1 | /* |
2 | * Copyright (C) 2003, 2006 Apple Computer, Inc. |
3 | * |
4 | * This library is free software; you can redistribute it and/or |
5 | * modify it under the terms of the GNU Lesser General Public |
6 | * License as published by the Free Software Foundation; either |
7 | * version 2 of the License, or (at your option) any later version. |
8 | * |
9 | * This library is distributed in the hope that it will be useful, |
10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
12 | * Lesser General Public License for more details. |
13 | * |
14 | * You should have received a copy of the GNU Lesser General Public |
15 | * License along with this library; if not, write to the Free Software |
16 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, |
17 | * USA. |
18 | * |
19 | */ |
20 | |
21 | #include <math.h> |
22 | #include "global.h" |
23 | |
24 | namespace KJS { |
25 | |
26 | // This file exists because JavaScriptCore needs to define the NaN and Inf globals in a way |
27 | // that does not use a static initializer so we don't have a framework initialization routine. |
28 | |
29 | // The trick is to define the NaN and Inf globals with a different type than the declaration. |
30 | // This trick works because the mangled name of the globals does not include the type, although |
31 | // I'm not sure that's guaranteed. There could be alignment issues with this, since arrays of |
32 | // characters don't necessarily need the same alignment doubles do, but for now it seems to work. |
33 | // It would be good to figure out a 100% clean way that still avoids code that runs at init time. |
34 | |
35 | #if (defined(AVOID_STATIC_CONSTRUCTORS) && !AVOID_STATIC_CONSTRUCTORS) |
36 | KJS_EXPORT extern const double NaN = NAN; |
37 | KJS_EXPORT extern const double Inf = INFINITY; |
38 | #elif PLATFORM(DARWIN) |
39 | |
40 | #if PLATFORM(BIG_ENDIAN) |
41 | KJS_EXPORT extern const unsigned char NaN[sizeof(double)] = { 0x7f, 0xf8, 0, 0, 0, 0, 0, 0 }; |
42 | KJS_EXPORT extern const unsigned char Inf[sizeof(double)] = { 0x7f, 0xf0, 0, 0, 0, 0, 0, 0 }; |
43 | #elif PLATFORM(MIDDLE_ENDIAN) |
44 | KJS_EXPORT extern const unsigned char NaN[] = { 0, 0, 0xf8, 0x7f, 0, 0, 0, 0 }; |
45 | KJS_EXPORT extern const unsigned char Inf[] = { 0, 0, 0xf0, 0x7f, 0, 0, 0, 0 }; |
46 | #else |
47 | KJS_EXPORT extern const unsigned char NaN[sizeof(double)] = { 0, 0, 0, 0, 0, 0, 0xf8, 0x7f }; |
48 | KJS_EXPORT extern const unsigned char Inf[sizeof(double)] = { 0, 0, 0, 0, 0, 0, 0xf0, 0x7f }; |
49 | #endif // PLATFORM(MIDDLE_ENDIAN) |
50 | |
51 | #else // !PLATFORM(DARWIN) |
52 | |
53 | // Note, we have to use union to ensure alignment. Otherwise, NaN_Bytes can start anywhere, |
54 | // while NaN_double has to be 4-byte aligned for 32-bits. |
55 | // With -fstrict-aliasing enabled, unions are the only safe way to do type masquerading. |
56 | |
57 | static const union { |
58 | struct { |
59 | unsigned char NaN_Bytes[8]; |
60 | unsigned char Inf_Bytes[8]; |
61 | } bytes; |
62 | |
63 | struct { |
64 | double NaN_Double; |
65 | double Inf_Double; |
66 | } doubles; |
67 | |
68 | } NaNInf = { { |
69 | #if PLATFORM(BIG_ENDIAN) |
70 | { 0x7f, 0xf8, 0, 0, 0, 0, 0, 0 }, |
71 | { 0x7f, 0xf0, 0, 0, 0, 0, 0, 0 } |
72 | #elif PLATFORM(MIDDLE_ENDIAN) |
73 | { 0, 0, 0xf8, 0x7f, 0, 0, 0, 0 }, |
74 | { 0, 0, 0xf0, 0x7f, 0, 0, 0, 0 } |
75 | #else |
76 | { 0, 0, 0, 0, 0, 0, 0xf8, 0x7f }, |
77 | { 0, 0, 0, 0, 0, 0, 0xf0, 0x7f } |
78 | #endif |
79 | } } ; |
80 | |
81 | KJS_EXPORT extern const double NaN = NaNInf.doubles.NaN_Double; |
82 | KJS_EXPORT extern const double Inf = NaNInf.doubles.Inf_Double; |
83 | |
84 | #endif // !PLATFORM(DARWIN) |
85 | |
86 | |
87 | } // namespace KJS |
88 | |