Path: utzoo!mnetor!uunet!steinmetz!davidsen
From: davidsen@steinmetz.ge.com (William E. Davidsen Jr)
Newsgroups: comp.arch
Subject: Re: negative addresses
Message-ID: <10769@steinmetz.ge.com>
Date: 10 May 88 14:17:39 GMT
References: <2393@uvacs.CS.VIRGINIA.EDU>
Reply-To: davidsen@crdos1.UUCP (bill davidsen)
Organization: General Electric CRD, Schenectady, NY
Lines: 22

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)?

  "bits is bits," but I suspect that a lot of programs will have trouble
with non-contiguous addressing. Address wrap forces the lowest address
to "follow" the highest address, which may make io interesting.
| 
| Why ask such a question, you ask -- well, I'm trying to remove unsigned
| arithmetic from WM, and as far as I can tell, the primary (only?) use
| of unsigned arithmetic is for address computations. Soooooo...

  My gut feeling is that this is not correct, but I have no metrics at
this time to confirm or deny what you say.
| 
| Bill Wulf

-- 
	bill davidsen		(wedu@ge-crd.arpa)
  {uunet | philabs | seismo}!steinmetz!crdos1!davidsen
"Stupidity, like virtue, is its own reward" -me