Date: Tue, 29 Nov 94 22:35 GMT
From: mjo AT mrao DOT cam DOT ac DOT uk (Martin Oldfield)
To: dj AT stealth DOT ctron DOT com
Cc: nigel AT algor DOT co DOT uk, djgpp AT sun DOT soe DOT clarkson DOT edu, trav AT clark DOT edu
Subject: Re: Interrupts

>>>>> "DJ" == DJ Delorie <dj AT stealth DOT ctron DOT com> writes:

    >> > One other problem is that you can't do anything in a real
    >> mode > callback (or interrupt) that might cause a mode switch.
    >> Basically, > you can do integer math and maybe call a function
    >> or two - it's pretty > limited.  It may work sometimes, but
    >> it's not guaranteed.
    >> 
    >> What happens if the real-mode callback/interrupt handler page
    >> faults?

    DJ> Unknown.  In non-dpmi mode, go32 handles it correctly,
    DJ> excepting DOS reentrancy issues.  In DPMI mode, you're
    DJ> supposed to lock it.  1.12 allows the locking call in all
    DJ> modes, but only honors it in DPMI mode, and V2 honors it
    DJ> always.


So does that mean that if I'm running a 1.12 program in non-dpmi mode
and I get an interrupt go32 will check that my handler's paged in (and
if it isn't, page it in) before jumping to it ?

Cheers,

Martin Oldfield, MRAO, Cavendish Labs, CAMBRIDGE, CB3 0HE
Work:  0223 337365 Fax: 0223 354599
The worst sin towards our fellow creatures is not to hate them, but
to be indifferent to them: that's the essence of inhumanity - Shaw