Changes

When any type of interrupt is received, the program counter is typically pushed on the [[Stack|stack]], and then the program counter is loaded from an ''interrupt vector'' stored in a register or a pre-defined memory location, usually at the top of bottom of physical address space. Effectively, this means that a subroutine jump is performed to the interrupt-handling routine. In systems where multiple devices are connected to one hardware interrupt line, it is necessary to poll the PIC/APIC or the attached devices to determine which one(s) triggered the interrupt before servicing the request(s).