58 lines
1.8 KiB
C
58 lines
1.8 KiB
C
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/*-
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* Copyright (c) 2004 David Schultz <das@FreeBSD.ORG>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#include <math.h>
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#include "fpmath.h"
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double
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frexp(double d, int *ex)
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{
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union IEEEd2bits u;
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u.d = d;
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switch (u.bits.exp) {
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case 0: /* 0 or subnormal */
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if ((u.bits.manl | u.bits.manh) == 0) {
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*ex = 0;
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} else {
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u.d *= 0x1.0p514;
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*ex = u.bits.exp - 1536;
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u.bits.exp = 1022;
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}
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break;
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case 2047: /* infinity or NaN; value of *ex is unspecified */
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break;
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default: /* normal */
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*ex = u.bits.exp - 1022;
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u.bits.exp = 1022;
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break;
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}
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return (u.d);
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}
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