diff options
Diffstat (limited to 'gcc/ginclude/float.h')
| -rw-r--r-- | gcc/ginclude/float.h | 72 |
1 files changed, 62 insertions, 10 deletions
diff --git a/gcc/ginclude/float.h b/gcc/ginclude/float.h index 421f735..3df2889 100644 --- a/gcc/ginclude/float.h +++ b/gcc/ginclude/float.h @@ -129,21 +129,73 @@ see the files COPYING3 and COPYING.RUNTIME respectively. If not, see #if (defined (__STDC_VERSION__) && __STDC_VERSION__ >= 199901L) \ || (defined (__cplusplus) && __cplusplus >= 201103L) -/* The floating-point expression evaluation method. - -1 indeterminate - 0 evaluate all operations and constants just to the range and - precision of the type - 1 evaluate operations and constants of type float and double - to the range and precision of the double type, evaluate - long double operations and constants to the range and - precision of the long double type - 2 evaluate all operations and constants to the range and - precision of the long double type +/* The floating-point expression evaluation method. The precise + definitions of these values are generalised to include support for + the interchange and extended types defined in ISO/IEC TS 18661-3. + Prior to this (for C99/C11) the definitions were: + + -1 indeterminate + 0 evaluate all operations and constants just to the range and + precision of the type + 1 evaluate operations and constants of type float and double + to the range and precision of the double type, evaluate + long double operations and constants to the range and + precision of the long double type + 2 evaluate all operations and constants to the range and + precision of the long double type + + The TS 18661-3 definitions are: + + -1 indeterminate + 0 evaluate all operations and constants, whose semantic type has + at most the range and precision of float, to the range and + precision of float; evaluate all other operations and constants + to the range and precision of the semantic type. + 1 evaluate all operations and constants, whose semantic type has + at most the range and precision of double, to the range and + precision of double; evaluate all other operations and constants + to the range and precision of the semantic type. + 2 evaluate all operations and constants, whose semantic type has + at most the range and precision of long double, to the range and + precision of long double; evaluate all other operations and + constants to the range and precision of the semantic type. + N where _FloatN is a supported interchange floating type + evaluate all operations and constants, whose semantic type has + at most the range and precision of the _FloatN type, to the + range and precision of the _FloatN type; evaluate all other + operations and constants to the range and precision of the + semantic type. + N + 1, where _FloatNx is a supported extended floating type + evaluate operations and constants, whose semantic type has at + most the range and precision of the _FloatNx type, to the range + and precision of the _FloatNx type; evaluate all other + operations and constants to the range and precision of the + semantic type. + + The compiler predefines two macros: + + __FLT_EVAL_METHOD__ + Which, depending on the value given for + -fpermitted-flt-eval-methods, may be limited to only those values + for FLT_EVAL_METHOD defined in C99/C11. + + __FLT_EVAL_METHOD_TS_18661_3__ + Which always permits the values for FLT_EVAL_METHOD defined in + ISO/IEC TS 18661-3. + + Here we want to use __FLT_EVAL_METHOD__, unless + __STDC_WANT_IEC_60559_TYPES_EXT__ is defined, in which case the user + is specifically asking for the ISO/IEC TS 18661-3 types, so we use + __FLT_EVAL_METHOD_TS_18661_3__. ??? This ought to change with the setting of the fp control word; the value provided by the compiler assumes the widest setting. */ #undef FLT_EVAL_METHOD +#ifdef __STDC_WANT_IEC_60559_TYPES_EXT__ +#define FLT_EVAL_METHOD __FLT_EVAL_METHOD_TS_18661_3__ +#else #define FLT_EVAL_METHOD __FLT_EVAL_METHOD__ +#endif /* Number of decimal digits, n, such that any floating-point number in the widest supported floating type with pmax radix b digits can be rounded |