private final void writeBarrier(VM_Address src, VM_Address tgt, VM_Address obj)
private final void writeBarrier(VM_Address src, VM_Address tgt)
  private final void writeBarrier(VM_Address src, VM_Address tgt, VM_Address obj)     throws VM_PragmaInline {    if (GATHER_WRITE_BARRIER_STATS) wbFastPathCounter++;    VM_Address old;    do {      old = VM_Address.fromInt(VM_Magic.prepare(src, 0));    } while (!VM_Magic.attempt(src, 0, old.toInt(), tgt.toInt()));    if (old.GE(RC_START))      decBuffer.pushOOL(old);    if (tgt.GE(RC_START))      incBuffer.pushOOL(tgt);    // VM_Magic.setMemoryAddress(src, tgt);  }