Fixing commenting (always nice)
[tpg/acess2.git] / Kernel / threads.c
index f726f27..99a9add 100644 (file)
@@ -7,28 +7,30 @@
 #include <threads.h>
 #include <errno.h>
 
+#define DEBUG_TRACE_TICKETS    0
+
 // === CONSTANTS ===
 #define        DEFAULT_QUANTUM 10
 #define        DEFAULT_TICKETS 5
 #define MAX_TICKETS            10
 const enum eConfigTypes        cCONFIG_TYPES[] = {
-       CFGT_HEAPSTR,   // CFG_VFS_CWD
-       CFGT_INT,       // CFG_VFS_MAXFILES
+       CFGT_HEAPSTR,   // e.g. CFG_VFS_CWD
+       CFGT_INT,       // e.g. CFG_VFS_MAXFILES
        CFGT_NULL
 };
 
 // === IMPORTS ===
-extern void    ArchThreads_Init();
-extern void    Proc_Start();
-extern tThread *Proc_GetCurThread();
+extern void    ArchThreads_Init(void);
+extern void    Proc_Start(void);
+extern tThread *Proc_GetCurThread(void);
 extern int     Proc_Clone(Uint *Err, Uint Flags);
 extern void    Proc_CallFaultHandler(tThread *Thread);
 
 // === PROTOTYPES ===
-void   Threads_Init();
+void   Threads_Init(void);
  int   Threads_SetName(char *NewName);
 char   *Threads_GetName(int ID);
-void   Threads_SetTickets(int Num);
+void   Threads_SetTickets(tThread *Thread, int Num);
 tThread        *Threads_CloneTCB(Uint *Err, Uint Flags);
  int   Threads_WaitTID(int TID, int *status);
 tThread        *Threads_GetThread(Uint TID);
@@ -36,46 +38,38 @@ void        Threads_AddToDelete(tThread *Thread);
 tThread        *Threads_int_GetPrev(tThread **List, tThread *Thread);
 void   Threads_Exit(int TID, int Status);
 void   Threads_Kill(tThread *Thread, int Status);
-void   Threads_Yield();
-void   Threads_Sleep();
-void   Threads_Wake(tThread *Thread);
+void   Threads_Yield(void);
+void   Threads_Sleep(void);
+ int   Threads_Wake(tThread *Thread);
 void   Threads_AddActive(tThread *Thread);
- int   Threads_GetPID();
- int   Threads_GetTID();
-tUID   Threads_GetUID();
+ int   Threads_GetPID(void);
+ int   Threads_GetTID(void);
+tUID   Threads_GetUID(void);
  int   Threads_SetUID(Uint *Errno, tUID ID);
-tGID   Threads_GetGID();
+tGID   Threads_GetGID(void);
  int   Threads_SetGID(Uint *Errno, tUID ID);
-void   Threads_Dump();
+void   Threads_Dump(void);
+void   Mutex_Acquire(tMutex *Mutex);
+void   Mutex_Release(tMutex *Mutex);
+ int   Mutex_IsLocked(tMutex *Mutex);
 
 // === GLOBALS ===
 // -- Core Thread --
+// Only used for the core kernel
 tThread        gThreadZero = {
-       NULL, 0,        // Next, Lock
-       THREAD_STAT_ACTIVE,     // Status
-       0,      // Exit Status
-       0, 0,   // TID, TGID
-       0, 0,   // UID, GID
-       0,      // Parent Thread ID
-       "ThreadZero",   // Name
-       
-       0,      // Kernel Stack
-       {0},    // Saved State
-       {0},    // VM State
-       
-       0, 0,   // Current Fault, Fault Handler
-       
-       NULL, NULL,     // Messages, Last Message
-       DEFAULT_QUANTUM, DEFAULT_QUANTUM,       // Quantum, Remaining
-       DEFAULT_TICKETS,
-       {0}     // Default config to zero
+       Status: THREAD_STAT_ACTIVE,     // Status
+       ThreadName:     "ThreadZero",   // Name
+       Quantum: DEFAULT_QUANTUM,       // Default Quantum
+       Remaining:      DEFAULT_QUANTUM,        // Current Quantum
+       NumTickets:     DEFAULT_TICKETS // Number of tickets
        };
 // -- Processes --
 // --- Locks ---
-volatile int   giThreadListLock = 0;   ///\note NEVER use a heap function while locked
+tShortSpinlock glThreadListLock;       ///\note NEVER use a heap function while locked
 // --- Current State ---
 volatile int   giNumActiveThreads = 0;
-volatile int   giTotalTickets = 0;
+//volatile int giTotalTickets = 0;
+volatile int   giFreeTickets = 0;
 volatile Uint  giNextTID = 1;
 // --- Thread Lists ---
 tThread        *gActiveThreads = NULL;         // Currently Running Threads
@@ -85,33 +79,18 @@ tThread     *gDeleteThreads = NULL;         // Threads to delete
 
