gcc/ada/libgnat/system-mingw.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                        GNAT RUN-TIME COMPONENTS                          --
   4 --                                                                          --
   5 --                               S Y S T E M                                --
   6 --                                                                          --
   7 --                                 S p e c                                  --
   8 --                            (Windows Version)                             --
   9 --                                                                          --
  10 --          Copyright (C) 1992-2019, Free Software Foundation, Inc.         --
  11 --                                                                          --
  12 -- This specification is derived from the Ada Reference Manual for use with --
  13 -- GNAT. The copyright notice above, and the license provisions that follow --
  14 -- apply solely to the  contents of the part following the private keyword. --
  15 --                                                                          --
  16 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
  17 -- terms of the  GNU General Public License as published  by the Free Soft- --
  18 -- ware  Foundation;  either version 3,  or (at your option) any later ver- --
  19 -- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
  20 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  21 -- or FITNESS FOR A PARTICULAR PURPOSE.                                     --
  22 --                                                                          --
  23 -- As a special exception under Section 7 of GPL version 3, you are granted --
  24 -- additional permissions described in the GCC Runtime Library Exception,   --
  25 -- version 3.1, as published by the Free Software Foundation.               --
  26 --                                                                          --
  27 -- You should have received a copy of the GNU General Public License and    --
  28 -- a copy of the GCC Runtime Library Exception along with this program;     --
  29 -- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
  30 -- <http://www.gnu.org/licenses/>.                                          --
  31 --                                                                          --
  32 -- GNAT was originally developed  by the GNAT team at  New York University. --
  33 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  34 --                                                                          --
  35 ------------------------------------------------------------------------------
  36
  37 package System is
  38    pragma Pure;
  39    --  Note that we take advantage of the implementation permission to make
  40    --  this unit Pure instead of Preelaborable; see RM 13.7.1(15). In Ada
  41    --  2005, this is Pure in any case (AI-362).
  42
  43    pragma No_Elaboration_Code_All;
  44    --  Allow the use of that restriction in units that WITH this unit
  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 := 2 ** Integer'Size - 1;
  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 := 0.01;
  64
  65    --  Storage-related Declarations
  66
  67    type Address is private;
  68    pragma Preelaborable_Initialization (Address);
  69    Null_Address : constant Address;
  70
  71    Storage_Unit : constant := 8;
  72    Word_Size    : constant := Standard'Word_Size;
  73    Memory_Size  : constant := 2 ** Word_Size;
  74
  75    --  Address comparison
  76
  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    function "="  (Left, Right : Address) return Boolean;
  82
  83    pragma Import (Intrinsic, "<");
  84    pragma Import (Intrinsic, "<=");
  85    pragma Import (Intrinsic, ">");
  86    pragma Import (Intrinsic, ">=");
  87    pragma Import (Intrinsic, "=");
  88
  89    --  Other System-Dependent Declarations
  90
  91    type Bit_Order is (High_Order_First, Low_Order_First);
  92    Default_Bit_Order : constant Bit_Order := Low_Order_First;
  93    pragma Warnings (Off, Default_Bit_Order); -- kill constant condition warning
  94
  95    --  Priority-related Declarations (RM D.1)
  96
  97    Max_Priority           : constant Positive := 30;
  98    Max_Interrupt_Priority : constant Positive := 31;
  99
 100    subtype Any_Priority       is Integer      range  0 .. 31;
 101    subtype Priority           is Any_Priority range  0 .. 30;
 102    subtype Interrupt_Priority is Any_Priority range 31 .. 31;
 103
 104    Default_Priority : constant Priority := 15;
 105
 106 private
 107
 108    type Address is mod Memory_Size;
 109    Null_Address : constant Address := 0;
 110
 111    --------------------------------------
 112    -- System Implementation Parameters --
 113    --------------------------------------
 114
 115    --  These parameters provide information about the target that is used
 116    --  by the compiler. They are in the private part of System, where they
 117    --  can be accessed using the special circuitry in the Targparm unit
 118    --  whose source should be consulted for more detailed descriptions
 119    --  of the individual switch values.
