1 /***********************************************************************
2 *                                                                      *
3 *               This software is part of the ast package               *
4 *          Copyright (c) 1985-2011 AT&T Intellectual Property          *
5 *                      and is licensed under the                       *
6 *                 Eclipse Public License, Version 1.0                  *
7 *                    by AT&T Intellectual Property                     *
8 *                                                                      *
9 *                A copy of the License is available at                 *
10 *          http://www.eclipse.org/org/documents/epl-v10.html           *
11 *         (with md5 checksum b35adb5213ca9657e911e9befb180842)         *
12 *                                                                      *
13 *              Information and Software Systems Research               *
14 *                            AT&T Research                             *
15 *                           Florham Park NJ                            *
16 *                                                                      *
17 *                 Glenn Fowler <gsf@research.att.com>                  *
18 *                  David Korn <dgk@research.att.com>                   *
19 *                   Phong Vo <kpv@research.att.com>                    *
20 *                                                                      *
21 ***********************************************************************/
22 #pragma prototyped
23 /*
24  * K. P. Vo
25  * G. S. Fowler
26  * AT&T Research
27  *
28  * ``the best'' combined linear congruent checksum/hash/PRNG
29  */
30 
31 #ifndef _HASHPART_H
32 #define _HASHPART_H
33 
34 #define HASH_ADD(h)	(0x9c39c33dL)
35 
36 #if __sparc__ || __sparc || sparc
37 
38 #define HASH_A(h,n)	((((h) << 2) - (h)) << (n))
39 #define HASH_B(h,n)	((((h) << 4) - (h)) << (n))
40 #define HASH_C(h,n)	((HASH_A(h,7) + HASH_B(h,0)) << (n))
41 #define HASH_MPY(h)	(HASH_C(h,22)+HASH_C(h,10)+HASH_A(h,6)+HASH_A(h,3)+(h))
42 
43 #else
44 
45 #define HASH_MPY(h)	((h)*0x63c63cd9L)
46 
47 #endif
48 
49 #define HASHPART(h,c)	(h = HASH_MPY(h) + HASH_ADD(h) + (c))
50 
51 #endif
52