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[/] [dblclockfft/] - Rev 14

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  • Rev 14, 2015-03-07 02:19:30 GMT
  • Author: dgisselq
  • Log message:
    Found several bugs in the previous version. The biggest were in the qtrstage.
    Apparently, the qtrstage didn't work before, even though I thought it did.
    Further, the FFT testbench has been adjusted to place proper values into
    the fft_tb.dbl file it creates. (I've been testing it by reading this into
    Octave, and visually inspecting the results--quantitative testing of the
    fft_tb and ifft_tb are still lacking.) Now, however, if I cascade the
    forward and reverse together, I seem to get something at least close to the
    right answer. Close, of course, is relative. I think all that I still
    struggle with is rounding and truncation errors, hence I'm checking in
    my changes.

    The FFT generator was also modified to allow arbitrary length paths
    in the command line specified path prefix. This has not been tested.

    A bug was also found in the butterfly, whereby for certain multiply delays
    the butterfly would be unable to determine whether or not its results were
    valid. Adding an extra bit to the FIFO address in these cases fixed the
    problem. This change was encapsulated into the lgdelay() function, and
    an additional bflydelay function. In my frustration, I modified the
    fftstage function so that, when it is built, the parameters it is built
    with are the default parameters. This should only affect testing, by
    making any testing more realistic, but that may still remain to be seen.

    Another change was made to the core generator, so that now when a core
    is generated, the main file now contains a copy of the arguments that were
    used when the core generator was invoked. This is good for posterity, in
    case you ever need to ask yourself how I ended up here.

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