RtlInitializeExtendedContext

NTSTATUS __stdcall RtlInitializeExtendedContext(VOID *Buffer, UINT64 ContextFlags, _CONTEXT_EX **ContextEx){
  int v3; 
  unsigned __int64 v5; 
  NTSTATUS result; 
  UINT64 v8; 

  v3 = ContextFlags;
  v5 = 0i64;
  LODWORD(v8) = 0;
  result = RtlpValidateContextFlags((unsigned int)ContextFlags, &v8);
  if( result >= 0 )
  {
    if( (v8 & 2) != 0 )
      v5 = KUSER_SHARED_DATA.XState.EnabledFeatures | KUSER_SHARED_DATA.XState.EnabledUserVisibleSupervisorFeatures;
    return RtlInitializeExtendedContext2((__int64)Buffer, v3, ContextEx, v5);
  }
  return result;
}

Referenced by:

KiRaiseException
KiUnwindUserSspForApcContextCopyBypass
PspDisassociateUmsThreadFromPrimary
PspGetContextThreadInternal
PspInitializeThunkContext
PspSetContextState
PspSetContextThreadInternal
PspWow64GetContextThread
PspWow64SetContextThread