Bitfields for OPTi 82C750 Vendetta (device 1) serial interrupt source:
Bit(s)	Description	)
 15-3	IRQ15-IRQ3 interrupt resource (0 = ISA, 1 = serial interrupt)
 2	SMI#, IOCHK#, PCIRQ3#-PCIRQ0# interrupt resource
	0 = ISA
	1 = serial interrupt
 1-0	IRQ1-IRQ0 interrupt resource (0 = ISA, 1 = serial interrupt)
SeeAlso: #00939,#00953