mirror of
https://git.FreeBSD.org/ports.git
synced 2024-10-29 21:39:24 +00:00
95df74e9ba
Thanks to Samuel Tardieu <sam@inf.enst.fr> for instigating this update and providing some of the changes.
243 lines
11 KiB
Ada
243 lines
11 KiB
Ada
------------------------------------------------------------------------------
|
|
-- --
|
|
-- GNAT RUN-TIME COMPONENTS --
|
|
-- --
|
|
-- S Y S T E M --
|
|
-- --
|
|
-- S p e c --
|
|
-- (Default Version) --
|
|
-- --
|
|
-- $Revision: 1.40 $
|
|
-- --
|
|
-- Copyright (C) 1992-2000 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 2, 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. See the GNU General Public License --
|
|
-- for more details. You should have received a copy of the GNU General --
|
|
-- Public License distributed with GNAT; see file COPYING. If not, write --
|
|
-- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
|
|
-- MA 02111-1307, USA. --
|
|
-- --
|
|
-- As a special exception, if other files instantiate generics from this --
|
|
-- unit, or you link this unit with other files to produce an executable, --
|
|
-- this unit does not by itself cause the resulting executable to be --
|
|
-- covered by the GNU General Public License. This exception does not --
|
|
-- however invalidate any other reasons why the executable file might be --
|
|
-- covered by the GNU Public License. --
|
|
-- --
|
|
-- GNAT was originally developed by the GNAT team at New York University. --
|
|
-- It is now maintained by Ada Core Technologies Inc (http://www.gnat.com). --
|
|
-- --
|
|
------------------------------------------------------------------------------
|
|
|
|
package System is
|
|
pragma Pure (System);
|
|
-- Note that we take advantage of the implementation permission to
|
|
-- make this unit Pure instead of Preelaborable, see RM 13.7(36)
|
|
|
|
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 := Integer'Last;
|
|
|
|
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 := Standard'Tick;
|
|
|
|
-- Storage-related Declarations
|
|
|
|
type Address is private;
|
|
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);
|
|
|
|
-- Priority-related Declarations (RM D.1)
|
|
|
|
Max_Priority : constant Positive := 30;
|
|
|
|
Max_Interrupt_Priority : constant Positive := 31;
|
|
|
|
subtype Any_Priority is Integer
|
|
range 0 .. Standard'Max_Interrupt_Priority;
|
|
|
|
subtype Priority is Any_Priority
|
|
range 0 .. Standard'Max_Priority;
|
|
|
|
-- Functional notation is needed in the following to avoid visibility
|
|
-- problems when this package is compiled through rtsfind in the middle
|
|
-- of another compilation.
|
|
|
|
subtype Interrupt_Priority is Any_Priority
|
|
range
|
|
Standard."+" (Standard'Max_Priority, 1) ..
|
|
Standard'Max_Interrupt_Priority;
|
|
|
|
Default_Priority : constant Priority :=
|
|
Standard."/" (Standard."+" (Priority'First, Priority'Last), 2);
|
|
|
|
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 Rtsfind. All values defined here must be
|
|
-- constants, since they are accessed at compile time.
|
|
|
|
-- Note these definitions must come before the definitions of any
|
|
-- complex types or other code that may require Rtsfind to access
|
|
-- these entities during compilation of System itself.
|
|
|
|
-----------------------------------
|
|
-- Control of Exception Handling --
|
|
-----------------------------------
|
|
|
|
-- GNAT provides two methods of implementing exceptions:
|
|
|
|
-- Longjmp/Setjmp (-gnatL)
|
|
|
|
-- This approach uses longjmp/setjmp to handle exceptions. It
|
|
-- uses less storage, and can often propagate exceptions faster,
|
|
-- at the expense of (sometimes considerable) overhead in setting
|
|
-- up an exception handler. This approach is available on all
|
|
-- targets, and is the default where it is the only approach.
