powerpc: Use faster means to access FPSCR when possible in some cases
[external/glibc.git] / sysdeps / powerpc / bits / fenvinline.h
1 /* Inline floating-point environment handling functions for powerpc.
2    Copyright (C) 1995-2019 Free Software Foundation, Inc.
3    This file is part of the GNU C Library.
4
5    The GNU C Library is free software; you can redistribute it and/or
6    modify it under the terms of the GNU Lesser General Public
7    License as published by the Free Software Foundation; either
8    version 2.1 of the License, or (at your option) any later version.
9
10    The GNU C Library is distributed in the hope that it will be useful,
11    but WITHOUT ANY WARRANTY; without even the implied warranty of
12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13    Lesser General Public License for more details.
14
15    You should have received a copy of the GNU Lesser General Public
16    License along with the GNU C Library; if not, see
17    <http://www.gnu.org/licenses/>.  */
18
19 #if defined __GNUC__ && !defined _SOFT_FLOAT && !defined __NO_FPRS__
20
21 /* Inline definitions for fegetround.  */
22 # define __fegetround_ISA300()                                          \
23   (__extension__  ({                                                    \
24     union { double __d; unsigned long long __ll; } __u;                 \
25     __asm__ __volatile__ (                                              \
26       ".machine push; .machine \"power9\"; mffsl %0; .machine pop"      \
27       : "=f" (__u.__d));                                                \
28     __u.__ll & 0x0000000000000003LL;                                    \
29   }))
30
31 # define __fegetround_ISA2()                                            \
32   (__extension__  ({                                                    \
33      int __fegetround_result;                                           \
34      __asm__ __volatile__ ("mcrfs 7,7 ; mfcr %0"                        \
35                            : "=r"(__fegetround_result) : : "cr7");      \
36      __fegetround_result & 3;                                           \
37   }))
38
39 # ifdef _ARCH_PWR9
40 #  define __fegetround() __fegetround_ISA300()
41 # elif defined __BUILTIN_CPU_SUPPORTS__
42 #  define __fegetround()                                                \
43   (__glibc_likely (__builtin_cpu_supports ("arch_3_00"))                \
44    ? __fegetround_ISA300()                                              \
45    : __fegetround_ISA2()                                                \
46   )
47 # else
48 #  define __fegetround() __fegetround_ISA2()
49 # endif
50
51 # define fegetround() __fegetround ()
52
53 # ifndef __NO_MATH_INLINES
54 /* The weird 'i#*X' constraints on the following suppress a gcc
55    warning when __excepts is not a constant.  Otherwise, they mean the
56    same as just plain 'i'.  */
57
58 #  if __GNUC_PREREQ(3, 4)
59
60 /* Inline definition for feraiseexcept.  */
61 #   define feraiseexcept(__excepts) \
62   (__extension__  ({                                                          \
63     int __e = __excepts;                                                      \
64     int __ret;                                                                \
65     if (__builtin_constant_p (__e)                                            \
66         && (__e & (__e - 1)) == 0                                             \
67         && __e != FE_INVALID)                                                 \
68       {                                                                       \
69         if (__e != 0)                                                         \
70           __asm__ __volatile__ ("mtfsb1 %0"                                   \
71                                 : : "i#*X" (__builtin_clz (__e)));            \
72         __ret = 0;                                                            \
73       }                                                                       \
74     else                                                                      \
75       __ret = feraiseexcept (__e);                                            \
76     __ret;                                                                    \
77   }))
78
79 /* Inline definition for feclearexcept.  */
80 #   define feclearexcept(__excepts) \
81   (__extension__  ({                                                          \
82     int __e = __excepts;                                                      \
83     int __ret;                                                                \
84     if (__builtin_constant_p (__e)                                            \
85         && (__e & (__e - 1)) == 0                                             \
86         && __e != FE_INVALID)                                                 \
87       {                                                                       \
88         if (__e != 0)                                                         \
89           __asm__ __volatile__ ("mtfsb0 %0"                                   \
90                                 : : "i#*X" (__builtin_clz (__e)));            \
91         __ret = 0;                                                            \
92       }                                                                       \
93     else                                                                      \
94       __ret = feclearexcept (__e);                                            \
95     __ret;                                                                    \
96   }))
97
98 #  endif /* __GNUC_PREREQ(3, 4).  */
99
100 # endif /* !__NO_MATH_INLINES.  */
101
102 #endif /* __GNUC__ && !_SOFT_FLOAT && !__NO_FPRS__ */