gcc/ada/system.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                        GNAT RUN-TIME COMPONENTS                          --
   4 --                                                                          --
   5 --                               S Y S T E M                                --
   6 --                                                                          --
   7 --                                 S p e c                                  --
   8 --                            (Compiler Version)                            --
   9 --                                                                          --
  10 --          Copyright (C) 1992-2007, 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 --  This version of System is a generic version that is used in building the
  40 --  compiler. Right now, we have a host/target problem if we try to use the
  41 --  "proper" System, and since the compiler itself does not care about most
  42 --  System parameters, this generic version works fine.
  43
  44 pragma Restrictions (No_Implicit_Dynamic_Code);
  45 --  We want to avoid trampolines in the compiler, so it can be used in systems
  46 --  which prevent execution of code on the stack, e.g. in windows environments
  47 --  with DEP (Data Execution Protection) enabled.
  48
  49 package System is
  50    pragma Pure;
  51    --  Note that we take advantage of the implementation permission to make
  52    --  this unit Pure instead of Preelaborable; see RM 13.7.1(15). In Ada
  53    --  2005, this is Pure in any case (AI-362).
  54
  55    type Name is (SYSTEM_NAME_GNAT);
  56    System_Name : constant Name := SYSTEM_NAME_GNAT;
  57
  58    --  System-Dependent Named Numbers
  59
  60    Min_Int               : constant := Long_Long_Integer'First;
  61    Max_Int               : constant := Long_Long_Integer'Last;
  62
  63    Max_Binary_Modulus    : constant := 2 ** Long_Long_Integer'Size;
  64    Max_Nonbinary_Modulus : constant := 2 ** Integer'Size - 1;
  65
  66    Max_Base_Digits       : constant := Long_Long_Float'Digits;
  67    Max_Digits            : constant := Long_Long_Float'Digits;
  68
  69    Max_Mantissa          : constant := 63;
  70    Fine_Delta            : constant := 2.0 ** (-Max_Mantissa);
  71
  72    Tick                  : constant := 0.01;
  73
  74    --  Storage-related Declarations
  75
  76    type Address is private;
  77    --  Note that we do NOT add pragma Preelaborable_Initialization in this
  78    --  version of System, since it is used for the compiler only, and typical
  79    --  earlier bootstrap compilers don't support this pragma. We don't need
  80    --  it in this context, so there is no problem in omitting it.
  81    Null_Address : constant Address;
  82
  83    Storage_Unit : constant := Standard'Storage_Unit;
  84    Word_Size    : constant := Standard'Word_Size;
  85    Memory_Size  : constant := 2 ** Standard'Address_Size;
  86
  87    --  Address comparison
  88
  89    function "<"  (Left, Right : Address) return Boolean;
  90    function "<=" (Left, Right : Address) return Boolean;
  91    function ">"  (Left, Right : Address) return Boolean;
  92    function ">=" (Left, Right : Address) return Boolean;
  93    function "="  (Left, Right : Address) return Boolean;
  94
  95    pragma Import (Intrinsic, "<");
  96    pragma Import (Intrinsic, "<=");
  97    pragma Import (Intrinsic, ">");
  98    pragma Import (Intrinsic, ">=");
  99    pragma Import (Intrinsic, "=");
 100
 101    --  Other System-Dependent Declarations
 102
 103    type Bit_Order is (High_Order_First, Low_Order_First);
 104    Default_Bit_Order : constant Bit_Order :=
 105                          Bit_Order'Val (Standard'Default_Bit_Order);
 106    pragma Warnings (Off, Default_Bit_Order); -- kill constant condition warning
 107
 108    --  Priority-related Declarations (RM D.1)
 109
 110    Max_Priority           : constant Positive := 30;
 111    Max_Interrupt_Priority : constant Positive := 31;
 112
 113    subtype Any_Priority       is Integer      range  0 .. 31;
 114    subtype Priority           is Any_Priority range  0 .. 30;
 115    subtype Interrupt_Priority is Any_Priority range 31 .. 31;
 116
 117    Default_Priority : constant Priority := 15;
 118
 119 private
 120
 121    type Address is mod Memory_Size;
 122    Null_Address : constant Address := 0;
 123
 124    --------------------------------------
 125    -- System Implementation Parameters --
 126    --------------------------------------
 127
 128    --  These parameters provide information about the target that is used
 129    --  by the compiler. They are in the private part of System, where they
 130    --  can be accessed using the special circuitry in the Targparm unit
 131    --  whose source should be consulted for more detailed descriptions
 132    --  of the individual switch values.
 133
 134    --  This version of system.ads is used only for building the compiler.
 135    --  We really ought to use the proper target system (i.e. the one that
 136    --  corresponds to the host for the compiler), but that causes as yet
 137    --  unsolved makefile problems. For the most part the setting of these
 138    --  parameters is not too critical for the compiler version (e.g. we
 139    --  do not use floating-point anyway in the compiler).
 140
 141    AAMP                      : constant Boolean := False;
 142    Backend_Divide_Checks     : constant Boolean := False;
 143    Backend_Overflow_Checks   : constant Boolean := False;
 144    Command_Line_Args         : constant Boolean := True;
 145    Configurable_Run_Time     : constant Boolean := False;
 146    Denorm                    : constant Boolean := True;
 147    Duration_32_Bits          : constant Boolean := False;
 148    Exit_Status_Supported     : constant Boolean := True;
 149    Fractional_Fixed_Ops      : constant Boolean := False;
 150    Frontend_Layout           : constant Boolean := False;
 151    Machine_Overflows         : constant Boolean := False;
 152    Machine_Rounds            : constant Boolean := True;
 153    OpenVMS                   : constant Boolean := False;
 154    Preallocated_Stacks       : constant Boolean := False;
 155    Signed_Zeros              : constant Boolean := True;
 156    Stack_Check_Default       : constant Boolean := False;
 157    Stack_Check_Probes        : constant Boolean := False;
 158    Stack_Check_Limits        : constant Boolean := False;
 159    Support_64_Bit_Divides    : constant Boolean := True;
 160    Support_Aggregates        : constant Boolean := True;
 161    Support_Composite_Assign  : constant Boolean := True;
 162    Support_Composite_Compare : constant Boolean := True;
 163    Support_Long_Shifts       : constant Boolean := True;
 164    Always_Compatible_Rep     : constant Boolean := True;
 165    Suppress_Standard_Library : constant Boolean := False;
 166    Use_Ada_Main_Program_Name : constant Boolean := False;
 167    ZCX_By_Default            : constant Boolean := False;
 168    GCC_ZCX_Support           : constant Boolean := False;
 169
 170    --  Obsolete entries, to be removed eventually (bootstrap issues!)
 171
 172    Front_End_ZCX_Support     : constant Boolean := False;
 173    High_Integrity_Mode       : constant Boolean := False;
 174    Long_Shifts_Inlined       : constant Boolean := True;
 175    Functions_Return_By_DSP   : constant Boolean := False;
 176
 177 end System;