250
Recommended BIOS Settings
Chapter 7
AMD-761™ System Controller Software/BIOS Design Guide
24081D—February 2002
Preliminary Information
Registers
-----
Bits
Description
Initialized/
Required
Value
Actual
Value
Key
fcn( )
Notes
0x1x0x20h
AGP/PCI Memory Limit and Base
31:20
MLim[31:20]
xxxh
B
Memory Limit Address
defining top address to be
used by AGP target graphics
controller for control
registers and buffers. The
lower 20 bits are 0xFFFFF
for 1-Mbyte granularity.
19:16
Reserved
0h
r
15:4
MBase[31:20]
xxxh
B
Memory Limit Address
defining lower address to be
used by AGP target graphics
controller for control
registers and buffers. The
lower 20 bits are 0xFFFFF
for 1-Mbyte granularity.
3:0
Reserved
0h
r
0x1x0x24h
AGP/PCI Prefetchable
Memory Limit and Base
31:20
MLim [31:20]
xxxh
B
Prefetchable Memory Limit
Address defining top address
to be used by AGP target
graphics controller for control
registers and buffers. The
lower 20 bits are 0xFFFFF for
1-Mbyte granularity.
19:16
0h
r
15:4
MBase [31:20]
xxxh
B
Prefetchable Memory Base
Address defining lower
address to be used by AGP
target graphics controller for
control registers and buffers.
The lower 20 bits are 0xFFFFF
for 1-Mbyte granularity.
3:0
Reserved
0h
r
KEY:
B= Mandatory BIOS function
A= AGP setup by BIOS
c = Calculated/set by AMD-761™ internal logic
P= Power management setup by BIOS
o = Setup by OS or OS driver
F = Performance enhancement set by BIOS
r = Hardcoded and reserved
u = PCI operational user interface
E = Elective BIOS function