[ros-diffs] [ion] 26141: - Don't use the stack in FASTCALL_PROLOG. It messes up NPX checks (this is a bug, it shouldn't happen... related to DPC stack bug.) - Zero out the trap/npx frame for new user-mode threads. - Use KeI386FxsrPresent and not KEI386XMMIPresent when setting up the context for a new thread.