gcc/ada/5zosprim.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 --                                                                          --
  10 --          Copyright (C) 1998-2001 Free Software Foundation, Inc.          --
  11 --                                                                          --
  12 -- GNARL is free software; you can  redistribute it  and/or modify it under --
  13 -- terms of the  GNU General Public License as published  by the Free Soft- --
  14 -- ware  Foundation;  either version 2,  or (at your option) any later ver- --
  15 -- sion. GNARL is distributed in the hope that it will be useful, but WITH- --
  16 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  17 -- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
  18 -- for  more details.  You should have  received  a copy of the GNU General --
  19 -- Public License  distributed with GNARL; see file COPYING.  If not, write --
  20 -- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
  21 -- MA 02111-1307, USA.                                                      --
  22 --                                                                          --
  23 -- As a special exception,  if other files  instantiate  generics from this --
  24 -- unit, or you link  this unit with other files  to produce an executable, --
  25 -- this  unit  does not  by itself cause  the resulting  executable  to  be --
  26 -- covered  by the  GNU  General  Public  License.  This exception does not --
  27 -- however invalidate  any other reasons why  the executable file  might be --
  28 -- covered by the  GNU Public License.                                      --
  29 --                                                                          --
  30 -- GNARL was developed by the GNARL team at Florida State University. It is --
  31 -- now maintained by Ada Core Technologies Inc. in cooperation with Florida --
  32 -- State University (http://www.gnat.com).                                  --
  33 --                                                                          --
  34 ------------------------------------------------------------------------------
  35
  36 --  This version is for VxWorks targets
  37
  38 with System.OS_Interface;
  39 --  Since the thread library is part of the VxWorks kernel, using OS_Interface
  40 --  is not a problem here, as long as we only use System.OS_Interface as a
  41 --  set of C imported routines: using Ada routines from this package would
  42 --  create a dependency on libgnarl in libgnat, which is not desirable.
  43
  44 with Interfaces.C;
  45 --  used for type int
  46
  47 package body System.OS_Primitives is
  48
  49    use System.OS_Interface;
  50
  51    --------------------------
  52    --  Internal functions  --
  53    --------------------------
  54
  55    function To_Clock_Ticks (D : Duration) return int;
  56    --  Convert a duration value (in seconds) into clock ticks.
  57    --  Note that this routine is duplicated from System.OS_Interface since
  58    --  as explained above, we do not want to depend on libgnarl
  59
  60    function To_Clock_Ticks (D : Duration) return int is
  61       Ticks          : Long_Long_Integer;
  62       Rate_Duration  : Duration;
  63       Ticks_Duration : Duration;
  64    begin
  65       --  Ensure that the duration can be converted to ticks
  66       --  at the current clock tick rate without overflowing.
  67
  68       Rate_Duration := Duration (sysClkRateGet);
  69
  70       if D > (Duration'Last / Rate_Duration) then
  71          Ticks := Long_Long_Integer (int'Last);
  72       else
  73          --  We always want to round up to the nearest clock tick.
  74
  75          Ticks_Duration := D * Rate_Duration;
  76          Ticks := Long_Long_Integer (Ticks_Duration);
  77
  78          if Ticks_Duration > Duration (Ticks) then
  79             Ticks := Ticks + 1;
  80          end if;
  81
  82          if Ticks > Long_Long_Integer (int'Last) then
  83             Ticks := Long_Long_Integer (int'Last);
  84          end if;
  85       end if;
  86
  87       return int (Ticks);
  88    end To_Clock_Ticks;
  89
  90    -----------
  91    -- Clock --
  92    -----------
  93
  94    function Clock return Duration is
  95       TS     : aliased timespec;
  96       Result : int;
  97
  98       use type Interfaces.C.int;
  99    begin
 100       Result := clock_gettime (CLOCK_REALTIME, TS'Unchecked_Access);
 101       pragma Assert (Result = 0);
 102       return Duration (TS.ts_sec) + Duration (TS.ts_nsec) / 10#1#E9;
 103    end Clock;
 104
 105    ---------------------
 106    -- Monotonic_Clock --
 107    ---------------------
 108
 109    function Monotonic_Clock return Duration renames Clock;
 110
 111    -----------------
 112    -- Timed_Delay --
 113    -----------------
 114
 115    procedure Timed_Delay
 116      (Time : Duration;
 117       Mode : Integer)
 118    is
 119       Result     : int;
 120       Rel_Time   : Duration;
 121       Abs_Time   : Duration;
 122       Check_Time : Duration := Clock;
 123
 124    begin
 125       if Mode = Relative then
 126          Rel_Time := Time;
 127          Abs_Time := Time + Check_Time;
 128       else
 129          Rel_Time := Time - Check_Time;
 130          Abs_Time := Time;
 131       end if;
 132
 133       if Rel_Time > 0.0 then
 134          loop
 135             Result := taskDelay (To_Clock_Ticks (Rel_Time));
 136             Check_Time := Clock;
 137
 138             exit when Abs_Time <= Check_Time;
 139
 140             Rel_Time := Abs_Time - Check_Time;
 141          end loop;
 142       end if;
 143    end Timed_Delay;
 144
 145 end System.OS_Primitives;