Here you can find the source of pop_andnot(long A[], long B[], int wordOffset, int numWords)
public static long pop_andnot(long A[], long B[], int wordOffset, int numWords)
//package com.java2s; /**//from w w w .java2 s. c o m * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You under the Apache License, Version 2.0 * (the "License"); you may not use this file except in compliance with * the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ public class Main { /** Returns the popcount or cardinality of A & ~B * Neither array is modified. */ public static long pop_andnot(long A[], long B[], int wordOffset, int numWords) { // generated from pop_array via sed 's/A\[\([^]]*\)\]/\(A[\1] \& ~B[\1]\)/g' int n = wordOffset + numWords; long tot = 0, tot8 = 0; long ones = 0, twos = 0, fours = 0; int i; for (i = wordOffset; i <= n - 8; i += 8) { /*** C macro from Hacker's Delight #define CSA(h,l, a,b,c) \ {unsigned u = a ^ b; unsigned v = c; \ h = (a & b) | (u & v); l = u ^ v;} ***/ long twosA, twosB, foursA, foursB, eights; // CSA(twosA, ones, ones, (A[i] & ~B[i]), (A[i+1] & ~B[i+1])) { long b = (A[i] & ~B[i]), c = (A[i + 1] & ~B[i + 1]); long u = ones ^ b; twosA = (ones & b) | (u & c); ones = u ^ c; } // CSA(twosB, ones, ones, (A[i+2] & ~B[i+2]), (A[i+3] & ~B[i+3])) { long b = (A[i + 2] & ~B[i + 2]), c = (A[i + 3] & ~B[i + 3]); long u = ones ^ b; twosB = (ones & b) | (u & c); ones = u ^ c; } //CSA(foursA, twos, twos, twosA, twosB) { long u = twos ^ twosA; foursA = (twos & twosA) | (u & twosB); twos = u ^ twosB; } //CSA(twosA, ones, ones, (A[i+4] & ~B[i+4]), (A[i+5] & ~B[i+5])) { long b = (A[i + 4] & ~B[i + 4]), c = (A[i + 5] & ~B[i + 5]); long u = ones ^ b; twosA = (ones & b) | (u & c); ones = u ^ c; } // CSA(twosB, ones, ones, (A[i+6] & ~B[i+6]), (A[i+7] & ~B[i+7])) { long b = (A[i + 6] & ~B[i + 6]), c = (A[i + 7] & ~B[i + 7]); long u = ones ^ b; twosB = (ones & b) | (u & c); ones = u ^ c; } //CSA(foursB, twos, twos, twosA, twosB) { long u = twos ^ twosA; foursB = (twos & twosA) | (u & twosB); twos = u ^ twosB; } //CSA(eights, fours, fours, foursA, foursB) { long u = fours ^ foursA; eights = (fours & foursA) | (u & foursB); fours = u ^ foursB; } tot8 += pop(eights); } if (i <= n - 4) { long twosA, twosB, foursA, eights; { long b = (A[i] & ~B[i]), c = (A[i + 1] & ~B[i + 1]); long u = ones ^ b; twosA = (ones & b) | (u & c); ones = u ^ c; } { long b = (A[i + 2] & ~B[i + 2]), c = (A[i + 3] & ~B[i + 3]); long u = ones ^ b; twosB = (ones & b) | (u & c); ones = u ^ c; } { long u = twos ^ twosA; foursA = (twos & twosA) | (u & twosB); twos = u ^ twosB; } eights = fours & foursA; fours = fours ^ foursA; tot8 += pop(eights); i += 4; } if (i <= n - 2) { long b = (A[i] & ~B[i]), c = (A[i + 1] & ~B[i + 1]); long u = ones ^ b; long twosA = (ones & b) | (u & c); ones = u ^ c; long foursA = twos & twosA; twos = twos ^ twosA; long eights = fours & foursA; fours = fours ^ foursA; tot8 += pop(eights); i += 2; } if (i < n) { tot += pop((A[i] & ~B[i])); } tot += (pop(fours) << 2) + (pop(twos) << 1) + pop(ones) + (tot8 << 3); return tot; } /** Returns the number of bits set in the long */ public static int pop(long x) { /* Hacker's Delight 32 bit pop function: * http://www.hackersdelight.org/HDcode/newCode/pop_arrayHS.cc * int pop(unsigned x) { x = x - ((x >> 1) & 0x55555555); x = (x & 0x33333333) + ((x >> 2) & 0x33333333); x = (x + (x >> 4)) & 0x0F0F0F0F; x = x + (x >> 8); x = x + (x >> 16); return x & 0x0000003F; } ***/ // 64 bit java version of the C function from above x = x - ((x >>> 1) & 0x5555555555555555L); x = (x & 0x3333333333333333L) + ((x >>> 2) & 0x3333333333333333L); x = (x + (x >>> 4)) & 0x0F0F0F0F0F0F0F0FL; x = x + (x >>> 8); x = x + (x >>> 16); x = x + (x >>> 32); return ((int) x) & 0x7F; } }