3 * - By John Hodge (thePowersGang)
10 #include <threads_int.h>
12 #define SEMAPHORE_DEBUG 0 // Debug semaphores
16 // Initialise a semaphore
18 void Semaphore_Init(tSemaphore *Sem, int Value, int MaxValue, const char *Module, const char *Name)
20 memset(Sem, 0, sizeof(tSemaphore));
22 Sem->ModName = Module;
24 Sem->MaxValue = MaxValue;
27 // Wait for items to be avaliable
29 int Semaphore_Wait(tSemaphore *Sem, int MaxToTake)
34 Log_Warning("Threads", "Semaphore_Wait: User bug - MaxToTake(%i) < 0, Sem=%p(%s)",
35 MaxToTake, Sem, Sem->Name);
39 SHORTLOCK( &Sem->Protector );
41 // Check if there's already items avaliable
45 if( MaxToTake && Sem->Value > MaxToTake )
53 SHORTLOCK( &glThreadListLock );
55 // - Remove from active list
56 us = Threads_RemActive();
59 us->Status = THREAD_STAT_SEMAPHORESLEEP;
60 us->WaitPointer = Sem;
61 us->RetStatus = MaxToTake; // Use RetStatus as a temp variable
64 if(Sem->LastWaiting) {
65 Sem->LastWaiting->Next = us;
66 Sem->LastWaiting = us;
70 Sem->LastWaiting = us;
73 #if DEBUG_TRACE_STATE || SEMAPHORE_DEBUG
74 Log("%p (%i %s) waiting on semaphore %p %s:%s",
75 us, us->TID, us->ThreadName,
76 Sem, Sem->ModName, Sem->Name);
79 SHORTREL( &Sem->Protector ); // Release first to make sure it is released
80 SHORTREL( &glThreadListLock );
81 while( us->Status == THREAD_STAT_SEMAPHORESLEEP )
84 if(us->Status == THREAD_STAT_SEMAPHORESLEEP)
85 Log_Warning("Threads", "Semaphore %p %s:%s re-schedulued while asleep",
86 Sem, Sem->ModName, Sem->Name);
88 #if DEBUG_TRACE_STATE || SEMAPHORE_DEBUG
89 Log("Semaphore %p %s:%s woken", Sem, Sem->ModName, Sem->Name);
91 // We're only woken when there's something avaliable (or a signal arrives)
92 us->WaitPointer = NULL;
94 taken = us->RetStatus;
97 SHORTLOCK( &Sem->Protector );
100 // While there is space, and there are thread waiting
101 // wake the first thread and give it what it wants (or what's left)
102 while( (Sem->MaxValue == 0 || Sem->Value < Sem->MaxValue) && Sem->Signaling )
105 tThread *toWake = Sem->Signaling;
107 Sem->Signaling = Sem->Signaling->Next;
108 // Reset ->LastWaiting to NULL if we have just removed the last waiting thread
109 if( Sem->Signaling == NULL )
110 Sem->LastSignaling = NULL;
112 // Figure out how much to give
113 if( toWake->RetStatus && Sem->Value + toWake->RetStatus < Sem->MaxValue )
114 given = toWake->RetStatus;
116 given = Sem->MaxValue - Sem->Value;
120 #if DEBUG_TRACE_STATE || SEMAPHORE_DEBUG
121 Log("%p (%i %s) woken by wait on %p %s:%s",
122 toWake, toWake->TID, toWake->ThreadName,
123 Sem, Sem->ModName, Sem->Name);
126 // Save the number we gave to the thread's status
127 toWake->RetStatus = given;
130 SHORTLOCK( &glThreadListLock );
131 if( toWake->Status != THREAD_STAT_ACTIVE )
132 Threads_AddActive(toWake);
133 SHORTREL( &glThreadListLock );
135 SHORTREL( &Sem->Protector );
137 #if DEBUG_TRACE_STATE || SEMAPHORE_DEBUG
138 Log("Semaphore %p %s:%s took %i by wait",
139 Sem, Sem->ModName, Sem->Name, taken);
