Implement -mmemcpy-strategy= and -mmemset-strategy= options
[official-gcc.git] / gcc / ada / s-parame-vxworks.ads
blob748e7d81b39cab22382adb1e5ff04cb311e5312a
1 ------------------------------------------------------------------------------
2 -- --
3 -- GNAT COMPILER COMPONENTS --
4 -- --
5 -- S Y S T E M . P A R A M E T E R S --
6 -- --
7 -- S p e c --
8 -- --
9 -- Copyright (C) 1992-2011, Free Software Foundation, Inc. --
10 -- --
11 -- GNAT 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 -- GNAT was originally developed by the GNAT team at New York University. --
28 -- Extensive contributions were provided by Ada Core Technologies Inc. --
29 -- --
30 ------------------------------------------------------------------------------
32 -- This is the default VxWorks version of the package
34 -- This package defines some system dependent parameters for GNAT. These
35 -- are values that are referenced by the runtime library and are therefore
36 -- relevant to the target machine.
38 -- The parameters whose value is defined in the spec are not generally
39 -- expected to be changed. If they are changed, it will be necessary to
40 -- recompile the run-time library.
42 -- The parameters which are defined by functions can be changed by modifying
43 -- the body of System.Parameters in file s-parame.adb. A change to this body
44 -- requires only rebinding and relinking of the application.
46 -- Note: do not introduce any pragma Inline statements into this unit, since
47 -- otherwise the relinking and rebinding capability would be deactivated.
49 package System.Parameters is
50 pragma Pure;
52 ---------------------------------------
53 -- Task And Stack Allocation Control --
54 ---------------------------------------
56 type Task_Storage_Size is new Integer;
57 -- Type used in tasking units for task storage size
59 type Size_Type is new Task_Storage_Size;
60 -- Type used to provide task storage size to runtime
62 Unspecified_Size : constant Size_Type := Size_Type'First;
63 -- Value used to indicate that no size type is set
65 subtype Percentage is Size_Type range -1 .. 100;
66 Dynamic : constant Size_Type := -1;
67 -- The secondary stack ratio is a constant between 0 and 100 which
68 -- determines the percentage of the allocated task stack that is
69 -- used by the secondary stack (the rest being the primary stack).
70 -- The special value of minus one indicates that the secondary
71 -- stack is to be allocated from the heap instead.
73 Sec_Stack_Percentage : constant Percentage := Dynamic;
74 -- This constant defines the handling of the secondary stack
76 Sec_Stack_Dynamic : constant Boolean := Sec_Stack_Percentage = Dynamic;
77 -- Convenient Boolean for testing for dynamic secondary stack
79 function Default_Stack_Size return Size_Type;
80 -- Default task stack size used if none is specified
82 function Minimum_Stack_Size return Size_Type;
83 -- Minimum task stack size permitted
85 function Adjust_Storage_Size (Size : Size_Type) return Size_Type;
86 -- Given the storage size stored in the TCB, return the Storage_Size
87 -- value required by the RM for the Storage_Size attribute. The
88 -- required adjustment is as follows:
90 -- when Size = Unspecified_Size, return Default_Stack_Size
91 -- when Size < Minimum_Stack_Size, return Minimum_Stack_Size
92 -- otherwise return given Size
94 Default_Env_Stack_Size : constant Size_Type := 14_336;
95 -- Assumed size of the environment task, if no other information
96 -- is available. This value is used when stack checking is
97 -- enabled and no GNAT_STACK_LIMIT environment variable is set.
98 -- This value is chosen as the VxWorks default stack size is 20kB,
99 -- and a little more than 4kB is necessary for the run time.
101 Stack_Grows_Down : constant Boolean := True;
102 -- This constant indicates whether the stack grows up (False) or
103 -- down (True) in memory as functions are called. It is used for
104 -- proper implementation of the stack overflow check.
106 ----------------------------------------------
107 -- Characteristics of types in Interfaces.C --
108 ----------------------------------------------
110 long_bits : constant := Long_Integer'Size;
111 -- Number of bits in type long and unsigned_long. The normal convention
112 -- is that this is the same as type Long_Integer, but this is not true
113 -- of all targets. For example, in OpenVMS long /= Long_Integer.
115 ptr_bits : constant := Standard'Address_Size;
116 subtype C_Address is System.Address;
117 -- Number of bits in Interfaces.C pointers, normally a standard address,
118 -- except on 64-bit VMS where they are 32-bit addresses, for compatibility
119 -- with legacy code.
121 C_Malloc_Linkname : constant String := "__gnat_malloc";
122 -- Name of runtime function used to allocate such a pointer
124 ----------------------------------------------
125 -- Behavior of Pragma Finalize_Storage_Only --
126 ----------------------------------------------
128 -- Garbage_Collected is a Boolean constant whose value indicates the
129 -- effect of the pragma Finalize_Storage_Entry on a controlled type.
131 -- Garbage_Collected = False
133 -- The system releases all storage on program termination only,
134 -- but not other garbage collection occurs, so finalization calls
135 -- are omitted only for outer level objects can be omitted if
136 -- pragma Finalize_Storage_Only is used.
138 -- Garbage_Collected = True
140 -- The system provides full garbage collection, so it is never
141 -- necessary to release storage for controlled objects for which
142 -- a pragma Finalize_Storage_Only is used.
144 Garbage_Collected : constant Boolean := False;
145 -- The storage mode for this system (release on program exit)
147 ---------------------
148 -- Tasking Profile --
149 ---------------------
151 -- In the following sections, constant parameters are defined to
152 -- allow some optimizations and fine tuning within the tasking run time
153 -- based on restrictions on the tasking features.
155 ----------------------
156 -- Locking Strategy --
157 ----------------------
159 Single_Lock : constant Boolean := False;
160 -- Indicates whether a single lock should be used within the tasking
161 -- run-time to protect internal structures. If True, a single lock
162 -- will be used, meaning less locking/unlocking operations, but also
163 -- more global contention. In general, Single_Lock should be set to
164 -- True on single processor machines, and to False to multi-processor
165 -- systems, but this can vary from application to application and also
166 -- depends on the scheduling policy.
168 -------------------
169 -- Task Abortion --
170 -------------------
172 No_Abort : constant Boolean := False;
173 -- This constant indicates whether abort statements and asynchronous
174 -- transfer of control (ATC) are disallowed. If set to True, it is
175 -- assumed that neither construct is used, and the run time does not
176 -- need to defer/undefer abort and check for pending actions at
177 -- completion points. A value of True for No_Abort corresponds to:
178 -- pragma Restrictions (No_Abort_Statements);
179 -- pragma Restrictions (Max_Asynchronous_Select_Nesting => 0);
181 ---------------------
182 -- Task Attributes --
183 ---------------------
185 Default_Attribute_Count : constant := 4;
186 -- Number of pre-allocated Address-sized task attributes stored in the
187 -- task control block.
189 --------------------
190 -- Runtime Traces --
191 --------------------
193 Runtime_Traces : constant Boolean := False;
194 -- This constant indicates whether the runtime outputs traces to a
195 -- predefined output or not (True means that traces are output).
196 -- See System.Traces for more details.
198 -----------------------
199 -- Task Image Length --
200 -----------------------
202 Max_Task_Image_Length : constant := 32;
203 -- This constant specifies the maximum length of a task's image
205 ------------------------------
206 -- Exception Message Length --
207 ------------------------------
209 Default_Exception_Msg_Max_Length : constant := 200;
210 -- This constant specifies the default number of characters to allow
211 -- in an exception message (200 is minimum required by RM 11.4.1(18)).
213 end System.Parameters;