testsuite/synth/module01/tb_fulladder4.v

   1 module tb_fulladder4;
   2    reg cin;
   3    reg [3:0] a;
   4    reg [3:0] b;
   5    wire [3:0] res;
   6    wire       cout;
   7
   8    fulladder4 dut (.sum(res), .cout(cout), .a(a), .b(b), .cin(cin));
   9
  10    initial begin
  11       a <= 4'h7;
  12       b <= 4'h6;
  13       cin <= 0;
  14       # 1;
  15       $display("res=%b", res);
  16       if (res !== 4'hd || cout != 0)
  17         $fatal(1, "FAILURE");
  18
  19       cin <= 1;
  20       #1;
  21       $display("res=%b", res);
  22       if (res !== 4'he || cout != 0)
  23         $fatal(1, "FAILURE");
  24
  25       $display("PASS");
  26       $finish;
  27    end
  28 endmodule