gcc/ada/system-vms_64.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                        GNAT RUN-TIME COMPONENTS                          --
   4 --                                                                          --
   5 --                               S Y S T E M                                --
   6 --                                                                          --
   7 --                                 S p e c                                  --
   8 --                (OpenVMS 64bit GCC_ZCX DEC Threads Version)               --
   9 --                                                                          --
  10 --          Copyright (C) 1992-2012, 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    type Name is (SYSTEM_NAME_GNAT);
  44    System_Name : constant Name := SYSTEM_NAME_GNAT;
  45
  46    --  System-Dependent Named Numbers
  47
  48    Min_Int               : constant := Long_Long_Integer'First;
  49    Max_Int               : constant := Long_Long_Integer'Last;
  50
  51    Max_Binary_Modulus    : constant := 2 ** Long_Long_Integer'Size;
  52    Max_Nonbinary_Modulus : constant := 2 ** Integer'Size - 1;
  53
  54    Max_Base_Digits       : constant := Long_Long_Float'Digits;
  55    Max_Digits            : constant := Long_Long_Float'Digits;
  56
  57    Max_Mantissa          : constant := 63;
  58    Fine_Delta            : constant := 2.0 ** (-Max_Mantissa);
  59
  60    Tick                  : constant := 0.01;
  61
  62    --  Storage-related Declarations
  63
  64    type Address is new Long_Integer;
  65    Null_Address : constant Address;
  66    --  Although this is declared as an integer type, no arithmetic operations
  67    --  are available (see abstract declarations below), and furthermore there
  68    --  is special processing in the compiler that prevents the use of integer
  69    --  literals with this type (use To_Address to convert integer literals).
  70    --
  71    --  Conversion to and from Short_Address is however freely permitted, and
  72    --  is indeed the reason that Address is declared as an integer type.
  73
  74    Storage_Unit : constant := 8;
  75    Word_Size    : constant := 64;
  76    Memory_Size  : constant := 2 ** 64;
  77
  78    --  Address comparison
  79
  80    function "<"  (Left, Right : Address) return Boolean;
  81    function "<=" (Left, Right : Address) return Boolean;
  82    function ">"  (Left, Right : Address) return Boolean;
  83    function ">=" (Left, Right : Address) return Boolean;
  84    function "="  (Left, Right : Address) return Boolean;
  85
  86    pragma Import (Intrinsic, "<");
  87    pragma Import (Intrinsic, "<=");
  88    pragma Import (Intrinsic, ">");
  89    pragma Import (Intrinsic, ">=");
  90    pragma Import (Intrinsic, "=");
  91
  92    --  Abstract declarations for arithmetic operations on type address.
  93    --  These declarations are needed when Address is non-private. They
  94    --  avoid excessive visibility of arithmetic operations on address
  95    --  which are typically available elsewhere (e.g. Storage_Elements)
  96    --  and which would cause excessive ambiguities in application code.
  97
  98    function "+"   (Left, Right : Address) return Address is abstract;
  99    function "-"   (Left, Right : Address) return Address is abstract;
 100    function "/"   (Left, Right : Address) return Address is abstract;
 101    function "*"   (Left, Right : Address) return Address is abstract;
 102    function "mod" (Left, Right : Address) return Address is abstract;
 103
 104    --  Other System-Dependent Declarations
 105
 106    type Bit_Order is (High_Order_First, Low_Order_First);
 107    Default_Bit_Order : constant Bit_Order := Low_Order_First;
 108    pragma Warnings (Off, Default_Bit_Order); -- kill constant condition warning
 109
 110    --  Priority-related Declarations (RM D.1)
 111
 112    Max_Priority           : constant Positive := 30;
 113    Max_Interrupt_Priority : constant Positive := 31;
 114
 115    subtype Any_Priority       is Integer      range  0 .. 31;
 116    subtype Priority           is Any_Priority range  0 .. 30;
 117    subtype Interrupt_Priority is Any_Priority range 31 .. 31;
 118
 119    Default_Priority : constant Priority := 15;
 120
 121 private
 122
 123    Null_Address : constant Address := 0;
 124
 125    --------------------------------------
 126    -- System Implementation Parameters --
 127    --------------------------------------
 128
 129    --  These parameters provide information about the target that is used
 130    --  by the compiler. They are in the private part of System, where they
 131    --  can be accessed using the special circuitry in the Targparm unit
 132    --  whose source should be consulted for more detailed descriptions
 133    --  of the individual switch values.
