X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;ds=sidebyside;f=lib%2Ffrexp.c;h=26bdec9a7162185e1a2d41b4ccd12cccf623e798;hb=531e3287a33c005edeeba10b0ab0910c6686e049;hp=701f00eefb1d3a9adc1a0eeba9bfd2bf6af89a92;hpb=cdaeb6bb213d6042df46e0b3584718ede9f18511;p=gnulib.git diff --git a/lib/frexp.c b/lib/frexp.c index 701f00eef..26bdec9a7 100644 --- a/lib/frexp.c +++ b/lib/frexp.c @@ -1,62 +1,61 @@ /* Split a double into fraction and mantissa. - Copyright (C) 2007 Free Software Foundation, Inc. + Copyright (C) 2007-2011 Free Software Foundation, Inc. - This program is free software; you can redistribute it and/or modify + 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. + the Free Software Foundation; either version 3 of the License, 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. */ + You should have received a copy of the GNU General Public License + along with this program. If not, see . */ /* Written by Paolo Bonzini , 2003, and Bruno Haible , 2007. */ -#include - -#if !(defined USE_LONG_DOUBLE && !HAVE_LONG_DOUBLE) +#if ! defined USE_LONG_DOUBLE +# include +#endif /* Specification. */ -# include +#include -# include -# ifdef USE_LONG_DOUBLE -# include "isnanl-nolibm.h" -# include "fpucw.h" -# else -# include "isnan.h" -# endif +#include +#ifdef USE_LONG_DOUBLE +# include "isnanl-nolibm.h" +# include "fpucw.h" +#else +# include "isnand-nolibm.h" +#endif /* This file assumes FLT_RADIX = 2. If FLT_RADIX is a power of 2 greater than 2, or not even a power of 2, some rounding errors can occur, so that then the returned mantissa is only guaranteed to be <= 1.0, not < 1.0. */ -# ifdef USE_LONG_DOUBLE -# define FUNC frexpl -# define DOUBLE long double -# define ISNAN isnanl -# define DECL_ROUNDING DECL_LONG_DOUBLE_ROUNDING -# define BEGIN_ROUNDING() BEGIN_LONG_DOUBLE_ROUNDING () -# define END_ROUNDING() END_LONG_DOUBLE_ROUNDING () -# define L_(literal) literal##L -# else -# define FUNC frexp -# define DOUBLE double -# define ISNAN isnan -# define DECL_ROUNDING -# define BEGIN_ROUNDING() -# define END_ROUNDING() -# define L_(literal) literal -# endif +#ifdef USE_LONG_DOUBLE +# define FUNC frexpl +# define DOUBLE long double +# define ISNAN isnanl +# define DECL_ROUNDING DECL_LONG_DOUBLE_ROUNDING +# define BEGIN_ROUNDING() BEGIN_LONG_DOUBLE_ROUNDING () +# define END_ROUNDING() END_LONG_DOUBLE_ROUNDING () +# define L_(literal) literal##L +#else +# define FUNC frexp +# define DOUBLE double +# define ISNAN isnand +# define DECL_ROUNDING +# define BEGIN_ROUNDING() +# define END_ROUNDING() +# define L_(literal) literal +#endif DOUBLE -FUNC (DOUBLE x, int *exp) +FUNC (DOUBLE x, int *expptr) { int sign; int exponent; @@ -65,7 +64,7 @@ FUNC (DOUBLE x, int *exp) /* Test for NaN, infinity, and zero. */ if (ISNAN (x) || x + x == x) { - *exp = 0; + *expptr = 0; return x; } @@ -88,73 +87,73 @@ FUNC (DOUBLE x, int *exp) exponent = 0; if (x >= L_(1.0)) { - /* A positive exponent. */ - DOUBLE pow2_i; /* = pow2[i] */ - DOUBLE powh_i; /* = powh[i] */ - - /* Invariants: pow2_i = 2^2^i, powh_i = 2^-2^i, - x * 2^exponent = argument, x >= 1.0. */ - for (i = 0, pow2_i = L_(2.0), powh_i = L_(0.5); - ; - i++, pow2_i = pow2_i * pow2_i, powh_i = powh_i * powh_i) - { - if (x >= pow2_i) - { - exponent += (1 << i); - x *= powh_i; - } - else - break; - - pow2[i] = pow2_i; - powh[i] = powh_i; - } - /* Avoid making x too small, as it could become a denormalized - number and thus lose precision. */ - while (i > 0 && x < pow2[i - 1]) - { - i--; - powh_i = powh[i]; - } - exponent += (1 << i); - x *= powh_i; - /* Here 2^-2^i <= x < 1.0. */ + /* A positive exponent. */ + DOUBLE pow2_i; /* = pow2[i] */ + DOUBLE powh_i; /* = powh[i] */ + + /* Invariants: pow2_i = 2^2^i, powh_i = 2^-2^i, + x * 2^exponent = argument, x >= 1.0. */ + for (i = 0, pow2_i = L_(2.0), powh_i = L_(0.5); + ; + i++, pow2_i = pow2_i * pow2_i, powh_i = powh_i * powh_i) + { + if (x >= pow2_i) + { + exponent += (1 << i); + x *= powh_i; + } + else + break; + + pow2[i] = pow2_i; + powh[i] = powh_i; + } + /* Avoid making x too small, as it could become a denormalized + number and thus lose precision. */ + while (i > 0 && x < pow2[i - 1]) + { + i--; + powh_i = powh[i]; + } + exponent += (1 << i); + x *= powh_i; + /* Here 2^-2^i <= x < 1.0. */ } else { - /* A negative or zero exponent. */ - DOUBLE pow2_i; /* = pow2[i] */ - DOUBLE powh_i; /* = powh[i] */ - - /* Invariants: pow2_i = 2^2^i, powh_i = 2^-2^i, - x * 2^exponent = argument, x < 1.0. */ - for (i = 0, pow2_i = L_(2.0), powh_i = L_(0.5); - ; - i++, pow2_i = pow2_i * pow2_i, powh_i = powh_i * powh_i) - { - if (x < powh_i) - { - exponent -= (1 << i); - x *= pow2_i; - } - else - break; - - pow2[i] = pow2_i; - powh[i] = powh_i; - } - /* Here 2^-2^i <= x < 1.0. */ + /* A negative or zero exponent. */ + DOUBLE pow2_i; /* = pow2[i] */ + DOUBLE powh_i; /* = powh[i] */ + + /* Invariants: pow2_i = 2^2^i, powh_i = 2^-2^i, + x * 2^exponent = argument, x < 1.0. */ + for (i = 0, pow2_i = L_(2.0), powh_i = L_(0.5); + ; + i++, pow2_i = pow2_i * pow2_i, powh_i = powh_i * powh_i) + { + if (x < powh_i) + { + exponent -= (1 << i); + x *= pow2_i; + } + else + break; + + pow2[i] = pow2_i; + powh[i] = powh_i; + } + /* Here 2^-2^i <= x < 1.0. */ } /* Invariants: x * 2^exponent = argument, and 2^-2^i <= x < 1.0. */ while (i > 0) { - i--; - if (x < powh[i]) - { - exponent -= (1 << i); - x *= pow2[i]; - } + i--; + if (x < powh[i]) + { + exponent -= (1 << i); + x *= pow2[i]; + } } /* Here 0.5 <= x < 1.0. */ } @@ -164,14 +163,6 @@ FUNC (DOUBLE x, int *exp) END_ROUNDING (); - *exp = exponent; + *expptr = exponent; return x; } - -#else - -/* This declaration is solely to ensure that after preprocessing - this file is never empty. */ -typedef int dummy; - -#endif