From: utzoo!henry Newsgroups: net.micro.68k Title: Re: 68K vs 286 on floats Article-I.D.: utzoo.2839 Posted: Mon Feb 28 17:01:27 1983 Received: Mon Feb 28 17:01:27 1983 No offense to John Gilmore and the other folks at Sun, but comparing Sun's 32-bit software floating point to the IEEE-standard 8087/80287 is really comparing a Piper Cub to a Concorde. What are the error bounds of the Sun package? What is its roundoff algorithm, and why? Under what circumstances is it unsafe to use? (Alas, considering my past experience with software floating-point packages, a better question would probably be "under what circumstances is it safe to use?".) I don't doubt that the folks who did it were competent -- certainly the Sun people that I know are pretty good -- but designing floating-point arithmetic algorithms is a job for a numerical-mathematics expert, not a systems programmer. It really is too big and too hard a job for an amateur to do well. If somebody like (say) Kahan was numerical-mathematics consultant to the project, and is satisfied with the result, then I'd be happy to use it. Otherwise, I wouldn't trust the numbers coming out. Sorry. Actually, what I would like to see is a decent 68000 or 16032 system (the Sun is reasonable) with an 80[2]87 on it for floating-point work. The promised 68000 and 16032 floating-point auxiliaries are useful things, but they don't have quite the same awe-inspiring capabilities and specs as the Intel chips. A lot of people have cursed the 8087 for being impossible to interface to anything but an 8086; by the sounds of things, the 80287 may be easier to deal with. Henry Spencer U of Toronto