octave-lojdl/gnulib-hg: lib/trunc.c annotate

annotate lib/trunc.c @ 15926:23d150bba2eb

truncl: Simplify for platforms where 'long double' == 'double'. * lib/truncl.c: Include <config.h>. (truncl) [HAVE_SAME_LONG_DOUBLE_AS_DOUBLE]: New function. * lib/trunc.c [!USE_LONG_DOUBLE]: Don't include <config.h> a second time. * m4/truncl.m4 (gl_FUNC_TRUNCL): Require gl_LONG_DOUBLE_VS_DOUBLE. Determine TRUNCL_LIBM according to HAVE_SAME_LONG_DOUBLE_AS_DOUBLE. * modules/truncl (Depends-on): Add trunc. Update conditions.

author	Bruno Haible <bruno@clisp.org>
date	Mon, 10 Oct 2011 01:05:53 +0200
parents	97fc9a21a8fb
children	8250f2777afc

rev	line source
9282 9a26e94f946a New module 'trunc'. Bruno Haible <bruno@clisp.org> parents: diff changeset	1 /* Round towards zero.
14079 97fc9a21a8fb maint: update almost all copyright ranges to include 2011 Jim Meyering <meyering@redhat.com> parents: 14018 diff changeset	2 Copyright (C) 2007, 2010-2011 Free Software Foundation, Inc.
9282 9a26e94f946a New module 'trunc'. Bruno Haible <bruno@clisp.org> parents: diff changeset	3
9309 bbbbbf4cd1c5 Change copyright notice from GPLv2+ to GPLv3+. Bruno Haible <bruno@clisp.org> parents: 9285 diff changeset	4 This program is free software: you can redistribute it and/or modify
9282 9a26e94f946a New module 'trunc'. Bruno Haible <bruno@clisp.org> parents: diff changeset	5 it under the terms of the GNU General Public License as published by
9309 bbbbbf4cd1c5 Change copyright notice from GPLv2+ to GPLv3+. Bruno Haible <bruno@clisp.org> parents: 9285 diff changeset	6 the Free Software Foundation; either version 3 of the License, or
bbbbbf4cd1c5 Change copyright notice from GPLv2+ to GPLv3+. Bruno Haible <bruno@clisp.org> parents: 9285 diff changeset	7 (at your option) any later version.
9282 9a26e94f946a New module 'trunc'. Bruno Haible <bruno@clisp.org> parents: diff changeset	8
9a26e94f946a New module 'trunc'. Bruno Haible <bruno@clisp.org> parents: diff changeset	9 This program is distributed in the hope that it will be useful,
9a26e94f946a New module 'trunc'. Bruno Haible <bruno@clisp.org> parents: diff changeset	10 but WITHOUT ANY WARRANTY; without even the implied warranty of
9a26e94f946a New module 'trunc'. Bruno Haible <bruno@clisp.org> parents: diff changeset	11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
9a26e94f946a New module 'trunc'. Bruno Haible <bruno@clisp.org> parents: diff changeset	12 GNU General Public License for more details.
