1 /* $NetBSD: mi_vector_hash.c,v 1.1 2009/07/20 17:03:37 joerg Exp $ */
3 * Copyright (c) 2009 The NetBSD Foundation, Inc.
6 * This code is derived from software contributed to The NetBSD Foundation
7 * by Joerg Sonnenberger.
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in
17 * the documentation and/or other materials provided with the
20 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
23 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
24 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
25 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
26 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
27 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
28 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
29 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
30 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 #include <sys/cdefs.h>
35 __RCSID("$NetBSD: mi_vector_hash.c,v 1.1 2009/07/20 17:03:37 joerg Exp $");
39 #if ULONGLONG_MAX > 0xffffffffffffffffULL
40 #error "Unsupported architecture"
44 * If unsigned long long is larger than size_t, the follow assumes that
45 * splitting into 32bit halfes is faster.
47 * The native pocountll version is based on the same ideas as popcount(3),
48 * see popcount.c for comments.
51 #if ULONGLONG_MAX > SIZE_MAX
53 popcountll(unsigned long long v
)
55 return popcount(v
>> 32) + popcount(v
& 0xffffffffU
);
59 popcountll(unsigned long long v
)
63 v
= v
- ((v
>> 1) & 0x5555555555555555ULL
);
64 v
= (v
& 0x3333333333333333ULL
) + ((v
>> 2) & 0x3333333333333333ULL
);
65 v
= ((v
+ (v
>> 4)) & 0x0f0f0f0f0f0f0f0fULL
) * 0x0101010101010101ULL
;