gcc/ada/5wsystem.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                        GNAT RUN-TIME COMPONENTS                          --
   4 --                                                                          --
   5 --                               S Y S T E M                                --
   6 --                                                                          --
   7 --                                 S p e c                                  --
   8 --                               (NT Version)                               --
   9 --                                                                          --
  10 --                                                                          --
  11 --          Copyright (C) 1992-2002 Free Software Foundation, Inc.          --
  12 --                                                                          --
  13 -- This specification is derived from the Ada Reference Manual for use with --
  14 -- GNAT. The copyright notice above, and the license provisions that follow --
  15 -- apply solely to the  contents of the part following the private keyword. --
  16 --                                                                          --
  17 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
  18 -- terms of the  GNU General Public License as published  by the Free Soft- --
  19 -- ware  Foundation;  either version 2,  or (at your option) any later ver- --
  20 -- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
  21 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  22 -- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
  23 -- for  more details.  You should have  received  a copy of the GNU General --
  24 -- Public License  distributed with GNAT;  see file COPYING.  If not, write --
  25 -- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
  26 -- MA 02111-1307, USA.                                                      --
  27 --                                                                          --
  28 -- As a special exception,  if other files  instantiate  generics from this --
  29 -- unit, or you link  this unit with other files  to produce an executable, --
  30 -- this  unit  does not  by itself cause  the resulting  executable  to  be --
  31 -- covered  by the  GNU  General  Public  License.  This exception does not --
  32 -- however invalidate  any other reasons why  the executable file  might be --
  33 -- covered by the  GNU Public License.                                      --
  34 --                                                                          --
  35 -- GNAT was originally developed  by the GNAT team at  New York University. --
  36 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  37 --                                                                          --
  38 ------------------------------------------------------------------------------
  39
  40 package System is
  41 pragma Pure (System);
  42 --  Note that we take advantage of the implementation permission to
  43 --  make this unit Pure instead of Preelaborable, see RM 13.7(36)
  44
  45    type Name is (SYSTEM_NAME_GNAT);
  46    System_Name : constant Name := SYSTEM_NAME_GNAT;
  47
  48    --  System-Dependent Named Numbers
  49
  50    Min_Int               : constant := Long_Long_Integer'First;
  51    Max_Int               : constant := Long_Long_Integer'Last;
  52
  53    Max_Binary_Modulus    : constant := 2 ** Long_Long_Integer'Size;
  54    Max_Nonbinary_Modulus : constant := Integer'Last;
  55
  56    Max_Base_Digits       : constant := Long_Long_Float'Digits;
  57    Max_Digits            : constant := Long_Long_Float'Digits;
  58
  59    Max_Mantissa          : constant := 63;
  60    Fine_Delta            : constant := 2.0 ** (-Max_Mantissa);
  61
  62    Tick                  : constant := 1.0;
  63
  64    --  Storage-related Declarations
  65
  66    type Address is private;
  67    Null_Address : constant Address;
  68
  69    Storage_Unit : constant := 8;
  70    Word_Size    : constant := 32;
  71    Memory_Size  : constant := 2 ** 32;
  72
  73    --  Address comparison
  74
  75    function "<"  (Left, Right : Address) return Boolean;
  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
  81    pragma Import (Intrinsic, "<");
  82    pragma Import (Intrinsic, "<=");
  83    pragma Import (Intrinsic, ">");
  84    pragma Import (Intrinsic, ">=");
  85    pragma Import (Intrinsic, "=");
  86
  87    --  Other System-Dependent Declarations
  88
  89    type Bit_Order is (High_Order_First, Low_Order_First);
  90    Default_Bit_Order : constant Bit_Order := Low_Order_First;
  91
  92    --  Priority-related Declarations (RM D.1)
  93
  94    Max_Priority           : constant Positive := 30;
  95    Max_Interrupt_Priority : constant Positive := 31;
  96
  97    subtype Any_Priority       is Integer      range  0 .. 31;
  98    subtype Priority           is Any_Priority range  0 .. 30;
  99    subtype Interrupt_Priority is Any_Priority range 31 .. 31;
 100
 101    Default_Priority : constant Priority := 15;
 102
 103 private
 104
 105    type Address is mod Memory_Size;
 106    Null_Address : constant Address := 0;
 107
 108    --------------------------------------
 109    -- System Implementation Parameters --
 110    --------------------------------------
 111
 112    --  These parameters provide information about the target that is used
 113    --  by the compiler. They are in the private part of System, where they
 114    --  can be accessed using the special circuitry in the Targparm unit
 115    --  whose source should be consulted for more detailed descriptions
 116    --  of the individual switch values.
