if (VM.VerifyAssertions) VM.assert(index >= 0 && index < marks.length);
if (VM.VerifyAssertions) VM._assert(index >= 0 && index < marks.length);
  private int wordIndex (Object object) throws VM_PragmaUninterruptible {    int index = ((VM_Magic.objectAsAddress(object).diff(baseAddress)) / ALIGNMENT) / BITS_PER_INT;    if (VM.VerifyAssertions) VM.assert(index >= 0 && index < marks.length);    return index;  }