PORT                      Byte Access to I/O Ports                   pp 206

 Syntax:  Port [ByteIndex]

 Type:    Byte

 Form:    Function or Procedure

 Purpose: Read from or Write to I/O Ports 0..255.

 Notes:   The Port array is pre-defined as   Port : Array [0..255] of Byte ;


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 Usage:
       VAR
          ByteVar    : Byte        ;  { Declare a byte variable   }

       BEGIN
          ByteVar    := Port [$60] ;  { Read from port 60h        }
          Port [$61] := $20        ;  { Write a value to port 61h }
       END.