//摘自 helppc
                     PORTS  Common I/O Port Addresses

     Port addresses are not always constant across PC, AT and PS2
     Unless marked, port addresses are relative to PC and XT only

     000-00F  8237 DMA controller
     000 Channel 0 address register
     001 Channel 0 word count
     002 Channel 1 address register
     003 Channel 1 word count
     004 Channel 2 address register
     005 Channel 2 word count
     006 Channel 3 address register
     007 Channel 3 word count
     008 Status/command register
     009 Request register
     00A Mask register
     00B Mode register
     00C Clear MSB/LSB flip flop
     00D Master clear temp register
     00E Clear mask register
     00F Multiple mask register


      010-01F  8237 DMA Controller (PS2 model 60 & 80), reserved (AT)

      020-02F  8259A Master Programmable Interrupt Controller
      020 8259 Command port  (see 8259)
      021 8259 Interrupt mask register  (see 8259)

      030-03F  8259A Slave Programmable Interrupt Controller (AT,PS2)

      040-05F  8253 or 8254 Programmable Interval Timer (PIT, see 8253)
      040 8253 channel 0, counter divisor
      041 8253 channel 1, RAM refresh counter
      042 8253 channel 2, Cassette and speaker functions
      043 8253 mode control  (see 8253)
      044 8254 PS/2 extended timer
      047 8254 Channel 3 control byte

      060-067  8255 Programmable Peripheral Interface  (PC,XT, PCjr)
      060 8255 Port A keyboard input/output buffer (output PCjr)
      061 8255 Port B output
      062 8255 Port C input
      063 8255 Command/Mode control register


      060-06F  8042 Keyboard Controller  (AT,PS2)
      060 8042 Keyboard input/output buffer register
      061 8042 system control port (for compatability with 8255)
      064 8042 Keyboard command/status register

      070 CMOS RAM/RTC, also NMI enable/disable (AT,PS2, see RTC)
      071 CMOS RAM data  (AT,PS2)

      080 Manufacturer checkpoint port
      080-090  DMA Page Registers
      081 High order 4 bits of DMA channel 2 address
      082 High order 4 bits of DMA channel 3 address
      083 High order 4 bits of DMA channel 1 address

      090-097  POS/Programmable Option Select  (PS2)
      090 Central arbitration control Port
      091 Card selection feedback
      092 System control and status register
      094 System board enable/setup register
      095 Reserved
      096 Adapter enable/setup register

     097 Reserved

     0A0 NMI Mask Register (PC,XT) (write 80h to enable NMI, 00h disable)
     0A0-0BF  Second 8259 Programmable Interrupt Controller (AT, PS2)
     0A0 Second 8259 Command port  (see 8259)
     0A1 Second 8259 Interrupt mask register  (see 8259)

     0C0 TI SN76496 Programmable Tone/Noise Generator (PCjr)
     0C0-0DF  8237 DMA controller 2 (AT)
     0C2 DMA channel 3 selector  (see ports 6 & 82)

     0E0-0EF  Reserved

0F0-0FF  Math coprocessor (AT, PS2)
     0F0-0F5  PCjr Disk Controller
     0F0 Disk Controller
     0F2 Disk Controller control port
     0F4 Disk Controller status register
     0F5 Disk Controller data port

     0F8-0FF  Reserved for future microprocessor extensions

     100-10F  POS Programmable Option Select (PS2)
     100 POS Register 0, Adapter ID byte (LSB)
     101 POS Register 1, Adapter ID byte (MSB)
     102 POS Register 2, Option select data byte 1
         Bit 0 is card enable (CDEN)
     103 POS Register 3, Option select data byte 2
     104 POS Register 4, Option select data byte 3
     105 POS Register 5, Option select data byte 4
         Bit 7 is (-CHCK)
         Bit 6 is reserved
     106 POS Register 6, subaddress extension (LSB)
     107 POS Register 7, subaddress extension (MSB)

