IRQ_MASK
outb(imr_addr, IRQ_MASK(ICU_SLAVEID));
if ((isr & IRQ_MASK(7)) == 0)
#define IMEN_MASK(ai) (IRQ_MASK((ai)->at_irq))
outb(IO_ICU1 + ICU_IMR_OFFSET, IRQ_MASK(ICU_SLAVEID));