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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