9a26e94f946a New module 'trunc'. Bruno Haible <bruno@clisp.org> parents: diff changeset	13
9309 bbbbbf4cd1c5 Change copyright notice from GPLv2+ to GPLv3+. Bruno Haible <bruno@clisp.org> parents: 9285 diff changeset	14 You should have received a copy of the GNU General Public License
bbbbbf4cd1c5 Change copyright notice from GPLv2+ to GPLv3+. Bruno Haible <bruno@clisp.org> parents: 9285 diff changeset	15 along with this program. If not, see <http://www.gnu.org/licenses/>. */
9282 9a26e94f946a New module 'trunc'. Bruno Haible <bruno@clisp.org> parents: diff changeset	16
9a26e94f946a New module 'trunc'. Bruno Haible <bruno@clisp.org> parents: diff changeset	17 /* Written by Bruno Haible <bruno@clisp.org>, 2007. */
9a26e94f946a New module 'trunc'. Bruno Haible <bruno@clisp.org> parents: diff changeset	18
15926 23d150bba2eb truncl: Simplify for platforms where 'long double' == 'double'. Bruno Haible <bruno@clisp.org> parents: 14079 diff changeset	19 #if ! defined USE_LONG_DOUBLE
23d150bba2eb truncl: Simplify for platforms where 'long double' == 'double'. Bruno Haible <bruno@clisp.org> parents: 14079 diff changeset	20 # include <config.h>
23d150bba2eb truncl: Simplify for platforms where 'long double' == 'double'. Bruno Haible <bruno@clisp.org> parents: 14079 diff changeset	21 #endif
9282 9a26e94f946a New module 'trunc'. Bruno Haible <bruno@clisp.org> parents: diff changeset	22
9a26e94f946a New module 'trunc'. Bruno Haible <bruno@clisp.org> parents: diff changeset	23 /* Specification. */
9a26e94f946a New module 'trunc'. Bruno Haible <bruno@clisp.org> parents: diff changeset	24 #include <math.h>
9a26e94f946a New module 'trunc'. Bruno Haible <bruno@clisp.org> parents: diff changeset	25
9a26e94f946a New module 'trunc'. Bruno Haible <bruno@clisp.org> parents: diff changeset	26 #include <float.h>
9a26e94f946a New module 'trunc'. Bruno Haible <bruno@clisp.org> parents: diff changeset	27
14018 ac9f59901721 ceil, trunc, round: Fix gcc warnings. Bruno Haible <bruno@clisp.org> parents: 13993 diff changeset	28 #undef MIN
ac9f59901721 ceil, trunc, round: Fix gcc warnings. Bruno Haible <bruno@clisp.org> parents: 13993 diff changeset	29
9285 79e67a783774 New module 'truncf'. Bruno Haible <bruno@clisp.org> parents: 9282 diff changeset	30 #ifdef USE_LONG_DOUBLE
79e67a783774 New module 'truncf'. Bruno Haible <bruno@clisp.org> parents: 9282 diff changeset	31 # define FUNC truncl
79e67a783774 New module 'truncf'. Bruno Haible <bruno@clisp.org> parents: 9282 diff changeset	32 # define DOUBLE long double
79e67a783774 New module 'truncf'. Bruno Haible <bruno@clisp.org> parents: 9282 diff changeset	33 # define MANT_DIG LDBL_MANT_DIG
13993 9e9aaf4c9464 trunc: Implement result sign according to IEEE 754. Bruno Haible <bruno@clisp.org> parents: 12559 diff changeset	34 # define MIN LDBL_MIN
9285 79e67a783774 New module 'truncf'. Bruno Haible <bruno@clisp.org> parents: 9282 diff changeset	35 # define L_(literal) literal##L
79e67a783774 New module 'truncf'. Bruno Haible <bruno@clisp.org> parents: 9282 diff changeset	36 #elif ! defined USE_FLOAT
79e67a783774 New module 'truncf'. Bruno Haible <bruno@clisp.org> parents: 9282 diff changeset	37 # define FUNC trunc
79e67a783774 New module 'truncf'. Bruno Haible <bruno@clisp.org> parents: 9282 diff changeset	38 # define DOUBLE double
79e67a783774 New module 'truncf'. Bruno Haible <bruno@clisp.org> parents: 9282 diff changeset	39 # define MANT_DIG DBL_MANT_DIG
