OUTSB             Output Byte String (186/286/386) Flags: O D I T S Z A P C

OUTSB

           Logic:          destination port . BYTE PTR ES:DI
                           if DF = 0 then
                               DI . DI + 1
                           else
                               DI . DI - 1

     This instruction sends bytes from a string to a port. The source string
     is pointed to by ES:DI. The input port number must be in DX. If the
     direction flag is set, DI is decremented. If it is not set, DI is
     incremented.

  --------------------------------------------------------------------------
   Operands                   Clocks   Transfers  Bytes  Example
   OUTSB                      5 (286)      -        1    OUTSB
  --------------------------------------------------------------------------

        Note:          This instruction is usually used with a REP
                       prefix. Load CX with the number of times to repeat
                       the instruction.