Mail Archives: djgpp/2000/01/31/09:17:50
On Sun, 30 Jan 2000, JP Morris wrote:
> Ah, but in certain circumstances DOS4GW and it's ilk will only
> operate if they receive IRQs revectored to something strange like
> 0x80 onwards.
CWSDPMI also reprograms the PIC to move the IRQs up, but it tries
several possible values until it finds one that is available. See the
function init_controllers in the file exphdlr.c in CWSDPMI sources.
If you have Turbo C, you could play with that code and see if some
changes help. (If you do that, please report the results to Charles
Sandmann, so he could make the next CWSDPMI release better.)
However, this reprogramming of the PIC is transparent for the
applications, at least in my experience.
> First, Allegro.
> At first I assumed it was an Allegro problem so I went through
> each block of the sound driver code and inserted printf statements
> except for the IRQ handler, which I made count the number of times
> it was called.
>
> This was always 0, except when another sound card was installed, or
> PMODETSR is used instead of CWSDPMI.
> This shows that the IRQs are not reaching the handler, except when
> PMODETSR is used.
This seems to imply that the card and/or the driver do something
strange with the interrupts. I don't know enough about Allegro's
sound code to make a more intelligent guess. Anyone?
Just to make sure whether this is or isn't an IRQ problem, you could
try to connect some other device to the same IRQ 5, and see if the
handler gets the interrupts.
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