Kernel/events.c

   1 /*
   2  * Acess2 Kernel
   3  * - By John Hodge (thePowersGang)
   4  *
   5  * events.c
   6  * - Thread level event handling
   7  */
   8 #define DEBUG   0
   9 #include <acess.h>
  10 #include <threads_int.h>
  11 #include <events.h>
  12
  13 // === CODE ===
  14 void Threads_PostEvent(tThread *Thread, Uint32 EventMask)
  15 {
  16         // Sanity checking
  17         if( !Thread )   return ;
  18         if( EventMask == 0 )    return ;
  19         // TODO: Check that only one bit is set?
  20
  21         ENTER("pThread xEventMask", Thread, EventMask);
  22
  23         SHORTLOCK( &Thread->IsLocked );
  24
  25         Thread->EventState |= EventMask;
  26         LOG("Thread->EventState = 0x%x", Thread->EventState);
  27
  28         // Currently sleeping on an event?
  29         if( Thread->Status == THREAD_STAT_EVENTSLEEP )
  30         {
  31                 // Waiting on this event?
  32                 if( (Uint32)Thread->RetStatus & EventMask )
  33                 {
  34                         // Wake up
  35                         // TODO: Does it matter if the thread is locked here?
  36                         LOG("Waking thread %p(%i %s)", Thread, Thread->TID, Thread->ThreadName);
  37                         Threads_AddActive(Thread);
  38                 }
  39         }
  40
  41         SHORTREL( &Thread->IsLocked );
  42         LEAVE('-');
  43 }
  44
  45 /**
  46  * \brief Wait for an event to occur
  47  */
  48 Uint32 Threads_WaitEvents(Uint32 EventMask)
  49 {
  50         Uint32  rv;
  51         tThread *us = Proc_GetCurThread();
  52
  53         ENTER("xEventMask", EventMask);
  54
  55         // Early return check
  56         if( EventMask == 0 )
  57         {
  58                 LEAVE('i', 0);
  59                 return 0;
  60         }
  61
  62         LOG("us = %p(%i %s)", us, us->TID, us->ThreadName);
  63
  64         // Check if a wait is needed
  65         SHORTLOCK( &us->IsLocked );
  66         while( !(us->EventState & EventMask) )
  67         {
  68                 LOG("Locked and preparing for wait");
  69                 // Wait
  70                 us->RetStatus = EventMask;      // HACK: Store EventMask in RetStatus
  71                 SHORTLOCK( &glThreadListLock );
  72                 us = Threads_RemActive();
  73                 us->Status = THREAD_STAT_EVENTSLEEP;
  74                 // Note stored anywhere because we're woken using other means
  75                 SHORTREL( &glThreadListLock );
  76                 SHORTREL( &us->IsLocked );
  77                 while(us->Status == THREAD_STAT_EVENTSLEEP)     Threads_Yield();
  78                 // Woken when lock is acquired
  79                 SHORTLOCK( &us->IsLocked );
  80         }
  81
  82         // Get return value and clear changed event bits
  83         rv = us->EventState & EventMask;
  84         us->EventState &= ~EventMask;
  85
  86         SHORTREL( &us->IsLocked );
  87
  88         LEAVE('x', rv);
  89         return rv;
  90 }
  91