RISC instruction sets I have known and disliked
CISC has always been much nicer to hard write assembly code in than RISC is.  The only reason RISC was able to take off was that most code started to be generated by compilers rather than through assemblers.<p>Given the advance of modern computer architecture that the author talks about many of the old advantages of RISC no longer apply.  If you&#x27;re going to be doing out of order execution the the extra effort in implementing some extra instructions really isn&#x27;t important for application processors.<p>The big advantage that RISC has these days is that fixed width instructions are easy on the decoder.  You can also have variable width instruction that use UTF8esque byte marking to make things easier on the decoder but x86 doesn&#x27;t have anything like that.  But then again separating them entirely in the ISA makes thing easier on the designers.<p>Oh, and it&#x27;s a bad idea to touch memory multiple times in a single instruction on a modern machine but Intel&#x27;s optimization manuals warn you not to do that and compilers abide by those warnings.  If you want an ISA feature that&#x27;s really hard to design into a high performance uArch then there&#x27;s indirect addressing but unlike most CISC ISAs x86 managed to avoid that one.<p>The advantages of RISC might be overblown in some sense, but there have been a lot of new instruction set architectures developed over the last 20 years when the RISC&#x2F;CISC debates were raging.  Many of those have been weird in various ways but almost all look a lot more like RISC instruction sets than CISC instruction sets and it&#x27;s not just because people are following the herd.<p>And I&#x27;ve got the sense that my inside view of the issue is underestimating now advantageous RISCishness is.  When ARM had the opportunity to redesign their ISA when the transitioned to 64 bits they simplified their ISA quite a bit and increased the number of registers from 16 to 32, basically making their ISA much more similar to a classical RISC design.  I don&#x27;t really understand why they thought that going that way was an advantage but it seems like people actually involved with designing these things instead of just thinking about them in their armchairs still think that RISC has a lot of advantages.