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1 //========================================================================== |
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2 // |
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3 // crc16.c |
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4 // |
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5 // 16 bit CRC with polynomial x^16+x^12+x^5+1 |
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6 // |
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7 //========================================================================== |
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8 //####ECOSGPLCOPYRIGHTBEGIN#### |
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9 // ------------------------------------------- |
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10 // This file is part of eCos, the Embedded Configurable Operating System. |
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11 // Copyright (C) 1998, 1999, 2000, 2001, 2002 Red Hat, Inc. |
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12 // Copyright (C) 2002 Gary Thomas |
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13 // |
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14 // eCos is free software; you can redistribute it and/or modify it under |
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15 // the terms of the GNU General Public License as published by the Free |
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16 // Software Foundation; either version 2 or (at your option) any later version. |
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17 // |
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18 // eCos is distributed in the hope that it will be useful, but WITHOUT ANY |
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19 // WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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20 // FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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21 // for more details. |
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22 // |
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23 // You should have received a copy of the GNU General Public License along |
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24 // with eCos; if not, write to the Free Software Foundation, Inc., |
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25 // 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. |
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26 // |
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27 // As a special exception, if other files instantiate templates or use macros |
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28 // or inline functions from this file, or you compile this file and link it |
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29 // with other works to produce a work based on this file, this file does not |
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30 // by itself cause the resulting work to be covered by the GNU General Public |
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31 // License. However the source code for this file must still be made available |
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32 // in accordance with section (3) of the GNU General Public License. |
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33 // |
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34 // This exception does not invalidate any other reasons why a work based on |
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35 // this file might be covered by the GNU General Public License. |
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36 // |
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37 // Alternative licenses for eCos may be arranged by contacting Red Hat, Inc. |
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38 // at http://sources.redhat.com/ecos/ecos-license/ |
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39 // ------------------------------------------- |
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40 //####ECOSGPLCOPYRIGHTEND#### |
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41 //========================================================================== |
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42 //#####DESCRIPTIONBEGIN#### |
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43 // |
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44 // Author(s): gthomas |
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45 // Contributors: gthomas,asl |
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46 // Date: 2001-01-31 |
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47 // Purpose: |
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48 // Description: |
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49 // |
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50 // This code is part of eCos (tm). |
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51 // |
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52 //####DESCRIPTIONEND#### |
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53 // |
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54 //========================================================================== |
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55 |
