Replace the ldexp() implementation in libc with a renamed copy of the
scalbn() implementation from libm. (The two functions are defined to be identical, but ldexp() lives in libc for backwards compatibility.) The old ldexp() implementation... - was more complicated than this one - set errno instead of raising FP exceptions - got some corner cases wrong (e.g. ldexp(1.0, 2000) in round-to-zero mode) The new implementation lives in libc/gen instead of libc/$MACHINE_ARCH/gen, since we don't need N copies of a machine-independent file. The amd64 and i386 platforms retain their fast and correct MD implementations and override this one.
This commit is contained in:
parent
4d28b4d206
commit
00646ca204
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=140607
@ -1,137 +0,0 @@
|
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/*
|
||||
* Copyright (c) 1994, 1995 Carnegie-Mellon University.
|
||||
* All rights reserved.
|
||||
*
|
||||
* Author: Chris G. Demetriou
|
||||
*
|
||||
* Permission to use, copy, modify and distribute this software and
|
||||
* its documentation is hereby granted, provided that both the copyright
|
||||
* notice and this permission notice appear in all copies of the
|
||||
* software, derivative works or modified versions, and any portions
|
||||
* thereof, and that both notices appear in supporting documentation.
|
||||
*
|
||||
* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
|
||||
* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
|
||||
* FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
|
||||
*
|
||||
* Carnegie Mellon requests users of this software to return to
|
||||
*
|
||||
* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
|
||||
* School of Computer Science
|
||||
* Carnegie Mellon University
|
||||
* Pittsburgh PA 15213-3890
|
||||
*
|
||||
* any improvements or extensions that they make and grant Carnegie the
|
||||
* rights to redistribute these changes.
|
||||
*
|
||||
* $NetBSD: ldexp.c,v 1.1 1995/02/10 17:50:24 cgd Exp $
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/types.h>
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#include <machine/ieee.h>
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#include <errno.h>
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#include <math.h>
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|
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/*
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* double ldexp(double val, int exp)
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* returns: val * (2**exp)
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*/
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double
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ldexp(val, exp)
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double val;
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int exp;
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{
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int oldexp, newexp, mulexp;
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union doub {
|
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double v;
|
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struct ieee_double s;
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} u, mul;
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|
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/*
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* If input is zero, or no change, just return input.
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* Likewise, if input is Inf or NaN, just return it.
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*/
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u.v = val;
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oldexp = u.s.dbl_exp;
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if (val == 0 || exp == 0 || oldexp == DBL_EXP_INFNAN)
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return (val);
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/*
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* Compute new exponent and check for over/under flow.
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* Underflow, unfortunately, could mean switching to denormal.
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* If result out of range, set ERANGE and return 0 if too small
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* or Inf if too big, with the same sign as the input value.
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*/
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newexp = oldexp + exp;
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if (newexp >= DBL_EXP_INFNAN) {
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/* u.s.dbl_sign = val < 0; -- already set */
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u.s.dbl_exp = DBL_EXP_INFNAN;
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u.s.dbl_frach = u.s.dbl_fracl = 0;
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errno = ERANGE;
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return (u.v); /* Inf */
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}
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if (newexp <= 0) {
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/*
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* The output number is either a denormal or underflows
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* (see comments in machine/ieee.h).
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*/
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if (newexp <= -DBL_FRACBITS) {
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/* u.s.dbl_sign = val < 0; -- already set */
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u.s.dbl_exp = 0;
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u.s.dbl_frach = u.s.dbl_fracl = 0;
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errno = ERANGE;
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return (u.v); /* zero */
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}
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/*
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* We are going to produce a denorm. Our `exp' argument
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* might be as small as -2097, and we cannot compute
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* 2^-2097, so we may have to do this as many as three
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* steps (not just two, as for positive `exp's below).
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*/
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mul.v = 0;
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while (exp <= -DBL_EXP_BIAS) {
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mul.s.dbl_exp = 1;
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val *= mul.v;
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exp += DBL_EXP_BIAS - 1;
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}
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mul.s.dbl_exp = exp + DBL_EXP_BIAS;
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val *= mul.v;
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return (val);
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}
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/*
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* Newexp is positive.
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*
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* If oldexp is zero, we are starting with a denorm, and simply
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* adjusting the exponent will produce bogus answers. We need
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* to fix that first.
