Different people will have differing ideas on how mame should handle them. When I asked about similar things 10 years ago I was told that sometimes some things are not emulated and are handled in a similar direct way. I don't know the specifics but this would just be going one step further. If the smartest brains at intel haven't even theorized a chip technology for their kids to build that will one day run these under "traditional" emulation methods full speed then I'd say it's time to start thinking outside the emubox and let the frigging CPU run the frigging CPU tasks. Or be a deranged masochist. One of the two.