 // === CODE ===
 /**
- * \fn void Threads_Init()
+ * \fn void Threads_Init(void)
  * \brief Initialse the thread list
  */
-void Threads_Init()
+void Threads_Init(void)
 {
        ArchThreads_Init();
        
        // Create Initial Task
        gActiveThreads = &gThreadZero;
-       giTotalTickets = gThreadZero.NumTickets;
+       //giFreeTickets = gThreadZero.NumTickets;
        giNumActiveThreads = 1;
-       
-       #if 1
-       // Create Idle Task
-       if(Proc_Clone(0, 0) == 0)
-       {
-               tThread *cur = Proc_GetCurThread();
-               cur->ThreadName = "Idle Thread";
-               Threads_SetTickets(0);  // Never called randomly
-               cur->Quantum = 1;       // 1 slice quantum
-               HALT();
-               for(;;) {
-                       HALT(); // Just yeilds
-               }
-       }
-       #endif
-       
+               
        Proc_Start();
 }
 
@@ -122,10 +101,13 @@ void Threads_Init()
 int Threads_SetName(char *NewName)
 {
        tThread *cur = Proc_GetCurThread();
-       if( IsHeap(cur->ThreadName) )
-               free( cur->ThreadName );
-       cur->ThreadName = malloc(strlen(NewName)+1);
-       strcpy(cur->ThreadName, NewName);
+       char    *oldname = cur->ThreadName;
+       
+       cur->ThreadName = NULL;
+       
+       if( IsHeap(oldname) )   free( oldname );
+       
+       cur->ThreadName = strdup(NewName);
        return 0;
 }
 
@@ -138,25 +120,29 @@ char *Threads_GetName(int ID)
        if(ID == -1) {
                return Proc_GetCurThread()->ThreadName;
        }
+       // TODO: Find a thread and get its name
        return NULL;
 }
 
 /**
- * \fn void Threads_SetTickets(int Num)
+ * \fn void Threads_SetTickets(tThread *Thread, int Num)
  * \brief Sets the 'priority' of a task
  */
-void Threads_SetTickets(int Num)
+void Threads_SetTickets(tThread *Thread, int Num)
 {
-       tThread *cur = Proc_GetCurThread();
+       if(Thread == NULL)
+               Thread = Proc_GetCurThread();
        if(Num < 0)     return;
        if(Num > MAX_TICKETS)   Num = MAX_TICKETS;
        
-       LOCK( &giThreadListLock );
-       giTotalTickets -= cur->NumTickets;
-       cur->NumTickets = Num;
-       giTotalTickets += Num;
-       //LOG("giTotalTickets = %i", giTotalTickets);
-       RELEASE( &giThreadListLock );
+       if( Thread != Proc_GetCurThread() ) {
+               SHORTLOCK( &glThreadListLock );
+               giFreeTickets -= Thread->NumTickets - Num;
+               Thread->NumTickets = Num;
+               SHORTREL( &glThreadListLock );
+       }
+       else
+               Thread->NumTickets = Num;
 }
 
 /**
@@ -173,9 +159,11 @@ tThread *Threads_CloneTCB(Uint *Err, Uint Flags)
                *Err = -ENOMEM;
                return NULL;
        }
+       memcpy(new, cur, sizeof(tThread));
        
+       new->CurCPU = -1;
        new->Next = NULL;
-       new->IsLocked = 0;
+       memset( &new->IsLocked, 0, sizeof(new->IsLocked));
        new->Status = THREAD_STAT_ACTIVE;
        new->RetStatus = 0;
        
