| /* ---------------------------------------------------------------------- |
| * Project: CMSIS DSP Library |
| * Title: arm_cfft_radix4_f32.c |
| * Description: Radix-4 Decimation in Frequency CFFT & CIFFT Floating point processing function |
| * |
| * $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" |
| |
| extern void arm_bitreversal_f32( |
| float32_t * pSrc, |
| uint16_t fftSize, |
| uint16_t bitRevFactor, |
| uint16_t * pBitRevTab); |
| |
| void arm_radix4_butterfly_f32( |
| float32_t * pSrc, |
| uint16_t fftLen, |
| float32_t * pCoef, |
| uint16_t twidCoefModifier); |
| |
| void arm_radix4_butterfly_inverse_f32( |
| float32_t * pSrc, |
| uint16_t fftLen, |
| float32_t * pCoef, |
| uint16_t twidCoefModifier, |
| float32_t onebyfftLen); |
| |
| |
| /** |
| * @ingroup groupTransforms |
| */ |
| |
| /** |
| * @addtogroup ComplexFFT |
| * @{ |
| */ |
| |
| /** |
| * @details |
| * @brief Processing function for the floating-point Radix-4 CFFT/CIFFT. |
| * @deprecated Do not use this function. It has been superseded by \ref arm_cfft_f32 and will be removed |
| * in the future. |
| * @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 ComplexFFT 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; |
| |
| #if defined (ARM_MATH_DSP) |
| |
| /* 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; |
| float32_t p0,p1,p2,p3,p4,p5; |
| float32_t a0,a1,a2,a3,a4,a5,a6,a7; |
| |
| /* 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]; |
| |
| 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 */ |
| 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; |
| p0 = Yb12C_out * si1; |
| /* yb' = (ya-xb-yc+xd)co1 + (xa+yb-xc-yd)(si1) */ |
| //Yb12_out += Xb12C_out * si1; |
| p1 = Xb12C_out * si1; |
| /* xc' = (xa-xb+xc-xd)co2 - (ya-yb+yc-yd)(si2) */ |
| //Xc12_out -= Yc12C_out * si2; |
| p2 = Yc12C_out * si2; |
| /* yc' = (ya-yb+yc-yd)co2 + (xa-xb+xc-xd)(si2) */ |
| //Yc12_out += Xc12C_out * si2; |
| p3 = Xc12C_out * si2; |
| /* xd' = (xa-yb-xc+yd)co3 - (ya+xb-yc-xd)(si3) */ |
| //Xd12_out -= Yd12C_out * si3; |
| p4 = Yd12C_out * si3; |
| /* yd' = (ya+xb-yc-xd)co3 + (xa-yb-xc+yd)(si3) */ |
| //Yd12_out += Xd12C_out * si3; |
| p5 = Xd12C_out * si3; |
| |
| Xb12_out += p0; |
| Yb12_out -= p1; |
| Xc12_out += p2; |
| Yc12_out -= p3; |
| Xd12_out += p4; |
| Yd12_out -= p5; |
| |
| /* 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 += twidCoefModifier; |
| |
| /* Updating input index */ |
| i0++; |
| |
| } |
| while (--j); |
| |
| twidCoefModifier <<= 2U; |
| |
| /* Calculation of second stage to excluding last stage */ |
| for (k = fftLen >> 2U; k > 4U; k >>= 2U) |
| { |
| /* Initializations for the first stage */ |
