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  Port[portnum]
  PortW[portnum]
 
  Unit:      System (used automatically)
 
  See also:  Mem, MemW, MemL
 
  Description
 
    Two predefined arrays are available for accessing ports directly.
    Port accesses bytes and PortW accesses words. The port number
    is specified as the array index. The entire Port or PortW arrays
    cannot be used. Single elements of the arrays can be used in
    assignments and references, but not as variable parameters.
    Using ports is an advanced and potentially dangerous technique
    that should be used with care.
 
    Some examples are shown below:
 
       { Read byte from port $64 }
       PortRead := Port[$64];
 
       { Write word to port $B6  }
       PortW[$B6] := $1120;