зеркало из https://github.com/mozilla/pjs.git
100 строки
3.1 KiB
C
100 строки
3.1 KiB
C
/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
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*
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* ***** BEGIN LICENSE BLOCK *****
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* Version: MPL 1.1/GPL 2.0/LGPL 2.1
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*
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* The contents of this file are subject to the Mozilla Public License Version
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* 1.1 (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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* http://www.mozilla.org/MPL/
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*
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* Software distributed under the License is distributed on an "AS IS" basis,
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* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
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* for the specific language governing rights and limitations under the
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* License.
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*
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* The Original Code is Mozilla Communicator client code, released
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* March 31, 1998.
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*
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* The Initial Developer of the Original Code is
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* Sun Microsystems, Inc.
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* Portions created by the Initial Developer are Copyright (C) 1998
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* the Initial Developer. All Rights Reserved.
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*
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* Contributor(s):
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*
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* Alternatively, the contents of this file may be used under the terms of
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* either of the GNU General Public License Version 2 or later (the "GPL"),
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* or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
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* in which case the provisions of the GPL or the LGPL are applicable instead
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* of those above. If you wish to allow use of your version of this file only
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* under the terms of either the GPL or the LGPL, and not to allow others to
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* use your version of this file under the terms of the MPL, indicate your
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* decision by deleting the provisions above and replace them with the notice
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* and other provisions required by the GPL or the LGPL. If you do not delete
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* the provisions above, a recipient may use your version of this file under
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* the terms of any one of the MPL, the GPL or the LGPL.
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*
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* ***** END LICENSE BLOCK ***** */
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/* @(#)s_frexp.c 1.4 95/01/18 */
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/*
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* ====================================================
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* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
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*
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* Developed at SunSoft, a Sun Microsystems, Inc. business.
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* Permission to use, copy, modify, and distribute this
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* software is freely granted, provided that this notice
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* is preserved.
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* ====================================================
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*/
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/*
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* for non-zero x
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* x = frexp(arg,&exp);
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* return a double fp quantity x such that 0.5 <= |x| <1.0
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* and the corresponding binary exponent "exp". That is
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* arg = x*2^exp.
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* If arg is inf, 0.0, or NaN, then frexp(arg,&exp) returns arg
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* with *exp=0.
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*/
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#include "fdlibm.h"
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#ifdef __STDC__
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static const double
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#else
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static double
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#endif
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two54 = 1.80143985094819840000e+16; /* 0x43500000, 0x00000000 */
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#ifdef __STDC__
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double fd_frexp(double x, int *eptr)
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#else
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double fd_frexp(x, eptr)
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double x; int *eptr;
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#endif
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{
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int hx, ix, lx;
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fd_twoints u;
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u.d = x;
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hx = __HI(u);
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ix = 0x7fffffff&hx;
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lx = __LO(u);
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*eptr = 0;
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if(ix>=0x7ff00000||((ix|lx)==0)) return x; /* 0,inf,nan */
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if (ix<0x00100000) { /* subnormal */
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x *= two54;
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u.d = x;
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hx = __HI(u);
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ix = hx&0x7fffffff;
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*eptr = -54;
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}
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*eptr += (ix>>20)-1022;
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hx = (hx&0x800fffff)|0x3fe00000;
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u.d = x;
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__HI(u) = hx;
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x = u.d;
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return x;
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}
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