I don't get what you mean between 8255-like and two serial port.

As I know, extra pins at MCS51 family (not include data and address bus):

P1 have 8 bits and P3 have 6 bits. So you have 14 bit that can be used as input or output(bidirectional), notice that T0, T1, IT0, IT1, Rx, Tx, are not used as it's functional pin (as a port only).

By setting all pin out to logic '1', you can use it as input and also as output. If you want to make 8052 as 8255-like, simply set every pins to logic '1'.

Take P1 as 8 bit bidirectional data.
Take T0, T1, IT0, IT1, as control bit.

Hope this satisfied you.