Subject: Re: Location for x86emu
To: Joerg Sonnenberger <>
From: Terry Moore <>
List: tech-kern
Date: 12/01/2007 02:16:53
At 05:07 PM 11/30/2007 +0100, Joerg Sonnenberger wrote:
>On Fri, Nov 30, 2007 at 08:54:29AM -0700, Tim Rightnour wrote:
> >
> > On 30-Nov-2007 Joerg Sonnenberger wrote:
> > > src/common could be considered as well, given that it is code that can
> > > be used both in userland and kernel.
> >
> > For me, it would be very useful to have in the prep bootloader.  That being
> > said, I don't know of a particularly good place to put it.
> >
> > How much MD glue code would be required to actually use it?
>On x86 I can get away with mapping the BIOS range, the first page and
>another page for stack and data. The default memory functions just
>expect a 1MB VA mapping and read/write to that. I am just passing IO
>requests through.
>On a different platform, you would have to map the adapter ROM (needs to
>be done on x86 later as well), figure out the VGA port mapping (to be
>done on x86 as well) and provide real functions for the in/out
>callbacks. I do not know yet, if we need to emulate e.g. the i8254, but
>if we want to use vesafb or so, we certainly have to.

I believe that many ROMs call functions in the base BIOS.  In that 
case, wouldn't you also have to provide a BIOS image for them to call 
into?  In the bad old days, certain things were referenced at hard 
addresses, & I imagine that practice is not totally eliminated.