ZILOG — a 1999 DOS demo, reverse-engineered to JavaScript
Port of ZILOG by Sunflower (mrock, falcon, visualize, voomie) — a 32-bit DOS demo (PMODE/W, Watcom C, x87 software 3D at 320×200 true colour).
Playable in the browser, with an explainer page (retro context, scene-by-scene notes, asm inner loops, 3D engine).
- Live site:
site/ is a static site → GitHub Pages (workflow in .github/workflows/pages.yml; enable Settings → Pages → Source: GitHub Actions).
Locally: python3 -m http.server --directory site and open http://localhost:8000.
- Player: pause, skip scene (← / →), fullscreen (F), scene chips, seek bar. Audio is the ported tracker player running in an AudioWorklet.
Layout
| path | what |
|---|
site/index.html, site/js/main.js, player.js, demo.js | page, canvas player, host that drives scenes from the music position |
site/js/core/ | asset container + LZW, GFX and MOB loaders |
site/js/lib/ | fx2d* (2D/post FX, tables, text, flip), mesh3d* (3D engine + rasterisers) |
site/js/music/ | usm.js (Useless Sound System module player, bit-exact), AudioWorklet |
site/js/scenes/ | the 11 loops of main() (scene0..9.js, credits = _g5final.js) and their helpers |
site/data/data.dat | the demo's own asset container (63 LZW files, tail of ZILOG.EXE) |
re/ | reverse-engineering material: NOTES.md, per-area PORT_*.md/SCENE_g*.md, Ghidra decompilation, Unicorn harness re/harness/orig.py |
tools/ | extract.mjs (container from the EXE), render-scene.mjs, refframe.sh, and tools/test/ differential tests |
Verification
Every ported function is compared with the original machine code executed under Unicorn (re/harness/orig.py):
tools/test/run_fx2d.sh (216 vectors), run_3d.sh (206 checks, pixel-exact), run_usm.sh (all 10 448 music blocks, sample-exact),
run_g1.sh … run_g5.sh (scene-specific functions). Whole frames were compared by eye with a DOSBox capture.
Needs python3 with unicorn + capstone and node ≥ 20. ZILOG.EXE (original) is expected in the repo root for tools/extract.mjs.
Credits and rights
ZILOG is © 1999 Sunflower. Original artwork, models and music are theirs and are shown with credit; contact the maintainers to have anything removed.
Sound system: Useless Sound System v1.04 (FreddyV/Useless). DOS extender: PMODE/W (Daredevil & Tran).
