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HP-UX Reference > F
fma(3M)HP Integrity Server OnlyHP-UX 11i Version 3: February 2007 |
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NAMEfma(), fmaf(), fmaw(), fmal(), fmaq() — floating multiply-add functions SYNOPSIS#include <math.h> double fma(double x, double y, double z); float fmaf(float x, float y, float z); long double fmal(long double x, long double y, long double z); extended fmaw(extended x, extended y, extended z); quad fmaq(quad x, quad y, quad z); DESCRIPTIONfma() returns (x*y) + z, rounded as one ternary operation: it computes the value (as if) to infinite precision and rounds once to the result format, according to the current rounding mode. fmaf() is a float version of fma(); it takes float arguments and returns a float result. fmal() is a long double version of fma(); it takes long double arguments and returns a long double result. fmaw() is an extended version of fma(); it takes extended arguments and returns an extended result. fmaq() is equivalent to fmal() on HP-UX systems. The FP_FAST_FMA, FP_FAST_FMAF, and FP_FAST_FMAW macros are defined in <math.h>, indicating that fma(), fmaf(), and fmaw() are each as fast as a multiply and add. USAGEThese functions are available only for Integrity servers. To use these functions, compile either with the default -Ae option or with the -Aa and -D_HPUX_SOURCE options. To use fmaw() or fmaq(), compile also with the -fpwidetypes option. To use these functions, make sure your program includes <math.h>. Link in the math library by specifying -lm on the compiler or linker command line. RETURN VALUEIf one of x and y is infinite, the other is zero, and z is a NaN, fma() returns NaN and optionally raises the invalid exception. If one of x and y is infinite, the other is zero, and z is not a NaN, fma() returns NaN and raises the invalid exception. If x times y is an exact infinity and z is also an infinity but with the opposite sign, fma() returns NaN and raises the invalid exception. fma() returns a properly signed infinity in lieu of a value whose magnitude is too large, and raise the overflow and inexact exceptions. fma() raises the underflow and inexact exceptions whenever a result is tiny (essentially denormal or zero) and thereby suffers loss of accuracy, and may raise those exceptions if the result is merely tiny. fma() raises the inexact exception whenever a rounded result does not equal the mathematical result. |
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