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Diffstat (limited to 'lib/round.c')
| -rw-r--r-- | lib/round.c | 168 |
1 files changed, 0 insertions, 168 deletions
diff --git a/lib/round.c b/lib/round.c deleted file mode 100644 index 1630a6d79..000000000 --- a/lib/round.c +++ /dev/null @@ -1,168 +0,0 @@ -/* Round toward nearest, breaking ties away from zero. - Copyright (C) 2007, 2010-2011 Free Software Foundation, Inc. - - This program 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, 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 Lesser General Public License for more details. - - You should have received a copy of the GNU Lesser 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 Ben Pfaff <blp@gnu.org>, 2007. - Based heavily on code by Bruno Haible. */ - -#include <config.h> - -/* Specification. */ -#include <math.h> - -#include <float.h> - -#undef MIN - -#ifdef USE_LONG_DOUBLE -# define ROUND roundl -# define FLOOR floorl -# define CEIL ceill -# define DOUBLE long double -# define MANT_DIG LDBL_MANT_DIG -# define MIN LDBL_MIN -# define L_(literal) literal##L -# define HAVE_FLOOR_AND_CEIL HAVE_FLOORL_AND_CEILL -#elif ! defined USE_FLOAT -# define ROUND round -# define FLOOR floor -# define CEIL ceil -# define DOUBLE double -# define MANT_DIG DBL_MANT_DIG -# define MIN DBL_MIN -# define L_(literal) literal -# define HAVE_FLOOR_AND_CEIL 1 -#else /* defined USE_FLOAT */ -# define ROUND roundf -# define FLOOR floorf -# define CEIL ceilf -# define DOUBLE float -# define MANT_DIG FLT_MANT_DIG -# define MIN FLT_MIN -# define L_(literal) literal##f -# define HAVE_FLOOR_AND_CEIL HAVE_FLOORF_AND_CEILF -#endif - -/* -0.0. See minus-zero.h. */ -#if defined __hpux || defined __sgi || defined __ICC -# define MINUS_ZERO (-MIN * MIN) -#else -# define MINUS_ZERO L_(-0.0) -#endif - -/* If we're being included from test-round2[f].c, it already defined names for - our round implementations. Otherwise, pick the preferred implementation for - this machine. */ -#if !defined FLOOR_BASED_ROUND && !defined FLOOR_FREE_ROUND -# if HAVE_FLOOR_AND_CEIL -# define FLOOR_BASED_ROUND ROUND -# else -# define FLOOR_FREE_ROUND ROUND -# endif -#endif - -#ifdef FLOOR_BASED_ROUND -/* An implementation of the C99 round function based on floor and ceil. We use - this when floor and ceil are available, on the assumption that they are - faster than the open-coded versions below. */ -DOUBLE -FLOOR_BASED_ROUND (DOUBLE x) -{ - if (x >= L_(0.0)) - { - DOUBLE y = FLOOR (x); - if (x - y >= L_(0.5)) - y += L_(1.0); - return y; - } - else - { - DOUBLE y = CEIL (x); - if (y - x >= L_(0.5)) - y -= L_(1.0); - return y; - } -} -#endif /* FLOOR_BASED_ROUND */ - -#ifdef FLOOR_FREE_ROUND -/* An implementation of the C99 round function without floor or ceil. - We use this when floor or ceil is missing. */ -DOUBLE -FLOOR_FREE_ROUND (DOUBLE x) -{ - /* 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)); - - /* 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; - - if (z > L_(0.0)) - { - /* Avoid rounding error for x = 0.5 - 2^(-MANT_DIG-1). */ - if (z < L_(0.5)) - z = L_(0.0); - /* Avoid rounding errors for values near 2^k, where k >= MANT_DIG-1. */ - else if (z < TWO_MANT_DIG) - { - /* Add 0.5 to the absolute value. */ - y = z += L_(0.5); - /* Round to the next integer (nearest or up or down, doesn't - matter). */ - z += TWO_MANT_DIG; - z -= TWO_MANT_DIG; - /* Enforce rounding down. */ - if (z > y) - z -= L_(1.0); - } - } - else if (z < L_(0.0)) - { - /* Avoid rounding error for x = -(0.5 - 2^(-MANT_DIG-1)). */ - if (z > - L_(0.5)) - z = MINUS_ZERO; - /* Avoid rounding errors for values near -2^k, where k >= MANT_DIG-1. */ - else if (z > -TWO_MANT_DIG) - { - /* Add 0.5 to the absolute value. */ - y = z -= L_(0.5); - /* Round to the next integer (nearest or up or down, doesn't - matter). */ - z -= TWO_MANT_DIG; - z += TWO_MANT_DIG; - /* Enforce rounding up. */ - if (z < y) - z += L_(1.0); - } - } - return z; -} -#endif /* FLOOR_FREE_ROUND */ - |