tinyred

A tiny Game Boy emulator in C, targeted at Pokemon Red.

Features

• boots and plays Pokemon Red
• SDL windowed output
• readable main source

Build

make run

47-line source:

make run-min

Files

• tinyred.c - readable, commented version
• tinyred_min.c - 47-line code-golf version

How It Works

• starts after the boot ROM with normal DMG register values
• emulates the LR35902 CPU with compact opcode patterns
• maps ROM, VRAM, WRAM, OAM, IO, HRAM, and interrupts through one bus
• implements just enough MBC3 banking for Pokemon Red
• draws the Game Boy background, window, and sprites scanline by scanline
• advances DIV, TIMA, LCD modes, VBlank, STAT, and joypad polling once per frame

Controls

• w/a/s/d or arrows - d-pad
• j / x - A
• k / z - B
• space - Select
• enter - Start
• q / Esc - quit