summaryrefslogtreecommitdiff
path: root/gcc/ada/system.ads
blob: 90b32878709fceba6cdbb63cddc2f9e0a0c7bd49 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
------------------------------------------------------------------------------
--                                                                          --
--                        GNAT RUN-TIME COMPONENTS                          --
--                                                                          --
--                               S Y S T E M                                --
--                                                                          --
--                                 S p e c                                  --
--                            (Compiler Version)                            --
--                                                                          --
--          Copyright (C) 1992-2009, Free Software Foundation, Inc.         --
--                                                                          --
-- This specification is derived from the Ada Reference Manual for use with --
-- GNAT. The copyright notice above, and the license provisions that follow --
-- apply solely to the  contents of the part following the private keyword. --
--                                                                          --
-- GNAT is free software;  you can  redistribute it  and/or modify it under --
-- terms of the  GNU General Public License as published  by the Free Soft- --
-- ware  Foundation;  either version 3,  or (at your option) any later ver- --
-- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
-- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
-- or FITNESS FOR A PARTICULAR PURPOSE.                                     --
--                                                                          --
-- As a special exception under Section 7 of GPL version 3, you are granted --
-- additional permissions described in the GCC Runtime Library Exception,   --
-- version 3.1, as published by the Free Software Foundation.               --
--                                                                          --
-- You should have received a copy of the GNU General Public License and    --
-- a copy of the GCC Runtime Library Exception along with this program;     --
-- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
-- <http://www.gnu.org/licenses/>.                                          --
--                                                                          --
-- GNAT was originally developed  by the GNAT team at  New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc.      --
--                                                                          --
------------------------------------------------------------------------------

--  This version of System is a generic version that is used in building the
--  compiler. Right now, we have a host/target problem if we try to use the
--  "proper" System, and since the compiler itself does not care about most
--  System parameters, this generic version works fine.

pragma Restrictions (No_Implicit_Dynamic_Code);
--  We want to avoid trampolines in the compiler, so it can be used in systems
--  which prevent execution of code on the stack, e.g. in windows environments
--  with DEP (Data Execution Protection) enabled.

package System is
   pragma Pure;
   --  Note that we take advantage of the implementation permission to make
   --  this unit Pure instead of Preelaborable; see RM 13.7.1(15). In Ada
   --  2005, this is Pure in any case (AI-362).

   type Name is (SYSTEM_NAME_GNAT);
   System_Name : constant Name := SYSTEM_NAME_GNAT;

   --  System-Dependent Named Numbers

   Min_Int               : constant := Long_Long_Integer'First;
   Max_Int               : constant := Long_Long_Integer'Last;

   Max_Binary_Modulus    : constant := 2 ** Long_Long_Integer'Size;
   Max_Nonbinary_Modulus : constant := 2 ** Integer'Size - 1;

   Max_Base_Digits       : constant := Long_Long_Float'Digits;
   Max_Digits            : constant := Long_Long_Float'Digits;

   Max_Mantissa          : constant := 63;
   Fine_Delta            : constant := 2.0 ** (-Max_Mantissa);

   Tick                  : constant := 0.01;

   --  Storage-related Declarations

   type Address is private;
   --  Note that we do NOT add pragma Preelaborable_Initialization in this
   --  version of System, since it is used for the compiler only, and typical
   --  earlier bootstrap compilers don't support this pragma. We don't need
   --  it in this context, so there is no problem in omitting it.
   Null_Address : constant Address;

   Storage_Unit : constant := Standard'Storage_Unit;
   Word_Size    : constant := Standard'Word_Size;
   Memory_Size  : constant := 2 ** Standard'Address_Size;

   --  Address comparison

   function "<"  (Left, Right : Address) return Boolean;
   function "<=" (Left, Right : Address) return Boolean;
   function ">"  (Left, Right : Address) return Boolean;
   function ">=" (Left, Right : Address) return Boolean;
   function "="  (Left, Right : Address) return Boolean;

   pragma Import (Intrinsic, "<");
   pragma Import (Intrinsic, "<=");
   pragma Import (Intrinsic, ">");
   pragma Import (Intrinsic, ">=");
   pragma Import (Intrinsic, "=");

   --  Other System-Dependent Declarations

   type Bit_Order is (High_Order_First, Low_Order_First);
   Default_Bit_Order : constant Bit_Order :=
                         Bit_Order'Val (Standard'Default_Bit_Order);
   pragma Warnings (Off, Default_Bit_Order); -- kill constant condition warning

   --  Priority-related Declarations (RM D.1)

   Max_Priority           : constant Positive := 30;
   Max_Interrupt_Priority : constant Positive := 31;

   subtype Any_Priority       is Integer      range  0 .. 31;
   subtype Priority           is Any_Priority range  0 .. 30;
   subtype Interrupt_Priority is Any_Priority range 31 .. 31;

   Default_Priority : constant Priority := 15;

private

   type Address is mod Memory_Size;
   Null_Address : constant Address := 0;

   --------------------------------------
   -- System Implementation Parameters --
   --------------------------------------

   --  These parameters provide information about the target that is used
   --  by the compiler. They are in the private part of System, where they
   --  can be accessed using the special circuitry in the Targparm unit
   --  whose source should be consulted for more detailed descriptions
   --  of the individual switch values.

   --  This version of system.ads is used only for building the compiler.
   --  We really ought to use the proper target system (i.e. the one that
   --  corresponds to the host for the compiler), but that causes as yet
   --  unsolved makefile problems. For the most part the setting of these
   --  parameters is not too critical for the compiler version (e.g. we
   --  do not use floating-point anyway in the compiler).

   AAMP                      : constant Boolean := False;
   Backend_Divide_Checks     : constant Boolean := False;
   Backend_Overflow_Checks   : constant Boolean := False;
   Command_Line_Args         : constant Boolean := True;
   Configurable_Run_Time     : constant Boolean := False;
   Denorm                    : constant Boolean := True;
   Duration_32_Bits          : constant Boolean := False;
   Exit_Status_Supported     : constant Boolean := True;
   Fractional_Fixed_Ops      : constant Boolean := False;
   Frontend_Layout           : constant Boolean := False;
   Machine_Overflows         : constant Boolean := False;
   Machine_Rounds            : constant Boolean := True;
   OpenVMS                   : constant Boolean := False;
   Preallocated_Stacks       : constant Boolean := False;
   Signed_Zeros              : constant Boolean := True;
   Stack_Check_Default       : constant Boolean := False;
   Stack_Check_Probes        : constant Boolean := False;
   Stack_Check_Limits        : constant Boolean := False;
   Support_64_Bit_Divides    : constant Boolean := True;
   Support_Aggregates        : constant Boolean := True;
   Support_Composite_Assign  : constant Boolean := True;
   Support_Composite_Compare : constant Boolean := True;
   Support_Long_Shifts       : constant Boolean := True;
   Always_Compatible_Rep     : constant Boolean := True;
   Suppress_Standard_Library : constant Boolean := False;
   Use_Ada_Main_Program_Name : constant Boolean := False;
   ZCX_By_Default            : constant Boolean := False;
   GCC_ZCX_Support           : constant Boolean := False;

   --  Obsolete entries, to be removed eventually (bootstrap issues!)

   Front_End_ZCX_Support     : constant Boolean := False;
   High_Integrity_Mode       : constant Boolean := False;
   Long_Shifts_Inlined       : constant Boolean := True;
   Functions_Return_By_DSP   : constant Boolean := False;

end System;