Interrupt

When the CPU detects an interrupt signal, it stops activity of current and jumps to a special routine, known an interrupt handler. This handler then detects why the interrupt occurred and takes the suitable action. When the handler is over executing this action, it jumps back to the interrupted procedure.

Various levels or "types" of interrupts are supported, from 0 to 255 range. Each type has a booked memory location, known an interrupt vector. The interrupt vector points to the suitable interrupt handler. When 2 or more interrupts occur at the same time, the CPU utilize a priority system The 256 priority levels supported by the Intel 8086-processors may be split into 3 categories:

• Internal Hardware-Interrupts
• External Hardware-Interrupts
• Software Interrupts