Non vectored interrupt.

Question

In non vectored interrupt, the address of ISR is

a) assigned to fixed memory location

b) obtained from interrupt vector table

c) none of the above

Comments

https://gateoverflow.in/32835/non-vectored-interrupts

Answer 1

Option (a) : All the non vectored interrupts will be assigned 1 common fixed address which is hardcoded... After executing sequence of instructions there, it will find which device has generated the interrupt. Correct me if I'm wrong.

Answer 2

Answer will be option  C

 in the case of a non-vectored interrupt, the peripheral itself provides the address of the interrupt service routine directly to the processor. This requires more time for an interrupt to be serviced, since the address must be retrieved from the interrupting device every time the interrupt is triggered.

Comments

What you told is true for vectored interrupt where the IO device itself provides the address of the ISR. Here in non vectored I think the answer should be a) but it's given b)

---

no , I am telling  here about non vectored interrupt  . i/o connections can be done with processor by three modes .

1. Programmed IO

2. Interrupt IO

3.DBA

 and in programmed IO mode devices are directly  connected with cpu . and cpu will get to know about interrupt  by  its software  called "device driver".  

and here  System bus will provide interface between  device driver and IO .

for ex- printer

now read my answer

---

Vectored Interrupt: Device provide address of IVT(Interrupt vector Table) then using that processor determine the address of ISR.

Non-Vectored Interrupt: Device provide the address of ISR directly to processor, there is no need of IVT in this case.

Now coming to question, since in non-vectored device provide address of ISR directly it must know the address of ISR, that's why it is assigned to a fixed memory location.

So answer should be A.