and 32-bit registers. Some late-1980s Apple computers such as the Macintosh SE/30 and Macintosh IIx retained some 24-bit code in their ROMs despite being advertised as 32-bit computers. As a result, these computers require the installation of the MODE32 memory manager to address more than 8Mb of RAM.

The ARM1, supported 24-bit memory address, as it can access