Datasheet

Errata
44 Specification Update
AE67. 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 Summary Tables of Changes
.
AE68. 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 Summary Tables of Changes
.