1 /* 2 * Copyright (c) 2001, 2004, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 package sun.jvm.hotspot.utilities; 26 27 /** Bit manipulation routines */ 28 29 public class Bits { 30 public static final int AllBits = ~0; 31 public static final int NoBits = 0; 32 public static final int OneBit = 1; 33 34 public static final int BitsPerByte = 8; 35 public static final int BitsPerInt = 32; 36 37 public static final int LogBytesPerInt = 2; 38 public static final int LogBytesPerLong = 3; 39 40 setBits(int x, int m)41 public static int setBits(int x, int m) { 42 return x | m; 43 } 44 clearBits(int x, int m)45 public static int clearBits(int x, int m) { 46 return x & ~m; 47 } 48 nthBit(int n)49 public static int nthBit(int n) { 50 return (n > 32) ? 0 : (OneBit << n); 51 } 52 setNthBit(int x, int n)53 public static int setNthBit(int x, int n) { 54 return setBits(x, nthBit(n)); 55 } 56 clearNthBit(int x, int n)57 public static int clearNthBit(int x, int n) { 58 return clearBits(x, nthBit(n)); 59 } 60 isSetNthBit(int word, int n)61 public static boolean isSetNthBit(int word, int n) { 62 return maskBits(word, nthBit(n)) != NoBits; 63 } 64 rightNBits(int n)65 public static int rightNBits(int n) { 66 return (nthBit(n) - 1); 67 } 68 maskBits(int x, int m)69 public static int maskBits(int x, int m) { 70 return x & m; 71 } 72 maskBitsLong(long x, long m)73 public static long maskBitsLong(long x, long m) { 74 return x & m; 75 } 76 77 /** Returns integer round-up to the nearest multiple of s (s must be 78 a power of two) */ roundTo(int x, int s)79 public static int roundTo(int x, int s) { 80 int m = s - 1; 81 return maskBits(x + m, ~m); 82 } 83 } 84