interruptslinks

An interrupt is a signal to the processor emitted by hardware or software indicating an event that needs immediate attention. An interrupt service routine (ISR), also known as an interrupt handler, is a software routine that the processor executes in response to an interrupt. When an interrupt occurs, the processor suspends its current task and jumps to the ISR to handle the event. After the ISR completes, the processor typically resumes the interrupted task.

Interrupts are crucial for efficient system operation. They allow the processor to respond to external events, such as a key press or a network packet arrival, without constantly polling for them. Polling would require the processor to repeatedly check for events, consuming significant CPU cycles. Interrupts enable a more responsive and efficient multitasking environment.

There are two main types of interrupts: hardware interrupts and software interrupts. Hardware interrupts are generated by external devices through interrupt request (IRQ) lines. Software interrupts, also known as traps or exceptions, are generated by instructions within a program, often to request services from the operating system or to signal an error condition.

The process of handling an interrupt involves several steps. First, the interrupt signal is detected by the processor. Then, the processor saves the current state of the interrupted program, including the program counter and register values. It then identifies the source of the interrupt and calls the appropriate ISR. The ISR performs the necessary actions to service the interrupt. Finally, the processor restores the saved state of the interrupted program and resumes its execution. This mechanism allows for asynchronous event handling, making systems more dynamic and responsive.