146 // Add items to a semaphore
148 int Semaphore_Signal(tSemaphore *Sem, int AmmountToAdd)
153 if( AmmountToAdd < 0 ) {
154 Log_Warning("Threads", "Semaphore_Signal: User bug - AmmountToAdd(%i) < 0, Sem=%p(%s)",
155 AmmountToAdd, Sem, Sem->Name);
157 SHORTLOCK( &Sem->Protector );
159 // Check if we have to block
160 if( Sem->MaxValue && Sem->Value == Sem->MaxValue )
164 Log_Debug("Threads", "Semaphore_Signal: IDLE Sem = %s:%s", Sem->ModName, Sem->Name);
165 Log_Debug("Threads", "Semaphore_Signal: Sem->Value(%i) == Sem->MaxValue(%i)", Sem->Value, Sem->MaxValue);
168 SHORTLOCK( &glThreadListLock );
169 // - Remove from active list
170 us = Threads_RemActive();
172 // - Mark as sleeping
173 us->Status = THREAD_STAT_SEMAPHORESLEEP;
174 us->WaitPointer = Sem;
175 us->RetStatus = AmmountToAdd; // Use RetStatus as a temp variable
178 if(Sem->LastSignaling) {
179 Sem->LastSignaling->Next = us;
180 Sem->LastSignaling = us;
184 Sem->LastSignaling = us;
187 #if DEBUG_TRACE_STATE || SEMAPHORE_DEBUG
188 Log("%p (%i %s) signaling semaphore %p %s:%s",
189 us, us->TID, us->ThreadName,
190 Sem, Sem->ModName, Sem->Name);
193 SHORTREL( &glThreadListLock );
194 SHORTREL( &Sem->Protector );
195 while(us->Status == THREAD_STAT_SEMAPHORESLEEP) Threads_Yield();
196 // We're only woken when there's something avaliable
197 us->WaitPointer = NULL;
199 added = us->RetStatus;
201 // Get the lock again
202 SHORTLOCK( &Sem->Protector );
207 // Figure out how much we need to take off
208 if( Sem->MaxValue && Sem->Value + AmmountToAdd > Sem->MaxValue)
209 added = Sem->MaxValue - Sem->Value;
211 added = AmmountToAdd;
215 // While there are items avaliable, and there are thread waiting
216 // wake the first thread and give it what it wants (or what's left)
217 while( Sem->Value && Sem->Waiting )
219 tThread *toWake = Sem->Waiting;
221 // Remove thread from list (double ended, so clear LastWaiting if needed)
222 Sem->Waiting = Sem->Waiting->Next;
223 if( Sem->Waiting == NULL )
224 Sem->LastWaiting = NULL;
226 // Figure out how much to give to woken thread
227 // - Requested count is stored in ->RetStatus
228 if( toWake->RetStatus && Sem->Value > toWake->RetStatus )
229 given = toWake->RetStatus;
234 // Save the number we gave to the thread's status
235 toWake->RetStatus = given;
237 if(toWake->bInstrTrace)
238 Log("%s(%i) given %i from %p", toWake->ThreadName, toWake->TID, given, Sem);
239 #if DEBUG_TRACE_STATE || SEMAPHORE_DEBUG
240 Log("%p (%i %s) woken by signal on %p %s:%s",
241 toWake, toWake->TID, toWake->ThreadName,
242 Sem, Sem->ModName, Sem->Name);
246 if( toWake->Status != THREAD_STAT_ACTIVE )
247 Threads_AddActive(toWake);
249 Warning("Thread %p (%i %s) is already awake", toWake, toWake->TID, toWake->ThreadName);
251 SHORTREL( &Sem->Protector );
257 // Get the current value of a semaphore
259 int Semaphore_GetValue(tSemaphore *Sem)
265 EXPORT(Semaphore_Init);
266 EXPORT(Semaphore_Wait);
267 EXPORT(Semaphore_Signal);