Randomize enum data type

OVM
1

Hi,
Im looking to randomize a subset of a ‘typdef enum’ data type so that I choose one item of a subset of a number of items. How hsould I do it?
For eg:

`include "ovm.svh"
import ovm_pkg::*;
typedef enum {NO_ERR, ERR1, ERR2, ERR3, ERR4} err_kind;
class item extends ovm_object;
 
   rand bit [7:0] addr;
   rand bit [7:0] data;
   err_kind err_item;
     `ovm_object_utils_begin(item)
       `ovm_field_enum     (err_kind, err_item, OVM_ALL_ON)
       `ovm_field_int      (addr, OVM_ALL_ON)
       `ovm_field_int      (data, OVM_ALL_ON)
   `ovm_object_utils_end
 
  function new (string name = "");
    super.new(name);
  endfunction : new
endclass: item
//****************
module top;
   item packet = new();
 
   initial begin
      for(int i = 1; i<=(50); i++) begin
         void'(packet.randomize(err_item));// with {err_kind [NO_ERR,ERR3]});
         $display(" error = %s",packet.err_item.name());
      end
   $finish;
   end
 
endmodule

In this test case the err_item printed will be one of the all error types. But if I have to choose between only NO_ERR and ERR3, how shoud I do it?

Thank you,
Kaushik

2

Hi Sameer,

Please modify in-line constraint syntax as below:

void’(packet.randomize(err_item) with {err_item inside {ERR3, NO_ERR};});
OR
By declaring err_item variable “rand.” you can use below statement.
void’(packet.randomize() with {err_item inside {ERR3, NO_ERR};});

Regards,

3

Thanks Vaibhav!