gnulib: lib/round.c annotate

annotate lib/round.c @ 17363:5a51fb7777a9

sys_select, sys_time: port 2013-01-30 Solaris 2.6 fix to Cygwin Problem reported by Marco Atzeri in <http://lists.gnu.org/archive/html/bug-gnulib/2013-03/msg00000.html>. * lib/sys_select.in.h [HAVE_SYS_SELECT_H && _CYGWIN_SYS_TIME_H]: Simply delegate to the system <sys/select.h> in this case too. Also, pay attention to _GL_SYS_SELECT_H_REDIRECT_FROM_SYS_TIME_H only if OSF/1, since otherwise Cygwin breaks, and it doesn't seem to be needed on Solaris either. * lib/sys_time.in.h [_CYGWIN_SYS_TIME_H]: Simply delgate to the system <sys/time.h> in this case.

author	Paul Eggert <eggert@cs.ucla.edu>
date	Tue, 19 Mar 2013 09:08:47 -0700
parents	e542fd46ad6f
children	344018b6e5d7

rev	line source
9375 96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	1 /* Round toward nearest, breaking ties away from zero.
17249 e542fd46ad6f maint: update all copyright year number ranges Eric Blake <eblake@redhat.com> parents: 16506 diff changeset	2 Copyright (C) 2007, 2010-2013 Free Software Foundation, Inc.
9375 96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	3
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	4 This program is free software; you can redistribute it and/or modify
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	5 it under the terms of the GNU General Public License as published by
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	6 the Free Software Foundation; either version 2, or (at your option)
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	7 any later version.
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	8
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	9 This program is distributed in the hope that it will be useful,
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	10 but WITHOUT ANY WARRANTY; without even the implied warranty of
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	12 GNU General Public License for more details.
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	13
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	14 You should have received a copy of the GNU General Public License along
16366 bb182ee4a09d maint: replace FSF snail-mail addresses with URLs Paul Eggert <eggert@cs.ucla.edu> parents: 16297 diff changeset	15 with this program; if not, see <http://www.gnu.org/licenses/>. */
9375 96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	16
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	17 /* Written by Ben Pfaff <blp@gnu.org>, 2007.
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	18 Based heavily on code by Bruno Haible. */
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	19
15927 afd47902c4b4 roundl: Simplify for platforms where 'long double' == 'double'. Bruno Haible <bruno@clisp.org> parents: 14079 diff changeset	20 #if ! defined USE_LONG_DOUBLE
afd47902c4b4 roundl: Simplify for platforms where 'long double' == 'double'. Bruno Haible <bruno@clisp.org> parents: 14079 diff changeset	21 # include <config.h>
afd47902c4b4 roundl: Simplify for platforms where 'long double' == 'double'. Bruno Haible <bruno@clisp.org> parents: 14079 diff changeset	22 #endif
9375 96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	23
14018 ac9f59901721 ceil, trunc, round: Fix gcc warnings. Bruno Haible <bruno@clisp.org> parents: 13994 diff changeset	24 /* Specification. */
ac9f59901721 ceil, trunc, round: Fix gcc warnings. Bruno Haible <bruno@clisp.org> parents: 13994 diff changeset	25 #include <math.h>
ac9f59901721 ceil, trunc, round: Fix gcc warnings. Bruno Haible <bruno@clisp.org> parents: 13994 diff changeset	26
9375 96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	27 #include <float.h>
14018 ac9f59901721 ceil, trunc, round: Fix gcc warnings. Bruno Haible <bruno@clisp.org> parents: 13994 diff changeset	28
ac9f59901721 ceil, trunc, round: Fix gcc warnings. Bruno Haible <bruno@clisp.org> parents: 13994 diff changeset	29 #undef MIN
9375 96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	30
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	31 #ifdef USE_LONG_DOUBLE
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	32 # define ROUND roundl
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	33 # define FLOOR floorl
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	34 # define CEIL ceill
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	35 # define DOUBLE long double
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	36 # define MANT_DIG LDBL_MANT_DIG
13994 b91bc81df379 round: Implement result sign according to IEEE 754. Bruno Haible <bruno@clisp.org> parents: 12559 diff changeset	37 # define MIN LDBL_MIN
9375 96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	38 # define L_(literal) literal##L
