Mail Archives: djgpp/1997/10/08/07:29:11
On Tue, 7 Oct 1997, Gurunandan R. Bhat wrote:
> > (the usual DS selector is made
> > invalid when a signal, such as SIGINT, is pending, while the alias
> > selector is *always* valid, and should therefore be used by interrupt
> > handlers).
> >
>
> Very important advice. Shouldn't this be documented
> somewhere?. If it isn't already that is.
A *lot* of things about hardware interrupts should be documented, because
it's so much of a black art. The question is (a) where? and (b) how do
you get people to read that, instead of posting the same questions all
over again.
There should be a tutorial on writing interrupt handlers. Martynas
Kunigelis once wrote a draft of such a thing (see the pointer in the
FAQ); I'd imagine that this is documented there somewhere. I'd love to
see some continuation to that effort, it seems to me that there are quite
a few people here that have first-hand experience with this.
Barring that, anybody who wants to futz with hardware interrupts, needs to
take a very good lookat the few handlers built into DJGPP (the keyboard
handler for generating SIGINT on ^C and the timer handler for profiling).
If they do, they will see the DS alias used all over the place.
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