> > But I think if you compile code for the x64 processor chip and call it > > from x86 or vice versa then either it doesn't work or you pay a high > > price for thunking from one to the other. I think that's unavoidable > > regardless of OS. > > Right: doesn't work. There's no performance penalty because there's no > 32-64 bit thunking layer. > > https://blogs.msdn.microsoft.com/oldnewthing/20081020-00/?p=20523
An interesting post, but not I think from someone with a deep understanding of the matter. IMHO it would be perfectly possible to chunk either way, within the limitations of a 4GB address space. The WOW64 layer already provides the means for x86 apps to call the x64 Windows API. A thunk can do anything, unless it's physically impossible or blocked by policy. Regards David M Bennett FACS Andl - A New Database Language - andl.org
