic * 2U) + 1U];
- /* Butterfly process for the i0+fftLen/2 sample */
- /* xb' = (xa-yb-xc+yd)* co1 - (ya+xb-yc-xd)* (si1) */
- out1 = (q15_t) ((Co1 * S0 - Si1 * S1) >> 16U);
- /* yb' = (ya+xb-yc-xd)* co1 + (xa-yb-xc+yd)* (si1) */
- out2 = (q15_t) ((Si1 * S0 + Co1 * S1) >> 16U);
- /* writing output(xb', yb') in little endian format */
- pSrc16[i2 * 2U] = out1;
- pSrc16[(i2 * 2U) + 1U] = out2;
-
- /* Co3 & si3 are read from Coefficient pointer */
- Co3 = pCoef16[3U * ic * 2U];
- Si3 = pCoef16[(3U * ic * 2U) + 1U];
- /* Butterfly process for the i0+3fftLen/4 sample */
- /* xd' = (xa+yb-xc-yd)* Co3 - (ya-xb-yc+xd)* (si3) */
- out1 = (q15_t) ((Co3 * R0 - Si3 * R1) >> 16U);
- /* yd' = (ya-xb-yc+xd)* Co3 + (xa+yb-xc-yd)* (si3) */
- out2 = (q15_t) ((Si3 * R0 + Co3 * R1) >> 16U);
- /* writing output(xd', yd') in little endian format */
- pSrc16[i3 * 2U] = out1;
- pSrc16[(i3 * 2U) + 1U] = out2;
-
- /* Twiddle coefficients index modifier */
- ic = ic + twidCoefModifier;
-
- /* Updating input index */
- i0 = i0 + 1U;
-
- } while (--j);
-
- /* End of first stage process */
-
- /* data is in 4.11(q11) format */
-
-
- /* Start of Middle stage process */
-
- /* Twiddle coefficients index modifier */
- twidCoefModifier <<= 2U;
-
- /* Calculation of Middle stage */
- for (k = fftLen / 4U; k > 4U; k >>= 2U)
- {
- /* Initializations for the middle stage */
- n1 = n2;
- n2 >>= 2U;
- ic = 0U;
-
- for (j = 0U; j <= (n2 - 1U); j++)
- {
- /* index calculation for the coefficients */
- Co1 = pCoef16[ic * 2U];
- Si1 = pCoef16[(ic * 2U) + 1U];
- Co2 = pCoef16[2U * ic * 2U];
- Si2 = pCoef16[2U * ic * 2U + 1U];
- Co3 = pCoef16[3U * ic * 2U];
- Si3 = pCoef16[(3U * ic * 2U) + 1U];
-
- /* Twiddle coefficients index modifier */
- ic = ic + twidCoefModifier;
-
- /* Butterfly implementation */
- for (i0 = j; i0 < fftLen; i0 += n1)
- {
- /* index calculation for the input as, */
- /* pSrc16[i0 + 0], pSrc16[i0 + fftLen/4], pSrc16[i0 + fftLen/2], pSrc16[i0 + 3fftLen/4] */
- i1 = i0 + n2;
- i2 = i1 + n2;
- i3 = i2 + n2;
-
- /* Reading i0, i0+fftLen/2 inputs */
- /* Read ya (real), xa(imag) input */
- T0 = pSrc16[i0 * 2U];
- T1 = pSrc16[(i0 * 2U) + 1U];
-
- /* Read yc (real), xc(imag) input */
- S0 = pSrc16[i2 * 2U];
- S1 = pSrc16[(i2 * 2U) + 1U];
-
-
- /* R0 = (ya + yc), R1 = (xa + xc) */
- R0 = __SSAT(T0 + S0, 16U);
- R1 = __SSAT(T1 + S1, 16U);
- /* S0 = (ya - yc), S1 = (xa - xc) */
- S0 = __SSAT(T0 - S0, 16U);
- S1 = __SSAT(T1 - S1, 16U);
-
- /* Reading i0+fftLen/4 , i0+3fftLen/4 inputs */
- /* Read yb (real), xb(imag) input */
- T0 = pSrc16[i1 * 2U];
- T1 = pSrc16[(i1 * 2U) + 1U];
-
- /* Read yd (real), xd(imag) input */
