[thirdparty/gcc.git] / gcc / ada / libgnat / system.ads

------------------------------------------------------------------------------
--                                                                          --
--                        GNAT RUN-TIME COMPONENTS                          --
--                                                                          --
--                               S Y S T E M                                --
--                                                                          --
--                                 S p e c                                  --
--                            (Compiler Version)                            --
--                                                                          --
--          Copyright (C) 1992-2020, 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.

pragma Restrictions (No_Finalization);
--  Use restriction No_Finalization to avoid pulling finalization (not allowed
--  in GNAT) inside sem_spark.adb, when defining type Perm_Tree_Access as an
--  access type on incomplete type Perm_Tree_Wrapper (which is required for
--  defining a recursive type).

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).

   pragma No_Elaboration_Code_All;
   --  Allow the use of that restriction in units that WITH this unit

   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;
   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_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;
   Frontend_Exceptions       : constant Boolean := False;
   ZCX_By_Default            : constant Boolean := True;

   --  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;
   Support_64_Bit_Divides    : constant Boolean := True;
   GCC_ZCX_Support           : constant Boolean := True;

end System;
Commit	Line	Data
9d19cb95 RK	1	------------------------------------------------------------------------------
	2	-- --
	3	-- GNAT RUN-TIME COMPONENTS --
	4	-- --
	5	-- S Y S T E M --
	6	-- --
	7	-- S p e c --
fbf5a39b	8	-- (Compiler Version) --
9d19cb95	9	-- --
4b490c1e	10	-- Copyright (C) 1992-2020, Free Software Foundation, Inc. --
9d19cb95 RK	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- --
748086b7	18	-- ware Foundation; either version 3, or (at your option) any later ver- --
9d19cb95 RK	19	-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
9d19cb95 RK	20	-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
748086b7 JJ	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/>. --
9d19cb95 RK	31	-- --
9d19cb95 RK	32	-- GNAT was originally developed by the GNAT team at New York University. --
71ff80dc	33	-- Extensive contributions were provided by Ada Core Technologies Inc. --
9d19cb95 RK	34	-- --
	35	------------------------------------------------------------------------------
	36
0312b364 EB	37	-- This version of System is a generic version that is used in building the
	38	-- compiler. Right now, we have a host/target problem if we try to use the
	39	-- "proper" System, and since the compiler itself does not care about most
	40	-- System parameters, this generic version works fine.
	41
	42	pragma Restrictions (No_Implicit_Dynamic_Code);
	43	-- We want to avoid trampolines in the compiler, so it can be used in systems
	44	-- which prevent execution of code on the stack, e.g. in windows environments
	45	-- with DEP (Data Execution Protection) enabled.
07fc65c4	46
fb69239a AC	47	pragma Restrictions (No_Finalization);
	48	-- Use restriction No_Finalization to avoid pulling finalization (not allowed
	49	-- in GNAT) inside sem_spark.adb, when defining type Perm_Tree_Access as an
	50	-- access type on incomplete type Perm_Tree_Wrapper (which is required for
	51	-- defining a recursive type).
	52
9d19cb95	53	package System is
009186e0 AC	54	pragma Pure;
	55	-- Note that we take advantage of the implementation permission to make
	56	-- this unit Pure instead of Preelaborable; see RM 13.7.1(15). In Ada
	57	-- 2005, this is Pure in any case (AI-362).
9d19cb95	58
cd2c6027 AC	59	pragma No_Elaboration_Code_All;
	60	-- Allow the use of that restriction in units that WITH this unit
	61
9d19cb95 RK	62	type Name is (SYSTEM_NAME_GNAT);
	63	System_Name : constant Name := SYSTEM_NAME_GNAT;
	64
	65	-- System-Dependent Named Numbers
	66
	67	Min_Int : constant := Long_Long_Integer'First;
	68	Max_Int : constant := Long_Long_Integer'Last;
	69
	70	Max_Binary_Modulus : constant := 2 ** Long_Long_Integer'Size;
a538d226	71	Max_Nonbinary_Modulus : constant := 2 ** Integer'Size - 1;
9d19cb95 RK	72
	73	Max_Base_Digits : constant := Long_Long_Float'Digits;
	74	Max_Digits : constant := Long_Long_Float'Digits;
	75
	76	Max_Mantissa : constant := 63;
	77	Fine_Delta : constant := 2.0 ** (-Max_Mantissa);
	78
fbf5a39b	79	Tick : constant := 0.01;
9d19cb95 RK	80
	81	-- Storage-related Declarations
	82
	83	type Address is private;
