AMD-761 Datasheet, PDF (90/264 Pages) Advanced Micro Devices – AMD-761-TM System Controller Software/BIOS Design Guide

Preliminary Information
AMD-761™ System Controller Software/BIOS Design Guide
24081D—February 2002
Bit Definitions
Bit Name
31–24 PCI_Mem_Top
PCI Top of Memory (Dev0:F0:0x9C)
Function
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
23–0 Reserved
Programming Notes
BIOS should write to this field following completion of the memory sizing algorithm, after
it has determined the total size of the installed memory.
Reserved
78
AMD-761™ System Controller Programmer’s Interface
Chapter 2