SV: emulating RDTSC

[John B�ckstrand]

>Why emulating it anyway ? I don't think plex86 makes any sense on 
>"none pentium class"  PC's (performance!). Therefore the instruction 
>could be executed directly. However I'm not sure if a counter reset may 
>cause any harm to the (Linux)host.  
>Norbert 

because the plex86 machine might not run in native speed? And that would
be erronous (if you ask me) to use the real tsc, since it would make the
virtual machines clock seem to go too fast.

One thing that would definitely not work that nicely is programs that
try to check for optimal code, using RDTSC to time parts of the code.
This timing would be skewed by host load if one were to use the real tsc.