OPL2 FM shim: v86 emulates Sound Blaster 16 PCM but
not the AdLib OPL2 FM chip at port 0x388. We intercept the OS's
writes to 0x388/0x389 and forward them to a small WebAudio-based
2-op FM synth (vendor/opl/opl2-webaudio.js), so Doom's
in-game music, fmtest, opltest, and
musictst are now audible in the browser. It's an
approximation — instruments don't match a real YM3812 — but the
melody is recognisable. For the authentic chip sound, run
os-hdd.img locally in QEMU
(qemu-system-i386 -drive file=os-hdd.img,format=raw -soundhw sb16,adlib)
or 86Box.