nana's Introduction

Nana (ナナ)

“The more my dreams are fulfilled, the quicklier they become realities losing their shine.”

Nana (manga), by Ai Yazawa

Nana (ナナ) is a Game Boy emulator written in Go. It's far from feature complete and there are still bugs in what it's implemented but what I got here helped me a lot to understand how computers work at one of their lowest levels, I hope this too helps someone else.

ROM Compatibility list

Tetris
The Legend of Zelda: Link's Awakening

Dependencies

Linux dependencies are listed here.

Installation

$ go get github.com/Ruenzuo/nana

Cross-compiling

See libsdl.org/extras/win32/cross/README.txt for information on how to build SDL for 64 bit mingw cross-compiler

$ make build-windows

Pre-compiled binaries

See Releases

Usage

$ nana path/to/rom.gb

Environment variables

NANA_DEBUG: enables buffered debug output to nana.log
NANA_LCD_STATE_DEBUG: includes the LCD state in debug output
NANA_MEMORY_ACCESS_DEBUG: includes the LCD state in debug output
NANA_ENABLE_TEST_PANICS: panic on undefined behaviour
NANA_ENABLE_REWIND: hold F10 to rewind the emulation
NANA_MAX_CYCLES: enables automatic shut down to specific cycle threshold

Building your own emulator

Start with 8-bit system
Performance matters, profile constantly against other emulators to check how you're doing so far. You can get some inspiration from hachiko
Implement the full instruction set + jump table first. Then try your work against an emulation test collection, these are excelent to catch edge cases and implement the bugs the original systems had
Game Boy CPU Manual
Game Boy Programming Manual

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