------------------------------------------------------------------------------
--                                                                          --
--                GNU ADA RUN-TIME LIBRARY (GNARL) COMPONENTS               --
--                                                                          --
--           S Y S T E M . I N T E R R U P T _ M A N A G E M E N T .        --
--                           O P E R A T I O N S                            --
--                                                                          --
--                                  B o d y                                 --
--                                                                          --
--                             $Revision: 1.8 $                             --
--                                                                          --
--             Copyright (C) 1991-2000 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).                                  --
--                                                                          --
------------------------------------------------------------------------------

--  This is a OpenVMS/Alpha version of this package.

with System.OS_Interface;
--  used for various type, constant, and operations

with System.Tasking;

with System.Tasking.Initialization;

with System.Task_Primitives.Operations;

with System.Task_Primitives.Operations.DEC;

with Unchecked_Conversion;

package body System.Interrupt_Management.Operations is

   use System.OS_Interface;
   use System.Tasking;
   use type unsigned_short;

   function To_Address is new Unchecked_Conversion (Task_ID, System.Address);
   function To_Task_ID is new Unchecked_Conversion (System.Address, Task_ID);
   package POP renames System.Task_Primitives.Operations;

   ----------------------------
   -- Thread_Block_Interrupt --
   ----------------------------

   procedure Thread_Block_Interrupt (Interrupt : Interrupt_ID) is
   begin
      null;
   end Thread_Block_Interrupt;

   ------------------------------
   -- Thread_Unblock_Interrupt --
   ------------------------------

   procedure Thread_Unblock_Interrupt (Interrupt : Interrupt_ID) is
   begin
      null;
   end Thread_Unblock_Interrupt;

   ------------------------
   -- Set_Interrupt_Mask --
   ------------------------

   procedure Set_Interrupt_Mask (Mask : access Interrupt_Mask) is
   begin
      null;
   end Set_Interrupt_Mask;

   procedure Set_Interrupt_Mask
     (Mask  : access Interrupt_Mask;
      OMask : access Interrupt_Mask) is
   begin
      null;
   end Set_Interrupt_Mask;

   ------------------------
   -- Get_Interrupt_Mask --
   ------------------------

   procedure Get_Interrupt_Mask (Mask : access Interrupt_Mask) is
   begin
      null;
   end Get_Interrupt_Mask;

   --------------------
   -- Interrupt_Wait --
   --------------------

   function To_unsigned_long is new
     Unchecked_Conversion (System.Address, unsigned_long);

   function Interrupt_Wait (Mask : access Interrupt_Mask)
     return Interrupt_ID
   is
      Self_ID : Task_ID := Self;
      Iosb    : IO_Status_Block_Type := (0, 0, 0);
      Status  : Cond_Value_Type;

   begin

      --  A QIO read is registered. The system call returns immediately
      --  after scheduling an AST to be fired when the operation
      --  completes.

      Sys_QIO
        (Status => Status,
         Chan   => Rcv_Interrupt_Chan,
         Func   => IO_READVBLK,
         Iosb   => Iosb,
         Astadr =>
           POP.DEC.Interrupt_AST_Handler'Access,
         Astprm => To_Address (Self_ID),
         P1     => To_unsigned_long (Interrupt_Mailbox'Address),
         P2     => Interrupt_ID'Size / 8);

      pragma Assert ((Status and 1) = 1);

      loop

         --  Wait to be woken up. Could be that the AST has fired,
         --  in which case the Iosb.Status variable will be non-zero,
         --  or maybe the wait is being aborted.

         POP.Sleep
           (Self_ID,
            System.Tasking.Interrupt_Server_Blocked_On_Event_Flag);

         if Iosb.Status /= 0 then
            if (Iosb.Status and 1) = 1
              and then Mask (Signal (Interrupt_Mailbox))
            then
               return Interrupt_Mailbox;
            else
               return 0;
            end if;
         else
            POP.Unlock (Self_ID);
            System.Tasking.Initialization.Undefer_Abort (Self_ID);
            System.Tasking.Initialization.Defer_Abort (Self_ID);
            POP.Write_Lock (Self_ID);
         end if;
      end loop;
   end Interrupt_Wait;

   ----------------------------
   -- Install_Default_Action --
   ----------------------------

   procedure Install_Default_Action (Interrupt : Interrupt_ID) is
   begin
      null;
   end Install_Default_Action;

   ---------------------------
   -- Install_Ignore_Action --
   ---------------------------

   procedure Install_Ignore_Action (Interrupt : Interrupt_ID) is
   begin
      null;
   end Install_Ignore_Action;

   -------------------------
   -- Fill_Interrupt_Mask --
   -------------------------

   procedure Fill_Interrupt_Mask (Mask : access Interrupt_Mask) is
   begin
      Mask.all := (others => True);
   end Fill_Interrupt_Mask;

   --------------------------
   -- Empty_Interrupt_Mask --
   --------------------------

   procedure Empty_Interrupt_Mask (Mask : access Interrupt_Mask) is
   begin
      Mask.all := (others => False);
   end Empty_Interrupt_Mask;

   ---------------------------
   -- Add_To_Interrupt_Mask --
   ---------------------------

   procedure Add_To_Interrupt_Mask
     (Mask      : access Interrupt_Mask;
      Interrupt : Interrupt_ID)
   is
   begin
      Mask (Signal (Interrupt)) := True;
   end Add_To_Interrupt_Mask;

   --------------------------------
   -- Delete_From_Interrupt_Mask --
   --------------------------------

   procedure Delete_From_Interrupt_Mask
     (Mask      : access Interrupt_Mask;
      Interrupt : Interrupt_ID)
   is
   begin
      Mask (Signal (Interrupt)) := False;
   end Delete_From_Interrupt_Mask;

   ---------------
   -- Is_Member --
   ---------------

   function Is_Member
     (Mask      : access Interrupt_Mask;
      Interrupt : Interrupt_ID) return Boolean
   is
   begin
      return Mask (Signal (Interrupt));
   end Is_Member;

   -------------------------
   -- Copy_Interrupt_Mask --
   -------------------------

   procedure Copy_Interrupt_Mask
     (X : out Interrupt_Mask;
      Y : Interrupt_Mask)
   is
   begin
      X := Y;
   end Copy_Interrupt_Mask;

   -------------------------
   -- Interrupt_Self_Process --
   -------------------------

   procedure Interrupt_Self_Process (Interrupt : Interrupt_ID) is
      Status : Cond_Value_Type;
   begin
      Sys_QIO
        (Status => Status,
         Chan   => Snd_Interrupt_Chan,
         Func   => IO_WRITEVBLK,
         P1     => To_unsigned_long (Interrupt'Address),
         P2     => Interrupt_ID'Size / 8);

      pragma Assert ((Status and 1) = 1);

   end Interrupt_Self_Process;

begin

   Environment_Mask := (others => False);
   All_Tasks_Mask := (others => True);

   for I in Interrupt_ID loop
      if Keep_Unmasked (I) then
         Environment_Mask (Signal (I)) := True;
         All_Tasks_Mask (Signal (I)) := False;
      end if;
   end loop;

end System.Interrupt_Management.Operations;