1 /*- 2 * Copyright (c) 2004-2005 David Schultz <das (at) FreeBSD.ORG> 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 * 26 * $FreeBSD$ 27 */ 28 29 #include <float.h> 30 #include <math.h> 31 32 #include "fpmath.h" 33 34 #if LDBL_MAX_EXP != 0x4000 35 #error "Unsupported long double format" 36 #endif 37 38 long double 39 frexpl(long double x, int *ex) 40 { 41 union IEEEl2bits u; 42 43 u.e = x; 44 switch (u.bits.exp) { 45 case 0: /* 0 or subnormal */ 46 if ((u.bits.manl | u.bits.manh) == 0) { 47 *ex = 0; 48 } else { 49 u.e *= 0x1.0p514; 50 *ex = u.bits.exp - 0x4200; 51 u.bits.exp = 0x3ffe; 52 } 53 break; 54 case 0x7fff: /* infinity or NaN; value of *ex is unspecified */ 55 break; 56 default: /* normal */ 57 *ex = u.bits.exp - 0x3ffe; 58 u.bits.exp = 0x3ffe; 59 break; 60 } 61 return (u.e); 62 } 63
