def crc16_nojit(s, crc=<NUM_LIT:0>):
for ch in bytearray(s):  <EOL><INDENT>crc = ((crc << <NUM_LIT:8>) & <NUM_LIT>) ^ _crc16_tab[((crc >> <NUM_LIT:8>) & <NUM_LIT>) ^ (ch & <NUM_LIT>)]<EOL>crc &= <NUM_LIT><EOL><DEDENT>return crc<EOL>
CRC16 implementation acording to CCITT standards.