Date : Fri, 31 Jan 1997 02:06:51 +0000 (GMT)
From : Chris Evans <chris@...>
Subject: Re: BBC emulation (what else...)/coding help offer/etc.
On Thu, 30 Jan 1997, David Ralph Stacey wrote:
> Chris wrote:
>
> > I'm trying to find ANY PC Beeb emulator that is capable of running the
> > classic Exile. I run both Win95 and Linux. Here's the results:
> >
> > Xbeeb (0.3.6) -- Looks very promising. But running Exile bombs with
"can't
> > find $.ADFS in disk catalogue" or similar. And by bombs, I mean the whole
> > program quits, not some "Not found" from the BBC. This occurs with "*RUN
> > EXILEL"
>
> Humm... This shouldn't be happening. I suspect that you're trying to
run Xbeeb
> without XDFS. Basically, the XDFS ROM does some nasty things behind
your back
> to get things like Exile working. Quite a few games (eg. disc versions of
> Pipeline, Spellbinder, Elite, etc) won't even load without it, and it does
> silly things to make the emulator more stable. Make sure it's #define-d.
Error: File $.ADFS not found in EFS catalog
Nope XDFS is there. Quite likely though, I've been inept in my attempt to
get a __CATALOG__ from a load of files I found in a zip. Weird that ADFS
is invoked and moaned about -- other beeb emulators find other things to
crash on :)
> Even then, XDFS is a DFS emulator - it isn't supposed to cope with *ADFS
> commands. Try running the 5.25 disc version instead - you'll need to
strip the
> protection first though ;-)
Ah the good old days. I did that once long ago -- a minor hassle, having
to write your own disassembler, follow de-encrypting routines etc :-) I
seem to remember the classic disk protection was to make a bad sector on
the disk and make sure it was there before booting.
Check out Exile.zip I have lying around in
ftp://ftp.lmh.ox.ac.uk/users/chris/Exile.zip. If you have a more stable
version of Exile feel free to mail it to me or put it up for ftp. Disk
protection included if you want -- I'll happily re-remember my 6502 and
low level disk sector commands for the sake of getting the game to run
once more!
> and recompile. This should get Exile (sort of) running under Xbeeb
0.3.6, but
> the timers will be wrong.
You have it going???! Drool etc.
Want a hand with any coding? I'm thinking an i386 assembly hand optimised
6502 instruction decode routine would have things melting along. Perhaps
leaving a fair bit more free CPU to emulate timers etc. more reliably.
Also I'd be interested in getting the thing going with DGA for raw vido
performance.
> Also you won't be able to load and save your position - you'll have to wait
> for XDFS 0.90 for that - should be in the next release of xbeeb, but
if you're
> desperate mail me and I'll send you a beta test version.
Well I remember the save mechanism worked by stuffing a page of memory at
$400 (or was is $900). I'm sure I could code a way to get that out to
disk.
> Hope this helps,
>
> Dave Stacey - author of XDFS.
Oh one last point: what is the proper way of transferring a load of files
in a directory, into an XDFS suitable format? I always seem to get one or
more files trashed (first one in __CATALOG__, perhaps that is causing my
filesystem problems above).
Cheers,
Chris.