ICU_OFFSET
outb(IO_ICU1+1, ICU_OFFSET); /* starting at this vector index */
outb(IO_ICU2+1, ICU_OFFSET+8); /* staring at this vector index */
icu[1] = ICU_OFFSET; /* starting at this vector index */
icu[1] = ICU_OFFSET + 8; /* starting at this vector index */
outb(IO_ICU1+1, ICU_OFFSET); /* int base: not used */
outb(IO_ICU2+1, ICU_OFFSET+8); /* int base + offset for master: not used */
outb(IO_ICU1 + PIC_ICW2, ICU_OFFSET);
outb(IO_ICU2 + PIC_ICW2, ICU_OFFSET + 8);
idt_vec_reserve(iv, ICU_OFFSET + i);
idt_vec_set(iv, ICU_OFFSET + i, legacy_stubs[i].ist_entry);
idtvec = ICU_OFFSET + pin;