Specification Update

Errata
40 Specification Update
AM64 BTM/BTS Branch-From Instruction Address May be Incorrect for Software
Interrupts
Problem: When BTM (Branch Trace Message) or BTS (Branch Trace Store) is enabled, a
software interrupt may result in the overwriting of BTM/BTS branch-from instruction
address by the LBR (Last Branch Record) branch-from instruction address.
Implication: A BTM/BTS branch-from instruction address may get corrupted for software interrupts.
Workaround: None identified.
Status: For the steppings affected, see the Summary Tables of Changes.
AM65 Performance Monitor SSE Retired Instructions May Return Incorrect Values
Problem: The SIMD_INST_RETIRED (Event: C7H) is used to track retired SSE instructions. Due
to this erratum, the processor may inaccurately count certain types of instructions
resulting in values higher than the number of actual retired SSE instructions.
Implication: The event monitor instruction SIMD_INST_RETIRED may report count higher than
expected.
Workaround: None identified.
Status: For the steppings affected, see the Summary Tables of Changes.
AM66 REP Store Instructions in a Specific Situation may cause the Processor to
Hang
Problem: During a series of REP (repeat) store instructions a store may try to dispatch to
memory prior to the actual completion of the instruction. This behavior depends on
the execution order of the instructions, the timing of a speculative jump and the
timing of an uncacheable memory store. All types of REP store instructions are
affected by this erratum.
Implication: When this erratum occurs, the processor may live lock and/or result in a system
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.