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AMD-761™ System Controller Programmer’s Interface
Chapter 2
AMD-761™ System Controller Software/BIOS Design Guide
24081D—February 2002
Preliminary Information
Programming Notes
Bit Definitions
PCI Top of Memory (Dev0:F0:0x9C)
Bit
Name
Function
31–24
PCI_Mem_Top
PCI Memory Top
This 8-bit field is compared to the incoming PCI bus master address to determine if a
memory cycle falls within the AMD-761™ system controller DRAM region, as follows:
31 30 29 28 27 26 25 24 PCIMemTop Field
31 30 29 28 27 26 25 24 PCI Address
BIOS should write to this field following completion of the memory sizing algorithm, after
it has determined the total size of the installed memory.
23–0
Reserved
Reserved