Interrupt flag

IF (Interrupt Flag) is a system flag bit in the x86 architecture's FLAGS register, which determines whether or not the CPU will handle maskable hardware interrupts.

The bit, which is bit 9 of the FLAGS register, may be set or cleared by programs with sufficient privileges, as usually determined by the Operating System. If the flag is set to 1, maskable hardware interrupts will be handled. If cleared (set to 0), such interrupts will be ignored. IF does not affect the handling of non-maskable interrupts or software interrupts generated by the INT instruction.