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From: kirchner@informatik.uni-kl.de (Reinhard Kirchner)
Newsgroups: comp.arch
Subject: 64 Bit addressing on R4000?
Keywords: R4000, 64bit addressing
Message-ID: <8083@uklirb.informatik.uni-kl.de>
Date: 24 Jun 91 13:26:00 GMT
Sender: news@uklirb.informatik.uni-kl.de
Lines: 21


Months ago when the first discussions about the new MIPS R4000 processor
where held here people from MIPS stated ( if I remember well ) that
they will cross the limit of 32 bit addresses and be able to address a
64 bit virtual address space.

Now today I got a data sheet of the R4000 from IDT, and it does not only
say anything about this, it also shows a block diagram with a 32 * 32 bit
register set. So: will the R4000 really have 64 bit addresses and how
can they be generated with 32 bit registers ?

What comes into mind is just pairing them, to get 64 bit, but this would
require extra instrucions, or a mode bit, and would in any case reduce
the amount of usable registers considerably.

Maybe people from MIPS ( Mr. Mashey ? ) could shed some light on this ?

Reinhard Kirchner
Univ. Kasierslautern, Germany
kirchner@uklirb.informatik.uni-kl.de