Supporting extension ROMs and beyond...

SONE Takeshi ts1 at
Tue Aug 19 03:44:00 CEST 2003

On Sun, Aug 17, 2003 at 12:30:49PM -0600, Eric W. Biederman wrote:
> Looking at the various specifications there is an additional route
> we can take.  We can have the 16bit trampoline detect if it is running
> in v86 mode, and if so use the appropriate DPMI/VCPI/XMS functions to
> switch to protected mode instead of our hand crafted code.
> That should allow us to run under Win9x, freedos, and djgpp.  For
> Freebsd we will probably need a couple of the very most common calls
> implemented in the 16bit trampoline as well.  And of course we can
> still implement the legacy entry points.

Very interesting.

> - It is not clear what an Option ROM will care about so being as
>   backward compatible as possible is a real plus.
> - Going with a solution that can (at least in theory) handle
>   all of the legacy backwards compatibility cases will allow us
>   to concentrate on a single implementation.
> - Going with a solution that is primarily 32bit C code will allow us
>   to reuse the code in appropriate ways.
> - Not using v86 mode by default will allow a high degree of
>   compatibility anyway.
> Does a version of ADLO that runs as 32bit C code sound reasonable?

What do you think about non-x86?


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