sysdeps/powerpc/fpu/bits/fenv.h

   1 /* Copyright (C) 1997, 1998 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 Library General Public License as
   6    published by the Free Software Foundation; either version 2 of the
   7    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    Library General Public License for more details.
  13
  14    You should have received a copy of the GNU Library General Public
  15    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  16    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  17    Boston, MA 02111-1307, USA.  */
  18
  19 #ifndef _FENV_H
  20 # error "Never use <bits/fenv.h> directly; include <fenv.h> instead."
  21 #endif
  22
  23
  24 /* Define bits representing the exception.  We use the bit positions of
  25    the appropriate bits in the FPSCR...  */
  26 enum
  27   {
  28     FE_INEXACT = 1 << (31 - 6),
  29 #define FE_INEXACT      FE_INEXACT
  30     FE_DIVBYZERO = 1 << (31 - 5),
  31 #define FE_DIVBYZERO    FE_DIVBYZERO
  32     FE_UNDERFLOW = 1 << (31 - 4),
  33 #define FE_UNDERFLOW    FE_UNDERFLOW
  34     FE_OVERFLOW = 1 << (31 - 3),
  35 #define FE_OVERFLOW     FE_OVERFLOW
  36
  37     /* ... except for FE_INVALID, for which we use bit 31. FE_INVALID
  38        actually corresponds to bits 7 through 12 and 21 through 23
  39        in the FPSCR, but we can't use that because the current draft
  40        says that it must be a power of 2.  Instead we use bit 2 which
  41        is the summary bit for all the FE_INVALID exceptions, which
  42        kind of makes sense.  */
  43     FE_INVALID = 1 << (31 - 2),
  44 #define FE_INVALID      FE_INVALID
  45
  46 #ifdef __USE_GNU
  47     /* Breakdown of the FE_INVALID bits. Setting FE_INVALID on an
  48        input to a routine is equivalent to setting all of these bits;
  49        FE_INVALID will be set on output from a routine iff one of
  50        these bits is set.  Note, though, that you can't disable or
  51        enable these exceptions individually.  */
  52
  53     /* Operation with SNaN. */
  54     FE_INVALID_SNAN = 1 << (31 - 7),
  55 # define FE_INVALID_SNAN        FE_INVALID_SNAN
  56
  57     /* Inf - Inf */
  58     FE_INVALID_ISI = 1 << (31 - 8),
  59 # define FE_INVALID_ISI         FE_INVALID_ISI
  60
  61     /* Inf / Inf */
  62     FE_INVALID_IDI = 1 << (31 - 9),
  63 # define FE_INVALID_IDI         FE_INVALID_IDI
  64
  65     /* 0 / 0 */
  66     FE_INVALID_ZDZ = 1 << (31 - 10),
  67 # define FE_INVALID_ZDZ         FE_INVALID_ZDZ
  68
  69     /* Inf * 0 */
  70     FE_INVALID_IMZ = 1 << (31 - 11),
  71 # define FE_INVALID_IMZ         FE_INVALID_IMZ
  72
  73     /* Comparison with NaN or SNaN.  */
  74     FE_INVALID_COMPARE = 1 << (31 - 12),
  75 # define FE_INVALID_COMPARE     FE_INVALID_COMPARE
  76
  77     /* Invalid operation flag for software (not set by hardware).  */
  78     /* Note that some chips don't have this implemented, presumably
  79        because no-one expected anyone to write software for them %-).  */
  80     FE_INVALID_SOFTWARE = 1 << (31 - 21),
  81 # define FE_INVALID_SOFTWARE    FE_INVALID_SOFTWARE
  82
  83     /* Square root of negative number (including -Inf).  */
  84     /* Note that some chips don't have this implemented.  */
  85     FE_INVALID_SQRT = 1 << (31 - 22),
  86 # define FE_INVALID_SQRT        FE_INVALID_SQRT
  87
  88     /* Conversion-to-integer of a NaN or a number too large or too small.  */
  89     FE_INVALID_INTEGER_CONVERSION = 1 << (31 - 23)
  90 # define FE_INVALID_INTEGER_CONVERSION  FE_INVALID_INTEGER_CONVERSION
  91
  92 # define FE_ALL_INVALID \
  93         (FE_INVALID_SNAN | FE_INVALID_ISI | FE_INVALID_IDI | FE_INVALID_ZDZ \
  94          | FE_INVALID_IMZ | FE_INVALID_COMPARE | FE_INVALID_SOFTWARE \
  95          | FE_INVALID_SQRT | FE_INVALID_INTEGER_CONVERSION)
  96 #endif
  97   };
  98
  99 #define FE_ALL_EXCEPT \
 100         (FE_INEXACT | FE_DIVBYZERO | FE_UNDERFLOW | FE_OVERFLOW | FE_INVALID)
 101
 102 /* PowerPC chips support all of the four defined rounding modes.  We
 103    use the bit pattern in the FPSCR as the values for the
