| /* |
| * Copyright (c) 2001, 2004, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| * |
| */ |
| |
| package sun.jvm.hotspot.utilities; |
| |
| /** Bit manipulation routines */ |
| |
| public class Bits { |
| public static final int AllBits = ~0; |
| public static final int NoBits = 0; |
| public static final int OneBit = 1; |
| |
| public static final int BitsPerByte = 8; |
| public static final int BitsPerInt = 32; |
| |
| public static final int LogBytesPerInt = 2; |
| public static final int LogBytesPerLong = 3; |
| |
| |
| public static int setBits(int x, int m) { |
| return x | m; |
| } |
| |
| public static int clearBits(int x, int m) { |
| return x & ~m; |
| } |
| |
| public static int nthBit(int n) { |
| return (n > 32) ? 0 : (OneBit << n); |
| } |
| |
| public static int setNthBit(int x, int n) { |
| return setBits(x, nthBit(n)); |
| } |
| |
| public static int clearNthBit(int x, int n) { |
| return clearBits(x, nthBit(n)); |
| } |
| |
| public static boolean isSetNthBit(int word, int n) { |
| return maskBits(word, nthBit(n)) != NoBits; |
| } |
| |
| public static int rightNBits(int n) { |
| return (nthBit(n) - 1); |
| } |
| |
| public static int maskBits(int x, int m) { |
| return x & m; |
| } |
| |
| public static long maskBitsLong(long x, long m) { |
| return x & m; |
| } |
| |
| /** Returns integer round-up to the nearest multiple of s (s must be |
| a power of two) */ |
| public static int roundTo(int x, int s) { |
| int m = s - 1; |
| return maskBits(x + m, ~m); |
| } |
| } |