| /* ---------------------------------------------------------------------- |
| * Project: CMSIS DSP Library |
| * Title: arm_cfft_radix8_f32.c |
| * Description: Radix-8 Decimation in Frequency CFFT & CIFFT Floating point processing function |
| * |
| * $Date: 18. March 2019 |
| * $Revision: V1.6.0 |
| * |
| * Target Processor: Cortex-M cores |
| * -------------------------------------------------------------------- */ |
| /* |
| * Copyright (C) 2010-2019 ARM Limited or its affiliates. All rights reserved. |
| * |
| * SPDX-License-Identifier: Apache-2.0 |
| * |
| * Licensed under the Apache License, Version 2.0 (the License); you may |
| * not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an AS IS BASIS, WITHOUT |
| * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| #include "arm_math.h" |
| |
| |
| /* ---------------------------------------------------------------------- |
| * Internal 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_radix8_butterfly_f32( |
| float32_t * pSrc, |
| uint16_t fftLen, |
| const float32_t * pCoef, |
| uint16_t twidCoefModifier) |
| { |
| uint32_t ia1, ia2, ia3, ia4, ia5, ia6, ia7; |
| uint32_t i1, i2, i3, i4, i5, i6, i7, i8; |
| uint32_t id; |
| uint32_t n1, n2, j; |
| |
| float32_t r1, r2, r3, r4, r5, r6, r7, r8; |
| float32_t t1, t2; |
| float32_t s1, s2, s3, s4, s5, s6, s7, s8; |
| float32_t p1, p2, p3, p4; |
| float32_t co2, co3, co4, co5, co6, co7, co8; |
| float32_t si2, si3, si4, si5, si6, si7, si8; |
| const float32_t C81 = 0.70710678118f; |
| |
| n2 = fftLen; |
| |
| do |
| { |
| n1 = n2; |
| n2 = n2 >> 3; |
| i1 = 0; |
| |
| do |
| { |
| i2 = i1 + n2; |
| i3 = i2 + n2; |
| i4 = i3 + n2; |
| i5 = i4 + n2; |
| i6 = i5 + n2; |
| i7 = i6 + n2; |
| i8 = i7 + n2; |
| r1 = pSrc[2 * i1] + pSrc[2 * i5]; |
| r5 = pSrc[2 * i1] - pSrc[2 * i5]; |
| r2 = pSrc[2 * i2] + pSrc[2 * i6]; |
| r6 = pSrc[2 * i2] - pSrc[2 * i6]; |
| r3 = pSrc[2 * i3] + pSrc[2 * i7]; |
| r7 = pSrc[2 * i3] - pSrc[2 * i7]; |
| r4 = pSrc[2 * i4] + pSrc[2 * i8]; |
| r8 = pSrc[2 * i4] - pSrc[2 * i8]; |
| t1 = r1 - r3; |
| r1 = r1 + r3; |
| r3 = r2 - r4; |
| r2 = r2 + r4; |
| pSrc[2 * i1] = r1 + r2; |
| pSrc[2 * i5] = r1 - r2; |
| r1 = pSrc[2 * i1 + 1] + pSrc[2 * i5 + 1]; |
