VSI Pascal provides another extended integer convention only for
  the   sake  of  compatibility  with  previous  versions  of  the
  language.  This notation specifies an unsigned integer in either
  binary  (base  2),  octal  (base  8),  or  hexadecimal (base 16)
  notation.

  Syntax:
                   b
     [[ + | - ]] % o [[']]extended-digit[[']]
                   x

  The 'b', 'o', or 'x' specifies  binary,  octal,  or  hexidecimal
  notation, respectively.

  The 'extended-digit' specifies the notation that is  appropriate
  for the specified base.

  The following are unsigned integer  values  in  the  VSI  Pascal
  specific notation:

     %x'8000 0000'
     %x'FFFF FFFF'