[OpenBIOS] more question on flash on 440gx

Ronald G. Minnich rminnich at lanl.gov
Fri Jan 21 17:06:05 CET 2000

well, curiouser and curioser. 

There's a flash with a 20-bit address space. There's an 8086 addressing
mode with 20 bits. There's lots of ISA and VGA and other junk populating
that 20 bit space, leaving either 64k, 128k, or at most 256k of address
space for the flash (see the 440gx bridge manual: you can go with standard
64k bios, extended bios, or some other mode which lets you get a 256k

OK, so how the heck do you read/write flash? The utility runs in DOS mode.
What's it doing? Is 75% of that flash memory wasted? (hard to believe ...)
Is there a bank register somewhere? Also, how do you get to address 0 on
flash if the only addresses you can use are f0000, e0000, and c0000? does
intel remap address lines? Anybody found a reference schematic for this
motherboard? developer.intel.com is short on specifics ...

This is all very odd. DEC sure got it right on their motherboards, at
least according to the devbios driver.

Anybody know of a cheap nvram for the PCI bus so we can continue testing
while we figure this out?


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