Interrupt Vector Table

Interrupt Vector Table
A table for the interrupt vectors in the memory. The table facilitates the servicing of the multiple interrupting sources for each internal device. In each row for an interrupt vector address, there are bytes to provide the corresponding interrupt service routine address.

Maskable Interrupt

Maskable Interrupt
A source, which can be disable or masked.

Non-Maskable Interrupt

Non-Maskable Interrupt
A source, which cannot be disable and is used for most needed service cases. 

Interrupt Flag

Interrupt Flag
A register bit for a Boolean variable that sets to signal a need for executing an interrupt service routine(ISR) . It resets when a corresponding ISR starts executing. 

Interrupt Mask Bit

Interrupt Mask Bit
When a bit is reset (=false ) the request for the initiation of interrupt service is responded, otherwise it is not responded. 

Interrupt Enable Bit

Interrupt Enable Bit 
If sets true it enables the interrupts from a sources.

Foreground Program

Foreground Program 
Foreground program is one that is executed when no interrupt call is being serviced.