Format of PCI Configuration data for PC Technology RZ-1000 EIDE controller:
Offset	Size	Description	)
 00h 64 BYTEs	header (see #00878)
		(vendor ID 1042h, device ID 1000h)
 10h	DWORD	base address for controller I/O registers
		(set to 01F1h for primary controller, 0171h for secondary)
 14h	DWORD	base address for controller digital I/O port
		(set to 03F5h for primary, 0375h for secondary)
 40h	DWORD	???
		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	DWORD	???
 48h  8 BYTEs	???
 50h 176 BYTEs	unused???