Bitfields for Intel 82371/82378/82379 SMI Request Register:
Bit(s)	Description	)
 15-9	reserved
 8	(82371SB only) Legacy USB SMI status
 7	APM SMI Status (write to PORT 00B2h triggered SMI)
 6	EXTSMI# SMI Status (EXTSMI# line triggered SMI)
 5	Fast-Off Timer expired
 4	IRQ12 triggered SMI
 3	IRQ8 triggered SMI
 2	IRQ4 triggered SMI
 1	IRQ3 triggered SMI
 0	IRQ1 triggered SMI
Note:	software must explicitly reset the appropriate bits
SeeAlso: #01064,#01081,#01167