- Most (if not the entire) x86 instruction set :)

 - Correct me if I'm wrong about when certain instructions
   (like BOUND) appeared in the 8086 instruction set. Nobody
   seems to have clear-cut documentation on precisely what
   revision added what instructions.

 - Find everything wrong with 8086/8088 emulation NOW
   so that in the future, development of 286/386/486
   emulation goes a lot smoother.