ollie wrote: > Jeremy Jackson wrote: > >> Ok put another way: 0xf000 - 0xffff from who's >> point of view, CPU, PCI bus, or ISA bus? >> >> Ok... I see ipl.S for sis630 does a far call right at the >> reset_vector: so the i386 switches from the dummy >> segment descriptor it gets at reset 0xfffff000 to >> 0xfe00. >> >> Sorry kinda thinking outloud here. I think the PIIX4 makes >> 0xf000-0xffff ram, which the >> std BIOS shadows itsself into before jumping >> there, but I'm just guessing. What does the 630 do? >> > > This depends on your southbridge and superio chipset. For SiS 630 it > does jump > to F segment as its first instruction.The chipset will decode F > segment address > to the Flash socket.
BTW, after everything is done. The nvram_on in southbridge.c make the F segment mapped to RAM (for DoC cases). This is because LinuxKernel look F segment for PIRQ table. Ollie