| n1 = n2; |
| n2 >>= 2U; |
| ia1 = 0U; |
| |
| /* Calculation of first stage */ |
| j = 0; |
| do |
| { |
| /* 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 += twidCoefModifier; |
| |
| i0 = j; |
| 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]; |
| |
| 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; |
| p0 = Yb12C_out * si1; |
| /* yb' = (ya-xb-yc+xd)co1 + (xa+yb-xc-yd)(si1) */ |
| //Yb12_out += Xb12C_out * si1; |
| p1 = Xb12C_out * si1; |
| /* xc' = (xa-xb+xc-xd)co2 - (ya-yb+yc-yd)(si2) */ |
| //Xc12_out -= Yc12C_out * si2; |
| p2 = Yc12C_out * si2; |
| /* yc' = (ya-yb+yc-yd)co2 + (xa-xb+xc-xd)(si2) */ |
| //Yc12_out += Xc12C_out * si2; |
| p3 = Xc12C_out * si2; |
| /* xd' = (xa-yb-xc+yd)co3 - (ya+xb-yc-xd)(si3) */ |
| //Xd12_out -= Yd12C_out * si3; |
| p4 = Yd12C_out * si3; |
| /* yd' = (ya+xb-yc-xd)co3 + (xa-yb-xc+yd)(si3) */ |
| //Yd12_out += Xd12C_out * si3; |
| p5 = Xd12C_out * si3; |
| |
| Xb12_out += p0; |
| Yb12_out -= p1; |
| Xc12_out += p2; |
| Yc12_out -= p3; |
| Xd12_out += p4; |
| Yd12_out -= p5; |
| |
| /* 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; |
| |
| i0 += n1; |
| } while (i0 < fftLen); |
| j++; |
| } while (j <= (n2 - 1U)); |
| twidCoefModifier <<= 2U; |
| } |
| |
| j = fftLen >> 2; |
| ptr1 = &pSrc[0]; |
| |
| /* Calculations of last stage */ |
| do |
| { |
| xaIn = ptr1[0]; |
| yaIn = ptr1[1]; |
| xbIn = ptr1[2]; |
| ybIn = ptr1[3]; |
| xcIn = ptr1[4]; |
| ycIn = ptr1[5]; |
| xdIn = ptr1[6]; |
| ydIn = ptr1[7]; |
| |
| /* xa + xc */ |
| Xaplusc = xaIn + xcIn; |
| |
| /* xa - xc */ |
| Xaminusc = xaIn - xcIn; |
| |
| /* ya + yc */ |
| Yaplusc = yaIn + ycIn; |
| |
| /* ya - yc */ |
| Yaminusc = yaIn - ycIn; |
| |
| /* xb + xd */ |
| Xbplusd = xbIn + xdIn; |
| |
| /* yb + yd */ |
| Ybplusd = ybIn + ydIn; |
| |
| /* (xb-xd) */ |
| Xbminusd = xbIn - xdIn; |
| |
| /* (yb-yd) */ |
| Ybminusd = ybIn - ydIn; |
| |
| /* xa' = xa + xb + xc + xd */ |
| a0 = (Xaplusc + Xbplusd); |
| /* ya' = ya + yb + yc + yd */ |
| a1 = (Yaplusc + Ybplusd); |
| /* xc' = (xa-xb+xc-xd) */ |
| a2 = (Xaplusc - Xbplusd); |
| /* yc' = (ya-yb+yc-yd) */ |
| a3 = (Yaplusc - Ybplusd); |
| /* xb' = (xa+yb-xc-yd) */ |
| a4 = (Xaminusc + Ybminusd); |
| /* yb' = (ya-xb-yc+xd) */ |
| a5 = (Yaminusc - Xbminusd); |
| /* xd' = (xa-yb-xc+yd)) */ |
| a6 = (Xaminusc - Ybminusd); |
| /* yd' = (ya+xb-yc-xd) */ |
| a7 = (Xbminusd + Yaminusc); |
| |
| ptr1[0] = a0; |
| ptr1[1] = a1; |
| ptr1[2] = a2; |
| ptr1[3] = a3; |
| ptr1[4] = a4; |
| ptr1[5] = a5; |
| ptr1[6] = a6; |
| ptr1[7] = a7; |
| |
| /* increment pointer by 8 */ |
| 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 */ |
| j = 0; |
| do |
