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 --          Copyright (C) 1998-2002 Free Software Foundation, Inc.          --
  10 --                                                                          --
  11 -- GNARL is free software; you can  redistribute it  and/or modify it under --
  12 -- terms of the  GNU General Public License as published  by the Free Soft- --
  13 -- ware  Foundation;  either version 2,  or (at your option) any later ver- --
  14 -- sion. GNARL is distributed in the hope that it will be useful, but WITH- --
  15 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  16 -- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
  17 -- for  more details.  You should have  received  a copy of the GNU General --
  18 -- Public License  distributed with GNARL; see file COPYING.  If not, write --
  19 -- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
  20 -- MA 02111-1307, USA.                                                      --
  21 --                                                                          --
  22 -- As a special exception,  if other files  instantiate  generics from this --
  23 -- unit, or you link  this unit with other files  to produce an executable, --
  24 -- this  unit  does not  by itself cause  the resulting  executable  to  be --
  25 -- covered  by the  GNU  General  Public  License.  This exception does not --
  26 -- however invalidate  any other reasons why  the executable file  might be --
  27 -- covered by the  GNU Public License.                                      --
  28 --                                                                          --
  29 -- GNARL was developed by the GNARL team at Florida State University.       --
  30 -- Extensive contributions were provided by Ada Core Technologies, Inc.     --
  31 --                                                                          --
  32 ------------------------------------------------------------------------------
  33
  34 --  This is the OpenVMS/Alpha version of this file
  35
  36 with System.Aux_DEC;
  37
  38 package body System.OS_Primitives is
  39
  40    --------------------------------------
  41    -- Local functions and declarations --
  42    --------------------------------------
  43
  44    function Get_GMToff return Integer;
  45    pragma Import (C, Get_GMToff, "get_gmtoff");
  46    --  Get the offset from GMT for this timezone
  47
  48    VMS_Epoch_Offset : constant Long_Integer :=
  49                         10_000_000 *
  50                           (3_506_716_800 + Long_Integer (Get_GMToff));
  51    --  The offset between the Unix Epoch and the VMS Epoch
  52
  53    subtype Cond_Value_Type is System.Aux_DEC.Unsigned_Longword;
  54    --  Condition Value return type
  55
  56    ----------------
  57    -- Sys_Schdwk --
  58    ----------------
  59    --
  60    --  Schedule Wakeup
  61    --
  62    --  status = returned status
  63    --  pidadr = address of process id to be woken up
  64    --  prcnam = name of process to be woken up
  65    --  daytim = time to wake up
  66    --  reptim = repitition interval of wakeup calls
  67    --
  68
  69    procedure Sys_Schdwk
  70      (
  71       Status : out Cond_Value_Type;
  72       Pidadr : in Address := Null_Address;
  73       Prcnam : in String := String'Null_Parameter;
  74       Daytim : in Long_Integer;
  75       Reptim : in Long_Integer := Long_Integer'Null_Parameter
  76      );
  77
  78    pragma Interface (External, Sys_Schdwk);
  79    --  VMS system call to schedule a wakeup event
  80    pragma Import_Valued_Procedure
  81      (Sys_Schdwk, "SYS$SCHDWK",
  82       (Cond_Value_Type, Address, String,         Long_Integer, Long_Integer),
  83       (Value,           Value,   Descriptor (S), Reference,    Reference)
  84      );
  85
  86    ----------------
  87    -- Sys_Gettim --
  88    ----------------
  89    --
  90    --  Get System Time
  91    --
  92    --  status = returned status
  93    --  tim    = current system time
  94    --
  95
  96    procedure Sys_Gettim
  97      (
  98       Status : out Cond_Value_Type;
  99       Tim    : out OS_Time
 100      );
 101    --  VMS system call to get the current system time
 102    pragma Interface (External, Sys_Gettim);
 103    pragma Import_Valued_Procedure
 104      (Sys_Gettim, "SYS$GETTIM",
 105       (Cond_Value_Type, OS_Time),
 106       (Value,           Reference)
 107      );
 108
 109    ---------------
 110    -- Sys_Hiber --
 111    ---------------
 112
 113    --  Hibernate (until woken up)
 114
 115    --  status = returned status
 116
 117    procedure Sys_Hiber (Status : out Cond_Value_Type);
 118    --  VMS system call to hibernate the current process
 119    pragma Interface (External, Sys_Hiber);
 120    pragma Import_Valued_Procedure
 121      (Sys_Hiber, "SYS$HIBER",
 122       (Cond_Value_Type),
 123       (Value)
 124      );
 125
 126    -----------
 127    -- Clock --
 128    -----------
 129
 130    function OS_Clock return OS_Time is
 131       Status : Cond_Value_Type;
 132       T      : OS_Time;
 133    begin
 134       Sys_Gettim (Status, T);
 135       return (T);
 136    end OS_Clock;
 137
 138    -----------
 139    -- Clock --
 140    -----------
 141
 142    function Clock return Duration is
 143    begin
 144       return To_Duration (OS_Clock, Absolute_Calendar);
 145    end Clock;
 146
 147    ---------------------
 148    -- Monotonic_Clock --
 149    ---------------------
 150
 151    function Monotonic_Clock return Duration renames Clock;
 152
 153    -----------------
 154    -- Timed_Delay --
 155    -----------------
 156
 157    procedure Timed_Delay
 158      (Time : Duration;
 159       Mode : Integer)
 160    is
 161       Sleep_Time : OS_Time;
 162       Status     : Cond_Value_Type;
 163
 164    begin
 165       Sleep_Time := To_OS_Time (Time, Mode);
 166       Sys_Schdwk (Status => Status, Daytim => Sleep_Time);
 167       Sys_Hiber (Status);
 168    end Timed_Delay;
 169
 170    -----------------
 171    -- To_Duration --
 172    -----------------
 173
 174    function To_Duration (T : OS_Time; Mode : Integer) return Duration is
 175       pragma Warnings (Off, Mode);
 176    begin
 177       return Duration'Fixed_Value (T - VMS_Epoch_Offset) * 100;
 178    end To_Duration;
 179
 180    ----------------
 181    -- To_OS_Time --
 182    ----------------
 183
 184    function To_OS_Time (D : Duration; Mode : Integer) return OS_Time is
 185    begin
 186       if Mode = Relative then
 187          return -(Long_Integer'Integer_Value (D) / 100);
 188       else
 189          return Long_Integer'Integer_Value (D) / 100 + VMS_Epoch_Offset;
 190       end if;
 191    end To_OS_Time;
 192
 193 end System.OS_Primitives;