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IBM21P100BGC
IBM 133 PCI-X Bridge R2.0
Configuration Registers
ppb20_pcix_regs.fm.01
October 15, 2001
5.2.4.22 Prefetchable Memory Base Register
This register specifies the base of the prefetchable memory address range bits 31:20 and is used in conjunc-
tion with the prefetchable memory limit register, the prefetchable base upper 32 bits register, and the
prefetchable limit upper 32 bits register to specify a range of 64-bit addresses supported for prefetchable
memory transactions on the PCI bus. Address bits 19:0 are assumed to be x‘0 0000’ for the base address.
This register also specifies that the bridge supports 64-bit prefetchable memory addressing.
5.2.4.23 Prefetchable Memory Limit Register
This register specifies the upper address of the prefetchable memory address range bits 31:20 and is used in
conjunction with the prefetchable memory base register, the prefetchable base upper 32 bits register, and the
prefetchable limit upper 32 bits register to specify a range of 64-bit addresses supported for prefetchable
memory transactions on the PCI bus. Address bits 19:0 are assumed to be x‘FFFFF’ for the limit address.
This register also specifies that the bridge supports 64-bit prefetchable memory addressing.
Address Offset
x‘24’
Access
See individual fields
Reset Value
x‘8001’
Prefetchable Memory Base Address
64-Bit
Addressing
15 14 13 12 11 10
9
8
7
6
5
4
3
2
1
0
Bit(s)
Access
Field Name and Description
15:4
RW
Prefetchable Memory Base Address
Address bits 31:20 of the base address for the address range of prefetchable memory operations that are
passed from the primary to the secondary PCI bus.
3:0
RO
64-bit addressing. Set to b‘0001’ to indicate support of 64-bit addressing.
Address Offset
x‘26’
Access
See individual fields
Reset Value
x‘0001’
Prefetchable Memory Limit Address
64-Bit
Addressing
15 14 13 12 11 10
9
8
7
6
5
4
3
2
1
0
Bit(s)
Access
Field Name and Description
15:4
RW
Prefetchable Memory Limit Address
Address bits 31:20 of the limit address for the address range of prefetchable memory operations that are
passed from the primary to the secondary PCI bus.
3:0
RO
64-bit addressing. Set to b‘0001’ to indicate support of 64-bit addressing.