rust chip 8 emulator dependencies fastrand instructions implemented 00E0 1NNN 6XNN 7XNN ANNN DXYN 3XNN 4XNN 5XY0 9XY0 8XY0 8XY1 8XY2 8XY3 8XY4 8XY5 8XY6 8XY7 8XYE FX33 FX55 2NNN 00EE FX65 BNNN CXNN FX15 FX07 FX18 tests IBM logo Lot of Tests