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------------------------------------------------------------------------------

--                                                                          --

--                 GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS                 --

--                                                                          --

--                  S Y S T E M . O S _ P R I M I T I V E S                 --

--                                                                          --

--                                  B o d y                                 --

--                                                                          --

--          Copyright (C) 1998-2009, 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 3,  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.                                     --

--                                                                          --

-- As a special exception under Section 7 of GPL version 3, you are granted --

-- additional permissions described in the GCC Runtime Library Exception,   --

-- version 3.1, as published by the Free Software Foundation.               --

--                                                                          --

-- You should have received a copy of the GNU General Public License and    --

-- a copy of the GCC Runtime Library Exception along with this program;     --

-- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --

-- <http://www.gnu.org/licenses/>.                                          --

--                                                                          --

-- GNARL was developed by the GNARL team at Florida State University.       --

-- Extensive contributions were provided by Ada Core Technologies, Inc.     --

--                                                                          --

------------------------------------------------------------------------------

--  This is the OpenVMS/Alpha version of this file

with System.Aux_DEC;

package body System.OS_Primitives is

   --------------------------------------

   -- Local functions and declarations --

   --------------------------------------

   function Get_GMToff return Integer;

   pragma Import (C, Get_GMToff, "get_gmtoff");

   --  Get the offset from GMT for this timezone

   function VMS_Epoch_Offset return Long_Integer;

   pragma Inline (VMS_Epoch_Offset);

   --  The offset between the Unix Epoch and the VMS Epoch

   subtype Cond_Value_Type is System.Aux_DEC.Unsigned_Longword;

   --  Condition Value return type

   ----------------------

   -- VMS_Epoch_Offset --

   ----------------------

   function VMS_Epoch_Offset return Long_Integer is

   begin

      return 10_000_000 * (3_506_716_800 + Long_Integer (Get_GMToff));

   end VMS_Epoch_Offset;

   ----------------

   -- Sys_Schdwk --

   ----------------

   --

   --  Schedule Wakeup

   --

   --  status = returned status

   --  pidadr = address of process id to be woken up

   --  prcnam = name of process to be woken up

   --  daytim = time to wake up

   --  reptim = repetition interval of wakeup calls

   --

   procedure Sys_Schdwk

     (

      Status : out Cond_Value_Type;

      Pidadr : Address := Null_Address;

      Prcnam : String := String'Null_Parameter;

      Daytim : Long_Integer;

      Reptim : Long_Integer := Long_Integer'Null_Parameter

     );

   pragma Interface (External, Sys_Schdwk);

   --  VMS system call to schedule a wakeup event

   pragma Import_Valued_Procedure

     (Sys_Schdwk, "SYS$SCHDWK",

      (Cond_Value_Type, Address, String,         Long_Integer, Long_Integer),

      (Value,           Value,   Descriptor (S), Reference,    Reference)

     );

   ----------------

   -- Sys_Gettim --

   ----------------

   --

   --  Get System Time

   --

   --  status = returned status

   --  tim    = current system time

   --

   procedure Sys_Gettim

     (

      Status : out Cond_Value_Type;

      Tim    : out OS_Time

     );

   --  VMS system call to get the current system time

   pragma Interface (External, Sys_Gettim);

   pragma Import_Valued_Procedure

     (Sys_Gettim, "SYS$GETTIM",

      (Cond_Value_Type, OS_Time),

      (Value,           Reference)

     );

   ---------------

   -- Sys_Hiber --

   ---------------

   --  Hibernate (until woken up)

   --  status = returned status

   procedure Sys_Hiber (Status : out Cond_Value_Type);

   --  VMS system call to hibernate the current process

   pragma Interface (External, Sys_Hiber);

   pragma Import_Valued_Procedure

     (Sys_Hiber, "SYS$HIBER",

      (Cond_Value_Type),

      (Value)

     );

   -----------

   -- Clock --

   -----------

   function OS_Clock return OS_Time is

      Status : Cond_Value_Type;

      T      : OS_Time;

   begin

      Sys_Gettim (Status, T);

      return (T);

   end OS_Clock;

   -----------

   -- Clock --

   -----------

   function Clock return Duration is

   begin

      return To_Duration (OS_Clock, Absolute_Calendar);

   end Clock;

   ----------------

   -- Initialize --

   ----------------

   procedure Initialize is

   begin

      null;

   end Initialize;

   ---------------------

   -- Monotonic_Clock --

   ---------------------

   function Monotonic_Clock return Duration renames Clock;

   -----------------

   -- Timed_Delay --

   -----------------

   procedure Timed_Delay

     (Time : Duration;

      Mode : Integer)

   is

      Sleep_Time : OS_Time;

      Status     : Cond_Value_Type;

      pragma Unreferenced (Status);

   begin

      Sleep_Time := To_OS_Time (Time, Mode);

      Sys_Schdwk (Status => Status, Daytim => Sleep_Time);

      Sys_Hiber (Status);

   end Timed_Delay;

   -----------------

   -- To_Duration --

   -----------------

   function To_Duration (T : OS_Time; Mode : Integer) return Duration is

      pragma Warnings (Off, Mode);

   begin

      return Duration'Fixed_Value (T - VMS_Epoch_Offset) * 100;

   end To_Duration;

   ----------------

   -- To_OS_Time --

   ----------------

   function To_OS_Time (D : Duration; Mode : Integer) return OS_Time is

   begin

      if Mode = Relative then

         return -(Long_Integer'Integer_Value (D) / 100);

      else

         return Long_Integer'Integer_Value (D) / 100 + VMS_Epoch_Offset;

      end if;

   end To_OS_Time;

end System.OS_Primitives;