Re: CPU time for Win32 & GNAT

["Pat Rogers" <progers@classwide.com>]

"Gautier" <gautier_niouzes@hotmail.com> wrote in message
news:17cd177c.0110120321.3077bccf@posting.google.com...
> Hi!
>
> Does someone know how to obtain the CPU time (or a CPU
> duration...) for Win32 (under GNAT) in a simple way ?
> The program doesn't use tasking and no more resolution
> than the one of Duration is needed for time spans.
> I'm sure someone has a ready-made function in his/her toolbox...

Better yet, why not use the Pentium ReadTimeStampCounter (RDTSC)
instruction?  It samples the register that keeps a count of the number of
clock cycles since boot-up.  Given the exact clock speed you can compute
exactly how much time has elapsed between two samples.


with Interfaces;

package Pentium_Cycle_Counter is

  pragma Suppress( All_Checks );

  type Count is new Interfaces.Unsigned_64;

  function Sample return Count;

  pragma Inline( Sample );

end Pentium_Cycle_Counter;


with Machine_Code;

package body Pentium_Cycle_Counter is

  use Machine_Code;

  function Sample return Count is
    Result : Count;
  begin
    Asm( "RDTSC", Count'Asm_Output("=A",Result), Volatile => True );
    return Result;
  end Sample;

end Pentium_Cycle_Counter;


---
Patrick Rogers                       Consulting and Training in:
http://www.classwide.com          Real-Time/OO Languages
progers@classwide.com               Hard Deadline Schedulability Analysis
(281)648-3165                                 Software Fault Tolerance