Unfortunately, a simulator running in javascript—and that's what you're suggesting, one way or the other—would run so amazingly slowly that it would be completely useless. Especially one which is, if I understood the latest talk correctly, sub-cycle accurate.
(To give you an idea, I think I recall Ivan saying that their simulator takes/would take 1 week to boot linux—and that's in c!)
Ah, good call. I was thinking of the sort of low-level simulator you'd want to play around with an unfamiliar architecture; but as the technical notes on that link say, no single-stepping. Once you want to actually be able to slow things down enough to watch a system run, then it's typically harder to speed them up again, unless you truly have two separate emulation modes which can switch off. It's doable.
