APPENDIX C: Standard PC I/O Space Address Assignments

PC I/O Space Address Usage  ($ means hex address)

$0000 - $016F	Unavailable (Reserved, used on the Motherboard or Undefined)
$0170 - $0178	Second hard disk controller
$0179 - $01EF	Undefined
$01F0 - $01F8	First hard disk controller
$0200 - $0207	Game controller adapter
$0208 - $0237	Unavailable (Reserved or Undefined)
$0238 - $023B	Mouse port 1
$023C - $023F	Mouse port 0
$0240 - $0277	Unavailable (Reserved or Undefined)
$0278 - $027A	LPT3 printer port
$027B - $02E7	Not used
$02E8 - $02EF	COM4 serial port
$02F0 - $02F7	Not used
$02F8 - $02FF	COM2 serial port
$0300 - $036F	Not used
$0370 - $0377	Floppy drive controller 1
$0378 - $037A	LPT2 printer port
$037B - $03AF	Not used
$03B0 - $03BB	Monochrome video adapter/ VGA video
$03BC - $03BE	LPT1 printer port (usually on monochrome adapter) / VGA video
$03BF - $03CF	VGA video
$03D0 - $03DF	CGA video adapter/ VGA video
$03E0 - $03E7	Not used
$03E8 - $03EF	COM3 serial port
$03F0 - $03F7	Floppy drive controller 0
$03F8 - $03FF	COM1 serial port

VGA cards use the I/O addresses from $03B0 - $03DF if they can display
MDA/CGA/EGA graphics also.