#include "chime.h"
#include "sci.h"
#include "xmodem.h"
+#include "crctab.h"
/* These definitions are for xmodem protocol. */
return 0;
}
-#define CRC16 0x1021 /* Generator polynomial (X^16 + X^12 + X^5 + 1) */
-
-
-/* Call this to init the fast CRC-16 calculation table. */
-
-static short crctab(u8 val) {
- int i;
- unsigned int crc;
-
- crc = val << 8;
-
- for (i = 0; i < 8; ++i)
- {
- crc <<= 1;
-
- if (crc & 0x10000)
- crc ^= CRC16;
- }
-
- return crc;
-}
-
/* Calculate a CRC-16 for the LEN byte message pointed at by P. */
-/* Pads with ^Z if necessary */
+/* Pads with ^Z up to 128 bytes if told to */
-static unsigned short
-docrc (unsigned char *p, int len)
+unsigned short
+docrc (unsigned char *p, short len, bool pad, unsigned short crc)
{
- int len2 = len;
- unsigned short crc = 0;
+ short len2 = len;
- while (len-- > 0)
- crc = (crc << 8) ^ crctab((crc >> 8) ^ *p++);
- if (len2 < 128) {
+ while (len-- > 0) {
+ crc = (crc << 8) ^ (crctab[(crc >> 8) ^ *p]);
+ p++;
+ }
+ if (pad && len2 < 128) {
len = 128-len;
while (len-- > 0)
- crc = (crc << 8) ^ crctab((crc >> 8) ^ 0x1a);
+ crc = (crc << 8) ^ crctab[(crc >> 8) ^ 0x1a];
}
return crc;
if (crcflag) {
u16 crc;
- crc = docrc ((unsigned char*)packet, len);
+ crc = docrc ((unsigned char*)packet, len, 1, 0);
s[0] = crc >> 8;
s[1] = crc & 0xff;