RE: [sv-ec] random generator state for shallow copy

Yes this is what I know. The problem is with copying RNG state during
shallow copy. Should it be copied or no?
If this is copied then should same values be randomized?
 
DANiel

  _____  

From: Bresticker, Shalom [mailto:shalom.bresticker@intel.com] 
Sent: Wednesday, December 16, 2009 4:27 PM
To: Daniel Mlynek; sv-ec@server.eda.org
Cc: 'Mirek Forczek'
Subject: RE: [sv-ec] random generator state for shallow copy


Hi,
 
The LRM says,
"p2 = new p1;

The last statement has new executing a second time, thus creating a new
object p2, whose class properties are copied from p1. This is known as a
shallow copy. All of the variables are copied across integers, strings,
instance handles, etc. Objects, however, are not copied, only their handles;
as before, two names for the same object have been created. This is true
even if the class declaration includes the instantiation operator new"

Thus since i is a variable, not an object handle, c1.i and c2.i are
independent data objects. If i was an object handle, then c1.i and c2.i
would point to the same object.

Shalom


  _____  

From: owner-sv-ec@server.eda.org [mailto:owner-sv-ec@server.eda.org] On
Behalf Of Daniel Mlynek
Sent: Wednesday, December 16, 2009 3:00 PM
To: sv-ec@server.eda.org
Cc: 'Mirek Forczek'
Subject: [sv-ec] random generator state for shallow copy



How should below case work? Object ponited by c2 is created as a shalow copy
from object pointed by c1. Then both get randomized - should values
randomized for c1 and c2 be the same?

class C;
        rand int i,j;
        function new;
                $display("new");
        endfunction
        function void post_randomize;
                $display(i,j);
        endfunction
endclass

module top;
        C c1,c2;
        initial begin
                c1 = new;
                c1.j.rand_mode(0);
                c1.randomize();
                c2 = new c1; //<<<<<<<<<shalow copy
                c1.randomize(); 
                c2.randomize(); //should c1.i be equal c2.i ?????????????
                c1.randomize();
                c2.randomize(); //should c1.i be equal c2.i ??????????????
        end

endmodule


 
 
DANiel

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