 120
 121    Backend_Divide_Checks     : constant Boolean := False;
 122    Backend_Overflow_Checks   : constant Boolean := True;
 123    Command_Line_Args         : constant Boolean := True;
 124    Configurable_Run_Time     : constant Boolean := False;
 125    Denorm                    : constant Boolean := True;
 126    Duration_32_Bits          : constant Boolean := False;
 127    Exit_Status_Supported     : constant Boolean := True;
 128    Fractional_Fixed_Ops      : constant Boolean := False;
 129    Frontend_Layout           : constant Boolean := False;
 130    Machine_Overflows         : constant Boolean := False;
 131    Machine_Rounds            : constant Boolean := True;
 132    Preallocated_Stacks       : constant Boolean := False;
 133    Signed_Zeros              : constant Boolean := True;
 134    Stack_Check_Default       : constant Boolean := False;
 135    Stack_Check_Probes        : constant Boolean := True;
 136    Stack_Check_Limits        : constant Boolean := False;
 137    Support_Aggregates        : constant Boolean := True;
 138    Support_Atomic_Primitives : constant Boolean := True;
 139    Support_Composite_Assign  : constant Boolean := True;
 140    Support_Composite_Compare : constant Boolean := True;
 141    Support_Long_Shifts       : constant Boolean := True;
 142    Always_Compatible_Rep     : constant Boolean := False;
 143    Suppress_Standard_Library : constant Boolean := False;
 144    Use_Ada_Main_Program_Name : constant Boolean := False;
 145    Frontend_Exceptions       : constant Boolean := False;
 146    ZCX_By_Default            : constant Boolean := True;
 147
 148    ---------------------------
 149    -- Underlying Priorities --
 150    ---------------------------
 151
 152    --  Important note: this section of the file must come AFTER the
 153    --  definition of the system implementation parameters to ensure
 154    --  that the value of these parameters is available for analysis
 155    --  of the declarations here (using Rtsfind at compile time).
 156
 157    --  The underlying priorities table provides a generalized mechanism
 158    --  for mapping from Ada priorities to system priorities. In some
 159    --  cases a 1-1 mapping is not the convenient or optimal choice.
 160
 161    type Priorities_Mapping is array (Any_Priority) of Integer;
 162    pragma Suppress_Initialization (Priorities_Mapping);
 163    --  Suppress initialization in case gnat.adc specifies Normalize_Scalars
 164
 165    Underlying_Priorities : constant Priorities_Mapping :=
 166      (Priority'First ..
 167       Default_Priority - 8    => -15,
 168       Default_Priority - 7    => -7,
 169       Default_Priority - 6    => -6,
 170       Default_Priority - 5    => -5,
 171       Default_Priority - 4    => -4,
 172       Default_Priority - 3    => -3,
 173       Default_Priority - 2    => -2,
 174       Default_Priority - 1    => -1,
 175       Default_Priority        => 0,
 176       Default_Priority + 1    => 1,
 177       Default_Priority + 2    => 2,
 178       Default_Priority + 3    => 3,
 179       Default_Priority + 4    => 4,
 180       Default_Priority + 5    => 5,
 181       Default_Priority + 6 ..
 182       Priority'Last           => 6,
 183       Interrupt_Priority      => 15);
 184    --  The default mapping preserves the standard 31 priorities of the Ada
 185    --  model, but maps them using compression onto the 7 priority levels
 186    --  available in NT and on the 16 priority levels available in 2000/XP.
 187
 188    pragma Linker_Options ("-Wl,--stack=0x2000000");
 189    --  This is used to change the default stack (32 MB) size for non tasking
 190    --  programs. We change this value for GNAT on Windows here because the
 191    --  binutils on this platform have switched to a too low value for Ada
 192    --  programs. Note that we also set the stack size for tasking programs in
 193    --  System.Task_Primitives.Operations.
 194
 195 end System;