Path: utzoo!utgpu!water!watmath!clyde!att-cb!att-ih!pacbell!ptsfa!ames!nrl-cmf!mailrus!umix!uunet!mcvax!cernvax!ethz!forty2!poole
From: poole@forty2.UUCP (Simon Poole)
Newsgroups: comp.sys.atari.st
Subject: Re: Changes/fixes to OS
Message-ID: <190@forty2.UUCP>
Date: 7 Mar 88 21:38:25 GMT
References: <2597@crash.cts.com> <7499@apple.Apple.Com>
Reply-To: poole@forty2.UUCP (Simon Poole)
Organization: Exp. Physics University Zuerich
Lines: 30


In article <7499@apple.Apple.Com> landon@Apple.COM (Landon Dyer) writes:
>In article <2597@crash.cts.com>, sreeb@pnet01.cts.com (Ed Beers) writes:
......
>> Atari use the $axxx and $fxxx instruction traps.  These are reserved in the
>
>Line-A was used because, well, Apple used it, and it was there.  Line-F was
>used as an optimization (two-byte JSRs so the AES would fit into ROM), and
>is in no way related to the way the ST is "defined" to the outside world.
..........
>> This probably explains why the megas come with a 68000 rather than a 68020.

>Nope.  The ST is pretty stuck in the mud with respect to the 68000, but for
>different reasons.  Moving to a 68020 will be painful for EVERYONE.

Matter of fact, the german computer magazin c't has published a series
of patches for the ROM's that allow you to run most (they claim 99%)
programs with their 68020 board. They use some of the unused Line-A
"instructions" as replacement for the Line-F trap. The main problem is
that you really don't get so much more speed (they claim about 50%)
for the money (if you can use the 68881 you're naturally lucky).





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UUCP:   ...mcvax!cernvax!forty2!poole			Simon Poole
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