protected static final int getSizeClass(VM_Address sp)
protected static final int getSizeClass(boolean isScalar, EXTENT bytes)
  protected static final int getSizeClass(VM_Address sp)    throws VM_PragmaInline {    if (VM.VerifyAssertions)      VM._assert(sp.toWord().EQ(sp.toWord().and(PAGE_MASK)));        sp = sp.add(SIZE_CLASS_WORD_OFFSET);    VM_Word wd = VM_Word.fromInt(VM_Magic.getMemoryWord(sp));    return wd.and(PAGE_MASK.not()).toInt();  }