UVM Primer

virtual class animal;
   protected int age=-1;
   protected string name;

   function new(int a, string n);
      age = a;
      name = n;
   endfunction : new

   function int get_age();
        return age;
   endfunction : get_age

   function string get_name();
      return name;
   endfunction : get_name

   pure virtual function void make_sound();


endclass : animal


class lion extends animal;

   protected string        name;

   function new(int age, string n);
      super.new(age, n);
   endfunction : new

   function void make_sound();
      $display ("The lion, %s, says Roar", get_name());
   endfunction : make_sound


endclass : lion


class chicken extends animal;

   function new(int age, string n);
      super.new(age, n);
   endfunction : new

   function void make_sound();
      $display ("The Chicken, %s, says BECAWW", get_name());
   endfunction : make_sound



endclass : chicken
        
//animal_cage的代码跟lion_cage基本一样，除了前者带有一个参数。
//在第一行可以看见我们定义的type参数T，然后我们用这个参数来定义队列的类型，并用作cage_animal的参数类型

class animal_cage #(type T);
   protected static T cage[$]; //用参数来定义队列的类型
   static function void cage_animal(T l);  //将参数用作cage_animal的参数类型
      cage.push_back(l);
   endfunction : cage_animal

   static function void list_animals();
      $display("Animals in cage:"); 
      foreach (cage[i])
        $display(cage[i].get_name());
   endfunction : list_animals

endclass : animal_cage

   
module top;


   initial begin
      lion   lion_h;
      chicken  chicken_h;
      lion_h = new(15, "Mustafa");
      animal_cage #(lion)::cage_animal(lion_h);  //用lion类作为参数来访问cage_animal静态方法
      lion_h = new(15, "Simba");   //释放
      animal_cage #(lion)::cage_animal(lion_h);

      chicken_h = new(1, "Clucker");
      animal_cage #(chicken)::cage_animal(chicken_h); //用chicken类作为参数来访问cage_animal静态方法
      chicken_h = new(1, "Scratchy");
      animal_cage #(chicken)::cage_animal(chicken_h);

      $display("-- Lions --");
      animal_cage #(lion)::list_animals();
      $display("-- Chickens --");
      animal_cage #(chicken)::list_animals();
   end

endmodule : top

每当例化一个参数化类，你用不同的参数创建的类都是不同的

下面的例子中，我们不用静态方法来访问动物笼子了，我们要开始用例化的动物笼子对象来存放其他的动物

virtual class animal;
   protected int age=-1;
   protected string name;

   function new(int a, string n);
      age = a;
      name = n;
   endfunction : new

   function int get_age();
        return age;
   endfunction : get_age

   function string get_name();
      return name;
   endfunction : get_name

   pure virtual function void make_sound();


endclass : animal


class lion extends animal;

   protected string        name;

   function new(int age, string n);
      super.new(age, n);
   endfunction : new

   function void make_sound();
      $display ("The lion, %s, says Roar", get_name());
   endfunction : make_sound


endclass : lion


class chicken extends animal;

   function new(int age, string n);
      super.new(age, n);
   endfunction : new

   function void make_sound();
      $display ("The Chicken, %s, says BECAWW", get_name());
   endfunction : make_sound



endclass : chicken
        

class animal_cage #(type T);

   protected T cage[$];

   function void cage_animal(T l);  //注意此处，去掉了static
      cage.push_back(l);
   endfunction : cage_animal

   function void list_animals();    //注意此处，去掉static
      $display("Animals in cage:"); 
      foreach (cage[i])
        $display(cage[i].get_name());
   endfunction : list_animals

endclass : animal_cage

   

module top;
   
   lion   lion_h;
   chicken  chicken_h;

   animal_cage #(lion)  lion_cage; 
   animal_cage #(chicken) chicken_cage;
  
   

   initial begin
      lion_cage = new();   //例化一个新的狮子笼对象
      lion_h = new(15, "Mustafa");
      lion_cage.cage_animal(lion_h);
      lion_h = new(15, "Simba");
      lion_cage.cage_animal(lion_h);

      chicken_cage = new();  //例化新的chicken_cage
      chicken_h = new(1, "Little Red Hen");
      chicken_cage.cage_animal(chicken_h);

      chicken_h = new(1, "Lady Clucksalot");
      chicken_cage.cage_animal(chicken_h);
   

      $display("-- Lions --");
      lion_cage.list_animals();
      $display("-- Chickens --");
      chicken_cage.list_animals();
   end

endmodule : top