13993 9e9aaf4c9464 trunc: Implement result sign according to IEEE 754. Bruno Haible <bruno@clisp.org> parents: 12559 diff changeset	40 # define MIN DBL_MIN
9285 79e67a783774 New module 'truncf'. Bruno Haible <bruno@clisp.org> parents: 9282 diff changeset	41 # define L_(literal) literal
79e67a783774 New module 'truncf'. Bruno Haible <bruno@clisp.org> parents: 9282 diff changeset	42 #else /* defined USE_FLOAT */
79e67a783774 New module 'truncf'. Bruno Haible <bruno@clisp.org> parents: 9282 diff changeset	43 # define FUNC truncf
79e67a783774 New module 'truncf'. Bruno Haible <bruno@clisp.org> parents: 9282 diff changeset	44 # define DOUBLE float
79e67a783774 New module 'truncf'. Bruno Haible <bruno@clisp.org> parents: 9282 diff changeset	45 # define MANT_DIG FLT_MANT_DIG
13993 9e9aaf4c9464 trunc: Implement result sign according to IEEE 754. Bruno Haible <bruno@clisp.org> parents: 12559 diff changeset	46 # define MIN FLT_MIN
9285 79e67a783774 New module 'truncf'. Bruno Haible <bruno@clisp.org> parents: 9282 diff changeset	47 # define L_(literal) literal##f
79e67a783774 New module 'truncf'. Bruno Haible <bruno@clisp.org> parents: 9282 diff changeset	48 #endif
79e67a783774 New module 'truncf'. Bruno Haible <bruno@clisp.org> parents: 9282 diff changeset	49
13993 9e9aaf4c9464 trunc: Implement result sign according to IEEE 754. Bruno Haible <bruno@clisp.org> parents: 12559 diff changeset	50 /* -0.0. See minus-zero.h. */
9e9aaf4c9464 trunc: Implement result sign according to IEEE 754. Bruno Haible <bruno@clisp.org> parents: 12559 diff changeset	51 #if defined __hpux \|\| defined __sgi \|\| defined __ICC
9e9aaf4c9464 trunc: Implement result sign according to IEEE 754. Bruno Haible <bruno@clisp.org> parents: 12559 diff changeset	52 # define MINUS_ZERO (-MIN * MIN)
9e9aaf4c9464 trunc: Implement result sign according to IEEE 754. Bruno Haible <bruno@clisp.org> parents: 12559 diff changeset	53 #else
9e9aaf4c9464 trunc: Implement result sign according to IEEE 754. Bruno Haible <bruno@clisp.org> parents: 12559 diff changeset	54 # define MINUS_ZERO L_(-0.0)
9e9aaf4c9464 trunc: Implement result sign according to IEEE 754. Bruno Haible <bruno@clisp.org> parents: 12559 diff changeset	55 #endif
9e9aaf4c9464 trunc: Implement result sign according to IEEE 754. Bruno Haible <bruno@clisp.org> parents: 12559 diff changeset	56
9285 79e67a783774 New module 'truncf'. Bruno Haible <bruno@clisp.org> parents: 9282 diff changeset	57 /* 2^(MANT_DIG-1). */
9313 59fc463c9868 Fix type of TWO_MANT_DIG. Bruno Haible <bruno@clisp.org> parents: 9309 diff changeset	58 static const DOUBLE TWO_MANT_DIG =
9285 79e67a783774 New module 'truncf'. Bruno Haible <bruno@clisp.org> parents: 9282 diff changeset	59 /* Assume MANT_DIG <= 5 * 31.
9282 9a26e94f946a New module 'trunc'. Bruno Haible <bruno@clisp.org> parents: diff changeset	60 Use the identity
9285 79e67a783774 New module 'truncf'. Bruno Haible <bruno@clisp.org> parents: 9282 diff changeset	61 n = floor(n/5) + floor((n+1)/5) + ... + floor((n+4)/5). */
79e67a783774 New module 'truncf'. Bruno Haible <bruno@clisp.org> parents: 9282 diff changeset	62 (DOUBLE) (1U << ((MANT_DIG - 1) / 5))
79e67a783774 New module 'truncf'. Bruno Haible <bruno@clisp.org> parents: 9282 diff changeset	63 * (DOUBLE) (1U << ((MANT_DIG - 1 + 1) / 5))
79e67a783774 New module 'truncf'. Bruno Haible <bruno@clisp.org> parents: 9282 diff changeset	64 * (DOUBLE) (1U << ((MANT_DIG - 1 + 2) / 5))
79e67a783774 New module 'truncf'. Bruno Haible <bruno@clisp.org> parents: 9282 diff changeset	65 * (DOUBLE) (1U << ((MANT_DIG - 1 + 3) / 5))