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*/
|
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if (oldexp == 0) {
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/*
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* Multiply by 2^mulexp to make the number normalizable.
|
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* We cannot multiply by more than 2^1023, but `exp'
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* argument might be as large as 2046. A single
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* adjustment, however, will normalize the number even
|
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* for huge `exp's, and then we can use exponent
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* arithmetic just as for normal `double's.
|
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*/
|
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mulexp = exp <= DBL_EXP_BIAS ? exp : DBL_EXP_BIAS;
|
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mul.v = 0;
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mul.s.dbl_exp = mulexp + DBL_EXP_BIAS;
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val *= mul.v;
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if (mulexp == exp)
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return (val);
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u.v = val;
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newexp -= mulexp;
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}
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|
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/*
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* Both oldexp and newexp are positive; just replace the
|
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* old exponent with the new one.
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*/
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u.s.dbl_exp = newexp;
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return (u.v);
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}
|
@ -1,155 +0,0 @@
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/*-
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* Copyright (c) 1999 The NetBSD Foundation, Inc.
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* All rights reserved.
|
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*
|
||||
* This code is derived from software contributed to The NetBSD Foundation
|
||||
* by Charles M. Hannum.
|
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*
|
||||
* Redistribution and use in source and binary forms, with or without
|
||||
* modification, are permitted provided that the following conditions
|
||||
* are met:
|
||||
* 1. Redistributions of source code must retain the above copyright
|
||||
* notice, this list of conditions and the following disclaimer.
|
||||
* 2. Redistributions in binary form must reproduce the above copyright
|
||||
* notice, this list of conditions and the following disclaimer in the
|
||||
* documentation and/or other materials provided with the distribution.
|
||||
* 3. All advertising materials mentioning features or use of this software
|
||||
* must display the following acknowledgement:
|
||||
* This product includes software developed by the NetBSD
|
||||
* Foundation, Inc. and its contributors.
|
||||
* 4. Neither the name of The NetBSD Foundation nor the names of its
|
||||
* contributors may be used to endorse or promote products derived
|
||||
* from this software without specific prior written permission.
|
||||
*
|
||||
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
|
||||
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
|
||||
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
|
||||
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
|
||||
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
|
||||
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
|
||||
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
|
||||
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
|
||||
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
|
||||
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
|
||||
* POSSIBILITY OF SUCH DAMAGE.
|
||||
*/
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#include <sys/cdefs.h>
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#if 0
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#if defined(LIBC_SCCS) && !defined(lint)
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__RCSID("$NetBSD: ldexp.c,v 1.8 1999/08/30 18:28:26 mycroft Exp $");
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#endif /* LIBC_SCCS and not lint */
|
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#endif
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__FBSDID("$FreeBSD$");
|
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|
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#include <sys/types.h>
|
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#include <errno.h>
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#include <math.h>
|
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#include <machine/ieee.h>
|
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|
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/*
|
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* Multiply the given value by 2^exp.
|
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*/
|
||||
double
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ldexp(val, exp)
|
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double val;
|
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int exp;
|
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{
|
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int oldexp, newexp;
|
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union {
|
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double v;
|
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struct ieee_double s;
|
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} u, mul;
|
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|
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u.v = val;
|
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oldexp = u.s.dbl_exp;
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|
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/*
|
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* If input is zero, Inf or NaN, just return it.
|
||||
*/
|
||||
if (u.v == 0.0 || oldexp == DBL_EXP_INFNAN)
|
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return (val);
|
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|
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if (oldexp == 0) {
|
||||
/*
|
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* u.v is denormal. We must adjust it so that the exponent
|
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* arithmetic below will work.
|
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*/
|
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if (exp <= DBL_EXP_BIAS) {
|
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/*
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* Optimization: if the scaling can be done in a single
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* multiply, or underflows, just do it now.
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*/
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if (exp <= -DBL_FRACBITS) {
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errno = ERANGE;
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return (0.0);
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}
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mul.v = 0.0;
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mul.s.dbl_exp = exp + DBL_EXP_BIAS;
|
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u.v *= mul.v;
|
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if (u.v == 0.0) {
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errno = ERANGE;
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return (0.0);
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}
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return (u.v);
|
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} else {
|
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/*
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* We know that exp is very large, and therefore the
|
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* result cannot be denormal (though it may be Inf).
