73 lines
1.9 KiB
C
73 lines
1.9 KiB
C
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/* $NetBSD: ulp.c,v 1.2 2006/01/25 15:27:42 kleink Exp $ */
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/****************************************************************
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The author of this software is David M. Gay.
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Copyright (C) 1998, 1999 by Lucent Technologies
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All Rights Reserved
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Permission to use, copy, modify, and distribute this software and
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its documentation for any purpose and without fee is hereby
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granted, provided that the above copyright notice appear in all
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copies and that both that the copyright notice and this
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permission notice and warranty disclaimer appear in supporting
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documentation, and that the name of Lucent or any of its entities
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not be used in advertising or publicity pertaining to
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distribution of the software without specific, written prior
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permission.
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LUCENT DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
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INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS.
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IN NO EVENT SHALL LUCENT OR ANY OF ITS ENTITIES BE LIABLE FOR ANY
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SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER
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IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
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ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
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THIS SOFTWARE.
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****************************************************************/
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/* Please send bug reports to David M. Gay (dmg at acm dot org,
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* with " at " changed at "@" and " dot " changed to "."). */
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#include "gdtoaimp.h"
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double
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ulp
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#ifdef KR_headers
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(x) double x;
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#else
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(double x)
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#endif
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{
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Long L;
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double a;
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L = (word0(x) & Exp_mask) - (P-1)*Exp_msk1;
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#ifndef Sudden_Underflow
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if (L > 0) {
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#endif
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#ifdef IBM
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L |= Exp_msk1 >> 4;
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#endif
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word0(a) = L;
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word1(a) = 0;
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#ifndef Sudden_Underflow
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}
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else {
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L = (unsigned int)-L >> Exp_shift;
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if (L < Exp_shift) {
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word0(a) = 0x80000 >> L;
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word1(a) = 0;
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}
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else {
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word0(a) = 0;
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L -= Exp_shift;
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word1(a) = L >= 31 ? 1 : 1 << (31 - L);
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}
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}
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#endif
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return a;
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}
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