Generate Unique Random Values SystemVerilog
In SystemVerilog below is one of the method,
- to generate unique values to set of variables or
- unique elements to an array
This can be achieved using Unique constraint.
Unique constraint can be used to generate unique values across the variables, generate unique elements in an array (Fixed Size Array, Dynamic Array, Associative array and Queue) .
In below example the variables (var_1, var_2 and var_3) are constrained using keyword unique, On randomization which leads to generation of unique values to the variables.
Same way to an array (array), random unique elements can be generated by constraining array with unique keyword.
class unique_elements;
rand bit [3:0] var_1,var_2,var_3;
rand bit [7:0] array[6];
constraint array_c {unique {array};}
function void display();
$display("var_1 = %p",var_1);
$display("var_2 = %p",var_2);
$display("var_3 = %p",var_3);
$display("array = %p",array);
endfunction
endclass
program unique_elements_randomization;
unique_elements pkt;
initial begin
pkt = new();
pkt.randomize();
pkt.display();
end
endprogram
Simulator Output
var_1 = 8
var_2 = 14
var_3 = 11
array = '{'h81, 'h7b, 'h4, 'h47, 'he1, 'h17}
