From: anton@mips.complang.tuwien.ac.at   
      
   jgd@cix.co.uk (John Dallman) writes:   
   >] * "Trap and Emulate” is an illusion of compatibility"   
   >]   * Performance differential is too great for most applications   
      
   I disagree.  Trap-and-emulate may be too slow for a feature that you   
   want programmers to use in hot paths on current CPUs, but there are   
   other cases.  In particular, for a feature that cannot be implemented   
   properly yet, if you provide it as a trap-and-emulated instruction in   
   the current generation, and a faster implementation of the instruction   
   in a future implementation of the architecture, programmers will be   
   much less reluctant to use that instruction when its implementation is   
   fast on the dominant implementation of the day than if it just   
   produces a SIGILL or somesuch on older chips (or new, but   
   feature-reduced chips).  Intel's marketing does not understand that,   
   that's why they are selling feature-reduced versions of chips that   
   have AVX and AVX-512 in hardware.   
      
   - anton   
   --   
   'Anyone trying for "industrial quality" ISA should avoid undefined behavior.'   
     Mitch Alsup,    
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)