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comparison src/thread/nds/SDL_sysmutex.c @ 2671:c3e7c0698cbb gsoc2008_nds

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some changes to the dummy driver for debug purposes that should be reverted. most importantly, commenting out a check for an env. var.
author Darren Alton <dalton@stevens.edu>
date Thu, 12 Jun 2008 02:38:49 +0000
parents 6e4669f4db49
children
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2670:6e4669f4db49 2671:c3e7c0698cbb
20 slouken@devolution.com 20 slouken@devolution.com
21 */ 21 */
22 22
23 #ifdef SAVE_RCSID 23 #ifdef SAVE_RCSID
24 static char rcsid = 24 static char rcsid =
25 "@(#) $Id: SDL_sysmutex.c,v 1.2 2001/04/26 16:50:18 hercules Exp $"; 25 "@(#) $Id: SDL_sysmutex.c,v 1.2 2001/04/26 16:50:18 hercules Exp $";
26 #endif 26 #endif
27 27
28 /* An implementation of mutexes using semaphores */ 28 /* An implementation of mutexes using semaphores */
29 29
30 #include <stdio.h> 30 #include <stdio.h>
33 #include "SDL_error.h" 33 #include "SDL_error.h"
34 #include "SDL_thread.h" 34 #include "SDL_thread.h"
35 #include "SDL_systhread_c.h" 35 #include "SDL_systhread_c.h"
36 36
37 37
38 struct SDL_mutex { 38 struct SDL_mutex
39 int recursive; 39 {
40 Uint32 owner; 40 int recursive;
41 SDL_sem *sem; 41 Uint32 owner;
42 SDL_sem *sem;
42 }; 43 };
43 44
44 /* Create a mutex */ 45 /* Create a mutex */
45 SDL_mutex *SDL_CreateMutex(void) 46 SDL_mutex *
47 SDL_CreateMutex(void)
46 { 48 {
47 SDL_mutex *mutex; 49 SDL_mutex *mutex;
48 50
49 /* Allocate mutex memory */ 51 /* Allocate mutex memory */
50 mutex = (SDL_mutex *)malloc(sizeof(*mutex)); 52 mutex = (SDL_mutex *) malloc(sizeof(*mutex));
51 if ( mutex ) { 53 if (mutex) {
52 /* Create the mutex semaphore, with initial value 1 */ 54 /* Create the mutex semaphore, with initial value 1 */
53 mutex->sem = SDL_CreateSemaphore(1); 55 mutex->sem = SDL_CreateSemaphore(1);
54 mutex->recursive = 0; 56 mutex->recursive = 0;
55 mutex->owner = 0; 57 mutex->owner = 0;
56 if ( ! mutex->sem ) { 58 if (!mutex->sem) {
57 free(mutex); 59 free(mutex);
58 mutex = NULL; 60 mutex = NULL;
59 } 61 }
60 } else { 62 } else {
61 SDL_OutOfMemory(); 63 SDL_OutOfMemory();
62 } 64 }
63 return mutex; 65 return mutex;
64 } 66 }
65 67
66 /* Free the mutex */ 68 /* Free the mutex */
67 void SDL_DestroyMutex(SDL_mutex *mutex) 69 void
70 SDL_DestroyMutex(SDL_mutex * mutex)
68 { 71 {
69 if ( mutex ) { 72 if (mutex) {
70 if ( mutex->sem ) { 73 if (mutex->sem) {
71 SDL_DestroySemaphore(mutex->sem); 74 SDL_DestroySemaphore(mutex->sem);
72 } 75 }
73 free(mutex); 76 free(mutex);
74 } 77 }
75 } 78 }
76 79
77 /* Lock the semaphore */ 80 /* Lock the semaphore */
78 int SDL_mutexP(SDL_mutex *mutex) 81 int
82 SDL_mutexP(SDL_mutex * mutex)
79 { 83 {
80 #ifdef DISABLE_THREADS 84 #ifdef DISABLE_THREADS
81 return 0; 85 return 0;
82 #else 86 #else
83 Uint32 this_thread; 87 Uint32 this_thread;
84 88
85 if ( mutex == NULL ) { 89 if (mutex == NULL) {
86 SDL_SetError("Passed a NULL mutex"); 90 SDL_SetError("Passed a NULL mutex");
87 return -1; 91 return -1;
88 } 92 }
89 93
90 this_thread = SDL_ThreadID(); 94 this_thread = SDL_ThreadID();
91 if ( mutex->owner == this_thread ) { 95 if (mutex->owner == this_thread) {
92 ++mutex->recursive; 96 ++mutex->recursive;
93 } else { 97 } else {
94 /* The order of operations is important. 98 /* The order of operations is important.
95 We set the locking thread id after we obtain the lock 99 We set the locking thread id after we obtain the lock
96 so unlocks from other threads will fail. 100 so unlocks from other threads will fail.
97 */ 101 */
98 SDL_SemWait(mutex->sem); 102 SDL_SemWait(mutex->sem);
99 mutex->owner = this_thread; 103 mutex->owner = this_thread;
100 mutex->recursive = 0; 104 mutex->recursive = 0;
101 } 105 }
102 106
103 return 0; 107 return 0;
104 #endif /* DISABLE_THREADS */ 108 #endif /* DISABLE_THREADS */
105 } 109 }
106 110
107 /* Unlock the mutex */ 111 /* Unlock the mutex */
108 int SDL_mutexV(SDL_mutex *mutex) 112 int
113 SDL_mutexV(SDL_mutex * mutex)
109 { 114 {
110 #ifdef DISABLE_THREADS 115 #ifdef DISABLE_THREADS
111 return 0; 116 return 0;
112 #else 117 #else
113 if ( mutex == NULL ) { 118 if (mutex == NULL) {
114 SDL_SetError("Passed a NULL mutex"); 119 SDL_SetError("Passed a NULL mutex");
115 return -1; 120 return -1;
116 } 121 }
117 122
118 /* If we don't own the mutex, we can't unlock it */ 123 /* If we don't own the mutex, we can't unlock it */
119 if ( SDL_ThreadID() != mutex->owner ) { 124 if (SDL_ThreadID() != mutex->owner) {
120 SDL_SetError("mutex not owned by this thread"); 125 SDL_SetError("mutex not owned by this thread");
121 return -1; 126 return -1;
122 } 127 }
123 128
124 if ( mutex->recursive ) { 129 if (mutex->recursive) {
125 --mutex->recursive; 130 --mutex->recursive;
126 } else { 131 } else {
127 /* The order of operations is important. 132 /* The order of operations is important.
128 First reset the owner so another thread doesn't lock 133 First reset the owner so another thread doesn't lock
129 the mutex and set the ownership before we reset it, 134 the mutex and set the ownership before we reset it,
130 then release the lock semaphore. 135 then release the lock semaphore.
131 */ 136 */
132 mutex->owner = 0; 137 mutex->owner = 0;
133 SDL_SemPost(mutex->sem); 138 SDL_SemPost(mutex->sem);
134 } 139 }
135 return 0; 140 return 0;
136 #endif /* DISABLE_THREADS */ 141 #endif /* DISABLE_THREADS */
137 } 142 }