Calculate population count (popcnt) on a 32-bit number, branch free

var popcnt32 = require('popcnt32')

popcnt32(0b1) // 1
popcnt32(0b1000001) // 2

Return number of 1-bits in int. Int is implicitly cast to a 32-bit unsigned int. This means popcnt32(-1) === 32 while popcnt32(1) === 1

npm install popcnt32

ISC