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Date:      Fri, 13 Jul 2012 13:07:59 -0400
From:      John Baldwin <jhb@freebsd.org>
To:        David Schultz <das@freebsd.org>
Cc:        Diane Bruce <db@db.net>, David Chisnall <theraven@freebsd.org>, freebsd-current@freebsd.org, Steve Kargl <sgk@troutmask.apl.washington.edu>, Peter Jeremy <peter@rulingia.com>, Warner Losh <imp@bsdimp.com>
Subject:   Re: Use of C99 extra long double math functions after r236148
Message-ID:  <201207131307.59537.jhb@freebsd.org>
In-Reply-To: <20120713155805.GC81965@zim.MIT.EDU>
References:  <20120529045612.GB4445@server.rulingia.com> <C527B388-3537-406F-BA6D-2FA45B9EAA3B@FreeBSD.org> <20120713155805.GC81965@zim.MIT.EDU>

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On Friday, July 13, 2012 11:58:05 am David Schultz wrote:
> On Fri, Jul 13, 2012, David Chisnall wrote:
> > As do I.  I'd also point out that the ONLY requirement for long
> > double according to the standard is that it has at least the same
> > precision as double.  Therefore, any implementation of these
> > functions that is no worse that the double version is compliant.
> > Once we have something meeting a minimum standard, then I'm very
> > happy to see it improved, but having C99 functions missing now is
> > just embarrassing while we're working on adding C11 features.
> 
> There are several things wrong with this reasoning, but pragmatically
> the conclusion may be right: we do have a long list of users who would
> prefer a dubious implementation to none at all.
> 
> I propose we set a timeframe for this, on the order of a few months.
> A rough outline might be something like:
> 
>   mid-August: expl logl log2l log10l
>      -- just need to clean up Bruce and Steve's work; Steve recently
>         sent me patches for expl, which I hope get committed soon
>   mid-September: acoshl asinhl atanhl coshl sinhl tanhl
>      -- easy once expl is in; others could probably help
>   mid-October: powl expm1l
>   mid-November: most complex.h functions
> 
> If the schedule can't be met, then we can just import Cephes as an
> interim solution without further ado.  This provides Bruce and Steve
> an opportunity to commit what they have been working on, without
> forcing the rest of the FreeBSD community to wait indefinitely for
> the pie in the sky.
> 
> By the way, the trig and complex functions are areas where anyone with
> some calculus background could contribute.  If anyone is interested in
> helping out, I'd be happy to coordinate things and review patches,
> although I will be unavailable for much of August.

I think this sounds like an excellent plan, thanks!

-- 
John Baldwin



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