Devices are required to comply with a protocol so which the interrupt-request (IRQ) lines might be shared. The PCI bus includes 4 interrupt lines, INTA# by INTD#, all of which are offered to each device. Around eight PCI gadgets share the exact same IRQ line (INTINA# by way of INTINH#) https://nathanlabsadvisory.com/smart-contract-audit-copyright-companies-1/