BSD 4_4 release
[unix-history] / usr / src / sys / libkern / lshrdi3.c
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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 *
c0567266
KB
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.
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36 */
37
38#if defined(LIBC_SCCS) && !defined(lint)
39static char sccsid[] = "@(#)lshrdi3.c 8.1 (Berkeley) 6/4/93";
40#endif /* LIBC_SCCS and not lint */
41
42#include "quad.h"
43
44/*
45 * Shift an (unsigned) quad value right (logical shift right).
46 */
47quad_t
48__lshrdi3(a, shift)
49 quad_t a;
50 qshift_t shift;
51{
52 union uu aa;
53
54 aa.q = a;
55 if (shift >= LONG_BITS) {
56 aa.ul[L] = shift >= QUAD_BITS ? 0 :
57 aa.ul[H] >> (shift - LONG_BITS);
58 aa.ul[H] = 0;
59 } else if (shift > 0) {
60 aa.ul[L] = (aa.ul[L] >> shift) |
61 (aa.ul[H] << (LONG_BITS - shift));
62 aa.ul[H] >>= shift;
63 }
64 return (aa.q);
65}