projects / thirdparty / glibc.git / blame
| Commit | Line | Data |
|---|---|---|
| d4a28569 UD |
1 | /* Round double to integer away from zero. |
| 2 | Copyright (C) 2011 Free Software Foundation, Inc. | |
| 3 | This file is part of the GNU C Library. | |
| 4 | Contributed by Ulrich Drepper <drepper@cygnus.com>, 2011. | |
| 5 | ||
| 6 | The GNU C Library is free software; you can redistribute it and/or | |
| 7 | modify it under the terms of the GNU Lesser General Public | |
| 8 | License as published by the Free Software Foundation; either | |
| 9 | version 2.1 of the License, or (at your option) any later version. | |
| 10 | ||
| 11 | The GNU C Library is distributed in the hope that it will be useful, | |
| 12 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
| 14 | Lesser General Public License for more details. | |
| 15 | ||
| 16 | You should have received a copy of the GNU Lesser General Public | |
| 17 | License along with the GNU C Library; if not, write to the Free | |
| 18 | Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA | |
| 19 | 02111-1307 USA. */ | |
| 20 | ||
| 21 | /* Based on a version which carries the following copyright: */ | |
| 22 | ||
| 23 | /* | |
| 24 | * ==================================================== | |
| 25 | * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. | |
| 26 | * | |
| 27 | * Developed at SunPro, a Sun Microsystems, Inc. business. | |
| 28 | * Permission to use, copy, modify, and distribute this | |
| 29 | * software is freely granted, provided that this notice | |
| 30 | * is preserved. | |
| 31 | * ==================================================== | |
| 32 | */ | |
| 33 | ||
| 34 | #include "math.h" | |
| 35 | #include "math_private.h" | |
| 36 | ||
| 37 | /* | |
| 38 | * floor(x) | |
| 39 | * Return x rounded toward -inf to integral value | |
| 40 | * Method: | |
| 41 | * Bit twiddling. | |
| 42 | * Exception: | |
| 43 | * Inexact flag raised if x not equal to floor(x). | |
| 44 | */ | |
| 45 | ||
| 46 | static const double huge = 1.0e300; | |
| 47 | ||
| 48 | ||
| 49 | double | |
| 50 | __floor (double x) | |
| 51 | { | |
| 52 | int64_t i0; | |
| 53 | EXTRACT_WORDS64(i0,x); | |
| 54 | int32_t j0 = ((i0>>52)&0x7ff)-0x3ff; | |
| 55 | if(__builtin_expect(j0<52, 1)) { | |
| 56 | if(j0<0) { /* raise inexact if x != 0 */ | |
| 57 | if(huge+x>0.0) {/* return 0*sign(x) if |x|<1 */ | |
| 58 | if(i0>=0) {i0=0;} | |
| 59 | else if((i0&0x7fffffffffffffffl)!=0) | |
| 60 | { i0=0xbff0000000000000l;} | |
| 61 | } | |
| 62 | } else { | |
| 63 | uint64_t i = (0x000fffffffffffffl)>>j0; | |
| 64 | if((i0&i)==0) return x; /* x is integral */ | |
| 65 | if(huge+x>0.0) { /* raise inexact flag */ | |
| 66 | if(i0<0) i0 += (0x0010000000000000l)>>j0; | |
| 67 | i0 &= (~i); | |
| 68 | } | |
| 69 | } | |
| 70 | INSERT_WORDS64(x,i0); | |
| 71 | } else if (j0==0x400) | |
| 72 | return x+x; /* inf or NaN */ | |
| 73 | return x; | |
| 74 | } | |
| 75 | weak_alias (__floor, floor) | |
| 76 | #ifdef NO_LONG_DOUBLE | |
| 77 | strong_alias (__floor, __floorl) | |
| 78 | weak_alias (__floor, floorl) | |
| 79 | #endif |