REP Prefix Warning

REP_Prefix is a warning that is issued during static analysis mode.

The instruction for which REP_Prefix is issued operates on a string, and has a REP prefix. When REP precedes a string instruction, the instruction is repeated the number of times indicated in the count register (ECX/CX).

During static analysis, the VTune(TM) Performance Analyzer assumes that the value indicated in the count register is 1, and specifies the number of execution cycles accordingly. For example, during static analysis, the VTune analyzer indicates that REP MOVS executes in thirteen cycles.

Refer to the description on REP in Chapter 25 of the Pentium(R) Processor User's Manual, Volume 3 for more information on execution cycles.