gcc/ada/a-caldel.adb

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                GNU ADA RUN-TIME LIBRARY (GNARL) COMPONENTS               --
   4 --                                                                          --
   5 --                   A D A . C A L E N D A R . D E L A Y S                  --
   6 --                                                                          --
   7 --                                  B o d y                                 --
   8 --                                                                          --
   9 --                                                                          --
  10 --             Copyright (C) 1991-2001 Florida State University             --
  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 with System.OS_Primitives;
  37 --  Used for Delay_Modes
  38 --           Max_Sensible_Delay
  39
  40 with System.Soft_Links;
  41 --  Used for Timed_Delay
  42
  43 with System.Traces;
  44 --  Used for Send_Trace_Info
  45
  46 with System.Parameters;
  47 --  used for Runtime_Traces
  48
  49 package body Ada.Calendar.Delays is
  50
  51    package OSP renames System.OS_Primitives;
  52    package SSL renames System.Soft_Links;
  53
  54    use type SSL.Timed_Delay_Call;
  55
  56    use System.Traces;
  57
  58    --  Earlier, the following operations were implemented using
  59    --  System.Time_Operations.  The idea was to avoid sucking in the tasking
  60    --  packages.  This did not work.  Logically, we can't have it both ways.
  61    --  There is no way to implement time delays that will have correct task
  62    --  semantics without reference to the tasking run-time system.
  63    --  To achieve this goal, we now use soft links.
  64
  65    -----------------------
  66    -- Local Subprograms --
  67    -----------------------
  68
  69    procedure Timed_Delay_NT (Time : Duration; Mode : Integer);
  70    --  Timed delay procedure used when no tasking is active
  71
  72    ---------------
  73    -- Delay_For --
  74    ---------------
  75
  76    procedure Delay_For (D : Duration) is
  77    begin
  78       if System.Parameters.Runtime_Traces then
  79          Send_Trace_Info (W_Delay, D);
  80       end if;
  81
  82       SSL.Timed_Delay.all (Duration'Min (D, OSP.Max_Sensible_Delay),
  83                            OSP.Relative);
  84
  85       if System.Parameters.Runtime_Traces then
  86          Send_Trace_Info (M_Delay, D);
  87       end if;
  88    end Delay_For;
  89
  90    -----------------
  91    -- Delay_Until --
  92    -----------------
  93
  94    procedure Delay_Until (T : Time) is
  95       D : constant Duration := To_Duration (T);
  96
  97    begin
  98       if System.Parameters.Runtime_Traces then
  99          Send_Trace_Info (WU_Delay, D);
 100       end if;
 101
 102       SSL.Timed_Delay.all (D, OSP.Absolute_Calendar);
 103
 104       if System.Parameters.Runtime_Traces then
 105          Send_Trace_Info (M_Delay, D);
 106       end if;
 107    end Delay_Until;
 108
 109    --------------------
 110    -- Timed_Delay_NT --
 111    --------------------
 112
 113    procedure Timed_Delay_NT (Time : Duration; Mode : Integer) is
 114    begin
 115       OSP.Timed_Delay (Time, Mode);
 116    end Timed_Delay_NT;
 117
 118    -----------------
 119    -- To_Duration --
 120    -----------------
 121
 122    function To_Duration (T : Time) return Duration is
 123    begin
 124       return Duration (T);
 125    end To_Duration;
 126
 127 begin
 128    --  Set up the Timed_Delay soft link to the non tasking version
 129    --  if it has not been already set.
 130
 131    --  If tasking is present, Timed_Delay has already set this soft
 132    --  link, or this will be overriden during the elaboration of
 133    --  System.Tasking.Initialization
 134
 135    if SSL.Timed_Delay = null then
 136       SSL.Timed_Delay := Timed_Delay_NT'Access;
 137    end if;
 138 end Ada.Calendar.Delays;