| /* |
| * 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. |
| */ |
| |
| /* |
| * for non-zero x |
| * x = frexp(arg,&exp); |
| * return a double fp quantity x such that 0.5 <= |x| <1.0 |
| * and the corresponding binary exponent "exp". That is |
| * arg = x*2^exp. |
| * If arg is inf, 0.0, or NaN, then frexp(arg,&exp) returns arg |
| * with *exp=0. |
| */ |
| |
| #include "fdlibm.h" |
| |
| #ifdef __STDC__ |
| static const double |
| #else |
| static double |
| #endif |
| two54 = 1.80143985094819840000e+16; /* 0x43500000, 0x00000000 */ |
| |
| #ifdef __STDC__ |
| double frexp(double x, int *eptr) |
| #else |
| double frexp(x, eptr) |
| double x; int *eptr; |
| #endif |
| { |
| int hx, ix, lx; |
| hx = __HI(x); |
| ix = 0x7fffffff&hx; |
| lx = __LO(x); |
| *eptr = 0; |
| if(ix>=0x7ff00000||((ix|lx)==0)) return x; /* 0,inf,nan */ |
| if (ix<0x00100000) { /* subnormal */ |
| x *= two54; |
| hx = __HI(x); |
| ix = hx&0x7fffffff; |
| *eptr = -54; |
| } |
| *eptr += (ix>>20)-1022; |
| hx = (hx&0x800fffff)|0x3fe00000; |
| __HI(x) = hx; |
| return x; |
| } |