The big-endian and little-endian format simply swaps the HiByte and LoBytes and HiWords and LoWords of a given integer or word value. The following demonstrates swapping the values of a given word or longint. Calling the Endian functions a second time reverts the values back to their original format.

function EndianWord(w : word) : word;
begin
  result := swap(w);
end;
function EndianInt(i : integer) : integer;
begin
  result := swap(i);
end;
function EndianLong(L : longint) : longint;
begin
  result := swap(L shr  6) or
           (longint(swap(L and $ffff)) shl  6);
end;
procedure TForm .Button Click(Sender: TObject);
var
  w : word;
  i : integer;
  l : LongInt;
begin
  w :=  0;
  i := - 0;
  l :=  024;
  w := EndianWord(w);
  i := EndianInt(i);
  l := EndianLong(l);
 {again!}
  w := EndianWord(w);
  i := EndianInt(i);
  l := EndianLong(l);
  Memo .Lines.Add(IntToStr(w));
  Memo .Lines.Add(IntToStr(i));
  Memo .Lines.Add(IntToStr(l));
end;