jens
ec11499cb4
git-svn-id: http://moon:8086/svn/software/trunk/libsrc/crc@1 b431acfa-c32f-4a4a-93f1-934dc6c82436
47 lines
1.1 KiB
C
Executable File
47 lines
1.1 KiB
C
Executable File
/* CRC16.C */
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/* Developed 1990-1997 by Rob Swindell; PO Box 501, Yorba Linda, CA 92885 */
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/* 16-bit CRC routines */
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#include <stdint.h>
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/****************************************************************************/
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/* Updates 16-bit "rcrc" with character 'ch' */
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/****************************************************************************/
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uint16_t Upd_crc16(uint8_t ch, uint16_t poly, uint16_t crc)
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{
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uint16_t i, cy;
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uint8_t nch = ch;
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for (i=0; i<8; i++)
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{
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cy = crc & 0x8000;
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crc <<= 1;
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if (nch & 0x80)
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crc |= 1;
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nch<<=1;
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if (cy)
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crc ^= poly;
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}
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return crc;
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}
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/****************************************************************************/
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/* Returns 16-crc of string (not counting terminating NULL) */
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/****************************************************************************/
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uint16_t Crc16(uint16_t poly, uint16_t crc, uint8_t *pBuf, uint32_t len)
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{
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while(len)
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{
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crc = Upd_crc16(*pBuf, poly, crc);
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pBuf++;
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len--;
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}
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return crc;
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}
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