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------------------------------------------------------------------------------

--                                                                          --

--                        GNAT RUN-TIME COMPONENTS                          --

--                                                                          --

--                               S Y S T E M                                --

--                                                                          --

--                                 S p e c                                  --

--                           (DEC Unix Version)                             --

--                                                                          --

--          Copyright (C) 1992-2011, Free Software Foundation, Inc.         --

--                                                                          --

-- This specification is derived from the Ada Reference Manual for use with --

-- GNAT. The copyright notice above, and the license provisions that follow --

-- apply solely to the  contents of the part following the private keyword. --

--                                                                          --

-- 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.      --

--                                                                          --

------------------------------------------------------------------------------

package System is

   pragma Pure;

   --  Note that we take advantage of the implementation permission to make

   --  this unit Pure instead of Preelaborable; see RM 13.7.1(15). In Ada

   --  2005, this is Pure in any case (AI-362).

   type Name is (SYSTEM_NAME_GNAT);

   System_Name : constant Name := SYSTEM_NAME_GNAT;

   --  System-Dependent Named Numbers

   Min_Int               : constant := Long_Long_Integer'First;

   Max_Int               : constant := Long_Long_Integer'Last;

   Max_Binary_Modulus    : constant := 2 ** Long_Long_Integer'Size;

   Max_Nonbinary_Modulus : constant := 2 ** Integer'Size - 1;

   Max_Base_Digits       : constant := Long_Long_Float'Digits;

   Max_Digits            : constant := Long_Long_Float'Digits;

   Max_Mantissa          : constant := 63;

   Fine_Delta            : constant := 2.0 ** (-Max_Mantissa);

   Tick                  : constant := 1.0 / 1024.0;

   --  Storage-related Declarations

   type Address is private;

   pragma Preelaborable_Initialization (Address);

   Null_Address : constant Address;

   Storage_Unit : constant := 8;

   Word_Size    : constant := 64;

   Memory_Size  : constant := 2 ** 64;

   --  Address comparison

   function "<"  (Left, Right : Address) return Boolean;

   function "<=" (Left, Right : Address) return Boolean;

   function ">"  (Left, Right : Address) return Boolean;

   function ">=" (Left, Right : Address) return Boolean;

   function "="  (Left, Right : Address) return Boolean;

   pragma Import (Intrinsic, "<");

   pragma Import (Intrinsic, "<=");

   pragma Import (Intrinsic, ">");

   pragma Import (Intrinsic, ">=");

   pragma Import (Intrinsic, "=");

   --  Other System-Dependent Declarations

   type Bit_Order is (High_Order_First, Low_Order_First);

   Default_Bit_Order : constant Bit_Order := Low_Order_First;

   pragma Warnings (Off, Default_Bit_Order); -- kill constant condition warning

   --  Priority-related Declarations (RM D.1)

   Max_Priority           : constant Positive := 60;

   Max_Interrupt_Priority : constant Positive := 63;

   subtype Any_Priority       is Integer      range  0 .. 63;

   subtype Priority           is Any_Priority range  0 .. 60;

   subtype Interrupt_Priority is Any_Priority range 61 .. 63;

   Default_Priority : constant Priority := 30;

private

   type Address is mod Memory_Size;

   Null_Address : constant Address := 0;

   --------------------------------------

   -- System Implementation Parameters --

   --------------------------------------

   --  These parameters provide information about the target that is used

   --  by the compiler. They are in the private part of System, where they

   --  can be accessed using the special circuitry in the Targparm unit

   --  whose source should be consulted for more detailed descriptions

   --  of the individual switch values.

