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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.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// +build amd64,!appengine,!gccgo
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package intsets
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func popcnt(x word) int
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func havePOPCNT() bool
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var hasPOPCNT = havePOPCNT()
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// popcount returns the population count (number of set bits) of x.
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func popcount(x word) int {
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if hasPOPCNT {
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return popcnt(x)
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}
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return popcountTable(x) // faster than Hacker's Delight
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}
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