Actual source code: nt_time.c

  2: #include <petsc.h>
  3: #if defined (PETSC_USE_NT_TIME)
  4: #include <Windows.h>
  5: #define FACTOR   4294967296.0 /* pow(2,32) */

  9: PetscLogDouble nt_time(void)
 10: {
 11:   static PetscTruth     flag = PETSC_TRUE;

 14:   static LARGE_INTEGER  StartTime,PerfFreq,CurTime;
 15:   static PetscLogDouble SecInTick=0.0;
 16: 
 17:   DWORD                 dwStartHigh,dwCurHigh;
 18:   PetscLogDouble        dTime,dHigh;
 19:   PetscLogDouble        ptime;
 20: 
 21: 
 23:   if (flag) {
 24:     QueryPerformanceCounter(&StartTime);CHKERRQ(!ierr);
 25:     QueryPerformanceFrequency(&PerfFreq);CHKERRQ(!ierr);
 26:     /* Explicitly convert the higher 32 bits, and add the lower 32 bits from the counter */
 27:     /* works on non-pentium CPUs ? */
 28: #if defined(PETSC_HAVE_LARGE_INTEGER_U)
 29:     SecInTick = 1.0/((double)PerfFreq.u.HighPart*FACTOR+(double)PerfFreq.u.LowPart);
 30: #else
 31:     SecInTick = 1.0/((double)PerfFreq.HighPart*FACTOR+(double)PerfFreq.LowPart);
 32: #endif
 33:     flag = PETSC_FALSE;
 34:   }
 35: 
 36:   QueryPerformanceCounter(&CurTime);CHKERRQ(!ierr);
 37: #if defined(PETSC_HAVE_LARGE_INTEGER_U)
 38:   dwCurHigh   = (DWORD)CurTime.u.HighPart;
 39:   dwStartHigh = (DWORD)StartTime.u.HighPart;
 40: #else
 41:   dwCurHigh   = (DWORD)CurTime.HighPart;
 42:   dwStartHigh = (DWORD)StartTime.HighPart;
 43: #endif
 44:   dHigh       = (signed)(dwCurHigh - dwStartHigh);

 46: #if defined(PETSC_HAVE_LARGE_INTEGER_U)
 47:   dTime = dHigh*(double)FACTOR + (double)CurTime.u.LowPart - (double)StartTime.u.LowPart;
 48: #else
 49:   dTime = dHigh*(double)FACTOR + (double)CurTime.LowPart - (double)StartTime.LowPart;
 50: #endif
 51:   /* Use the following with older versions of the Borland compiler
 52:   dTime = dHigh*(double)FACTOR + (double)CurTime.u.LowPart - (double)StartTime.u.LowPart;
 53:   */
 54:   ptime = (double)SecInTick*dTime;

 56:   PetscFunctionReturn(ptime);
 57: }
 58: #endif