231 lines
8.5 KiB
C
231 lines
8.5 KiB
C
/**
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* @file crc16.c
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* @brief Расчёт контрольных сумм CRC-CCITT и CRC-16 для протокольных кадров.
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*
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* Поддерживает табличные и побитовые варианты алгоритмов. Текущая конфигурация
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* FAST_CRC/ONLY_CRC16 оставляет в прошивке только требуемый быстрый CRC-16.
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* Размер задаётся в элементах буфера целевой платформы, а не в байтах host-PC;
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* начальное значение CRC определяет вызывающий протокол.
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*/
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#include "crc16.h"
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#define MAKE_TABS 0 /* Builds tables below */
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#define FAST_CRC 1 /* If fast CRC should be used */
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#define ONLY_CRC16 1
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#define Poln 0xA001
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#if FAST_CRC & !MAKE_TABS
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#if !ONLY_CRC16
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static WORD crc_ccitt_tab[] = {
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0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50a5, 0x60c6, 0x70e7,
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0x8108, 0x9129, 0xa14a, 0xb16b, 0xc18c, 0xd1ad, 0xe1ce, 0xf1ef,
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0x1231, 0x0210, 0x3273, 0x2252, 0x52b5, 0x4294, 0x72f7, 0x62d6,
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0x9339, 0x8318, 0xb37b, 0xa35a, 0xd3bd, 0xc39c, 0xf3ff, 0xe3de,
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0x2462, 0x3443, 0x0420, 0x1401, 0x64e6, 0x74c7, 0x44a4, 0x5485,
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0xa56a, 0xb54b, 0x8528, 0x9509, 0xe5ee, 0xf5cf, 0xc5ac, 0xd58d,
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0x3653, 0x2672, 0x1611, 0x0630, 0x76d7, 0x66f6, 0x5695, 0x46b4,
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0xb75b, 0xa77a, 0x9719, 0x8738, 0xf7df, 0xe7fe, 0xd79d, 0xc7bc,
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0x48c4, 0x58e5, 0x6886, 0x78a7, 0x0840, 0x1861, 0x2802, 0x3823,
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0xc9cc, 0xd9ed, 0xe98e, 0xf9af, 0x8948, 0x9969, 0xa90a, 0xb92b,
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0x5af5, 0x4ad4, 0x7ab7, 0x6a96, 0x1a71, 0x0a50, 0x3a33, 0x2a12,
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0xdbfd, 0xcbdc, 0xfbbf, 0xeb9e, 0x9b79, 0x8b58, 0xbb3b, 0xab1a,
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0x6ca6, 0x7c87, 0x4ce4, 0x5cc5, 0x2c22, 0x3c03, 0x0c60, 0x1c41,
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0xedae, 0xfd8f, 0xcdec, 0xddcd, 0xad2a, 0xbd0b, 0x8d68, 0x9d49,
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0x7e97, 0x6eb6, 0x5ed5, 0x4ef4, 0x3e13, 0x2e32, 0x1e51, 0x0e70,
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0xff9f, 0xefbe, 0xdfdd, 0xcffc, 0xbf1b, 0xaf3a, 0x9f59, 0x8f78,
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0x9188, 0x81a9, 0xb1ca, 0xa1eb, 0xd10c, 0xc12d, 0xf14e, 0xe16f,
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0x1080, 0x00a1, 0x30c2, 0x20e3, 0x5004, 0x4025, 0x7046, 0x6067,
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0x83b9, 0x9398, 0xa3fb, 0xb3da, 0xc33d, 0xd31c, 0xe37f, 0xf35e,
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0x02b1, 0x1290, 0x22f3, 0x32d2, 0x4235, 0x5214, 0x6277, 0x7256,
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0xb5ea, 0xa5cb, 0x95a8, 0x8589, 0xf56e, 0xe54f, 0xd52c, 0xc50d,
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0x34e2, 0x24c3, 0x14a0, 0x0481, 0x7466, 0x6447, 0x5424, 0x4405,
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0xa7db, 0xb7fa, 0x8799, 0x97b8, 0xe75f, 0xf77e, 0xc71d, 0xd73c,
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0x26d3, 0x36f2, 0x0691, 0x16b0, 0x6657, 0x7676, 0x4615, 0x5634,
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0xd94c, 0xc96d, 0xf90e, 0xe92f, 0x99c8, 0x89e9, 0xb98a, 0xa9ab,
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0x5844, 0x4865, 0x7806, 0x6827, 0x18c0, 0x08e1, 0x3882, 0x28a3,
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0xcb7d, 0xdb5c, 0xeb3f, 0xfb1e, 0x8bf9, 0x9bd8, 0xabbb, 0xbb9a,
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0x4a75, 0x5a54, 0x6a37, 0x7a16, 0x0af1, 0x1ad0, 0x2ab3, 0x3a92,
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0xfd2e, 0xed0f, 0xdd6c, 0xcd4d, 0xbdaa, 0xad8b, 0x9de8, 0x8dc9,
