emulator can run slowly

[city41]

Some people have recorded videos of smaghetti and in those videos the emulator runs very slow, like 10fps or so. I have also found it runs pretty slowly in Firefox and Safari, even on a very high end machine.

Honestly not sure what can really be done about this. I did some quick profiling and it looks to be death by a million paper cuts. Some specific thumb/arm opcode calls dominate the profile (that is, compared to other opcodes, they don't dominate the entire profile), so possibly for those specific instructions, removing the closure and generating a function each time might help.

Barring that, switching to a web assembly based emulator might be needed.

[city41]

actually calls related to updating the canvas, pushPixel, renderScanline and finishScanline make up a large chunk of the profile too, and they might have some optimization opportunities.

[city41]

another possibility, is the emulator spending a lot of time checking for things that sma4 never uses? would it be possible to pair the emulator down to just what is needed for sma4? seems like a long shot and a ton of work, but really learning gba internals and how gba.js works would probably be beneficial in general.