procedure TForm1.Button1Click(Sender: TObject);
var wparam, lparam : dword;
    f : real;
begin
f := 2.5;

wparam := dword(( pointer(@f) )^);
lparam := dword(( pointer(dword(@f)+4) )^);

f := 0;

dword((@f)^) := wparam;
dword(pointer(dword(@f)+4)^) := lparam;

caption := floattostr(f);
end;