@@ -184,8 +172,7 @@ tThread *Threads_CloneTCB(Uint *Err, Uint Flags)
        new->PTID = cur->TID;
        
        // Clone Name
-       new->ThreadName = malloc(strlen(cur->ThreadName)+1);
-       strcpy(new->ThreadName, cur->ThreadName);
+       new->ThreadName = strdup(cur->ThreadName);
        
        // Set Thread Group ID (PID)
        if(Flags & CLONE_VM)
@@ -266,10 +253,11 @@ int Threads_WaitTID(int TID, int *status)
                 int    initStatus = t->Status;
                 int    ret;
                
-               if(initStatus != THREAD_STAT_ZOMBIE)
+               if(initStatus != THREAD_STAT_ZOMBIE) {
                        while(t->Status == initStatus) {
                                Threads_Yield();
                        }
+               }
                
                ret = t->RetStatus;
                switch(t->Status)
@@ -292,6 +280,7 @@ int Threads_WaitTID(int TID, int *status)
 /**
  * \fn tThread *Threads_GetThread(Uint TID)
  * \brief Gets a thread given its TID
+ * \param TID  Thread ID
  */
 tThread *Threads_GetThread(Uint TID)
 {
@@ -367,7 +356,9 @@ void Threads_Exit(int TID, int Status)
                Threads_Kill( Proc_GetCurThread(), (Uint)Status & 0xFF );
        else
                Threads_Kill( Threads_GetThread(TID), (Uint)Status & 0xFF );
-       for(;;) HALT(); // Just in case
+       // Halt forever, just in case
+       for(;;)
+               HALT();
 }
 
 /**
@@ -395,18 +386,20 @@ void Threads_Kill(tThread *Thread, int Status)
        }
        #endif
        
-       ///\note Double lock is needed due to overlap of locks
+       ///\note Double lock is needed due to overlap of lock areas
        
        // Lock thread (stop us recieving messages)
-       LOCK( &Thread->IsLocked );
+       SHORTLOCK( &Thread->IsLocked );
        
        // Lock thread list
-       LOCK( &giThreadListLock );
+       SHORTLOCK( &glThreadListLock );
        
        // Get previous thread on list
        prev = Threads_int_GetPrev( &gActiveThreads, Thread );
        if(!prev) {
                Warning("Proc_Exit - Current thread is not on the active queue");
+               Thread->IsLocked.Lock = 0;      // We can't use SHORTREL as that starts IRQs again
+               SHORTREL( &glThreadListLock );
                return;
        }
        
@@ -423,7 +416,9 @@ void Threads_Kill(tThread *Thread, int Status)
        prev->Next = Thread->Next;      // Remove from active
        
        giNumActiveThreads --;
-       giTotalTickets -= Thread->NumTickets;
+       if( Thread != Proc_GetCurThread() )
+               giFreeTickets -= Thread->NumTickets;
+       //Log("Threads_Kill: giFreeTickets = %i", giFreeTickets);
        
        // Mark thread as a zombie
        Thread->RetStatus = Status;
@@ -438,8 +433,8 @@ void Threads_Kill(tThread *Thread, int Status)
        }
        
        // Release spinlocks
-       RELEASE( &Thread->IsLocked );   // Released first so that it IS released
-       RELEASE( &giThreadListLock );
+       Thread->IsLocked.Lock = 0;      // Released first so that it IS released
+       SHORTREL( &glThreadListLock );
        
        //Log("Thread %i went *hurk*", Thread->TID);
        
@@ -447,20 +442,20 @@ void Threads_Kill(tThread *Thread, int Status)
 }
 
 /**
- * \fn void Threads_Yield()
+ * \fn void Threads_Yield(void)
  * \brief Yield remainder of timeslice
  */
-void Threads_Yield()
+void Threads_Yield(void)
 {
        Proc_GetCurThread()->Remaining = 0;
        HALT();
 }
 
