Ultrasparc Data Buffer (Udb) Control Register; Overwrite Policy - Sun Microsystems UltraSPARC-I User Manual

11.4 UltraSPARC Data Buffer (UDB) Control Register

Name: ASI_UDBH_CONTROL_REG_WRITE
ASI=77
16
Name: ASI_UDBH_CONTROL_REG_READ
ASI=7F
16
Name: ASI_UDBL_CONTROL_REG_WRITE
ASI=77
16
Name: ASI_UDBL_CONTROL_REG_READ
ASI=7F
16
Table 11-8 UDB Error Register Format
Bits
<63:13> Reserved
<12:9> VERSION
<8> F_MODE
<7:0> FCBV
VERSION: 4-bit mask set revision number for the selected UDB chip.
F_MODE: If set, the contents of the FCBV field are sent with the out-going
transaction, instead of the generated ECC.
FCBV: Force check bit vector.

11.5 Overwrite Policy

This section describes the overwrite policy for error bits when multiple errors
conditions have occurred. Errors are captured in the order that they are detected,
not necessarily in program order.
If an error occurs at the same time as error bits are cleared by software, then the
overwrite control will include the effect of the software clear. For example, if ETP
was set (which blocks E-Cache tag syndrome updates) and software clears the
ETP bit at the same time as an E-Cache tag parity error occurs, the E-Cache tag
syndrome will be updated.
11.5.1 AFAR Overwrite Policy
Priority for AFAR updates: UE > CE > {TO, BE}
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, VA<63:0>=20
16
, VA<63:0>=20
16
, VA<63:0>=38
16
, VA<63:0>=38
16
Field Use
—
UDB version number
Force ECC error
Force check bit vector
11. Error Handling
RW
R
R
RW
RW
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