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C-/C++-Quelltext

#include <windows.h>
#include <tchar.h>
#include <lmaccess.h>    // wegen NTSTATUS

#include <stdio.h>

typedef LRESULT (WINAPI * CALLNTPOWERINFORMATION)(POWER_INFORMATION_LEVEL, PVOID, 
                 ULONG, PVOID, ULONG);

typedef struct _PROCESSOR_POWER_INFORMATION {
    ULONG                   Number;
    ULONG                   MaxMhz;
    ULONG                   CurrentMhz;
    ULONG                   MhzLimit;
    ULONG                   MaxIdleState;
    ULONG                   CurrentIdleState;
} PROCESSOR_POWER_INFORMATION, *PPROCESSOR_POWER_INFORMATION;

#ifdef __BORLANDC__
  #define EMIT   db
#else
  #define EMIT   __emit
#endif

#if defined(__cplusplus) && !defined(INLINE)
  #define INLINE inline
#else
  #define INLINE
#endif

INLINE UINT64 rdtsc(VOID)
{
    _asm EMIT 0x0F
    _asm EMIT 0x31
}

UINT_PTR GetCpuSpeed(VOID)
{
  PROCESSOR_POWER_INFORMATION ppi;
  CALLNTPOWERINFORMATION      pfn;
  LARGE_INTEGER               liFreq, li1, li2;
  HINSTANCE                   hDll;
  NTSTATUS                    stat;
  UINT_PTR                    uSpeed;
  UINT64                      timestamp;
  HANDLE                      hThread;
  int                         nPriority;

    ZeroMemory(&ppi, sizeof(ppi));
    stat = ERROR_CALL_NOT_IMPLEMENTED;

    if(NULL != (hDll = LoadLibrary(TEXT("powrprof.dll"))))
    {
        if(NULL != (pfn = (CALLNTPOWERINFORMATION)GetProcAddress(hDll, 
                           "CallNtPowerInformation")))
        {
            stat = pfn(ProcessorInformation, NULL, 0, &ppi, sizeof(ppi));
        }
        FreeLibrary(hDll);
    }

    if(ERROR_SUCCESS == stat)
        return(ppi.CurrentMhz);

    hThread   = GetCurrentThread();
    nPriority = GetThreadPriority(hThread);

    QueryPerformanceFrequency(&liFreq);
    liFreq.QuadPart /= 10;
    SetThreadPriority(hThread, THREAD_PRIORITY_HIGHEST);

    timestamp = rdtsc();
    QueryPerformanceCounter(&li1);

    do
    {
        QueryPerformanceCounter(&li2);
    } while((li2.QuadPart - li1.QuadPart) < liFreq.QuadPart);

    uSpeed = (UINT_PTR)((rdtsc() - timestamp) / 100000);
    SetThreadPriority(hThread, nPriority);

  return(uSpeed);
}

int WINAPI _tWinMain(HINSTANCE, HINSTANCE, LPTSTR, int)
{
  TCHAR szSpeed[128];

    wsprintf(szSpeed, TEXT("CPU-Speed: ~%uMHz\n"), GetCpuSpeed());
    MessageBox(NULL, szSpeed, NULL, MB_OK);

  return(0);
}