 /**
- * \fn void Threads_Sleep()
+ * \fn void Threads_Sleep(void)
  * \brief Take the current process off the run queue
  */
-void Threads_Sleep()
+void Threads_Sleep(void)
 {
        tThread *cur = Proc_GetCurThread();
        tThread *thread;
@@ -468,19 +463,20 @@ void Threads_Sleep()
        //Log_Log("Threads", "%i going to sleep", cur->TID);
        
        // Acquire Spinlock
-       LOCK( &giThreadListLock );
+       SHORTLOCK( &glThreadListLock );
        
        // Get thread before current thread
        thread = Threads_int_GetPrev( &gActiveThreads, cur );
        if(!thread) {
                Warning("Threads_Sleep - Current thread is not on the active queue");
                Threads_Dump();
+               SHORTREL( &glThreadListLock );
                return;
        }
        
        // Don't sleep if there is a message waiting
        if( cur->Messages ) {
-               RELEASE( &giThreadListLock );
+               SHORTREL( &glThreadListLock );
                return;
        }
        
@@ -496,55 +492,77 @@ void Threads_Sleep()
        
        // Reduce the active count & ticket count
        giNumActiveThreads --;
-       giTotalTickets -= cur->NumTickets;
+       // - No need to alter giFreeTickets (we're being executed)
        
        // Mark thread as sleeping
        cur->Status = THREAD_STAT_SLEEPING;
        
        // Release Spinlock
-       RELEASE( &giThreadListLock );
+       SHORTREL( &glThreadListLock );
        
        while(cur->Status != THREAD_STAT_ACTIVE)        HALT();
 }
 
 
 /**
- * \fn void Threads_Wake( tThread *Thread )
+ * \fn int Threads_Wake( tThread *Thread )
  * \brief Wakes a sleeping/waiting thread up
+ * \param Thread       Thread to wake
+ * \return Boolean Failure (Returns ERRNO)
  */
-void Threads_Wake(tThread *Thread)
+int Threads_Wake(tThread *Thread)
 {
        tThread *prev;
+       
+       if(!Thread)
+               return -EINVAL;
+       
        switch(Thread->Status)
        {
-       case THREAD_STAT_ACTIVE:        break;
-       case THREAD_STAT_SLEEPING:
-               //Log_Log("Threads", "Waking %i (%p) from sleeping", Thread->TID, Thread);
-               LOCK( &giThreadListLock );
+       case THREAD_STAT_ACTIVE:
+               Log("Thread_Wake: Waking awake thread (%i)", Thread->TID);
+               return -EALREADY;
+       case THREAD_STAT_SLEEPING:      // TODO: Comment better
+               //Log_Log("Threads", "Waking %i (%p) from sleeping (CPU=%i)",
+               //      Thread->TID, Thread, Thread->CurCPU);
+               SHORTLOCK( &glThreadListLock );
                prev = Threads_int_GetPrev(&gSleepingThreads, Thread);
                prev->Next = Thread->Next;      // Remove from sleeping queue
                Thread->Next = gActiveThreads;  // Add to active queue
                gActiveThreads = Thread;
                giNumActiveThreads ++;
-               giTotalTickets += Thread->NumTickets;
+               // Thread can't be the current, so no need to check
+               Thread->CurCPU = -1;
+               giFreeTickets += Thread->NumTickets;
+               #if DEBUG_TRACE_TICKETS
+               Log("Threads_Wake: giFreeTickets = %i", giFreeTickets);
+               #endif
                Thread->Status = THREAD_STAT_ACTIVE;
-               RELEASE( &giThreadListLock );
-               break;
+               SHORTREL( &glThreadListLock );
+               return -EOK;
        case THREAD_STAT_WAITING:
                Warning("Thread_Wake - Waiting threads are not currently supported");
-               break;
+               return -ENOTIMPL;
        case THREAD_STAT_DEAD:
                Warning("Thread_Wake - Attempt to wake dead thread (%i)", Thread->TID);
-               break;
+               return -ENOTIMPL;
        default:
                Warning("Thread_Wake - Unknown process status (%i)\n", Thread->Status);
-               break;
+               return -EINTERNAL;
        }
 }
 
