github.com/afumu/libc@v0.0.6/musl/src/math/i386/fmod.c (about)

     1  #include <math.h>
     2  
     3  double fmod(double x, double y)
     4  {
     5  	unsigned short fpsr;
     6  	// fprem does not introduce excess precision into x
     7  	do __asm__ ("fprem; fnstsw %%ax" : "+t"(x), "=a"(fpsr) : "u"(y));
     8  	while (fpsr & 0x400);
     9  	return x;
    10  }