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Re: Banked CP/M 3.1 on Apple //e?
- Subject: Re: Banked CP/M 3.1 on Apple //e?
- From: "Steve \"Usotsuki\" Nickolas" <usotsuki@verizon.net>
- Date: Tue, 23 Dec 2003 11:06:34 GMT
- In-reply-to: <P9TFb.62551$aT.50534@news-server.bigpond.net.au>
- Newsgroups: comp.sys.apple2, comp.os.cpm
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RedskullDC wrote:
Things to keep in mind:
Control registers for the memory card(s) will not be in the $C000 space due
to the Z-80's address line translation (Microsoft card anyway, not sure
about some
of the others: Starcard etc.)
For the Softcard, which is what my tools emulate, it is in the 0xE000 space.
Need to ensure that Bank 0 , pages 0 and 1 (6502) are not switched out when
the
6502 'wakes-up' to do a memory refresh.
Hm, and an emulator won't likely emulate that effect, so it would need
to be tested on real hardware...
Likewise, your video routines will need to be smart enough to bring in the
appropriate
memory banks if you are using Apple2e 40 or 80 column mode. Probaby best to
keep track in the BIOS of what bank is currently switched in.
Using a videx or similar 80 column card would be a damn sight easier to
implement
with multiple memory banks.
Heh, prolly. o.o;;;
This does seem a daunting task for me, but perhaps someone else wouldn't
be as daunted by the idea. Quite fortunate that the Softcard was
popular (even if I've never had one of the suckers)... ;)
Good luck,
Red
-uso.