   Backend_Divide_Checks     : constant Boolean := False;

   Backend_Overflow_Checks   : constant Boolean := True;

   Command_Line_Args         : constant Boolean := True;

   Configurable_Run_Time     : constant Boolean := False;

   Denorm                    : constant Boolean := False;

   Duration_32_Bits          : constant Boolean := False;

   Exit_Status_Supported     : constant Boolean := True;

   Fractional_Fixed_Ops      : constant Boolean := False;

   Frontend_Layout           : constant Boolean := False;

   Machine_Overflows         : constant Boolean := False;

   Machine_Rounds            : constant Boolean := True;

   Preallocated_Stacks       : constant Boolean := False;

   Signed_Zeros              : constant Boolean := True;

   Stack_Check_Default       : constant Boolean := True;

   Stack_Check_Probes        : constant Boolean := True;

   Stack_Check_Limits        : constant Boolean := False;

   Support_Aggregates        : constant Boolean := True;

   Support_Composite_Assign  : constant Boolean := True;

   Support_Composite_Compare : constant Boolean := True;

   Support_Long_Shifts       : constant Boolean := True;

   Always_Compatible_Rep     : constant Boolean := True;

   Suppress_Standard_Library : constant Boolean := False;

   Use_Ada_Main_Program_Name : constant Boolean := False;

   ZCX_By_Default            : constant Boolean := True;

   --  Note: Denorm is False because denormals are only handled properly

   --  if the -mieee switch is set, and we do not require this usage.

   ---------------------------

   -- Underlying Priorities --

   ---------------------------

   --  Important note: this section of the file must come AFTER the

   --  definition of the system implementation parameters to ensure

   --  that the value of these parameters is available for analysis

   --  of the declarations here (using Rtsfind at compile time).

   --  The underlying priorities table provides a generalized mechanism

   --  for mapping from Ada priorities to system priorities. In some

   --  cases a 1-1 mapping is not the convenient or optimal choice.

   --  For Dec Unix 4.0d, we use a default 1-to-1 mapping that provides

   --  the full range of 64 priorities available from the operating system.

   --  On DU prior to 4.0d, less than 64 priorities are available so there

   --  are two possibilities:

   --    Limit your range of priorities to the range provided by the

   --    OS (e.g 16 .. 32 on 4.0b)

   --    Replace the standard table as described below

   --  To replace the default values of the Underlying_Priorities mapping,

   --  copy this source file into your build directory, edit the file to

   --  reflect your desired behavior, and recompile with the command:

   --     $ gcc -c -O3 -gnatpgn system.ads

   --  then recompile the run-time parts that depend on this package:

   --     $ gnatmake -a -gnatn -O3 <your application>

   --  then force rebuilding your application if you need different options:

   --     $ gnatmake -f <your options> <your application>

   type Priorities_Mapping is array (Any_Priority) of Integer;

   pragma Suppress_Initialization (Priorities_Mapping);

   --  Suppress initialization in case gnat.adc specifies Normalize_Scalars

   Underlying_Priorities : constant Priorities_Mapping :=

     (Priority'First => 0,

       1 =>  1,  2 =>  2,  3 =>  3,  4 =>  4,  5 =>  5,

       6 =>  6,  7 =>  7,  8 =>  8,  9 =>  9, 10 => 10,

      11 => 11, 12 => 12, 13 => 13, 14 => 14, 15 => 15,

      16 => 16, 17 => 17, 18 => 18, 19 => 19, 20 => 20,

      21 => 21, 22 => 22, 23 => 23, 24 => 24, 25 => 25,

      26 => 26, 27 => 27, 28 => 28, 29 => 29,

      Default_Priority => 30,

      31 => 31, 32 => 32, 33 => 33, 34 => 34, 35 => 35,

      36 => 36, 37 => 37, 38 => 38, 39 => 39, 40 => 40,

      41 => 41, 42 => 42, 43 => 43, 44 => 44, 45 => 45,

      46 => 46, 47 => 47, 48 => 48, 49 => 49, 50 => 50,

      51 => 51, 52 => 52, 53 => 53, 54 => 54, 55 => 55,

      56 => 56, 57 => 57, 58 => 58, 59 => 59,

      Priority'Last => 60,

      61 => 61, 62 => 62,

      Interrupt_Priority'Last => 63);

end System;