Error Case Summary - Compaq EV68A Hardware Reference Manual

Error Case Summary

8.13 Error Case Summary

Table 8–3 summarizes the various error cases and their ramifications.
Table 8–3 Error Case Summary
Error Exception Status
Icache data or tag CRD
parity error
Dcache tag parity DFAULT
error (on issue)
Dcache tag parity MCHK
error (on retry)
Dcache single-bit CRD
ECC error on load
Dcache single-bit CRD
ECC error on
speculative load
Dcache single-bit CRD
ECC error on small
store
Dcache single-bit None
ECC error on victim
read
Dcache second error MCHK
on store
Dcache duplicate tag MCHK
parity error
Bcache tag parity MCHK
error
Bcache single-bit MCHK
error on Icache fill and CRD
Bcache single-bit CRD
error on Dcache fill
Bcache victim read CRD
on Dcache/Bcache
miss
Bcache victim read None
on ECB
Error Detection and Error Handling
8–10
ISTAT[PAR]
MM_STAT[DC_TAG_PERR]
VA[address]
1
DC_STAT[TPERR_P0] or
DC_STAT[TPERR_P1]
DC_STAT[ECC_ERR_LD]
C_STAT[DSTREAM_DC_ERR]
C_ADDR[bits [19:6] of the error
address. [42:20] not updated.]
DC_STAT[ECC_ERR_LD]
C_STAT contains zero
DC_STAT[ECC_ERR_ST]
None
1
DC_STAT[SEO]
1
C_STAT[DC_PERR]
C_ADDR[error address]
1
C_STAT[BC_PERR]
C_ADDR[error address]
C_STAT[ISTREAM_BC_ERR]
2
C_ADDR[error address]
C_SYNDROME_0
C_SYNDROME_1
DC_STAT[ECC_ERR_LD]
C_STAT[DSTREAM_BC_ERR]
C_ADDR[error address]
C_SYNDROME_0
C_SYNDROME_1
DC_STAT[ECC_ERR_LD]
C_STAT contains 0
None
Hardware
Action PALcode Action
Icache flushed Log as CRD
— Evict with two
HW_LDs and log as
CRD
— Log as MCHK
Corrected and Log as CRD
scrubbed
None Log as CRD
Corrected and Log as CRD
scrubbed
Corrected and None
scrubbed
No correction Log as MCHK
on either store
Uncorrectable Log as MCHK
Uncorrectable Log as MCHK
Icache flushed Scrub error as described
in
Log as CRD
Corrected and Scrub error as described
scrubbed in in
3
Dcache Log as CRD
None Log as CRD
None None
21264/EV68A Hardware Reference Manual
Section D.36
.
Section D.36
.