System Memory Address Space - Intel 460GX Software Developer’s Manual

System Address Map
Figure 4-1. System Memory Address Space
(16 TB-4GB)
(4 GB-16MB)
15 MB
1 MB
4.1.1.4 System Firmware
The 64 KB region from F_0000h to F_FFFFh is treated as a single block. Read/Write attribute
enables defined in the MAR registers may be used to direct accesses to the compatibility PCI bus
or main memory. At power-on, this area is mapped by default to the PCI compatibility bus.
4-2
FFF_FFFF_FFFF
High
Extended
1_0000_0000
Memory
Medium
Extended
memory
Low
Extended
Memory
10_0000
Compatibility
Area
Areas are not
drawn to scale.
System
Memory
Firmware,
32
Processor &
Chipset
MB
Specific
System
Memory
System
64K
Firmware
F_0000
C, D, and E
192K
Segments
C_0000
128K
VGA
Memory
A_0000
512K-640K
DOS
Region
640K
0
Intel® 460GX Chipset Software Developer's Manual
FFFF_FFFF
High
System
Firmware
FF00_0000
Processor
Specific
FEC0_0000
Chipset
Specific
FE00_0000
n x 32M
PCI Gaps
FE00_0000 -
(n x 32M)
16 MB
4 MB
12 MB