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* Shift u.v by just enough to make it normal.
|
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*/
|
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mul.v = 0.0;
|
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mul.s.dbl_exp = DBL_FRACBITS + DBL_EXP_BIAS;
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u.v *= mul.v;
|
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exp -= DBL_FRACBITS;
|
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oldexp = u.s.dbl_exp;
|
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}
|
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}
|
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|
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/*
|
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* u.v is now normalized and oldexp has been adjusted if necessary.
|
||||
* Calculate the new exponent and check for underflow and overflow.
|
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*/
|
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newexp = oldexp + exp;
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|
||||
if (newexp <= 0) {
|
||||
/*
|
||||
* The output number is either denormal or underflows (see
|
||||
* comments in machine/ieee.h).
|
||||
*/
|
||||
if (newexp <= -DBL_FRACBITS) {
|
||||
errno = ERANGE;
|
||||
return (0.0);
|
||||
}
|
||||
/*
|
||||
* Denormalize the result. We do this with a multiply. If exp
|
||||
* is very large, it won't fit in a double, so we have to
|
||||
* adjust the exponent first. This is safe because we know
|
||||
* that u.v is normal at this point.
|
||||
*/
|
||||
if (exp <= -DBL_EXP_BIAS) {
|
||||
u.s.dbl_exp = 1;
|
||||
exp += oldexp - 1;
|
||||
}
|
||||
mul.v = 0.0;
|
||||
mul.s.dbl_exp = exp + DBL_EXP_BIAS;
|
||||
u.v *= mul.v;
|
||||
return (u.v);
|
||||
} else if (newexp >= DBL_EXP_INFNAN) {
|
||||
/*
|
||||
* The result overflowed; return +/-Inf.
|
||||
*/
|
||||
u.s.dbl_exp = DBL_EXP_INFNAN;
|
||||
u.s.dbl_frach = 0;
|
||||
u.s.dbl_fracl = 0;
|
||||
errno = ERANGE;
|
||||
return (u.v);
|
||||
} else {
|
||||
/*
|
||||
* The result is normal; just replace the old exponent with the
|
||||
* new one.
|
||||
*/
|
||||
u.s.dbl_exp = newexp;
|
||||
return (u.v);
|
||||
}
|
||||
}
|
123
lib/libc/gen/ldexp.c
Normal file
123
lib/libc/gen/ldexp.c
Normal file
@ -0,0 +1,123 @@
|
||||
/* @(#)s_scalbn.c 5.1 93/09/24 */
|
||||
/* @(#)fdlibm.h 5.1 93/09/24 */
|
||||
/*
|
||||
* ====================================================
|
||||
* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
|
||||
*
|
||||
* Developed at SunPro, a Sun Microsystems, Inc. business.
|
||||
* Permission to use, copy, modify, and distribute this
|
||||
* software is freely granted, provided that this notice
|
||||
* is preserved.
|
||||
* ====================================================
|
||||
*/
|
||||
|
||||
#include <sys/cdefs.h>
|
||||
__FBSDID("$FreeBSD$");
|
||||
|
||||
#include <sys/types.h>
|
||||
#include <machine/endian.h>
|
||||
#include <math.h>
|
||||
|
||||
/* Bit fiddling routines copied from msun/src/math_private.h,v 1.15 */
|
||||
|
||||
#if BYTE_ORDER == BIG_ENDIAN
|
||||
|
||||
typedef union
|
||||
{
|
||||
double value;
|
||||
struct
|
||||
{
|
||||
u_int32_t msw;
|
||||
u_int32_t lsw;
|
||||
} parts;
|
||||
} ieee_double_shape_type;
|
||||
|
||||
#endif
|
||||
|
||||
#if BYTE_ORDER == LITTLE_ENDIAN
|
||||
|
||||
typedef union
|
||||
{
|
||||
double value;
|
||||
struct
|
||||
{
|
||||
u_int32_t lsw;
