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From: jms@tardis.Tymnet.COM (Joe Smith)
Newsgroups: comp.sys.amiga,comp.sys.amiga.tech
Subject: Re: 680x0 vs 68000
Summary: Not downward compatible
Keywords: 68020 68010 processor replacement
Message-ID: <1187@tardis.Tymnet.COM>
Date: 23 Aug 90 08:35:15 GMT
References: <453@krabat.marco.UUCP> <K=#%MJ$@rpi.edu> <15802@s.ms.uky.edu>
Reply-To: jms@tardis.Tymnet.COM (Joe Smith)
Followup-To: comp.sys.amiga
Organization: BT Tymnet, San Jose, CA
Lines: 19

[Note that I have removed alt.sources.amiga from this crossposting.]

In article <15802@s.ms.uky.edu> phoenix@ms.uky.edu (R'ykandar Korra'ti) writes:
>  As for incompatiblity; yes, only as far as the 68020 is also incompatible.
>  Programmes that will run on a 68020 will run on a 68010.
>                                                      - R'ykandar.

This is incorrect.  Programs that were compiled to run on a 68020 will NOT
run on a 68010 or 68000 because the 68020 uses some opcodes that are
illegal on the earlier processors, and the 68020 has new addressing modes
that the 010 and 000 don't even notice.

Programs that were developed on a 68020 will run on a 68000 as long as the
programmer tells the compiler to use 68000 compatible binaries.
-- 
Joe Smith (408)922-6220 | SMTP: jms@tardis.tymnet.com or jms@gemini.tymnet.com
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