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56 #include <cyg/crc/crc.h> |
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57 |
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58 // Table of CRC constants - implements x^16+x^12+x^5+1 |
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59 static const cyg_uint16 crc16_tab[] = { |
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60 0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50a5, 0x60c6, 0x70e7, |
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61 0x8108, 0x9129, 0xa14a, 0xb16b, 0xc18c, 0xd1ad, 0xe1ce, 0xf1ef, |
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62 0x1231, 0x0210, 0x3273, 0x2252, 0x52b5, 0x4294, 0x72f7, 0x62d6, |
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63 0x9339, 0x8318, 0xb37b, 0xa35a, 0xd3bd, 0xc39c, 0xf3ff, 0xe3de, |
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64 0x2462, 0x3443, 0x0420, 0x1401, 0x64e6, 0x74c7, 0x44a4, 0x5485, |
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65 0xa56a, 0xb54b, 0x8528, 0x9509, 0xe5ee, 0xf5cf, 0xc5ac, 0xd58d, |
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66 0x3653, 0x2672, 0x1611, 0x0630, 0x76d7, 0x66f6, 0x5695, 0x46b4, |
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67 0xb75b, 0xa77a, 0x9719, 0x8738, 0xf7df, 0xe7fe, 0xd79d, 0xc7bc, |
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68 0x48c4, 0x58e5, 0x6886, 0x78a7, 0x0840, 0x1861, 0x2802, 0x3823, |
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69 0xc9cc, 0xd9ed, 0xe98e, 0xf9af, 0x8948, 0x9969, 0xa90a, 0xb92b, |
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70 0x5af5, 0x4ad4, 0x7ab7, 0x6a96, 0x1a71, 0x0a50, 0x3a33, 0x2a12, |
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71 0xdbfd, 0xcbdc, 0xfbbf, 0xeb9e, 0x9b79, 0x8b58, 0xbb3b, 0xab1a, |
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72 0x6ca6, 0x7c87, 0x4ce4, 0x5cc5, 0x2c22, 0x3c03, 0x0c60, 0x1c41, |
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73 0xedae, 0xfd8f, 0xcdec, 0xddcd, 0xad2a, 0xbd0b, 0x8d68, 0x9d49, |
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74 0x7e97, 0x6eb6, 0x5ed5, 0x4ef4, 0x3e13, 0x2e32, 0x1e51, 0x0e70, |
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75 0xff9f, 0xefbe, 0xdfdd, 0xcffc, 0xbf1b, 0xaf3a, 0x9f59, 0x8f78, |
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76 0x9188, 0x81a9, 0xb1ca, 0xa1eb, 0xd10c, 0xc12d, 0xf14e, 0xe16f, |
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77 0x1080, 0x00a1, 0x30c2, 0x20e3, 0x5004, 0x4025, 0x7046, 0x6067, |
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78 0x83b9, 0x9398, 0xa3fb, 0xb3da, 0xc33d, 0xd31c, 0xe37f, 0xf35e, |
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79 0x02b1, 0x1290, 0x22f3, 0x32d2, 0x4235, 0x5214, 0x6277, 0x7256, |
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80 0xb5ea, 0xa5cb, 0x95a8, 0x8589, 0xf56e, 0xe54f, 0xd52c, 0xc50d, |
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81 0x34e2, 0x24c3, 0x14a0, 0x0481, 0x7466, 0x6447, 0x5424, 0x4405, |
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82 0xa7db, 0xb7fa, 0x8799, 0x97b8, 0xe75f, 0xf77e, 0xc71d, 0xd73c, |
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83 0x26d3, 0x36f2, 0x0691, 0x16b0, 0x6657, 0x7676, 0x4615, 0x5634, |
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84 0xd94c, 0xc96d, 0xf90e, 0xe92f, 0x99c8, 0x89e9, 0xb98a, 0xa9ab, |
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85 0x5844, 0x4865, 0x7806, 0x6827, 0x18c0, 0x08e1, 0x3882, 0x28a3, |
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86 0xcb7d, 0xdb5c, 0xeb3f, 0xfb1e, 0x8bf9, 0x9bd8, 0xabbb, 0xbb9a, |
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87 0x4a75, 0x5a54, 0x6a37, 0x7a16, 0x0af1, 0x1ad0, 0x2ab3, 0x3a92, |
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88 0xfd2e, 0xed0f, 0xdd6c, 0xcd4d, 0xbdaa, 0xad8b, 0x9de8, 0x8dc9, |
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89 0x7c26, 0x6c07, 0x5c64, 0x4c45, 0x3ca2, 0x2c83, 0x1ce0, 0x0cc1, |
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90 0xef1f, 0xff3e, 0xcf5d, 0xdf7c, 0xaf9b, 0xbfba, 0x8fd9, 0x9ff8, |
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91 0x6e17, 0x7e36, 0x4e55, 0x5e74, 0x2e93, 0x3eb2, 0x0ed1, 0x1ef0, |
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92 }; |
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93 |
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395
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94 cyg_uint16 |
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95 cyg_crc16(unsigned char *buf, int len) |
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96 { |
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97 int i; |
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395
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98 cyg_uint16 cksum; |
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99 |
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100 cksum = 0; |
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101 for (i = 0; i < len; i++) { |
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102 cksum = crc16_tab[((cksum>>8) ^ *buf++) & 0xFF] ^ (cksum << 8); |
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103 } |
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104 return cksum; |
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105 } |
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106 |