Modular cycle-accurate NES emulator implemented from scratch in modern C++ and built with the help of modern CMake, or that's the goal at least. If all goes according to plan, you should be able to rip the 6502 CPU library out of this and make a C64 or Apple ][ or whatever emulator based on it.
Clone!
git clone https://github.com/evilcorpltd/n_e_s.git
Build!
mkdir build_ && cd build_
cmake ..
make
make test