The code is very simple, having bunch of ifs to put a certain value in
the variable BUS, the problem that on simulating, the BUS output equals :
while it's supposed to have certain values
corresponding to the if case.
module Bus (AR_OUT, IR_OUT,
DR_OUT, PC_OUT, AC_OUT, MEM_OUT, read, S, BUS);
input [11:0]PC_OUT ;