nes86

NES86

NES86 is an IBM PC emulator for the NES.
The goal of this project is to emulate an Intel 8086 processor and supporting PC hardware well enough to run the Embeddable Linux Kernel Subset (ELKS), including a shell and utilities. It should be possible to run other x86 software as long as it doesn’t require more than a simple serial terminal.

Watch the video!

How to run NES86

Download the NES ROM containing NES86 and ELKS from the releases page. See the Binaries section for descriptions of the available binaries. NES86 is not supported on all platforms. The following platforms have been tested and Mesen2 or an Everdrive N8 Pro is recommended.

platform	working?	issues
Mesen2	✅	none
BizHawk	✅	overscan, quickerNES core incompatible, dev build required
FCEUX	✅	overscan, keyboard detection
Rustico	✅	overscan, no keyboard
ksNes (Animal Crossing)	✅	overscan, no keyboard, special ROM required, mapper hack required
Nestopia	❌	not enough cartridge RAM
Mesen	❌	not enough cartridge RAM
Everdrive N8 Pro	✅	none
Everdrive N8	✅	special ROM required, mapper hack required
PowerPak	❌	many

Binaries

file	description
nes86.nes	standard NES86 ROM
nes86.dbg	standard NES86 ROM debug symbols
nes86_ksnes.nes	NES86 ROM built for Animal Crossing
animal_crossing.gci	Animal Crossing save file with an NES item
mmc5_patch.gci	Animal Crossing MMC5 mapper patch
nes86.gci	NES86 ROM injected in a GameCube save file for use with Animal Crossing
nes86_edfc.nes	NES86 ROM built for the original Everdrive N8
005.RBF	Everdrive N8 MMC5 mapper patched to support NES86

Controls

Family BASIC Keyboard

NES86 supports the Family BASIC Keyboard as an input device. If a keyboard is detected at boot then it will be used automatically.

On-screen Keyboard

If no keyboard is detected at boot then an on-screen keyboard will be made available. Pressing SELECT will open/close the on-screen keyboard. With the keyboard open, pressing B will type the selected key and A serves as a dedicated Enter key.

Joypad Mapping

Joypad buttons are mapped directly to the following keys when the on-screen keyboard is closed. This is done to make it easier to play ttytetris without a keyboard.

joypad button	keyboard key	purpose
A	k	rotate clockwise
B	j	rotate counterclockwise
START	p	pause
SELECT		open keyboard
UP	Space	hard drop
DOWN	s	soft drop
LEFT	h	move left
RIGHT	l	move right

How to build NES86

1. Clone the project and its submodules.
   git clone --recurse-submodules https://github.com/decrazyo/nes86.git
2. Install dependencies.
   apt install make cc65 gcc-ia16-elf

Build ELKS

The following steps will build an ELKS image that is compatible with NES86.

1. Enter the elks directory.
   cd nes86/data/elks/elks/
2. Create a cross directory.
   mkdir cross
3. Setup your environment.
   . ./env.sh
4. Build the cross tool chain. This will take a while.
   tools/build.sh
5. Copy or rename the provided configuration file.
   cp nes86.config .config
6. Build ELKS.
   make all

Build NES86

By default, the NES86 build process will use the ELKS image that was built in the previous step. If you would like to run some other x86 software then you’ll probably need to modify data/Makefile, src/x86/rom.s, and conf/ld.cfg

1. Return to the top level NES86 directory.
   cd ../../../
2. Build NES86.
   make all

The resulting NES ROM can be found at nes86/bin/nes86.nes.

Contributing to NES86

Contributions and ports are welcome. See STYLE.md for the project’s coding style guidelines.