Compile the Dreamcast SDK with GCC 4.x
It didn't take very long to compile my code, but when it came to linking all kinds of trouble awaited me. Whenever I tried to link, most of the C++ symbols (things like string and vector) were missing. After several days trying different linker flags I decided the problem must be with the SDK itself. A quick `nm` of libstdc++.a showed up the problem; only a handful of symbols were in there!I've been using a Docker container to compile my code, which is fortunate because it allowed me to gradually roll back the Fedora version until I hit one that correctly compiled libstdc++. Fedora 21 is where it worked!
The moral of the story is that for some reason, GCC 5.x and above will not correctly compile libstdc++.a from GCC 4.x - so if you're compiling the SDK for C++ code, you're going to need to use an old GCC version.
Don't rely on std::atomic or std::async
The SH4 CPU only has a single limited atomic instruction which rules out support for std::atomic. That by itself wouldn't be so bad, but it turns out that even though the standard defines that std::async can be implemented without atomics, GCC hasn't done that.In most cases it's trivial enough to build what you need using std::mutex and std::thread - but it is a bit of a hassle.
std::chrono::high_resolution_clock ... er... isn't
This had me confused for a while. I had a sample GL application running; a spinning cube, and it would run at a consistent 1FPS. I know the DC is slow compared to modern machines, but, 1FPS for a cube?!Turns out that the "high resolution" timer had an accuracy of 1 second! Using the built-in KallistiOS timer functions fixed it.
