xref: /freebsd/lib/libc/quad/quad.h (revision dd41de95a84d979615a2ef11df6850622bf6184e)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
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. Neither the name of the University nor the names of its contributors
20  *    may be used to endorse or promote products derived from this software
21  *    without specific prior written permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33  * SUCH DAMAGE.
34  *
35  *	@(#)quad.h	8.1 (Berkeley) 6/4/93
36  * $FreeBSD$
37  */
38 
39 /*
40  * Quad arithmetic.
41  *
42  * This library makes the following assumptions:
43  *
44  *  - The type long long (aka quad_t) exists.
45  *
46  *  - A quad variable is exactly twice as long as `long'.
47  *
48  *  - The machine's arithmetic is two's complement.
49  *
50  * This library can provide 128-bit arithmetic on a machine with 128-bit
51  * quads and 64-bit longs, for instance, or 96-bit arithmetic on machines
52  * with 48-bit longs.
53  */
54 
55 #include <sys/types.h>
56 #include <limits.h>
57 
58 /*
59  * Depending on the desired operation, we view a `long long' (aka quad_t) in
60  * one or more of the following formats.
61  */
62 union uu {
63 	quad_t	q;		/* as a (signed) quad */
64 	quad_t	uq;		/* as an unsigned quad */
65 	long	sl[2];		/* as two signed longs */
66 	u_long	ul[2];		/* as two unsigned longs */
67 };
68 
69 /*
70  * Define high and low longwords.
71  */
72 #define	H		_QUAD_HIGHWORD
73 #define	L		_QUAD_LOWWORD
74 
75 /*
76  * Total number of bits in a quad_t and in the pieces that make it up.
77  * These are used for shifting, and also below for halfword extraction
78  * and assembly.
79  */
80 #define	QUAD_BITS	(sizeof(quad_t) * CHAR_BIT)
81 #define	LONG_BITS	(sizeof(long) * CHAR_BIT)
82 #define	HALF_BITS	(sizeof(long) * CHAR_BIT / 2)
83 
84 /*
85  * Extract high and low shortwords from longword, and move low shortword of
86  * longword to upper half of long, i.e., produce the upper longword of
87  * ((quad_t)(x) << (number_of_bits_in_long/2)).  (`x' must actually be u_long.)
88  *
89  * These are used in the multiply code, to split a longword into upper
90  * and lower halves, and to reassemble a product as a quad_t, shifted left
91  * (sizeof(long)*CHAR_BIT/2).
92  */
93 #define	HHALF(x)	((x) >> HALF_BITS)
94 #define	LHALF(x)	((x) & ((1L << HALF_BITS) - 1))
95 #define	LHUP(x)		((x) << HALF_BITS)
96 
97 int		__cmpdi2(quad_t a, quad_t b);
98 quad_t		__divdi3(quad_t a, quad_t b);
99 quad_t		__moddi3(quad_t a, quad_t b);
100 u_quad_t	__qdivrem(u_quad_t u, u_quad_t v, u_quad_t *rem);
101 int		__ucmpdi2(u_quad_t a, u_quad_t b);
102 u_quad_t	__udivdi3(u_quad_t a, u_quad_t b);
103 u_quad_t	__umoddi3(u_quad_t a, u_quad_t b);
104 
105 typedef unsigned int	qshift_t;
106