Rev 2 | Details | Compare with Previous | Last modification | View Log | RSS feed
Rev | Author | Line No. | Line |
---|---|---|---|
2 | pj | 1 | /*- |
2 | * Copyright (c) 1992, 1993 |
||
3 | * The Regents of the University of California. All rights reserved. |
||
4 | * |
||
5 | * This software was developed by the Computer Systems Engineering group |
||
6 | * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and |
||
7 | * contributed to Berkeley. |
||
8 | * |
||
9 | * Redistribution and use in source and binary forms, with or without |
||
10 | * modification, are permitted provided that the following conditions |
||
11 | * are met: |
||
12 | * 1. Redistributions of source code must retain the above copyright |
||
13 | * notice, this list of conditions and the following disclaimer. |
||
14 | * 2. Redistributions in binary form must reproduce the above copyright |
||
15 | * notice, this list of conditions and the following disclaimer in the |
||
16 | * documentation and/or other materials provided with the distribution. |
||
17 | * 3. All advertising materials mentioning features or use of this software |
||
18 | * must display the following acknowledgement: |
||
19 | * This product includes software developed by the University of |
||
20 | * California, Berkeley and its contributors. |
||
21 | * 4. Neither the name of the University nor the names of its contributors |
||
22 | * may be used to endorse or promote products derived from this software |
||
23 | * without specific prior written permission. |
||
24 | * |
||
25 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
||
26 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
||
27 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
||
28 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
||
29 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
||
30 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
||
31 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
||
32 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
||
33 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
||
34 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
||
35 | * SUCH DAMAGE. |
||
36 | */ |
||
37 | |||
38 | #if defined(LIBC_SCCS) && !defined(lint) |
||
39 | static char sccsid[] = "@(#)fixunsdfdi.c 8.1 (Berkeley) 6/4/93"; |
||
40 | #endif /* LIBC_SCCS and not lint */ |
||
41 | |||
42 | #include "quad.h" |
||
43 | |||
44 | #define ONE_FOURTH (1 << (LONG_BITS - 2)) |
||
45 | #define ONE_HALF (ONE_FOURTH * 2.0) |
||
46 | #define ONE (ONE_FOURTH * 4.0) |
||
47 | |||
48 | /* |
||
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. |
||
52 | */ |
||
53 | u_quad_t |
||
54 | __fixunsdfdi(x) |
||
55 | double x; |
||
56 | { |
||
57 | double toppart; |
||
58 | union uu t; |
||
59 | |||
60 | if (x < 0) |
||
61 | return (UQUAD_MAX); /* ??? should be 0? ERANGE??? */ |
||
62 | #ifdef notdef /* this falls afoul of a GCC bug */ |
||
63 | if (x >= UQUAD_MAX) |
||
64 | return (UQUAD_MAX); |
||
65 | #else /* so we wire in 2^64-1 instead */ |
||
66 | if (x >= 18446744073709551615.0) |
||
67 | return (UQUAD_MAX); |
||
68 | #endif |
||
69 | /* |
||
70 | * Get the upper part of the result. Note that the divide |
||
71 | * may round up; we want to avoid this if possible, so we |
||
72 | * subtract `1/2' first. |
||
73 | */ |
||
74 | toppart = (x - ONE_HALF) / ONE; |
||
75 | /* |
||
76 | * Now build a u_quad_t out of the top part. The difference |
||
77 | * between x and this is the bottom part (this may introduce |
||
78 | * a few fuzzy bits, but what the heck). With any luck this |
||
79 | * difference will be nonnegative: x should wind up in the |
||
80 | * range [0..ULONG_MAX]. For paranoia, we assume [LONG_MIN.. |
||
81 | * 2*ULONG_MAX] instead. |
||
82 | */ |
||
83 | t.ul[H] = (unsigned long)toppart; |
||
84 | t.ul[L] = 0; |
||
85 | x -= (double)t.uq; |
||
86 | if (x < 0) { |
||
87 | t.ul[H]--; |
||
88 | x += ULONG_MAX; |
||
89 | } |
||
90 | if (x > ULONG_MAX) { |
||
91 | t.ul[H]++; |
||
92 | x -= ULONG_MAX; |
||
93 | } |
||
94 | t.ul[L] = (u_long)x; |
||
95 | return (t.uq); |
||
96 | } |