Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84; site tulane.UUCP Path: utzoo!watmath!clyde!bonnie!akgua!akgub!tulane!jfk From: jfk@tulane.UUCP (John Kreuter) Newsgroups: net.arch Subject: Re: uninitialized data Message-ID: <164@tulane.UUCP> Date: Wed, 25-Sep-85 12:17:45 EDT Article-I.D.: tulane.164 Posted: Wed Sep 25 12:17:45 1985 Date-Received: Sat, 28-Sep-85 06:57:58 EDT References: <436@uvm-cs.UUCP> Organization: Tulane University, Dept. of Computer Science Lines: 23 > > Laex Colvin asks about an architecture that traps on using uniniitialized > data. The CDC 6000 series architecture does sort of. An option to the loader > will cause all data locations to be filled with a bit pattern representing > "indefinite" which the CPU will choke on. > -- > Stephen J. Hartley > USENET: {decvax,ihnp4}!dartvax!uvm-gen!uvm-cs!hartley University of Vermont > CSNET: hartley%uvm@csnet-relay (802) 656-3330, 862-5323 This is an extremely high overhead way of checking for uninitialized data. An alternative would be an architecture in which a small tag field identifies the type of the data. This would have the further advantage of allowing, say, arithmetic operators to be overloaded as they are in high level languages. See "Advances in Computer Architecture", by Glenford J. Meyers (John Wiley and sons, 1978) John Kreuter Tulane University New Orleans {decvax, ihnp4}!ulysses!tulane!jfk Brought to you by Super Global Mega Corp .com