RBIL61 - Notes
[This file originally by Wim Osterholt <>,          
 though it has grown considerably since.]

		XTIBM PC XT, ATIBM PC AT and PS/2IBM PS/2, any model	 I/O port addresses

Do NOT consider this information to be complete and accurate.  If you want
to do hardware programming ALWAYS check the appropriate data sheets (but
even they are sometimes in error!).  Be aware that erroneous port programming
can put your data or even your hardware at risk.

There are a number of memory-mapped addresses in use for I/O; see MEMORY.LST
for details on memory-mapped I/O.


Note: the port description format is:

PPPPw RW  description

where:	PPPP	is the four-digit hex port number or a plus sign and three hex
		digits to indicate an offset from a base port address
	w	is blank for byte-size port, 'w' for word, and 'd' for dword
	R	is dash (or blank) if not readable, 'r' if sometimes readable,
		'R' if "always" readable, '?' if readability unknown
	W	is dash (or blank) if not writable, 'w' if sometimes writable,
		'W' if "always" writable, 'C' if write-clear, and
		'?' if writability unknown
                                                                                

Note:	Addresses above 03FF generally apply to EISA(Enhanced Industry-Standard Architecture) A 32-bit superset of the IBMInternational Busiuness Machines ATIBM PC AT's expansion bus (which is now known as the ISA or Industry-Standard Architecture bus). and PCI machines only !
	EISA(Enhanced Industry-Standard Architecture) A 32-bit superset of the IBMInternational Busiuness Machines ATIBM PC AT's expansion bus (which is now known as the ISA or Industry-Standard Architecture bus). port assignments:
	    1000-1FFF	slot 1 EISA(Enhanced Industry-Standard Architecture) A 32-bit superset of the IBMInternational Busiuness Machines ATIBM PC AT's expansion bus (which is now known as the ISA or Industry-Standard Architecture bus).
	    2000-2FFF	slot 2 EISA(Enhanced Industry-Standard Architecture) A 32-bit superset of the IBMInternational Busiuness Machines ATIBM PC AT's expansion bus (which is now known as the ISA or Industry-Standard Architecture bus).
	    3000-3FFF	slot 3 EISA(Enhanced Industry-Standard Architecture) A 32-bit superset of the IBMInternational Busiuness Machines ATIBM PC AT's expansion bus (which is now known as the ISA or Industry-Standard Architecture bus).
	    4000-4FFF	slot 4 EISA(Enhanced Industry-Standard Architecture) A 32-bit superset of the IBMInternational Busiuness Machines ATIBM PC AT's expansion bus (which is now known as the ISA or Industry-Standard Architecture bus).
	    5000-5FFF	slot 5 EISA(Enhanced Industry-Standard Architecture) A 32-bit superset of the IBMInternational Busiuness Machines ATIBM PC AT's expansion bus (which is now known as the ISA or Industry-Standard Architecture bus).
	    6000-6FFF	slot 6 EISA(Enhanced Industry-Standard Architecture) A 32-bit superset of the IBMInternational Busiuness Machines ATIBM PC AT's expansion bus (which is now known as the ISA or Industry-Standard Architecture bus).
	    7000-7FFF	slot 7 EISA(Enhanced Industry-Standard Architecture) A 32-bit superset of the IBMInternational Busiuness Machines ATIBM PC AT's expansion bus (which is now known as the ISA or Industry-Standard Architecture bus).