C64 on RETRO.MOE

Announcing Regenerator 2000

Sat, 24 Jan 2026 14:45:00 -0800

I am excited to announce the release of Regenerator 2000, a modern take on the classic Regenerator tool for the Commodore 64 and other 6502-based computers.

Regenerator 2000 is an interactive disassembler for the CPU 6502, focused mostly on Commodore 8-bit computers. It features a modern Terminal User Interface (TUI) with features like x-ref, undo/redo, arrows, keyboard-driven navigation, and more! Better yet, it is multiplatform and runs natively on Windows, macOS, and Linux.

Introducing Unijoysticle 2 C64

Thu, 22 Jun 2023 01:55:46 +0000

Unijoysticle 2 C64 adds Bluetooth gamepad functionality to the Commodore 64/128.

For those familiar with the Unijoysticle 2+, this is the evolution of it.

Features:

One gamepad controls one Joystick
or two gamepads control two Joystick
or one gamepad controls two Joysticks (for Dual Stick games)
or use Wii Steering Wheel
or use Wii Balance Board
Supports gamepad rumble for certain games
Supports C64 GS buttons (2nd and 3rd button) for C64 GS games
Supports additional 4th and 5th buttons (Select + Start) button for certain games

A multi-platform 256-byte intro

Sun, 05 Sep 2021 21:35:04 +0000

https://www.youtube.com/watch?v=nCzAlfXOOXo

“Amor para Dos” is a multi-platform 256-byte intro. The binary, without any kind of modification, can run both on:

a 80386 (or better) + DOS
and on a Commodore 64.

We ( L.I.A) released it at Flashparty 2021. I did the coding.

Commando disassembled - fully commented code

Wed, 02 Oct 2019 15:51:34 +0000

In order to create Commando 2084, I had to disassemble Commando. My original intention was to patch what was only needed and stop there. But I got carried away and I ended up analyzing and commenting the entire Commando code.

The commented code (that can be recompiled to generate the exact original binary) is here:

https://gitlab.com/ricardoquesada/c64-commando-2084/tree/orig

Findings - Level 2

Apparently, the original idea was to ship Commando with 4 levels instead of 3. There is a lot of code/data that indicates that a “level 2” (the levels that are shipped with Commando are level 0, 1 and 3) was in progress, or even finished.

Commando 2084 - a game for the Commodore 64

Sun, 29 Sep 2019 14:45:14 +0000

Commando 2084 is the mix between Commando and Robotron 2084: it is like the original Commando game, but using the Robotron 2084 controls.

Commodore 64 Assembly Tutorial - Part II

Thu, 10 Aug 2017 15:48:10 +0000

A few months ago we ( Pungas de Villa Martelli) released the 4Kindness, a 4K intro for Silesia Party 8. And recently we released its source and a tutorial detailing how we built it.

Without further ado, here it is:

If you have doubts/questions about it, let us know!

The UniJoystiCle v0.4 released

Mon, 28 Nov 2016 14:45:26 +0000

Christmas is coming. Treat yourself with The UniJoystiCle v0.4, and be the cool kid in the block by playing The Uni Games like a pro (that’s it with real unicycles!):

Highlights of v0.4

WiFi Device

Smaller real estate: Fits in all C64/128 models, including the C128D / SX-64 machines
Using Wemos D1 Mini instead of NodeMCU
Blue instead of red

Firmware

New WiFi modes: Station and WPS modes
Auto-reset joystick state after inactivity timeout
Online-firmware update
Stats:
- How many joystick movements
- How many seconds spent in joystick movements

Clients

Android Client: Yay, Android has its own client. Similar to iOS, but without the Gyruss mode.
- Supports any Android game controller like OUYA, Amazon Fire, Moya, etc.
Desktop Client:
- Supports Dpad, Commando and Commodore Home modes
- Windows version: Supports any Xinput game controller(like the Xbox 360 or newer controllers)
- Mac version: Supports any MFi game controller
iOS Client: Added Commodore Home mode
- Supports both MFi and iCade game controllers

Read the complete Changelog here.

