quad.h revision 1541 
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 */
39
40/*
41 * Quad arithmetic.
42 *
43 * This library makes the following assumptions:
44 *
45 *  - The type long long (aka quad_t) exists.
46 *
47 *  - A quad variable is exactly twice as long as `long'.
48 *
49 *  - The machine's arithmetic is two's complement.
50 *
51 * This library can provide 128-bit arithmetic on a machine with 128-bit
52 * quads and 64-bit longs, for instance, or 96-bit arithmetic on machines
53 * with 48-bit longs.
54 */
55
56#include <sys/types.h>
57#include <limits.h>
58
59/*
60 * Depending on the desired operation, we view a `long long' (aka quad_t) in
61 * one or more of the following formats.
62 */
63union uu {
64	quad_t	q;		/* as a (signed) quad */
65	quad_t	uq;		/* as an unsigned quad */
66	long	sl[2];		/* as two signed longs */
67	u_long	ul[2];		/* as two unsigned longs */
68};
69
70/*
71 * Define high and low longwords.
72 */
73#define	H		_QUAD_HIGHWORD
74#define	L		_QUAD_LOWWORD
75
76/*
77 * Total number of bits in a quad_t and in the pieces that make it up.
78 * These are used for shifting, and also below for halfword extraction
79 * and assembly.
80 */
81#define	QUAD_BITS	(sizeof(quad_t) * CHAR_BIT)
82#define	LONG_BITS	(sizeof(long) * CHAR_BIT)
83#define	HALF_BITS	(sizeof(long) * CHAR_BIT / 2)
84
85/*
86 * Extract high and low shortwords from longword, and move low shortword of
87 * longword to upper half of long, i.e., produce the upper longword of
88 * ((quad_t)(x) << (number_of_bits_in_long/2)).  (`x' must actually be u_long.)
89 *
90 * These are used in the multiply code, to split a longword into upper
91 * and lower halves, and to reassemble a product as a quad_t, shifted left
92 * (sizeof(long)*CHAR_BIT/2).
93 */
94#define	HHALF(x)	((x) >> HALF_BITS)
95#define	LHALF(x)	((x) & ((1 << HALF_BITS) - 1))
96#define	LHUP(x)		((x) << HALF_BITS)
97
98extern u_quad_t __qdivrem __P((u_quad_t u, u_quad_t v, u_quad_t *rem));
99
100/*
101 * XXX
102 * Compensate for gcc 1 vs gcc 2.  Gcc 1 defines ?sh?di3's second argument
103 * as u_quad_t, while gcc 2 correctly uses int.  Unfortunately, we still use
104 * both compilers.
105 */
106#if __GNUC__ >= 2
107typedef unsigned int	qshift_t;
108#else
109typedef u_quad_t	qshift_t;
110#endif
111