QG82945GSE S LB2R Intel, QG82945GSE S LB2R Datasheet - Page 322

• Manufacturer Part Number: QG82945GSE S LB2R
• Description: GRAPHICS AND MEM CNTRL HUB; No. of Pins: 998; Package / Case: FCBGA; Interface Type: PCI, SATA, USB
• Manufacturer: Intel

Figure 11.
9.1.1
9.1.2
322
DOS Legacy Address Range
DOS Range (0h – 9_FFFFh)
The DOS area is 640 KB (0000_0000h – 0009_FFFFh) in size and is always mapped to
the main memory controlled by the (G)MCH.
Legacy Video Area (A_0000h-B_FFFFh)
The legacy 128-KB VGA memory range, frame buffer, (000A_0000h – 000B_FFFFh) can
be mapped to IGD (Device 2), to PCI Express (Device 1), and/or to the DMI. The
appropriate mapping depends on which devices are enabled and the programming of
the VGA steering bits. Based on the VGA steering bits, priority for VGA mapping is
constant. The (G)MCH always decodes internally mapped devices first. Internal to the
(G)MCH, decode precedence is always given to IGD. The (G)MCH always positively
decodes internally mapped devices, namely the IGD and PCI Express. Subsequent
decoding of regions mapped to PCI Express or the DMI depends on the Legacy VGA
configuration bits (VGA Enable and MDAP). This region is also the default for SMM
space.
000D_FFFFh
000E_FFFFh
000B_FFFFh
0000_0000h
000F_FFFFh
0009_FFFFh
000E_0000h
000C_0000h
000A_0000h
000F_0000h
Extended System BIOS (Lower)
System BIOS (Upper)
Legacy Video Area
128KB (16KBx8)
Expansion Area
64KB (16KBx4)
(SMM Memory)
DOS Area
128KB
64KB
1MB
960KB
896KB
768KB
640KB
System Address Map
Datasheet