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--                                                                          --

--                         GNAT RUN-TIME COMPONENTS                         --

--                                                                          --

--                 S Y S T E M . F L O A T _ C O N T R O L                  --

--                                                                          --

--                                 S p e c                                  --

--                                                                          --

--                     Copyright (C) 2000-2011, AdaCore                     --

--                                                                          --

-- 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.      --

--                                                                          --

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--  Control functions for floating-point unit

package System.Float_Control is

   pragma Pure;

   --  This is not fully correct, but this unit is with-ed by pure units

   --  (eg s-imgrea).

   procedure Reset;

   pragma Inline (Reset);

   --  Reset the floating-point processor to the default state needed to get

   --  correct Ada semantics for the target. Some third party tools change

   --  the settings for the floating-point processor. Reset can be called

   --  to reset the floating-point processor into the mode required by GNAT

   --  for correct operation. Use this call after a call to foreign code if

   --  you suspect incorrect floating-point operation after the call.

   --

   --  For example under Windows NT some system DLL calls change the default

   --  FPU arithmetic to 64 bit precision mode. However, since in Ada 95 it

   --  is required to provide full access to the floating-point types of the

   --  architecture, GNAT requires full 80-bit precision mode, and Reset makes

   --  sure this mode is established.

   --

   --  Similarly on the PPC processor, it is important that overflow and

   --  underflow exceptions be disabled.

   --

   --  The call to Reset simply has no effect if the target environment

   --  does not give rise to such concerns.

end System.Float_Control;