100 lines
6 KiB
Ada
100 lines
6 KiB
Ada
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------------------------------------------------------------------------------
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-- --
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-- GNAT RUN-TIME COMPONENTS --
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-- --
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-- S Y S T E M . H I E _ B A C K _ E N D --
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-- --
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-- S p e c --
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-- --
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-- Copyright (C) 2001-2009, Free Software Foundation, Inc. --
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-- --
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-- GNAT is free software; you can redistribute it and/or modify it under --
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-- terms of the GNU General Public License as published by the Free Soft- --
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-- ware Foundation; either version 3, or (at your option) any later ver- --
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-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
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-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
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-- or FITNESS FOR A PARTICULAR PURPOSE. --
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-- --
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-- As a special exception under Section 7 of GPL version 3, you are granted --
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-- additional permissions described in the GCC Runtime Library Exception, --
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-- version 3.1, as published by the Free Software Foundation. --
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-- --
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-- You should have received a copy of the GNU General Public License and --
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-- a copy of the GCC Runtime Library Exception along with this program; --
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-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
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-- <http://www.gnu.org/licenses/>. --
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-- --
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-- GNAT was originally developed by the GNAT team at New York University. --
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-- Extensive contributions were provided by Ada Core Technologies Inc. --
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-- --
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------------------------------------------------------------------------------
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-- This package provides an interface used in HI-E mode to determine
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-- whether or not the back end can handle certain constructs in a manner
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-- that is consistent with certification requirements.
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-- The approach is to define entities which may or may not be present in
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-- a HI-E configured library. If the entity is present then the compiler
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-- operating in HI-E mode will allow the corresponding operation. If the
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-- entity is not present, the corresponding construct will be flagged as
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-- not permitted in High Integrity mode.
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-- The default version of this unit delivered with the HI-E compiler is
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-- configured in a manner appropriate for the target, but it is possible
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-- to reconfigure the run-time to change the settings as required.
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-- This unit is not used and never accessed by the compiler unless it is
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-- operating in HI-E mode, so the settings are irrelevant. However, we
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-- do include a standard version with all entities present in the standard
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-- run-time for use when pragma No_Run_Time is specified.
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package System.HIE_Back_End is
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type Dummy is null record;
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pragma Suppress_Initialization (Dummy);
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-- This is the type used for the entities below. No properties of this
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-- type are ever referenced, and in particular, the entities are defined
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-- as variables, but their values are never referenced
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HIE_64_Bit_Divides : Dummy;
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-- This entity controls whether the front end allows 64-bit integer
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-- divide operations, including the case where division of 32-bit
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-- fixed-point operands requires 64-bit arithmetic. This can safely
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-- be set as High_Integrity on 64-bit machines which provide this
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-- operation as a native instruction, but on most 32-bit machines
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-- a run time call (e.g. to __divdi3 in gcclib) is required. If a
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-- certifiable version of this routine is available, then setting
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-- this entity to High_Integrity with a pragma will cause appropriate
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-- calls to be generated, allowing 64-bit integer division operations.
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HIE_Long_Shifts : Dummy;
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-- This entity controls whether the front end allows generation of
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-- long shift instructions, i.e. shifts that operate on 64-bit values.
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-- Such shifts are required for the implementation of fixed-point
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-- types longer than 32 bits. This can safely be set as High_Integrity
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-- on 64-bit machines that provide this operation at the hardware level,
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-- but on some 32-bit machines a run time call is required. If there
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-- is a certifiable version available of the relevant run-time routines,
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-- then setting this entity to High_Integrity with a pragma will cause
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-- appropriate calls to be generated, allowing the declaration and use
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-- of fixed-point types longer than 32 bits.
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HIE_Aggregates : Dummy;
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-- In the general case, the use of aggregates may generate calls
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-- to run-time routines in the C library, including memset, memcpy,
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-- memmove, and bcopy. This entity can be set to High_Integrity with
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-- a pragma if certifiable versions of all these routines are available,
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-- in which case aggregates are permitted in HI-E mode. Otherwise the
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-- HI-E compiler will reject any use of aggregates.
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HIE_Composite_Assignments : Dummy;
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-- The assignment of composite objects other than small records and
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-- arrays whose size is 64-bits or less and is set by an explicit
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-- size clause may generate calls to memcpy, memmove, and bcopy.
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-- If certifiable versions of all these routines are available, then
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-- this entity may be set to High_Integrity using a pragma, in which
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-- case such assignments are permitted. Otherwise the HI-E compiler
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-- will reject any such composite assignments.
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end System.HIE_Back_End;
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