int forwarded = getForwardingWord(base); return VM_Address.fromInt(forwarded & ~GC_FORWARDING_MASK);
VM_Word forwarded = getForwardingWord(base); return forwarded.and(GC_FORWARDING_MASK.not()).toAddress();
  static VM_Address getForwardingPointer(VM_Address base) throws VM_PragmaUninterruptible, VM_PragmaInline {    int forwarded = getForwardingWord(base);    return VM_Address.fromInt(forwarded & ~GC_FORWARDING_MASK);  }