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Re: PCIRf: How to access PCI Exp. cards in DOS
Keith Jasinski <firstname.lastname@example.org> asks...
> I am looking for any information (either direct information or good book
> recommendations) on how to access PCI cards in DOS (command prompt only,
> not a console window with a Windows driver). I am looking to learn how
> to find the cards on the bus (I believe the BIOS enumerates the bus on
> power up, so that info is somewhere), perform configuration cycles, and
> memory accesses.
the PCI 2.1 BIOS specification has what you need to do the configuration
In DOS, you find devices by using the BIOS calls to scan all possible
BUS/DEV/FUNC combinations, looking for your devices ID. Once you have a
device's BUS/DEV/FUNC 'key' you can then read the rest of its configuration
space, including base registers.
Many PCI devices use memory apertures that are not normally assigned to the
DOS-addressable lower 1MB. You'll need some sort of 'DOS extender' to let you
get into 32bit protected mode in order to address these high locations.