INT 15 - later PSIBM PS/2, any model/2s - RETURN DEVICE DESCRIPTOR TABLE (DDT) ENTRY BY I/O ADDRSS
	AX = D102h
	BX = entry number at which to start searching
	CX = requested I/O port address
	DX = 0000h (reserved, must be set to 0)
	ES:DI -> buffer to contain DDT entry (see #00535)
Return: AH = return code (see #00534)
	BX = DDT entry number where I/O port was found, or total entries
	     plus 1 if port was not found.
	CF set on error
	CF clear on success
	    ES:DI buffer filled with DDT entry
Desc:	the DDT is searched from the specified entry for the I/O port in CX,
	  and the first entry in which it is found is returned
SeeAlso: AH=C0h,AH=C7h,AH=C9h,AX=D100h,AX=D101h,AX=D103h,AX=D104h