Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10 5/3/83; site pyuxss.UUCP Path: utzoo!watmath!clyde!burl!ulysses!mhuxl!mhuxm!pyuxww!pyuxss!aaw From: aaw@pyuxss.UUCP (Aaron Werman) Newsgroups: net.arch Subject: Re: Complement Arithmetic, -0 as a tag Message-ID: <262@pyuxss.UUCP> Date: Wed, 1-Feb-84 10:41:07 EST Article-I.D.: pyuxss.262 Posted: Wed Feb 1 10:41:07 1984 Date-Received: Tue, 7-Feb-84 08:23:40 EST References: <5260@uiucdcs.UUCP> Organization: Central Services Org., Piscataway N.J. Lines: 11 Why should checking for -0 be significantly faster then checking the twos compliment tag -2**(word size) - 1 ? This would gain the arithmetic op tag, solve the compliment problem, and be only slightly higher software overhead to emulate larger wordsize fixed point arithmetic The only rational way to do either tag test would be in hardware (as opposed to interpreter horizontal microcode) in parallel, clogging further a big bottleneck, register-ALU pathways, which is probably why few of the ones compliment architectures have -0 propagation traps. {harpo,houxm,ihnp4}!pyuxss!aaw Aaron Werman