gcc/ada/5vosprim.adb

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                GNU ADA RUN-TIME LIBRARY (GNARL) COMPONENTS               --
   4 --                                                                          --
   5 --                  S Y S T E M . O S _ P R I M I T I V E S                 --
   6 --                                                                          --
   7 --                                  B o d y                                 --
   8 --                                                                          --
   9 --                             $Revision: 1.2 $
  10 --                                                                          --
  11 --          Copyright (C) 1998-2001 Free Software Foundation, Inc.          --
  12 --                                                                          --
  13 -- GNARL is free software; you can  redistribute it  and/or modify it under --
  14 -- terms of the  GNU General Public License as published  by the Free Soft- --
  15 -- ware  Foundation;  either version 2,  or (at your option) any later ver- --
  16 -- sion. GNARL is distributed in the hope that it will be useful, but WITH- --
  17 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  18 -- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
  19 -- for  more details.  You should have  received  a copy of the GNU General --
  20 -- Public License  distributed with GNARL; see file COPYING.  If not, write --
  21 -- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
  22 -- MA 02111-1307, USA.                                                      --
  23 --                                                                          --
  24 -- As a special exception,  if other files  instantiate  generics from this --
  25 -- unit, or you link  this unit with other files  to produce an executable, --
  26 -- this  unit  does not  by itself cause  the resulting  executable  to  be --
  27 -- covered  by the  GNU  General  Public  License.  This exception does not --
  28 -- however invalidate  any other reasons why  the executable file  might be --
  29 -- covered by the  GNU Public License.                                      --
  30 --                                                                          --
  31 -- GNARL was developed by the GNARL team at Florida State University. It is --
  32 -- now maintained by Ada Core Technologies Inc. in cooperation with Florida --
  33 -- State University (http://www.gnat.com).                                  --
  34 --                                                                          --
  35 ------------------------------------------------------------------------------
  36
  37 --  This is the OpenVMS/Alpha version of this file
  38
  39 with System.Aux_DEC;
  40
  41 package body System.OS_Primitives is
  42
  43    --------------------------------------
  44    -- Local functions and declarations --
  45    --------------------------------------
  46
  47    function Get_GMToff return Integer;
  48    pragma Import (C, Get_GMToff, "get_gmtoff");
  49    --  Get the offset from GMT for this timezone
  50
  51    VMS_Epoch_Offset : constant Long_Integer :=
  52                         10_000_000 *
  53                           (3_506_716_800 + Long_Integer (Get_GMToff));
  54    --  The offset between the Unix Epoch and the VMS Epoch
  55
  56    subtype Cond_Value_Type is System.Aux_DEC.Unsigned_Longword;
  57    --  Condition Value return type
  58
  59    ----------------
  60    -- Sys_Schdwk --
  61    ----------------
  62    --
  63    --  Schedule Wakeup
  64    --
  65    --  status = returned status
  66    --  pidadr = address of process id to be woken up
  67    --  prcnam = name of process to be woken up
  68    --  daytim = time to wake up
  69    --  reptim = repitition interval of wakeup calls
  70    --
  71
  72    procedure Sys_Schdwk
  73      (
  74       Status : out Cond_Value_Type;
  75       Pidadr : in Address := Null_Address;
  76       Prcnam : in String := String'Null_Parameter;
  77       Daytim : in Long_Integer;
  78       Reptim : in Long_Integer := Long_Integer'Null_Parameter
  79      );
  80
  81    pragma Interface (External, Sys_Schdwk);
  82    --  VMS system call to schedule a wakeup event
  83    pragma Import_Valued_Procedure
  84      (Sys_Schdwk, "SYS$SCHDWK",
  85       (Cond_Value_Type, Address, String,         Long_Integer, Long_Integer),
  86       (Value,           Value,   Descriptor (S), Reference,    Reference)
  87      );
  88
  89    ----------------
  90    -- Sys_Gettim --
  91    ----------------
  92    --
  93    --  Get System Time
  94    --
  95    --  status = returned status
  96    --  tim    = current system time
  97    --
  98
  99    procedure Sys_Gettim
 100      (
 101       Status : out Cond_Value_Type;
 102       Tim    : out OS_Time
 103      );
 104    --  VMS system call to get the current system time
 105    pragma Interface (External, Sys_Gettim);
 106    pragma Import_Valued_Procedure
 107      (Sys_Gettim, "SYS$GETTIM",
 108       (Cond_Value_Type, OS_Time),
 109       (Value,           Reference)
 110      );
 111
 112    ---------------
 113    -- Sys_Hiber --
 114    ---------------
 115    --
 116    --  Hibernate (until woken up)
 117    --
 118    --  status = returned status
 119    --
 120
 121    procedure Sys_Hiber (Status : out Cond_Value_Type);
 122    --  VMS system call to hibernate the current process
 123    pragma Interface (External, Sys_Hiber);
 124    pragma Import_Valued_Procedure
 125      (Sys_Hiber, "SYS$HIBER",
 126       (Cond_Value_Type),
 127       (Value)
 128      );
 129
 130    -----------
 131    -- Clock --
 132    -----------
 133
 134    function OS_Clock return OS_Time is
 135       Status : Cond_Value_Type;
 136       T      : OS_Time;
 137    begin
 138       Sys_Gettim (Status, T);
 139       return (T);
 140    end OS_Clock;
 141
 142    -----------
 143    -- Clock --
 144    -----------
 145
 146    function Clock return Duration is
 147    begin
 148       return To_Duration (OS_Clock, Absolute_Calendar);
 149    end Clock;
 150
 151    ---------------------
 152    -- Monotonic_Clock --
 153    ---------------------
 154
 155    function Monotonic_Clock return Duration renames Clock;
 156
 157    -----------------
 158    -- Timed_Delay --
 159    -----------------
 160
 161    procedure Timed_Delay
 162      (Time : Duration;
 163       Mode : Integer)
 164    is
 165       Sleep_Time : OS_Time;
 166       Status     : Cond_Value_Type;
 167
 168    begin
 169       Sleep_Time := To_OS_Time (Time, Mode);
 170       Sys_Schdwk (Status => Status, Daytim => Sleep_Time);
 171       Sys_Hiber (Status);
 172    end Timed_Delay;
 173
 174    -----------------
 175    -- To_Duration --
 176    -----------------
 177
 178    function To_Duration (T : OS_Time; Mode : Integer) return Duration is
 179    begin
 180       return Duration'Fixed_Value (T - VMS_Epoch_Offset) * 100;
 181    end To_Duration;
 182
 183    ----------------
 184    -- To_OS_Time --
 185    ----------------
 186
 187    function To_OS_Time (D : Duration; Mode : Integer) return OS_Time is
 188    begin
 189       if Mode = Relative then
 190          return -(Long_Integer'Integer_Value (D) / 100);
 191       else
 192          return Long_Integer'Integer_Value (D) / 100 + VMS_Epoch_Offset;
 193       end if;
 194    end To_OS_Time;
 195
 196 end System.OS_Primitives;