> > >I want to speed up the interrupt (original #38).
> > >So I use the #FD9A for jumping to my own routine (which will
> > >pop the return-adress from the stack), checking the Vertcal-
> > >Blank flag and only the absoult necessary things.
> >
> > There is a much more convenient way of doing this: select RAM in the
> > #0000-#3FFF area and write your own interrupt handler at #38.
>
> I thought to get problems by using the DOS2-mapper routines if
> ROM isn't selected in page 0.
I never tried to keep my custom BIOS operating during disk actions.
If I wanted to do that, I would have to program a lot of subroutines
apart from the interrupt handler. (ENASLT, CALSLT etc.)
During disk actions, you don't really need an efficient interrupt
handler, because interrupts will be disabled most of the time anyway.
Simply switch to ROM for disk actions and back to RAM afterwards.
To turn off the drive, you can use the trick Nyyrikki described,
although it is not 100% nice. He uses the default address for the
disk motor counter, but it is not guaranteed that the counter will be
there. There is a more safe way, I will look it up.
Note that I have never seen a machine on which his trick doesn't
work, but I haven't seen every single MSX model so there might exist
one.
I once made a very compatible way of stopping diskdrive motors. It
worked too well: on some harddisk interfaces, it stopped the harddisk
from spinning! I think it did stop the harddisk on Novaxis, but
didn't stop it on a Bert.
Bye,
Maarten
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