Initial import

git-svn-id: http://moon:8086/svn/software/trunk/libsrc/crc@1 b431acfa-c32f-4a4a-93f1-934dc6c82436
2014-07-19 07:44:42 +00:00
commit ec11499cb4
2 changed files with 65 additions and 0 deletions
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+/* CRC16.C */
+
+/* Developed 1990-1997 by Rob Swindell; PO Box 501, Yorba Linda, CA 92885 */
+
+/* 16-bit CRC routines */
+
+#include <stdint.h>
+
+/****************************************************************************/
+/* Updates 16-bit "rcrc" with character 'ch'                                */
+/****************************************************************************/
+uint16_t Upd_crc16(uint8_t ch, uint16_t poly, uint16_t crc)
+{
+	uint16_t i, cy;
+	uint8_t nch = ch;
+ 
+	for (i=0; i<8; i++)
+	{
+		cy = crc & 0x8000;
+		crc <<= 1;
+		if (nch & 0x80)
+			crc |= 1;
+		
+		nch<<=1;
+		
+		if (cy) 
+			crc ^= poly;
+	}
+	return crc;
+}
+
+/****************************************************************************/
+/* Returns 16-crc of string (not counting terminating NULL)                 */
+/****************************************************************************/
+uint16_t Crc16(uint16_t poly, uint16_t crc, uint8_t *pBuf, uint32_t len)
+{
+	while(len)
+	{
+		crc = Upd_crc16(*pBuf, poly, crc);
+		pBuf++;
+		len--;
+
+	}
+
+	return crc;
+}