projects / thirdparty / glibc.git / blame
| Commit | Line | Data |
|---|---|---|
| 0413b54c UD |
1 | /* 64-bit floating point to 128-bit floating point. |
| 2 | Copyright (C) 1997 Free Software Foundation, Inc. | |
| 3 | This file is part of the GNU C Library. | |
| 4 | ||
| 5 | The GNU C Library is free software; you can redistribute it and/or | |
| 6 | modify it under the terms of the GNU Library General Public License as | |
| 7 | published by the Free Software Foundation; either version 2 of the | |
| 8 | License, or (at your option) any later version. | |
| 9 | ||
| 10 | The GNU C Library is distributed in the hope that it will be useful, | |
| 11 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
| 13 | Library General Public License for more details. | |
| 14 | ||
| 15 | You should have received a copy of the GNU Library General Public | |
| 16 | License along with the GNU C Library; see the file COPYING.LIB. If not, | |
| 17 | write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, | |
| 18 | Boston, MA 02111-1307, USA. */ | |
| 19 | ||
| 20 | #include <quad_float.h> | |
| 21 | ||
| 22 | /* long double _q_dtoq(double a); | |
| 23 | Convert 'a' to long double. Don't raise exceptions. | |
| 24 | */ | |
| 25 | ||
| 26 | void | |
| 27 | __q_dtoq(unsigned long long result[2], double a) | |
| 28 | { | |
| 29 | unsigned ux, rx; | |
| 30 | union { | |
| 31 | double d; | |
| 32 | unsigned long long u; | |
| 33 | } u; | |
| 34 | ||
| 35 | u.d = a; | |
| 36 | result[1] = u.u << 64-4; | |
| 37 | result[0] = u.u >> 4; | |
| 38 | /* correct exponent bias */ | |
| 39 | rx = ((long long)u.u >> 52 & 0x87ff) + 16383-1023; | |
| 40 | ||
| 41 | ux = u.u >> 52 & 0x7ff; | |
| 42 | if (ux == 0) | |
| 43 | { | |
| 44 | if ((u.u & 0x7fffffffffffffffULL) == 0) | |
| 45 | { | |
| 46 | /* +0.0 or -0.0. */ | |
| 47 | rx &= 0x8000; | |
| 48 | } | |
| 49 | else | |
| 50 | { | |
| 51 | /* Denormalised number. Renormalise. */ | |
| 52 | unsigned long long um = u.u & 0x000fffffffffffffULL; | |
| 53 | int cs = cntlzd(um) - 12 + 1; | |
| 54 | rx -= cs; | |
| 55 | um <<= cs; | |
| 56 | result[0] = um >> 4; | |
| 57 | result[1] = um << 64-4; | |
| 58 | } | |
| 59 | } | |
| 60 | else if (ux == 0x7ff) | |
| 61 | { | |
| 62 | /* Inf or NaN. */ | |
| 63 | rx |= 0x7fff; | |
| 64 | } | |
| 65 | *(unsigned short *)result = rx; | |
| 66 | } |