9466 1013cba29012 Handle the case that floorl and roundl are declared but do not exist. Bruno Haible <bruno@clisp.org> parents: 9375 diff changeset	39 # define HAVE_FLOOR_AND_CEIL HAVE_FLOORL_AND_CEILL
9375 96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	40 #elif ! defined USE_FLOAT
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	41 # define ROUND round
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	42 # define FLOOR floor
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	43 # define CEIL ceil
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	44 # define DOUBLE double
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	45 # define MANT_DIG DBL_MANT_DIG
13994 b91bc81df379 round: Implement result sign according to IEEE 754. Bruno Haible <bruno@clisp.org> parents: 12559 diff changeset	46 # define MIN DBL_MIN
9375 96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	47 # define L_(literal) literal
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	48 # define HAVE_FLOOR_AND_CEIL 1
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	49 #else /* defined USE_FLOAT */
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	50 # define ROUND roundf
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	51 # define FLOOR floorf
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	52 # define CEIL ceilf
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	53 # define DOUBLE float
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	54 # define MANT_DIG FLT_MANT_DIG
13994 b91bc81df379 round: Implement result sign according to IEEE 754. Bruno Haible <bruno@clisp.org> parents: 12559 diff changeset	55 # define MIN FLT_MIN
9375 96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	56 # define L_(literal) literal##f
9466 1013cba29012 Handle the case that floorl and roundl are declared but do not exist. Bruno Haible <bruno@clisp.org> parents: 9375 diff changeset	57 # define HAVE_FLOOR_AND_CEIL HAVE_FLOORF_AND_CEILF
9375 96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	58 #endif
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	59
13994 b91bc81df379 round: Implement result sign according to IEEE 754. Bruno Haible <bruno@clisp.org> parents: 12559 diff changeset	60 /* -0.0. See minus-zero.h. */
b91bc81df379 round: Implement result sign according to IEEE 754. Bruno Haible <bruno@clisp.org> parents: 12559 diff changeset	61 #if defined __hpux \|\| defined __sgi \|\| defined __ICC
b91bc81df379 round: Implement result sign according to IEEE 754. Bruno Haible <bruno@clisp.org> parents: 12559 diff changeset	62 # define MINUS_ZERO (-MIN * MIN)
b91bc81df379 round: Implement result sign according to IEEE 754. Bruno Haible <bruno@clisp.org> parents: 12559 diff changeset	63 #else
b91bc81df379 round: Implement result sign according to IEEE 754. Bruno Haible <bruno@clisp.org> parents: 12559 diff changeset	64 # define MINUS_ZERO L_(-0.0)
b91bc81df379 round: Implement result sign according to IEEE 754. Bruno Haible <bruno@clisp.org> parents: 12559 diff changeset	65 #endif
b91bc81df379 round: Implement result sign according to IEEE 754. Bruno Haible <bruno@clisp.org> parents: 12559 diff changeset	66
16506 fa4e9b981eb4 Avoid compilation errors with MSVC option -fp:strict. Bruno Haible <bruno@clisp.org> parents: 16366 diff changeset	67 /* MSVC with option -fp:strict refuses to compile constant initializers that
fa4e9b981eb4 Avoid compilation errors with MSVC option -fp:strict. Bruno Haible <bruno@clisp.org> parents: 16366 diff changeset	68 contain floating-point operations. Pacify this compiler. */
fa4e9b981eb4 Avoid compilation errors with MSVC option -fp:strict. Bruno Haible <bruno@clisp.org> parents: 16366 diff changeset	69 #ifdef _MSC_VER
fa4e9b981eb4 Avoid compilation errors with MSVC option -fp:strict. Bruno Haible <bruno@clisp.org> parents: 16366 diff changeset	70 # pragma fenv_access (off)
fa4e9b981eb4 Avoid compilation errors with MSVC option -fp:strict. Bruno Haible <bruno@clisp.org> parents: 16366 diff changeset	71 #endif
fa4e9b981eb4 Avoid compilation errors with MSVC option -fp:strict. Bruno Haible <bruno@clisp.org> parents: 16366 diff changeset	72
9375 96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	73 /* If we're being included from test-round2[f].c, it already defined names for
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	74 our round implementations. Otherwise, pick the preferred implementation for
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	75 this machine. */
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	76 #if !defined FLOOR_BASED_ROUND && !defined FLOOR_FREE_ROUND
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	77 # if HAVE_FLOOR_AND_CEIL
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	78 # define FLOOR_BASED_ROUND ROUND
