2 * SPDX-License-Identifier: BSD-3-Clause
4 * Copyright (c) 1992, 1993
5 * The Regents of the University of California. All rights reserved.
7 * This software was developed by the Computer Systems Engineering group
8 * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
9 * contributed to Berkeley.
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 * 3. Neither the name of the University nor the names of its contributors
20 * may be used to endorse or promote products derived from this software
21 * without specific prior written permission.
23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36 #if defined(LIBC_SCCS) && !defined(lint)
37 static char sccsid[] = "@(#)fixunsdfdi.c 8.1 (Berkeley) 6/4/93";
38 #endif /* LIBC_SCCS and not lint */
39 #include <sys/cdefs.h>
40 __FBSDID("$FreeBSD$");
44 #define ONE_FOURTH (1 << (LONG_BITS - 2))
45 #define ONE_HALF (ONE_FOURTH * 2.0)
46 #define ONE (ONE_FOURTH * 4.0)
49 * Convert double to (unsigned) quad.
50 * Not sure what to do with negative numbers---for now, anything out
51 * of range becomes UQUAD_MAX.
54 __fixunsdfdi(double x)
60 return (UQUAD_MAX); /* ??? should be 0? ERANGE??? */
61 #ifdef notdef /* this falls afoul of a GCC bug */
64 #else /* so we wire in 2^64-1 instead */
65 if (x >= 18446744073709551615.0)
69 * Get the upper part of the result. Note that the divide
70 * may round up; we want to avoid this if possible, so we
71 * subtract `1/2' first.
73 toppart = (x - ONE_HALF) / ONE;
75 * Now build a u_quad_t out of the top part. The difference
76 * between x and this is the bottom part (this may introduce
77 * a few fuzzy bits, but what the heck). With any luck this
78 * difference will be nonnegative: x should wind up in the
79 * range [0..ULONG_MAX]. For paranoia, we assume [LONG_MIN..
80 * 2*ULONG_MAX] instead.
82 t.ul[H] = (unsigned long)toppart;