|
||||
u_int32_t msw;
|
||||
} parts;
|
||||
} ieee_double_shape_type;
|
||||
|
||||
#endif
|
||||
|
||||
/* Get two 32 bit ints from a double. */
|
||||
|
||||
#define EXTRACT_WORDS(ix0,ix1,d) \
|
||||
do { \
|
||||
ieee_double_shape_type ew_u; \
|
||||
ew_u.value = (d); \
|
||||
(ix0) = ew_u.parts.msw; \
|
||||
(ix1) = ew_u.parts.lsw; \
|
||||
} while (0)
|
||||
|
||||
/* Get the more significant 32 bit int from a double. */
|
||||
|
||||
#define GET_HIGH_WORD(i,d) \
|
||||
do { \
|
||||
ieee_double_shape_type gh_u; \
|
||||
gh_u.value = (d); \
|
||||
(i) = gh_u.parts.msw; \
|
||||
} while (0)
|
||||
|
||||
/* Set the more significant 32 bits of a double from an int. */
|
||||
|
||||
#define SET_HIGH_WORD(d,v) \
|
||||
do { \
|
||||
ieee_double_shape_type sh_u; \
|
||||
sh_u.value = (d); \
|
||||
sh_u.parts.msw = (v); \
|
||||
(d) = sh_u.value; \
|
||||
} while (0)
|
||||
|
||||
|
||||
static const double
|
||||
two54 = 1.80143985094819840000e+16, /* 0x43500000, 0x00000000 */
|
||||
twom54 = 5.55111512312578270212e-17, /* 0x3C900000, 0x00000000 */
|
||||
huge = 1.0e+300,
|
||||
tiny = 1.0e-300;
|
||||
|
||||
static double
|
||||
_copysign(double x, double y)
|
||||
{
|
||||
u_int32_t hx,hy;
|
||||
GET_HIGH_WORD(hx,x);
|
||||
GET_HIGH_WORD(hy,y);
|
||||
SET_HIGH_WORD(x,(hx&0x7fffffff)|(hy&0x80000000));
|
||||
return x;
|
||||
}
|
||||
|
||||
double
|
||||
ldexp(double x, int n)
|
||||
{
|
||||
int32_t k,hx,lx;
|
||||
EXTRACT_WORDS(hx,lx,x);
|
||||
k = (hx&0x7ff00000)>>20; /* extract exponent */
|
||||
if (k==0) { /* 0 or subnormal x */
|
||||
if ((lx|(hx&0x7fffffff))==0) return x; /* +-0 */
|
||||
x *= two54;
|
||||
GET_HIGH_WORD(hx,x);
|
||||
k = ((hx&0x7ff00000)>>20) - 54;
|
||||
if (n< -50000) return tiny*x; /*underflow*/
|
||||
}
|
||||
if (k==0x7ff) return x+x; /* NaN or Inf */
|
||||
k = k+n;
|
||||
if (k > 0x7fe) return huge*_copysign(huge,x); /* overflow */
|
||||
if (k > 0) /* normal result */
|
||||
{SET_HIGH_WORD(x,(hx&0x800fffff)|(k<<20)); return x;}
|
||||
if (k <= -54) {
|
||||
if (n > 50000) /* in case integer overflow in n+k */
|
||||
return huge*_copysign(huge,x); /*overflow*/
|
||||
else return tiny*_copysign(tiny,x); /*underflow*/
|
||||
}
|
||||
k += 54; /* subnormal result */
|
||||
SET_HIGH_WORD(x,(hx&0x800fffff)|(k<<20));
|
||||
return x*twom54;
|
||||
}
|
@ -1,137 +0,0 @@
|
||||
/* $NetBSD: ldexp.c,v 1.1 1995/02/10 17:50:24 cgd Exp $ */
|
||||
|
||||
/*
|
||||
* Copyright (c) 1994, 1995 Carnegie-Mellon University.
|
||||
* All rights reserved.
|
||||
*
|
||||
* Author: Chris G. Demetriou
|
||||
*
|
||||
* Permission to use, copy, modify and distribute this software and
|
||||
* its documentation is hereby granted, provided that both the copyright
|
||||
* notice and this permission notice appear in all copies of the
|
||||
* software, derivative works or modified versions, and any portions
|
||||
* thereof, and that both notices appear in supporting documentation.
|
||||
*
|
||||
* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
|
||||
* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
|
||||
* FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
|
||||
*
|
||||
* Carnegie Mellon requests users of this software to return to
|
||||
*
|
||||
* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
|
||||
* School of Computer Science
|
||||
* Carnegie Mellon University
|
||||
* Pittsburgh PA 15213-3890
|
||||
*
|
||||
* any improvements or extensions that they make and grant Carnegie the
|
||||
* rights to redistribute these changes.
