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
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36 #include <sys/cdefs.h>
37 __FBSDID("$FreeBSD$");
39 #include <libkern/quad.h>
42 * Shift a (signed) quad value right (arithmetic shift right).
45 __ashrdi3(quad_t a, qshift_t shift)
50 if (shift >= LONG_BITS) {
54 * Smear bits rightward using the machine's right-shift
55 * method, whether that is sign extension or zero fill,
56 * to get the `sign word' s. Note that shifting by
57 * LONG_BITS is undefined, so we shift (LONG_BITS-1),
58 * then 1 more, to get our answer.
60 s = (aa.sl[H] >> (LONG_BITS - 1)) >> 1;
61 aa.ul[L] = shift >= QUAD_BITS ? s :
62 aa.sl[H] >> (shift - LONG_BITS);
64 } else if (shift > 0) {
65 aa.ul[L] = (aa.ul[L] >> shift) |
66 (aa.ul[H] << (LONG_BITS - shift));