INT 1A - PCI BIOS(Basic Input/Output System) A set of standardized calls giving low-level access to the hardware.  The BIOS is the lowest software layer above the actual hardware and serves to insulate programs (and operating systems) which use it from the details of accessing the hardware directly. v2.0c+ - WRITE CONFIGURATION DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address. (32-bit)
	AX = B18Dh
	BH = bus number
	BL = device/function number (bits 7-3 device, bits 2-0 function)
	DI = register number (multiple of 4 less than 0100h)
	ECX = dword to write
Return: as for AX=B10Dh
Note:	the meanings of BL and BH on return were exchanged between the initial
	  drafts of the specification and final implementation
SeeAlso: AX=B10Dh,AX=B18Bh,AX=B18Ch