> That seems woefully underspecified compared to multithreading in C.
It's not even multithreading yet, it's just a means that support for it might be added.
Also, I don't see why you're complaining about it "compared to multithreading in C". To write for asm.js, you write in C. All this is implementation details for how the C compiler (emscripten, probably) will generate its code.
> Where's my test_and_set? How do I implement locking/mutexes? What's the equivalent of volatile in asmjs? Does it have a memory model like the Java Memory Model/OpenMP Memory Model?
It's not even multithreading yet, it's just a means that support for it might be added.
Also, I don't see why you're complaining about it "compared to multithreading in C". To write for asm.js, you write in C. All this is implementation details for how the C compiler (emscripten, probably) will generate its code.
> Where's my test_and_set? How do I implement locking/mutexes? What's the equivalent of volatile in asmjs? Does it have a memory model like the Java Memory Model/OpenMP Memory Model?
Presumably, locks would be added somehow.