INT 1A - PCI BIOS v2.0c+ - READ CONFIGURATION WORD

	AX = B109h
	BH = bus number
	BL = device/function number (bits 7-3 device, bits 2-0 function)
	DI = register number (0000h-00FFh, must be multiple of 2) (see #00878)
Return: CF clear if successful
	    CX = word read
	CF set on error
	AH = status (00h,87h) (see #00729)
	EAX, EBX, ECX, and EDX may be modified
	all other flags (except IF) may be modified
Notes:	this function may require up to 1024 byte of stack; it will not enable
	  interrupts if they were disabled before making the call
	the meanings of BL and BH on entry were exchanged between the initial
	  drafts of the specification and final implementation
BUG:	the Award BIOS 4.51PG (dated 05/24/96) incorrectly returns FFFFh for
	  register 00h if the PCI function number is nonzero
SeeAlso: AX=B108h,AX=B10Ah,AX=B189h,INT 2F/AX=1684h/BX=304Ch