Linux kernel mirror (for testing)
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linux
1// SPDX-License-Identifier: GPL-2.0
2#include <stdio.h>
3#include "../../include/linux/crc32poly.h"
4#include "../../include/generated/autoconf.h"
5#include <inttypes.h>
6
7static uint32_t crc32table_le[256];
8static uint32_t crc32table_be[256];
9static uint32_t crc32ctable_le[256];
10
11/**
12 * crc32init_le() - allocate and initialize LE table data
13 *
14 * crc is the crc of the byte i; other entries are filled in based on the
15 * fact that crctable[i^j] = crctable[i] ^ crctable[j].
16 *
17 */
18static void crc32init_le_generic(const uint32_t polynomial, uint32_t tab[256])
19{
20 unsigned i, j;
21 uint32_t crc = 1;
22
23 tab[0] = 0;
24
25 for (i = 128; i; i >>= 1) {
26 crc = (crc >> 1) ^ ((crc & 1) ? polynomial : 0);
27 for (j = 0; j < 256; j += 2 * i)
28 tab[i + j] = crc ^ tab[j];
29 }
30}
31
32static void crc32init_le(void)
33{
34 crc32init_le_generic(CRC32_POLY_LE, crc32table_le);
35}
36
37static void crc32cinit_le(void)
38{
39 crc32init_le_generic(CRC32C_POLY_LE, crc32ctable_le);
40}
41
42/**
43 * crc32init_be() - allocate and initialize BE table data
44 */
45static void crc32init_be(void)
46{
47 unsigned i, j;
48 uint32_t crc = 0x80000000;
49
50 crc32table_be[0] = 0;
51
52 for (i = 1; i < 256; i <<= 1) {
53 crc = (crc << 1) ^ ((crc & 0x80000000) ? CRC32_POLY_BE : 0);
54 for (j = 0; j < i; j++)
55 crc32table_be[i + j] = crc ^ crc32table_be[j];
56 }
57}
58
59static void output_table(const uint32_t table[256])
60{
61 int i;
62
63 for (i = 0; i < 256; i += 4) {
64 printf("\t0x%08x, 0x%08x, 0x%08x, 0x%08x,\n",
65 table[i], table[i + 1], table[i + 2], table[i + 3]);
66 }
67}
68
69int main(int argc, char** argv)
70{
71 printf("/* this file is generated - do not edit */\n\n");
72
73 crc32init_le();
74 printf("static const u32 ____cacheline_aligned crc32table_le[256] = {\n");
75 output_table(crc32table_le);
76 printf("};\n");
77
78 crc32init_be();
79 printf("static const u32 ____cacheline_aligned crc32table_be[256] = {\n");
80 output_table(crc32table_be);
81 printf("};\n");
82
83 crc32cinit_le();
84 printf("static const u32 ____cacheline_aligned crc32ctable_le[256] = {\n");
85 output_table(crc32ctable_le);
86 printf("};\n");
87
88 return 0;
89}