Amiga memory map

From Amiga Coding
Jump to: navigation, search

Standard amount of memory in the Amiga

Model Chip RAM Fast RAM Kickstart ROM
Amiga 1000 256KB None 256KB
Amiga 500 512KB None 256KB
Amiga 500+ 1MB None 512KB
Amiga 2000 512KB, later 1MB None 256KB
Amiga 3000 1-2MB 1MB 512KB
Amiga 600 1MB None 512KB
Amiga 1200 2MB None 512KB
Amiga 4000 2MB 2-4MB 512KB

Memory map

Note: Models that are based on the same map are not listed, e.g. CDTV is based on A500 architecture, and the A1500 & A2500 are variations on the A2000. Where differences exist they are specified in brackets.

Address Range Size Category Function
A1000 A500 / 2000 A500+ A600 A1200 A3000 A4000
000000-03FFFF 256KB Chip RAM First 256KB of chip RAM
040000-07FFFF 256KB 256KB chip RAM expansion card Second 256KB of chip RAM (to 512KB)
080000-0FFFFF 512KB Reserved 512KB chip RAM expansion card (A500 trapdoor) Second 512KB of chip RAM (to 1MB)
100000-1FFFFF 1MB Reserved 1MB chip RAM expansion card Second 1MB of chip RAM (to 2MB)
200000-5FFFFF 4MB Zorro-II space First 4 MB Auto-config space / Fast RAM
600000-9FFFFF 4MB Second 4 MB Auto-config space / Fast RAM PCMCIA memory card / Fast RAM Second 4 MB Auto-config space / Fast RAM
A00000-A7FFFF 512KB Reserved Reserved PCMCIA control registers Reserved
A80000-BEFFFF 1472KB Reserved
BF0000-BFFFFF 64KB CIAs 8520 CIAs and timers
C00000-C7FFFF 512KB Slow-fast RAM Reserved Pseudo-fast RAM Reserved Chip register shadow
C80000-CFFFFF 512KB Reserved for pseudo-fast RAM
D00000-D7FFFF 512KB Reserved
D80000-D8FFFF 64KB Reserved Reserved Reserved (Selected by SPARE_CS) Clock Port (Selected by SPARE_CS) Reserved
D90000-D9FFFF 64KB Reserved Reserved (Selected by NET_CS) Reserved
DA0000-DBFFFF 128KB Reserved IDE controller Reserved
DC0000-DCFFFF 64KB Real Time Clock Real time clock (RTC)
DD0000-DD0FFF 4KB Reserved Reserved SCSI controller SCSI controller
DD1000-DD3FFF 12KB IDE controller
DD4000-DDFFFF 48KB Reserved
DE0000-DEFFFF 64KB Mainboard resources
DF0000-DFFFFF 64KB Custom chip registers
E00000-E7FFFF 512KB Reserved Reserved for first 512KB of 1MB system ROM Reserved
E80000-E8FFFF 64KB Auto-config space. Boards appear here before the system relocates them to their final address.
E90000-EFFFFF 448KB Secondary auto-config space (usually 64K I/O boards)
F00000-F7FFFF 512KB Extended ROM Reserved Extended ROM (CDTV) Reserved Flash ROM / Extended ROM (CD32) Diagnostic ROM
F80000-FBFFFF 256KB Kickstart ROM Reserved System ROM
FC0000-FFFFFF 256KB System ROM
32-bit Addresses
01000000 - 03FFFFFF 48MB Reserved N/A Reserved
04000000-06FFFFFF 48MB Fast RAM Reserved for motherboard RAM expansion
07000000-07FFFFFF 16MB Motherboard RAM
08000000-0FFFFFFF 128MB CPU slot expansion
10000000-7FFFFFFF 1792MB Zorro-III space Zorro-III expansion space
80000000-FEFFFFFF 2032MB Reserved Reserved
FF000000-FF00FFFF 64KB Zorro-III config space
FF010000-FFFFFFFF 16320KB Reserved

Note that various modifications and third party hardware can change the details of this map, particularly those expansions that add additional addressing capabilities, e.g. 32-bit accelerators in A1200s, 2MB chip RAM modifications in A500s etc.

Some special addresses:
* 000000-000100 - MC680x0 Exception Vector Assignment table  (if VBR=0)
* 000004        - Exec base (pointer to exec.library jumptable) 

Sources for this info

  • Amiga Hardware Reference Manual (1986)
  • M68000 Programmer's Reference Manual (1984,fourth edition)
  • (for standard amount of memory)
Personal tools