Chapter 2
AMD-761™ System Controller Programmer’s Interface
131
24081D—February 2002
AMD-761™ System Controller Software/BIOS Design Guide
Preliminary Information
Programming Notes
Bit Definitions
AGP/PCI Memory Limit and Base (Dev1:0x20)
Bit
Name
Function
31–20
MLim[31:20]
Memory Limit Address
Memory limit address defines the top address of the non-prefetchable address range used
by the AGP target (graphics controller) where control registers and FIFO-like
communication interfaces are mapped. The lower 20 bits of address are assumed to be
0xFFFFF. The memory address range adheres to 1-Mbyte alignment and granularity.
19–16
Reserved
Reserved
15–4
MBase[31:20]
Memory Base Address
Memory Base Address defines the base address of the non-prefetchable address range
used by the AGP target (graphics controller) where control registers and FIFO-like
communication interfaces are mapped. Bits [15:4] correspond to address bits [31:20]. The
lower 20 bits of the address are assumed to be 0. The memory address range adheres to
1-Mbyte alignment and granularity.
3–0
Reserved
Reserved