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Louis Yung-Chieh Lo49fa8e52010-04-30 16:10:48 -07001/* CRC32 implementation by Gary S. Brown. See license claim below. */
2
3/* ============================================================= */
4/* COPYRIGHT (C) 1986 Gary S. Brown. You may use this program, or */
5/* code or tables extracted from it, as desired without restriction. */
6/* */
7/* First, the polynomial itself and its table of feedback terms. The */
8/* polynomial is */
9/* X^32+X^26+X^23+X^22+X^16+X^12+X^11+X^10+X^8+X^7+X^5+X^4+X^2+X^1+X^0 */
10/* */
11/* Note that we take it "backwards" and put the highest-order term in */
12/* the lowest-order bit. The X^32 term is "implied"; the LSB is the */
13/* X^31 term, etc. The X^0 term (usually shown as "+1") results in */
14/* the MSB being 1. */
15/* */
16/* Note that the usual hardware shift register implementation, which */
17/* is what we're using (we're merely optimizing it by doing eight-bit */
18/* chunks at a time) shifts bits into the lowest-order term. In our */
19/* implementation, that means shifting towards the right. Why do we */
20/* do it this way? Because the calculated CRC must be transmitted in */
21/* order from highest-order term to lowest-order term. UARTs transmit */
22/* characters in order from LSB to MSB. By storing the CRC this way, */
23/* we hand it to the UART in the order low-byte to high-byte; the UART */
24/* sends each low-bit to hight-bit; and the result is transmission bit */
25/* by bit from highest- to lowest-order term without requiring any bit */
26/* shuffling on our part. Reception works similarly. */
27/* */
28/* The feedback terms table consists of 256, 32-bit entries. Notes: */
29/* */
30/* The table can be generated at runtime if desired; code to do so */
31/* is shown later. It might not be obvious, but the feedback */
32/* terms simply represent the results of eight shift/xor opera- */
33/* tions for all combinations of data and CRC register values. */
34/* */
35/* The values must be right-shifted by eight bits by the "updcrc" */
36/* logic; the shift must be unsigned (bring in zeroes). On some */
37/* hardware you could probably optimize the shift in assembler by */
38/* using byte-swap instructions. */
39/* polynomial $edb88320 */
40/* */
41/* -------------------------------------------------------------------- */
Bill Richardson0c3ba242013-03-29 11:09:30 -070042
Joel Kitchingffd42a82019-08-29 13:58:52 +080043#include "2sysincludes.h"
Louis Yung-Chieh Lo49fa8e52010-04-30 16:10:48 -070044#include "crc32.h"
Louis Yung-Chieh Lo49fa8e52010-04-30 16:10:48 -070045
46static uint32_t crc32_tab[] = {
Randall Spanglercefe12c2013-01-30 12:52:02 -080047 0x00000000U, 0x77073096U, 0xee0e612cU, 0x990951baU, 0x076dc419U,
48 0x706af48fU, 0xe963a535U, 0x9e6495a3U, 0x0edb8832U, 0x79dcb8a4U,
49 0xe0d5e91eU, 0x97d2d988U, 0x09b64c2bU, 0x7eb17cbdU, 0xe7b82d07U,
50 0x90bf1d91U, 0x1db71064U, 0x6ab020f2U, 0xf3b97148U, 0x84be41deU,
51 0x1adad47dU, 0x6ddde4ebU, 0xf4d4b551U, 0x83d385c7U, 0x136c9856U,
52 0x646ba8c0U, 0xfd62f97aU, 0x8a65c9ecU, 0x14015c4fU, 0x63066cd9U,
53 0xfa0f3d63U, 0x8d080df5U, 0x3b6e20c8U, 0x4c69105eU, 0xd56041e4U,
54 0xa2677172U, 0x3c03e4d1U, 0x4b04d447U, 0xd20d85fdU, 0xa50ab56bU,
55 0x35b5a8faU, 0x42b2986cU, 0xdbbbc9d6U, 0xacbcf940U, 0x32d86ce3U,
