ROM Banks – Capitoline

The Amiga supports several ROM/Kickstart “banks”; The original A1000 bank is a 256k chunk starting at $FC0000, this was used right up until the first kickstart 1.4 (alpha), then there was a move to use 512k kickstarts starting earlier at $F80000 (an extra 256k)

The CDTV was an exception as it uses $F00000 for its extended ROM, these are separate physical ROMs (the CD32 also uses $200000 for the VCD/FMV/mpeg CD32 ROM).

This was pretty much the same until the CD32 which has a 1Mb kickstart, or, more correctly an original 512k kickstart at $F80000 and an extended kickstart at $E00000.

The A500+/A600/A1200/CD32 are all (electrically) capable of addressing a further 1Mb of space at $A80000 without any hardware modifications.

256k Kickstart
0xFC0000 - 0xFFFFFF 256k chunk

512k Kickstart
0xF80000 - 0xFFFFFF 512k chunk, overlaps the 256k chunk, but starts earlier

1Mb Kickstart
0xF80000 - 0xFFFFFF 512k chunk
0xE00000 - 0xE7FFFF 512k chunk

2Mb Kickstart
0xF80000 - 0xFFFFFF 512k chunk
0xE00000 - 0xE7FFFF 512k chunk
0xA80000 - 0xB7FFFF 1Mb chunk
Note, these banks are not contiguous.

ROMs can also be “softloaded” via relocation into different chunks of memory like 0xC00000/0x200000 via KickIt/ReKick/Degrader/RelocKick/skick/mkick etc. if you have some spare memory here’

The CD32 FMV ROM is a little bit of an anomaly, it’s technically an “expansion ROM”, which normally uses a different method for addressing, usually being mapped to a different address (therefore would normally be fully relocatable), however in the CD32, it always appears at a fixed $200000 address and apart from the initial autoconfig bootstrap, it uses normal kickstart style components (libraries) and it’s own ROM scanning – using a standard 0x4AFC MATCHWORD (which isn’t automatically relocatable), the libraries use lots of fixed addresses in the 0x200000-0x23FFFF range (256k ROM).

There are also other areas used for loading additional ROMs, expansion ROMs can appear at $E80000 (and maybe $E90000), but they get copied from there (there’s also the ZorroIII address $FF000000, but I’ll ignore 32bit addresses here for now).