Path: utzoo!mnetor!uunet!husc6!bloom-beacon!oberon!bbn!rochester!udel!burdvax!psuvax1!gondor.cs.psu.edu!przemek
From: przemek@gondor.cs.psu.edu (Przemyslaw Klosowski)
Newsgroups: comp.arch
Subject: Re: negative addresses
Message-ID: <3583@psuvax1.psu.edu>
Date: 11 May 88 01:12:27 GMT
References: <2393@uvacs.CS.VIRGINIA.EDU>
Sender: netnews@psuvax1.psu.edu
Reply-To: przemek@gondor.cs.psu.edu (Przemyslaw Klosowski)
Organization: Penn State University
Lines: 14

In article <2393@uvacs.CS.VIRGINIA.EDU> wulf@uvacs.CS.VIRGINIA.EDU (Bill Wulf) writes:
>Has anyone ever seen a machine with "negative addresses", that is, one
>where the address space is -2**31..2**31-1 rather than 0..2*32-1??
>Any thoughts on what the problems with such a scheme might be (or are)?
>
For one, all those nice addressing modes with index scaled by the size of the
data structure:
	EA = (base) + (index)<<(ln2 size)
won't work, unless index is restricted.



				przemek@psuvaxg.bitnet
				psuvax1!gondor!przemek