hi,
first of all, look at the subject of the thread you started. AT98C52 does not present. Do you mean AT89C52?

2) AT89C52 is not the same as 87C51FA.
- it has not PCA and its registers;
- it has not interrupts registers IPL0/IPH0/IPL1/IPH1; it has only IP

Regards,
Oleg