Accelerated Graphics Port Interface Specification

AGP3.0 Interface Specification
Rev. 1.0
138
Bits Access Field Description
0 RZ-IW Memory Hardwired to zero to indicate that the Graphics AGP3.0
aperture must reside in “Memory” space – as defined by the
PCI Local Bus Specification.
5.9.2 APBASEHI: AGP APERTURE BASE ADDRESS HIGH REGISTER
This register is only available when AGPSTAT.over4G bit is set. . When the AGPSTAT.over4G bit is not
set, reads to this register will return undefined data and writes will have no effect.
Offset: 14h
Size: 4 bytes
Table 69: Base Address
Bits Access Field Description
31:0 R-W-D’0 AddressHi Address[63:32] of the AGP aperture address. Used only if
APBASELO[2:1] select a 64-bit Base Address Register;
otherwise this register is ignored.