Reproduction micros

I would point out that RISC is not a goal in itself. Instead, the reason RISC is interesting is that -- at least at some point in the evolution of technology -- it was an architecture approach that results in more cost effective computers. That is, faster for the same money or less expensive for a given speed. It's easy to be led to the equivalence "register-memory instructions" == "complex instructions". If you're most familiar with Intel x86, or even saner architectures like VAX (which have memory to memory instructions, with a pile of addressing modes), that seems plausible. But, for example, the PDP-8 has register-memory instructions but it has a very simple instruction set and can be implemented in a tiny amount of logic. Similarly, register-memory instruction sets were used in many older architectures, and clearly were easy to do -- if your logic is tubes, you're not likely to implement large execution units! Even machines like the CDC 6000 peripheral processors, which have a pile of extra logic for controlling the CPU and surprising features like a barrel shifter, take only a few thousand gates. paul