smolnes

A NES emulator in ~5000 significant bytes of c.

Features

Plays some mapper 0/1/2/3/4/7 games.

Screenshots

Building

Probably only builds on Linux and macOS. Try gcc or clang.

$ make

Running

$ ./smolnes <rom.nes>

Keys:

Action	Key
DPAD-UP	↑
DPAD-DOWN	↓
DPAD-LEFT	←
DPAD-RIGHT	→
B	Z
A	X
START	Enter
SELECT	Tab

Updating keys

Look for line 20 in the source code. The following table shows which numbers map to which keyboard keys:

character	number	default key	NES button
\33	27	X	A Button
\35	29	Z	B Button
+	43	Tab	Select Button
(	40	Return	Start Button
R	82	Arrow Up	DPAD Up
Q	81	Arrow Down	DPAD Down
P	80	Arrow Left	DPAD Left
O	79	Arrow Right	DPAD Right

1. Look up the keys you want to replace from this list SDL scancode list
2. Convert the number to its ascii character, or C character literal.
3. Replace this character in the string.

Projects using smolnes

• p2r3/smolnes-nut The smolnes emulator ported to Squirrel for Portal 2 - https://youtu.be/PUTRvF7slYs
• nevesnunes/ghidra-plays-mario Playing NES ROMs with Ghidra's PCode Emulator
• sysprog21/rv32emu Compact and Efficient RISC-V RV32I[MAFC] emulator (uses smolnes as a demo)
• ma.tthias.xyz/en/blog/smolnes-vuln-research/ Vulnerability Research on SmolNES

Let me know if you've used smolnes and I'll add it to the list.