gcc/ada/5asystem.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                        GNAT RUN-TIME COMPONENTS                          --
   4 --                                                                          --
   5 --                               S Y S T E M                                --
   6 --                                                                          --
   7 --                                 S p e c                                  --
   8 --                           (DEC Unix Version)                             --
   9 --                                                                          --
  10 --                            $Revision: 1.20 $
  11 --                                                                          --
  12 --          Copyright (C) 1992-2001 Free Software Foundation, Inc.          --
  13 --                                                                          --
  14 -- This specification is derived from the Ada Reference Manual for use with --
  15 -- GNAT. The copyright notice above, and the license provisions that follow --
  16 -- apply solely to the  contents of the part following the private keyword. --
  17 --                                                                          --
  18 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
  19 -- terms of the  GNU General Public License as published  by the Free Soft- --
  20 -- ware  Foundation;  either version 2,  or (at your option) any later ver- --
  21 -- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
  22 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  23 -- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
  24 -- for  more details.  You should have  received  a copy of the GNU General --
  25 -- Public License  distributed with GNAT;  see file COPYING.  If not, write --
  26 -- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
  27 -- MA 02111-1307, USA.                                                      --
  28 --                                                                          --
  29 -- As a special exception,  if other files  instantiate  generics from this --
  30 -- unit, or you link  this unit with other files  to produce an executable, --
  31 -- this  unit  does not  by itself cause  the resulting  executable  to  be --
  32 -- covered  by the  GNU  General  Public  License.  This exception does not --
  33 -- however invalidate  any other reasons why  the executable file  might be --
  34 -- covered by the  GNU Public License.                                      --
  35 --                                                                          --
  36 -- GNAT was originally developed  by the GNAT team at  New York University. --
  37 -- It is now maintained by Ada Core Technologies Inc (http://www.gnat.com). --
  38 --                                                                          --
  39 ------------------------------------------------------------------------------
  40
  41 package System is
  42 pragma Pure (System);
  43 --  Note that we take advantage of the implementation permission to
  44 --  make this unit Pure instead of Preelaborable, see RM 13.7(36)
  45
  46    type Name is (SYSTEM_NAME_GNAT);
  47    System_Name : constant Name := SYSTEM_NAME_GNAT;
  48
  49    --  System-Dependent Named Numbers
  50
  51    Min_Int               : constant := Long_Long_Integer'First;
  52    Max_Int               : constant := Long_Long_Integer'Last;
  53
  54    Max_Binary_Modulus    : constant := 2 ** Long_Long_Integer'Size;
  55    Max_Nonbinary_Modulus : constant := Integer'Last;
  56
  57    Max_Base_Digits       : constant := Long_Long_Float'Digits;
  58    Max_Digits            : constant := Long_Long_Float'Digits;
  59
  60    Max_Mantissa          : constant := 63;
  61    Fine_Delta            : constant := 2.0 ** (-Max_Mantissa);
  62
  63    Tick                  : constant := Standard'Tick;
  64
  65    --  Storage-related Declarations
  66
  67    type Address is private;
  68    Null_Address : constant Address;
  69
  70    Storage_Unit : constant := Standard'Storage_Unit;
  71    Word_Size    : constant := Standard'Word_Size;
  72    Memory_Size  : constant := 2 ** Standard'Address_Size;
  73
  74    --  Address comparison
  75
  76    function "<"  (Left, Right : Address) return Boolean;
  77    function "<=" (Left, Right : Address) return Boolean;
  78    function ">"  (Left, Right : Address) return Boolean;
  79    function ">=" (Left, Right : Address) return Boolean;
  80    function "="  (Left, Right : Address) return Boolean;
  81
  82    pragma Import (Intrinsic, "<");
  83    pragma Import (Intrinsic, "<=");
  84    pragma Import (Intrinsic, ">");
  85    pragma Import (Intrinsic, ">=");
  86    pragma Import (Intrinsic, "=");
  87
  88    --  Other System-Dependent Declarations
  89
  90    type Bit_Order is (High_Order_First, Low_Order_First);
  91    Default_Bit_Order : constant Bit_Order := Low_Order_First;
  92
  93    --  Priority-related Declarations (RM D.1)
  94
  95    Max_Priority : constant Positive := 30;
  96
  97    Max_Interrupt_Priority : constant Positive := 31;
  98
  99    subtype Any_Priority is Integer
 100      range 0 .. Standard'Max_Interrupt_Priority;
 101
 102    subtype Priority is Any_Priority
 103      range 0 .. Standard'Max_Priority;
 104
 105    --  Functional notation is needed in the following to avoid visibility
 106    --  problems when this package is compiled through rtsfind in the middle
 107    --  of another compilation.
