rf_geniq.c revision 1.3 1 /* $NetBSD: rf_geniq.c,v 1.3 1999/02/05 00:06:12 oster Exp $ */
2 /*
3 * Copyright (c) 1995 Carnegie-Mellon University.
4 * All rights reserved.
5 *
6 * Author: Daniel Stodolsky
7 *
8 * Permission to use, copy, modify and distribute this software and
9 * its documentation is hereby granted, provided that both the copyright
10 * notice and this permission notice appear in all copies of the
11 * software, derivative works or modified versions, and any portions
12 * thereof, and that both notices appear in supporting documentation.
13 *
14 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
15 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
16 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
17 *
18 * Carnegie Mellon requests users of this software to return to
19 *
20 * Software Distribution Coordinator or Software.Distribution (at) CS.CMU.EDU
21 * School of Computer Science
22 * Carnegie Mellon University
23 * Pittsburgh PA 15213-3890
24 *
25 * any improvements or extensions that they make and grant Carnegie the
26 * rights to redistribute these changes.
27 */
28
29 /* rf_geniq.c
30 * code which implements Reed-Solomon encoding for RAID level 6
31 */
32
33
34 #define RF_UTILITY 1
35 #include "rf_pqdeg.h"
36
37 /*
38 five bit lfsr
39 poly - feedback connections
40
41 val = value;
42 */
43 int
44 lsfr_shift(val, poly)
45 unsigned val, poly;
46 {
47 unsigned new;
48 unsigned int i;
49 unsigned high = (val >> 4) & 1;
50 unsigned bit;
51
52 new = (poly & 1) ? high : 0;
53
54 for (i = 1; i <= 4; i++) {
55 bit = (val >> (i - 1)) & 1;
56 if (poly & (1 << i)) /* there is a feedback connection */
57 new = new | ((bit ^ high) << i);
58 else
59 new = new | (bit << i);
60 }
61 return new;
62 }
63 /* generate Q matricies for the data */
64
65 RF_ua32_t rf_qfor[32];
66
67 void
68 main()
69 {
70 unsigned int i, j, l, a, b;
71 unsigned int val;
72 unsigned int r;
73 unsigned int m, p, q;
74
75 RF_ua32_t k;
76
77 printf("/*\n");
78 printf(" * rf_invertq.h\n");
79 printf(" */\n");
80 printf("/*\n");
81 printf(" * GENERATED FILE -- DO NOT EDIT\n");
82 printf(" */\n");
83 printf("\n");
84 printf("#ifndef _RF__RF_INVERTQ_H_\n");
85 printf("#define _RF__RF_INVERTQ_H_\n");
86 printf("\n");
87 printf("/*\n");
88 printf(" * rf_geniq.c must include rf_archs.h before including\n");
89 printf(" * this file (to get VPATH magic right with the way we\n");
90 printf(" * generate this file in kernel trees)\n");
91 printf(" */\n");
92 printf("/* #include \"rf_archs.h\" */\n");
93 printf("\n");
94 printf("#if (RF_INCLUDE_PQ > 0) || (RF_INCLUDE_RAID6 > 0)\n");
95 printf("\n");
96 printf("#define RF_Q_COLS 32\n");
97 printf("RF_ua32_t rf_rn = {\n");
98 k[0] = 1;
99 for (j = 0; j < 31; j++)
100 k[j + 1] = lsfr_shift(k[j], 5);
101 for (j = 0; j < 32; j++)
102 printf("%d, ", k[j]);
103 printf("};\n");
104
105 printf("RF_ua32_t rf_qfor[32] = {\n");
106 for (i = 0; i < 32; i++) {
107 printf("/* i = %d */ { 0, ", i);
108 rf_qfor[i][0] = 0;
109 for (j = 1; j < 32; j++) {
110 val = j;
111 for (l = 0; l < i; l++)
112 val = lsfr_shift(val, 5);
113 rf_qfor[i][j] = val;
114 printf("%d, ", val);
115 }
116 printf("},\n");
117 }
118 printf("};\n");
119 printf("#define RF_Q_DATA_COL(col_num) rf_rn[col_num],rf_qfor[28-(col_num)]\n");
120
121 /* generate the inverse tables. (i,j,p,q) */
122 /* The table just stores a. Get b back from the parity */
123 printf("#ifdef KERNEL\n");
124 printf("RF_ua1024_t rf_qinv[1]; /* don't compile monster table into kernel */\n");
125 printf("#elif defined(NO_PQ)\n");
126 printf("RF_ua1024_t rf_qinv[29*29];\n");
127 printf("#else /* !KERNEL && NO_PQ */\n");
128 printf("RF_ua1024_t rf_qinv[29*29] = {\n");
129 for (i = 0; i < 29; i++) {
130 for (j = 0; j < 29; j++) {
131 printf("/* i %d, j %d */{ ", i, j);
132 if (i == j)
133 for (l = 0; l < 1023; l++)
134 printf("0, ");
135 else {
136 for (p = 0; p < 32; p++)
137 for (q = 0; q < 32; q++) {
138 /* What are a, b such that a ^
139 * b = p; and qfor[(28-i)][a
140 * ^ rf_rn[i+1]] ^
141 * qfor[(28-j)][b ^
142 * rf_rn[j+1]] = q. Solve by
143 * guessing a. Then testing. */
144 for (a = 0; a < 32; a++) {
145 b = a ^ p;
146 if ((rf_qfor[28 - i][a ^ k[i + 1]] ^ rf_qfor[28 - j][b ^ k[j + 1]]) == q)
147 break;
148 }
149 if (a == 32)
150 printf("unable to solve %d %d %d %d\n", i, j, p, q);
151 printf("%d,", a);
152 }
153 }
154 printf("},\n");
155 }
156 }
157 printf("};\n");
158 printf("\n#endif /* (RF_INCLUDE_PQ > 0) || (RF_INCLUDE_RAID6 > 0) */\n\n");
159 printf("#endif /* !KERNEL && NO_PQ */\n");
160 printf("#endif /* !_RF__RF_INVERTQ_H_ */\n");
161 exit(0);
162 }
163