XPost: alt.folklore.computers   
   From: terje.mathisen@tmsw.no   
      
   John Ames wrote:   
   > On Thu, 7 Aug 2025 02:22:05 -0000 (UTC)   
   > Lawrence D'Oliveiro  wrote:   
   >   
   >> That disparity between CPU and RAM speeds is even greater today than   
   >> it was back then. Yet we have moved away from adding ever-more-complex   
   >> instructions, and are getting better performance with simpler ones.   
   >>   
   >> How come? Caching.   
   >   
   > Yes, but complex instructions also make pipelining and out-of-order   
   > execution much more difficult - to the extent that, as far back as the   
   > Pentium Pro, Intel has had to implement the x86 instruction set as a   
   > microcoded program running on top of a simpler RISC architecture.   
   >   
   That's simply wrong:   
      
   The PPro had close to zero microcode actually running in any user program.   
      
   What it did have was decoders that would look at complex operations and   
   spit out two or more basic operations, like load+execute.   
      
   Later on we've seen the opposite where cmp+branch could be combined into   
   a single internal op.   
      
   Terje   
      
   --   
   -    
   "almost all programming can be viewed as an exercise in caching"   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)