79e67a783774 New module 'truncf'. Bruno Haible <bruno@clisp.org> parents: 9282 diff changeset	66 * (DOUBLE) (1U << ((MANT_DIG - 1 + 4) / 5));
9282 9a26e94f946a New module 'trunc'. Bruno Haible <bruno@clisp.org> parents: diff changeset	67
9285 79e67a783774 New module 'truncf'. Bruno Haible <bruno@clisp.org> parents: 9282 diff changeset	68 DOUBLE
79e67a783774 New module 'truncf'. Bruno Haible <bruno@clisp.org> parents: 9282 diff changeset	69 FUNC (DOUBLE x)
9282 9a26e94f946a New module 'trunc'. Bruno Haible <bruno@clisp.org> parents: diff changeset	70 {
9a26e94f946a New module 'trunc'. Bruno Haible <bruno@clisp.org> parents: diff changeset	71 /* The use of 'volatile' guarantees that excess precision bits are dropped
9a26e94f946a New module 'trunc'. Bruno Haible <bruno@clisp.org> parents: diff changeset	72 at each addition step and before the following comparison at the caller's
9a26e94f946a New module 'trunc'. Bruno Haible <bruno@clisp.org> parents: diff changeset	73 site. It is necessary on x86 systems where double-floats are not IEEE
9a26e94f946a New module 'trunc'. Bruno Haible <bruno@clisp.org> parents: diff changeset	74 compliant by default, to avoid that the results become platform and compiler
9a26e94f946a New module 'trunc'. Bruno Haible <bruno@clisp.org> parents: diff changeset	75 option dependent. 'volatile' is a portable alternative to gcc's
9a26e94f946a New module 'trunc'. Bruno Haible <bruno@clisp.org> parents: diff changeset	76 -ffloat-store option. */
9285 79e67a783774 New module 'truncf'. Bruno Haible <bruno@clisp.org> parents: 9282 diff changeset	77 volatile DOUBLE y = x;
79e67a783774 New module 'truncf'. Bruno Haible <bruno@clisp.org> parents: 9282 diff changeset	78 volatile DOUBLE z = y;
9282 9a26e94f946a New module 'trunc'. Bruno Haible <bruno@clisp.org> parents: diff changeset	79
9285 79e67a783774 New module 'truncf'. Bruno Haible <bruno@clisp.org> parents: 9282 diff changeset	80 if (z > L_(0.0))
9282 9a26e94f946a New module 'trunc'. Bruno Haible <bruno@clisp.org> parents: diff changeset	81 {
13993 9e9aaf4c9464 trunc: Implement result sign according to IEEE 754. Bruno Haible <bruno@clisp.org> parents: 12559 diff changeset	82 /* For 0 < x < 1, return +0.0 even if the current rounding mode is
9e9aaf4c9464 trunc: Implement result sign according to IEEE 754. Bruno Haible <bruno@clisp.org> parents: 12559 diff changeset	83 FE_DOWNWARD. */
9e9aaf4c9464 trunc: Implement result sign according to IEEE 754. Bruno Haible <bruno@clisp.org> parents: 12559 diff changeset	84 if (z < L_(1.0))
9e9aaf4c9464 trunc: Implement result sign according to IEEE 754. Bruno Haible <bruno@clisp.org> parents: 12559 diff changeset	85 z = L_(0.0);
9327 5437ef3873b5 Fix incorrect rounding of trunc, truncf, truncl in some cases. Add a new test. Bruno Haible <bruno@clisp.org> parents: 9313 diff changeset	86 /* Avoid rounding errors for values near 2^k, where k >= MANT_DIG-1. */
13993 9e9aaf4c9464 trunc: Implement result sign according to IEEE 754. Bruno Haible <bruno@clisp.org> parents: 12559 diff changeset	87 else if (z < TWO_MANT_DIG)
12421 e8d2c6fc33ad Use spaces for indentation, not tabs. Bruno Haible <bruno@clisp.org> parents: 9327 diff changeset	88 {
e8d2c6fc33ad Use spaces for indentation, not tabs. Bruno Haible <bruno@clisp.org> parents: 9327 diff changeset	89 /* Round to the next integer (nearest or up or down, doesn't matter). */
e8d2c6fc33ad Use spaces for indentation, not tabs. Bruno Haible <bruno@clisp.org> parents: 9327 diff changeset	90 z += TWO_MANT_DIG;
