sysdeps/x86_64/fpu/bits/fenv.h

   1 /* Copyright (C) 1997-2001,2004,2011 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, write to the Free
  16    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  17    02111-1307 USA.  */
  18
  19 #ifndef _FENV_H
  20 # error "Never use <bits/fenv.h> directly; include <fenv.h> instead."
  21 #endif
  22
  23 #include <bits/wordsize.h>
  24
  25
  26 /* Define bits representing the exception.  We use the bit positions
  27    of the appropriate bits in the FPU control word.  */
  28 enum
  29   {
  30     FE_INVALID = 0x01,
  31 #define FE_INVALID      FE_INVALID
  32     __FE_DENORM = 0x02,
  33     FE_DIVBYZERO = 0x04,
  34 #define FE_DIVBYZERO    FE_DIVBYZERO
  35     FE_OVERFLOW = 0x08,
  36 #define FE_OVERFLOW     FE_OVERFLOW
  37     FE_UNDERFLOW = 0x10,
  38 #define FE_UNDERFLOW    FE_UNDERFLOW
  39     FE_INEXACT = 0x20
  40 #define FE_INEXACT      FE_INEXACT
  41   };
  42
  43 #define FE_ALL_EXCEPT \
  44         (FE_INEXACT | FE_DIVBYZERO | FE_UNDERFLOW | FE_OVERFLOW | FE_INVALID)
  45
  46 /* The ix87 FPU supports all of the four defined rounding modes.  We
  47    use again the bit positions in the FPU control word as the values
  48    for the appropriate macros.  */
  49 enum
  50   {
  51     FE_TONEAREST = 0,
  52 #define FE_TONEAREST    FE_TONEAREST
  53     FE_DOWNWARD = 0x400,
  54 #define FE_DOWNWARD     FE_DOWNWARD
  55     FE_UPWARD = 0x800,
  56 #define FE_UPWARD       FE_UPWARD
  57     FE_TOWARDZERO = 0xc00
  58 #define FE_TOWARDZERO   FE_TOWARDZERO
  59   };
  60
  61
  62 /* Type representing exception flags.  */
  63 typedef unsigned short int fexcept_t;
  64
  65
  66 /* Type representing floating-point environment.  This structure
  67    corresponds to the layout of the block written by the `fstenv'
  68    instruction and has additional fields for the contents of the MXCSR
  69    register as written by the `stmxcsr' instruction.  */
  70 typedef struct
  71   {
  72     unsigned short int __control_word;
  73     unsigned short int __unused1;
  74     unsigned short int __status_word;
  75     unsigned short int __unused2;
  76     unsigned short int __tags;
  77     unsigned short int __unused3;
  78     unsigned int __eip;
  79     unsigned short int __cs_selector;
  80     unsigned int __opcode:11;
  81     unsigned int __unused4:5;
  82     unsigned int __data_offset;
  83     unsigned short int __data_selector;
  84     unsigned short int __unused5;
  85 #if __WORDSIZE == 64
  86     unsigned int __mxcsr;
  87 #endif
  88   }
  89 fenv_t;
  90
  91 /* If the default argument is used we use this value.  */
  92 #define FE_DFL_ENV      ((__const fenv_t *) -1)
  93
  94 #ifdef __USE_GNU
  95 /* Floating-point environment where none of the exception is masked.  */
  96 # define FE_NOMASK_ENV  ((__const fenv_t *) -2)
  97 #endif
  98
  99
 100 #ifdef __OPTIMIZE__
 101 /* Optimized versions.  */
 102 extern int __feraiseexcept_renamed (int) __asm__ ("feraiseexcept");
 103 __extern_inline int feraiseexcept (int __excepts)
 104 {
 105   if (__builtin_constant_p (__excepts)
 106       && (__excepts & ~(FE_INVALID | FE_DIVBYZERO)) == 0)
 107     {
 108       if ((FE_INVALID & __excepts) != 0)
 109         {
 110           /* One example of a invalid operation is 0.0 / 0.0.  */
 111           float __f = 0.0;
 112
 113           __asm__ __volatile__ ("divss %0, %0 " : : "x" (__f));
 114           (void) &__f;
 115         }
 116       if ((FE_DIVBYZERO & __excepts) != 0)
 117         {
 118           float f = 1.0;
 119           float g = 0.0;
 120
 121           __asm__ __volatile__ ("divss %1, %0" : : "x" (f), "x" (g));
 122           (void) &f;
 123         }
 124
 125       return 0;
 126     }
 127
 128   return __feraiseexcept_renamed (__excepts);
 129 }
 130 #endif