     110-1EF  System I/O channel

     170-17F  Fixed disk 1 (AT)
     170 disk 1 data
     171 disk 1 error
     172 disk 1 sector count
     173 disk 1 sector number
     174 disk 1 cylinder low
     175 disk 1 cylinder high

     176 disk 1 drive/head
     177 disk 1 status

     1F0-1FF  Fixed disk 0 (AT)
     1F0 disk 0 data
     1F1 disk 0 error
     1F2 disk 0 sector count
     1F3 disk 0 sector number
     1F4 disk 0 cylinder low
     1F5 disk 0 cylinder high
     1F6 disk 0 drive/head
     1F7 disk 0 status

     200-20F  Game Adapter (see GAME PORT or JOYSTICK)

     210-217  Expansion Card Ports (XT)
     210 Write: latch expansion bus data
         read:  verify expansion bus data
     211 Write: clear wait,test latch
         Read:  MSB of data address
     212 Read:  LSB of data address
     213 Write: 0=enable, 1=/disable expansion unit

      214-215  Receiver Card Ports
      214 write: latch data, read: data
      215 read:  MSB of address, next read: LSB of address

      21F Reserved

      220-26F  Reserved for I/O channel

      270-27F  Third parallel port (see PARALLEL PORT)
      278 data port
      279 status port
      27A control port

      280-2AF  Reserved for I/O channel

      2A2-2A3  MSM58321RS clock

      2B0-2DF  Alternate EGA, or 3270 PC video (XT, AT)

      2E0 Alternate EGA/VGA
      2E1 GPIB Adapter  (AT)

     2E2-2E3  Data acquisition adapter (AT)

     2E8-2EF  COM4 non PS2 UART (Reserved by IBM) (see UART)

     2F0-2F7  Reserved

     2F8-2FF  COM2 Second Asynchronous Adapter (see UART)
              Primary Asynchronous Adapter for PCjr

     300-31F  Prototype Experimentation Card (except PCjr)
              Periscope hardware debugger
     320-32F  Hard Disk Controller  (XT)
     320 Read from/Write to controller
     321 Read: Controller Status, Write: controller reset
     322 Write: generate controller select pulse
     323 Write: Pattern to DMA and interrupt mask register
         (see ports 0F,21,C2)
     324 disk attention/status

     330-33F  Reserved for XT/370

      340-35F  Reserved for I/O channel

      360-36F  PC Network

      370-377  Floppy disk controller (except PCjr)
      372 Diskette digital output
      374 Diskette controller status
      375 Diskette controller data
      376 Diskette controller data
      377 Diskette digital input

      378-37F  Second Parallel Printer (see PARALLEL PORT)
               First Parallel Printer (see PARALLEL PORT)
      378 data port
      379 status port
      37A control port

380-38F  Secondary Binary Synchronous Data Link Control (SDLC) adapter
      380 On board 8255 port A, internal/external sense
      381 On board 8255 port B, external modem interface
      382 On board 8255 port C, internal control and gating
      383 On board 8255 mode register

      384 On board 8253 channel square wave generator
      385 On board 8253 channel 1 inactivity time-out
      386 On board 8253 channel 2 inactivity time-out
      387 On board 8253 mode register
      388 On board 8273 read: status; Write: Command
      389 On board 8273 write: parameter; read: response
      38A On board 8273 transmit interrupt status
      38B On board 8273 receiver interrupt status
      38C On board 8273 data

      390-39F  Cluster Adapter

      3A0-3AF  Primary Binary Synchronous Data Link Control (SDLC) adapter
      3A0 On board 8255 port A, internal/external sense
      3A1 On board 8255 port B, external modem interface
      3A2 On board 8255 port C, internal control and gating
      3A3 On board 8255 mode register
      3A4 On board 8253 counter 0 unused
      3A5 On board 8253 counter 1 inactivity time-outs
      3A6 On board 8253 counter 2 inactivity time-outs
      3A7 On board 8253 mode register
      3A8 On board 8251 data

