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Diffstat (limited to 'gcc/ada/4zsytaco.adb')
| -rw-r--r-- | gcc/ada/4zsytaco.adb | 142 |
1 files changed, 142 insertions, 0 deletions
diff --git a/gcc/ada/4zsytaco.adb b/gcc/ada/4zsytaco.adb new file mode 100644 index 00000000000..2bc02353ace --- /dev/null +++ b/gcc/ada/4zsytaco.adb @@ -0,0 +1,142 @@ +------------------------------------------------------------------------------ +-- -- +-- GNAT RUNTIME COMPONENTS -- +-- -- +-- A D A . S Y N C H R O N O U S _ T A S K _ C O N T R O L -- +-- -- +-- B o d y -- +-- -- +-- $Revision: 1.1 $ +-- -- +-- Copyright (C) 1992-2001 Free Software Foundation, Inc. -- +-- -- +-- GNAT 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. GNAT 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 GNAT; 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. -- +-- -- +-- GNAT was originally developed by the GNAT team at New York University. -- +-- It is now maintained by Ada Core Technologies Inc (http://www.gnat.com). -- +-- -- +------------------------------------------------------------------------------ + +with Interfaces.C; +package body Ada.Synchronous_Task_Control is + use System.OS_Interface; + use type Interfaces.C.int; + + ------------------- + -- Current_State -- + ------------------- + + function Current_State (S : Suspension_Object) return Boolean is + St : STATUS; + Result : Boolean := False; + + begin + -- Determine state by attempting to take the semaphore with + -- a 0 timeout value. Status = OK indicates the semaphore was + -- full, so reset it to the full state. + + St := semTake (S.Sema, NO_WAIT); + + if St = OK then + -- Took the semaphore. Reset semaphore state to FULL + Result := True; + St := semGive (S.Sema); + end if; + + return Result; + end Current_State; + + --------------- + -- Set_False -- + --------------- + + procedure Set_False (S : in out Suspension_Object) is + St : STATUS; + begin + -- Need to get the semaphore into the "empty" state. + -- On return, this task will have made the semaphore + -- empty (St = OK) or have left it empty. + St := semTake (S.Sema, NO_WAIT); + end Set_False; + + -------------- + -- Set_True -- + -------------- + + procedure Set_True (S : in out Suspension_Object) is + St : STATUS; + begin + St := semGive (S.Sema); + end Set_True; + + ------------------------ + -- Suspend_Until_True -- + ------------------------ + + procedure Suspend_Until_True (S : in out Suspension_Object) is + St : STATUS; + + -- Declare local exception so the mutex can still be reset + -- to full if Program_Error is raised + + Task_Already_Pending : exception; + begin + -- Determine whether another task is pending on the suspension + -- object. Should never be called from an ISR. Therefore semTake can + -- be called on the mutex + St := semTake (S.Mutex, NO_WAIT); + + if St = OK then + -- Wait for suspension object + + St := semTake (S.Sema, WAIT_FOREVER); + St := semGive (S.Mutex); + + else + -- Another task is pending on the suspension object + + raise Task_Already_Pending; + end if; + exception + when Task_Already_Pending => + raise Program_Error; + when others => + St := semGive (S.Mutex); + raise; + end Suspend_Until_True; + + procedure Initialize (S : in out Suspension_Object) is + begin + S.Sema := semBCreate (SEM_Q_FIFO, SEM_EMPTY); + + -- Use simpler binary semaphore instead of VxWorks + -- mutual exclusion semaphore, because we don't need + -- the fancier semantics and their overhead. + + S.Mutex := semBCreate (SEM_Q_FIFO, SEM_FULL); + end Initialize; + + procedure Finalize (S : in out Suspension_Object) is + St : STATUS; + begin + St := semDelete (S.Sema); + St := semDelete (S.Mutex); + end Finalize; + +end Ada.Synchronous_Task_Control; |