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Diffstat (limited to 'Middlewares/Third_Party/ARM/ARM.CMSIS-DSP.1.17.1/Source/TransformFunctions/arm_rfft_fast_f64.c')
| -rwxr-xr-x | Middlewares/Third_Party/ARM/ARM.CMSIS-DSP.1.17.1/Source/TransformFunctions/arm_rfft_fast_f64.c | 236 |
1 files changed, 236 insertions, 0 deletions
diff --git a/Middlewares/Third_Party/ARM/ARM.CMSIS-DSP.1.17.1/Source/TransformFunctions/arm_rfft_fast_f64.c b/Middlewares/Third_Party/ARM/ARM.CMSIS-DSP.1.17.1/Source/TransformFunctions/arm_rfft_fast_f64.c new file mode 100755 index 0000000..80fede3 --- /dev/null +++ b/Middlewares/Third_Party/ARM/ARM.CMSIS-DSP.1.17.1/Source/TransformFunctions/arm_rfft_fast_f64.c @@ -0,0 +1,236 @@ +/* ---------------------------------------------------------------------- + * Project: CMSIS DSP Library + * Title: arm_rfft_fast_f64.c + * Description: RFFT & RIFFT Double precision Floating point process function + * + * $Date: 23 April 2021 + * $Revision: V1.9.0 + * + * Target Processor: Cortex-M and Cortex-A cores + * -------------------------------------------------------------------- */ + +/* + * Copyright (C) 2010-2021 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_compiler_specific.h" + + +#include "dsp/transform_functions.h" + +static void stage_rfft_f64( + const arm_rfft_fast_instance_f64 * S, + const float64_t * p, + float64_t * pOut) +{ + uint32_t k; /* Loop Counter */ + float64_t twR, twI; /* RFFT Twiddle coefficients */ + const float64_t * pCoeff = S->pTwiddleRFFT; /* Points to RFFT Twiddle factors */ + const float64_t *pA = p; /* increasing pointer */ + const float64_t *pB = p; /* decreasing pointer */ + float64_t xAR, xAI, xBR, xBI; /* temporary variables */ + float64_t t1a, t1b; /* temporary variables */ + float64_t p0, p1, p2, p3; /* temporary variables */ + + + k = (S->Sint).fftLen - 1; + + /* Pack first and last sample of the frequency domain together */ + + xBR = pB[0]; + xBI = pB[1]; + xAR = pA[0]; + xAI = pA[1]; + + twR = *pCoeff++ ; + twI = *pCoeff++ ; + + // U1 = XA(1) + XB(1); % It is real + t1a = xBR + xAR ; + + // U2 = XB(1) - XA(1); % It is imaginary + t1b = xBI + xAI ; + + // real(tw * (xB - xA)) = twR * (xBR - xAR) - twI * (xBI - xAI); + // imag(tw * (xB - xA)) = twI * (xBR - xAR) + twR * (xBI - xAI); + *pOut++ = 0.5 * ( t1a + t1b ); + *pOut++ = 0.5 * ( t1a - t1b ); + + // XA(1) = 1/2*( U1 - imag(U2) + i*( U1 +imag(U2) )); + pB = p + 2*k; + pA += 2; + + do + { + /* + function X = my_split_rfft(X, ifftFlag) + % X is a series of real numbers + L = length(X); + XC = X(1:2:end) +i*X(2:2:end); + XA = fft(XC); + XB = conj(XA([1 end:-1:2])); + TW = i*exp(-2*pi*i*[0:L/2-1]/L).'; + for l = 2:L/2 + XA(l) = 1/2 * (XA(l) + XB(l) + TW(l) * (XB(l) - XA(l))); + end + XA(1) = 1/2* (XA(1) + XB(1) + TW(1) * (XB(1) - XA(1))) + i*( 1/2*( XA(1) + XB(1) + i*( XA(1) - XB(1)))); + X = XA; + */ + + xBI = pB[1]; + xBR = pB[0]; + xAR = pA[0]; + xAI = pA[1]; + + twR = *pCoeff++; + twI = *pCoeff++; + + t1a = xBR - xAR ; + t1b = xBI + xAI ; + + // real(tw * (xB - xA)) = twR * (xBR - xAR) - twI * (xBI - xAI); + // imag(tw * (xB - xA)) = twI * (xBR - xAR) + twR * (xBI - xAI); + p0 = twR * t1a; + p1 = twI * t1a; + p2 = twR * t1b; + p3 = twI * t1b; + + *pOut++ = 0.5 * (xAR + xBR + p0 + p3 ); //xAR + *pOut++ = 0.5 * (xAI - xBI + p1 - p2 ); //xAI + + pA += 2; + pB -= 2; + k--; + } while (k > 0U); +} + +/* Prepares data for inverse cfft */ +static void merge_rfft_f64( + const arm_rfft_fast_instance_f64 * S, + const float64_t * p, + float64_t * pOut) +{ + uint32_t k; /* Loop Counter */ + float64_t twR, twI; /* RFFT Twiddle coefficients */ + const float64_t *pCoeff = S->pTwiddleRFFT; /* Points to RFFT Twiddle factors */ + const float64_t *pA = p; /* increasing pointer */ + const float64_t *pB = p; /* decreasing pointer */ + float64_t xAR, xAI, xBR, xBI; /* temporary variables */ + float64_t t1a, t1b, r, s, t, u; /* temporary variables */ + + k = (S->Sint).fftLen - 1; + + xAR = pA[0]; + xAI = pA[1]; + + pCoeff += 2 ; + + *pOut++ = 0.5 * ( xAR + xAI ); + *pOut++ = 0.5 * ( xAR - xAI ); + + pB = p + 2*k ; + pA += 2 ; + + while (k > 0U) + { + /* G is half of the frequency complex spectrum */ + //for k = 2:N + // Xk(k) = 1/2 * (G(k) + conj(G(N-k+2)) + Tw(k)*( G(k) - conj(G(N-k+2)))); + xBI = pB[1] ; + xBR = pB[0] ; + xAR = pA[0]; + xAI = pA[1]; + + twR = *pCoeff++; + twI = *pCoeff++; + + t1a = xAR - xBR ; + t1b = xAI + xBI ; + + r = twR * t1a; + s = twI * t1b; + t = twI * t1a; + u = twR * t1b; + + // real(tw * (xA - xB)) = twR * (xAR - xBR) - twI * (xAI - xBI); + // imag(tw * (xA - xB)) = twI * (xAR - xBR) + twR * (xAI - xBI); + *pOut++ = 0.5 * (xAR + xBR - r - s ); //xAR + *pOut++ = 0.5 * (xAI - xBI + t - u ); //xAI + + pA += 2; + pB -= 2; + k--; + } + +} + +/** + @ingroup RealFFT +*/ + +/** + @defgroup RealFFTF64 Real FFT F64 Functions +*/ + +/** + @addtogroup RealFFTF64 + @{ +*/ + +/** + @brief Processing function for the Double Precision floating-point real FFT. + @param[in] S points to an arm_rfft_fast_instance_f64 structure + @param[in] p points to input buffer (Source buffer is modified by this function.) + @param[in] pOut points to output buffer + @param[in] ifftFlag + - value = 0: RFFT + - value = 1: RIFFT + + @par Size of buffers according to the target architecture and datatype: + They are described on the page \ref transformbuffers "transform buffers". +*/ + +ARM_DSP_ATTRIBUTE void arm_rfft_fast_f64( + arm_rfft_fast_instance_f64 * S, + float64_t * p, + float64_t * pOut, + uint8_t ifftFlag) +{ + arm_cfft_instance_f64 * Sint = &(S->Sint); + Sint->fftLen = S->fftLenRFFT / 2; + + /* Calculation of Real FFT */ + if (ifftFlag) + { + /* Real FFT compression */ + merge_rfft_f64(S, p, pOut); + + /* Complex radix-4 IFFT process */ + arm_cfft_f64( Sint, pOut, ifftFlag, 1); + } + else + { + /* Calculation of RFFT of input */ + arm_cfft_f64( Sint, p, ifftFlag, 1); + + /* Real FFT extraction */ + stage_rfft_f64(S, p, pOut); + } +} + +/** +* @} end of RealFFTF64 group +*/ |