quad.h revision 126891 
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 *
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.
36 *
37 *	@(#)quad.h	8.1 (Berkeley) 6/4/93
38 * $FreeBSD: head/sys/libkern/quad.h 126891 2004-03-12 21:45:33Z trhodes $
39 */
40
41#ifndef _LIBKERN_QUAD_H
42#define _LIBKERN_QUAD_H
43
44/*
45 * Quad arithmetic.
46 *
47 * This library makes the following assumptions:
48 *
49 *  - The type long long (aka quad_t) exists.
50 *
51 *  - A quad variable is exactly twice as long as `long'.
52 *
53 *  - The machine's arithmetic is two's complement.
54 *
55 * This library can provide 128-bit arithmetic on a machine with 128-bit
56 * quads and 64-bit longs, for instance, or 96-bit arithmetic on machines
57 * with 48-bit longs.
58 */
59
60#include <sys/cdefs.h>
61#include <sys/types.h>
62#include <sys/limits.h>
63#include <sys/syslimits.h>
64
65/*
66 * Depending on the desired operation, we view a `long long' (aka quad_t) in
67 * one or more of the following formats.
68 */
69union uu {
70	quad_t	q;		/* as a (signed) quad */
71	quad_t	uq;		/* as an unsigned quad */
72	long	sl[2];		/* as two signed longs */
73	u_long	ul[2];		/* as two unsigned longs */
74};
75
76/*
77 * Define high and low longwords.
78 */
79#define	H		_QUAD_HIGHWORD
80#define	L		_QUAD_LOWWORD
81
82/*
83 * Total number of bits in a quad_t and in the pieces that make it up.
84 * These are used for shifting, and also below for halfword extraction
85 * and assembly.
86 */
87#define	QUAD_BITS	(sizeof(quad_t) * CHAR_BIT)
88#define	LONG_BITS	(sizeof(long) * CHAR_BIT)
89#define	HALF_BITS	(sizeof(long) * CHAR_BIT / 2)
90
91/*
92 * Extract high and low shortwords from longword, and move low shortword of
93 * longword to upper half of long, i.e., produce the upper longword of
94 * ((quad_t)(x) << (number_of_bits_in_long/2)).  (`x' must actually be u_long.)
95 *
96 * These are used in the multiply code, to split a longword into upper
97 * and lower halves, and to reassemble a product as a quad_t, shifted left
98 * (sizeof(long)*CHAR_BIT/2).
99 */
100#define	HHALF(x)	((x) >> HALF_BITS)
101#define	LHALF(x)	((x) & ((1 << HALF_BITS) - 1))
102#define	LHUP(x)		((x) << HALF_BITS)
103
104quad_t		__divdi3(quad_t a, quad_t b);
105quad_t		__moddi3(quad_t a, quad_t b);
106u_quad_t	__qdivrem(u_quad_t u, u_quad_t v, u_quad_t *rem);
107u_quad_t	__udivdi3(u_quad_t a, u_quad_t b);
108u_quad_t	__umoddi3(u_quad_t a, u_quad_t b);
109int		__ucmpdi2(u_quad_t a, u_quad_t b);
110
111typedef unsigned int	qshift_t;
112#endif /* _LIBKERN_QUAD_H */
113