文件列表:

54ffts\BENCHM~1.DOC (45056, 1996-07-17)
54ffts\BIT_REV.ASM (3009, 1996-09-19)
54ffts\FFT.ASM (10540, 1996-09-19)
54ffts\FFT_SIZE.INC (1735, 1996-09-20)
54ffts\GO.BAT (38, 1996-09-19)
54ffts\INDATA1 (322, 1996-06-25)
54ffts\RFFT.ASM (15407, 1996-09-19)
54ffts\RFFT.CMD (778, 1996-07-03)
54ffts\RFFT.LST (90562, 1996-09-23)
54ffts\RFFT.MAP (2662, 1996-09-23)
54ffts\RFFT.OBJ (4086, 1996-09-23)
54ffts\RFFT.OUT (3730, 1996-09-23)
54ffts\TWIDDLE1 (18686, 1996-09-20)
54ffts\TWIDDLE2 (18697, 1996-09-20)
54ffts\VECTORS.LST (2085, 1996-09-23)
54ffts\VECTORS.OBJ (480, 1996-09-23)
54ffts\INITRFFT.ASM (2322, 1996-09-19)
54ffts\INITRFFT.LST (68143, 1996-09-23)
54ffts\INITRFFT.OBJ (3159, 1996-09-23)
54ffts\POWER.ASM (2350, 1996-09-19)
54ffts\BIT_REV.LST (4706, 1996-09-23)
54ffts\BIT_REV.OBJ (522, 1996-09-23)
54ffts\FFT.LST (16375, 1996-09-23)
54ffts\FFT.OBJ (1373, 1996-09-23)
54ffts\IFFT.ASM (11220, 1996-09-19)
54ffts\IFFT.CMD (778, 1996-07-03)
54ffts\IFFT.LST (83824, 1996-09-23)
54ffts\IFFT.MAP (2839, 1996-09-23)
54ffts\IFFT.OBJ (3852, 1996-09-23)
54ffts\IFFT.OUT (3640, 1996-09-23)
54ffts\POWER.LST (3634, 1996-09-23)
54ffts\POWER.OBJ (513, 1996-09-23)
54ffts\RFFT.BAT (178, 1996-09-23)
54ffts\RIFFT.ASM (15464, 1996-09-20)
54ffts\RIFFT.CMD (781, 1996-07-03)
54ffts\RIFFT.LST (91264, 1996-09-23)
54ffts\RIFFT.MAP (2848, 1996-09-23)
54ffts\RIFFT.OBJ (4086, 1996-09-23)
54ffts\RIFFT.OUT (3730, 1996-09-23)
... ...

;******************************************************************************** ; FILE NAME: readme.txt ; AUTHORS: Simon Lau and Nathan Baltz ; DESCRIPTION: This is a readme file for rFFT.asm. This document contains ; three sections: the first section describes in detail how the ; code runs; the second section gives an overview of the program ; and data usage; and the last section lists some benchmarks. ; DATE: Summer 1996 ;******************************************************************************** DESCRIPTION: ============ This code implements a 2N-point real FFT on the TMS320C54x processor. It uses a radix 2, in-place DIT algorithm. Real input sequences ranging from 16 to 1024 points can be used by simply modifying N and LOGN appropriately. Note that the input data must be in Q0.15 format. This code consists of four phases: In Phase One, the inputs are rearranged in a bit-reversed order. That way the final outputs will be in the correct, natural order. Specifically, the original 2N-point real sequence is temporarly stored into a contiguous section of memory labeled INPUT and is interpreted as an N-point complex input d[n] (where the even-indexed real inputs form the real part of d[n], and the odd-indexed real inputs form the imaginary part). We call this process "packing." Next we simply bit-reverse the order of this complex sequence and store it into another section of memory labeled DATA. In Phase Two, an N-point complex FFT is performed. Computation is done in place. The twiddle factors (sine and cosine) used are in Q0.15 format and are stored in two separate tables, TWIDDLE1 and TWIDDLE2. There are 512 values in each table representing angles ranging from 0 to (almost) 180 degrees. By indexing through the twiddle tables in the proper fashion, the same twiddle tables are used for real FFTs of different sizes. Phase Three separates the FFT output in order to compute four independent real sequences RP,RM,IP,IM, which are the even real part, odd real part, even imaginary part, and the odd imaginary part, respectively. Since the DFT and hence the FFT is a linear transform, this separation can be done correctly. The fourth and final phase performs one more set of butterflies in order to create the complex output which corresponds to the 2N-point complex FFT of the original 2N-point real input sequence. MEMORY USAGE: ============= The code takes 196 words of program space and (2*512+2N+3+16) = 2N+1043 words of data space. EXECUTION TIME: =============== # of real points = 2N : 16 32 *** 128 256 512 1024 Cycles : 377 769 1603 3393 7239 15485 33107

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