pete@stc.UUCP (10/18/85)
Put briefly, I need to know how I can find the address of
the current DMA area.
Expansion:
I'm running CP/M-80 Ver. 2.2. This enables me to set the DMA to
anywhere I like; fair enough, there's a system call for it
(26). But I can't find any way to set it back to what it was
before, only the default at 80H.
The reason I want to do this is that I'm designing a print
spooler for my home system, a Gemini Multi-Board system,
using an area in my RAM-disk for the spool file(s) and
interrupts from a real-time clock to drive the despooling.
Now, sooner or later my interrupt routine is going to want
to read a sector from the RAM-disk when an application
program has set the DMA address to somewhere other than the
default area. If I restore the DMA address from that used by
the despooler to the default - Blooey!!
I can't find this data in my Digital Research manuals.
Any help would be very welcome.
If there is a lot of interest, I'll summarise to the net.
Many thanks,
--
Peter Kendell <pete@stc.UUCP>
...mcvax!ukc!stc!pete
'Only too far is far enough'