qemu_irq isa_reserve_irq(int isairq) { if (isairq < 0 || isairq > 15) { hw_error("isa irq %d invalid", isairq); } if (isabus->assigned & (1 << isairq)) { hw_error("isa irq %d already assigned", isairq); } isabus->assigned |= (1 << isairq); return isabus->irqs[isairq]; }