Path: utzoo!attcan!uunet!mcvax!enea!tut!santra!jmunkki
From: jmunkki@santra.HUT.FI (Juri Munkki)
Newsgroups: comp.sys.mac.programmer
Subject: Re: Knowing Machine Code
Keywords: 68881 emulator.
Message-ID: <13945@santra.UUCP>
Date: 22 Jun 88 06:31:30 GMT
References: <13735@comp.vuw.ac.nz> <104700032@uiucdcsp> <4760@husc6.harvard.edu> <13542@shemp.CS.UCLA.EDU> <12217@apple.Apple.COM> <8915@dartvax.Dartmouth.EDU> <12256@apple.Apple.COM>
Sender: jmunkki@santra.UUCP
Reply-To: jmunkki@santra.UUCP (Juri Munkki)
Organization: Helsinki University of Technology, Finland
Lines: 13

In article <12256@apple.Apple.COM> dan@apple.apple.com.UUCP (Dan Allen) writes:
>One final thought on emulating the 68881: since the 881 uses a lot of
>the same addressing modes that the rest of the 68xxx family does, an
>emulator would have to disassemble or correctly emulate ALL of the 68xxx
>addressing modes, something that takes LOTS of code to do. 

Even the coprocessor makes the 68020 calculate the addresses. This means that
you should be able to convert the addressing modes into LEA instructions. Of
course a known subset of instructions would be better than nothing.

Juri Munkki
jmunkki@santra.hut.fi
jmunkki@fingate.bitnet