Intel IA-32 - Manual (Page 240)

5-64 Vol. 3A
INTERRUPT AND EXCEPTION HANDLING
Interrupts 32 to 255—User Defined Interrupts
Exception Class Not applicable.
Description
Indicates that the processor did one of the following things:
•
Executed an INT n instruction where the instruction operand is one of the vector numbers
from 32 through 255.
•
Responded to an interrupt request at the INTR pin or from the local APIC when the
interrupt vector number associated with the request is from 32 through 255.
Exception Error Code
Not applicable.
Saved Instruction Pointer
The saved contents of CS and EIP registers point to the instruction that follows the INT n
instruction or instruction following the instruction on which the INTR signal occurred.
Program State Change
A program-state change does not accompany interrupts generated by the INT n instruction or
the INTR signal. The INT n instruction generates the interrupt within the instruction stream.
When the processor receives an INTR signal, it commits all state changes for all previous
instructions before it responds to the interrupt; so, program execution can resume upon returning
from the interrupt handler.