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0x7c26, 0x6c07, 0x5c64, 0x4c45, 0x3ca2, 0x2c83, 0x1ce0, 0x0cc1,
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0xef1f, 0xff3e, 0xcf5d, 0xdf7c, 0xaf9b, 0xbfba, 0x8fd9, 0x9ff8,
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0x6e17, 0x7e36, 0x4e55, 0x5e74, 0x2e93, 0x3eb2, 0x0ed1, 0x1ef0
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};
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#endif
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WORD crc_16_tab[] = {
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0x0000, 0xc0c1, 0xc181, 0x0140, 0xc301, 0x03c0, 0x0280, 0xc241,
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0xc601, 0x06c0, 0x0780, 0xc741, 0x0500, 0xc5c1, 0xc481, 0x0440,
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0xcc01, 0x0cc0, 0x0d80, 0xcd41, 0x0f00, 0xcfc1, 0xce81, 0x0e40,
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0x0a00, 0xcac1, 0xcb81, 0x0b40, 0xc901, 0x09c0, 0x0880, 0xc841,
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0xd801, 0x18c0, 0x1980, 0xd941, 0x1b00, 0xdbc1, 0xda81, 0x1a40,
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0x1e00, 0xdec1, 0xdf81, 0x1f40, 0xdd01, 0x1dc0, 0x1c80, 0xdc41,
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0x1400, 0xd4c1, 0xd581, 0x1540, 0xd701, 0x17c0, 0x1680, 0xd641,
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0xd201, 0x12c0, 0x1380, 0xd341, 0x1100, 0xd1c1, 0xd081, 0x1040,
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0xf001, 0x30c0, 0x3180, 0xf141, 0x3300, 0xf3c1, 0xf281, 0x3240,
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0x3600, 0xf6c1, 0xf781, 0x3740, 0xf501, 0x35c0, 0x3480, 0xf441,
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0x3c00, 0xfcc1, 0xfd81, 0x3d40, 0xff01, 0x3fc0, 0x3e80, 0xfe41,
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0xfa01, 0x3ac0, 0x3b80, 0xfb41, 0x3900, 0xf9c1, 0xf881, 0x3840,
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0x2800, 0xe8c1, 0xe981, 0x2940, 0xeb01, 0x2bc0, 0x2a80, 0xea41,
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0xee01, 0x2ec0, 0x2f80, 0xef41, 0x2d00, 0xedc1, 0xec81, 0x2c40,
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0xe401, 0x24c0, 0x2580, 0xe541, 0x2700, 0xe7c1, 0xe681, 0x2640,
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0x2200, 0xe2c1, 0xe381, 0x2340, 0xe101, 0x21c0, 0x2080, 0xe041,
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0xa001, 0x60c0, 0x6180, 0xa141, 0x6300, 0xa3c1, 0xa281, 0x6240,
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0x6600, 0xa6c1, 0xa781, 0x6740, 0xa501, 0x65c0, 0x6480, 0xa441,
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0x6c00, 0xacc1, 0xad81, 0x6d40, 0xaf01, 0x6fc0, 0x6e80, 0xae41,
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0xaa01, 0x6ac0, 0x6b80, 0xab41, 0x6900, 0xa9c1, 0xa881, 0x6840,
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0x7800, 0xb8c1, 0xb981, 0x7940, 0xbb01, 0x7bc0, 0x7a80, 0xba41,
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0xbe01, 0x7ec0, 0x7f80, 0xbf41, 0x7d00, 0xbdc1, 0xbc81, 0x7c40,
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0xb401, 0x74c0, 0x7580, 0xb541, 0x7700, 0xb7c1, 0xb681, 0x7640,
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0x7200, 0xb2c1, 0xb381, 0x7340, 0xb101, 0x71c0, 0x7080, 0xb041,
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0x5000, 0x90c1, 0x9181, 0x5140, 0x9301, 0x53c0, 0x5280, 0x9241,
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0x9601, 0x56c0, 0x5780, 0x9741, 0x5500, 0x95c1, 0x9481, 0x5440,
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0x9c01, 0x5cc0, 0x5d80, 0x9d41, 0x5f00, 0x9fc1, 0x9e81, 0x5e40,
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0x5a00, 0x9ac1, 0x9b81, 0x5b40, 0x9901, 0x59c0, 0x5880, 0x9841,
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0x8801, 0x48c0, 0x4980, 0x8941, 0x4b00, 0x8bc1, 0x8a81, 0x4a40,
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0x4e00, 0x8ec1, 0x8f81, 0x4f40, 0x8d01, 0x4dc0, 0x4c80, 0x8c41,
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0x4400, 0x84c1, 0x8581, 0x4540, 0x8701, 0x47c0, 0x4680, 0x8641,
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0x8201, 0x42c0, 0x4380, 0x8341, 0x4100, 0x81c1, 0x8081, 0x4040
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};
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#endif
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#if !ONLY_CRC16
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/* CRC-CCITT is based on the polynomial x^16 + x^12 + x^5 + 1. Bits */
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/* are sent MSB to LSB. */
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/**
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* @brief Продолжает расчёт CRC-CCITT по массиву слов.
