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) 1998-2011, 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
34with 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
40with System.OS_Constants;
41with Interfaces.C;
42
43package body System.OS_Primitives is
44
45   use System.OS_Interface;
46   use type Interfaces.C.int;
47
48   package OSC renames System.OS_Constants;
49
50   ------------------------
51   -- Internal functions --
52   ------------------------
53
54   function To_Clock_Ticks (D : Duration) return int;
55   --  Convert a duration value (in seconds) into clock ticks.
56   --  Note that this routine is duplicated from System.OS_Interface since
57   --  as explained above, we do not want to depend on libgnarl
58
59   function To_Clock_Ticks (D : Duration) return int is
60      Ticks          : Long_Long_Integer;
61      Rate_Duration  : Duration;
62      Ticks_Duration : Duration;
63
64   begin
65      if D < 0.0 then
66         return -1;
67      end if;
68
69      --  Ensure that the duration can be converted to ticks
70      --  at the current clock tick rate without overflowing.
71
72      Rate_Duration := Duration (sysClkRateGet);
73
74      if D > (Duration'Last / Rate_Duration) then
75         Ticks := Long_Long_Integer (int'Last);
76      else
77         Ticks_Duration := D * Rate_Duration;
78         Ticks := Long_Long_Integer (Ticks_Duration);
79
80         if Ticks_Duration > Duration (Ticks) then
81            Ticks := Ticks + 1;
82         end if;
83
84         if Ticks > Long_Long_Integer (int'Last) then
85            Ticks := Long_Long_Integer (int'Last);
86         end if;
87      end if;
88
89      return int (Ticks);
90   end To_Clock_Ticks;
91
92   -----------
93   -- Clock --
94   -----------
95
96   function Clock return Duration is
97      TS     : aliased timespec;
98      Result : int;
99   begin
100      Result := clock_gettime (OSC.CLOCK_RT_Ada, 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      Rel_Time   : Duration;
120      Abs_Time   : Duration;
121      Base_Time  : constant Duration := Clock;
122      Check_Time : Duration := Base_Time;
123      Ticks      : int;
124
125      Result     : int;
126      pragma Unreferenced (Result);
127
128   begin
129      if Mode = Relative then
130         Rel_Time := Time;
131         Abs_Time := Time + Check_Time;
132      else
133         Rel_Time := Time - Check_Time;
134         Abs_Time := Time;
135      end if;
136
137      if Rel_Time > 0.0 then
138         loop
139            Ticks := To_Clock_Ticks (Rel_Time);
140
141            if Mode = Relative and then Ticks < int'Last then
142               --  The first tick will delay anytime between 0 and
143               --  1 / sysClkRateGet seconds, so we need to add one to
144               --  be on the safe side.
145
146               Ticks := Ticks + 1;
147            end if;
148
149            Result := taskDelay (Ticks);
150            Check_Time := Clock;
151
152            exit when Abs_Time <= Check_Time or else Check_Time < Base_Time;
153
154            Rel_Time := Abs_Time - Check_Time;
155         end loop;
156      end if;
157   end Timed_Delay;
158
159   ----------------
160   -- Initialize --
161   ----------------
162
163   procedure Initialize is
164   begin
165      null;
166   end Initialize;
167
168end System.OS_Primitives;
169