The Prime minicomputer architecture, from the 80's. Competed with Dec VAX, Data General Eclipse, etc.
The Prime architecture was based on the Multics design from a group of guys hailing from Honeywell and MIT. I worked on Primes for around 12 years, worked for Prime briefly in the 80's, and wrote an emulator that runs many versions of Prime's OS, Primos: https://github.com/prirun/p50em
Prime systems are very much the opposite of RISC, with instructions for:
- process exchange and task scheduling
- procedure call, incl arguments, ring crossing, stack handling, register saves
- decimal arithmetic, incl picture editing for COBOL & PL/I
- string instructions and picture editing
- 6 CPU modes for compatibility with older processors
- DMA, DMC, DMT, DMQ I/O modes for controller access to memory
- 32, 64, and 128-bit floating point