smsPlus64

A Sega Master System, Game Gear and SG-1000 Emulator running on the Nintendo 64. Use it on real hardware with a flashcart. See Compatibility for the hardware it has been tested on.

Built with Libdragon

✅ works    ⚠️ works, with a catch    ❌ does not work    ❔ untested

Reports for anything untested here are welcome.

The emulator code is a port of smsPlus.

Download smsPlus64.z64 from the releases page and copy it to your flashcart.

You can launch ROMs directly from the Everdrive menu. Download sms.v64, gg.v64 and sg.v64 from the releases page and copy them to the ED64/emu folder on your SD card. No renaming needed: all three are the emulator itself, just under the names the Everdrive menu looks for.

Selecting a .sms, .gg or .sg rom in the Everdrive menu then starts it in the emulator. See SG-1000 games for what to expect from .sg roms started this way.

Copy smsPlus64.z64 to the SD card and start it from the Everdrive menu. The built-in game browser reads the card directly, so roms in a smsPlus64 folder at the root of the card are found straight away. If there is no such folder, the browser starts at the root of the card instead.

You can also launch roms directly from the Everdrive menu. Copy smsPlus64.z64 into each of these folders on the SD card:

/ED64/edapp/sms/
/ED64/edapp/gg/
/ED64/edapp/sg/

Selecting a .sms, .gg or .sg rom in the Everdrive menu then starts it in the emulator. The file name does not matter, unlike on the X-series.

The cp64pro.sh script in this repository copies the emulator to the root of the card and to all three folders over USB.

How the PRO is driven, and why it does not go through libcart like the other flashcarts, is described in ED64PRO.md.

Games can be started directly from the N64FlashCartMenu when using a SummerCart64.

To set this up:

1. Copy smsPlus64.z64 to the menu/emulators folder on your SD card.
2. Launch the menu; the emulator will appear automatically.

More details can be found in the N64FlashcartMenu Getting Started Guide and its Emulators page.

To run the emulator as a standalone ROM:

1. On the root of your SD card, create a folder named smsPlus64.
2. Place your .sms, .gg and .sg ROMs in this folder.
   Subfolders are supported; the menu will scan them automatically.
3. Download smsPlus64.z64 from the releases page.
4. Copy it to your flashcart.
5. Launch smsPlus64.z64 from the Everdrive or SummerCart menu.
   The emulator will display its built-in game browser.

Sega SG-1000 cartridge images with the .sg file extension can be played alongside Master System and Game Gear roms.

• SG-1000 games can be started from the built-in game browser, the EverDrive-64 X7 and PRO menus and N64FlashcartMenu.
• The EverDrive-64 X7 menu and N64FlashcartMenu pass a game on without its size or file name, and SG-1000 images have no header to recognise them by. The emulator therefore identifies such a rom from a list of known roms, which also covers Master System and Game Gear games whose rom header is missing or names the wrong console, Master System and Game Gear games of 48 KB or less, which need their real size, and SG-1000 games larger than 48 KB. Any other rom without a header is taken to be an SG-1000 game of 48 KB, which suits nearly all of them. A game that is not recognised this way can always be started from the game browser.
• The RAM expansion used by several Taiwanese releases (for example Knightmare and TwinBee) and the extra cartridge RAM of titles such as The Castle are detected automatically.
• SG-1000 cartridges have no battery-backed saves.
• SC-3000 (.sc) and SF-7000 (.sf) software is not supported.

• D-pad Up / Down: previous or next game
• D-pad Left / Right: previous or next page
• A: open a folder, or start the selected game
• B: go back to the previous folder
• Start: open the settings

• D-Pad: movement
• Z: Pause (Master System and SG-1000)
• Start: Start (Game Gear)
• B: Button 1
• A: Button 2
• Z + Start: return to the game browser. Does nothing for a game started straight from the Everdrive or N64FlashcartMenu; reset the console to get back to that menu.
• Z + C-Right: open the settings

The settings can also be changed with these shortcuts while playing:

• Z + A: show or hide the frame rate
• Z + B: turn sound on or off
• Z + C-Left: change frameskip
• Z + C-Up: show or hide the performance breakdown

Press Start in the game browser, or Z + C-Right while playing. Use Up and Down to pick a setting, Left and Right to change it, and B to go back.

Your settings are saved as settings.cfg in the same folder as your games on the SD card, and are restored the next time you start the emulator. Without an SD card the settings still work, they just cannot be saved.

The frame rate display reads something like SS 060/30 A1:

• first character: S for Master System, G for Game Gear, 1 for SG-1000
• second letter: S when sound is on, M when muted
• 060: how fast the game is running, out of 60
• 30: how many frames per second are actually drawn
• A1: the frameskip setting. A means Auto, followed by the level it settled on; a plain digit is a level you set yourself

The performance breakdown reads something like Z731 R678 B147 A218 I000 S060. Each letter is one part of the work of running a game:

• Z: emulating the game's own processor
• R: drawing the picture
• B: handing the finished picture to the Nintendo 64's graphics chip
• A: sound
• I: spare time, spent waiting so the game runs at the right speed and no faster
• S: waiting for the Nintendo 64's graphics chip to catch up

Each number is how long that part took on one frame, in milliseconds with the dot left out: R678 means 6.78 milliseconds spent drawing. A frame lasts 16.67 milliseconds, so when a game is keeping up the numbers add up to roughly 1667.

