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) 1998-2012, 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 is the OpenVMS/Alpha version of this file
33
34with System.Aux_DEC;
35
36package body System.OS_Primitives is
37
38   --------------------------------------
39   -- Local functions and declarations --
40   --------------------------------------
41
42   function Get_GMToff return Integer;
43   pragma Import (C, Get_GMToff, "get_gmtoff");
44   --  Get the offset from GMT for this timezone
45
46   function VMS_Epoch_Offset return Long_Integer;
47   pragma Inline (VMS_Epoch_Offset);
48   --  The offset between the Unix Epoch and the VMS Epoch
49
50   subtype Cond_Value_Type is System.Aux_DEC.Unsigned_Longword;
51   --  Condition Value return type
52
53   ----------------------
54   -- VMS_Epoch_Offset --
55   ----------------------
56
57   function VMS_Epoch_Offset return Long_Integer is
58   begin
59      return 10_000_000 * (3_506_716_800 + Long_Integer (Get_GMToff));
60   end VMS_Epoch_Offset;
61
62   ----------------
63   -- Sys_Schdwk --
64   ----------------
65   --
66   --  Schedule Wakeup
67   --
68   --  status = returned status
69   --  pidadr = address of process id to be woken up
70   --  prcnam = name of process to be woken up
71   --  daytim = time to wake up
72   --  reptim = repetition interval of wakeup calls
73   --
74
75   procedure Sys_Schdwk
76     (
77      Status : out Cond_Value_Type;
78      Pidadr : Address := Null_Address;
79      Prcnam : String := String'Null_Parameter;
80      Daytim : Long_Integer;
81      Reptim : Long_Integer := Long_Integer'Null_Parameter
82     );
83
84   pragma Import (External, Sys_Schdwk);
85   --  VMS system call to schedule a wakeup event
86   pragma Import_Valued_Procedure
87     (Sys_Schdwk, "SYS$SCHDWK",
88      (Cond_Value_Type, Address, String,         Long_Integer, Long_Integer),
89      (Value,           Value,   Descriptor (S), Reference,    Reference)
90     );
91
92   ----------------
93   -- Sys_Gettim --
94   ----------------
95   --
96   --  Get System Time
97   --
98   --  status = returned status
99   --  tim    = current system time
100   --
101
102   procedure Sys_Gettim
103     (
104      Status : out Cond_Value_Type;
105      Tim    : out OS_Time
106     );
107   --  VMS system call to get the current system time
108   pragma Import (External, Sys_Gettim);
109   pragma Import_Valued_Procedure
110     (Sys_Gettim, "SYS$GETTIM",
111      (Cond_Value_Type, OS_Time),
112      (Value,           Reference)
113     );
114
115   ---------------
116   -- Sys_Hiber --
117   ---------------
118
119   --  Hibernate (until woken up)
120
121   --  status = returned status
122
123   procedure Sys_Hiber (Status : out Cond_Value_Type);
124   --  VMS system call to hibernate the current process
125   pragma Import (External, Sys_Hiber);
126   pragma Import_Valued_Procedure
127     (Sys_Hiber, "SYS$HIBER",
128      (Cond_Value_Type),
129      (Value)
130     );
131
132   -----------
133   -- Clock --
134   -----------
135
136   function OS_Clock return OS_Time is
137      Status : Cond_Value_Type;
138      T      : OS_Time;
139   begin
140      Sys_Gettim (Status, T);
141      return (T);
142   end OS_Clock;
143
144   -----------
145   -- Clock --
146   -----------
147
148   function Clock return Duration is
149   begin
150      return To_Duration (OS_Clock, Absolute_Calendar);
151   end Clock;
152
153   ----------------
154   -- Initialize --
155   ----------------
156
157   procedure Initialize is
158   begin
159      null;
160   end Initialize;
161
162   ---------------------
163   -- Monotonic_Clock --
164   ---------------------
165
166   function Monotonic_Clock return Duration renames Clock;
167
168   -----------------
169   -- Timed_Delay --
170   -----------------
171
172   procedure Timed_Delay
173     (Time : Duration;
174      Mode : Integer)
175   is
176      Sleep_Time : OS_Time;
177      Status     : Cond_Value_Type;
178      pragma Unreferenced (Status);
179
180   begin
181      Sleep_Time := To_OS_Time (Time, Mode);
182      Sys_Schdwk (Status => Status, Daytim => Sleep_Time);
183      Sys_Hiber (Status);
184   end Timed_Delay;
185
186   -----------------
187   -- To_Duration --
188   -----------------
189
190   function To_Duration (T : OS_Time; Mode : Integer) return Duration is
191      pragma Warnings (Off, Mode);
192   begin
193      return Duration'Fixed_Value (T - VMS_Epoch_Offset) * 100;
194   end To_Duration;
195
196   ----------------
197   -- To_OS_Time --
198   ----------------
199
200   function To_OS_Time (D : Duration; Mode : Integer) return OS_Time is
201   begin
202      if Mode = Relative then
203         return -(Long_Integer'Integer_Value (D) / 100);
204      else
205         return Long_Integer'Integer_Value (D) / 100 + VMS_Epoch_Offset;
206      end if;
207   end To_OS_Time;
208
209end System.OS_Primitives;
210