On receiving an interrupt on NMI line, the microprocessor executes INT.This is a non-mask-able, edge triggered, high priority interrupt.Its ISR address is obtained by the microprocessor from location n x 4 in the IVT. These interrupts are invoked by writing the instruction INT n.ISRs for these interrupts are written by the users to service various user defined conditions.
Interrupt vector table emu8086 software#
Interrupt vector table emu8086 code#
The interrupt vector (or interrupt pointer) table is the link between an interrupt type code and the procedure that has been designated to service interrupts associated with that code.Hence all 256 interrupts can be invoked by software.Ĩ086 is interrupted when some special conditions occur while executing certain instructions in the program.Įxample: An error in division automatically causes the INT 0 interrupt. These interrupts are caused by writing the software interrupt instruction INT n where ‘n’ can be any value from 0 to 255 (00H to FFH). 8086 has two pins to accept hardware interrupts, NMI and INTR. These interrupts occur as signals on the external pins of the microprocessor. There are three sources of interrupts for 8086:.The microprocessor services it by executing a subroutine called Interrupt Service Routine (ISR). An interrupt is a special condition that arises during the working of a microprocessor.