mirror of
https://github.com/golang/go
synced 2024-10-01 09:28:37 -06:00
3dedf801dd
Change-Id: I6f3b351d42f5534dd5a5ff161f1e5680b4dbfd58 Reviewed-on: https://go-review.googlesource.com/16793 Reviewed-by: Andrew Gerrand <adg@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org>
21 lines
483 B
Go
21 lines
483 B
Go
// Copyright 2015 The Go Authors. All rights reserved.
|
|
// Use of this source code is governed by a BSD-style
|
|
// license that can be found in the LICENSE file.
|
|
|
|
// +build amd64,!appengine,!gccgo
|
|
|
|
package intsets
|
|
|
|
func popcnt(x word) int
|
|
func havePOPCNT() bool
|
|
|
|
var hasPOPCNT = havePOPCNT()
|
|
|
|
// popcount returns the population count (number of set bits) of x.
|
|
func popcount(x word) int {
|
|
if hasPOPCNT {
|
|
return popcnt(x)
|
|
}
|
|
return popcountTable(x) // faster than Hacker's Delight
|
|
}
|