text: /**************************************************************************/
  /*                                                                        */
  /*       Copyright (c) Microsoft Corporation. All rights reserved.        */
  /*                                                                        */
  /*       This software is licensed under the Microsoft Software License   */
  /*       Terms for Microsoft Azure RTOS. Full text of the license can be  */
  /*       found in the LICENSE file at https://aka.ms/AzureRTOS_EULA       */
  /*       and in the root directory of this software.                      */
  /*                                                                        */
  /**************************************************************************/
  
  
  /**************************************************************************/
  /**************************************************************************/
  /**                                                                       */
  /** ThreadX Component                                                     */
  /**                                                                       */
  /**   Semaphore                                                           */
  /**                                                                       */
  /**************************************************************************/
  /**************************************************************************/
  
  #define TX_SOURCE_CODE
  
  
  /* Include necessary system files.  */
  
  #include "tx_api.h"
  #include "tx_trace.h"
  #include "tx_thread.h"
  #include "tx_semaphore.h"
  
  
  /**************************************************************************/
  /*                                                                        */
  /*  FUNCTION                                               RELEASE        */
  /*                                                                        */
  /*    _tx_semaphore_delete                                PORTABLE C      */
  /*                                                           6.0          */
  /*  AUTHOR                                                                */
  /*                                                                        */
  /*    William E. Lamie, Microsoft Corporation                             */
  /*                                                                        */
  /*  DESCRIPTION                                                           */
  /*                                                                        */
  /*    This function deletes the specified semaphore.  All threads         */
  /*    suspended on the semaphore are resumed with the TX_DELETED status   */
  /*    code.                                                               */
  /*                                                                        */
  /*  INPUT                                                                 */
  /*                                                                        */
  /*    semaphore_ptr                     Pointer to semaphore control block*/
  /*                                                                        */
  /*  OUTPUT                                                                */
  /*                                                                        */
  /*    TX_SUCCESS                        Successful completion status      */
  /*                                                                        */
  /*  CALLS                                                                 */
  /*                                                                        */
  /*    _tx_thread_system_preempt_check   Check for preemption              */
  /*    _tx_thread_system_resume          Resume thread service             */
  /*    _tx_thread_system_ni_resume       Non-interruptable resume thread   */
  /*                                                                        */
  /*  CALLED BY                                                             */
  /*                                                                        */
  /*    Application Code                                                    */
  /*                                                                        */
  /*  RELEASE HISTORY                                                       */
  /*                                                                        */
  /*    DATE              NAME                      DESCRIPTION             */
  /*                                                                        */
  /*  05-19-2020     William E. Lamie         Initial Version 6.0           */
  /*                                                                        */
  /**************************************************************************/
  UINT  _tx_semaphore_delete(TX_SEMAPHORE *semaphore_ptr)
  {
  
  TX_INTERRUPT_SAVE_AREA
  
  TX_THREAD       *thread_ptr;
  TX_THREAD       *next_thread;
  UINT            suspended_count;
  TX_SEMAPHORE    *next_semaphore;
  TX_SEMAPHORE    *previous_semaphore;
  
  
      /* Disable interrupts to remove the semaphore from the created list.  */
      TX_DISABLE
  
      /* If trace is enabled, insert this event into the trace buffer.  */
      TX_TRACE_IN_LINE_INSERT(TX_TRACE_SEMAPHORE_DELETE, semaphore_ptr, TX_POINTER_TO_ULONG_CONVERT(&thread_ptr), 0, 0, TX_TRACE_SEMAPHORE_EVENTS)
  
      /* Optional semaphore delete extended processing.  */
      TX_SEMAPHORE_DELETE_EXTENSION(semaphore_ptr)
  
      /* If trace is enabled, unregister this object.  */
      TX_TRACE_OBJECT_UNREGISTER(semaphore_ptr)
  
      /* Log this kernel call.  */
      TX_EL_SEMAPHORE_DELETE_INSERT
  
      /* Clear the semaphore ID to make it invalid.  */
      semaphore_ptr -> tx_semaphore_id =  TX_CLEAR_ID;
  
      /* Decrement the number of semaphores.  */
      _tx_semaphore_created_count--;
  
      /* See if the semaphore is the only one on the list.  */
      if (_tx_semaphore_created_count == TX_EMPTY)
      {
  
          /* Only created semaphore, just set the created list to NULL.  */
          _tx_semaphore_created_ptr =  TX_NULL;
      }
      else
      {
  
          /* Link-up the neighbors.  */
          next_semaphore =                                   semaphore_ptr -> tx_semaphore_created_next;
          previous_semaphore =                               semaphore_ptr -> tx_semaphore_created_previous;
          next_semaphore -> tx_semaphore_created_previous =  previous_semaphore;
          previous_semaphore -> tx_semaphore_created_next =  next_semaphore;
  
          /* See if we have to update the created list head pointer.  */
          if (_tx_semaphore_created_ptr == semaphore_ptr)
          {
                      
              /* Yes, move the head pointer to the next link. */
              _tx_semaphore_created_ptr =  next_semaphore;
          }
      }
  
      /* Temporarily disable preemption.  */
      _tx_thread_preempt_disable++;
  
      /* Pickup the suspension information.  */
      thread_ptr =                                     semaphore_ptr -> tx_semaphore_suspension_list;
      semaphore_ptr -> tx_semaphore_suspension_list =  TX_NULL;
      suspended_count =                                semaphore_ptr -> tx_semaphore_suspended_count;
      semaphore_ptr -> tx_semaphore_suspended_count =  TX_NO_SUSPENSIONS;
  
      /* Restore interrupts.  */
      TX_RESTORE
  
      /* Walk through the semaphore list to resume any and all threads suspended
         on this semaphore.  */
      while (suspended_count != TX_NO_SUSPENSIONS)
      {
      
          /* Decrement the suspension count.  */
          suspended_count--;
  
          /* Lockout interrupts.  */
          TX_DISABLE
  
          /* Clear the cleanup pointer, this prevents the timeout from doing 
             anything.  */
          thread_ptr -> tx_thread_suspend_cleanup =  TX_NULL;
  
          /* Set the return status in the thread to TX_DELETED.  */
          thread_ptr -> tx_thread_suspend_status =  TX_DELETED;
  
          /* Move the thread pointer ahead.  */
          next_thread =  thread_ptr -> tx_thread_suspended_next;
  
  #ifdef TX_NOT_INTERRUPTABLE
  
          /* Resume the thread!  */
          _tx_thread_system_ni_resume(thread_ptr);
  
          /* Restore interrupts.  */
          TX_RESTORE
  #else
  
          /* Temporarily disable preemption again.  */
          _tx_thread_preempt_disable++;
  
          /* Restore interrupts.  */
          TX_RESTORE
      
          /* Resume the thread.  */
          _tx_thread_system_resume(thread_ptr);
  #endif
  
          /* Move to next thread.  */
          thread_ptr =  next_thread;
      }
  
      /* Execute Port-Specific completion processing. If needed, it is typically defined in tx_port.h.  */
      TX_SEMAPHORE_DELETE_PORT_COMPLETION(semaphore_ptr)
  
      /* Disable interrupts.  */
      TX_DISABLE
  
      /* Release previous preempt disable.  */
      _tx_thread_preempt_disable--;
  
      /* Restore interrupts.  */
      TX_RESTORE
  
      /* Check for preemption.  */
      _tx_thread_system_preempt_check();
  
      /* Return TX_SUCCESS.  */
      return(TX_SUCCESS);
  }
  
  