| { |
| /* 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; |
| |
| i0 = j; |
| 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; |
| |
| /* 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); |
| |
| i0 += n1; |
| } while ( i0 < fftLen); |
| j++; |
| } while (j <= (n2 - 1U)); |
| twidCoefModifier <<= 2U; |
| } |
| |
| #endif /* #if defined (ARM_MATH_DSP) */ |
| |
| } |
| |
| /* |
| * @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; |
| |
| #if defined (ARM_MATH_DSP) |
| |
| 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; |
| float32_t p0,p1,p2,p3,p4,p5,p6,p7; |
| float32_t a0,a1,a2,a3,a4,a5,a6,a7; |
| |
| |
| /* 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; |
| p0 = Yb12C_out * si1; |
| /* yb' = (ya-xb-yc+xd)co1 + (xa+yb-xc-yd)(si1) */ |
| //Yb12_out += Xb12C_out * si1; |
| p1 = Xb12C_out * si1; |
| /* xc' = (xa-xb+xc-xd)co2 - (ya-yb+yc-yd)(si2) */ |
| //Xc12_out -= Yc12C_out * si2; |
| p2 = Yc12C_out * si2; |
| /* yc' = (ya-yb+yc-yd)co2 + (xa-xb+xc-xd)(si2) */ |
| //Yc12_out += Xc12C_out * si2; |
| p3 = Xc12C_out * si2; |
| /* xd' = (xa-yb-xc+yd)co3 - (ya+xb-yc-xd)(si3) */ |
| //Xd12_out -= Yd12C_out * si3; |
| p4 = Yd12C_out * si3; |
| /* yd' = (ya+xb-yc-xd)co3 + (xa-yb-xc+yd)(si3) */ |
| //Yd12_out += Xd12C_out * si3; |
| p5 = Xd12C_out * si3; |
| |
| Xb12_out -= p0; |
| Yb12_out += p1; |
| Xc12_out -= p2; |
| Yc12_out += p3; |
| Xd12_out -= p4; |
| Yd12_out += p5; |
| |
| /* 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 >> 2U; k > 4U; k >>= 2U) |
| { |
| /* Initializations for the first stage */ |
| n1 = n2; |
| n2 >>= 2U; |
| ia1 = 0U; |
| |
| /* Calculation of first stage */ |
| j = 0; |
| do |
| { |
| /* 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; |
| |
| i0 = j; |
| 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]; |
| |
| 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; |
| p0 = Yb12C_out * si1; |
| /* yb' = (ya-xb-yc+xd)co1 + (xa+yb-xc-yd)(si1) */ |
| //Yb12_out += Xb12C_out * si1; |
| p1 = Xb12C_out * si1; |
| /* xc' = (xa-xb+xc-xd)co2 - (ya-yb+yc-yd)(si2) */ |
| //Xc12_out -= Yc12C_out * si2; |
| p2 = Yc12C_out * si2; |
| /* yc' = (ya-yb+yc-yd)co2 + (xa-xb+xc-xd)(si2) */ |
| //Yc12_out += Xc12C_out * si2; |
| p3 = Xc12C_out * si2; |
| /* xd' = (xa-yb-xc+yd)co3 - (ya+xb-yc-xd)(si3) */ |
| //Xd12_out -= Yd12C_out * si3; |
| p4 = Yd12C_out * si3; |
| /* yd' = (ya+xb-yc-xd)co3 + (xa-yb-xc+yd)(si3) */ |
| //Yd12_out += Xd12C_out * si3; |
| p5 = Xd12C_out * si3; |
| |
| Xb12_out -= p0; |
| Yb12_out += p1; |
| Xc12_out -= p2; |
| Yc12_out += p3; |
| Xd12_out -= p4; |
| Yd12_out += p5; |
| |
| /* 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; |
