
82815 GMCH
R
Datasheet
109
3.6.13.
GMADR—Graphics Memory Range Address Register
(Device 2)
Address Offset:
10
13h
Default Value:
00000008h
Access:
Read/Write, Read-Only
Size:
32 bits
This register requests allocation for the GMCH graphics memory. The allocation is for either 32 MB or
64 MB of memory space (selected by bit 0 of the Device 0 MISCC Register) and the base address is
defined by bits [31:25,24].
31
26
25
24
16
Memory Base Address
64 MB
Addr. Mask
Address Mask
(HW=0; 32MB addr range)
15
4
3
2
1
0
Address Mask (cont)
(HW=0; 32MB addr range)
Prefetch
Mem En
(HW=1)
Memory Type
(HW=0; 32MB addr)
Mem/IO
Space
(HW=0)
Bit
Description
31:26
Memory Base Address
[31:26].
R/W.
Set by the operating system, these bits correspond to address signals
25
64 MB Address Mask
RO , R/W.
64 MB = If Device 0 MISCC Reg bit 0 = 0, then this bit is read-only with a value of 0, indicating a
memory range of 64 MB.
32 MB = If Device 0 MISCC Reg bit 0 = 1, this bit is R/W, indicating a memory range of 32 MB.
24:4
Address Mask
RO.
Hardwired to 0s to indicate 32 MB address range.
3
Prefetchable Memory
RO.
Hardwired to 1 to enable prefetching.
2:1
Memory Type
RO.
Hardwired to 0 to indicate 32-bit address.
0
Memory/IO Space
RO.
Hardwired to 0 to indicate memory space.