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author | vlefevre <vlefevre@280ebfd0-de03-0410-8827-d642c229c3f4> | 2002-03-04 23:35:05 +0000 |
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committer | vlefevre <vlefevre@280ebfd0-de03-0410-8827-d642c229c3f4> | 2002-03-04 23:35:05 +0000 |
commit | d6f05d264f033c608dadd142cd9ed74ffc962787 (patch) | |
tree | 1cfda4b66ad2acf5a0d1fee238c5819caa071c65 /uceil_log2.c | |
parent | c6aad16d1e41f5c4244a6eb1c51ff952c4607214 (diff) | |
download | mpfr-d6f05d264f033c608dadd142cd9ed74ffc962787.tar.gz |
File renaming.
git-svn-id: svn://scm.gforge.inria.fr/svn/mpfr/trunk@1714 280ebfd0-de03-0410-8827-d642c229c3f4
Diffstat (limited to 'uceil_log2.c')
-rw-r--r-- | uceil_log2.c | 40 |
1 files changed, 40 insertions, 0 deletions
diff --git a/uceil_log2.c b/uceil_log2.c new file mode 100644 index 000000000..9decc009f --- /dev/null +++ b/uceil_log2.c @@ -0,0 +1,40 @@ +/* _mpfr_ceil_log2 - returns ceil(log(d)/log(2)) + +Copyright 1999, 2000, 2001, 2002 Free Software Foundation. + +This file is part of the MPFR Library. + +The MPFR Library is free software; you can redistribute it and/or modify +it under the terms of the GNU Lesser General Public License as published by +the Free Software Foundation; either version 2.1 of the License, or (at your +option) any later version. + +The MPFR Library is distributed in the hope that it will be useful, but +WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY +or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public +License for more details. + +You should have received a copy of the GNU Lesser General Public License +along with the MPFR Library; see the file COPYING.LIB. If not, write to +the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, +MA 02111-1307, USA. */ + +#include "gmp.h" +#include "gmp-impl.h" +#include "mpfr.h" +#include "mpfr-impl.h" + +/* returns ceil(log(d)/log(2)) */ +long +_mpfr_ceil_log2 (double d) +{ + long exp; + union ieee_double_extract x; + + x.d = d; + exp = x.s.exp - 1023; + x.s.exp = 1023; /* value for 1 <= d < 2 */ + if (x.d != 1.0) /* d: not a power of two? */ + exp++; + return exp; +} |