73 million seconds — JavaScript port

A study port of "73 million seconds" (pULSe, 1998) — a DOS/4GW demo — re-implemented in plain JavaScript and runnable in the browser and in Node 22.

The original executable (73MS.EXE) and archive (73MIL.SEC) were reverse-engineered instruction by instruction; the port reproduces the behaviour of the original engine (data-driven script, effect pipeline, fixed-point/MMX inner loops) rather than approximating "what the effect usually does". The demo and its assets remain © Pulse 1998 — see Credits.

Live demo: https://kassoulet.github.io/73-Million-Seconds-by-Pulse/

What's here

• Faithful engine port — the original script.unr drives the demo: it creates buffers and events that run every frame in layer order. The JS engine parses the same script and scheduler, with the original expression evaluator (compileExpr).
• Effect modules reproducing the 1998 code, each derived from the disassembly:
  • basic2d — fade, blend, lowpass, matrix transforms, palette conversion, interpolator
  • feedback — echo, echo4/6, radial blur, parasite, Reebok, PlayRGB ani
  • scene3d — the real-time 3-D scenes (rasteriser, formats, animation)
  • volumes — plasma, metaballs, marching cubes, sprites
  • flares — particles/flares
• Original music — tour2.xm played through chiptune3/libopenmpt (bundled in docs/vendor).
• No build step, no dependencies — pure ES modules that run unmodified in a browser and in Node.
• Reverse-engineering tooling — a Unicorn-based harness that boots the original binary, calls any function with custom buffers, and renders reference ("golden") frames for byte-level comparison against the port.

Repository layout

docs/                       GitHub Pages site (player + write-up)
  index.html                the page
  js/core.js                Buf, FX registry, expression compiler
  js/engine.js              script parser + per-frame scheduler
  js/xmtime.js              (order,row) -> seconds for tour2.xm
  js/fx/                    effect modules (basic2d, feedback, scene3d, volumes, flares)
  js/main.js                browser player
  notes/<name>.html         per-effect documentation fragments
  assets/                   converted artwork, scenes, script.unr, tour2.xm
re/                         reverse-engineering notes and tools
  NOTES.md                  everything known about 73MS.EXE / 73MIL.SEC
  rel0.bin / relB.bin       unpacked, relocated original image
  ds.py fx.py xref.py       disassembly / effect lookup / xref helpers
  emucore.py boot.py harness.py   Unicorn environment to call original functions
  golden.py                 headless render of the original engine (reference frames)
tools/                      render.mjs, mkraw.py, ppm2png.py, cmp.py, mkmanifest.mjs, browser-test.mjs
73MS.EXE 73MIL.SEC 73MS.NFO original (unmodified) demo files
ENGINE.md                   the port's engine contract / contributor guide

Running locally

The site is static; serve docs/ and open it:

cd docs && python3 -m http.server
# http://localhost:8000

Render the port headlessly at a given time (needs the raw assets built once):

python3 tools/mkraw.py                       # requires Pillow, builds build/raw
node tools/render.mjs 30 out.ppm --warm=1.5  # render port at t=30s, warm up for feedback
python3 tools/ppm2png.py out.ppm out.png

Compare against the original engine's own output at the same time:

cd re && python3 golden.py 30 31 0.05 golden/
python3 tools/cmp.py out.png golden/...

How the reverse engineering works

re/NOTES.md documents the container format, the engine structures (effect table, event and buffer records, layers, time source) and the loaders. The original is a Watcom C/C++32 binary packed with UPX; rel0.bin is the unpacked image relocated to base 0 so file offsets equal addresses. harness.py restores a booted machine state in ~0.2 s and calls any original function (Watcom register convention) on your own buffers, while golden.py runs the original engine headlessly and saves screen frames used as ground truth for the port. See ENGINE.md for the port's API and the documentation format used in docs/notes/.

Credits

• Original demo 73 million seconds © pULSe 1998 (cookie, Unreal, Camel, Echo, Visualize, Voomie, Keygpls, MySinger and others). Assets are included for non-commercial study of the original code.
• Music: tour2.xm, played with chiptune3 / libopenmpt.
• This JavaScript port and the reverse-engineering notes: non-commercial, for study.