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1 | //========================================================================== |
2 | // | |
3 | // crc16.c | |
4 | // | |
5 | // 16 bit CRC with polynomial x^16+x^12+x^5+1 | |
6 | // | |
7 | //========================================================================== | |
8 | //####ECOSGPLCOPYRIGHTBEGIN#### | |
9 | // ------------------------------------------- | |
10 | // This file is part of eCos, the Embedded Configurable Operating System. | |
11 | // Copyright (C) 1998, 1999, 2000, 2001, 2002 Red Hat, Inc. | |
12 | // Copyright (C) 2002 Gary Thomas | |
13 | // | |
14 | // eCos is free software; you can redistribute it and/or modify it under | |
15 | // the terms of the GNU General Public License as published by the Free | |
16 | // Software Foundation; either version 2 or (at your option) any later version. | |
17 | // | |
18 | // eCos is distributed in the hope that it will be useful, but WITHOUT ANY | |
19 | // WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
20 | // FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
21 | // for more details. | |
22 | // | |
23 | // You should have received a copy of the GNU General Public License along | |
24 | // with eCos; if not, write to the Free Software Foundation, Inc., | |
25 | // 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. | |
26 | // | |
27 | // As a special exception, if other files instantiate templates or use macros | |
28 | // or inline functions from this file, or you compile this file and link it | |
29 | // with other works to produce a work based on this file, this file does not | |
30 | // by itself cause the resulting work to be covered by the GNU General Public | |
31 | // License. However the source code for this file must still be made available | |
32 | // in accordance with section (3) of the GNU General Public License. | |
33 | // | |
34 | // This exception does not invalidate any other reasons why a work based on | |
35 | // this file might be covered by the GNU General Public License. | |
36 | // | |
37 | // Alternative licenses for eCos may be arranged by contacting Red Hat, Inc. | |
38 | // at http://sources.redhat.com/ecos/ecos-license/ | |
39 | // ------------------------------------------- | |
40 | //####ECOSGPLCOPYRIGHTEND#### | |
41 | //========================================================================== | |
42 | //#####DESCRIPTIONBEGIN#### | |
43 | // | |
44 | // Author(s): gthomas | |
45 | // Contributors: gthomas,asl | |
46 | // Date: 2001-01-31 | |
47 | // Purpose: | |
48 | // Description: | |
49 | // | |
50 | // This code is part of eCos (tm). | |
51 | // | |
52 | //####DESCRIPTIONEND#### | |
53 | // | |
54 | //========================================================================== | |
55 | ||
