xref: /freebsd/sys/dev/random/uint128.h (revision 1d386b48a555f61cb7325543adbbb5c3f3407a66)
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 #include <sys/endian.h>
31 
32 /* This whole thing is a crock :-(
33  *
34  * Everyone knows you always need the __uint128_t types!
35  */
36 
37 #ifdef __SIZEOF_INT128__
38 #define	USE_REAL_UINT128_T
39 #endif
40 
41 #ifdef USE_REAL_UINT128_T
42 typedef __uint128_t uint128_t;
43 #define	UINT128_ZERO 0ULL
44 #else
45 typedef struct {
46 	/* Ignore endianness */
47 	uint64_t u128t_word0;
48 	uint64_t u128t_word1;
49 } uint128_t;
50 static const uint128_t very_long_zero = {0UL,0UL};
51 #define	UINT128_ZERO very_long_zero
52 #endif
53 
54 static __inline void
55 uint128_increment(uint128_t *big_uintp)
56 {
57 #ifdef USE_REAL_UINT128_T
58 	(*big_uintp)++;
59 #else
60 	big_uintp->u128t_word0++;
61 	if (big_uintp->u128t_word0 == 0UL)
62 		big_uintp->u128t_word1++;
63 #endif
64 }
65 
66 static __inline void
67 uint128_add64(uint128_t *big_uintp, uint64_t add)
68 {
69 #ifdef USE_REAL_UINT128_T
70 	(*big_uintp) += add;
71 #else
72 	uint64_t word0p;
73 
74 	word0p = big_uintp->u128t_word0 + add;
75 	if (word0p < big_uintp->u128t_word0)
76 		big_uintp->u128t_word1++;
77 	big_uintp->u128t_word0 = word0p;
78 #endif
79 }
80 
81 static __inline bool
82 uint128_equals(uint128_t a, uint128_t b)
83 {
84 #ifdef USE_REAL_UINT128_T
85 	return (a == b);
86 #else
87 	return (a.u128t_word0 == b.u128t_word0 &&
88 	    a.u128t_word1 == b.u128t_word1);
89 #endif
90 }
91 
92 static __inline int
93 uint128_is_zero(uint128_t big_uint)
94 {
95 	return (uint128_equals(big_uint, UINT128_ZERO));
96 }
97 
98 static __inline uint128_t
99 le128dec(const void *pp)
100 {
101 	const uint8_t *p = pp;
102 
103 #ifdef USE_REAL_UINT128_T
104 	return (((uint128_t)le64dec(p + 8) << 64) | le64dec(p));
105 #else
106 	return ((uint128_t){
107 	    .u128t_word0 = le64dec(p),
108 	    .u128t_word1 = le64dec(p + 8),
109 	    });
110 #endif
111 }
112 
113 static __inline void
114 le128enc(void *pp, uint128_t u)
115 {
116 	uint8_t *p = pp;
117 
118 #ifdef USE_REAL_UINT128_T
119 	le64enc(p, (uint64_t)(u & UINT64_MAX));
120 	le64enc(p + 8, (uint64_t)(u >> 64));
121 #else
122 	le64enc(p, u.u128t_word0);
123 	le64enc(p + 8, u.u128t_word1);
124 #endif
125 }
126 
127 #endif /* SYS_DEV_RANDOM_UINT128_H_INCLUDED */
128