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) 1992-2018, 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------------------------------------------------------------------------------ 31 32-- This is the HP version of this package 33 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. 37 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. 41 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. 45 46-- Note: do not introduce any pragma Inline statements into this unit, since 47-- otherwise the relinking and rebinding capability would be deactivated. 48 49package System.Parameters is 50 pragma Pure; 51 52 --------------------------------------- 53 -- Task And Stack Allocation Control -- 54 --------------------------------------- 55 56 type Task_Storage_Size is new Integer; 57 -- Type used in tasking units for task storage size 58 59 type Size_Type is new Task_Storage_Size; 60 -- Type used to provide task storage size to runtime 61 62 Unspecified_Size : constant Size_Type := Size_Type'First; 63 -- Value used to indicate that no size type is set 64 65 function Default_Stack_Size return Size_Type; 66 -- Default task stack size used if none is specified 67 68 function Minimum_Stack_Size return Size_Type; 69 -- Minimum task stack size permitted 70 71 function Adjust_Storage_Size (Size : Size_Type) return Size_Type; 72 -- Given the storage size stored in the TCB, return the Storage_Size 73 -- value required by the RM for the Storage_Size attribute. The 74 -- required adjustment is as follows: 75 -- 76 -- when Size = Unspecified_Size, return Default_Stack_Size 77 -- when Size < Minimum_Stack_Size, return Minimum_Stack_Size 78 -- otherwise return given Size 79 80 Default_Env_Stack_Size : constant Size_Type := 8_192_000; 81 -- Assumed size of the environment task, if no other information 82 -- is available. This value is used when stack checking is 83 -- enabled and no GNAT_STACK_LIMIT environment variable is set. 84 85 Stack_Grows_Down : constant Boolean := False; 86 -- This constant indicates whether the stack grows up (False) or 87 -- down (True) in memory as functions are called. It is used for 88 -- proper implementation of the stack overflow check. 89 90 Runtime_Default_Sec_Stack_Size : constant Size_Type := 10 * 1024; 91 -- The run-time chosen default size for secondary stacks that may be 92 -- overriden by the user with the use of binder -D switch. 93 94 Sec_Stack_Dynamic : constant Boolean := True; 95 -- Indicates if secondary stacks can grow and shrink at run-time. If False, 96 -- the size of a secondary stack is fixed at the point of its creation. 97 98 ---------------------------------------------- 99 -- Characteristics of Types in Interfaces.C -- 100 ---------------------------------------------- 101 102 long_bits : constant := Long_Integer'Size; 103 -- Number of bits in type long and unsigned_long. The normal convention 104 -- is that this is the same as type Long_Integer, but this may not be true 105 -- of all targets. 106 107 ptr_bits : constant := Standard'Address_Size; 108 subtype C_Address is System.Address; 109 -- Number of bits in Interfaces.C pointers, normally a standard address 110 111 C_Malloc_Linkname : constant String := "__gnat_malloc"; 112 -- Name of runtime function used to allocate such a pointer 113 114 ---------------------------------------------- 115 -- Behavior of Pragma Finalize_Storage_Only -- 116 ---------------------------------------------- 117 118 -- Garbage_Collected is a Boolean constant whose value indicates the 119 -- effect of the pragma Finalize_Storage_Entry on a controlled type. 120 121 -- Garbage_Collected = False 122 123 -- The system releases all storage on program termination only, 124 -- but not other garbage collection occurs, so finalization calls 125 -- are omitted only for outer level objects can be omitted if 126 -- pragma Finalize_Storage_Only is used. 127 128 -- Garbage_Collected = True 129 130 -- The system provides full garbage collection, so it is never 131 -- necessary to release storage for controlled objects for which 132 -- a pragma Finalize_Storage_Only is used. 133 134 Garbage_Collected : constant Boolean := False; 135 -- The storage mode for this system (release on program exit) 136 137 --------------------- 138 -- Tasking Profile -- 139 --------------------- 140 141 -- In the following sections, constant parameters are defined to 142 -- allow some optimizations and fine tuning within the tasking run time 143 -- based on restrictions on the tasking features. 144 145 ---------------------- 146 -- Locking Strategy -- 147 ---------------------- 148 149 Single_Lock : constant Boolean := False; 150 -- Indicates whether a single lock should be used within the tasking 151 -- run-time to protect internal structures. If True, a single lock 152 -- will be used, meaning less locking/unlocking operations, but also 153 -- more global contention. In general, Single_Lock should be set to 154 -- True on single processor machines, and to False to multi-processor 155 -- systems, but this can vary from application to application and also 156 -- depends on the scheduling policy. 157 158 ------------------- 159 -- Task Abortion -- 160 ------------------- 161 162 No_Abort : constant Boolean := False; 163 -- This constant indicates whether abort statements and asynchronous 164 -- transfer of control (ATC) are disallowed. If set to True, it is 165 -- assumed that neither construct is used, and the run time does not 166 -- need to defer/undefer abort and check for pending actions at 167 -- completion points. A value of True for No_Abort corresponds to: 168 -- pragma Restrictions (No_Abort_Statements); 169 -- pragma Restrictions (Max_Asynchronous_Select_Nesting => 0); 170 171 --------------------- 172 -- Task Attributes -- 173 --------------------- 174 175 Max_Attribute_Count : constant := 32; 176 -- Number of task attributes stored in the task control block 177 178 ----------------------- 179 -- Task Image Length -- 180 ----------------------- 181 182 Max_Task_Image_Length : constant := 256; 183 -- This constant specifies the maximum length of a task's image 184 185 ------------------------------ 186 -- Exception Message Length -- 187 ------------------------------ 188 189 Default_Exception_Msg_Max_Length : constant := 200; 190 -- This constant specifies the default number of characters to allow 191 -- in an exception message (200 is minimum required by RM 11.4.1(18)). 192 193end System.Parameters; 194