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source: vbox/trunk/src/VBox/Runtime/common/math/gcc/ashrdi3.c@ 44336

最後變更 在這個檔案從44336是 830,由 vboxsync 提交於 18 年 前

Made it built (but currently disabled).

  • 屬性 svn:eol-style 設為 native
檔案大小: 2.9 KB
 
1/* $NetBSD: ashrdi3.c,v 1.10 2005/12/11 12:24:37 christos Exp $ */
2
3/*-
4 * Copyright (c) 1992, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
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.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
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.
22 *
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
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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
33 * SUCH DAMAGE.
34 */
35
36/*#include <sys/cdefs.h>
37#if defined(LIBC_SCCS) && !defined(lint)
38#if 0
39static char sccsid[] = "@(#)ashrdi3.c 8.1 (Berkeley) 6/4/93";
40#else
41__RCSID("$NetBSD: ashrdi3.c,v 1.10 2005/12/11 12:24:37 christos Exp $");
42#endif
43#endif*/ /* LIBC_SCCS and not lint */
44
45#include "quad.h"
46
47/*
48 * Shift a (signed) quad value right (arithmetic shift right).
49 */
50quad_t
51__ashrdi3(a, shift)
52 quad_t a;
53 qshift_t shift;
54{
55 union uu aa;
56
57 if (shift == 0)
58 return(a);
59 aa.q = a;
60 if (shift >= INT_BITS) {
61 int s;
62
63 /*
64 * Smear bits rightward using the machine's right-shift
65 * method, whether that is sign extension or zero fill,
66 * to get the `sign word' s. Note that shifting by
67 * INT_BITS is undefined, so we shift (INT_BITS-1),
68 * then 1 more, to get our answer.
69 */
70 /* LINTED inherits machine dependency */
71 s = (aa.sl[H] >> (INT_BITS - 1)) >> 1;
72 /* LINTED inherits machine dependency*/
73 aa.ul[L] = aa.sl[H] >> (shift - INT_BITS);
74 aa.ul[H] = s;
75 } else {
76 aa.ul[L] = (aa.ul[L] >> shift) |
77 (aa.ul[H] << (INT_BITS - shift));
78 /* LINTED inherits machine dependency */
79 aa.sl[H] >>= shift;
80 }
81 return (aa.q);
82}
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