Re: GS/OS and IRQs - strange thing

[dempson@swell.actrix.gen.nz (David Empson)]

In article <1993Apr9.223658.15456@ifi.unizh.ch> gudat@avalon.physik.unizh.ch (gudat henrik) writes:
>  
> When I call this routine at 01FC88 within a heartbeat task, the program
> crashes at 01FC8C (+/-2).

Hm, weird.  I can't see anything in the GS/OS manual that says you
can't post a signal from a heartbeat task, but there is a note on page
272 which says that GS/OS uses a heartbeat task to execute pending
signals.  I can't see how that would have any bearing on the problem,
though.

Have you checked that GS/OS is active before trying to call SIGNAL?
Heartbeat interrupts might be executed under ProDOS-8 as well, and the
code that the JMP points to isn't there any more.

If the ROM was switched in for some reason, you'd have difficulty
calling SIGNAL.

> BTW: I think I've read somewhere that the quarter second IRQ is
> reserved for AppleTalk. Is that correct and/or should I use another
> one??

Yes, AppleTalk uses the 1/4 second interrupt for timing.  I don't know
how GS/OS's interrupt handlers interact with ones which hook directly
into the vector, but if you did hook in, you'd have to make sure you
weren't preventing AppleTalk from getting the interrupt.

It's probably safer to use something else.
-- 
David Empson                                                               
dempson@swell.actrix.gen.nz    <--- Note my new E-Mail address!            
Snail mail: P.O. Box 27-103, Wellington, New Zealand