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git.proxmox.com Git - mirror_ubuntu-artful-kernel.git/blob - lib/gen_crc32table.c
5 #define ENTRIES_PER_LINE 4
8 #define LE_TABLE_SIZE (1 << CRC_LE_BITS)
10 #define LE_TABLE_SIZE 256
14 #define BE_TABLE_SIZE (1 << CRC_BE_BITS)
16 #define BE_TABLE_SIZE 256
19 static uint32_t crc32table_le
[4][256];
20 static uint32_t crc32table_be
[4][256];
23 * crc32init_le() - allocate and initialize LE table data
25 * crc is the crc of the byte i; other entries are filled in based on the
26 * fact that crctable[i^j] = crctable[i] ^ crctable[j].
29 static void crc32init_le(void)
34 crc32table_le
[0][0] = 0;
36 for (i
= LE_TABLE_SIZE
>> 1; i
; i
>>= 1) {
37 crc
= (crc
>> 1) ^ ((crc
& 1) ? CRCPOLY_LE
: 0);
38 for (j
= 0; j
< LE_TABLE_SIZE
; j
+= 2 * i
)
39 crc32table_le
[0][i
+ j
] = crc
^ crc32table_le
[0][j
];
41 for (i
= 0; i
< LE_TABLE_SIZE
; i
++) {
42 crc
= crc32table_le
[0][i
];
43 for (j
= 1; j
< 4; j
++) {
44 crc
= crc32table_le
[0][crc
& 0xff] ^ (crc
>> 8);
45 crc32table_le
[j
][i
] = crc
;
51 * crc32init_be() - allocate and initialize BE table data
53 static void crc32init_be(void)
56 uint32_t crc
= 0x80000000;
58 crc32table_be
[0][0] = 0;
60 for (i
= 1; i
< BE_TABLE_SIZE
; i
<<= 1) {
61 crc
= (crc
<< 1) ^ ((crc
& 0x80000000) ? CRCPOLY_BE
: 0);
62 for (j
= 0; j
< i
; j
++)
63 crc32table_be
[0][i
+ j
] = crc
^ crc32table_be
[0][j
];
65 for (i
= 0; i
< BE_TABLE_SIZE
; i
++) {
66 crc
= crc32table_be
[0][i
];
67 for (j
= 1; j
< 4; j
++) {
68 crc
= crc32table_be
[0][(crc
>> 24) & 0xff] ^ (crc
<< 8);
69 crc32table_be
[j
][i
] = crc
;
74 static void output_table(uint32_t (*table
)[256], int len
, char *trans
)
78 for (j
= 0 ; j
< 4; j
++) {
80 for (i
= 0; i
< len
- 1; i
++) {
81 if (i
% ENTRIES_PER_LINE
== 0)
83 printf("%s(0x%8.8xL), ", trans
, table
[j
][i
]);
85 printf("%s(0x%8.8xL)},\n", trans
, table
[j
][len
- 1]);
89 int main(int argc
, char** argv
)
91 printf("/* this file is generated - do not edit */\n\n");
93 if (CRC_LE_BITS
> 1) {
95 printf("static const u32 crc32table_le[4][256] = {");
96 output_table(crc32table_le
, LE_TABLE_SIZE
, "tole");
100 if (CRC_BE_BITS
> 1) {
102 printf("static const u32 crc32table_be[4][256] = {");
103 output_table(crc32table_be
, BE_TABLE_SIZE
, "tobe");