diff options
Diffstat (limited to 'platform/CMSIS/DSP_Lib/Source/TransformFunctions/arm_cfft_radix8_f32.c')
| -rw-r--r-- | platform/CMSIS/DSP_Lib/Source/TransformFunctions/arm_cfft_radix8_f32.c | 384 |
1 files changed, 384 insertions, 0 deletions
diff --git a/platform/CMSIS/DSP_Lib/Source/TransformFunctions/arm_cfft_radix8_f32.c b/platform/CMSIS/DSP_Lib/Source/TransformFunctions/arm_cfft_radix8_f32.c new file mode 100644 index 0000000..c6212c3 --- /dev/null +++ b/platform/CMSIS/DSP_Lib/Source/TransformFunctions/arm_cfft_radix8_f32.c @@ -0,0 +1,384 @@ +/* ---------------------------------------------------------------------- +* Copyright (C) 2010-2014 ARM Limited. All rights reserved. +* +* $Date: 31. July 2014 +* $Revision: V1.4.4 +* +* Project: CMSIS DSP Library +* Title: arm_cfft_radix8_f32.c +* +* Description: Radix-8 Decimation in Frequency CFFT & CIFFT Floating point processing function +* +* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0 +* +* Redistribution and use in source and binary forms, with or without +* modification, are permitted provided that the following conditions +* are met: +* - Redistributions of source code must retain the above copyright +* notice, this list of conditions and the following disclaimer. +* - Redistributions in binary form must reproduce the above copyright +* notice, this list of conditions and the following disclaimer in +* the documentation and/or other materials provided with the +* distribution. +* - Neither the name of ARM LIMITED nor the names of its contributors +* may be used to endorse or promote products derived from this +* software without specific prior written permission. +* +* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS +* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE +* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, +* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, +* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; +* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER +* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT +* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN +* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE +* POSSIBILITY OF SUCH DAMAGE. +* -------------------------------------------------------------------- */ + +#include "arm_math.h" + +/** +* @ingroup groupTransforms +*/ + +/** +* @defgroup Radix8_CFFT_CIFFT Radix-8 Complex FFT Functions +* +* \par +* Complex Fast Fourier Transform(CFFT) and Complex Inverse Fast Fourier Transform(CIFFT) is an efficient algorithm to compute Discrete Fourier Transform(DFT) and Inverse Discrete Fourier Transform(IDFT). +* Computational complexity of CFFT reduces drastically when compared to DFT. +* \par +* This set of functions implements CFFT/CIFFT +* for floating-point data types. The functions operates on in-place buffer which uses same buffer for input and output. +* Complex input is stored in input buffer in an interleaved fashion. +* +* \par +* The functions operate on blocks of input and output data and each call to the function processes +* <code>2*fftLen</code> samples through the transform. <code>pSrc</code> points to In-place arrays containing <code>2*fftLen</code> values. +* \par +* The <code>pSrc</code> points to the array of in-place buffer of size <code>2*fftLen</code> and inputs and outputs are stored in an interleaved fashion as shown below. +* <pre> {real[0], imag[0], real[1], imag[1],..} </pre> +* +* \par Lengths supported by the transform: +* \par +* Internally, the function utilize a Radix-8 decimation in frequency(DIF) algorithm +* and the size of the FFT supported are of the lengths [ 64, 512, 4096]. +* +* +* \par Algorithm: +* +* <b>Complex Fast Fourier Transform:</b> +* \par +* Input real and imaginary data: +* <pre> +* 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 +* </pre> +* where N is length of FFT +* \par +* Output real and imaginary data: +* <pre> +* X(4r) = xa'+ j * ya' +* X(4r+1) = xb'+ j * yb' +* X(4r+2) = xc'+ j * yc' +* X(4r+3) = xd'+ j * yd' +* </pre> +* \par +* Twiddle factors for Radix-8 FFT: +* <pre> +* Wn = co1 + j * (- si1) +* W2n = co2 + j * (- si2) +* W3n = co3 + j * (- si3) +* </pre> +* +* \par +* \image html CFFT.gif "Radix-8 Decimation-in Frequency Complex Fast Fourier Transform" +* +* \par +* Output from Radix-8 CFFT Results in Digit reversal order. Interchange middle two branches of every butterfly results in Bit reversed output. +* \par +* <b> Butterfly CFFT equations:</b> +* <pre> +* xa' = xa + xb + xc + xd +* ya' = ya + yb + yc + yd +* xc' = (xa+yb-xc-yd)* co1 + (ya-xb-yc+xd)* (si1) +* yc' = (ya-xb-yc+xd)* co1 - (xa+yb-xc-yd)* (si1) +* xb' = (xa-xb+xc-xd)* co2 + (ya-yb+yc-yd)* (si2) +* yb' = (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) +* </pre> +* +* \par +* where <code>fftLen</code> length of CFFT/CIFFT; <code>ifftFlag</code> Flag for selection of CFFT or CIFFT(Set ifftFlag to calculate CIFFT otherwise calculates CFFT); +* <code>bitReverseFlag</code> Flag for selection of output order(Set bitReverseFlag to output in normal order otherwise output in bit reversed order); +* <code>pTwiddle</code>points to array of twiddle coefficients; <code>pBitRevTable</code> points to the array of bit reversal table. +* <code>twidCoefModifier</code> modifier for twiddle factor table which supports all FFT lengths with same table; +* <code>pBitRevTable</code> modifier for bit reversal table which supports all FFT lengths with same table. +* <code>onebyfftLen</code> value of 1/fftLen to calculate CIFFT; +* +* \par Fixed-Point Behavior +* Care must be taken when using the fixed-point versions of the CFFT/CIFFT function. +* Refer to the function specific documentation below for usage guidelines. +*/ + + +/* +* @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); +} + +/** +* @} end of Radix8_CFFT_CIFFT group +*/ |