xref: /freebsd/sys/dev/random/uint128.h (revision bdd1243df58e60e85101c09001d9812a789b6bc4)
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  * $FreeBSD$
27  */
28 
29 #ifndef SYS_DEV_RANDOM_UINT128_H_INCLUDED
30 #define	SYS_DEV_RANDOM_UINT128_H_INCLUDED
31 
32 #include <sys/endian.h>
33 
34 /* This whole thing is a crock :-(
35  *
36  * Everyone knows you always need the __uint128_t types!
37  */
38 
39 #ifdef __SIZEOF_INT128__
40 #define	USE_REAL_UINT128_T
41 #endif
42 
43 #ifdef USE_REAL_UINT128_T
44 typedef __uint128_t uint128_t;
45 #define	UINT128_ZERO 0ULL
46 #else
47 typedef struct {
48 	/* Ignore endianness */
49 	uint64_t u128t_word0;
50 	uint64_t u128t_word1;
51 } uint128_t;
52 static const uint128_t very_long_zero = {0UL,0UL};
53 #define	UINT128_ZERO very_long_zero
54 #endif
55 
56 static __inline void
57 uint128_increment(uint128_t *big_uintp)
58 {
59 #ifdef USE_REAL_UINT128_T
60 	(*big_uintp)++;
61 #else
62 	big_uintp->u128t_word0++;
63 	if (big_uintp->u128t_word0 == 0UL)
64 		big_uintp->u128t_word1++;
65 #endif
66 }
67 
68 static __inline void
69 uint128_add64(uint128_t *big_uintp, uint64_t add)
70 {
71 #ifdef USE_REAL_UINT128_T
72 	(*big_uintp) += add;
73 #else
74 	uint64_t word0p;
75 
76 	word0p = big_uintp->u128t_word0 + add;
77 	if (word0p < big_uintp->u128t_word0)
78 		big_uintp->u128t_word1++;
79 	big_uintp->u128t_word0 = word0p;
80 #endif
81 }
82 
83 static __inline bool
84 uint128_equals(uint128_t a, uint128_t b)
85 {
86 #ifdef USE_REAL_UINT128_T
87 	return (a == b);
88 #else
89 	return (a.u128t_word0 == b.u128t_word0 &&
90 	    a.u128t_word1 == b.u128t_word1);
91 #endif
92 }
93 
94 static __inline int
95 uint128_is_zero(uint128_t big_uint)
96 {
97 	return (uint128_equals(big_uint, UINT128_ZERO));
98 }
99 
100 static __inline uint128_t
101 le128dec(const void *pp)
102 {
103 	const uint8_t *p = pp;
104 
105 #ifdef USE_REAL_UINT128_T
106 	return (((uint128_t)le64dec(p + 8) << 64) | le64dec(p));
107 #else
108 	return ((uint128_t){
109 	    .u128t_word0 = le64dec(p),
110 	    .u128t_word1 = le64dec(p + 8),
111 	    });
112 #endif
113 }
114 
115 static __inline void
116 le128enc(void *pp, uint128_t u)
117 {
118 	uint8_t *p = pp;
119 
120 #ifdef USE_REAL_UINT128_T
121 	le64enc(p, (uint64_t)(u & UINT64_MAX));
122 	le64enc(p + 8, (uint64_t)(u >> 64));
123 #else
124 	le64enc(p, u.u128t_word0);
125 	le64enc(p + 8, u.u128t_word1);
126 #endif
127 }
128 
129 #endif /* SYS_DEV_RANDOM_UINT128_H_INCLUDED */
130