KernelLand/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                         LOG("Waking thread %p(%i %s)", Thread, Thread->TID, Thread->ThreadName);
  36                         Threads_AddActive(Thread);
  37                 }
  38         }
  39
  40         SHORTREL( &Thread->IsLocked );
  41         LEAVE('-');
  42 }
  43
  44 /**
  45  * \brief Clear an event without waiting
  46  */
  47 void Threads_ClearEvent(Uint32 EventMask)
  48 {
  49         Proc_GetCurThread()->EventState &= ~EventMask;
  50 }
  51
  52 /**
  53  * \brief Wait for an event to occur
  54  */
  55 Uint32 Threads_WaitEvents(Uint32 EventMask)
  56 {
  57         Uint32  rv;
  58         tThread *us = Proc_GetCurThread();
  59
  60         ENTER("xEventMask", EventMask);
  61
  62         // Early return check
  63         if( EventMask == 0 )
  64         {
  65                 LEAVE('i', 0);
  66                 return 0;
  67         }
  68
  69         LOG("us = %p(%i %s)", us, us->TID, us->ThreadName);
  70
  71         // Check if a wait is needed
  72         SHORTLOCK( &us->IsLocked );
  73         while( !(us->EventState & EventMask) )
  74         {
  75                 LOG("Locked and preparing for wait");
  76                 // Wait
  77                 us->RetStatus = EventMask;      // HACK: Store EventMask in RetStatus
  78                 SHORTLOCK( &glThreadListLock );
  79                 us = Threads_RemActive();
  80                 us->Status = THREAD_STAT_EVENTSLEEP;
  81                 // Note stored anywhere because we're woken using other means
  82                 SHORTREL( &glThreadListLock );
  83                 SHORTREL( &us->IsLocked );
  84                 while(us->Status == THREAD_STAT_EVENTSLEEP)     Threads_Yield();
  85                 // Woken when lock is acquired
  86                 SHORTLOCK( &us->IsLocked );
  87         }
  88
  89         // Get return value and clear changed event bits
  90         rv = us->EventState & EventMask;
  91         us->EventState &= ~EventMask;
  92
  93         SHORTREL( &us->IsLocked );
  94
  95         LEAVE('x', rv);
  96         return rv;
  97 }
  98