1. In a stored program computer an addressable storage containing data and instructions, said instructions including storage access instructions and register access instructions, instruction decode means connected to receive from said storage storage access and register access instructions and responsive to said storage access instructions for generating storage control signals and responsive to said register access instructions for generating register control signals, a plurality of addressable registers for storing data, a source of addresses, addressing means connected to receive addresses from said source of addresses and selectively operable under control of storage control signals to address said storage and under control of register control signals to address said registers, and means for applying said storage control signals and said register control signals to said addressing means whereby said storage is addressed upon said instruction decode means decoding a storage access instruction and said registers are addressed upon said instruction decode means decoding a register access instruction.