when an interrupt ocurrs, how many cycles does it take to the 8051 in order to prepare the conditions for the interrupt. (ie. LCALL uses 2 cycles)

1-*The current Program Counter is saved on the stack, low-byte first.
2-*Interrupts of the same and lower priority are blocked.
3-*In the case of Timer and External interrupts, the corresponding interrupt flag is cleared.
4-Program execution transfers to the corresponding interrupt handler vector address.
5-The Interrupt Handler Routine executes.

in MacKenzie book says that the worst case for a interrupt to ocurr with a 12MHZ crystal is 9.25us.

my question is. when executing fase 1-4. can i still work with the 8051 or it stops doing whatever it was doing, and loose those precious and critical 9.25us. or the 8051 works and the next instruction to execute is the fase 5