Floating-point extensions part 1: binary floating-point arithmetic
< c | experimental
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)
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__STDC_IEC_60559_BFP__
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integer constant of type long and value 201ymmL, replaces __STDC_IEC_559__ (macro constant) |
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__STDC_IEC_60559_COMPLEX__
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integer constant of type long and value 201ymmL, replaces __STDC_IEC_559_COMPLEX__ (macro constant) |
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Defined in header
<limits.h> |
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CHAR_WIDTH SCHAR_WIDTH UCHAR_WIDTHSHRT_WIDTH USHRT_WIDTHINT_WIDTH UINT_WIDTHLONG_WIDTH ULONG_WIDTHLLONG_WIDTH ULLONG_WIDTH
(FP Ext 1 TS)
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width, in bits, of the corresponding type (macro constant) |
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Defined in header
<float.h> |
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(FP Ext 1 TS)
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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) |
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Defined in header
<fenv.h> |
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femode_t
(FP Ext 1 TS)
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collection of dynamic floating-point control modes supported by the implementation, including the dynamic rounding direction mode (typedef) |
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FE_DFL_MODE
(FP Ext 1 TS)
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pointer to the default femode_t (macro constant) |
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FE_SNANS_ALWAYS_SIGNAL
(FP Ext 1 TS)
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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) |
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(FP Ext 1 TS)
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sets the specified floating-point exception flags without causing any side-effects that raising them would (function) |
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(FP Ext 1 TS)
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tests if given flags are in a saved representation of the floating-point exception flags (function) |
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(FP Ext 1 TS)
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gets and sets all the implementation’s dynamic floating-point control modes collectively (function) |
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Defined in header
<stdint.h> |
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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)
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width, in bits, of the corresponding type (macro constant) |
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Defined in header
<stdlib.h> |
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(FP Ext 1 TS)
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convert a single foating-point number to string using the specified snprintf format (function) |
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Defined in header
<math.h> |
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FP_INT_UPWARDFP_INT_DOWNWARDFP_INT_TOWARDZERO FP_INT_TONEARESTFROMZEROFP_INT_TONEAREST
(FP Ext 1 TS)
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rounding direction for the functions ceil, floor, trunc, round, and roundeven, suitable for use with fromfp family of functions (macro constant) |
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FP_LLOGB0
(FP Ext 1 TS)
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value returned by llogb if the argument is zero (macro constant) |
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FP_LLOGBNAN
(FP Ext 1 TS)
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value returned by llogb if the argument is NaN (macro constant) |
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(FP Ext 1 TS)
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represents a signalling NaN for float, double, long double respectively (macro constant) |
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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)
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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) |
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iseqsig
(FP Ext 1 TS)
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(function macro) |
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iscanonical
(FP Ext 1 TS)
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tests if the floating-point value is canonical (function macro) |
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issignaling
(FP Ext 1 TS)
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tests if the floating-point value is a signalling NaN (function macro) |
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issubnormal
(FP Ext 1 TS)
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tests if the floating-point value is subnormal (function macro) |
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iszero
(FP Ext 1 TS)
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tests if the floating-point value is a zero (positive, negative, unsigned) (function macro) |
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(FP Ext 1 TS)
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round to signed integer using the specified rounding direction (function) |
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(FP Ext 1 TS)
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round to unsigned integer using the specified rounding direction (function) |
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(FP Ext 1 TS)
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round to signed integer using the specified rounding direction, reporting inexactness (function) |
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(FP Ext 1 TS)
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round to unsigned integer using the specified rounding direction, reporting inexactness (function) |
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(FP Ext 1 TS)
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rounds to nearest, halfway cases to even (function) |
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(FP Ext 1 TS)
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equivalent to logb except the return type is long (function) |
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(FP Ext 1 TS)
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returns the value of their argument of maximum magnitude (function) |
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(FP Ext 1 TS)
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returns the value of their argument of minimum magnitude (function) |
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(FP Ext 1 TS)
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returns the next greater representable floating-point value (function) |
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(FP Ext 1 TS)
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returns the next smaller representable floating-point value (function) |
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(FP Ext 1 TS)
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calculates x+y as if in infinite precision and rounded once to target type (function) |
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(FP Ext 1 TS)
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calculates x-y as if in infinite precision and rounded once to target type (function) |
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(FP Ext 1 TS)
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calculates x*y as if in infinite precision and rounded once to target type (function) |
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(FP Ext 1 TS)
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calculates x/y as if in infinite precision and rounded once to target type (function) |
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(FP Ext 1 TS)
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calculates the same as fma as if in infinite precision and rounded once to target type (function) |
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(FP Ext 1 TS)
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calculates the same as sqrt as if in infinite precision and rounded once to target type (function) |
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(FP Ext 1 TS)
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orders two floating-point values using the ISO 60559 total order relation (function) |
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(FP Ext 1 TS)
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orders the magnitudes of two floating-point values using the ISO 60559 total order relation (function) |
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(FP Ext 1 TS)
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obtains the ISO 60559 canonical binary encoding of the given floating-point value (function) |
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(FP Ext 1 TS)
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extracts the payload from the given NaN value (function) |
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(FP Ext 1 TS)
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creates a quiet NaN with the specified payload (function) |
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(FP Ext 1 TS)
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creates a signalling NaN with the specified payload (function) |
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Defined in header
<tgmath.h> |
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roundeven
(FP Ext 1 TS)
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generic overload of roundeven (function) |
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llogb
(FP Ext 1 TS)
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generic overload of llogb (function) |
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fmaxmag
(FP Ext 1 TS)
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generic overload of fmaxmag (function) |
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fminmag
(FP Ext 1 TS)
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generic overload of fminmag (function) |
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nextup
(FP Ext 1 TS)
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generic overload of nextup (function) |
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nextdown
(FP Ext 1 TS)
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generic overload of nextdown (function) |
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fromfp
(FP Ext 1 TS)
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generic overload of fromfp (function) |
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ufromfp
(FP Ext 1 TS)
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generic overload of ufromfp (function) |
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fromfpx
(FP Ext 1 TS)
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generic overload of fromfpx (function) |
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ufromfpx
(FP Ext 1 TS)
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generic overload of ufromfpx (function) |
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nextdown
(FP Ext 1 TS)
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generic overload of nextdown (function) |
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totalorder
(FP Ext 1 TS)
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generic overload of totalorder (function) |
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totalordermag
(FP Ext 1 TS)
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generic overload of totalordermag (function) |
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fadd
(FP Ext 1 TS)
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generic overload of fadd (function) |
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dadd
(FP Ext 1 TS)
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generic overload of dadd (function) |
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fsub
(FP Ext 1 TS)
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generic overload of fsub (function) |
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dsub
(FP Ext 1 TS)
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generic overload of dsub (function) |
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fmul
(FP Ext 1 TS)
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generic overload of fmul (function) |
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dmul
(FP Ext 1 TS)
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generic overload of dmul (function) |
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fdiv
(FP Ext 1 TS)
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generic overload of fdiv (function) |
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ddiv
(FP Ext 1 TS)
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generic overload of ddiv (function) |
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ffma
(FP Ext 1 TS)
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generic overload of ffma (function) |
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dfma
(FP Ext 1 TS)
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generic overload of dfma (function) |
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fsqrt
(FP Ext 1 TS)
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generic overload of fsqrt (function) |
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dsqrt
(FP Ext 1 TS)
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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? |