 117
 118    AAMP                      : constant Boolean := False;
 119    Backend_Divide_Checks     : constant Boolean := False;
 120    Backend_Overflow_Checks   : constant Boolean := False;
 121    Command_Line_Args         : constant Boolean := True;
 122    Denorm                    : constant Boolean := True;
 123    Fractional_Fixed_Ops      : constant Boolean := False;
 124    Frontend_Layout           : constant Boolean := False;
 125    Functions_Return_By_DSP   : constant Boolean := False;
 126    Long_Shifts_Inlined       : constant Boolean := True;
 127    High_Integrity_Mode       : constant Boolean := False;
 128    Machine_Overflows         : constant Boolean := False;
 129    Machine_Rounds            : constant Boolean := True;
 130    OpenVMS                   : constant Boolean := False;
 131    Signed_Zeros              : constant Boolean := True;
 132    Stack_Check_Default       : constant Boolean := False;
 133    Stack_Check_Probes        : constant Boolean := False;
 134    Use_Ada_Main_Program_Name : constant Boolean := False;
 135    ZCX_By_Default            : constant Boolean := False;
 136    GCC_ZCX_Support           : constant Boolean := False;
 137    Front_End_ZCX_Support     : constant Boolean := True;
 138
 139    ---------------------------
 140    -- Underlying Priorities --
 141    ---------------------------
 142
 143    --  Important note: this section of the file must come AFTER the
 144    --  definition of the system implementation parameters to ensure
 145    --  that the value of these parameters is available for analysis
 146    --  of the declarations here (using Rtsfind at compile time).
 147
 148    --  The underlying priorities table provides a generalized mechanism
 149    --  for mapping from Ada priorities to system priorities. In some
 150    --  cases a 1-1 mapping is not the convenient or optimal choice.
 151
 152    type Priorities_Mapping is array (Any_Priority) of Integer;
 153    pragma Suppress_Initialization (Priorities_Mapping);
 154    --  Suppress initialization in case gnat.adc specifies Normalize_Scalars
 155
 156    --  On NT, the default mapping preserves the standard 31 priorities
 157    --  of the Ada model, but maps them using compression onto the 7
 158    --  priority levels available in NT.
 159
 160    --  To replace the default values of the Underlying_Priorities mapping,
 161    --  copy this source file into your build directory, edit the file to
 162    --  reflect your desired behavior, and recompile with the command:
 163
 164    --     $ gcc -c -O3 -gnatpgn system.ads
 165
 166    --  then recompile the run-time parts that depend on this package:
 167
 168    --     $ gnatmake -a -gnatn -O3 <your application>
 169
 170    --  then force rebuilding your application if you need different options:
 171
 172    --     $ gnatmake -f <your options> <your application>
 173
 174    Underlying_Priorities : constant Priorities_Mapping :=
 175
 176      (Priority'First .. 1        => -15,
 177
 178       2 .. Default_Priority - 2  => -2,
 179
 180       Default_Priority - 1       => -1,
 181
 182       Default_Priority           => 0,
 183
 184       Default_Priority + 1 .. 19 => 1,
 185
 186       20 .. Priority'Last        => 2,
 187
 188       Interrupt_Priority         => 15);
 189
 190    pragma Linker_Options ("-Wl,--stack=0x2000000");
 191    --  This is used to change the default stack (32 MB) size for non tasking
 192    --  programs. We change this value for GNAT on Windows here because the
 193    --  binutils on this platform have switched to a too low value for Ada
 194    --  programs. Note that we also set the stack size for tasking programs in
 195    --  System.Task_Primitives.Operations.
 196
 197 end System;