diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/ceil.c | 83 | ||||
| -rw-r--r-- | lib/ceilf.c | 21 | ||||
| -rw-r--r-- | lib/math.in.h | 13 |
3 files changed, 117 insertions, 0 deletions
diff --git a/lib/ceil.c b/lib/ceil.c new file mode 100644 index 0000000000..ced224ca82 --- /dev/null +++ b/lib/ceil.c @@ -0,0 +1,83 @@ +/* Round towards positive infinity. + Copyright (C) 2007 Free Software Foundation, Inc. + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 2, or (at your option) + any later version. + + This program 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 General Public License for more details. + + You should have received a copy of the GNU General Public License along + with this program; if not, write to the Free Software Foundation, + Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ + +/* Written by Bruno Haible <bruno@clisp.org>, 2007. */ + +#include <config.h> + +/* Specification. */ +#include <math.h> + +#include <float.h> + +#ifdef USE_LONG_DOUBLE +# define FUNC ceill +# define DOUBLE long double +# define MANT_DIG LDBL_MANT_DIG +# define L_(literal) literal##L +#elif ! defined USE_FLOAT +# define FUNC ceil +# define DOUBLE double +# define MANT_DIG DBL_MANT_DIG +# define L_(literal) literal +#else /* defined USE_FLOAT */ +# define FUNC ceilf +# define DOUBLE float +# define MANT_DIG FLT_MANT_DIG +# define L_(literal) literal##f +#endif + +/* 2^(MANT_DIG-1). */ +static const double TWO_MANT_DIG = + /* Assume MANT_DIG <= 5 * 31. + Use the identity + n = floor(n/5) + floor((n+1)/5) + ... + floor((n+4)/5). */ + (DOUBLE) (1U << ((MANT_DIG - 1) / 5)) + * (DOUBLE) (1U << ((MANT_DIG - 1 + 1) / 5)) + * (DOUBLE) (1U << ((MANT_DIG - 1 + 2) / 5)) + * (DOUBLE) (1U << ((MANT_DIG - 1 + 3) / 5)) + * (DOUBLE) (1U << ((MANT_DIG - 1 + 4) / 5)); + +DOUBLE +FUNC (DOUBLE x) +{ + /* The use of 'volatile' guarantees that excess precision bits are dropped + at each addition step and before the following comparison at the caller's + site. It is necessary on x86 systems where double-floats are not IEEE + compliant by default, to avoid that the results become platform and compiler + option dependent. 'volatile' is a portable alternative to gcc's + -ffloat-store option. */ + volatile DOUBLE y = x; + volatile DOUBLE z = y; + + /* Round to the next integer (nearest or up or down, doesn't matter). */ + if (z > L_(0.0)) + { + z += TWO_MANT_DIG; + z -= TWO_MANT_DIG; + } + else if (z < L_(0.0)) + { + z -= TWO_MANT_DIG; + z += TWO_MANT_DIG; + } + /* Enforce rounding up. */ + if (z < y) + z += L_(1.0); + + return z; +} diff --git a/lib/ceilf.c b/lib/ceilf.c new file mode 100644 index 0000000000..8f6db345a7 --- /dev/null +++ b/lib/ceilf.c @@ -0,0 +1,21 @@ +/* Round towards positive infinity. + Copyright (C) 2007 Free Software Foundation, Inc. + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 2, or (at your option) + any later version. + + This program 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 General Public License for more details. + + You should have received a copy of the GNU General Public License along + with this program; if not, write to the Free Software Foundation, + Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ + +/* Written by Bruno Haible <bruno@clisp.org>, 2007. */ + +#define USE_FLOAT +#include "ceil.c" diff --git a/lib/math.in.h b/lib/math.in.h index 490524276d..ef0682af58 100644 --- a/lib/math.in.h +++ b/lib/math.in.h @@ -90,6 +90,19 @@ extern long double atanl (long double x); #endif +#if @GNULIB_CEILF@ +# if !@HAVE_DECL_CEILF@ +# define ceilf rpl_ceilf +extern float ceilf (float x); +# endif +#elif defined GNULIB_POSIXCHECK +# undef ceilf +# define ceilf(x) \ + (GL_LINK_WARNING ("ceilf is unportable - " \ + "use gnulib module ceilf for portability"), \ + ceilf (x)) +#endif + #if @GNULIB_MATHL@ || !@HAVE_DECL_CEILL@ extern long double ceill (long double x); #endif |