Datasheet

Datasheet 89

Video Buffer Area (A0000h–BFFFFh)

Attribute Bits do not control this 128-kB area. The Host-initiated cycles in this region are always

forwarded to either PCI0 or PCI2 unless this range is accessed in SMM mode. Routing of

accesses is controlled by the Legacy VGA Control Mechanism of the “Virtual” PCI-PCI Bridge

Device embedded within the GMCH.

This area can be programmed as SMM area via the SMRAM register. When used as an SMM

space, this range can not be accessed from the hub interface.

Expansion Area (C0000h–DFFFFh)

This 128-kB area is divided into eight 16-kB segments that can be assigned with different

attributes via PAM Control register as defined in Table 31 and Figure 6.

Extended System BIOS Area (E0000h–EFFFFh)

This 64-kB area is divided into four 16-kB segments that can be assigned with different attributes

via PAM Control register as defined in Table 31 and Figure 6.

System BIOS Area (F0000h–FFFFFh)

This area is a single 64-kB segment that can be assigned with different attributes via PAM

Control register as defined in Table 31 and Figure 6.