1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
5 -- S Y S T E M . P A R A M E T E R S --
11 -- Copyright (C) 1992-2000 Free Software Foundation, Inc. --
13 -- GNAT is free software; you can redistribute it and/or modify it under --
14 -- terms of the GNU General Public License as published by the Free Soft- --
15 -- ware Foundation; either version 2, or (at your option) any later ver- --
16 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
17 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
18 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
19 -- for more details. You should have received a copy of the GNU General --
20 -- Public License distributed with GNAT; see file COPYING. If not, write --
21 -- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
22 -- MA 02111-1307, USA. --
24 -- As a special exception, if other files instantiate generics from this --
25 -- unit, or you link this unit with other files to produce an executable, --
26 -- this unit does not by itself cause the resulting executable to be --
27 -- covered by the GNU General Public License. This exception does not --
28 -- however invalidate any other reasons why the executable file might be --
29 -- covered by the GNU Public License. --
31 -- GNAT was originally developed by the GNAT team at New York University. --
32 -- It is now maintained by Ada Core Technologies Inc (http://www.gnat.com). --
34 ------------------------------------------------------------------------------
36 -- This is the VxWorks/68k version of this package
38 -- This package defines some system dependent parameters for GNAT. These
39 -- are values that are referenced by the runtime library and are therefore
40 -- relevant to the target machine.
42 -- The parameters whose value is defined in the spec are not generally
43 -- expected to be changed. If they are changed, it will be necessary to
44 -- recompile the run-time library.
46 -- The parameters which are defined by functions can be changed by modifying
47 -- the body of System.Parameters in file s-parame.adb. A change to this body
48 -- requires only rebinding and relinking of the application.
50 -- Note: do not introduce any pragma Inline statements into this unit, since
51 -- otherwise the relinking and rebinding capability would be deactivated.
53 package System.Parameters is
54 pragma Pure (Parameters);
56 ---------------------------------------
57 -- Task And Stack Allocation Control --
58 ---------------------------------------
60 type Task_Storage_Size is new Integer;
61 -- Type used in tasking units for task storage size
63 type Size_Type is new Task_Storage_Size;
64 -- Type used to provide task storage size to runtime
66 Unspecified_Size : constant Size_Type := Size_Type'First;
67 -- Value used to indicate that no size type is set
69 subtype Ratio is Size_Type range -1 .. 100;
70 Dynamic : constant Size_Type := -1;
71 -- Secondary_Stack_Ratio is a constant between 0 and 100 wich
72 -- determines the percentage of the allocate task stack that is
73 -- used by the secondary stack (the rest being the primary stack).
74 -- The special value of minus one indicates that the secondary
75 -- stack is to be allocated from the heap instead.
77 Sec_Stack_Ratio : constant Ratio := -1;
78 -- This constant defines the handling of the secondary stack
80 Sec_Stack_Dynamic : constant Boolean := Sec_Stack_Ratio = Dynamic;
81 -- Convenient Boolean for testing for dynmaic secondary stack
83 function Default_Stack_Size return Size_Type;
84 -- Default task stack size used if none is specified
86 function Minimum_Stack_Size return Size_Type;
87 -- Minimum task stack size permitted
89 function Adjust_Storage_Size (Size : Size_Type) return Size_Type;
90 -- Given the storage size stored in the TCB, return the Storage_Size
91 -- value required by the RM for the Storage_Size attribute. The
92 -- required adjustment is as follows:
94 -- when Size = Unspecified_Size, return Default_Stack_Size
95 -- when Size < Minimum_Stack_Size, return Minimum_Stack_Size
96 -- otherwise return given Size
98 Stack_Grows_Down : constant Boolean := True;
99 -- This constant indicates whether the stack grows up (False) or
100 -- down (True) in memory as functions are called. It is used for
101 -- proper implementation of the stack overflow check.
103 ----------------------------------------------
104 -- Characteristics of types in Interfaces.C --
105 ----------------------------------------------
107 long_bits : constant := Long_Integer'Size;
108 -- Number of bits in type long and unsigned_long. The normal convention
109 -- is that this is the same as type Long_Integer, but this is not true
110 -- of all targets. For example, in OpenVMS long /= Long_Integer.
112 ----------------------------------------------
113 -- Behavior of Pragma Finalize_Storage_Only --
114 ----------------------------------------------
116 -- Garbage_Collected is a Boolean constant whose value indicates the
117 -- effect of the pragma Finalize_Storage_Entry on a controlled type.
119 -- Garbage_Collected = False
121 -- The system releases all storage on program termination only,
122 -- but not other garbage collection occurs, so finalization calls
123 -- are ommitted only for outer level onjects can be omitted if
124 -- pragma Finalize_Storage_Only is used.
126 -- Garbage_Collected = True
128 -- The system provides full garbage collection, so it is never
129 -- necessary to release storage for controlled objects for which
130 -- a pragma Finalize_Storage_Only is used.
132 Garbage_Collected : constant Boolean := False;
133 -- The storage mode for this system (release on program exit)
135 end System.Parameters;