Floating-point extensions part 1: binary floating-point arithmetic
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Floating-point extensions for C - Part 1: Binary floating-point arithmetic, ISO/IEC TS 18661-1:2014, defines the following new components for the C standard library, as recommended by ISO/IEC/IEEE 60559:2011 (the current revision of IEEE-754)
| __STDC_IEC_60559_BFP__ |
integer constant of type long and value 201ymmL, replaces __STDC_IEC_559__ (macro constant) |
| __STDC_IEC_60559_COMPLEX__ |
integer constant of type long and value 201ymmL, replaces __STDC_IEC_559_COMPLEX__ (macro constant) |
| Defined in header
<limits.h> | |
| CHAR_WIDTH SCHAR_WIDTH UCHAR_WIDTHSHRT_WIDTH USHRT_WIDTHINT_WIDTH UINT_WIDTHLONG_WIDTH ULONG_WIDTHLLONG_WIDTH ULLONG_WIDTH (FP Ext 1 TS) |
width, in bits, of the corresponding type (macro constant) |
| Defined in header
<float.h> | |
| (FP Ext 1 TS) |
conversions between all supported binary floating-point types and character sequences with at most CR_DECIMAL_DIG significant decimal digits are correctly rounded (this is at least DECIMAL_DIG + 3) (macro constant) |
| Defined in header
<fenv.h> | |
| femode_t (FP Ext 1 TS) |
collection of dynamic floating-point control modes supported by the implementation, including the dynamic rounding direction mode (typedef) |
| FE_DFL_MODE (FP Ext 1 TS) |
pointer to the default femode_t (macro constant) |
| FE_SNANS_ALWAYS_SIGNAL (FP Ext 1 TS) |
defined (as integer constant 1) if sNaN arguments cause the functions that suppress qNaNs, like hypot or fmax, to raise FE_INVALID and return a qNaN (macro constant) |
| (FP Ext 1 TS) |
sets the specified floating-point exception flags without causing any side-effects that raising them would (function) |
| (FP Ext 1 TS) |
tests if given flags are in a saved representation of the floating-point exception flags (function) |
| (FP Ext 1 TS) |
gets and sets all the implementation’s dynamic floating-point control modes collectively (function) |
| Defined in header
<stdint.h> | |
| INTn_WIDTH UINTn_WIDTHINT_LEASTn_WIDTH UINT_LEASTn_WIDTHINT_FASTn_WIDTH UINT_FASTn_WIDTHINTPTR_WIDTH UINTPTR_WIDTHINTMAX_WIDTH UINTMAX_WIDTHPTRDIFF_WIDTHSIG_ATOMIC_WIDTHSIZE_WIDTHWCHAR_WIDTH WINT_WIDTH (FP Ext 1 TS) |
width, in bits, of the corresponding type (macro constant) |
| Defined in header
<stdlib.h> | |
| (FP Ext 1 TS) |
convert a single foating-point number to string using the specified snprintf format (function) |
| Defined in header
<math.h> | |
| FP_INT_UPWARDFP_INT_DOWNWARDFP_INT_TOWARDZERO
FP_INT_TONEARESTFROMZEROFP_INT_TONEAREST (FP Ext 1 TS) |
rounding direction for the functions ceil, floor, trunc, round, and roundeven, suitable for use with fromfp family of functions (macro constant) |
| FP_LLOGB0 (FP Ext 1 TS) |
value returned by llogb if the argument is zero (macro constant) |
| FP_LLOGBNAN (FP Ext 1 TS) |
value returned by llogb if the argument is NaN (macro constant) |
| (FP Ext 1 TS) |
represents a signalling NaN for float, double, long double respectively (macro constant) |
| FP_FAST_FADD FP_FAST_FADDL FP_FAST_DADDLFP_FAST_FSUB FP_FAST_FSUBL FP_FAST_DSUBLFP_FAST_FMUL FP_FAST_FMULL FP_FAST_DMULLFP_FAST_FDIV FP_FAST_FDIVL FP_FAST_DDIVLFP_FAST_FFMA FP_FAST_FFMAL FP_FAST_DFMALFP_FAST_FSQRT FP_FAST_FSQRTL FP_FAST_DSQRTL (FP Ext 1 TS) |
if defined, indicates that the corresponding function executes faster than the equivalent function in a larger type followed by a cast to target type (macro constant) |
| iseqsig (FP Ext 1 TS) |
(function macro) |
| iscanonical (FP Ext 1 TS) |
tests if the floating-point value is canonical (function macro) |
| issignaling (FP Ext 1 TS) |
tests if the floating-point value is a signalling NaN (function macro) |
| issubnormal (FP Ext 1 TS) |
tests if the floating-point value is subnormal (function macro) |
| iszero (FP Ext 1 TS) |
tests if the floating-point value is a zero (positive, negative, unsigned) (function macro) |
| (FP Ext 1 TS) |
round to signed integer using the specified rounding direction (function) |
| (FP Ext 1 TS) |
round to unsigned integer using the specified rounding direction (function) |
| (FP Ext 1 TS) |
round to signed integer using the specified rounding direction, reporting inexactness (function) |
| (FP Ext 1 TS) |
