VM_Magic.setMemoryAddress( temp, 0 );
VM_Magic.setMemoryAddress(temp, VM_Address.zero());
  private static void freeBuffers(VM_Processor vp) throws VM_PragmaUninterruptible {    // remember address of last slot in first buffer (the next buffer pointer)    VM_Address temp = VM_Magic.objectAsAddress(vp.modifiedOldObjects).add(WRITE_BUFFER_SIZE - BYTES_IN_ADDRESS);    VM_Address buf = VM_Magic.getMemoryAddress( temp );    while( !buf.isZero() ) {      VM_Address nextbuf = VM_Magic.getMemoryAddress( buf.add(WRITE_BUFFER_SIZE - BYTES_IN_ADDRESS) );      VM_SysCall.call_I_A(VM_BootRecord.the_boot_record.sysFreeIP, buf);      buf = nextbuf;    }    // reset next pointer in first buffer to null    VM_Magic.setMemoryAddress( temp, 0 );  }