gcc/ada/s-osprim-vxworks.adb

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                 GNAT 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) 1998-2009, 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 3,  or (at your option) any later ver- --
  14 -- sion.  GNAT 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.                                     --
  17 --                                                                          --
  18 -- As a special exception under Section 7 of GPL version 3, you are granted --
  19 -- additional permissions described in the GCC Runtime Library Exception,   --
  20 -- version 3.1, as published by the Free Software Foundation.               --
  21 --                                                                          --
  22 -- You should have received a copy of the GNU General Public License and    --
  23 -- a copy of the GCC Runtime Library Exception along with this program;     --
  24 -- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
  25 -- <http://www.gnu.org/licenses/>.                                          --
  26 --                                                                          --
  27 -- GNARL was developed by the GNARL team at Florida State University.       --
  28 -- Extensive contributions were provided by Ada Core Technologies, Inc.     --
  29 --                                                                          --
  30 ------------------------------------------------------------------------------
  31
  32 --  This version is for VxWorks targets
  33
  34 with System.OS_Interface;
  35 --  Since the thread library is part of the VxWorks kernel, using OS_Interface
  36 --  is not a problem here, as long as we only use System.OS_Interface as a
  37 --  set of C imported routines: using Ada routines from this package would
  38 --  create a dependency on libgnarl in libgnat, which is not desirable.
  39
  40 with Interfaces.C;
  41
  42 package body System.OS_Primitives is
  43
  44    use System.OS_Interface;
  45    use type Interfaces.C.int;
  46
  47    ------------------------
  48    -- Internal functions --
  49    ------------------------
  50
  51    function To_Clock_Ticks (D : Duration) return int;
  52    --  Convert a duration value (in seconds) into clock ticks.
  53    --  Note that this routine is duplicated from System.OS_Interface since
  54    --  as explained above, we do not want to depend on libgnarl
  55
  56    function To_Clock_Ticks (D : Duration) return int is
  57       Ticks          : Long_Long_Integer;
  58       Rate_Duration  : Duration;
  59       Ticks_Duration : Duration;
  60
  61    begin
  62       if D < 0.0 then
  63          return -1;
  64       end if;
  65
  66       --  Ensure that the duration can be converted to ticks
  67       --  at the current clock tick rate without overflowing.
  68
  69       Rate_Duration := Duration (sysClkRateGet);
  70
  71       if D > (Duration'Last / Rate_Duration) then
  72          Ticks := Long_Long_Integer (int'Last);
  73       else
  74          Ticks_Duration := D * Rate_Duration;
  75          Ticks := Long_Long_Integer (Ticks_Duration);
  76
  77          if Ticks_Duration > Duration (Ticks) then
  78             Ticks := Ticks + 1;
  79          end if;
  80
  81          if Ticks > Long_Long_Integer (int'Last) then
  82             Ticks := Long_Long_Integer (int'Last);
  83          end if;
  84       end if;
  85
  86       return int (Ticks);
  87    end To_Clock_Ticks;
  88
  89    -----------
  90    -- Clock --
  91    -----------
  92
  93    function Clock return Duration is
  94       TS     : aliased timespec;
  95       Result : int;
  96    begin
  97       Result := clock_gettime (CLOCK_REALTIME, TS'Unchecked_Access);
  98       pragma Assert (Result = 0);
  99       return Duration (TS.ts_sec) + Duration (TS.ts_nsec) / 10#1#E9;
 100    end Clock;
 101
 102    ---------------------
 103    -- Monotonic_Clock --
 104    ---------------------
 105
 106    function Monotonic_Clock return Duration renames Clock;
 107
 108    -----------------
 109    -- Timed_Delay --
 110    -----------------
 111
 112    procedure Timed_Delay
 113      (Time : Duration;
 114       Mode : Integer)
 115    is
 116       Rel_Time   : Duration;
 117       Abs_Time   : Duration;
 118       Base_Time  : constant Duration := Clock;
 119       Check_Time : Duration := Base_Time;
 120       Ticks      : int;
 121
 122       Result     : int;
 123       pragma Unreferenced (Result);
 124
 125    begin
 126       if Mode = Relative then
 127          Rel_Time := Time;
 128          Abs_Time := Time + Check_Time;
 129       else
 130          Rel_Time := Time - Check_Time;
 131          Abs_Time := Time;
 132       end if;
 133
 134       if Rel_Time > 0.0 then
 135          loop
 136             Ticks := To_Clock_Ticks (Rel_Time);
 137
 138             if Mode = Relative and then Ticks < int'Last then
 139                --  The first tick will delay anytime between 0 and
 140                --  1 / sysClkRateGet seconds, so we need to add one to
 141                --  be on the safe side.
 142
 143                Ticks := Ticks + 1;
 144             end if;
 145
 146             Result := taskDelay (Ticks);
 147             Check_Time := Clock;
 148
 149             exit when Abs_Time <= Check_Time or else Check_Time < Base_Time;
 150
 151             Rel_Time := Abs_Time - Check_Time;
 152          end loop;
 153       end if;
 154    end Timed_Delay;
 155
 156    ----------------
 157    -- Initialize --
 158    ----------------
 159
 160    procedure Initialize is
 161    begin
 162       null;
 163    end Initialize;
 164
 165 end System.OS_Primitives;