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Wolfgang Denkcf48eb92006-04-16 10:51:58 +02001/*
2 *==========================================================================
3 *
4 * crc16.c
5 *
6 * 16 bit CRC with polynomial x^16+x^12+x^5+1
7 *
8 *==========================================================================
9 *####ECOSGPLCOPYRIGHTBEGIN####
10 * -------------------------------------------
11 * This file is part of eCos, the Embedded Configurable Operating System.
12 * Copyright (C) 1998, 1999, 2000, 2001, 2002 Red Hat, Inc.
13 * Copyright (C) 2002 Gary Thomas
14 *
15 * eCos is free software; you can redistribute it and/or modify it under
16 * the terms of the GNU General Public License as published by the Free
17 * Software Foundation; either version 2 or (at your option) any later version.
18 *
19 * eCos is distributed in the hope that it will be useful, but WITHOUT ANY
20 * WARRANTY; without even the implied warranty of MERCHANTABILITY or
21 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
22 * for more details.
23 *
24 * You should have received a copy of the GNU General Public License along
25 * with eCos; if not, write to the Free Software Foundation, Inc.,
26 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
27 *
28 * As a special exception, if other files instantiate templates or use macros
29 * or inline functions from this file, or you compile this file and link it
30 * with other works to produce a work based on this file, this file does not
31 * by itself cause the resulting work to be covered by the GNU General Public
32 * License. However the source code for this file must still be made available
33 * in accordance with section (3) of the GNU General Public License.
34 *
35 * This exception does not invalidate any other reasons why a work based on
36 * this file might be covered by the GNU General Public License.
37 *
38 * Alternative licenses for eCos may be arranged by contacting Red Hat, Inc.
39 * at http: *sources.redhat.com/ecos/ecos-license/
40 * -------------------------------------------
41 *####ECOSGPLCOPYRIGHTEND####
42 *==========================================================================
43 *#####DESCRIPTIONBEGIN####
44 *
45 * Author(s): gthomas
46 * Contributors: gthomas,asl
47 * Date: 2001-01-31
48 * Purpose:
49 * Description:
50 *
51 * This code is part of eCos (tm).
52 *
53 *####DESCRIPTIONEND####
54 *
55 *==========================================================================
56 */
Markus Klotzbuecherf2841d32006-03-30 13:40:55 +020057
58#include "crc.h"
59
Wolfgang Denkcf48eb92006-04-16 10:51:58 +020060/* Table of CRC constants - implements x^16+x^12+x^5+1 */
Markus Klotzbuecherf2841d32006-03-30 13:40:55 +020061static const uint16_t crc16_tab[] = {
Wolfgang Denkcf48eb92006-04-16 10:51:58 +020062 0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50a5, 0x60c6, 0x70e7,
63 0x8108, 0x9129, 0xa14a, 0xb16b, 0xc18c, 0xd1ad, 0xe1ce, 0xf1ef,
64 0x1231, 0x0210, 0x3273, 0x2252, 0x52b5, 0x4294, 0x72f7, 0x62d6,
65 0x9339, 0x8318, 0xb37b, 0xa35a, 0xd3bd, 0xc39c, 0xf3ff, 0xe3de,
66 0x2462, 0x3443, 0x0420, 0x1401, 0x64e6, 0x74c7, 0x44a4, 0x5485,
67 0xa56a, 0xb54b, 0x8528, 0x9509, 0xe5ee, 0xf5cf, 0xc5ac, 0xd58d,
68 0x3653, 0x2672, 0x1611, 0x0630, 0x76d7, 0x66f6, 0x5695, 0x46b4,
69 0xb75b, 0xa77a, 0x9719, 0x8738, 0xf7df, 0xe7fe, 0xd79d, 0xc7bc,
70 0x48c4, 0x58e5, 0x6886, 0x78a7, 0x0840, 0x1861, 0x2802, 0x3823,
71 0xc9cc, 0xd9ed, 0xe98e, 0xf9af, 0x8948, 0x9969, 0xa90a, 0xb92b,
72 0x5af5, 0x4ad4, 0x7ab7, 0x6a96, 0x1a71, 0x0a50, 0x3a33, 0x2a12,
73 0xdbfd, 0xcbdc, 0xfbbf, 0xeb9e, 0x9b79, 0x8b58, 0xbb3b, 0xab1a,
74 0x6ca6, 0x7c87, 0x4ce4, 0x5cc5, 0x2c22, 0x3c03, 0x0c60, 0x1c41,
75 0xedae, 0xfd8f, 0xcdec, 0xddcd, 0xad2a, 0xbd0b, 0x8d68, 0x9d49,
76 0x7e97, 0x6eb6, 0x5ed5, 0x4ef4, 0x3e13, 0x2e32, 0x1e51, 0x0e70,
77 0xff9f, 0xefbe, 0xdfdd, 0xcffc, 0xbf1b, 0xaf3a, 0x9f59, 0x8f78,
78 0x9188, 0x81a9, 0xb1ca, 0xa1eb, 0xd10c, 0xc12d, 0xf14e, 0xe16f,
79 0x1080, 0x00a1, 0x30c2, 0x20e3, 0x5004, 0x4025, 0x7046, 0x6067,
80 0x83b9, 0x9398, 0xa3fb, 0xb3da, 0xc33d, 0xd31c, 0xe37f, 0xf35e,
81 0x02b1, 0x1290, 0x22f3, 0x32d2, 0x4235, 0x5214, 0x6277, 0x7256,
82 0xb5ea, 0xa5cb, 0x95a8, 0x8589, 0xf56e, 0xe54f, 0xd52c, 0xc50d,
83 0x34e2, 0x24c3, 0x14a0, 0x0481, 0x7466, 0x6447, 0x5424, 0x4405,
84 0xa7db, 0xb7fa, 0x8799, 0x97b8, 0xe75f, 0xf77e, 0xc71d, 0xd73c,
85 0x26d3, 0x36f2, 0x0691, 0x16b0, 0x6657, 0x7676, 0x4615, 0x5634,
86 0xd94c, 0xc96d, 0xf90e, 0xe92f, 0x99c8, 0x89e9, 0xb98a, 0xa9ab,
87 0x5844, 0x4865, 0x7806, 0x6827, 0x18c0, 0x08e1, 0x3882, 0x28a3,
88 0xcb7d, 0xdb5c, 0xeb3f, 0xfb1e, 0x8bf9, 0x9bd8, 0xabbb, 0xbb9a,
89 0x4a75, 0x5a54, 0x6a37, 0x7a16, 0x0af1, 0x1ad0, 0x2ab3, 0x3a92,
90 0xfd2e, 0xed0f, 0xdd6c, 0xcd4d, 0xbdaa, 0xad8b, 0x9de8, 0x8dc9,
91 0x7c26, 0x6c07, 0x5c64, 0x4c45, 0x3ca2, 0x2c83, 0x1ce0, 0x0cc1,
92 0xef1f, 0xff3e, 0xcf5d, 0xdf7c, 0xaf9b, 0xbfba, 0x8fd9, 0x9ff8,
93 0x6e17, 0x7e36, 0x4e55, 0x5e74, 0x2e93, 0x3eb2, 0x0ed1, 0x1ef0,
Markus Klotzbuecherf2841d32006-03-30 13:40:55 +020094};
95
96uint16_t
97cyg_crc16(unsigned char *buf, int len)
98{
99 int i;
100 uint16_t cksum;
101
102 cksum = 0;
103 for (i = 0; i < len; i++) {
104 cksum = crc16_tab[((cksum>>8) ^ *buf++) & 0xFF] ^ (cksum << 8);
105 }
106 return cksum;
107}