|
|
|
|
-- Zero Cost (-gnatZ)
|
|
|
|
-- This approach uses separate exception tables. These use extra
|
|
-- storage, and exception propagation can be quite slow, but there
|
|
-- is no overhead in setting up an exception handler (it is to this
|
|
-- latter operation that the phrase zero-cost refers). This approach
|
|
-- is only available on some targets, and is the default where it is
|
|
-- available.
|
|
|
|
Zero_Cost_Exceptions : constant Boolean := False;
|
|
-- Set False for Longjmp/Setjmp, True for Zero Cost
|
|
|
|
-------------------------------
|
|
-- Control of Stack Checking --
|
|
-------------------------------
|
|
|
|
-- GNAT provides two methods of implementing exceptions:
|
|
|
|
-- GCC Probing Mechanism
|
|
|
|
-- This approach uses the standard GCC mechanism for
|
|
-- stack checking. The method assumes that accessing
|
|
-- storage immediately beyond the end of the stack
|
|
-- will result in a trap that is converted to a storage
|
|
-- error by the runtime system. This mechanism has
|
|
-- minimal overhead, but requires complex hardware,
|
|
-- operating system and run-time support. Probing is
|
|
-- the default method where it is available. The stack
|
|
-- size for the environment task depends on the operating
|
|
-- system and cannot be set in a system-independent way.
|
|
|
|
-- GNAT Stack-limit Checking
|
|
|
|
-- This method relies on comparing the stack pointer
|
|
-- with per-task stack limits. If the check fails, an
|
|
-- exception is explicitly raised. The advantage is
|
|
-- that the method requires no extra system dependent
|
|
-- runtime support and can be used on systems without
|
|
-- memory protection as well, but at the cost of more
|
|
-- overhead for doing the check. This method is the
|
|
-- default on systems that lack complete support for
|
|
-- probing.
|
|
|
|
Stack_Check_Probes : constant Boolean := True;
|
|
-- Set True for GCC Probing, False for GNAT Stack-limit Checking
|
|
|
|
Stack_Check_Default : constant Boolean := True;
|
|
-- Set True for systems where stack checking is performed by default
|
|
|
|
----------------------------------------------
|
|
-- Boolean-Valued Floating-Point Attributes --
|
|
----------------------------------------------
|
|
|
|
-- The constants below give the values for representation oriented
|
|
-- floating-point attributes that are the same for all float types
|
|
-- on the target. These are all boolean values.
|
|
|
|
-- A value is only True if the target reliably supports the corresponding
|
|
-- feature. Reliably here means that support is guaranteed for all
|
|
-- possible settings of the relevant compiler switches (like -mieee),
|
|
-- since we cannot control the user setting of those switches.
|
|
|
|
-- The attributes cannot dependent on the current setting of compiler
|
|
-- switches, since the values must be static and consistent throughout
|
|
-- the partition. We probably should add such consistency checks in future,
|
|
-- but for now we don't do this.
|
|
|
|
Denorm : constant Boolean := True;
|
|
|
|
Machine_Rounds : constant Boolean := True;
|
|
|
|
Machine_Overflows : constant Boolean := False;
|
|
|
|
Signed_Zeros : constant Boolean := True;
|
|
|
|
----------------------------
|
|
-- Support of Long Shifts --
|
|
----------------------------
|
|
|
|
-- In GNORT mode, we cannot call library routines, and in particular
|
|
-- we cannot call routines for long (64-bit) shifts if such routines
|
|
-- are required on the target. This comes up in the context of support
|
|
-- of packed arrays. We can only represent packed arrays whose length
|
|
-- is in the range 33- to 64-bits as modular types if long shifts are
|
|
-- done with inline code.
|
|
|
|
-- For the default version, for now we set long shifts inlined as True
|
|
-- This may not be quite accurate, but until we get proper separate
|
|
-- System's for each target, it is a safer choice.
|
|
|
|
Long_Shifts_Inlined : constant Boolean := True;
|
|
|
|
end System;
|