| |
| /* |
| * Copyright (c) 1998, 2001, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| /* |
| * rint(x) |
| * Return x rounded to integral value according to the prevailing |
| * rounding mode. |
| * Method: |
| * Using floating addition. |
| * Exception: |
| * Inexact flag raised if x not equal to rint(x). |
| */ |
| |
| #include "fdlibm.h" |
| |
| #ifdef __STDC__ |
| static const double |
| #else |
| static double |
| #endif |
| TWO52[2]={ |
| 4.50359962737049600000e+15, /* 0x43300000, 0x00000000 */ |
| -4.50359962737049600000e+15, /* 0xC3300000, 0x00000000 */ |
| }; |
| |
| #ifdef __STDC__ |
| double rint(double x) |
| #else |
| double rint(x) |
| double x; |
| #endif |
| { |
| int i0,j0,sx; |
| unsigned i,i1; |
| double w,t; |
| i0 = __HI(x); |
| sx = (i0>>31)&1; |
| i1 = __LO(x); |
| j0 = ((i0>>20)&0x7ff)-0x3ff; |
| if(j0<20) { |
| if(j0<0) { |
| if(((i0&0x7fffffff)|i1)==0) return x; |
| i1 |= (i0&0x0fffff); |
| i0 &= 0xfffe0000; |
| i0 |= ((i1|-i1)>>12)&0x80000; |
| __HI(x)=i0; |
| w = TWO52[sx]+x; |
| t = w-TWO52[sx]; |
| i0 = __HI(t); |
| __HI(t) = (i0&0x7fffffff)|(sx<<31); |
| return t; |
| } else { |
| i = (0x000fffff)>>j0; |
| if(((i0&i)|i1)==0) return x; /* x is integral */ |
| i>>=1; |
| if(((i0&i)|i1)!=0) { |
| if(j0==19) i1 = 0x40000000; else |
| i0 = (i0&(~i))|((0x20000)>>j0); |
| } |
| } |
| } else if (j0>51) { |
| if(j0==0x400) return x+x; /* inf or NaN */ |
| else return x; /* x is integral */ |
| } else { |
| i = ((unsigned)(0xffffffff))>>(j0-20); |
| if((i1&i)==0) return x; /* x is integral */ |
| i>>=1; |
| if((i1&i)!=0) i1 = (i1&(~i))|((0x40000000)>>(j0-20)); |
| } |
| __HI(x) = i0; |
| __LO(x) = i1; |
| w = TWO52[sx]+x; |
| return w-TWO52[sx]; |
| } |
