int array checksum

COMMON DEF CHKSUM_IDAT(ARRAY%)
 VAR SUM%, I%, J%, V%, O%
 FOR I% = 0 TO LEN(ARRAY%) - 1
  FOR J% = 3 TO 0 STEP -1
   O% = J% * 8
   V% = (ARRAY[I%] AND (&HFF << O%)) >> O%
   SUM% = SUM% + V% AND &HFFFF
  NEXT
 NEXT
 RETURN SUM%
END