Mercurial > hg > CbC > CbC_gcc
comparison gcc/config/vxlib.c @ 0:a06113de4d67
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author | kent <kent@cr.ie.u-ryukyu.ac.jp> |
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date | Fri, 17 Jul 2009 14:47:48 +0900 |
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children | 77e2b8dfacca |
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1 /* Copyright (C) 2002, 2003, 2004, 2005, 2009 Free Software Foundation, Inc. | |
2 Contributed by Zack Weinberg <zack@codesourcery.com> | |
3 | |
4 This file is part of GCC. | |
5 | |
6 GCC is free software; you can redistribute it and/or modify it under | |
7 the terms of the GNU General Public License as published by the Free | |
8 Software Foundation; either version 3, or (at your option) any later | |
9 version. | |
10 | |
11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY | |
12 WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
14 for more details. | |
15 | |
16 Under Section 7 of GPL version 3, you are granted additional | |
17 permissions described in the GCC Runtime Library Exception, version | |
18 3.1, as published by the Free Software Foundation. | |
19 | |
20 You should have received a copy of the GNU General Public License and | |
21 a copy of the GCC Runtime Library Exception along with this program; | |
22 see the files COPYING3 and COPYING.RUNTIME respectively. If not, see | |
23 <http://www.gnu.org/licenses/>. */ | |
24 | |
25 /* Threads compatibility routines for libgcc2 for VxWorks. | |
26 These are out-of-line routines called from gthr-vxworks.h. */ | |
27 | |
28 #include "tconfig.h" | |
29 #include "tsystem.h" | |
30 #include "gthr.h" | |
31 | |
32 #if defined(__GTHREADS) | |
33 #include <vxWorks.h> | |
34 #ifndef __RTP__ | |
35 #include <vxLib.h> | |
36 #endif | |
37 #include <taskLib.h> | |
38 #ifndef __RTP__ | |
39 #include <taskHookLib.h> | |
40 #else | |
41 # include <errno.h> | |
42 #endif | |
43 | |
44 /* Init-once operation. | |
45 | |
46 This would be a clone of the implementation from gthr-solaris.h, | |
47 except that we have a bootstrap problem - the whole point of this | |
48 exercise is to prevent double initialization, but if two threads | |
49 are racing with each other, once->mutex is liable to be initialized | |
50 by both. Then each thread will lock its own mutex, and proceed to | |
51 call the initialization routine. | |
52 | |
53 So instead we use a bare atomic primitive (vxTas()) to handle | |
54 mutual exclusion. Threads losing the race then busy-wait, calling | |
55 taskDelay() to yield the processor, until the initialization is | |
56 completed. Inefficient, but reliable. */ | |
57 | |
58 int | |
59 __gthread_once (__gthread_once_t *guard, void (*func)(void)) | |
60 { | |
61 if (guard->done) | |
62 return 0; | |
63 | |
64 #ifdef __RTP__ | |
65 __gthread_lock_library (); | |
66 #else | |
67 while (!vxTas ((void *)&guard->busy)) | |
68 taskDelay (1); | |
69 #endif | |
70 | |
71 /* Only one thread at a time gets here. Check ->done again, then | |
72 go ahead and call func() if no one has done it yet. */ | |
73 if (!guard->done) | |
74 { | |
75 func (); | |
76 guard->done = 1; | |
77 } | |
78 | |
79 #ifdef __RTP__ | |
80 __gthread_unlock_library (); | |
81 #else | |
82 guard->busy = 0; | |
83 #endif | |
84 return 0; | |
85 } | |
86 | |
87 #endif /* __GTHREADS */ |