|
||||
*/
|
||||
|
||||
#include <sys/cdefs.h>
|
||||
__FBSDID("$FreeBSD$");
|
||||
|
||||
#include <sys/types.h>
|
||||
#include <machine/ieee.h>
|
||||
#include <errno.h>
|
||||
#include <math.h>
|
||||
|
||||
/*
|
||||
* double ldexp(double val, int exp)
|
||||
* returns: val * (2**exp)
|
||||
*/
|
||||
double
|
||||
ldexp(val, exp)
|
||||
double val;
|
||||
int exp;
|
||||
{
|
||||
int oldexp, newexp, mulexp;
|
||||
union doub {
|
||||
double v;
|
||||
struct ieee_double s;
|
||||
} u, mul;
|
||||
|
||||
/*
|
||||
* If input is zero, or no change, just return input.
|
||||
* Likewise, if input is Inf or NaN, just return it.
|
||||
*/
|
||||
u.v = val;
|
||||
oldexp = u.s.dbl_exp;
|
||||
if (val == 0 || exp == 0 || oldexp == DBL_EXP_INFNAN)
|
||||
return (val);
|
||||
|
||||
/*
|
||||
* Compute new exponent and check for over/under flow.
|
||||
* Underflow, unfortunately, could mean switching to denormal.
|
||||
* If result out of range, set ERANGE and return 0 if too small
|
||||
* or Inf if too big, with the same sign as the input value.
|
||||
*/
|
||||
newexp = oldexp + exp;
|
||||
if (newexp >= DBL_EXP_INFNAN) {
|
||||
/* u.s.dbl_sign = val < 0; -- already set */
|
||||
u.s.dbl_exp = DBL_EXP_INFNAN;
|
||||
u.s.dbl_frach = u.s.dbl_fracl = 0;
|
||||
errno = ERANGE;
|
||||
return (u.v); /* Inf */
|
||||
}
|
||||
if (newexp <= 0) {
|
||||
/*
|
||||
* The output number is either a denormal or underflows
|
||||
* (see comments in machine/ieee.h).
|
||||
*/
|
||||
if (newexp <= -DBL_FRACBITS) {
|
||||
/* u.s.dbl_sign = val < 0; -- already set */
|
||||
u.s.dbl_exp = 0;
|
||||
u.s.dbl_frach = u.s.dbl_fracl = 0;
|
||||
errno = ERANGE;
|
||||
return (u.v); /* zero */
|
||||
}
|
||||
/*
|
||||
* We are going to produce a denorm. Our `exp' argument
|
||||
* might be as small as -2097, and we cannot compute
|
||||
* 2^-2097, so we may have to do this as many as three
|
||||
* steps (not just two, as for positive `exp's below).
|
||||
*/
|
||||
mul.v = 0;
|
||||
while (exp <= -DBL_EXP_BIAS) {
|
||||
mul.s.dbl_exp = 1;
|
||||
val *= mul.v;
|
||||
exp += DBL_EXP_BIAS - 1;
|
||||
}
|
||||
mul.s.dbl_exp = exp + DBL_EXP_BIAS;
|
||||
val *= mul.v;
|
||||
return (val);
|
||||
}
|
||||
|
||||
/*
|
||||
* Newexp is positive.
|
||||
*
|
||||
* If oldexp is zero, we are starting with a denorm, and simply
|
||||
* adjusting the exponent will produce bogus answers. We need
|
||||
* to fix that first.
|
||||
*/
|
||||
if (oldexp == 0) {
|
||||
/*
|
||||
* Multiply by 2^mulexp to make the number normalizable.
|
||||
* We cannot multiply by more than 2^1023, but `exp'
|
||||
* argument might be as large as 2046. A single
|
||||
* adjustment, however, will normalize the number even
|
||||
* for huge `exp's, and then we can use exponent
|
||||
* arithmetic just as for normal `double's.
