Generating unique values without randc

SystemVerilog
, ,
1

Is there a way to generate unique values for a 16-bit rand variable every time I call the randomize method? I know that the unique keyword creates unique values for a set of variables when the randomize method is called. But I am interested in generating values that are unique to the values created with the previous randomize calls.

2

In reply to Krishna9:


module top ;
  
  class rranc ;
    rand bit [15:0] val;
    int qval[$];
    
    constraint c_r{
      !(val inside {qval}) ;
    }
    
    function void post_randomize();
      if(qval.size >= 2**$bits(val)-1) 
        qval = {};
      qval.push_back(val);
    endfunction  
  endclass 
  
  initial begin 
    rranc r  = new ;
    repeat(32) begin 
      
      r.randomize();
      $display("%p",r);
      
    end 
    
  end
  
endmodule
3

In reply to Krishna9:

	
// This will be helpfull
class A;
typedef bit [15:0] my;
rand my value;
my value_queue[$];
constraint gen{unique{value,value_queue};}
function void post_randomize();
value_queue.push_back(value);
if(value_queue.size()==(2**16)) value_queue={};
endfunction
endclass
module top;
A a;	
initial begin
a=new;
for(int i=0; i<500; i++)begin
assert(a.randomize());
$write(" %d \t ",a.value);
end
end
endmodule