fma()

Computes a multiplication and addition.

  #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);

Parameter

x

The first multiplication value.

y

The second multiplication value.

z

The addition value.

Remarks

These functions compute and return (x * y) + z. These functions may be more accurate than using the compiler's regular multiplication (*) and addition (+) operators.

The functions compute this value to virtually infinite precision and apply rounding once to the result type according to the rounding mode specified by the FLT_ROUNDS.

If the result cannot be properly expressed in the result type, the functions set errno to EDOM and fpclassify(fdim(x, x)) does not return FP_NORMAL.

This facility may not be available on configurations of the EWL that run on platforms that do not have floating-point math capabilities.

Listing: Example of fma() usage


#include <math.h>

#include <stdio.h>

int main(void)

{

double k = 12;

double l = 4;

printf("|(%f - %f)| = %f\n", k, l, fma(k,l));

return 0;

}

Output:

| ( 12.000000 - 4.0000000 ) | = 8.0000000