Re: [PATCH] NMI trap revised (was Re: NMI errors in 2.0.30??)

Martin Mares (
Thu, 8 May 1997 17:35:49 +0200


> I was following the NMI discussion and today I have fond, under a pile of
> old DDJ issues, an old manual which explain something (really not much)
> about NMI on the old 80286 PC/XT. Supposing the NMI mechanism is not
> changed for (23456)86, this is a patch that can help detect if the NMI is
> a real hardware failure or triggered by something else.

The NMI status bits certainly didn't exist on the XT as XT has its keyboard
disable bit here. But it should exist on the AT and all newer PC's. Intel Triton
documentation mentions the status bits, too, although AMD 640 Chipset docs
don't (but they miss the 0x61 register at all).

I'll test it today and let's see if the bits work or not.