Date: Thu, 27 Apr 2000 09:34:34 +1000 From: "Andrew Reilly" <areilly@nsw.bigpond.net.au> To: Dan Nelson <dnelson@emsphone.com> Cc: Sheldon Hearn <sheldonh@uunet.co.za>, Brooks Davis <brooks@one-eyed-alien.net>, Nate Lawson <nate@elite.net>, freebsd-hackers@FreeBSD.ORG, freebsd-ports@FreeBSD.ORG, davidm@hpl.hp.com Subject: Re: floating point exceptions Message-ID: <20000427093434.A81401@gurney.reilly.home> In-Reply-To: <20000426110345.A13173@dan.emsphone.com> References: <20000425000523.A17224@orion.ac.hmc.edu> <24238.956752200@axl.ops.uunet.co.za> <20000426110345.A13173@dan.emsphone.com>
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On Wed, Apr 26, 2000 at 11:03:45AM -0500, Dan Nelson wrote: > In the last episode (Apr 26), Sheldon Hearn said: > > On Tue, 25 Apr 2000 00:05:23 MST, Brooks Davis wrote: > > > > Is FreeBSD's behavior correct? Why or why not? You can use the > > > > included code snippet to verify that this occurs. > > > > > > FreeBSD has traditionaly violated the IEEE FP standard in this > > > regard. This is fixed in 5.0 and I think in 4.0-STABLE (though I > > > can't remember what file this is in so I can't check.) > > > > Huh? I'm pretty sure you've got this backwards. FreeBSD has > > traditionally upheld the standard and we only recently decided to go > > with the flow in 5.0. > > No; we held our moral ground against IEEE, until 5.0 when we gave in. > The IEEE standard says "trap nothing". For most programs, this is the > wrong thing to do, since they are not signal-processing apps or > numerical analysis programs and a divide by zero is a coding error. > I'd rather have my program die on an unexpected divide by zero than > continue with invalid data. > > Why should we treat (1.0/0.0) any differently from (1/0)? Because 0.0 might be the closest approximation to whatever number you were really trying to divide by that the hardware can manage. 0 is never an approximation to 1 or -1. Dividing is for wimps, anyway. :-) -- Andrew To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-ports" in the body of the message
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