wined3d: Make forced reading of a byte in flush_to_framebuffer_drawpixels more reliable.

[Gerald Pfeifer]

Looking at the current code in flush_to_framebuffer_drawpixels it occurs 
to me that we really need to mark the memory we want to _read_ volatile, 
not the local variable that is used to "force" reading said memory.

That is more direct, more logical, and even more efficient.

Looking at the generated code of all of dlls/wined3d/surface.c the
only material difference is

  movb    %al, -25(%ebp)

which is saving the byte we are trying to read onto the stack and into
the local variable.  And that is the part that indeed is not necessary.

Gerald

---
 dlls/wined3d/surface.c |    3 +--
 1 files changed, 1 insertions(+), 2 deletions(-)

diff --git a/dlls/wined3d/surface.c b/dlls/wined3d/surface.c
index bb18b95..199a1bd 100644
--- a/dlls/wined3d/surface.c
+++ b/dlls/wined3d/surface.c
@@ -1839,8 +1839,7 @@ static void flush_to_framebuffer_drawpixels(IWineD3DSurfaceImpl *This, GLenum fm
      * ReleaseDC, and the app won't use the dc any more afterwards.
      */
     if((This->Flags & SFLAG_DIBSECTION) && !(This->Flags & SFLAG_PBO)) {
-        volatile BYTE read;
-        read = This->resource.allocatedMemory[0];
+        *(volatile BYTE*)This->resource.allocatedMemory;
     }
 
     if(This->Flags & SFLAG_PBO) {
-- 
1.6.6.2