2 * Copyright (c) 2008 David Schultz <das@FreeBSD.ORG>
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
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.
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
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
35 #define BIAS (LDBL_MAX_EXP - 1)
39 #if LDBL_MANT_DIG == 64
41 #elif LDBL_MANT_DIG == 113
44 #error "Unsupported long double format"
56 if (u.bits.exp >= BIAS + LDBL_MANT_DIG - 1) {
58 * The biased exponent is greater than the number of digits
59 * in the mantissa, so x is inf, NaN, or an integer.
66 * The following code assumes that intermediate results are
67 * evaluated in long double precision. If they are evaluated in
68 * greater precision, double rounding may occur, and if they are
69 * evaluated in less precision (as on i386), results will be
76 * If the result is +-0, then it must have the same sign as x, but
77 * the above calculation doesn't always give this. Fix up the sign.
80 return (sign ? -0.0L : 0.0L);