Table of Contents
What happens to the processor when an interrupt occurs?
When an interrupt occurs, it causes the CPU to stop executing the current program. When it is generated, the processor saves its execution state via a context switch, and begins executing the interrupt handler at the interrupt vector.
How does the processor know who is doing the interrupting?
The processor samples the interrupt input signal during each instruction cycle. The processor will recognize the interrupt request if the signal is asserted when sampling occurs. Level-triggered inputs allow multiple devices to share a common interrupt signal via wired-OR connections.
How does a CPU detects an interrupt?
A hardware chip on the Motherboard, called the ‘interrupt controller’, detects the mouse signal. The interrupt controller issues an interrupt signal and sends it to the CPU. The CPU receives the interrupt signal. CPU re-loads its registers with the original values it stored earlier and carries on with what it was doing …
How does the processor know what code to run when an interrupt occurs?
The CPU uses a table and the interrupt vector to find OS the code to execute in response to interrupts. A software interrupt is shown here. As the computer runs, processing switches between user processes and the operating system as hardware and software interrupts are received.
How are interrupts detected?
How does the system handle an interrupt for an input request from an input device?
If the CPU detects a signal on the interrupt request line, it passes control to the interrupt handler routine. The interrupt handler routine determines the cause of the interrupt, performs the necessary processing, and passes control back to the CPU once processing has been completed.
What is interrupt interrupt signal?
Interrupt is a method by which an i/o device or program communicate with the processor, that it requires the service of processor. It is a signal which may be disturb or alter the sequence of execution of the processor.
What are interrupts in CPU?
Interrupts may be due to Hardware or Software , Example of a software interrupt is divide by Zero , Hardware interrupts may be due to internal or External devices. CPU should stop its present operation, perform instructions contained in ISR, and after completing , it should resume the operations, it was performing prior to executing ISR.
What is interrupt service routine?
Interrupt service routine (ISR) is actually a call back function (program) in case of software or device driver (I/O device) in case of hardware. Interrupt is a method by which an i/o device or program communicate with the processor, that it requires the service of processor.
How do external interrupt controllers work with CPUs?
Some CPUs support external interrupt controllers which have the extra pins and multiplex their signals down to a single pin on the CPU.