Errata
36
Intel
®
Core™2 Extreme Quad-Core Processor QX6000
Δ
Sequence and Intel
®
Core™2 Quad Processor Q6000
Δ
Sequence
Specification Update
Workaround:
Clear the AC flag (bit 18) in the EFLAGS register and/or the AM bit (bit 18) of
Control Register CR0 to disable alignment checking.
Status:
For the steppings affected, see the Summary Tables of Changes.
AK42.
Upper 32 Bits of the FPU Data (Operand) Pointer in the FXSAVE
Memory Image May Be Unexpectedly All 1s after FXSAVE
Problem:
The upper 32 bits of the FPU Data (Operand) Pointer may incorrectly be set
to all 1s instead of the expected value of all 0's in the FXSAVE memory image
if all of the following conditions are true:
•
The processor is in 64-bit mode.
•
The last floating point operation was in compatibility mode
•
Bit 31 of the FPU Data (Operand) Pointer is set.
•
An FXSAVE instruction is executed
Implication:
Software depending on the full FPU Data (Operand) Pointer may behave
unpredictably.
Workaround:
None identified.
Status:
For the steppings affected, see the Summary Tables of Changes.
AK43.
Concurrent Multi-processor Writes to Non-dirty Page May Result in
Unpredictable Behavior
Problem:
When a logical processor writes to a non-dirty page, and another logical-
processor either writes to the same non-dirty page or explicitly sets the dirty
bit in the corresponding page table entry, complex interaction with internal
processor activity may cause unpredictable system behavior.
Implication:
This erratum may result in unpredictable system behavior and hang.
Workaround:
It is possible for BIOS to contain a workaround for this erratum.
Status:
For the steppings affected, see the Summary Tables of Changes.
AK44.
Performance Monitor IDLE_DURING_DIV (18h) Count May Not be
Accurate
Problem:
Performance monitoring events that count the number of cycles the divider is
busy and no other execution unit operation or load operation is in progress
may not be accurate.
Implication:
The counter may reflect a value higher or lower than the actual number of
events.
Workaround:
None identified.
Status:
For the steppings affected, see the Summary Tables of Changes.