Release Notes

September 25, 2026

• Added local labels: labels starting with a dot (such as .loop) belong to the previous label without a dot, so the same name can be reused in different subroutines.

September 17, 2026

• The DUP directive has been added to repeat data patterns.

September 15, 2026

• Added the INT 5 system call to generate a random number between 0 and AL (inclusive), stored in AL.

September 24, 2025

• Added support for underscores (_) as digit separators in numbers for improved readability, such as 1111_0010b or 1_000.

August 30, 2025

• Added the ability to share programs via URL links with encoded source code.
• Added font size controls directly in the editor status bar.
• Updated keyboard shortcuts for simulator execution controls (F1 for cycle, F2 for instruction, F3 for continuous run, F4 to stop).

August 25, 2025

• Added Light mode support alongside Dark mode.
• Redesigned simulation controls for stepping through execution.
• Added support for program metadata comments in source code to automatically configure devices and specify program details.
• Added a built-in gallery of example programs.

December 26, 2024

• The timer now begins counting after the first write to the CONT register.
• The printer buffer is automatically flushed when the simulation stops.

September 20, 2024

• The TEST instruction has been added.
• Indirect memory access with offset has been added. For example, mov al, [bx+8].

July 31, 2024

The method for adding devices has been changed. Users no longer choose configurations but can select devices arbitrarily.

September 10, 2023

The interrupt vector addresses used by the system are now protected. If a user attempts to write to these addresses, an error will occur.

August 22, 2023

Launch of the new version of VonSim! Compared to the previous version, this release includes:

• animations for microinstructions;
• support for mobile phones and tablets;
• documentation accessible from within the application;
• offline mode (PWA);
• more advanced text editor, with support for opening and saving files;

Many internal changes were made to VonSim's architecture. The most significant for users are:

• smarter assembler that detects syntax and semantic errors, providing clearer and more specific error messages;
• support for direct memory access, such as mov al, [1234h];
• support for character literals, such as cmp al, '0';

2019

Input/output functionality was added to the simulator.

2017

First version of VonSim. Currently stored in the legacy branch. Compared to MSX88, this version:

• is web-based, requiring no installation and is cross-platform;
• has a more modern graphical interface;
• features an integrated text editor with syntax highlighting.

1988

Rubén de Diego Martínez releases the MSX88 simulator for the Universidad Politécnica de Madrid.