xref: /titanic_51/usr/src/boot/lib/libstand/quad.h (revision d828baa435f064b9a001576f57c5f19a0a32755c)
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  * 4. Neither the name of the University nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  *
33  *	@(#)quad.h	8.1 (Berkeley) 6/4/93
34  * $FreeBSD$
35  */
36 
37 /*
38  * Quad arithmetic.
39  *
40  * This library makes the following assumptions:
41  *
42  *  - The type long long (aka quad_t) exists.
43  *
44  *  - A quad variable is exactly twice as long as `long'.
45  *
46  *  - The machine's arithmetic is two's complement.
47  *
48  * This library can provide 128-bit arithmetic on a machine with 128-bit
49  * quads and 64-bit longs, for instance, or 96-bit arithmetic on machines
50  * with 48-bit longs.
51  */
52 
53 #include <sys/cdefs.h>
54 #include <sys/types.h>
55 #include <limits.h>
56 
57 _Static_assert(sizeof(quad_t) == sizeof(int) * 2,
58 	"Bitwise function in libstand are broken on this architecture\n");
59 
60 /*
61  * Depending on the desired operation, we view a `long long' (aka quad_t) in
62  * one or more of the following formats.
63  */
64 union uu {
65 	quad_t	q;		/* as a (signed) quad */
66 	quad_t	uq;		/* as an unsigned quad */
67 	int	sl[2];		/* as two signed ints */
68 	u_int	ul[2];		/* as two unsigned ints */
69 };
70 
71 /*
72  * Define high and low longwords.
73  */
74 #define	H		_QUAD_HIGHWORD
75 #define	L		_QUAD_LOWWORD
76 
77 /*
78  * Total number of bits in a quad_t and in the pieces that make it up.
79  * These are used for shifting, and also below for halfword extraction
80  * and assembly.
81  */
82 #define	QUAD_BITS	(sizeof(quad_t) * CHAR_BIT)
83 #define	HALF_BITS	(sizeof(int) * 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 
98 quad_t		__divdi3(quad_t a, quad_t b);
99 quad_t		__moddi3(quad_t a, quad_t b);
100 u_quad_t	__udivmoddi4(u_quad_t u, u_quad_t v, u_quad_t *rem);
101 u_quad_t	__udivdi3(u_quad_t a, u_quad_t b);
102 u_quad_t	__umoddi3(u_quad_t a, u_quad_t b);
103 
104 /*
105  * XXX
106  * Compensate for gcc 1 vs gcc 2.  Gcc 1 defines ?sh?di3's second argument
107  * as u_quad_t, while gcc 2 correctly uses int.  Unfortunately, we still use
108  * both compilers.
109  */
110 #if __GNUC__ >= 2
111 typedef unsigned int	qshift_t;
112 #else
113 typedef u_quad_t	qshift_t;
114 #endif
115