"Intel® APX demonstrates the advantage of the variable-length instruction encodings of x86 – new features enhancing the entire instruction set can be defined wi

"Intel® APX demonstrates the advantage of the variable-length instruction encodings of x86 – new features enhancing the entire instruction set can be defined with only incremental changes to the instruction-decode hardware." In other words, their initial sloppiness was a Feature™: our initial mess was so bad that changes like these don't make it any worse!