yes, along those lines. I don't know how large a subset NaCL is though. And it's yet another target. It would be cool if you could just target x64, and if the browser is running in a box that is new enough (has such a CPU) your thread literally GETS an x64 core whenever it has focus. All of it - same as if if it were a desktop app. Like a coprocessor. (Exactly what was called a silly idea.)
Native Client is a sandbox for running compiled C and C++ code in the browser efficiently and securely, independent of the user’s operating system.