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From: navas@cory.Berkeley.EDU (David C. Navas)
Newsgroups: comp.sys.amiga.hardware
Subject: Re: 68040 vs RISC
Message-ID: <21721@pasteur.Berkeley.EDU>
Date: 3 Feb 90 04:12:24 GMT
References: <1990Feb2.073513.29698@agate.berkeley.edu> <21699@pasteur.Berkeley.EDU>
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Reply-To: navas@cory.Berkeley.EDU.UUCP (David C. Navas)
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In article <21699@pasteur.Berkeley.EDU> lachesis@nyquist.bellcore.com writes:
>In article <1990Feb2.073513.29698@agate.berkeley.edu> laba-3en@web-1c (Raja S Kushalnagar) writes:
>>The Motorola 68040, if what I've been reading about here is to be believed,
>>has almost been able to surmount the difficulties of deep pipelining, though
>>it seems not to have surmounted the issue of efficient window register 
>>meshing, and probably might not be able to get over it at all, unless it 
>>goes more the RISC way, which it already seems to be going towards, but while
>>retaining all the advantages of CISCs.  If that can be done, it should really
>
>I beg to differ.  During a study of MIPS vs. RISC by DEC's WRL, it was found
>that a better compiler will *always* do better for code by using a large
>register set instead of wasting all that register space using a register
>window system.

   Yep, I've heard similarly.

   In reality, I'm sure there are just as many people that think that 
   register windowing is a good thing, as there are people that think
   the entire idea is a bit flakey.  [For interested parties, I belong
   to the latter.]

   To answer a question of Raja's...  The 68040 is *not* pin compatible
   for several reasons, most of which have to do with the fact that they
   no longer support external FPU/MMUs...  [They don't have to...]

   Byte has a very interesting, but brief, article about the 68040.
   The magazine also has some very nice things to say about the Amiga
   in it...  AMAZING!!!  Well worth the read, I think...

David Navas
navas@cory.berkeley.edu