gcc/ada/libgnat/system-rtems.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) 1992-2024, 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 --  This version is for RTEMS.  It is based as closely as possible on the
  38 --  generic version with the following exceptions:
  39 --      + priority definitions
  40
  41 package System is
  42    pragma Pure;
  43    --  Note that we take advantage of the implementation permission to make
  44    --  this unit Pure instead of Preelaborable; see RM 13.7.1(15). In Ada
  45    --  2005, this is Pure in any case (AI-362).
  46
  47    pragma No_Elaboration_Code_All;
  48    --  Allow the use of that restriction in units that WITH this unit
  49
  50    type Name is (SYSTEM_NAME_GNAT);
  51    System_Name : constant Name := SYSTEM_NAME_GNAT;
  52
  53    --  System-Dependent Named Numbers
  54
  55    Min_Int             : constant := -2 ** (Standard'Max_Integer_Size - 1);
  56    Max_Int             : constant :=  2 ** (Standard'Max_Integer_Size - 1) - 1;
  57
  58    Max_Binary_Modulus    : constant := 2 ** Standard'Max_Integer_Size;
  59    Max_Nonbinary_Modulus : constant := 2 ** Integer'Size - 1;
  60
  61    Max_Base_Digits       : constant := Long_Long_Float'Digits;
  62    Max_Digits            : constant := Long_Long_Float'Digits;
  63
  64    Max_Mantissa          : constant := Standard'Max_Integer_Size - 1;
  65    Fine_Delta            : constant := 2.0 ** (-Max_Mantissa);
  66
  67    Tick                  : constant := 0.01;
  68
  69    --  Storage-related Declarations
  70
  71    type Address is private;
  72    pragma Preelaborable_Initialization (Address);
  73    Null_Address : constant Address;
  74
  75    Storage_Unit : constant := Standard'Storage_Unit;
  76    Word_Size    : constant := Standard'Word_Size;
  77    Memory_Size  : constant := 2 ** Standard'Address_Size;
  78
  79    --  Address comparison
  80
  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    function "="  (Left, Right : Address) return Boolean;
  86
  87    pragma Import (Intrinsic, "<");
  88    pragma Import (Intrinsic, "<=");
  89    pragma Import (Intrinsic, ">");
  90    pragma Import (Intrinsic, ">=");
  91    pragma Import (Intrinsic, "=");
  92
  93    --  Other System-Dependent Declarations
  94
  95    type Bit_Order is (High_Order_First, Low_Order_First);
  96    Default_Bit_Order : constant Bit_Order :=
  97                          Bit_Order'Val (Standard'Default_Bit_Order);
  98    pragma Warnings (Off, Default_Bit_Order); -- kill constant condition warning
  99
 100    --  Priority-related Declarations (RM D.1)
 101
 102    --  RTEMS POSIX threads support 256 priority levels with 255 being
 103    --  logically the most important. Levels 0 and 255 are reserved.
 104    --
 105    --  255        is reserved for RTEMS system tasks
 106    --  247 - 254  correspond to hardware interrupt levels 0 .. 7
 107    --  246        is a catchall default "interrupt" priority for signals,
 108    --             allowing higher priority than normal tasks, but lower than
 109    --             hardware priority levels.  Protected Object ceilings can
 110    --             override these values.
 111    --  245        is used by the Interrupt_Manager task
 112    --  0          is reserved for the RTEMS IDLE task
 113
 114    Max_Priority           : constant Positive := 244;
 115    Max_Interrupt_Priority : constant Positive := 254;
 116
 117    subtype Any_Priority       is Integer      range   1 .. 254;
 118    subtype Priority           is Any_Priority range   1 .. 244;
 119    subtype Interrupt_Priority is Any_Priority range 245 .. 254;
 120
 121    Default_Priority : constant Priority := 122;
 122
 123 private
 124
 125    type Address is mod Memory_Size;
 126    for Address'Size use Standard'Address_Size;
 127
 128    Null_Address : constant Address := 0;
 129
 130    --------------------------------------
 131    -- System Implementation Parameters --
 132    --------------------------------------
 133
 134    --  These parameters provide information about the target that is used
 135    --  by the compiler. They are in the private part of System, where they
 136    --  can be accessed using the special circuitry in the Targparm unit
 137    --  whose source should be consulted for more detailed descriptions
 138    --  of the individual switch values.
 139
 140    Backend_Divide_Checks     : constant Boolean := False;
 141    Backend_Overflow_Checks   : constant Boolean := True;
 142    Command_Line_Args         : constant Boolean := True;
 143    Configurable_Run_Time     : constant Boolean := False;
 144    Denorm                    : constant Boolean := True;
 145    Duration_32_Bits          : constant Boolean := False;
 146    Exit_Status_Supported     : constant Boolean := True;
 147    Machine_Overflows         : constant Boolean := False;
 148    Machine_Rounds            : constant Boolean := True;
 149    Preallocated_Stacks       : constant Boolean := False;
 150    Signed_Zeros              : constant Boolean := True;
 151    Stack_Check_Default       : constant Boolean := False;
 152    Stack_Check_Probes        : constant Boolean := False;
 153    Stack_Check_Limits        : constant Boolean := False;
 154    Support_Aggregates        : constant Boolean := True;
 155    Support_Atomic_Primitives : constant Boolean := True;
 156    Support_Composite_Assign  : constant Boolean := True;
 157    Support_Composite_Compare : constant Boolean := True;
 158    Support_Long_Shifts       : constant Boolean := True;
 159    Always_Compatible_Rep     : constant Boolean := False;
 160    Suppress_Standard_Library : constant Boolean := False;
 161    Use_Ada_Main_Program_Name : constant Boolean := False;
 162    ZCX_By_Default            : constant Boolean := True;
 163
 164 end System;