Memory.zeroSmall(cell, VM_Extent.fromInt(cellSize[sizeClass]));
Memory.zeroSmall(cell, VM_Extent.fromIntZeroExtend(cellSize[sizeClass]));
  protected final void free(VM_Address cell, VM_Address block, int sizeClass)    throws VM_PragmaInline {    Memory.zeroSmall(cell, VM_Extent.fromInt(cellSize[sizeClass]));    addToFreeList(cell, block);    if (maintainInUse() && (decInUse(block) == 0))      freeBlock(block, sizeClass);  }