10DIM buff 39
   20OSCLI("LOAD zzz "+STR$~(buff))
   30redcode=0
   40FOR I%=3 TO 37
   50 PROCcrc(buff?I%)
   60NEXT
   70PRINT~redcode;
   80PRINT" = ";~((buff?38)*256+(buff?39));" ?"
   90END
  100DEFPROCcrc(Y)
  110X0=redcode
  120X4=redcode*16
  130X7=redcode*128
  140X9=redcode*512
  150crclow=(((X0 EOR X4 EOR X7 EOR X9) DIV 256) EOR Y) MOD 256
  160topbit = (crclow DIV 128) AND 1
  170crclow = crclow EOR topbit
  180crchigh = redcode MOD 256
  190redcode=crclow + (crchigh*256)
  200PRINT~redcode
  210ENDPROC