1 ------------------------------------------------------------------------------
3 -- GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS --
5 -- S Y S T E M . T A S K I N G --
9 -- Copyright (C) 1992-2006, Free Software Foundation, Inc. --
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 2, or (at your option) any later ver- --
14 -- sion. GNARL 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. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNARL; see file COPYING. If not, write --
19 -- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, --
20 -- Boston, MA 02110-1301, USA. --
22 -- As a special exception, if other files instantiate generics from this --
23 -- unit, or you link this unit with other files to produce an executable, --
24 -- this unit does not by itself cause the resulting executable to be --
25 -- covered by the GNU General Public License. This exception does not --
26 -- however invalidate any other reasons why the executable file might be --
27 -- covered by the GNU Public License. --
29 -- GNARL was developed by the GNARL team at Florida State University. --
30 -- Extensive contributions were provided by Ada Core Technologies, Inc. --
32 ------------------------------------------------------------------------------
35 -- Turn off polling, we do not want ATC polling to take place during
36 -- tasking operations. It causes infinite loops and other problems.
38 with System.Task_Primitives.Operations;
41 with System.Storage_Elements;
42 -- Needed for initializing Stack_Info.Size
44 package body System.Tasking is
46 package STPO renames System.Task_Primitives.Operations;
52 function Detect_Blocking return Boolean is
53 GL_Detect_Blocking : Integer;
54 pragma Import (C, GL_Detect_Blocking, "__gl_detect_blocking");
55 -- Global variable exported by the binder generated file.
56 -- A value equal to 1 indicates that pragma Detect_Blocking is active,
57 -- while 0 is used for the pragma not being present.
60 return GL_Detect_Blocking = 1;
67 function Self return Task_Id renames STPO.Self;
73 procedure Initialize_ATCB
75 Task_Entry_Point : Task_Procedure_Access;
76 Task_Arg : System.Address;
78 Elaborated : Access_Boolean;
79 Base_Priority : System.Any_Priority;
80 Task_Info : System.Task_Info.Task_Info_Type;
81 Stack_Size : System.Parameters.Size_Type;
83 Success : out Boolean) is
85 T.Common.State := Unactivated;
87 -- Initialize T.Common.LL
89 STPO.Initialize_TCB (T, Success);
95 T.Common.Parent := Parent;
96 T.Common.Base_Priority := Base_Priority;
97 T.Common.Current_Priority := 0;
98 T.Common.Protected_Action_Nesting := 0;
99 T.Common.Call := null;
100 T.Common.Task_Arg := Task_Arg;
101 T.Common.Task_Entry_Point := Task_Entry_Point;
102 T.Common.Activator := Self_ID;
103 T.Common.Wait_Count := 0;
104 T.Common.Elaborated := Elaborated;
105 T.Common.Activation_Failed := False;
106 T.Common.Task_Info := Task_Info;
107 T.Common.Global_Task_Lock_Nesting := 0;
108 T.Common.Fall_Back_Handler := null;
109 T.Common.Specific_Handler := null;
111 if T.Common.Parent = null then
112 -- For the environment task, the adjusted stack size is
113 -- meaningless. For example, an unspecified Stack_Size means
114 -- that the stack size is determined by the environment, or
115 -- can grow dynamically. The Stack_Checking algorithm
116 -- therefore needs to use the requested size, or 0 in
117 -- case of an unknown size.
119 T.Common.Compiler_Data.Pri_Stack_Info.Size :=
120 Storage_Elements.Storage_Offset (Stack_Size);
123 T.Common.Compiler_Data.Pri_Stack_Info.Size :=
124 Storage_Elements.Storage_Offset
125 (Parameters.Adjust_Storage_Size (Stack_Size));
128 -- Link the task into the list of all tasks
130 T.Common.All_Tasks_Link := All_Tasks_List;
138 Main_Task_Image : constant String := "main_task";
139 -- Image of environment task
141 Main_Priority : Integer;
142 pragma Import (C, Main_Priority, "__gl_main_priority");
143 -- Priority for main task. Note that this is of type Integer, not
144 -- Priority, because we use the value -1 to indicate the default
145 -- main priority, and that is of course not in Priority'range.
147 Initialized : Boolean := False;
148 -- Used to prevent multiple calls to Initialize
150 procedure Initialize is
153 Base_Priority : Any_Priority;
162 -- Initialize Environment Task
164 if Main_Priority = Unspecified_Priority then
165 Base_Priority := Default_Priority;
167 Base_Priority := Priority (Main_Priority);
171 T := STPO.New_ATCB (0);
173 (null, null, Null_Address, Null_Task, null, Base_Priority,
174 Task_Info.Unspecified_Task_Info, 0, T, Success);
175 pragma Assert (Success);
178 STPO.Set_Priority (T, T.Common.Base_Priority);
179 T.Common.State := Runnable;
180 T.Common.Task_Image_Len := Main_Task_Image'Length;
181 T.Common.Task_Image (Main_Task_Image'Range) := Main_Task_Image;
183 -- Only initialize the first element since others are not relevant
184 -- in ravenscar mode. Rest of the initialization is done in Init_RTS.
186 T.Entry_Calls (1).Self := T;