A new z386 development update says the open-source FPGA project now runs an i386 implementation based on original microcode across boards including Altera Cyclone V and Gowin GW5A.
Original microcode is the project's central design choice, aimed at preserving close hardware compatibility by recreating how the 80386 interacted with its internal control logic rather than chasing maximum speed.
That approach is far more complex than the earlier z8086 effort because the 386 adds memory management, paging, protected-mode extensions and register-debugging state that the core must track.
Performance is roughly equivalent to a 70 MHz i386, though cycle efficiency is slightly worse, possibly because z386 uses a 16 kB cache versus 32+ kB on the fastest original chips.
The result is already fast enough to run software including DOOM, underscoring the project's role as a hardware archaeology exercise rather than a rival to faster FPGA cores such as ao486.
Will this hyper-accurate i386 replica finally allow enthusiasts to perfectly preserve and run vintage software forever?
By perfectly replicating a 40-year-old CPU, what long-forgotten security flaws and design secrets are now being exposed?
Could this 'digital archaeology' legally challenge how companies protect the secret code that runs all modern processors?