- U0 = pSrc16[i3 * 2U];
- U1 = pSrc16[(i3 * 2U) + 1U];
-
- /* T0 = (yb + yd), T1 = (xb + xd) */
- T0 = __SSAT(T0 + U0, 16U);
- T1 = __SSAT(T1 + U1, 16U);
-
- /* writing the butterfly processed i0 sample */
- /* xa' = xa + xb + xc + xd */
- /* ya' = ya + yb + yc + yd */
- pSrc16[i0 * 2U] = ((R0 >> 1U) + (T0 >> 1U)) >> 1U;
- pSrc16[(i0 * 2U) + 1U] = ((R1 >> 1U) + (T1 >> 1U)) >> 1U;
-
- /* R0 = (ya + yc) - (yb + yd), R1 = (xa + xc) - (xb + xd) */
- R0 = (R0 >> 1U) - (T0 >> 1U);
- R1 = (R1 >> 1U) - (T1 >> 1U);
-
- /* (ya-yb+yc-yd)* (si2) - (xa-xb+xc-xd)* co2 */
- out1 = (q15_t) ((Co2 * R0 - Si2 * R1) >> 16);
- /* (ya-yb+yc-yd)* co2 + (xa-xb+xc-xd)* (si2) */
- out2 = (q15_t) ((Si2 * R0 + Co2 * R1) >> 16);
-
- /* Reading i0+3fftLen/4 */
- /* Read yb (real), xb(imag) input */
- T0 = pSrc16[i1 * 2U];
- T1 = pSrc16[(i1 * 2U) + 1U];
-
- /* writing the butterfly processed i0 + fftLen/4 sample */
- /* xc' = (xa-xb+xc-xd)* co2 - (ya-yb+yc-yd)* (si2) */
- /* yc' = (ya-yb+yc-yd)* co2 + (xa-xb+xc-xd)* (si2) */
- pSrc16[i1 * 2U] = out1;
- pSrc16[(i1 * 2U) + 1U] = out2;
-
- /* Butterfly calculations */
- /* Read yd (real), xd(imag) input */
- U0 = pSrc16[i3 * 2U];
- U1 = pSrc16[(i3 * 2U) + 1U];
-
- /* T0 = yb-yd, T1 = xb-xd) */
- T0 = __SSAT(T0 - U0, 16U);
- T1 = __SSAT(T1 - U1, 16U);
-
- /* R0 = (ya-yc) - (xb- xd) , R1 = (xa-xc) + (yb-yd) */
- R0 = (S0 >> 1U) + (T1 >> 1U);
- R1 = (S1 >> 1U) - (T0 >> 1U);
-
- /* S1 = (ya-yc) + (xb- xd), S1 = (xa-xc) - (yb-yd) */
- S0 = (S0 >> 1U) - (T1 >> 1U);
- S1 = (S1 >> 1U) + (T0 >> 1U);
-
- /* Butterfly process for the i0+fftLen/2 sample */
- out1 = (q15_t) ((Co1 * S0 - Si1 * S1) >> 16U);
- out2 = (q15_t) ((Si1 * S0 + Co1 * S1) >> 16U);
- /* xb' = (xa-yb-xc+yd)* co1 - (ya+xb-yc-xd)* (si1) */
- /* yb' = (ya+xb-yc-xd)* co1 + (xa-yb-xc+yd)* (si1) */
- pSrc16[i2 * 2U] = out1;
- pSrc16[(i2 * 2U) + 1U] = out2;
-
- /* Butterfly process for the i0+3fftLen/4 sample */
- out1 = (q15_t) ((Co3 * R0 - Si3 * R1) >> 16U);
-
- out2 = (q15_t) ((Si3 * R0 + Co3 * R1) >> 16U);
- /* xd' = (xa+yb-xc-yd)* Co3 - (ya-xb-yc+xd)* (si3) */
- /* yd' = (ya-xb-yc+xd)* Co3 + (xa+yb-xc-yd)* (si3) */
- pSrc16[i3 * 2U] = out1;
- pSrc16[(i3 * 2U) + 1U] = out2;
-
-
- }
- }
- /* Twiddle coefficients index modifier */
- twidCoefModifier <<= 2U;
- }
- /* End of Middle stages process */
-
-
- /* data is in 10.6(q6) format for the 1024 point */
- /* data is in 8.8(q8) format for the 256 point */
- /* data is in 6.10(q10) format for the 64 point */
- /* data is in 4.12(q12) format for the 16 point */
-
- /* start of last stage process */
-
-
- /* Initializations for the last stage */
- n1 = n2;
- n2 >>= 2U;
