/[jscoverage]/trunk/js/jslog2.cpp
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Annotation of /trunk/js/jslog2.cpp

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Revision 332 - (hide annotations)
Thu Oct 23 19:03:33 2008 UTC (11 years, 5 months ago) by siliconforks
File size: 2899 byte(s)
Add SpiderMonkey from Firefox 3.1b1.

The following directories and files were removed:
correct/, correct.js
liveconnect/
nanojit/
t/
v8/
vprof/
xpconnect/
all JavaScript files (Y.js, call.js, if.js, math-partial-sums.js, md5.js, perfect.js, trace-test.js, trace.js)


1 siliconforks 332 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
2     /* ***** BEGIN LICENSE BLOCK *****
3     * Version: MPL 1.1/GPL 2.0/LGPL 2.1
4     *
5     * The contents of this file are subject to the Mozilla Public License Version
6     * 1.1 (the "License"); you may not use this file except in compliance with
7     * the License. You may obtain a copy of the License at
8     * http://www.mozilla.org/MPL/
9     *
10     * Software distributed under the License is distributed on an "AS IS" basis,
11     * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
12     * for the specific language governing rights and limitations under the
13     * License.
14     *
15     * The Original Code is Mozilla Communicator client code, released
16     * March 31, 1998.
17     *
18     * The Initial Developer of the Original Code is
19     * Netscape Communications Corporation.
20     * Portions created by the Initial Developer are Copyright (C) 1998
21     * the Initial Developer. All Rights Reserved.
22     *
23     * Contributor(s):
24     *
25     * Alternatively, the contents of this file may be used under the terms of
26     * either of the GNU General Public License Version 2 or later (the "GPL"),
27     * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
28     * in which case the provisions of the GPL or the LGPL are applicable instead
29     * of those above. If you wish to allow use of your version of this file only
30     * under the terms of either the GPL or the LGPL, and not to allow others to
31     * use your version of this file under the terms of the MPL, indicate your
32     * decision by deleting the provisions above and replace them with the notice
33     * and other provisions required by the GPL or the LGPL. If you do not delete
34     * the provisions above, a recipient may use your version of this file under
35     * the terms of any one of the MPL, the GPL or the LGPL.
36     *
37     * ***** END LICENSE BLOCK ***** */
38    
39     #include "jsstddef.h"
40     #include "jsbit.h"
41     #include "jsutil.h"
42    
43     /*
44     ** Compute the log of the least power of 2 greater than or equal to n
45     */
46     JS_PUBLIC_API(JSIntn) JS_CeilingLog2(JSUint32 n)
47     {
48     JSIntn log2;
49    
50     JS_CEILING_LOG2(log2, n);
51     return log2;
52     }
53    
54     /*
55     ** Compute the log of the greatest power of 2 less than or equal to n.
56     ** This really just finds the highest set bit in the word.
57     */
58     JS_PUBLIC_API(JSIntn) JS_FloorLog2(JSUint32 n)
59     {
60     JSIntn log2;
61    
62     JS_FLOOR_LOG2(log2, n);
63     return log2;
64     }
65    
66     /*
67     * js_FloorLog2wImpl has to be defined only for 64-bit non-GCC case.
68     */
69     #if !defined(JS_HAS_BUILTIN_BITSCAN64) && JS_BYTES_PER_WORD == 8
70    
71     JSUword
72     js_FloorLog2wImpl(JSUword n)
73     {
74     JSUword log2, m;
75    
76     JS_ASSERT(n != 0);
77    
78     log2 = 0;
79     m = n >> 32;
80     if (m != 0) { n = m; log2 = 32; }
81     m = n >> 16;
82     if (m != 0) { n = m; log2 |= 16; }
83     m = n >> 8;
84     if (m != 0) { n = m; log2 |= 8; }
85     m = n >> 4;
86     if (m != 0) { n = m; log2 |= 4; }
87     m = n >> 2;
88     if (m != 0) { n = m; log2 |= 2; }
89     log2 |= (n >> 1);
90    
91     return log2;
92     }
93    
94     #endif

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