Date: Sat, 23 Jul 2005 04:50:19 GMT From: Roman Bogorodskiy <bogorodskiy@gmail.com> To: freebsd-standards@FreeBSD.org Subject: Re: standards/83845: [ patch ] add log2() and log2f() support for libm Message-ID: <200507230450.j6N4oJnb087348@freefall.freebsd.org>
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The following reply was made to PR standards/83845; it has been noted by GNATS. From: Roman Bogorodskiy <bogorodskiy@gmail.com> To: "Steven G. Kargl" <kargls@comcast.net> Cc: bug-followup@FreeBSD.org Subject: Re: standards/83845: [ patch ] add log2() and log2f() support for libm Date: Sat, 23 Jul 2005 08:50:13 +0400 --qMm9M+Fa2AknHoGS Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Steven wrote: > See standards/82654. >=20 > I have implementations for several C99 long double math functions, > and in the process I implemented log2 and logf. I also wrote or That's really great, since our libmath is a bit outdated and nobody seems to care about that. > edited the man pages. IMHO, for log2[fl], we want to use frexp[fl] > to break x into x =3D f * 2**n where f is in the range [0.5,1). We > then have log2(x) =3D n + log2(f). We can now either evaluate log2(f) > as log(f)/log(2) or directly use a polynomial approximation. That looks reasonable. Actually, I don't care which implementation will be used, your or mine or some another, I'd just like to have it implemented. But looking at the batch of open standarts PRs I think we have no chance to get it committed in the near future. :( Roman Bogorodskiy --qMm9M+Fa2AknHoGS Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.1 (FreeBSD) iQCVAwUBQuHMhYB0WzgdqspGAQKjRgP8Dz5gl/1TVHAhQNGOHEMkOtmFSV3JZmpf 7yUlIQ3Q3Olh6WKVIdvgX1JdV9Fia/VJhea4ESJx85OrgSl8gQsmYZJhO2sSm2Kj 5OINHr68rVsMdY24F6ZiNOTOkeQZySfLX6m0sVsfrY/GIFEBqpQiqbnsTmSqZUx4 WTeishBNtqU= =+Ngs -----END PGP SIGNATURE----- --qMm9M+Fa2AknHoGS--
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