Supporting extension ROMs and beyond...

Stefan Reinauer stepan at
Tue Aug 12 07:35:01 CEST 2003

* Stefan Reinauer <stepan at> [030812 12:36]:
>  1) x86 realmode code execution.
>  2) legacy api emulation/implementation (pcibios, etc)
> In my opinion writing the legacy emulation code (2) in C certainly makes
> sense, since it will run on all platforms by recompiling and it can be
> driven by either the realmode idt code (like in linuxbios1) or by an
> x86emu, depending on your platform.

I looked at the official x86emu code at

This contains something pretty similar than what we need in the v86bios
directory. It's a bios emulation that either plugs into vm86 or x86emu.

> Looking at the size I got the x86emu emulation including an incomplete
> legacy bios emulation plus userland pci code (testbios) to 
> below 150k with -Os, so it would fit in a 256k rom with linuxbios and
> etherboot pretty easily. On x86 most of the code can be dropped leaving
> probably less than 32k for the legacy emulation.
compiling v86bios.vm86 from above I get everything into 20k.


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