xref: /third_party/FreeBSD/sys/dev/random/uint128.h (revision f9f848fa)
1/*-
2 * Copyright (c) 2015 Mark R V Murray
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer
10 *    in this position and unchanged.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26
27#ifndef SYS_DEV_RANDOM_UINT128_H_INCLUDED
28#define	SYS_DEV_RANDOM_UINT128_H_INCLUDED
29
30/* This whole thing is a crock :-(
31 *
32 * Everyone knows you always need the __uint128_t types!
33 */
34
35#ifdef __SIZEOF_INT128__
36#define	USE_REAL_UINT128_T
37#endif
38
39#ifdef USE_REAL_UINT128_T
40typedef __uint128_t uint128_t;
41#define	UINT128_ZERO 0ULL
42#else
43typedef struct {
44	/* Ignore endianness */
45	uint64_t u128t_word0;
46	uint64_t u128t_word1;
47} uint128_t;
48static const uint128_t very_long_zero = {0UL,0UL};
49#define	UINT128_ZERO very_long_zero
50#endif
51
52static __inline void
53uint128_increment(uint128_t *big_uintp)
54{
55#ifdef USE_REAL_UINT128_T
56	(*big_uintp)++;
57#else
58	big_uintp->u128t_word0++;
59	if (big_uintp->u128t_word0 == 0UL)
60		big_uintp->u128t_word1++;
61#endif
62}
63
64static __inline void
65uint128_add64(uint128_t *big_uintp, uint64_t add)
66{
67#ifdef USE_REAL_UINT128_T
68	(*big_uintp) += add;
69#else
70	uint64_t word0p;
71
72	word0p = big_uintp->u128t_word0 + add;
73	if (word0p < big_uintp->u128t_word0)
74		big_uintp->u128t_word1++;
75	big_uintp->u128t_word0 = word0p;
76#endif
77}
78
79static __inline bool
80uint128_equals(uint128_t a, uint128_t b)
81{
82#ifdef USE_REAL_UINT128_T
83	return (a == b);
84#else
85	return (a.u128t_word0 == b.u128t_word0 &&
86	    a.u128t_word1 == b.u128t_word1);
87#endif
88}
89
90static __inline int
91uint128_is_zero(uint128_t big_uint)
92{
93	return (uint128_equals(big_uint, UINT128_ZERO));
94}
95
96#endif /* SYS_DEV_RANDOM_UINT128_H_INCLUDED */
97