round to unsigned integer using the specified rounding direction, reporting inexactness (function) |
| (FP Ext 1 TS) |
rounds to nearest, halfway cases to even (function) |
| (FP Ext 1 TS) |
equivalent to logb except the return type is long (function) |
| (FP Ext 1 TS) |
returns the value of their argument of maximum magnitude (function) |
| (FP Ext 1 TS) |
returns the value of their argument of minimum magnitude (function) |
| (FP Ext 1 TS) |
returns the next greater representable floating-point value (function) |
| (FP Ext 1 TS) |
returns the next smaller representable floating-point value (function) |
| (FP Ext 1 TS) |
calculates x+y as if in infinite precision and rounded once to target type (function) |
| (FP Ext 1 TS) |
calculates x-y as if in infinite precision and rounded once to target type (function) |
| (FP Ext 1 TS) |
calculates x*y as if in infinite precision and rounded once to target type (function) |
| (FP Ext 1 TS) |
calculates x/y as if in infinite precision and rounded once to target type (function) |
| (FP Ext 1 TS) |
calculates the same as fma as if in infinite precision and rounded once to target type (function) |
| (FP Ext 1 TS) |
calculates the same as sqrt as if in infinite precision and rounded once to target type (function) |
| (FP Ext 1 TS) |
orders two floating-point values using the ISO 60559 total order relation (function) |
| (FP Ext 1 TS) |
orders the magnitudes of two floating-point values using the ISO 60559 total order relation (function) |
| (FP Ext 1 TS) |
obtains the ISO 60559 canonical binary encoding of the given floating-point value (function) |
| (FP Ext 1 TS) |
extracts the payload from the given NaN value (function) |
| (FP Ext 1 TS) |
creates a quiet NaN with the specified payload (function) |
| (FP Ext 1 TS) |
creates a signalling NaN with the specified payload (function) |
| Defined in header
<tgmath.h> | |
| roundeven (FP Ext 1 TS) |
generic overload of roundeven (function) |
| llogb (FP Ext 1 TS) |
generic overload of llogb (function) |
| fmaxmag (FP Ext 1 TS) |
generic overload of fmaxmag (function) |
| fminmag (FP Ext 1 TS) |
generic overload of fminmag (function) |
| nextup (FP Ext 1 TS) |
generic overload of nextup (function) |
| nextdown (FP Ext 1 TS) |
generic overload of nextdown (function) |
| fromfp (FP Ext 1 TS) |
generic overload of fromfp (function) |
| ufromfp (FP Ext 1 TS) |
generic overload of ufromfp (function) |
| fromfpx (FP Ext 1 TS) |
generic overload of fromfpx (function) |
| ufromfpx (FP Ext 1 TS) |
generic overload of ufromfpx (function) |
| nextdown (FP Ext 1 TS) |
generic overload of nextdown (function) |
| totalorder (FP Ext 1 TS) |
generic overload of totalorder (function) |
| totalordermag (FP Ext 1 TS) |
generic overload of totalordermag (function) |
| fadd (FP Ext 1 TS) |
generic overload of fadd (function) |
| dadd (FP Ext 1 TS) |
generic overload of dadd (function) |
| fsub (FP Ext 1 TS) |
generic overload of fsub (function) |
| dsub (FP Ext 1 TS) |
generic overload of dsub (function) |
| fmul (FP Ext 1 TS) |
generic overload of fmul (function) |
| dmul (FP Ext 1 TS) |
generic overload of dmul (function) |
| fdiv (FP Ext 1 TS) |
generic overload of fdiv (function) |
| ddiv (FP Ext 1 TS) |
generic overload of ddiv (function) |
| ffma (FP Ext 1 TS) |
generic overload of ffma (function) |
| dfma (FP Ext 1 TS) |
generic overload of dfma (function) |
| fsqrt (FP Ext 1 TS) |
generic overload of fsqrt (function) |
| dsqrt (FP Ext 1 TS) |
generic overload of dsqrt (function) |
Notes
The standard C macros __STDC_IEC_559__ and __STDC_IEC_559_COMPLEX__ are made obsolete by this technical specification.
All functions and macros added to the C library by this extension are only declared if a macro __STDC_WANT_IEC_60559_BFP_EXT__ is defined before the corresponding header is included.
Besides additions to the standard library, ISO/IEC TS 18661-1:2014 makes a number of changes to the core language, notably splitting floating-point control between static (controlled by the new #pragma STDC FENV_ROUND), and dynamic (controlled by fesetround). Most math.h functions respect the static rounding mode, if set, over the dynamic rounding mode.
| This section is incomplete Reason: add to the pragma page or describe the pragma in full here? |