| s5 = pSrc[2 * i1 + 1] - pSrc[2 * i5 + 1]; |
| r2 = pSrc[2 * i2 + 1] + pSrc[2 * i6 + 1]; |
| s6 = pSrc[2 * i2 + 1] - pSrc[2 * i6 + 1]; |
| s3 = pSrc[2 * i3 + 1] + pSrc[2 * i7 + 1]; |
| s7 = pSrc[2 * i3 + 1] - pSrc[2 * i7 + 1]; |
| r4 = pSrc[2 * i4 + 1] + pSrc[2 * i8 + 1]; |
| s8 = pSrc[2 * i4 + 1] - pSrc[2 * i8 + 1]; |
| t2 = r1 - s3; |
| r1 = r1 + s3; |
| s3 = r2 - r4; |
| r2 = r2 + r4; |
| pSrc[2 * i1 + 1] = r1 + r2; |
| pSrc[2 * i5 + 1] = r1 - r2; |
| pSrc[2 * i3] = t1 + s3; |
| pSrc[2 * i7] = t1 - s3; |
| pSrc[2 * i3 + 1] = t2 - r3; |
| pSrc[2 * i7 + 1] = t2 + r3; |
| r1 = (r6 - r8) * C81; |
| r6 = (r6 + r8) * C81; |
| r2 = (s6 - s8) * C81; |
| s6 = (s6 + s8) * C81; |
| t1 = r5 - r1; |
| r5 = r5 + r1; |
| r8 = r7 - r6; |
| r7 = r7 + r6; |
| t2 = s5 - r2; |
| s5 = s5 + r2; |
| s8 = s7 - s6; |
| s7 = s7 + s6; |
| pSrc[2 * i2] = r5 + s7; |
| pSrc[2 * i8] = r5 - s7; |
| pSrc[2 * i6] = t1 + s8; |
| pSrc[2 * i4] = t1 - s8; |
| pSrc[2 * i2 + 1] = s5 - r7; |
| pSrc[2 * i8 + 1] = s5 + r7; |
| pSrc[2 * i6 + 1] = t2 - r8; |
| pSrc[2 * i4 + 1] = t2 + r8; |
| |
| i1 += n1; |
| } while (i1 < fftLen); |
| |
| if (n2 < 8) |
| break; |
| |
| ia1 = 0; |
| j = 1; |
| |
| do |
| { |
| /* index calculation for the coefficients */ |
| id = ia1 + twidCoefModifier; |
| ia1 = id; |
| ia2 = ia1 + id; |
| ia3 = ia2 + id; |
| ia4 = ia3 + id; |
| ia5 = ia4 + id; |
| ia6 = ia5 + id; |
| ia7 = ia6 + id; |
| |
| co2 = pCoef[2 * ia1]; |
| co3 = pCoef[2 * ia2]; |
| co4 = pCoef[2 * ia3]; |
| co5 = pCoef[2 * ia4]; |
| co6 = pCoef[2 * ia5]; |
| co7 = pCoef[2 * ia6]; |
| co8 = pCoef[2 * ia7]; |
| si2 = pCoef[2 * ia1 + 1]; |
| si3 = pCoef[2 * ia2 + 1]; |
| si4 = pCoef[2 * ia3 + 1]; |
| si5 = pCoef[2 * ia4 + 1]; |
| si6 = pCoef[2 * ia5 + 1]; |
| si7 = pCoef[2 * ia6 + 1]; |
| si8 = pCoef[2 * ia7 + 1]; |
| |
| i1 = j; |
| |
| do |
| { |
| /* index calculation for the input */ |
| i2 = i1 + n2; |
| i3 = i2 + n2; |
| i4 = i3 + n2; |
| i5 = i4 + n2; |
| i6 = i5 + n2; |
| i7 = i6 + n2; |
| i8 = i7 + n2; |
| r1 = pSrc[2 * i1] + pSrc[2 * i5]; |
| r5 = pSrc[2 * i1] - pSrc[2 * i5]; |
| r2 = pSrc[2 * i2] + pSrc[2 * i6]; |
| r6 = pSrc[2 * i2] - pSrc[2 * i6]; |
| r3 = pSrc[2 * i3] + pSrc[2 * i7]; |
| r7 = pSrc[2 * i3] - pSrc[2 * i7]; |
