File : system-c.ads
1 ------------------------------------------------------------------------------
2 -- --
3 -- GNAT RUN-TIME COMPONENTS --
4 -- --
5 -- S Y S T E M --
6 -- --
7 -- S p e c --
8 -- (Generic C Version) --
9 -- --
10 -- Copyright (C) 1992-2015, 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 -- --
24 -- --
25 -- --
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 of System is a generic version suitable for use with a target
38 -- configuration file (-gnateT switch), for generating C code.
39
40 pragma Restrictions (No_Exception_Registration);
41 -- Disable exception name registration. This capability is not used because
42 -- it is only required by exception stream attributes which are not supported
43 -- in this run time.
44
45 pragma Restrictions (No_Implicit_Dynamic_Code);
46 -- Pointers to nested subprograms are not allowed in this run time, in order
47 -- to prevent the compiler from building "trampolines".
48
49 pragma Restrictions (No_Finalization);
50 -- Controlled types are not supported in this run time
51
52 pragma Restrictions (No_Tasking);
53 -- Tasking is not supported in this run time
54
55 pragma Restrictions (No_Task_Hierarchy);
56 -- Disable masters
57
58 pragma Restrictions (No_Abort_Statements);
59 pragma Restrictions (Max_Asynchronous_Select_Nesting => 0);
60 -- Disable abort deferral
61
62 pragma Restrictions (No_Dispatch);
63 -- Dispatching is not supported
64
65 pragma Restrictions (No_Streams);
66 -- Streams are not supported
67
68 pragma Restrictions (No_Secondary_Stack);
69 -- The secondary stack mechanism is not supported
70
71 pragma Restrictions (No_Initialize_Scalars);
72 -- To simplify the generated code
73
74 package System is
75 pragma Pure;
76 pragma No_Elaboration_Code_All;
77 -- Allow the use of that restriction in units that WITH this unit
78
79 type Name is (SYSTEM_NAME_GNAT);
80 System_Name : constant Name := SYSTEM_NAME_GNAT;
81
82 -- System-Dependent Named Numbers
83
84 Min_Int : constant := Long_Long_Integer'First;
85 Max_Int : constant := Long_Long_Integer'Last;
86
87 Max_Binary_Modulus : constant := 2 ** Long_Long_Integer'Size;
88 Max_Nonbinary_Modulus : constant := 2 ** Integer'Size - 1;
89
90 Max_Base_Digits : constant := Long_Long_Float'Digits;
91 Max_Digits : constant := Long_Long_Float'Digits;
92
93 Max_Mantissa : constant := 63;
94 Fine_Delta : constant := 2.0 ** (-Max_Mantissa);
95
96 Tick : constant := 0.01;
97
98 -- Storage-related Declarations
99
100 type Address is private;
101 pragma Preelaborable_Initialization (Address);
102
103 Null_Address : constant Address;
104
105 Storage_Unit : constant := Standard'Storage_Unit;
106 Word_Size : constant := Standard'Word_Size;
107 Memory_Size : constant := 2 ** Standard'Address_Size;
108
109 -- Address comparison
110
111 function "<" (Left, Right : Address) return Boolean;
112 function "<=" (Left, Right : Address) return Boolean;
113 function ">" (Left, Right : Address) return Boolean;
114 function ">=" (Left, Right : Address) return Boolean;
115 function "=" (Left, Right : Address) return Boolean;
116
117 pragma Import (Intrinsic, "<");
118 pragma Import (Intrinsic, "<=");
119 pragma Import (Intrinsic, ">");
120 pragma Import (Intrinsic, ">=");
121 pragma Import (Intrinsic, "=");
122
123 -- Other System-Dependent Declarations
124
125 type Bit_Order is (High_Order_First, Low_Order_First);
126 Default_Bit_Order : constant Bit_Order :=
127 Bit_Order'Val (Standard'Default_Bit_Order);
128 pragma Warnings (Off, Default_Bit_Order); -- kill constant condition warning
129
130 -- Priority-related Declarations (RM D.1)
131
132 Max_Priority : constant Positive := 30;
133 Max_Interrupt_Priority : constant Positive := 31;
134
135 subtype Any_Priority is Integer range 0 .. 31;
136 subtype Priority is Any_Priority range 0 .. 30;
137 subtype Interrupt_Priority is Any_Priority range 31 .. 31;
138
139 Default_Priority : constant Priority := 15;
140
141 private
142
143 type Address is mod Memory_Size;
144 Null_Address : constant Address := 0;
145
146 --------------------------------------
147 -- System Implementation Parameters --
148 --------------------------------------
149
150 -- These parameters provide information about the target that is used
151 -- by the compiler. They are in the private part of System, where they
152 -- can be accessed using the special circuitry in the Targparm unit
153 -- whose source should be consulted for more detailed descriptions
154 -- of the individual switch values.
155
156 Backend_Divide_Checks : constant Boolean := False;
157 Backend_Overflow_Checks : constant Boolean := True;
158 Command_Line_Args : constant Boolean := False;
159 Configurable_Run_Time : constant Boolean := True;
160 Denorm : constant Boolean := True;
161 Duration_32_Bits : constant Boolean := True;
162 Exit_Status_Supported : constant Boolean := False;
163 Fractional_Fixed_Ops : constant Boolean := False;
164 Frontend_Layout : constant Boolean := False;
165 Machine_Overflows : constant Boolean := False;
166 Machine_Rounds : constant Boolean := True;
167 Preallocated_Stacks : constant Boolean := False;
168 Signed_Zeros : constant Boolean := True;
169 Stack_Check_Default : constant Boolean := False;
170 Stack_Check_Probes : constant Boolean := False;
171 Stack_Check_Limits : constant Boolean := False;
172 Support_Aggregates : constant Boolean := True;
173 Support_Composite_Assign : constant Boolean := True;
174 Support_Composite_Compare : constant Boolean := True;
175 Support_Long_Shifts : constant Boolean := True;
176 Always_Compatible_Rep : constant Boolean := True;
177 Suppress_Standard_Library : constant Boolean := True;
178 Use_Ada_Main_Program_Name : constant Boolean := False;
179 Frontend_Exceptions : constant Boolean := True;
180 ZCX_By_Default : constant Boolean := False;
181
182 end System;