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IBM21P100BGB
IBM 133 PCI-X Bridge R1.1
ppb11_pcix_regs.fm.03
July 9, 2001
Configuration Registers
Page 49 of 131
5.2.4.21 Prefetchable Memory Base Register
The Prefetchable Memory Base register specifies the base of the prefetchable memory address range bits
31:20 and is used in conjunction 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.
5.2.4.22 Prefetchable Memory Limit Register
The Prefetchable Memory Limit 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‘F FFFF’ 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‘XXX1’
Prefetchable Memory Base Address
64-Bit
Addressing
15 14 13 12 11 10
9
876543210
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‘XXX1’
Prefetchable Memory Limit Address
64-Bit
Addressing
15 14 13 12 11 10
9
876543210
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.