-void Threads_WakeTID(tTID Thread)
+/**
+ * \brief Wake a thread given the TID
+ * \param TID  Thread ID to wake
+ * \return Boolean Faulure (errno)
+ */
+int Threads_WakeTID(tTID TID)
 {
-       Threads_Wake( Threads_GetThread(Thread) );
+       tThread *thread = Threads_GetThread(TID);
+       if(!thread)
+               return -ENOENT;
+       return Threads_Wake( thread );
 }
 
 /**
@@ -553,18 +571,20 @@ void Threads_WakeTID(tTID Thread)
  */
 void Threads_AddActive(tThread *Thread)
 {
-       LOCK( &giThreadListLock );
+       SHORTLOCK( &glThreadListLock );
        Thread->Next = gActiveThreads;
        gActiveThreads = Thread;
        giNumActiveThreads ++;
-       giTotalTickets += Thread->NumTickets;
-       //Log("Threads_AddActive: giNumActiveThreads = %i, giTotalTickets = %i",
-       //      giNumActiveThreads, giTotalTickets);
-       RELEASE( &giThreadListLock );
+       // Thread can't be the current, so no need to check
+       giFreeTickets += Thread->NumTickets;
+       #if DEBUG_TRACE_TICKETS
+       Log("Threads_AddActive: giFreeTickets = %i", giFreeTickets);
+       #endif
+       SHORTREL( &glThreadListLock );
 }
 
 /**
- * \fn void Threads_SetSignalHandler(Uint Handler)
+ * \fn void Threads_SetFaultHandler(Uint Handler)
  * \brief Sets the signal handler for a signal
  */
 void Threads_SetFaultHandler(Uint Handler)
@@ -605,23 +625,25 @@ void Threads_Fault(int Num)
                HALT();
        }
        
+       thread->CurFaultNum = Num;
+       
        Proc_CallFaultHandler(thread);
 }
 
 // --- Process Structure Access Functions ---
-tPID Threads_GetPID()
+tPID Threads_GetPID(void)
 {
        return Proc_GetCurThread()->TGID;
 }
-tTID Threads_GetTID()
+tTID Threads_GetTID(void)
 {
        return Proc_GetCurThread()->TID;
 }
-tUID Threads_GetUID()
+tUID Threads_GetUID(void)
 {
        return Proc_GetCurThread()->UID;
 }
-tGID Threads_GetGID()
+tGID Threads_GetGID(void)
 {
        return Proc_GetCurThread()->GID;
 }
@@ -651,28 +673,25 @@ int Threads_SetGID(Uint *Errno, tGID ID)
 }
 
 /**
- * \fn void Threads_Dump()
+ * \fn void Threads_Dump(void)
  * \brief Dums a list of currently running threads
  */
-void Threads_Dump()
+void Threads_Dump(void)
 {
        tThread *thread;
-       tThread *cur = Proc_GetCurThread();
        
        Log("Active Threads:");
        for(thread=gActiveThreads;thread;thread=thread->Next)
        {
-               Log("%c%i (%i) - %s",
-                       (thread==cur?'*':' '),
-                       thread->TID, thread->TGID, thread->ThreadName);
+               Log(" %i (%i) - %s (CPU %i)",
+                       thread->TID, thread->TGID, thread->ThreadName, thread->CurCPU);
                Log("  %i Tickets, Quantum %i", thread->NumTickets, thread->Quantum);
                Log("  KStack 0x%x", thread->KernelStack);
        }
        Log("Sleeping Threads:");
        for(thread=gSleepingThreads;thread;thread=thread->Next)
        {
-               Log("%c%i (%i) - %s",
-                       (thread==cur?'*':' '),
+               Log(" %i (%i) - %s",
                        thread->TID, thread->TGID, thread->ThreadName);
                Log("  %i Tickets, Quantum %i", thread->NumTickets, thread->Quantum);
                Log("  KStack 0x%x", thread->KernelStack);
@@ -680,53 +699,131 @@ void Threads_Dump()
 }
 
 /**
- * \fn tThread *Threads_GetNextToRun(int CPU)
+ * \fn tThread *Threads_GetNextToRun(int CPU, tThread *Last)
  * \brief Gets the next thread to run
+ * \param CPU  Current CPU
+ * \param Last The thread the CPU was running
  */
-tThread *Threads_GetNextToRun(int CPU)
+tThread *Threads_GetNextToRun(int CPU, tThread *Last)
 {
        tThread *thread;
         int    ticket;
         int    number;
        
