quad.h revision 330897 
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 * 4. 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: stable/11/lib/libc/quad/quad.h 330897 2018-03-14 03:19:51Z eadler $
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 */
62union 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) & ((1 << HALF_BITS) - 1))
95#define	LHUP(x)		((x) << HALF_BITS)
96
97int		__cmpdi2(quad_t a, quad_t b);
98quad_t		__divdi3(quad_t a, quad_t b);
99quad_t		__moddi3(quad_t a, quad_t b);
100u_quad_t	__qdivrem(u_quad_t u, u_quad_t v, u_quad_t *rem);
101int		__ucmpdi2(u_quad_t a, u_quad_t b);
102u_quad_t	__udivdi3(u_quad_t a, u_quad_t b);
103u_quad_t	__umoddi3(u_quad_t a, u_quad_t b);
104
105typedef unsigned int	qshift_t;
106