C64 by ChronoCoders

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What C64 by ChronoCoders is

C64 by ChronoCoders is a free emulator for the Commodore 64 and its 1541 disk drive, available for Linux and Windows. Written from scratch in C11, it models the computer and drive as separate machines with independent clock timing and a modelled IEC serial bus. The project says it runs commercial software, including real games verified beyond unit tests.

Its VIC-II implementation covers five graphics modes, sprites, collisions, badlines, raster interrupts, and border effects. The SID 6581 sound model includes oscillators, four waveforms, sync, ring modulation, ADSR, a multimode filter, and 44.1 kHz resampling. Digital components are modelled to the cycle, while the SID filter and mixing use fixed-point approximations.

The 1541 supports LOAD, SAVE, and NEW commands, and writes disk changes back to a D64 image on clean exit. Input options include keyboard mapping modes, joystick port switching, cursor-key joystick controls, and SDL-recognized game controllers. The GUI binary requires a C11 compiler and SDL2; documented verified platforms are Linux x86-64 and Windows x86-64 using MSYS2 MinGW64. The emulator does not include C64 ROM images, which users must supply from legally obtained copies. Repository source code is under the MIT License, which does not cover ROMs or other software used with the emulator.

Who it suits

C64 suits people who want to run Commodore 64 software on Linux or Windows and can provide their own legally obtained ROM images. Its documentation also targets people extending or porting the code, or seeking to understand its behavior.

What it does well

Free to use under the repository's MIT-licensed source code.
Models the computer and 1541 drive on separate clock domains.
Supports VIC-II graphics features and SID 6581 sound.
Can write disk changes back to D64 images on clean exit.
Supports keyboard, joystick, and SDL-recognized game controllers.
Includes a headless mode that can run without an audio device.

What to know first

Users must supply their own legally obtained C64 ROM images.
The GUI binary requires a C11 compiler and SDL2.
Save-state snapshots require matching platform, build, endianness, and compiler ABI.

Limits

The repository provides no bundled ROM images, so running the emulator requires users to provide legally obtained copies. Save-state snapshots are limited to matching platform, build, endianness, and compiler ABI.

Getting started

Open the C64 project on GitHub.
Use a Linux x86-64 or Windows x86-64 environment; Windows builds use MSYS2 MinGW64.
Install a C11 compiler and SDL2 for the GUI binary.
Build the emulator from its C11 source.
Provide legally obtained C64 ROM images to run the emulator.
Load a D64 disk image if you want to use the emulated 1541 drive.

Verdict

Choose C64 by ChronoCoders if you want a free Commodore 64 emulator with a separately modelled 1541 drive and configurable controls. Look elsewhere if you need bundled ROM images or save states that transfer across different builds and platforms.

Questions

Is C64 free?

Yes. The project is free, and its repository source is available under the MIT License.

Which platforms are documented?

The verified platforms are Linux x86-64 and Windows x86-64 using MSYS2 MinGW64.

What does the MIT License cover?

It covers the repository source code. It does not cover ROM images, disk images, cartridges, or other software used with the emulator.

Are ROM images included?

No. Users must provide their own legally obtained C64 ROM images.

What disk image format does the drive support?

The documented disk format is D64. The 1541 supports LOAD, SAVE, and NEW, and writes disk changes to the image on clean exit.

What does the GUI build require?

The GUI binary requires a C11 compiler and SDL2.

Facts from C64 by ChronoCoders's own pages

Accuracy limits: The design notes say digital components are modelled to the cycle while the SID filter and mixing use labelled fixed-point approximations. · github.com, 7 Oct 2026
Audience: The design notes describe the documentation as intended for people extending or porting the code and people seeking to understand or trust its behaviour. · github.com, 7 Oct 2026
Audio and graphics: Its documented features include VIC-II graphics modes and sprites, plus SID 6581 sound resampled to 44.1 kHz. · github.com, 7 Oct 2026
Build requirements: The GUI binary requires a C11 compiler and SDL2; the project documents Linux x86-64 and Windows x86-64 using MSYS2 MinGW64 as verified platforms. · github.com, 7 Oct 2026
Controls: Keyboard, joystick, and SDL-recognized game controllers are supported, with configurable joystick port and keyboard layout. · github.com, 7 Oct 2026
CPU and bus: The C64 and 1541 run in separate clock domains and communicate over a modelled IEC serial bus. · github.com, 7 Oct 2026
Disk drive: The 1541 drive supports LOAD, SAVE, and NEW, with disk changes written back to the .d64 file on clean exit. · github.com, 7 Oct 2026
Disk support: The 1541 model supports LOAD, SAVE, and NEW, and writes disk changes back to the .d64 file on clean exit. · github.com, 7 Oct 2026
Graphics: The VIC-II implementation covers five graphics modes, sprites, collisions, badlines, raster interrupts, and border effects. · github.com, 7 Oct 2026
Hardware emulation: It models the C64 and 1541 as separate machines with independent clock domains and a real IEC serial bus. · github.com, 7 Oct 2026
Headless mode: The emulator supports a --headless mode and can run without an audio device, pacing to realtime from a wall-clock frame timer. · github.com, 7 Oct 2026
Input: Input options include keyboard mapping modes, joystick port switching, cursor-key joystick controls, and SDL-recognized game controllers. · github.com, 7 Oct 2026
License: The repository source code is available under the MIT License, which grants use without charge and disclaims warranties. · github.com, 7 Oct 2026
License limits: The MIT license covers repository source only; it does not cover ROM images, disk images, cartridges, or other software used with the emulator. · github.com, 7 Oct 2026
Maker: The maker profile identifies Altug Tatlisu and lists New York, US as the location. · github.com, 7 Oct 2026
Purpose: C64 is a cycle-accurate Commodore 64 and 1541 disk-drive emulator written from scratch in C11. · github.com, 7 Oct 2026
Requirements: Building requires a C11 compiler and SDL2 for the GUI binary; the project documents Linux x86-64 and Windows x86-64 using MSYS2 MinGW64 as verified platforms. · github.com, 7 Oct 2026
ROM requirement: Copyrighted C64 ROM images are not included, so users must provide their own legally obtained copies to run the emulator. · github.com, 7 Oct 2026
Save states: Snapshots are limited to the same platform, build, endianness, and compiler ABI. · github.com, 7 Oct 2026
Snapshots: Save-state snapshots are limited to the same platform, build, compiler layout, and byte order. · github.com, 7 Oct 2026
Software compatibility: The project says it runs commercial software, including real games verified beyond unit tests. · github.com, 7 Oct 2026
Sound: The SID 6581 model includes oscillators, four waveforms, sync, ring modulation, ADSR, a multimode filter, and 44.1 kHz resampling. · github.com, 7 Oct 2026

Where C64 by ChronoCoders stands on Freedom251

Commodore 64 Emulators#10 of 31