Re: [Etherboot-developers] Q: does xstart work?

[Eric W B. <ebi...@ln...>]

Eric W Biederman <ebi...@ln...> writes:

> ke...@us... (Ken Yap) writes:
> 
> > >Staring at the assembly in xstart there is the following code
> > >snippet:
> > >	pushl	%eax
> > >	ADDR32	LJMPI(_execaddr-_start16)
> > >1:
> > >...
> > >_execaddr:
> > >	.long	0
> > >
> > >What I don't get is how this snippet of code successfully jumps
> > >to an application.  ADDR32 should ljmpi should take a m16:32.
> > >Where the offset which comes first is 32 bits, and the segment
> > >that comes after is 16bits.  I just don't see how that works when
> > >we pass it a m16:16 in execaddr.
> > 
> > _execaddr is filled in with a linear address.

My best guess is that the ADDR32 prefix is just ignored somewhere.
As a linear address doesn't make any sense in 16bit real mode.

Eric