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	79 # else
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	80 # define FLOOR_FREE_ROUND ROUND
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	81 # endif
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	82 #endif
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	83
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	84 #ifdef FLOOR_BASED_ROUND
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	85 /* An implementation of the C99 round function based on floor and ceil. We use
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	86 this when floor and ceil are available, on the assumption that they are
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	87 faster than the open-coded versions below. */
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	88 DOUBLE
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	89 FLOOR_BASED_ROUND (DOUBLE x)
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	90 {
10092 ae7bf97ee30c Remove trailing spaces. Bruno Haible <bruno@clisp.org> parents: 9466 diff changeset	91 if (x >= L_(0.0))
9375 96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	92 {
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	93 DOUBLE y = FLOOR (x);
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	94 if (x - y >= L_(0.5))
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	95 y += L_(1.0);
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	96 return y;
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	97 }
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	98 else
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	99 {
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	100 DOUBLE y = CEIL (x);
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	101 if (y - x >= L_(0.5))
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	102 y -= L_(1.0);
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	103 return y;
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	104 }
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	105 }
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	106 #endif /* FLOOR_BASED_ROUND */
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	107
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	108 #ifdef FLOOR_FREE_ROUND
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	109 /* An implementation of the C99 round function without floor or ceil.
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	110 We use this when floor or ceil is missing. */
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	111 DOUBLE
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	112 FLOOR_FREE_ROUND (DOUBLE x)
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	113 {
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	114 /* 2^(MANT_DIG-1). */
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	115 static const DOUBLE TWO_MANT_DIG =
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	116 /* Assume MANT_DIG <= 5 * 31.
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	117 Use the identity
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	118 n = floor(n/5) + floor((n+1)/5) + ... + floor((n+4)/5). */
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	119 (DOUBLE) (1U << ((MANT_DIG - 1) / 5))
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	120 * (DOUBLE) (1U << ((MANT_DIG - 1 + 1) / 5))
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	121 * (DOUBLE) (1U << ((MANT_DIG - 1 + 2) / 5))
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	122 * (DOUBLE) (1U << ((MANT_DIG - 1 + 3) / 5))
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	123 * (DOUBLE) (1U << ((MANT_DIG - 1 + 4) / 5));
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	124
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	125 /* The use of 'volatile' guarantees that excess precision bits are dropped at
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	126 each addition step and before the following comparison at the caller's
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	127 site. It is necessary on x86 systems where double-floats are not IEEE
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	128 compliant by default, to avoid that the results become platform and
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	129 compiler option dependent. 'volatile' is a portable alternative to gcc's
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	130 -ffloat-store option. */
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	131 volatile DOUBLE y = x;
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	132 volatile DOUBLE z = y;
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	133
