More versatile CRC function ... planned for auth

ROM2/xmodem.c

@@ -53,17 +53,17 @@ readchar (int timeout)
 }
 
 /* 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)
+docrc (unsigned char *p, int len, bool pad)
 {
   int len2 = len;
   unsigned short crc = 0;
 
   while (len-- > 0)
     crc = (crc << 8) ^ crctab[(crc >> 8) ^ *p++];
-  if (len2 < 128) {
+  if (pad && len2 < 128) {
     len = 128-len;
     while (len-- > 0)
       crc = (crc << 8) ^ crctab[(crc >> 8) ^ 0x1a];
@@ -162,7 +162,7 @@ xmodem_send_packet (const unsigned char *packet, int len)
     if (crcflag) {
       u16 crc;
 
-      crc = docrc ((unsigned char*)packet, len);
+      crc = docrc ((unsigned char*)packet, len, 1);
 
       s[0] = crc >> 8;
       s[1] = crc & 0xff;