Deecy
senryoku.github.io
What it is
Deecy is an experimental, open-source Dreamcast emulator written in Zig for Windows and Linux. Its command-line interface loads .gdi, .cdi and .chd disc files, but setup requires users to provide BIOS and flash dumps named dc_boot.bin and dc_flash.bin in the data folder, then choose the directory containing disc images. Deecy should detect and map controllers automatically; users can also assign guest ports manually and customize keyboard bindings. Keyboard shortcuts provide four save-state slots and four matching load-state slots. The emulator supports fullscreen toggling and an unlimited emulation-speed mode. On Linux, the --scif option pipes a serial port to /tmp/deecy/scif for dcload-serial prototyping. DreamPicoPort support is available as an optional build dependency and can be disabled at build time. The project maintains a compatibility list and directs bug reports to its GitHub issue tracker, though issue creation is restricted. The project lists unfinished areas including AICA filtering, framebuffer handling, exclusion modifier volumes and renderer features. The main project is MIT licensed, with MAME data under BSD-3-Clause and CHD features based on MAME code. Unstable builds are available for Windows and Linux.
Spec sheet
- Product
- Deecy is an open source Dreamcast emulator for Windows and Linux.Read 1 Oct 2026 · senryoku.github.io
- Support
- The project directs users to the GitHub issue tracker for bug reports.Read 1 Oct 2026 · senryoku.github.io
- Maker
- Sen describes himself as a software developer from France and identifies the project account as Senryoku.Read 1 Oct 2026 · github.com
- BIOS requirement
- Installation requires copying BIOS and flash dumps named dc_boot.bin and dc_flash.bin into the data folder.Read 1 Oct 2026 · senryoku.github.io
- Compatibility
- The project maintains a compatibility list and accepts contributions to its dedicated compatibility repository.Read 1 Oct 2026 · senryoku.github.io
- Controller support
- Deecy should automatically detect, map and use controllers, with manual assignment to guest controller ports available in Settings.Read 1 Oct 2026 · raw.githubusercontent.com
- Disc formats
- The command line interface can load and execute .gdi, .cdi and .chd disc files.Read 1 Oct 2026 · raw.githubusercontent.com
- Disc images
- Users select the folder where their Dreamcast disc images are stored.Read 1 Oct 2026 · senryoku.github.io
- Downloads
- The official site provides unstable builds for Windows and Linux.Read 1 Oct 2026 · senryoku.github.io
- DreamPicoPort
- DreamPicoPort support is available and can be disabled with the -Ddreampicoport=false build option.Read 1 Oct 2026 · raw.githubusercontent.com
- DreamPicoPort integration
- DreamPicoPort support is available as an optional build dependency and can be disabled with -Ddreampicoport=false.Read 30 Sep 2026 · github.com
- fullscreen and speed
- The emulator supports fullscreen toggling and an unlimited emulation-speed mode.Read 30 Sep 2026 · github.com
- funding
- The official site asks supporters to make a one-time donation through GitHub Sponsors.Read 30 Sep 2026 · senryoku.github.io
- installation
- Users download and decompress an archive, place BIOS and flash dumps named dc_boot.bin and dc_flash.bin in the data folder, then choose their disc-image directory.Read 30 Sep 2026 · senryoku.github.io
- Issue intake
- Issue creation is restricted in the Deecy GitHub repository.Read 1 Oct 2026 · github.com
- Keyboard
- Keyboard bindings can be customized in Settings.Read 1 Oct 2026 · raw.githubusercontent.com
- Known limitations
- The README lists exclusion volumes and open translucent modifier volumes as missing renderer features.Read 1 Oct 2026 · raw.githubusercontent.com
- Licensing
- The rest of Deecy is MIT licensed, while included MAME data is BSD-3-Clause licensed.Read 1 Oct 2026 · raw.githubusercontent.com
- Linux serial feature
- The --scif option pipes the serial port to /tmp/deecy/scif on Linux for use with dcload-serial.Read 1 Oct 2026 · raw.githubusercontent.com
- Linux serial integration
- The Linux-only --scif option pipes a serial port to /tmp/deecy/scif for dcload-serial prototyping.Read 30 Sep 2026 · github.com
- operating systems
- The official site describes Deecy as an open-source Dreamcast emulator for Windows and Linux.Read 30 Sep 2026 · senryoku.github.io
- product type
- Deecy is an experimental Dreamcast emulator written in Zig.Read 30 Sep 2026 · github.com
- Save states
- Keyboard shortcuts provide four save-state slots and four load-state slots.Read 1 Oct 2026 · raw.githubusercontent.com
- Technology
- Deecy is an experimental Dreamcast emulator written in Zig.Read 1 Oct 2026 · raw.githubusercontent.com
Strong points and limits
Strong points
- Loads .gdi, .cdi and .chd disc images.
- Includes four save-state and four load-state slots.
- Controller mapping can be automatic or assigned manually.
- Supports fullscreen and unlimited emulation speed.
Limits
- Requires BIOS and flash dumps to run.
- Project lists unfinished emulator areas.
- Available builds are described as unstable.
- Issue creation is restricted in the repository.
Who it suits
Deecy suits Dreamcast enthusiasts and developers on Windows or Linux who can provide the required BIOS files and tolerate an experimental emulator. Its Linux serial option may also suit dcload-serial prototyping.
Verdict
Deecy offers core disc loading, controller and save-state features, with additional options for Linux serial work. Its experimental status, required BIOS files and listed unfinished areas are important considerations.
Where Specifiction places it
- Dreamcast Emulators#6 of 97.8
