Register memory architecture
In computer engineering, a register–memory architecture is an instruction set architecture that allows operations to be performed on (or from) memory, as well as registers. If the architecture allows all operands to be in memory or in registers, or in combinations, it is called a "register plus memory" architecture.
In a register–memory approach one of the operands for ADD operation may be in memory, while the other is in a register. This differs from a load/store architecture (used by RISC designs such as MIPS) in which both operands for an ADD operation must be in registers before the ADD.