e8d2c6fc33ad Use spaces for indentation, not tabs. Bruno Haible <bruno@clisp.org> parents: 9327 diff changeset	91 z -= TWO_MANT_DIG;
e8d2c6fc33ad Use spaces for indentation, not tabs. Bruno Haible <bruno@clisp.org> parents: 9327 diff changeset	92 /* Enforce rounding down. */
e8d2c6fc33ad Use spaces for indentation, not tabs. Bruno Haible <bruno@clisp.org> parents: 9327 diff changeset	93 if (z > y)
e8d2c6fc33ad Use spaces for indentation, not tabs. Bruno Haible <bruno@clisp.org> parents: 9327 diff changeset	94 z -= L_(1.0);
e8d2c6fc33ad Use spaces for indentation, not tabs. Bruno Haible <bruno@clisp.org> parents: 9327 diff changeset	95 }
9282 9a26e94f946a New module 'trunc'. Bruno Haible <bruno@clisp.org> parents: diff changeset	96 }
9285 79e67a783774 New module 'truncf'. Bruno Haible <bruno@clisp.org> parents: 9282 diff changeset	97 else if (z < L_(0.0))
9282 9a26e94f946a New module 'trunc'. Bruno Haible <bruno@clisp.org> parents: diff changeset	98 {
13993 9e9aaf4c9464 trunc: Implement result sign according to IEEE 754. Bruno Haible <bruno@clisp.org> parents: 12559 diff changeset	99 /* For -1 < x < 0, return -0.0 regardless of the current rounding
9e9aaf4c9464 trunc: Implement result sign according to IEEE 754. Bruno Haible <bruno@clisp.org> parents: 12559 diff changeset	100 mode. */
9e9aaf4c9464 trunc: Implement result sign according to IEEE 754. Bruno Haible <bruno@clisp.org> parents: 12559 diff changeset	101 if (z > L_(-1.0))
9e9aaf4c9464 trunc: Implement result sign according to IEEE 754. Bruno Haible <bruno@clisp.org> parents: 12559 diff changeset	102 z = MINUS_ZERO;
9327 5437ef3873b5 Fix incorrect rounding of trunc, truncf, truncl in some cases. Add a new test. Bruno Haible <bruno@clisp.org> parents: 9313 diff changeset	103 /* Avoid rounding errors for values near -2^k, where k >= MANT_DIG-1. */
13993 9e9aaf4c9464 trunc: Implement result sign according to IEEE 754. Bruno Haible <bruno@clisp.org> parents: 12559 diff changeset	104 else if (z > - TWO_MANT_DIG)
12421 e8d2c6fc33ad Use spaces for indentation, not tabs. Bruno Haible <bruno@clisp.org> parents: 9327 diff changeset	105 {
e8d2c6fc33ad Use spaces for indentation, not tabs. Bruno Haible <bruno@clisp.org> parents: 9327 diff changeset	106 /* Round to the next integer (nearest or up or down, doesn't matter). */
e8d2c6fc33ad Use spaces for indentation, not tabs. Bruno Haible <bruno@clisp.org> parents: 9327 diff changeset	107 z -= TWO_MANT_DIG;
e8d2c6fc33ad Use spaces for indentation, not tabs. Bruno Haible <bruno@clisp.org> parents: 9327 diff changeset	108 z += TWO_MANT_DIG;
e8d2c6fc33ad Use spaces for indentation, not tabs. Bruno Haible <bruno@clisp.org> parents: 9327 diff changeset	109 /* Enforce rounding up. */
e8d2c6fc33ad Use spaces for indentation, not tabs. Bruno Haible <bruno@clisp.org> parents: 9327 diff changeset	110 if (z < y)
e8d2c6fc33ad Use spaces for indentation, not tabs. Bruno Haible <bruno@clisp.org> parents: 9327 diff changeset	111 z += L_(1.0);
e8d2c6fc33ad Use spaces for indentation, not tabs. Bruno Haible <bruno@clisp.org> parents: 9327 diff changeset	112 }
9282 9a26e94f946a New module 'trunc'. Bruno Haible <bruno@clisp.org> parents: diff changeset	113 }
9a26e94f946a New module 'trunc'. Bruno Haible <bruno@clisp.org> parents: diff changeset	114 return z;
9a26e94f946a New module 'trunc'. Bruno Haible <bruno@clisp.org> parents: diff changeset	115 }

Mercurial > hg > octave-lojdl > gnulib-hg

annotate lib/trunc.c @ 15926:23d150bba2eb