From: notsaying@nospicedham.invalid.org   
      
   On Tue, 12 Mar 2019 16:23:43 GMT, Pabst Blue Ribbon    
   wrote:   
      
   > James Harris  wrote:   
   >> A small programming challenge if you are interested, just for fun.   
   >>   
   >> Say we want any value other than 0 in EAX to be reduced to 1 - e.g.   
   >> so that if non-zero means true but we want true to be 1.   
   >>   
   >> Is there a faster solution than the naive   
   >>   
   >>     cmp eax, 0   
   >>     je done   
   >>     mov eax, 1   
   >>   done:   
   >>   
   >> Naturally, the speed of that will depend on how predictable the input   
   >> values are. Taking into account the usual suspect characteristics of   
   >> x86 CPUs is there a generally faster solution?   
   >>   
   >> I can think of three bit-twiddling ways but I'm not sure they would   
   >> be faster than the above. In fact, I think they might be slower. In   
   >> any case I'd be interested to see what others think. I suspect some   
   >> of you may already have a preferred solution.   
   >>   
   >> So, any suggestions?   
   >   
   > ?   
   >   
   > and eax, 1   
   > done:   
   >   
   >   
   All even numbers map to zero! Ooops.   
      
      
      
   --   
   Bah, and indeed, Humbug.   
      
   --- SoupGate-Win32 v1.05   
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