Subversion Repositories dblclockfft

Last modification

• 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.