
System Address Map
R
Figure 4. DOS Compatible Area Address Map
  | 0C0000h  | |
Standard PCI/ISA  | 0B8000h  | |
  | ||
Video Memory  | 0B0000h  | |
(SMM Memory)  | ||
  | ||
  | 0A0000h  | 
Upper, Lower,
Expansion Card BIOS
and Buffer Area
Monochrome Display
Adapter Space
1 MB
  | Controlled by  | 
  | PAM[6:0]  | 
768 KB  | 
  | 
736 KB  | Controlled by  | 
  | VGA Enable and  | 
704 KB  | MDA Enable  | 
  | |
640 KB  | 
  | 
= Optional AGP
= Optional System Memory
= System Memory
sys_addr_map_2
Figure 5. Extended Memory Range Address Map
  | 
  | 
  | 1_0000_0000 (4 GB)  | ||
  | High BIOS, Optional  | 
  | |||
  | 
  | 
  | 
  | 
  | |
  | extended SMRAM  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | FF00_0000  | ||
  | Hub Interface  | 
  | |||
  | 
  | 
  | 
  | 
  | |
  | (always)  | 
  | FEF0_0000  | ||
  | 
  | 
  | |||
  | Local APIC Space  | 
  | |||
  | 
  | 
  | 
  | 
  | |
  | 
  | 
  | FEE0_0000  | ||
  | Hub Interface  | 
  | |||
  | 
  | 
  | 
  | 
  | |
  | (always)  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | FED0_0000  | ||
  | I/O APIC Space  | 
  | |||
  | 
  | 
  | 
  | 
  | |
  | 
  | 
  | FEC8_0000  | ||
  | I/O APIC Space  | 
  | |||
  | 
  | 
  | 
  | 
  | |
  | 
  | 
  | FEC0_0000  | ||
  | AGP/PCI  | 
  | |||
  | 
  | 
  | 
  | 
  | |
  | 
  | 
  | Top of Low Memory (TOM)  | ||
  | Extended SMRAM  | 
  | |||
  | 
  | 
  | 
  | 
  | |
  | Space  | 
  | TEM - TSEG | ||
  | 
  | 
  | |||
  | 
  | 
  | 100C_0000  | ||
  | Extended SMRAM  | 
  | |||
  | 
  | 
  | 
  | 
  | |
  | (translated to < 1 MB)  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 100A_0000  | ||
  | 
  | 
  | |||
  | 
  | 
  | 0100_0000 (16 MB)  | ||
  | ISA Hole  | 
  | |||
  | 
  | 
  | 
  | = System Memory Region  | |
  | 
  | 
  | 
  | ||
  | 
  | 
  | 00F0_0000 (15 MB)  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | = Optional System Memory Region  | 
  | 
  | 
  | 
  | 
  | |
  | 
  | 
  | 0010_0000 (1 MB)  | 
  | 
  | 
  | 
  | 
  | |||
  | 
  | 
  | 
  | 
  | sys_addr_map_3  | 
  | 
  | 
  | 
  | 
  | 
  | 
98  | Intel® 82845 MCH for SDR Datasheet |