I learned ARM assembly programming from Pete Cockerell's excellent book.
Today, ARM is known for low power consumption, but in the 1980s it's main selling point was its superior speed. At 4.5 MIPS (and up to a whopping 18 MIPS in laboratory conditions), it was running circles around the competition (Intel 80x86 & Motorola 680xx). The Archimedes had software emulation of the 80x86, which ran at IBM-PC/XT speed (in the IBM-PC/AT era). I used this emulator to run WordPerfect and the TopSpeed Modula-2 compiler in MS-DOS for programming assignments at university.
I still have the Acorn Prolog-X box sitting at a honorary place on my bookshelf above my current computer, just out of nostalgia.