projects / apple / libc.git / blame
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|---|---|---|
| 9385eb3d A |
1 | /**************************************************************** |
| 2 | ||
| 3 | The author of this software is David M. Gay. | |
| 4 | ||
| 5 | Copyright (C) 1998, 1999 by Lucent Technologies | |
| 6 | All Rights Reserved | |
| 7 | ||
| 8 | Permission to use, copy, modify, and distribute this software and | |
| 9 | its documentation for any purpose and without fee is hereby | |
| 10 | granted, provided that the above copyright notice appear in all | |
| 11 | copies and that both that the copyright notice and this | |
| 12 | permission notice and warranty disclaimer appear in supporting | |
| 13 | documentation, and that the name of Lucent or any of its entities | |
| 14 | not be used in advertising or publicity pertaining to | |
| 15 | distribution of the software without specific, written prior | |
| 16 | permission. | |
| 17 | ||
| 18 | LUCENT DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, | |
| 19 | INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. | |
| 20 | IN NO EVENT SHALL LUCENT OR ANY OF ITS ENTITIES BE LIABLE FOR ANY | |
| 21 | SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES | |
| 22 | WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER | |
| 23 | IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, | |
| 24 | ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF | |
| 25 | THIS SOFTWARE. | |
| 26 | ||
| 27 | ****************************************************************/ | |
| 28 | ||
| 29 | /* Please send bug reports to | |
| 30 | David M. Gay | |
| 31 | Bell Laboratories, Room 2C-463 | |
| 32 | 600 Mountain Avenue | |
| 33 | Murray Hill, NJ 07974-0636 | |
| 34 | U.S.A. | |
| 35 | dmg@bell-labs.com | |
| 36 | */ | |
| 37 | ||
| 38 | #include "gdtoaimp.h" | |
| 39 | ||
| 40 | double | |
| 41 | ulp | |
| 42 | #ifdef KR_headers | |
| 43 | (x) double x; | |
| 44 | #else | |
| 45 | (double x) | |
| 46 | #endif | |
| 47 | { | |
| 48 | Long L; | |
| 49 | double a; | |
| 50 | ||
| 51 | L = (word0(x) & Exp_mask) - (P-1)*Exp_msk1; | |
| 52 | #ifndef Sudden_Underflow | |
| 53 | if (L > 0) { | |
| 54 | #endif | |
| 55 | #ifdef IBM | |
| 56 | L |= Exp_msk1 >> 4; | |
| 57 | #endif | |
| 58 | word0(a) = L; | |
| 59 | word1(a) = 0; | |
| 60 | #ifndef Sudden_Underflow | |
| 61 | } | |
| 62 | else { | |
| 63 | L = -L >> Exp_shift; | |
| 64 | if (L < Exp_shift) { | |
| 65 | word0(a) = 0x80000 >> L; | |
| 66 | word1(a) = 0; | |
| 67 | } | |
| 68 | else { | |
| 69 | word0(a) = 0; | |
| 70 | L -= Exp_shift; | |
| 71 | word1(a) = L >= 31 ? 1 : 1 << 31 - L; | |
| 72 | } | |
| 73 | } | |
| 74 | #endif | |
| 75 | return a; | |
| 76 | } |