UniJoystiCle v0.4.0-RC released!

Tue, 08 Nov 2016 08:52:02 +0000

UniJoystiCle v0.4.0-RC (Release Candidate) released. Mega update!

Download:

iOS client v0.4.6: App Store
Android client v0.4.10: Google Play
macOS client v0.4.0: UniJoystiCle Controller.dmg
win32 client v0.4.0: unijoysticle_controller.win32.zip
Firmware v0.4.5: unijoysticle_firmware.bin
Source code + schematic + layout:https://github.com/ricardoquesada/unijoysticle

Latest versions can be downloaded from here:http://ricardoquesada.github.io/unijoysticle/

Summary:

Use your Xbox game controllers to play C64 games! (from the Win32 client)
Use any iOS or Android game controller to play C64 games! (from the iOS / Android client)
Play games like Commando and Turrican II by only using your game controller. “Space” is mapped to button “B”. There is no need to press the “spacebar”.
Put your device in Station mode (share your local Wifi network).

Full Changelog:

UniJoystiCle update #2

Tue, 27 Sep 2016 18:18:00 +0000

TL;DR

Station Mode (with or without WPS)
Inactivity timeout & Joystick statistics
Auto-firmware upgrade
Better ways to power the WiFi device

Station mode and other features

One thing that bothered me was that I needed to switch WiFi networks every time that I wanted to use the UniJoystiCle. Not a major issue, but not ideal specially if you use your phone both for the UniJoystiCle and for “regular” stuff.

UniJoystiCle Commando Mode, Game Controllers and other news

Tue, 13 Sep 2016 01:17:53 +0000

Since UniJoystiCle v0.3 was released back in July many things were added.

Android client: It has all the iOS features, except Gyruss mode which will be added soon.

iOS client: It is available on the App Store.

Gyruss mode: Allows you to control the direction (up/down/left/right) using gravity.

Linear mode: This was designed to control the header of the MPS-803 printer. More on this on a future blog post.

D-pad mode + Game Controllers: You can use any iOS or Android game controller to play any C64 game. You can even use button “B” to jump, or swap buttons “A” and “B”.

UniJoystiCle news #1

Tue, 13 Sep 2016 01:14:14 +0000

I’ve just released a new firmware version for the UniJoystiCle (v0.4.0). It supports the new Commando Mode.

The new Android client with Commando mode can be downloaded from here:

https://play.google.com/store/apps/details?id=moe.retro.unijoysticle

The iOS client will be available as soon as Apple approves it (usually a few days) and will be available here:

https://itunes.apple.com/us/app/unijoysticle-controller/id1130131741?mt=8

In order to upgrade the firmware, please follow these steps:

DOCUMENTATION.md

The Commando mode allows you to play games that:

¡Arriba las Manos! (Hands up!) music disk for the c64

Mon, 30 May 2016 15:37:07 +0000

A few weeks ago, we, the Pungas de Villa Martelli, released “¡Arriba las Manos!”, a music disk for the Commodore 64.

It includes ten 8-bit songs, an animated hi-res graphic, an easter-egg, and you can control it with a joystick, or a mouse or the keyboard! Not even Apple puts so much love in the UX like us (the future is the c64!)

UniJoystiCle v0.2 coming soon

Sat, 23 Apr 2016 01:37:29 +0000

UniJoystiCle v0.2 coming soon.

Changes in v0.2:

[NEW] - ESP8266 device: supports 2 joysticks (uses three 4066 ICs instead of two
[NEW] - ESP8266 firmware uses AP mode by default. Uses SSID “unijosyticle” + last 2 bytes of mac address
[NEW] - iOS Client: Can be configured to use either joystick port
[NEW] - iOS Client: Auto-discover ESP8266 firmware using mDNS
[NEW] - iOS Client: UniJoystiCle mode also supports up, down and fire (jump)
[FIX] - Name: Renamed project from Uni-Joysti-Cle to UniJoystiCle (easier to search, shorter to type)
[FIX] - ESP8266 device: replaced NodeMCU LoLin with NodeMCU Amica
[FIX] - Sophisticated Glue Material: Uses gaffer tape, instead of duct tape

Announcing the Uni-Joysti-Cle™

Wed, 06 Apr 2016 16:02:10 +0000

The Uni-Joysti-Cle™: The first and only solution to play Commodore 64 video games with your unicycle. Unique immersive experience, much better than VR.

