js/src/t/bitops-nsieve-bits.js

   1 // The Great Computer Language Shootout
   2 //  http://shootout.alioth.debian.org
   3 //
   4 //  Contributed by Ian Osgood
   5
   6 function pad(n,width) {
   7   var s = n.toString();
   8   while (s.length < width) s = ' ' + s;
   9   return s;
  10 }
  11
  12 function primes(isPrime, n) {
  13   var i, count = 0, m = 10000<<n, size = m+31>>5;
  14
  15   for (i=0; i<size; i++) isPrime[i] = 0xffffffff;
  16
  17   for (i=2; i<m; i++)
  18     if (isPrime[i>>5] & 1<<(i&31)) {
  19       for (var j=i+i; j<m; j+=i)
  20         isPrime[j>>5] &= ~(1<<(j&31));
  21       count++;
  22     }
  23 }
  24
  25 function sieve() {
  26     for (var i = 4; i <= 4; i++) {
  27         var isPrime = new Array((10000<<i)+31>>5);
  28         primes(isPrime, i);
  29     }
  30 }
  31
  32 sieve();