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Commit | Line | Data |
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98ec302b | 1 | /* -*- linux-c -*- ------------------------------------------------------- * |
1da177e4 | 2 | * |
98ec302b | 3 | * Copyright 2002-2007 H. Peter Anvin - All Rights Reserved |
1da177e4 | 4 | * |
98ec302b PA |
5 | * This file is part of the Linux kernel, and is made available under |
6 | * the terms of the GNU General Public License version 2 or (at your | |
7 | * option) any later version; incorporated herein by reference. | |
1da177e4 LT |
8 | * |
9 | * ----------------------------------------------------------------------- */ | |
10 | ||
11 | /* | |
12 | * mktables.c | |
13 | * | |
14 | * Make RAID-6 tables. This is a host user space program to be run at | |
15 | * compile time. | |
16 | */ | |
17 | ||
18 | #include <stdio.h> | |
19 | #include <string.h> | |
20 | #include <inttypes.h> | |
21 | #include <stdlib.h> | |
22 | #include <time.h> | |
23 | ||
24 | static uint8_t gfmul(uint8_t a, uint8_t b) | |
25 | { | |
54212cf4 OP |
26 | uint8_t v = 0; |
27 | ||
28 | while (b) { | |
29 | if (b & 1) | |
30 | v ^= a; | |
31 | a = (a << 1) ^ (a & 0x80 ? 0x1d : 0); | |
32 | b >>= 1; | |
33 | } | |
34 | ||
35 | return v; | |
1da177e4 LT |
36 | } |
37 | ||
38 | static uint8_t gfpow(uint8_t a, int b) | |
39 | { | |
54212cf4 OP |
40 | uint8_t v = 1; |
41 | ||
42 | b %= 255; | |
43 | if (b < 0) | |
44 | b += 255; | |
45 | ||
46 | while (b) { | |
47 | if (b & 1) | |
48 | v = gfmul(v, a); | |
49 | a = gfmul(a, a); | |
50 | b >>= 1; | |
51 | } | |
52 | ||
53 | return v; | |
1da177e4 LT |
54 | } |
55 | ||
56 | int main(int argc, char *argv[]) | |
57 | { | |
54212cf4 OP |
58 | int i, j, k; |
59 | uint8_t v; | |
60 | uint8_t exptbl[256], invtbl[256]; | |
61 | ||
62 | printf("#include \"raid6.h\"\n"); | |
63 | ||
64 | /* Compute multiplication table */ | |
65 | printf("\nconst u8 __attribute__((aligned(256)))\n" | |
66 | "raid6_gfmul[256][256] =\n" | |
67 | "{\n"); | |
68 | for (i = 0; i < 256; i++) { | |
69 | printf("\t{\n"); | |
70 | for (j = 0; j < 256; j += 8) { | |
71 | printf("\t\t"); | |
72 | for (k = 0; k < 8; k++) | |
98ec302b PA |
73 | printf("0x%02x,%c", gfmul(i, j + k), |
74 | (k == 7) ? '\n' : ' '); | |
54212cf4 OP |
75 | } |
76 | printf("\t},\n"); | |
77 | } | |
78 | printf("};\n"); | |
79 | ||
80 | /* Compute power-of-2 table (exponent) */ | |
81 | v = 1; | |
82 | printf("\nconst u8 __attribute__((aligned(256)))\n" | |
98ec302b | 83 | "raid6_gfexp[256] =\n" "{\n"); |
54212cf4 OP |
84 | for (i = 0; i < 256; i += 8) { |
85 | printf("\t"); | |
86 | for (j = 0; j < 8; j++) { | |
98ec302b PA |
87 | exptbl[i + j] = v; |
88 | printf("0x%02x,%c", v, (j == 7) ? '\n' : ' '); | |
54212cf4 OP |
89 | v = gfmul(v, 2); |
90 | if (v == 1) | |
91 | v = 0; /* For entry 255, not a real entry */ | |
92 | } | |
54212cf4 OP |
93 | } |
94 | printf("};\n"); | |
95 | ||
96 | /* Compute inverse table x^-1 == x^254 */ | |
97 | printf("\nconst u8 __attribute__((aligned(256)))\n" | |
98ec302b | 98 | "raid6_gfinv[256] =\n" "{\n"); |
54212cf4 OP |
99 | for (i = 0; i < 256; i += 8) { |
100 | printf("\t"); | |
101 | for (j = 0; j < 8; j++) { | |
98ec302b PA |
102 | invtbl[i + j] = v = gfpow(i + j, 254); |
103 | printf("0x%02x,%c", v, (j == 7) ? '\n' : ' '); | |
54212cf4 | 104 | } |
54212cf4 OP |
105 | } |
106 | printf("};\n"); | |
107 | ||
108 | /* Compute inv(2^x + 1) (exponent-xor-inverse) table */ | |
109 | printf("\nconst u8 __attribute__((aligned(256)))\n" | |
98ec302b | 110 | "raid6_gfexi[256] =\n" "{\n"); |
54212cf4 OP |
111 | for (i = 0; i < 256; i += 8) { |
112 | printf("\t"); | |
113 | for (j = 0; j < 8; j++) | |
98ec302b PA |
114 | printf("0x%02x,%c", invtbl[exptbl[i + j] ^ 1], |
115 | (j == 7) ? '\n' : ' '); | |
54212cf4 | 116 | } |
98ec302b | 117 | printf("};\n"); |
54212cf4 OP |
118 | |
119 | return 0; | |
1da177e4 | 120 | } |