 134
 135    Backend_Divide_Checks     : constant Boolean := False;
 136    Backend_Overflow_Checks   : constant Boolean := True;
 137    Command_Line_Args         : constant Boolean := True;
 138    Configurable_Run_Time     : constant Boolean := False;
 139    Denorm                    : constant Boolean := False;
 140    Duration_32_Bits          : constant Boolean := False;
 141    Exit_Status_Supported     : constant Boolean := True;
 142    Fractional_Fixed_Ops      : constant Boolean := False;
 143    Frontend_Layout           : constant Boolean := False;
 144    Machine_Overflows         : constant Boolean := False;
 145    Machine_Rounds            : constant Boolean := True;
 146    OpenVMS                   : constant Boolean := True;
 147    Preallocated_Stacks       : constant Boolean := False;
 148    Signed_Zeros              : constant Boolean := True;
 149    Stack_Check_Default       : constant Boolean := True;
 150    Stack_Check_Probes        : constant Boolean := True;
 151    Stack_Check_Limits        : constant Boolean := False;
 152    Support_Aggregates        : constant Boolean := True;
 153    Support_Atomic_Primitives : constant Boolean := True;
 154    Support_Composite_Assign  : constant Boolean := True;
 155    Support_Composite_Compare : constant Boolean := True;
 156    Support_Long_Shifts       : constant Boolean := True;
 157    Always_Compatible_Rep     : constant Boolean := True;
 158    Suppress_Standard_Library : constant Boolean := False;
 159    Use_Ada_Main_Program_Name : constant Boolean := False;
 160    ZCX_By_Default            : constant Boolean := True;
 161
 162    --------------------------
 163    -- Underlying Priorities --
 164    ---------------------------
 165
 166    --  Important note: this section of the file must come AFTER the
 167    --  definition of the system implementation parameters to ensure
 168    --  that the value of these parameters is available for analysis
 169    --  of the declarations here (using Rtsfind at compile time).
 170
 171    --  The underlying priorities table provides a generalized mechanism
 172    --  for mapping from Ada priorities to system priorities. In some
 173    --  cases a 1-1 mapping is not the convenient or optimal choice.
 174
 175    --  For DEC Threads OpenVMS, we use the full range of 31 priorities
 176    --  in the Ada model, but map them by compression onto the more limited
 177    --  range of priorities available in OpenVMS.
 178
 179    --  To replace the default values of the Underlying_Priorities mapping,
 180    --  copy this source file into your build directory, edit the file to
 181    --  reflect your desired behavior, and recompile with the command:
 182
 183    --     $ gcc -c -O3 -gnatpgn system.ads
 184
 185    --  then recompile the run-time parts that depend on this package:
 186
 187    --     $ gnatmake -a -gnatn -O3 <your application>
 188
 189    --  then force rebuilding your application if you need different options:
 190
 191    --     $ gnatmake -f <your options> <your application>
 192
 193    type Priorities_Mapping is array (Any_Priority) of Integer;
 194    pragma Suppress_Initialization (Priorities_Mapping);
 195    --  Suppress initialization in case gnat.adc specifies Normalize_Scalars
 196
 197    Underlying_Priorities : constant Priorities_Mapping :=
 198
 199      (Priority'First => 16,
 200
 201       1  => 17,
 202       2  => 18,
 203       3  => 18,
 204       4  => 18,
 205       5  => 18,
 206       6  => 19,
 207       7  => 19,
 208       8  => 19,
 209       9  => 20,
 210       10 => 20,
 211       11 => 21,
 212       12 => 21,
 213       13 => 22,
 214       14 => 23,
 215
 216       Default_Priority   => 24,
 217
 218       16 => 25,
 219       17 => 25,
 220       18 => 25,
 221       19 => 26,
 222       20 => 26,
 223       21 => 26,
 224       22 => 27,
 225       23 => 27,
 226       24 => 27,
 227       25 => 28,
 228       26 => 28,
 229       27 => 29,
 230       28 => 29,
 231       29 => 30,
 232
 233       Priority'Last      => 30,
 234
 235       Interrupt_Priority => 31);
 236
 237    ----------------------------
 238    -- Special VMS Interfaces --
 239    ----------------------------
 240
 241    procedure Lib_Stop (Cond_Value : Integer);
 242    pragma Import (C, Lib_Stop);
 243    pragma Import_Procedure (Lib_Stop, "LIB$STOP", Mechanism => (Value));
 244    --  Interface to VMS condition handling. Used by RTSfind and pragma
 245    --  {Import,Export}_Exception. Put here because this is the only
 246    --  VMS specific package that doesn't drag in tasking.
 247
 248    ADA_GNAT : constant Boolean := True;
 249    pragma Export_Object (ADA_GNAT, "ADA$GNAT");
 250    --  Ubiquitous global symbol identifying a GNAT compiled image to VMS Debug.
 251    --  Do not remove!
 252
 253    pragma Ident ("GNAT"); --  Gnat_Static_Version_String
 254    --  Default ident for all VMS images.
 255
 256 end System;