Watch it run
The machines, running in the page. Nothing here is a recording: every frame, every trace and every byte is computed while you look at it, on models built from the chips' own transistors.
A chip you can
see inside
There is no instruction decoder here, no addressing-mode table and no cycle-count lookup. There are 1725 wires and 3510 switches on a die photographed out of a physical chip, and the behaviour falls out of simulating them. A register value is read back off its own storage nodes; a cycle count is something that emerged rather than something that was written down.
Three ways in
Read how it was done
The story and the record: the arc of the work told once from the start, the long reads, the notebook of plans and reports, and where each project introduces itself.
Build on it
The parts you can use: a chip that answers over HTTP, a cartridge format, a registry that re-runs what it publishes, and the bytes from a real Geiger tube.
The projects
4 projects live under this roof, with 27 working parts between them.
6502
A transistor-level MOS 6502 traced from die photographs, and everything built on it: the explorer, the API over the real chip, the warm engine process and the console.
OverviewExplorerThe long reads6502 APIDie RunnerEditorRegistryHalfwave Labvisual6502 Archive
hotbits
True random bytes from the decay of a radioactive source: a Geiger counter on a Pi, with bits taken from the timing between decay events.
The NES console
A working NES built from our own parts: both chips simulated switch by switch, every connection between them checked against recorded reference runs, and a picture path already tested on a real console.
OverviewPlayCreateThe NES at human speedThe chipsThe consoleThe signalThe signal benchComposite, terminatedThe benchThe calibration cartThe console arc's notebookThe console arc, in retrospect
The autopsy
Games taken apart by running them: every routine a game entered, the patterns in its code, its tables and its memory, written down as a listing that assembles back to the cartridge.
Start here if you build things
halfphi
The switch-level engine: die-data parser, netlist, solver. It names no chip and embeds no die data, which is the whole reason it can be depended on freely. Loads the 6502, the 6800 and the Z80 through identical calls.
github.com/tinymachines/halfphiMITa Rust crate
the served release (v0.351) carries halfphi 0.1.6; its six shared files hash to 6102efce4863, identical in both repositories
The 6502 work, piece by piece
Each one exists and runs. 4 of the 6 answer on a public address; the other 2 say why they have none.
halfphi
The switch-level engine: die-data parser, netlist, solver. It names no chip and embeds no die data, which is the whole reason it can be depended on freely. Loads the 6502, the 6800 and the Z80 through identical calls.
- Ships as
- a Rust crate
- Code
- MIT
- Die data
- none: embeds no die data
A crate is a dependency, not a running service. There is nothing to answer an HTTP request, so this piece has no reachability to report.
the 6502 info site
The info site: a WebGL2 die renderer, around 25 derived container kinds, the chip map, the primer, the labs and the measured tables.
- Ships as
- built into a content-hashed dist/, served from a release symlink
- Code
- MIT
- Die data
- CC BY-NC-SA 3.0, derived from visual6502 die data
the 6502 API
Stateless HTTP over the real chip: the whole machine travels in every request and the server keeps no sessions. FastAPI and Pydantic, plus the chip atlas, the cartridge mint and an MCP endpoint.
- Ships as
- uvicorn, with --root-path /api behind nginx
- Code
- MIT
- Die data
- CC BY-NC-SA 3.0, derived from visual6502 die data
halfwave
The warm engine process the API talks to: a line protocol, one parsed netlist, one machine, zero dependencies. Plus a reviewer-built lab on a property of its own.
- Ships as
- a release binary, plus a static lab
- Code
- MIT
- Die data
- CC BY-NC-SA 3.0, derived from visual6502 die data
Die Runner
The console: a 6502 ROM, a page of its memory as the screen, and the browser drawing it. Cartridges, builder pages and the editor.
- Ships as
- static ES modules
- Code
- MIT
- Die data
- CC BY-NC-SA 3.0, derived from visual6502 die data
Die Runner API
The cartridge mint, the console spec and the registry. Publishing re-runs every cartridge on the chip rather than believing the verify block the file arrived with, because a file is something its author can edit.
- Ships as
- routes on the same FastAPI app as the 6502 API, not a service of its own
- Code
- MIT
- Die data
- CC BY-NC-SA 3.0, derived from visual6502 die data
Not a separate service. It is routes on the 6502 API, so probing it would report that service's health a second time under a different name. See the chip-api piece.