How to transform a binary integer into it's partial by shifting it all right of the "."

Question

Let's say we have a binary integer, which I'll call "A", like 101110101100100011. I want an efficient javascript function that makes the whole value partial (like the digits after a "."). So our function, which I'll call intToPart should return 0.101110101100100011 if we input "A".
My 1st idea is to do:

var A=191267 //our binary number in decimal. The computer will read it as "101110101100100011" when doing math.
function intToPart(myInt){
  var myNum=myInt.toString(2).length;
  return myInt/(1<<myNum);
}

Is their a much more efficient way of doing this, or is my way the best? My function returns the correct value, but I am not sure if there is some special way to bit shift it that is better.

What do you want to achieve with this? Are you trying to build your own floating point representation? — Bergi, Jul 25 '20 at 12:44

8HoLoN · Answer 1 · 2020-07-24T22:12:59.753

It should be more efficient because there's no call to toString.

var A = 191267 //our binary number in decimal. The computer will read it as "101110101100100011" when doing math.
function intToPart(myInt) {
    var myNum = 0, r = myInt;
    while (r!==0) { r >>= 1; myNum++ }
    return myInt / (1 << myNum);
}
console.log(intToPart(A))

or

var A = 191267 //our binary number in decimal. The computer will read it as "101110101100100011" when doing math.
function intToPart(myInt) {
    return myInt/(2**Math.ceil(Math.log2(myInt)));
}
console.log(intToPart(A))

How to transform a binary integer into it's partial by shifting it all right of the "."

1 Answers1