Date: Sun, 9 Dec 2007 17:39:18 -0500 From: David Schultz <das@FreeBSD.ORG> To: Steve Kargl <sgk@troutmask.apl.washington.edu> Cc: freebsd-standards@FreeBSD.ORG Subject: Re: Implementation of expl() Message-ID: <20071209223918.GA9920@VARK.MIT.EDU> In-Reply-To: <20071209213450.GA95726@troutmask.apl.washington.edu> References: <20071103001305.GA82775@troutmask.apl.washington.edu> <20071209212505.GA9698@VARK.MIT.EDU> <20071209213450.GA95726@troutmask.apl.washington.edu>
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On Sun, Dec 09, 2007, Steve Kargl wrote: > On Sun, Dec 09, 2007 at 04:25:05PM -0500, David Schultz wrote: > > On Fri, Nov 02, 2007, Steve Kargl wrote: > > > With all the success of developing several other missing > > > C99 math routines, I decided to tackle expl() (which I > > > need to tackle tanhl()). > > > > Hmm, great, but where's the patch? :) Maybe the mailing list > > software ate it. > > This is the current version. I need to revise how I computed > the ploynomial coefficient. In short, I mapped r in > [-ln(2)/2:ln(2)/2] into the range x in [-1,1] for the Chebyshev > interpolation, but I never scaled x back into r. This is the > reason why the lines "r = r * TOLN2;" exists. Some minor fixes (mostly whitespace) are below. Also, don't you lose precision when you do stuff like this? z.e = 1 / z.e; In any case, if you can get me the appropriate constants for the 128-bit format, I'll clean everything up and check it in, which will make a lot of ports maintainers happy. That will pave the way to other stuff (e.g., MD versions of this) as well. We can worry about subnormals later.
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