Mercurial > hg > graal-compiler
comparison agent/src/share/classes/sun/jvm/hotspot/utilities/Bits.java @ 0:a61af66fc99e jdk7-b24
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author | duke |
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date | Sat, 01 Dec 2007 00:00:00 +0000 |
parents | |
children | c18cbe5936b8 |
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-1:000000000000 | 0:a61af66fc99e |
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1 /* | |
2 * Copyright 2001-2004 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, | |
20 * CA 95054 USA or visit www.sun.com if you need additional information or | |
21 * have any 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 | |
41 public static int setBits(int x, int m) { | |
42 return x | m; | |
43 } | |
44 | |
45 public static int clearBits(int x, int m) { | |
46 return x & ~m; | |
47 } | |
48 | |
49 public static int nthBit(int n) { | |
50 return (n > 32) ? 0 : (OneBit << n); | |
51 } | |
52 | |
53 public static int setNthBit(int x, int n) { | |
54 return setBits(x, nthBit(n)); | |
55 } | |
56 | |
57 public static int clearNthBit(int x, int n) { | |
58 return clearBits(x, nthBit(n)); | |
59 } | |
60 | |
61 public static boolean isSetNthBit(int word, int n) { | |
62 return maskBits(word, nthBit(n)) != NoBits; | |
63 } | |
64 | |
65 public static int rightNBits(int n) { | |
66 return (nthBit(n) - 1); | |
67 } | |
68 | |
69 public static int maskBits(int x, int m) { | |
70 return x & m; | |
71 } | |
72 | |
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) */ | |
79 public static int roundTo(int x, int s) { | |
80 int m = s - 1; | |
81 return maskBits(x + m, ~m); | |
82 } | |
83 } |