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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
Base Address 1: GART Memory-Mapped Register Base (Dev0:F0:0x14)
Bit
Name
Function
31–12
Base_Addr_High
Base Address High
This bit field forms the upper part of BAR1. This field is loaded by BIOS software.
11–4
Base_Addr_Low
Base Address Low
This bit field is hardwired to return 0s to indicate that 4 Kbytes are allocated to GART
memory-mapped control registers and that the registers always reside in a 4-Kbyte
boundary per
PCI Local Bus Specification
, Revision 2.2.
3
Prefetchable
Prefetchable
This bit is hardwired to 1 to indicate that this range is prefetchable
2–1
Type
Type
This bit field is hardwired to indicate that this base register is 32 bits wide and mapping
can be performed anywhere in the 32-bit address space.
0
Memory
Memory
This bit is hardwired to 0 to indicate that this base address register maps into memory space.