 104    appropriate macros.  */
 105 enum
 106   {
 107     FE_TONEAREST = 0,
 108 #define FE_TONEAREST    FE_TONEAREST
 109     FE_TOWARDZERO = 1,
 110 #define FE_TOWARDZERO   FE_TOWARDZERO
 111     FE_UPWARD = 2,
 112 #define FE_UPWARD       FE_UPWARD
 113     FE_DOWNWARD = 3
 114 #define FE_DOWNWARD     FE_DOWNWARD
 115   };
 116
 117 /* Type representing exception flags.  */
 118 typedef unsigned int fexcept_t;
 119
 120 /* Type representing floating-point environment.  We leave it as 'double'
 121    for efficiency reasons (rather than writing it to a 32-bit integer). */
 122 typedef double fenv_t;
 123
 124 /* If the default argument is used we use this value.  */
 125 extern const fenv_t __fe_dfl_env;
 126 #define FE_DFL_ENV      (&__fe_dfl_env)
 127
 128 #ifdef __USE_GNU
 129 /* Floating-point environment where all exceptions are enabled.  Note that
 130    this is not sufficient to give you SIGFPE.  */
 131 extern const fenv_t __fe_enabled_env;
 132 # define FE_ENABLED_ENV (&__fe_enabled_env)
 133
 134 /* Floating-point environment with (processor-dependent) non-IEEE floating
 135    point.  */
 136 extern const fenv_t __fe_nonieee_env;
 137 # define FE_NONIEEE_ENV (&__fe_nonieee_env)
 138
 139 /* Floating-point environment with all exceptions enabled.  Note that
 140    just evaluating this value will set the processor into 'FPU
 141    exceptions imprecise recoverable' mode, which may cause a significant
 142    performance penalty (but have no other visible effect).  */
 143 extern const fenv_t *__fe_nomask_env __P ((void));
 144 # define FE_NOMASK_ENV  (__fe_nomask_env ())
 145 #endif
 146
 147 #if defined __OPTIMIZE__ && !defined _SOFT_FLOAT
 148 /* Inline definition for fegetround.  */
 149 # define fegetround() \
 150   (__extension__  ({ int __fegetround_result;                                 \
 151                      __asm__ ("mcrfs 7,7 ; mfcr %0"                           \
 152                              : "=r"(__fegetround_result) : : "cr7");          \
 153                      __fegetround_result & 3; }))
 154
 155 /* The weird 'i#*X' constraints on the following suppress a gcc
 156    warning when __excepts is not a constant.  Otherwise, they mean the
 157    same as just plain 'i'.  */
 158
 159 /* Inline definition for feraiseexcept.  */
 160 # define feraiseexcept(__excepts) \
 161   ((__builtin_constant_p (__excepts)                                          \
 162     && ((__excepts) & ((__excepts)-1)) == 0                                   \
 163     && (__excepts) != FE_INVALID)                                             \
 164    ? ((__excepts) != 0                                                        \
 165       ? (__extension__ ({ __asm__ __volatile__                                \
 166                           ("mtfsb1 %s0"                                       \
 167                            : : "i#*X"(__builtin_ffs (__excepts)));            \
 168                           (void)0; }))                                        \
 169       : (void)0)                                                              \
 170    : (feraiseexcept) (__excepts))
 171
 172 /* Inline definition for feclearexcept.  */
 173 # define feclearexcept(__excepts) \
 174   ((__builtin_constant_p (__excepts)                                          \
 175     && ((__excepts) & ((__excepts)-1)) == 0                                   \
 176     && (__excepts) != FE_INVALID)                                             \
 177    ? ((__excepts) != 0                                                        \
 178       ? (__extension__ ({ __asm__ __volatile__                                \
 179                           ("mtfsb0 %s0"                                       \
 180                            : : "i#*X"(__builtin_ffs (__excepts)));            \
 181                           (void)0; }))                                        \
 182       : (void)0)                                                              \
 183    : (feclearexcept) (__excepts))
 184 #endif /* __OPTIMIZE__ && !_SOFT_FLOAT */