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* @param crc Начальное значение либо CRC предыдущего блока.
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* @param buf Буфер данных; значим младший байт каждого слова.
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* @param size Число обрабатываемых элементов.
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* @return Итоговое 16-битное значение CRC-CCITT.
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*/
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unsigned int get_crc_ccitt(unsigned int crc,unsigned int *buf,unsigned long size )
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{
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#if !(FAST_CRC & !MAKE_TABS)
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register int i;
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#endif
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while (size--) {
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#if FAST_CRC & !MAKE_TABS
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crc = (crc << 8) ^ crc_ccitt_tab[ (crc >> 8) ^ *buf++ ];
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#else
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crc ^= (WORD)(*buf++) << 8;
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for (i = 0; i < 8; i++) {
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if (crc & 0x8000)
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crc = (crc << 1) ^ 0x1021;
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else
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crc <<= 1;
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}
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#endif
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} return crc;
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}
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#endif
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/* CRC-16 is based on the polynomial x^16 + x^15 + x^2 + 1. Bits are */
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/* sent LSB to MSB. */
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/**
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* @brief Вычисляет быстрый табличный CRC-16 с отражённым полиномом 0xA001.
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* @param crc Начальное значение или результат предыдущей порции.
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* @param buf Входные слова протокольного кадра.
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* @param size Количество слов.
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* @return CRC после обработки всего блока.
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*/
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unsigned int get_crc_16(unsigned int crc,unsigned int *buf,unsigned long size )
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{
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#if !(FAST_CRC & !MAKE_TABS)
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register unsigned int i;
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register unsigned int ch;
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#endif
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while (size--) {
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#if FAST_CRC & !MAKE_TABS
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crc = (crc >> 8) ^ crc_16_tab[ (crc ^ *buf++) & 0xff ];
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crc = crc & 0xffff;
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#else
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ch = *buf++;
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for (i = 0; i < 8; i++) {
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if ((crc ^ ch) & 1)
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crc = (crc >> 1) ^ 0xa001;
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else
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crc >>= 1;
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ch >>= 1;
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}
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#endif
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} return (crc & 0xffff);
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}
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/**
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* @brief Побитовый эталон расчёта CRC-16 без таблицы.
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* @details Используется как компактная реализация и для сверки табличного
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* варианта; восемь итераций обрабатывают каждый входной байт.
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*/
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unsigned int get_crc_16b(unsigned int crc,unsigned int *buf,unsigned long size )
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{
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unsigned int x, dword, byte;
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unsigned long i;
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for (i = 0; i < size; i++)
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{
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x = i % 2;
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dword = buf[i/2];
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// dword = *buf;
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if (x == 0)
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{
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byte = ((dword >> 8)&0xFF);
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}
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if (x == 1)
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{
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byte = (dword & 0xFF);
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}
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crc = (crc >> 8) ^ crc_16_tab[ (crc ^ (byte) ) & 0xff ];
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crc = crc & 0xffff;
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// crc = crc + ((byte) & 0xff);
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}
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return (crc & 0xffff);
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}
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/**
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* @brief Проектная обёртка CRC-16 с установленным протоколом начальным значением.
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* @param buf Кадр без добавляемого поля CRC.
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* @param size Число элементов кадра.
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* @return Контрольная сумма, готовая для сравнения или передачи.
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*/
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int get_crc16(unsigned int *buf, int size )
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{
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int crc16,i,j;
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crc16=0xFFFF;
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for(i=0;i<size;i++)
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{
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crc16=crc16^(buf[i]&0xFF);
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for (j=0;j<8;j++)
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if(crc16&1) crc16=(crc16>>1)^Poln;
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else crc16=crc16>>1;
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crc16=crc16^((buf[i]>>8)&0xFF);
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for (j=0;j<8;j++)
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if(crc16&1) crc16=(crc16>>1)^Poln;
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else crc16=crc16>>1;
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}
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return crc16;
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}
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