// Creating a scaleable adder module adder_8(cout, sum, a, b, cin); parameter size = 8; /* declare a parameter. default required */ output cout; output [size-1:0] sum; // sum uses the size parameter input cin; input [size-1:0] a, b; // 'a' and 'b' use the size parameter assign {cout, sum} = a + b + cin; endmodule