ExAcquireFastMutex

VOID *__stdcall ExAcquireFastMutex(PFAST_MUTEX FastMutex){
  __int64 v1; 
  _ETHREAD *CurrentThread; 
  unsigned __int8 AbEntrySummary; 
  __int64 v5; 
  NTSTATUS SessionId; 
  bool v7; 
  unsigned __int8 CurrentIrql; 
  VOID *result; 
  unsigned __int8 AbOrphanedEntrySummary; 
  UINT64 a3; 

  v1 = 0i64;
  LODWORD(a3) = 0;
  CurrentThread = (_ETHREAD *)KeGetCurrentThread();
  --CurrentThread->Tcb.SpecialApcDisable;
  if( ++CurrentThread->Tcb.AbAllocationRegionCount != 1 )
    KeBugCheckEx(0x192u, CurrentThread, FastMutex, (PVOID)KeGetCurrentIrql(), 0i64);
  AbEntrySummary = CurrentThread->Tcb.AbEntrySummary;
  if( !AbEntrySummary )
  {
    if( !CurrentThread->Tcb.AbOrphanedEntrySummary )
      goto LABEL_18;
    AbOrphanedEntrySummary = CurrentThread->Tcb.AbOrphanedEntrySummary;
    CurrentThread->Tcb.AbOrphanedEntrySummary = 0;
    AbEntrySummary = AbOrphanedEntrySummary | CurrentThread->Tcb.AbEntrySummary;
  }
  _BitScanForward((unsigned int *)&v5, AbEntrySummary);
  CurrentThread->Tcb.AbEntrySummary = AbEntrySummary & ~(1 << v5);
  v1 = (__int64)&CurrentThread->Tcb.LockEntries[v5];
  if( !v1 )
  {
LABEL_18:
    _interlockedbittestandset((volatile signed __int32 *)&CurrentThread->Tcb.116 + 1, 0x10u);
    goto LABEL_8;
  }
  if( (unsigned __int64)FastMutex >= 0xFFFF800000000000ui64
    && *((_BYTE *)&stru_140C4DB30 + (((unsigned __int64)FastMutex >> 39) & 0x1FF) + 6872) == 1 )
  {
    SessionId = MmGetSessionIdEx(CurrentThread->Tcb.ApcState.Process);
  }
  else
  {
    SessionId = -1;
  }
  *(_DWORD *)(v1 + 40) = SessionId;
  *(_QWORD *)(v1 + 32) = (unsigned __int64)FastMutex & 0x7FFFFFFFFFFFFFFCi64;
LABEL_8:
  --CurrentThread->Tcb.AbAllocationRegionCount;
  KiAbThreadRemoveBoosts(&CurrentThread->Tcb, FastMutex, &a3);
  v7 = CurrentThread->Tcb.SpecialApcDisable++ == -1;
  if( v7
    && ($F25F8C4BA33AF922A5F1AF68CD89DDDF *)CurrentThread->Tcb.ApcState.ApcListHead[0].Flink != &CurrentThread->Tcb.152 )
  {
    KiCheckForKernelApcDelivery();
  }
  CurrentIrql = KeGetCurrentIrql();
  __writecr8(1ui64);
  if( !_interlockedbittestandreset(&FastMutex->Count, 0) )
    ExpAcquireFastMutexContended(FastMutex, (VOID *)v1);
  if( v1 )
    *(_BYTE *)(v1 + 26) |= 1u;
  FastMutex->Owner = KeGetCurrentThread();
  result = (VOID *)CurrentIrql;
  FastMutex->OldIrql = CurrentIrql;
  return result;
}

Referenced by: