VM._assert(false);
if (VM.VerifyAssertions) VM._assert(false);
  public VM_Address alloc(int pages) {    memoryResource.acquire(pages);    lock.acquire();    if (base.isZero()) {      base = vmResource.acquire(blocks, null);    }    int pageIndex = freeList.alloc(pages);    lock.release();    if (pageIndex == -1) {      VM.sysWriteln("RawPageAllocator: unable to satisfy raw page allocation request");      VM._assert(false);    }    return base.add(Conversions.pagesToBytes(pageIndex));  }