Coverage Methods

The covergroup provides a set of coverage methods as follows.

Methos (functions)	Description	Can be called on
void sample	Triggers covergroup sampling	covergroup
void start	Starts collecting coverage information	covergroup, coverpoint, cross
void stop	Stops collecting coverage information	covergroup, coverpoint, cross
void set_inst_name	Sets instance name to the given string	covergroup
real get_coverage	Returns cumulative or type coverage of all instances of coverage item.	covergroup, coverpoint, cross
real get_inst_coverage	Returns specific instance coverage on which it is called.	covergroup, coverpoint, cross

Coverage Methods Example

module func_coverage;
  bit [7:0] addr, data;
  covergroup c_group;
    cp1: coverpoint addr;
    cp2: coverpoint data;
    cp1_X_cp2: cross cp1, cp2;
  endgroup : c_group

  c_group cg = new();
  
  initial begin
    cg.start();
    cg.set_inst_name("my_cg");
    
    forever begin
      cg.sample();
      #5;
    end
  end
  
  initial begin
    $monitor("At time = %0t: addr = %0d, data = %0d", $time, addr, data);
    repeat(5) begin
      addr = $random;
      data = $random;
      #5;
    end
    cg.stop();
    $display("Coverage = %f", cg.get_coverage());
    $finish;
  end
  
endmodule

Output:

At time = 0: addr = 36, data = 129
At time = 5: addr = 9, data = 99
At time = 10: addr = 13, data = 141
At time = 15: addr = 101, data = 18
At time = 20: addr = 1, data = 13
Coverage = 5.777995

Functional Coverage