1 // Copyright 2015 The Go Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style
3 // license that can be found in the LICENSE file.
5 // +build amd64,!appengine,!gccgo
9 func popcnt(x word) int
10 func havePOPCNT() bool
12 var hasPOPCNT = havePOPCNT()
14 // popcount returns the population count (number of set bits) of x.
15 func popcount(x word) int {
19 return popcountTable(x) // faster than Hacker's Delight