For a good diagram which shows how the hardware components interconnect
in a PCI machine, check out the one in Intel's PCI chipset datascheets.
For example, in the i440BX (doc number 290633-001), page 1-2, there
is a diagram. I suggest downloading one of the PCI docs (they are free)
from the intel site.
In this chipset the PCI-to-ISA bridge (South Bridge as people like to
call it) contains some of the common ISA hardware functionality, like
DMA/timers/RTC/PICs/IDE/...
So perhaps code for those hardware items in plex86 will require little
change.
A new interface for supporting real PCI devices would include
support for the configuration space etc. This is where we would
plug in new emulation, like for emulation of a more current
video card.
The host bridge (North Bridge) also manages an AGP bus, which
is optimized for a graphics card. But it implements this as
a virtual PCI bus. So programmatically, a video card on
the AGP is quite similar to the same card on the PCI bus.
I'm now reading through some parts of the book:
PCI System Architecture, Fourth Edition
ISBN 0-201-30974-2
Then will begin work on the interface.
If anybody else has thoughts for PCI, please express them.
-Kevin
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Kevin Lawton [EMAIL PROTECTED]
MandrakeSoft, Inc. Plex86 developer
http://www.linux-mandrake.com/ http://www.plex86.org/
