PCI_CBBIOBASE
base = PCI_CBBIOBASE(read_config(fd, &p->pc_sel, basereg, 4));
limit = PCI_CBBIOBASE(read_config(fd, &p->pc_sel, limitreg, 4));
base = PCI_CBBIOBASE(val);
limit = PCI_CBBIOBASE(read_config(fd, &p->pc_sel, limitreg, 2));