a538d226 AC	84	-- Note that we do NOT add pragma Preelaborable_Initialization in this
	85	-- version of System, since it is used for the compiler only, and typical
	86	-- earlier bootstrap compilers don't support this pragma. We don't need
	87	-- it in this context, so there is no problem in omitting it.
9d19cb95 RK	88	Null_Address : constant Address;
	89
	90	Storage_Unit : constant := Standard'Storage_Unit;
	91	Word_Size : constant := Standard'Word_Size;
	92	Memory_Size : constant := 2 ** Standard'Address_Size;
	93
	94	-- Address comparison
	95
	96	function "<" (Left, Right : Address) return Boolean;
	97	function "<=" (Left, Right : Address) return Boolean;
	98	function ">" (Left, Right : Address) return Boolean;
	99	function ">=" (Left, Right : Address) return Boolean;
	100	function "=" (Left, Right : Address) return Boolean;
	101
	102	pragma Import (Intrinsic, "<");
	103	pragma Import (Intrinsic, "<=");
	104	pragma Import (Intrinsic, ">");
	105	pragma Import (Intrinsic, ">=");
	106	pragma Import (Intrinsic, "=");
	107
	108	-- Other System-Dependent Declarations
	109
	110	type Bit_Order is (High_Order_First, Low_Order_First);
	111	Default_Bit_Order : constant Bit_Order :=
	112	Bit_Order'Val (Standard'Default_Bit_Order);
f28ded01	113	pragma Warnings (Off, Default_Bit_Order); -- kill constant condition warning
9d19cb95 RK	114
	115	-- Priority-related Declarations (RM D.1)
	116
07fc65c4	117	Max_Priority : constant Positive := 30;
9d19cb95 RK	118	Max_Interrupt_Priority : constant Positive := 31;
9d19cb95 RK	119
07fc65c4 GB	120	subtype Any_Priority is Integer range 0 .. 31;
	121	subtype Priority is Any_Priority range 0 .. 30;
	122	subtype Interrupt_Priority is Any_Priority range 31 .. 31;
9d19cb95	123
07fc65c4	124	Default_Priority : constant Priority := 15;
9d19cb95 RK	125
	126	private
	127
	128	type Address is mod Memory_Size;
	129	Null_Address : constant Address := 0;
	130
	131	--------------------------------------
	132	-- System Implementation Parameters --
	133	--------------------------------------
	134
0bfc9a64 AC	135	-- These parameters provide information about the target that is used by
	136	-- the compiler. They are in the private part of System, where they can be
	137	-- accessed using the special circuitry in the Targparm unit whose source
	138	-- should be consulted for more detailed descriptions of the individual
	139	-- switch values.
9d19cb95 RK	140
	141	-- This version of system.ads is used only for building the compiler.
	142	-- We really ought to use the proper target system (i.e. the one that
	143	-- corresponds to the host for the compiler), but that causes as yet
	144	-- unsolved makefile problems. For the most part the setting of these
	145	-- parameters is not too critical for the compiler version (e.g. we
	146	-- do not use floating-point anyway in the compiler).
	147
	148	AAMP : constant Boolean := False;
07fc65c4 GB	149	Backend_Divide_Checks : constant Boolean := False;
07fc65c4 GB	150	Backend_Overflow_Checks : constant Boolean := False;
9d19cb95	151	Command_Line_Args : constant Boolean := True;
fbf5a39b	152	Configurable_Run_Time : constant Boolean := False;
9d19cb95	153	Denorm : constant Boolean := True;
fbf5a39b AC	154	Duration_32_Bits : constant Boolean := False;
fbf5a39b AC	155	Exit_Status_Supported : constant Boolean := True;
07fc65c4	156	Fractional_Fixed_Ops : constant Boolean := False;
9d19cb95	157	Frontend_Layout : constant Boolean := False;
9d19cb95 RK	158	Machine_Overflows : constant Boolean := False;
9d19cb95 RK	159	Machine_Rounds : constant Boolean := True;
b23e28d5	160	Preallocated_Stacks : constant Boolean := False;
9d19cb95 RK	161	Signed_Zeros : constant Boolean := True;
	162	Stack_Check_Default : constant Boolean := False;
	163	Stack_Check_Probes : constant Boolean := False;
0312b364	164	Stack_Check_Limits : constant Boolean := False;
fbf5a39b AC	165	Support_Aggregates : constant Boolean := True;
	166	Support_Composite_Assign : constant Boolean := True;
	167	Support_Composite_Compare : constant Boolean := True;
	168	Support_Long_Shifts : constant Boolean := True;
0312b364	169	Always_Compatible_Rep : constant Boolean := True;
fbf5a39b	170	Suppress_Standard_Library : constant Boolean := False;
9d19cb95	171	Use_Ada_Main_Program_Name : constant Boolean := False;
6cbfce7e AC	172	Frontend_Exceptions : constant Boolean := False;
6cbfce7e AC	173	ZCX_By_Default : constant Boolean := True;
9d19cb95	174
a90bd866	175	-- Obsolete entries, to be removed eventually (bootstrap issues)
fbf5a39b	176
a538d226	177	Front_End_ZCX_Support : constant Boolean := False;
fbf5a39b AC	178	High_Integrity_Mode : constant Boolean := False;
fbf5a39b AC	179	Long_Shifts_Inlined : constant Boolean := True;
0903be23	180	Functions_Return_By_DSP : constant Boolean := False;
5cd7bb15	181	Support_64_Bit_Divides : constant Boolean := True;
6cbfce7e	182	GCC_ZCX_Support : constant Boolean := True;
fbf5a39b	183
9d19cb95	184	end System;