quad.h revision 92741 
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 92741 2002-03-20 02:15:46Z alfred $
39 */
40
41/*
42 * Quad arithmetic.
43 *
44 * This library makes the following assumptions:
45 *
46 *  - The type long long (aka quad_t) exists.
47 *
48 *  - A quad variable is exactly twice as long as `long'.
49 *
50 *  - The machine's arithmetic is two's complement.
51 *
52 * This library can provide 128-bit arithmetic on a machine with 128-bit
53 * quads and 64-bit longs, for instance, or 96-bit arithmetic on machines
54 * with 48-bit longs.
55 */
56
57#include <sys/cdefs.h>
58#include <sys/types.h>
59#include <sys/syslimits.h>
60#include <machine/limits.h>
61
62/*
63 * Depending on the desired operation, we view a `long long' (aka quad_t) in
64 * one or more of the following formats.
65 */
66union uu {
67	quad_t	q;		/* as a (signed) quad */
68	quad_t	uq;		/* as an unsigned quad */
69	long	sl[2];		/* as two signed longs */
70	u_long	ul[2];		/* as two unsigned longs */
71};
72
73/*
74 * Define high and low longwords.
75 */
76#define	H		_QUAD_HIGHWORD
77#define	L		_QUAD_LOWWORD
78
79/*
80 * Total number of bits in a quad_t and in the pieces that make it up.
81 * These are used for shifting, and also below for halfword extraction
82 * and assembly.
83 */
84#define	QUAD_BITS	(sizeof(quad_t) * CHAR_BIT)
85#define	LONG_BITS	(sizeof(long) * CHAR_BIT)
86#define	HALF_BITS	(sizeof(long) * CHAR_BIT / 2)
87
88/*
89 * Extract high and low shortwords from longword, and move low shortword of
90 * longword to upper half of long, i.e., produce the upper longword of
91 * ((quad_t)(x) << (number_of_bits_in_long/2)).  (`x' must actually be u_long.)
92 *
93 * These are used in the multiply code, to split a longword into upper
94 * and lower halves, and to reassemble a product as a quad_t, shifted left
95 * (sizeof(long)*CHAR_BIT/2).
96 */
97#define	HHALF(x)	((x) >> HALF_BITS)
98#define	LHALF(x)	((x) & ((1 << HALF_BITS) - 1))
99#define	LHUP(x)		((x) << HALF_BITS)
100
101quad_t		__divdi3(quad_t a, quad_t b);
102quad_t		__moddi3(quad_t a, quad_t b);
103u_quad_t	__qdivrem(u_quad_t u, u_quad_t v, u_quad_t *rem);
104u_quad_t	__udivdi3(u_quad_t a, u_quad_t b);
105u_quad_t	__umoddi3(u_quad_t a, u_quad_t b);
106int		__ucmpdi2(u_quad_t a, u_quad_t b);
107
108/*
109 * XXX
110 * Compensate for gcc 1 vs gcc 2.  Gcc 1 defines ?sh?di3's second argument
111 * as u_quad_t, while gcc 2 correctly uses int.  Unfortunately, we still use
112 * both compilers.
113 */
114#if __GNUC__ >= 2
115typedef unsigned int	qshift_t;
116#else
117typedef u_quad_t	qshift_t;
118#endif
119