On Sun, Feb 14, 2016 at 05:36:38PM +0000, Michael Brown wrote: > On 14/02/16 15:53, Michael S. Tsirkin wrote: > >>That's for execution of a PXE NBP, rather than a (SAN-booted) disk boot > >>sector. > > > >I actually thought the initial post was about iPXE calling NBP (starting > >at location 07C00h) with a non-zero DS, not about booting from disk. > > The initial post mentioned a "boot sector which works just fine when loaded > directly from BIOS, but doesn't work when loaded by iPXE". That can only be > referring to a disk boot sector, not a PXE NBP. (For a start, the BIOS has > no way to directly load a PXE NBP.) > > >Rephrasing the original question, > > It's not a rephrasing; it's an entirely different question.
True - I was just curious since there are similarities between NBP and boot sector (e.g. both are loaded at 7c00) so sometimes the same code can work as both a boot sector and an NBP. > >do you think %DS should be zeroed when NBP is called then? > > Not according to the PXE spec. > > As far as I can tell, the initial value of %ds is undefined for both a PXE > NBP and a BIOS boot sector. > > Michael Thanks, -- MST _______________________________________________ SeaBIOS mailing list [email protected] http://www.seabios.org/mailman/listinfo/seabios
