1 ------------------------------------------------------------------------------
3 -- GNU ADA RUN-TIME LIBRARY (GNARL) COMPONENTS --
5 -- S Y S T E M . T A S K _ P R I M I T I V E S . O P E R A T I O N S . --
12 -- Copyright (C) 1991-2003, Florida State University --
14 -- GNARL is free software; you can redistribute it and/or modify it under --
15 -- terms of the GNU General Public License as published by the Free Soft- --
16 -- ware Foundation; either version 2, or (at your option) any later ver- --
17 -- sion. GNARL is distributed in the hope that it will be useful, but WITH- --
18 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
19 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
20 -- for more details. You should have received a copy of the GNU General --
21 -- Public License distributed with GNARL; see file COPYING. If not, write --
22 -- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
23 -- MA 02111-1307, USA. --
25 -- As a special exception, if other files instantiate generics from this --
26 -- unit, or you link this unit with other files to produce an executable, --
27 -- this unit does not by itself cause the resulting executable to be --
28 -- covered by the GNU General Public License. This exception does not --
29 -- however invalidate any other reasons why the executable file might be --
30 -- covered by the GNU Public License. --
32 -- GNARL was developed by the GNARL team at Florida State University. It is --
33 -- now maintained by Ada Core Technologies Inc. in cooperation with Florida --
34 -- State University (http://www.gnat.com). --
36 ------------------------------------------------------------------------------
38 -- This is a RTEMS version of this package which uses a special
39 -- variable for Ada self which is contexted switch implicitly by RTEMS.
41 -- This is the same as the POSIX version except that an RTEMS variable
42 -- is used instead of a POSIX key.
44 separate (System
.Task_Primitives
.Operations
)
45 package body Specific
is
47 -- The following gives the Ada run-time direct access to a variable
48 -- context switched by RTEMS at the lowest level.
50 RTEMS_Ada_Self
: System
.Address
;
51 pragma Import
(C
, RTEMS_Ada_Self
, "rtems_ada_self");
57 procedure Initialize
(Environment_Task
: Task_ID
) is
58 pragma Warnings
(Off
, Environment_Task
);
59 Result
: Interfaces
.C
.int
;
62 RTEMS_Ada_Self
:= To_Address
(Environment_Task
);
69 function Is_Valid_Task
return Boolean is
71 return RTEMS_Ada_Self
/= System
.Null_Address
;
78 procedure Set
(Self_Id
: Task_ID
) is
79 Result
: Interfaces
.C
.int
;
81 RTEMS_Ada_Self
:= To_Address
(Self_Id
);
88 -- To make Ada tasks and C threads interoperate better, we have added some
89 -- functionality to Self. Suppose a C main program (with threads) calls an
90 -- Ada procedure and the Ada procedure calls the tasking runtime system.
91 -- Eventually, a call will be made to self. Since the call is not coming
92 -- from an Ada task, there will be no corresponding ATCB.
94 -- What we do in Self is to catch references that do not come from
95 -- recognized Ada tasks, and create an ATCB for the calling thread.
97 -- The new ATCB will be "detached" from the normal Ada task master
98 -- hierarchy, much like the existing implicitly created signal-server
101 function Self
return Task_ID
is
102 Result
: System
.Address
;
105 Result
:= RTEMS_Ada_Self
;
107 -- If the key value is Null, then it is a non-Ada task.
109 if Result
/= System
.Null_Address
then
110 return To_Task_Id
(Result
);
112 return Register_Foreign_Thread
;