1/****************************************************************
2
3The author of this software is David M. Gay.
4
5Copyright (C) 1998, 1999 by Lucent Technologies
6All Rights Reserved
7
8Permission to use, copy, modify, and distribute this software and
9its documentation for any purpose and without fee is hereby
10granted, provided that the above copyright notice appear in all
11copies and that both that the copyright notice and this
12permission notice and warranty disclaimer appear in supporting
13documentation, and that the name of Lucent or any of its entities
14not be used in advertising or publicity pertaining to
15distribution of the software without specific, written prior
16permission.
17
18LUCENT DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
19INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS.
20IN NO EVENT SHALL LUCENT OR ANY OF ITS ENTITIES BE LIABLE FOR ANY
21SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
22WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER
23IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
24ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
25THIS SOFTWARE.
26
27****************************************************************/
28
29/* Please send bug reports to David M. Gay (dmg at acm dot org,
30 * with " at " changed at "@" and " dot " changed to ".").	*/
31
32#include "gdtoaimp.h"
33
34 double
35ulp
36#ifdef KR_headers
37	(x) U *x;
38#else
39	(U *x)
40#endif
41{
42	Long L;
43	U a;
44
45	L = (word0(x) & Exp_mask) - (P-1)*Exp_msk1;
46#ifndef Sudden_Underflow
47	if (L > 0) {
48#endif
49#ifdef IBM
50		L |= Exp_msk1 >> 4;
51#endif
52		word0(&a) = L;
53		word1(&a) = 0;
54#ifndef Sudden_Underflow
55		}
56	else {
57		L = -L >> Exp_shift;
58		if (L < Exp_shift) {
59			word0(&a) = 0x80000 >> L;
60			word1(&a) = 0;
61			}
62		else {
63			word0(&a) = 0;
64			L -= Exp_shift;
65			word1(&a) = L >= 31 ? 1 : 1 << (31 - L);
66			}
67		}
68#endif
69	return dval(&a);
70	}
71