interrupting interrupt and eeprom access questions

I'm new to keil and my boss forced me to use atmel 89S8252 so plz bare with me i have a few questions :

1. when a higher level priority interrupt interrupts lower level interrupt, do i lose the old interrupt or does it come back to it after higher level priority interrupt returns ?

2.Can I declare eeprom variable in keil c or do i have to do it in low level (i.e access the registers)?