56 0x45df5c75U, 0xdcd60dcfU, 0xabd13d59U, 0x26d930acU, 0x51de003aU,
57 0xc8d75180U, 0xbfd06116U, 0x21b4f4b5U, 0x56b3c423U, 0xcfba9599U,
58 0xb8bda50fU, 0x2802b89eU, 0x5f058808U, 0xc60cd9b2U, 0xb10be924U,
59 0x2f6f7c87U, 0x58684c11U, 0xc1611dabU, 0xb6662d3dU, 0x76dc4190U,
60 0x01db7106U, 0x98d220bcU, 0xefd5102aU, 0x71b18589U, 0x06b6b51fU,
61 0x9fbfe4a5U, 0xe8b8d433U, 0x7807c9a2U, 0x0f00f934U, 0x9609a88eU,
62 0xe10e9818U, 0x7f6a0dbbU, 0x086d3d2dU, 0x91646c97U, 0xe6635c01U,
63 0x6b6b51f4U, 0x1c6c6162U, 0x856530d8U, 0xf262004eU, 0x6c0695edU,
64 0x1b01a57bU, 0x8208f4c1U, 0xf50fc457U, 0x65b0d9c6U, 0x12b7e950U,
65 0x8bbeb8eaU, 0xfcb9887cU, 0x62dd1ddfU, 0x15da2d49U, 0x8cd37cf3U,
66 0xfbd44c65U, 0x4db26158U, 0x3ab551ceU, 0xa3bc0074U, 0xd4bb30e2U,
67 0x4adfa541U, 0x3dd895d7U, 0xa4d1c46dU, 0xd3d6f4fbU, 0x4369e96aU,
68 0x346ed9fcU, 0xad678846U, 0xda60b8d0U, 0x44042d73U, 0x33031de5U,
69 0xaa0a4c5fU, 0xdd0d7cc9U, 0x5005713cU, 0x270241aaU, 0xbe0b1010U,
70 0xc90c2086U, 0x5768b525U, 0x206f85b3U, 0xb966d409U, 0xce61e49fU,
71 0x5edef90eU, 0x29d9c998U, 0xb0d09822U, 0xc7d7a8b4U, 0x59b33d17U,
72 0x2eb40d81U, 0xb7bd5c3bU, 0xc0ba6cadU, 0xedb88320U, 0x9abfb3b6U,
73 0x03b6e20cU, 0x74b1d29aU, 0xead54739U, 0x9dd277afU, 0x04db2615U,
74 0x73dc1683U, 0xe3630b12U, 0x94643b84U, 0x0d6d6a3eU, 0x7a6a5aa8U,
75 0xe40ecf0bU, 0x9309ff9dU, 0x0a00ae27U, 0x7d079eb1U, 0xf00f9344U,
76 0x8708a3d2U, 0x1e01f268U, 0x6906c2feU, 0xf762575dU, 0x806567cbU,
77 0x196c3671U, 0x6e6b06e7U, 0xfed41b76U, 0x89d32be0U, 0x10da7a5aU,
78 0x67dd4accU, 0xf9b9df6fU, 0x8ebeeff9U, 0x17b7be43U, 0x60b08ed5U,
79 0xd6d6a3e8U, 0xa1d1937eU, 0x38d8c2c4U, 0x4fdff252U, 0xd1bb67f1U,
80 0xa6bc5767U, 0x3fb506ddU, 0x48b2364bU, 0xd80d2bdaU, 0xaf0a1b4cU,
81 0x36034af6U, 0x41047a60U, 0xdf60efc3U, 0xa867df55U, 0x316e8eefU,
82 0x4669be79U, 0xcb61b38cU, 0xbc66831aU, 0x256fd2a0U, 0x5268e236U,
83 0xcc0c7795U, 0xbb0b4703U, 0x220216b9U, 0x5505262fU, 0xc5ba3bbeU,
84 0xb2bd0b28U, 0x2bb45a92U, 0x5cb36a04U, 0xc2d7ffa7U, 0xb5d0cf31U,
85 0x2cd99e8bU, 0x5bdeae1dU, 0x9b64c2b0U, 0xec63f226U, 0x756aa39cU,
86 0x026d930aU, 0x9c0906a9U, 0xeb0e363fU, 0x72076785U, 0x05005713U,
87 0x95bf4a82U, 0xe2b87a14U, 0x7bb12baeU, 0x0cb61b38U, 0x92d28e9bU,
88 0xe5d5be0dU, 0x7cdcefb7U, 0x0bdbdf21U, 0x86d3d2d4U, 0xf1d4e242U,
89 0x68ddb3f8U, 0x1fda836eU, 0x81be16cdU, 0xf6b9265bU, 0x6fb077e1U,
90 0x18b74777U, 0x88085ae6U, 0xff0f6a70U, 0x66063bcaU, 0x11010b5cU,
91 0x8f659effU, 0xf862ae69U, 0x616bffd3U, 0x166ccf45U, 0xa00ae278U,
92 0xd70dd2eeU, 0x4e048354U, 0x3903b3c2U, 0xa7672661U, 0xd06016f7U,
93 0x4969474dU, 0x3e6e77dbU, 0xaed16a4aU, 0xd9d65adcU, 0x40df0b66U,
94 0x37d83bf0U, 0xa9bcae53U, 0xdebb9ec5U, 0x47b2cf7fU, 0x30b5ffe9U,
95 0xbdbdf21cU, 0xcabac28aU, 0x53b39330U, 0x24b4a3a6U, 0xbad03605U,
96 0xcdd70693U, 0x54de5729U, 0x23d967bfU, 0xb3667a2eU, 0xc4614ab8U,
97 0x5d681b02U, 0x2a6f2b94U, 0xb40bbe37U, 0xc30c8ea1U, 0x5a05df1bU,
98 0x2d02ef8dU
Louis Yung-Chieh Lo49fa8e52010-04-30 16:10:48 -070099};
100
Louis Yung-Chieh Lo49fa8e52010-04-30 16:10:48 -0700101
Randall Spanglercefe12c2013-01-30 12:52:02 -0800102uint32_t Crc32(const void *buffer, uint32_t len)
103{
104 uint8_t *byte = (uint8_t *)buffer;
105 uint32_t i;
106 uint32_t value = ~0U;
107
108 for (i = 0; i < len; ++i)
109 value = crc32_tab[(value ^ byte[i]) & 0xff] ^ (value >> 8);
110 return value ^ ~0U;
Louis Yung-Chieh Lo49fa8e52010-04-30 16:10:48 -0700111}