The Reduced means that the instructions themselves are reduced, as in easier to implement and easier to implement in a pipelined implementation. As opposed to h

The Reduced means that the instructions themselves are reduced, as in easier to implement and easier to implement in a pipelined implementation. As opposed to having instructions with plenty of addressing modes, you have a lot of register-register instructions and load and store opcodes: You compute the addresses explicitly, using the register-register opcodes, then load from that address using a load opcode which doesn't do much ALU work, then work on the loaded value in the registers. Contrast this with a leading CISC design, the VAX, which had plenty of addressing modes which practically all opcodes could use. A single opcode could expand into a whole stream of micro-operations to compute the addresses being loaded from, actually perform the named opcode, and then compute the address being stored to, and possibly more. Doing that in the presence of virtual memory, where an opcode might have to be stopped and restarted so the OS could take a page fault, was rather nontrivial. https://link.springer.com/chapter/10.1007%2F0-387-27446-4_3 https://link.springer.com/chapter/10.1007%2F0-387-27446-4_3