| /* |
| * 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. |
| */ |
| |
| /* |
| * double logb(x) |
| * IEEE 754 logb. Included to pass IEEE test suite. Not recommend. |
| * Use ilogb instead. |
| */ |
| |
| #include "fdlibm.h" |
| |
| #ifdef __STDC__ |
| double logb(double x) |
| #else |
| double logb(x) |
| double x; |
| #endif |
| { |
| int lx,ix; |
| ix = (__HI(x))&0x7fffffff; /* high |x| */ |
| lx = __LO(x); /* low x */ |
| if((ix|lx)==0) return -1.0/fabs(x); |
| if(ix>=0x7ff00000) return x*x; |
| if((ix>>=20)==0) /* IEEE 754 logb */ |
| return -1022.0; |
| else |
| return (double) (ix-1023); |
| } |
