Path: utzoo!mnetor!uunet!seismo!sundc!pitstop!sun!amdahl!apple!bcase From: bcase@Apple.COM (Brian Case) Newsgroups: comp.arch Subject: Re: negative addresses Message-ID: <9485@apple.Apple.Com> Date: 10 May 88 17:57:26 GMT References: <2393@uvacs.CS.VIRGINIA.EDU> Reply-To: bcase@apple.UUCP (Brian Case) Organization: Apple Computer Inc, Cupertino, CA 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)? Check out the Elxsi machine. It has "negative" addressing. It seems that with negative addressing, you can get a simple address checking for free. Put the OS Kernel in negative space, e.g. >...as far as I can tell, the primary (only?) use >of unsigned arithmetic is for address computations. Yeah, same here, unless it's for some obscure purpose or is supported directly by the source language.