D3D9 Hook bzw. als "proxy.dll"

[Remko]

I think this is a Delphi bug, I remember it because I had a problem with some other winapi call that returned an interface.
I quickly tested this (I used IUnknown because I don't have DirectX):

Delphi-Quellcode:

function Direct3DCreate9(SDKVersion: Cardinal): IUnknown; stdcall; external 'd3d9.dll';

procedure TForm2.Button1Click(Sender: TObject);
var
  Unknown: IUnknown;
begin
  Unknown := Direct3DCreate9(32);
end;

When I look in the CPU window we can see the problem:

Delphi-Quellcode:

Unit2.pas.31: Unknown := Direct3DCreate9(32);
004A3B0F 6A20             push $20
004A3B11 8D45F8           lea eax,[ebp-$08]
004A3B14 50               push eax
004A3B15 E8CEFFFFFF       call Direct3DCreate9

For some reason Delphi put's the result (which is in eax when using stdcall) on stack (push eax).

If I declare like this it looks ok:

Delphi-Quellcode:

function Direct3DCreate9(SDKVersion: Cardinal): Pointer; stdcall; external 'd3d9.dll';

procedure TForm2.Button1Click(Sender: TObject);
var
  Unknown: IUnknown;
begin
  Pointer(Unknown) := Direct3DCreate9(32);
end;

The CPU window shows:

Delphi-Quellcode:

Unit2.pas.31: Pointer(Unknown) := Direct3DCreate9(32);
004A3B0F 6A20             push $20
004A3B11 E8D2FFFFFF       call Direct3DCreate9
004A3B16 8945F8           mov [ebp-$08],eax