ceph/src/boost/libs/numeric/interval/include/boost/numeric/interval/detail/x86gcc_rounding_control.hpp

   1 /* Boost interval/detail/x86gcc_rounding_control.hpp file
   2  *
   3  * Copyright 2000 Jens Maurer
   4  * Copyright 2002 Hervé Brönnimann, Guillaume Melquiond, Sylvain Pion
   5  *
   6  * Distributed under the Boost Software License, Version 1.0.
   7  * (See accompanying file LICENSE_1_0.txt or
   8  * copy at http://www.boost.org/LICENSE_1_0.txt)
   9  */
  10
  11 #ifndef BOOST_NUMERIC_INTERVAL_DETAIL_X86GCC_ROUNDING_CONTROL_HPP
  12 #define BOOST_NUMERIC_INTERVAL_DETAIL_X86GCC_ROUNDING_CONTROL_HPP
  13
  14 #ifndef __GNUC__
  15 #  error This header only works with GNU CC.
  16 #endif
  17
  18 #ifndef __i386__
  19 #  error This header only works on x86 CPUs.
  20 #endif
  21
  22 namespace boost {
  23 namespace numeric {
  24 namespace interval_lib {
  25 namespace detail {
  26
  27 struct x86_rounding
  28 {
  29   typedef unsigned short rounding_mode;
  30
  31   static void set_rounding_mode(const rounding_mode& mode)
  32   { __asm__ __volatile__ ("fldcw %0" : : "m"(mode)); }
  33
  34   static void get_rounding_mode(rounding_mode& mode)
  35   { __asm__ __volatile__ ("fnstcw %0" : "=m"(mode)); }
  36
  37   template<class T>
  38   static T to_int(T r)
  39   {
  40     T r_;
  41     __asm__ ("frndint" : "=&t"(r_) : "0"(r));
  42     return r_;
  43   }
  44 };
  45
  46 } // namespace detail
  47 } // namespace interval_lib
  48 } // namespace numeric
  49 } // namespace boost
  50
  51 #endif /* BOOST_NUMERIC_INTERVAL_DETAIL_X86GCC_ROUNDING_CONTROL_HPP */