+++ /dev/null
-------------------------------------------------------------------------------
--- --
--- GNAT COMPILER COMPONENTS --
--- --
--- S Y S T E M . P A R A M E T E R S --
--- --
--- S p e c --
--- --
--- Copyright (C) 1992-2016, Free Software Foundation, Inc. --
--- --
--- GNAT is free software; you can redistribute it and/or modify it under --
--- terms of the GNU General Public License as published by the Free Soft- --
--- ware Foundation; either version 3, or (at your option) any later ver- --
--- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
--- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
--- or FITNESS FOR A PARTICULAR PURPOSE. --
--- --
--- As a special exception under Section 7 of GPL version 3, you are granted --
--- additional permissions described in the GCC Runtime Library Exception, --
--- version 3.1, as published by the Free Software Foundation. --
--- --
--- You should have received a copy of the GNU General Public License and --
--- a copy of the GCC Runtime Library Exception along with this program; --
--- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
--- <http://www.gnu.org/licenses/>. --
--- --
--- GNAT was originally developed by the GNAT team at New York University. --
--- Extensive contributions were provided by Ada Core Technologies Inc. --
--- --
-------------------------------------------------------------------------------
-
--- Version is used by VxWorks 653, VxWorks MILS, and VxWorks6 cert Ravenscar
-
--- This package defines some system dependent parameters for GNAT. These
--- are values that are referenced by the runtime library and are therefore
--- relevant to the target machine.
-
--- The parameters whose value is defined in the spec are not generally
--- expected to be changed. If they are changed, it will be necessary to
--- recompile the run-time library.
-
--- The parameters which are defined by functions can be changed by modifying
--- the body of System.Parameters in file s-parame.adb. A change to this body
--- requires only rebinding and relinking of the application.
-
--- Note: do not introduce any pragma Inline statements into this unit, since
--- otherwise the relinking and rebinding capability would be deactivated.
-
-package System.Parameters is
- pragma Pure;
-
- ---------------------------------------
- -- Task And Stack Allocation Control --
- ---------------------------------------
-
- type Task_Storage_Size is new Integer;
- -- Type used in tasking units for task storage size
-
- type Size_Type is new Task_Storage_Size;
- -- Type used to provide task storage size to runtime
-
- Unspecified_Size : constant Size_Type := Size_Type'First;
- -- Value used to indicate that no size type is set
-
- subtype Percentage is Size_Type range -1 .. 100;
- Dynamic : constant Size_Type := -1;
- -- The secondary stack ratio is a constant between 0 and 100 which
- -- determines the percentage of the allocated task stack that is
- -- used by the secondary stack (the rest being the primary stack).
- -- The special value of minus one indicates that the secondary
- -- stack is to be allocated from the heap instead.
-
- Sec_Stack_Percentage : constant Percentage := 25;
- -- This constant defines the handling of the secondary stack
-
- Sec_Stack_Dynamic : constant Boolean := Sec_Stack_Percentage = Dynamic;
- -- Convenient Boolean for testing for dynamic secondary stack
-
- function Default_Stack_Size return Size_Type;
- -- Default task stack size used if none is specified
-
- function Minimum_Stack_Size return Size_Type;
- -- Minimum task stack size permitted
-
- function Adjust_Storage_Size (Size : Size_Type) return Size_Type;
- -- Given the storage size stored in the TCB, return the Storage_Size
- -- value required by the RM for the Storage_Size attribute. The
- -- required adjustment is as follows:
- --
- -- when Size = Unspecified_Size, return Default_Stack_Size
- -- when Size < Minimum_Stack_Size, return Minimum_Stack_Size
- -- otherwise return given Size
-
- Default_Env_Stack_Size : constant Size_Type := 14_336;
- -- Assumed size of the environment task, if no other information
- -- is available. This value is used when stack checking is
- -- enabled and no GNAT_STACK_LIMIT environment variable is set.
