sl0pboy - a Game Boy Color emulator (companion to the gbos OS) https://git.sl0p.foo/sl0pboy.git/atom/web/gbcore.js?h=master 2026-09-22T18:48:09Z 2026-09-22T18:48:09Z gbc dev gbc@localhost 2026-09-22T18:48:09Z urn:sha1:a2aa8fbb20cab296d44bcdd23c63c0f76ec52869 zig defaults the wasm stack to 16MB, and that lands in the module's *initial* memory, so every instance allocated 16.25MB before executing an instruction. With several Game Boys on one page that was the dominant cost: 123MB for six. The machine is a static and nothing here recurses deeply, so 256KB is plenty. Per instance: 20.5MB -> 4.8MB of linear memory (six: 123MB -> 29MB). Note the spelling - zig cc rejects -Wl,--stack-size and -zstack-size, and wants -Wl,-z,stack-size=N. With memory no longer the constraint, the page cap goes 6 -> 8 on measurement rather than guesswork. Emulation-only, one thread: 12.5x realtime at 1, 3.1x at 4, 1.5x at 8, and exactly 1.0x at 12 - i.e. ~12 is where a thread runs out of road with nothing left for rendering. 8 holds a verified 60fps each in a real browser with all eight leased. Golden frames are still pixel-exact on cgb-acid2, dmg-acid2, cpu_instrs@600 and pky@400 with its .sav, and two Game Boys still lease and ping 4/4. 2026-09-22T17:50:10Z gbc dev gbc@localhost 2026-09-22T17:50:10Z urn:sha1:c1ce018c20c8b9f10b849c1b10c6862b666ea2f6 /net.html plugs Game Boys into a switch that leases them addresses and routes between them: add one, add another, and they ping each other. Unplug either and its address goes back to the pool for the next one. web/gbhub.js is tools/gbhub (gbos) ported to the browser - SLIP framing, DHCP OFFER/ACK, unicast routing, broadcast flooding and ICMP echo for the gateway. It deliberately has no uplink: NAT needs a TUN device and a tab has no raw sockets, so packets addressed off-net are dropped and logged as "no route" rather than pretending. web/gbcore.js wraps one wasm instantiation as a GameBoy object. Several Game Boys are several instantiations of the same compiled Module - the core keeps its machine in a static, so each gets its own linear memory and is isolated for free. Measured 12.3x realtime per instance, so the page caps at 6. Each card gets a text input, because unframed link bytes are console I/O: it lands on the shell's stdin like tools/gbtype, so you can run `ping 10.0.0.3` without the on-screen keyboard. Verified headless (node, two Game Boys through the hub: 2/2 leases, ping 4/4 received) and in headless Chrome against the live site: 4 Game Boys at 60fps each, leases .2-.5, typing into a card's console pings another, unplug frees the address and a replug reclaims it, no exceptions.