Placeholder CPU knowledge - Interrupt Handling | SINSMART

CPU knowledge - Interrupt Handling

Interrupt handling is a crucial aspect of modern computer system architecture, and is a mechanism by which the CPU can be informed of an event that requires its attention. Interrupts are signals generated by peripheral devices, such as a keyboard, mouse, or network card, to indicate that they require the CPU's immediate attention.

In a computer system, the CPU continuously executes instructions in a sequential manner, performing a set of operations on data stored in memory. However, when a peripheral device needs the CPU's attention, it generates an interrupt signal, which causes the CPU to temporarily stop executing the current instruction and instead, handle the interrupt.

Here's how the CPU handles an interrupt:
 
  1. Interrupt request: The peripheral device generates an interrupt request by sending a signal to the interrupt controller, which is responsible for managing the interrupt signals. The interrupt controller determines the priority of the interrupt and sends an interrupt request to the CPU.
  2. Interrupt acknowledgment: The CPU responds to the interrupt request by acknowledging it and sending a signal back to the interrupt controller, indicating that it has received the request.
  3. Saving the current state: The CPU then saves the current state of its registers, program counter, and other important information in a stack or memory, so that it can resume its previous task after handling the interrupt.
  4. Vector fetch: The CPU fetches the interrupt vector, which is a memory address that points to the interrupt handler, a small routine that handles the specific interrupt.
  5. Interrupt handler execution: The CPU jumps to the interrupt handler and starts executing the code in it. The interrupt handler performs the necessary operations to handle the interrupt and communicate with the peripheral device.
  6. Interrupt completion: After the interrupt handler has finished executing, the CPU restores the saved state from the stack or memory, and resumes execution of the instructions where it left off.

It's important to note that interrupts can be either hardware-generated or software-generated. Hardware-generated interrupts are triggered by external devices, such as a keyboard or mouse, while software-generated interrupts are triggered by software routines, such as system calls or exceptions.

In conclusion, interrupt handling is a crucial aspect of computer systems that allows the CPU to handle multiple events and tasks efficiently and simultaneously. By temporarily halting its current task, the CPU can attend to important events that require its attention, and then resume its previous task once the event has been handled.

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