Question

After RETI instruction is executed then the pointer will move to which location in the program?

(a) next interrupt of the interrupt vector table

(b) immediate next instruction where interrupt is occurred

(c) next instruction after the RETI in the memory

(d) none of the mentioned

I have been asked this question in an interview.

The origin of the question is Interrupt Programming topic in division 8051 Microcontroller of Microcontroller

Answer 1

Right choice is (b) immediate next instruction where interrupt is occurred

The best I can explain: When the RETI instruction is executed, PC will fetch 2-bytes (address) from top of stack which is stored when interrupt is occurred. This will return to the place where interrupt is occurred and starts executing instructions.