/[jscoverage]/trunk/js/jslog2.cpp
ViewVC logotype

Contents of /trunk/js/jslog2.cpp

Parent Directory Parent Directory | Revision Log Revision Log


Revision 332 - (show annotations)
Thu Oct 23 19:03:33 2008 UTC (11 years, 7 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 /* -*- 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

  ViewVC Help
Powered by ViewVC 1.1.24