Windows (NT) has been cross-platform from day one, so there wasn't any need to emulate anything. The kernel, Win32 and everything that ships by default with it ran on at least x86, x64 (Itanium), x86-64, DEC Alpha, PowerPC and others. So yes, it was likely ported (but I doubt there was significantly more effort than just rebuilding everything, given that the code shouldn't be that unportable to begin with).
