| ------------------------------------------------------------------------------ |
| -- -- |
| -- 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) 2000-2021, 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. -- |
| -- -- |
| ------------------------------------------------------------------------------ |
| |
| -- 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; |
