github.com/afumu/libc@v0.0.6/musl/src/math/fdimf.c (about)

     1  #include <math.h>
     2  
     3  float fdimf(float x, float y)
     4  {
     5  	if (isnan(x))
     6  		return x;
     7  	if (isnan(y))
     8  		return y;
     9  	return x > y ? x - y : 0;
    10  }