Int64Rec declares a utility record to provide access to the bytes of an Int64 value.

Int64Rec = packed record
  case Integer of
    0: (Hi: Cardinal;
        Lo: Cardinal;);
    1: (Cardinals: array [0..1] of Cardinal);
        Words: array [0..3] of Word);
        Bytes: array [0..7] of Byte););
end;

struct Int64Rec {
  unsigned Hi;
  unsigned Lo;
  array [0..1] of Cardinal) Cardinals;
  array [0..3] of Word) Words;
  array [0..7] of Byte) Bytes;
};