+++ /dev/null
-/*
- * Acess2 Kernel
- * - By John Hodge (thePowersGang)
- *
- * semaphore.c
- * - Semaphores
- */
-#include <acess.h>
-#include <semaphore.h>
-#include <threads_int.h>
-
-#define SEMAPHORE_DEBUG 0 // Debug semaphores
-
-// === CODE ===
-//
-// Initialise a semaphore
-//
-void Semaphore_Init(tSemaphore *Sem, int Value, int MaxValue, const char *Module, const char *Name)
-{
- memset(Sem, 0, sizeof(tSemaphore));
- Sem->Value = Value;
- Sem->ModName = Module;
- Sem->Name = Name;
- Sem->MaxValue = MaxValue;
-}
-//
-// Wait for items to be avaliable
-//
-int Semaphore_Wait(tSemaphore *Sem, int MaxToTake)
-{
- tThread *us;
- int taken;
- if( MaxToTake < 0 ) {
- Log_Warning("Threads", "Semaphore_Wait: User bug - MaxToTake(%i) < 0, Sem=%p(%s)",
- MaxToTake, Sem, Sem->Name);
- }
-
- SHORTLOCK( &Sem->Protector );
-
- // Check if there's already items avaliable
- if( Sem->Value > 0 )
- {
- // Take what we need
- if( MaxToTake && Sem->Value > MaxToTake )
- taken = MaxToTake;
- else
- taken = Sem->Value;
- Sem->Value -= taken;
- }
- else
- {
- SHORTLOCK( &glThreadListLock );
-
- // - Remove from active list
- us = Threads_RemActive();
- us->Next = NULL;
- // - Mark as sleeping
- us->Status = THREAD_STAT_SEMAPHORESLEEP;
- us->WaitPointer = Sem;
- us->RetStatus = MaxToTake; // Use RetStatus as a temp variable
-
- // - Add to waiting
- if(Sem->LastWaiting) {
- Sem->LastWaiting->Next = us;
- Sem->LastWaiting = us;
- }
- else {
- Sem->Waiting = us;
- Sem->LastWaiting = us;
- }
-
- #if DEBUG_TRACE_STATE || SEMAPHORE_DEBUG
- Log("%p (%i %s) waiting on semaphore %p %s:%s",
- us, us->TID, us->ThreadName,
- Sem, Sem->ModName, Sem->Name);
- #endif
-
- SHORTREL( &Sem->Protector ); // Release first to make sure it is released
- SHORTREL( &glThreadListLock );
- while( us->Status == THREAD_STAT_SEMAPHORESLEEP )
- {
- Threads_Yield();
- if(us->Status == THREAD_STAT_SEMAPHORESLEEP)
- Log_Warning("Threads", "Semaphore %p %s:%s re-schedulued while asleep",
- Sem, Sem->ModName, Sem->Name);
- }
- #if DEBUG_TRACE_STATE || SEMAPHORE_DEBUG
- Log("Semaphore %p %s:%s woken", Sem, Sem->ModName, Sem->Name);
- #endif
- // We're only woken when there's something avaliable (or a signal arrives)
- us->WaitPointer = NULL;
-
- taken = us->RetStatus;
-
- // Get the lock again
- SHORTLOCK( &Sem->Protector );
- }
-
- // While there is space, and there are thread waiting
- // wake the first thread and give it what it wants (or what's left)
- while( (Sem->MaxValue == 0 || Sem->Value < Sem->MaxValue) && Sem->Signaling )
- {
- int given;
- tThread *toWake = Sem->Signaling;
-
- Sem->Signaling = Sem->Signaling->Next;
- // Reset ->LastWaiting to NULL if we have just removed the last waiting thread
- if( Sem->Signaling == NULL )
- Sem->LastSignaling = NULL;
-
- // Figure out how much to give
- if( toWake->RetStatus && Sem->Value + toWake->RetStatus < Sem->MaxValue )
- given = toWake->RetStatus;
- else
- given = Sem->MaxValue - Sem->Value;
- Sem->Value -= given;
-
-
- #if DEBUG_TRACE_STATE || SEMAPHORE_DEBUG
- Log("%p (%i %s) woken by wait on %p %s:%s",
- toWake, toWake->TID, toWake->ThreadName,
- Sem, Sem->ModName, Sem->Name);
- #endif
-
- // Save the number we gave to the thread's status
- toWake->RetStatus = given;
-
- // Wake the sleeper
- SHORTLOCK( &glThreadListLock );
- if( toWake->Status != THREAD_STAT_ACTIVE )
- Threads_AddActive(toWake);
- SHORTREL( &glThreadListLock );
- }
- SHORTREL( &Sem->Protector );
-