+       // TODO: Enable the code to tell if the current CPU has the lock or
+       //       another does.
+       
+       // Check if the thread list is locked by other code
+       // - If so, don't switch (give it a chance to complete)
+       if( IS_LOCKED(&glThreadListLock) )
+               return Last;
+       
+       // Clear Delete Queue
+       while(gDeleteThreads)
+       {
+               thread = gDeleteThreads->Next;
+               if( IS_LOCKED(&gDeleteThreads->IsLocked) ) {    // Only free if structure is unused
+                       gDeleteThreads->Status = THREAD_STAT_NULL;
+                       free( gDeleteThreads );
+               }
+               gDeleteThreads = thread;
+       }
+       
+       // No active threads, just take a nap
        if(giNumActiveThreads == 0) {
-               //Log_Debug("Threads", "CPU%i has no threads to run", CPU);
+               #if DEBUG_TRACE_TICKETS
+               Log("No active threads");
+               #endif
                return NULL;
        }
        
+       // Lock thread list
+       // - HLT lock (Used because only another CPU can obtain the lock,
+       //   but it has a potentially long lock period)
+       // - Well, this CPU can obtain the lock, but that is aliveviated by
+       //   the above.
+       SHORTLOCK( &glThreadListLock );
+       
        // Special case: 1 thread
        if(giNumActiveThreads == 1) {
-               //Log_Debug("Threads", "CPU%i has only one thread %i %s",
-               //      CPU, gActiveThreads->TID, gActiveThreads->ThreadName);
-               return gActiveThreads;
+               if( gActiveThreads->CurCPU == -1 )
+                       gActiveThreads->CurCPU = CPU;
+               SHORTREL( &glThreadListLock );
+               if( gActiveThreads->CurCPU == CPU )
+                       return gActiveThreads;
+               return NULL;    // CPU has nothing to do
        }
        
-       //Log(" Threads_GetNextToRun: giNumActiveThreads=%i,giTotalTickets=%i",
-       //      giNumActiveThreads, giTotalTickets);
-       // Get the ticket number
-       ticket = number = rand() % giTotalTickets;
+       // Allow the old thread to be scheduled again
+       if( Last ) {
+               if( Last->Status == THREAD_STAT_ACTIVE ) {
+                       giFreeTickets += Last->NumTickets;
+                       #if DEBUG_TRACE_TICKETS
+                       LogF(" CPU %i released %p (%s) into the pool (%i tickets in pool)\n",
+                               CPU, Last, Last->ThreadName, Last->NumTickets);
+                       #endif
+               }
+               #if DEBUG_TRACE_TICKETS
+               else
+                       LogF(" %p (%s)->Status = %i\n", Last, Last->ThreadName, Last->Status);
+               #endif
+               Last->CurCPU = -1;
+       }
+       
+       #if 1
+       number = 0;
+       for(thread=gActiveThreads;thread;thread=thread->Next) {
+               if(thread->CurCPU >= 0) continue;
+               number += thread->NumTickets;
+       }
+       if(number != giFreeTickets) {
+               Panic("Bookkeeping fail (giFreeTickets(%i) != number(%i)) - CPU%i",
+                       giFreeTickets, number, CPU);
+       }
+       #endif
+       
+       // No free tickets (all tasks delegated to cores)
+       if( giFreeTickets == 0 ) {
+               SHORTREL(&glThreadListLock);
+               return NULL;
+       }
        
-       //Log(" Threads_GetNextToRun: ticket = %i", ticket);
+       // Get the ticket number
+       ticket = number = rand() % giFreeTickets;
        
        // Find the next thread
        for(thread=gActiveThreads;thread;thread=thread->Next)
        {
+               if(thread->CurCPU >= 0) continue;
                if(thread->NumTickets > number) break;
                number -= thread->NumTickets;
        }
-       
        // Error Check
        if(thread == NULL)
        {
                number = 0;
-               for(thread=gActiveThreads;thread;thread=thread->Next)
+               for(thread=gActiveThreads;thread;thread=thread->Next) {
+                       if(thread->CurCPU >= 0) continue;
                        number += thread->NumTickets;
-               Panic("Bookeeping Failed - giTotalTicketCount (%i) != true count (%i)",
-                       giTotalTickets, number);
+               }
+               Panic("Bookeeping Failed - giFreeTickets(%i) > true count (%i)",
+                       giFreeTickets, number);
        }
+       #if DEBUG_TRACE_TICKETS
+       LogF(" CPU%i giFreeTickets = %i\n", CPU, giFreeTickets);
+       #endif
        
