Targets supported by ugBASIC

Commodore VIC-20 (vic20)

The vic20 target has been supported by ugBASIC since version 1.5. The compiler can produce executable files in "prg" format and entire "d64" disks, including files that can be loaded using the language's primitives.

How to start

You can use the SANDBOX to try the ugBASIC compiler, without download anything. This tool has been designed to quickly test whether the code you are writing compiles correctly and determines the desired results.

Since the source is compiled thanks to dedicated servers, separate from the browser you are using, some commands are not available: for example, you cannot load external files or resources by using the LOAD command.

If you need to develop a program with a complete tool, we recommend installing the command line executables (see below) or UGBASIC-IDE.

To write the source code you can use a simply text editor. You can save the program in a text file and then to call the compiler, in order to convert it into an form that your Commodore VIC-20 will be able to execute.

Otherwise you can download and use command line compilers. Here are the direct links to the compilers for the various operating systems. Select the most suitable one for your configuration:

In addition to compiling with the IDE, if you are using Linux or the command line version for Microsoft Windows, you can compile the BASIC source "source.bas" into an executable file using the following command:

ugbc.vic20 -o executable.prg -O prg source.bas
ugbc.vic20 -o disk.d64 -O d64 source.bas

It is therefore possible to run everything with an emulator, such as VICE , or to create a phisical storage, as well.

A good starting point to learn ugBASIC for the vic20 platform is the examples page. The examples provide insight into the syntax and usage of many of the commands and statements available for the language.

Since ugBASIC is an isomorphic language, which does not provide abstractions, it is possible that not all examples work on all targets: those labeled vic20 can be compiled to generate executable files.

If you need help and support, the best place is the official forum, where you can find answers to your questions and receive help.

Games written for Commodore VIC-20 (more...)


This game is a "Connect Four" clone. The objective of the game is to be the first to form a horizontal, vertical, or diagonal line of four of one's own tokens.

Examples for Commodore VIC-20 (more...)

Plotting and graphic modes

Graphical operations are not supported.

Blitting images

At the moment the support for graphics modes is limited to GET and PUT.

Calling and inlining assembly code

With the vic20 target you can include assembly code for the MOS 6502 processor. The code will be placed within the code bank.

Supported video standard

The ugBASIC compiler supports both the Commodore VIC-20 PAL (working frequency: 50 Hz) and NTSC (working frequency: 60 Hz) versions, and automatically detects the working frequency to calibrate the delays. In particular, it defines two constants with the same name, and initializes the constant TICKS PER SECOND.

This is the value of the various constants in the various versions:

VIC-20 PAL0 (FALSE)-1 (TRUE)50

Audio support

The vic20 target supports audio commands, as described on the documentation page.

Joystick and keyboard support

The ugBASIC language supports just one joystick, using the JOY(0) statement, and the keyboard.