60 lines
3.6 KiB
Ada
60 lines
3.6 KiB
Ada
------------------------------------------------------------------------------
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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 . F L O A T _ C O N T R O L --
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-- --
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-- S p e c --
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-- --
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-- Copyright (C) 2000-2011, AdaCore --
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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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-- Control functions for floating-point unit
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package System.Float_Control is
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pragma Pure;
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-- This is not fully correct, but this unit is with-ed by pure units
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-- (eg s-imgrea).
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procedure Reset;
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pragma Inline (Reset);
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-- Reset the floating-point processor to the default state needed to get
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-- correct Ada semantics for the target. Some third party tools change
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-- the settings for the floating-point processor. Reset can be called
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-- to reset the floating-point processor into the mode required by GNAT
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-- for correct operation. Use this call after a call to foreign code if
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-- you suspect incorrect floating-point operation after the call.
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--
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-- For example under Windows NT some system DLL calls change the default
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-- FPU arithmetic to 64 bit precision mode. However, since in Ada 95 it
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-- is required to provide full access to the floating-point types of the
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-- architecture, GNAT requires full 80-bit precision mode, and Reset makes
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-- sure this mode is established.
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--
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-- Similarly on the PPC processor, it is important that overflow and
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-- underflow exceptions be disabled.
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--
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-- The call to Reset simply has no effect if the target environment
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-- does not give rise to such concerns.
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end System.Float_Control;
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