module test(); wire [7:0] value1; wire [9:0] value2; assign value1[3:0] = 4'd2; assign value2 = {1'b0, value1, 1'b1}; initial begin #2 $display("%b %b", value1, value2); if (value2 === 10'b0zzzz00101) $display("PASSED"); else $display("FAILED"); end endmodule