The reason CISC became so complicated was that microcode stores were getting larger. Once the decision is made to use microprogrammed control, the cost to ex

The reason CISC became so complicated was that microcode stores were getting larger. Once the decision is made to use microprogrammed control, the cost to expand an instruction set is very small; only a few more words of control store. Since the sizes of control memories are often powers of 2, sometimes the instruction set can be made more complex at no extra hardware cost by expanding the microprogram to completely fill the control memory. [1] The reason for an instruction like that Javascript one are similar: reports of Moore's Law demise are greatly exaggerated and DRAMs are getting bigger. Yes, these instructions may offend your sensibilities but the transistors are available and there are important benchmarks for important customers. Chips+ISAs aren't abelian groups, especially ARM chips+ISAs. RISC-V has extensions which promise to be the wild west all over again. [1] https://inst.eecs.berkeley.edu/~n252/paper/RISC-patterson.pdf https://inst.eecs.berkeley.edu/~n252/paper/RISC-patterson.pd...