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1 | /* Boost interval/detail/ppc_rounding_control.hpp file |
2 | * | |
3 | * Copyright 2000 Jens Maurer | |
b32b8144 | 4 | * Copyright 2002 Hervé Brönnimann, Guillaume Melquiond, Sylvain Pion |
7c673cae FG |
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 */ |