When the processor under execution is interrupted by a non-maskable interrupt it serves?

What action is taken when the processor under execution is interrupted by TRAP in 8085MPU?

Processor serves the interrupt request after completing the execution of the current instruction.

How long can the INTR signal stay high?

The INTR pulse can remain high until the interrupt flip-flop is set by the EI instruction in the service routine. If it remains high after the execution of the EI instruction, the processor will be interrupted again, as if it were a new interrupt.

What is the use of interrupt vector?

An interrupt vector is the memory address of an interrupt handler, or an index into an array called an interrupt vector table or dispatch table. Interrupt vector tables contain the memory addresses of interrupt handlers. When an interrupt is generated, the processor saves its execution state via a context switch, and begins execution of the interrupt handler at the interrupt vector.

What happens when halt instruction is executed?

The processor stops and goes to the halt state. If an interrupt occurs, it responds and then continues execution.

What is difference between vectored and non vectored interrupts?

Vector interrupt --> when processor directly call the respective isr when interrupt occurs so, address of respective isr is usually save in register. Non interrupt Vector --> In this case when interrupt occurs the processor calls a generic isr and in generic isr uaer has to call respective isr by checking status register.

What is interrupt vector?

When a processor is interrupted to do a particular task,Program counter should be loaded with the the address of subroutine(task).If the processor automatically generates the address then it is known as vectored interrupt.for example if 8085 microprocessor is interrupted through RST 5.5 pin,then processor multiplies 5.5 by 8 and converts it to Hex address.If user has to provide address of subroutine using CALL instruction then it is known as non vectored interrupt

How are multiple interrupts dealt with?

There are 2 approaches to handle this situation,1.Disable interrupts while an interrupt is being processingin this approach, when the processor is being processing an interrupt, the processor ignores any new interrupt signal and these new signals have to wait in a queue and processor will check after the currently processing interrupt is finished.2. Defining priorities for interruptsin this case, each interrupt has a priority value. When the processor is being executing an interrupt, another interrupt can interrupt and gain the processor if the second interrupt has a higher priority than first oneSource- William Stallings, operating systems Sorry, the word you are looking for is not in the Database

Highest priority interrupt in micro processor?

The highest priority interrupt in a microprocessor is usually the reset interrupt. When a reset occurs, the microprocessor is forced to stop its current operations and begin executing the reset routine. This is critical for initializing the processor and setting it to a known state before starting normal operations.

What is interrupt flag?

Interrupt flags are used to interrupt the processor on what it is doing. When the flag is triggered the processor stops what it is doing attends what the flag wants to get done and once that is done it goes back to what it was doing. It is very useful for detect bug.

What is an Interrupt Give two examples of an Interrupt?

Interrupt is nothing but according to the priority of ur instruction the processor will assign memory to it and will keep the bus line busy .

List and briefly define two approaches to dealing with multiple interrupts?

The discussion so far has only covered the occurrence of a single interrupt. Suppose, however, that multiple interrupts can occur. For e.g. a program may be receiving data from a communication line and printing results. The printer will generate an interrupt every time that it completes a print operation. The communication line controller will generate an interrupt every time a unit of data arrives. The unit could either be a single character or a block, depending on the nature of the communications discipline. In any case, it is possible for a communications interrupt to occur while a printer interrupt is being processed. Two approaches can be taken to deal with multiple interrupts. The first is to disable interrupts while an interrupt is being processed. A disabled interrupt simply means that the processor can and will ignore that interrupt request signal. If an interrupt occurs during this time, it generally remains pending and will be checked by the processor after the processor has enabled interrupts. Thus, when a user program is executing and an interrupt occurs, interrupts are disabled immediately. After the interrupt handler routine is completed, interrupts are enabled before resuming the user program and the processor checks to see if additional interrupts have occurred. This approach is nice and simple, as interrupts are handled in strict sequential order (Figure3.10 (a)). The drawback to the preceding approach is that it does not take into account relative priority or time-critical needs. For e.g. when input arrives from the communications line, it may need to be absorbed rapidly to make room for more input, If the first batch of input has not been processed before the second batch arrives, data may be lost. A second approach is to define priorities for interrupts and to allow an interrupt of higher priority to cause a lower-priority interrupt handler to be itself, interrupted. As an example of this second approach, consider a system with three I/O devices: a printer, a disk, and a communications line, with increasing priorities of 2, 4, and 5, respectively. A user program begins at t=0. At t=10, a printer interrupt occurs; user information is placed on the system stack and execution continues at the printer interrupt service routine (ISR). While this routine is still executing, at t=15, a communications interrupt occurs. Because the communications line has higher priority than the printer, the interrupt is honored. The printer ISR is interrupted, its state is pushed onto the stack, and execution continues at the communications ISR. While this routine is executing, a disk interrupt occurs (t=20). Because this interrupt is of lower priority, it is simply held and the communications ISR runs to completion. When the communications ISR is complete (t=25), the previous processor state is restored, which is the execution of the printer ISR. However, before even a single instruction in that routine can be executed, the processor honors the higher priority disk interrupt and control transfers to the disk ISR. Only when that routine is complete (t=35) is the printer ISR resumed. When that routine completes (t=40), control finally returns to the user program.

When devices interrupt occurs how does the processor determine which device issued the interrupt?

It's pretty simple. First, the processor must determine which interrupt occurred. On simple hardware setups, you may already know this just by which interrupt handler was called. On more complex hardware, you may have to read status registers in the interrupt controller. Second, the processor has to look up which devices are capable of asserting that interrupt. On simple hardware, generally there is only one device that can trigger each interrupt and this is determined by the way the device is wired. On more complex devices, this may be determined by software and the processor may have to consult tables that were created during the boot process. Third, the processor must determine which of those devices actually asserted the interrupt (if there's more than one). This is typically done by the driver for each device which generally just asks the device if it triggered an interrupt. Most devices have status registers that either directly tell you whether it caused an interrupt or tell you whether the device needs service which was the point of the interrupt anyway.