[wahern]

> Since it returns the pointer to the next operation and uses longjmp to stop the program, which means I can get away without lookups and without a loop condition.

That threaded approach would be even faster using computed gotos. The loop conditional is a huge performance killer. Removing it claws back cycles from using function pointers, but it would benefit the computed goto approach at least much.

Personally I find using function pointers make for difficult to read code. Dispatching opcodes with a compact switch statement (or equivalent computed goto construction) makes it easier for me to see the meat of the engine and how it works. If the logic for an opcode is complex it can be easily pushed into a static function (which may or not be inlined, but at such a juncture readability is the primary concern). But for simple operations I prefer it inline, textually, so it's easier to see all the moving parts at once.