Find the hardware inferred by the following code.

module test$($input $[3$:$0]a,$

input $[3$:$0]b,$

input $clk,$ rst $n,$

output reg $4\frac{\text{:}}{b}ar(0)$ sum$)$;

always $($posedge clk$)$

begin

if $(!$ rst$\_$n$)$

sum $5^{\text{'}}bo$;

else

sum ;

end

endmodule