Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!watmath!clyde!burl!ulysses!mhuxl!ihnp4!inuxc!pur-ee!uiucdcs!parsec!ctvax!uokvax!andree From: andree@uokvax.UUCP Newsgroups: net.arch Subject: Re: Re: Complement Arithmetic - (nf) Message-ID: <5448@uiucdcs.UUCP> Date: Tue, 7-Feb-84 23:42:55 EST Article-I.D.: uiucdcs.5448 Posted: Tue Feb 7 23:42:55 1984 Date-Received: Fri, 10-Feb-84 01:42:35 EST Lines: 23 #R:burdvax:-142500:uokvax:9900007:000:865 uokvax!andree Feb 5 04:15:00 1984 /***** uokvax:net.arch / kobold!tjt / 5:43 pm Feb 3, 1984 */ Mike Andree (..!uokvax!andree) has suggested using "-0" on a one's-complement machine to represent an illegal value for uninitialized variables. He was hoping that this would result in no extra (software) cost. Unfortunately, TANSTAAFL: somebody has to initialize those uninitialized variables with the illegal value. -- Tom Teixeira, Massachusetts Computer Corporation. Westford MA ...!{ihnp4,harpo,decvax}!masscomp!tjt (617) 692-6200 x275 /* ---------- */ Somebody, somewhere had to initalize them anyway :-). I was actually refering to runtime costs - you don't have to generate code to test for the illegal value before each statement. At least one compiler (the Waterloo Fortran V) does this now. It's a good idea, but the cost! [If you're interested, the value is 2 * ' '.]