diff options
Diffstat (limited to 'gcc-4.2.1/gcc/ada/a-dynpri.adb')
| -rw-r--r-- | gcc-4.2.1/gcc/ada/a-dynpri.adb | 162 |
1 files changed, 162 insertions, 0 deletions
diff --git a/gcc-4.2.1/gcc/ada/a-dynpri.adb b/gcc-4.2.1/gcc/ada/a-dynpri.adb new file mode 100644 index 000000000..82da81552 --- /dev/null +++ b/gcc-4.2.1/gcc/ada/a-dynpri.adb @@ -0,0 +1,162 @@ +------------------------------------------------------------------------------ +-- -- +-- GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS -- +-- -- +-- A D A . D Y N A M I C _ P R I O R I T I E S -- +-- -- +-- B o d y -- +-- -- +-- Copyright (C) 1992-2006, Free Software Foundation, Inc. -- +-- -- +-- 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, 51 Franklin Street, Fifth Floor, -- +-- Boston, MA 02110-1301, 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. -- +-- Extensive contributions were provided by Ada Core Technologies, Inc. -- +-- -- +------------------------------------------------------------------------------ + +with System.Task_Primitives.Operations; +-- used for Write_Lock +-- Unlock +-- Set_Priority +-- Wakeup +-- Self + +with System.Tasking; +-- used for Task_Id + +with System.Parameters; +-- used for Single_Lock + +with System.Soft_Links; +-- use for Abort_Defer +-- Abort_Undefer + +with Unchecked_Conversion; + +package body Ada.Dynamic_Priorities is + + package STPO renames System.Task_Primitives.Operations; + package SSL renames System.Soft_Links; + + use System.Parameters; + use System.Tasking; + + function Convert_Ids is new + Unchecked_Conversion + (Task_Identification.Task_Id, System.Tasking.Task_Id); + + ------------------ + -- Get_Priority -- + ------------------ + + -- Inquire base priority of a task + + function Get_Priority + (T : Ada.Task_Identification.Task_Id := + Ada.Task_Identification.Current_Task) return System.Any_Priority + is + Target : constant Task_Id := Convert_Ids (T); + Error_Message : constant String := "Trying to get the priority of a "; + + begin + if Target = Convert_Ids (Ada.Task_Identification.Null_Task_Id) then + raise Program_Error with Error_Message & "null task"; + end if; + + if Task_Identification.Is_Terminated (T) then + raise Tasking_Error with Error_Message & "null task"; + end if; + + return Target.Common.Base_Priority; + end Get_Priority; + + ------------------ + -- Set_Priority -- + ------------------ + + -- Change base priority of a task dynamically + + procedure Set_Priority + (Priority : System.Any_Priority; + T : Ada.Task_Identification.Task_Id := + Ada.Task_Identification.Current_Task) + is + Target : constant Task_Id := Convert_Ids (T); + Self_ID : constant Task_Id := STPO.Self; + Error_Message : constant String := "Trying to set the priority of a "; + + begin + if Target = Convert_Ids (Ada.Task_Identification.Null_Task_Id) then + raise Program_Error with Error_Message & "null task"; + end if; + + if Task_Identification.Is_Terminated (T) then + raise Tasking_Error with Error_Message & "terminated task"; + end if; + + SSL.Abort_Defer.all; + + if Single_Lock then + STPO.Lock_RTS; + end if; + + STPO.Write_Lock (Target); + + if Self_ID = Target then + Target.Common.Base_Priority := Priority; + STPO.Set_Priority (Target, Priority); + + STPO.Unlock (Target); + + if Single_Lock then + STPO.Unlock_RTS; + end if; + + -- Yield is needed to enforce FIFO task dispatching + + -- LL Set_Priority is made while holding the RTS lock so that it + -- is inheriting high priority until it release all the RTS locks. + + -- If this is used in a system where Ceiling Locking is + -- not enforced we may end up getting two Yield effects. + + STPO.Yield; + + else + Target.New_Base_Priority := Priority; + Target.Pending_Priority_Change := True; + Target.Pending_Action := True; + + STPO.Wakeup (Target, Target.Common.State); + + -- If the task is suspended, wake it up to perform the change. + -- check for ceiling violations ??? + + STPO.Unlock (Target); + + if Single_Lock then + STPO.Unlock_RTS; + end if; + end if; + + SSL.Abort_Undefer.all; + end Set_Priority; + +end Ada.Dynamic_Priorities; |