1/* $NetBSD: popcount64.c,v 1.7 2012/03/09 15:41:16 christos Exp $ */ 2/*- 3 * Copyright (c) 2009 The NetBSD Foundation, Inc. 4 * All rights reserved. 5 * 6 * This code is derived from software contributed to The NetBSD Foundation 7 * by Joerg Sonnenberger. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in 17 * the documentation and/or other materials provided with the 18 * distribution. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 23 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 24 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, 26 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 27 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 28 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 29 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 30 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34#include <sys/cdefs.h> 35__RCSID("$NetBSD: popcount64.c,v 1.7 2012/03/09 15:41:16 christos Exp $"); 36 37#if !defined(_KERNEL) && !defined(_STANDALONE) 38#include <limits.h> 39#include <stdint.h> 40#include <strings.h> 41#else 42#include <lib/libkern/libkern.h> 43#include <machine/limits.h> 44#endif 45 46#ifndef popcount64 // might be defined to use a __builtin 47 48/* 49 * If uint64_t is larger than size_t, the follow assumes that 50 * splitting into 32bit halves is faster. 51 * 52 * The native pocount64 version is based on the same ideas as popcount32(3), 53 * see popcount32.c for comments. 54 */ 55 56#if SIZE_MAX < 0xffffffffffffffffULL 57unsigned int 58popcount64(uint64_t v) 59{ 60 return popcount32((uint32_t)(v >> 32)) + 61 popcount32((uint32_t)(v & 0xffffffffULL)); 62} 63#else 64unsigned int 65popcount64(uint64_t v) 66{ 67 unsigned int c; 68 69 v = v - ((v >> 1) & (uint64_t)0x5555555555555555ULL); 70 v = (v & (uint64_t)0x3333333333333333ULL) + 71 ((v >> 2) & (uint64_t)0x3333333333333333ULL); 72 v = ((v + (v >> 4)) & (uint64_t)0x0f0f0f0f0f0f0f0fULL) * 73 (uint64_t)0x0101010101010101ULL; 74 c = (unsigned int)(v >> 56); 75 76 return c; 77} 78#endif 79 80#if ULONG_MAX == 0xffffffffffffffffULL 81__strong_alias(popcountl, popcount64) 82#endif 83 84#if ULLONG_MAX == 0xffffffffffffffffULL 85__strong_alias(popcountll, popcount64) 86#endif 87 88#endif /* !popcount64 */ 89