frezik , 2 months ago

No, that’s not what RISC is about. There was some early attempts to keep the number of instructions low–originally, ARM didn’t have a multiply instruction, and there’s still a bunch of microcontrollers you can buy that don’t have a divide instruction–but it was quickly abandoned as it’s just not that useful. It only holds back instructions that optimize common cases. Your compiler can implement multiplication by doing addition in a loop, but that’s not very efficient.

What really worked about it was keeping a separation between how memory is accessed. You don’t have an ADD instruction that can fetch from both registers or main memory. You have a MOV instruction that can fetch from memory into a register, and you have an ADD instruction that can work on registers.

ARM still does this just fine.