[c64] C64Emu 17/07/2026

Bop And Rumble (1986, Beam Software)

C64emu 2026-07-17 17:52 UTC

SIDemu improvements:

• 6581 filter stage biases finally finetuned
• 6581 cutoff curve biases readjusted due to the modified biases
• Filter state changes, OSC3OFF bit and master volume (register $18) now subsampled
• Standard master volume digi and Mahoney digi sounds less noisy

New features:

• Audio output external filter simulation (PREFERENCES > AUDIO SETTINGS > EXTERNAL FILTER)

C64emu 2026-03-06 07:34 UTC

Another 6581 filter algo change:

• More precise 6581 cutoff curve and resonance calculations

Bugfix:

• With some digi players, pending NMI mistakenly called the RUNSTOP/RESTORE handler while the RSID initialization process when changing subtunes with the integrated SID player

C64emu 2026-02-27 17:31 UTC

Another 6581 filter algo change:

• With the latest filter update, some tunes sound better, while others sound worse, but I found the reason why, so now almost everything sounds a little better than with any of the previous versions

Minor changes:

• Console mode was activated in the previous version due to the upcoming integration of the VICE testbench, but since it is not ready yet and the emulator's dual-window mode is annoying, I have temporarily disabled it until I figure out how to implement it

C64emu 2026-02-25 15:02 UTC

Hotfix:

• The new mipmap generation method introduced in the previous version (C64emu 2026-02-16 11:22 UTC) not just faster, but slightly more detailed, and because of this in some cases a stronger moiré effect may visible on the screen. If you prefer the old method, just set CRT_LEGACY_MIPMAP_GENERATION to 1 in the C64emu.cfg file located in the C64emuData folder.

C64emu 2026-02-16 11:22 UTC

Bugfixes:

• Since the last rewrite of the SIDemu subsampler, the pulse output was not pulled up by the TEST bit, so the digi did not work in Chimera and The Last V8 (fixed - Thanks to eLK for pointing out that there is a problem with The Last V8, and to Abynx, for noticing that the same thing happens with Chimera)
• Wine only supports GLSL version 1.2 on macOS, so the renderer did not work properly with it, but the shaders were backported to version 1.2 (the shader version is detected at startup and the corresponding shader is loaded), so from now on C64emu runs properly under Wine as well

Improvements:

• SIDemu in 6581 mode sounds even better due to the completely re-written 6581 filter and the revisited DAC lookup tables

New features:

• Experimental video signal to audio signal leakage simulation (PREFERENCES > AUDIO SETTINGS > VIDEO LEAK)
• SIDemu custom config data is now saved in the config file, so the 3 custom templates in addition to the 5 default templates can now be edited with the SIDemu config program (you may try to recreate the sound of your own beloved SID by changing the cutoff offset)

Minor changes:

• OSD messages can be disabled (PREFERENCES > VIDEO SETTINGS > OSD MESSAGES)
• Tape sounds can be disabled (PREFERENCES > AUDIO SETTINGS > TAPE SOUNDS)

Known bugs/limitations:

• Tape/disk changes and reset are not yet handled by the gameplay recorder
• Disk states currently not being saved to state files so if you save state (or close the emulator) while loading from disk, it will be corrupted (when loading from tape, it is safe to save)
• Not every sprite mode-split situation handled correctly
• Sprite collision flags not half-clock accurate (spritevssprite.prg)
• In 100Hz video mode, forced VSYNC could be 50Hz if a VIC-II frame were displayed only every two frames, but instead, emulation is currently running at double speed
• There is no full 1541 emulation yet

To-do list:

• Complete the implementation of command line options for the VICE testbench
• Finetune 6581 biases to improve the filter distortion accuracy, especially when more than one oscillator routed to the filter
• Joystick customizations
• Add frameskip option to the image sequence recording
• T64 file format support
• Write debugger steps to .csv file optionally
• VIC-II PHI1 description for the debugger
• Corrent handling of 100Hz video modes in forced VSYNC mode
• Save disk/tape changes into gameplay recordings
• SID template customization from the menu
• Rewrite the sprite renderer to correctly handle sprite mode-split situations
• Implement pixel clock-based sprite collision (spritevssprite.prg)
• 1541 full emulation
• Find a better mipmap generation method
• Native linux/macOS versions

C64emu 2025-11-28 15:20 UTC

Bugfixes:

• Krestage 3 now works
• The mounted D64/G64 image now being saved to state files (please read section "Known bugs/limitations")

Improvements:

• Better quality bezel refletion
• Optimized SIDemu handling causing overall speedup
• More advanced synchronization of the emulation and rendering thread
• More precise framerate timing
• Auto frame sync in forced VSYNC mode for high refreshrate monitors (you can use forced VSYNC with 100Hz monitors without speeding up the emulation)

New features:

• TAP file support (press ALT+CTRL+P to play/stop the tape)
• Fast loading (pushing to RAM) PRG files and optionally (not always work properly) files from D64 file selector with CONTROL+ENTER (with BASIC line pointer fixup and device number at address $ab)

Minor changes:

• Display emulation CPU core usage in percent above FPS (press ALT+CTRL+F to always show FPS)
• 6581 filter algo finetuned a little
• New menu item: Acknowledgments

Known bugs/limitations:

• Tape/disk changes and reset are not yet handled by the gameplay recorder
• Disk states currently not being saved to state files so if you save state (or close the emulator) while loading from disk, it will be corrupted (when loading from tape, it is safe to save)

C64emu 2025-09-29 15:10 UTC

Bugfixes:

• Bezel reflection not blurred on some hardware (some GPUs do not support the reuse of render targets or array fetching within a for loop - fixed)
• When saving BMP image files, the red and blue color components were swapped (fixed)
• Reset disables multi-SID (fixed)
• Gameplay replaying does not handle multi-SID settings correctly (fixed)
• SID read-only registers (POTX/POTY/OSC3/ENV3) were not saved in the state files nor in the gameplay recording files (fixed)

Improvements:

• Emulation and rendering are now running in separate threads, which should help eliminate lag on slower PCs
• Rewritten sound synchronization to eliminate pops and clicks, audio latency has also been reduced (can be fine-tuned in the config file)
• More stable scope and spectrum analyzer

New features:

• 64-bit compile in separate executable, which may or may not be faster on your computer
• Experimental NTSC VIC-II model (unfortunately I don't have any NTSC C64, so I could only rely on the VICE test programs, so not everything works properly yet, but in general it's somewhat functional)
• In SID player mode, NTSC tunes will automatically switch to NTSC VIC-II model
• Gameplay recordings can be rendered as image sequences with audio in a separate WAV file, for creating video files with external programs (sound output is muted during rendering)
• SID video rendering function in SID player mode even with visualizers as image sequence + WAV (automatically records the music from the beginning and stops at the end if the HVSC songlength database is available)
• New visualizer mode that shows only the oscillators, without the mixed output.
• Game controller support (beta with very primitive functionality and not yet mappable, I will improve it soon)
• 1351 mouse emulation with mouse, touchpad or analog game controller (mouse grab is only activated in fullscreen mode)

Minor changes:

• If there is no config file, the default SID model for the newly created one will be 8580R5, with surround effect disabled
• The system menu structure has slightly changed due to the new features

C64emu 2025-08-21 16:56 UTC

• The very first public release of the emulator