Path: utzoo!utgpu!attcan!uunet!cbmvax!rutgers!mailrus!ncar!boulder!tramp!walkerb
From: walkerb@tramp.Colorado.EDU (Brian Walker)
Newsgroups: comp.sys.atari.st
Subject: Re: TT TT/X specs (rumour?)
Keywords: Chapel Perilous
Message-ID: <4494@boulder.Colorado.EDU>
Date: 7 Nov 88 09:30:29 GMT
References: <252@cstw01.UUCP> <1216@atari.UUCP> <253@cstw01.UUCP> <2962@sugar.uu.net>
Sender: news@boulder.Colorado.EDU
Reply-To: walkerb@tramp.Colorado.EDU (Brian Walker)
Organization: University of Colorado, Boulder
Lines: 22

In article <2962@sugar.uu.net> peter@sugar.uu.net (Peter da Silva) writes:
>I have a question about TOS on the 68020.
>
>I have been told there are a number of "Line-A" or "Line-F" type traps that
>actually use illegal rather unimplemented opcodes. These opcodes are used for
>real instructions on the 68020.
>
>If this is true, then there is little chance for 68020 TOS. Any comments?

On the 68020, line-F opcodes are used for co-processor operations.  The line-A
opcodes, however, are permanently available for use.  You may note that the
Macintosh uses line-A calls for all of its system calls so line-A is not a
problem.

On the ST, TOS uses the line-F for internal calls.  But that can be changed in
any revision of TOS because those calls are "subject to change without notice."
That, of course, means that Atari may, at their choosing, write a TOS/GEM
implimentation for a 68020 system by moving the line-F calls and performing
some basic rewrites to facilitate operation on a 68020.
Brian Walker, University of Colorado at Boulder|| printf("Say please:] \n");
              walkerb@tramp.colorado.edu=======|| if (say_please(user))
{ncar,nbires,sunybcs}!boulder!tramp!walkerb====||     be_nice(random());