__rdtscp
Microsoft Specific
Generates the rdtscp instruction, writes TSC_AUX[31:0] to memory, and returns the 64-bit Time Stamp Counter (TSC) result.
unsigned __int64 __rdtscp( unsigned int * Aux );
This intrinsic generates the rdtscp instruction. To determine hardware support for this instruction, call the __cpuid intrinsic with InfoType=0x80000001 and check bit 27 of CPUInfo[3] (EDX). This bit is 1 if the instruction is supported, and 0 otherwise. If you run code that uses this intrinsic on hardware that does not support the rdtscp instruction, the results are unpredictable.
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Unlike rdtsc, rdtscp is a serializing instruction; nevertheless, the compiler can move code around this intrinsic. |
The interpretation of the TSC value in this generation of hardware differs from that in earlier versions of x64. See hardware manuals for more information.
The meaning of the value in TSC_AUX[31:0] depends on the operating system.
Caution: