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Defining Procedures from within a Pcell

ahamlett

With this code inside a pcell and myFunction used from within that pcell, no errors arise so is this a good practice?

I'm wondering if this might cause some errors down the line when a tool is reading the cadence database.

if(!procedurep(getd(stringToSymbol("myFunction"))) then
    procedure( myFunction(name)
        println(name stdout)
    )
)

 

  • I don't think that it is good practice to print (to stdout) from within a PCell.  I think that I've seen fprintf to stderr for debugging purposes.  Are you intending to keep this print statement in the code?  What happens when you Stream Out (pipo / strmout) ?  I've got a feeling that this may look okay in DFII, but programs like Stream Out would choke.

    BTW, why do you have "stringToSymbol("myFunction")" rather than 'myFunction ?

    Regards,

    Lawrence.

     

  •  Oh, I think I missed the point, sorry.

    You are asking if it is okay to define a procedure within a PCell?  If the procedure is going to be called outside the scope of the PCell then I would think it is a really bad idea - how do you know if the PCell that defines the procedure is going to run before the code that uses the procedure?  However, if the procedure is used only within the scope of the PCell code, then I would think it should be safe.

  • You could use:

      unless(isCallable('MyFunction)

        procedure(...)

      )

    The main issue with having all the functions defined this way within the pcell code is that the code vector could get too large, and you might hit the limit of code size. 

    The usual way to define auxilliary functions used within pcell code is to put them in (or load them from) the libInit.il of the library containing the pcell.

    Regards,

    Andrew.

  •  I am going to HAVE to agree with Lawrence and Andrew, defining procedures within a pcell is not a good idea. I would define them either before the pcDefinePcell or in a separate file and use libInit.il to load that procedure. Your implementation is very hard to debug.

    Inside a pcell, println causes an error. poport, the output port for println, is not available in the pcell interpreter. stdout and stderr are available so you should use fprintf:

    fprintf( stdout "%s => %L\n" pcCellView~>cellName outputValue )

     

    Ted

  • You might also want to define such a function outside your pcell, and of course you must follow the advices of previous posts telling you to use libInit.il to load it so it's defined when your pcell code is run.

     ;; Custom print function for debugging
    (defun print_debug (var)
      (if (boundp 'pcCellView)
          (fprintf stdout "%s => %L\n" pcCellView~>cellName var )
          (fprintf stdout "Top Level => %L\n" var )))

     

    Guillaume

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