> TCG internal helpers only access to the values passed in arguments, and > do not modify the CPU internal state. Thus they can be declared as > const and pure.
I think this needs an explanatory comment. It's not immediately obvious that tcg_gen_helperN and tcg_gen_helper{32,64} have significantly different semantics. tcg/README also needs updating, specifically: "* Helpers: Using the tcg_gen_helper_x_y it is possible to call any function taking i32, i64 or pointer types. Before calling an helper, all globals are stored at their canonical location and it is assumed that the function can modify them. In the future, function modifiers will be allowed to tell that the helper does not read or write some globals. " Paul