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5–58
Internal Processor Registers
29 September 1997 – Subject To Change
External Interface Control (CBU) IPRs
5.3 External Interface Control (CBU) IPRs
Table 5–25 lists specific IPRs for controlling Bcache, system configuration, and log-
ging error information. These IPRs cannot be read or written from the system. They
are placed in the 1MB region of 21164PC-specific I/O address space ranging from
FF FFF0 0000 to FF FFFF FFFF. Any read or write operation to an undefined IPR in
this address space produces UNDEFINED behavior. The operating system should
not map any address in this region as writable in any mode.
The CBU internal processor registers are described in Section 5.3.1 through
Section 5.3.4.
Table 5–25 CBU Internal Processor Register Descriptions
Register
Address
Type
Description
CBOX_CONFIG
FF FFF0 0008
RW
Contains Bcache configuration parameters.
CBOX_ADDR
FF FFF0 0088
R
Contains the address for Bcache/system-
related errors.
CBOX_STATUS
FF FFF0 0108
R
Contains system-to-CPU clock ratio, chip-
ID information, and logs Bcache/system-
related errors.
CBOX_CONFIG2
FF FFF0 0188
RW
Contains additional Bcache configuration
parameters.