(I'm a little confused on the organization of where the interupt routine fits into eeprom)
80c51 fam hw desc pg 17 list the interrupt vector addresses.

assuming you program in assembler, if not state which C you use.


as an example: the timer 1 interrupt

org (or the equivalent for your assembler) 01bh ;T1 vector
ljmp ISRt1

anywhere in ROM
ISRt1:
...
... code
...
reti

have fun,

Erik