1reg[3:0] x; 2reg[3:0] COUNT = 0; 3 4always @(posedge clock.val) begin 5 if (x == 0) begin 6 x <= 1; 7 end else begin 8 x[3] <= x[2]; 9 x[2] <= x[1]; 10 x[1] <= x[0]; 11 x[0] <= x[3]; 12 end 13 14 $write("%d ", x); 15 COUNT <= COUNT + 1; 16 if (COUNT == 4) 17 $finish; 18end 19