blob: 1702c2876d44d4fa172afc1d3e8fbba27e50a62b (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
|
/*
* Copyright (C) 2013 Andrea Mazzoleni
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#ifndef __RAID_GF_H
#define __RAID_GF_H
/*
* Galois field operations.
*
* Basic range checks are implemented using BUG_ON().
*/
/*
* GF a*b.
*/
static __always_inline uint8_t mul(uint8_t a, uint8_t b)
{
return gfmul[a][b];
}
/*
* GF 1/a.
* Not defined for a == 0.
*/
static __always_inline uint8_t inv(uint8_t v)
{
BUG_ON(v == 0); /* division by zero */
return gfinv[v];
}
/*
* GF 2^a.
*/
static __always_inline uint8_t pow2(int v)
{
BUG_ON(v < 0 || v > 254); /* invalid exponent */
return gfexp[v];
}
/*
* Gets the multiplication table for a specified value.
*/
static __always_inline const uint8_t *table(uint8_t v)
{
return gfmul[v];
}
/*
* Gets the generator matrix coefficient for parity 'p' and disk 'd'.
*/
static __always_inline uint8_t A(int p, int d)
{
return gfgen[p][d];
}
/*
* Dereference as uint8_t
*/
#define v_8(p) (*(uint8_t *)&(p))
/*
* Dereference as uint32_t
*/
#define v_32(p) (*(uint32_t *)&(p))
/*
* Dereference as uint64_t
*/
#define v_64(p) (*(uint64_t *)&(p))
/*
* Multiply each byte of a uint32 by 2 in the GF(2^8).
*/
static __always_inline uint32_t x2_32(uint32_t v)
{
uint32_t mask = v & 0x80808080U;
mask = (mask << 1) - (mask >> 7);
v = (v << 1) & 0xfefefefeU;
v ^= mask & 0x1d1d1d1dU;
return v;
}
/*
* Multiply each byte of a uint64 by 2 in the GF(2^8).
*/
static __always_inline uint64_t x2_64(uint64_t v)
{
uint64_t mask = v & 0x8080808080808080ULL;
mask = (mask << 1) - (mask >> 7);
v = (v << 1) & 0xfefefefefefefefeULL;
v ^= mask & 0x1d1d1d1d1d1d1d1dULL;
return v;
}
/*
* Divide each byte of a uint32 by 2 in the GF(2^8).
*/
static __always_inline uint32_t d2_32(uint32_t v)
{
uint32_t mask = v & 0x01010101U;
mask = (mask << 8) - mask;
v = (v >> 1) & 0x7f7f7f7fU;
v ^= mask & 0x8e8e8e8eU;
return v;
}
/*
* Divide each byte of a uint64 by 2 in the GF(2^8).
*/
static __always_inline uint64_t d2_64(uint64_t v)
{
uint64_t mask = v & 0x0101010101010101ULL;
mask = (mask << 8) - mask;
v = (v >> 1) & 0x7f7f7f7f7f7f7f7fULL;
v ^= mask & 0x8e8e8e8e8e8e8e8eULL;
return v;
}
#endif
|
