How do interrupts work in CPU processing?

Interrupts are signals sent to the CPU to pause its current task and handle a higher priority task.

In more detail, interrupts are a crucial part of a computer's architecture that allows the CPU to manage multiple tasks efficiently. They are signals sent to the CPU from either hardware or software indicating that an event needs immediate attention. When an interrupt is received, the CPU temporarily stops its current task, saves its state, and begins executing the interrupt handler, a special routine to deal with the interrupt.

There are two main types of interrupts: hardware and software interrupts. Hardware interrupts are generated by hardware devices like a mouse, keyboard, or printer when they need the CPU's attention. For example, when you press a key on your keyboard, it sends an interrupt to the CPU, which then processes the keystroke. Software interrupts, on the other hand, are generated by programs running on the computer. They are used to request services from the operating system, such as reading from a file or sending data over a network.

The process of handling an interrupt is quite intricate. When an interrupt is received, the CPU first completes the instruction it is currently executing. It then saves its current state, including the program counter and register values, so it can resume its task later. The CPU then loads the address of the interrupt handler from the interrupt vector table, a special table in memory that holds the addresses of all the interrupt handlers. The CPU then begins executing the interrupt handler.

The interrupt handler's job is to deal with the event that caused the interrupt. Once it has done this, it issues a return from interrupt (RFI) instruction, which tells the CPU to restore its state and resume its previous task. This process ensures that the CPU can handle multiple tasks efficiently, responding to important events as they occur while still completing its other tasks.

In summary, interrupts are a fundamental part of how a CPU manages its tasks. They allow the CPU to respond to important events quickly and efficiently, ensuring that the computer runs smoothly and responsively.