)
Values EMM386 I/O dispatch function is called with:
	CX = Ring0 code selector for I/O handler's segment
	DS = Ring0 data selector for I/O handler's segment (alias of CS)
	EDX = faulting I/O address
	ECX = direction (00000008h for byte output, 00000000h for byte input)
		(reportedly 00h for byte/word input, 04h for byte/word output
		  under DOS 6.22 EMM386)
	EAX = data in/out
Return: (via FAR RET)
	CF clear if I/O access successfully virtualized
	CF set if access not virtualized (default handler will be called to
	      perform the I/O)
BUG:	32-bit I/O on trapped ports hangs the DOS 6.22 EMM386
SeeAlso: #02815