Errata
Specification Update
39
AN65.
A Thermal Interrupt Is Not Generated When the Current Temperature
Is Invalid
Problem:
When the DTS (Digital Thermal Sensor) crosses one of its programmed thresholds it
generates an interrupt and logs the event (IA32_THERM_STATUS MSR (019Ch) bits
[9,7]). Due to this erratum, if the DTS reaches an invalid temperature (as indicated
IA32_THERM_STATUS MSR bit[31]) it does not generate an interrupt even if one of
the programmed thresholds is crossed and the corresponding log bits become set.
Implication:
When the temperature reaches an invalid temperature the CPU does not generate a
Thermal interrupt even if a programmed threshold is crossed.
Workaround:
None identified.
Status:
For the steppings affected, see the
AN66.
Performance Monitoring Event FP_ASSIST May Not Be Accurate
Problem:
Performance monitoring event FP_ASSIST (11H) may be inaccurate as assist events
will be counted twice per actual assist in the following specific cases:
•
FADD and FMUL instructions with a not a Number (NaN) operand and a memory
operand.
•
FDIV instruction with zero operand value in memory
In addition, an assist event may be counted when DAZ (Denormals-Are-Zeros) and
FTZ (Flush-To-Zero) flags are turned on even though no actual assist occurs.
Implication:
The counter value for performance monitoring event FP_ASSIST (11H) may be larger
than expected. The size of the error is dependent on the number of occurrences of the
above condition while the event is active.
Workaround:
None identified.
Status:
For the steppings affected, see the
AN67.
The BS Flag in DR6 May Be Set for Non-Single-Step #DB Exception
Problem:
DR6 BS (Single Step, bit 14) flag may be incorrectly set when the TF (Trap Flag, bit 8)
of the EFLAGS Register is set and a #DB (Debug Exception) occurs due to one of the
following:
•
DR7 GD (General Detect, bit 13) being bit set;
•
INT1 instruction;
•
Code breakpoint
Implication:
The BS flag may be incorrectly set for non-single-step #DB exception.
Workaround:
None identified.
Status:
For the steppings affected, see the