| |
| i0 += n1; |
| } while (i0 < fftLen); |
| j++; |
| } while (j <= (n2 - 1U)); |
| twidCoefModifier <<= 2U; |
| } |
| /* Initializations of last stage */ |
| |
| j = fftLen >> 2; |
| ptr1 = &pSrc[0]; |
| |
| /* Calculations of last stage */ |
| do |
| { |
| xaIn = ptr1[0]; |
| yaIn = ptr1[1]; |
| xbIn = ptr1[2]; |
| ybIn = ptr1[3]; |
| xcIn = ptr1[4]; |
| ycIn = ptr1[5]; |
| xdIn = ptr1[6]; |
| ydIn = ptr1[7]; |
| |
| /* Butterfly implementation */ |
| /* xa + xc */ |
| Xaplusc = xaIn + xcIn; |
| |
| /* xa - xc */ |
| Xaminusc = xaIn - xcIn; |
| |
| /* ya + yc */ |
| Yaplusc = yaIn + ycIn; |
| |
| /* ya - yc */ |
| Yaminusc = yaIn - ycIn; |
| |
| /* xb + xd */ |
| Xbplusd = xbIn + xdIn; |
| |
| /* yb + yd */ |
| Ybplusd = ybIn + ydIn; |
| |
| /* (xb-xd) */ |
| Xbminusd = xbIn - xdIn; |
| |
| /* (yb-yd) */ |
| Ybminusd = ybIn - ydIn; |
| |
| /* xa' = (xa+xb+xc+xd) * onebyfftLen */ |
| a0 = (Xaplusc + Xbplusd); |
| /* ya' = (ya+yb+yc+yd) * onebyfftLen */ |
| a1 = (Yaplusc + Ybplusd); |
| /* xc' = (xa-xb+xc-xd) * onebyfftLen */ |
| a2 = (Xaplusc - Xbplusd); |
| /* yc' = (ya-yb+yc-yd) * onebyfftLen */ |
| a3 = (Yaplusc - Ybplusd); |
| /* xb' = (xa-yb-xc+yd) * onebyfftLen */ |
| a4 = (Xaminusc - Ybminusd); |
| /* yb' = (ya+xb-yc-xd) * onebyfftLen */ |
| a5 = (Yaminusc + Xbminusd); |
| /* xd' = (xa-yb-xc+yd) * onebyfftLen */ |
| a6 = (Xaminusc + Ybminusd); |
| /* yd' = (ya-xb-yc+xd) * onebyfftLen */ |
| a7 = (Yaminusc - Xbminusd); |
| |
| p0 = a0 * onebyfftLen; |
| p1 = a1 * onebyfftLen; |
| p2 = a2 * onebyfftLen; |
| p3 = a3 * onebyfftLen; |
| p4 = a4 * onebyfftLen; |
| p5 = a5 * onebyfftLen; |
| p6 = a6 * onebyfftLen; |
| p7 = a7 * onebyfftLen; |
| |
| /* xa' = (xa+xb+xc+xd) * onebyfftLen */ |
| ptr1[0] = p0; |
| /* ya' = (ya+yb+yc+yd) * onebyfftLen */ |
| ptr1[1] = p1; |
| /* xc' = (xa-xb+xc-xd) * onebyfftLen */ |
| ptr1[2] = p2; |
| /* yc' = (ya-yb+yc-yd) * onebyfftLen */ |
| ptr1[3] = p3; |
| /* xb' = (xa-yb-xc+yd) * onebyfftLen */ |
| ptr1[4] = p4; |
| /* yb' = (ya+xb-yc-xd) * onebyfftLen */ |
| ptr1[5] = p5; |
| /* xd' = (xa-yb-xc+yd) * onebyfftLen */ |
| ptr1[6] = p6; |
| /* yd' = (ya-xb-yc+xd) * onebyfftLen */ |
| ptr1[7] = p7; |
| |
| /* 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 */ |
| j = 0; |
| do |
| { |
| /* 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; |
| |
| i0 = j; |
| 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; |
| |
| /* 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); |
| |
| i0 += n1; |
| } while ( i0 < fftLen); |
| j++; |
| } while (j <= (n2 - 1U)); |
| 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 /* #if defined (ARM_MATH_DSP) */ |
| } |
| |
| |
