VirtualC64 for macOS

25.10.2025  VirtualC64 6.0 Beta 1 released

Originally, I had planned to release VirtualC64 versions 5.4, 5.5, and so on, gradually migrating the latest code changes from vAmiga step by step. However, I’ve changed plans and recently ported nearly all of vAmiga’s new features at once. Given the scale of these changes, I decided to bump the version number to 6.0, especially because this release introduces workspaces as the new document format for the emulator. Main Changes:

• Workspaces
  A workspace is a bundle containing ROMs, media files, and configuration scripts. When a workspace is loaded, the ROMs are automatically installed, disks and cartridges are mounted, and the configuration script is executed before the emulator reboots. Essentially, it represents a complete working environment that restores itself automatically.
  Since the configuration script syntax is relatively stable, workspaces avoid the compatibility issues of snapshots, whose format often changes between releases, making older snapshots unusable after updates. Snapshots remain available, though, and can still be saved and loaded from the File menu.
• Unified Settings
  Until now, settings were split into Preferences (shared among emulator instances) and Virtual Machine Configurations (unique to each instance). In version 6.0, all settings are unified into a single settings dialog, simplifying configuration management.
• Enhanced RetroShell
  The RetroShell parser has been replaced by vAmiga’s latest version, offering more flexible command parsing and support for more complex syntax variants. Note that some command syntaxes have changed, so older configuration scripts may no longer be fully compatible.
• Adaptive Sample Rate (ASR)
  VirtualC64 6.0 features improved sample rate adjustment, significantly reducing buffer underflows and overflows. This allowed for a smaller audio buffer, which in turn decreases the delay between video and audio output.
• GamePad Database
  Version 6.0 now uses the SDL GamePad database to recognize connected controllers. This feature, borrowed from vAmiga, improves overall gamepad compatibility and support.
• Redesigned Toolbars
  All window toolbars are now created manually to improve compatibility with macOS Tahoe. However, Tahoe is still not officially supported, as I prefer not to invest time fixing issues on what I still consider one of Apple’s biggest missteps.

26.12.2024  VirtualC64 5.1 released

This release features massively improved REU support and fixes several minor bugs.

21.7.2024  VirtualC64 5.0 released

VirtualC64 5.0 has finally been released.

24.6.2024  VirtualC64 5.0 Beta 6 released

Today, the sixth beta of version 5.0 has been released. As expected, the numerous changes in the new core have introduced minor and major bugs, but most of these should have been fixed by now. In the meantime, we have also managed to compile the new core under WebAssembly, allowing the web-port maintainers to update the v5 core shortly.

8.6.2024  VirtualC64 5.0 on the home straight

Today, the second beta of VirtualC64 5.0 has been released. This update was initially planned as version 4.8, with run-ahead support as its most prominent new feature. In run-ahead mode, two emulator instances operate side-by-side: a primary instance emulating the C64 as usual and a run-ahead instance running several frames ahead. The run-ahead instance generates the image texture, requiring both instances to run in sync with a time delay. Whenever the primary instance's execution state changes, such as by a joystick event, the emulator must update the run-ahead instance accordingly. For seamless synchronization, it is crucial to recognize every externally initiated state change in the primary instance.

This necessity prompted a fundamental revision of the emulator's external API. The extensive changes to the emulator's architecture warranted skipping the version 4.8 designation and releasing it as version 5.0 instead. From a developer's perspective, the effort has been worthwhile. The internal code architecture has significantly improved, becoming more streamlined than ever. However, these numerous changes have introduced some bugs, as expected in such a substantial update.

The current version is in the beta phase, and I highly value your participation in testing. Your feedback is crucial for fine-tuning the software. Once the beta version achieves the stability level of the current version 4.7, version 5.0 will be officially released.