GATE CSE 1995 | Question: 1.3

Question

In a vectored interrupt:

• A. The branch address is assigned to a fixed location in memory

• B. The interrupting source supplies the branch information to the processor through an interrupt vector

• C. The branch address is obtained from a register in the processor

• D. None of the above

Comments

option A : gives definition of non-vectored interrupt 

option B : gives definition of vectored interrupt 

option C : gives defintion of Register Indirect Addressing 

Answer 1

Answer: B

A vectored interrupt is a processing technique in which the interrupting device directs the processor to the appropriate interrupt service routine. This is in contrast to a polled interrupt system, in which a single interrupt service routine must determine the source of the interrupt by checking all potential interrupt sources, a slow and relatively laborious process.

Comments

I'm a little confused. Below is from Hamacher:

A commonly used scheme is to allocate permanently an area in the memory to hold the addresses of interrupt-service routines. These addresses are usually referred to as interrupt vectors, and they are said to constitute the interrupt-vector table. 

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@Manu Thakur Sir,

I think both $vector$ $address$. and $interrupt$ $vector$ are same terms.

https://en.wikipedia.org/wiki/Vectored_interrupt

https://www.sciencedirect.com/topics/engineering/interrupt-vector

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Pranavpurkar, yes, you are correct !!

Answer 2

Vector interrupt basically gives the flexibility of  multiple branches.It not gives a fixed address and go to that location and service interrupt . Rather it goes to different location , where interrupt servicing is required.

So,(A) is definitely false . As it concerns with a fixed location

(C)Branch address is obtained from the device which finds an interrupt and told processor to service it . Processor generates an ISR with Branch address , which can service that interrupt and some other interrupts too

(B) The interrupt source supplies branch information to the processor by device specified interrupt vector . link :http://www.cse.iitm.ac.in/~vplab/courses/comp_org/Input_Output_Organization_11.pdf

So, Ans B)

Comments

Please check what you have written 🙏

Answer 3

After Reading this definitely you will select option (b). :)

https://www.quora.com/What-is-the-difference-between-a-vectored-and-a-non-vectored-interrupt

Comments

Why c is false?

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@sathvikchiramana here CPU does not know address in advance as no branch address is supplied by interrupting source so vectored interrupt is not possible here.

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thankyou @krishn.jh

Answer 4

Vector interupt --> In vector interupt i/o or device send interupt + address of ISR.

 

so B is correct