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 Following a signal down through hierarchy with iterated instances 

Last post Thu, Oct 22 2009 10:03 AM by Ivars. 2 replies.
Started by Ivars 19 Oct 2009 09:47 AM. Topic has 2 replies and 1373 views
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  • Mon, Oct 19 2009 9:47 AM

    • Ivars
    • Not Ranked
    • Joined on Fri, Aug 28 2009
    • Posts 7
    • Points 95
    Following a signal down through hierarchy with iterated instances Reply


    I'm trying to write a procedure that will follow a signal down the hierarchy  and return a list of instances which were traversed.  I've been able to do this successfully, with the code below, as long as the path does not contain iterated instances. With iterated instances I'm struggling with how to map the signal name a one level to the name used at the next lower level.

     My basic approach is as follows:

     1) use dbFindSigByName to find the signal object assocaited with the desired signal at a given level of hierarchy.

    2) from the signal object, use instTerms to determine which instance terminals the signal is connected to and at which index of that terminal the desired signal is located

    3) for each instTerm, open the associated instance and use dbGetMemName to determine what name the original signal name was mapped to. 

     4) Repeat the whole procedure for the current instance with the mapped signal name until the desired stop cell is reached or it has descended into cell from a base cell library ("xxXxx"). At this point the instance path is printed out.

     When descending into an iterated instance the mapping step with dbGetMemName fails since it doesn't account for the iterated intances. For example, consider cellview where 3 iterated instances I<0:2>  have a net "upper<0:5>" connected to terminal "lower<0:1>". If I'm following the signal "upper<3>" down, I need to determine that "upper<3>" maps to "lower<1>" of instance I<1>. Are there any built-in functions to assist with this mapping or do I need to roll my own?

     Any help would be greatly appreciated.




    ;; usage: traceSignal("signal<2>" "stopCellName") 

     procedure(traceSignal(sig_name  stop_cell @optional (cv geGetEditCellView()) (sList '() ) (iList '("") ) (cList '() ) )
      let( (net_l net net_d sig_d sig sig_l instTerm_l instTerm bit)
          if(sig_d = dbFindSigByName(cv sig_name) ;; get the signal object for the signal name
           sList = cons(sig_name sList) ;; add signal name to hierarchical list
           foreach(instTerm_l sig_d~>memInstTerms
             instTerm = car(instTerm_l) ;; instance terminal to which signal connects
             bit = cadr(instTerm_l) ;; bit index of signal on instance terminal
             followDown(instTerm bit stop_cell sList iList cList)
           printf("Signal %s not found\n" sig_name)
         ); if(sig_d

    procedure(followDown(instTerm bit stop_cell sList iList cList)
      let((cv term_name inst_name inst_base_name inst_num cell_name lib_name sig_name)
          term_name = instTerm~>name
          inst_name = instTerm~>inst~>name
          cell_name = instTerm~>inst~>cellName
          lib_name  = instTerm~>inst~>libName
          iList = cons( inst_name iList) ;; add instance name to hierarchical list
          cList = cons( cell_name cList) ;; add cell name to hierarchical list
         if(lib_name == "xxXxx" || cell_name == stop_cell
           then ;; don't descend any further
               printf("%s\n" buildString( reverse(sList) " -> " ))
               printf("%s\n" buildString( reverse(cList) " : " ))
               printf("%s\n" buildString( reverse(iList) "/" ))
               when(cv = dbOpenCellViewByType(lib_name cell_name "schematic" ) ;; descend hierarchy
                    sig_name = dbGetMemName(term_name bit) ;; determine signal name at lower level
                    traceSignal(sig_name stop_cell cv sList iList cList) ;; look for signal
        ); if(lib_name

    • Post Points: 20
  • Wed, Oct 21 2009 1:54 PM

    • dmay
    • Top 25 Contributor
    • Joined on Thu, Jul 17 2008
    • Allen, TX
    • Posts 393
    • Points 7,415
    Re: Following a signal down through hierarchy with iterated instances Reply

    You'll hve to "roll your own", but this is all you really need:

    ; makes a list of lists of all instances and terminals of an iterated terminal.
    procedure( getInstAndTerm( memTerm)
      let( (
             ( term  car( memTerm))
             ( index cadr( memTerm))
             ( inst  car( memTerm)->inst)

        instNameMembers = dbProduceMemName( inst->name)
        termNameMembers = dbProduceMemName( term->name)
        foreach( instMember instNameMembers
          foreach( termMember termNameMembers
            instTermPairs = tconc( instTermPairs list( instMember termMember))

        nth( index car( instTermPairs))

    In your example:

    sig = dbFindSigByName(geGetEditCellView() "upper<3>")
    mit = car(sig~>memInstTerms)
      (db:0x2194a912 3)
    Notice the bit number 3.
    it = getInstAndTerm(mit)
    ("I<1>" "lower<1>")

    So essentially, the inst term pairs are:
    0: I<0> lower<0>
    1: I<0> lower<1>
    2: I<1> lower<0>
    3: I<1> lower<1>
    4: I<2> lower<0>
    5: I<2> lower<1>


    • Post Points: 20
  • Thu, Oct 22 2009 10:03 AM

    • Ivars
    • Not Ranked
    • Joined on Fri, Aug 28 2009
    • Posts 7
    • Points 95
    Re: Following a signal down through hierarchy with iterated instances Reply
    Derek, Thanks for the response. Your example worked. I'll incorporate it into my tracing function. Ivars
    • Post Points: 5
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Started by Ivars at 19 Oct 2009 09:47 AM. Topic has 2 replies.