MOV CX,5 
  MOV BX,OFFSET ASC 
  MOV DI,OFFSET UNPACK 
AGAIN: MOV AX,WORD PTR [BX] 
  AND AX,0F0FH 
  MOV WORD PTR [DI],AX 
  ADD DI,2 
  ADD BX,2 
  LOOP AGAIN