[sv-bc] configurations and parameters

As I discussed during the conference on Monday - I would like to pursue 
the enhancement of setting parameters via configurations.  The 
discussion on Monday noted that there are a number of issues regarding 
configurations that need to be addressed, with setting parameters via 
configurations being just one of many.  I was tasked (volunteered) to 
gather up the issue/wish list regarding configurations and then start 
working through it.  Based on the verbal discussion we had on 
configurations and the need to have all items resolved by Nov 1 in order 
to be part of the next 1800 spec, I see a large task at hand.  I  feel 
we might have to take small steps - put some of the easier enhancements 
in now and add the rest in the next rev.  Of course I am just 
speculating at this point.

My enhancement request/proposal for configurations is to add the ability 
to set/modify parameters within a configuration.  I have pieced together 
some sample code that shows how I think this could work.

// Obviously, parameters set by configurations
//   must take precedent over instantiation parameter values.
// For this example, I assume that for models from different lib's,
//   the port list for each model are (must be?) identical.

module top ();
  //See configuration below for details of these instantiations.
  adder a1 (...);
  adder a2 (...);
  adder a3 #(.size(4)) (...);
  adder a4 (...);
  adder a5 #(.out(16)) (...);
  adder a6 #(.out(32)) (...);
endmodule // top

//file adder.v, default rtlLib
module adder #(parameter size = 12) (...);
  // rtl adder
  // description
  ...
endmodule // adder


//file adder2.v, in diffRTLLib
module adder #(parameter out = 10) (...);
  // different rtl adder
  // description
  ...
endmodule // adder


//file adder.vg, in gateLib
module adder (...);
  // gate-level adder
  // description
  ...
endmodule // adder


//This configuration is very verbose for discussion purposes.
config cfgl;
  design rtlLib.top;
  default liblist rtlLIb;
  instance top.a2 liblist gateLib;

  //default default lib, override instantiated parameter setting .size(4)
  instance top.a3 #(.size(16)); //adder from default liblist

  //different RTLLib, used parameter setting from module,
  //not changed by instantiation or configuration
  instance top.a4 liblist diffRTLLib; //adder from other than default 
liblist

  //different RTLLib, parameter is changed by instantiation but not 
configuration 
  instance top.a5 liblist diffRTLLib; //adder from other than default 
liblist

  //different rtl lib, overriding instantiated parameter setting of .out(32)
  instance top.a6 #(.out(8)) liblist diffRTLLib; //adder from other than 
default liblist

endconfig


--
==========================================================
Don Mills
mills@lcdm-eng.com
www.lcdm-eng.com
==========================================================


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