RDTSC
Usage: RDTSC Modifies flags: None
Read time-stamp counter into EDX:EAX.
Read Time-Stamp Counter
RDTSC ; 0F 31 [PENT]
RDTSC . Loads the current value of the processor's time-stamp counter into the EDX:EAX registers. The time-stamp counter is contained in a 64-bit MSR. The high-order 32 bits of the MSR are loaded into the EDX register, and the low-order 32 bits are loaded into the EAX register.
The processor monotonically increments the time-stamp counter MSR every clock cycle and resets it to 0 whenever the processor is reset.
EXAMPLE:
rdtsc