Very interesting write-up, thanks! Makes me want to get back into C programming :) How did you manage to learn all of this stuff, for a new, closed-source and relatively undocumented (e.g. @asmname) language?
About the @asmname thing: you can easily dump every default Swift module using a REPL command:
repl> :print_module Swift
There you can find a lot of interesting language lexems and more, so all you have to do is to try using them in your code until you don't figure it out ;)