-
- /* Butterfly implementation */
- for (i0 = 0U; i0 <= (fftLen - n1); i0 += n1)
- {
- /* index calculation for the input as, */
- /* pSrc16[i0 + 0], pSrc16[i0 + fftLen/4], pSrc16[i0 + fftLen/2], pSrc16[i0 + 3fftLen/4] */
- i1 = i0 + n2;
- i2 = i1 + n2;
- i3 = i2 + n2;
-
- /* Reading i0, i0+fftLen/2 inputs */
- /* Read ya (real), xa(imag) input */
- T0 = pSrc16[i0 * 2U];
- T1 = pSrc16[(i0 * 2U) + 1U];
- /* Read yc (real), xc(imag) input */
- S0 = pSrc16[i2 * 2U];
- S1 = pSrc16[(i2 * 2U) + 1U];
-
- /* R0 = (ya + yc), R1 = (xa + xc) */
- R0 = __SSAT(T0 + S0, 16U);
- R1 = __SSAT(T1 + S1, 16U);
- /* S0 = (ya - yc), S1 = (xa - xc) */
- S0 = __SSAT(T0 - S0, 16U);
- S1 = __SSAT(T1 - S1, 16U);
-
- /* Reading i0+fftLen/4 , i0+3fftLen/4 inputs */
- /* Read yb (real), xb(imag) input */
- T0 = pSrc16[i1 * 2U];
- T1 = pSrc16[(i1 * 2U) + 1U];
- /* Read yd (real), xd(imag) input */
- U0 = pSrc16[i3 * 2U];
- U1 = pSrc16[(i3 * 2U) + 1U];
-
- /* T0 = (yb + yd), T1 = (xb + xd) */
- T0 = __SSAT(T0 + U0, 16U);
- T1 = __SSAT(T1 + U1, 16U);
-
- /* writing the butterfly processed i0 sample */
- /* xa' = xa + xb + xc + xd */
- /* ya' = ya + yb + yc + yd */
- pSrc16[i0 * 2U] = (R0 >> 1U) + (T0 >> 1U);
- pSrc16[(i0 * 2U) + 1U] = (R1 >> 1U) + (T1 >> 1U);
-
- /* R0 = (ya + yc) - (yb + yd), R1 = (xa + xc) - (xb + xd) */
- R0 = (R0 >> 1U) - (T0 >> 1U);
- R1 = (R1 >> 1U) - (T1 >> 1U);
-
- /* Read yb (real), xb(imag) input */
- T0 = pSrc16[i1 * 2U];
- T1 = pSrc16[(i1 * 2U) + 1U];
-
- /* writing the butterfly processed i0 + fftLen/4 sample */
- /* xc' = (xa-xb+xc-xd) */
- /* yc' = (ya-yb+yc-yd) */
- pSrc16[i1 * 2U] = R0;
- pSrc16[(i1 * 2U) + 1U] = R1;
-
- /* Read yd (real), xd(imag) input */
- U0 = pSrc16[i3 * 2U];
- U1 = pSrc16[(i3 * 2U) + 1U];
- /* T0 = (yb - yd), T1 = (xb - xd) */
- T0 = __SSAT(T0 - U0, 16U);
- T1 = __SSAT(T1 - U1, 16U);
-
- /* writing the butterfly processed i0 + fftLen/2 sample */
- /* xb' = (xa-yb-xc+yd) */
- /* yb' = (ya+xb-yc-xd) */
- pSrc16[i2 * 2U] = (S0 >> 1U) - (T1 >> 1U);
- pSrc16[(i2 * 2U) + 1U] = (S1 >> 1U) + (T0 >> 1U);
-
-
- /* writing the butterfly processed i0 + 3fftLen/4 sample */
- /* xd' = (xa+yb-xc-yd) */
- /* yd' = (ya-xb-yc+xd) */
- pSrc16[i3 * 2U] = (S0 >> 1U) + (T1 >> 1U);
- pSrc16[(i3 * 2U) + 1U] = (S1 >> 1U) - (T0 >> 1U);
- }
- /* end of last stage process */
-
- /* output is in 11.5(q5) format for the 1024 point */
- /* output is in 9.7(q7) format for the 256 point */
- /* output is in 7.9(q9) format for the 64 point */
- /* output is in 5.11(q11) format for the 16 point */
-
-#endif /* #if defined (ARM_MATH_DSP) */
-
-}
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