Upon activation of an interrupt, the microcontroller goes through the following steps 1. It finishes the instruction it is executing and saves the address of the next instruction (PC) on the stack 2. It also saves the current status of all the interrupts internally (i.e: not on the stack) 3. It jumps to a fixed location in memory, called the interrupt vector table, that holds the address of the ISR this is available in mazithi's book's,look at the highlighted case,if not in the stack where it ll be saved
It simply means that the related Flags in the SFRs are set. TF0 flag for Timer0, TF1 flag for Timer1 and so on....