AMD K manual Potential Effect on System. System failure

Preliminary Information

AMD Athlon™ Processor Model 4 Revision Guide 23614K —October 2003

22 Using Task Gates With Breakpoints Enabled May Cause Unexpected Faults

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

Normal Specified Operation. Task gates should correctly use the TSS selector out of the task gate for CALL and JMP instructions.

Non-conformance.When a task gate is used by a CALL or JMP instruction and any debug breakpoint is enabled through the DR7.LE or GE bits, the processor may, under certain timing scenarios, incorrectly use the new TSS base[15:0] contained in the new TSS as a selector. This will most likely cause a GP fault with an error code of the new TSS base.

Potential Effect on System. System failure.

Suggested Workaround. When using software that uses task gates with CALL or JMP instructions, do not enable breakpoints.

Resolution Status. No fix planned.

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