|
||||
*/
|
||||
mulexp = exp <= DBL_EXP_BIAS ? exp : DBL_EXP_BIAS;
|
||||
mul.v = 0;
|
||||
mul.s.dbl_exp = mulexp + DBL_EXP_BIAS;
|
||||
val *= mul.v;
|
||||
if (mulexp == exp)
|
||||
return (val);
|
||||
u.v = val;
|
||||
newexp -= mulexp;
|
||||
}
|
||||
|
||||
/*
|
||||
* Both oldexp and newexp are positive; just replace the
|
||||
* old exponent with the new one.
|
||||
*/
|
||||
u.s.dbl_exp = newexp;
|
||||
return (u.v);
|
||||
}
|
@ -1,155 +0,0 @@
|
||||
/*-
|
||||
* Copyright (c) 1999 The NetBSD Foundation, Inc.
|
||||
* All rights reserved.
|
||||
*
|
||||
* This code is derived from software contributed to The NetBSD Foundation
|
||||
* by Charles M. Hannum.
|
||||
*
|
||||
* Redistribution and use in source and binary forms, with or without
|
||||
* modification, are permitted provided that the following conditions
|
||||
* are met:
|
||||
* 1. Redistributions of source code must retain the above copyright
|
||||
* notice, this list of conditions and the following disclaimer.
|
||||
* 2. Redistributions in binary form must reproduce the above copyright
|
||||
* notice, this list of conditions and the following disclaimer in the
|
||||
* documentation and/or other materials provided with the distribution.
|
||||
* 3. All advertising materials mentioning features or use of this software
|
||||
* must display the following acknowledgement:
|
||||
* This product includes software developed by the NetBSD
|
||||
* Foundation, Inc. and its contributors.
|
||||
* 4. Neither the name of The NetBSD Foundation nor the names of its
|
||||
* contributors may be used to endorse or promote products derived
|
||||
* from this software without specific prior written permission.
|
||||
*
|
||||
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
|
||||
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
|
||||
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
|
||||
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
|
||||
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
|
||||
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
|
||||
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
|
||||
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
|
||||
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
|
||||
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
|
||||
* POSSIBILITY OF SUCH DAMAGE.
|
||||
*/
|
||||
|
||||
#include <sys/cdefs.h>
|
||||
#if 0
|
||||
#if defined(LIBC_SCCS) && !defined(lint)
|
||||
__RCSID("$NetBSD: ldexp.c,v 1.8 1999/08/30 18:28:26 mycroft Exp $");
|
||||
#endif /* LIBC_SCCS and not lint */
|
||||
#endif
|
||||
__FBSDID("$FreeBSD$");
|
||||
|
||||
#include <sys/types.h>
|
||||
#include <machine/ieee.h>
|
||||
#include <errno.h>
|
||||
#include <math.h>
|
||||
|
||||
/*
|
||||
* Multiply the given value by 2^exp.
|
||||
*/
|
||||
double
|
||||
ldexp(val, exp)
|
||||
double val;
|
||||
int exp;
|
||||
{
|
||||
int oldexp, newexp;
|
||||
union {
|
||||
double v;
|
||||
struct ieee_double s;
|
||||
} u, mul;
|
||||
|
||||
u.v = val;
|
||||
oldexp = u.s.dbl_exp;
|
||||
|
||||
/*
|
||||
* If input is zero, Inf or NaN, just return it.
|
||||
*/
|
||||
if (u.v == 0.0 || oldexp == DBL_EXP_INFNAN)
|
||||
return (val);
|
||||
|
||||
if (oldexp == 0) {
|
||||
/*
|
||||
* u.v is denormal. We must adjust it so that the exponent
|
||||
* arithmetic below will work.
|
||||
*/
|
||||
if (exp <= DBL_EXP_BIAS) {
|
||||
/*
|
||||
* Optimization: if the scaling can be done in a single
|
||||
* multiply, or underflows, just do it now.
|
||||
*/
|
||||
if (exp <= -DBL_FRACBITS) {
|
||||
errno = ERANGE;
|
||||
return (0.0);
|
||||
}
|
||||
mul.v = 0.0;
|
||||
mul.s.dbl_exp = exp + DBL_EXP_BIAS;
|
||||
u.v *= mul.v;
|
||||
if (u.v == 0.0) {
|
||||
errno = ERANGE;
|
||||
return (0.0);
|
||||
}
|
||||
return (u.v);
|
||||
} else {
|
||||
/*
|
||||
* We know that exp is very large, and therefore the
|
||||
* result cannot be denormal (though it may be Inf).
