1 #ident "$Id: mktables.c,v 1.2 2002/12/12 22:41:27 hpa Exp $"
2 /* ----------------------------------------------------------------------- *
4 * Copyright 2002 H. Peter Anvin - All Rights Reserved
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation, Inc., 53 Temple Place Ste 330,
9 * Bostom MA 02111-1307, USA; either version 2 of the License, or
10 * (at your option) any later version; incorporated herein by reference.
12 * ----------------------------------------------------------------------- */
17 * Make RAID-6 tables. This is a host user space program to be run at
27 static uint8_t gfmul(uint8_t a, uint8_t b)
34 a = (a << 1) ^ (a & 0x80 ? 0x1d : 0);
41 static uint8_t gfpow(uint8_t a, int b)
59 int main(int argc, char *argv[])
63 uint8_t exptbl[256], invtbl[256];
65 printf("#include \"raid6.h\"\n");
67 /* Compute multiplication table */
68 printf("\nconst u8 __attribute__((aligned(256)))\n"
69 "raid6_gfmul[256][256] =\n"
71 for (i = 0; i < 256; i++) {
73 for (j = 0; j < 256; j += 8) {
75 for (k = 0; k < 8; k++)
76 printf("0x%02x, ", gfmul(i, j+k));
83 /* Compute power-of-2 table (exponent) */
85 printf("\nconst u8 __attribute__((aligned(256)))\n"
86 "raid6_gfexp[256] =\n"
88 for (i = 0; i < 256; i += 8) {
90 for (j = 0; j < 8; j++) {
92 printf("0x%02x, ", v);
95 v = 0; /* For entry 255, not a real entry */
101 /* Compute inverse table x^-1 == x^254 */
102 printf("\nconst u8 __attribute__((aligned(256)))\n"
103 "raid6_gfinv[256] =\n"
105 for (i = 0; i < 256; i += 8) {
107 for (j = 0; j < 8; j++) {
110 printf("0x%02x, ", v);
116 /* Compute inv(2^x + 1) (exponent-xor-inverse) table */
117 printf("\nconst u8 __attribute__((aligned(256)))\n"
118 "raid6_gfexi[256] =\n"
120 for (i = 0; i < 256; i += 8) {
122 for (j = 0; j < 8; j++)
123 printf("0x%02x, ", invtbl[exptbl[i+j]^1]);