Emulates the GameBoy (monochrome only) pretty decently. All major features are implemented and plenty of games and demoscene releases run.

• GameBoy CPU core (Z80-like)
• LCD controller
  • Tiled primary background & the window (a secondary BG layer)
  • Background scrolling
  • IRQs for VBlank & raster position
  • Sprites & sprite DMA
• Sound
  • 2 square wave channels
  • Wave channel
  • Noise channel
• Joypad (+ IRQ)
• Timer (+ IRQ)
• Dummy serial port (+ IRQ)
  • Some weird games use the transmit IRQ for timing purposes...
• MMC memory mappers + battery-backed save RAM
• VRAM debug viewer
• Save states

• Frequency sweep on the 1st square wave channel
• Real Time Clock in the MMC3
• Non-Nintendo mappers

And of course, plenty of bugs/emulation inaccuracies, see GitHub issues for some details.

You'll need a C++11 compiler, Qt5 headers, and an OpenGL-capable machine. Compile with make. Run with:

./yagb [-t] path/to/rom/file.gb

Use -t to print a trace of all executed instructions and memory accesses made by the CPU or sprite DMA. For example:

[mem rd (CPU)] 0x0100: 00
[insn 00332/153/00000404] 0x0100:       00 => NOP                              A: 0x01 | BC: 0x0013 | DE: 0x00d8 | HL: 0x014d | SP: 0xfffe | Flags: Z-HC. | Cycles: 4
[mem rd (CPU)] 0x0101: c3
[mem rd (CPU)] 0x0102: 50
[mem rd (CPU)] 0x0103: 01
[insn 00332/153/00000408] 0x0101: C3 50 01 => JP 0x0150                        A: 0x01 | BC: 0x0013 | DE: 0x00d8 | HL: 0x014d | SP: 0xfffe | Flags: Z-HC. | Cycles: 16
[mem rd (CPU)] 0x0150: f3
[insn 00332/153/00000424] 0x0150:       F3 => DI                               A: 0x01 | BC: 0x0013 | DE: 0x00d8 | HL: 0x014d | SP: 0xfffe | Flags: Z-HC. | Cycles: 4