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) 1992-2008, 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 tasking
36 -- operations. It causes infinite loops and other problems.
38 with System.Task_Primitives.Operations;
39 with System.Storage_Elements;
41 package body System.Tasking is
43 package STPO renames System.Task_Primitives.Operations;
49 function Detect_Blocking return Boolean is
50 GL_Detect_Blocking : Integer;
51 pragma Import (C, GL_Detect_Blocking, "__gl_detect_blocking");
52 -- Global variable exported by the binder generated file.
53 -- A value equal to 1 indicates that pragma Detect_Blocking is active,
54 -- while 0 is used for the pragma not being present.
57 return GL_Detect_Blocking = 1;
64 function Self return Task_Id renames STPO.Self;
70 function Storage_Size (T : Task_Id) return System.Parameters.Size_Type is
73 System.Parameters.Size_Type
74 (T.Common.Compiler_Data.Pri_Stack_Info.Size);
81 procedure Initialize_ATCB
83 Task_Entry_Point : Task_Procedure_Access;
84 Task_Arg : System.Address;
86 Elaborated : Access_Boolean;
87 Base_Priority : System.Any_Priority;
88 Task_Info : System.Task_Info.Task_Info_Type;
89 Stack_Size : System.Parameters.Size_Type;
91 Success : out Boolean) is
93 T.Common.State := Unactivated;
95 -- Initialize T.Common.LL
97 STPO.Initialize_TCB (T, Success);
103 T.Common.Parent := Parent;
104 T.Common.Base_Priority := Base_Priority;
105 T.Common.Current_Priority := 0;
106 T.Common.Protected_Action_Nesting := 0;
107 T.Common.Call := null;
108 T.Common.Task_Arg := Task_Arg;
109 T.Common.Task_Entry_Point := Task_Entry_Point;
110 T.Common.Activator := Self_ID;
111 T.Common.Wait_Count := 0;
112 T.Common.Elaborated := Elaborated;
113 T.Common.Activation_Failed := False;
114 T.Common.Task_Info := Task_Info;
115 T.Common.Global_Task_Lock_Nesting := 0;
116 T.Common.Fall_Back_Handler := null;
117 T.Common.Specific_Handler := null;
119 if T.Common.Parent = null then
120 -- For the environment task, the adjusted stack size is
121 -- meaningless. For example, an unspecified Stack_Size means
122 -- that the stack size is determined by the environment, or
123 -- can grow dynamically. The Stack_Checking algorithm
124 -- therefore needs to use the requested size, or 0 in
125 -- case of an unknown size.
127 T.Common.Compiler_Data.Pri_Stack_Info.Size :=
128 Storage_Elements.Storage_Offset (Stack_Size);
131 T.Common.Compiler_Data.Pri_Stack_Info.Size :=
132 Storage_Elements.Storage_Offset
133 (Parameters.Adjust_Storage_Size (Stack_Size));
136 -- Link the task into the list of all tasks
138 T.Common.All_Tasks_Link := All_Tasks_List;
146 Main_Task_Image : constant String := "main_task";
147 -- Image of environment task
149 Main_Priority : Integer;
150 pragma Import (C, Main_Priority, "__gl_main_priority");
151 -- Priority for main task. Note that this is of type Integer, not
152 -- Priority, because we use the value -1 to indicate the default
153 -- main priority, and that is of course not in Priority'range.
155 Initialized : Boolean := False;
156 -- Used to prevent multiple calls to Initialize
158 procedure Initialize is
160 Base_Priority : Any_Priority;
163 pragma Warnings (Off, Success);
172 -- Initialize Environment Task
174 if Main_Priority = Unspecified_Priority then
175 Base_Priority := Default_Priority;
177 Base_Priority := Priority (Main_Priority);
181 T := STPO.New_ATCB (0);
183 (null, null, Null_Address, Null_Task, null, Base_Priority,
184 Task_Info.Unspecified_Task_Info, 0, T, Success);
185 pragma Assert (Success);
188 STPO.Set_Priority (T, T.Common.Base_Priority);
189 T.Common.State := Runnable;
190 T.Common.Task_Image_Len := Main_Task_Image'Length;
191 T.Common.Task_Image (Main_Task_Image'Range) := Main_Task_Image;
193 -- Only initialize the first element since others are not relevant
194 -- in ravenscar mode. Rest of the initialization is done in Init_RTS.
196 T.Entry_Calls (1).Self := T;