Using an idea from dreNorteR i'm writing a program that will detect if you're running on an emulator with a V20 or actual hardware (at least, any emulator that isn't emulating the V20 microcode).
If I wanted to be evil I could submit it as a bug report
someone should make an interposer board that lets you stick a V20 and an 8088 in your PC and switch between them with a physical switch or something
okay the evil test program lives.
Both the 8088 and V20 leak the value of temporary registers via invalid instruction forms, which is not something you can (easily) emulate in a non-microcode emulator.
If you wanted to be an evil bastard you could use this in a demo.
it doesn't even run in 86box; the CPU hangs.
XTCE-Blue ain't bothered.
The real challenge will be to make this not just crash on other emulators, because I want to print a failure message to really rub it in.
86box seems to fall back to 8088 decoding for V20 illegal operations. That means it executes POP CS.
I can just detect that and print '86box detected' which is appropriately snarky
LOGON SYSTEM, a demogroup for the Amstrad CPC, has this cheeky thing where they greet the name of the emulator the demo is running in.
I've always wanted to do something like that; it would be fairly straightforward to generate some kind of 'fingerprint hash' of edge-case CPU and hardware behavior that uniquely identified a given emulator.
of course the goal would be to make my emulators undetectable by having the same hash as hardware...
Oct 13, 2026, 8:55 PM@gloriouscow Make it a mechanical switch with a shaft extending from the CPU socket to the front panel, and sign me up!