AMD K manual Preliminary Information

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Preliminary Information

23614K— October 2003

AMD Athlon™ Processor Model 4 Revision Guide

21 Real Mode RDPMC with Illegal ECX May Cause Unpredictable Operation

Products Affected. A4, A5, A6, A7, A9

Normal Specified Operation. Illegal values of ECX (that is, ECX>3) for the RDPMC (Read Performance Monitor Counter) instruction cause the processor to take a general protection exception.

Non-conformance.If the RDPMC is executed in real mode with a specific illegal value of ECX=4, then the processor may incorrectly enter the GP fault handler as if it were in 32-bit real mode.

Potential Effect on System. Incorrect instruction decode leading to unpredictable system failure.

Suggested Workaround. When in real mode, restrict use of the RDPMC instruction to legal counter values (0-3). This circumstance is not expected to occur in normal operation and has only been detected in a simulation environment.

Resolution Status. No fix planned.

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Contents Revision Guide Advanced Micro Devices, Inc AMD Athlon Processor Model 4 Revision Guide Revision HistoryRevision Guide Policy AMD Athlon Processor Model Revision GuideProduct Errata Products Affected. A4, A5, A6, A7, A9 Resolution Status. No fix plannedProducts Affected. A4, A5 Resistance Value of the ZN and ZP PinsPotential Effect on System. The system hangs Instruction Execution Deadlock Products Affected. A4, A5, A6, A7Suggested Workaround. None Potential Effect on System. The system will hang Products Affected. A9 Preliminary Information Resolution Status. No fix planned Preliminary Information Preliminary Information Potential Effect on System. System failure Single Step Across I/O SMI Skips One Debug Trap Kernel Workaround Software Prefetches May Report a Page FaultPreliminary Information Revision Determination Technical and Documentation Support
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