if (VM.VerifyAssertions) VM.assert(x >= 0 && x < (NONVOLATILE_MASK >>> NONVOLATILE_SHIFT));
if (VM.VerifyAssertions) VM._assert(x >= 0 && x < (NONVOLATILE_MASK >>> NONVOLATILE_SHIFT));
  final void setUnsignedNonVolatileOffset(int x) {    if (VM.VerifyAssertions) VM.assert(x >= 0 && x < (NONVOLATILE_MASK >>> NONVOLATILE_SHIFT));    _bits = (_bits & ~NONVOLATILE_MASK) | (((long)x) << NONVOLATILE_SHIFT);  }