RDTSCP from dlang

[kookman via Digitalmars-d-learn]

On Tuesday, 30 August 2016 at 09:04:41 UTC, Basile B. wrote:
> ALternatively to Rikki K's solution, you can do this to mimic 
> the rdtscp behavior:
>
> asm
> {
>   cpuid;
>   rdtsc;
>   // store time in locals
> }
> // bench
> {
>   rdtsc;
>   // store time in locals
> }
> // compute delta
>
>
> explanations here:
> - 
> http://www.intel.com/content/dam/www/public/us/en/documents/white-papers/ia-32-ia-64-benchmark-code-execution-paper.pdf
> - http://stackoverflow.com/a/14214220
>
> But according to the first link, this solution, while better 
> than rdtsc alone, is not as good as rdtscp.

Indeed, I want to use rdtscp to get access to the core ID it 
makes available (to at least know when tsc is from different 
cores/packages). I guess in the meantime I can use Rikki's 
solution.

Sorry I'm a DMD asm newbie: DO i need to worry about which 
registers I clobber here? I couldn't find any info about this on 
the Inline Assembly doco page on dlang.org.