Nemu

Nemu is my NES emulator. It currently runs quite a few games. Thanks to WASM, the emulator runs in the browser over at Quaqqer.com/projects/nemu.

Features

• CPU emulation
• PPU emulation (Picture Processing Unit)
• Audio emulation
• Input
• Debugging
  • CPU info viewer
  • PPU info viewer
  • Pattern table viewer
  • Nametable viewer

Mappers

Different games for the NES use different types of cartridges. These cartridges have different internal wirings which must be emulated as well, hence every single type of cartridge must be implemented correctly to support all NES games. The implementations of these cartridges are referred to as mappers.

• Mapper 0 ~10% of games
• Mapper 1 ~28% of games
• Mapper 2 ~11% of games
• Mapper 3 ~6% of games
• Mapper 4 ~24% of games
• Mapper 7 ~3% of games (BATTLETOADS!?!?!?)
• ...

Acknowledgements

Thanks to

• The NESDev wiki for providing a reference for the NES hardware
• Nestest for providing a great test suite for the CPU
• javid9x for videos explaining how the NES PPU works
• The wonderful people over at r/EmuDev's Discord.