Supporting extension ROMs and beyond...

ron minnich rminnich at
Tue Aug 12 09:16:01 CEST 2003

On Tue, 12 Aug 2003, Stefan Reinauer wrote:

> Emulation and ADLO go hand in hand I think. There are 2 different
> problems to be addressed:

I'm not so sure. The emulation code supports the INT functions needed for 
vga setup. I would actually be inclined to dump ADLO rombios.c completely 
and replace it with real C code. 

ADLO is a great proof-of-concept but after walking the code I find too 
much assembly in there, most of it not needed.

It's the bochs heritage. 

If you look at the x86 emulator in the freebios tree, you can see it 
supports emulation and in addition provides (in normal C, not bcc) 32-bit 
functions for vga calls to the bios.

>  1) x86 realmode code execution.
>  2) legacy api emulation/implementation (pcibios, etc)
> * LinuxBIOS1 on x86 supports 1) directly and does 2 with an emulation
>   (pcibios.c)

I'm not sure I agree with your definitions. 

Emulation means (to me) emulating an x86 via software instruction decoding 
and execution. 

the pcibios code is not doing emulation --  it is supporting pcibios 
functions, albeit in 32-bit mode. 

While the x86emu will fit in with etherboot, it won't fit in with a linux 


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