Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!swrinde!zaphod.mps.ohio-state.edu!tut.cis.ohio-state.edu!att!occrsh!uokmax!norlin
From: norlin@uokmax.ecn.uoknor.edu (NARC ONE)
Newsgroups: comp.sys.atari.8bit
Subject: Re: 130XE Memory tricks
Message-ID: <1989Dec12.151901.23150@uokmax.ecn.uoknor.edu>
Date: 12 Dec 89 15:19:01 GMT
References: <19168@watdragon.waterloo.edu>
Reply-To: norlin@uokmax.UUCP (NARC ONE)
Distribution: na
Organization: University of Oklahoma, Engineering Computer Network, Norman, OK
Lines: 33

In article <19168@watdragon.waterloo.edu> rrwood@lotus.waterloo.edu (Roy Wood) writes:
>       Bit zero of $D301 controls whether the upper 16k of the machine is
>ROM or RAM, and I can turn it off and on without any problem.  However,
>I tried to do the following:
>
>1) copy the ROMs down to lower memory.
>2) swap out the ROMs for RAM.
>3) copy the "ROMs" from low memory back to their original position,
>   and thus have the OS completely in RAM.
>
>I took care to mask out all the interrupts I could think of (SEI, POKMSK at
>$10 and it equivalent hardware register, plus the NMI hardware register).

Hm, there was an article in ANALOG about 2/3 years ago that did this very
thing.  I remember typing in the source code, and it worked.  Are you sure
that you disabled NMI's by setting $D40E to zero?  Also, as I seem to
recall (though I'm not sure), you may need to JMP to $E454 to continue
where you left off instead of just switching the O.S. back in.

>(I have a downloaded file version of Mapping the Atari, but it's not very
>complete.)

Wow!  I can hardly find the book version, and have never heard of a file
version.  Could you post/email?

>Thanks...
>
>-Roy Wood (rrwood@lotus.waterloo.edu)

-- 
Norman Lin

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