Rainier Maas schreef:
> > Hi!
> >
> > I have a little question:
> >
> > - Interrupt occurs
> > -> (DI)
> > -> Interrupt Routine (-> new interrupt occurs)
> > -> EI
> > -> ret
> >
> >
> > What will happen if a NEW interrupt occurs when the MSX is
> > processing obove mentioned "routine-part"?
> >
> > - After switching the interrupts on, will the MSX remember the
> > interrupt and calls again the interrupt-routine?
> >
> > OR:
> >
> > - Is the additional interrupt lost forever?
>
> Hi
>
> I think the interrupt will be lost forever since all interrupts are
> disbled by DI. I know for sure it wont be remembered.
>
> I don't know what kind of interrupt routine you are using but it is
> possible that an EI is in there (e.g. when you use a bios call an EI
> is almost always in there). In that case the new interrupt will occur,
> and your interrupt routine will be called when it is still in the
> process of handling the previous interrupt. As you can imagine your
> msx will crash in this scenario due to the exponential growth of the
> heap etc. etc.
>
> HTH
>
I don't know it exatcly anymore
but when you enter an interupt routine the interupt flag will be set
this flag will hold other interupts untill its resets
you always have to end and interupt routine with RETI and not with RET
But there must be people on this list who can explain it perfectly.
Erik
--
****
MSX Mailinglist. To unsubscribe, send an email to [EMAIL PROTECTED] and put
in the body (not subject) "unsubscribe msx [EMAIL PROTECTED]" (without the
quotes :-) Problems? contact [EMAIL PROTECTED] (www.stack.nl/~wiebe/mailinglist/)
****
