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/* $OpenBSD: rf_geniq.c,v 1.5 2002/12/16 07:01:04 tdeval Exp $ */
/* $NetBSD: rf_geniq.c,v 1.3 1999/02/05 00:06:12 oster Exp $ */
/*
* Copyright (c) 1995 Carnegie-Mellon University.
* All rights reserved.
*
* Author: Daniel Stodolsky
*
* Permission to use, copy, modify and distribute this software and
* its documentation is hereby granted, provided that both the copyright
* notice and this permission notice appear in all copies of the
* software, derivative works or modified versions, and any portions
* thereof, and that both notices appear in supporting documentation.
*
* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
* FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
*
* Carnegie Mellon requests users of this software to return to
*
* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
* School of Computer Science
* Carnegie Mellon University
* Pittsburgh PA 15213-3890
*
* any improvements or extensions that they make and grant Carnegie the
* rights to redistribute these changes.
*/
/*
* rf_geniq.c -- Code which implements Reed-Solomon encoding for RAID level 6.
*/
#define RF_UTILITY 1
#include "rf_pqdeg.h"
/*
* five bit lfsr
* poly - feedback connections
*
* val = value;
*/
int
lsfr_shift(unsigned val, unsigned poly)
{
unsigned new;
unsigned int i;
unsigned high = (val >> 4) & 1;
unsigned bit;
new = (poly & 1) ? high : 0;
for (i = 1; i <= 4; i++) {
bit = (val >> (i - 1)) & 1;
if (poly & (1 << i)) /* There is a feedback connection. */
new = new | ((bit ^ high) << i);
else
new = new | (bit << i);
}
return new;
}
/* Generate Q matrices for the data. */
RF_ua32_t rf_qfor[32];
int
main(void)
{
unsigned int i, j, l, a, b;
unsigned int val;
unsigned int r;
unsigned int m, p, q;
RF_ua32_t k;
printf("/*\n");
printf(" * rf_invertq.h\n");
printf(" */\n");
printf("/*\n");
printf(" * GENERATED FILE -- DO NOT EDIT\n");
printf(" */\n");
printf("\n");
printf("#ifndef\t_RF__RF_INVERTQ_H_\n");
printf("#define\t_RF__RF_INVERTQ_H_\n");
printf("\n");
printf("/*\n");
printf(" * rf_geniq.c must include rf_archs.h before including\n");
printf(" * this file (to get VPATH magic right with the way we\n");
printf(" * generate this file in kernel trees).\n");
printf(" */\n");
printf("/* #include \"rf_archs.h\" */\n");
printf("\n");
printf("#if\t(RF_INCLUDE_PQ > 0) || (RF_INCLUDE_RAID6 > 0)\n");
printf("\n");
printf("#define\tRF_Q_COLS\t32\n");
printf("RF_ua32_t rf_rn = {");
k[0] = 1;
for (j = 0; j < 31; j++)
k[j + 1] = lsfr_shift(k[j], 5);
for (j = 0; j < 32; j++)
printf("%d, ", k[j]);
printf("};\n");
printf("RF_ua32_t rf_qfor[32] = {\n");
for (i = 0; i < 32; i++) {
printf("/* i = %d */\t{0, ", i);
rf_qfor[i][0] = 0;
for (j = 1; j < 32; j++) {
val = j;
for (l = 0; l < i; l++)
val = lsfr_shift(val, 5);
rf_qfor[i][j] = val;
printf("%d, ", val);
}
printf("},\n");
}
printf("};\n");
printf("#define\tRF_Q_DATA_COL(col_num)\trf_rn[col_num],"
" rf_qfor[28-(col_num)]\n");
/* generate the inverse tables. (i,j,p,q) */
/* The table just stores a. Get b back from the parity */
printf("#ifdef\t_KERNEL\n");
printf("RF_ua1024_t rf_qinv[1];\t/* don't compile monster table"
" into kernel */\n");
printf("#elif\tdefined(NO_PQ)\n");
printf("RF_ua1024_t rf_qinv[29*29];\n");
printf("#else\t/* !_KERNEL && NO_PQ */\n");
printf("RF_ua1024_t rf_qinv[29*29] = {\n");
for (i = 0; i < 29; i++) {
for (j = 0; j < 29; j++) {
printf("/* i %d, j %d */\t{", i, j);
if (i == j)
for (l = 0; l < 1023; l++)
printf("0, ");
else {
for (p = 0; p < 32; p++)
for (q = 0; q < 32; q++) {
/*
* What are a, b such that a ^
* b == p; and qfor[(28-i)][a
* ^ rf_rn[i+1]] ^
* qfor[(28-j)][b ^
* rf_rn[j+1]] == q. Solve by
* guessing a. Then testing.
*/
for (a = 0; a < 32; a++) {
b = a ^ p;
if ((rf_qfor[28 - i]
[a ^ k[i + 1]] ^
rf_qfor[28 - j]
[b ^ k[j + 1]]) ==
q)
break;
}
if (a == 32)
printf("unable to solve"
" %d %d %d %d\n",
i, j, p, q);
printf("%d, ", a);
}
}
printf("},\n");
}
}
printf("};\n");
printf("\n#endif\t/* (RF_INCLUDE_PQ > 0) || (RF_INCLUDE_RAID6 > 0) */"
"\n\n");
printf("#endif\t/* !_KERNEL && NO_PQ */\n");
printf("#endif\t/* !_RF__RF_INVERTQ_H_ */\n");
exit(0);
}
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