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------------------------------------------------------------------------------
-- --
-- GNAT RUN-TIME COMPONENTS --
-- --
-- S Y S T E M . H I E _ B A C K _ E N D --
-- --
-- S p e c --
-- --
-- Copyright (C) 2001-2009, Free Software Foundation, Inc. --
-- --
-- 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 package provides an interface used in HI-E mode to determine
-- whether or not the back end can handle certain constructs in a manner
-- that is consistent with certification requirements.
-- The approach is to define entities which may or may not be present in
-- a HI-E configured library. If the entity is present then the compiler
-- operating in HI-E mode will allow the corresponding operation. If the
-- entity is not present, the corresponding construct will be flagged as
-- not permitted in High Integrity mode.
-- The default version of this unit delivered with the HI-E compiler is
-- configured in a manner appropriate for the target, but it is possible
-- to reconfigure the run-time to change the settings as required.
-- This unit is not used and never accessed by the compiler unless it is
-- operating in HI-E mode, so the settings are irrelevant. However, we
-- do include a standard version with all entities present in the standard
-- run-time for use when pragma No_Run_Time is specified.
package System.HIE_Back_End is
type Dummy is null record;
pragma Suppress_Initialization (Dummy);
-- This is the type used for the entities below. No properties of this
-- type are ever referenced, and in particular, the entities are defined
-- as variables, but their values are never referenced
HIE_64_Bit_Divides : Dummy;
-- This entity controls whether the front end allows 64-bit integer
-- divide operations, including the case where division of 32-bit
-- fixed-point operands requires 64-bit arithmetic. This can safely
-- be set as High_Integrity on 64-bit machines which provide this
-- operation as a native instruction, but on most 32-bit machines
-- a run time call (e.g. to __divdi3 in gcclib) is required. If a
-- certifiable version of this routine is available, then setting
-- this entity to High_Integrity with a pragma will cause appropriate
-- calls to be generated, allowing 64-bit integer division operations.
HIE_Long_Shifts : Dummy;
-- This entity controls whether the front end allows generation of
-- long shift instructions, i.e. shifts that operate on 64-bit values.
-- Such shifts are required for the implementation of fixed-point
-- types longer than 32 bits. This can safely be set as High_Integrity
-- on 64-bit machines that provide this operation at the hardware level,
-- but on some 32-bit machines a run time call is required. If there
-- is a certifiable version available of the relevant run-time routines,
-- then setting this entity to High_Integrity with a pragma will cause
-- appropriate calls to be generated, allowing the declaration and use
-- of fixed-point types longer than 32 bits.
HIE_Aggregates : Dummy;
-- In the general case, the use of aggregates may generate calls
-- to run-time routines in the C library, including memset, memcpy,
-- memmove, and bcopy. This entity can be set to High_Integrity with
-- a pragma if certifiable versions of all these routines are available,
-- in which case aggregates are permitted in HI-E mode. Otherwise the
-- HI-E compiler will reject any use of aggregates.
HIE_Composite_Assignments : Dummy;
-- The assignment of composite objects other than small records and
-- arrays whose size is 64-bits or less and is set by an explicit
-- size clause may generate calls to memcpy, memmove, and bcopy.
-- If certifiable versions of all these routines are available, then
-- this entity may be set to High_Integrity using a pragma, in which
-- case such assignments are permitted. Otherwise the HI-E compiler
-- will reject any such composite assignments.
end System.HIE_Back_End;
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