Yeah, I'm not sure he takes into considered compressed instructions, which can be used anywhere, rather than being a separate mode like Thumb on ARM. Fusing in

Yeah, I'm not sure he takes into considered compressed instructions, which can be used anywhere, rather than being a separate mode like Thumb on ARM. Fusing instructions isn't just theoretical either. I'm pretty sure it is or will be a common optimisation for CPUs aiming for high performance. How exactly is two easily-fused 16-bit instructions worse than one 32-bit one? Is there really a practical difference other than the name of the instruction(s)? At the same time, the reduced transistor count you get from a simpler instruction set is not a benefit to be just dismissed either. I'm starting to see RISC-V cores being put all over the place in complex microcontrollers, because they're so damn cheap, yet have very decent performance. I know a guy developing a RISC-V core. He was involved with the proposal for a couple of instructions that would put the code density above Thumb for most code, and the performance of his core was better than Cortex-M0 at a similar or smaller gate count. I'm not sure if the instructions was added to the standard or not though. Even for high performance CPUs, there's a case to be made for requiring fewer transistors for the base implementation. It makes it easier to make low-power low-leakage cores for the heterogeneous architecture (big.little, M1, etc.) which is becoming so popular.