SV,class学习笔记五、参数化类(parameterized class)

1.改变类中传递的参数

//定义一个参数化类
class packet #(int size = 1);
    ......
endclass

//在创建句柄handle时改变参数
packet #(.size(16)) p2;

Example

class packet #(int size = 1); //定义参数化类
	bit [size-1 : 0] a;
endclass:packet

module tb;
 
	packet #(8) p1;       //改写参数
	packet #(.size(16))p2;//改写参数
	typedef packet #(.size(32)) mypacket; //声明一个与packet类别名的mypacket类同时改写参数
	mypacket p3;
	
	initial begin

		p1 = new;
		p2 = new;
		p3 = new;

		$display("[size] p1.a  =%0d",$bits(p1.a));
		$display("[size] p2.a  =%0d",$bits(p2.a));
		$display("[size] p3.a  =%0d",$bits(p3.a));	

	end
endmodule

Sim Log

 

 2.将数据类型参数化，便于改写数据类型。

//定义T为int型
class packet # （type T = int）;

    T t;
    .....

endclass

//将int改写为real 
packet #（real） p1；

example 

class packet #(type T = int);//将类里的int参数化
	
    T t;

	function T sum (T addr);//定义一个sun函数，返回值类型为T，传递参数类型为T
		return  t + addr;
	endfunction

endclass:packet

module tb;

	packet #(real) real_p1;    //将T改写为 real 
	packet #(bit[3:0]) bit_p2; //将T改写为 bit[3：0]
	packet p3;
	
	initial begin

		real_p1 = new;
		bit_p2 = new;
		p3 = new;

    //分别给类中三种不同类型的t赋值，打印
		real_p1.t = 1.1;
		$display("return  = %0.2f",real_p1.sum(10));

		bit_p2.t = 4'b0000;
		$display("return  = %0b",bit_p2.sum(4'b1010));

		p3.t = -1;
		$display("return  = %0d",p3.sum(10));	

	end
endmodule

sim log