|
||||
* Shift u.v by just enough to make it normal.
|
||||
*/
|
||||
mul.v = 0.0;
|
||||
mul.s.dbl_exp = DBL_FRACBITS + DBL_EXP_BIAS;
|
||||
u.v *= mul.v;
|
||||
exp -= DBL_FRACBITS;
|
||||
oldexp = u.s.dbl_exp;
|
||||
}
|
||||
}
|
||||
|
||||
/*
|
||||
* u.v is now normalized and oldexp has been adjusted if necessary.
|
||||
* Calculate the new exponent and check for underflow and overflow.
|
||||
*/
|
||||
newexp = oldexp + exp;
|
||||
|
||||
if (newexp <= 0) {
|
||||
/*
|
||||
* The output number is either denormal or underflows (see
|
||||
* comments in machine/ieee.h).
|
||||
*/
|
||||
if (newexp <= -DBL_FRACBITS) {
|
||||
errno = ERANGE;
|
||||
return (0.0);
|
||||
}
|
||||
/*
|
||||
* Denormalize the result. We do this with a multiply. If exp
|
||||
* is very large, it won't fit in a double, so we have to
|
||||
* adjust the exponent first. This is safe because we know
|
||||
* that u.v is normal at this point.
|
||||
*/
|
||||
if (exp <= -DBL_EXP_BIAS) {
|
||||
u.s.dbl_exp = 1;
|
||||
exp += oldexp - 1;
|
||||
}
|
||||
mul.v = 0.0;
|
||||
mul.s.dbl_exp = exp + DBL_EXP_BIAS;
|
||||
u.v *= mul.v;
|
||||
return (u.v);
|
||||
} else if (newexp >= DBL_EXP_INFNAN) {
|
||||
/*
|
||||
* The result overflowed; return +/-Inf.
|
||||
*/
|
||||
u.s.dbl_exp = DBL_EXP_INFNAN;
|
||||
u.s.dbl_frach = 0;
|
||||
u.s.dbl_fracl = 0;
|
||||
errno = ERANGE;
|
||||
return (u.v);
|
||||
} else {
|
||||
/*
|
||||
* The result is normal; just replace the old exponent with the
|
||||
* new one.
|
||||
*/
|
||||
u.s.dbl_exp = newexp;
|
||||
return (u.v);
|
||||
}
|
||||
}
|
@ -1,155 +0,0 @@
|
||||
/*-
|
||||
* Copyright (c) 1999 The NetBSD Foundation, Inc.
|
||||
* All rights reserved.
|
||||
*
|
||||
* This code is derived from software contributed to The NetBSD Foundation
|
||||
* by Charles M. Hannum.
|
||||
*
|
||||
* Redistribution and use in source and binary forms, with or without
|
||||
* modification, are permitted provided that the following conditions
|
||||
* are met:
|
||||
* 1. Redistributions of source code must retain the above copyright
|
||||
* notice, this list of conditions and the following disclaimer.
|
||||
* 2. Redistributions in binary form must reproduce the above copyright
|
||||
* notice, this list of conditions and the following disclaimer in the
|
||||
* documentation and/or other materials provided with the distribution.
|
||||
* 3. All advertising materials mentioning features or use of this software
|
||||
* must display the following acknowledgement:
|
||||
* This product includes software developed by the NetBSD
|
||||
* Foundation, Inc. and its contributors.
|
||||
* 4. Neither the name of The NetBSD Foundation nor the names of its
|
||||
* contributors may be used to endorse or promote products derived
|
||||
* from this software without specific prior written permission.
|
||||
*
|
||||
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
|
||||
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
|
||||
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
|
||||
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
|
||||
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
|
||||
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
|
||||
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
|
||||
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
|
||||
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
|
||||
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
|
||||
* POSSIBILITY OF SUCH DAMAGE.
|
||||
*/
|
||||
|
||||
#include <sys/cdefs.h>
|
||||
#if 0
|
||||
#if defined(LIBC_SCCS) && !defined(lint)
|
||||
__RCSID("$NetBSD: ldexp.c,v 1.8 1999/08/30 18:28:26 mycroft Exp $");
|
||||
#endif /* LIBC_SCCS and not lint */
|
||||
#endif
|
||||
__FBSDID("$FreeBSD$");
|
||||
|
||||
#include <sys/types.h>
|
||||
#include <machine/ieee.h>
|
||||
#include <errno.h>
|
||||
#include <math.h>
|
||||
|
||||
/*
|
||||
* Multiply the given value by 2^exp.
