1    	/* Copyright (C) 1997-2015 Free Software Foundation, Inc.
2    	   This file is part of the GNU C Library.
3    	
4    	   The GNU C Library is free software; you can redistribute it and/or
5    	   modify it under the terms of the GNU Lesser General Public
6    	   License as published by the Free Software Foundation; either
7    	   version 2.1 of the License, or (at your option) any later version.
8    	
9    	   The GNU C Library is distributed in the hope that it will be useful,
10   	   but WITHOUT ANY WARRANTY; without even the implied warranty of
11   	   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
12   	   Lesser General Public License for more details.
13   	
14   	   You should have received a copy of the GNU Lesser General Public
15   	   License along with the GNU C Library; if not, see
16   	   <http://www.gnu.org/licenses/>.  */
17   	
18   	#ifndef _FENV_H
19   	# error "Never use <bits/fenv.h> directly; include <fenv.h> instead."
20   	#endif
21   	
22   	/* Define bits representing the exception.  We use the bit positions
23   	   of the appropriate bits in the FPU control word.  */
24   	enum
25   	  {
26   	    FE_INVALID =
27   	#define FE_INVALID	0x01
28   	      FE_INVALID,
29   	    __FE_DENORM = 0x02,
30   	    FE_DIVBYZERO =
31   	#define FE_DIVBYZERO	0x04
32   	      FE_DIVBYZERO,
33   	    FE_OVERFLOW =
34   	#define FE_OVERFLOW	0x08
35   	      FE_OVERFLOW,
36   	    FE_UNDERFLOW =
37   	#define FE_UNDERFLOW	0x10
38   	      FE_UNDERFLOW,
39   	    FE_INEXACT =
40   	#define FE_INEXACT	0x20
41   	      FE_INEXACT
42   	  };
43   	
44   	#define FE_ALL_EXCEPT \
45   		(FE_INEXACT | FE_DIVBYZERO | FE_UNDERFLOW | FE_OVERFLOW | FE_INVALID)
46   	
47   	/* The ix87 FPU supports all of the four defined rounding modes.  We
48   	   use again the bit positions in the FPU control word as the values
49   	   for the appropriate macros.  */
50   	enum
51   	  {
52   	    FE_TONEAREST =
53   	#define FE_TONEAREST	0
54   	      FE_TONEAREST,
55   	    FE_DOWNWARD =
56   	#define FE_DOWNWARD	0x400
57   	      FE_DOWNWARD,
58   	    FE_UPWARD =
59   	#define FE_UPWARD	0x800
60   	      FE_UPWARD,
61   	    FE_TOWARDZERO =
62   	#define FE_TOWARDZERO	0xc00
63   	      FE_TOWARDZERO
64   	  };
65   	
66   	
67   	/* Type representing exception flags.  */
68   	typedef unsigned short int fexcept_t;
69   	
70   	
71   	/* Type representing floating-point environment.  This structure
72   	   corresponds to the layout of the block written by the `fstenv'
73   	   instruction and has additional fields for the contents of the MXCSR
74   	   register as written by the `stmxcsr' instruction.  */
75   	typedef struct
76   	  {
77   	    unsigned short int __control_word;
78   	    unsigned short int __glibc_reserved1;
79   	    unsigned short int __status_word;
80   	    unsigned short int __glibc_reserved2;
81   	    unsigned short int __tags;
82   	    unsigned short int __glibc_reserved3;
83   	    unsigned int __eip;
84   	    unsigned short int __cs_selector;
85   	    unsigned int __opcode:11;
86   	    unsigned int __glibc_reserved4:5;
87   	    unsigned int __data_offset;
88   	    unsigned short int __data_selector;
89   	    unsigned short int __glibc_reserved5;
90   	#ifdef __x86_64__
91   	    unsigned int __mxcsr;
92   	#endif
93   	  }
94   	fenv_t;
95   	
96   	/* If the default argument is used we use this value.  */
97   	#define FE_DFL_ENV	((const fenv_t *) -1)
98   	
99   	#ifdef __USE_GNU
100  	/* Floating-point environment where none of the exception is masked.  */
101  	# define FE_NOMASK_ENV	((const fenv_t *) -2)
102  	#endif
103  	
104  	
105  	#ifdef __USE_EXTERN_INLINES
106  	__BEGIN_DECLS
107  	
108  	/* Optimized versions.  */
109  	extern int __REDIRECT_NTH (__feraiseexcept_renamed, (int), feraiseexcept);
110  	__extern_always_inline void
111  	__NTH (__feraiseexcept_invalid_divbyzero (int __excepts))
112  	{
113  	  if ((FE_INVALID & __excepts) != 0)
114  	    {
115  	      /* One example of an invalid operation is 0.0 / 0.0.  */
116  	      float __f = 0.0;
117  	
118  	# ifdef __SSE_MATH__
119  	      __asm__ __volatile__ ("divss %0, %0 " : : "x" (__f));
120  	# else
121  	      __asm__ __volatile__ ("fdiv %%st, %%st(0); fwait"
122  				    : "=t" (__f) : "0" (__f));
123  	# endif
124  	      (void) &__f;
125  	    }
126  	  if ((FE_DIVBYZERO & __excepts) != 0)
127  	    {
128  	      float __f = 1.0;
129  	      float __g = 0.0;
130  	
131  	# ifdef __SSE_MATH__
132  	      __asm__ __volatile__ ("divss %1, %0" : : "x" (__f), "x" (__g));
133  	# else
134  	      __asm__ __volatile__ ("fdivp %%st, %%st(1); fwait"
135  				    : "=t" (__f) : "0" (__f), "u" (__g) : "st(1)");
136  	# endif
137  	      (void) &__f;
138  	    }
139  	}
140  	__extern_inline int
141  	__NTH (feraiseexcept (int __excepts))
142  	{
143  	  if (__builtin_constant_p (__excepts)
144  	      && (__excepts & ~(FE_INVALID | FE_DIVBYZERO)) == 0)
145  	    {
146  	      __feraiseexcept_invalid_divbyzero (__excepts);
147  	      return 0;
148  	    }
149  	
150  	  return __feraiseexcept_renamed (__excepts);
151  	}
152  	
153  	__END_DECLS
154  	#endif
155