- -- This value is chosen as the VxWorks default stack size is 20kB,
- -- and a little more than 4kB is necessary for the run time.
-
- Stack_Grows_Down : constant Boolean := True;
- -- This constant indicates whether the stack grows up (False) or
- -- down (True) in memory as functions are called. It is used for
- -- proper implementation of the stack overflow check.
-
- ----------------------------------------------
- -- Characteristics of types in Interfaces.C --
- ----------------------------------------------
-
- long_bits : constant := Long_Integer'Size;
- -- Number of bits in type long and unsigned_long. The normal convention
- -- is that this is the same as type Long_Integer, but this may not be true
- -- of all targets.
-
- ptr_bits : constant := Standard'Address_Size;
- subtype C_Address is System.Address;
- -- Number of bits in Interfaces.C pointers, normally a standard address
-
- C_Malloc_Linkname : constant String := "__gnat_malloc";
- -- Name of runtime function used to allocate such a pointer
-
- ----------------------------------------------
- -- Behavior of Pragma Finalize_Storage_Only --
- ----------------------------------------------
-
- -- Garbage_Collected is a Boolean constant whose value indicates the
- -- effect of the pragma Finalize_Storage_Entry on a controlled type.
-
- -- Garbage_Collected = False
-
- -- The system releases all storage on program termination only,
- -- but not other garbage collection occurs, so finalization calls
- -- are omitted only for outer level objects can be omitted if
- -- pragma Finalize_Storage_Only is used.
-
- -- Garbage_Collected = True
-
- -- The system provides full garbage collection, so it is never
- -- necessary to release storage for controlled objects for which
- -- a pragma Finalize_Storage_Only is used.
-
- Garbage_Collected : constant Boolean := False;
- -- The storage mode for this system (release on program exit)
-
- ---------------------
- -- Tasking Profile --
- ---------------------
-
- -- In the following sections, constant parameters are defined to
- -- allow some optimizations and fine tuning within the tasking run time
- -- based on restrictions on the tasking features.
-
- ----------------------
- -- Locking Strategy --
- ----------------------
-
- Single_Lock : constant Boolean := False;
- -- Indicates whether a single lock should be used within the tasking
- -- run-time to protect internal structures. If True, a single lock
- -- will be used, meaning less locking/unlocking operations, but also
- -- more global contention. In general, Single_Lock should be set to
- -- True on single processor machines, and to False to multi-processor
- -- systems, but this can vary from application to application and also
- -- depends on the scheduling policy.
-
- -------------------
- -- Task Abortion --
- -------------------
-
- No_Abort : constant Boolean := False;
- -- This constant indicates whether abort statements and asynchronous
- -- transfer of control (ATC) are disallowed. If set to True, it is
- -- assumed that neither construct is used, and the run time does not
- -- need to defer/undefer abort and check for pending actions at
- -- completion points. A value of True for No_Abort corresponds to:
- -- pragma Restrictions (No_Abort_Statements);
- -- pragma Restrictions (Max_Asynchronous_Select_Nesting => 0);
-
- ---------------------
- -- Task Attributes --
- ---------------------
-
- Max_Attribute_Count : constant := 8;
- -- Number of task attributes stored in the task control block
-
- --------------------
- -- Runtime Traces --
- --------------------
-
- Runtime_Traces : constant Boolean := False;
- -- This constant indicates whether the runtime outputs traces to a
- -- predefined output or not (True means that traces are output).
- -- See System.Traces for more details.
-
- -----------------------
- -- Task Image Length --
- -----------------------
-
- Max_Task_Image_Length : constant := 32;
- -- This constant specifies the maximum length of a task's image
-
- ------------------------------
- -- Exception Message Length --
- ------------------------------
-
- Default_Exception_Msg_Max_Length : constant := 200;
- -- This constant specifies the default number of characters to allow
- -- in an exception message (200 is minimum required by RM 11.4.1(18)).
-
-end System.Parameters;
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