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+ - READ CONFIGURATION DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address. (PCIBM PC Technology devices)
	AX = B10Ah subfn 1042h
	BH = bus number
	BL = device/function number (bits 7-3 device, bits 2-0 function)
	DI = register number (0000h-00FFh) (see #00878)
Return: CF clear if successful
	    ECX = dword 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
SeeAlso: AX=B10Ah,AX=B10Ah/SF=1022h,AX=B10Ah/SF=1045h,AX=B10Ah/SF=8086h


Format of PCI Configuration data for PCIBM PC Technology RZ-1000 EIDE controller:
Offset	Size	Description	(Table 00928)
 00h 64 BYTEs	header (see #00878)
		(vendor ID 1042h, device ID 1000h)
 10h	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	base address for controller I/O registers
		(set to 01F1h for primary controller, 0171h for secondary)
 14h	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	base address for controller digital I/O port
		(set to 03F5h for primary, 0375h for secondary)
 40h	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	???
		bits 7-1: ???
		bit 13: read-ahead mode enabled
			(Read-Ahead is buggy on original RZ-1000, and is
			  thus typically disabled by clearing this bit)
		bit 16: ???
 44h	DWORDDoubleword; four bytes.	 Commonly used to hold a 32-bit segment:offset or selector:offset address.	???
 48h  8 BYTEs	???
 50h 176 BYTEs	unused???