gcc/ada/system-vms.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                        GNAT RUN-TIME COMPONENTS                          --
   4 --                                                                          --
   5 --                               S Y S T E M                                --
   6 --                                                                          --
   7 --                                 S p e c                                  --
   8 --                       (OpenVMS DEC Threads Version)                      --
   9 --                                                                          --
  10 --          Copyright (C) 1992-2006, 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 2,  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.  See the GNU General Public License --
  22 -- for  more details.  You should have  received  a copy of the GNU General --
  23 -- Public License  distributed with GNAT;  see file COPYING.  If not, write --
  24 -- to  the  Free Software Foundation,  51  Franklin  Street,  Fifth  Floor, --
  25 -- Boston, MA 02110-1301, USA.                                              --
  26 --                                                                          --
  27 -- As a special exception,  if other files  instantiate  generics from this --
  28 -- unit, or you link  this unit with other files  to produce an executable, --
  29 -- this  unit  does not  by itself cause  the resulting  executable  to  be --
  30 -- covered  by the  GNU  General  Public  License.  This exception does not --
  31 -- however invalidate  any other reasons why  the executable file  might be --
  32 -- covered by the  GNU Public License.                                      --
  33 --                                                                          --
  34 -- GNAT was originally developed  by the GNAT team at  New York University. --
  35 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  36 --                                                                          --
  37 ------------------------------------------------------------------------------
  38
  39 package System is
  40    pragma Pure;
  41    --  Note that we take advantage of the implementation permission to make
  42    --  this unit Pure instead of Preelaborable; see RM 13.7.1(15). In Ada
  43    --  2005, this is Pure in any case (AI-362).
  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 := 0.01;
  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    Compiler_System_Version   : constant Boolean := False;
 123    Configurable_Run_Time     : constant Boolean := False;
 124    Denorm                    : constant Boolean := False;
 125    Duration_32_Bits          : constant Boolean := False;
 126    Exit_Status_Supported     : constant Boolean := True;
 127    Fractional_Fixed_Ops      : constant Boolean := False;
 128    Frontend_Layout           : constant Boolean := False;
 129    Functions_Return_By_DSP   : constant Boolean := False;
 130    Machine_Overflows         : constant Boolean := False;
 131    Machine_Rounds            : constant Boolean := True;
 132    OpenVMS                   : constant Boolean := True;
 133    Preallocated_Stacks       : constant Boolean := False;
 134    Signed_Zeros              : constant Boolean := True;
 135    Stack_Check_Default       : constant Boolean := True;
 136    Stack_Check_Probes        : constant Boolean := True;
 137    Support_64_Bit_Divides    : constant Boolean := True;
 138    Support_Aggregates        : 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    Suppress_Standard_Library : constant Boolean := False;
 143    Use_Ada_Main_Program_Name : constant Boolean := False;
 144    ZCX_By_Default            : constant Boolean := True;
 145    GCC_ZCX_Support           : constant Boolean := False;
 146    Front_End_ZCX_Support     : constant Boolean := True;
 147
 148    --  Obsolete entries, to be removed eventually (bootstrap issues!)
 149
 150    High_Integrity_Mode       : constant Boolean := False;
 151    Long_Shifts_Inlined       : constant Boolean := False;
 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 Threads OpenVMS, we use the full range of 31 priorities
 167    --  in the Ada model, but map them by compression onto the more limited
 168    --  range of priorities available in OpenVMS.
 169
 170    --  To replace the default values of the Underlying_Priorities mapping,
 171    --  copy this source file into your build directory, edit the file to
 172    --  reflect your desired behavior, and recompile with the command:
 173
 174    --     $ gcc -c -O3 -gnatpgn system.ads
 175
 176    --  then recompile the run-time parts that depend on this package:
 177
 178    --     $ gnatmake -a -gnatn -O3 <your application>
 179
 180    --  then force rebuilding your application if you need different options:
 181
 182    --     $ gnatmake -f <your options> <your application>
 183
 184    type Priorities_Mapping is array (Any_Priority) of Integer;
 185    pragma Suppress_Initialization (Priorities_Mapping);
 186    --  Suppress initialization in case gnat.adc specifies Normalize_Scalars
 187
 188    Underlying_Priorities : constant Priorities_Mapping :=
 189
 190      (Priority'First => 16,
 191
 192       1  => 17,
 193       2  => 18,
 194       3  => 18,
 195       4  => 18,
 196       5  => 18,
 197       6  => 19,
 198       7  => 19,
 199       8  => 19,
 200       9  => 20,
 201       10 => 20,
 202       11 => 21,
 203       12 => 21,
 204       13 => 22,
 205       14 => 23,
 206
 207       Default_Priority   => 24,
 208
 209       16 => 25,
 210       17 => 25,
 211       18 => 25,
 212       19 => 26,
 213       20 => 26,
 214       21 => 26,
 215       22 => 27,
 216       23 => 27,
 217       24 => 27,
 218       25 => 28,
 219       26 => 28,
 220       27 => 29,
 221       28 => 29,
 222       29 => 30,
 223
 224       Priority'Last      => 30,
 225
 226       Interrupt_Priority => 31);
 227
 228    ----------------------------
 229    -- Special VMS Interfaces --
 230    ----------------------------
 231
 232    procedure Lib_Stop (I : Integer);
 233    pragma Interface (C, Lib_Stop);
 234    pragma Import_Procedure (Lib_Stop, "LIB$STOP", Mechanism => (Value));
 235    --  Interface to VMS condition handling. Used by RTSfind and pragma
 236    --  {Import,Export}_Exception. Put here because this is the only
 237    --  VMS specific package that doesn't drag in tasking.
 238
 239    ADA_GNAT : constant Boolean := True;
 240    pragma Export_Object (ADA_GNAT, "ADA$GNAT");
 241    --  Uniquitous global symbol identifing a GNAT compiled image to VMS Debug.
 242    --  Do not remove!
 243
 244 end System;