AMD Athlon 6 Dokumentacja Pobierz pdf (Strona 69)

Product Errata 69

Revision Guide for AMD Athlon™ 64 and AMD Opteron™ Processors

25759 Rev. 3.79 July 2009

109 Certain Reverse REP MOVS May Produce Unpredictable

Behavior

Description

In certain situations a REP MOVS instruction may lead to incorrect results. An incorrect address size,

data size or source operand segment may be used or a succeeding instruction may be skipped. This

may occur under the following conditions:

• EFLAGS.DF=1 (the string is being moved in the reverse direction).

• The number of items being moved (RCX) is between 1 and 20.

• The REP MOVS instruction is preceded by some microcoded instruction that has not completely

retired by the time the REP MOVS begins execution. The set of such instructions includes

BOUND, CLI, LDS, LES, LFS, LGS, LSS, IDIV, and most microcoded x87 instructions.

Potential Effect on System

Incorrect results may be produced or the system may hang.

Suggested Workaround

Contact your AMD representative for information on a BIOS update.

Fix Planned

Yes

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AMD Athlon 6 Dokumentacja Strona 69