It consists of five beautifully designed parts:

The _Uni Games_video game for the Commodore 64
The Uni-Joysti-Cle™ WiFi receiver, and its firmware
The Uni-Joysti-Cle™ smartphone application
A unicycle
Sophisticated glue material

Find all the information about this revolutionary device here: unijoysticle

The Uni Games - Part II. Reboot

Sun, 27 Mar 2016 15:46:20 +0000

A reboot was needed. I rewrote most of the code. The game is no longer called “The Muni Race”. Instead it is called “The Uni Games” since it will have more than one event (think of “Summer Games” but for unicycles. UNICON basically).

The game will have a more-retro look and feel than before. It will only use PETSCII chars, plus sprites. No redefined characters, no bitmaps. Pure PETSCII. Pure retro effects.

Disassembling 6502 code with Radare - Part II

Thu, 10 Dec 2015 02:54:47 +0000

Let’s crack a simple game. If you are not familiar with Radare, read Part I first.

Creating and opening a VICE Snapshot file

Let’s crack BC’s Quest For Tires since its copy-protection is easy to bypass.

Unzip this file: http://tapes.c64.no/tapes/BCsQuestForTires.zip
Open the tap file with VICE (the most popular Commodore 64 emulator), and..
…the game has some kind of copy-protection. If we enter invalid codes, we won’t be able to play the game.

Since Radare supports VICE Snapshot File format, we can save an snapshot of the game, and analyze it with Radare.

In VICE, go to the menu, Snapshot -> Save Snapshot Image…
- If we select “Save ROMs”, then the BASIC ROM and the KERNAL ROM will be saved inside the Snapshot file, and will be included as Radare sections.

Radare VICE Snapshot File (VSF) support lets us inspect:

The 64k RAM of the computer at the moment the snapshot was saved
The BASIC and KERNAL ROMs in case they were saved.

To open a VSF file, just pass the VSF file as the first argument:

0x00005689 is the PC (program counter) at the moment the snapshot was saved.

Cutting edge coding & debugging techniques during my early days

Sat, 05 Dec 2015 01:55:10 +0000

Cutting edge coding & debugging techniques:

Constelación Commodore

Wed, 25 Nov 2015 19:13:19 +0000

El amigo @SirArthur72 tiene un podcast de Commodore llamado Constelación Commodore. Es un podcast lleno de información de aquella época. En particular la sección “Bunkerpedia” es para escucharla varias veces, con toda la historia de Commodore, desde sus primeros inicios, hasta el final, lleno de detalles.

Una particularidad del podcast, es que cada episodio dura más de 5 horas. En el último episodio (#8), se toca el tema de la C128, y aparezco yo en el podcast contando mis aventuras que tuve con esta linda computadora durante mi juventud. Aparezco alrededor de la hora 4:12 del podcast.

Disassembling 6502 code with Radare - Part I

Thu, 19 Nov 2015 06:52:23 +0000

Radare is an open source portable reversing framework that can do many things, among those things it can disassemble 6502 code.

Download and install radare

First, download radare from github. You need a recent version in order to disassemble 6502 code.
And then install it by running sys/install.sh (or sys/user.sh for local installation):

Loading a c64 .prg

Radare has many command line options. But in order to load 6502 programs we need just two:

-a6502 to specify the 6502 architecture.
-mMemoryAddress to map the file to a certain memory address. Use 2047 for “normal” programs. Usually they start at $0801 (2049), but we have to subtract 2 from the .prg header.

