下面是個四位的子模塊
//module cla.v
module cla(p,g,cin,c,gp,gg);
input [3:0] p;
input [3:0] g;
input cin;
output [3:0] c;
output gp;
output gg;
//assign
wire gp0;
wire gg0;
wire gp1;
wire gg1;
wire gp2;