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	134 if (z > L_(0.0))
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	135 {
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	136 /* Avoid rounding error for x = 0.5 - 2^(-MANT_DIG-1). */
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	137 if (z < L_(0.5))
12421 e8d2c6fc33ad Use spaces for indentation, not tabs. Bruno Haible <bruno@clisp.org> parents: 10092 diff changeset	138 z = L_(0.0);
9375 96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	139 /* Avoid rounding errors for values near 2^k, where k >= MANT_DIG-1. */
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	140 else if (z < TWO_MANT_DIG)
12421 e8d2c6fc33ad Use spaces for indentation, not tabs. Bruno Haible <bruno@clisp.org> parents: 10092 diff changeset	141 {
e8d2c6fc33ad Use spaces for indentation, not tabs. Bruno Haible <bruno@clisp.org> parents: 10092 diff changeset	142 /* Add 0.5 to the absolute value. */
e8d2c6fc33ad Use spaces for indentation, not tabs. Bruno Haible <bruno@clisp.org> parents: 10092 diff changeset	143 y = z += L_(0.5);
e8d2c6fc33ad Use spaces for indentation, not tabs. Bruno Haible <bruno@clisp.org> parents: 10092 diff changeset	144 /* Round to the next integer (nearest or up or down, doesn't
9375 96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	145 matter). */
12421 e8d2c6fc33ad Use spaces for indentation, not tabs. Bruno Haible <bruno@clisp.org> parents: 10092 diff changeset	146 z += TWO_MANT_DIG;
e8d2c6fc33ad Use spaces for indentation, not tabs. Bruno Haible <bruno@clisp.org> parents: 10092 diff changeset	147 z -= TWO_MANT_DIG;
e8d2c6fc33ad Use spaces for indentation, not tabs. Bruno Haible <bruno@clisp.org> parents: 10092 diff changeset	148 /* Enforce rounding down. */
e8d2c6fc33ad Use spaces for indentation, not tabs. Bruno Haible <bruno@clisp.org> parents: 10092 diff changeset	149 if (z > y)
e8d2c6fc33ad Use spaces for indentation, not tabs. Bruno Haible <bruno@clisp.org> parents: 10092 diff changeset	150 z -= L_(1.0);
e8d2c6fc33ad Use spaces for indentation, not tabs. Bruno Haible <bruno@clisp.org> parents: 10092 diff changeset	151 }
9375 96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	152 }
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	153 else if (z < L_(0.0))
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	154 {
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	155 /* Avoid rounding error for x = -(0.5 - 2^(-MANT_DIG-1)). */
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	156 if (z > - L_(0.5))
13994 b91bc81df379 round: Implement result sign according to IEEE 754. Bruno Haible <bruno@clisp.org> parents: 12559 diff changeset	157 z = MINUS_ZERO;
9375 96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	158 /* Avoid rounding errors for values near -2^k, where k >= MANT_DIG-1. */
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	159 else if (z > -TWO_MANT_DIG)
12421 e8d2c6fc33ad Use spaces for indentation, not tabs. Bruno Haible <bruno@clisp.org> parents: 10092 diff changeset	160 {
e8d2c6fc33ad Use spaces for indentation, not tabs. Bruno Haible <bruno@clisp.org> parents: 10092 diff changeset	161 /* Add 0.5 to the absolute value. */
e8d2c6fc33ad Use spaces for indentation, not tabs. Bruno Haible <bruno@clisp.org> parents: 10092 diff changeset	162 y = z -= L_(0.5);
e8d2c6fc33ad Use spaces for indentation, not tabs. Bruno Haible <bruno@clisp.org> parents: 10092 diff changeset	163 /* Round to the next integer (nearest or up or down, doesn't
9375 96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	164 matter). */
12421 e8d2c6fc33ad Use spaces for indentation, not tabs. Bruno Haible <bruno@clisp.org> parents: 10092 diff changeset	165 z -= TWO_MANT_DIG;
e8d2c6fc33ad Use spaces for indentation, not tabs. Bruno Haible <bruno@clisp.org> parents: 10092 diff changeset	166 z += TWO_MANT_DIG;
e8d2c6fc33ad Use spaces for indentation, not tabs. Bruno Haible <bruno@clisp.org> parents: 10092 diff changeset	167 /* Enforce rounding up. */
e8d2c6fc33ad Use spaces for indentation, not tabs. Bruno Haible <bruno@clisp.org> parents: 10092 diff changeset	168 if (z < y)
e8d2c6fc33ad Use spaces for indentation, not tabs. Bruno Haible <bruno@clisp.org> parents: 10092 diff changeset	169 z += L_(1.0);
e8d2c6fc33ad Use spaces for indentation, not tabs. Bruno Haible <bruno@clisp.org> parents: 10092 diff changeset	170 }
9375 96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	171 }
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	172 return z;
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	173 }
96fea5b2eb11 Implement 'round', 'roundf', 'roundl' modules. Ben Pfaff <blp@cs.stanford.edu> parents: diff changeset	174 #endif /* FLOOR_FREE_ROUND */

Mercurial > gnulib

annotate lib/round.c @ 17363:5a51fb7777a9