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