A semiconductor memory device comprises a memory cell array comprising a plurality of memory cells, and a filling command determiner that receives a command signal and an address signal and determines whether the command signal corresponds to a filling command. Upon determining that the command signal corresponds to a filling command, the filling command determiner connects a first source voltage to a bitline and connects a second source voltage to a complementary bitline corresponding to the bitline. The bitline is connected to a selected memory cell corresponding to the address signal.