-       //Log_Debug("Threads", "Switching CPU%i to %p (%s)",
-       //      CPU, thread, thread->ThreadName);
+       // Make the new thread non-schedulable
+       giFreeTickets -= thread->NumTickets;    
+       thread->CurCPU = CPU;
+       
+       //Threads_Dump();
+       #if DEBUG_TRACE_TICKETS
+       LogF(" CPU%i giFreeTickets = %i, giving %p (%s CPU=%i)\n",
+               CPU, giFreeTickets, thread, thread->ThreadName, thread->CurCPU);
+       #endif
+       
+       SHORTREL( &glThreadListLock );
        
        return thread;
 }
@@ -742,5 +839,87 @@ void Threads_SegFault(tVAddr Addr)
        //Threads_Exit( 0, -1 );
 }
 
+/**
+ * \brief Acquire a heavy mutex
+ * \param Mutex        Mutex to acquire
+ * 
+ * This type of mutex checks if the mutex is avaliable, and acquires it
+ * if it is. Otherwise, the current thread is added to the mutex's wait
+ * queue and the thread suspends. When the holder of the mutex completes,
+ * the oldest thread (top thread) on the queue is given the lock and
+ * restarted.
+ */
+void Mutex_Acquire(tMutex *Mutex)
+{
+       tThread *us = Proc_GetCurThread();
+       tThread *prev;
+       
+       // Get protector
+       SHORTLOCK( &Mutex->Protector );
+       
+       //Log("Mutex_Acquire: (%p)", Mutex);
+       
+       // Check if the lock is already held
+       if( Mutex->Owner ) {
+               SHORTLOCK( &glThreadListLock );
+               // - Remove from active list
+               us->Remaining = 0;
+               prev = Threads_int_GetPrev(&gActiveThreads, us);
+               prev->Next = us->Next;
+               giNumActiveThreads --;
+               us->Status = THREAD_STAT_SLEEPING;
+               
+               // - Add to waiting
+               if(Mutex->LastWaiting) {
+                       Mutex->LastWaiting->Next = us;
+                       Mutex->LastWaiting = us;
+               }
+               else {
+                       Mutex->Waiting = us;
+                       Mutex->LastWaiting = us;
+               }
+               SHORTREL( &glThreadListLock );
+               SHORTREL( &Mutex->Protector );
+               while(us->Status == THREAD_STAT_SLEEPING)       HALT();
+               // We're only woken when we get the lock
+       }
+       // Ooh, let's take it!
+       else {
+               Mutex->Owner = us;
+               SHORTREL( &Mutex->Protector );
+       }
+}
+
+/**
+ * \brief Release a held mutex
+ * \param Mutex        Mutex to release
+ */
+void Mutex_Release(tMutex *Mutex)
+{
+       SHORTLOCK( &Mutex->Protector );
+       //Log("Mutex_Release: (%p)", Mutex);
+       if( Mutex->Waiting ) {
+               Mutex->Owner = Mutex->Waiting;  // Set owner
+               Mutex->Waiting = Mutex->Waiting->Next;  // Next!
+               // Wake new owner
+               Mutex->Owner->Status = THREAD_STAT_ACTIVE;
+               Threads_AddActive(Mutex->Owner);
+               Log("Mutex %p Woke %p", Mutex, Mutex->Owner);
+       }
+       else {
+               Mutex->Owner = NULL;
+       }
+       SHORTREL( &Mutex->Protector );
+}
+
+/**
+ * \brief Is this mutex locked?
+ * \param Mutex        Mutex pointer
+ */
+int Mutex_IsLocked(tMutex *Mutex)
+{
+       return Mutex->Owner != NULL;
+}
+
 // === EXPORTS ===
 EXPORT(Threads_GetUID);

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