quad.h revision 1.2 
1/*	$NetBSD: quad.h,v 1.5 1995/10/12 15:13:58 jtc Exp $	*/
2
3/*-
4 * Copyright (c) 1992, 1993
5 *	The Regents of the University of California.  All rights reserved.
6 *
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.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
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. All advertising materials mentioning features or use of this software
20 *    must display the following acknowledgement:
21 *	This product includes software developed by the University of
22 *	California, Berkeley and its contributors.
23 * 4. Neither the name of the University nor the names of its contributors
24 *    may be used to endorse or promote products derived from this software
25 *    without specific prior written permission.
26 *
27 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
28 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
29 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
30 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
31 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
32 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
33 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
34 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
35 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
36 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
37 * SUCH DAMAGE.
38 *
39 *	@(#)quad.h	8.1 (Berkeley) 6/4/93
40 */
41
42/*
43 * Quad arithmetic.
44 *
45 * This library makes the following assumptions:
46 *
47 *  - The type long long (aka quad_t) exists.
48 *
49 *  - A quad variable is exactly twice as long as `long'.
50 *
51 *  - The machine's arithmetic is two's complement.
52 *
53 * This library can provide 128-bit arithmetic on a machine with 128-bit
54 * quads and 64-bit longs, for instance, or 96-bit arithmetic on machines
55 * with 48-bit longs.
56 */
57
58#include <sys/types.h>
59#include <limits.h>
60
61/*
62 * Depending on the desired operation, we view a `long long' (aka quad_t) in
63 * one or more of the following formats.
64 */
65union uu {
66	quad_t	q;		/* as a (signed) quad */
67	u_quad_t uq;		/* as an unsigned quad */
68	long	sl[2];		/* as two signed longs */
69	u_long	ul[2];		/* as two unsigned longs */
70};
71
72/*
73 * Define high and low longwords.
74 */
75#define	H		_QUAD_HIGHWORD
76#define	L		_QUAD_LOWWORD
77
78/*
79 * Total number of bits in a quad_t and in the pieces that make it up.
80 * These are used for shifting, and also below for halfword extraction
81 * and assembly.
82 */
83#define	QUAD_BITS	(sizeof(quad_t) * CHAR_BIT)
84#define	LONG_BITS	(sizeof(long) * CHAR_BIT)
85#define	HALF_BITS	(sizeof(long) * CHAR_BIT / 2)
86
87/*
88 * Extract high and low shortwords from longword, and move low shortword of
89 * longword to upper half of long, i.e., produce the upper longword of
90 * ((quad_t)(x) << (number_of_bits_in_long/2)).  (`x' must actually be u_long.)
91 *
92 * These are used in the multiply code, to split a longword into upper
93 * and lower halves, and to reassemble a product as a quad_t, shifted left
94 * (sizeof(long)*CHAR_BIT/2).
95 */
96#define	HHALF(x)	((u_long)(x) >> HALF_BITS)
97#define	LHALF(x)	((u_long)(x) & (((long)1 << HALF_BITS) - 1))
98#define	LHUP(x)		((u_long)(x) << HALF_BITS)
99
100extern u_quad_t __qdivrem __P((u_quad_t u, u_quad_t v, u_quad_t *rem));
101
102/*
103 * XXX
104 * Compensate for gcc 1 vs gcc 2.  Gcc 1 defines ?sh?di3's second argument
105 * as u_quad_t, while gcc 2 correctly uses int.  Unfortunately, we still use
106 * both compilers.
107 */
108#if __GNUC__ >= 2
109typedef unsigned int	qshift_t;
110#else
111typedef u_quad_t	qshift_t;
112#endif
113