- #if DEBUG_TRACE_STATE || SEMAPHORE_DEBUG
- Log("Semaphore %p %s:%s took %i by wait",
- Sem, Sem->ModName, Sem->Name, taken);
- #endif
-
- return taken;
-}
-
-//
-// Add items to a semaphore
-//
-int Semaphore_Signal(tSemaphore *Sem, int AmmountToAdd)
-{
- int given;
- int added;
-
- if( AmmountToAdd < 0 ) {
- Log_Warning("Threads", "Semaphore_Signal: User bug - AmmountToAdd(%i) < 0, Sem=%p(%s)",
- AmmountToAdd, Sem, Sem->Name);
- }
- SHORTLOCK( &Sem->Protector );
-
- // Check if we have to block
- if( Sem->MaxValue && Sem->Value == Sem->MaxValue )
- {
- tThread *us;
- #if 0
- Log_Debug("Threads", "Semaphore_Signal: IDLE Sem = %s:%s", Sem->ModName, Sem->Name);
- Log_Debug("Threads", "Semaphore_Signal: Sem->Value(%i) == Sem->MaxValue(%i)", Sem->Value, Sem->MaxValue);
- #endif
-
- SHORTLOCK( &glThreadListLock );
- // - Remove from active list
- us = Threads_RemActive();
- us->Next = NULL;
- // - Mark as sleeping
- us->Status = THREAD_STAT_SEMAPHORESLEEP;
- us->WaitPointer = Sem;
- us->RetStatus = AmmountToAdd; // Use RetStatus as a temp variable
-
- // - Add to waiting
- if(Sem->LastSignaling) {
- Sem->LastSignaling->Next = us;
- Sem->LastSignaling = us;
- }
- else {
- Sem->Signaling = us;
- Sem->LastSignaling = us;
- }
-
- #if DEBUG_TRACE_STATE || SEMAPHORE_DEBUG
- Log("%p (%i %s) signaling semaphore %p %s:%s",
- us, us->TID, us->ThreadName,
- Sem, Sem->ModName, Sem->Name);
- #endif
-
- SHORTREL( &glThreadListLock );
- SHORTREL( &Sem->Protector );
- while(us->Status == THREAD_STAT_SEMAPHORESLEEP) Threads_Yield();
- // We're only woken when there's something avaliable
- us->WaitPointer = NULL;
-
- added = us->RetStatus;
-
- // Get the lock again
- SHORTLOCK( &Sem->Protector );
- }
- // Non blocking
- else
- {
- // Figure out how much we need to take off
- if( Sem->MaxValue && Sem->Value + AmmountToAdd > Sem->MaxValue)
- added = Sem->MaxValue - Sem->Value;
- else
- added = AmmountToAdd;
- Sem->Value += added;
- }
-
- // While there are items avaliable, and there are thread waiting
- // wake the first thread and give it what it wants (or what's left)
- while( Sem->Value && Sem->Waiting )
- {
- tThread *toWake = Sem->Waiting;
-
- // Remove thread from list (double ended, so clear LastWaiting if needed)
- Sem->Waiting = Sem->Waiting->Next;
- if( Sem->Waiting == NULL )
- Sem->LastWaiting = NULL;
-
- // Figure out how much to give to woken thread
- // - Requested count is stored in ->RetStatus
- if( toWake->RetStatus && Sem->Value > toWake->RetStatus )
- given = toWake->RetStatus;
- else
- given = Sem->Value;
- Sem->Value -= given;
-
- // Save the number we gave to the thread's status
- toWake->RetStatus = given;
-
- if(toWake->bInstrTrace)
- Log("%s(%i) given %i from %p", toWake->ThreadName, toWake->TID, given, Sem);
- #if DEBUG_TRACE_STATE || SEMAPHORE_DEBUG
- Log("%p (%i %s) woken by signal on %p %s:%s",
- toWake, toWake->TID, toWake->ThreadName,
- Sem, Sem->ModName, Sem->Name);
- #endif
-
- // Wake the sleeper
- if( toWake->Status != THREAD_STAT_ACTIVE )
- Threads_AddActive(toWake);
- else
- Warning("Thread %p (%i %s) is already awake", toWake, toWake->TID, toWake->ThreadName);
- }
- SHORTREL( &Sem->Protector );
-
- return added;
-}
-
-//
-// Get the current value of a semaphore
-//
-int Semaphore_GetValue(tSemaphore *Sem)
-{
- return Sem->Value;
-}
-
-// === EXPORTS ===
-EXPORT(Semaphore_Init);
-EXPORT(Semaphore_Wait);
-EXPORT(Semaphore_Signal);
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