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Annotation of /alx-src/tags/kernel26-2.6.12-alx-r9/lib/gen_crc32table.c

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Revision 630 - (hide annotations) (download)
Wed Mar 4 11:03:09 2009 UTC (15 years, 3 months ago) by niro
File MIME type: text/plain
File size: 1820 byte(s)
Tag kernel26-2.6.12-alx-r9
1 niro 628 #include <stdio.h>
2     #include "crc32defs.h"
3     #include <inttypes.h>
4    
5     #define ENTRIES_PER_LINE 4
6    
7     #define LE_TABLE_SIZE (1 << CRC_LE_BITS)
8     #define BE_TABLE_SIZE (1 << CRC_BE_BITS)
9    
10     static uint32_t crc32table_le[LE_TABLE_SIZE];
11     static uint32_t crc32table_be[BE_TABLE_SIZE];
12    
13     /**
14     * crc32init_le() - allocate and initialize LE table data
15     *
16     * crc is the crc of the byte i; other entries are filled in based on the
17     * fact that crctable[i^j] = crctable[i] ^ crctable[j].
18     *
19     */
20     static void crc32init_le(void)
21     {
22     unsigned i, j;
23     uint32_t crc = 1;
24    
25     crc32table_le[0] = 0;
26    
27     for (i = 1 << (CRC_LE_BITS - 1); i; i >>= 1) {
28     crc = (crc >> 1) ^ ((crc & 1) ? CRCPOLY_LE : 0);
29     for (j = 0; j < LE_TABLE_SIZE; j += 2 * i)
30     crc32table_le[i + j] = crc ^ crc32table_le[j];
31     }
32     }
33    
34     /**
35     * crc32init_be() - allocate and initialize BE table data
36     */
37     static void crc32init_be(void)
38     {
39     unsigned i, j;
40     uint32_t crc = 0x80000000;
41    
42     crc32table_be[0] = 0;
43    
44     for (i = 1; i < BE_TABLE_SIZE; i <<= 1) {
45     crc = (crc << 1) ^ ((crc & 0x80000000) ? CRCPOLY_BE : 0);
46     for (j = 0; j < i; j++)
47     crc32table_be[i + j] = crc ^ crc32table_be[j];
48     }
49     }
50    
51     static void output_table(uint32_t table[], int len, char *trans)
52     {
53     int i;
54    
55     for (i = 0; i < len - 1; i++) {
56     if (i % ENTRIES_PER_LINE == 0)
57     printf("\n");
58     printf("%s(0x%8.8xL), ", trans, table[i]);
59     }
60     printf("%s(0x%8.8xL)\n", trans, table[len - 1]);
61     }
62    
63     int main(int argc, char** argv)
64     {
65     printf("/* this file is generated - do not edit */\n\n");
66    
67     if (CRC_LE_BITS > 1) {
68     crc32init_le();
69     printf("static const u32 crc32table_le[] = {");
70     output_table(crc32table_le, LE_TABLE_SIZE, "tole");
71     printf("};\n");
72     }
73    
74     if (CRC_BE_BITS > 1) {
75     crc32init_be();
76     printf("static const u32 crc32table_be[] = {");
77     output_table(crc32table_be, BE_TABLE_SIZE, "tobe");
78     printf("};\n");
79     }
80    
81     return 0;
82     }