 108
 109    subtype Interrupt_Priority is Any_Priority
 110      range
 111        Standard."+" (Standard'Max_Priority,  1) ..
 112          Standard'Max_Interrupt_Priority;
 113
 114    Default_Priority : constant Priority :=
 115      Standard."/" (Standard."+" (Priority'First, Priority'Last), 2);
 116
 117 private
 118
 119    type Address is mod Memory_Size;
 120    Null_Address : constant Address := 0;
 121
 122    --------------------------------------
 123    -- System Implementation Parameters --
 124    --------------------------------------
 125
 126    --  These parameters provide information about the target that is used
 127    --  by the compiler. They are in the private part of System, where they
 128    --  can be accessed using the special circuitry in the Targparm unit
 129    --  whose source should be consulted for more detailed descriptions
 130    --  of the individual switch values.
 131
 132    AAMP                      : constant Boolean := False;
 133    Command_Line_Args         : constant Boolean := True;
 134    Denorm                    : constant Boolean := False;
 135    Frontend_Layout           : constant Boolean := False;
 136    Functions_Return_By_DSP   : constant Boolean := True;
 137    Long_Shifts_Inlined       : constant Boolean := True;
 138    High_Integrity_Mode       : constant Boolean := False;
 139    Machine_Overflows         : constant Boolean := False;
 140    Machine_Rounds            : constant Boolean := True;
 141    OpenVMS                   : constant Boolean := False;
 142    Signed_Zeros              : constant Boolean := True;
 143    Stack_Check_Default       : constant Boolean := True;
 144    Stack_Check_Probes        : constant Boolean := True;
 145    Use_Ada_Main_Program_Name : constant Boolean := False;
 146    ZCX_By_Default            : constant Boolean := True;
 147    GCC_ZCX_Support           : constant Boolean := False;
 148    Front_End_ZCX_Support     : constant Boolean := True;
 149
 150    --  Note: Denorm is False because denormals are only handled properly
 151    --  if the -mieee switch is set, and we do not require this usage.
 152
 153    ---------------------------
 154    -- Underlying Priorities --
 155    ---------------------------
 156
 157    --  Important note: this section of the file must come AFTER the
 158    --  definition of the system implementation parameters to ensure
 159    --  that the value of these parameters is available for analysis
 160    --  of the declarations here (using Rtsfind at compile time).
 161
 162    --  The underlying priorities table provides a generalized mechanism
 163    --  for mapping from Ada priorities to system priorities. In some
 164    --  cases a 1-1 mapping is not the convenient or optimal choice.
 165
 166    --  For Dec Unix 4.0d, we use a default 1-to-1 mapping that provides
 167    --  the full range of 64 priorities available from the operating system.
 168
 169    --  On DU prior to 4.0d, less than 64 priorities are available so there
 170    --  are two possibilities:
 171
 172    --    Limit your range of priorities to the range provided by the
 173    --    OS (e.g 16 .. 32 on 4.0b)
 174
 175    --    Replace the standard table as described below
 176
 177    --  To replace the default values of the Underlying_Priorities mapping,
 178    --  copy this source file into your build directory, edit the file to
 179    --  reflect your desired behavior, and recompile with the command:
 180
 181    --     $ gcc -c -O3 -gnatpgn system.ads
 182
 183    --  then recompile the run-time parts that depend on this package:
 184
 185    --     $ gnatmake -a -gnatn -O3 <your application>
 186
 187    --  then force rebuilding your application if you need different options:
 188
 189    --     $ gnatmake -f <your options> <your application>
 190
 191    type Priorities_Mapping is array (Any_Priority) of Integer;
 192    pragma Suppress_Initialization (Priorities_Mapping);
 193    --  Suppress initialization in case gnat.adc specifies Normalize_Scalars
 194
 195    Underlying_Priorities : constant Priorities_Mapping :=
 196      (Priority'First     => 16,
 197       1  => 17,
 198       2  => 18,
 199       3  => 18,
 200       4  => 18,
 201       5  => 18,
 202       6  => 19,
 203       7  => 19,
 204       8  => 19,
 205       9  => 20,
 206       10 => 20,
 207       11 => 21,
 208       12 => 21,
 209       13 => 22,
 210       14 => 23,
 211       Default_Priority   => 24,
 212       16 => 25,
 213       17 => 25,
 214       18 => 25,
 215       19 => 26,
 216       20 => 26,
 217       21 => 26,
 218       22 => 27,
 219       23 => 27,
 220       24 => 27,
 221       25 => 28,
 222       26 => 28,
 223       27 => 29,
 224       28 => 29,
 225       29 => 30,
 226       Priority'Last      => 30,
 227       Interrupt_Priority => 31);
 228
 229 end System;