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

   1 /* Boost interval/detail/ppc_rounding_control.hpp file
   2  *
   3  * Copyright 2000 Jens Maurer
   4  * Copyright 2002 Hervé Brönnimann, Guillaume Melquiond, Sylvain Pion
   5  * Copyright 2005 Guillaume Melquiond
   6  *
   7  * Distributed under the Boost Software License, Version 1.0.
   8  * (See accompanying file LICENSE_1_0.txt or
   9  * copy at http://www.boost.org/LICENSE_1_0.txt)
  10  */
  11
  12 #ifndef BOOST_NUMERIC_INTERVAL_DETAIL_PPC_ROUNDING_CONTROL_HPP
  13 #define BOOST_NUMERIC_INTERVAL_DETAIL_PPC_ROUNDING_CONTROL_HPP
  14
  15 #if !defined(powerpc) && !defined(__powerpc__) && !defined(__ppc__)
  16 #error This header only works on PPC CPUs.
  17 #endif
  18
  19 #if defined(__GNUC__ ) || (__IBMCPP__ >= 700)
  20
  21 namespace boost {
  22 namespace numeric {
  23 namespace interval_lib {
  24 namespace detail {
  25
  26 typedef union {
  27    ::boost::long_long_type imode;
  28   double dmode;
  29 } rounding_mode_struct;
  30
  31 static const rounding_mode_struct mode_upward      = { 0xFFF8000000000002LL };
  32 static const rounding_mode_struct mode_downward    = { 0xFFF8000000000003LL };
  33 static const rounding_mode_struct mode_to_nearest  = { 0xFFF8000000000000LL };
  34 static const rounding_mode_struct mode_toward_zero = { 0xFFF8000000000001LL };
  35
  36 struct ppc_rounding_control
  37 {
  38   typedef double rounding_mode;
  39
  40   static void set_rounding_mode(const rounding_mode mode)
  41   { __asm__ __volatile__ ("mtfsf 255,%0" : : "f"(mode)); }
  42
  43   static void get_rounding_mode(rounding_mode& mode)
  44   { __asm__ __volatile__ ("mffs %0" : "=f"(mode)); }
  45
  46   static void downward()    { set_rounding_mode(mode_downward.dmode);    }
  47   static void upward()      { set_rounding_mode(mode_upward.dmode);      }
  48   static void to_nearest()  { set_rounding_mode(mode_to_nearest.dmode);  }
  49   static void toward_zero() { set_rounding_mode(mode_toward_zero.dmode); }
  50 };
  51
  52 } // namespace detail
  53
  54 // Do not declare the following C99 symbols if <math.h> provides them.
  55 // Otherwise, conflicts may occur, due to differences between prototypes.
  56 #if !defined(_ISOC99_SOURCE) && !defined(__USE_ISOC99)
  57 extern "C" {
  58   float rintf(float);
  59   double rint(double);
  60 }
  61 #endif
  62
  63 template<>
  64 struct rounding_control<float>:
  65   detail::ppc_rounding_control
  66 {
  67   static float force_rounding(const float r)
  68   {
  69     float tmp;
  70     __asm__ __volatile__ ("frsp %0, %1" : "=f" (tmp) : "f" (r));
  71     return tmp;
  72   }
  73   static float to_int(const float& x) { return rintf(x); }
  74 };
  75
  76 template<>
  77 struct rounding_control<double>:
  78   detail::ppc_rounding_control
  79 {
  80   static const double & force_rounding(const double& r) { return r; }
  81   static double to_int(const double& r) { return rint(r); }
  82 };
  83
  84 template<>
  85 struct rounding_control<long double>:
  86   detail::ppc_rounding_control
  87 {
  88   static const long double & force_rounding(const long double& r) { return r; }
  89   static long double to_int(const long double& r) { return rint(r); }
  90 };
  91
  92 } // namespace interval_lib
  93 } // namespace numeric
  94 } // namespace boost
  95
  96 #undef BOOST_NUMERIC_INTERVAL_NO_HARDWARE
  97 #endif
  98
  99 #endif /* BOOST_NUMERIC_INTERVAL_DETAIL_PPC_ROUNDING_CONTROL_HPP */