| ------------------------------------------------------------------------------ |
| -- -- |
| -- GNU ADA RUN-TIME LIBRARY (GNARL) COMPONENTS -- |
| -- -- |
| -- S Y S T E M . T A S K _ P R I M I T I V E S -- |
| -- -- |
| -- S p e c -- |
| -- -- |
| -- $Revision$ |
| -- -- |
| -- Copyright (C) 1991-2001, Florida State University -- |
| -- -- |
| -- GNARL is free software; you can redistribute it and/or modify it under -- |
| -- terms of the GNU General Public License as published by the Free Soft- -- |
| -- ware Foundation; either version 2, or (at your option) any later ver- -- |
| -- sion. GNARL is distributed in the hope that it will be useful, but WITH- -- |
| -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- |
| -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License -- |
| -- for more details. You should have received a copy of the GNU General -- |
| -- Public License distributed with GNARL; see file COPYING. If not, write -- |
| -- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, -- |
| -- MA 02111-1307, USA. -- |
| -- -- |
| -- As a special exception, if other files instantiate generics from this -- |
| -- unit, or you link this unit with other files to produce an executable, -- |
| -- this unit does not by itself cause the resulting executable to be -- |
| -- covered by the GNU General Public License. This exception does not -- |
| -- however invalidate any other reasons why the executable file might be -- |
| -- covered by the GNU Public License. -- |
| -- -- |
| -- GNARL was developed by the GNARL team at Florida State University. It is -- |
| -- now maintained by Ada Core Technologies Inc. in cooperation with Florida -- |
| -- State University (http://www.gnat.com). -- |
| -- -- |
| ------------------------------------------------------------------------------ |
| |
| -- RT_GNU/Linux version |
| |
| pragma Polling (Off); |
| -- Turn off polling, we do not want ATC polling to take place during |
| -- tasking operations. It causes infinite loops and other problems. |
| |
| with System.OS_Interface; |
| |
| package System.Task_Primitives is |
| |
| type Lock is limited private; |
| -- Used for implementation of protected objects. |
| |
| type Lock_Ptr is limited private; |
| |
| type RTS_Lock is limited private; |
| -- Used inside the runtime system. The difference between Lock and the |
| -- RTS_Lock is that the later one serves only as a semaphore so that do |
| -- not check for ceiling violations. |
| type RTS_Lock_Ptr is limited private; |
| |
| type Task_Body_Access is access procedure; |
| -- Pointer to the task body's entry point (or possibly a wrapper |
| -- declared local to the GNARL). |
| |
| type Private_Data is limited private; |
| -- Any information that the GNULLI needs maintained on a per-task |
| -- basis. A component of this type is guaranteed to be included |
| -- in the Ada_Task_Control_Block. |
| |
| private |
| |
| type RT_GNU_Linux_Lock is record |
| Ceiling_Priority : System.Any_Priority; |
| Pre_Locking_Priority : System.Any_Priority; |
| -- Used to store the task's active priority before it |
| -- acquires the lock |
| |
| Owner : System.Address; |
| -- This is really a Task_ID, but we can't use that type |
| -- here because this System.Tasking is "with" |
| -- the current package -- a circularity. |
| end record; |
| |
| type Lock is new RT_GNU_Linux_Lock; |
| type RTS_Lock is new RT_GNU_Linux_Lock; |
| |
| type RTS_Lock_Ptr is access all RTS_Lock; |
| type Lock_Ptr is access all Lock; |
| |
| type Private_Data is record |
| Stack : System.Address; |
| -- A stack space needed for the task. the space is allocated |
| -- when the task is being created and is deallocated when |
| -- the TCB for the task is finalized |
| |
| Uses_Fp : Integer; |
| -- A flag to indicate whether the task is going to use floating- |
| -- point unit. It's set to 1, indicating FP unit is always going |
| -- to be used. The reason is that it is in this private record and |
| -- necessary operation has to be provided for a user to call so as |
| -- to change its value |
| |
| Magic : Integer; |
| -- A special value is going to be stored in it when a task is |
| -- created. The value is RT_TASK_MAGIC (16#754d2774#) as declared |
| -- in System.OS_Interface |
| |
| State : System.OS_Interface.Rt_Task_States; |
| -- Shows whether the task is RT_TASK_READY, RT_TASK_DELAYED or |
| -- RT_TASK_DORMANT to support suspend, wait, wakeup. |
| |
| Stack_Bottom : System.Address; |
| |
| Active_Priority : System.Any_Priority; |
| -- Active priority of the task |
| |
| Period : System.OS_Interface.RTIME; |
| -- Intended originally to store the period of the task, but not used |
| -- in the current implementation |
| |
| Resume_Time : System.OS_Interface.RTIME; |
| -- Store the time the task has to be awakened |
| |
| Next : System.Address; |
| -- This really is a Task_ID, used to link the Available_TCBs. |
| |
| Succ : System.Address; |
| pragma Volatile (Succ); |
| Pred : System.Address; |
| pragma Volatile (Pred); |
| -- These really are Task_ID, used to implement a circular doubly |
| -- linked list for task queue |
| |
| L : aliased RTS_Lock; |
| |
| Outer_Lock : RTS_Lock_Ptr := null; |
| -- Used to track which Lock the task is holding is the outermost |
| -- one in order to implement priority setting and inheritance |
| end record; |
| |
| -- ???? May need to use pragma Atomic or Volatile on some |
| -- components; may also need to specify aliased for some. |
| end System.Task_Primitives; |
