HT_MASK
pci_conf_write(pc, tag, off + PCI_HT_INTR_DATA, reg | HT_MASK);
pci_conf_write(pc, tag, sc->sc_off + PCI_HT_INTR_DATA, reg | HT_MASK);
reg &= ~(HT_ACTIVELOW | HT_EOI | HT_MASK);
pci_conf_write(pc, tag, sc->sc_off + PCI_HT_INTR_DATA, reg | HT_MASK);
value &= ~(HT_MASK | LT_MASK);