The SH microprocessor: 16-bit fixed length instruction set provides better power and die size

As RISC architectures enter the embedded computing realm, a better compromise between performance, price, and power must be reached. Existing RISC microprocessors are not designed for embedded applications. The Hitachi SH microprocessor is an example of a new breed of RISC CPUs designed strictly for embedded applications. The defining feature of the SH which separates it from other RISC CPUs is its fixed 16-bit instruction length. The author discusses the advantages of this type of architecture and establishes a rationale for its superiority for embedded applications. The concept of microprocessor efficiency is introduced and used to determine value.<>