I is the one to look at first, because it is the time left over. While there is spare time the game runs at full speed. When I reads 000 there is none left and the game is running slow — and then the biggest of the other numbers is what is costing you. I and S stop counting at 999.

With frameskip on, R and B are averages over all frames, drawn and skipped, so they read lower than the drawing of a single frame actually costs. To see the real cost of drawing a frame, set frameskip to Off.

With Upscale on both displays are drawn over the picture, hiding the first few rows.

• Settings are only saved when a smsPlus64 folder exists on the SD card. The settings screen says so if it cannot save them.

Some games show a black screen, for one of the reasons below. This is the same however the game is started: from the game browser, from an Everdrive menu or from N64FlashcartMenu.

• Korean unlicensed cartridges that use bank switching of their own, such as Jang Pung 3 and Samgukji 3.
• BIOS images, which are not games.

Reports of other games that do not run are welcome.

1. Install the Libdragon SDK. For more info and instructions, see https://github.com/DragonMinded/libdragon
2. Make sure the environment var N64_INST points to the installed SDK
3. Get the sources and build

git clone https://github.com/fhoedemakers/smsplus64.git
cd smsplus64
chmod +x build*.sh
./build.sh

Then copy smsPlus64.z64 to your flash drive.

build.sh leaves the filesystem folder out of the rom, so smsPlus64.z64 lists only what is on the SD card. Use ./build_dfs.sh instead to bake that folder into the rom, so the games in it can be played without a card. No roms come with this repository: put your own .sms, .gg or .sg files in filesystem first, or you will just get a bigger rom with nothing in it.

The list of known roms used for games started from the EverDrive-64 X7 menu or N64FlashcartMenu is injectedroms_table.h. It is generated from a rom collection with tools/injectedroms/gen_injectedroms.py; run it with -h for its usage.

You can also use an Emulator. Libdragon suggests Ares. This however requires building from source. Since an Everdrive is not used, copy your .gg, .sms or .sg files to the filesystem folder of this repository, then run build_dfs.sh. The roms will be baked into smsPlus64.z64

The files run64.sh, cp64.sh are used to run or copy smsPlus64.z64 to the Everdrive, using an USB cable. (using usb64.exe). Since usb64.exe runs on Windows, you need to build the project using WSL (Windows Subsystem for Linux) in order to use these scripts. If you are using Linux, you have to copy the file manually to the Everdrive.

For the EverDrive-64 PRO the equivalents are run64pro.sh and cp64pro.sh, which use edlink.exe instead. cp64pro.sh copies the emulator to the root of the card and to all three edapp folders in one go.

This emulator is other people's work brought together on a Nintendo 64.

Emulation

• SMS Plus by Charles MacDonald — the Sega Master System and Game Gear emulator core in smsplus/ that this project is built on.
• The Z80 CPU core is Juergen Buchmueller's portable Z80 emulator.
• The SG-1000 (TMS9918A) video modes are ported from SMS Plus GX by Charles MacDonald and Eke-Eke, as included in retro-go.
• Detection of the Taiwanese SG-1000 RAM expansion is based on PicoDrive.
• The core reached this project by way of pico-smsplus, the Raspberry Pi Pico version of the same emulator.

Nintendo 64 side

• Libdragon by DragonMinded and its contributors — the open source SDK everything here is built with: display and RDP, audio, controllers, and the filesystem code. The dragon in the game browser is its logo.

• libcart by devwizard (@devwizard64), as bundled with Libdragon — flashcart detection and SD card access on the EverDrive-64 and the SummerCart64.

• ed64-pro-pub by krikzz — the EverDrive-64 PRO developer sources, MIT licensed. ed64pro_drv.c is a trimmed port of the cartridge command protocol from those sources.

• FatFs by ChaN, also by way of Libdragon — reading the SD card.

• SummerCart64 and N64FlashcartMenu by Mateusz Faderewski (@Polprzewodnikowy) — the flashcart and menu that games can be started from directly.

• Thanks to Wayne Reilly and Dan Moore for testing releases on hardware this project does not have and reporting back.

This project

• smsPlus64 — the port to the Nintendo 64, the game browser, the settings screen and the renderer — is by Frank Hoedemakers (@fhoedemakers).
• The game browser and the Frens:: helpers are the same ideas as in pico-infonesPlus and the other emulators in that family, rewritten here for Libdragon.

Part of the code and the documentation was written with the assistance of Anthropic Claude Opus, through Claude Code. It helped with:

• the speed work in v0.8: the per-scanline renderer, frameskip and its automatic cadence, building the sprite list once per frame, and choosing the Z80 optimization level by measurement
• the sound work: generating the PSG per scanline, so digitized speech no longer crackles
• keeping sprite collision correct on skipped frames, and the Blink fix setting
• the settings screen and saving settings to the SD card
• filling the screen with the picture (Upscale), taking the console type from the ROM instead of the file name, and loading the whole ROM whatever its header claims
• the frame rate and profiler overlay, and the tools/collisioncheck host harness
• SG-1000 support: porting the TMS9918A renderer, memory map and interrupt fix from pico-smsplus, sprite status on skipped frames, starting SG-1000 games from the flashcart menus, and the SG-1000 checks in tools/collisioncheck
• this readme and the changelog