Address Range           Description
-----------------       ------------------------------------------------
00 0000 - 03 FFFF       256K Chip RAM (A1000 Chip RAM,
                            1st 256K for A500/A2000)

04 0000 - 07 FFFF       256K bytes of Chip RAM (2nd 256K for A500/A2000)

08 0000 - 0F FFFF       512K  extended chip ram  (to 1 mb for a2000).

10 0000 - 1F FFFF       Reserved. Do not use.

20 0000 - 9F FFFF       Primary  8 mb auto-config space .

A0 0000 - BE FFFF       Reserved. Do not use.

BF D000 - BF DF00        8520-b  (access at even-byte addresses only)
    -         -
BF E001 - BF EF01        8520-a  (access at odd-byte addresses only)
    -         -
                        The underlined digit chooses which of the
                         16 internal registers  of the 8520 is to be
                        accessed.  See Appendix F.

C0 0000 - DF EFFF       Reserved.  Do not use.
   |
   | C0 0000 - D7 FFFF  Internal expansion (slow) memory (on some systems).
   |
   | D8 0000 - DB FFFF  Reserved.  Do not use.
   |
   | DC 0000 - DC FFFF  Real time clock (not accessable on all systems).
   |
   | DF F000 - DF FFFF  Chip registers.  See  appendix a  and  appendix b .
   +--

E0 0000 - E7 FFFF       Reserved.  Do not use.

E8 0000 - E8 FFFF        auto-config space .  boards appear here before
                        the system relocates them to their final address.

E9 0000 - EF FFFF       Secondary  auto-config space  (usually 64k i/o
                        boards).

F0 0000 - FB FFFF       Reserved.  Do not use.

FC 0000 - FF FFFF       256K System ROM.