js jit is magic.js

/*
  Basic idea - measure cost of simplest operation of js in cpu cycles
  
  asm
  
  //var i = n;
  mov EAX, n
  
  // while(i--);
  a: dec EAX
  jnz a
  
  in native x86 asm it costs 2 cycles
*/

// cpuFreq - cpu frequency 

(function(n)
{
  var d = new Date, i = n;
  
  while(i--)
    ;
  
  return (new Date - d)/1e3/n;
})(1e8)*cpuFreq;

/*
  chrome7(v8)
  ~8
  
  opera 10.60(Carakan)
  ~14
  
  ie7(jscript5.7)
  ~168
  
  ff3.6(trace monkey)
  ~11
  
  ff4b3(Jaeger Monkey)
  ~8

  besen r120
  ~33
*/