INT 02h (2) Non-Maskable Interrupt (NMI)
Generated whenever a non-maskable condition, such as a memory parity
error, occurs.
The default INT 2 handler displays PARITY ERROR 1 if there is a memory
parity error on the system board, or it displays PARITY ERROR 2 if
there is a memory parity error on the I/O channel memory. The handler
will then attempt to find the location of the error. If the error is
found, the segment address of the error is displayed; otherwise,
'?????' is displayed. In either case, the machine then goes into an
indefinite loop and is disabled until the power is turned off and back
on.
This is the only interrupt that cannot be masked out by the CLI
instruction (Clear Interrupts).
Notes: The PC Convertible has the Non-Maskable Interrupt
attached to the diskette, real-time clock, keyboard,
and the system suspend interrupts.
The PCjr has the Non-Maskable Interrupt (NMI)
attached to the keyboard interrupt.
The math coprocessors generate this interrupt when
an error is encountered. The 8087 directly executes
this interrupt when an error occurs, whereas the
80287 and 80387--to maintain software compatibility
with the 8087--call the IRQ 13 interrupt handler,
which in turn calls INT 2.
This page last updated on Fri Nov 30 10:49:50 MSK 2001
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