src/vendor/leemon.js
function expand(x, n) {
  var ans=int2bigInt(0, (x.length>n ? x.length : n)*bpe, 0);
  copy_(ans, x);
  return ans;
}
function expand(x, n) {
  var ans=int2bigInt(0, (x.length>n ? x.length : n)*bpe, 0);
  copy_(ans, x);
  return ans;
}
function expand ( x , n ) { var ans = int2bigInt ( 0 , ( x . length > n ? x . length : n ) * bpe , 0 ) ; copy_ ( ans , x ) ; return ans ; }
return a copy of x with at least n elements, adding leading zeros if needed
return a copy of x with at least n elements adding leading zeros if needed