Example:

Disassembling

Radare doesn’t have a GUI, like IDA. Instead is has a powerful command line interface (think of GDB). Example:

And 0x7ff (2047) is the seek address, meaning that all commands will use that address as the base address. Let’s print the first 32 bytes. ( px = print hexa):

The “2061” that we see, is part of the BASIC “SYS 2061” command that usually appears in all C64 programs. So, let’s disassemble the first 12 instructions from 2061. ( pd = print disassemble):

In case we don’t know the meaning of a certain opcode, we can print its description with ?d:

Or if we want to print the description in every disassembled line, we can do:

And then disassemble again:

For more disassembling options just type p?

Coding for the Commodore 64: What changed in the last 25 years

Mon, 02 Feb 2015 06:17:03 +0000

I stopped developing for the Commodore 64 in 1993. Since then a lot has happened:

Back in late 80’s ~beginning of 90’s

I did all my coding using the Commodore 128’sMONITOR command
- That means no text editor, no compiler, no linker. Similar to the debug.com command that used to be in DOS.
Since I didn’t use a text editor, I put all my comments in a notepad (I still have that notepad somewhere)
I used the Commodore 128’s SPRDEF as the Sprite editor.
I used my own character editor called vchar… (later I created a similar one for DOS and Linux)
I did some basic graphics using a graphics editor… but I can’t remember which one.
I didn’t know any other C64 developer, so I did everything kind of isolated
- My sources of information wereCommodore Magazine, Tu Micro Commodore and some books.
- I reversed engineer some games / demos in order to learn tricks.
- I had a 300 bps modem but I didn’t find any good C64 BBS.
- I did some cracks for a local company that was “publishing” (AKA pirating) games. In exchange they were providing me games. To put things into perspective it was impossible (I mean IMPOSSIBLE) to get original games in Argentina back then.
I knew some basic tricks like how to use more than 8 sprites, how to open the top and bottom borders, some raster effects… but nothing very advanced.
I loaded all my programs / games using the disk drive, which was much faster than the datasette, but still very slow
I had a fast-loader cartridge to accelerate the disk drive loading times. It also had a rudimentary MONITOR.
Although Argentina was using the PAL-N standard I had a NTSC Commodore 128. In Argentina we also had the Argentinean Commodore, called Drean Commodore, which was a PAL-N machine assembled in Argentina

And now, in 2015

You have different cross-assemblers like:
- ACME
- KickAssembler
- a more
And native assemblers like (the native assemblers were available back then, I simply didn’t know of their existence):
- Turbo Assembler
Many editors like:
- CharPad (a level editor using characters for Windows. Works with Wine)
- SpritePad (a sprite editor for Windows. Works with Wine)
- HermIRES(a PC/Mac/Linux graphics editor)
- GoatTracker (a music tracker)
You even have complete IDEs like:
Cross-crunchers(compressors) like:
- Exomizer
All the existing C64 tricks are documented here (if it is not there, then it doesn’t exist):
- Codebase64:
  - How to open the side borders
  - Sprite multiplexers
  - 3d effects
  - and much much more
Many tutorials. A good place to start is here:
- Dustlayer
All books and magazines from the old days were scanned and are available here:
- Magazines
- Books
Active community:
- Lemon64 (English)
- Commodore Mania (Spanish)
An active demo scene:
- csdb.dk
New games… yes people are still releasing new games for the C64, and selling them!
- RGCD
- Even recent popular games were ported ( demakes) to the C64:
  - Canabalt( C64nabalt)
  - Super Crate Box(Super Bread Box)
  - Super Hexagon(Micro Hexagon)
Cartridges that support loading games from SD memory cards… no more disk drives or datasettes. These cartridges act as fast loaders among other things:
- Turbo Chamaleon
- Ultimate 1541
Great Emulators (they emulate everything, including VIC bugs, undocumented opcodes, etc.):
- VICE (Win/Mac/Linux)
- CCS64 (Win only)
Multi system TVs… (one TV both for PAL and NTSC machines)
- 220 electronics
And probably many other things that I’m forgetting

As a reminder, the Commodore 64 was released in 1982!. It is impressive all the things that can be done in a 30+ years old computer!