archive MK1 AVR source

mk1-src/crc16.c

@@ -0,0 +1,51 @@
+/**
+ * \file stdout
+ * Functions and types for CRC checks.
+ *
+ * Generated on Tue Jun 30 23:02:59 2009,
+ * by pycrc v0.7.1, http://www.tty1.net/pycrc/
+ * using the configuration:
+ *    Width        = 16
+ *    Poly         = 0x8005
+ *    XorIn        = 0x0000
+ *    ReflectIn    = True
+ *    XorOut       = 0x0000
+ *    ReflectOut   = True
+ *    Algorithm    = bit-by-bit-fast
+ *    Direct       = True
+ *****************************************************************************/
+#include <stdint.h>
+#include "crc16.h"
+/**
+ * Update the crc value with new data.
+ *
+ * \param crc      The current crc value.
+ * \param data     Pointer to a buffer of \a data_len bytes.
+ * \param data_len Number of bytes in the \a data buffer.
+ * \return         The updated crc value.
+ *****************************************************************************/
+crc_t crc16_update(crc_t crc, const unsigned char *data, size_t data_len)
+{
+    unsigned int i;
+    uint8_t bit;
+    unsigned char c;
+
+    while (data_len--) {
+        c = *data++;
+        for (i = 0x01; i & 0xff; i <<= 1) {
+            bit = (crc & 0x8000 ? 1 : 0);
+            if (c & i) {
+                bit ^= 1;
+            }
+            crc <<= 1;
+            if (bit) {
+                crc ^= 0x8005;
+            }
+        }
+        crc &= 0xffff;
+    }
+    return crc & 0xffff;
+}
+
+
+