Supporting extension ROMs and beyond...

ron minnich rminnich at
Mon Aug 11 19:04:01 CEST 2003

On Mon, 11 Aug 2003, YhLu wrote:

> I try to move the vgabios to freebios2 for 2880. I put the BIOS option rom
> to 0xfff8c000, ( the second 48k).

ah, well, we shouldn't really do that until we resolve the VGA bios 

Looks, however, looke tehre is a bug ... Takeshi can perhaps address it 
better than I. 

I did look at our three options today: emulation, ADLO, and VGABIOS. 

VGABIOS is almost 100% C save for the 32-16 trampoline code. 

ADLO rombios.c is mostly assembly code with C wrappers around it.

Emulation is C. 

Emulation is 256K

ADLO is 64K. 

VGABIOS is much less, something like 16K last time I built it.

The functions that VGABIOS needs to finish up to have as complete support 
as bringing up graphics as ADLO are not that many in number. Which makes 
sense: what a VGA BIOS needs to do is diddle its own registers, so most 
BISO functionality is not that useful for them. 

ADLO will not find the option rom on a card and use it; VGABIOS will. 

The most portable long-term way to go is emulation. I don't have room. 

These are the issues I have seen so far. 


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