      3A9 On board 8251 command/mode/status register

      3B0-3BF Monochrome Display Adapter (write only, see 6845)
      3B0 port address decodes to 3B4
      3B1 port address decodes to 3B5
      3B2 port address decodes to 3B4
      3B3 port address decodes to 3B5
      3B4 6845 index register, selects which register [0-11h]
          is to be accessed through port 3B5
      3B5 6845 data register [0-11h] selected by port 3B4,
          registers 0C-0F may be read.  If a read occurs without
          the adapter installed, FFh is returned.  (see 6845)
      3B6 port address decodes to 3B4
      3B7 port address decodes to 3B5
      3B8 6845 Mode control register
      3B9 reserved for color select register on color adapter
      3BA status register (read only)
      3BB reserved for light pen strobe reset

      3BC-3BF  Primary Parallel Printer Adapter (see PARALLEL PORT)
      3BC parallel 1, data port
      3BD parallel 1, status port

     3BE parallel 1, control port

     3C0-3CF  EGA/VGA
     3C0 VGA attribute and sequencer register
     3C1 Other video attributes
     3C2 EGA, VGA, CGA input status 0
     3C3 Video subsystem enable
     3C4 CGA, EGA, VGA sequencer index
     3C5 CGA, EGA, VGA sequencer
     3C6 VGA video DAC PEL mask
     3C7 VGA video DAC state
     3C8 VGA video DAC PEL address
     3C9 VGA video DAC
     3CA VGA graphics 2 position
     3CC VGA graphics 1 position
     3CD VGA feature control
     3CE VGA graphics index
     3CF Other VGA graphics

     3D0-3DF Color Graphics Monitor Adapter (ports 3D0-3DB are
             write only, see 6845)
     3D0 port address decodes to 3D4
      3D1 port address decodes to 3D5
      3D2 port address decodes to 3D4
      3D3 port address decodes to 3D5
      3D4 6845 index register, selects which register [0-11h]
          is to be accessed through port 3D5
      3D5 6845 data register [0-11h] selected by port 3D4,
          registers 0C-0F may be read.  If a read occurs without
          the adapter installed, FFh is returned.  (see 6845)
      3D6 port address decodes to 3D4
      3D7 port address decodes to 3D5
      3D8 6845 Mode control register (CGA, EGA, VGA, except PCjr)
      3D9 color select palette register (CGA, EGA, VGA, see 6845)
      3DA status register (read only, see 6845, PCjr VGA access)
      3DB Clear light pen latch (any write)
      3DC Preset Light pen latch
      3DF CRT/CPU page register (PCjr only)

      3E8-3EF  COM3 non PS2 UART (Reserved by IBM) (see UART)

      3F0-3F7  Floppy disk controller (except PCjr)
      3F0 Diskette controller status A
      3F1 Diskette controller status B
      3F2 controller control port
      3F4 controller status register
      3F5 data register (write 1-9 byte command, see INT 13)
      3F6 Diskette controller data
      3F7 Diskette digital input

      3F8-3FF  COM1 Primary Asynchronous Adapter  (see UART)

      3220-3227  PS2 COM3 (see UART)
      3228-322F  PS2 COM4 (see UART)
      4220-4227  PS2 COM5 (see UART)
      4228-422F  PS2 COM6 (see UART)
      5220-5227  PS2 COM7 (see UART)
      5228-522F  PS2 COM8 (see UART)

      - many cards designed for the ISA BUS only uses the lower 10 bits
        of the port address but some ISA adapters use addresses beyond 3FF.
        Any address that matches in the lower 10 bits will decode to the
        same card.   It is up to the adapters to resolve or ignore the
        high bits of the port addresses.   An example would be the Cluster
        adapter that has a port address of 390h.  The second cluster
        adapter has a port address of 790h which resolves to the same port
     address with the cards determining which one actually gets the data.