|
||||
*/
|
||||
double
|
||||
ldexp(val, exp)
|
||||
double val;
|
||||
int exp;
|
||||
{
|
||||
int oldexp, newexp;
|
||||
union {
|
||||
double v;
|
||||
struct ieee_double s;
|
||||
} u, mul;
|
||||
|
||||
u.v = val;
|
||||
oldexp = u.s.dbl_exp;
|
||||
|
||||
/*
|
||||
* If input is zero, Inf or NaN, just return it.
|
||||
*/
|
||||
if (u.v == 0.0 || oldexp == DBL_EXP_INFNAN)
|
||||
return (val);
|
||||
|
||||
if (oldexp == 0) {
|
||||
/*
|
||||
* u.v is denormal. We must adjust it so that the exponent
|
||||
* arithmetic below will work.
|
||||
*/
|
||||
if (exp <= DBL_EXP_BIAS) {
|
||||
/*
|
||||
* Optimization: if the scaling can be done in a single
|
||||
* multiply, or underflows, just do it now.
|
||||
*/
|
||||
if (exp <= -DBL_FRACBITS) {
|
||||
errno = ERANGE;
|
||||
return (0.0);
|
||||
}
|
||||
mul.v = 0.0;
|
||||
mul.s.dbl_exp = exp + DBL_EXP_BIAS;
|
||||
u.v *= mul.v;
|
||||
if (u.v == 0.0) {
|
||||
errno = ERANGE;
|
||||
return (0.0);
|
||||
}
|
||||
return (u.v);
|
||||
} else {
|
||||
/*
|
||||
* We know that exp is very large, and therefore the
|
||||
* result cannot be denormal (though it may be Inf).
|
||||
* Shift u.v by just enough to make it normal.
|
||||
*/
|
||||
mul.v = 0.0;
|
||||
mul.s.dbl_exp = DBL_FRACBITS + DBL_EXP_BIAS;
|
||||
u.v *= mul.v;
|
||||
exp -= DBL_FRACBITS;
|
||||
oldexp = u.s.dbl_exp;
|
||||
}
|
||||
}
|
||||
|
||||
/*
|
||||
* u.v is now normalized and oldexp has been adjusted if necessary.
|
||||
* Calculate the new exponent and check for underflow and overflow.
|
||||
*/
|
||||
newexp = oldexp + exp;
|
||||
|
||||
if (newexp <= 0) {
|
||||
/*
|
||||
* The output number is either denormal or underflows (see
|
||||
* comments in machine/ieee.h).
|
||||
*/
|
||||
if (newexp <= -DBL_FRACBITS) {
|
||||
errno = ERANGE;
|
||||
return (0.0);
|
||||
}
|
||||
/*
|
||||
* Denormalize the result. We do this with a multiply. If exp
|
||||
* is very large, it won't fit in a double, so we have to
|
||||
* adjust the exponent first. This is safe because we know
|
||||
* that u.v is normal at this point.
|
||||
*/
|
||||
if (exp <= -DBL_EXP_BIAS) {
|
||||
u.s.dbl_exp = 1;
|
||||
exp += oldexp - 1;
|
||||
}
|
||||
mul.v = 0.0;
|
||||
mul.s.dbl_exp = exp + DBL_EXP_BIAS;
|
||||
u.v *= mul.v;
|
||||
return (u.v);
|
||||
} else if (newexp >= DBL_EXP_INFNAN) {
|
||||
/*
|
||||
* The result overflowed; return +/-Inf.
|
||||
*/
|
||||
u.s.dbl_exp = DBL_EXP_INFNAN;
|
||||
u.s.dbl_frach = 0;
|
||||
u.s.dbl_fracl = 0;
|
||||
errno = ERANGE;
|
||||
return (u.v);
|
||||
} else {
|
||||
/*
|
||||
* The result is normal; just replace the old exponent with the
|
||||
* new one.
|
||||
*/
|
||||
u.s.dbl_exp = newexp;
|
||||
return (u.v);
|
||||
}
|
||||
}
|
Loading…
Reference in New Issue
Block a user