| r4 = pSrc[2 * i4] + pSrc[2 * i8]; |
| r8 = pSrc[2 * i4] - pSrc[2 * i8]; |
| t1 = r1 - r3; |
| r1 = r1 + r3; |
| r3 = r2 - r4; |
| r2 = r2 + r4; |
| pSrc[2 * i1] = r1 + r2; |
| r2 = r1 - r2; |
| s1 = pSrc[2 * i1 + 1] + pSrc[2 * i5 + 1]; |
| s5 = pSrc[2 * i1 + 1] - pSrc[2 * i5 + 1]; |
| s2 = pSrc[2 * i2 + 1] + pSrc[2 * i6 + 1]; |
| s6 = pSrc[2 * i2 + 1] - pSrc[2 * i6 + 1]; |
| s3 = pSrc[2 * i3 + 1] + pSrc[2 * i7 + 1]; |
| s7 = pSrc[2 * i3 + 1] - pSrc[2 * i7 + 1]; |
| s4 = pSrc[2 * i4 + 1] + pSrc[2 * i8 + 1]; |
| s8 = pSrc[2 * i4 + 1] - pSrc[2 * i8 + 1]; |
| t2 = s1 - s3; |
| s1 = s1 + s3; |
| s3 = s2 - s4; |
| s2 = s2 + s4; |
| r1 = t1 + s3; |
| t1 = t1 - s3; |
| pSrc[2 * i1 + 1] = s1 + s2; |
| s2 = s1 - s2; |
| s1 = t2 - r3; |
| t2 = t2 + r3; |
| p1 = co5 * r2; |
| p2 = si5 * s2; |
| p3 = co5 * s2; |
| p4 = si5 * r2; |
| pSrc[2 * i5] = p1 + p2; |
| pSrc[2 * i5 + 1] = p3 - p4; |
| p1 = co3 * r1; |
| p2 = si3 * s1; |
| p3 = co3 * s1; |
| p4 = si3 * r1; |
| pSrc[2 * i3] = p1 + p2; |
| pSrc[2 * i3 + 1] = p3 - p4; |
| p1 = co7 * t1; |
| p2 = si7 * t2; |
| p3 = co7 * t2; |
| p4 = si7 * t1; |
| pSrc[2 * i7] = p1 + p2; |
| pSrc[2 * i7 + 1] = p3 - p4; |
| r1 = (r6 - r8) * C81; |
| r6 = (r6 + r8) * C81; |
| s1 = (s6 - s8) * C81; |
| s6 = (s6 + s8) * C81; |
| t1 = r5 - r1; |
| r5 = r5 + r1; |
| r8 = r7 - r6; |
| r7 = r7 + r6; |
| t2 = s5 - s1; |
| s5 = s5 + s1; |
| s8 = s7 - s6; |
| s7 = s7 + s6; |
| r1 = r5 + s7; |
| r5 = r5 - s7; |
| r6 = t1 + s8; |
| t1 = t1 - s8; |
| s1 = s5 - r7; |
| s5 = s5 + r7; |
| s6 = t2 - r8; |
| t2 = t2 + r8; |
| p1 = co2 * r1; |
| p2 = si2 * s1; |
| p3 = co2 * s1; |
| p4 = si2 * r1; |
| pSrc[2 * i2] = p1 + p2; |
| pSrc[2 * i2 + 1] = p3 - p4; |
| p1 = co8 * r5; |
| p2 = si8 * s5; |
| p3 = co8 * s5; |
| p4 = si8 * r5; |
| pSrc[2 * i8] = p1 + p2; |
| pSrc[2 * i8 + 1] = p3 - p4; |
| p1 = co6 * r6; |
| p2 = si6 * s6; |
| p3 = co6 * s6; |
| p4 = si6 * r6; |
| pSrc[2 * i6] = p1 + p2; |
| pSrc[2 * i6 + 1] = p3 - p4; |
| p1 = co4 * t1; |
| p2 = si4 * t2; |
| p3 = co4 * t2; |
| p4 = si4 * t1; |
| pSrc[2 * i4] = p1 + p2; |
| pSrc[2 * i4 + 1] = p3 - p4; |
| |
| i1 += n1; |
| } while (i1 < fftLen); |
| |
| j++; |
| } while (j < n2); |
| |
| twidCoefModifier <<= 3; |
| } while (n2 > 7); |
| } |
