Errata
50
Intel
®
Core™2 Extreme Quad-Core Processor QX6000
Δ
Sequence and Intel
®
Core™2 Quad Processor Q6000
Δ
Sequence
Specification Update
Status:
For the steppings affected, see the Summary Tables of Changes.
AK85.
Non-Temporal Data Store May be Observed in Wrong Program Order
Problem:
When non-temporal data is accessed by multiple read operations in one
thread while another thread performs a cacheable write operation to the
same address, the data stored may be observed in wrong program order (i.e.
later load operations may read older data).
Implication:
Software that uses non-temporal data without proper serialization before
accessing the non-temporal data may observe data in wrong program order.
Workaround:
Software that conforms to the Intel
®
64 and IA-32 Architectures Software
Developer's Manual, Volume 3A, section “Buffering of Write Combining
Memory Locations” will operate correctly.
Status:
For the steppings affected, see the Summary Tables of Changes.
AK86.
Performance Monitor SSE Retired Instructions May Return Incorrect
Values
Problem:
Performance Monitoring counter SIMD_INST_RETIRED (Event: C7H) is used
to track retired SSE instructions. Due to this erratum, the processor may
inaccurately also count certain other types of instructions resulting in higher
than expected values.
Implication:
Performance Monitoring counter SIMD_INST_RETIRED may report count
higher than expected.
Workaround:
None identified.
Status:
For the steppings affected, see the Summary Tables of Changes.
AK87.
Fault on ENTER Instruction May Result in Unexpected Values on Stack
Frame
Problem:
The ENTER instruction is used to create a procedure stack frame. Due to this
erratum, if execution of the ENTER instruction results in a fault, the dynamic
storage area of the resultant stack frame may contain unexpected values (i.e.
residual stack data as a result of processing the fault).
Implication:
Data in the created stack frame may be altered following a fault on the
ENTER instruction. Please refer to “Procedure Calls For Block-Structured
Languages” in
IA-32 Intel
®
Architecture Software Developer’s Manual, Vol. 1,
Basic Architecture
, for information on the usage of the ENTER instructions.
This erratum is not expected to occur in ring 3. Faults are usually processed
in ring 0 and stack switch occurs when transferring to ring 0. Intel has not
observed this erratum on any commercially available software.
Workaround:
None identified.
Status:
For the steppings affected, see the Summary Tables of Changes.