Run results for: math pow vs multiply (with few extra variants)

Run details:

User agent: Mozilla/5.0 (Linux; Android 10; K) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/144.0.0.0 Mobile Safari/537.36

Browser: Chrome Mobile 144

Operating system: Android

Device Platform: Mobile

Date tested: 6 months ago

pow

114.0M/s

mult

105.4M/s

pow (multiplication in for loop)

83.3M/s

pow2 bitwise

71.4M/s

pow2 multiplication

50.3M/s

pow2 summ

28.0M/s

View exact numbers

Test name	Executions per second
✓ pow	114,017,504 Ops/sec
mult	105,438,456 Ops/sec
pow (multiplication in for loop)	83,346,552 Ops/sec
pow2 bitwise	71,376,232 Ops/sec
pow2 multiplication	50,270,268 Ops/sec
pow2 summ	28,002,776 Ops/sec

Script Preparation code:

function powNaive(x, y) {
	if (!y) return 1;
	let tmp = x;
	for (let i = 1; i < y; i++) {
		tmp *= x;
  	}
	return tmp;
}

// from https://codereview.stackexchange.com/a/217369
function pow2B(x, y) {
    if (y < 2) { return y ? x : 1 }
    if (y & 1) { return x * pow2B(x, y & 0x7FFFFFFE)}
    const p = pow2B(x, y >> 1);
    return p * p;
}

// other two functions from the same stackexchange post
function pow(x, y) {
  if (!y) { return 1 }
  let tmp = res = x;
  for (let i = 1; i < y; i++) {
    for (let j = 1; j < x; j++) { tmp += res }
    res = tmp;
  }
  return res;
}

function pow2(x, y) {
  if (!y) { return 1; }
  if (y % 2) {
    return x * pow2(x, y - 1);
  }
  const p = pow2(x, y/2);
  return p * p;
}

Tests:

pow
var x = Math.pow(54,2);
mult
var y = 54*54
pow2 bitwise
var y = pow2B(54, 2)
pow2 summ
var y = pow(54, 2)
pow2 multiplication
var y = pow2(54, 2)
pow (multiplication in for loop)
var y = powNaive(54, 2)