fibo benchmark of InlineC vs compiled JS vs interpreted (for details see https://www.espruino.com/InlineC )

fibobench.js

// this runs native and fully in SRAM
// larger n will overflow 32bits, we don't care
var c = E.compiledC(`
// int fibo(int)
int fibo(int n){
 if(n <= 1){
  return n;
 }
 int fibo = 1;
 int fiboPrev = 1;
 for(int i = 2; i < n; ++i){
  int temp = fibo;
  fibo += fiboPrev;
  fiboPrev = temp;
 }
 return fibo;
}
`);

// native but lot of JS runtime in flash
function compjsfibo(n){
 "compiled";
 if(n <= 1){
  return n;
 }
 var fibo = 1;
 var fiboPrev = 1;
 for(var i = 2; i < n; ++i){
  var temp = fibo;
  fibo += fiboPrev;
  fiboPrev = temp;
 }
 return fibo;
}

//fully interpreted by JS runtime in flash
function jsfibo(n){
 if(n <= 1){
  return n;
 }
 var fibo = 1;
 var fiboPrev = 1;
 for(var i = 2; i < n; ++i){
  temp = fibo;
  fibo += fiboPrev;
  fiboPrev = temp;
 }
 return fibo;
}

function bench(n,func){
  var res=0,t=getTime();
  res=func(n);
  t=getTime()-t;
  print("time:",t*1000,"result=",res);
}
function benchall(n){
  [c.fibo,compjsfibo,jsfibo].forEach((f)=>bench(n,f));
}

benchall(200);

/*
STM32F103, 72Mhz

>benchall(200);
time: 0.40411949157 result= -552082539
time: 10.68615913391 result= 2.80571172992e+41
time: 130.16414642333 result= 2.80571172992e+41
>benchall(2000);
time: 0.70190429687 result= 1392522469
time: 103.10864448547 result= Infinity
time: 1273.37217330932 result= Infinity
=undefined
>benchall(20000);
time: 3.71646881103 result= 936372485
time: 1015.77520370483 result= Infinity
time: 12676.12385749816 result= Infinity


APM32F103, 96Mhz

>benchall(200);
time: 0.37789344787 result= -552082539
time: 10.35118103027 result= 2.80571172992e+41
time: 124.66263771057 result= 2.80571172992e+41
>benchall(2000);
time: 0.59556961059 result= 1392522469
time: 100.51822662353 result= Infinity
time: 1219.64669227600 result= Infinity
=undefined
>benchall(20000);
time: 2.85291671752 result= 936372485
time: 990.22006988525 result= Infinity
time: 12141.72148704528 result= Infinity


AIR32F103, 72Mhz

>benchall(200);
time: 0.46920776367 result= -552082539
time: 7.62367248535 result= 2.80571172992e+41
time: 101.34482383728 result= 2.80571172992e+41
>benchall(2000);
time: 0.76866149902 result= 1392522469
time: 71.71988487243 result= Infinity
time: 985.62550544738 result= Infinity
=undefined
>benchall(20000);
time: 3.77774238586 result= 936372485
time: 705.31296730041 result= Infinity
time: 9807.07502365112 result= Infinity


*/