56 | #include "crc.h" | |
57 | ||
58 | // Table of CRC constants - implements x^16+x^12+x^5+1 | |
59 | static const uint16_t crc16_tab[] = { | |
60 | 0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50a5, 0x60c6, 0x70e7, | |
61 | 0x8108, 0x9129, 0xa14a, 0xb16b, 0xc18c, 0xd1ad, 0xe1ce, 0xf1ef, | |
62 | 0x1231, 0x0210, 0x3273, 0x2252, 0x52b5, 0x4294, 0x72f7, 0x62d6, | |
63 | 0x9339, 0x8318, 0xb37b, 0xa35a, 0xd3bd, 0xc39c, 0xf3ff, 0xe3de, | |
64 | 0x2462, 0x3443, 0x0420, 0x1401, 0x64e6, 0x74c7, 0x44a4, 0x5485, | |
65 | 0xa56a, 0xb54b, 0x8528, 0x9509, 0xe5ee, 0xf5cf, 0xc5ac, 0xd58d, | |
66 | 0x3653, 0x2672, 0x1611, 0x0630, 0x76d7, 0x66f6, 0x5695, 0x46b4, | |
67 | 0xb75b, 0xa77a, 0x9719, 0x8738, 0xf7df, 0xe7fe, 0xd79d, 0xc7bc, | |
68 | 0x48c4, 0x58e5, 0x6886, 0x78a7, 0x0840, 0x1861, 0x2802, 0x3823, | |
69 | 0xc9cc, 0xd9ed, 0xe98e, 0xf9af, 0x8948, 0x9969, 0xa90a, 0xb92b, | |
70 | 0x5af5, 0x4ad4, 0x7ab7, 0x6a96, 0x1a71, 0x0a50, 0x3a33, 0x2a12, | |
71 | 0xdbfd, 0xcbdc, 0xfbbf, 0xeb9e, 0x9b79, 0x8b58, 0xbb3b, 0xab1a, | |
72 | 0x6ca6, 0x7c87, 0x4ce4, 0x5cc5, 0x2c22, 0x3c03, 0x0c60, 0x1c41, | |
73 | 0xedae, 0xfd8f, 0xcdec, 0xddcd, 0xad2a, 0xbd0b, 0x8d68, 0x9d49, | |
74 | 0x7e97, 0x6eb6, 0x5ed5, 0x4ef4, 0x3e13, 0x2e32, 0x1e51, 0x0e70, | |
75 | 0xff9f, 0xefbe, 0xdfdd, 0xcffc, 0xbf1b, 0xaf3a, 0x9f59, 0x8f78, | |
76 | 0x9188, 0x81a9, 0xb1ca, 0xa1eb, 0xd10c, 0xc12d, 0xf14e, 0xe16f, | |
77 | 0x1080, 0x00a1, 0x30c2, 0x20e3, 0x5004, 0x4025, 0x7046, 0x6067, | |
78 | 0x83b9, 0x9398, 0xa3fb, 0xb3da, 0xc33d, 0xd31c, 0xe37f, 0xf35e, | |
79 | 0x02b1, 0x1290, 0x22f3, 0x32d2, 0x4235, 0x5214, 0x6277, 0x7256, | |
80 | 0xb5ea, 0xa5cb, 0x95a8, 0x8589, 0xf56e, 0xe54f, 0xd52c, 0xc50d, | |
81 | 0x34e2, 0x24c3, 0x14a0, 0x0481, 0x7466, 0x6447, 0x5424, 0x4405, | |
82 | 0xa7db, 0xb7fa, 0x8799, 0x97b8, 0xe75f, 0xf77e, 0xc71d, 0xd73c, | |
83 | 0x26d3, 0x36f2, 0x0691, 0x16b0, 0x6657, 0x7676, 0x4615, 0x5634, | |
84 | 0xd94c, 0xc96d, 0xf90e, 0xe92f, 0x99c8, 0x89e9, 0xb98a, 0xa9ab, | |
85 | 0x5844, 0x4865, 0x7806, 0x6827, 0x18c0, 0x08e1, 0x3882, 0x28a3, | |
86 | 0xcb7d, 0xdb5c, 0xeb3f, 0xfb1e, 0x8bf9, 0x9bd8, 0xabbb, 0xbb9a, | |
87 | 0x4a75, 0x5a54, 0x6a37, 0x7a16, 0x0af1, 0x1ad0, 0x2ab3, 0x3a92, | |
88 | 0xfd2e, 0xed0f, 0xdd6c, 0xcd4d, 0xbdaa, 0xad8b, 0x9de8, 0x8dc9, | |
89 | 0x7c26, 0x6c07, 0x5c64, 0x4c45, 0x3ca2, 0x2c83, 0x1ce0, 0x0cc1, | |
90 | 0xef1f, 0xff3e, 0xcf5d, 0xdf7c, 0xaf9b, 0xbfba, 0x8fd9, 0x9ff8, | |
91 | 0x6e17, 0x7e36, 0x4e55, 0x5e74, 0x2e93, 0x3eb2, 0x0ed1, 0x1ef0, | |
92 | }; | |
93 | ||
94 | uint16_t | |
95 | cyg_crc16(unsigned char *buf, int len) | |
96 | { | |
97 | int i; | |
98 | uint16_t cksum; | |
99 | ||
100 | cksum = 0; | |
101 | for (i = 0; i < len; i++) { | |
102 | cksum = crc16_tab[((cksum>>8) ^ *buf++) & 0xFF] ^ (cksum << 8); | |
103 | } | |
104 | return cksum; | |
105 | } | |
106 |