  MOV SI,OFFSET ITSOFF
  MOV DI,080
  MOV CX,4
  REPE CMPSB
  JE >L1
  MOV SI,OFFSET ITSON
  MOV DI,080
  MOV CX,3
  REPE CMPSB
  JE >L2
  MOV DX,OFFSET INSTRUCT
  JMP SHORT >L3
L1:
  MOV DX,03FA
  MOV AL,0
  OUT DX,AL
  MOV DX,OFFSET UART1
  JMP SHORT >L3
L2:
  MOV DX,03FA
  MOV AL,11000001xB
  OUT DX,AL
  JMP SHORT $+2
  IN AL,DX
  MOV DX,OFFSET UART2
  AND AL,11000000xB
  CMP AL,11000000xB
  JE >L3
  MOV DX,OFFSET UART3
L3:
  MOV AH,9
  INT 021
  INT 020
INSTRUCT DB 'TYPE "UARTBUF ON" OR "UARTBUF OFF" TO ENABLE OR DISABLE'
	 DB ' 16550A UART BUFFER$'
ITSOFF DB 4,' OFF'
ITSON DB 3,' ON'
UART1 DB '16550A UART BUFFER DISABLED$'
UART2 DB '16550A UART BUFFER ENABLED$'
UART3 DB "YOU DON'T HAVE A 16550A UART$"

