1------------------------------------------------------------------------------ 2-- -- 3-- GNAT RUN-TIME COMPONENTS -- 4-- -- 5-- S Y S T E M . F L O A T _ C O N T R O L -- 6-- -- 7-- S p e c -- 8-- -- 9-- Copyright (C) 2000-2011, AdaCore -- 10-- -- 11-- GNAT is free software; you can redistribute it and/or modify it under -- 12-- terms of the GNU General Public License as published by the Free Soft- -- 13-- ware Foundation; either version 3, or (at your option) any later ver- -- 14-- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- 15-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- 16-- or FITNESS FOR A PARTICULAR PURPOSE. -- 17-- -- 18-- As a special exception under Section 7 of GPL version 3, you are granted -- 19-- additional permissions described in the GCC Runtime Library Exception, -- 20-- version 3.1, as published by the Free Software Foundation. -- 21-- -- 22-- You should have received a copy of the GNU General Public License and -- 23-- a copy of the GCC Runtime Library Exception along with this program; -- 24-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see -- 25-- <http://www.gnu.org/licenses/>. -- 26-- -- 27-- GNAT was originally developed by the GNAT team at New York University. -- 28-- Extensive contributions were provided by Ada Core Technologies Inc. -- 29-- -- 30------------------------------------------------------------------------------ 31 32-- Control functions for floating-point unit 33 34package System.Float_Control is 35 pragma Pure; 36 -- This is not fully correct, but this unit is with-ed by pure units 37 -- (eg s-imgrea). 38 39 procedure Reset; 40 pragma Inline (Reset); 41 -- Reset the floating-point processor to the default state needed to get 42 -- correct Ada semantics for the target. Some third party tools change 43 -- the settings for the floating-point processor. Reset can be called 44 -- to reset the floating-point processor into the mode required by GNAT 45 -- for correct operation. Use this call after a call to foreign code if 46 -- you suspect incorrect floating-point operation after the call. 47 -- 48 -- For example under Windows NT some system DLL calls change the default 49 -- FPU arithmetic to 64 bit precision mode. However, since in Ada 95 it 50 -- is required to provide full access to the floating-point types of the 51 -- architecture, GNAT requires full 80-bit precision mode, and Reset makes 52 -- sure this mode is established. 53 -- 54 -- Similarly on the PPC processor, it is important that overflow and 55 -- underflow exceptions be disabled. 56 -- 57 -- The call to Reset simply has no effect if the target environment 58 -- does not give rise to such concerns. 59end System.Float_Control; 60