Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.1 6/24/83; site wu1.UUCP Path: utzoo!watmath!clyde!burl!ulysses!allegra!mit-eddie!godot!harvard!seismo!cmcl2!rna!rocky2!cubsvax!wu1!rf From: rf@wu1.UUCP Newsgroups: net.micro.68k,net.micro Subject: Re: MC68881 Floating-point performance times (timing of single and double precision computation) Message-ID: <327@wu1.UUCP> Date: Wed, 12-Dec-84 13:13:43 EST Article-I.D.: wu1.327 Posted: Wed Dec 12 13:13:43 1984 Date-Received: Sat, 15-Dec-84 01:49:56 EST References: <263@oakhill.UUCP>, <896@utastro.UUCP> Organization: Western Union Telegraph, Mahwah, NJ Lines: 14 Xref: watmath net.micro.68k:492 net.micro:8903 Ed Nather ({allegra,ihnp4}!{ut-sally,noao}!utastro!nather) writes: Perhaps the most interesting thing about these timings is that there is essentially NO PENALTY IN USING DOUBLE vs SINGLE PRECISION in the basic floating point operations. Say WHAT? The timing chart shows single precision multiply as about 1/4 faster than double precision multiply. Single precision divide is similarly faster than double precision divide. There is also a penalty for fetching double-precision constants from memory. "Orion shall rise!" Randolph Fritz UUCPnet: {ihnp4,decvax}!philabs!wu1!rf