The Unabridged Pentium 4 IA32 Processor Genealogy

General

There are four types of interrupt-related events that can cause the currently executing program to be interrupted:

• An interrupt request from a hardware device external to the processor is recognized if recognition of external interrupts is enabled (EFlags[IF] = 1).

• The assertion of the processor's NMI input.

• Execution of a software interrupt (INT) instruction.

• Processor detection of a software exception error condition.

When any of these events occurs, the currently executing program is interrupted. In other words, the processor must:

1. Suspend execution of the program.

2. Mark its place for later resumption.

3. Determine the type of request.

4. Jump to an event-specific interrupt service routine (or task) to service the request.

5. Return to the interrupted ...