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  Title:    Input from Port                       Flags: O D I T S Z A P C
                                                         ═════════════════
  Syntax:   IN accumulator,port                               -none-
 
  See also: OUT, INS, OUTS
 
  Description:
 
     Transfers a byte or word (or doubleword on the 80386/486) from a
     port to the accumulator register. The port address is specified by
     the source operand, which can be DX or an 8-bit constant.
 
     Constants can only be used for port numbers less than 255; use DX
     for higher port numbers.
 
     In protected mode, a general-protection fault occurs if IN is used
     when the current privilege level is greater than the value of the
     IOPL flag.
                                    -♦-