Hitachi made the SuperH ISA, a RISC instruction set that was notable for being a 16 bit fixed ISA. It had extremely high code density, and was great in environm

Hitachi made the SuperH ISA, a RISC instruction set that was notable for being a 16 bit fixed ISA. It had extremely high code density, and was great in environments constrained by storage. They sold the technology to ARM. If you're familiar with Thumb, that's Hitachi patents at work. The Sega 32X, Saturn, and Dreamcast used SuperH CPUs. They even made a few supercomputers with SuperH CPUs, I believe the record for most digits of pi was once held by a Hitachi supercomputer. The linux kernel still support SuperH.